gcc/tree.c

   1 /* Language-independent node constructors for parse phase of GNU compiler.
   2    Copyright (C) 1987, 1988, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
   3    1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007
   4    Free Software Foundation, Inc.
   5
   6 This file is part of GCC.
   7
   8 GCC is free software; you can redistribute it and/or modify it under
   9 the terms of the GNU General Public License as published by the Free
  10 Software Foundation; either version 2, or (at your option) any later
  11 version.
  12
  13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  15 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  16 for more details.
  17
  18 You should have received a copy of the GNU General Public License
  19 along with GCC; see the file COPYING.  If not, write to the Free
  20 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
  21 02110-1301, USA.  */
  22
  23 /* This file contains the low level primitives for operating on tree nodes,
  24    including allocation, list operations, interning of identifiers,
  25    construction of data type nodes and statement nodes,
  26    and construction of type conversion nodes.  It also contains
  27    tables index by tree code that describe how to take apart
  28    nodes of that code.
  29
  30    It is intended to be language-independent, but occasionally
  31    calls language-dependent routines defined (for C) in typecheck.c.  */
  32
  33 #include "config.h"
  34 #include "system.h"
  35 #include "coretypes.h"
  36 #include "tm.h"
  37 #include "flags.h"
  38 #include "tree.h"
  39 #include "real.h"
  40 #include "tm_p.h"
  41 #include "function.h"
  42 #include "obstack.h"
  43 #include "toplev.h"
  44 #include "ggc.h"
  45 #include "hashtab.h"
  46 #include "output.h"
  47 #include "target.h"
  48 #include "langhooks.h"
  49 #include "tree-iterator.h"
  50 #include "basic-block.h"
  51 #include "tree-flow.h"
  52 #include "params.h"
  53 #include "pointer-set.h"
  54
  55 /* Each tree code class has an associated string representation.
  56    These must correspond to the tree_code_class entries.  */
  57
  58 const char *const tree_code_class_strings[] =
  59 {
  60   "exceptional",
  61   "constant",
  62   "type",
  63   "declaration",
  64   "reference",
  65   "comparison",
  66   "unary",
  67   "binary",
  68   "statement",
  69   "expression",
  70 };
  71
  72 /* obstack.[ch] explicitly declined to prototype this.  */
  73 extern int _obstack_allocated_p (struct obstack *h, void *obj);
  74
  75 #ifdef GATHER_STATISTICS
  76 /* Statistics-gathering stuff.  */
  77
  78 int tree_node_counts[(int) all_kinds];
  79 int tree_node_sizes[(int) all_kinds];
  80
  81 /* Keep in sync with tree.h:enum tree_node_kind.  */
  82 static const char * const tree_node_kind_names[] = {
  83   "decls",
  84   "types",
  85   "blocks",
  86   "stmts",
  87   "refs",
  88   "exprs",
  89   "constants",
  90   "identifiers",
  91   "perm_tree_lists",
  92   "temp_tree_lists",
  93   "vecs",
  94   "binfos",
  95   "phi_nodes",
  96   "ssa names",
  97   "constructors",
  98   "random kinds",
  99   "lang_decl kinds",
 100   "lang_type kinds",
 101   "omp clauses",
 102   "gimple statements"
 103 };
 104 #endif /* GATHER_STATISTICS */
 105
 106 /* Unique id for next decl created.  */
 107 static GTY(()) int next_decl_uid;
 108 /* Unique id for next type created.  */
 109 static GTY(()) int next_type_uid = 1;
 110
 111 /* Since we cannot rehash a type after it is in the table, we have to
 112    keep the hash code.  */
 113
 114 struct type_hash GTY(())
 115 {
 116   unsigned long hash;
 117   tree type;
 118 };
 119
 120 /* Initial size of the hash table (rounded to next prime).  */
 121 #define TYPE_HASH_INITIAL_SIZE 1000
 122
 123 /* Now here is the hash table.  When recording a type, it is added to
 124    the slot whose index is the hash code.  Note that the hash table is
 125    used for several kinds of types (function types, array types and
 126    array index range types, for now).  While all these live in the
 127    same table, they are completely independent, and the hash code is
 128    computed differently for each of these.  */
 129
 130 static GTY ((if_marked ("type_hash_marked_p"), param_is (struct type_hash)))
 131      htab_t type_hash_table;
 132
 133 /* Hash table and temporary node for larger integer const values.  */
 134 static GTY (()) tree int_cst_node;
 135 static GTY ((if_marked ("ggc_marked_p"), param_is (union tree_node)))
 136      htab_t int_cst_hash_table;
 137
 138 /* General tree->tree mapping  structure for use in hash tables.  */
 139
 140
 141 static GTY ((if_marked ("tree_map_marked_p"), param_is (struct tree_map)))
 142      htab_t debug_expr_for_decl;
 143
 144 static GTY ((if_marked ("tree_map_marked_p"), param_is (struct tree_map)))
 145      htab_t value_expr_for_decl;
 146
 147 static GTY ((if_marked ("tree_int_map_marked_p"), param_is (struct tree_int_map)))
 148   htab_t init_priority_for_decl;
 149
 150 static GTY ((if_marked ("tree_map_marked_p"), param_is (struct tree_map)))
 151   htab_t restrict_base_for_decl;
 152
 153 struct tree_int_map GTY(())
 154 {
 155   tree from;
 156   unsigned short to;
 157 };
 158 static unsigned int tree_int_map_hash (const void *);
 159 static int tree_int_map_eq (const void *, const void *);
 160 static int tree_int_map_marked_p (const void *);
 161 static void set_type_quals (tree, int);
 162 static int type_hash_eq (const void *, const void *);
 163 static hashval_t type_hash_hash (const void *);
 164 static hashval_t int_cst_hash_hash (const void *);
 165 static int int_cst_hash_eq (const void *, const void *);
 166 static void print_type_hash_statistics (void);
 167 static void print_debug_expr_statistics (void);
 168 static void print_value_expr_statistics (void);
 169 static int type_hash_marked_p (const void *);
 170 static unsigned int type_hash_list (tree, hashval_t);
 171 static unsigned int attribute_hash_list (tree, hashval_t);
 172
 173 tree global_trees[TI_MAX];
 174 tree integer_types[itk_none];
 175
 176 unsigned char tree_contains_struct[256][64];
 177
 178 /* Number of operands for each OpenMP clause.  */
 179 unsigned const char omp_clause_num_ops[] =
 180 {
 181   0, /* OMP_CLAUSE_ERROR  */
 182   1, /* OMP_CLAUSE_PRIVATE  */
 183   1, /* OMP_CLAUSE_SHARED  */
 184   1, /* OMP_CLAUSE_FIRSTPRIVATE  */
 185   1, /* OMP_CLAUSE_LASTPRIVATE  */
 186   4, /* OMP_CLAUSE_REDUCTION  */
 187   1, /* OMP_CLAUSE_COPYIN  */
 188   1, /* OMP_CLAUSE_COPYPRIVATE  */
 189   1, /* OMP_CLAUSE_IF  */
 190   1, /* OMP_CLAUSE_NUM_THREADS  */
 191   1, /* OMP_CLAUSE_SCHEDULE  */
 192   0, /* OMP_CLAUSE_NOWAIT  */
 193   0, /* OMP_CLAUSE_ORDERED  */
 194   0  /* OMP_CLAUSE_DEFAULT  */
 195 };
 196
 197 const char * const omp_clause_code_name[] =
 198 {
 199   "error_clause",
 200   "private",
 201   "shared",
 202   "firstprivate",
 203   "lastprivate",
 204   "reduction",
 205   "copyin",
 206   "copyprivate",
 207   "if",
 208   "num_threads",
 209   "schedule",
 210   "nowait",
 211   "ordered",
 212   "default"
 213 };
 214 \f
 215 /* Init tree.c.  */
 216
 217 void
 218 init_ttree (void)
 219 {
 220   /* Initialize the hash table of types.  */
 221   type_hash_table = htab_create_ggc (TYPE_HASH_INITIAL_SIZE, type_hash_hash,
 222                                      type_hash_eq, 0);
 223
 224   debug_expr_for_decl = htab_create_ggc (512, tree_map_hash,
 225                                          tree_map_eq, 0);
 226
 227   value_expr_for_decl = htab_create_ggc (512, tree_map_hash,
 228                                          tree_map_eq, 0);
 229   init_priority_for_decl = htab_create_ggc (512, tree_int_map_hash,
 230                                             tree_int_map_eq, 0);
 231   restrict_base_for_decl = htab_create_ggc (256, tree_map_hash,
 232                                             tree_map_eq, 0);
 233
 234   int_cst_hash_table = htab_create_ggc (1024, int_cst_hash_hash,
 235                                         int_cst_hash_eq, NULL);
 236
 237   int_cst_node = make_node (INTEGER_CST);
 238
 239   tree_contains_struct[FUNCTION_DECL][TS_DECL_NON_COMMON] = 1;
 240   tree_contains_struct[TRANSLATION_UNIT_DECL][TS_DECL_NON_COMMON] = 1;
 241   tree_contains_struct[TYPE_DECL][TS_DECL_NON_COMMON] = 1;
 242
 243
 244   tree_contains_struct[CONST_DECL][TS_DECL_COMMON] = 1;
 245   tree_contains_struct[VAR_DECL][TS_DECL_COMMON] = 1;
 246   tree_contains_struct[PARM_DECL][TS_DECL_COMMON] = 1;
 247   tree_contains_struct[RESULT_DECL][TS_DECL_COMMON] = 1;
 248   tree_contains_struct[FUNCTION_DECL][TS_DECL_COMMON] = 1;
 249   tree_contains_struct[TYPE_DECL][TS_DECL_COMMON] = 1;
 250   tree_contains_struct[TRANSLATION_UNIT_DECL][TS_DECL_COMMON] = 1;
 251   tree_contains_struct[LABEL_DECL][TS_DECL_COMMON] = 1;
 252   tree_contains_struct[FIELD_DECL][TS_DECL_COMMON] = 1;
 253
 254
 255   tree_contains_struct[CONST_DECL][TS_DECL_WRTL] = 1;
 256   tree_contains_struct[VAR_DECL][TS_DECL_WRTL] = 1;
 257   tree_contains_struct[PARM_DECL][TS_DECL_WRTL] = 1;
 258   tree_contains_struct[RESULT_DECL][TS_DECL_WRTL] = 1;
 259   tree_contains_struct[FUNCTION_DECL][TS_DECL_WRTL] = 1;
 260   tree_contains_struct[LABEL_DECL][TS_DECL_WRTL] = 1;
 261
 262   tree_contains_struct[CONST_DECL][TS_DECL_MINIMAL] = 1;
 263   tree_contains_struct[VAR_DECL][TS_DECL_MINIMAL] = 1;
 264   tree_contains_struct[PARM_DECL][TS_DECL_MINIMAL] = 1;
 265   tree_contains_struct[RESULT_DECL][TS_DECL_MINIMAL] = 1;
 266   tree_contains_struct[FUNCTION_DECL][TS_DECL_MINIMAL] = 1;
 267   tree_contains_struct[TYPE_DECL][TS_DECL_MINIMAL] = 1;
 268   tree_contains_struct[TRANSLATION_UNIT_DECL][TS_DECL_MINIMAL] = 1;
 269   tree_contains_struct[LABEL_DECL][TS_DECL_MINIMAL] = 1;
 270   tree_contains_struct[FIELD_DECL][TS_DECL_MINIMAL] = 1;
 271   tree_contains_struct[STRUCT_FIELD_TAG][TS_DECL_MINIMAL] = 1;
 272   tree_contains_struct[NAME_MEMORY_TAG][TS_DECL_MINIMAL] = 1;
 273   tree_contains_struct[SYMBOL_MEMORY_TAG][TS_DECL_MINIMAL] = 1;
 274   tree_contains_struct[MEMORY_PARTITION_TAG][TS_DECL_MINIMAL] = 1;
 275
 276   tree_contains_struct[STRUCT_FIELD_TAG][TS_MEMORY_TAG] = 1;
 277   tree_contains_struct[NAME_MEMORY_TAG][TS_MEMORY_TAG] = 1;
 278   tree_contains_struct[SYMBOL_MEMORY_TAG][TS_MEMORY_TAG] = 1;
 279   tree_contains_struct[MEMORY_PARTITION_TAG][TS_MEMORY_TAG] = 1;
 280
 281   tree_contains_struct[STRUCT_FIELD_TAG][TS_STRUCT_FIELD_TAG] = 1;
 282   tree_contains_struct[MEMORY_PARTITION_TAG][TS_MEMORY_PARTITION_TAG] = 1;
 283
 284   tree_contains_struct[VAR_DECL][TS_DECL_WITH_VIS] = 1;
 285   tree_contains_struct[FUNCTION_DECL][TS_DECL_WITH_VIS] = 1;
 286   tree_contains_struct[TYPE_DECL][TS_DECL_WITH_VIS] = 1;
 287   tree_contains_struct[TRANSLATION_UNIT_DECL][TS_DECL_WITH_VIS] = 1;
 288
 289   tree_contains_struct[VAR_DECL][TS_VAR_DECL] = 1;
 290   tree_contains_struct[FIELD_DECL][TS_FIELD_DECL] = 1;
 291   tree_contains_struct[PARM_DECL][TS_PARM_DECL] = 1;
 292   tree_contains_struct[LABEL_DECL][TS_LABEL_DECL] = 1;
 293   tree_contains_struct[RESULT_DECL][TS_RESULT_DECL] = 1;
 294   tree_contains_struct[CONST_DECL][TS_CONST_DECL] = 1;
 295   tree_contains_struct[TYPE_DECL][TS_TYPE_DECL] = 1;
 296   tree_contains_struct[FUNCTION_DECL][TS_FUNCTION_DECL] = 1;
 297
 298   lang_hooks.init_ts ();
 299 }
 300
 301 \f
 302 /* The name of the object as the assembler will see it (but before any
 303    translations made by ASM_OUTPUT_LABELREF).  Often this is the same
 304    as DECL_NAME.  It is an IDENTIFIER_NODE.  */
 305 tree
 306 decl_assembler_name (tree decl)
 307 {
 308   if (!DECL_ASSEMBLER_NAME_SET_P (decl))
 309     lang_hooks.set_decl_assembler_name (decl);
 310   return DECL_WITH_VIS_CHECK (decl)->decl_with_vis.assembler_name;
 311 }
 312
 313 /* Compare ASMNAME with the DECL_ASSEMBLER_NAME of DECL.  */
 314
 315 bool
 316 decl_assembler_name_equal (tree decl, tree asmname)
 317 {
 318   tree decl_asmname = DECL_ASSEMBLER_NAME (decl);
 319
 320   if (decl_asmname == asmname)
 321     return true;
 322
 323   /* If the target assembler name was set by the user, things are trickier.
 324      We have a leading '*' to begin with.  After that, it's arguable what
 325      is the correct thing to do with -fleading-underscore.  Arguably, we've
 326      historically been doing the wrong thing in assemble_alias by always
 327      printing the leading underscore.  Since we're not changing that, make
 328      sure user_label_prefix follows the '*' before matching.  */
 329   if (IDENTIFIER_POINTER (decl_asmname)[0] == '*')
 330     {
 331       const char *decl_str = IDENTIFIER_POINTER (decl_asmname) + 1;
 332       size_t ulp_len = strlen (user_label_prefix);
 333
 334       if (ulp_len == 0)
 335         ;
 336       else if (strncmp (decl_str, user_label_prefix, ulp_len) == 0)
 337         decl_str += ulp_len;
 338       else
 339         return false;
 340
 341       return strcmp (decl_str, IDENTIFIER_POINTER (asmname)) == 0;
 342     }
 343
 344   return false;
 345 }
 346
 347 /* Compute the number of bytes occupied by a tree with code CODE.
 348    This function cannot be used for TREE_VEC, PHI_NODE, or STRING_CST
 349    codes, which are of variable length.  */
 350 size_t
 351 tree_code_size (enum tree_code code)
 352 {
 353   switch (TREE_CODE_CLASS (code))
 354     {
 355     case tcc_declaration:  /* A decl node */
 356       {
 357         switch (code)
 358           {
 359           case FIELD_DECL:
 360             return sizeof (struct tree_field_decl);
 361           case PARM_DECL:
 362             return sizeof (struct tree_parm_decl);
 363           case VAR_DECL:
 364             return sizeof (struct tree_var_decl);
 365           case LABEL_DECL:
 366             return sizeof (struct tree_label_decl);
 367           case RESULT_DECL:
 368             return sizeof (struct tree_result_decl);
 369           case CONST_DECL:
 370             return sizeof (struct tree_const_decl);
 371           case TYPE_DECL:
 372             return sizeof (struct tree_type_decl);
 373           case FUNCTION_DECL:
 374             return sizeof (struct tree_function_decl);
 375           case NAME_MEMORY_TAG:
 376           case SYMBOL_MEMORY_TAG:
 377             return sizeof (struct tree_memory_tag);
 378           case STRUCT_FIELD_TAG:
 379             return sizeof (struct tree_struct_field_tag);
 380           case MEMORY_PARTITION_TAG:
 381             return sizeof (struct tree_memory_partition_tag);
 382           default:
 383             return sizeof (struct tree_decl_non_common);
 384           }
 385       }
 386
 387     case tcc_type:  /* a type node */
 388       return sizeof (struct tree_type);
 389
 390     case tcc_reference:   /* a reference */
 391     case tcc_expression:  /* an expression */
 392     case tcc_statement:   /* an expression with side effects */
 393     case tcc_comparison:  /* a comparison expression */
 394     case tcc_unary:       /* a unary arithmetic expression */
 395     case tcc_binary:      /* a binary arithmetic expression */
 396       return (sizeof (struct tree_exp)
 397               + (TREE_CODE_LENGTH (code) - 1) * sizeof (char *));
 398
 399     case tcc_gimple_stmt:
 400       return (sizeof (struct gimple_stmt)
 401               + (TREE_CODE_LENGTH (code) - 1) * sizeof (char *));
 402
 403     case tcc_constant:  /* a constant */
 404       switch (code)
 405         {
 406         case INTEGER_CST:       return sizeof (struct tree_int_cst);
 407         case REAL_CST:          return sizeof (struct tree_real_cst);
 408         case COMPLEX_CST:       return sizeof (struct tree_complex);
 409         case VECTOR_CST:        return sizeof (struct tree_vector);
 410         case STRING_CST:        gcc_unreachable ();
 411         default:
 412           return lang_hooks.tree_size (code);
 413         }
 414
 415     case tcc_exceptional:  /* something random, like an identifier.  */
 416       switch (code)
 417         {
 418         case IDENTIFIER_NODE:   return lang_hooks.identifier_size;
 419         case TREE_LIST:         return sizeof (struct tree_list);
 420
 421         case ERROR_MARK:
 422         case PLACEHOLDER_EXPR:  return sizeof (struct tree_common);
 423
 424         case TREE_VEC:
 425         case OMP_CLAUSE:
 426         case PHI_NODE:          gcc_unreachable ();
 427
 428         case SSA_NAME:          return sizeof (struct tree_ssa_name);
 429
 430         case STATEMENT_LIST:    return sizeof (struct tree_statement_list);
 431         case BLOCK:             return sizeof (struct tree_block);
 432         case VALUE_HANDLE:      return sizeof (struct tree_value_handle);
 433         case CONSTRUCTOR:       return sizeof (struct tree_constructor);
 434
 435         default:
 436           return lang_hooks.tree_size (code);
 437         }
 438
 439     default:
 440       gcc_unreachable ();
 441     }
 442 }
 443
 444 /* Compute the number of bytes occupied by NODE.  This routine only
 445    looks at TREE_CODE, except for PHI_NODE and TREE_VEC nodes.  */
 446 size_t
 447 tree_size (tree node)
 448 {
 449   enum tree_code code = TREE_CODE (node);
 450   switch (code)
 451     {
 452     case PHI_NODE:
 453       return (sizeof (struct tree_phi_node)
 454               + (PHI_ARG_CAPACITY (node) - 1) * sizeof (struct phi_arg_d));
 455
 456     case TREE_BINFO:
 457       return (offsetof (struct tree_binfo, base_binfos)
 458               + VEC_embedded_size (tree, BINFO_N_BASE_BINFOS (node)));
 459
 460     case TREE_VEC:
 461       return (sizeof (struct tree_vec)
 462               + (TREE_VEC_LENGTH (node) - 1) * sizeof(char *));
 463
 464     case STRING_CST:
 465       return TREE_STRING_LENGTH (node) + offsetof (struct tree_string, str) + 1;
 466
 467     case OMP_CLAUSE:
 468       return (sizeof (struct tree_omp_clause)
 469               + (omp_clause_num_ops[OMP_CLAUSE_CODE (node)] - 1)
 470                 * sizeof (tree));
 471
 472     default:
 473       return tree_code_size (code);
 474     }
 475 }
 476
 477 /* Return a newly allocated node of code CODE.  For decl and type
 478    nodes, some other fields are initialized.  The rest of the node is
 479    initialized to zero.  This function cannot be used for PHI_NODE,
 480    TREE_VEC or OMP_CLAUSE nodes, which is enforced by asserts in
 481    tree_code_size.
 482
 483    Achoo!  I got a code in the node.  */
 484
 485 tree
 486 make_node_stat (enum tree_code code MEM_STAT_DECL)
 487 {
 488   tree t;
 489   enum tree_code_class type = TREE_CODE_CLASS (code);
 490   size_t length = tree_code_size (code);
 491 #ifdef GATHER_STATISTICS
 492   tree_node_kind kind;
 493
 494   switch (type)
 495     {
 496     case tcc_declaration:  /* A decl node */
 497       kind = d_kind;
 498       break;
 499
 500     case tcc_type:  /* a type node */
 501       kind = t_kind;
 502       break;
 503
 504     case tcc_statement:  /* an expression with side effects */
 505       kind = s_kind;
 506       break;
 507
 508     case tcc_reference:  /* a reference */
 509       kind = r_kind;
 510       break;
 511
 512     case tcc_expression:  /* an expression */
 513     case tcc_comparison:  /* a comparison expression */
 514     case tcc_unary:  /* a unary arithmetic expression */
 515     case tcc_binary:  /* a binary arithmetic expression */
 516       kind = e_kind;
 517       break;
 518
 519     case tcc_constant:  /* a constant */
 520       kind = c_kind;
 521       break;
 522
 523     case tcc_gimple_stmt:
 524       kind = gimple_stmt_kind;
 525       break;
 526
 527     case tcc_exceptional:  /* something random, like an identifier.  */
 528       switch (code)
 529         {
 530         case IDENTIFIER_NODE:
 531           kind = id_kind;
 532           break;
 533
 534         case TREE_VEC:
 535           kind = vec_kind;
 536           break;
 537
 538         case TREE_BINFO:
 539           kind = binfo_kind;
 540           break;
 541
 542         case PHI_NODE:
 543           kind = phi_kind;
 544           break;
 545
 546         case SSA_NAME:
 547           kind = ssa_name_kind;
 548           break;
 549
 550         case BLOCK:
 551           kind = b_kind;
 552           break;
 553
 554         case CONSTRUCTOR:
 555           kind = constr_kind;
 556           break;
 557
 558         default:
 559           kind = x_kind;
 560           break;
 561         }
 562       break;
 563
 564     default:
 565       gcc_unreachable ();
 566     }
 567
 568   tree_node_counts[(int) kind]++;
 569   tree_node_sizes[(int) kind] += length;
 570 #endif
 571
 572   if (code == IDENTIFIER_NODE)
 573     t = ggc_alloc_zone_pass_stat (length, &tree_id_zone);
 574   else
 575     t = ggc_alloc_zone_pass_stat (length, &tree_zone);
 576
 577   memset (t, 0, length);
 578
 579   TREE_SET_CODE (t, code);
 580
 581   switch (type)
 582     {
 583     case tcc_statement:
 584       TREE_SIDE_EFFECTS (t) = 1;
 585       break;
 586
 587     case tcc_declaration:
 588       if (CODE_CONTAINS_STRUCT (code, TS_DECL_WITH_VIS))
 589         DECL_IN_SYSTEM_HEADER (t) = in_system_header;
 590       if (CODE_CONTAINS_STRUCT (code, TS_DECL_COMMON))
 591         {
 592           if (code != FUNCTION_DECL)
 593             DECL_ALIGN (t) = 1;
 594           DECL_USER_ALIGN (t) = 0;
 595           /* We have not yet computed the alias set for this declaration.  */
 596           DECL_POINTER_ALIAS_SET (t) = -1;
 597         }
 598       DECL_SOURCE_LOCATION (t) = input_location;
 599       DECL_UID (t) = next_decl_uid++;
 600
 601       break;
 602
 603     case tcc_type:
 604       TYPE_UID (t) = next_type_uid++;
 605       TYPE_ALIGN (t) = BITS_PER_UNIT;
 606       TYPE_USER_ALIGN (t) = 0;
 607       TYPE_MAIN_VARIANT (t) = t;
 608       TYPE_CANONICAL (t) = t;
 609
 610       /* Default to no attributes for type, but let target change that.  */
 611       TYPE_ATTRIBUTES (t) = NULL_TREE;
 612       targetm.set_default_type_attributes (t);
 613
 614       /* We have not yet computed the alias set for this type.  */
 615       TYPE_ALIAS_SET (t) = -1;
 616       break;
 617
 618     case tcc_constant:
 619       TREE_CONSTANT (t) = 1;
 620       TREE_INVARIANT (t) = 1;
 621       break;
 622
 623     case tcc_expression:
 624       switch (code)
 625         {
 626         case INIT_EXPR:
 627         case MODIFY_EXPR:
 628         case VA_ARG_EXPR:
 629         case PREDECREMENT_EXPR:
 630         case PREINCREMENT_EXPR:
 631         case POSTDECREMENT_EXPR:
 632         case POSTINCREMENT_EXPR:
 633           /* All of these have side-effects, no matter what their
 634              operands are.  */
 635           TREE_SIDE_EFFECTS (t) = 1;
 636           break;
 637
 638         default:
 639           break;
 640         }
 641       break;
 642
 643     case tcc_gimple_stmt:
 644       switch (code)
 645         {
 646       case GIMPLE_MODIFY_STMT:
 647         TREE_SIDE_EFFECTS (t) = 1;
 648         break;
 649
 650       default:
 651         break;
 652         }
 653
 654     default:
 655       /* Other classes need no special treatment.  */
 656       break;
 657     }
 658
 659   return t;
 660 }
 661 \f
 662 /* Return a new node with the same contents as NODE except that its
 663    TREE_CHAIN is zero and it has a fresh uid.  */
 664
 665 tree
 666 copy_node_stat (tree node MEM_STAT_DECL)
 667 {
 668   tree t;
 669   enum tree_code code = TREE_CODE (node);
 670   size_t length;
 671
 672   gcc_assert (code != STATEMENT_LIST);
 673
 674   length = tree_size (node);
 675   t = ggc_alloc_zone_pass_stat (length, &tree_zone);
 676   memcpy (t, node, length);
 677
 678   if (!GIMPLE_TUPLE_P (node))
 679     TREE_CHAIN (t) = 0;
 680   TREE_ASM_WRITTEN (t) = 0;
 681   TREE_VISITED (t) = 0;
 682   t->base.ann = 0;
 683
 684   if (TREE_CODE_CLASS (code) == tcc_declaration)
 685     {
 686       DECL_UID (t) = next_decl_uid++;
 687       if ((TREE_CODE (node) == PARM_DECL || TREE_CODE (node) == VAR_DECL)
 688           && DECL_HAS_VALUE_EXPR_P (node))
 689         {
 690           SET_DECL_VALUE_EXPR (t, DECL_VALUE_EXPR (node));
 691           DECL_HAS_VALUE_EXPR_P (t) = 1;
 692         }
 693       if (TREE_CODE (node) == VAR_DECL && DECL_HAS_INIT_PRIORITY_P (node))
 694         {
 695           SET_DECL_INIT_PRIORITY (t, DECL_INIT_PRIORITY (node));
 696           DECL_HAS_INIT_PRIORITY_P (t) = 1;
 697         }
 698       if (TREE_CODE (node) == VAR_DECL && DECL_BASED_ON_RESTRICT_P (node))
 699         {
 700           SET_DECL_RESTRICT_BASE (t, DECL_GET_RESTRICT_BASE (node));
 701           DECL_BASED_ON_RESTRICT_P (t) = 1;
 702         }
 703     }
 704   else if (TREE_CODE_CLASS (code) == tcc_type)
 705     {
 706       TYPE_UID (t) = next_type_uid++;
 707       /* The following is so that the debug code for
 708          the copy is different from the original type.
 709          The two statements usually duplicate each other
 710          (because they clear fields of the same union),
 711          but the optimizer should catch that.  */
 712       TYPE_SYMTAB_POINTER (t) = 0;
 713       TYPE_SYMTAB_ADDRESS (t) = 0;
 714
 715       /* Do not copy the values cache.  */
 716       if (TYPE_CACHED_VALUES_P(t))
 717         {
 718           TYPE_CACHED_VALUES_P (t) = 0;
 719           TYPE_CACHED_VALUES (t) = NULL_TREE;
 720         }
 721     }
 722
 723   return t;
 724 }
 725
 726 /* Return a copy of a chain of nodes, chained through the TREE_CHAIN field.
 727    For example, this can copy a list made of TREE_LIST nodes.  */
 728
 729 tree
 730 copy_list (tree list)
 731 {
 732   tree head;
 733   tree prev, next;
 734
 735   if (list == 0)
 736     return 0;
 737
 738   head = prev = copy_node (list);
 739   next = TREE_CHAIN (list);
 740   while (next)
 741     {
 742       TREE_CHAIN (prev) = copy_node (next);
 743       prev = TREE_CHAIN (prev);
 744       next = TREE_CHAIN (next);
 745     }
 746   return head;
 747 }
 748
 749 \f
 750 /* Create an INT_CST node with a LOW value sign extended.  */
 751
 752 tree
 753 build_int_cst (tree type, HOST_WIDE_INT low)
 754 {
 755   /* Support legacy code.  */
 756   if (!type)
 757     type = integer_type_node;
 758
 759   return build_int_cst_wide (type, low, low < 0 ? -1 : 0);
 760 }
 761
 762 /* Create an INT_CST node with a LOW value zero extended.  */
 763
 764 tree
 765 build_int_cstu (tree type, unsigned HOST_WIDE_INT low)
 766 {
 767   return build_int_cst_wide (type, low, 0);
 768 }
 769
 770 /* Create an INT_CST node with a LOW value in TYPE.  The value is sign extended
 771    if it is negative.  This function is similar to build_int_cst, but
 772    the extra bits outside of the type precision are cleared.  Constants
 773    with these extra bits may confuse the fold so that it detects overflows
 774    even in cases when they do not occur, and in general should be avoided.
 775    We cannot however make this a default behavior of build_int_cst without
 776    more intrusive changes, since there are parts of gcc that rely on the extra
 777    precision of the integer constants.  */
 778
 779 tree
 780 build_int_cst_type (tree type, HOST_WIDE_INT low)
 781 {
 782   unsigned HOST_WIDE_INT low1;
 783   HOST_WIDE_INT hi;
 784
 785   gcc_assert (type);
 786
 787   fit_double_type (low, low < 0 ? -1 : 0, &low1, &hi, type);
 788
 789   return build_int_cst_wide (type, low1, hi);
 790 }
 791
 792 /* Create an INT_CST node of TYPE and value HI:LOW.  The value is truncated
 793    and sign extended according to the value range of TYPE.  */
 794
 795 tree
 796 build_int_cst_wide_type (tree type,
 797                          unsigned HOST_WIDE_INT low, HOST_WIDE_INT high)
 798 {
 799   fit_double_type (low, high, &low, &high, type);
 800   return build_int_cst_wide (type, low, high);
 801 }
 802
 803 /* These are the hash table functions for the hash table of INTEGER_CST
 804    nodes of a sizetype.  */
 805
 806 /* Return the hash code code X, an INTEGER_CST.  */
 807
 808 static hashval_t
 809 int_cst_hash_hash (const void *x)
 810 {
 811   tree t = (tree) x;
 812
 813   return (TREE_INT_CST_HIGH (t) ^ TREE_INT_CST_LOW (t)
 814           ^ htab_hash_pointer (TREE_TYPE (t)));
 815 }
 816
 817 /* Return nonzero if the value represented by *X (an INTEGER_CST tree node)
 818    is the same as that given by *Y, which is the same.  */
 819
 820 static int
 821 int_cst_hash_eq (const void *x, const void *y)
 822 {
 823   tree xt = (tree) x;
 824   tree yt = (tree) y;
 825
 826   return (TREE_TYPE (xt) == TREE_TYPE (yt)
 827           && TREE_INT_CST_HIGH (xt) == TREE_INT_CST_HIGH (yt)
 828           && TREE_INT_CST_LOW (xt) == TREE_INT_CST_LOW (yt));
 829 }
 830
 831 /* Create an INT_CST node of TYPE and value HI:LOW.
 832    The returned node is always shared.  For small integers we use a
 833    per-type vector cache, for larger ones we use a single hash table.  */
 834
 835 tree
 836 build_int_cst_wide (tree type, unsigned HOST_WIDE_INT low, HOST_WIDE_INT hi)
 837 {
 838   tree t;
 839   int ix = -1;
 840   int limit = 0;
 841
 842   gcc_assert (type);
 843
 844   switch (TREE_CODE (type))
 845     {
 846     case POINTER_TYPE:
 847     case REFERENCE_TYPE:
 848       /* Cache NULL pointer.  */
 849       if (!hi && !low)
 850         {
 851           limit = 1;
 852           ix = 0;
 853         }
 854       break;
 855
 856     case BOOLEAN_TYPE:
 857       /* Cache false or true.  */
 858       limit = 2;
 859       if (!hi && low < 2)
 860         ix = low;
 861       break;
 862
 863     case INTEGER_TYPE:
 864     case OFFSET_TYPE:
 865       if (TYPE_UNSIGNED (type))
 866         {
 867           /* Cache 0..N */
 868           limit = INTEGER_SHARE_LIMIT;
 869           if (!hi && low < (unsigned HOST_WIDE_INT)INTEGER_SHARE_LIMIT)
 870             ix = low;
 871         }
 872       else
 873         {
 874           /* Cache -1..N */
 875           limit = INTEGER_SHARE_LIMIT + 1;
 876           if (!hi && low < (unsigned HOST_WIDE_INT)INTEGER_SHARE_LIMIT)
 877             ix = low + 1;
 878           else if (hi == -1 && low == -(unsigned HOST_WIDE_INT)1)
 879             ix = 0;
 880         }
 881       break;
 882
 883     case ENUMERAL_TYPE:
 884       break;
 885
 886     default:
 887       gcc_unreachable ();
 888     }
 889
 890   if (ix >= 0)
 891     {
 892       /* Look for it in the type's vector of small shared ints.  */
 893       if (!TYPE_CACHED_VALUES_P (type))
 894         {
 895           TYPE_CACHED_VALUES_P (type) = 1;
 896           TYPE_CACHED_VALUES (type) = make_tree_vec (limit);
 897         }
 898
 899       t = TREE_VEC_ELT (TYPE_CACHED_VALUES (type), ix);
 900       if (t)
 901         {
 902           /* Make sure no one is clobbering the shared constant.  */
 903           gcc_assert (TREE_TYPE (t) == type);
 904           gcc_assert (TREE_INT_CST_LOW (t) == low);
 905           gcc_assert (TREE_INT_CST_HIGH (t) == hi);
 906         }
 907       else
 908         {
 909           /* Create a new shared int.  */
 910           t = make_node (INTEGER_CST);
 911
 912           TREE_INT_CST_LOW (t) = low;
 913           TREE_INT_CST_HIGH (t) = hi;
 914           TREE_TYPE (t) = type;
 915
 916           TREE_VEC_ELT (TYPE_CACHED_VALUES (type), ix) = t;
 917         }
 918     }
 919   else
 920     {
 921       /* Use the cache of larger shared ints.  */
 922       void **slot;
 923
 924       TREE_INT_CST_LOW (int_cst_node) = low;
 925       TREE_INT_CST_HIGH (int_cst_node) = hi;
 926       TREE_TYPE (int_cst_node) = type;
 927
 928       slot = htab_find_slot (int_cst_hash_table, int_cst_node, INSERT);
 929       t = *slot;
 930       if (!t)
 931         {
 932           /* Insert this one into the hash table.  */
 933           t = int_cst_node;
 934           *slot = t;
 935           /* Make a new node for next time round.  */
 936           int_cst_node = make_node (INTEGER_CST);
 937         }
 938     }
 939
 940   return t;
 941 }
 942
 943 /* Builds an integer constant in TYPE such that lowest BITS bits are ones
 944    and the rest are zeros.  */
 945
 946 tree
 947 build_low_bits_mask (tree type, unsigned bits)
 948 {
 949   unsigned HOST_WIDE_INT low;
 950   HOST_WIDE_INT high;
 951   unsigned HOST_WIDE_INT all_ones = ~(unsigned HOST_WIDE_INT) 0;
 952
 953   gcc_assert (bits <= TYPE_PRECISION (type));
 954
 955   if (bits == TYPE_PRECISION (type)
 956       && !TYPE_UNSIGNED (type))
 957     {
 958       /* Sign extended all-ones mask.  */
 959       low = all_ones;
 960       high = -1;
 961     }
 962   else if (bits <= HOST_BITS_PER_WIDE_INT)
 963     {
 964       low = all_ones >> (HOST_BITS_PER_WIDE_INT - bits);
 965       high = 0;
 966     }
 967   else
 968     {
 969       bits -= HOST_BITS_PER_WIDE_INT;
 970       low = all_ones;
 971       high = all_ones >> (HOST_BITS_PER_WIDE_INT - bits);
 972     }
 973
 974   return build_int_cst_wide (type, low, high);
 975 }
 976
 977 /* Checks that X is integer constant that can be expressed in (unsigned)
 978    HOST_WIDE_INT without loss of precision.  */
 979
 980 bool
 981 cst_and_fits_in_hwi (tree x)
 982 {
 983   if (TREE_CODE (x) != INTEGER_CST)
 984     return false;
 985
 986   if (TYPE_PRECISION (TREE_TYPE (x)) > HOST_BITS_PER_WIDE_INT)
 987     return false;
 988
 989   return (TREE_INT_CST_HIGH (x) == 0
 990           || TREE_INT_CST_HIGH (x) == -1);
 991 }
 992
 993 /* Return a new VECTOR_CST node whose type is TYPE and whose values
 994    are in a list pointed to by VALS.  */
 995
 996 tree
 997 build_vector (tree type, tree vals)
 998 {
 999   tree v = make_node (VECTOR_CST);
1000   int over = 0;
1001   tree link;
1002
1003   TREE_VECTOR_CST_ELTS (v) = vals;
1004   TREE_TYPE (v) = type;
1005
1006   /* Iterate through elements and check for overflow.  */
1007   for (link = vals; link; link = TREE_CHAIN (link))
1008     {
1009       tree value = TREE_VALUE (link);
1010
1011       /* Don't crash if we get an address constant.  */
1012       if (!CONSTANT_CLASS_P (value))
1013         continue;
1014
1015       over |= TREE_OVERFLOW (value);
1016     }
1017
1018   TREE_OVERFLOW (v) = over;
1019   return v;
1020 }
1021
1022 /* Return a new VECTOR_CST node whose type is TYPE and whose values
1023    are extracted from V, a vector of CONSTRUCTOR_ELT.  */
1024
1025 tree
1026 build_vector_from_ctor (tree type, VEC(constructor_elt,gc) *v)
1027 {
1028   tree list = NULL_TREE;
1029   unsigned HOST_WIDE_INT idx;
1030   tree value;
1031
1032   FOR_EACH_CONSTRUCTOR_VALUE (v, idx, value)
1033     list = tree_cons (NULL_TREE, value, list);
1034   return build_vector (type, nreverse (list));
1035 }
1036
1037 /* Return a new CONSTRUCTOR node whose type is TYPE and whose values
1038    are in the VEC pointed to by VALS.  */
1039 tree
1040 build_constructor (tree type, VEC(constructor_elt,gc) *vals)
1041 {
1042   tree c = make_node (CONSTRUCTOR);
1043   TREE_TYPE (c) = type;
1044   CONSTRUCTOR_ELTS (c) = vals;
1045   return c;
1046 }
1047
1048 /* Build a CONSTRUCTOR node made of a single initializer, with the specified
1049    INDEX and VALUE.  */
1050 tree
1051 build_constructor_single (tree type, tree index, tree value)
1052 {
1053   VEC(constructor_elt,gc) *v;
1054   constructor_elt *elt;
1055   tree t;
1056
1057   v = VEC_alloc (constructor_elt, gc, 1);
1058   elt = VEC_quick_push (constructor_elt, v, NULL);
1059   elt->index = index;
1060   elt->value = value;
1061
1062   t = build_constructor (type, v);
1063   TREE_CONSTANT (t) = TREE_CONSTANT (value);
1064   return t;
1065 }
1066
1067
1068 /* Return a new CONSTRUCTOR node whose type is TYPE and whose values
1069    are in a list pointed to by VALS.  */
1070 tree
1071 build_constructor_from_list (tree type, tree vals)
1072 {
1073   tree t, val;
1074   VEC(constructor_elt,gc) *v = NULL;
1075   bool constant_p = true;
1076
1077   if (vals)
1078     {
1079       v = VEC_alloc (constructor_elt, gc, list_length (vals));
1080       for (t = vals; t; t = TREE_CHAIN (t))
1081         {
1082           constructor_elt *elt = VEC_quick_push (constructor_elt, v, NULL);
1083           val = TREE_VALUE (t);
1084           elt->index = TREE_PURPOSE (t);
1085           elt->value = val;
1086           if (!TREE_CONSTANT (val))
1087             constant_p = false;
1088         }
1089     }
1090
1091   t = build_constructor (type, v);
1092   TREE_CONSTANT (t) = constant_p;
1093   return t;
1094 }
1095
1096
1097 /* Return a new REAL_CST node whose type is TYPE and value is D.  */
1098
1099 tree
1100 build_real (tree type, REAL_VALUE_TYPE d)
1101 {
1102   tree v;
1103   REAL_VALUE_TYPE *dp;
1104   int overflow = 0;
1105
1106   /* ??? Used to check for overflow here via CHECK_FLOAT_TYPE.
1107      Consider doing it via real_convert now.  */
1108
1109   v = make_node (REAL_CST);
1110   dp = ggc_alloc (sizeof (REAL_VALUE_TYPE));
1111   memcpy (dp, &d, sizeof (REAL_VALUE_TYPE));
1112
1113   TREE_TYPE (v) = type;
1114   TREE_REAL_CST_PTR (v) = dp;
1115   TREE_OVERFLOW (v) = overflow;
1116   return v;
1117 }
1118
1119 /* Return a new REAL_CST node whose type is TYPE
1120    and whose value is the integer value of the INTEGER_CST node I.  */
1121
1122 REAL_VALUE_TYPE
1123 real_value_from_int_cst (tree type, tree i)
1124 {
1125   REAL_VALUE_TYPE d;
1126
1127   /* Clear all bits of the real value type so that we can later do
1128      bitwise comparisons to see if two values are the same.  */
1129   memset (&d, 0, sizeof d);
1130
1131   real_from_integer (&d, type ? TYPE_MODE (type) : VOIDmode,
1132                      TREE_INT_CST_LOW (i), TREE_INT_CST_HIGH (i),
1133                      TYPE_UNSIGNED (TREE_TYPE (i)));
1134   return d;
1135 }
1136
1137 /* Given a tree representing an integer constant I, return a tree
1138    representing the same value as a floating-point constant of type TYPE.  */
1139
1140 tree
1141 build_real_from_int_cst (tree type, tree i)
1142 {
1143   tree v;
1144   int overflow = TREE_OVERFLOW (i);
1145
1146   v = build_real (type, real_value_from_int_cst (type, i));
1147
1148   TREE_OVERFLOW (v) |= overflow;
1149   return v;
1150 }
1151
1152 /* Return a newly constructed STRING_CST node whose value is
1153    the LEN characters at STR.
1154    The TREE_TYPE is not initialized.  */
1155
1156 tree
1157 build_string (int len, const char *str)
1158 {
1159   tree s;
1160   size_t length;
1161
1162   /* Do not waste bytes provided by padding of struct tree_string.  */
1163   length = len + offsetof (struct tree_string, str) + 1;
1164
1165 #ifdef GATHER_STATISTICS
1166   tree_node_counts[(int) c_kind]++;
1167   tree_node_sizes[(int) c_kind] += length;
1168 #endif
1169
1170   s = ggc_alloc_tree (length);
1171
1172   memset (s, 0, sizeof (struct tree_common));
1173   TREE_SET_CODE (s, STRING_CST);
1174   TREE_CONSTANT (s) = 1;
1175   TREE_INVARIANT (s) = 1;
1176   TREE_STRING_LENGTH (s) = len;
1177   memcpy ((char *) TREE_STRING_POINTER (s), str, len);
1178   ((char *) TREE_STRING_POINTER (s))[len] = '\0';
1179
1180   return s;
1181 }
1182
1183 /* Return a newly constructed COMPLEX_CST node whose value is
1184    specified by the real and imaginary parts REAL and IMAG.
1185    Both REAL and IMAG should be constant nodes.  TYPE, if specified,
1186    will be the type of the COMPLEX_CST; otherwise a new type will be made.  */
1187
1188 tree
1189 build_complex (tree type, tree real, tree imag)
1190 {
1191   tree t = make_node (COMPLEX_CST);
1192
1193   TREE_REALPART (t) = real;
1194   TREE_IMAGPART (t) = imag;
1195   TREE_TYPE (t) = type ? type : build_complex_type (TREE_TYPE (real));
1196   TREE_OVERFLOW (t) = TREE_OVERFLOW (real) | TREE_OVERFLOW (imag);
1197   return t;
1198 }
1199
1200 /* Return a constant of arithmetic type TYPE which is the
1201    multiplicative identity of the set TYPE.  */
1202
1203 tree
1204 build_one_cst (tree type)
1205 {
1206   switch (TREE_CODE (type))
1207     {
1208     case INTEGER_TYPE: case ENUMERAL_TYPE: case BOOLEAN_TYPE:
1209     case POINTER_TYPE: case REFERENCE_TYPE:
1210     case OFFSET_TYPE:
1211       return build_int_cst (type, 1);
1212
1213     case REAL_TYPE:
1214       return build_real (type, dconst1);
1215
1216     case VECTOR_TYPE:
1217       {
1218         tree scalar, cst;
1219         int i;
1220
1221         scalar = build_one_cst (TREE_TYPE (type));
1222
1223         /* Create 'vect_cst_ = {cst,cst,...,cst}'  */
1224         cst = NULL_TREE;
1225         for (i = TYPE_VECTOR_SUBPARTS (type); --i >= 0; )
1226           cst = tree_cons (NULL_TREE, scalar, cst);
1227
1228         return build_vector (type, cst);
1229       }
1230
1231     case COMPLEX_TYPE:
1232       return build_complex (type,
1233                             build_one_cst (TREE_TYPE (type)),
1234                             fold_convert (TREE_TYPE (type), integer_zero_node));
1235
1236     default:
1237       gcc_unreachable ();
1238     }
1239 }
1240
1241 /* Build a BINFO with LEN language slots.  */
1242
1243 tree
1244 make_tree_binfo_stat (unsigned base_binfos MEM_STAT_DECL)
1245 {
1246   tree t;
1247   size_t length = (offsetof (struct tree_binfo, base_binfos)
1248                    + VEC_embedded_size (tree, base_binfos));
1249
1250 #ifdef GATHER_STATISTICS
1251   tree_node_counts[(int) binfo_kind]++;
1252   tree_node_sizes[(int) binfo_kind] += length;
1253 #endif
1254
1255   t = ggc_alloc_zone_pass_stat (length, &tree_zone);
1256
1257   memset (t, 0, offsetof (struct tree_binfo, base_binfos));
1258
1259   TREE_SET_CODE (t, TREE_BINFO);
1260
1261   VEC_embedded_init (tree, BINFO_BASE_BINFOS (t), base_binfos);
1262
1263   return t;
1264 }
1265
1266
1267 /* Build a newly constructed TREE_VEC node of length LEN.  */
1268
1269 tree
1270 make_tree_vec_stat (int len MEM_STAT_DECL)
1271 {
1272   tree t;
1273   int length = (len - 1) * sizeof (tree) + sizeof (struct tree_vec);
1274
1275 #ifdef GATHER_STATISTICS
1276   tree_node_counts[(int) vec_kind]++;
1277   tree_node_sizes[(int) vec_kind] += length;
1278 #endif
1279
1280   t = ggc_alloc_zone_pass_stat (length, &tree_zone);
1281
1282   memset (t, 0, length);
1283
1284   TREE_SET_CODE (t, TREE_VEC);
1285   TREE_VEC_LENGTH (t) = len;
1286
1287   return t;
1288 }
1289 \f
1290 /* Return 1 if EXPR is the integer constant zero or a complex constant
1291    of zero.  */
1292
1293 int
1294 integer_zerop (tree expr)
1295 {
1296   STRIP_NOPS (expr);
1297
1298   return ((TREE_CODE (expr) == INTEGER_CST
1299            && TREE_INT_CST_LOW (expr) == 0
1300            && TREE_INT_CST_HIGH (expr) == 0)
1301           || (TREE_CODE (expr) == COMPLEX_CST
1302               && integer_zerop (TREE_REALPART (expr))
1303               && integer_zerop (TREE_IMAGPART (expr))));
1304 }
1305
1306 /* Return 1 if EXPR is the integer constant one or the corresponding
1307    complex constant.  */
1308
1309 int
1310 integer_onep (tree expr)
1311 {
1312   STRIP_NOPS (expr);
1313
1314   return ((TREE_CODE (expr) == INTEGER_CST
1315            && TREE_INT_CST_LOW (expr) == 1
1316            && TREE_INT_CST_HIGH (expr) == 0)
1317           || (TREE_CODE (expr) == COMPLEX_CST
1318               && integer_onep (TREE_REALPART (expr))
1319               && integer_zerop (TREE_IMAGPART (expr))));
1320 }
1321
1322 /* Return 1 if EXPR is an integer containing all 1's in as much precision as
1323    it contains.  Likewise for the corresponding complex constant.  */
1324
1325 int
1326 integer_all_onesp (tree expr)
1327 {
1328   int prec;
1329   int uns;
1330
1331   STRIP_NOPS (expr);
1332
1333   if (TREE_CODE (expr) == COMPLEX_CST
1334       && integer_all_onesp (TREE_REALPART (expr))
1335       && integer_zerop (TREE_IMAGPART (expr)))
1336     return 1;
1337
1338   else if (TREE_CODE (expr) != INTEGER_CST)
1339     return 0;
1340
1341   uns = TYPE_UNSIGNED (TREE_TYPE (expr));
1342   if (TREE_INT_CST_LOW (expr) == ~(unsigned HOST_WIDE_INT) 0
1343       && TREE_INT_CST_HIGH (expr) == -1)
1344     return 1;
1345   if (!uns)
1346     return 0;
1347
1348   /* Note that using TYPE_PRECISION here is wrong.  We care about the
1349      actual bits, not the (arbitrary) range of the type.  */
1350   prec = GET_MODE_BITSIZE (TYPE_MODE (TREE_TYPE (expr)));
1351   if (prec >= HOST_BITS_PER_WIDE_INT)
1352     {
1353       HOST_WIDE_INT high_value;
1354       int shift_amount;
1355
1356       shift_amount = prec - HOST_BITS_PER_WIDE_INT;
1357
1358       /* Can not handle precisions greater than twice the host int size.  */
1359       gcc_assert (shift_amount <= HOST_BITS_PER_WIDE_INT);
1360       if (shift_amount == HOST_BITS_PER_WIDE_INT)
1361         /* Shifting by the host word size is undefined according to the ANSI
1362            standard, so we must handle this as a special case.  */
1363         high_value = -1;
1364       else
1365         high_value = ((HOST_WIDE_INT) 1 << shift_amount) - 1;
1366
1367       return (TREE_INT_CST_LOW (expr) == ~(unsigned HOST_WIDE_INT) 0
1368               && TREE_INT_CST_HIGH (expr) == high_value);
1369     }
1370   else
1371     return TREE_INT_CST_LOW (expr) == ((unsigned HOST_WIDE_INT) 1 << prec) - 1;
1372 }
1373
1374 /* Return 1 if EXPR is an integer constant that is a power of 2 (i.e., has only
1375    one bit on).  */
1376
1377 int
1378 integer_pow2p (tree expr)
1379 {
1380   int prec;
1381   HOST_WIDE_INT high, low;
1382
1383   STRIP_NOPS (expr);
1384
1385   if (TREE_CODE (expr) == COMPLEX_CST
1386       && integer_pow2p (TREE_REALPART (expr))
1387       && integer_zerop (TREE_IMAGPART (expr)))
1388     return 1;
1389
1390   if (TREE_CODE (expr) != INTEGER_CST)
1391     return 0;
1392
1393   prec = (POINTER_TYPE_P (TREE_TYPE (expr))
1394           ? POINTER_SIZE : TYPE_PRECISION (TREE_TYPE (expr)));
1395   high = TREE_INT_CST_HIGH (expr);
1396   low = TREE_INT_CST_LOW (expr);
1397
1398   /* First clear all bits that are beyond the type's precision in case
1399      we've been sign extended.  */
1400
1401   if (prec == 2 * HOST_BITS_PER_WIDE_INT)
1402     ;
1403   else if (prec > HOST_BITS_PER_WIDE_INT)
1404     high &= ~((HOST_WIDE_INT) (-1) << (prec - HOST_BITS_PER_WIDE_INT));
1405   else
1406     {
1407       high = 0;
1408       if (prec < HOST_BITS_PER_WIDE_INT)
1409         low &= ~((HOST_WIDE_INT) (-1) << prec);
1410     }
1411
1412   if (high == 0 && low == 0)
1413     return 0;
1414
1415   return ((high == 0 && (low & (low - 1)) == 0)
1416           || (low == 0 && (high & (high - 1)) == 0));
1417 }
1418
1419 /* Return 1 if EXPR is an integer constant other than zero or a
1420    complex constant other than zero.  */
1421
1422 int
1423 integer_nonzerop (tree expr)
1424 {
1425   STRIP_NOPS (expr);
1426
1427   return ((TREE_CODE (expr) == INTEGER_CST
1428            && (TREE_INT_CST_LOW (expr) != 0
1429                || TREE_INT_CST_HIGH (expr) != 0))
1430           || (TREE_CODE (expr) == COMPLEX_CST
1431               && (integer_nonzerop (TREE_REALPART (expr))
1432                   || integer_nonzerop (TREE_IMAGPART (expr)))));
1433 }
1434
1435 /* Return the power of two represented by a tree node known to be a
1436    power of two.  */
1437
1438 int
1439 tree_log2 (tree expr)
1440 {
1441   int prec;
1442   HOST_WIDE_INT high, low;
1443
1444   STRIP_NOPS (expr);
1445
1446   if (TREE_CODE (expr) == COMPLEX_CST)
1447     return tree_log2 (TREE_REALPART (expr));
1448
1449   prec = (POINTER_TYPE_P (TREE_TYPE (expr))
1450           ? POINTER_SIZE : TYPE_PRECISION (TREE_TYPE (expr)));
1451
1452   high = TREE_INT_CST_HIGH (expr);
1453   low = TREE_INT_CST_LOW (expr);
1454
1455   /* First clear all bits that are beyond the type's precision in case
1456      we've been sign extended.  */
1457
1458   if (prec == 2 * HOST_BITS_PER_WIDE_INT)
1459     ;
1460   else if (prec > HOST_BITS_PER_WIDE_INT)
1461     high &= ~((HOST_WIDE_INT) (-1) << (prec - HOST_BITS_PER_WIDE_INT));
1462   else
1463     {
1464       high = 0;
1465       if (prec < HOST_BITS_PER_WIDE_INT)
1466         low &= ~((HOST_WIDE_INT) (-1) << prec);
1467     }
1468
1469   return (high != 0 ? HOST_BITS_PER_WIDE_INT + exact_log2 (high)
1470           : exact_log2 (low));
1471 }
1472
1473 /* Similar, but return the largest integer Y such that 2 ** Y is less
1474    than or equal to EXPR.  */
1475
1476 int
1477 tree_floor_log2 (tree expr)
1478 {
1479   int prec;
1480   HOST_WIDE_INT high, low;
1481
1482   STRIP_NOPS (expr);
1483
1484   if (TREE_CODE (expr) == COMPLEX_CST)
1485     return tree_log2 (TREE_REALPART (expr));
1486
1487   prec = (POINTER_TYPE_P (TREE_TYPE (expr))
1488           ? POINTER_SIZE : TYPE_PRECISION (TREE_TYPE (expr)));
1489
1490   high = TREE_INT_CST_HIGH (expr);
1491   low = TREE_INT_CST_LOW (expr);
1492
1493   /* First clear all bits that are beyond the type's precision in case
1494      we've been sign extended.  Ignore if type's precision hasn't been set
1495      since what we are doing is setting it.  */
1496
1497   if (prec == 2 * HOST_BITS_PER_WIDE_INT || prec == 0)
1498     ;
1499   else if (prec > HOST_BITS_PER_WIDE_INT)
1500     high &= ~((HOST_WIDE_INT) (-1) << (prec - HOST_BITS_PER_WIDE_INT));
1501   else
1502     {
1503       high = 0;
1504       if (prec < HOST_BITS_PER_WIDE_INT)
1505         low &= ~((HOST_WIDE_INT) (-1) << prec);
1506     }
1507
1508   return (high != 0 ? HOST_BITS_PER_WIDE_INT + floor_log2 (high)
1509           : floor_log2 (low));
1510 }
1511
1512 /* Return 1 if EXPR is the real constant zero.  */
1513
1514 int
1515 real_zerop (tree expr)
1516 {
1517   STRIP_NOPS (expr);
1518
1519   return ((TREE_CODE (expr) == REAL_CST
1520            && REAL_VALUES_EQUAL (TREE_REAL_CST (expr), dconst0))
1521           || (TREE_CODE (expr) == COMPLEX_CST
1522               && real_zerop (TREE_REALPART (expr))
1523               && real_zerop (TREE_IMAGPART (expr))));
1524 }
1525
1526 /* Return 1 if EXPR is the real constant one in real or complex form.  */
1527
1528 int
1529 real_onep (tree expr)
1530 {
1531   STRIP_NOPS (expr);
1532
1533   return ((TREE_CODE (expr) == REAL_CST
1534            && REAL_VALUES_EQUAL (TREE_REAL_CST (expr), dconst1))
1535           || (TREE_CODE (expr) == COMPLEX_CST
1536               && real_onep (TREE_REALPART (expr))
1537               && real_zerop (TREE_IMAGPART (expr))));
1538 }
1539
1540 /* Return 1 if EXPR is the real constant two.  */
1541
1542 int
1543 real_twop (tree expr)
1544 {
1545   STRIP_NOPS (expr);
1546
1547   return ((TREE_CODE (expr) == REAL_CST
1548            && REAL_VALUES_EQUAL (TREE_REAL_CST (expr), dconst2))
1549           || (TREE_CODE (expr) == COMPLEX_CST
1550               && real_twop (TREE_REALPART (expr))
1551               && real_zerop (TREE_IMAGPART (expr))));
1552 }
1553
1554 /* Return 1 if EXPR is the real constant minus one.  */
1555
1556 int
1557 real_minus_onep (tree expr)
1558 {
1559   STRIP_NOPS (expr);
1560
1561   return ((TREE_CODE (expr) == REAL_CST
1562            && REAL_VALUES_EQUAL (TREE_REAL_CST (expr), dconstm1))
1563           || (TREE_CODE (expr) == COMPLEX_CST
1564               && real_minus_onep (TREE_REALPART (expr))
1565               && real_zerop (TREE_IMAGPART (expr))));
1566 }
1567
1568 /* Nonzero if EXP is a constant or a cast of a constant.  */
1569
1570 int
1571 really_constant_p (tree exp)
1572 {
1573   /* This is not quite the same as STRIP_NOPS.  It does more.  */
1574   while (TREE_CODE (exp) == NOP_EXPR
1575          || TREE_CODE (exp) == CONVERT_EXPR
1576          || TREE_CODE (exp) == NON_LVALUE_EXPR)
1577     exp = TREE_OPERAND (exp, 0);
1578   return TREE_CONSTANT (exp);
1579 }
1580 \f
1581 /* Return first list element whose TREE_VALUE is ELEM.
1582    Return 0 if ELEM is not in LIST.  */
1583
1584 tree
1585 value_member (tree elem, tree list)
1586 {
1587   while (list)
1588     {
1589       if (elem == TREE_VALUE (list))
1590         return list;
1591       list = TREE_CHAIN (list);
1592     }
1593   return NULL_TREE;
1594 }
1595
1596 /* Return first list element whose TREE_PURPOSE is ELEM.
1597    Return 0 if ELEM is not in LIST.  */
1598
1599 tree
1600 purpose_member (tree elem, tree list)
1601 {
1602   while (list)
1603     {
1604       if (elem == TREE_PURPOSE (list))
1605         return list;
1606       list = TREE_CHAIN (list);
1607     }
1608   return NULL_TREE;
1609 }
1610
1611 /* Return nonzero if ELEM is part of the chain CHAIN.  */
1612
1613 int
1614 chain_member (tree elem, tree chain)
1615 {
1616   while (chain)
1617     {
1618       if (elem == chain)
1619         return 1;
1620       chain = TREE_CHAIN (chain);
1621     }
1622
1623   return 0;
1624 }
1625
1626 /* Return the length of a chain of nodes chained through TREE_CHAIN.
1627    We expect a null pointer to mark the end of the chain.
1628    This is the Lisp primitive `length'.  */
1629
1630 int
1631 list_length (tree t)
1632 {
1633   tree p = t;
1634 #ifdef ENABLE_TREE_CHECKING
1635   tree q = t;
1636 #endif
1637   int len = 0;
1638
1639   while (p)
1640     {
1641       p = TREE_CHAIN (p);
1642 #ifdef ENABLE_TREE_CHECKING
1643       if (len % 2)
1644         q = TREE_CHAIN (q);
1645       gcc_assert (p != q);
1646 #endif
1647       len++;
1648     }
1649
1650   return len;
1651 }
1652
1653 /* Returns the number of FIELD_DECLs in TYPE.  */
1654
1655 int
1656 fields_length (tree type)
1657 {
1658   tree t = TYPE_FIELDS (type);
1659   int count = 0;
1660
1661   for (; t; t = TREE_CHAIN (t))
1662     if (TREE_CODE (t) == FIELD_DECL)
1663       ++count;
1664
1665   return count;
1666 }
1667
1668 /* Concatenate two chains of nodes (chained through TREE_CHAIN)
1669    by modifying the last node in chain 1 to point to chain 2.
1670    This is the Lisp primitive `nconc'.  */
1671
1672 tree
1673 chainon (tree op1, tree op2)
1674 {
1675   tree t1;
1676
1677   if (!op1)
1678     return op2;
1679   if (!op2)
1680     return op1;
1681
1682   for (t1 = op1; TREE_CHAIN (t1); t1 = TREE_CHAIN (t1))
1683     continue;
1684   TREE_CHAIN (t1) = op2;
1685
1686 #ifdef ENABLE_TREE_CHECKING
1687   {
1688     tree t2;
1689     for (t2 = op2; t2; t2 = TREE_CHAIN (t2))
1690       gcc_assert (t2 != t1);
1691   }
1692 #endif
1693
1694   return op1;
1695 }
1696
1697 /* Return the last node in a chain of nodes (chained through TREE_CHAIN).  */
1698
1699 tree
1700 tree_last (tree chain)
1701 {
1702   tree next;
1703   if (chain)
1704     while ((next = TREE_CHAIN (chain)))
1705       chain = next;
1706   return chain;
1707 }
1708
1709 /* Reverse the order of elements in the chain T,
1710    and return the new head of the chain (old last element).  */
1711
1712 tree
1713 nreverse (tree t)
1714 {
1715   tree prev = 0, decl, next;
1716   for (decl = t; decl; decl = next)
1717     {
1718       next = TREE_CHAIN (decl);
1719       TREE_CHAIN (decl) = prev;
1720       prev = decl;
1721     }
1722   return prev;
1723 }
1724 \f
1725 /* Return a newly created TREE_LIST node whose
1726    purpose and value fields are PARM and VALUE.  */
1727
1728 tree
1729 build_tree_list_stat (tree parm, tree value MEM_STAT_DECL)
1730 {
1731   tree t = make_node_stat (TREE_LIST PASS_MEM_STAT);
1732   TREE_PURPOSE (t) = parm;
1733   TREE_VALUE (t) = value;
1734   return t;
1735 }
1736
1737 /* Return a newly created TREE_LIST node whose
1738    purpose and value fields are PURPOSE and VALUE
1739    and whose TREE_CHAIN is CHAIN.  */
1740
1741 tree
1742 tree_cons_stat (tree purpose, tree value, tree chain MEM_STAT_DECL)
1743 {
1744   tree node;
1745
1746   node = ggc_alloc_zone_pass_stat (sizeof (struct tree_list), &tree_zone);
1747
1748   memset (node, 0, sizeof (struct tree_common));
1749
1750 #ifdef GATHER_STATISTICS
1751   tree_node_counts[(int) x_kind]++;
1752   tree_node_sizes[(int) x_kind] += sizeof (struct tree_list);
1753 #endif
1754
1755   TREE_SET_CODE (node, TREE_LIST);
1756   TREE_CHAIN (node) = chain;
1757   TREE_PURPOSE (node) = purpose;
1758   TREE_VALUE (node) = value;
1759   return node;
1760 }
1761
1762 \f
1763 /* Return the size nominally occupied by an object of type TYPE
1764    when it resides in memory.  The value is measured in units of bytes,
1765    and its data type is that normally used for type sizes
1766    (which is the first type created by make_signed_type or
1767    make_unsigned_type).  */
1768
1769 tree
1770 size_in_bytes (tree type)
1771 {
1772   tree t;
1773
1774   if (type == error_mark_node)
1775     return integer_zero_node;
1776
1777   type = TYPE_MAIN_VARIANT (type);
1778   t = TYPE_SIZE_UNIT (type);
1779
1780   if (t == 0)
1781     {
1782       lang_hooks.types.incomplete_type_error (NULL_TREE, type);
1783       return size_zero_node;
1784     }
1785
1786   return t;
1787 }
1788
1789 /* Return the size of TYPE (in bytes) as a wide integer
1790    or return -1 if the size can vary or is larger than an integer.  */
1791
1792 HOST_WIDE_INT
1793 int_size_in_bytes (tree type)
1794 {
1795   tree t;
1796
1797   if (type == error_mark_node)
1798     return 0;
1799
1800   type = TYPE_MAIN_VARIANT (type);
1801   t = TYPE_SIZE_UNIT (type);
1802   if (t == 0
1803       || TREE_CODE (t) != INTEGER_CST
1804       || TREE_INT_CST_HIGH (t) != 0
1805       /* If the result would appear negative, it's too big to represent.  */
1806       || (HOST_WIDE_INT) TREE_INT_CST_LOW (t) < 0)
1807     return -1;
1808
1809   return TREE_INT_CST_LOW (t);
1810 }
1811
1812 /* Return the maximum size of TYPE (in bytes) as a wide integer
1813    or return -1 if the size can vary or is larger than an integer.  */
1814
1815 HOST_WIDE_INT
1816 max_int_size_in_bytes (tree type)
1817 {
1818   HOST_WIDE_INT size = -1;
1819   tree size_tree;
1820
1821   /* If this is an array type, check for a possible MAX_SIZE attached.  */
1822
1823   if (TREE_CODE (type) == ARRAY_TYPE)
1824     {
1825       size_tree = TYPE_ARRAY_MAX_SIZE (type);
1826
1827       if (size_tree && host_integerp (size_tree, 1))
1828         size = tree_low_cst (size_tree, 1);
1829     }
1830
1831   /* If we still haven't been able to get a size, see if the language
1832      can compute a maximum size.  */
1833
1834   if (size == -1)
1835     {
1836       size_tree = lang_hooks.types.max_size (type);
1837
1838       if (size_tree && host_integerp (size_tree, 1))
1839         size = tree_low_cst (size_tree, 1);
1840     }
1841
1842   return size;
1843 }
1844 \f
1845 /* Return the bit position of FIELD, in bits from the start of the record.
1846    This is a tree of type bitsizetype.  */
1847
1848 tree
1849 bit_position (tree field)
1850 {
1851   return bit_from_pos (DECL_FIELD_OFFSET (field),
1852                        DECL_FIELD_BIT_OFFSET (field));
1853 }
1854
1855 /* Likewise, but return as an integer.  It must be representable in
1856    that way (since it could be a signed value, we don't have the
1857    option of returning -1 like int_size_in_byte can.  */
1858
1859 HOST_WIDE_INT
1860 int_bit_position (tree field)
1861 {
1862   return tree_low_cst (bit_position (field), 0);
1863 }
1864 \f
1865 /* Return the byte position of FIELD, in bytes from the start of the record.
1866    This is a tree of type sizetype.  */
1867
1868 tree
1869 byte_position (tree field)
1870 {
1871   return byte_from_pos (DECL_FIELD_OFFSET (field),
1872                         DECL_FIELD_BIT_OFFSET (field));
1873 }
1874
1875 /* Likewise, but return as an integer.  It must be representable in
1876    that way (since it could be a signed value, we don't have the
1877    option of returning -1 like int_size_in_byte can.  */
1878
1879 HOST_WIDE_INT
1880 int_byte_position (tree field)
1881 {
1882   return tree_low_cst (byte_position (field), 0);
1883 }
1884 \f
1885 /* Return the strictest alignment, in bits, that T is known to have.  */
1886
1887 unsigned int
1888 expr_align (tree t)
1889 {
1890   unsigned int align0, align1;
1891
1892   switch (TREE_CODE (t))
1893     {
1894     case NOP_EXPR:  case CONVERT_EXPR:  case NON_LVALUE_EXPR:
1895       /* If we have conversions, we know that the alignment of the
1896          object must meet each of the alignments of the types.  */
1897       align0 = expr_align (TREE_OPERAND (t, 0));
1898       align1 = TYPE_ALIGN (TREE_TYPE (t));
1899       return MAX (align0, align1);
1900
1901     case MODIFY_EXPR:
1902       /* FIXME tuples: It is unclear to me if this function, which
1903          is only called from ADA, is called on gimple or non gimple
1904          trees.  Let's assume it's from gimple trees unless we hit
1905          this abort.  */
1906       gcc_unreachable ();
1907
1908     case SAVE_EXPR:         case COMPOUND_EXPR:       case GIMPLE_MODIFY_STMT:
1909     case INIT_EXPR:         case TARGET_EXPR:         case WITH_CLEANUP_EXPR:
1910     case CLEANUP_POINT_EXPR:
1911       /* These don't change the alignment of an object.  */
1912       return expr_align (TREE_OPERAND (t, 0));
1913
1914     case COND_EXPR:
1915       /* The best we can do is say that the alignment is the least aligned
1916          of the two arms.  */
1917       align0 = expr_align (TREE_OPERAND (t, 1));
1918       align1 = expr_align (TREE_OPERAND (t, 2));
1919       return MIN (align0, align1);
1920
1921     case LABEL_DECL:     case CONST_DECL:
1922     case VAR_DECL:       case PARM_DECL:   case RESULT_DECL:
1923       if (DECL_ALIGN (t) != 0)
1924         return DECL_ALIGN (t);
1925       break;
1926
1927     case FUNCTION_DECL:
1928       return FUNCTION_BOUNDARY;
1929
1930     default:
1931       break;
1932     }
1933
1934   /* Otherwise take the alignment from that of the type.  */
1935   return TYPE_ALIGN (TREE_TYPE (t));
1936 }
1937 \f
1938 /* Return, as a tree node, the number of elements for TYPE (which is an
1939    ARRAY_TYPE) minus one. This counts only elements of the top array.  */
1940
1941 tree
1942 array_type_nelts (tree type)
1943 {
1944   tree index_type, min, max;
1945
1946   /* If they did it with unspecified bounds, then we should have already
1947      given an error about it before we got here.  */
1948   if (! TYPE_DOMAIN (type))
1949     return error_mark_node;
1950
1951   index_type = TYPE_DOMAIN (type);
1952   min = TYPE_MIN_VALUE (index_type);
1953   max = TYPE_MAX_VALUE (index_type);
1954
1955   return (integer_zerop (min)
1956           ? max
1957           : fold_build2 (MINUS_EXPR, TREE_TYPE (max), max, min));
1958 }
1959 \f
1960 /* If arg is static -- a reference to an object in static storage -- then
1961    return the object.  This is not the same as the C meaning of `static'.
1962    If arg isn't static, return NULL.  */
1963
1964 tree
1965 staticp (tree arg)
1966 {
1967   switch (TREE_CODE (arg))
1968     {
1969     case FUNCTION_DECL:
1970       /* Nested functions are static, even though taking their address will
1971          involve a trampoline as we unnest the nested function and create
1972          the trampoline on the tree level.  */
1973       return arg;
1974
1975     case VAR_DECL:
1976       return ((TREE_STATIC (arg) || DECL_EXTERNAL (arg))
1977               && ! DECL_THREAD_LOCAL_P (arg)
1978               && ! DECL_DLLIMPORT_P (arg)
1979               ? arg : NULL);
1980
1981     case CONST_DECL:
1982       return ((TREE_STATIC (arg) || DECL_EXTERNAL (arg))
1983               ? arg : NULL);
1984
1985     case CONSTRUCTOR:
1986       return TREE_STATIC (arg) ? arg : NULL;
1987
1988     case LABEL_DECL:
1989     case STRING_CST:
1990       return arg;
1991
1992     case COMPONENT_REF:
1993       /* If the thing being referenced is not a field, then it is
1994          something language specific.  */
1995       if (TREE_CODE (TREE_OPERAND (arg, 1)) != FIELD_DECL)
1996         return (*lang_hooks.staticp) (arg);
1997
1998       /* If we are referencing a bitfield, we can't evaluate an
1999          ADDR_EXPR at compile time and so it isn't a constant.  */
2000       if (DECL_BIT_FIELD (TREE_OPERAND (arg, 1)))
2001         return NULL;
2002
2003       return staticp (TREE_OPERAND (arg, 0));
2004
2005     case BIT_FIELD_REF:
2006       return NULL;
2007
2008     case MISALIGNED_INDIRECT_REF:
2009     case ALIGN_INDIRECT_REF:
2010     case INDIRECT_REF:
2011       return TREE_CONSTANT (TREE_OPERAND (arg, 0)) ? arg : NULL;
2012
2013     case ARRAY_REF:
2014     case ARRAY_RANGE_REF:
2015       if (TREE_CODE (TYPE_SIZE (TREE_TYPE (arg))) == INTEGER_CST
2016           && TREE_CODE (TREE_OPERAND (arg, 1)) == INTEGER_CST)
2017         return staticp (TREE_OPERAND (arg, 0));
2018       else
2019         return false;
2020
2021     default:
2022       if ((unsigned int) TREE_CODE (arg)
2023           >= (unsigned int) LAST_AND_UNUSED_TREE_CODE)
2024         return lang_hooks.staticp (arg);
2025       else
2026         return NULL;
2027     }
2028 }
2029 \f
2030 /* Wrap a SAVE_EXPR around EXPR, if appropriate.
2031    Do this to any expression which may be used in more than one place,
2032    but must be evaluated only once.
2033
2034    Normally, expand_expr would reevaluate the expression each time.
2035    Calling save_expr produces something that is evaluated and recorded
2036    the first time expand_expr is called on it.  Subsequent calls to
2037    expand_expr just reuse the recorded value.
2038
2039    The call to expand_expr that generates code that actually computes
2040    the value is the first call *at compile time*.  Subsequent calls
2041    *at compile time* generate code to use the saved value.
2042    This produces correct result provided that *at run time* control
2043    always flows through the insns made by the first expand_expr
2044    before reaching the other places where the save_expr was evaluated.
2045    You, the caller of save_expr, must make sure this is so.
2046
2047    Constants, and certain read-only nodes, are returned with no
2048    SAVE_EXPR because that is safe.  Expressions containing placeholders
2049    are not touched; see tree.def for an explanation of what these
2050    are used for.  */
2051
2052 tree
2053 save_expr (tree expr)
2054 {
2055   tree t = fold (expr);
2056   tree inner;
2057
2058   /* If the tree evaluates to a constant, then we don't want to hide that
2059      fact (i.e. this allows further folding, and direct checks for constants).
2060      However, a read-only object that has side effects cannot be bypassed.
2061      Since it is no problem to reevaluate literals, we just return the
2062      literal node.  */
2063   inner = skip_simple_arithmetic (t);
2064
2065   if (TREE_INVARIANT (inner)
2066       || (TREE_READONLY (inner) && ! TREE_SIDE_EFFECTS (inner))
2067       || TREE_CODE (inner) == SAVE_EXPR
2068       || TREE_CODE (inner) == ERROR_MARK)
2069     return t;
2070
2071   /* If INNER contains a PLACEHOLDER_EXPR, we must evaluate it each time, since
2072      it means that the size or offset of some field of an object depends on
2073      the value within another field.
2074
2075      Note that it must not be the case that T contains both a PLACEHOLDER_EXPR
2076      and some variable since it would then need to be both evaluated once and
2077      evaluated more than once.  Front-ends must assure this case cannot
2078      happen by surrounding any such subexpressions in their own SAVE_EXPR
2079      and forcing evaluation at the proper time.  */
2080   if (contains_placeholder_p (inner))
2081     return t;
2082
2083   t = build1 (SAVE_EXPR, TREE_TYPE (expr), t);
2084
2085   /* This expression might be placed ahead of a jump to ensure that the
2086      value was computed on both sides of the jump.  So make sure it isn't
2087      eliminated as dead.  */
2088   TREE_SIDE_EFFECTS (t) = 1;
2089   TREE_INVARIANT (t) = 1;
2090   return t;
2091 }
2092
2093 /* Look inside EXPR and into any simple arithmetic operations.  Return
2094    the innermost non-arithmetic node.  */
2095
2096 tree
2097 skip_simple_arithmetic (tree expr)
2098 {
2099   tree inner;
2100
2101   /* We don't care about whether this can be used as an lvalue in this
2102      context.  */
2103   while (TREE_CODE (expr) == NON_LVALUE_EXPR)
2104     expr = TREE_OPERAND (expr, 0);
2105
2106   /* If we have simple operations applied to a SAVE_EXPR or to a SAVE_EXPR and
2107      a constant, it will be more efficient to not make another SAVE_EXPR since
2108      it will allow better simplification and GCSE will be able to merge the
2109      computations if they actually occur.  */
2110   inner = expr;
2111   while (1)
2112     {
2113       if (UNARY_CLASS_P (inner))
2114         inner = TREE_OPERAND (inner, 0);
2115       else if (BINARY_CLASS_P (inner))
2116         {
2117           if (TREE_INVARIANT (TREE_OPERAND (inner, 1)))
2118             inner = TREE_OPERAND (inner, 0);
2119           else if (TREE_INVARIANT (TREE_OPERAND (inner, 0)))
2120             inner = TREE_OPERAND (inner, 1);
2121           else
2122             break;
2123         }
2124       else
2125         break;
2126     }
2127
2128   return inner;
2129 }
2130
2131 /* Return which tree structure is used by T.  */
2132
2133 enum tree_node_structure_enum
2134 tree_node_structure (tree t)
2135 {
2136   enum tree_code code = TREE_CODE (t);
2137
2138   switch (TREE_CODE_CLASS (code))
2139     {
2140     case tcc_declaration:
2141       {
2142         switch (code)
2143           {
2144           case FIELD_DECL:
2145             return TS_FIELD_DECL;
2146           case PARM_DECL:
2147             return TS_PARM_DECL;
2148           case VAR_DECL:
2149             return TS_VAR_DECL;
2150           case LABEL_DECL:
2151             return TS_LABEL_DECL;
2152           case RESULT_DECL:
2153             return TS_RESULT_DECL;
2154           case CONST_DECL:
2155             return TS_CONST_DECL;
2156           case TYPE_DECL:
2157             return TS_TYPE_DECL;
2158           case FUNCTION_DECL:
2159             return TS_FUNCTION_DECL;
2160           case SYMBOL_MEMORY_TAG:
2161           case NAME_MEMORY_TAG:
2162           case STRUCT_FIELD_TAG:
2163           case MEMORY_PARTITION_TAG:
2164             return TS_MEMORY_TAG;
2165           default:
2166             return TS_DECL_NON_COMMON;
2167           }
2168       }
2169     case tcc_type:
2170       return TS_TYPE;
2171     case tcc_reference:
2172     case tcc_comparison:
2173     case tcc_unary:
2174     case tcc_binary:
2175     case tcc_expression:
2176     case tcc_statement:
2177       return TS_EXP;
2178     case tcc_gimple_stmt:
2179       return TS_GIMPLE_STATEMENT;
2180     default:  /* tcc_constant and tcc_exceptional */
2181       break;
2182     }
2183   switch (code)
2184     {
2185       /* tcc_constant cases.  */
2186     case INTEGER_CST:           return TS_INT_CST;
2187     case REAL_CST:              return TS_REAL_CST;
2188     case COMPLEX_CST:           return TS_COMPLEX;
2189     case VECTOR_CST:            return TS_VECTOR;
2190     case STRING_CST:            return TS_STRING;
2191       /* tcc_exceptional cases.  */
2192     /* FIXME tuples: eventually this should be TS_BASE.  For now, nothing
2193        returns TS_BASE.  */
2194     case ERROR_MARK:            return TS_COMMON;
2195     case IDENTIFIER_NODE:       return TS_IDENTIFIER;
2196     case TREE_LIST:             return TS_LIST;
2197     case TREE_VEC:              return TS_VEC;
2198     case PHI_NODE:              return TS_PHI_NODE;
2199     case SSA_NAME:              return TS_SSA_NAME;
2200     case PLACEHOLDER_EXPR:      return TS_COMMON;
2201     case STATEMENT_LIST:        return TS_STATEMENT_LIST;
2202     case BLOCK:                 return TS_BLOCK;
2203     case CONSTRUCTOR:           return TS_CONSTRUCTOR;
2204     case TREE_BINFO:            return TS_BINFO;
2205     case VALUE_HANDLE:          return TS_VALUE_HANDLE;
2206     case OMP_CLAUSE:            return TS_OMP_CLAUSE;
2207
2208     default:
2209       gcc_unreachable ();
2210     }
2211 }
2212 \f
2213 /* Return 1 if EXP contains a PLACEHOLDER_EXPR; i.e., if it represents a size
2214    or offset that depends on a field within a record.  */
2215
2216 bool
2217 contains_placeholder_p (tree exp)
2218 {
2219   enum tree_code code;
2220
2221   if (!exp)
2222     return 0;
2223
2224   code = TREE_CODE (exp);
2225   if (code == PLACEHOLDER_EXPR)
2226     return 1;
2227
2228   switch (TREE_CODE_CLASS (code))
2229     {
2230     case tcc_reference:
2231       /* Don't look at any PLACEHOLDER_EXPRs that might be in index or bit
2232          position computations since they will be converted into a
2233          WITH_RECORD_EXPR involving the reference, which will assume
2234          here will be valid.  */
2235       return CONTAINS_PLACEHOLDER_P (TREE_OPERAND (exp, 0));
2236
2237     case tcc_exceptional:
2238       if (code == TREE_LIST)
2239         return (CONTAINS_PLACEHOLDER_P (TREE_VALUE (exp))
2240                 || CONTAINS_PLACEHOLDER_P (TREE_CHAIN (exp)));
2241       break;
2242
2243     case tcc_unary:
2244     case tcc_binary:
2245     case tcc_comparison:
2246     case tcc_expression:
2247       switch (code)
2248         {
2249         case COMPOUND_EXPR:
2250           /* Ignoring the first operand isn't quite right, but works best.  */
2251           return CONTAINS_PLACEHOLDER_P (TREE_OPERAND (exp, 1));
2252
2253         case COND_EXPR:
2254           return (CONTAINS_PLACEHOLDER_P (TREE_OPERAND (exp, 0))
2255                   || CONTAINS_PLACEHOLDER_P (TREE_OPERAND (exp, 1))
2256                   || CONTAINS_PLACEHOLDER_P (TREE_OPERAND (exp, 2)));
2257
2258         case CALL_EXPR:
2259           return CONTAINS_PLACEHOLDER_P (TREE_OPERAND (exp, 1));
2260
2261         default:
2262           break;
2263         }
2264
2265       switch (TREE_CODE_LENGTH (code))
2266         {
2267         case 1:
2268           return CONTAINS_PLACEHOLDER_P (TREE_OPERAND (exp, 0));
2269         case 2:
2270           return (CONTAINS_PLACEHOLDER_P (TREE_OPERAND (exp, 0))
2271                   || CONTAINS_PLACEHOLDER_P (TREE_OPERAND (exp, 1)));
2272         default:
2273           return 0;
2274         }
2275
2276     default:
2277       return 0;
2278     }
2279   return 0;
2280 }
2281
2282 /* Return true if any part of the computation of TYPE involves a
2283    PLACEHOLDER_EXPR.  This includes size, bounds, qualifiers
2284    (for QUAL_UNION_TYPE) and field positions.  */
2285
2286 static bool
2287 type_contains_placeholder_1 (tree type)
2288 {
2289   /* If the size contains a placeholder or the parent type (component type in
2290      the case of arrays) type involves a placeholder, this type does.  */
2291   if (CONTAINS_PLACEHOLDER_P (TYPE_SIZE (type))
2292       || CONTAINS_PLACEHOLDER_P (TYPE_SIZE_UNIT (type))
2293       || (TREE_TYPE (type) != 0
2294           && type_contains_placeholder_p (TREE_TYPE (type))))
2295     return true;
2296
2297   /* Now do type-specific checks.  Note that the last part of the check above
2298      greatly limits what we have to do below.  */
2299   switch (TREE_CODE (type))
2300     {
2301     case VOID_TYPE:
2302     case COMPLEX_TYPE:
2303     case ENUMERAL_TYPE:
2304     case BOOLEAN_TYPE:
2305     case POINTER_TYPE:
2306     case OFFSET_TYPE:
2307     case REFERENCE_TYPE:
2308     case METHOD_TYPE:
2309     case FUNCTION_TYPE:
2310     case VECTOR_TYPE:
2311       return false;
2312
2313     case INTEGER_TYPE:
2314     case REAL_TYPE:
2315       /* Here we just check the bounds.  */
2316       return (CONTAINS_PLACEHOLDER_P (TYPE_MIN_VALUE (type))
2317               || CONTAINS_PLACEHOLDER_P (TYPE_MAX_VALUE (type)));
2318
2319     case ARRAY_TYPE:
2320       /* We're already checked the component type (TREE_TYPE), so just check
2321          the index type.  */
2322       return type_contains_placeholder_p (TYPE_DOMAIN (type));
2323
2324     case RECORD_TYPE:
2325     case UNION_TYPE:
2326     case QUAL_UNION_TYPE:
2327       {
2328         tree field;
2329
2330         for (field = TYPE_FIELDS (type); field; field = TREE_CHAIN (field))
2331           if (TREE_CODE (field) == FIELD_DECL
2332               && (CONTAINS_PLACEHOLDER_P (DECL_FIELD_OFFSET (field))
2333                   || (TREE_CODE (type) == QUAL_UNION_TYPE
2334                       && CONTAINS_PLACEHOLDER_P (DECL_QUALIFIER (field)))
2335                   || type_contains_placeholder_p (TREE_TYPE (field))))
2336             return true;
2337
2338         return false;
2339       }
2340
2341     default:
2342       gcc_unreachable ();
2343     }
2344 }
2345
2346 bool
2347 type_contains_placeholder_p (tree type)
2348 {
2349   bool result;
2350
2351   /* If the contains_placeholder_bits field has been initialized,
2352      then we know the answer.  */
2353   if (TYPE_CONTAINS_PLACEHOLDER_INTERNAL (type) > 0)
2354     return TYPE_CONTAINS_PLACEHOLDER_INTERNAL (type) - 1;
2355
2356   /* Indicate that we've seen this type node, and the answer is false.
2357      This is what we want to return if we run into recursion via fields.  */
2358   TYPE_CONTAINS_PLACEHOLDER_INTERNAL (type) = 1;
2359
2360   /* Compute the real value.  */
2361   result = type_contains_placeholder_1 (type);
2362
2363   /* Store the real value.  */
2364   TYPE_CONTAINS_PLACEHOLDER_INTERNAL (type) = result + 1;
2365
2366   return result;
2367 }
2368 \f
2369 /* Given a tree EXP, a FIELD_DECL F, and a replacement value R,
2370    return a tree with all occurrences of references to F in a
2371    PLACEHOLDER_EXPR replaced by R.   Note that we assume here that EXP
2372    contains only arithmetic expressions or a CALL_EXPR with a
2373    PLACEHOLDER_EXPR occurring only in its arglist.  */
2374
2375 tree
2376 substitute_in_expr (tree exp, tree f, tree r)
2377 {
2378   enum tree_code code = TREE_CODE (exp);
2379   tree op0, op1, op2, op3;
2380   tree new;
2381   tree inner;
2382
2383   /* We handle TREE_LIST and COMPONENT_REF separately.  */
2384   if (code == TREE_LIST)
2385     {
2386       op0 = SUBSTITUTE_IN_EXPR (TREE_CHAIN (exp), f, r);
2387       op1 = SUBSTITUTE_IN_EXPR (TREE_VALUE (exp), f, r);
2388       if (op0 == TREE_CHAIN (exp) && op1 == TREE_VALUE (exp))
2389         return exp;
2390
2391       return tree_cons (TREE_PURPOSE (exp), op1, op0);
2392     }
2393   else if (code == COMPONENT_REF)
2394    {
2395      /* If this expression is getting a value from a PLACEHOLDER_EXPR
2396         and it is the right field, replace it with R.  */
2397      for (inner = TREE_OPERAND (exp, 0);
2398           REFERENCE_CLASS_P (inner);
2399           inner = TREE_OPERAND (inner, 0))
2400        ;
2401      if (TREE_CODE (inner) == PLACEHOLDER_EXPR
2402          && TREE_OPERAND (exp, 1) == f)
2403        return r;
2404
2405      /* If this expression hasn't been completed let, leave it alone.  */
2406      if (TREE_CODE (inner) == PLACEHOLDER_EXPR && TREE_TYPE (inner) == 0)
2407        return exp;
2408
2409      op0 = SUBSTITUTE_IN_EXPR (TREE_OPERAND (exp, 0), f, r);
2410      if (op0 == TREE_OPERAND (exp, 0))
2411        return exp;
2412
2413      new = fold_build3 (COMPONENT_REF, TREE_TYPE (exp),
2414                         op0, TREE_OPERAND (exp, 1), NULL_TREE);
2415    }
2416   else
2417     switch (TREE_CODE_CLASS (code))
2418       {
2419       case tcc_constant:
2420       case tcc_declaration:
2421         return exp;
2422
2423       case tcc_exceptional:
2424       case tcc_unary:
2425       case tcc_binary:
2426       case tcc_comparison:
2427       case tcc_expression:
2428       case tcc_reference:
2429         switch (TREE_CODE_LENGTH (code))
2430           {
2431           case 0:
2432             return exp;
2433
2434           case 1:
2435             op0 = SUBSTITUTE_IN_EXPR (TREE_OPERAND (exp, 0), f, r);
2436             if (op0 == TREE_OPERAND (exp, 0))
2437               return exp;
2438
2439             new = fold_build1 (code, TREE_TYPE (exp), op0);
2440             break;
2441
2442           case 2:
2443             op0 = SUBSTITUTE_IN_EXPR (TREE_OPERAND (exp, 0), f, r);
2444             op1 = SUBSTITUTE_IN_EXPR (TREE_OPERAND (exp, 1), f, r);
2445
2446             if (op0 == TREE_OPERAND (exp, 0) && op1 == TREE_OPERAND (exp, 1))
2447               return exp;
2448
2449             new = fold_build2 (code, TREE_TYPE (exp), op0, op1);
2450             break;
2451
2452           case 3:
2453             op0 = SUBSTITUTE_IN_EXPR (TREE_OPERAND (exp, 0), f, r);
2454             op1 = SUBSTITUTE_IN_EXPR (TREE_OPERAND (exp, 1), f, r);
2455             op2 = SUBSTITUTE_IN_EXPR (TREE_OPERAND (exp, 2), f, r);
2456
2457             if (op0 == TREE_OPERAND (exp, 0) && op1 == TREE_OPERAND (exp, 1)
2458                 && op2 == TREE_OPERAND (exp, 2))
2459               return exp;
2460
2461             new = fold_build3 (code, TREE_TYPE (exp), op0, op1, op2);
2462             break;
2463
2464           case 4:
2465             op0 = SUBSTITUTE_IN_EXPR (TREE_OPERAND (exp, 0), f, r);
2466             op1 = SUBSTITUTE_IN_EXPR (TREE_OPERAND (exp, 1), f, r);
2467             op2 = SUBSTITUTE_IN_EXPR (TREE_OPERAND (exp, 2), f, r);
2468             op3 = SUBSTITUTE_IN_EXPR (TREE_OPERAND (exp, 3), f, r);
2469
2470             if (op0 == TREE_OPERAND (exp, 0) && op1 == TREE_OPERAND (exp, 1)
2471                 && op2 == TREE_OPERAND (exp, 2)
2472                 && op3 == TREE_OPERAND (exp, 3))
2473               return exp;
2474
2475             new = fold (build4 (code, TREE_TYPE (exp), op0, op1, op2, op3));
2476             break;
2477
2478           default:
2479             gcc_unreachable ();
2480           }
2481         break;
2482
2483       default:
2484         gcc_unreachable ();
2485       }
2486
2487   TREE_READONLY (new) = TREE_READONLY (exp);
2488   return new;
2489 }
2490
2491 /* Similar, but look for a PLACEHOLDER_EXPR in EXP and find a replacement
2492    for it within OBJ, a tree that is an object or a chain of references.  */
2493
2494 tree
2495 substitute_placeholder_in_expr (tree exp, tree obj)
2496 {
2497   enum tree_code code = TREE_CODE (exp);
2498   tree op0, op1, op2, op3;
2499
2500   /* If this is a PLACEHOLDER_EXPR, see if we find a corresponding type
2501      in the chain of OBJ.  */
2502   if (code == PLACEHOLDER_EXPR)
2503     {
2504       tree need_type = TYPE_MAIN_VARIANT (TREE_TYPE (exp));
2505       tree elt;
2506
2507       for (elt = obj; elt != 0;
2508            elt = ((TREE_CODE (elt) == COMPOUND_EXPR
2509                    || TREE_CODE (elt) == COND_EXPR)
2510                   ? TREE_OPERAND (elt, 1)
2511                   : (REFERENCE_CLASS_P (elt)
2512                      || UNARY_CLASS_P (elt)
2513                      || BINARY_CLASS_P (elt)
2514                      || EXPRESSION_CLASS_P (elt))
2515                   ? TREE_OPERAND (elt, 0) : 0))
2516         if (TYPE_MAIN_VARIANT (TREE_TYPE (elt)) == need_type)
2517           return elt;
2518
2519       for (elt = obj; elt != 0;
2520            elt = ((TREE_CODE (elt) == COMPOUND_EXPR
2521                    || TREE_CODE (elt) == COND_EXPR)
2522                   ? TREE_OPERAND (elt, 1)
2523                   : (REFERENCE_CLASS_P (elt)
2524                      || UNARY_CLASS_P (elt)
2525                      || BINARY_CLASS_P (elt)
2526                      || EXPRESSION_CLASS_P (elt))
2527                   ? TREE_OPERAND (elt, 0) : 0))
2528         if (POINTER_TYPE_P (TREE_TYPE (elt))
2529             && (TYPE_MAIN_VARIANT (TREE_TYPE (TREE_TYPE (elt)))
2530                 == need_type))
2531           return fold_build1 (INDIRECT_REF, need_type, elt);
2532
2533       /* If we didn't find it, return the original PLACEHOLDER_EXPR.  If it
2534          survives until RTL generation, there will be an error.  */
2535       return exp;
2536     }
2537
2538   /* TREE_LIST is special because we need to look at TREE_VALUE
2539      and TREE_CHAIN, not TREE_OPERANDS.  */
2540   else if (code == TREE_LIST)
2541     {
2542       op0 = SUBSTITUTE_PLACEHOLDER_IN_EXPR (TREE_CHAIN (exp), obj);
2543       op1 = SUBSTITUTE_PLACEHOLDER_IN_EXPR (TREE_VALUE (exp), obj);
2544       if (op0 == TREE_CHAIN (exp) && op1 == TREE_VALUE (exp))
2545         return exp;
2546
2547       return tree_cons (TREE_PURPOSE (exp), op1, op0);
2548     }
2549   else
2550     switch (TREE_CODE_CLASS (code))
2551       {
2552       case tcc_constant:
2553       case tcc_declaration:
2554         return exp;
2555
2556       case tcc_exceptional:
2557       case tcc_unary:
2558       case tcc_binary:
2559       case tcc_comparison:
2560       case tcc_expression:
2561       case tcc_reference:
2562       case tcc_statement:
2563         switch (TREE_CODE_LENGTH (code))
2564           {
2565           case 0:
2566             return exp;
2567
2568           case 1:
2569             op0 = SUBSTITUTE_PLACEHOLDER_IN_EXPR (TREE_OPERAND (exp, 0), obj);
2570             if (op0 == TREE_OPERAND (exp, 0))
2571               return exp;
2572             else
2573               return fold_build1 (code, TREE_TYPE (exp), op0);
2574
2575           case 2:
2576             op0 = SUBSTITUTE_PLACEHOLDER_IN_EXPR (TREE_OPERAND (exp, 0), obj);
2577             op1 = SUBSTITUTE_PLACEHOLDER_IN_EXPR (TREE_OPERAND (exp, 1), obj);
2578
2579             if (op0 == TREE_OPERAND (exp, 0) && op1 == TREE_OPERAND (exp, 1))
2580               return exp;
2581             else
2582               return fold_build2 (code, TREE_TYPE (exp), op0, op1);
2583
2584           case 3:
2585             op0 = SUBSTITUTE_PLACEHOLDER_IN_EXPR (TREE_OPERAND (exp, 0), obj);
2586             op1 = SUBSTITUTE_PLACEHOLDER_IN_EXPR (TREE_OPERAND (exp, 1), obj);
2587             op2 = SUBSTITUTE_PLACEHOLDER_IN_EXPR (TREE_OPERAND (exp, 2), obj);
2588
2589             if (op0 == TREE_OPERAND (exp, 0) && op1 == TREE_OPERAND (exp, 1)
2590                 && op2 == TREE_OPERAND (exp, 2))
2591               return exp;
2592             else
2593               return fold_build3 (code, TREE_TYPE (exp), op0, op1, op2);
2594
2595           case 4:
2596             op0 = SUBSTITUTE_PLACEHOLDER_IN_EXPR (TREE_OPERAND (exp, 0), obj);
2597             op1 = SUBSTITUTE_PLACEHOLDER_IN_EXPR (TREE_OPERAND (exp, 1), obj);
2598             op2 = SUBSTITUTE_PLACEHOLDER_IN_EXPR (TREE_OPERAND (exp, 2), obj);
2599             op3 = SUBSTITUTE_PLACEHOLDER_IN_EXPR (TREE_OPERAND (exp, 3), obj);
2600
2601             if (op0 == TREE_OPERAND (exp, 0) && op1 == TREE_OPERAND (exp, 1)
2602                 && op2 == TREE_OPERAND (exp, 2)
2603                 && op3 == TREE_OPERAND (exp, 3))
2604               return exp;
2605             else
2606               return fold (build4 (code, TREE_TYPE (exp), op0, op1, op2, op3));
2607
2608           default:
2609             gcc_unreachable ();
2610           }
2611         break;
2612
2613       default:
2614         gcc_unreachable ();
2615       }
2616 }
2617 \f
2618 /* Stabilize a reference so that we can use it any number of times
2619    without causing its operands to be evaluated more than once.
2620    Returns the stabilized reference.  This works by means of save_expr,
2621    so see the caveats in the comments about save_expr.
2622
2623    Also allows conversion expressions whose operands are references.
2624    Any other kind of expression is returned unchanged.  */
2625
2626 tree
2627 stabilize_reference (tree ref)
2628 {
2629   tree result;
2630   enum tree_code code = TREE_CODE (ref);
2631
2632   switch (code)
2633     {
2634     case VAR_DECL:
2635     case PARM_DECL:
2636     case RESULT_DECL:
2637       /* No action is needed in this case.  */
2638       return ref;
2639
2640     case NOP_EXPR:
2641     case CONVERT_EXPR:
2642     case FLOAT_EXPR:
2643     case FIX_TRUNC_EXPR:
2644       result = build_nt (code, stabilize_reference (TREE_OPERAND (ref, 0)));
2645       break;
2646
2647     case INDIRECT_REF:
2648       result = build_nt (INDIRECT_REF,
2649                          stabilize_reference_1 (TREE_OPERAND (ref, 0)));
2650       break;
2651
2652     case COMPONENT_REF:
2653       result = build_nt (COMPONENT_REF,
2654                          stabilize_reference (TREE_OPERAND (ref, 0)),
2655                          TREE_OPERAND (ref, 1), NULL_TREE);
2656       break;
2657
2658     case BIT_FIELD_REF:
2659       result = build_nt (BIT_FIELD_REF,
2660                          stabilize_reference (TREE_OPERAND (ref, 0)),
2661                          stabilize_reference_1 (TREE_OPERAND (ref, 1)),
2662                          stabilize_reference_1 (TREE_OPERAND (ref, 2)));
2663       break;
2664
2665     case ARRAY_REF:
2666       result = build_nt (ARRAY_REF,
2667                          stabilize_reference (TREE_OPERAND (ref, 0)),
2668                          stabilize_reference_1 (TREE_OPERAND (ref, 1)),
2669                          TREE_OPERAND (ref, 2), TREE_OPERAND (ref, 3));
2670       break;
2671
2672     case ARRAY_RANGE_REF:
2673       result = build_nt (ARRAY_RANGE_REF,
2674                          stabilize_reference (TREE_OPERAND (ref, 0)),
2675                          stabilize_reference_1 (TREE_OPERAND (ref, 1)),
2676                          TREE_OPERAND (ref, 2), TREE_OPERAND (ref, 3));
2677       break;
2678
2679     case COMPOUND_EXPR:
2680       /* We cannot wrap the first expression in a SAVE_EXPR, as then
2681          it wouldn't be ignored.  This matters when dealing with
2682          volatiles.  */
2683       return stabilize_reference_1 (ref);
2684
2685       /* If arg isn't a kind of lvalue we recognize, make no change.
2686          Caller should recognize the error for an invalid lvalue.  */
2687     default:
2688       return ref;
2689
2690     case ERROR_MARK:
2691       return error_mark_node;
2692     }
2693
2694   TREE_TYPE (result) = TREE_TYPE (ref);
2695   TREE_READONLY (result) = TREE_READONLY (ref);
2696   TREE_SIDE_EFFECTS (result) = TREE_SIDE_EFFECTS (ref);
2697   TREE_THIS_VOLATILE (result) = TREE_THIS_VOLATILE (ref);
2698
2699   return result;
2700 }
2701
2702 /* Subroutine of stabilize_reference; this is called for subtrees of
2703    references.  Any expression with side-effects must be put in a SAVE_EXPR
2704    to ensure that it is only evaluated once.
2705
2706    We don't put SAVE_EXPR nodes around everything, because assigning very
2707    simple expressions to temporaries causes us to miss good opportunities
2708    for optimizations.  Among other things, the opportunity to fold in the
2709    addition of a constant into an addressing mode often gets lost, e.g.
2710    "y[i+1] += x;".  In general, we take the approach that we should not make
2711    an assignment unless we are forced into it - i.e., that any non-side effect
2712    operator should be allowed, and that cse should take care of coalescing
2713    multiple utterances of the same expression should that prove fruitful.  */
2714
2715 tree
2716 stabilize_reference_1 (tree e)
2717 {
2718   tree result;
2719   enum tree_code code = TREE_CODE (e);
2720
2721   /* We cannot ignore const expressions because it might be a reference
2722      to a const array but whose index contains side-effects.  But we can
2723      ignore things that are actual constant or that already have been
2724      handled by this function.  */
2725
2726   if (TREE_INVARIANT (e))
2727     return e;
2728
2729   switch (TREE_CODE_CLASS (code))
2730     {
2731     case tcc_exceptional:
2732     case tcc_type:
2733     case tcc_declaration:
2734     case tcc_comparison:
2735     case tcc_statement:
2736     case tcc_expression:
2737     case tcc_reference:
2738       /* If the expression has side-effects, then encase it in a SAVE_EXPR
2739          so that it will only be evaluated once.  */
2740       /* The reference (r) and comparison (<) classes could be handled as
2741          below, but it is generally faster to only evaluate them once.  */
2742       if (TREE_SIDE_EFFECTS (e))
2743         return save_expr (e);
2744       return e;
2745
2746     case tcc_constant:
2747       /* Constants need no processing.  In fact, we should never reach
2748          here.  */
2749       return e;
2750
2751     case tcc_binary:
2752       /* Division is slow and tends to be compiled with jumps,
2753          especially the division by powers of 2 that is often
2754          found inside of an array reference.  So do it just once.  */
2755       if (code == TRUNC_DIV_EXPR || code == TRUNC_MOD_EXPR
2756           || code == FLOOR_DIV_EXPR || code == FLOOR_MOD_EXPR
2757           || code == CEIL_DIV_EXPR || code == CEIL_MOD_EXPR
2758           || code == ROUND_DIV_EXPR || code == ROUND_MOD_EXPR)
2759         return save_expr (e);
2760       /* Recursively stabilize each operand.  */
2761       result = build_nt (code, stabilize_reference_1 (TREE_OPERAND (e, 0)),
2762                          stabilize_reference_1 (TREE_OPERAND (e, 1)));
2763       break;
2764
2765     case tcc_unary:
2766       /* Recursively stabilize each operand.  */
2767       result = build_nt (code, stabilize_reference_1 (TREE_OPERAND (e, 0)));
2768       break;
2769
2770     default:
2771       gcc_unreachable ();
2772     }
2773
2774   TREE_TYPE (result) = TREE_TYPE (e);
2775   TREE_READONLY (result) = TREE_READONLY (e);
2776   TREE_SIDE_EFFECTS (result) = TREE_SIDE_EFFECTS (e);
2777   TREE_THIS_VOLATILE (result) = TREE_THIS_VOLATILE (e);
2778   TREE_INVARIANT (result) = 1;
2779
2780   return result;
2781 }
2782 \f
2783 /* Low-level constructors for expressions.  */
2784
2785 /* A helper function for build1 and constant folders.  Set TREE_CONSTANT,
2786    TREE_INVARIANT, and TREE_SIDE_EFFECTS for an ADDR_EXPR.  */
2787
2788 void
2789 recompute_tree_invariant_for_addr_expr (tree t)
2790 {
2791   tree node;
2792   bool tc = true, ti = true, se = false;
2793
2794   /* We started out assuming this address is both invariant and constant, but
2795      does not have side effects.  Now go down any handled components and see if
2796      any of them involve offsets that are either non-constant or non-invariant.
2797      Also check for side-effects.
2798
2799      ??? Note that this code makes no attempt to deal with the case where
2800      taking the address of something causes a copy due to misalignment.  */
2801
2802 #define UPDATE_TITCSE(NODE)  \
2803 do { tree _node = (NODE); \
2804      if (_node && !TREE_INVARIANT (_node)) ti = false; \
2805      if (_node && !TREE_CONSTANT (_node)) tc = false; \
2806      if (_node && TREE_SIDE_EFFECTS (_node)) se = true; } while (0)
2807
2808   for (node = TREE_OPERAND (t, 0); handled_component_p (node);
2809        node = TREE_OPERAND (node, 0))
2810     {
2811       /* If the first operand doesn't have an ARRAY_TYPE, this is a bogus
2812          array reference (probably made temporarily by the G++ front end),
2813          so ignore all the operands.  */
2814       if ((TREE_CODE (node) == ARRAY_REF
2815            || TREE_CODE (node) == ARRAY_RANGE_REF)
2816           && TREE_CODE (TREE_TYPE (TREE_OPERAND (node, 0))) == ARRAY_TYPE)
2817         {
2818           UPDATE_TITCSE (TREE_OPERAND (node, 1));
2819           if (TREE_OPERAND (node, 2))
2820             UPDATE_TITCSE (TREE_OPERAND (node, 2));
2821           if (TREE_OPERAND (node, 3))
2822             UPDATE_TITCSE (TREE_OPERAND (node, 3));
2823         }
2824       /* Likewise, just because this is a COMPONENT_REF doesn't mean we have a
2825          FIELD_DECL, apparently.  The G++ front end can put something else
2826          there, at least temporarily.  */
2827       else if (TREE_CODE (node) == COMPONENT_REF
2828                && TREE_CODE (TREE_OPERAND (node, 1)) == FIELD_DECL)
2829         {
2830           if (TREE_OPERAND (node, 2))
2831             UPDATE_TITCSE (TREE_OPERAND (node, 2));
2832         }
2833       else if (TREE_CODE (node) == BIT_FIELD_REF)
2834         UPDATE_TITCSE (TREE_OPERAND (node, 2));
2835     }
2836
2837   node = lang_hooks.expr_to_decl (node, &tc, &ti, &se);
2838
2839   /* Now see what's inside.  If it's an INDIRECT_REF, copy our properties from
2840      the address, since &(*a)->b is a form of addition.  If it's a decl, it's
2841      invariant and constant if the decl is static.  It's also invariant if it's
2842      a decl in the current function.  Taking the address of a volatile variable
2843      is not volatile.  If it's a constant, the address is both invariant and
2844      constant.  Otherwise it's neither.  */
2845   if (TREE_CODE (node) == INDIRECT_REF)
2846     UPDATE_TITCSE (TREE_OPERAND (node, 0));
2847   else if (DECL_P (node))
2848     {
2849       if (staticp (node))
2850         ;
2851       else if (decl_function_context (node) == current_function_decl
2852                /* Addresses of thread-local variables are invariant.  */
2853                || (TREE_CODE (node) == VAR_DECL
2854                    && DECL_THREAD_LOCAL_P (node)))
2855         tc = false;
2856       else
2857         ti = tc = false;
2858     }
2859   else if (CONSTANT_CLASS_P (node))
2860     ;
2861   else
2862     {
2863       ti = tc = false;
2864       se |= TREE_SIDE_EFFECTS (node);
2865     }
2866
2867   TREE_CONSTANT (t) = tc;
2868   TREE_INVARIANT (t) = ti;
2869   TREE_SIDE_EFFECTS (t) = se;
2870 #undef UPDATE_TITCSE
2871 }
2872
2873 /* Build an expression of code CODE, data type TYPE, and operands as
2874    specified.  Expressions and reference nodes can be created this way.
2875    Constants, decls, types and misc nodes cannot be.
2876
2877    We define 5 non-variadic functions, from 0 to 4 arguments.  This is
2878    enough for all extant tree codes.  */
2879
2880 tree
2881 build0_stat (enum tree_code code, tree tt MEM_STAT_DECL)
2882 {
2883   tree t;
2884
2885   gcc_assert (TREE_CODE_LENGTH (code) == 0);
2886
2887   t = make_node_stat (code PASS_MEM_STAT);
2888   TREE_TYPE (t) = tt;
2889
2890   return t;
2891 }
2892
2893 tree
2894 build1_stat (enum tree_code code, tree type, tree node MEM_STAT_DECL)
2895 {
2896   int length = sizeof (struct tree_exp);
2897 #ifdef GATHER_STATISTICS
2898   tree_node_kind kind;
2899 #endif
2900   tree t;
2901
2902 #ifdef GATHER_STATISTICS
2903   switch (TREE_CODE_CLASS (code))
2904     {
2905     case tcc_statement:  /* an expression with side effects */
2906       kind = s_kind;
2907       break;
2908     case tcc_reference:  /* a reference */
2909       kind = r_kind;
2910       break;
2911     default:
2912       kind = e_kind;
2913       break;
2914     }
2915
2916   tree_node_counts[(int) kind]++;
2917   tree_node_sizes[(int) kind] += length;
2918 #endif
2919
2920   gcc_assert (TREE_CODE_LENGTH (code) == 1);
2921
2922   t = ggc_alloc_zone_pass_stat (length, &tree_zone);
2923
2924   memset (t, 0, sizeof (struct tree_common));
2925
2926   TREE_SET_CODE (t, code);
2927
2928   TREE_TYPE (t) = type;
2929 #ifdef USE_MAPPED_LOCATION
2930   SET_EXPR_LOCATION (t, UNKNOWN_LOCATION);
2931 #else
2932   SET_EXPR_LOCUS (t, NULL);
2933 #endif
2934   TREE_COMPLEXITY (t) = 0;
2935   TREE_OPERAND (t, 0) = node;
2936   TREE_BLOCK (t) = NULL_TREE;
2937   if (node && !TYPE_P (node))
2938     {
2939       TREE_SIDE_EFFECTS (t) = TREE_SIDE_EFFECTS (node);
2940       TREE_READONLY (t) = TREE_READONLY (node);
2941     }
2942
2943   if (TREE_CODE_CLASS (code) == tcc_statement)
2944     TREE_SIDE_EFFECTS (t) = 1;
2945   else switch (code)
2946     {
2947     case VA_ARG_EXPR:
2948       /* All of these have side-effects, no matter what their
2949          operands are.  */
2950       TREE_SIDE_EFFECTS (t) = 1;
2951       TREE_READONLY (t) = 0;
2952       break;
2953
2954     case MISALIGNED_INDIRECT_REF:
2955     case ALIGN_INDIRECT_REF:
2956     case INDIRECT_REF:
2957       /* Whether a dereference is readonly has nothing to do with whether
2958          its operand is readonly.  */
2959       TREE_READONLY (t) = 0;
2960       break;
2961
2962     case ADDR_EXPR:
2963       if (node)
2964         recompute_tree_invariant_for_addr_expr (t);
2965       break;
2966
2967     default:
2968       if ((TREE_CODE_CLASS (code) == tcc_unary || code == VIEW_CONVERT_EXPR)
2969           && node && !TYPE_P (node)
2970           && TREE_CONSTANT (node))
2971         TREE_CONSTANT (t) = 1;
2972       if ((TREE_CODE_CLASS (code) == tcc_unary || code == VIEW_CONVERT_EXPR)
2973           && node && TREE_INVARIANT (node))
2974         TREE_INVARIANT (t) = 1;
2975       if (TREE_CODE_CLASS (code) == tcc_reference
2976           && node && TREE_THIS_VOLATILE (node))
2977         TREE_THIS_VOLATILE (t) = 1;
2978       break;
2979     }
2980
2981   return t;
2982 }
2983
2984 #define PROCESS_ARG(N)                  \
2985   do {                                  \
2986     TREE_OPERAND (t, N) = arg##N;       \
2987     if (arg##N &&!TYPE_P (arg##N))      \
2988       {                                 \
2989         if (TREE_SIDE_EFFECTS (arg##N)) \
2990           side_effects = 1;             \
2991         if (!TREE_READONLY (arg##N))    \
2992           read_only = 0;                \
2993         if (!TREE_CONSTANT (arg##N))    \
2994           constant = 0;                 \
2995         if (!TREE_INVARIANT (arg##N))   \
2996           invariant = 0;                \
2997       }                                 \
2998   } while (0)
2999
3000 tree
3001 build2_stat (enum tree_code code, tree tt, tree arg0, tree arg1 MEM_STAT_DECL)
3002 {
3003   bool constant, read_only, side_effects, invariant;
3004   tree t;
3005
3006   gcc_assert (TREE_CODE_LENGTH (code) == 2);
3007
3008   if (code == MODIFY_EXPR && cfun && cfun->gimplified)
3009     {
3010       /* We should be talking GIMPLE_MODIFY_STMT by now.  */
3011       gcc_unreachable ();
3012     }
3013
3014   /* FIXME tuples: For now let's be lazy; later we must rewrite all
3015      build2 calls to build2_gimple calls.  */
3016   if (TREE_CODE_CLASS (code) == tcc_gimple_stmt)
3017     return build2_gimple (code, arg0, arg1);
3018
3019   t = make_node_stat (code PASS_MEM_STAT);
3020   TREE_TYPE (t) = tt;
3021
3022   /* Below, we automatically set TREE_SIDE_EFFECTS and TREE_READONLY for the
3023      result based on those same flags for the arguments.  But if the
3024      arguments aren't really even `tree' expressions, we shouldn't be trying
3025      to do this.  */
3026
3027   /* Expressions without side effects may be constant if their
3028      arguments are as well.  */
3029   constant = (TREE_CODE_CLASS (code) == tcc_comparison
3030               || TREE_CODE_CLASS (code) == tcc_binary);
3031   read_only = 1;
3032   side_effects = TREE_SIDE_EFFECTS (t);
3033   invariant = constant;
3034
3035   PROCESS_ARG(0);
3036   PROCESS_ARG(1);
3037
3038   TREE_READONLY (t) = read_only;
3039   TREE_CONSTANT (t) = constant;
3040   TREE_INVARIANT (t) = invariant;
3041   TREE_SIDE_EFFECTS (t) = side_effects;
3042   TREE_THIS_VOLATILE (t)
3043     = (TREE_CODE_CLASS (code) == tcc_reference
3044        && arg0 && TREE_THIS_VOLATILE (arg0));
3045
3046   return t;
3047 }
3048
3049
3050 /* Similar as build2_stat, but for GIMPLE tuples.  For convenience's sake,
3051    arguments and return type are trees.  */
3052
3053 tree
3054 build2_gimple_stat (enum tree_code code, tree arg0, tree arg1 MEM_STAT_DECL)
3055 {
3056   bool side_effects;
3057   tree t;
3058
3059   gcc_assert (TREE_CODE_LENGTH (code) == 2);
3060
3061   t = make_node_stat (code PASS_MEM_STAT);
3062
3063   side_effects = TREE_SIDE_EFFECTS (t);
3064
3065   /* ?? We don't care about setting flags for tuples...  */
3066   GIMPLE_STMT_OPERAND (t, 0) = arg0;
3067   GIMPLE_STMT_OPERAND (t, 1) = arg1;
3068
3069   /* ...except perhaps side_effects and volatility.  ?? */
3070   TREE_SIDE_EFFECTS (t) = side_effects;
3071   TREE_THIS_VOLATILE (t) = (TREE_CODE_CLASS (code) == tcc_reference
3072                             && arg0 && TREE_THIS_VOLATILE (arg0));
3073
3074
3075   return t;
3076 }
3077
3078 tree
3079 build3_stat (enum tree_code code, tree tt, tree arg0, tree arg1,
3080              tree arg2 MEM_STAT_DECL)
3081 {
3082   bool constant, read_only, side_effects, invariant;
3083   tree t;
3084
3085   gcc_assert (TREE_CODE_LENGTH (code) == 3);
3086
3087   t = make_node_stat (code PASS_MEM_STAT);
3088   TREE_TYPE (t) = tt;
3089
3090   side_effects = TREE_SIDE_EFFECTS (t);
3091
3092   PROCESS_ARG(0);
3093   PROCESS_ARG(1);
3094   PROCESS_ARG(2);
3095
3096   if (code == CALL_EXPR && !side_effects)
3097     {
3098       tree node;
3099       int i;
3100
3101       /* Calls have side-effects, except those to const or
3102          pure functions.  */
3103       i = call_expr_flags (t);
3104       if (!(i & (ECF_CONST | ECF_PURE)))
3105         side_effects = 1;
3106
3107       /* And even those have side-effects if their arguments do.  */
3108       else for (node = arg1; node; node = TREE_CHAIN (node))
3109         if (TREE_SIDE_EFFECTS (TREE_VALUE (node)))
3110           {
3111             side_effects = 1;
3112             break;
3113           }
3114     }
3115
3116   TREE_SIDE_EFFECTS (t) = side_effects;
3117   TREE_THIS_VOLATILE (t)
3118     = (TREE_CODE_CLASS (code) == tcc_reference
3119        && arg0 && TREE_THIS_VOLATILE (arg0));
3120
3121   return t;
3122 }
3123
3124 tree
3125 build4_stat (enum tree_code code, tree tt, tree arg0, tree arg1,
3126              tree arg2, tree arg3 MEM_STAT_DECL)
3127 {
3128   bool constant, read_only, side_effects, invariant;
3129   tree t;
3130
3131   gcc_assert (TREE_CODE_LENGTH (code) == 4);
3132
3133   t = make_node_stat (code PASS_MEM_STAT);
3134   TREE_TYPE (t) = tt;
3135
3136   side_effects = TREE_SIDE_EFFECTS (t);
3137
3138   PROCESS_ARG(0);
3139   PROCESS_ARG(1);
3140   PROCESS_ARG(2);
3141   PROCESS_ARG(3);
3142
3143   TREE_SIDE_EFFECTS (t) = side_effects;
3144   TREE_THIS_VOLATILE (t)
3145     = (TREE_CODE_CLASS (code) == tcc_reference
3146        && arg0 && TREE_THIS_VOLATILE (arg0));
3147
3148   return t;
3149 }
3150
3151 tree
3152 build5_stat (enum tree_code code, tree tt, tree arg0, tree arg1,
3153              tree arg2, tree arg3, tree arg4 MEM_STAT_DECL)
3154 {
3155   bool constant, read_only, side_effects, invariant;
3156   tree t;
3157
3158   gcc_assert (TREE_CODE_LENGTH (code) == 5);
3159
3160   t = make_node_stat (code PASS_MEM_STAT);
3161   TREE_TYPE (t) = tt;
3162
3163   side_effects = TREE_SIDE_EFFECTS (t);
3164
3165   PROCESS_ARG(0);
3166   PROCESS_ARG(1);
3167   PROCESS_ARG(2);
3168   PROCESS_ARG(3);
3169   PROCESS_ARG(4);
3170
3171   TREE_SIDE_EFFECTS (t) = side_effects;
3172   TREE_THIS_VOLATILE (t)
3173     = (TREE_CODE_CLASS (code) == tcc_reference
3174        && arg0 && TREE_THIS_VOLATILE (arg0));
3175
3176   return t;
3177 }
3178
3179 tree
3180 build7_stat (enum tree_code code, tree tt, tree arg0, tree arg1,
3181              tree arg2, tree arg3, tree arg4, tree arg5,
3182              tree arg6 MEM_STAT_DECL)
3183 {
3184   bool constant, read_only, side_effects, invariant;
3185   tree t;
3186
3187   gcc_assert (code == TARGET_MEM_REF);
3188
3189   t = make_node_stat (code PASS_MEM_STAT);
3190   TREE_TYPE (t) = tt;
3191
3192   side_effects = TREE_SIDE_EFFECTS (t);
3193
3194   PROCESS_ARG(0);
3195   PROCESS_ARG(1);
3196   PROCESS_ARG(2);
3197   PROCESS_ARG(3);
3198   PROCESS_ARG(4);
3199   PROCESS_ARG(5);
3200   PROCESS_ARG(6);
3201
3202   TREE_SIDE_EFFECTS (t) = side_effects;
3203   TREE_THIS_VOLATILE (t) = 0;
3204
3205   return t;
3206 }
3207
3208 /* Similar except don't specify the TREE_TYPE
3209    and leave the TREE_SIDE_EFFECTS as 0.
3210    It is permissible for arguments to be null,
3211    or even garbage if their values do not matter.  */
3212
3213 tree
3214 build_nt (enum tree_code code, ...)
3215 {
3216   tree t;
3217   int length;
3218   int i;
3219   va_list p;
3220
3221   va_start (p, code);
3222
3223   t = make_node (code);
3224   length = TREE_CODE_LENGTH (code);
3225
3226   for (i = 0; i < length; i++)
3227     TREE_OPERAND (t, i) = va_arg (p, tree);
3228
3229   va_end (p);
3230   return t;
3231 }
3232 \f
3233 /* Create a DECL_... node of code CODE, name NAME and data type TYPE.
3234    We do NOT enter this node in any sort of symbol table.
3235
3236    layout_decl is used to set up the decl's storage layout.
3237    Other slots are initialized to 0 or null pointers.  */
3238
3239 tree
3240 build_decl_stat (enum tree_code code, tree name, tree type MEM_STAT_DECL)
3241 {
3242   tree t;
3243
3244   t = make_node_stat (code PASS_MEM_STAT);
3245
3246 /*  if (type == error_mark_node)
3247     type = integer_type_node; */
3248 /* That is not done, deliberately, so that having error_mark_node
3249    as the type can suppress useless errors in the use of this variable.  */
3250
3251   DECL_NAME (t) = name;
3252   TREE_TYPE (t) = type;
3253
3254   if (code == VAR_DECL || code == PARM_DECL || code == RESULT_DECL)
3255     layout_decl (t, 0);
3256   else if (code == FUNCTION_DECL)
3257     DECL_MODE (t) = FUNCTION_MODE;
3258
3259   return t;
3260 }
3261
3262 /* Builds and returns function declaration with NAME and TYPE.  */
3263
3264 tree
3265 build_fn_decl (const char *name, tree type)
3266 {
3267   tree id = get_identifier (name);
3268   tree decl = build_decl (FUNCTION_DECL, id, type);
3269
3270   DECL_EXTERNAL (decl) = 1;
3271   TREE_PUBLIC (decl) = 1;
3272   DECL_ARTIFICIAL (decl) = 1;
3273   TREE_NOTHROW (decl) = 1;
3274
3275   return decl;
3276 }
3277
3278 \f
3279 /* BLOCK nodes are used to represent the structure of binding contours
3280    and declarations, once those contours have been exited and their contents
3281    compiled.  This information is used for outputting debugging info.  */
3282
3283 tree
3284 build_block (tree vars, tree subblocks, tree supercontext, tree chain)
3285 {
3286   tree block = make_node (BLOCK);
3287
3288   BLOCK_VARS (block) = vars;
3289   BLOCK_SUBBLOCKS (block) = subblocks;
3290   BLOCK_SUPERCONTEXT (block) = supercontext;
3291   BLOCK_CHAIN (block) = chain;
3292   return block;
3293 }
3294
3295 #if 1 /* ! defined(USE_MAPPED_LOCATION) */
3296 /* ??? gengtype doesn't handle conditionals */
3297 static GTY(()) source_locus last_annotated_node;
3298 #endif
3299
3300 #ifdef USE_MAPPED_LOCATION
3301
3302 expanded_location
3303 expand_location (source_location loc)
3304 {
3305   expanded_location xloc;
3306   if (loc == 0)
3307     {
3308       xloc.file = NULL;
3309       xloc.line = 0;
3310       xloc.column = 0;
3311     }
3312   else
3313     {
3314       const struct line_map *map = linemap_lookup (&line_table, loc);
3315       xloc.file = map->to_file;
3316       xloc.line = SOURCE_LINE (map, loc);
3317       xloc.column = SOURCE_COLUMN (map, loc);
3318     };
3319   return xloc;
3320 }
3321
3322 #else
3323
3324 /* Record the exact location where an expression or an identifier were
3325    encountered.  */
3326
3327 void
3328 annotate_with_file_line (tree node, const char *file, int line)
3329 {
3330   /* Roughly one percent of the calls to this function are to annotate
3331      a node with the same information already attached to that node!
3332      Just return instead of wasting memory.  */
3333   if (EXPR_LOCUS (node)
3334       && EXPR_LINENO (node) == line
3335       && (EXPR_FILENAME (node) == file
3336           || !strcmp (EXPR_FILENAME (node), file)))
3337     {
3338       last_annotated_node = EXPR_LOCUS (node);
3339       return;
3340     }
3341
3342   /* In heavily macroized code (such as GCC itself) this single
3343      entry cache can reduce the number of allocations by more
3344      than half.  */
3345   if (last_annotated_node
3346       && last_annotated_node->line == line
3347       && (last_annotated_node->file == file
3348           || !strcmp (last_annotated_node->file, file)))
3349     {
3350       SET_EXPR_LOCUS (node, last_annotated_node);
3351       return;
3352     }
3353
3354   SET_EXPR_LOCUS (node, ggc_alloc (sizeof (location_t)));
3355   EXPR_LINENO (node) = line;
3356   EXPR_FILENAME (node) = file;
3357   last_annotated_node = EXPR_LOCUS (node);
3358 }
3359
3360 void
3361 annotate_with_locus (tree node, location_t locus)
3362 {
3363   annotate_with_file_line (node, locus.file, locus.line);
3364 }
3365 #endif
3366 \f
3367 /* Source location accessor functions.  */
3368
3369
3370 /* The source location of this expression.  Non-tree_exp nodes such as
3371    decls and constants can be shared among multiple locations, so
3372    return nothing.  */
3373 location_t
3374 expr_location (tree node)
3375 {
3376 #ifdef USE_MAPPED_LOCATION
3377   if (GIMPLE_STMT_P (node))
3378     return GIMPLE_STMT_LOCUS (node);
3379   return EXPR_P (node) ? node->exp.locus : UNKNOWN_LOCATION;
3380 #else
3381   if (GIMPLE_STMT_P (node))
3382     return EXPR_HAS_LOCATION (node)
3383       ? *GIMPLE_STMT_LOCUS (node) : UNKNOWN_LOCATION;
3384   return EXPR_HAS_LOCATION (node) ? *node->exp.locus : UNKNOWN_LOCATION;
3385 #endif
3386 }
3387
3388 void
3389 set_expr_location (tree node, location_t locus)
3390 {
3391 #ifdef USE_MAPPED_LOCATION
3392   if (GIMPLE_STMT_P (node))
3393     GIMPLE_STMT_LOCUS (node) = locus;
3394   else
3395     EXPR_CHECK (node)->exp.locus = locus;
3396 #else
3397       annotate_with_locus (node, locus);
3398 #endif
3399 }
3400
3401 bool
3402 expr_has_location (tree node)
3403 {
3404 #ifdef USE_MAPPED_LOCATION
3405   return expr_location (node) != UNKNOWN_LOCATION;
3406 #else
3407   return expr_locus (node) != NULL;
3408 #endif
3409 }
3410
3411 #ifdef USE_MAPPED_LOCATION
3412 source_location *
3413 #else
3414 source_locus
3415 #endif
3416 expr_locus (tree node)
3417 {
3418 #ifdef USE_MAPPED_LOCATION
3419   if (GIMPLE_STMT_P (node))
3420     return &GIMPLE_STMT_LOCUS (node);
3421   return EXPR_P (node) ? &node->exp.locus : (location_t *) NULL;
3422 #else
3423   if (GIMPLE_STMT_P (node))
3424     return GIMPLE_STMT_LOCUS (node);
3425   /* ?? The cast below was originally "(location_t *)" in the macro,
3426      but that makes no sense.  ?? */
3427   return EXPR_P (node) ? node->exp.locus : (source_locus) NULL;
3428 #endif
3429 }
3430
3431 void
3432 set_expr_locus (tree node,
3433 #ifdef USE_MAPPED_LOCATION
3434                 source_location *loc
3435 #else
3436                 source_locus loc
3437 #endif
3438                 )
3439 {
3440 #ifdef USE_MAPPED_LOCATION
3441   if (loc == NULL)
3442     {
3443       if (GIMPLE_STMT_P (node))
3444         GIMPLE_STMT_LOCUS (node) = UNKNOWN_LOCATION;
3445       else
3446         EXPR_CHECK (node)->exp.locus = UNKNOWN_LOCATION;
3447     }
3448   else
3449     {
3450       if (GIMPLE_STMT_P (node))
3451         GIMPLE_STMT_LOCUS (node) = *loc;
3452       else
3453         EXPR_CHECK (node)->exp.locus = *loc;
3454     }
3455 #else
3456   if (GIMPLE_STMT_P (node))
3457     GIMPLE_STMT_LOCUS (node) = loc;
3458   else
3459     EXPR_CHECK (node)->exp.locus = loc;
3460 #endif
3461 }
3462
3463 const char **
3464 expr_filename (tree node)
3465 {
3466 #ifdef USE_MAPPED_LOCATION
3467   if (GIMPLE_STMT_P (node))
3468     return &LOCATION_FILE (GIMPLE_STMT_LOCUS (node));
3469   return &LOCATION_FILE (EXPR_CHECK (node)->exp.locus);
3470 #else
3471   if (GIMPLE_STMT_P (node))
3472     return &GIMPLE_STMT_LOCUS (node)->file;
3473   return &(EXPR_CHECK (node)->exp.locus->file);
3474 #endif
3475 }
3476
3477 int *
3478 expr_lineno (tree node)
3479 {
3480 #ifdef USE_MAPPED_LOCATION
3481   if (GIMPLE_STMT_P (node))
3482     return &LOCATION_LINE (GIMPLE_STMT_LOCUS (node));
3483   return &LOCATION_LINE (EXPR_CHECK (node)->exp.locus);
3484 #else
3485   if (GIMPLE_STMT_P (node))
3486     return &GIMPLE_STMT_LOCUS (node)->line;
3487   return &EXPR_CHECK (node)->exp.locus->line;
3488 #endif
3489 }
3490 \f
3491 /* Return a declaration like DDECL except that its DECL_ATTRIBUTES
3492    is ATTRIBUTE.  */
3493
3494 tree
3495 build_decl_attribute_variant (tree ddecl, tree attribute)
3496 {
3497   DECL_ATTRIBUTES (ddecl) = attribute;
3498   return ddecl;
3499 }
3500
3501 /* Borrowed from hashtab.c iterative_hash implementation.  */
3502 #define mix(a,b,c) \
3503 { \
3504   a -= b; a -= c; a ^= (c>>13); \
3505   b -= c; b -= a; b ^= (a<< 8); \
3506   c -= a; c -= b; c ^= ((b&0xffffffff)>>13); \
3507   a -= b; a -= c; a ^= ((c&0xffffffff)>>12); \
3508   b -= c; b -= a; b = (b ^ (a<<16)) & 0xffffffff; \
3509   c -= a; c -= b; c = (c ^ (b>> 5)) & 0xffffffff; \
3510   a -= b; a -= c; a = (a ^ (c>> 3)) & 0xffffffff; \
3511   b -= c; b -= a; b = (b ^ (a<<10)) & 0xffffffff; \
3512   c -= a; c -= b; c = (c ^ (b>>15)) & 0xffffffff; \
3513 }
3514
3515
3516 /* Produce good hash value combining VAL and VAL2.  */
3517 static inline hashval_t
3518 iterative_hash_hashval_t (hashval_t val, hashval_t val2)
3519 {
3520   /* the golden ratio; an arbitrary value.  */
3521   hashval_t a = 0x9e3779b9;
3522
3523   mix (a, val, val2);
3524   return val2;
3525 }
3526
3527 /* Produce good hash value combining PTR and VAL2.  */
3528 static inline hashval_t
3529 iterative_hash_pointer (void *ptr, hashval_t val2)
3530 {
3531   if (sizeof (ptr) == sizeof (hashval_t))
3532     return iterative_hash_hashval_t ((size_t) ptr, val2);
3533   else
3534     {
3535       hashval_t a = (hashval_t) (size_t) ptr;
3536       /* Avoid warnings about shifting of more than the width of the type on
3537          hosts that won't execute this path.  */
3538       int zero = 0;
3539       hashval_t b = (hashval_t) ((size_t) ptr >> (sizeof (hashval_t) * 8 + zero));
3540       mix (a, b, val2);
3541       return val2;
3542     }
3543 }
3544
3545 /* Produce good hash value combining VAL and VAL2.  */
3546 static inline hashval_t
3547 iterative_hash_host_wide_int (HOST_WIDE_INT val, hashval_t val2)
3548 {
3549   if (sizeof (HOST_WIDE_INT) == sizeof (hashval_t))
3550     return iterative_hash_hashval_t (val, val2);
3551   else
3552     {
3553       hashval_t a = (hashval_t) val;
3554       /* Avoid warnings about shifting of more than the width of the type on
3555          hosts that won't execute this path.  */
3556       int zero = 0;
3557       hashval_t b = (hashval_t) (val >> (sizeof (hashval_t) * 8 + zero));
3558       mix (a, b, val2);
3559       if (sizeof (HOST_WIDE_INT) > 2 * sizeof (hashval_t))
3560         {
3561           hashval_t a = (hashval_t) (val >> (sizeof (hashval_t) * 16 + zero));
3562           hashval_t b = (hashval_t) (val >> (sizeof (hashval_t) * 24 + zero));
3563           mix (a, b, val2);
3564         }
3565       return val2;
3566     }
3567 }
3568
3569 /* Return a type like TTYPE except that its TYPE_ATTRIBUTE
3570    is ATTRIBUTE and its qualifiers are QUALS.
3571
3572    Record such modified types already made so we don't make duplicates.  */
3573
3574 static tree
3575 build_type_attribute_qual_variant (tree ttype, tree attribute, int quals)
3576 {
3577   if (! attribute_list_equal (TYPE_ATTRIBUTES (ttype), attribute))
3578     {
3579       hashval_t hashcode = 0;
3580       tree ntype;
3581       enum tree_code code = TREE_CODE (ttype);
3582
3583       ntype = copy_node (ttype);
3584
3585       TYPE_POINTER_TO (ntype) = 0;
3586       TYPE_REFERENCE_TO (ntype) = 0;
3587       TYPE_ATTRIBUTES (ntype) = attribute;
3588
3589       if (TYPE_STRUCTURAL_EQUALITY_P (ttype))
3590         SET_TYPE_STRUCTURAL_EQUALITY (ntype);
3591       else
3592         TYPE_CANONICAL (ntype)
3593           = build_qualified_type (TYPE_CANONICAL (ttype), quals);
3594
3595       /* Create a new main variant of TYPE.  */
3596       TYPE_MAIN_VARIANT (ntype) = ntype;
3597       TYPE_NEXT_VARIANT (ntype) = 0;
3598       set_type_quals (ntype, TYPE_UNQUALIFIED);
3599
3600       hashcode = iterative_hash_object (code, hashcode);
3601       if (TREE_TYPE (ntype))
3602         hashcode = iterative_hash_object (TYPE_HASH (TREE_TYPE (ntype)),
3603                                           hashcode);
3604       hashcode = attribute_hash_list (attribute, hashcode);
3605
3606       switch (TREE_CODE (ntype))
3607         {
3608         case FUNCTION_TYPE:
3609           hashcode = type_hash_list (TYPE_ARG_TYPES (ntype), hashcode);
3610           break;
3611         case ARRAY_TYPE:
3612           hashcode = iterative_hash_object (TYPE_HASH (TYPE_DOMAIN (ntype)),
3613                                             hashcode);
3614           break;
3615         case INTEGER_TYPE:
3616           hashcode = iterative_hash_object
3617             (TREE_INT_CST_LOW (TYPE_MAX_VALUE (ntype)), hashcode);
3618           hashcode = iterative_hash_object
3619             (TREE_INT_CST_HIGH (TYPE_MAX_VALUE (ntype)), hashcode);
3620           break;
3621         case REAL_TYPE:
3622           {
3623             unsigned int precision = TYPE_PRECISION (ntype);
3624             hashcode = iterative_hash_object (precision, hashcode);
3625           }
3626           break;
3627         default:
3628           break;
3629         }
3630
3631       ntype = type_hash_canon (hashcode, ntype);
3632
3633       /* If the target-dependent attributes make NTYPE different from
3634          its canonical type, we will need to use structural equality
3635          checks for this qualified type. */
3636       if (!targetm.comp_type_attributes (ntype, ttype))
3637         SET_TYPE_STRUCTURAL_EQUALITY (ntype);
3638
3639       ttype = build_qualified_type (ntype, quals);
3640     }
3641
3642   return ttype;
3643 }
3644
3645
3646 /* Return a type like TTYPE except that its TYPE_ATTRIBUTE
3647    is ATTRIBUTE.
3648
3649    Record such modified types already made so we don't make duplicates.  */
3650
3651 tree
3652 build_type_attribute_variant (tree ttype, tree attribute)
3653 {
3654   return build_type_attribute_qual_variant (ttype, attribute,
3655                                             TYPE_QUALS (ttype));
3656 }
3657
3658 /* Return nonzero if IDENT is a valid name for attribute ATTR,
3659    or zero if not.
3660
3661    We try both `text' and `__text__', ATTR may be either one.  */
3662 /* ??? It might be a reasonable simplification to require ATTR to be only
3663    `text'.  One might then also require attribute lists to be stored in
3664    their canonicalized form.  */
3665
3666 static int
3667 is_attribute_with_length_p (const char *attr, int attr_len, tree ident)
3668 {
3669   int ident_len;
3670   const char *p;
3671
3672   if (TREE_CODE (ident) != IDENTIFIER_NODE)
3673     return 0;
3674
3675   p = IDENTIFIER_POINTER (ident);
3676   ident_len = IDENTIFIER_LENGTH (ident);
3677
3678   if (ident_len == attr_len
3679       && strcmp (attr, p) == 0)
3680     return 1;
3681
3682   /* If ATTR is `__text__', IDENT must be `text'; and vice versa.  */
3683   if (attr[0] == '_')
3684     {
3685       gcc_assert (attr[1] == '_');
3686       gcc_assert (attr[attr_len - 2] == '_');
3687       gcc_assert (attr[attr_len - 1] == '_');
3688       if (ident_len == attr_len - 4
3689           && strncmp (attr + 2, p, attr_len - 4) == 0)
3690         return 1;
3691     }
3692   else
3693     {
3694       if (ident_len == attr_len + 4
3695           && p[0] == '_' && p[1] == '_'
3696           && p[ident_len - 2] == '_' && p[ident_len - 1] == '_'
3697           && strncmp (attr, p + 2, attr_len) == 0)
3698         return 1;
3699     }
3700
3701   return 0;
3702 }
3703
3704 /* Return nonzero if IDENT is a valid name for attribute ATTR,
3705    or zero if not.
3706
3707    We try both `text' and `__text__', ATTR may be either one.  */
3708
3709 int
3710 is_attribute_p (const char *attr, tree ident)
3711 {
3712   return is_attribute_with_length_p (attr, strlen (attr), ident);
3713 }
3714
3715 /* Given an attribute name and a list of attributes, return a pointer to the
3716    attribute's list element if the attribute is part of the list, or NULL_TREE
3717    if not found.  If the attribute appears more than once, this only
3718    returns the first occurrence; the TREE_CHAIN of the return value should
3719    be passed back in if further occurrences are wanted.  */
3720
3721 tree
3722 lookup_attribute (const char *attr_name, tree list)
3723 {
3724   tree l;
3725   size_t attr_len = strlen (attr_name);
3726
3727   for (l = list; l; l = TREE_CHAIN (l))
3728     {
3729       gcc_assert (TREE_CODE (TREE_PURPOSE (l)) == IDENTIFIER_NODE);
3730       if (is_attribute_with_length_p (attr_name, attr_len, TREE_PURPOSE (l)))
3731         return l;
3732     }
3733
3734   return NULL_TREE;
3735 }
3736
3737 /* Remove any instances of attribute ATTR_NAME in LIST and return the
3738    modified list.  */
3739
3740 tree
3741 remove_attribute (const char *attr_name, tree list)
3742 {
3743   tree *p;
3744   size_t attr_len = strlen (attr_name);
3745
3746   for (p = &list; *p; )
3747     {
3748       tree l = *p;
3749       gcc_assert (TREE_CODE (TREE_PURPOSE (l)) == IDENTIFIER_NODE);
3750       if (is_attribute_with_length_p (attr_name, attr_len, TREE_PURPOSE (l)))
3751         *p = TREE_CHAIN (l);
3752       else
3753         p = &TREE_CHAIN (l);
3754     }
3755
3756   return list;
3757 }
3758
3759 /* Return an attribute list that is the union of a1 and a2.  */
3760
3761 tree
3762 merge_attributes (tree a1, tree a2)
3763 {
3764   tree attributes;
3765
3766   /* Either one unset?  Take the set one.  */
3767
3768   if ((attributes = a1) == 0)
3769     attributes = a2;
3770
3771   /* One that completely contains the other?  Take it.  */
3772
3773   else if (a2 != 0 && ! attribute_list_contained (a1, a2))
3774     {
3775       if (attribute_list_contained (a2, a1))
3776         attributes = a2;
3777       else
3778         {
3779           /* Pick the longest list, and hang on the other list.  */
3780
3781           if (list_length (a1) < list_length (a2))
3782             attributes = a2, a2 = a1;
3783
3784           for (; a2 != 0; a2 = TREE_CHAIN (a2))
3785             {
3786               tree a;
3787               for (a = lookup_attribute (IDENTIFIER_POINTER (TREE_PURPOSE (a2)),
3788                                          attributes);
3789                    a != NULL_TREE;
3790                    a = lookup_attribute (IDENTIFIER_POINTER (TREE_PURPOSE (a2)),
3791                                          TREE_CHAIN (a)))
3792                 {
3793                   if (TREE_VALUE (a) != NULL
3794                       && TREE_CODE (TREE_VALUE (a)) == TREE_LIST
3795                       && TREE_VALUE (a2) != NULL
3796                       && TREE_CODE (TREE_VALUE (a2)) == TREE_LIST)
3797                     {
3798                       if (simple_cst_list_equal (TREE_VALUE (a),
3799                                                  TREE_VALUE (a2)) == 1)
3800                         break;
3801                     }
3802                   else if (simple_cst_equal (TREE_VALUE (a),
3803                                              TREE_VALUE (a2)) == 1)
3804                     break;
3805                 }
3806               if (a == NULL_TREE)
3807                 {
3808                   a1 = copy_node (a2);
3809                   TREE_CHAIN (a1) = attributes;
3810                   attributes = a1;
3811                 }
3812             }
3813         }
3814     }
3815   return attributes;
3816 }
3817
3818 /* Given types T1 and T2, merge their attributes and return
3819   the result.  */
3820
3821 tree
3822 merge_type_attributes (tree t1, tree t2)
3823 {
3824   return merge_attributes (TYPE_ATTRIBUTES (t1),
3825                            TYPE_ATTRIBUTES (t2));
3826 }
3827
3828 /* Given decls OLDDECL and NEWDECL, merge their attributes and return
3829    the result.  */
3830
3831 tree
3832 merge_decl_attributes (tree olddecl, tree newdecl)
3833 {
3834   return merge_attributes (DECL_ATTRIBUTES (olddecl),
3835                            DECL_ATTRIBUTES (newdecl));
3836 }
3837
3838 #if TARGET_DLLIMPORT_DECL_ATTRIBUTES
3839
3840 /* Specialization of merge_decl_attributes for various Windows targets.
3841
3842    This handles the following situation:
3843
3844      __declspec (dllimport) int foo;
3845      int foo;
3846
3847    The second instance of `foo' nullifies the dllimport.  */
3848
3849 tree
3850 merge_dllimport_decl_attributes (tree old, tree new)
3851 {
3852   tree a;
3853   int delete_dllimport_p = 1;
3854
3855   /* What we need to do here is remove from `old' dllimport if it doesn't
3856      appear in `new'.  dllimport behaves like extern: if a declaration is
3857      marked dllimport and a definition appears later, then the object
3858      is not dllimport'd.  We also remove a `new' dllimport if the old list
3859      contains dllexport:  dllexport always overrides dllimport, regardless
3860      of the order of declaration.  */
3861   if (!VAR_OR_FUNCTION_DECL_P (new))
3862     delete_dllimport_p = 0;
3863   else if (DECL_DLLIMPORT_P (new)
3864            && lookup_attribute ("dllexport", DECL_ATTRIBUTES (old)))
3865     {
3866       DECL_DLLIMPORT_P (new) = 0;
3867       warning (OPT_Wattributes, "%q+D already declared with dllexport attribute: "
3868               "dllimport ignored", new);
3869     }
3870   else if (DECL_DLLIMPORT_P (old) && !DECL_DLLIMPORT_P (new))
3871     {
3872       /* Warn about overriding a symbol that has already been used. eg:
3873            extern int __attribute__ ((dllimport)) foo;
3874            int* bar () {return &foo;}
3875            int foo;
3876       */
3877       if (TREE_USED (old))
3878         {
3879           warning (0, "%q+D redeclared without dllimport attribute "
3880                    "after being referenced with dll linkage", new);
3881           /* If we have used a variable's address with dllimport linkage,
3882               keep the old DECL_DLLIMPORT_P flag: the ADDR_EXPR using the
3883               decl may already have had TREE_INVARIANT and TREE_CONSTANT
3884               computed.
3885               We still remove the attribute so that assembler code refers
3886               to '&foo rather than '_imp__foo'.  */
3887           if (TREE_CODE (old) == VAR_DECL && TREE_ADDRESSABLE (old))
3888             DECL_DLLIMPORT_P (new) = 1;
3889         }
3890
3891       /* Let an inline definition silently override the external reference,
3892          but otherwise warn about attribute inconsistency.  */
3893       else if (TREE_CODE (new) == VAR_DECL
3894                || !DECL_DECLARED_INLINE_P (new))
3895         warning (OPT_Wattributes, "%q+D redeclared without dllimport attribute: "
3896                   "previous dllimport ignored", new);
3897     }
3898   else
3899     delete_dllimport_p = 0;
3900
3901   a = merge_attributes (DECL_ATTRIBUTES (old), DECL_ATTRIBUTES (new));
3902
3903   if (delete_dllimport_p)
3904     {
3905       tree prev, t;
3906       const size_t attr_len = strlen ("dllimport");
3907
3908       /* Scan the list for dllimport and delete it.  */
3909       for (prev = NULL_TREE, t = a; t; prev = t, t = TREE_CHAIN (t))
3910         {
3911           if (is_attribute_with_length_p ("dllimport", attr_len,
3912                                           TREE_PURPOSE (t)))
3913             {
3914               if (prev == NULL_TREE)
3915                 a = TREE_CHAIN (a);
3916               else
3917                 TREE_CHAIN (prev) = TREE_CHAIN (t);
3918               break;
3919             }
3920         }
3921     }
3922
3923   return a;
3924 }
3925
3926 /* Handle a "dllimport" or "dllexport" attribute; arguments as in
3927    struct attribute_spec.handler.  */
3928
3929 tree
3930 handle_dll_attribute (tree * pnode, tree name, tree args, int flags,
3931                       bool *no_add_attrs)
3932 {
3933   tree node = *pnode;
3934
3935   /* These attributes may apply to structure and union types being created,
3936      but otherwise should pass to the declaration involved.  */
3937   if (!DECL_P (node))
3938     {
3939       if (flags & ((int) ATTR_FLAG_DECL_NEXT | (int) ATTR_FLAG_FUNCTION_NEXT
3940                    | (int) ATTR_FLAG_ARRAY_NEXT))
3941         {
3942           *no_add_attrs = true;
3943           return tree_cons (name, args, NULL_TREE);
3944         }
3945       if (TREE_CODE (node) != RECORD_TYPE && TREE_CODE (node) != UNION_TYPE)
3946         {
3947           warning (OPT_Wattributes, "%qs attribute ignored",
3948                    IDENTIFIER_POINTER (name));
3949           *no_add_attrs = true;
3950         }
3951
3952       return NULL_TREE;
3953     }
3954
3955   if (TREE_CODE (node) != FUNCTION_DECL
3956       && TREE_CODE (node) != VAR_DECL)
3957     {
3958       *no_add_attrs = true;
3959       warning (OPT_Wattributes, "%qs attribute ignored",
3960                IDENTIFIER_POINTER (name));
3961       return NULL_TREE;
3962     }
3963
3964   /* Report error on dllimport ambiguities seen now before they cause
3965      any damage.  */
3966   else if (is_attribute_p ("dllimport", name))
3967     {
3968       /* Honor any target-specific overrides. */
3969       if (!targetm.valid_dllimport_attribute_p (node))
3970         *no_add_attrs = true;
3971
3972      else if (TREE_CODE (node) == FUNCTION_DECL
3973                 && DECL_DECLARED_INLINE_P (node))
3974         {
3975           warning (OPT_Wattributes, "inline function %q+D declared as "
3976                   " dllimport: attribute ignored", node);
3977           *no_add_attrs = true;
3978         }
3979       /* Like MS, treat definition of dllimported variables and
3980          non-inlined functions on declaration as syntax errors. */
3981      else if (TREE_CODE (node) == FUNCTION_DECL && DECL_INITIAL (node))
3982         {
3983           error ("function %q+D definition is marked dllimport", node);
3984           *no_add_attrs = true;
3985         }
3986
3987      else if (TREE_CODE (node) == VAR_DECL)
3988         {
3989           if (DECL_INITIAL (node))
3990             {
3991               error ("variable %q+D definition is marked dllimport",
3992                      node);
3993               *no_add_attrs = true;
3994             }
3995
3996           /* `extern' needn't be specified with dllimport.
3997              Specify `extern' now and hope for the best.  Sigh.  */
3998           DECL_EXTERNAL (node) = 1;
3999           /* Also, implicitly give dllimport'd variables declared within
4000              a function global scope, unless declared static.  */
4001           if (current_function_decl != NULL_TREE && !TREE_STATIC (node))
4002             TREE_PUBLIC (node) = 1;
4003         }
4004
4005       if (*no_add_attrs == false)
4006         DECL_DLLIMPORT_P (node) = 1;
4007     }
4008
4009   /*  Report error if symbol is not accessible at global scope.  */
4010   if (!TREE_PUBLIC (node)
4011       && (TREE_CODE (node) == VAR_DECL
4012           || TREE_CODE (node) == FUNCTION_DECL))
4013     {
4014       error ("external linkage required for symbol %q+D because of "
4015              "%qs attribute", node, IDENTIFIER_POINTER (name));
4016       *no_add_attrs = true;
4017     }
4018
4019   return NULL_TREE;
4020 }
4021
4022 #endif /* TARGET_DLLIMPORT_DECL_ATTRIBUTES  */
4023 \f
4024 /* Set the type qualifiers for TYPE to TYPE_QUALS, which is a bitmask
4025    of the various TYPE_QUAL values.  */
4026
4027 static void
4028 set_type_quals (tree type, int type_quals)
4029 {
4030   TYPE_READONLY (type) = (type_quals & TYPE_QUAL_CONST) != 0;
4031   TYPE_VOLATILE (type) = (type_quals & TYPE_QUAL_VOLATILE) != 0;
4032   TYPE_RESTRICT (type) = (type_quals & TYPE_QUAL_RESTRICT) != 0;
4033 }
4034
4035 /* Returns true iff cand is equivalent to base with type_quals.  */
4036
4037 bool
4038 check_qualified_type (tree cand, tree base, int type_quals)
4039 {
4040   return (TYPE_QUALS (cand) == type_quals
4041           && TYPE_NAME (cand) == TYPE_NAME (base)
4042           /* Apparently this is needed for Objective-C.  */
4043           && TYPE_CONTEXT (cand) == TYPE_CONTEXT (base)
4044           && attribute_list_equal (TYPE_ATTRIBUTES (cand),
4045                                    TYPE_ATTRIBUTES (base)));
4046 }
4047
4048 /* Return a version of the TYPE, qualified as indicated by the
4049    TYPE_QUALS, if one exists.  If no qualified version exists yet,
4050    return NULL_TREE.  */
4051
4052 tree
4053 get_qualified_type (tree type, int type_quals)
4054 {
4055   tree t;
4056
4057   if (TYPE_QUALS (type) == type_quals)
4058     return type;
4059
4060   /* Search the chain of variants to see if there is already one there just
4061      like the one we need to have.  If so, use that existing one.  We must
4062      preserve the TYPE_NAME, since there is code that depends on this.  */
4063   for (t = TYPE_MAIN_VARIANT (type); t; t = TYPE_NEXT_VARIANT (t))
4064     if (check_qualified_type (t, type, type_quals))
4065       return t;
4066
4067   return NULL_TREE;
4068 }
4069
4070 /* Like get_qualified_type, but creates the type if it does not
4071    exist.  This function never returns NULL_TREE.  */
4072
4073 tree
4074 build_qualified_type (tree type, int type_quals)
4075 {
4076   tree t;
4077
4078   /* See if we already have the appropriate qualified variant.  */
4079   t = get_qualified_type (type, type_quals);
4080
4081   /* If not, build it.  */
4082   if (!t)
4083     {
4084       t = build_variant_type_copy (type);
4085       set_type_quals (t, type_quals);
4086
4087       if (TYPE_STRUCTURAL_EQUALITY_P (type))
4088         /* Propagate structural equality. */
4089         SET_TYPE_STRUCTURAL_EQUALITY (t);
4090       else if (TYPE_CANONICAL (type) != type)
4091         /* Build the underlying canonical type, since it is different
4092            from TYPE. */
4093         TYPE_CANONICAL (t) = build_qualified_type (TYPE_CANONICAL (type),
4094                                                    type_quals);
4095       else
4096         /* T is its own canonical type. */
4097         TYPE_CANONICAL (t) = t;
4098
4099     }
4100
4101   return t;
4102 }
4103
4104 /* Create a new distinct copy of TYPE.  The new type is made its own
4105    MAIN_VARIANT. If TYPE requires structural equality checks, the
4106    resulting type requires structural equality checks; otherwise, its
4107    TYPE_CANONICAL points to itself. */
4108
4109 tree
4110 build_distinct_type_copy (tree type)
4111 {
4112   tree t = copy_node (type);
4113
4114   TYPE_POINTER_TO (t) = 0;
4115   TYPE_REFERENCE_TO (t) = 0;
4116
4117   /* Set the canonical type either to a new equivalence class, or
4118      propagate the need for structural equality checks. */
4119   if (TYPE_STRUCTURAL_EQUALITY_P (type))
4120     SET_TYPE_STRUCTURAL_EQUALITY (t);
4121   else
4122     TYPE_CANONICAL (t) = t;
4123
4124   /* Make it its own variant.  */
4125   TYPE_MAIN_VARIANT (t) = t;
4126   TYPE_NEXT_VARIANT (t) = 0;
4127
4128   return t;
4129 }
4130
4131 /* Create a new variant of TYPE, equivalent but distinct.  This is so
4132    the caller can modify it. TYPE_CANONICAL for the return type will
4133    be equivalent to TYPE_CANONICAL of TYPE, indicating that the types
4134    are considered equal by the language itself (or that both types
4135    require structural equality checks). */
4136
4137 tree
4138 build_variant_type_copy (tree type)
4139 {
4140   tree t, m = TYPE_MAIN_VARIANT (type);
4141
4142   t = build_distinct_type_copy (type);
4143
4144   /* Since we're building a variant, assume that it is a non-semantic
4145      variant. This also propagates TYPE_STRUCTURAL_EQUALITY_P. */
4146   TYPE_CANONICAL (t) = TYPE_CANONICAL (type);
4147
4148   /* Add the new type to the chain of variants of TYPE.  */
4149   TYPE_NEXT_VARIANT (t) = TYPE_NEXT_VARIANT (m);
4150   TYPE_NEXT_VARIANT (m) = t;
4151   TYPE_MAIN_VARIANT (t) = m;
4152
4153   return t;
4154 }
4155 \f
4156 /* Return true if the from tree in both tree maps are equal.  */
4157
4158 int
4159 tree_map_eq (const void *va, const void *vb)
4160 {
4161   const struct tree_map  *a = va, *b = vb;
4162   return (a->from == b->from);
4163 }
4164
4165 /* Hash a from tree in a tree_map.  */
4166
4167 unsigned int
4168 tree_map_hash (const void *item)
4169 {
4170   return (((const struct tree_map *) item)->hash);
4171 }
4172
4173 /* Return true if this tree map structure is marked for garbage collection
4174    purposes.  We simply return true if the from tree is marked, so that this
4175    structure goes away when the from tree goes away.  */
4176
4177 int
4178 tree_map_marked_p (const void *p)
4179 {
4180   tree from = ((struct tree_map *) p)->from;
4181
4182   return ggc_marked_p (from);
4183 }
4184
4185 /* Return true if the trees in the tree_int_map *'s VA and VB are equal.  */
4186
4187 static int
4188 tree_int_map_eq (const void *va, const void *vb)
4189 {
4190   const struct tree_int_map  *a = va, *b = vb;
4191   return (a->from == b->from);
4192 }
4193
4194 /* Hash a from tree in the tree_int_map * ITEM.  */
4195
4196 static unsigned int
4197 tree_int_map_hash (const void *item)
4198 {
4199   return htab_hash_pointer (((const struct tree_int_map *)item)->from);
4200 }
4201
4202 /* Return true if this tree int map structure is marked for garbage collection
4203    purposes.  We simply return true if the from tree_int_map *P's from tree is marked, so that this
4204    structure goes away when the from tree goes away.  */
4205
4206 static int
4207 tree_int_map_marked_p (const void *p)
4208 {
4209   tree from = ((struct tree_int_map *) p)->from;
4210
4211   return ggc_marked_p (from);
4212 }
4213 /* Lookup an init priority for FROM, and return it if we find one.  */
4214
4215 unsigned short
4216 decl_init_priority_lookup (tree from)
4217 {
4218   struct tree_int_map *h, in;
4219   in.from = from;
4220
4221   h = htab_find_with_hash (init_priority_for_decl,
4222                            &in, htab_hash_pointer (from));
4223   if (h)
4224     return h->to;
4225   return 0;
4226 }
4227
4228 /* Insert a mapping FROM->TO in the init priority hashtable.  */
4229
4230 void
4231 decl_init_priority_insert (tree from, unsigned short to)
4232 {
4233   struct tree_int_map *h;
4234   void **loc;
4235
4236   h = ggc_alloc (sizeof (struct tree_int_map));
4237   h->from = from;
4238   h->to = to;
4239   loc = htab_find_slot_with_hash (init_priority_for_decl, h,
4240                                   htab_hash_pointer (from), INSERT);
4241   *(struct tree_int_map **) loc = h;
4242 }
4243
4244 /* Look up a restrict qualified base decl for FROM.  */
4245
4246 tree
4247 decl_restrict_base_lookup (tree from)
4248 {
4249   struct tree_map *h;
4250   struct tree_map in;
4251
4252   in.from = from;
4253   h = htab_find_with_hash (restrict_base_for_decl, &in,
4254                            htab_hash_pointer (from));
4255   return h ? h->to : NULL_TREE;
4256 }
4257
4258 /* Record the restrict qualified base TO for FROM.  */
4259
4260 void
4261 decl_restrict_base_insert (tree from, tree to)
4262 {
4263   struct tree_map *h;
4264   void **loc;
4265
4266   h = ggc_alloc (sizeof (struct tree_map));
4267   h->hash = htab_hash_pointer (from);
4268   h->from = from;
4269   h->to = to;
4270   loc = htab_find_slot_with_hash (restrict_base_for_decl, h, h->hash, INSERT);
4271   *(struct tree_map **) loc = h;
4272 }
4273
4274 /* Print out the statistics for the DECL_DEBUG_EXPR hash table.  */
4275
4276 static void
4277 print_debug_expr_statistics (void)
4278 {
4279   fprintf (stderr, "DECL_DEBUG_EXPR  hash: size %ld, %ld elements, %f collisions\n",
4280            (long) htab_size (debug_expr_for_decl),
4281            (long) htab_elements (debug_expr_for_decl),
4282            htab_collisions (debug_expr_for_decl));
4283 }
4284
4285 /* Print out the statistics for the DECL_VALUE_EXPR hash table.  */
4286
4287 static void
4288 print_value_expr_statistics (void)
4289 {
4290   fprintf (stderr, "DECL_VALUE_EXPR  hash: size %ld, %ld elements, %f collisions\n",
4291            (long) htab_size (value_expr_for_decl),
4292            (long) htab_elements (value_expr_for_decl),
4293            htab_collisions (value_expr_for_decl));
4294 }
4295
4296 /* Print out statistics for the RESTRICT_BASE_FOR_DECL hash table, but
4297    don't print anything if the table is empty.  */
4298
4299 static void
4300 print_restrict_base_statistics (void)
4301 {
4302   if (htab_elements (restrict_base_for_decl) != 0)
4303     fprintf (stderr,
4304              "RESTRICT_BASE    hash: size %ld, %ld elements, %f collisions\n",
4305              (long) htab_size (restrict_base_for_decl),
4306              (long) htab_elements (restrict_base_for_decl),
4307              htab_collisions (restrict_base_for_decl));
4308 }
4309
4310 /* Lookup a debug expression for FROM, and return it if we find one.  */
4311
4312 tree
4313 decl_debug_expr_lookup (tree from)
4314 {
4315   struct tree_map *h, in;
4316   in.from = from;
4317
4318   h = htab_find_with_hash (debug_expr_for_decl, &in, htab_hash_pointer (from));
4319   if (h)
4320     return h->to;
4321   return NULL_TREE;
4322 }
4323
4324 /* Insert a mapping FROM->TO in the debug expression hashtable.  */
4325
4326 void
4327 decl_debug_expr_insert (tree from, tree to)
4328 {
4329   struct tree_map *h;
4330   void **loc;
4331
4332   h = ggc_alloc (sizeof (struct tree_map));
4333   h->hash = htab_hash_pointer (from);
4334   h->from = from;
4335   h->to = to;
4336   loc = htab_find_slot_with_hash (debug_expr_for_decl, h, h->hash, INSERT);
4337   *(struct tree_map **) loc = h;
4338 }
4339
4340 /* Lookup a value expression for FROM, and return it if we find one.  */
4341
4342 tree
4343 decl_value_expr_lookup (tree from)
4344 {
4345   struct tree_map *h, in;
4346   in.from = from;
4347
4348   h = htab_find_with_hash (value_expr_for_decl, &in, htab_hash_pointer (from));
4349   if (h)
4350     return h->to;
4351   return NULL_TREE;
4352 }
4353
4354 /* Insert a mapping FROM->TO in the value expression hashtable.  */
4355
4356 void
4357 decl_value_expr_insert (tree from, tree to)
4358 {
4359   struct tree_map *h;
4360   void **loc;
4361
4362   h = ggc_alloc (sizeof (struct tree_map));
4363   h->hash = htab_hash_pointer (from);
4364   h->from = from;
4365   h->to = to;
4366   loc = htab_find_slot_with_hash (value_expr_for_decl, h, h->hash, INSERT);
4367   *(struct tree_map **) loc = h;
4368 }
4369
4370 /* Hashing of types so that we don't make duplicates.
4371    The entry point is `type_hash_canon'.  */
4372
4373 /* Compute a hash code for a list of types (chain of TREE_LIST nodes
4374    with types in the TREE_VALUE slots), by adding the hash codes
4375    of the individual types.  */
4376
4377 unsigned int
4378 type_hash_list (tree list, hashval_t hashcode)
4379 {
4380   tree tail;
4381
4382   for (tail = list; tail; tail = TREE_CHAIN (tail))
4383     if (TREE_VALUE (tail) != error_mark_node)
4384       hashcode = iterative_hash_object (TYPE_HASH (TREE_VALUE (tail)),
4385                                         hashcode);
4386
4387   return hashcode;
4388 }
4389
4390 /* These are the Hashtable callback functions.  */
4391
4392 /* Returns true iff the types are equivalent.  */
4393
4394 static int
4395 type_hash_eq (const void *va, const void *vb)
4396 {
4397   const struct type_hash *a = va, *b = vb;
4398
4399   /* First test the things that are the same for all types.  */
4400   if (a->hash != b->hash
4401       || TREE_CODE (a->type) != TREE_CODE (b->type)
4402       || TREE_TYPE (a->type) != TREE_TYPE (b->type)
4403       || !attribute_list_equal (TYPE_ATTRIBUTES (a->type),
4404                                  TYPE_ATTRIBUTES (b->type))
4405       || TYPE_ALIGN (a->type) != TYPE_ALIGN (b->type)
4406       || TYPE_MODE (a->type) != TYPE_MODE (b->type))
4407     return 0;
4408
4409   switch (TREE_CODE (a->type))
4410     {
4411     case VOID_TYPE:
4412     case COMPLEX_TYPE:
4413     case POINTER_TYPE:
4414     case REFERENCE_TYPE:
4415       return 1;
4416
4417     case VECTOR_TYPE:
4418       return TYPE_VECTOR_SUBPARTS (a->type) == TYPE_VECTOR_SUBPARTS (b->type);
4419
4420     case ENUMERAL_TYPE:
4421       if (TYPE_VALUES (a->type) != TYPE_VALUES (b->type)
4422           && !(TYPE_VALUES (a->type)
4423                && TREE_CODE (TYPE_VALUES (a->type)) == TREE_LIST
4424                && TYPE_VALUES (b->type)
4425                && TREE_CODE (TYPE_VALUES (b->type)) == TREE_LIST
4426                && type_list_equal (TYPE_VALUES (a->type),
4427                                    TYPE_VALUES (b->type))))
4428         return 0;
4429
4430       /* ... fall through ... */
4431
4432     case INTEGER_TYPE:
4433     case REAL_TYPE:
4434     case BOOLEAN_TYPE:
4435       return ((TYPE_MAX_VALUE (a->type) == TYPE_MAX_VALUE (b->type)
4436                || tree_int_cst_equal (TYPE_MAX_VALUE (a->type),
4437                                       TYPE_MAX_VALUE (b->type)))
4438               && (TYPE_MIN_VALUE (a->type) == TYPE_MIN_VALUE (b->type)
4439                   || tree_int_cst_equal (TYPE_MIN_VALUE (a->type),
4440                                          TYPE_MIN_VALUE (b->type))));
4441
4442     case OFFSET_TYPE:
4443       return TYPE_OFFSET_BASETYPE (a->type) == TYPE_OFFSET_BASETYPE (b->type);
4444
4445     case METHOD_TYPE:
4446       return (TYPE_METHOD_BASETYPE (a->type) == TYPE_METHOD_BASETYPE (b->type)
4447               && (TYPE_ARG_TYPES (a->type) == TYPE_ARG_TYPES (b->type)
4448                   || (TYPE_ARG_TYPES (a->type)
4449                       && TREE_CODE (TYPE_ARG_TYPES (a->type)) == TREE_LIST
4450                       && TYPE_ARG_TYPES (b->type)
4451                       && TREE_CODE (TYPE_ARG_TYPES (b->type)) == TREE_LIST
4452                       && type_list_equal (TYPE_ARG_TYPES (a->type),
4453                                           TYPE_ARG_TYPES (b->type)))));
4454
4455     case ARRAY_TYPE:
4456       return TYPE_DOMAIN (a->type) == TYPE_DOMAIN (b->type);
4457
4458     case RECORD_TYPE:
4459     case UNION_TYPE:
4460     case QUAL_UNION_TYPE:
4461       return (TYPE_FIELDS (a->type) == TYPE_FIELDS (b->type)
4462               || (TYPE_FIELDS (a->type)
4463                   && TREE_CODE (TYPE_FIELDS (a->type)) == TREE_LIST
4464                   && TYPE_FIELDS (b->type)
4465                   && TREE_CODE (TYPE_FIELDS (b->type)) == TREE_LIST
4466                   && type_list_equal (TYPE_FIELDS (a->type),
4467                                       TYPE_FIELDS (b->type))));
4468
4469     case FUNCTION_TYPE:
4470       return (TYPE_ARG_TYPES (a->type) == TYPE_ARG_TYPES (b->type)
4471               || (TYPE_ARG_TYPES (a->type)
4472                   && TREE_CODE (TYPE_ARG_TYPES (a->type)) == TREE_LIST
4473                   && TYPE_ARG_TYPES (b->type)
4474                   && TREE_CODE (TYPE_ARG_TYPES (b->type)) == TREE_LIST
4475                   && type_list_equal (TYPE_ARG_TYPES (a->type),
4476                                       TYPE_ARG_TYPES (b->type))));
4477
4478     default:
4479       return 0;
4480     }
4481 }
4482
4483 /* Return the cached hash value.  */
4484
4485 static hashval_t
4486 type_hash_hash (const void *item)
4487 {
4488   return ((const struct type_hash *) item)->hash;
4489 }
4490
4491 /* Look in the type hash table for a type isomorphic to TYPE.
4492    If one is found, return it.  Otherwise return 0.  */
4493
4494 tree
4495 type_hash_lookup (hashval_t hashcode, tree type)
4496 {
4497   struct type_hash *h, in;
4498
4499   /* The TYPE_ALIGN field of a type is set by layout_type(), so we
4500      must call that routine before comparing TYPE_ALIGNs.  */
4501   layout_type (type);
4502
4503   in.hash = hashcode;
4504   in.type = type;
4505
4506   h = htab_find_with_hash (type_hash_table, &in, hashcode);
4507   if (h)
4508     return h->type;
4509   return NULL_TREE;
4510 }
4511
4512 /* Add an entry to the type-hash-table
4513    for a type TYPE whose hash code is HASHCODE.  */
4514
4515 void
4516 type_hash_add (hashval_t hashcode, tree type)
4517 {
4518   struct type_hash *h;
4519   void **loc;
4520
4521   h = ggc_alloc (sizeof (struct type_hash));
4522   h->hash = hashcode;
4523   h->type = type;
4524   loc = htab_find_slot_with_hash (type_hash_table, h, hashcode, INSERT);
4525   *(struct type_hash **) loc = h;
4526 }
4527
4528 /* Given TYPE, and HASHCODE its hash code, return the canonical
4529    object for an identical type if one already exists.
4530    Otherwise, return TYPE, and record it as the canonical object.
4531
4532    To use this function, first create a type of the sort you want.
4533    Then compute its hash code from the fields of the type that
4534    make it different from other similar types.
4535    Then call this function and use the value.  */
4536
4537 tree
4538 type_hash_canon (unsigned int hashcode, tree type)
4539 {
4540   tree t1;
4541
4542   /* The hash table only contains main variants, so ensure that's what we're
4543      being passed.  */
4544   gcc_assert (TYPE_MAIN_VARIANT (type) == type);
4545
4546   if (!lang_hooks.types.hash_types)
4547     return type;
4548
4549   /* See if the type is in the hash table already.  If so, return it.
4550      Otherwise, add the type.  */
4551   t1 = type_hash_lookup (hashcode, type);
4552   if (t1 != 0)
4553     {
4554 #ifdef GATHER_STATISTICS
4555       tree_node_counts[(int) t_kind]--;
4556       tree_node_sizes[(int) t_kind] -= sizeof (struct tree_type);
4557 #endif
4558       return t1;
4559     }
4560   else
4561     {
4562       type_hash_add (hashcode, type);
4563       return type;
4564     }
4565 }
4566
4567 /* See if the data pointed to by the type hash table is marked.  We consider
4568    it marked if the type is marked or if a debug type number or symbol
4569    table entry has been made for the type.  This reduces the amount of
4570    debugging output and eliminates that dependency of the debug output on
4571    the number of garbage collections.  */
4572
4573 static int
4574 type_hash_marked_p (const void *p)
4575 {
4576   tree type = ((struct type_hash *) p)->type;
4577
4578   return ggc_marked_p (type) || TYPE_SYMTAB_POINTER (type);
4579 }
4580
4581 static void
4582 print_type_hash_statistics (void)
4583 {
4584   fprintf (stderr, "Type hash: size %ld, %ld elements, %f collisions\n",
4585            (long) htab_size (type_hash_table),
4586            (long) htab_elements (type_hash_table),
4587            htab_collisions (type_hash_table));
4588 }
4589
4590 /* Compute a hash code for a list of attributes (chain of TREE_LIST nodes
4591    with names in the TREE_PURPOSE slots and args in the TREE_VALUE slots),
4592    by adding the hash codes of the individual attributes.  */
4593
4594 unsigned int
4595 attribute_hash_list (tree list, hashval_t hashcode)
4596 {
4597   tree tail;
4598
4599   for (tail = list; tail; tail = TREE_CHAIN (tail))
4600     /* ??? Do we want to add in TREE_VALUE too? */
4601     hashcode = iterative_hash_object
4602       (IDENTIFIER_HASH_VALUE (TREE_PURPOSE (tail)), hashcode);
4603   return hashcode;
4604 }
4605
4606 /* Given two lists of attributes, return true if list l2 is
4607    equivalent to l1.  */
4608
4609 int
4610 attribute_list_equal (tree l1, tree l2)
4611 {
4612   return attribute_list_contained (l1, l2)
4613          && attribute_list_contained (l2, l1);
4614 }
4615
4616 /* Given two lists of attributes, return true if list L2 is
4617    completely contained within L1.  */
4618 /* ??? This would be faster if attribute names were stored in a canonicalized
4619    form.  Otherwise, if L1 uses `foo' and L2 uses `__foo__', the long method
4620    must be used to show these elements are equivalent (which they are).  */
4621 /* ??? It's not clear that attributes with arguments will always be handled
4622    correctly.  */
4623
4624 int
4625 attribute_list_contained (tree l1, tree l2)
4626 {
4627   tree t1, t2;
4628
4629   /* First check the obvious, maybe the lists are identical.  */
4630   if (l1 == l2)
4631     return 1;
4632
4633   /* Maybe the lists are similar.  */
4634   for (t1 = l1, t2 = l2;
4635        t1 != 0 && t2 != 0
4636         && TREE_PURPOSE (t1) == TREE_PURPOSE (t2)
4637         && TREE_VALUE (t1) == TREE_VALUE (t2);
4638        t1 = TREE_CHAIN (t1), t2 = TREE_CHAIN (t2));
4639
4640   /* Maybe the lists are equal.  */
4641   if (t1 == 0 && t2 == 0)
4642     return 1;
4643
4644   for (; t2 != 0; t2 = TREE_CHAIN (t2))
4645     {
4646       tree attr;
4647       for (attr = lookup_attribute (IDENTIFIER_POINTER (TREE_PURPOSE (t2)), l1);
4648            attr != NULL_TREE;
4649            attr = lookup_attribute (IDENTIFIER_POINTER (TREE_PURPOSE (t2)),
4650                                     TREE_CHAIN (attr)))
4651         {
4652           if (TREE_VALUE (t2) != NULL
4653               && TREE_CODE (TREE_VALUE (t2)) == TREE_LIST
4654               && TREE_VALUE (attr) != NULL
4655               && TREE_CODE (TREE_VALUE (attr)) == TREE_LIST)
4656             {
4657               if (simple_cst_list_equal (TREE_VALUE (t2),
4658                                          TREE_VALUE (attr)) == 1)
4659                 break;
4660             }
4661           else if (simple_cst_equal (TREE_VALUE (t2), TREE_VALUE (attr)) == 1)
4662             break;
4663         }
4664
4665       if (attr == 0)
4666         return 0;
4667     }
4668
4669   return 1;
4670 }
4671
4672 /* Given two lists of types
4673    (chains of TREE_LIST nodes with types in the TREE_VALUE slots)
4674    return 1 if the lists contain the same types in the same order.
4675    Also, the TREE_PURPOSEs must match.  */
4676
4677 int
4678 type_list_equal (tree l1, tree l2)
4679 {
4680   tree t1, t2;
4681
4682   for (t1 = l1, t2 = l2; t1 && t2; t1 = TREE_CHAIN (t1), t2 = TREE_CHAIN (t2))
4683     if (TREE_VALUE (t1) != TREE_VALUE (t2)
4684         || (TREE_PURPOSE (t1) != TREE_PURPOSE (t2)
4685             && ! (1 == simple_cst_equal (TREE_PURPOSE (t1), TREE_PURPOSE (t2))
4686                   && (TREE_TYPE (TREE_PURPOSE (t1))
4687                       == TREE_TYPE (TREE_PURPOSE (t2))))))
4688       return 0;
4689
4690   return t1 == t2;
4691 }
4692
4693 /* Returns the number of arguments to the FUNCTION_TYPE or METHOD_TYPE
4694    given by TYPE.  If the argument list accepts variable arguments,
4695    then this function counts only the ordinary arguments.  */
4696
4697 int
4698 type_num_arguments (tree type)
4699 {
4700   int i = 0;
4701   tree t;
4702
4703   for (t = TYPE_ARG_TYPES (type); t; t = TREE_CHAIN (t))
4704     /* If the function does not take a variable number of arguments,
4705        the last element in the list will have type `void'.  */
4706     if (VOID_TYPE_P (TREE_VALUE (t)))
4707       break;
4708     else
4709       ++i;
4710
4711   return i;
4712 }
4713
4714 /* Nonzero if integer constants T1 and T2
4715    represent the same constant value.  */
4716
4717 int
4718 tree_int_cst_equal (tree t1, tree t2)
4719 {
4720   if (t1 == t2)
4721     return 1;
4722
4723   if (t1 == 0 || t2 == 0)
4724     return 0;
4725
4726   if (TREE_CODE (t1) == INTEGER_CST
4727       && TREE_CODE (t2) == INTEGER_CST
4728       && TREE_INT_CST_LOW (t1) == TREE_INT_CST_LOW (t2)
4729       && TREE_INT_CST_HIGH (t1) == TREE_INT_CST_HIGH (t2))
4730     return 1;
4731
4732   return 0;
4733 }
4734
4735 /* Nonzero if integer constants T1 and T2 represent values that satisfy <.
4736    The precise way of comparison depends on their data type.  */
4737
4738 int
4739 tree_int_cst_lt (tree t1, tree t2)
4740 {
4741   if (t1 == t2)
4742     return 0;
4743
4744   if (TYPE_UNSIGNED (TREE_TYPE (t1)) != TYPE_UNSIGNED (TREE_TYPE (t2)))
4745     {
4746       int t1_sgn = tree_int_cst_sgn (t1);
4747       int t2_sgn = tree_int_cst_sgn (t2);
4748
4749       if (t1_sgn < t2_sgn)
4750         return 1;
4751       else if (t1_sgn > t2_sgn)
4752         return 0;
4753       /* Otherwise, both are non-negative, so we compare them as
4754          unsigned just in case one of them would overflow a signed
4755          type.  */
4756     }
4757   else if (!TYPE_UNSIGNED (TREE_TYPE (t1)))
4758     return INT_CST_LT (t1, t2);
4759
4760   return INT_CST_LT_UNSIGNED (t1, t2);
4761 }
4762
4763 /* Returns -1 if T1 < T2, 0 if T1 == T2, and 1 if T1 > T2.  */
4764
4765 int
4766 tree_int_cst_compare (tree t1, tree t2)
4767 {
4768   if (tree_int_cst_lt (t1, t2))
4769     return -1;
4770   else if (tree_int_cst_lt (t2, t1))
4771     return 1;
4772   else
4773     return 0;
4774 }
4775
4776 /* Return 1 if T is an INTEGER_CST that can be manipulated efficiently on
4777    the host.  If POS is zero, the value can be represented in a single
4778    HOST_WIDE_INT.  If POS is nonzero, the value must be non-negative and can
4779    be represented in a single unsigned HOST_WIDE_INT.  */
4780
4781 int
4782 host_integerp (tree t, int pos)
4783 {
4784   return (TREE_CODE (t) == INTEGER_CST
4785           && ((TREE_INT_CST_HIGH (t) == 0
4786                && (HOST_WIDE_INT) TREE_INT_CST_LOW (t) >= 0)
4787               || (! pos && TREE_INT_CST_HIGH (t) == -1
4788                   && (HOST_WIDE_INT) TREE_INT_CST_LOW (t) < 0
4789                   && !TYPE_UNSIGNED (TREE_TYPE (t)))
4790               || (pos && TREE_INT_CST_HIGH (t) == 0)));
4791 }
4792
4793 /* Return the HOST_WIDE_INT least significant bits of T if it is an
4794    INTEGER_CST and there is no overflow.  POS is nonzero if the result must
4795    be non-negative.  We must be able to satisfy the above conditions.  */
4796
4797 HOST_WIDE_INT
4798 tree_low_cst (tree t, int pos)
4799 {
4800   gcc_assert (host_integerp (t, pos));
4801   return TREE_INT_CST_LOW (t);
4802 }
4803
4804 /* Return the most significant bit of the integer constant T.  */
4805
4806 int
4807 tree_int_cst_msb (tree t)
4808 {
4809   int prec;
4810   HOST_WIDE_INT h;
4811   unsigned HOST_WIDE_INT l;
4812
4813   /* Note that using TYPE_PRECISION here is wrong.  We care about the
4814      actual bits, not the (arbitrary) range of the type.  */
4815   prec = GET_MODE_BITSIZE (TYPE_MODE (TREE_TYPE (t))) - 1;
4816   rshift_double (TREE_INT_CST_LOW (t), TREE_INT_CST_HIGH (t), prec,
4817                  2 * HOST_BITS_PER_WIDE_INT, &l, &h, 0);
4818   return (l & 1) == 1;
4819 }
4820
4821 /* Return an indication of the sign of the integer constant T.
4822    The return value is -1 if T < 0, 0 if T == 0, and 1 if T > 0.
4823    Note that -1 will never be returned if T's type is unsigned.  */
4824
4825 int
4826 tree_int_cst_sgn (tree t)
4827 {
4828   if (TREE_INT_CST_LOW (t) == 0 && TREE_INT_CST_HIGH (t) == 0)
4829     return 0;
4830   else if (TYPE_UNSIGNED (TREE_TYPE (t)))
4831     return 1;
4832   else if (TREE_INT_CST_HIGH (t) < 0)
4833     return -1;
4834   else
4835     return 1;
4836 }
4837
4838 /* Compare two constructor-element-type constants.  Return 1 if the lists
4839    are known to be equal; otherwise return 0.  */
4840
4841 int
4842 simple_cst_list_equal (tree l1, tree l2)
4843 {
4844   while (l1 != NULL_TREE && l2 != NULL_TREE)
4845     {
4846       if (simple_cst_equal (TREE_VALUE (l1), TREE_VALUE (l2)) != 1)
4847         return 0;
4848
4849       l1 = TREE_CHAIN (l1);
4850       l2 = TREE_CHAIN (l2);
4851     }
4852
4853   return l1 == l2;
4854 }
4855
4856 /* Return truthvalue of whether T1 is the same tree structure as T2.
4857    Return 1 if they are the same.
4858    Return 0 if they are understandably different.
4859    Return -1 if either contains tree structure not understood by
4860    this function.  */
4861
4862 int
4863 simple_cst_equal (tree t1, tree t2)
4864 {
4865   enum tree_code code1, code2;
4866   int cmp;
4867   int i;
4868
4869   if (t1 == t2)
4870     return 1;
4871   if (t1 == 0 || t2 == 0)
4872     return 0;
4873
4874   code1 = TREE_CODE (t1);
4875   code2 = TREE_CODE (t2);
4876
4877   if (code1 == NOP_EXPR || code1 == CONVERT_EXPR || code1 == NON_LVALUE_EXPR)
4878     {
4879       if (code2 == NOP_EXPR || code2 == CONVERT_EXPR
4880           || code2 == NON_LVALUE_EXPR)
4881         return simple_cst_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0));
4882       else
4883         return simple_cst_equal (TREE_OPERAND (t1, 0), t2);
4884     }
4885
4886   else if (code2 == NOP_EXPR || code2 == CONVERT_EXPR
4887            || code2 == NON_LVALUE_EXPR)
4888     return simple_cst_equal (t1, TREE_OPERAND (t2, 0));
4889
4890   if (code1 != code2)
4891     return 0;
4892
4893   switch (code1)
4894     {
4895     case INTEGER_CST:
4896       return (TREE_INT_CST_LOW (t1) == TREE_INT_CST_LOW (t2)
4897               && TREE_INT_CST_HIGH (t1) == TREE_INT_CST_HIGH (t2));
4898
4899     case REAL_CST:
4900       return REAL_VALUES_IDENTICAL (TREE_REAL_CST (t1), TREE_REAL_CST (t2));
4901
4902     case STRING_CST:
4903       return (TREE_STRING_LENGTH (t1) == TREE_STRING_LENGTH (t2)
4904               && ! memcmp (TREE_STRING_POINTER (t1), TREE_STRING_POINTER (t2),
4905                          TREE_STRING_LENGTH (t1)));
4906
4907     case CONSTRUCTOR:
4908       {
4909         unsigned HOST_WIDE_INT idx;
4910         VEC(constructor_elt, gc) *v1 = CONSTRUCTOR_ELTS (t1);
4911         VEC(constructor_elt, gc) *v2 = CONSTRUCTOR_ELTS (t2);
4912
4913         if (VEC_length (constructor_elt, v1) != VEC_length (constructor_elt, v2))
4914           return false;
4915
4916         for (idx = 0; idx < VEC_length (constructor_elt, v1); ++idx)
4917           /* ??? Should we handle also fields here? */
4918           if (!simple_cst_equal (VEC_index (constructor_elt, v1, idx)->value,
4919                                  VEC_index (constructor_elt, v2, idx)->value))
4920             return false;
4921         return true;
4922       }
4923
4924     case SAVE_EXPR:
4925       return simple_cst_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0));
4926
4927     case CALL_EXPR:
4928       cmp = simple_cst_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0));
4929       if (cmp <= 0)
4930         return cmp;
4931       return
4932         simple_cst_list_equal (TREE_OPERAND (t1, 1), TREE_OPERAND (t2, 1));
4933
4934     case TARGET_EXPR:
4935       /* Special case: if either target is an unallocated VAR_DECL,
4936          it means that it's going to be unified with whatever the
4937          TARGET_EXPR is really supposed to initialize, so treat it
4938          as being equivalent to anything.  */
4939       if ((TREE_CODE (TREE_OPERAND (t1, 0)) == VAR_DECL
4940            && DECL_NAME (TREE_OPERAND (t1, 0)) == NULL_TREE
4941            && !DECL_RTL_SET_P (TREE_OPERAND (t1, 0)))
4942           || (TREE_CODE (TREE_OPERAND (t2, 0)) == VAR_DECL
4943               && DECL_NAME (TREE_OPERAND (t2, 0)) == NULL_TREE
4944               && !DECL_RTL_SET_P (TREE_OPERAND (t2, 0))))
4945         cmp = 1;
4946       else
4947         cmp = simple_cst_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0));
4948
4949       if (cmp <= 0)
4950         return cmp;
4951
4952       return simple_cst_equal (TREE_OPERAND (t1, 1), TREE_OPERAND (t2, 1));
4953
4954     case WITH_CLEANUP_EXPR:
4955       cmp = simple_cst_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0));
4956       if (cmp <= 0)
4957         return cmp;
4958
4959       return simple_cst_equal (TREE_OPERAND (t1, 1), TREE_OPERAND (t1, 1));
4960
4961     case COMPONENT_REF:
4962       if (TREE_OPERAND (t1, 1) == TREE_OPERAND (t2, 1))
4963         return simple_cst_equal (TREE_OPERAND (t1, 0), TREE_OPERAND (t2, 0));
4964
4965       return 0;
4966
4967     case VAR_DECL:
4968     case PARM_DECL:
4969     case CONST_DECL:
4970     case FUNCTION_DECL:
4971       return 0;
4972
4973     default:
4974       break;
4975     }
4976
4977   /* This general rule works for most tree codes.  All exceptions should be
4978      handled above.  If this is a language-specific tree code, we can't
4979      trust what might be in the operand, so say we don't know
4980      the situation.  */
4981   if ((int) code1 >= (int) LAST_AND_UNUSED_TREE_CODE)
4982     return -1;
4983
4984   switch (TREE_CODE_CLASS (code1))
4985     {
4986     case tcc_unary:
4987     case tcc_binary:
4988     case tcc_comparison:
4989     case tcc_expression:
4990     case tcc_reference:
4991     case tcc_statement:
4992       cmp = 1;
4993       for (i = 0; i < TREE_CODE_LENGTH (code1); i++)
4994         {
4995           cmp = simple_cst_equal (TREE_OPERAND (t1, i), TREE_OPERAND (t2, i));
4996           if (cmp <= 0)
4997             return cmp;
4998         }
4999
5000       return cmp;
5001
5002     default:
5003       return -1;
5004     }
5005 }
5006
5007 /* Compare the value of T, an INTEGER_CST, with U, an unsigned integer value.
5008    Return -1, 0, or 1 if the value of T is less than, equal to, or greater
5009    than U, respectively.  */
5010
5011 int
5012 compare_tree_int (tree t, unsigned HOST_WIDE_INT u)
5013 {
5014   if (tree_int_cst_sgn (t) < 0)
5015     return -1;
5016   else if (TREE_INT_CST_HIGH (t) != 0)
5017     return 1;
5018   else if (TREE_INT_CST_LOW (t) == u)
5019     return 0;
5020   else if (TREE_INT_CST_LOW (t) < u)
5021     return -1;
5022   else
5023     return 1;
5024 }
5025
5026 /* Return true if CODE represents an associative tree code.  Otherwise
5027    return false.  */
5028 bool
5029 associative_tree_code (enum tree_code code)
5030 {
5031   switch (code)
5032     {
5033     case BIT_IOR_EXPR:
5034     case BIT_AND_EXPR:
5035     case BIT_XOR_EXPR:
5036     case PLUS_EXPR:
5037     case MULT_EXPR:
5038     case MIN_EXPR:
5039     case MAX_EXPR:
5040       return true;
5041
5042     default:
5043       break;
5044     }
5045   return false;
5046 }
5047
5048 /* Return true if CODE represents a commutative tree code.  Otherwise
5049    return false.  */
5050 bool
5051 commutative_tree_code (enum tree_code code)
5052 {
5053   switch (code)
5054     {
5055     case PLUS_EXPR:
5056     case MULT_EXPR:
5057     case MIN_EXPR:
5058     case MAX_EXPR:
5059     case BIT_IOR_EXPR:
5060     case BIT_XOR_EXPR:
5061     case BIT_AND_EXPR:
5062     case NE_EXPR:
5063     case EQ_EXPR:
5064     case UNORDERED_EXPR:
5065     case ORDERED_EXPR:
5066     case UNEQ_EXPR:
5067     case LTGT_EXPR:
5068     case TRUTH_AND_EXPR:
5069     case TRUTH_XOR_EXPR:
5070     case TRUTH_OR_EXPR:
5071       return true;
5072
5073     default:
5074       break;
5075     }
5076   return false;
5077 }
5078
5079 /* Generate a hash value for an expression.  This can be used iteratively
5080    by passing a previous result as the "val" argument.
5081
5082    This function is intended to produce the same hash for expressions which
5083    would compare equal using operand_equal_p.  */
5084
5085 hashval_t
5086 iterative_hash_expr (tree t, hashval_t val)
5087 {
5088   int i;
5089   enum tree_code code;
5090   char class;
5091
5092   if (t == NULL_TREE)
5093     return iterative_hash_pointer (t, val);
5094
5095   code = TREE_CODE (t);
5096
5097   switch (code)
5098     {
5099     /* Alas, constants aren't shared, so we can't rely on pointer
5100        identity.  */
5101     case INTEGER_CST:
5102       val = iterative_hash_host_wide_int (TREE_INT_CST_LOW (t), val);
5103       return iterative_hash_host_wide_int (TREE_INT_CST_HIGH (t), val);
5104     case REAL_CST:
5105       {
5106         unsigned int val2 = real_hash (TREE_REAL_CST_PTR (t));
5107
5108         return iterative_hash_hashval_t (val2, val);
5109       }
5110     case STRING_CST:
5111       return iterative_hash (TREE_STRING_POINTER (t),
5112                              TREE_STRING_LENGTH (t), val);
5113     case COMPLEX_CST:
5114       val = iterative_hash_expr (TREE_REALPART (t), val);
5115       return iterative_hash_expr (TREE_IMAGPART (t), val);
5116     case VECTOR_CST:
5117       return iterative_hash_expr (TREE_VECTOR_CST_ELTS (t), val);
5118
5119     case SSA_NAME:
5120     case VALUE_HANDLE:
5121       /* we can just compare by pointer.  */
5122       return iterative_hash_pointer (t, val);
5123
5124     case TREE_LIST:
5125       /* A list of expressions, for a CALL_EXPR or as the elements of a
5126          VECTOR_CST.  */
5127       for (; t; t = TREE_CHAIN (t))
5128         val = iterative_hash_expr (TREE_VALUE (t), val);
5129       return val;
5130     case CONSTRUCTOR:
5131       {
5132         unsigned HOST_WIDE_INT idx;
5133         tree field, value;
5134         FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (t), idx, field, value)
5135           {
5136             val = iterative_hash_expr (field, val);
5137             val = iterative_hash_expr (value, val);
5138           }
5139         return val;
5140       }
5141     case FUNCTION_DECL:
5142       /* When referring to a built-in FUNCTION_DECL, use the
5143          __builtin__ form.  Otherwise nodes that compare equal
5144          according to operand_equal_p might get different
5145          hash codes.  */
5146       if (DECL_BUILT_IN (t))
5147         {
5148           val = iterative_hash_pointer (built_in_decls[DECL_FUNCTION_CODE (t)],
5149                                       val);
5150           return val;
5151         }
5152       /* else FALL THROUGH */
5153     default:
5154       class = TREE_CODE_CLASS (code);
5155
5156       if (class == tcc_declaration)
5157         {
5158           /* DECL's have a unique ID */
5159           val = iterative_hash_host_wide_int (DECL_UID (t), val);
5160         }
5161       else
5162         {
5163           gcc_assert (IS_EXPR_CODE_CLASS (class));
5164
5165           val = iterative_hash_object (code, val);
5166
5167           /* Don't hash the type, that can lead to having nodes which
5168              compare equal according to operand_equal_p, but which
5169              have different hash codes.  */
5170           if (code == NOP_EXPR
5171               || code == CONVERT_EXPR
5172               || code == NON_LVALUE_EXPR)
5173             {
5174               /* Make sure to include signness in the hash computation.  */
5175               val += TYPE_UNSIGNED (TREE_TYPE (t));
5176               val = iterative_hash_expr (TREE_OPERAND (t, 0), val);
5177             }
5178
5179           else if (commutative_tree_code (code))
5180             {
5181               /* It's a commutative expression.  We want to hash it the same
5182                  however it appears.  We do this by first hashing both operands
5183                  and then rehashing based on the order of their independent
5184                  hashes.  */
5185               hashval_t one = iterative_hash_expr (TREE_OPERAND (t, 0), 0);
5186               hashval_t two = iterative_hash_expr (TREE_OPERAND (t, 1), 0);
5187               hashval_t t;
5188
5189               if (one > two)
5190                 t = one, one = two, two = t;
5191
5192               val = iterative_hash_hashval_t (one, val);
5193               val = iterative_hash_hashval_t (two, val);
5194             }
5195           else
5196             for (i = TREE_CODE_LENGTH (code) - 1; i >= 0; --i)
5197               val = iterative_hash_expr (TREE_OPERAND (t, i), val);
5198         }
5199       return val;
5200       break;
5201     }
5202 }
5203 \f
5204 /* Constructors for pointer, array and function types.
5205    (RECORD_TYPE, UNION_TYPE and ENUMERAL_TYPE nodes are
5206    constructed by language-dependent code, not here.)  */
5207
5208 /* Construct, lay out and return the type of pointers to TO_TYPE with
5209    mode MODE.  If CAN_ALIAS_ALL is TRUE, indicate this type can
5210    reference all of memory. If such a type has already been
5211    constructed, reuse it.  */
5212
5213 tree
5214 build_pointer_type_for_mode (tree to_type, enum machine_mode mode,
5215                              bool can_alias_all)
5216 {
5217   tree t;
5218
5219   if (to_type == error_mark_node)
5220     return error_mark_node;
5221
5222   /* In some cases, languages will have things that aren't a POINTER_TYPE
5223      (such as a RECORD_TYPE for fat pointers in Ada) as TYPE_POINTER_TO.
5224      In that case, return that type without regard to the rest of our
5225      operands.
5226
5227      ??? This is a kludge, but consistent with the way this function has
5228      always operated and there doesn't seem to be a good way to avoid this
5229      at the moment.  */
5230   if (TYPE_POINTER_TO (to_type) != 0
5231       && TREE_CODE (TYPE_POINTER_TO (to_type)) != POINTER_TYPE)
5232     return TYPE_POINTER_TO (to_type);
5233
5234   /* First, if we already have a type for pointers to TO_TYPE and it's
5235      the proper mode, use it.  */
5236   for (t = TYPE_POINTER_TO (to_type); t; t = TYPE_NEXT_PTR_TO (t))
5237     if (TYPE_MODE (t) == mode && TYPE_REF_CAN_ALIAS_ALL (t) == can_alias_all)
5238       return t;
5239
5240   t = make_node (POINTER_TYPE);
5241
5242   TREE_TYPE (t) = to_type;
5243   TYPE_MODE (t) = mode;
5244   TYPE_REF_CAN_ALIAS_ALL (t) = can_alias_all;
5245   TYPE_NEXT_PTR_TO (t) = TYPE_POINTER_TO (to_type);
5246   TYPE_POINTER_TO (to_type) = t;
5247
5248   if (TYPE_STRUCTURAL_EQUALITY_P (to_type))
5249     SET_TYPE_STRUCTURAL_EQUALITY (t);
5250   else if (TYPE_CANONICAL (to_type) != to_type)
5251     TYPE_CANONICAL (t)
5252       = build_pointer_type_for_mode (TYPE_CANONICAL (to_type),
5253                                      mode, can_alias_all);
5254
5255   /* Lay out the type.  This function has many callers that are concerned
5256      with expression-construction, and this simplifies them all.  */
5257   layout_type (t);
5258
5259   return t;
5260 }
5261
5262 /* By default build pointers in ptr_mode.  */
5263
5264 tree
5265 build_pointer_type (tree to_type)
5266 {
5267   return build_pointer_type_for_mode (to_type, ptr_mode, false);
5268 }
5269
5270 /* Same as build_pointer_type_for_mode, but for REFERENCE_TYPE.  */
5271
5272 tree
5273 build_reference_type_for_mode (tree to_type, enum machine_mode mode,
5274                                bool can_alias_all)
5275 {
5276   tree t;
5277
5278   /* In some cases, languages will have things that aren't a REFERENCE_TYPE
5279      (such as a RECORD_TYPE for fat pointers in Ada) as TYPE_REFERENCE_TO.
5280      In that case, return that type without regard to the rest of our
5281      operands.
5282
5283      ??? This is a kludge, but consistent with the way this function has
5284      always operated and there doesn't seem to be a good way to avoid this
5285      at the moment.  */
5286   if (TYPE_REFERENCE_TO (to_type) != 0
5287       && TREE_CODE (TYPE_REFERENCE_TO (to_type)) != REFERENCE_TYPE)
5288     return TYPE_REFERENCE_TO (to_type);
5289
5290   /* First, if we already have a type for pointers to TO_TYPE and it's
5291      the proper mode, use it.  */
5292   for (t = TYPE_REFERENCE_TO (to_type); t; t = TYPE_NEXT_REF_TO (t))
5293     if (TYPE_MODE (t) == mode && TYPE_REF_CAN_ALIAS_ALL (t) == can_alias_all)
5294       return t;
5295
5296   t = make_node (REFERENCE_TYPE);
5297
5298   TREE_TYPE (t) = to_type;
5299   TYPE_MODE (t) = mode;
5300   TYPE_REF_CAN_ALIAS_ALL (t) = can_alias_all;
5301   TYPE_NEXT_REF_TO (t) = TYPE_REFERENCE_TO (to_type);
5302   TYPE_REFERENCE_TO (to_type) = t;
5303
5304   if (TYPE_STRUCTURAL_EQUALITY_P (to_type))
5305     SET_TYPE_STRUCTURAL_EQUALITY (t);
5306   else if (TYPE_CANONICAL (to_type) != to_type)
5307     TYPE_CANONICAL (t)
5308       = build_reference_type_for_mode (TYPE_CANONICAL (to_type),
5309                                        mode, can_alias_all);
5310
5311   layout_type (t);
5312
5313   return t;
5314 }
5315
5316
5317 /* Build the node for the type of references-to-TO_TYPE by default
5318    in ptr_mode.  */
5319
5320 tree
5321 build_reference_type (tree to_type)
5322 {
5323   return build_reference_type_for_mode (to_type, ptr_mode, false);
5324 }
5325
5326 /* Build a type that is compatible with t but has no cv quals anywhere
5327    in its type, thus
5328
5329    const char *const *const *  ->  char ***.  */
5330
5331 tree
5332 build_type_no_quals (tree t)
5333 {
5334   switch (TREE_CODE (t))
5335     {
5336     case POINTER_TYPE:
5337       return build_pointer_type_for_mode (build_type_no_quals (TREE_TYPE (t)),
5338                                           TYPE_MODE (t),
5339                                           TYPE_REF_CAN_ALIAS_ALL (t));
5340     case REFERENCE_TYPE:
5341       return
5342         build_reference_type_for_mode (build_type_no_quals (TREE_TYPE (t)),
5343                                        TYPE_MODE (t),
5344                                        TYPE_REF_CAN_ALIAS_ALL (t));
5345     default:
5346       return TYPE_MAIN_VARIANT (t);
5347     }
5348 }
5349
5350 /* Create a type of integers to be the TYPE_DOMAIN of an ARRAY_TYPE.
5351    MAXVAL should be the maximum value in the domain
5352    (one less than the length of the array).
5353
5354    The maximum value that MAXVAL can have is INT_MAX for a HOST_WIDE_INT.
5355    We don't enforce this limit, that is up to caller (e.g. language front end).
5356    The limit exists because the result is a signed type and we don't handle
5357    sizes that use more than one HOST_WIDE_INT.  */
5358
5359 tree
5360 build_index_type (tree maxval)
5361 {
5362   tree itype = make_node (INTEGER_TYPE);
5363
5364   TREE_TYPE (itype) = sizetype;
5365   TYPE_PRECISION (itype) = TYPE_PRECISION (sizetype);
5366   TYPE_MIN_VALUE (itype) = size_zero_node;
5367   TYPE_MAX_VALUE (itype) = fold_convert (sizetype, maxval);
5368   TYPE_MODE (itype) = TYPE_MODE (sizetype);
5369   TYPE_SIZE (itype) = TYPE_SIZE (sizetype);
5370   TYPE_SIZE_UNIT (itype) = TYPE_SIZE_UNIT (sizetype);
5371   TYPE_ALIGN (itype) = TYPE_ALIGN (sizetype);
5372   TYPE_USER_ALIGN (itype) = TYPE_USER_ALIGN (sizetype);
5373
5374   if (host_integerp (maxval, 1))
5375     return type_hash_canon (tree_low_cst (maxval, 1), itype);
5376   else
5377     {
5378       /* Since we cannot hash this type, we need to compare it using
5379          structural equality checks. */
5380       SET_TYPE_STRUCTURAL_EQUALITY (itype);
5381       return itype;
5382     }
5383 }
5384
5385 /* Builds a signed or unsigned integer type of precision PRECISION.
5386    Used for C bitfields whose precision does not match that of
5387    built-in target types.  */
5388 tree
5389 build_nonstandard_integer_type (unsigned HOST_WIDE_INT precision,
5390                                 int unsignedp)
5391 {
5392   tree itype = make_node (INTEGER_TYPE);
5393
5394   TYPE_PRECISION (itype) = precision;
5395
5396   if (unsignedp)
5397     fixup_unsigned_type (itype);
5398   else
5399     fixup_signed_type (itype);
5400
5401   if (host_integerp (TYPE_MAX_VALUE (itype), 1))
5402     return type_hash_canon (tree_low_cst (TYPE_MAX_VALUE (itype), 1), itype);
5403
5404   return itype;
5405 }
5406
5407 /* Create a range of some discrete type TYPE (an INTEGER_TYPE,
5408    ENUMERAL_TYPE or BOOLEAN_TYPE), with low bound LOWVAL and
5409    high bound HIGHVAL.  If TYPE is NULL, sizetype is used.  */
5410
5411 tree
5412 build_range_type (tree type, tree lowval, tree highval)
5413 {
5414   tree itype = make_node (INTEGER_TYPE);
5415
5416   TREE_TYPE (itype) = type;
5417   if (type == NULL_TREE)
5418     type = sizetype;
5419
5420   TYPE_MIN_VALUE (itype) = fold_convert (type, lowval);
5421   TYPE_MAX_VALUE (itype) = highval ? fold_convert (type, highval) : NULL;
5422
5423   TYPE_PRECISION (itype) = TYPE_PRECISION (type);
5424   TYPE_MODE (itype) = TYPE_MODE (type);
5425   TYPE_SIZE (itype) = TYPE_SIZE (type);
5426   TYPE_SIZE_UNIT (itype) = TYPE_SIZE_UNIT (type);
5427   TYPE_ALIGN (itype) = TYPE_ALIGN (type);
5428   TYPE_USER_ALIGN (itype) = TYPE_USER_ALIGN (type);
5429
5430   if (host_integerp (lowval, 0) && highval != 0 && host_integerp (highval, 0))
5431     return type_hash_canon (tree_low_cst (highval, 0)
5432                             - tree_low_cst (lowval, 0),
5433                             itype);
5434   else
5435     return itype;
5436 }
5437
5438 /* Just like build_index_type, but takes lowval and highval instead
5439    of just highval (maxval).  */
5440
5441 tree
5442 build_index_2_type (tree lowval, tree highval)
5443 {
5444   return build_range_type (sizetype, lowval, highval);
5445 }
5446
5447 /* Construct, lay out and return the type of arrays of elements with ELT_TYPE
5448    and number of elements specified by the range of values of INDEX_TYPE.
5449    If such a type has already been constructed, reuse it.  */
5450
5451 tree
5452 build_array_type (tree elt_type, tree index_type)
5453 {
5454   tree t;
5455   hashval_t hashcode = 0;
5456
5457   if (TREE_CODE (elt_type) == FUNCTION_TYPE)
5458     {
5459       error ("arrays of functions are not meaningful");
5460       elt_type = integer_type_node;
5461     }
5462
5463   t = make_node (ARRAY_TYPE);
5464   TREE_TYPE (t) = elt_type;
5465   TYPE_DOMAIN (t) = index_type;
5466
5467   if (index_type == 0)
5468     {
5469       tree save = t;
5470       hashcode = iterative_hash_object (TYPE_HASH (elt_type), hashcode);
5471       t = type_hash_canon (hashcode, t);
5472       if (save == t)
5473         layout_type (t);
5474
5475       if (TYPE_CANONICAL (t) == t)
5476         {
5477           if (TYPE_STRUCTURAL_EQUALITY_P (elt_type))
5478             SET_TYPE_STRUCTURAL_EQUALITY (t);
5479           else if (TYPE_CANONICAL (elt_type) != elt_type)
5480             TYPE_CANONICAL (t)
5481               = build_array_type (TYPE_CANONICAL (elt_type), index_type);
5482         }
5483
5484       return t;
5485     }
5486
5487   hashcode = iterative_hash_object (TYPE_HASH (elt_type), hashcode);
5488   hashcode = iterative_hash_object (TYPE_HASH (index_type), hashcode);
5489   t = type_hash_canon (hashcode, t);
5490
5491   if (!COMPLETE_TYPE_P (t))
5492     layout_type (t);
5493
5494   if (TYPE_CANONICAL (t) == t)
5495     {
5496       if (TYPE_STRUCTURAL_EQUALITY_P (elt_type)
5497           || TYPE_STRUCTURAL_EQUALITY_P (index_type))
5498         SET_TYPE_STRUCTURAL_EQUALITY (t);
5499       else if (TYPE_CANONICAL (elt_type) != elt_type
5500                || TYPE_CANONICAL (index_type) != index_type)
5501         TYPE_CANONICAL (t)
5502           = build_array_type (TYPE_CANONICAL (elt_type),
5503                               TYPE_CANONICAL (index_type));
5504     }
5505
5506   return t;
5507 }
5508
5509 /* Return the TYPE of the elements comprising
5510    the innermost dimension of ARRAY.  */
5511
5512 tree
5513 get_inner_array_type (tree array)
5514 {
5515   tree type = TREE_TYPE (array);
5516
5517   while (TREE_CODE (type) == ARRAY_TYPE)
5518     type = TREE_TYPE (type);
5519
5520   return type;
5521 }
5522
5523 /* Construct, lay out and return
5524    the type of functions returning type VALUE_TYPE
5525    given arguments of types ARG_TYPES.
5526    ARG_TYPES is a chain of TREE_LIST nodes whose TREE_VALUEs
5527    are data type nodes for the arguments of the function.
5528    If such a type has already been constructed, reuse it.  */
5529
5530 tree
5531 build_function_type (tree value_type, tree arg_types)
5532 {
5533   tree t;
5534   hashval_t hashcode = 0;
5535
5536   if (TREE_CODE (value_type) == FUNCTION_TYPE)
5537     {
5538       error ("function return type cannot be function");
5539       value_type = integer_type_node;
5540     }
5541
5542   /* Make a node of the sort we want.  */
5543   t = make_node (FUNCTION_TYPE);
5544   TREE_TYPE (t) = value_type;
5545   TYPE_ARG_TYPES (t) = arg_types;
5546
5547   /* We don't have canonicalization of function types, yet. */
5548   SET_TYPE_STRUCTURAL_EQUALITY (t);
5549
5550   /* If we already have such a type, use the old one.  */
5551   hashcode = iterative_hash_object (TYPE_HASH (value_type), hashcode);
5552   hashcode = type_hash_list (arg_types, hashcode);
5553   t = type_hash_canon (hashcode, t);
5554
5555   if (!COMPLETE_TYPE_P (t))
5556     layout_type (t);
5557   return t;
5558 }
5559
5560 /* Build a function type.  The RETURN_TYPE is the type returned by the
5561    function.  If additional arguments are provided, they are
5562    additional argument types.  The list of argument types must always
5563    be terminated by NULL_TREE.  */
5564
5565 tree
5566 build_function_type_list (tree return_type, ...)
5567 {
5568   tree t, args, last;
5569   va_list p;
5570
5571   va_start (p, return_type);
5572
5573   t = va_arg (p, tree);
5574   for (args = NULL_TREE; t != NULL_TREE; t = va_arg (p, tree))
5575     args = tree_cons (NULL_TREE, t, args);
5576
5577   if (args == NULL_TREE)
5578     args = void_list_node;
5579   else
5580     {
5581       last = args;
5582       args = nreverse (args);
5583       TREE_CHAIN (last) = void_list_node;
5584     }
5585   args = build_function_type (return_type, args);
5586
5587   va_end (p);
5588   return args;
5589 }
5590
5591 /* Build a METHOD_TYPE for a member of BASETYPE.  The RETTYPE (a TYPE)
5592    and ARGTYPES (a TREE_LIST) are the return type and arguments types
5593    for the method.  An implicit additional parameter (of type
5594    pointer-to-BASETYPE) is added to the ARGTYPES.  */
5595
5596 tree
5597 build_method_type_directly (tree basetype,
5598                             tree rettype,
5599                             tree argtypes)
5600 {
5601   tree t;
5602   tree ptype;
5603   int hashcode = 0;
5604
5605   /* Make a node of the sort we want.  */
5606   t = make_node (METHOD_TYPE);
5607
5608   TYPE_METHOD_BASETYPE (t) = TYPE_MAIN_VARIANT (basetype);
5609   TREE_TYPE (t) = rettype;
5610   ptype = build_pointer_type (basetype);
5611
5612   /* The actual arglist for this function includes a "hidden" argument
5613      which is "this".  Put it into the list of argument types.  */
5614   argtypes = tree_cons (NULL_TREE, ptype, argtypes);
5615   TYPE_ARG_TYPES (t) = argtypes;
5616
5617   /* We don't have canonicalization of method types yet. */
5618   SET_TYPE_STRUCTURAL_EQUALITY (t);
5619
5620   /* If we already have such a type, use the old one.  */
5621   hashcode = iterative_hash_object (TYPE_HASH (basetype), hashcode);
5622   hashcode = iterative_hash_object (TYPE_HASH (rettype), hashcode);
5623   hashcode = type_hash_list (argtypes, hashcode);
5624   t = type_hash_canon (hashcode, t);
5625
5626   if (!COMPLETE_TYPE_P (t))
5627     layout_type (t);
5628
5629   return t;
5630 }
5631
5632 /* Construct, lay out and return the type of methods belonging to class
5633    BASETYPE and whose arguments and values are described by TYPE.
5634    If that type exists already, reuse it.
5635    TYPE must be a FUNCTION_TYPE node.  */
5636
5637 tree
5638 build_method_type (tree basetype, tree type)
5639 {
5640   gcc_assert (TREE_CODE (type) == FUNCTION_TYPE);
5641
5642   return build_method_type_directly (basetype,
5643                                      TREE_TYPE (type),
5644                                      TYPE_ARG_TYPES (type));
5645 }
5646
5647 /* Construct, lay out and return the type of offsets to a value
5648    of type TYPE, within an object of type BASETYPE.
5649    If a suitable offset type exists already, reuse it.  */
5650
5651 tree
5652 build_offset_type (tree basetype, tree type)
5653 {
5654   tree t;
5655   hashval_t hashcode = 0;
5656
5657   /* Make a node of the sort we want.  */
5658   t = make_node (OFFSET_TYPE);
5659
5660   TYPE_OFFSET_BASETYPE (t) = TYPE_MAIN_VARIANT (basetype);
5661   TREE_TYPE (t) = type;
5662
5663   /* If we already have such a type, use the old one.  */
5664   hashcode = iterative_hash_object (TYPE_HASH (basetype), hashcode);
5665   hashcode = iterative_hash_object (TYPE_HASH (type), hashcode);
5666   t = type_hash_canon (hashcode, t);
5667
5668   if (!COMPLETE_TYPE_P (t))
5669     layout_type (t);
5670
5671   if (TYPE_CANONICAL (t) == t)
5672     {
5673       if (TYPE_STRUCTURAL_EQUALITY_P (basetype)
5674           || TYPE_STRUCTURAL_EQUALITY_P (type))
5675         SET_TYPE_STRUCTURAL_EQUALITY (t);
5676       else if (TYPE_CANONICAL (basetype) != basetype
5677                || TYPE_CANONICAL (type) != type)
5678         TYPE_CANONICAL (t)
5679           = build_offset_type (TYPE_CANONICAL (basetype),
5680                                TYPE_CANONICAL (type));
5681     }
5682
5683   return t;
5684 }
5685
5686 /* Create a complex type whose components are COMPONENT_TYPE.  */
5687
5688 tree
5689 build_complex_type (tree component_type)
5690 {
5691   tree t;
5692   hashval_t hashcode;
5693
5694   /* Make a node of the sort we want.  */
5695   t = make_node (COMPLEX_TYPE);
5696
5697   TREE_TYPE (t) = TYPE_MAIN_VARIANT (component_type);
5698
5699   /* If we already have such a type, use the old one.  */
5700   hashcode = iterative_hash_object (TYPE_HASH (component_type), 0);
5701   t = type_hash_canon (hashcode, t);
5702
5703   if (!COMPLETE_TYPE_P (t))
5704     layout_type (t);
5705
5706   if (TYPE_CANONICAL (t) == t)
5707     {
5708       if (TYPE_STRUCTURAL_EQUALITY_P (component_type))
5709         SET_TYPE_STRUCTURAL_EQUALITY (t);
5710       else if (TYPE_CANONICAL (component_type) != component_type)
5711         TYPE_CANONICAL (t)
5712           = build_complex_type (TYPE_CANONICAL (component_type));
5713     }
5714
5715   /* If we are writing Dwarf2 output we need to create a name,
5716      since complex is a fundamental type.  */
5717   if ((write_symbols == DWARF2_DEBUG || write_symbols == VMS_AND_DWARF2_DEBUG)
5718       && ! TYPE_NAME (t))
5719     {
5720       const char *name;
5721       if (component_type == char_type_node)
5722         name = "complex char";
5723       else if (component_type == signed_char_type_node)
5724         name = "complex signed char";
5725       else if (component_type == unsigned_char_type_node)
5726         name = "complex unsigned char";
5727       else if (component_type == short_integer_type_node)
5728         name = "complex short int";
5729       else if (component_type == short_unsigned_type_node)
5730         name = "complex short unsigned int";
5731       else if (component_type == integer_type_node)
5732         name = "complex int";
5733       else if (component_type == unsigned_type_node)
5734         name = "complex unsigned int";
5735       else if (component_type == long_integer_type_node)
5736         name = "complex long int";
5737       else if (component_type == long_unsigned_type_node)
5738         name = "complex long unsigned int";
5739       else if (component_type == long_long_integer_type_node)
5740         name = "complex long long int";
5741       else if (component_type == long_long_unsigned_type_node)
5742         name = "complex long long unsigned int";
5743       else
5744         name = 0;
5745
5746       if (name != 0)
5747         TYPE_NAME (t) = get_identifier (name);
5748     }
5749
5750   return build_qualified_type (t, TYPE_QUALS (component_type));
5751 }
5752 \f
5753 /* Return OP, stripped of any conversions to wider types as much as is safe.
5754    Converting the value back to OP's type makes a value equivalent to OP.
5755
5756    If FOR_TYPE is nonzero, we return a value which, if converted to
5757    type FOR_TYPE, would be equivalent to converting OP to type FOR_TYPE.
5758
5759    If FOR_TYPE is nonzero, unaligned bit-field references may be changed to the
5760    narrowest type that can hold the value, even if they don't exactly fit.
5761    Otherwise, bit-field references are changed to a narrower type
5762    only if they can be fetched directly from memory in that type.
5763
5764    OP must have integer, real or enumeral type.  Pointers are not allowed!
5765
5766    There are some cases where the obvious value we could return
5767    would regenerate to OP if converted to OP's type,
5768    but would not extend like OP to wider types.
5769    If FOR_TYPE indicates such extension is contemplated, we eschew such values.
5770    For example, if OP is (unsigned short)(signed char)-1,
5771    we avoid returning (signed char)-1 if FOR_TYPE is int,
5772    even though extending that to an unsigned short would regenerate OP,
5773    since the result of extending (signed char)-1 to (int)
5774    is different from (int) OP.  */
5775
5776 tree
5777 get_unwidened (tree op, tree for_type)
5778 {
5779   /* Set UNS initially if converting OP to FOR_TYPE is a zero-extension.  */
5780   tree type = TREE_TYPE (op);
5781   unsigned final_prec
5782     = TYPE_PRECISION (for_type != 0 ? for_type : type);
5783   int uns
5784     = (for_type != 0 && for_type != type
5785        && final_prec > TYPE_PRECISION (type)
5786        && TYPE_UNSIGNED (type));
5787   tree win = op;
5788
5789   while (TREE_CODE (op) == NOP_EXPR
5790          || TREE_CODE (op) == CONVERT_EXPR)
5791     {
5792       int bitschange;
5793
5794       /* TYPE_PRECISION on vector types has different meaning
5795          (TYPE_VECTOR_SUBPARTS) and casts from vectors are view conversions,
5796          so avoid them here.  */
5797       if (TREE_CODE (TREE_TYPE (TREE_OPERAND (op, 0))) == VECTOR_TYPE)
5798         break;
5799
5800       bitschange = TYPE_PRECISION (TREE_TYPE (op))
5801                    - TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op, 0)));
5802
5803       /* Truncations are many-one so cannot be removed.
5804          Unless we are later going to truncate down even farther.  */
5805       if (bitschange < 0
5806           && final_prec > TYPE_PRECISION (TREE_TYPE (op)))
5807         break;
5808
5809       /* See what's inside this conversion.  If we decide to strip it,
5810          we will set WIN.  */
5811       op = TREE_OPERAND (op, 0);
5812
5813       /* If we have not stripped any zero-extensions (uns is 0),
5814          we can strip any kind of extension.
5815          If we have previously stripped a zero-extension,
5816          only zero-extensions can safely be stripped.
5817          Any extension can be stripped if the bits it would produce
5818          are all going to be discarded later by truncating to FOR_TYPE.  */
5819
5820       if (bitschange > 0)
5821         {
5822           if (! uns || final_prec <= TYPE_PRECISION (TREE_TYPE (op)))
5823             win = op;
5824           /* TYPE_UNSIGNED says whether this is a zero-extension.
5825              Let's avoid computing it if it does not affect WIN
5826              and if UNS will not be needed again.  */
5827           if ((uns
5828                || TREE_CODE (op) == NOP_EXPR
5829                || TREE_CODE (op) == CONVERT_EXPR)
5830               && TYPE_UNSIGNED (TREE_TYPE (op)))
5831             {
5832               uns = 1;
5833               win = op;
5834             }
5835         }
5836     }
5837
5838   if (TREE_CODE (op) == COMPONENT_REF
5839       /* Since type_for_size always gives an integer type.  */
5840       && TREE_CODE (type) != REAL_TYPE
5841       /* Don't crash if field not laid out yet.  */
5842       && DECL_SIZE (TREE_OPERAND (op, 1)) != 0
5843       && host_integerp (DECL_SIZE (TREE_OPERAND (op, 1)), 1))
5844     {
5845       unsigned int innerprec
5846         = tree_low_cst (DECL_SIZE (TREE_OPERAND (op, 1)), 1);
5847       int unsignedp = (DECL_UNSIGNED (TREE_OPERAND (op, 1))
5848                        || TYPE_UNSIGNED (TREE_TYPE (TREE_OPERAND (op, 1))));
5849       type = lang_hooks.types.type_for_size (innerprec, unsignedp);
5850
5851       /* We can get this structure field in the narrowest type it fits in.
5852          If FOR_TYPE is 0, do this only for a field that matches the
5853          narrower type exactly and is aligned for it
5854          The resulting extension to its nominal type (a fullword type)
5855          must fit the same conditions as for other extensions.  */
5856
5857       if (type != 0
5858           && INT_CST_LT_UNSIGNED (TYPE_SIZE (type), TYPE_SIZE (TREE_TYPE (op)))
5859           && (for_type || ! DECL_BIT_FIELD (TREE_OPERAND (op, 1)))
5860           && (! uns || final_prec <= innerprec || unsignedp))
5861         {
5862           win = build3 (COMPONENT_REF, type, TREE_OPERAND (op, 0),
5863                         TREE_OPERAND (op, 1), NULL_TREE);
5864           TREE_SIDE_EFFECTS (win) = TREE_SIDE_EFFECTS (op);
5865           TREE_THIS_VOLATILE (win) = TREE_THIS_VOLATILE (op);
5866         }
5867     }
5868
5869   return win;
5870 }
5871 \f
5872 /* Return OP or a simpler expression for a narrower value
5873    which can be sign-extended or zero-extended to give back OP.
5874    Store in *UNSIGNEDP_PTR either 1 if the value should be zero-extended
5875    or 0 if the value should be sign-extended.  */
5876
5877 tree
5878 get_narrower (tree op, int *unsignedp_ptr)
5879 {
5880   int uns = 0;
5881   int first = 1;
5882   tree win = op;
5883   bool integral_p = INTEGRAL_TYPE_P (TREE_TYPE (op));
5884
5885   while (TREE_CODE (op) == NOP_EXPR)
5886     {
5887       int bitschange
5888         = (TYPE_PRECISION (TREE_TYPE (op))
5889            - TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (op, 0))));
5890
5891       /* Truncations are many-one so cannot be removed.  */
5892       if (bitschange < 0)
5893         break;
5894
5895       /* See what's inside this conversion.  If we decide to strip it,
5896          we will set WIN.  */
5897
5898       if (bitschange > 0)
5899         {
5900           op = TREE_OPERAND (op, 0);
5901           /* An extension: the outermost one can be stripped,
5902              but remember whether it is zero or sign extension.  */
5903           if (first)
5904             uns = TYPE_UNSIGNED (TREE_TYPE (op));
5905           /* Otherwise, if a sign extension has been stripped,
5906              only sign extensions can now be stripped;
5907              if a zero extension has been stripped, only zero-extensions.  */
5908           else if (uns != TYPE_UNSIGNED (TREE_TYPE (op)))
5909             break;
5910           first = 0;
5911         }
5912       else /* bitschange == 0 */
5913         {
5914           /* A change in nominal type can always be stripped, but we must
5915              preserve the unsignedness.  */
5916           if (first)
5917             uns = TYPE_UNSIGNED (TREE_TYPE (op));
5918           first = 0;
5919           op = TREE_OPERAND (op, 0);
5920           /* Keep trying to narrow, but don't assign op to win if it
5921              would turn an integral type into something else.  */
5922           if (INTEGRAL_TYPE_P (TREE_TYPE (op)) != integral_p)
5923             continue;
5924         }
5925
5926       win = op;
5927     }
5928
5929   if (TREE_CODE (op) == COMPONENT_REF
5930       /* Since type_for_size always gives an integer type.  */
5931       && TREE_CODE (TREE_TYPE (op)) != REAL_TYPE
5932       /* Ensure field is laid out already.  */
5933       && DECL_SIZE (TREE_OPERAND (op, 1)) != 0
5934       && host_integerp (DECL_SIZE (TREE_OPERAND (op, 1)), 1))
5935     {
5936       unsigned HOST_WIDE_INT innerprec
5937         = tree_low_cst (DECL_SIZE (TREE_OPERAND (op, 1)), 1);
5938       int unsignedp = (DECL_UNSIGNED (TREE_OPERAND (op, 1))
5939                        || TYPE_UNSIGNED (TREE_TYPE (TREE_OPERAND (op, 1))));
5940       tree type = lang_hooks.types.type_for_size (innerprec, unsignedp);
5941
5942       /* We can get this structure field in a narrower type that fits it,
5943          but the resulting extension to its nominal type (a fullword type)
5944          must satisfy the same conditions as for other extensions.
5945
5946          Do this only for fields that are aligned (not bit-fields),
5947          because when bit-field insns will be used there is no
5948          advantage in doing this.  */
5949
5950       if (innerprec < TYPE_PRECISION (TREE_TYPE (op))
5951           && ! DECL_BIT_FIELD (TREE_OPERAND (op, 1))
5952           && (first || uns == DECL_UNSIGNED (TREE_OPERAND (op, 1)))
5953           && type != 0)
5954         {
5955           if (first)
5956             uns = DECL_UNSIGNED (TREE_OPERAND (op, 1));
5957           win = fold_convert (type, op);
5958         }
5959     }
5960
5961   *unsignedp_ptr = uns;
5962   return win;
5963 }
5964 \f
5965 /* Nonzero if integer constant C has a value that is permissible
5966    for type TYPE (an INTEGER_TYPE).  */
5967
5968 int
5969 int_fits_type_p (tree c, tree type)
5970 {
5971   tree type_low_bound = TYPE_MIN_VALUE (type);
5972   tree type_high_bound = TYPE_MAX_VALUE (type);
5973   bool ok_for_low_bound, ok_for_high_bound;
5974   unsigned HOST_WIDE_INT low;
5975   HOST_WIDE_INT high;
5976
5977   /* If at least one bound of the type is a constant integer, we can check
5978      ourselves and maybe make a decision. If no such decision is possible, but
5979      this type is a subtype, try checking against that.  Otherwise, use
5980      fit_double_type, which checks against the precision.
5981
5982      Compute the status for each possibly constant bound, and return if we see
5983      one does not match. Use ok_for_xxx_bound for this purpose, assigning -1
5984      for "unknown if constant fits", 0 for "constant known *not* to fit" and 1
5985      for "constant known to fit".  */
5986
5987   /* Check if C >= type_low_bound.  */
5988   if (type_low_bound && TREE_CODE (type_low_bound) == INTEGER_CST)
5989     {
5990       if (tree_int_cst_lt (c, type_low_bound))
5991         return 0;
5992       ok_for_low_bound = true;
5993     }
5994   else
5995     ok_for_low_bound = false;
5996
5997   /* Check if c <= type_high_bound.  */
5998   if (type_high_bound && TREE_CODE (type_high_bound) == INTEGER_CST)
5999     {
6000       if (tree_int_cst_lt (type_high_bound, c))
6001         return 0;
6002       ok_for_high_bound = true;
6003     }
6004   else
6005     ok_for_high_bound = false;
6006
6007   /* If the constant fits both bounds, the result is known.  */
6008   if (ok_for_low_bound && ok_for_high_bound)
6009     return 1;
6010
6011   /* Perform some generic filtering which may allow making a decision
6012      even if the bounds are not constant.  First, negative integers
6013      never fit in unsigned types, */
6014   if (TYPE_UNSIGNED (type) && tree_int_cst_sgn (c) < 0)
6015     return 0;
6016
6017   /* Second, narrower types always fit in wider ones.  */
6018   if (TYPE_PRECISION (type) > TYPE_PRECISION (TREE_TYPE (c)))
6019     return 1;
6020
6021   /* Third, unsigned integers with top bit set never fit signed types.  */
6022   if (! TYPE_UNSIGNED (type)
6023       && TYPE_UNSIGNED (TREE_TYPE (c))
6024       && tree_int_cst_msb (c))
6025     return 0;
6026
6027   /* If we haven't been able to decide at this point, there nothing more we
6028      can check ourselves here.  Look at the base type if we have one and it
6029      has the same precision.  */
6030   if (TREE_CODE (type) == INTEGER_TYPE
6031       && TREE_TYPE (type) != 0
6032       && TYPE_PRECISION (type) == TYPE_PRECISION (TREE_TYPE (type)))
6033     return int_fits_type_p (c, TREE_TYPE (type));
6034
6035   /* Or to fit_double_type, if nothing else.  */
6036   low = TREE_INT_CST_LOW (c);
6037   high = TREE_INT_CST_HIGH (c);
6038   return !fit_double_type (low, high, &low, &high, type);
6039 }
6040
6041 /* Subprogram of following function.  Called by walk_tree.
6042
6043    Return *TP if it is an automatic variable or parameter of the
6044    function passed in as DATA.  */
6045
6046 static tree
6047 find_var_from_fn (tree *tp, int *walk_subtrees, void *data)
6048 {
6049   tree fn = (tree) data;
6050
6051   if (TYPE_P (*tp))
6052     *walk_subtrees = 0;
6053
6054   else if (DECL_P (*tp)
6055            && lang_hooks.tree_inlining.auto_var_in_fn_p (*tp, fn))
6056     return *tp;
6057
6058   return NULL_TREE;
6059 }
6060
6061 /* Returns true if T is, contains, or refers to a type with variable
6062    size.  For METHOD_TYPEs and FUNCTION_TYPEs we exclude the
6063    arguments, but not the return type.  If FN is nonzero, only return
6064    true if a modifier of the type or position of FN is a variable or
6065    parameter inside FN.
6066
6067    This concept is more general than that of C99 'variably modified types':
6068    in C99, a struct type is never variably modified because a VLA may not
6069    appear as a structure member.  However, in GNU C code like:
6070
6071      struct S { int i[f()]; };
6072
6073    is valid, and other languages may define similar constructs.  */
6074
6075 bool
6076 variably_modified_type_p (tree type, tree fn)
6077 {
6078   tree t;
6079
6080 /* Test if T is either variable (if FN is zero) or an expression containing
6081    a variable in FN.  */
6082 #define RETURN_TRUE_IF_VAR(T)                                           \
6083   do { tree _t = (T);                                                   \
6084     if (_t && _t != error_mark_node && TREE_CODE (_t) != INTEGER_CST    \
6085         && (!fn || walk_tree (&_t, find_var_from_fn, fn, NULL)))        \
6086       return true;  } while (0)
6087
6088   if (type == error_mark_node)
6089     return false;
6090
6091   /* If TYPE itself has variable size, it is variably modified.  */
6092   RETURN_TRUE_IF_VAR (TYPE_SIZE (type));
6093   RETURN_TRUE_IF_VAR (TYPE_SIZE_UNIT (type));
6094
6095   switch (TREE_CODE (type))
6096     {
6097     case POINTER_TYPE:
6098     case REFERENCE_TYPE:
6099     case VECTOR_TYPE:
6100       if (variably_modified_type_p (TREE_TYPE (type), fn))
6101         return true;
6102       break;
6103
6104     case FUNCTION_TYPE:
6105     case METHOD_TYPE:
6106       /* If TYPE is a function type, it is variably modified if the
6107          return type is variably modified.  */
6108       if (variably_modified_type_p (TREE_TYPE (type), fn))
6109           return true;
6110       break;
6111
6112     case INTEGER_TYPE:
6113     case REAL_TYPE:
6114     case ENUMERAL_TYPE:
6115     case BOOLEAN_TYPE:
6116       /* Scalar types are variably modified if their end points
6117          aren't constant.  */
6118       RETURN_TRUE_IF_VAR (TYPE_MIN_VALUE (type));
6119       RETURN_TRUE_IF_VAR (TYPE_MAX_VALUE (type));
6120       break;
6121
6122     case RECORD_TYPE:
6123     case UNION_TYPE:
6124     case QUAL_UNION_TYPE:
6125       /* We can't see if any of the fields are variably-modified by the
6126          definition we normally use, since that would produce infinite
6127          recursion via pointers.  */
6128       /* This is variably modified if some field's type is.  */
6129       for (t = TYPE_FIELDS (type); t; t = TREE_CHAIN (t))
6130         if (TREE_CODE (t) == FIELD_DECL)
6131           {
6132             RETURN_TRUE_IF_VAR (DECL_FIELD_OFFSET (t));
6133             RETURN_TRUE_IF_VAR (DECL_SIZE (t));
6134             RETURN_TRUE_IF_VAR (DECL_SIZE_UNIT (t));
6135
6136             if (TREE_CODE (type) == QUAL_UNION_TYPE)
6137               RETURN_TRUE_IF_VAR (DECL_QUALIFIER (t));
6138           }
6139         break;
6140
6141     case ARRAY_TYPE:
6142       /* Do not call ourselves to avoid infinite recursion.  This is
6143          variably modified if the element type is.  */
6144       RETURN_TRUE_IF_VAR (TYPE_SIZE (TREE_TYPE (type)));
6145       RETURN_TRUE_IF_VAR (TYPE_SIZE_UNIT (TREE_TYPE (type)));
6146       break;
6147
6148     default:
6149       break;
6150     }
6151
6152   /* The current language may have other cases to check, but in general,
6153      all other types are not variably modified.  */
6154   return lang_hooks.tree_inlining.var_mod_type_p (type, fn);
6155
6156 #undef RETURN_TRUE_IF_VAR
6157 }
6158
6159 /* Given a DECL or TYPE, return the scope in which it was declared, or
6160    NULL_TREE if there is no containing scope.  */
6161
6162 tree
6163 get_containing_scope (tree t)
6164 {
6165   return (TYPE_P (t) ? TYPE_CONTEXT (t) : DECL_CONTEXT (t));
6166 }
6167
6168 /* Return the innermost context enclosing DECL that is
6169    a FUNCTION_DECL, or zero if none.  */
6170
6171 tree
6172 decl_function_context (tree decl)
6173 {
6174   tree context;
6175
6176   if (TREE_CODE (decl) == ERROR_MARK)
6177     return 0;
6178
6179   /* C++ virtual functions use DECL_CONTEXT for the class of the vtable
6180      where we look up the function at runtime.  Such functions always take
6181      a first argument of type 'pointer to real context'.
6182
6183      C++ should really be fixed to use DECL_CONTEXT for the real context,
6184      and use something else for the "virtual context".  */
6185   else if (TREE_CODE (decl) == FUNCTION_DECL && DECL_VINDEX (decl))
6186     context
6187       = TYPE_MAIN_VARIANT
6188         (TREE_TYPE (TREE_VALUE (TYPE_ARG_TYPES (TREE_TYPE (decl)))));
6189   else
6190     context = DECL_CONTEXT (decl);
6191
6192   while (context && TREE_CODE (context) != FUNCTION_DECL)
6193     {
6194       if (TREE_CODE (context) == BLOCK)
6195         context = BLOCK_SUPERCONTEXT (context);
6196       else
6197         context = get_containing_scope (context);
6198     }
6199
6200   return context;
6201 }
6202
6203 /* Return the innermost context enclosing DECL that is
6204    a RECORD_TYPE, UNION_TYPE or QUAL_UNION_TYPE, or zero if none.
6205    TYPE_DECLs and FUNCTION_DECLs are transparent to this function.  */
6206
6207 tree
6208 decl_type_context (tree decl)
6209 {
6210   tree context = DECL_CONTEXT (decl);
6211
6212   while (context)
6213     switch (TREE_CODE (context))
6214       {
6215       case NAMESPACE_DECL:
6216       case TRANSLATION_UNIT_DECL:
6217         return NULL_TREE;
6218
6219       case RECORD_TYPE:
6220       case UNION_TYPE:
6221       case QUAL_UNION_TYPE:
6222         return context;
6223
6224       case TYPE_DECL:
6225       case FUNCTION_DECL:
6226         context = DECL_CONTEXT (context);
6227         break;
6228
6229       case BLOCK:
6230         context = BLOCK_SUPERCONTEXT (context);
6231         break;
6232
6233       default:
6234         gcc_unreachable ();
6235       }
6236
6237   return NULL_TREE;
6238 }
6239
6240 /* CALL is a CALL_EXPR.  Return the declaration for the function
6241    called, or NULL_TREE if the called function cannot be
6242    determined.  */
6243
6244 tree
6245 get_callee_fndecl (tree call)
6246 {
6247   tree addr;
6248
6249   if (call == error_mark_node)
6250     return call;
6251
6252   /* It's invalid to call this function with anything but a
6253      CALL_EXPR.  */
6254   gcc_assert (TREE_CODE (call) == CALL_EXPR);
6255
6256   /* The first operand to the CALL is the address of the function
6257      called.  */
6258   addr = TREE_OPERAND (call, 0);
6259
6260   STRIP_NOPS (addr);
6261
6262   /* If this is a readonly function pointer, extract its initial value.  */
6263   if (DECL_P (addr) && TREE_CODE (addr) != FUNCTION_DECL
6264       && TREE_READONLY (addr) && ! TREE_THIS_VOLATILE (addr)
6265       && DECL_INITIAL (addr))
6266     addr = DECL_INITIAL (addr);
6267
6268   /* If the address is just `&f' for some function `f', then we know
6269      that `f' is being called.  */
6270   if (TREE_CODE (addr) == ADDR_EXPR
6271       && TREE_CODE (TREE_OPERAND (addr, 0)) == FUNCTION_DECL)
6272     return TREE_OPERAND (addr, 0);
6273
6274   /* We couldn't figure out what was being called.  Maybe the front
6275      end has some idea.  */
6276   return lang_hooks.lang_get_callee_fndecl (call);
6277 }
6278
6279 /* Print debugging information about tree nodes generated during the compile,
6280    and any language-specific information.  */
6281
6282 void
6283 dump_tree_statistics (void)
6284 {
6285 #ifdef GATHER_STATISTICS
6286   int i;
6287   int total_nodes, total_bytes;
6288 #endif
6289
6290   fprintf (stderr, "\n??? tree nodes created\n\n");
6291 #ifdef GATHER_STATISTICS
6292   fprintf (stderr, "Kind                   Nodes      Bytes\n");
6293   fprintf (stderr, "---------------------------------------\n");
6294   total_nodes = total_bytes = 0;
6295   for (i = 0; i < (int) all_kinds; i++)
6296     {
6297       fprintf (stderr, "%-20s %7d %10d\n", tree_node_kind_names[i],
6298                tree_node_counts[i], tree_node_sizes[i]);
6299       total_nodes += tree_node_counts[i];
6300       total_bytes += tree_node_sizes[i];
6301     }
6302   fprintf (stderr, "---------------------------------------\n");
6303   fprintf (stderr, "%-20s %7d %10d\n", "Total", total_nodes, total_bytes);
6304   fprintf (stderr, "---------------------------------------\n");
6305   ssanames_print_statistics ();
6306   phinodes_print_statistics ();
6307 #else
6308   fprintf (stderr, "(No per-node statistics)\n");
6309 #endif
6310   print_type_hash_statistics ();
6311   print_debug_expr_statistics ();
6312   print_value_expr_statistics ();
6313   print_restrict_base_statistics ();
6314   lang_hooks.print_statistics ();
6315 }
6316 \f
6317 #define FILE_FUNCTION_FORMAT "_GLOBAL__%s_%s"
6318
6319 /* Generate a crc32 of a string.  */
6320
6321 unsigned
6322 crc32_string (unsigned chksum, const char *string)
6323 {
6324   do
6325     {
6326       unsigned value = *string << 24;
6327       unsigned ix;
6328
6329       for (ix = 8; ix--; value <<= 1)
6330         {
6331           unsigned feedback;
6332
6333           feedback = (value ^ chksum) & 0x80000000 ? 0x04c11db7 : 0;
6334           chksum <<= 1;
6335           chksum ^= feedback;
6336         }
6337     }
6338   while (*string++);
6339   return chksum;
6340 }
6341
6342 /* P is a string that will be used in a symbol.  Mask out any characters
6343    that are not valid in that context.  */
6344
6345 void
6346 clean_symbol_name (char *p)
6347 {
6348   for (; *p; p++)
6349     if (! (ISALNUM (*p)
6350 #ifndef NO_DOLLAR_IN_LABEL      /* this for `$'; unlikely, but... -- kr */
6351             || *p == '$'
6352 #endif
6353 #ifndef NO_DOT_IN_LABEL         /* this for `.'; unlikely, but...  */
6354             || *p == '.'
6355 #endif
6356            ))
6357       *p = '_';
6358 }
6359
6360 /* Generate a name for a special-purpose function function.
6361    The generated name may need to be unique across the whole link.
6362    TYPE is some string to identify the purpose of this function to the
6363    linker or collect2; it must start with an uppercase letter,
6364    one of:
6365    I - for constructors
6366    D - for destructors
6367    N - for C++ anonymous namespaces
6368    F - for DWARF unwind frame information.  */
6369
6370 tree
6371 get_file_function_name (const char *type)
6372 {
6373   char *buf;
6374   const char *p;
6375   char *q;
6376
6377   /* If we already have a name we know to be unique, just use that.  */
6378   if (first_global_object_name)
6379     p = first_global_object_name;
6380   /* If the target is handling the constructors/destructors, they
6381      will be local to this file and the name is only necessary for
6382      debugging purposes.  */
6383   else if ((type[0] == 'I' || type[0] == 'D') && targetm.have_ctors_dtors)
6384     {
6385       const char *file = main_input_filename;
6386       if (! file)
6387         file = input_filename;
6388       /* Just use the file's basename, because the full pathname
6389          might be quite long.  */
6390       p = strrchr (file, '/');
6391       if (p)
6392         p++;
6393       else
6394         p = file;
6395       p = q = ASTRDUP (p);
6396       clean_symbol_name (q);
6397     }
6398   else
6399     {
6400       /* Otherwise, the name must be unique across the entire link.
6401          We don't have anything that we know to be unique to this translation
6402          unit, so use what we do have and throw in some randomness.  */
6403       unsigned len;
6404       const char *name = weak_global_object_name;
6405       const char *file = main_input_filename;
6406
6407       if (! name)
6408         name = "";
6409       if (! file)
6410         file = input_filename;
6411
6412       len = strlen (file);
6413       q = alloca (9 * 2 + len + 1);
6414       memcpy (q, file, len + 1);
6415       clean_symbol_name (q);
6416
6417       sprintf (q + len, "_%08X_%08X", crc32_string (0, name),
6418                crc32_string (0, flag_random_seed));
6419
6420       p = q;
6421     }
6422
6423   buf = alloca (sizeof (FILE_FUNCTION_FORMAT) + strlen (p) + strlen (type));
6424
6425   /* Set up the name of the file-level functions we may need.
6426      Use a global object (which is already required to be unique over
6427      the program) rather than the file name (which imposes extra
6428      constraints).  */
6429   sprintf (buf, FILE_FUNCTION_FORMAT, type, p);
6430
6431   return get_identifier (buf);
6432 }
6433 \f
6434 #if defined ENABLE_TREE_CHECKING && (GCC_VERSION >= 2007)
6435
6436 /* Complain that the tree code of NODE does not match the expected 0
6437    terminated list of trailing codes. The trailing code list can be
6438    empty, for a more vague error message.  FILE, LINE, and FUNCTION
6439    are of the caller.  */
6440
6441 void
6442 tree_check_failed (const tree node, const char *file,
6443                    int line, const char *function, ...)
6444 {
6445   va_list args;
6446   char *buffer;
6447   unsigned length = 0;
6448   int code;
6449
6450   va_start (args, function);
6451   while ((code = va_arg (args, int)))
6452     length += 4 + strlen (tree_code_name[code]);
6453   va_end (args);
6454   if (length)
6455     {
6456       va_start (args, function);
6457       length += strlen ("expected ");
6458       buffer = alloca (length);
6459       length = 0;
6460       while ((code = va_arg (args, int)))
6461         {
6462           const char *prefix = length ? " or " : "expected ";
6463
6464           strcpy (buffer + length, prefix);
6465           length += strlen (prefix);
6466           strcpy (buffer + length, tree_code_name[code]);
6467           length += strlen (tree_code_name[code]);
6468         }
6469       va_end (args);
6470     }
6471   else
6472     buffer = (char *)"unexpected node";
6473
6474   internal_error ("tree check: %s, have %s in %s, at %s:%d",
6475                   buffer, tree_code_name[TREE_CODE (node)],
6476                   function, trim_filename (file), line);
6477 }
6478
6479 /* Complain that the tree code of NODE does match the expected 0
6480    terminated list of trailing codes. FILE, LINE, and FUNCTION are of
6481    the caller.  */
6482
6483 void
6484 tree_not_check_failed (const tree node, const char *file,
6485                        int line, const char *function, ...)
6486 {
6487   va_list args;
6488   char *buffer;
6489   unsigned length = 0;
6490   int code;
6491
6492   va_start (args, function);
6493   while ((code = va_arg (args, int)))
6494     length += 4 + strlen (tree_code_name[code]);
6495   va_end (args);
6496   va_start (args, function);
6497   buffer = alloca (length);
6498   length = 0;
6499   while ((code = va_arg (args, int)))
6500     {
6501       if (length)
6502         {
6503           strcpy (buffer + length, " or ");
6504           length += 4;
6505         }
6506       strcpy (buffer + length, tree_code_name[code]);
6507       length += strlen (tree_code_name[code]);
6508     }
6509   va_end (args);
6510
6511   internal_error ("tree check: expected none of %s, have %s in %s, at %s:%d",
6512                   buffer, tree_code_name[TREE_CODE (node)],
6513                   function, trim_filename (file), line);
6514 }
6515
6516 /* Similar to tree_check_failed, except that we check for a class of tree
6517    code, given in CL.  */
6518
6519 void
6520 tree_class_check_failed (const tree node, const enum tree_code_class cl,
6521                          const char *file, int line, const char *function)
6522 {
6523   internal_error
6524     ("tree check: expected class %qs, have %qs (%s) in %s, at %s:%d",
6525      TREE_CODE_CLASS_STRING (cl),
6526      TREE_CODE_CLASS_STRING (TREE_CODE_CLASS (TREE_CODE (node))),
6527      tree_code_name[TREE_CODE (node)], function, trim_filename (file), line);
6528 }
6529
6530 /* Similar to tree_check_failed, except that instead of specifying a
6531    dozen codes, use the knowledge that they're all sequential.  */
6532
6533 void
6534 tree_range_check_failed (const tree node, const char *file, int line,
6535                          const char *function, enum tree_code c1,
6536                          enum tree_code c2)
6537 {
6538   char *buffer;
6539   unsigned length = 0;
6540   enum tree_code c;
6541
6542   for (c = c1; c <= c2; ++c)
6543     length += 4 + strlen (tree_code_name[c]);
6544
6545   length += strlen ("expected ");
6546   buffer = alloca (length);
6547   length = 0;
6548
6549   for (c = c1; c <= c2; ++c)
6550     {
6551       const char *prefix = length ? " or " : "expected ";
6552
6553       strcpy (buffer + length, prefix);
6554       length += strlen (prefix);
6555       strcpy (buffer + length, tree_code_name[c]);
6556       length += strlen (tree_code_name[c]);
6557     }
6558
6559   internal_error ("tree check: %s, have %s in %s, at %s:%d",
6560                   buffer, tree_code_name[TREE_CODE (node)],
6561                   function, trim_filename (file), line);
6562 }
6563
6564
6565 /* Similar to tree_check_failed, except that we check that a tree does
6566    not have the specified code, given in CL.  */
6567
6568 void
6569 tree_not_class_check_failed (const tree node, const enum tree_code_class cl,
6570                              const char *file, int line, const char *function)
6571 {
6572   internal_error
6573     ("tree check: did not expect class %qs, have %qs (%s) in %s, at %s:%d",
6574      TREE_CODE_CLASS_STRING (cl),
6575      TREE_CODE_CLASS_STRING (TREE_CODE_CLASS (TREE_CODE (node))),
6576      tree_code_name[TREE_CODE (node)], function, trim_filename (file), line);
6577 }
6578
6579
6580 /* Similar to tree_check_failed but applied to OMP_CLAUSE codes.  */
6581
6582 void
6583 omp_clause_check_failed (const tree node, const char *file, int line,
6584                          const char *function, enum omp_clause_code code)
6585 {
6586   internal_error ("tree check: expected omp_clause %s, have %s in %s, at %s:%d",
6587                   omp_clause_code_name[code], tree_code_name[TREE_CODE (node)],
6588                   function, trim_filename (file), line);
6589 }
6590
6591
6592 /* Similar to tree_range_check_failed but applied to OMP_CLAUSE codes.  */
6593
6594 void
6595 omp_clause_range_check_failed (const tree node, const char *file, int line,
6596                                const char *function, enum omp_clause_code c1,
6597                                enum omp_clause_code c2)
6598 {
6599   char *buffer;
6600   unsigned length = 0;
6601   enum omp_clause_code c;
6602
6603   for (c = c1; c <= c2; ++c)
6604     length += 4 + strlen (omp_clause_code_name[c]);
6605
6606   length += strlen ("expected ");
6607   buffer = alloca (length);
6608   length = 0;
6609
6610   for (c = c1; c <= c2; ++c)
6611     {
6612       const char *prefix = length ? " or " : "expected ";
6613
6614       strcpy (buffer + length, prefix);
6615       length += strlen (prefix);
6616       strcpy (buffer + length, omp_clause_code_name[c]);
6617       length += strlen (omp_clause_code_name[c]);
6618     }
6619
6620   internal_error ("tree check: %s, have %s in %s, at %s:%d",
6621                   buffer, omp_clause_code_name[TREE_CODE (node)],
6622                   function, trim_filename (file), line);
6623 }
6624
6625
6626 #undef DEFTREESTRUCT
6627 #define DEFTREESTRUCT(VAL, NAME) NAME,
6628
6629 static const char *ts_enum_names[] = {
6630 #include "treestruct.def"
6631 };
6632 #undef DEFTREESTRUCT
6633
6634 #define TS_ENUM_NAME(EN) (ts_enum_names[(EN)])
6635
6636 /* Similar to tree_class_check_failed, except that we check for
6637    whether CODE contains the tree structure identified by EN.  */
6638
6639 void
6640 tree_contains_struct_check_failed (const tree node,
6641                                    const enum tree_node_structure_enum en,
6642                                    const char *file, int line,
6643                                    const char *function)
6644 {
6645   internal_error
6646     ("tree check: expected tree that contains %qs structure, have %qs  in %s, at %s:%d",
6647      TS_ENUM_NAME(en),
6648      tree_code_name[TREE_CODE (node)], function, trim_filename (file), line);
6649 }
6650
6651
6652 /* Similar to above, except that the check is for the bounds of a TREE_VEC's
6653    (dynamically sized) vector.  */
6654
6655 void
6656 tree_vec_elt_check_failed (int idx, int len, const char *file, int line,
6657                            const char *function)
6658 {
6659   internal_error
6660     ("tree check: accessed elt %d of tree_vec with %d elts in %s, at %s:%d",
6661      idx + 1, len, function, trim_filename (file), line);
6662 }
6663
6664 /* Similar to above, except that the check is for the bounds of a PHI_NODE's
6665    (dynamically sized) vector.  */
6666
6667 void
6668 phi_node_elt_check_failed (int idx, int len, const char *file, int line,
6669                             const char *function)
6670 {
6671   internal_error
6672     ("tree check: accessed elt %d of phi_node with %d elts in %s, at %s:%d",
6673      idx + 1, len, function, trim_filename (file), line);
6674 }
6675
6676 /* Similar to above, except that the check is for the bounds of the operand
6677    vector of an expression node.  */
6678
6679 void
6680 tree_operand_check_failed (int idx, enum tree_code code, const char *file,
6681                            int line, const char *function)
6682 {
6683   internal_error
6684     ("tree check: accessed operand %d of %s with %d operands in %s, at %s:%d",
6685      idx + 1, tree_code_name[code], TREE_CODE_LENGTH (code),
6686      function, trim_filename (file), line);
6687 }
6688
6689 /* Similar to above, except that the check is for the number of
6690    operands of an OMP_CLAUSE node.  */
6691
6692 void
6693 omp_clause_operand_check_failed (int idx, tree t, const char *file,
6694                                  int line, const char *function)
6695 {
6696   internal_error
6697     ("tree check: accessed operand %d of omp_clause %s with %d operands "
6698      "in %s, at %s:%d", idx + 1, omp_clause_code_name[OMP_CLAUSE_CODE (t)],
6699      omp_clause_num_ops [OMP_CLAUSE_CODE (t)], function,
6700      trim_filename (file), line);
6701 }
6702 #endif /* ENABLE_TREE_CHECKING */
6703 \f
6704 /* Create a new vector type node holding SUBPARTS units of type INNERTYPE,
6705    and mapped to the machine mode MODE.  Initialize its fields and build
6706    the information necessary for debugging output.  */
6707
6708 static tree
6709 make_vector_type (tree innertype, int nunits, enum machine_mode mode)
6710 {
6711   tree t;
6712   hashval_t hashcode = 0;
6713
6714   /* Build a main variant, based on the main variant of the inner type, then
6715      use it to build the variant we return.  */
6716   if ((TYPE_ATTRIBUTES (innertype) || TYPE_QUALS (innertype))
6717       && TYPE_MAIN_VARIANT (innertype) != innertype)
6718     return build_type_attribute_qual_variant (
6719             make_vector_type (TYPE_MAIN_VARIANT (innertype), nunits, mode),
6720             TYPE_ATTRIBUTES (innertype),
6721             TYPE_QUALS (innertype));
6722
6723   t = make_node (VECTOR_TYPE);
6724   TREE_TYPE (t) = TYPE_MAIN_VARIANT (innertype);
6725   SET_TYPE_VECTOR_SUBPARTS (t, nunits);
6726   TYPE_MODE (t) = mode;
6727   TYPE_READONLY (t) = TYPE_READONLY (innertype);
6728   TYPE_VOLATILE (t) = TYPE_VOLATILE (innertype);
6729
6730   if (TYPE_STRUCTURAL_EQUALITY_P (innertype))
6731     SET_TYPE_STRUCTURAL_EQUALITY (t);
6732   else if (TYPE_CANONICAL (innertype) != innertype
6733            || mode != VOIDmode)
6734     TYPE_CANONICAL (t)
6735       = make_vector_type (TYPE_CANONICAL (innertype), nunits, VOIDmode);
6736
6737   layout_type (t);
6738
6739   {
6740     tree index = build_int_cst (NULL_TREE, nunits - 1);
6741     tree array = build_array_type (innertype, build_index_type (index));
6742     tree rt = make_node (RECORD_TYPE);
6743
6744     TYPE_FIELDS (rt) = build_decl (FIELD_DECL, get_identifier ("f"), array);
6745     DECL_CONTEXT (TYPE_FIELDS (rt)) = rt;
6746     layout_type (rt);
6747     TYPE_DEBUG_REPRESENTATION_TYPE (t) = rt;
6748     /* In dwarfout.c, type lookup uses TYPE_UID numbers.  We want to output
6749        the representation type, and we want to find that die when looking up
6750        the vector type.  This is most easily achieved by making the TYPE_UID
6751        numbers equal.  */
6752     TYPE_UID (rt) = TYPE_UID (t);
6753   }
6754
6755   hashcode = iterative_hash_host_wide_int (VECTOR_TYPE, hashcode);
6756   hashcode = iterative_hash_host_wide_int (mode, hashcode);
6757   hashcode = iterative_hash_object (TYPE_HASH (innertype), hashcode);
6758   return type_hash_canon (hashcode, t);
6759 }
6760
6761 static tree
6762 make_or_reuse_type (unsigned size, int unsignedp)
6763 {
6764   if (size == INT_TYPE_SIZE)
6765     return unsignedp ? unsigned_type_node : integer_type_node;
6766   if (size == CHAR_TYPE_SIZE)
6767     return unsignedp ? unsigned_char_type_node : signed_char_type_node;
6768   if (size == SHORT_TYPE_SIZE)
6769     return unsignedp ? short_unsigned_type_node : short_integer_type_node;
6770   if (size == LONG_TYPE_SIZE)
6771     return unsignedp ? long_unsigned_type_node : long_integer_type_node;
6772   if (size == LONG_LONG_TYPE_SIZE)
6773     return (unsignedp ? long_long_unsigned_type_node
6774             : long_long_integer_type_node);
6775
6776   if (unsignedp)
6777     return make_unsigned_type (size);
6778   else
6779     return make_signed_type (size);
6780 }
6781
6782 /* Create nodes for all integer types (and error_mark_node) using the sizes
6783    of C datatypes.  The caller should call set_sizetype soon after calling
6784    this function to select one of the types as sizetype.  */
6785
6786 void
6787 build_common_tree_nodes (bool signed_char, bool signed_sizetype)
6788 {
6789   error_mark_node = make_node (ERROR_MARK);
6790   TREE_TYPE (error_mark_node) = error_mark_node;
6791
6792   initialize_sizetypes (signed_sizetype);
6793
6794   /* Define both `signed char' and `unsigned char'.  */
6795   signed_char_type_node = make_signed_type (CHAR_TYPE_SIZE);
6796   TYPE_STRING_FLAG (signed_char_type_node) = 1;
6797   unsigned_char_type_node = make_unsigned_type (CHAR_TYPE_SIZE);
6798   TYPE_STRING_FLAG (unsigned_char_type_node) = 1;
6799
6800   /* Define `char', which is like either `signed char' or `unsigned char'
6801      but not the same as either.  */
6802   char_type_node
6803     = (signed_char
6804        ? make_signed_type (CHAR_TYPE_SIZE)
6805        : make_unsigned_type (CHAR_TYPE_SIZE));
6806   TYPE_STRING_FLAG (char_type_node) = 1;
6807
6808   short_integer_type_node = make_signed_type (SHORT_TYPE_SIZE);
6809   short_unsigned_type_node = make_unsigned_type (SHORT_TYPE_SIZE);
6810   integer_type_node = make_signed_type (INT_TYPE_SIZE);
6811   unsigned_type_node = make_unsigned_type (INT_TYPE_SIZE);
6812   long_integer_type_node = make_signed_type (LONG_TYPE_SIZE);
6813   long_unsigned_type_node = make_unsigned_type (LONG_TYPE_SIZE);
6814   long_long_integer_type_node = make_signed_type (LONG_LONG_TYPE_SIZE);
6815   long_long_unsigned_type_node = make_unsigned_type (LONG_LONG_TYPE_SIZE);
6816
6817   /* Define a boolean type.  This type only represents boolean values but
6818      may be larger than char depending on the value of BOOL_TYPE_SIZE.
6819      Front ends which want to override this size (i.e. Java) can redefine
6820      boolean_type_node before calling build_common_tree_nodes_2.  */
6821   boolean_type_node = make_unsigned_type (BOOL_TYPE_SIZE);
6822   TREE_SET_CODE (boolean_type_node, BOOLEAN_TYPE);
6823   TYPE_MAX_VALUE (boolean_type_node) = build_int_cst (boolean_type_node, 1);
6824   TYPE_PRECISION (boolean_type_node) = 1;
6825
6826   /* Fill in the rest of the sized types.  Reuse existing type nodes
6827      when possible.  */
6828   intQI_type_node = make_or_reuse_type (GET_MODE_BITSIZE (QImode), 0);
6829   intHI_type_node = make_or_reuse_type (GET_MODE_BITSIZE (HImode), 0);
6830   intSI_type_node = make_or_reuse_type (GET_MODE_BITSIZE (SImode), 0);
6831   intDI_type_node = make_or_reuse_type (GET_MODE_BITSIZE (DImode), 0);
6832   intTI_type_node = make_or_reuse_type (GET_MODE_BITSIZE (TImode), 0);
6833
6834   unsigned_intQI_type_node = make_or_reuse_type (GET_MODE_BITSIZE (QImode), 1);
6835   unsigned_intHI_type_node = make_or_reuse_type (GET_MODE_BITSIZE (HImode), 1);
6836   unsigned_intSI_type_node = make_or_reuse_type (GET_MODE_BITSIZE (SImode), 1);
6837   unsigned_intDI_type_node = make_or_reuse_type (GET_MODE_BITSIZE (DImode), 1);
6838   unsigned_intTI_type_node = make_or_reuse_type (GET_MODE_BITSIZE (TImode), 1);
6839
6840   access_public_node = get_identifier ("public");
6841   access_protected_node = get_identifier ("protected");
6842   access_private_node = get_identifier ("private");
6843 }
6844
6845 /* Call this function after calling build_common_tree_nodes and set_sizetype.
6846    It will create several other common tree nodes.  */
6847
6848 void
6849 build_common_tree_nodes_2 (int short_double)
6850 {
6851   /* Define these next since types below may used them.  */
6852   integer_zero_node = build_int_cst (NULL_TREE, 0);
6853   integer_one_node = build_int_cst (NULL_TREE, 1);
6854   integer_minus_one_node = build_int_cst (NULL_TREE, -1);
6855
6856   size_zero_node = size_int (0);
6857   size_one_node = size_int (1);
6858   bitsize_zero_node = bitsize_int (0);
6859   bitsize_one_node = bitsize_int (1);
6860   bitsize_unit_node = bitsize_int (BITS_PER_UNIT);
6861
6862   boolean_false_node = TYPE_MIN_VALUE (boolean_type_node);
6863   boolean_true_node = TYPE_MAX_VALUE (boolean_type_node);
6864
6865   void_type_node = make_node (VOID_TYPE);
6866   layout_type (void_type_node);
6867
6868   /* We are not going to have real types in C with less than byte alignment,
6869      so we might as well not have any types that claim to have it.  */
6870   TYPE_ALIGN (void_type_node) = BITS_PER_UNIT;
6871   TYPE_USER_ALIGN (void_type_node) = 0;
6872
6873   null_pointer_node = build_int_cst (build_pointer_type (void_type_node), 0);
6874   layout_type (TREE_TYPE (null_pointer_node));
6875
6876   ptr_type_node = build_pointer_type (void_type_node);
6877   const_ptr_type_node
6878     = build_pointer_type (build_type_variant (void_type_node, 1, 0));
6879   fileptr_type_node = ptr_type_node;
6880
6881   float_type_node = make_node (REAL_TYPE);
6882   TYPE_PRECISION (float_type_node) = FLOAT_TYPE_SIZE;
6883   layout_type (float_type_node);
6884
6885   double_type_node = make_node (REAL_TYPE);
6886   if (short_double)
6887     TYPE_PRECISION (double_type_node) = FLOAT_TYPE_SIZE;
6888   else
6889     TYPE_PRECISION (double_type_node) = DOUBLE_TYPE_SIZE;
6890   layout_type (double_type_node);
6891
6892   long_double_type_node = make_node (REAL_TYPE);
6893   TYPE_PRECISION (long_double_type_node) = LONG_DOUBLE_TYPE_SIZE;
6894   layout_type (long_double_type_node);
6895
6896   float_ptr_type_node = build_pointer_type (float_type_node);
6897   double_ptr_type_node = build_pointer_type (double_type_node);
6898   long_double_ptr_type_node = build_pointer_type (long_double_type_node);
6899   integer_ptr_type_node = build_pointer_type (integer_type_node);
6900
6901   /* Fixed size integer types.  */
6902   uint32_type_node = build_nonstandard_integer_type (32, true);
6903   uint64_type_node = build_nonstandard_integer_type (64, true);
6904
6905   /* Decimal float types. */
6906   dfloat32_type_node = make_node (REAL_TYPE);
6907   TYPE_PRECISION (dfloat32_type_node) = DECIMAL32_TYPE_SIZE;
6908   layout_type (dfloat32_type_node);
6909   TYPE_MODE (dfloat32_type_node) = SDmode;
6910   dfloat32_ptr_type_node = build_pointer_type (dfloat32_type_node);
6911
6912   dfloat64_type_node = make_node (REAL_TYPE);
6913   TYPE_PRECISION (dfloat64_type_node) = DECIMAL64_TYPE_SIZE;
6914   layout_type (dfloat64_type_node);
6915   TYPE_MODE (dfloat64_type_node) = DDmode;
6916   dfloat64_ptr_type_node = build_pointer_type (dfloat64_type_node);
6917
6918   dfloat128_type_node = make_node (REAL_TYPE);
6919   TYPE_PRECISION (dfloat128_type_node) = DECIMAL128_TYPE_SIZE;
6920   layout_type (dfloat128_type_node);
6921   TYPE_MODE (dfloat128_type_node) = TDmode;
6922   dfloat128_ptr_type_node = build_pointer_type (dfloat128_type_node);
6923
6924   complex_integer_type_node = make_node (COMPLEX_TYPE);
6925   TREE_TYPE (complex_integer_type_node) = integer_type_node;
6926   layout_type (complex_integer_type_node);
6927
6928   complex_float_type_node = make_node (COMPLEX_TYPE);
6929   TREE_TYPE (complex_float_type_node) = float_type_node;
6930   layout_type (complex_float_type_node);
6931
6932   complex_double_type_node = make_node (COMPLEX_TYPE);
6933   TREE_TYPE (complex_double_type_node) = double_type_node;
6934   layout_type (complex_double_type_node);
6935
6936   complex_long_double_type_node = make_node (COMPLEX_TYPE);
6937   TREE_TYPE (complex_long_double_type_node) = long_double_type_node;
6938   layout_type (complex_long_double_type_node);
6939
6940   {
6941     tree t = targetm.build_builtin_va_list ();
6942
6943     /* Many back-ends define record types without setting TYPE_NAME.
6944        If we copied the record type here, we'd keep the original
6945        record type without a name.  This breaks name mangling.  So,
6946        don't copy record types and let c_common_nodes_and_builtins()
6947        declare the type to be __builtin_va_list.  */
6948     if (TREE_CODE (t) != RECORD_TYPE)
6949       t = build_variant_type_copy (t);
6950
6951     va_list_type_node = t;
6952   }
6953 }
6954
6955 /* A subroutine of build_common_builtin_nodes.  Define a builtin function.  */
6956
6957 static void
6958 local_define_builtin (const char *name, tree type, enum built_in_function code,
6959                       const char *library_name, int ecf_flags)
6960 {
6961   tree decl;
6962
6963   decl = add_builtin_function (name, type, code, BUILT_IN_NORMAL,
6964                                library_name, NULL_TREE);
6965   if (ecf_flags & ECF_CONST)
6966     TREE_READONLY (decl) = 1;
6967   if (ecf_flags & ECF_PURE)
6968     DECL_IS_PURE (decl) = 1;
6969   if (ecf_flags & ECF_NORETURN)
6970     TREE_THIS_VOLATILE (decl) = 1;
6971   if (ecf_flags & ECF_NOTHROW)
6972     TREE_NOTHROW (decl) = 1;
6973   if (ecf_flags & ECF_MALLOC)
6974     DECL_IS_MALLOC (decl) = 1;
6975
6976   built_in_decls[code] = decl;
6977   implicit_built_in_decls[code] = decl;
6978 }
6979
6980 /* Call this function after instantiating all builtins that the language
6981    front end cares about.  This will build the rest of the builtins that
6982    are relied upon by the tree optimizers and the middle-end.  */
6983
6984 void
6985 build_common_builtin_nodes (void)
6986 {
6987   tree tmp, ftype;
6988
6989   if (built_in_decls[BUILT_IN_MEMCPY] == NULL
6990       || built_in_decls[BUILT_IN_MEMMOVE] == NULL)
6991     {
6992       tmp = tree_cons (NULL_TREE, size_type_node, void_list_node);
6993       tmp = tree_cons (NULL_TREE, const_ptr_type_node, tmp);
6994       tmp = tree_cons (NULL_TREE, ptr_type_node, tmp);
6995       ftype = build_function_type (ptr_type_node, tmp);
6996
6997       if (built_in_decls[BUILT_IN_MEMCPY] == NULL)
6998         local_define_builtin ("__builtin_memcpy", ftype, BUILT_IN_MEMCPY,
6999                               "memcpy", ECF_NOTHROW);
7000       if (built_in_decls[BUILT_IN_MEMMOVE] == NULL)
7001         local_define_builtin ("__builtin_memmove", ftype, BUILT_IN_MEMMOVE,
7002                               "memmove", ECF_NOTHROW);
7003     }
7004
7005   if (built_in_decls[BUILT_IN_MEMCMP] == NULL)
7006     {
7007       tmp = tree_cons (NULL_TREE, size_type_node, void_list_node);
7008       tmp = tree_cons (NULL_TREE, const_ptr_type_node, tmp);
7009       tmp = tree_cons (NULL_TREE, const_ptr_type_node, tmp);
7010       ftype = build_function_type (integer_type_node, tmp);
7011       local_define_builtin ("__builtin_memcmp", ftype, BUILT_IN_MEMCMP,
7012                             "memcmp", ECF_PURE | ECF_NOTHROW);
7013     }
7014
7015   if (built_in_decls[BUILT_IN_MEMSET] == NULL)
7016     {
7017       tmp = tree_cons (NULL_TREE, size_type_node, void_list_node);
7018       tmp = tree_cons (NULL_TREE, integer_type_node, tmp);
7019       tmp = tree_cons (NULL_TREE, ptr_type_node, tmp);
7020       ftype = build_function_type (ptr_type_node, tmp);
7021       local_define_builtin ("__builtin_memset", ftype, BUILT_IN_MEMSET,
7022                             "memset", ECF_NOTHROW);
7023     }
7024
7025   if (built_in_decls[BUILT_IN_ALLOCA] == NULL)
7026     {
7027       tmp = tree_cons (NULL_TREE, size_type_node, void_list_node);
7028       ftype = build_function_type (ptr_type_node, tmp);
7029       local_define_builtin ("__builtin_alloca", ftype, BUILT_IN_ALLOCA,
7030                             "alloca", ECF_NOTHROW | ECF_MALLOC);
7031     }
7032
7033   tmp = tree_cons (NULL_TREE, ptr_type_node, void_list_node);
7034   tmp = tree_cons (NULL_TREE, ptr_type_node, tmp);
7035   tmp = tree_cons (NULL_TREE, ptr_type_node, tmp);
7036   ftype = build_function_type (void_type_node, tmp);
7037   local_define_builtin ("__builtin_init_trampoline", ftype,
7038                         BUILT_IN_INIT_TRAMPOLINE,
7039                         "__builtin_init_trampoline", ECF_NOTHROW);
7040
7041   tmp = tree_cons (NULL_TREE, ptr_type_node, void_list_node);
7042   ftype = build_function_type (ptr_type_node, tmp);
7043   local_define_builtin ("__builtin_adjust_trampoline", ftype,
7044                         BUILT_IN_ADJUST_TRAMPOLINE,
7045                         "__builtin_adjust_trampoline",
7046                         ECF_CONST | ECF_NOTHROW);
7047
7048   tmp = tree_cons (NULL_TREE, ptr_type_node, void_list_node);
7049   tmp = tree_cons (NULL_TREE, ptr_type_node, tmp);
7050   ftype = build_function_type (void_type_node, tmp);
7051   local_define_builtin ("__builtin_nonlocal_goto", ftype,
7052                         BUILT_IN_NONLOCAL_GOTO,
7053                         "__builtin_nonlocal_goto",
7054                         ECF_NORETURN | ECF_NOTHROW);
7055
7056   tmp = tree_cons (NULL_TREE, ptr_type_node, void_list_node);
7057   tmp = tree_cons (NULL_TREE, ptr_type_node, tmp);
7058   ftype = build_function_type (void_type_node, tmp);
7059   local_define_builtin ("__builtin_setjmp_setup", ftype,
7060                         BUILT_IN_SETJMP_SETUP,
7061                         "__builtin_setjmp_setup", ECF_NOTHROW);
7062
7063   tmp = tree_cons (NULL_TREE, ptr_type_node, void_list_node);
7064   ftype = build_function_type (ptr_type_node, tmp);
7065   local_define_builtin ("__builtin_setjmp_dispatcher", ftype,
7066                         BUILT_IN_SETJMP_DISPATCHER,
7067                         "__builtin_setjmp_dispatcher",
7068                         ECF_PURE | ECF_NOTHROW);
7069
7070   tmp = tree_cons (NULL_TREE, ptr_type_node, void_list_node);
7071   ftype = build_function_type (void_type_node, tmp);
7072   local_define_builtin ("__builtin_setjmp_receiver", ftype,
7073                         BUILT_IN_SETJMP_RECEIVER,
7074                         "__builtin_setjmp_receiver", ECF_NOTHROW);
7075
7076   ftype = build_function_type (ptr_type_node, void_list_node);
7077   local_define_builtin ("__builtin_stack_save", ftype, BUILT_IN_STACK_SAVE,
7078                         "__builtin_stack_save", ECF_NOTHROW);
7079
7080   tmp = tree_cons (NULL_TREE, ptr_type_node, void_list_node);
7081   ftype = build_function_type (void_type_node, tmp);
7082   local_define_builtin ("__builtin_stack_restore", ftype,
7083                         BUILT_IN_STACK_RESTORE,
7084                         "__builtin_stack_restore", ECF_NOTHROW);
7085
7086   ftype = build_function_type (void_type_node, void_list_node);
7087   local_define_builtin ("__builtin_profile_func_enter", ftype,
7088                         BUILT_IN_PROFILE_FUNC_ENTER, "profile_func_enter", 0);
7089   local_define_builtin ("__builtin_profile_func_exit", ftype,
7090                         BUILT_IN_PROFILE_FUNC_EXIT, "profile_func_exit", 0);
7091
7092   /* Complex multiplication and division.  These are handled as builtins
7093      rather than optabs because emit_library_call_value doesn't support
7094      complex.  Further, we can do slightly better with folding these
7095      beasties if the real and complex parts of the arguments are separate.  */
7096   {
7097     enum machine_mode mode;
7098
7099     for (mode = MIN_MODE_COMPLEX_FLOAT; mode <= MAX_MODE_COMPLEX_FLOAT; ++mode)
7100       {
7101         char mode_name_buf[4], *q;
7102         const char *p;
7103         enum built_in_function mcode, dcode;
7104         tree type, inner_type;
7105
7106         type = lang_hooks.types.type_for_mode (mode, 0);
7107         if (type == NULL)
7108           continue;
7109         inner_type = TREE_TYPE (type);
7110
7111         tmp = tree_cons (NULL_TREE, inner_type, void_list_node);
7112         tmp = tree_cons (NULL_TREE, inner_type, tmp);
7113         tmp = tree_cons (NULL_TREE, inner_type, tmp);
7114         tmp = tree_cons (NULL_TREE, inner_type, tmp);
7115         ftype = build_function_type (type, tmp);
7116
7117         mcode = BUILT_IN_COMPLEX_MUL_MIN + mode - MIN_MODE_COMPLEX_FLOAT;
7118         dcode = BUILT_IN_COMPLEX_DIV_MIN + mode - MIN_MODE_COMPLEX_FLOAT;
7119
7120         for (p = GET_MODE_NAME (mode), q = mode_name_buf; *p; p++, q++)
7121           *q = TOLOWER (*p);
7122         *q = '\0';
7123
7124         built_in_names[mcode] = concat ("__mul", mode_name_buf, "3", NULL);
7125         local_define_builtin (built_in_names[mcode], ftype, mcode,
7126                               built_in_names[mcode], ECF_CONST | ECF_NOTHROW);
7127
7128         built_in_names[dcode] = concat ("__div", mode_name_buf, "3", NULL);
7129         local_define_builtin (built_in_names[dcode], ftype, dcode,
7130                               built_in_names[dcode], ECF_CONST | ECF_NOTHROW);
7131       }
7132   }
7133 }
7134
7135 /* HACK.  GROSS.  This is absolutely disgusting.  I wish there was a
7136    better way.
7137
7138    If we requested a pointer to a vector, build up the pointers that
7139    we stripped off while looking for the inner type.  Similarly for
7140    return values from functions.
7141
7142    The argument TYPE is the top of the chain, and BOTTOM is the
7143    new type which we will point to.  */
7144
7145 tree
7146 reconstruct_complex_type (tree type, tree bottom)
7147 {
7148   tree inner, outer;
7149
7150   if (POINTER_TYPE_P (type))
7151     {
7152       inner = reconstruct_complex_type (TREE_TYPE (type), bottom);
7153       outer = build_pointer_type (inner);
7154     }
7155   else if (TREE_CODE (type) == ARRAY_TYPE)
7156     {
7157       inner = reconstruct_complex_type (TREE_TYPE (type), bottom);
7158       outer = build_array_type (inner, TYPE_DOMAIN (type));
7159     }
7160   else if (TREE_CODE (type) == FUNCTION_TYPE)
7161     {
7162       inner = reconstruct_complex_type (TREE_TYPE (type), bottom);
7163       outer = build_function_type (inner, TYPE_ARG_TYPES (type));
7164     }
7165   else if (TREE_CODE (type) == METHOD_TYPE)
7166     {
7167       tree argtypes;
7168       inner = reconstruct_complex_type (TREE_TYPE (type), bottom);
7169       /* The build_method_type_directly() routine prepends 'this' to argument list,
7170          so we must compensate by getting rid of it.  */
7171       argtypes = TYPE_ARG_TYPES (type);
7172       outer = build_method_type_directly (TYPE_METHOD_BASETYPE (type),
7173                                           inner,
7174                                           TYPE_ARG_TYPES (type));
7175       TYPE_ARG_TYPES (outer) = argtypes;
7176     }
7177   else
7178     return bottom;
7179
7180   TYPE_READONLY (outer) = TYPE_READONLY (type);
7181   TYPE_VOLATILE (outer) = TYPE_VOLATILE (type);
7182
7183   return outer;
7184 }
7185
7186 /* Returns a vector tree node given a mode (integer, vector, or BLKmode) and
7187    the inner type.  */
7188 tree
7189 build_vector_type_for_mode (tree innertype, enum machine_mode mode)
7190 {
7191   int nunits;
7192
7193   switch (GET_MODE_CLASS (mode))
7194     {
7195     case MODE_VECTOR_INT:
7196     case MODE_VECTOR_FLOAT:
7197       nunits = GET_MODE_NUNITS (mode);
7198       break;
7199
7200     case MODE_INT:
7201       /* Check that there are no leftover bits.  */
7202       gcc_assert (GET_MODE_BITSIZE (mode)
7203                   % TREE_INT_CST_LOW (TYPE_SIZE (innertype)) == 0);
7204
7205       nunits = GET_MODE_BITSIZE (mode)
7206                / TREE_INT_CST_LOW (TYPE_SIZE (innertype));
7207       break;
7208
7209     default:
7210       gcc_unreachable ();
7211     }
7212
7213   return make_vector_type (innertype, nunits, mode);
7214 }
7215
7216 /* Similarly, but takes the inner type and number of units, which must be
7217    a power of two.  */
7218
7219 tree
7220 build_vector_type (tree innertype, int nunits)
7221 {
7222   return make_vector_type (innertype, nunits, VOIDmode);
7223 }
7224
7225
7226 /* Build RESX_EXPR with given REGION_NUMBER.  */
7227 tree
7228 build_resx (int region_number)
7229 {
7230   tree t;
7231   t = build1 (RESX_EXPR, void_type_node,
7232               build_int_cst (NULL_TREE, region_number));
7233   return t;
7234 }
7235
7236 /* Given an initializer INIT, return TRUE if INIT is zero or some
7237    aggregate of zeros.  Otherwise return FALSE.  */
7238 bool
7239 initializer_zerop (tree init)
7240 {
7241   tree elt;
7242
7243   STRIP_NOPS (init);
7244
7245   switch (TREE_CODE (init))
7246     {
7247     case INTEGER_CST:
7248       return integer_zerop (init);
7249
7250     case REAL_CST:
7251       /* ??? Note that this is not correct for C4X float formats.  There,
7252          a bit pattern of all zeros is 1.0; 0.0 is encoded with the most
7253          negative exponent.  */
7254       return real_zerop (init)
7255         && ! REAL_VALUE_MINUS_ZERO (TREE_REAL_CST (init));
7256
7257     case COMPLEX_CST:
7258       return integer_zerop (init)
7259         || (real_zerop (init)
7260             && ! REAL_VALUE_MINUS_ZERO (TREE_REAL_CST (TREE_REALPART (init)))
7261             && ! REAL_VALUE_MINUS_ZERO (TREE_REAL_CST (TREE_IMAGPART (init))));
7262
7263     case VECTOR_CST:
7264       for (elt = TREE_VECTOR_CST_ELTS (init); elt; elt = TREE_CHAIN (elt))
7265         if (!initializer_zerop (TREE_VALUE (elt)))
7266           return false;
7267       return true;
7268
7269     case CONSTRUCTOR:
7270       {
7271         unsigned HOST_WIDE_INT idx;
7272
7273         FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (init), idx, elt)
7274           if (!initializer_zerop (elt))
7275             return false;
7276         return true;
7277       }
7278
7279     default:
7280       return false;
7281     }
7282 }
7283
7284 /* Build an empty statement.  */
7285
7286 tree
7287 build_empty_stmt (void)
7288 {
7289   return build1 (NOP_EXPR, void_type_node, size_zero_node);
7290 }
7291
7292
7293 /* Build an OpenMP clause with code CODE.  */
7294
7295 tree
7296 build_omp_clause (enum omp_clause_code code)
7297 {
7298   tree t;
7299   int size, length;
7300
7301   length = omp_clause_num_ops[code];
7302   size = (sizeof (struct tree_omp_clause) + (length - 1) * sizeof (tree));
7303
7304   t = ggc_alloc (size);
7305   memset (t, 0, size);
7306   TREE_SET_CODE (t, OMP_CLAUSE);
7307   OMP_CLAUSE_SET_CODE (t, code);
7308
7309 #ifdef GATHER_STATISTICS
7310   tree_node_counts[(int) omp_clause_kind]++;
7311   tree_node_sizes[(int) omp_clause_kind] += size;
7312 #endif
7313
7314   return t;
7315 }
7316
7317
7318 /* Returns true if it is possible to prove that the index of
7319    an array access REF (an ARRAY_REF expression) falls into the
7320    array bounds.  */
7321
7322 bool
7323 in_array_bounds_p (tree ref)
7324 {
7325   tree idx = TREE_OPERAND (ref, 1);
7326   tree min, max;
7327
7328   if (TREE_CODE (idx) != INTEGER_CST)
7329     return false;
7330
7331   min = array_ref_low_bound (ref);
7332   max = array_ref_up_bound (ref);
7333   if (!min
7334       || !max
7335       || TREE_CODE (min) != INTEGER_CST
7336       || TREE_CODE (max) != INTEGER_CST)
7337     return false;
7338
7339   if (tree_int_cst_lt (idx, min)
7340       || tree_int_cst_lt (max, idx))
7341     return false;
7342
7343   return true;
7344 }
7345
7346 /* Returns true if it is possible to prove that the range of
7347    an array access REF (an ARRAY_RANGE_REF expression) falls
7348    into the array bounds.  */
7349
7350 bool
7351 range_in_array_bounds_p (tree ref)
7352 {
7353   tree domain_type = TYPE_DOMAIN (TREE_TYPE (ref));
7354   tree range_min, range_max, min, max;
7355
7356   range_min = TYPE_MIN_VALUE (domain_type);
7357   range_max = TYPE_MAX_VALUE (domain_type);
7358   if (!range_min
7359       || !range_max
7360       || TREE_CODE (range_min) != INTEGER_CST
7361       || TREE_CODE (range_max) != INTEGER_CST)
7362     return false;
7363
7364   min = array_ref_low_bound (ref);
7365   max = array_ref_up_bound (ref);
7366   if (!min
7367       || !max
7368       || TREE_CODE (min) != INTEGER_CST
7369       || TREE_CODE (max) != INTEGER_CST)
7370     return false;
7371
7372   if (tree_int_cst_lt (range_min, min)
7373       || tree_int_cst_lt (max, range_max))
7374     return false;
7375
7376   return true;
7377 }
7378
7379 /* Return true if T (assumed to be a DECL) is a global variable.  */
7380
7381 bool
7382 is_global_var (tree t)
7383 {
7384   if (MTAG_P (t))
7385     return (TREE_STATIC (t) || MTAG_GLOBAL (t));
7386   else
7387     return (TREE_STATIC (t) || DECL_EXTERNAL (t));
7388 }
7389
7390 /* Return true if T (assumed to be a DECL) must be assigned a memory
7391    location.  */
7392
7393 bool
7394 needs_to_live_in_memory (tree t)
7395 {
7396   if (TREE_CODE (t) == SSA_NAME)
7397     t = SSA_NAME_VAR (t);
7398
7399   return (TREE_ADDRESSABLE (t)
7400           || is_global_var (t)
7401           || (TREE_CODE (t) == RESULT_DECL
7402               && aggregate_value_p (t, current_function_decl)));
7403 }
7404
7405 /* There are situations in which a language considers record types
7406    compatible which have different field lists.  Decide if two fields
7407    are compatible.  It is assumed that the parent records are compatible.  */
7408
7409 bool
7410 fields_compatible_p (tree f1, tree f2)
7411 {
7412   if (!operand_equal_p (DECL_FIELD_BIT_OFFSET (f1),
7413                         DECL_FIELD_BIT_OFFSET (f2), OEP_ONLY_CONST))
7414     return false;
7415
7416   if (!operand_equal_p (DECL_FIELD_OFFSET (f1),
7417                         DECL_FIELD_OFFSET (f2), OEP_ONLY_CONST))
7418     return false;
7419
7420   if (!lang_hooks.types_compatible_p (TREE_TYPE (f1), TREE_TYPE (f2)))
7421     return false;
7422
7423   return true;
7424 }
7425
7426 /* Locate within RECORD a field that is compatible with ORIG_FIELD.  */
7427
7428 tree
7429 find_compatible_field (tree record, tree orig_field)
7430 {
7431   tree f;
7432
7433   for (f = TYPE_FIELDS (record); f ; f = TREE_CHAIN (f))
7434     if (TREE_CODE (f) == FIELD_DECL
7435         && fields_compatible_p (f, orig_field))
7436       return f;
7437
7438   /* ??? Why isn't this on the main fields list?  */
7439   f = TYPE_VFIELD (record);
7440   if (f && TREE_CODE (f) == FIELD_DECL
7441       && fields_compatible_p (f, orig_field))
7442     return f;
7443
7444   /* ??? We should abort here, but Java appears to do Bad Things
7445      with inherited fields.  */
7446   return orig_field;
7447 }
7448
7449 /* Return value of a constant X.  */
7450
7451 HOST_WIDE_INT
7452 int_cst_value (tree x)
7453 {
7454   unsigned bits = TYPE_PRECISION (TREE_TYPE (x));
7455   unsigned HOST_WIDE_INT val = TREE_INT_CST_LOW (x);
7456   bool negative = ((val >> (bits - 1)) & 1) != 0;
7457
7458   gcc_assert (bits <= HOST_BITS_PER_WIDE_INT);
7459
7460   if (negative)
7461     val |= (~(unsigned HOST_WIDE_INT) 0) << (bits - 1) << 1;
7462   else
7463     val &= ~((~(unsigned HOST_WIDE_INT) 0) << (bits - 1) << 1);
7464
7465   return val;
7466 }
7467
7468 /* Returns the greatest common divisor of A and B, which must be
7469    INTEGER_CSTs.  */
7470
7471 tree
7472 tree_fold_gcd (tree a, tree b)
7473 {
7474   tree a_mod_b;
7475   tree type = TREE_TYPE (a);
7476
7477   gcc_assert (TREE_CODE (a) == INTEGER_CST);
7478   gcc_assert (TREE_CODE (b) == INTEGER_CST);
7479
7480   if (integer_zerop (a))
7481     return b;
7482
7483   if (integer_zerop (b))
7484     return a;
7485
7486   if (tree_int_cst_sgn (a) == -1)
7487     a = fold_build2 (MULT_EXPR, type, a,
7488                      build_int_cst (type, -1));
7489
7490   if (tree_int_cst_sgn (b) == -1)
7491     b = fold_build2 (MULT_EXPR, type, b,
7492                      build_int_cst (type, -1));
7493
7494   while (1)
7495     {
7496       a_mod_b = fold_build2 (FLOOR_MOD_EXPR, type, a, b);
7497
7498       if (!TREE_INT_CST_LOW (a_mod_b)
7499           && !TREE_INT_CST_HIGH (a_mod_b))
7500         return b;
7501
7502       a = b;
7503       b = a_mod_b;
7504     }
7505 }
7506
7507 /* Returns unsigned variant of TYPE.  */
7508
7509 tree
7510 unsigned_type_for (tree type)
7511 {
7512   if (POINTER_TYPE_P (type))
7513     return lang_hooks.types.unsigned_type (size_type_node);
7514   return lang_hooks.types.unsigned_type (type);
7515 }
7516
7517 /* Returns signed variant of TYPE.  */
7518
7519 tree
7520 signed_type_for (tree type)
7521 {
7522   if (POINTER_TYPE_P (type))
7523     return lang_hooks.types.signed_type (size_type_node);
7524   return lang_hooks.types.signed_type (type);
7525 }
7526
7527 /* Returns the largest value obtainable by casting something in INNER type to
7528    OUTER type.  */
7529
7530 tree
7531 upper_bound_in_type (tree outer, tree inner)
7532 {
7533   unsigned HOST_WIDE_INT lo, hi;
7534   unsigned int det = 0;
7535   unsigned oprec = TYPE_PRECISION (outer);
7536   unsigned iprec = TYPE_PRECISION (inner);
7537   unsigned prec;
7538
7539   /* Compute a unique number for every combination.  */
7540   det |= (oprec > iprec) ? 4 : 0;
7541   det |= TYPE_UNSIGNED (outer) ? 2 : 0;
7542   det |= TYPE_UNSIGNED (inner) ? 1 : 0;
7543
7544   /* Determine the exponent to use.  */
7545   switch (det)
7546     {
7547     case 0:
7548     case 1:
7549       /* oprec <= iprec, outer: signed, inner: don't care.  */
7550       prec = oprec - 1;
7551       break;
7552     case 2:
7553     case 3:
7554       /* oprec <= iprec, outer: unsigned, inner: don't care.  */
7555       prec = oprec;
7556       break;
7557     case 4:
7558       /* oprec > iprec, outer: signed, inner: signed.  */
7559       prec = iprec - 1;
7560       break;
7561     case 5:
7562       /* oprec > iprec, outer: signed, inner: unsigned.  */
7563       prec = iprec;
7564       break;
7565     case 6:
7566       /* oprec > iprec, outer: unsigned, inner: signed.  */
7567       prec = oprec;
7568       break;
7569     case 7:
7570       /* oprec > iprec, outer: unsigned, inner: unsigned.  */
7571       prec = iprec;
7572       break;
7573     default:
7574       gcc_unreachable ();
7575     }
7576
7577   /* Compute 2^^prec - 1.  */
7578   if (prec <= HOST_BITS_PER_WIDE_INT)
7579     {
7580       hi = 0;
7581       lo = ((~(unsigned HOST_WIDE_INT) 0)
7582             >> (HOST_BITS_PER_WIDE_INT - prec));
7583     }
7584   else
7585     {
7586       hi = ((~(unsigned HOST_WIDE_INT) 0)
7587             >> (2 * HOST_BITS_PER_WIDE_INT - prec));
7588       lo = ~(unsigned HOST_WIDE_INT) 0;
7589     }
7590
7591   return build_int_cst_wide (outer, lo, hi);
7592 }
7593
7594 /* Returns the smallest value obtainable by casting something in INNER type to
7595    OUTER type.  */
7596
7597 tree
7598 lower_bound_in_type (tree outer, tree inner)
7599 {
7600   unsigned HOST_WIDE_INT lo, hi;
7601   unsigned oprec = TYPE_PRECISION (outer);
7602   unsigned iprec = TYPE_PRECISION (inner);
7603
7604   /* If OUTER type is unsigned, we can definitely cast 0 to OUTER type
7605      and obtain 0.  */
7606   if (TYPE_UNSIGNED (outer)
7607       /* If we are widening something of an unsigned type, OUTER type
7608          contains all values of INNER type.  In particular, both INNER
7609          and OUTER types have zero in common.  */
7610       || (oprec > iprec && TYPE_UNSIGNED (inner)))
7611     lo = hi = 0;
7612   else
7613     {
7614       /* If we are widening a signed type to another signed type, we
7615          want to obtain -2^^(iprec-1).  If we are keeping the
7616          precision or narrowing to a signed type, we want to obtain
7617          -2^(oprec-1).  */
7618       unsigned prec = oprec > iprec ? iprec : oprec;
7619
7620       if (prec <= HOST_BITS_PER_WIDE_INT)
7621         {
7622           hi = ~(unsigned HOST_WIDE_INT) 0;
7623           lo = (~(unsigned HOST_WIDE_INT) 0) << (prec - 1);
7624         }
7625       else
7626         {
7627           hi = ((~(unsigned HOST_WIDE_INT) 0)
7628                 << (prec - HOST_BITS_PER_WIDE_INT - 1));
7629           lo = 0;
7630         }
7631     }
7632
7633   return build_int_cst_wide (outer, lo, hi);
7634 }
7635
7636 /* Return nonzero if two operands that are suitable for PHI nodes are
7637    necessarily equal.  Specifically, both ARG0 and ARG1 must be either
7638    SSA_NAME or invariant.  Note that this is strictly an optimization.
7639    That is, callers of this function can directly call operand_equal_p
7640    and get the same result, only slower.  */
7641
7642 int
7643 operand_equal_for_phi_arg_p (tree arg0, tree arg1)
7644 {
7645   if (arg0 == arg1)
7646     return 1;
7647   if (TREE_CODE (arg0) == SSA_NAME || TREE_CODE (arg1) == SSA_NAME)
7648     return 0;
7649   return operand_equal_p (arg0, arg1, 0);
7650 }
7651
7652 /* Returns number of zeros at the end of binary representation of X.
7653
7654    ??? Use ffs if available?  */
7655
7656 tree
7657 num_ending_zeros (tree x)
7658 {
7659   unsigned HOST_WIDE_INT fr, nfr;
7660   unsigned num, abits;
7661   tree type = TREE_TYPE (x);
7662
7663   if (TREE_INT_CST_LOW (x) == 0)
7664     {
7665       num = HOST_BITS_PER_WIDE_INT;
7666       fr = TREE_INT_CST_HIGH (x);
7667     }
7668   else
7669     {
7670       num = 0;
7671       fr = TREE_INT_CST_LOW (x);
7672     }
7673
7674   for (abits = HOST_BITS_PER_WIDE_INT / 2; abits; abits /= 2)
7675     {
7676       nfr = fr >> abits;
7677       if (nfr << abits == fr)
7678         {
7679           num += abits;
7680           fr = nfr;
7681         }
7682     }
7683
7684   if (num > TYPE_PRECISION (type))
7685     num = TYPE_PRECISION (type);
7686
7687   return build_int_cst_type (type, num);
7688 }
7689
7690
7691 #define WALK_SUBTREE(NODE)                              \
7692   do                                                    \
7693     {                                                   \
7694       result = walk_tree (&(NODE), func, data, pset);   \
7695       if (result)                                       \
7696         return result;                                  \
7697     }                                                   \
7698   while (0)
7699
7700 /* This is a subroutine of walk_tree that walks field of TYPE that are to
7701    be walked whenever a type is seen in the tree.  Rest of operands and return
7702    value are as for walk_tree.  */
7703
7704 static tree
7705 walk_type_fields (tree type, walk_tree_fn func, void *data,
7706                   struct pointer_set_t *pset)
7707 {
7708   tree result = NULL_TREE;
7709
7710   switch (TREE_CODE (type))
7711     {
7712     case POINTER_TYPE:
7713     case REFERENCE_TYPE:
7714       /* We have to worry about mutually recursive pointers.  These can't
7715          be written in C.  They can in Ada.  It's pathological, but
7716          there's an ACATS test (c38102a) that checks it.  Deal with this
7717          by checking if we're pointing to another pointer, that one
7718          points to another pointer, that one does too, and we have no htab.
7719          If so, get a hash table.  We check three levels deep to avoid
7720          the cost of the hash table if we don't need one.  */
7721       if (POINTER_TYPE_P (TREE_TYPE (type))
7722           && POINTER_TYPE_P (TREE_TYPE (TREE_TYPE (type)))
7723           && POINTER_TYPE_P (TREE_TYPE (TREE_TYPE (TREE_TYPE (type))))
7724           && !pset)
7725         {
7726           result = walk_tree_without_duplicates (&TREE_TYPE (type),
7727                                                  func, data);
7728           if (result)
7729             return result;
7730
7731           break;
7732         }
7733
7734       /* ... fall through ... */
7735
7736     case COMPLEX_TYPE:
7737       WALK_SUBTREE (TREE_TYPE (type));
7738       break;
7739
7740     case METHOD_TYPE:
7741       WALK_SUBTREE (TYPE_METHOD_BASETYPE (type));
7742
7743       /* Fall through.  */
7744
7745     case FUNCTION_TYPE:
7746       WALK_SUBTREE (TREE_TYPE (type));
7747       {
7748         tree arg;
7749
7750         /* We never want to walk into default arguments.  */
7751         for (arg = TYPE_ARG_TYPES (type); arg; arg = TREE_CHAIN (arg))
7752           WALK_SUBTREE (TREE_VALUE (arg));
7753       }
7754       break;
7755
7756     case ARRAY_TYPE:
7757       /* Don't follow this nodes's type if a pointer for fear that we'll
7758          have infinite recursion.  Those types are uninteresting anyway.  */
7759       if (!POINTER_TYPE_P (TREE_TYPE (type))
7760           && TREE_CODE (TREE_TYPE (type)) != OFFSET_TYPE)
7761         WALK_SUBTREE (TREE_TYPE (type));
7762       WALK_SUBTREE (TYPE_DOMAIN (type));
7763       break;
7764
7765     case OFFSET_TYPE:
7766       WALK_SUBTREE (TREE_TYPE (type));
7767       WALK_SUBTREE (TYPE_OFFSET_BASETYPE (type));
7768       break;
7769
7770     default:
7771       break;
7772     }
7773
7774   return NULL_TREE;
7775 }
7776
7777 /* Apply FUNC to all the sub-trees of TP in a pre-order traversal.  FUNC is
7778    called with the DATA and the address of each sub-tree.  If FUNC returns a
7779    non-NULL value, the traversal is stopped, and the value returned by FUNC
7780    is returned.  If PSET is non-NULL it is used to record the nodes visited,
7781    and to avoid visiting a node more than once.  */
7782
7783 tree
7784 walk_tree (tree *tp, walk_tree_fn func, void *data, struct pointer_set_t *pset)
7785 {
7786   enum tree_code code;
7787   int walk_subtrees;
7788   tree result;
7789
7790 #define WALK_SUBTREE_TAIL(NODE)                         \
7791   do                                                    \
7792     {                                                   \
7793        tp = & (NODE);                                   \
7794        goto tail_recurse;                               \
7795     }                                                   \
7796   while (0)
7797
7798  tail_recurse:
7799   /* Skip empty subtrees.  */
7800   if (!*tp)
7801     return NULL_TREE;
7802
7803   /* Don't walk the same tree twice, if the user has requested
7804      that we avoid doing so.  */
7805   if (pset && pointer_set_insert (pset, *tp))
7806     return NULL_TREE;
7807
7808   /* Call the function.  */
7809   walk_subtrees = 1;
7810   result = (*func) (tp, &walk_subtrees, data);
7811
7812   /* If we found something, return it.  */
7813   if (result)
7814     return result;
7815
7816   code = TREE_CODE (*tp);
7817
7818   /* Even if we didn't, FUNC may have decided that there was nothing
7819      interesting below this point in the tree.  */
7820   if (!walk_subtrees)
7821     {
7822       /* But we still need to check our siblings.  */
7823       if (code == TREE_LIST)
7824         WALK_SUBTREE_TAIL (TREE_CHAIN (*tp));
7825       else if (code == OMP_CLAUSE)
7826         WALK_SUBTREE_TAIL (OMP_CLAUSE_CHAIN (*tp));
7827       else
7828         return NULL_TREE;
7829     }
7830
7831   result = lang_hooks.tree_inlining.walk_subtrees (tp, &walk_subtrees, func,
7832                                                    data, pset);
7833   if (result || !walk_subtrees)
7834     return result;
7835
7836   switch (code)
7837     {
7838     case ERROR_MARK:
7839     case IDENTIFIER_NODE:
7840     case INTEGER_CST:
7841     case REAL_CST:
7842     case VECTOR_CST:
7843     case STRING_CST:
7844     case BLOCK:
7845     case PLACEHOLDER_EXPR:
7846     case SSA_NAME:
7847     case FIELD_DECL:
7848     case RESULT_DECL:
7849       /* None of these have subtrees other than those already walked
7850          above.  */
7851       break;
7852
7853     case TREE_LIST:
7854       WALK_SUBTREE (TREE_VALUE (*tp));
7855       WALK_SUBTREE_TAIL (TREE_CHAIN (*tp));
7856       break;
7857
7858     case TREE_VEC:
7859       {
7860         int len = TREE_VEC_LENGTH (*tp);
7861
7862         if (len == 0)
7863           break;
7864
7865         /* Walk all elements but the first.  */
7866         while (--len)
7867           WALK_SUBTREE (TREE_VEC_ELT (*tp, len));
7868
7869         /* Now walk the first one as a tail call.  */
7870         WALK_SUBTREE_TAIL (TREE_VEC_ELT (*tp, 0));
7871       }
7872
7873     case COMPLEX_CST:
7874       WALK_SUBTREE (TREE_REALPART (*tp));
7875       WALK_SUBTREE_TAIL (TREE_IMAGPART (*tp));
7876
7877     case CONSTRUCTOR:
7878       {
7879         unsigned HOST_WIDE_INT idx;
7880         constructor_elt *ce;
7881
7882         for (idx = 0;
7883              VEC_iterate(constructor_elt, CONSTRUCTOR_ELTS (*tp), idx, ce);
7884              idx++)
7885           WALK_SUBTREE (ce->value);
7886       }
7887       break;
7888
7889     case SAVE_EXPR:
7890       WALK_SUBTREE_TAIL (TREE_OPERAND (*tp, 0));
7891
7892     case BIND_EXPR:
7893       {
7894         tree decl;
7895         for (decl = BIND_EXPR_VARS (*tp); decl; decl = TREE_CHAIN (decl))
7896           {
7897             /* Walk the DECL_INITIAL and DECL_SIZE.  We don't want to walk
7898                into declarations that are just mentioned, rather than
7899                declared; they don't really belong to this part of the tree.
7900                And, we can see cycles: the initializer for a declaration
7901                can refer to the declaration itself.  */
7902             WALK_SUBTREE (DECL_INITIAL (decl));
7903             WALK_SUBTREE (DECL_SIZE (decl));
7904             WALK_SUBTREE (DECL_SIZE_UNIT (decl));
7905           }
7906         WALK_SUBTREE_TAIL (BIND_EXPR_BODY (*tp));
7907       }
7908
7909     case STATEMENT_LIST:
7910       {
7911         tree_stmt_iterator i;
7912         for (i = tsi_start (*tp); !tsi_end_p (i); tsi_next (&i))
7913           WALK_SUBTREE (*tsi_stmt_ptr (i));
7914       }
7915       break;
7916
7917     case OMP_CLAUSE:
7918       switch (OMP_CLAUSE_CODE (*tp))
7919         {
7920         case OMP_CLAUSE_PRIVATE:
7921         case OMP_CLAUSE_SHARED:
7922         case OMP_CLAUSE_FIRSTPRIVATE:
7923         case OMP_CLAUSE_LASTPRIVATE:
7924         case OMP_CLAUSE_COPYIN:
7925         case OMP_CLAUSE_COPYPRIVATE:
7926         case OMP_CLAUSE_IF:
7927         case OMP_CLAUSE_NUM_THREADS:
7928         case OMP_CLAUSE_SCHEDULE:
7929           WALK_SUBTREE (OMP_CLAUSE_OPERAND (*tp, 0));
7930           /* FALLTHRU */
7931
7932         case OMP_CLAUSE_NOWAIT:
7933         case OMP_CLAUSE_ORDERED:
7934         case OMP_CLAUSE_DEFAULT:
7935           WALK_SUBTREE_TAIL (OMP_CLAUSE_CHAIN (*tp));
7936
7937         case OMP_CLAUSE_REDUCTION:
7938           {
7939             int i;
7940             for (i = 0; i < 4; i++)
7941               WALK_SUBTREE (OMP_CLAUSE_OPERAND (*tp, i));
7942             WALK_SUBTREE_TAIL (OMP_CLAUSE_CHAIN (*tp));
7943           }
7944
7945         default:
7946           gcc_unreachable ();
7947         }
7948       break;
7949
7950     case TARGET_EXPR:
7951       {
7952         int i, len;
7953
7954         /* TARGET_EXPRs are peculiar: operands 1 and 3 can be the same.
7955            But, we only want to walk once.  */
7956         len = (TREE_OPERAND (*tp, 3) == TREE_OPERAND (*tp, 1)) ? 2 : 3;
7957         for (i = 0; i < len; ++i)
7958           WALK_SUBTREE (TREE_OPERAND (*tp, i));
7959         WALK_SUBTREE_TAIL (TREE_OPERAND (*tp, len));
7960       }
7961
7962     case DECL_EXPR:
7963       /* If this is a TYPE_DECL, walk into the fields of the type that it's
7964          defining.  We only want to walk into these fields of a type in this
7965          case and not in the general case of a mere reference to the type.
7966
7967          The criterion is as follows: if the field can be an expression, it
7968          must be walked only here.  This should be in keeping with the fields
7969          that are directly gimplified in gimplify_type_sizes in order for the
7970          mark/copy-if-shared/unmark machinery of the gimplifier to work with
7971          variable-sized types.
7972
7973          Note that DECLs get walked as part of processing the BIND_EXPR.  */
7974       if (TREE_CODE (DECL_EXPR_DECL (*tp)) == TYPE_DECL)
7975         {
7976           tree *type_p = &TREE_TYPE (DECL_EXPR_DECL (*tp));
7977           if (TREE_CODE (*type_p) == ERROR_MARK)
7978             return NULL_TREE;
7979
7980           /* Call the function for the type.  See if it returns anything or
7981              doesn't want us to continue.  If we are to continue, walk both
7982              the normal fields and those for the declaration case.  */
7983           result = (*func) (type_p, &walk_subtrees, data);
7984           if (result || !walk_subtrees)
7985             return result;
7986
7987           result = walk_type_fields (*type_p, func, data, pset);
7988           if (result)
7989             return result;
7990
7991           /* If this is a record type, also walk the fields.  */
7992           if (TREE_CODE (*type_p) == RECORD_TYPE
7993               || TREE_CODE (*type_p) == UNION_TYPE
7994               || TREE_CODE (*type_p) == QUAL_UNION_TYPE)
7995             {
7996               tree field;
7997
7998               for (field = TYPE_FIELDS (*type_p); field;
7999                    field = TREE_CHAIN (field))
8000                 {
8001                   /* We'd like to look at the type of the field, but we can
8002                      easily get infinite recursion.  So assume it's pointed
8003                      to elsewhere in the tree.  Also, ignore things that
8004                      aren't fields.  */
8005                   if (TREE_CODE (field) != FIELD_DECL)
8006                     continue;
8007
8008                   WALK_SUBTREE (DECL_FIELD_OFFSET (field));
8009                   WALK_SUBTREE (DECL_SIZE (field));
8010                   WALK_SUBTREE (DECL_SIZE_UNIT (field));
8011                   if (TREE_CODE (*type_p) == QUAL_UNION_TYPE)
8012                     WALK_SUBTREE (DECL_QUALIFIER (field));
8013                 }
8014             }
8015
8016           /* Same for scalar types.  */
8017           else if (TREE_CODE (*type_p) == BOOLEAN_TYPE
8018                    || TREE_CODE (*type_p) == ENUMERAL_TYPE
8019                    || TREE_CODE (*type_p) == INTEGER_TYPE
8020                    || TREE_CODE (*type_p) == REAL_TYPE)
8021             {
8022               WALK_SUBTREE (TYPE_MIN_VALUE (*type_p));
8023               WALK_SUBTREE (TYPE_MAX_VALUE (*type_p));
8024             }
8025
8026           WALK_SUBTREE (TYPE_SIZE (*type_p));
8027           WALK_SUBTREE_TAIL (TYPE_SIZE_UNIT (*type_p));
8028         }
8029       /* FALLTHRU */
8030
8031     default:
8032       if (IS_EXPR_CODE_CLASS (TREE_CODE_CLASS (code))
8033           || IS_GIMPLE_STMT_CODE_CLASS (TREE_CODE_CLASS (code)))
8034         {
8035           int i, len;
8036
8037           /* Walk over all the sub-trees of this operand.  */
8038           len = TREE_CODE_LENGTH (code);
8039
8040           /* Go through the subtrees.  We need to do this in forward order so
8041              that the scope of a FOR_EXPR is handled properly.  */
8042           if (len)
8043             {
8044               for (i = 0; i < len - 1; ++i)
8045                 WALK_SUBTREE (GENERIC_TREE_OPERAND (*tp, i));
8046               WALK_SUBTREE_TAIL (GENERIC_TREE_OPERAND (*tp, len - 1));
8047             }
8048         }
8049       /* If this is a type, walk the needed fields in the type.  */
8050       else if (TYPE_P (*tp))
8051         return walk_type_fields (*tp, func, data, pset);
8052       break;
8053     }
8054
8055   /* We didn't find what we were looking for.  */
8056   return NULL_TREE;
8057
8058 #undef WALK_SUBTREE_TAIL
8059 }
8060 #undef WALK_SUBTREE
8061
8062 /* Like walk_tree, but does not walk duplicate nodes more than once.  */
8063
8064 tree
8065 walk_tree_without_duplicates (tree *tp, walk_tree_fn func, void *data)
8066 {
8067   tree result;
8068   struct pointer_set_t *pset;
8069
8070   pset = pointer_set_create ();
8071   result = walk_tree (tp, func, data, pset);
8072   pointer_set_destroy (pset);
8073   return result;
8074 }
8075
8076
8077 /* Return true if STMT is an empty statement or contains nothing but
8078    empty statements.  */
8079
8080 bool
8081 empty_body_p (tree stmt)
8082 {
8083   tree_stmt_iterator i;
8084   tree body;
8085
8086   if (IS_EMPTY_STMT (stmt))
8087     return true;
8088   else if (TREE_CODE (stmt) == BIND_EXPR)
8089     body = BIND_EXPR_BODY (stmt);
8090   else if (TREE_CODE (stmt) == STATEMENT_LIST)
8091     body = stmt;
8092   else
8093     return false;
8094
8095   for (i = tsi_start (body); !tsi_end_p (i); tsi_next (&i))
8096     if (!empty_body_p (tsi_stmt (i)))
8097       return false;
8098
8099   return true;
8100 }
8101
8102 tree *
8103 tree_block (tree t)
8104 {
8105   char const c = TREE_CODE_CLASS (TREE_CODE (t));
8106
8107   if (IS_EXPR_CODE_CLASS (c))
8108     return &t->exp.block;
8109   else if (IS_GIMPLE_STMT_CODE_CLASS (c))
8110     return &GIMPLE_STMT_BLOCK (t);
8111   gcc_unreachable ();
8112   return NULL;
8113 }
8114
8115 tree *
8116 generic_tree_operand (tree node, int i)
8117 {
8118   if (GIMPLE_STMT_P (node))
8119     return &GIMPLE_STMT_OPERAND (node, i);
8120   return &TREE_OPERAND (node, i);
8121 }
8122
8123 tree *
8124 generic_tree_type (tree node)
8125 {
8126   if (GIMPLE_STMT_P (node))
8127     return &void_type_node;
8128   return &TREE_TYPE (node);
8129 }
8130
8131 #include "gt-tree.h"