gcc/c-objc-common.c

   1 /* Some code common to C and ObjC front ends.
   2    Copyright (C) 2001, 2002, 2003 Free Software Foundation, Inc.
   3
   4 This file is part of GCC.
   5
   6 GCC is free software; you can redistribute it and/or modify it under
   7 the terms of the GNU General Public License as published by the Free
   8 Software Foundation; either version 2, or (at your option) any later
   9 version.
  10
  11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14 for more details.
  15
  16 You should have received a copy of the GNU General Public License
  17 along with GCC; see the file COPYING.  If not, write to the Free
  18 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
  19 02111-1307, USA.  */
  20
  21 #include "config.h"
  22 #include "system.h"
  23 #include "coretypes.h"
  24 #include "tm.h"
  25 #include "tree.h"
  26 #include "rtl.h"
  27 #include "insn-config.h"
  28 #include "integrate.h"
  29 #include "expr.h"
  30 #include "c-tree.h"
  31 #include "function.h"
  32 #include "flags.h"
  33 #include "toplev.h"
  34 #include "diagnostic.h"
  35 #include "tree-inline.h"
  36 #include "varray.h"
  37 #include "ggc.h"
  38 #include "langhooks.h"
  39 #include "target.h"
  40 #include "cgraph.h"
  41
  42 static bool c_tree_printer (pretty_printer *, text_info *);
  43 static tree inline_forbidden_p (tree *, int *, void *);
  44 static void expand_deferred_fns (void);
  45 static tree start_cdtor (int);
  46 static void finish_cdtor (tree);
  47
  48 static GTY(()) varray_type deferred_fns;
  49
  50 int
  51 c_missing_noreturn_ok_p (tree decl)
  52 {
  53   /* A missing noreturn is not ok for freestanding implementations and
  54      ok for the `main' function in hosted implementations.  */
  55   return flag_hosted && MAIN_NAME_P (DECL_ASSEMBLER_NAME (decl));
  56 }
  57
  58 /* We want to inline `extern inline' functions even if this would
  59    violate inlining limits.  Some glibc and linux constructs depend on
  60    such functions always being inlined when optimizing.  */
  61
  62 int
  63 c_disregard_inline_limits (tree fn)
  64 {
  65   if (lookup_attribute ("always_inline", DECL_ATTRIBUTES (fn)) != NULL)
  66     return 1;
  67
  68   return DECL_DECLARED_INLINE_P (fn) && DECL_EXTERNAL (fn);
  69 }
  70
  71 static tree
  72 inline_forbidden_p (tree *nodep, int *walk_subtrees ATTRIBUTE_UNUSED,
  73                     void *fn)
  74 {
  75   tree node = *nodep;
  76   tree t;
  77
  78   switch (TREE_CODE (node))
  79     {
  80     case CALL_EXPR:
  81       t = get_callee_fndecl (node);
  82
  83       if (! t)
  84         break;
  85
  86       /* We cannot inline functions that call setjmp.  */
  87       if (setjmp_call_p (t))
  88         return node;
  89
  90       switch (DECL_FUNCTION_CODE (t))
  91         {
  92           /* We cannot inline functions that take a variable number of
  93              arguments.  */
  94         case BUILT_IN_VA_START:
  95         case BUILT_IN_STDARG_START:
  96 #if 0
  97           /* Functions that need information about the address of the
  98              caller can't (shouldn't?) be inlined.  */
  99         case BUILT_IN_RETURN_ADDRESS:
 100 #endif
 101           return node;
 102
 103         default:
 104           break;
 105         }
 106
 107       break;
 108
 109     case DECL_STMT:
 110       /* We cannot inline functions that contain other functions.  */
 111       if (TREE_CODE (TREE_OPERAND (node, 0)) == FUNCTION_DECL
 112           && DECL_INITIAL (TREE_OPERAND (node, 0)))
 113         return node;
 114       break;
 115
 116     case GOTO_STMT:
 117     case GOTO_EXPR:
 118       t = TREE_OPERAND (node, 0);
 119
 120       /* We will not inline a function which uses computed goto.  The
 121          addresses of its local labels, which may be tucked into
 122          global storage, are of course not constant across
 123          instantiations, which causes unexpected behavior.  */
 124       if (TREE_CODE (t) != LABEL_DECL)
 125         return node;
 126
 127       /* We cannot inline a nested function that jumps to a nonlocal
 128          label.  */
 129       if (TREE_CODE (t) == LABEL_DECL
 130           && !DECL_FILE_SCOPE_P (t) && DECL_CONTEXT (t) != fn)
 131         return node;
 132
 133       break;
 134
 135     case RECORD_TYPE:
 136     case UNION_TYPE:
 137       /* We cannot inline a function of the form
 138
 139            void F (int i) { struct S { int ar[i]; } s; }
 140
 141          Attempting to do so produces a catch-22 in tree-inline.c.
 142          If walk_tree examines the TYPE_FIELDS chain of RECORD_TYPE/
 143          UNION_TYPE nodes, then it goes into infinite recursion on a
 144          structure containing a pointer to its own type.  If it doesn't,
 145          then the type node for S doesn't get adjusted properly when
 146          F is inlined, and we abort in find_function_data.  */
 147       for (t = TYPE_FIELDS (node); t; t = TREE_CHAIN (t))
 148         if (variably_modified_type_p (TREE_TYPE (t)))
 149           return node;
 150
 151     default:
 152       break;
 153     }
 154
 155   return NULL_TREE;
 156 }
 157
 158 int
 159 c_cannot_inline_tree_fn (tree *fnp)
 160 {
 161   tree fn = *fnp;
 162   tree t;
 163
 164   if (flag_really_no_inline
 165       && lookup_attribute ("always_inline", DECL_ATTRIBUTES (fn)) == NULL)
 166     return 1;
 167
 168   /* Don't auto-inline anything that might not be bound within
 169      this unit of translation.  */
 170   if (!DECL_DECLARED_INLINE_P (fn) && !(*targetm.binds_local_p) (fn))
 171     goto cannot_inline;
 172
 173   if (! function_attribute_inlinable_p (fn))
 174     goto cannot_inline;
 175
 176   /* If a function has pending sizes, we must not defer its
 177      compilation, and we can't inline it as a tree.  */
 178   if (fn == current_function_decl)
 179     {
 180       t = get_pending_sizes ();
 181       put_pending_sizes (t);
 182
 183       if (t)
 184         goto cannot_inline;
 185     }
 186
 187   if (! DECL_FILE_SCOPE_P (fn))
 188     {
 189       /* If a nested function has pending sizes, we may have already
 190          saved them.  */
 191       if (DECL_LANG_SPECIFIC (fn)->pending_sizes)
 192         goto cannot_inline;
 193     }
 194   else
 195     {
 196       /* We rely on the fact that this function is called upfront,
 197          just before we start expanding a function.  If FN is active
 198          (i.e., it's the current_function_decl or a parent thereof),
 199          we have to walk FN's saved tree.  Otherwise, we can safely
 200          assume we have done it before and, if we didn't mark it as
 201          uninlinable (in which case we wouldn't have been called), it
 202          is inlinable.  Unfortunately, this strategy doesn't work for
 203          nested functions, because they're only expanded as part of
 204          their enclosing functions, so the inlinability test comes in
 205          late.  */
 206       t = current_function_decl;
 207
 208       while (t && t != fn)
 209         t = DECL_CONTEXT (t);
 210       if (! t)
 211         return 0;
 212     }
 213
 214   if (walk_tree (&DECL_SAVED_TREE (fn), inline_forbidden_p, fn, NULL))
 215     goto cannot_inline;
 216
 217   return 0;
 218
 219  cannot_inline:
 220   DECL_UNINLINABLE (fn) = 1;
 221   return 1;
 222 }
 223
 224 /* Called from check_global_declarations.  */
 225
 226 bool
 227 c_warn_unused_global_decl (tree decl)
 228 {
 229   if (TREE_CODE (decl) == FUNCTION_DECL && DECL_DECLARED_INLINE_P (decl))
 230     return false;
 231   if (DECL_IN_SYSTEM_HEADER (decl))
 232     return false;
 233
 234   return true;
 235 }
 236
 237 /* Initialization common to C and Objective-C front ends.  */
 238 bool
 239 c_objc_common_init (void)
 240 {
 241   static const enum tree_code stmt_codes[] = {
 242     c_common_stmt_codes
 243   };
 244
 245   INIT_STATEMENT_CODES (stmt_codes);
 246
 247   c_init_decl_processing ();
 248
 249   if (c_common_init () == false)
 250     return false;
 251
 252   lang_expand_decl_stmt = c_expand_decl_stmt;
 253
 254   /* These were not defined in the Objective-C front end, but I'm
 255      putting them here anyway.  The diagnostic format decoder might
 256      want an enhanced ObjC implementation.  */
 257   diagnostic_format_decoder (global_dc) = &c_tree_printer;
 258   lang_missing_noreturn_ok_p = &c_missing_noreturn_ok_p;
 259
 260   /* If still unspecified, make it match -std=c99
 261      (allowing for -pedantic-errors).  */
 262   if (mesg_implicit_function_declaration < 0)
 263     {
 264       if (flag_isoc99)
 265         mesg_implicit_function_declaration = flag_pedantic_errors ? 2 : 1;
 266       else
 267         mesg_implicit_function_declaration = 0;
 268     }
 269
 270   VARRAY_TREE_INIT (deferred_fns, 32, "deferred_fns");
 271
 272   return true;
 273 }
 274
 275 /* Register a function tree, so that its optimization and conversion
 276    to RTL is only done at the end of the compilation.  */
 277
 278 int
 279 defer_fn (tree fn)
 280 {
 281   VARRAY_PUSH_TREE (deferred_fns, fn);
 282
 283   return 1;
 284 }
 285
 286 /* Expand deferred functions for C and ObjC.  */
 287
 288 static void
 289 expand_deferred_fns (void)
 290 {
 291   unsigned int i;
 292   bool reconsider;
 293
 294   do
 295     {
 296       reconsider = false;
 297       for (i = 0; i < VARRAY_ACTIVE_SIZE (deferred_fns); i++)
 298         {
 299           tree decl = VARRAY_TREE (deferred_fns, i);
 300
 301           if (TREE_ASM_WRITTEN (decl))
 302             continue;
 303
 304           /* "extern inline" says the symbol exists externally,
 305               which means we should *never* expand it locally
 306               unless we're actually inlining it.  */
 307           /* ??? Why did we queue these in the first place?  */
 308           if (DECL_DECLARED_INLINE_P (decl) && DECL_EXTERNAL (decl))
 309             continue;
 310
 311           /* With flag_keep_inline_functions, we're emitting everything,
 312              so we never need to reconsider.  */
 313           if (flag_keep_inline_functions)
 314             ;
 315           /* Must emit all public functions.  C doesn't have COMDAT
 316              functions, so we don't need to check that, like C++.  */
 317           else if (TREE_PUBLIC (decl))
 318             reconsider = true;
 319           /* Must emit if the symbol is referenced.  */
 320           else if (TREE_SYMBOL_REFERENCED (DECL_ASSEMBLER_NAME (decl)))
 321             reconsider = true;
 322           else
 323             continue;
 324
 325           c_expand_deferred_function (decl);
 326         }
 327     }
 328   while (reconsider);
 329
 330   deferred_fns = 0;
 331 }
 332
 333 static tree
 334 start_cdtor (int method_type)
 335 {
 336   tree fnname = get_file_function_name (method_type);
 337   tree void_list_node_1 = build_tree_list (NULL_TREE, void_type_node);
 338   tree body;
 339
 340   start_function (void_list_node_1,
 341                   build_nt (CALL_EXPR, fnname,
 342                             tree_cons (NULL_TREE, NULL_TREE, void_list_node_1),
 343                             NULL_TREE),
 344                   NULL_TREE);
 345   store_parm_decls ();
 346
 347   current_function_cannot_inline
 348     = "static constructors and destructors cannot be inlined";
 349
 350   body = c_begin_compound_stmt ();
 351
 352   pushlevel (0);
 353   clear_last_expr ();
 354   add_scope_stmt (/*begin_p=*/1, /*partial_p=*/0);
 355
 356   return body;
 357 }
 358
 359 static void
 360 finish_cdtor (tree body)
 361 {
 362   tree scope;
 363   tree block;
 364
 365   scope = add_scope_stmt (/*begin_p=*/0, /*partial_p=*/0);
 366   block = poplevel (0, 0, 0);
 367   SCOPE_STMT_BLOCK (TREE_PURPOSE (scope)) = block;
 368   SCOPE_STMT_BLOCK (TREE_VALUE (scope)) = block;
 369
 370   RECHAIN_STMTS (body, COMPOUND_BODY (body));
 371
 372   finish_function (0, 0);
 373 }
 374
 375 /* Called at end of parsing, but before end-of-file processing.  */
 376
 377 void
 378 c_objc_common_finish_file (void)
 379 {
 380   if (pch_file)
 381     c_common_write_pch ();
 382
 383   /* If multiple translation units were built, copy information between
 384      them based on linkage rules.  */
 385   merge_translation_unit_decls ();
 386
 387   if (flag_unit_at_a_time)
 388     {
 389       cgraph_finalize_compilation_unit ();
 390       cgraph_optimize ();
 391     }
 392   else
 393     expand_deferred_fns ();
 394
 395   if (static_ctors)
 396     {
 397       tree body = start_cdtor ('I');
 398
 399       for (; static_ctors; static_ctors = TREE_CHAIN (static_ctors))
 400         c_expand_expr_stmt (build_function_call (TREE_VALUE (static_ctors),
 401                                                  NULL_TREE));
 402
 403       finish_cdtor (body);
 404     }
 405
 406   if (static_dtors)
 407     {
 408       tree body = start_cdtor ('D');
 409
 410       for (; static_dtors; static_dtors = TREE_CHAIN (static_dtors))
 411         c_expand_expr_stmt (build_function_call (TREE_VALUE (static_dtors),
 412                                                  NULL_TREE));
 413
 414       finish_cdtor (body);
 415     }
 416
 417   {
 418     int flags;
 419     FILE *stream = dump_begin (TDI_all, &flags);
 420
 421     if (stream)
 422       {
 423         dump_node (getdecls (), flags & ~TDF_SLIM, stream);
 424         dump_end (TDI_all, stream);
 425       }
 426   }
 427 }
 428
 429 /* Called during diagnostic message formatting process to print a
 430    source-level entity onto BUFFER.  The meaning of the format specifiers
 431    is as follows:
 432    %D: a general decl,
 433    %E: An expression,
 434    %F: a function declaration,
 435    %T: a type.
 436
 437    These format specifiers form a subset of the format specifiers set used
 438    by the C++ front-end.
 439    Please notice when called, the `%' part was already skipped by the
 440    diagnostic machinery.  */
 441 static bool
 442 c_tree_printer (pretty_printer *pp, text_info *text)
 443 {
 444   tree t = va_arg (*text->args_ptr, tree);
 445
 446   switch (*text->format_spec)
 447     {
 448     case 'D':
 449     case 'F':
 450     case 'T':
 451       {
 452         const char *n = DECL_NAME (t)
 453           ? (*lang_hooks.decl_printable_name) (t, 2)
 454           : "({anonymous})";
 455         pp_string (pp, n);
 456       }
 457       return true;
 458
 459     case 'E':
 460        if (TREE_CODE (t) == IDENTIFIER_NODE)
 461          {
 462            pp_string (pp, IDENTIFIER_POINTER (t));
 463            return true;
 464          }
 465        return false;
 466
 467     default:
 468       return false;
 469     }
 470 }
 471
 472 #include "gt-c-objc-common.h"