gcc/ipa-prop.h

   1 /* Interprocedural analyses.
   2    Copyright (C) 2005, 2007, 2008, 2009, 2010
   3    Free Software Foundation, Inc.
   4
   5 This file is part of GCC.
   6
   7 GCC is free software; you can redistribute it and/or modify it under
   8 the terms of the GNU General Public License as published by the Free
   9 Software Foundation; either version 3, or (at your option) any later
  10 version.
  11
  12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
  13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15 for more details.
  16
  17 You should have received a copy of the GNU General Public License
  18 along with GCC; see the file COPYING3.  If not see
  19 <http://www.gnu.org/licenses/>.  */
  20
  21 #ifndef IPA_PROP_H
  22 #define IPA_PROP_H
  23
  24 #include "tree.h"
  25 #include "vec.h"
  26 #include "cgraph.h"
  27 #include "gimple.h"
  28 #include "alloc-pool.h"
  29
  30 /* The following definitions and interfaces are used by
  31    interprocedural analyses or parameters.  */
  32
  33 /* ipa-prop.c stuff (ipa-cp, indirect inlining):  */
  34
  35 /* A jump function for a callsite represents the values passed as actual
  36    arguments of the callsite.  They were originally proposed in a paper called
  37    "Interprocedural Constant Propagation", by David Callahan, Keith D Cooper,
  38    Ken Kennedy, Linda Torczon in Comp86, pg 152-161.  There are three main
  39    types of values :
  40
  41    Pass-through - the caller's formal parameter is passed as an actual
  42                   argument, possibly one simple operation performed on it.
  43    Constant     - a constant (is_gimple_ip_invariant)is passed as an actual
  44                   argument.
  45    Unknown      - neither of the above.
  46
  47    IPA_JF_CONST_MEMBER_PTR stands for C++ member pointers, it is a special
  48    constant in this regard because it is in fact a structure consisting of two
  49    values.  Other constants are represented with IPA_JF_CONST.
  50
  51    IPA_JF_ANCESTOR is a special pass-through jump function, which means that
  52    the result is an address of a part of the object pointed to by the formal
  53    parameter to which the function refers.  It is mainly intended to represent
  54    getting addresses of of ancestor fields in C++
  55    (e.g. &this_1(D)->D.1766.D.1756).  Note that if the original pointer is
  56    NULL, ancestor jump function must behave like a simple pass-through.
  57
  58    Other pass-through functions can either simply pass on an unchanged formal
  59    parameter or can apply one simple binary operation to it (such jump
  60    functions are called polynomial).
  61
  62    IPA_JF_KNOWN_TYPE is a special type of an "unknown" function that applies
  63    only to pointer parameters.  It means that even though we cannot prove that
  64    the passed value is an interprocedural constant, we still know the exact
  65    type of the containing object which may be valuable for devirtualization.
  66
  67    Jump functions are computed in ipa-prop.c by function
  68    update_call_notes_after_inlining.  Some information can be lost and jump
  69    functions degraded accordingly when inlining, see
  70    update_call_notes_after_inlining in the same file.  */
  71
  72 enum jump_func_type
  73 {
  74   IPA_JF_UNKNOWN = 0,  /* newly allocated and zeroed jump functions default */
  75   IPA_JF_KNOWN_TYPE,        /* represented by field known_type */
  76   IPA_JF_CONST,             /* represented by field costant */
  77   IPA_JF_CONST_MEMBER_PTR,  /* represented by field member_cst */
  78   IPA_JF_PASS_THROUGH,      /* represented by field pass_through */
  79   IPA_JF_ANCESTOR           /* represented by field ancestor */
  80 };
  81
  82 /* Structure holding data required to describe a known type jump function.  */
  83 struct GTY(()) ipa_known_type_data
  84 {
  85   /* Offset of the component of the base_type being described.  */
  86   HOST_WIDE_INT offset;
  87   /* Type of the whole object.  */
  88   tree base_type;
  89   /* Type of the component of the object that is being described.  */
  90   tree component_type;
  91 };
  92
  93 /* Structure holding data required to describe a pass-through jump function.  */
  94
  95 struct GTY(()) ipa_pass_through_data
  96 {
  97   /* If an operation is to be performed on the original parameter, this is the
  98      second (constant) operand.  */
  99   tree operand;
 100   /* Number of the caller's formal parameter being passed.  */
 101   int formal_id;
 102   /* Operation that is performed on the argument before it is passed on.
 103      NOP_EXPR means no operation.  Otherwise oper must be a simple binary
 104      arithmetic operation where the caller's parameter is the first operand and
 105      operand field from this structure is the second one.  */
 106   enum tree_code operation;
 107 };
 108
 109 /* Structure holding data required to describe an ancestor pass-through
 110    jump function.  */
 111
 112 struct GTY(()) ipa_ancestor_jf_data
 113 {
 114   /* Offset of the field representing the ancestor.  */
 115   HOST_WIDE_INT offset;
 116   /* Type of the result.  */
 117   tree type;
 118   /* Number of the caller's formal parameter being passed.  */
 119   int formal_id;
 120 };
 121
 122 /* Structure holding a C++ member pointer constant.  Holds a pointer to the
 123    method and delta offset.  */
 124 struct GTY(()) ipa_member_ptr_cst
 125 {
 126   tree pfn;
 127   tree delta;
 128 };
 129
 130 /* A jump function for a callsite represents the values passed as actual
 131    arguments of the callsite. See enum jump_func_type for the various
 132    types of jump functions supported.  */
 133 typedef struct GTY (()) ipa_jump_func
 134 {
 135   enum jump_func_type type;
 136   /* Represents a value of a jump function.  pass_through is used only in jump
 137      function context.  constant represents the actual constant in constant jump
 138      functions and member_cst holds constant c++ member functions.  */
 139   union jump_func_value
 140   {
 141     struct ipa_known_type_data GTY ((tag ("IPA_JF_KNOWN_TYPE"))) known_type;
 142     tree GTY ((tag ("IPA_JF_CONST"))) constant;
 143     struct ipa_member_ptr_cst GTY ((tag ("IPA_JF_CONST_MEMBER_PTR"))) member_cst;
 144     struct ipa_pass_through_data GTY ((tag ("IPA_JF_PASS_THROUGH"))) pass_through;
 145     struct ipa_ancestor_jf_data GTY ((tag ("IPA_JF_ANCESTOR"))) ancestor;
 146   } GTY ((desc ("%1.type"))) value;
 147 } ipa_jump_func_t;
 148
 149 DEF_VEC_O (ipa_jump_func_t);
 150 DEF_VEC_ALLOC_O (ipa_jump_func_t, gc);
 151
 152 /* Return the offset of the component that is decribed by a known type jump
 153    function JFUNC.  */
 154
 155 static inline HOST_WIDE_INT
 156 ipa_get_jf_known_type_offset (struct ipa_jump_func *jfunc)
 157 {
 158   gcc_checking_assert (jfunc->type == IPA_JF_KNOWN_TYPE);
 159   return jfunc->value.known_type.offset;
 160 }
 161
 162 /* Return the base type of a known type jump function JFUNC.  */
 163
 164 static inline tree
 165 ipa_get_jf_known_type_base_type (struct ipa_jump_func *jfunc)
 166 {
 167   gcc_checking_assert (jfunc->type == IPA_JF_KNOWN_TYPE);
 168   return jfunc->value.known_type.base_type;
 169 }
 170
 171 /* Return the component type of a known type jump function JFUNC.  */
 172
 173 static inline tree
 174 ipa_get_jf_known_type_component_type (struct ipa_jump_func *jfunc)
 175 {
 176   gcc_checking_assert (jfunc->type == IPA_JF_KNOWN_TYPE);
 177   return jfunc->value.known_type.component_type;
 178 }
 179
 180 /* Return the constant stored in a constant jump functin JFUNC.  */
 181
 182 static inline tree
 183 ipa_get_jf_constant (struct ipa_jump_func *jfunc)
 184 {
 185   gcc_checking_assert (jfunc->type == IPA_JF_CONST);
 186   return jfunc->value.constant;
 187 }
 188
 189 /* Return the operand of a pass through jmp function JFUNC.  */
 190
 191 static inline tree
 192 ipa_get_jf_pass_through_operand (struct ipa_jump_func *jfunc)
 193 {
 194   gcc_checking_assert (jfunc->type == IPA_JF_PASS_THROUGH);
 195   return jfunc->value.pass_through.operand;
 196 }
 197
 198 /* Return the number of the caller's formal parameter that a pass through jump
 199    function JFUNC refers to.  */
 200
 201 static inline int
 202 ipa_get_jf_pass_through_formal_id (struct ipa_jump_func *jfunc)
 203 {
 204   gcc_checking_assert (jfunc->type == IPA_JF_PASS_THROUGH);
 205   return jfunc->value.pass_through.formal_id;
 206 }
 207
 208 /* Return operation of a pass through jump function JFUNC.  */
 209
 210 static inline enum tree_code
 211 ipa_get_jf_pass_through_operation (struct ipa_jump_func *jfunc)
 212 {
 213   gcc_checking_assert (jfunc->type == IPA_JF_PASS_THROUGH);
 214   return jfunc->value.pass_through.operation;
 215 }
 216
 217 /* Return the offset of an ancestor jump function JFUNC.  */
 218
 219 static inline HOST_WIDE_INT
 220 ipa_get_jf_ancestor_offset (struct ipa_jump_func *jfunc)
 221 {
 222   gcc_checking_assert (jfunc->type == IPA_JF_ANCESTOR);
 223   return jfunc->value.ancestor.offset;
 224 }
 225
 226 /* Return the result type of an ancestor jump function JFUNC.  */
 227
 228 static inline tree
 229 ipa_get_jf_ancestor_type (struct ipa_jump_func *jfunc)
 230 {
 231   gcc_checking_assert (jfunc->type == IPA_JF_ANCESTOR);
 232   return jfunc->value.ancestor.type;
 233 }
 234
 235 /* Return the number of the caller's formal parameter that an ancestor jump
 236    function JFUNC refers to.  */
 237
 238 static inline int
 239 ipa_get_jf_ancestor_formal_id (struct ipa_jump_func *jfunc)
 240 {
 241   gcc_checking_assert (jfunc->type == IPA_JF_ANCESTOR);
 242   return jfunc->value.ancestor.formal_id;
 243 }
 244
 245 /* Return the pfn part of a member pointer constant jump function JFUNC.  */
 246
 247 static inline tree
 248 ipa_get_jf_member_ptr_pfn (struct ipa_jump_func *jfunc)
 249 {
 250   gcc_checking_assert (jfunc->type == IPA_JF_CONST_MEMBER_PTR);
 251   return jfunc->value.member_cst.pfn;
 252 }
 253
 254 /* Summary describing a single formal parameter.  */
 255
 256 struct ipa_param_descriptor
 257 {
 258   /* PARAM_DECL of this parameter.  */
 259   tree decl;
 260   /* The parameter is used.  */
 261   unsigned used : 1;
 262 };
 263
 264 typedef struct ipa_param_descriptor ipa_param_descriptor_t;
 265 DEF_VEC_O (ipa_param_descriptor_t);
 266 DEF_VEC_ALLOC_O (ipa_param_descriptor_t, heap);
 267 struct ipcp_lattice;
 268
 269 /* ipa_node_params stores information related to formal parameters of functions
 270    and some other information for interprocedural passes that operate on
 271    parameters (such as ipa-cp).  */
 272
 273 struct ipa_node_params
 274 {
 275   /* Information about individual formal parameters that are gathered when
 276      summaries are generated. */
 277   VEC (ipa_param_descriptor_t, heap) *descriptors;
 278   /* Pointer to an array of structures describing individual formal
 279      parameters.  */
 280   struct ipcp_lattice *lattices;
 281   /* Only for versioned nodes this field would not be NULL,
 282      it points to the node that IPA cp cloned from.  */
 283   struct cgraph_node *ipcp_orig_node;
 284   /* If this node is an ipa-cp clone, these are the known values that describe
 285      what it has been specialized for.  */
 286   VEC (tree, heap) *known_vals;
 287   /* Whether the param uses analysis has already been performed.  */
 288   unsigned uses_analysis_done : 1;
 289   /* Whether the function is enqueued in ipa-cp propagation stack.  */
 290   unsigned node_enqueued : 1;
 291   /* Whether we should create a specialized version based on values that are
 292      known to be constant in all contexts.  */
 293   unsigned clone_for_all_contexts : 1;
 294   /* Node has been completely replaced by clones and will be removed after
 295      ipa-cp is finished.  */
 296   unsigned node_dead : 1;
 297 };
 298
 299 /* ipa_node_params access functions.  Please use these to access fields that
 300    are or will be shared among various passes.  */
 301
 302 /* Return the number of formal parameters. */
 303
 304 static inline int
 305 ipa_get_param_count (struct ipa_node_params *info)
 306 {
 307   return VEC_length (ipa_param_descriptor_t, info->descriptors);
 308 }
 309
 310 /* Return the declaration of Ith formal parameter of the function corresponding
 311    to INFO.  Note there is no setter function as this array is built just once
 312    using ipa_initialize_node_params. */
 313
 314 static inline tree
 315 ipa_get_param (struct ipa_node_params *info, int i)
 316 {
 317   return VEC_index (ipa_param_descriptor_t, info->descriptors, i)->decl;
 318 }
 319
 320 /* Set the used flag corresponding to the Ith formal parameter of the function
 321    associated with INFO to VAL.  */
 322
 323 static inline void
 324 ipa_set_param_used (struct ipa_node_params *info, int i, bool val)
 325 {
 326   VEC_index (ipa_param_descriptor_t, info->descriptors, i)->used = val;
 327 }
 328
 329 /* Return the used flag corresponding to the Ith formal parameter of the
 330    function associated with INFO.  */
 331
 332 static inline bool
 333 ipa_is_param_used (struct ipa_node_params *info, int i)
 334 {
 335   return VEC_index (ipa_param_descriptor_t, info->descriptors, i)->used;
 336 }
 337
 338 /* ipa_edge_args stores information related to a callsite and particularly its
 339    arguments.  It can be accessed by the IPA_EDGE_REF macro.  */
 340 typedef struct GTY(()) ipa_edge_args
 341 {
 342   /* Vector of the callsite's jump function of each parameter.  */
 343   VEC (ipa_jump_func_t, gc) *jump_functions;
 344 } ipa_edge_args_t;
 345
 346 /* ipa_edge_args access functions.  Please use these to access fields that
 347    are or will be shared among various passes.  */
 348
 349 /* Return the number of actual arguments. */
 350
 351 static inline int
 352 ipa_get_cs_argument_count (struct ipa_edge_args *args)
 353 {
 354   return VEC_length (ipa_jump_func_t, args->jump_functions);
 355 }
 356
 357 /* Returns a pointer to the jump function for the ith argument.  Please note
 358    there is no setter function as jump functions are all set up in
 359    ipa_compute_jump_functions. */
 360
 361 static inline struct ipa_jump_func *
 362 ipa_get_ith_jump_func (struct ipa_edge_args *args, int i)
 363 {
 364   return VEC_index (ipa_jump_func_t, args->jump_functions, i);
 365 }
 366
 367 /* Vectors need to have typedefs of structures.  */
 368 typedef struct ipa_node_params ipa_node_params_t;
 369
 370 /* Types of vectors holding the infos.  */
 371 DEF_VEC_O (ipa_node_params_t);
 372 DEF_VEC_ALLOC_O (ipa_node_params_t, heap);
 373 DEF_VEC_O (ipa_edge_args_t);
 374 DEF_VEC_ALLOC_O (ipa_edge_args_t, gc);
 375
 376 /* Vector where the parameter infos are actually stored. */
 377 extern VEC (ipa_node_params_t, heap) *ipa_node_params_vector;
 378 /* Vector where the parameter infos are actually stored. */
 379 extern GTY(()) VEC (ipa_edge_args_t, gc) *ipa_edge_args_vector;
 380
 381 /* Return the associated parameter/argument info corresponding to the given
 382    node/edge.  */
 383 #define IPA_NODE_REF(NODE) (VEC_index (ipa_node_params_t, \
 384                                        ipa_node_params_vector, (NODE)->uid))
 385 #define IPA_EDGE_REF(EDGE) (VEC_index (ipa_edge_args_t, \
 386                                        ipa_edge_args_vector, (EDGE)->uid))
 387 /* This macro checks validity of index returned by
 388    ipa_get_param_decl_index function.  */
 389 #define IS_VALID_JUMP_FUNC_INDEX(I) ((I) != -1)
 390
 391 /* Creating and freeing ipa_node_params and ipa_edge_args.  */
 392 void ipa_create_all_node_params (void);
 393 void ipa_create_all_edge_args (void);
 394 void ipa_free_edge_args_substructures (struct ipa_edge_args *);
 395 void ipa_free_node_params_substructures (struct ipa_node_params *);
 396 void ipa_free_all_node_params (void);
 397 void ipa_free_all_edge_args (void);
 398 void ipa_free_all_structures_after_ipa_cp (void);
 399 void ipa_free_all_structures_after_iinln (void);
 400 void ipa_register_cgraph_hooks (void);
 401
 402 /* This function ensures the array of node param infos is big enough to
 403    accommodate a structure for all nodes and reallocates it if not.  */
 404
 405 static inline void
 406 ipa_check_create_node_params (void)
 407 {
 408   if (!ipa_node_params_vector)
 409     ipa_node_params_vector = VEC_alloc (ipa_node_params_t, heap,
 410                                         cgraph_max_uid);
 411
 412   if (VEC_length (ipa_node_params_t, ipa_node_params_vector)
 413       <= (unsigned) cgraph_max_uid)
 414     VEC_safe_grow_cleared (ipa_node_params_t, heap,
 415                            ipa_node_params_vector, cgraph_max_uid + 1);
 416 }
 417
 418 /* This function ensures the array of edge arguments infos is big enough to
 419    accommodate a structure for all edges and reallocates it if not.  */
 420
 421 static inline void
 422 ipa_check_create_edge_args (void)
 423 {
 424   if (!ipa_edge_args_vector)
 425     ipa_edge_args_vector = VEC_alloc (ipa_edge_args_t, gc,
 426                                       cgraph_edge_max_uid);
 427
 428   if (VEC_length (ipa_edge_args_t, ipa_edge_args_vector)
 429       <=  (unsigned) cgraph_edge_max_uid)
 430     VEC_safe_grow_cleared (ipa_edge_args_t, gc, ipa_edge_args_vector,
 431                            cgraph_edge_max_uid + 1);
 432 }
 433
 434 /* Returns true if the array of edge infos is large enough to accommodate an
 435    info for EDGE.  The main purpose of this function is that debug dumping
 436    function can check info availability without causing reallocations.  */
 437
 438 static inline bool
 439 ipa_edge_args_info_available_for_edge_p (struct cgraph_edge *edge)
 440 {
 441   return ((unsigned) edge->uid < VEC_length (ipa_edge_args_t,
 442                                              ipa_edge_args_vector));
 443 }
 444
 445 /* Function formal parameters related computations.  */
 446 void ipa_initialize_node_params (struct cgraph_node *node);
 447 bool ipa_propagate_indirect_call_infos (struct cgraph_edge *cs,
 448                                         VEC (cgraph_edge_p, heap) **new_edges);
 449
 450 /* Indirect edge and binfo processing.  */
 451 tree ipa_get_indirect_edge_target (struct cgraph_edge *ie,
 452                                    VEC (tree, heap) *known_csts,
 453                                    VEC (tree, heap) *known_binfs);
 454 struct cgraph_edge *ipa_make_edge_direct_to_target (struct cgraph_edge *, tree);
 455
 456 /* Functions related to both.  */
 457 void ipa_analyze_node (struct cgraph_node *);
 458
 459 /* Debugging interface.  */
 460 void ipa_print_node_params (FILE *, struct cgraph_node *node);
 461 void ipa_print_all_params (FILE *);
 462 void ipa_print_node_jump_functions (FILE *f, struct cgraph_node *node);
 463 void ipa_print_all_jump_functions (FILE * f);
 464 void ipcp_verify_propagated_values (void);
 465
 466 extern alloc_pool ipcp_values_pool;
 467 extern alloc_pool ipcp_sources_pool;
 468
 469 /* Structure to describe transformations of formal parameters and actual
 470    arguments.  Each instance describes one new parameter and they are meant to
 471    be stored in a vector.  Additionally, most users will probably want to store
 472    adjustments about parameters that are being removed altogether so that SSA
 473    names belonging to them can be replaced by SSA names of an artificial
 474    variable.  */
 475 struct ipa_parm_adjustment
 476 {
 477   /* The original PARM_DECL itself, helpful for processing of the body of the
 478      function itself.  Intended for traversing function bodies.
 479      ipa_modify_formal_parameters, ipa_modify_call_arguments and
 480      ipa_combine_adjustments ignore this and use base_index.
 481      ipa_modify_formal_parameters actually sets this.  */
 482   tree base;
 483
 484   /* Type of the new parameter.  However, if by_ref is true, the real type will
 485      be a pointer to this type.  */
 486   tree type;
 487
 488   /* Alias refrerence type to be used in MEM_REFs when adjusting caller
 489      arguments.  */
 490   tree alias_ptr_type;
 491
 492   /* The new declaration when creating/replacing a parameter.  Created by
 493      ipa_modify_formal_parameters, useful for functions modifying the body
 494      accordingly. */
 495   tree reduction;
 496
 497   /* New declaration of a substitute variable that we may use to replace all
 498      non-default-def ssa names when a parm decl is going away.  */
 499   tree new_ssa_base;
 500
 501   /* If non-NULL and the original parameter is to be removed (copy_param below
 502      is NULL), this is going to be its nonlocalized vars value.  */
 503   tree nonlocal_value;
 504
 505   /* Offset into the original parameter (for the cases when the new parameter
 506      is a component of an original one).  */
 507   HOST_WIDE_INT offset;
 508
 509   /* Zero based index of the original parameter this one is based on.  (ATM
 510      there is no way to insert a new parameter out of the blue because there is
 511      no need but if it arises the code can be easily exteded to do so.)  */
 512   int base_index;
 513
 514   /* This new parameter is an unmodified parameter at index base_index. */
 515   unsigned copy_param : 1;
 516
 517   /* This adjustment describes a parameter that is about to be removed
 518      completely.  Most users will probably need to book keep those so that they
 519      don't leave behinfd any non default def ssa names belonging to them.  */
 520   unsigned remove_param : 1;
 521
 522   /* The parameter is to be passed by reference.  */
 523   unsigned by_ref : 1;
 524 };
 525
 526 typedef struct ipa_parm_adjustment ipa_parm_adjustment_t;
 527 DEF_VEC_O (ipa_parm_adjustment_t);
 528 DEF_VEC_ALLOC_O (ipa_parm_adjustment_t, heap);
 529
 530 typedef VEC (ipa_parm_adjustment_t, heap) *ipa_parm_adjustment_vec;
 531
 532 VEC(tree, heap) *ipa_get_vector_of_formal_parms (tree fndecl);
 533 void ipa_modify_formal_parameters (tree fndecl, ipa_parm_adjustment_vec,
 534                                    const char *);
 535 void ipa_modify_call_arguments (struct cgraph_edge *, gimple,
 536                                 ipa_parm_adjustment_vec);
 537 ipa_parm_adjustment_vec ipa_combine_adjustments (ipa_parm_adjustment_vec,
 538                                                  ipa_parm_adjustment_vec);
 539 void ipa_dump_param_adjustments (FILE *, ipa_parm_adjustment_vec, tree);
 540
 541 void ipa_prop_write_jump_functions (cgraph_node_set set);
 542 void ipa_prop_read_jump_functions (void);
 543 void ipa_update_after_lto_read (void);
 544 int ipa_get_param_decl_index (struct ipa_node_params *, tree);
 545 tree ipa_value_from_jfunc (struct ipa_node_params *info,
 546                            struct ipa_jump_func *jfunc);
 547
 548
 549 /* From tree-sra.c:  */
 550 tree build_ref_for_offset (location_t, tree, HOST_WIDE_INT, tree,
 551                            gimple_stmt_iterator *, bool);
 552
 553 #endif /* IPA_PROP_H */