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 base_binfo */
  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 pass-through jump function.  */
  83
  84 struct GTY(()) ipa_pass_through_data
  85 {
  86   /* If an operation is to be performed on the original parameter, this is the
  87      second (constant) operand.  */
  88   tree operand;
  89   /* Number of the caller's formal parameter being passed.  */
  90   int formal_id;
  91   /* Operation that is performed on the argument before it is passed on.
  92      NOP_EXPR means no operation.  Otherwise oper must be a simple binary
  93      arithmetic operation where the caller's parameter is the first operand and
  94      operand field from this structure is the second one.  */
  95   enum tree_code operation;
  96 };
  97
  98 /* Structure holding data required to describe an ancestor pass-through
  99    jump function.  */
 100
 101 struct GTY(()) ipa_ancestor_jf_data
 102 {
 103   /* Offset of the field representing the ancestor.  */
 104   HOST_WIDE_INT offset;
 105   /* TYpe of the result.  */
 106   tree type;
 107   /* Number of the caller's formal parameter being passed.  */
 108   int formal_id;
 109 };
 110
 111 /* Structure holding a C++ member pointer constant.  Holds a pointer to the
 112    method and delta offset.  */
 113 struct GTY(()) ipa_member_ptr_cst
 114 {
 115   tree pfn;
 116   tree delta;
 117 };
 118
 119 /* A jump function for a callsite represents the values passed as actual
 120    arguments of the callsite. See enum jump_func_type for the various
 121    types of jump functions supported.  */
 122 struct GTY (()) ipa_jump_func
 123 {
 124   enum jump_func_type type;
 125   /* Represents a value of a jump function.  pass_through is used only in jump
 126      function context.  constant represents the actual constant in constant jump
 127      functions and member_cst holds constant c++ member functions.  */
 128   union jump_func_value
 129   {
 130     tree GTY ((tag ("IPA_JF_KNOWN_TYPE"))) base_binfo;
 131     tree GTY ((tag ("IPA_JF_CONST"))) constant;
 132     struct ipa_member_ptr_cst GTY ((tag ("IPA_JF_CONST_MEMBER_PTR"))) member_cst;
 133     struct ipa_pass_through_data GTY ((tag ("IPA_JF_PASS_THROUGH"))) pass_through;
 134     struct ipa_ancestor_jf_data GTY ((tag ("IPA_JF_ANCESTOR"))) ancestor;
 135   } GTY ((desc ("%1.type"))) value;
 136 };
 137
 138 /* Summary describing a single formal parameter.  */
 139
 140 struct ipa_param_descriptor
 141 {
 142   /* PARAM_DECL of this parameter.  */
 143   tree decl;
 144   /* The parameter is used.  */
 145   unsigned used : 1;
 146 };
 147
 148 typedef struct ipa_param_descriptor ipa_param_descriptor_t;
 149 DEF_VEC_O (ipa_param_descriptor_t);
 150 DEF_VEC_ALLOC_O (ipa_param_descriptor_t, heap);
 151 struct ipcp_lattice;
 152
 153 /* ipa_node_params stores information related to formal parameters of functions
 154    and some other information for interprocedural passes that operate on
 155    parameters (such as ipa-cp).  */
 156
 157 struct ipa_node_params
 158 {
 159   /* Information about individual formal parameters that are gathered when
 160      summaries are generated. */
 161   VEC (ipa_param_descriptor_t, heap) *descriptors;
 162   /* Pointer to an array of structures describing individual formal
 163      parameters.  */
 164   struct ipcp_lattice *lattices;
 165   /* Only for versioned nodes this field would not be NULL,
 166      it points to the node that IPA cp cloned from.  */
 167   struct cgraph_node *ipcp_orig_node;
 168   /* If this node is an ipa-cp clone, these are the known values that describe
 169      what it has been specialized for.  */
 170   VEC (tree, heap) *known_vals;
 171   /* Whether the param uses analysis has already been performed.  */
 172   unsigned uses_analysis_done : 1;
 173   /* Whether the function is enqueued in ipa-cp propagation stack.  */
 174   unsigned node_enqueued : 1;
 175   /* Whether we should create a specialized version based on values that are
 176      known to be constant in all contexts.  */
 177   unsigned clone_for_all_contexts : 1;
 178   /* Node has been completely replaced by clones and will be removed after
 179      ipa-cp is finished.  */
 180   unsigned node_dead : 1;
 181 };
 182
 183 /* ipa_node_params access functions.  Please use these to access fields that
 184    are or will be shared among various passes.  */
 185
 186 /* Return the number of formal parameters. */
 187
 188 static inline int
 189 ipa_get_param_count (struct ipa_node_params *info)
 190 {
 191   return VEC_length (ipa_param_descriptor_t, info->descriptors);
 192 }
 193
 194 /* Return the declaration of Ith formal parameter of the function corresponding
 195    to INFO.  Note there is no setter function as this array is built just once
 196    using ipa_initialize_node_params. */
 197
 198 static inline tree
 199 ipa_get_param (struct ipa_node_params *info, int i)
 200 {
 201   return VEC_index (ipa_param_descriptor_t, info->descriptors, i)->decl;
 202 }
 203
 204 /* Set the used flag corresponding to the Ith formal parameter of the function
 205    associated with INFO to VAL.  */
 206
 207 static inline void
 208 ipa_set_param_used (struct ipa_node_params *info, int i, bool val)
 209 {
 210   VEC_index (ipa_param_descriptor_t, info->descriptors, i)->used = val;
 211 }
 212
 213 /* Return the used flag corresponding to the Ith formal parameter of the
 214    function associated with INFO.  */
 215
 216 static inline bool
 217 ipa_is_param_used (struct ipa_node_params *info, int i)
 218 {
 219   return VEC_index (ipa_param_descriptor_t, info->descriptors, i)->used;
 220 }
 221
 222 /* ipa_edge_args stores information related to a callsite and particularly its
 223    arguments.  It can be accessed by the IPA_EDGE_REF macro.  */
 224 typedef struct GTY(()) ipa_edge_args
 225 {
 226   /* Number of actual arguments in this callsite.  When set to 0,
 227      this callsite's parameters would not be analyzed by the different
 228      stages of IPA CP.  */
 229   int argument_count;
 230   /* Array of the callsite's jump function of each parameter.  */
 231   struct ipa_jump_func GTY ((length ("%h.argument_count"))) *jump_functions;
 232 } ipa_edge_args_t;
 233
 234 /* ipa_edge_args access functions.  Please use these to access fields that
 235    are or will be shared among various passes.  */
 236
 237 /* Set the number of actual arguments. */
 238
 239 static inline void
 240 ipa_set_cs_argument_count (struct ipa_edge_args *args, int count)
 241 {
 242   args->argument_count = count;
 243 }
 244
 245 /* Return the number of actual arguments. */
 246
 247 static inline int
 248 ipa_get_cs_argument_count (struct ipa_edge_args *args)
 249 {
 250   return args->argument_count;
 251 }
 252
 253 /* Returns a pointer to the jump function for the ith argument.  Please note
 254    there is no setter function as jump functions are all set up in
 255    ipa_compute_jump_functions. */
 256
 257 static inline struct ipa_jump_func *
 258 ipa_get_ith_jump_func (struct ipa_edge_args *args, int i)
 259 {
 260   gcc_assert (i >= 0 && i <= args->argument_count);
 261   return &args->jump_functions[i];
 262 }
 263
 264 /* Vectors need to have typedefs of structures.  */
 265 typedef struct ipa_node_params ipa_node_params_t;
 266
 267 /* Types of vectors holding the infos.  */
 268 DEF_VEC_O (ipa_node_params_t);
 269 DEF_VEC_ALLOC_O (ipa_node_params_t, heap);
 270 DEF_VEC_O (ipa_edge_args_t);
 271 DEF_VEC_ALLOC_O (ipa_edge_args_t, gc);
 272
 273 /* Vector where the parameter infos are actually stored. */
 274 extern VEC (ipa_node_params_t, heap) *ipa_node_params_vector;
 275 /* Vector where the parameter infos are actually stored. */
 276 extern GTY(()) VEC (ipa_edge_args_t, gc) *ipa_edge_args_vector;
 277
 278 /* Return the associated parameter/argument info corresponding to the given
 279    node/edge.  */
 280 #define IPA_NODE_REF(NODE) (VEC_index (ipa_node_params_t, \
 281                                        ipa_node_params_vector, (NODE)->uid))
 282 #define IPA_EDGE_REF(EDGE) (VEC_index (ipa_edge_args_t, \
 283                                        ipa_edge_args_vector, (EDGE)->uid))
 284 /* This macro checks validity of index returned by
 285    ipa_get_param_decl_index function.  */
 286 #define IS_VALID_JUMP_FUNC_INDEX(I) ((I) != -1)
 287
 288 /* Creating and freeing ipa_node_params and ipa_edge_args.  */
 289 void ipa_create_all_node_params (void);
 290 void ipa_create_all_edge_args (void);
 291 void ipa_free_edge_args_substructures (struct ipa_edge_args *);
 292 void ipa_free_node_params_substructures (struct ipa_node_params *);
 293 void ipa_free_all_node_params (void);
 294 void ipa_free_all_edge_args (void);
 295 void ipa_create_all_structures_for_iinln (void);
 296 void ipa_free_all_structures_after_ipa_cp (void);
 297 void ipa_free_all_structures_after_iinln (void);
 298 void ipa_register_cgraph_hooks (void);
 299
 300 /* This function ensures the array of node param infos is big enough to
 301    accommodate a structure for all nodes and reallocates it if not.  */
 302
 303 static inline void
 304 ipa_check_create_node_params (void)
 305 {
 306   if (!ipa_node_params_vector)
 307     ipa_node_params_vector = VEC_alloc (ipa_node_params_t, heap,
 308                                         cgraph_max_uid);
 309
 310   if (VEC_length (ipa_node_params_t, ipa_node_params_vector)
 311       <= (unsigned) cgraph_max_uid)
 312     VEC_safe_grow_cleared (ipa_node_params_t, heap,
 313                            ipa_node_params_vector, cgraph_max_uid + 1);
 314 }
 315
 316 /* This function ensures the array of edge arguments infos is big enough to
 317    accommodate a structure for all edges and reallocates it if not.  */
 318
 319 static inline void
 320 ipa_check_create_edge_args (void)
 321 {
 322   if (!ipa_edge_args_vector)
 323     ipa_edge_args_vector = VEC_alloc (ipa_edge_args_t, gc,
 324                                       cgraph_edge_max_uid);
 325
 326   if (VEC_length (ipa_edge_args_t, ipa_edge_args_vector)
 327       <=  (unsigned) cgraph_edge_max_uid)
 328     VEC_safe_grow_cleared (ipa_edge_args_t, gc, ipa_edge_args_vector,
 329                            cgraph_edge_max_uid + 1);
 330 }
 331
 332 /* Returns true if the array of edge infos is large enough to accommodate an
 333    info for EDGE.  The main purpose of this function is that debug dumping
 334    function can check info availability without causing reallocations.  */
 335
 336 static inline bool
 337 ipa_edge_args_info_available_for_edge_p (struct cgraph_edge *edge)
 338 {
 339   return ((unsigned) edge->uid < VEC_length (ipa_edge_args_t,
 340                                              ipa_edge_args_vector));
 341 }
 342
 343 /* Function formal parameters related computations.  */
 344 void ipa_initialize_node_params (struct cgraph_node *node);
 345 bool ipa_propagate_indirect_call_infos (struct cgraph_edge *cs,
 346                                         VEC (cgraph_edge_p, heap) **new_edges);
 347
 348 /* Indirect edge and binfo processing.  */
 349 struct cgraph_edge *ipa_make_edge_direct_to_target (struct cgraph_edge *, tree);
 350
 351 /* Functions related to both.  */
 352 void ipa_analyze_node (struct cgraph_node *);
 353
 354 /* Debugging interface.  */
 355 void ipa_print_node_params (FILE *, struct cgraph_node *node);
 356 void ipa_print_all_params (FILE *);
 357 void ipa_print_node_jump_functions (FILE *f, struct cgraph_node *node);
 358 void ipa_print_all_jump_functions (FILE * f);
 359 void ipcp_verify_propagated_values (void);
 360
 361 extern alloc_pool ipcp_values_pool;
 362 extern alloc_pool ipcp_sources_pool;
 363
 364 /* Structure to describe transformations of formal parameters and actual
 365    arguments.  Each instance describes one new parameter and they are meant to
 366    be stored in a vector.  Additionally, most users will probably want to store
 367    adjustments about parameters that are being removed altogether so that SSA
 368    names belonging to them can be replaced by SSA names of an artificial
 369    variable.  */
 370 struct ipa_parm_adjustment
 371 {
 372   /* The original PARM_DECL itself, helpful for processing of the body of the
 373      function itself.  Intended for traversing function bodies.
 374      ipa_modify_formal_parameters, ipa_modify_call_arguments and
 375      ipa_combine_adjustments ignore this and use base_index.
 376      ipa_modify_formal_parameters actually sets this.  */
 377   tree base;
 378
 379   /* Type of the new parameter.  However, if by_ref is true, the real type will
 380      be a pointer to this type.  */
 381   tree type;
 382
 383   /* Alias refrerence type to be used in MEM_REFs when adjusting caller
 384      arguments.  */
 385   tree alias_ptr_type;
 386
 387   /* The new declaration when creating/replacing a parameter.  Created by
 388      ipa_modify_formal_parameters, useful for functions modifying the body
 389      accordingly. */
 390   tree reduction;
 391
 392   /* New declaration of a substitute variable that we may use to replace all
 393      non-default-def ssa names when a parm decl is going away.  */
 394   tree new_ssa_base;
 395
 396   /* If non-NULL and the original parameter is to be removed (copy_param below
 397      is NULL), this is going to be its nonlocalized vars value.  */
 398   tree nonlocal_value;
 399
 400   /* Offset into the original parameter (for the cases when the new parameter
 401      is a component of an original one).  */
 402   HOST_WIDE_INT offset;
 403
 404   /* Zero based index of the original parameter this one is based on.  (ATM
 405      there is no way to insert a new parameter out of the blue because there is
 406      no need but if it arises the code can be easily exteded to do so.)  */
 407   int base_index;
 408
 409   /* This new parameter is an unmodified parameter at index base_index. */
 410   unsigned copy_param : 1;
 411
 412   /* This adjustment describes a parameter that is about to be removed
 413      completely.  Most users will probably need to book keep those so that they
 414      don't leave behinfd any non default def ssa names belonging to them.  */
 415   unsigned remove_param : 1;
 416
 417   /* The parameter is to be passed by reference.  */
 418   unsigned by_ref : 1;
 419 };
 420
 421 typedef struct ipa_parm_adjustment ipa_parm_adjustment_t;
 422 DEF_VEC_O (ipa_parm_adjustment_t);
 423 DEF_VEC_ALLOC_O (ipa_parm_adjustment_t, heap);
 424
 425 typedef VEC (ipa_parm_adjustment_t, heap) *ipa_parm_adjustment_vec;
 426
 427 VEC(tree, heap) *ipa_get_vector_of_formal_parms (tree fndecl);
 428 void ipa_modify_formal_parameters (tree fndecl, ipa_parm_adjustment_vec,
 429                                    const char *);
 430 void ipa_modify_call_arguments (struct cgraph_edge *, gimple,
 431                                 ipa_parm_adjustment_vec);
 432 ipa_parm_adjustment_vec ipa_combine_adjustments (ipa_parm_adjustment_vec,
 433                                                  ipa_parm_adjustment_vec);
 434 void ipa_dump_param_adjustments (FILE *, ipa_parm_adjustment_vec, tree);
 435
 436 void ipa_prop_write_jump_functions (cgraph_node_set set);
 437 void ipa_prop_read_jump_functions (void);
 438 void ipa_update_after_lto_read (void);
 439 int ipa_get_param_decl_index (struct ipa_node_params *, tree);
 440 tree ipa_cst_from_jfunc (struct ipa_node_params *info,
 441                          struct ipa_jump_func *jfunc);
 442
 443
 444 /* From tree-sra.c:  */
 445 tree build_ref_for_offset (location_t, tree, HOST_WIDE_INT, tree,
 446                            gimple_stmt_iterator *, bool);
 447
 448 #endif /* IPA_PROP_H */