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
  29 /* The following definitions and interfaces are used by
  30    interprocedural analyses or parameters.  */
  31
  32 /* ipa-prop.c stuff (ipa-cp, indirect inlining):  */
  33
  34 /* A jump function for a callsite represents the values passed as actual
  35    arguments of the callsite. There are three main types of values :
  36
  37    Pass-through - the caller's formal parameter is passed as an actual
  38                   argument, possibly one simple operation performed on it.
  39    Constant     - a constant (is_gimple_ip_invariant)is passed as an actual
  40                   argument.
  41    Unknown      - neither of the above.
  42
  43    IPA_JF_CONST_MEMBER_PTR stands for C++ member pointers, it is a special
  44    constant in this regard.  Other constants are represented with IPA_JF_CONST.
  45
  46    IPA_JF_ANCESTOR is a special pass-through jump function, which means that
  47    the result is an address of a part of the object pointed to by the formal
  48    parameter to which the function refers.  It is mainly intended to represent
  49    getting addresses of of ancestor fields in C++
  50    (e.g. &this_1(D)->D.1766.D.1756).  Note that if the original pointer is
  51    NULL, ancestor jump function must behave like a simple pass-through.
  52
  53    Other pass-through functions can either simply pass on an unchanged formal
  54    parameter or can apply one simple binary operation to it (such jump
  55    functions are called polynomial).
  56
  57    IPA_JF_KNOWN_TYPE is a special type of an "unknown" function that applies
  58    only to pointer parameters.  It means that even though we cannot prove that
  59    the passed value is an interprocedural constant, we still know the exact
  60    type of the containing object which may be valuable for devirtualization.
  61
  62    Jump functions are computed in ipa-prop.c by function
  63    update_call_notes_after_inlining.  Some information can be lost and jump
  64    functions degraded accordingly when inlining, see
  65    update_call_notes_after_inlining in the same file.  */
  66
  67 enum jump_func_type
  68 {
  69   IPA_JF_UNKNOWN = 0,  /* newly allocated and zeroed jump functions default */
  70   IPA_JF_KNOWN_TYPE,        /* represented by field base_binfo */
  71   IPA_JF_CONST,             /* represented by field costant */
  72   IPA_JF_CONST_MEMBER_PTR,  /* represented by field member_cst */
  73   IPA_JF_PASS_THROUGH,      /* represented by field pass_through */
  74   IPA_JF_ANCESTOR           /* represented by field ancestor */
  75 };
  76
  77 /* Structure holding data required to describe a pass-through jump function.  */
  78
  79 struct GTY(()) ipa_pass_through_data
  80 {
  81   /* If an operation is to be performed on the original parameter, this is the
  82      second (constant) operand.  */
  83   tree operand;
  84   /* Number of the caller's formal parameter being passed.  */
  85   int formal_id;
  86   /* Operation that is performed on the argument before it is passed on.
  87      NOP_EXPR means no operation.  Otherwise oper must be a simple binary
  88      arithmetic operation where the caller's parameter is the first operand and
  89      operand field from this structure is the second one.  */
  90   enum tree_code operation;
  91 };
  92
  93 /* Structure holding data required to describe an ancestor pass-through
  94    jump function.  */
  95
  96 struct GTY(()) ipa_ancestor_jf_data
  97 {
  98   /* Offset of the field representing the ancestor.  */
  99   HOST_WIDE_INT offset;
 100   /* TYpe of the result.  */
 101   tree type;
 102   /* Number of the caller's formal parameter being passed.  */
 103   int formal_id;
 104 };
 105
 106 /* Structure holding a C++ member pointer constant.  Holds a pointer to the
 107    method and delta offset.  */
 108 struct GTY(()) ipa_member_ptr_cst
 109 {
 110   tree pfn;
 111   tree delta;
 112 };
 113
 114 /* A jump function for a callsite represents the values passed as actual
 115    arguments of the callsite. See enum jump_func_type for the various
 116    types of jump functions supported.  */
 117 struct GTY (()) ipa_jump_func
 118 {
 119   enum jump_func_type type;
 120   /* Represents a value of a jump function.  pass_through is used only in jump
 121      function context.  constant represents the actual constant in constant jump
 122      functions and member_cst holds constant c++ member functions.  */
 123   union jump_func_value
 124   {
 125     tree GTY ((tag ("IPA_JF_KNOWN_TYPE"))) base_binfo;
 126     tree GTY ((tag ("IPA_JF_CONST"))) constant;
 127     struct ipa_member_ptr_cst GTY ((tag ("IPA_JF_CONST_MEMBER_PTR"))) member_cst;
 128     struct ipa_pass_through_data GTY ((tag ("IPA_JF_PASS_THROUGH"))) pass_through;
 129     struct ipa_ancestor_jf_data GTY ((tag ("IPA_JF_ANCESTOR"))) ancestor;
 130   } GTY ((desc ("%1.type"))) value;
 131 };
 132
 133 /* All formal parameters in the program have a lattice associated with it
 134    computed by the interprocedural stage of IPCP.
 135    There are three main values of the lattice:
 136    IPA_TOP - unknown,
 137    IPA_BOTTOM - variable,
 138    IPA_CONST_VALUE - simple scalar constant,
 139
 140    We also use this type to propagate types accross the call graph for the
 141    purpose of devirtualization.  In that case, IPA_CONST_VALUE denotes a known
 142    type, rather than a constant.  */
 143 enum ipa_lattice_type
 144 {
 145   IPA_BOTTOM,
 146   IPA_CONST_VALUE,
 147   IPA_TOP
 148 };
 149
 150 /* All formal parameters in the program have a cval computed by
 151    the interprocedural stage of IPCP. See enum ipa_lattice_type for
 152    the various types of lattices supported */
 153 struct ipcp_lattice
 154 {
 155   enum ipa_lattice_type type;
 156   tree constant;
 157 };
 158
 159 /* Structure describing a single formal parameter.  */
 160 struct ipa_param_descriptor
 161 {
 162   /* IPA-CP lattice.  */
 163   struct ipcp_lattice ipcp_lattice;
 164   /* PARAM_DECL of this parameter.  */
 165   tree decl;
 166   /* Vector of BINFOs of types that this argument might encounter.  NULL
 167      basically means a top value, bottom is marked by the cannot_devirtualize
 168      flag below.*/
 169   VEC (tree, heap) *types;
 170   /* The parameter is used.  */
 171   unsigned used : 1;
 172   /* Set when parameter type cannot be used for devirtualization.  */
 173   unsigned cannot_devirtualize : 1;
 174 };
 175
 176 /* ipa_node_params stores information related to formal parameters of functions
 177    and some other information for interprocedural passes that operate on
 178    parameters (such as ipa-cp).  */
 179 struct ipa_node_params
 180 {
 181   /* Number of formal parameters of this function.  When set to 0, this
 182      function's parameters would not be analyzed by IPA CP.  */
 183   int param_count;
 184   /* Whether this function is called with variable number of actual
 185      arguments.  */
 186   unsigned called_with_var_arguments : 1;
 187   /* Whether the param uses analysis has already been performed.  */
 188   unsigned uses_analysis_done : 1;
 189   /* Whether the function is enqueued in an ipa_func_list.  */
 190   unsigned node_enqueued : 1;
 191   /* Pointer to an array of structures describing individual formal
 192      parameters.  */
 193   struct ipa_param_descriptor *params;
 194   /* Only for versioned nodes this field would not be NULL,
 195      it points to the node that IPA cp cloned from.  */
 196   struct cgraph_node *ipcp_orig_node;
 197   /* Meaningful only for original functions.  Expresses the
 198      ratio between the direct calls and sum of all invocations of
 199      this function (given by profiling info).  It is used to calculate
 200      the profiling information of the original function and the versioned
 201      one.  */
 202   gcov_type count_scale;
 203 };
 204
 205 /* ipa_node_params access functions.  Please use these to access fields that
 206    are or will be shared among various passes.  */
 207
 208 /* Set the number of formal parameters. */
 209
 210 static inline void
 211 ipa_set_param_count (struct ipa_node_params *info, int count)
 212 {
 213   info->param_count = count;
 214 }
 215
 216 /* Return the number of formal parameters. */
 217
 218 static inline int
 219 ipa_get_param_count (struct ipa_node_params *info)
 220 {
 221   return info->param_count;
 222 }
 223
 224 /* Return the declaration of Ith formal parameter of the function corresponding
 225    to INFO.  Note there is no setter function as this array is built just once
 226    using ipa_initialize_node_params. */
 227
 228 static inline tree
 229 ipa_get_param (struct ipa_node_params *info, int i)
 230 {
 231   return info->params[i].decl;
 232 }
 233
 234 /* Return the used flag corresponding to the Ith formal parameter of
 235    the function associated with INFO.  */
 236
 237 static inline bool
 238 ipa_is_param_used (struct ipa_node_params *info, int i)
 239 {
 240   return info->params[i].used;
 241 }
 242
 243 /* Return the cannot_devirtualize flag corresponding to the Ith formal
 244    parameter of the function associated with INFO.  The corresponding function
 245    to set the flag is ipa_set_param_cannot_devirtualize.  */
 246
 247 static inline bool
 248 ipa_param_cannot_devirtualize_p (struct ipa_node_params *info, int i)
 249 {
 250   return info->params[i].cannot_devirtualize;
 251 }
 252
 253 /* Return true iff the vector of possible types of the Ith formal parameter of
 254    the function associated with INFO is empty.  */
 255
 256 static inline bool
 257 ipa_param_types_vec_empty (struct ipa_node_params *info, int i)
 258 {
 259   return info->params[i].types == NULL;
 260 }
 261
 262 /* Flag this node as having callers with variable number of arguments.  */
 263
 264 static inline void
 265 ipa_set_called_with_variable_arg (struct ipa_node_params *info)
 266 {
 267   info->called_with_var_arguments = 1;
 268 }
 269
 270 /* Have we detected this node was called with variable number of arguments? */
 271
 272 static inline bool
 273 ipa_is_called_with_var_arguments (struct ipa_node_params *info)
 274 {
 275   return info->called_with_var_arguments;
 276 }
 277
 278
 279
 280 /* ipa_edge_args stores information related to a callsite and particularly its
 281    arguments.  It can be accessed by the IPA_EDGE_REF macro.  */
 282 typedef struct GTY(()) ipa_edge_args
 283 {
 284   /* Number of actual arguments in this callsite.  When set to 0,
 285      this callsite's parameters would not be analyzed by the different
 286      stages of IPA CP.  */
 287   int argument_count;
 288   /* Array of the callsite's jump function of each parameter.  */
 289   struct ipa_jump_func GTY ((length ("%h.argument_count"))) *jump_functions;
 290 } ipa_edge_args_t;
 291
 292 /* ipa_edge_args access functions.  Please use these to access fields that
 293    are or will be shared among various passes.  */
 294
 295 /* Set the number of actual arguments. */
 296
 297 static inline void
 298 ipa_set_cs_argument_count (struct ipa_edge_args *args, int count)
 299 {
 300   args->argument_count = count;
 301 }
 302
 303 /* Return the number of actual arguments. */
 304
 305 static inline int
 306 ipa_get_cs_argument_count (struct ipa_edge_args *args)
 307 {
 308   return args->argument_count;
 309 }
 310
 311 /* Returns a pointer to the jump function for the ith argument.  Please note
 312    there is no setter function as jump functions are all set up in
 313    ipa_compute_jump_functions. */
 314
 315 static inline struct ipa_jump_func *
 316 ipa_get_ith_jump_func (struct ipa_edge_args *args, int i)
 317 {
 318   return &args->jump_functions[i];
 319 }
 320
 321 /* Vectors need to have typedefs of structures.  */
 322 typedef struct ipa_node_params ipa_node_params_t;
 323
 324 /* Types of vectors holding the infos.  */
 325 DEF_VEC_O (ipa_node_params_t);
 326 DEF_VEC_ALLOC_O (ipa_node_params_t, heap);
 327 DEF_VEC_O (ipa_edge_args_t);
 328 DEF_VEC_ALLOC_O (ipa_edge_args_t, gc);
 329
 330 /* Vector where the parameter infos are actually stored. */
 331 extern VEC (ipa_node_params_t, heap) *ipa_node_params_vector;
 332 /* Vector where the parameter infos are actually stored. */
 333 extern GTY(()) VEC (ipa_edge_args_t, gc) *ipa_edge_args_vector;
 334
 335 /* Return the associated parameter/argument info corresponding to the given
 336    node/edge.  */
 337 #define IPA_NODE_REF(NODE) (VEC_index (ipa_node_params_t, \
 338                                        ipa_node_params_vector, (NODE)->uid))
 339 #define IPA_EDGE_REF(EDGE) (VEC_index (ipa_edge_args_t, \
 340                                        ipa_edge_args_vector, (EDGE)->uid))
 341 /* This macro checks validity of index returned by
 342    ipa_get_param_decl_index function.  */
 343 #define IS_VALID_JUMP_FUNC_INDEX(I) ((I) != -1)
 344
 345 /* Creating and freeing ipa_node_params and ipa_edge_args.  */
 346 void ipa_create_all_node_params (void);
 347 void ipa_create_all_edge_args (void);
 348 void ipa_free_edge_args_substructures (struct ipa_edge_args *);
 349 void ipa_free_node_params_substructures (struct ipa_node_params *);
 350 void ipa_free_all_node_params (void);
 351 void ipa_free_all_edge_args (void);
 352 void ipa_create_all_structures_for_iinln (void);
 353 void ipa_free_all_structures_after_ipa_cp (void);
 354 void ipa_free_all_structures_after_iinln (void);
 355 void ipa_register_cgraph_hooks (void);
 356
 357 /* This function ensures the array of node param infos is big enough to
 358    accommodate a structure for all nodes and reallocates it if not.  */
 359
 360 static inline void
 361 ipa_check_create_node_params (void)
 362 {
 363   if (!ipa_node_params_vector)
 364     ipa_node_params_vector = VEC_alloc (ipa_node_params_t, heap,
 365                                         cgraph_max_uid);
 366
 367   if (VEC_length (ipa_node_params_t, ipa_node_params_vector)
 368       <= (unsigned) cgraph_max_uid)
 369     VEC_safe_grow_cleared (ipa_node_params_t, heap,
 370                            ipa_node_params_vector, cgraph_max_uid + 1);
 371 }
 372
 373 /* This function ensures the array of edge arguments infos is big enough to
 374    accommodate a structure for all edges and reallocates it if not.  */
 375
 376 static inline void
 377 ipa_check_create_edge_args (void)
 378 {
 379   if (!ipa_edge_args_vector)
 380     ipa_edge_args_vector = VEC_alloc (ipa_edge_args_t, gc,
 381                                       cgraph_edge_max_uid);
 382
 383   if (VEC_length (ipa_edge_args_t, ipa_edge_args_vector)
 384       <=  (unsigned) cgraph_edge_max_uid)
 385     VEC_safe_grow_cleared (ipa_edge_args_t, gc, ipa_edge_args_vector,
 386                            cgraph_edge_max_uid + 1);
 387 }
 388
 389 /* Returns true if the array of edge infos is large enough to accommodate an
 390    info for EDGE.  The main purpose of this function is that debug dumping
 391    function can check info availability without causing reallocations.  */
 392
 393 static inline bool
 394 ipa_edge_args_info_available_for_edge_p (struct cgraph_edge *edge)
 395 {
 396   return ((unsigned) edge->uid < VEC_length (ipa_edge_args_t,
 397                                              ipa_edge_args_vector));
 398 }
 399
 400 /* A function list element.  It is used to create a temporary worklist used in
 401    the propagation stage of IPCP. (can be used for more IPA optimizations)  */
 402 struct ipa_func_list
 403 {
 404   struct cgraph_node *node;
 405   struct ipa_func_list *next;
 406 };
 407
 408 /* ipa_func_list interface.  */
 409 struct ipa_func_list *ipa_init_func_list (void);
 410 void ipa_push_func_to_list_1 (struct ipa_func_list **, struct cgraph_node *,
 411                               struct ipa_node_params *);
 412 struct cgraph_node *ipa_pop_func_from_list (struct ipa_func_list **);
 413
 414 /* Add cgraph NODE to the worklist WL if it is not already in one.  */
 415
 416 static inline void
 417 ipa_push_func_to_list (struct ipa_func_list **wl, struct cgraph_node *node)
 418 {
 419   struct ipa_node_params *info = IPA_NODE_REF (node);
 420
 421   if (!info->node_enqueued)
 422     ipa_push_func_to_list_1 (wl, node, info);
 423 }
 424
 425 void ipa_analyze_node (struct cgraph_node *);
 426
 427 /* Function formal parameters related computations.  */
 428 void ipa_initialize_node_params (struct cgraph_node *node);
 429 bool ipa_propagate_indirect_call_infos (struct cgraph_edge *cs,
 430                                         VEC (cgraph_edge_p, heap) **new_edges);
 431
 432 /* Indirect edge and binfo processing.  */
 433 struct cgraph_edge *ipa_make_edge_direct_to_target (struct cgraph_edge *, tree,
 434                                                     tree);
 435
 436
 437 /* Debugging interface.  */
 438 void ipa_print_node_params (FILE *, struct cgraph_node *node);
 439 void ipa_print_all_params (FILE *);
 440 void ipa_print_node_jump_functions (FILE *f, struct cgraph_node *node);
 441 void ipa_print_all_jump_functions (FILE * f);
 442
 443 /* Structure to describe transformations of formal parameters and actual
 444    arguments.  Each instance describes one new parameter and they are meant to
 445    be stored in a vector.  Additionally, most users will probably want to store
 446    adjustments about parameters that are being removed altogether so that SSA
 447    names belonging to them can be replaced by SSA names of an artificial
 448    variable.  */
 449 struct ipa_parm_adjustment
 450 {
 451   /* The original PARM_DECL itself, helpful for processing of the body of the
 452      function itself.  Intended for traversing function bodies.
 453      ipa_modify_formal_parameters, ipa_modify_call_arguments and
 454      ipa_combine_adjustments ignore this and use base_index.
 455      ipa_modify_formal_parameters actually sets this.  */
 456   tree base;
 457
 458   /* Type of the new parameter.  However, if by_ref is true, the real type will
 459      be a pointer to this type.  */
 460   tree type;
 461
 462   /* Alias refrerence type to be used in MEM_REFs when adjusting caller
 463      arguments.  */
 464   tree alias_ptr_type;
 465
 466   /* The new declaration when creating/replacing a parameter.  Created by
 467      ipa_modify_formal_parameters, useful for functions modifying the body
 468      accordingly. */
 469   tree reduction;
 470
 471   /* New declaration of a substitute variable that we may use to replace all
 472      non-default-def ssa names when a parm decl is going away.  */
 473   tree new_ssa_base;
 474
 475   /* If non-NULL and the original parameter is to be removed (copy_param below
 476      is NULL), this is going to be its nonlocalized vars value.  */
 477   tree nonlocal_value;
 478
 479   /* Offset into the original parameter (for the cases when the new parameter
 480      is a component of an original one).  */
 481   HOST_WIDE_INT offset;
 482
 483   /* Zero based index of the original parameter this one is based on.  (ATM
 484      there is no way to insert a new parameter out of the blue because there is
 485      no need but if it arises the code can be easily exteded to do so.)  */
 486   int base_index;
 487
 488   /* This new parameter is an unmodified parameter at index base_index. */
 489   unsigned copy_param : 1;
 490
 491   /* This adjustment describes a parameter that is about to be removed
 492      completely.  Most users will probably need to book keep those so that they
 493      don't leave behinfd any non default def ssa names belonging to them.  */
 494   unsigned remove_param : 1;
 495
 496   /* The parameter is to be passed by reference.  */
 497   unsigned by_ref : 1;
 498 };
 499
 500 typedef struct ipa_parm_adjustment ipa_parm_adjustment_t;
 501 DEF_VEC_O (ipa_parm_adjustment_t);
 502 DEF_VEC_ALLOC_O (ipa_parm_adjustment_t, heap);
 503
 504 typedef VEC (ipa_parm_adjustment_t, heap) *ipa_parm_adjustment_vec;
 505
 506 VEC(tree, heap) *ipa_get_vector_of_formal_parms (tree fndecl);
 507 void ipa_modify_formal_parameters (tree fndecl, ipa_parm_adjustment_vec,
 508                                    const char *);
 509 void ipa_modify_call_arguments (struct cgraph_edge *, gimple,
 510                                 ipa_parm_adjustment_vec);
 511 ipa_parm_adjustment_vec ipa_combine_adjustments (ipa_parm_adjustment_vec,
 512                                                  ipa_parm_adjustment_vec);
 513 void ipa_dump_param_adjustments (FILE *, ipa_parm_adjustment_vec, tree);
 514
 515 void ipa_prop_write_jump_functions (cgraph_node_set set);
 516 void ipa_prop_read_jump_functions (void);
 517 void ipa_update_after_lto_read (void);
 518
 519 /* From tree-sra.c:  */
 520 tree build_ref_for_offset (location_t, tree, HOST_WIDE_INT, tree,
 521                            gimple_stmt_iterator *, bool);
 522
 523 #endif /* IPA_PROP_H */