gcc/ipa-prop.h

   1 /* Interprocedural analyses.
   2    Copyright (C) 2005, 2007, 2008 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 3, 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 COPYING3.  If not see
  18 <http://www.gnu.org/licenses/>.  */
  19
  20 #ifndef IPA_PROP_H
  21 #define IPA_PROP_H
  22
  23 #include "tree.h"
  24 #include "vec.h"
  25 #include "cgraph.h"
  26
  27 /* The following definitions and interfaces are used by
  28    interprocedural analyses or parameters.  */
  29
  30 /* ipa-prop.c stuff (ipa-cp, indirect inlining):  */
  31
  32 /* A jump function for a callsite represents the values passed as actual
  33    arguments of the callsite. There are three main types of values :
  34
  35    Pass-through - the caller's formal parameter is passed as an actual
  36                   argument, possibly one simple operation performed on it.
  37    Constant     - a constant (is_gimple_ip_invariant)is passed as an actual
  38                   argument.
  39    Unknown      - neither of the above.
  40
  41    IPA_JF_CONST_MEMBER_PTR stands for C++ member pointers, other constants are
  42    represented with IPA_JF_CONST.
  43
  44    In addition to "ordinary" pass through functions represented by
  45    IPA_JF_PASS_THROUGH, IPA_JF_ANCESTOR represents getting addresses of of
  46    ancestor fields in C++ (e.g. &this_1(D)->D.1766.D.1756).  */
  47 enum jump_func_type
  48 {
  49   IPA_JF_UNKNOWN = 0,  /* newly allocated and zeroed jump functions default */
  50   IPA_JF_CONST,
  51   IPA_JF_CONST_MEMBER_PTR,
  52   IPA_JF_PASS_THROUGH,
  53   IPA_JF_ANCESTOR
  54 };
  55
  56 /* All formal parameters in the program have a lattice associated with it
  57    computed by the interprocedural stage of IPCP.
  58    There are three main values of the lattice:
  59    IPA_TOP - unknown,
  60    IPA_BOTTOM - non constant,
  61    IPA_CONST_VALUE - simple scalar constant,
  62    Cval of formal f will have a constant value if all callsites to this
  63    function have the same constant value passed to f.
  64    Integer and real constants are represented as IPA_CONST_VALUE.  */
  65 enum ipa_lattice_type
  66 {
  67   IPA_BOTTOM,
  68   IPA_CONST_VALUE,
  69   IPA_TOP
  70 };
  71
  72
  73 /* Structure holding data required to describe a pass-through jump function.  */
  74
  75 struct GTY(()) ipa_pass_through_data
  76 {
  77   /* If an operation is to be performed on the original parameter, this is the
  78      second (constant) operand.  */
  79   tree operand;
  80   /* Number of the caller's formal parameter being passed.  */
  81   int formal_id;
  82   /* Operation that is performed on the argument before it is passed on.
  83      NOP_EXPR means no operation.  Otherwise oper must be a simple binary
  84      arithmetic operation where the caller's parameter is the first operand and
  85      operand field from this structure is the second one.  */
  86   enum tree_code operation;
  87 };
  88
  89 /* Structure holding data required to describe and ancestor pass throu
  90    funkci.  */
  91
  92 struct GTY(()) ipa_ancestor_jf_data
  93 {
  94   /* Offset of the field representing the ancestor.  */
  95   HOST_WIDE_INT offset;
  96   /* TYpe of the result.  */
  97   tree type;
  98   /* Number of the caller's formal parameter being passed.  */
  99   int formal_id;
 100 };
 101
 102 /* Structure holding a C++ member pointer constant.  Holds a pointer to the
 103    method and delta offset.  */
 104 struct GTY(()) ipa_member_ptr_cst
 105 {
 106   tree pfn;
 107   tree delta;
 108 };
 109
 110 /* A jump function for a callsite represents the values passed as actual
 111    arguments of the callsite. See enum jump_func_type for the various
 112    types of jump functions supported.  */
 113 struct GTY (()) ipa_jump_func
 114 {
 115   enum jump_func_type type;
 116   /* Represents a value of a jump function.  pass_through is used only in jump
 117      function context.  constant represents the actual constant in constant jump
 118      functions and member_cst holds constant c++ member functions.  */
 119   union jump_func_value
 120   {
 121     tree GTY ((tag ("IPA_JF_CONST"))) constant;
 122     struct ipa_pass_through_data GTY ((tag ("IPA_JF_PASS_THROUGH"))) pass_through;
 123     struct ipa_ancestor_jf_data GTY ((tag ("IPA_JF_ANCESTOR"))) ancestor;
 124     struct ipa_member_ptr_cst GTY ((tag ("IPA_JF_CONST_MEMBER_PTR"))) member_cst;
 125   } GTY ((desc ("%1.type"))) value;
 126 };
 127
 128 /* All formal parameters in the program have a cval computed by
 129    the interprocedural stage of IPCP. See enum ipa_lattice_type for
 130    the various types of lattices supported */
 131 struct ipcp_lattice
 132 {
 133   enum ipa_lattice_type type;
 134   tree constant;
 135 };
 136
 137 /* Each instance of the following  structure describes a statement that calls a
 138    function parameter.  Those referring  to statements within the same function
 139    are linked in a list.  */
 140 struct ipa_param_call_note
 141 {
 142   /* Linked list's next */
 143   struct ipa_param_call_note *next;
 144   /* Statement that contains the call to the parameter above.  */
 145   gimple stmt;
 146   /* Index of the parameter that is called.  */
 147   int formal_id;
 148   /* Expected number of executions: calculated in profile.c.  */
 149   gcov_type count;
 150   /* Expected frequency of executions within the function. see cgraph_edge in
 151      cgraph.h for more on this. */
 152   int frequency;
 153   /* Depth of loop nest, 1 means no loop nest.  */
 154   int loop_nest;
 155   /* Set when we have already found the target to be a compile time constant
 156      and turned this into an edge or when the note was found unusable for some
 157      reason.  */
 158   bool processed;
 159 };
 160
 161 /* Structure describing a single formal parameter.  */
 162 struct ipa_param_descriptor
 163 {
 164   /* IPA-CP lattice.  */
 165   struct ipcp_lattice ipcp_lattice;
 166   /* PARAM_DECL of this parameter.  */
 167   tree decl;
 168   /* Whether the value parameter has been modified within the function.  */
 169   unsigned modified : 1;
 170   /* Whether the parameter has been used as a call destination. */
 171   unsigned called : 1;
 172 };
 173
 174 /* ipa_node_params stores information related to formal parameters of functions
 175    and some other information for interprocedural passes that operate on
 176    parameters (such as ipa-cp).  */
 177 struct ipa_node_params
 178 {
 179   /* Number of formal parameters of this function.  When set to 0,
 180      this function's parameters would not be analyzed by the different
 181      stages of IPA CP.  */
 182   int param_count;
 183   /* Pointer to an array of structures describing individual formal
 184      parameters.  */
 185   struct ipa_param_descriptor *params;
 186   /* List of structures enumerating calls to a formal parameter.  */
 187   struct ipa_param_call_note *param_calls;
 188   /* Only for versioned nodes this field would not be NULL,
 189      it points to the node that IPA cp cloned from.  */
 190   struct cgraph_node *ipcp_orig_node;
 191   /* Meaningful only for original functions.  Expresses the
 192      ratio between the direct calls and sum of all invocations of
 193      this function (given by profiling info).  It is used to calculate
 194      the profiling information of the original function and the versioned
 195      one.  */
 196   gcov_type count_scale;
 197
 198   /* Whether this function is called with variable number of actual
 199      arguments.  */
 200   unsigned called_with_var_arguments : 1;
 201   /* Whether the modification analysis has already been performed. */
 202   unsigned modification_analysis_done : 1;
 203   /* Whether the param uses analysis has already been performed.  */
 204   unsigned uses_analysis_done : 1;
 205   /* Whether the function is enqueued in an ipa_func_list.  */
 206   unsigned node_enqueued : 1;
 207 };
 208
 209 /* ipa_node_params access functions.  Please use these to access fields that
 210    are or will be shared among various passes.  */
 211
 212 /* Set the number of formal parameters. */
 213
 214 static inline void
 215 ipa_set_param_count (struct ipa_node_params *info, int count)
 216 {
 217   info->param_count = count;
 218 }
 219
 220 /* Return the number of formal parameters. */
 221
 222 static inline int
 223 ipa_get_param_count (struct ipa_node_params *info)
 224 {
 225   return info->param_count;
 226 }
 227
 228 /* Return the declaration of Ith formal parameter of the function corresponding
 229    to INFO.  Note there is no setter function as this array is built just once
 230    using ipa_initialize_node_params. */
 231
 232 static inline tree
 233 ipa_get_param (struct ipa_node_params *info, int i)
 234 {
 235   return info->params[i].decl;
 236 }
 237
 238 /* Return the modification flag corresponding to the Ith formal parameter of
 239    the function associated with INFO.  Note that there is no setter method as
 240    the goal is to set all flags when building the array in
 241    ipa_detect_param_modifications.  */
 242
 243 static inline bool
 244 ipa_is_param_modified (struct ipa_node_params *info, int i)
 245 {
 246   return info->params[i].modified;
 247 }
 248
 249 /* Return the called flag corresponding to the Ith formal parameter of the
 250    function associated with INFO.  Note that there is no setter method as the
 251    goal is to set all flags when building the array in
 252    ipa_detect_called_params.  */
 253
 254 static inline bool
 255 ipa_is_param_called (struct ipa_node_params *info, int i)
 256 {
 257   return info->params[i].called;
 258 }
 259
 260 /* Flag this node as having callers with variable number of arguments.  */
 261
 262 static inline void
 263 ipa_set_called_with_variable_arg (struct ipa_node_params *info)
 264 {
 265   info->called_with_var_arguments = 1;
 266 }
 267
 268 /* Have we detected this node was called with variable number of arguments? */
 269
 270 static inline bool
 271 ipa_is_called_with_var_arguments (struct ipa_node_params *info)
 272 {
 273   return info->called_with_var_arguments;
 274 }
 275
 276
 277
 278 /* ipa_edge_args stores information related to a callsite and particularly
 279    its arguments. It is pointed to by a field in the
 280    callsite's corresponding cgraph_edge.  */
 281 typedef struct GTY(()) ipa_edge_args
 282 {
 283   /* Number of actual arguments in this callsite.  When set to 0,
 284      this callsite's parameters would not be analyzed by the different
 285      stages of IPA CP.  */
 286   int argument_count;
 287   /* Array of the callsite's jump function of each parameter.  */
 288   struct ipa_jump_func GTY ((length ("%h.argument_count"))) *jump_functions;
 289 } ipa_edge_args_t;
 290
 291 /* ipa_edge_args access functions.  Please use these to access fields that
 292    are or will be shared among various passes.  */
 293
 294 /* Set the number of actual arguments. */
 295
 296 static inline void
 297 ipa_set_cs_argument_count (struct ipa_edge_args *args, int count)
 298 {
 299   args->argument_count = count;
 300 }
 301
 302 /* Return the number of actual arguments. */
 303
 304 static inline int
 305 ipa_get_cs_argument_count (struct ipa_edge_args *args)
 306 {
 307   return args->argument_count;
 308 }
 309
 310 /* Returns a pointer to the jump function for the ith argument.  Please note
 311    there is no setter function as jump functions are all set up in
 312    ipa_compute_jump_functions. */
 313
 314 static inline struct ipa_jump_func *
 315 ipa_get_ith_jump_func (struct ipa_edge_args *args, int i)
 316 {
 317   return &args->jump_functions[i];
 318 }
 319
 320 /* Vectors need to have typedefs of structures.  */
 321 typedef struct ipa_node_params ipa_node_params_t;
 322
 323 /* Types of vectors holding the infos.  */
 324 DEF_VEC_O (ipa_node_params_t);
 325 DEF_VEC_ALLOC_O (ipa_node_params_t, heap);
 326 DEF_VEC_O (ipa_edge_args_t);
 327 DEF_VEC_ALLOC_O (ipa_edge_args_t, gc);
 328
 329 /* Vector where the parameter infos are actually stored. */
 330 extern VEC (ipa_node_params_t, heap) *ipa_node_params_vector;
 331 /* Vector where the parameter infos are actually stored. */
 332 extern GTY(()) VEC (ipa_edge_args_t, gc) *ipa_edge_args_vector;
 333
 334 /* Return the associated parameter/argument info corresponding to the given
 335    node/edge.  */
 336 #define IPA_NODE_REF(NODE) (VEC_index (ipa_node_params_t, \
 337                                        ipa_node_params_vector, (NODE)->uid))
 338 #define IPA_EDGE_REF(EDGE) (VEC_index (ipa_edge_args_t, \
 339                                        ipa_edge_args_vector, (EDGE)->uid))
 340 /* This macro checks validity of index returned by
 341    ipa_get_param_decl_index function.  */
 342 #define IS_VALID_JUMP_FUNC_INDEX(I) ((I) != -1)
 343
 344 /* Creating and freeing ipa_node_params and ipa_edge_args.  */
 345 void ipa_create_all_node_params (void);
 346 void ipa_create_all_edge_args (void);
 347 void ipa_free_edge_args_substructures (struct ipa_edge_args *);
 348 void ipa_free_node_params_substructures (struct ipa_node_params *);
 349 void ipa_free_all_node_params (void);
 350 void ipa_free_all_edge_args (void);
 351 void free_all_ipa_structures_after_ipa_cp (void);
 352 void free_all_ipa_structures_after_iinln (void);
 353 void ipa_register_cgraph_hooks (void);
 354
 355 /* This function ensures the array of node param infos is big enough to
 356    accommodate a structure for all nodes and reallocates it if not.  */
 357
 358 static inline void
 359 ipa_check_create_node_params (void)
 360 {
 361   if (!ipa_node_params_vector)
 362     ipa_node_params_vector = VEC_alloc (ipa_node_params_t, heap,
 363                                         cgraph_max_uid);
 364
 365   if (VEC_length (ipa_node_params_t, ipa_node_params_vector)
 366       <= (unsigned) cgraph_max_uid)
 367     VEC_safe_grow_cleared (ipa_node_params_t, heap,
 368                            ipa_node_params_vector, cgraph_max_uid + 1);
 369 }
 370
 371 /* This function ensures the array of edge arguments infos is big enough to
 372    accommodate a structure for all edges and reallocates it if not.  */
 373
 374 static inline void
 375 ipa_check_create_edge_args (void)
 376 {
 377   if (!ipa_edge_args_vector)
 378     ipa_edge_args_vector = VEC_alloc (ipa_edge_args_t, gc,
 379                                       cgraph_edge_max_uid);
 380
 381   if (VEC_length (ipa_edge_args_t, ipa_edge_args_vector)
 382       <=  (unsigned) cgraph_edge_max_uid)
 383     VEC_safe_grow_cleared (ipa_edge_args_t, gc, ipa_edge_args_vector,
 384                            cgraph_edge_max_uid + 1);
 385 }
 386
 387 /* Returns true if the array of edge infos is large enough to accommodate an
 388    info for EDGE.  The main purpose of this function is that debug dumping
 389    function can check info availability without causing reallocations.  */
 390
 391 static inline bool
 392 ipa_edge_args_info_available_for_edge_p (struct cgraph_edge *edge)
 393 {
 394   return ((unsigned) edge->uid < VEC_length (ipa_edge_args_t,
 395                                              ipa_edge_args_vector));
 396 }
 397
 398 /* A function list element.  It is used to create a temporary worklist used in
 399    the propagation stage of IPCP. (can be used for more IPA optimizations)  */
 400 struct ipa_func_list
 401 {
 402   struct cgraph_node *node;
 403   struct ipa_func_list *next;
 404 };
 405
 406 /* ipa_func_list interface.  */
 407 struct ipa_func_list *ipa_init_func_list (void);
 408 void ipa_push_func_to_list_1 (struct ipa_func_list **, struct cgraph_node *,
 409                               struct ipa_node_params *);
 410 struct cgraph_node *ipa_pop_func_from_list (struct ipa_func_list **);
 411
 412 /* Add cgraph NODE to the worklist WL if it is not already in one.  */
 413
 414 static inline void
 415 ipa_push_func_to_list (struct ipa_func_list **wl, struct cgraph_node *node)
 416 {
 417   struct ipa_node_params *info = IPA_NODE_REF (node);
 418
 419   if (!info->node_enqueued)
 420     ipa_push_func_to_list_1 (wl, node, info);
 421 }
 422
 423 /* Callsite related calculations.  */
 424 void ipa_compute_jump_functions (struct cgraph_edge *);
 425 void ipa_count_arguments (struct cgraph_edge *);
 426
 427 /* Function formal parameters related computations.  */
 428 void ipa_initialize_node_params (struct cgraph_node *node);
 429 void ipa_detect_param_modifications (struct cgraph_node *);
 430 void ipa_analyze_params_uses (struct cgraph_node *);
 431 bool ipa_propagate_indirect_call_infos (struct cgraph_edge *cs,
 432                                         VEC (cgraph_edge_p, heap) **new_edges);
 433
 434 /* Debugging interface.  */
 435 void ipa_print_node_params (FILE *, struct cgraph_node *node);
 436 void ipa_print_all_params (FILE *);
 437 void ipa_print_node_jump_functions (FILE *f, struct cgraph_node *node);
 438 void ipa_print_all_jump_functions (FILE * f);
 439
 440 /* Structure to describe transformations of formal parameters and actual
 441    arguments.  Each instance describes one new parameter and they are meant to
 442    be stored in a vector.  Additionally, most users will probably want to store
 443    adjustments about parameters that are being removed altogether so that SSA
 444    names belonging to them can be replaced by SSA names of an artificial
 445    variable.  */
 446 struct ipa_parm_adjustment
 447 {
 448   /* The original PARM_DECL itself, helpful for processing of the body of the
 449      function itself.  Intended for traversing function bodies.
 450      ipa_modify_formal_parameters, ipa_modify_call_arguments and
 451      ipa_combine_adjustments ignore this and use base_index.
 452      ipa_modify_formal_parameters actually sets this.  */
 453   tree base;
 454
 455   /* Type of the new parameter.  However, if by_ref is true, the real type will
 456      be a pointer to this type.  */
 457   tree type;
 458
 459   /* The new declaration when creating/replacing a parameter.  Created by
 460      ipa_modify_formal_parameters, useful for functions modifying the body
 461      accordingly. */
 462   tree reduction;
 463
 464   /* New declaration of a substitute variable that we may use to replace all
 465      non-default-def ssa names when a parm decl is going away.  */
 466   tree new_ssa_base;
 467
 468   /* If non-NULL and the original parameter is to be removed (copy_param below
 469      is NULL), this is going to be its nonlocalized vars value.  */
 470   tree nonlocal_value;
 471
 472   /* Offset into the original parameter (for the cases when the new parameter
 473      is a component of an original one).  */
 474   HOST_WIDE_INT offset;
 475
 476   /* Zero based index of the original parameter this one is based on.  (ATM
 477      there is no way to insert a new parameter out of the blue because there is
 478      no need but if it arises the code can be easily exteded to do so.)  */
 479   int base_index;
 480
 481   /* This new parameter is an unmodified parameter at index base_index. */
 482   unsigned copy_param : 1;
 483
 484   /* This adjustment describes a parameter that is about to be removed
 485      completely.  Most users will probably need to book keep those so that they
 486      don't leave behinfd any non default def ssa names belonging to them.  */
 487   unsigned remove_param : 1;
 488
 489   /* The parameter is to be passed by reference.  */
 490   unsigned by_ref : 1;
 491 };
 492
 493 typedef struct ipa_parm_adjustment ipa_parm_adjustment_t;
 494 DEF_VEC_O (ipa_parm_adjustment_t);
 495 DEF_VEC_ALLOC_O (ipa_parm_adjustment_t, heap);
 496
 497 typedef VEC (ipa_parm_adjustment_t, heap) *ipa_parm_adjustment_vec;
 498
 499 VEC(tree, heap) *ipa_get_vector_of_formal_parms (tree fndecl);
 500 void ipa_modify_formal_parameters (tree fndecl, ipa_parm_adjustment_vec,
 501                                    const char *);
 502 void ipa_modify_call_arguments (struct cgraph_edge *, gimple,
 503                                 ipa_parm_adjustment_vec);
 504 ipa_parm_adjustment_vec ipa_combine_adjustments (ipa_parm_adjustment_vec,
 505                                                  ipa_parm_adjustment_vec);
 506 void ipa_dump_param_adjustments (FILE *, ipa_parm_adjustment_vec, tree);
 507
 508 void ipa_prop_write_jump_functions (cgraph_node_set set);
 509 void ipa_prop_read_jump_functions (void);
 510 void ipa_update_after_lto_read (void);
 511
 512 /* From tree-sra.c:  */
 513 bool build_ref_for_offset (tree *, tree, HOST_WIDE_INT, tree, bool);
 514
 515 #endif /* IPA_PROP_H */