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   /* Expected number of executions: calculated in profile.c.  */
 143   gcov_type count;
 144   /* Linked list's next */
 145   struct ipa_param_call_note *next;
 146   /* Statement that contains the call to the parameter above.  */
 147   gimple stmt;
 148   /* When in LTO, we the above stmt will be NULL and we need an uid. */
 149   unsigned int lto_stmt_uid;
 150   /* Index of the parameter that is called.  */
 151   int formal_id;
 152   /* Expected frequency of executions within the function. see cgraph_edge in
 153      cgraph.h for more on this. */
 154   int frequency;
 155   /* Depth of loop nest, 1 means no loop nest.  */
 156   unsigned short int loop_nest;
 157   /* Set when we have already found the target to be a compile time constant
 158      and turned this into an edge or when the note was found unusable for some
 159      reason.  */
 160   bool processed;
 161 };
 162
 163 /* Structure describing a single formal parameter.  */
 164 struct ipa_param_descriptor
 165 {
 166   /* IPA-CP lattice.  */
 167   struct ipcp_lattice ipcp_lattice;
 168   /* PARAM_DECL of this parameter.  */
 169   tree decl;
 170   /* Whether the value parameter has been modified within the function.  */
 171   unsigned modified : 1;
 172   /* Whether the parameter has been used as a call destination. */
 173   unsigned called : 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,
 182      this function's parameters would not be analyzed by the different
 183      stages of IPA CP.  */
 184   int param_count;
 185   /* Pointer to an array of structures describing individual formal
 186      parameters.  */
 187   struct ipa_param_descriptor *params;
 188   /* List of structures enumerating calls to a formal parameter.  */
 189   struct ipa_param_call_note *param_calls;
 190   /* Only for versioned nodes this field would not be NULL,
 191      it points to the node that IPA cp cloned from.  */
 192   struct cgraph_node *ipcp_orig_node;
 193   /* Meaningful only for original functions.  Expresses the
 194      ratio between the direct calls and sum of all invocations of
 195      this function (given by profiling info).  It is used to calculate
 196      the profiling information of the original function and the versioned
 197      one.  */
 198   gcov_type count_scale;
 199
 200   /* Whether this function is called with variable number of actual
 201      arguments.  */
 202   unsigned called_with_var_arguments : 1;
 203   /* Whether the modification analysis has already been performed. */
 204   unsigned modification_analysis_done : 1;
 205   /* Whether the param uses analysis has already been performed.  */
 206   unsigned uses_analysis_done : 1;
 207   /* Whether the function is enqueued in an ipa_func_list.  */
 208   unsigned node_enqueued : 1;
 209 };
 210
 211 /* ipa_node_params access functions.  Please use these to access fields that
 212    are or will be shared among various passes.  */
 213
 214 /* Set the number of formal parameters. */
 215
 216 static inline void
 217 ipa_set_param_count (struct ipa_node_params *info, int count)
 218 {
 219   info->param_count = count;
 220 }
 221
 222 /* Return the number of formal parameters. */
 223
 224 static inline int
 225 ipa_get_param_count (struct ipa_node_params *info)
 226 {
 227   return info->param_count;
 228 }
 229
 230 /* Return the declaration of Ith formal parameter of the function corresponding
 231    to INFO.  Note there is no setter function as this array is built just once
 232    using ipa_initialize_node_params. */
 233
 234 static inline tree
 235 ipa_get_param (struct ipa_node_params *info, int i)
 236 {
 237   return info->params[i].decl;
 238 }
 239
 240 /* Return the modification flag corresponding to the Ith formal parameter of
 241    the function associated with INFO.  Note that there is no setter method as
 242    the goal is to set all flags when building the array in
 243    ipa_detect_param_modifications.  */
 244
 245 static inline bool
 246 ipa_is_param_modified (struct ipa_node_params *info, int i)
 247 {
 248   return info->params[i].modified;
 249 }
 250
 251 /* Return the called flag corresponding to the Ith formal parameter of the
 252    function associated with INFO.  Note that there is no setter method as the
 253    goal is to set all flags when building the array in
 254    ipa_detect_called_params.  */
 255
 256 static inline bool
 257 ipa_is_param_called (struct ipa_node_params *info, int i)
 258 {
 259   return info->params[i].called;
 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
 281    its arguments. It is pointed to by a field in the
 282    callsite's corresponding cgraph_edge.  */
 283 typedef struct GTY(()) ipa_edge_args
 284 {
 285   /* Number of actual arguments in this callsite.  When set to 0,
 286      this callsite's parameters would not be analyzed by the different
 287      stages of IPA CP.  */
 288   int argument_count;
 289   /* Array of the callsite's jump function of each parameter.  */
 290   struct ipa_jump_func GTY ((length ("%h.argument_count"))) *jump_functions;
 291 } ipa_edge_args_t;
 292
 293 /* ipa_edge_args access functions.  Please use these to access fields that
 294    are or will be shared among various passes.  */
 295
 296 /* Set the number of actual arguments. */
 297
 298 static inline void
 299 ipa_set_cs_argument_count (struct ipa_edge_args *args, int count)
 300 {
 301   args->argument_count = count;
 302 }
 303
 304 /* Return the number of actual arguments. */
 305
 306 static inline int
 307 ipa_get_cs_argument_count (struct ipa_edge_args *args)
 308 {
 309   return args->argument_count;
 310 }
 311
 312 /* Returns a pointer to the jump function for the ith argument.  Please note
 313    there is no setter function as jump functions are all set up in
 314    ipa_compute_jump_functions. */
 315
 316 static inline struct ipa_jump_func *
 317 ipa_get_ith_jump_func (struct ipa_edge_args *args, int i)
 318 {
 319   return &args->jump_functions[i];
 320 }
 321
 322 /* Vectors need to have typedefs of structures.  */
 323 typedef struct ipa_node_params ipa_node_params_t;
 324
 325 /* Types of vectors holding the infos.  */
 326 DEF_VEC_O (ipa_node_params_t);
 327 DEF_VEC_ALLOC_O (ipa_node_params_t, heap);
 328 DEF_VEC_O (ipa_edge_args_t);
 329 DEF_VEC_ALLOC_O (ipa_edge_args_t, gc);
 330
 331 /* Vector where the parameter infos are actually stored. */
 332 extern VEC (ipa_node_params_t, heap) *ipa_node_params_vector;
 333 /* Vector where the parameter infos are actually stored. */
 334 extern GTY(()) VEC (ipa_edge_args_t, gc) *ipa_edge_args_vector;
 335
 336 /* Return the associated parameter/argument info corresponding to the given
 337    node/edge.  */
 338 #define IPA_NODE_REF(NODE) (VEC_index (ipa_node_params_t, \
 339                                        ipa_node_params_vector, (NODE)->uid))
 340 #define IPA_EDGE_REF(EDGE) (VEC_index (ipa_edge_args_t, \
 341                                        ipa_edge_args_vector, (EDGE)->uid))
 342 /* This macro checks validity of index returned by
 343    ipa_get_param_decl_index function.  */
 344 #define IS_VALID_JUMP_FUNC_INDEX(I) ((I) != -1)
 345
 346 /* Creating and freeing ipa_node_params and ipa_edge_args.  */
 347 void ipa_create_all_node_params (void);
 348 void ipa_create_all_edge_args (void);
 349 void ipa_free_edge_args_substructures (struct ipa_edge_args *);
 350 void ipa_free_node_params_substructures (struct ipa_node_params *);
 351 void ipa_free_all_node_params (void);
 352 void ipa_free_all_edge_args (void);
 353 void free_all_ipa_structures_after_ipa_cp (void);
 354 void free_all_ipa_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 /* Callsite related calculations.  */
 426 void ipa_compute_jump_functions (struct cgraph_edge *);
 427 void ipa_count_arguments (struct cgraph_edge *);
 428
 429 /* Function formal parameters related computations.  */
 430 void ipa_initialize_node_params (struct cgraph_node *node);
 431 void ipa_detect_param_modifications (struct cgraph_node *);
 432 void ipa_analyze_params_uses (struct cgraph_node *);
 433 bool ipa_propagate_indirect_call_infos (struct cgraph_edge *cs,
 434                                         VEC (cgraph_edge_p, heap) **new_edges);
 435
 436 /* Debugging interface.  */
 437 void ipa_print_node_params (FILE *, struct cgraph_node *node);
 438 void ipa_print_all_params (FILE *);
 439 void ipa_print_node_jump_functions (FILE *f, struct cgraph_node *node);
 440 void ipa_print_all_jump_functions (FILE * f);
 441
 442 /* Structure to describe transformations of formal parameters and actual
 443    arguments.  Each instance describes one new parameter and they are meant to
 444    be stored in a vector.  Additionally, most users will probably want to store
 445    adjustments about parameters that are being removed altogether so that SSA
 446    names belonging to them can be replaced by SSA names of an artificial
 447    variable.  */
 448 struct ipa_parm_adjustment
 449 {
 450   /* The original PARM_DECL itself, helpful for processing of the body of the
 451      function itself.  Intended for traversing function bodies.
 452      ipa_modify_formal_parameters, ipa_modify_call_arguments and
 453      ipa_combine_adjustments ignore this and use base_index.
 454      ipa_modify_formal_parameters actually sets this.  */
 455   tree base;
 456
 457   /* Type of the new parameter.  However, if by_ref is true, the real type will
 458      be a pointer to this type.  */
 459   tree type;
 460
 461   /* The new declaration when creating/replacing a parameter.  Created by
 462      ipa_modify_formal_parameters, useful for functions modifying the body
 463      accordingly. */
 464   tree reduction;
 465
 466   /* New declaration of a substitute variable that we may use to replace all
 467      non-default-def ssa names when a parm decl is going away.  */
 468   tree new_ssa_base;
 469
 470   /* If non-NULL and the original parameter is to be removed (copy_param below
 471      is NULL), this is going to be its nonlocalized vars value.  */
 472   tree nonlocal_value;
 473
 474   /* Offset into the original parameter (for the cases when the new parameter
 475      is a component of an original one).  */
 476   HOST_WIDE_INT offset;
 477
 478   /* Zero based index of the original parameter this one is based on.  (ATM
 479      there is no way to insert a new parameter out of the blue because there is
 480      no need but if it arises the code can be easily exteded to do so.)  */
 481   int base_index;
 482
 483   /* This new parameter is an unmodified parameter at index base_index. */
 484   unsigned copy_param : 1;
 485
 486   /* This adjustment describes a parameter that is about to be removed
 487      completely.  Most users will probably need to book keep those so that they
 488      don't leave behinfd any non default def ssa names belonging to them.  */
 489   unsigned remove_param : 1;
 490
 491   /* The parameter is to be passed by reference.  */
 492   unsigned by_ref : 1;
 493 };
 494
 495 typedef struct ipa_parm_adjustment ipa_parm_adjustment_t;
 496 DEF_VEC_O (ipa_parm_adjustment_t);
 497 DEF_VEC_ALLOC_O (ipa_parm_adjustment_t, heap);
 498
 499 typedef VEC (ipa_parm_adjustment_t, heap) *ipa_parm_adjustment_vec;
 500
 501 VEC(tree, heap) *ipa_get_vector_of_formal_parms (tree fndecl);
 502 void ipa_modify_formal_parameters (tree fndecl, ipa_parm_adjustment_vec,
 503                                    const char *);
 504 void ipa_modify_call_arguments (struct cgraph_edge *, gimple,
 505                                 ipa_parm_adjustment_vec);
 506 ipa_parm_adjustment_vec ipa_combine_adjustments (ipa_parm_adjustment_vec,
 507                                                  ipa_parm_adjustment_vec);
 508 void ipa_dump_param_adjustments (FILE *, ipa_parm_adjustment_vec, tree);
 509
 510 void ipa_prop_write_jump_functions (cgraph_node_set set);
 511 void ipa_prop_read_jump_functions (void);
 512 void ipa_update_after_lto_read (void);
 513 void lto_ipa_fixup_call_notes (struct cgraph_node *, gimple *);
 514
 515 /* From tree-sra.c:  */
 516 bool build_ref_for_offset (tree *, tree, HOST_WIDE_INT, tree, bool);
 517
 518 #endif /* IPA_PROP_H */