gcc/ipa-prop.h

   1 /* Interprocedural analyses.
   2    Copyright (C) 2005, 2007, 2008, 2009
   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
  28 /* The following definitions and interfaces are used by
  29    interprocedural analyses or parameters.  */
  30
  31 /* ipa-prop.c stuff (ipa-cp, indirect inlining):  */
  32
  33 /* A jump function for a callsite represents the values passed as actual
  34    arguments of the callsite. There are three main types of values :
  35
  36    Pass-through - the caller's formal parameter is passed as an actual
  37                   argument, possibly one simple operation performed on it.
  38    Constant     - a constant (is_gimple_ip_invariant)is passed as an actual
  39                   argument.
  40    Unknown      - neither of the above.
  41
  42    IPA_JF_CONST_MEMBER_PTR stands for C++ member pointers, it is a special
  43    constant in this regard.  Other constants are represented with IPA_JF_CONST.
  44
  45    IPA_JF_ANCESTOR is a special pass-through jump function, which means that
  46    the result is an address of a part of the object pointed to by the formal
  47    parameter to which the function refers.  It is mainly intended to represent
  48    getting addresses of of ancestor fields in C++
  49    (e.g. &this_1(D)->D.1766.D.1756).  Note that if the original pointer is
  50    NULL, ancestor jump function must behave like a simple pass-through.
  51
  52    Other pass-through functions can either simply pass on an unchanged formal
  53    parameter or can apply one simple binary operation to it (such jump
  54    functions are called polynomial).
  55
  56    IPA_JF_KNOWN_TYPE is a special type of an "unknown" function that applies
  57    only to pointer parameters.  It means that even though we cannot prove that
  58    the passed value is an interprocedural constant, we still know the exact
  59    type of the containing object which may be valuable for devirtualization.
  60
  61    Jump functions are computed in ipa-prop.c by function
  62    update_call_notes_after_inlining.  Some information can be lost and jump
  63    functions degraded accordingly when inlining, see
  64    update_call_notes_after_inlining in the same file.  */
  65
  66 enum jump_func_type
  67 {
  68   IPA_JF_UNKNOWN = 0,  /* newly allocated and zeroed jump functions default */
  69   IPA_JF_KNOWN_TYPE,        /* represented by field base_binfo */
  70   IPA_JF_CONST,             /* represented by field costant */
  71   IPA_JF_CONST_MEMBER_PTR,  /* represented by field member_cst */
  72   IPA_JF_PASS_THROUGH,      /* represented by field pass_through */
  73   IPA_JF_ANCESTOR           /* represented by field ancestor */
  74 };
  75
  76 /* Structure holding data required to describe a pass-through jump function.  */
  77
  78 struct GTY(()) ipa_pass_through_data
  79 {
  80   /* If an operation is to be performed on the original parameter, this is the
  81      second (constant) operand.  */
  82   tree operand;
  83   /* Number of the caller's formal parameter being passed.  */
  84   int formal_id;
  85   /* Operation that is performed on the argument before it is passed on.
  86      NOP_EXPR means no operation.  Otherwise oper must be a simple binary
  87      arithmetic operation where the caller's parameter is the first operand and
  88      operand field from this structure is the second one.  */
  89   enum tree_code operation;
  90 };
  91
  92 /* Structure holding data required to describe an ancestor pass-through
  93    jump function.  */
  94
  95 struct GTY(()) ipa_ancestor_jf_data
  96 {
  97   /* Offset of the field representing the ancestor.  */
  98   HOST_WIDE_INT offset;
  99   /* TYpe of the result.  */
 100   tree type;
 101   /* Number of the caller's formal parameter being passed.  */
 102   int formal_id;
 103 };
 104
 105 /* Structure holding a C++ member pointer constant.  Holds a pointer to the
 106    method and delta offset.  */
 107 struct GTY(()) ipa_member_ptr_cst
 108 {
 109   tree pfn;
 110   tree delta;
 111 };
 112
 113 /* A jump function for a callsite represents the values passed as actual
 114    arguments of the callsite. See enum jump_func_type for the various
 115    types of jump functions supported.  */
 116 struct GTY (()) ipa_jump_func
 117 {
 118   enum jump_func_type type;
 119   /* Represents a value of a jump function.  pass_through is used only in jump
 120      function context.  constant represents the actual constant in constant jump
 121      functions and member_cst holds constant c++ member functions.  */
 122   union jump_func_value
 123   {
 124     tree GTY ((tag ("IPA_JF_KNOWN_TYPE"))) base_binfo;
 125     tree GTY ((tag ("IPA_JF_CONST"))) constant;
 126     struct ipa_member_ptr_cst GTY ((tag ("IPA_JF_CONST_MEMBER_PTR"))) member_cst;
 127     struct ipa_pass_through_data GTY ((tag ("IPA_JF_PASS_THROUGH"))) pass_through;
 128     struct ipa_ancestor_jf_data GTY ((tag ("IPA_JF_ANCESTOR"))) ancestor;
 129   } GTY ((desc ("%1.type"))) value;
 130 };
 131
 132 /* All formal parameters in the program have a lattice associated with it
 133    computed by the interprocedural stage of IPCP.
 134    There are three main values of the lattice:
 135    IPA_TOP - unknown,
 136    IPA_BOTTOM - non constant,
 137    IPA_CONST_VALUE - simple scalar constant,
 138    Cval of formal f will have a constant value if all callsites to this
 139    function have the same constant value passed to f.
 140    Integer and real constants are represented as IPA_CONST_VALUE.  */
 141 enum ipa_lattice_type
 142 {
 143   IPA_BOTTOM,
 144   IPA_CONST_VALUE,
 145   IPA_TOP
 146 };
 147
 148 /* All formal parameters in the program have a cval computed by
 149    the interprocedural stage of IPCP. See enum ipa_lattice_type for
 150    the various types of lattices supported */
 151 struct ipcp_lattice
 152 {
 153   enum ipa_lattice_type type;
 154   tree constant;
 155 };
 156
 157 /* Structure describing a single formal parameter.  */
 158 struct ipa_param_descriptor
 159 {
 160   /* IPA-CP lattice.  */
 161   struct ipcp_lattice ipcp_lattice;
 162   /* PARAM_DECL of this parameter.  */
 163   tree decl;
 164   /* Whether the value parameter has been modified within the function.  */
 165   unsigned modified : 1;
 166   /* The parameter is used.  */
 167   unsigned used : 1;
 168 };
 169
 170 /* ipa_node_params stores information related to formal parameters of functions
 171    and some other information for interprocedural passes that operate on
 172    parameters (such as ipa-cp).  */
 173 struct ipa_node_params
 174 {
 175   /* Number of formal parameters of this function.  When set to 0,
 176      this function's parameters would not be analyzed by the different
 177      stages of IPA CP.  */
 178   int param_count;
 179   /* Whether this function is called with variable number of actual
 180      arguments.  */
 181   unsigned called_with_var_arguments : 1;
 182   /* Whether the modification analysis has already been performed. */
 183   unsigned modification_analysis_done : 1;
 184   /* Whether the param uses analysis has already been performed.  */
 185   unsigned uses_analysis_done : 1;
 186   /* Whether the function is enqueued in an ipa_func_list.  */
 187   unsigned node_enqueued : 1;
 188   /* Pointer to an array of structures describing individual formal
 189      parameters.  */
 190   struct ipa_param_descriptor *params;
 191   /* Only for versioned nodes this field would not be NULL,
 192      it points to the node that IPA cp cloned from.  */
 193   struct cgraph_node *ipcp_orig_node;
 194   /* Meaningful only for original functions.  Expresses the
 195      ratio between the direct calls and sum of all invocations of
 196      this function (given by profiling info).  It is used to calculate
 197      the profiling information of the original function and the versioned
 198      one.  */
 199   gcov_type count_scale;
 200 };
 201
 202 /* ipa_node_params access functions.  Please use these to access fields that
 203    are or will be shared among various passes.  */
 204
 205 /* Set the number of formal parameters. */
 206
 207 static inline void
 208 ipa_set_param_count (struct ipa_node_params *info, int count)
 209 {
 210   info->param_count = count;
 211 }
 212
 213 /* Return the number of formal parameters. */
 214
 215 static inline int
 216 ipa_get_param_count (struct ipa_node_params *info)
 217 {
 218   return info->param_count;
 219 }
 220
 221 /* Return the declaration of Ith formal parameter of the function corresponding
 222    to INFO.  Note there is no setter function as this array is built just once
 223    using ipa_initialize_node_params. */
 224
 225 static inline tree
 226 ipa_get_param (struct ipa_node_params *info, int i)
 227 {
 228   return info->params[i].decl;
 229 }
 230
 231 /* Return the modification flag corresponding to the Ith formal parameter of
 232    the function associated with INFO.  Note that there is no setter method as
 233    the goal is to set all flags when building the array in
 234    ipa_detect_param_modifications.  */
 235
 236 static inline bool
 237 ipa_is_param_modified (struct ipa_node_params *info, int i)
 238 {
 239   return info->params[i].modified;
 240 }
 241
 242 /* Return the used flag corresponding to the Ith formal parameter of
 243    the function associated with INFO.  */
 244
 245 static inline bool
 246 ipa_is_param_used (struct ipa_node_params *info, int i)
 247 {
 248   return info->params[i].used;
 249 }
 250
 251 /* Flag this node as having callers with variable number of arguments.  */
 252
 253 static inline void
 254 ipa_set_called_with_variable_arg (struct ipa_node_params *info)
 255 {
 256   info->called_with_var_arguments = 1;
 257 }
 258
 259 /* Have we detected this node was called with variable number of arguments? */
 260
 261 static inline bool
 262 ipa_is_called_with_var_arguments (struct ipa_node_params *info)
 263 {
 264   return info->called_with_var_arguments;
 265 }
 266
 267
 268
 269 /* ipa_edge_args stores information related to a callsite and particularly
 270    its arguments. It is pointed to by a field in the
 271    callsite's corresponding cgraph_edge.  */
 272 typedef struct GTY(()) ipa_edge_args
 273 {
 274   /* Number of actual arguments in this callsite.  When set to 0,
 275      this callsite's parameters would not be analyzed by the different
 276      stages of IPA CP.  */
 277   int argument_count;
 278   /* Array of the callsite's jump function of each parameter.  */
 279   struct ipa_jump_func GTY ((length ("%h.argument_count"))) *jump_functions;
 280 } ipa_edge_args_t;
 281
 282 /* ipa_edge_args access functions.  Please use these to access fields that
 283    are or will be shared among various passes.  */
 284
 285 /* Set the number of actual arguments. */
 286
 287 static inline void
 288 ipa_set_cs_argument_count (struct ipa_edge_args *args, int count)
 289 {
 290   args->argument_count = count;
 291 }
 292
 293 /* Return the number of actual arguments. */
 294
 295 static inline int
 296 ipa_get_cs_argument_count (struct ipa_edge_args *args)
 297 {
 298   return args->argument_count;
 299 }
 300
 301 /* Returns a pointer to the jump function for the ith argument.  Please note
 302    there is no setter function as jump functions are all set up in
 303    ipa_compute_jump_functions. */
 304
 305 static inline struct ipa_jump_func *
 306 ipa_get_ith_jump_func (struct ipa_edge_args *args, int i)
 307 {
 308   return &args->jump_functions[i];
 309 }
 310
 311 /* Vectors need to have typedefs of structures.  */
 312 typedef struct ipa_node_params ipa_node_params_t;
 313
 314 /* Types of vectors holding the infos.  */
 315 DEF_VEC_O (ipa_node_params_t);
 316 DEF_VEC_ALLOC_O (ipa_node_params_t, heap);
 317 DEF_VEC_O (ipa_edge_args_t);
 318 DEF_VEC_ALLOC_O (ipa_edge_args_t, gc);
 319
 320 /* Vector where the parameter infos are actually stored. */
 321 extern VEC (ipa_node_params_t, heap) *ipa_node_params_vector;
 322 /* Vector where the parameter infos are actually stored. */
 323 extern GTY(()) VEC (ipa_edge_args_t, gc) *ipa_edge_args_vector;
 324
 325 /* Return the associated parameter/argument info corresponding to the given
 326    node/edge.  */
 327 #define IPA_NODE_REF(NODE) (VEC_index (ipa_node_params_t, \
 328                                        ipa_node_params_vector, (NODE)->uid))
 329 #define IPA_EDGE_REF(EDGE) (VEC_index (ipa_edge_args_t, \
 330                                        ipa_edge_args_vector, (EDGE)->uid))
 331 /* This macro checks validity of index returned by
 332    ipa_get_param_decl_index function.  */
 333 #define IS_VALID_JUMP_FUNC_INDEX(I) ((I) != -1)
 334
 335 /* Creating and freeing ipa_node_params and ipa_edge_args.  */
 336 void ipa_create_all_node_params (void);
 337 void ipa_create_all_edge_args (void);
 338 void ipa_free_edge_args_substructures (struct ipa_edge_args *);
 339 void ipa_free_node_params_substructures (struct ipa_node_params *);
 340 void ipa_free_all_node_params (void);
 341 void ipa_free_all_edge_args (void);
 342 void ipa_create_all_structures_for_iinln (void);
 343 void ipa_free_all_structures_after_ipa_cp (void);
 344 void ipa_free_all_structures_after_iinln (void);
 345 void ipa_register_cgraph_hooks (void);
 346
 347 /* This function ensures the array of node param infos is big enough to
 348    accommodate a structure for all nodes and reallocates it if not.  */
 349
 350 static inline void
 351 ipa_check_create_node_params (void)
 352 {
 353   if (!ipa_node_params_vector)
 354     ipa_node_params_vector = VEC_alloc (ipa_node_params_t, heap,
 355                                         cgraph_max_uid);
 356
 357   if (VEC_length (ipa_node_params_t, ipa_node_params_vector)
 358       <= (unsigned) cgraph_max_uid)
 359     VEC_safe_grow_cleared (ipa_node_params_t, heap,
 360                            ipa_node_params_vector, cgraph_max_uid + 1);
 361 }
 362
 363 /* This function ensures the array of edge arguments infos is big enough to
 364    accommodate a structure for all edges and reallocates it if not.  */
 365
 366 static inline void
 367 ipa_check_create_edge_args (void)
 368 {
 369   if (!ipa_edge_args_vector)
 370     ipa_edge_args_vector = VEC_alloc (ipa_edge_args_t, gc,
 371                                       cgraph_edge_max_uid);
 372
 373   if (VEC_length (ipa_edge_args_t, ipa_edge_args_vector)
 374       <=  (unsigned) cgraph_edge_max_uid)
 375     VEC_safe_grow_cleared (ipa_edge_args_t, gc, ipa_edge_args_vector,
 376                            cgraph_edge_max_uid + 1);
 377 }
 378
 379 /* Returns true if the array of edge infos is large enough to accommodate an
 380    info for EDGE.  The main purpose of this function is that debug dumping
 381    function can check info availability without causing reallocations.  */
 382
 383 static inline bool
 384 ipa_edge_args_info_available_for_edge_p (struct cgraph_edge *edge)
 385 {
 386   return ((unsigned) edge->uid < VEC_length (ipa_edge_args_t,
 387                                              ipa_edge_args_vector));
 388 }
 389
 390 /* A function list element.  It is used to create a temporary worklist used in
 391    the propagation stage of IPCP. (can be used for more IPA optimizations)  */
 392 struct ipa_func_list
 393 {
 394   struct cgraph_node *node;
 395   struct ipa_func_list *next;
 396 };
 397
 398 /* ipa_func_list interface.  */
 399 struct ipa_func_list *ipa_init_func_list (void);
 400 void ipa_push_func_to_list_1 (struct ipa_func_list **, struct cgraph_node *,
 401                               struct ipa_node_params *);
 402 struct cgraph_node *ipa_pop_func_from_list (struct ipa_func_list **);
 403
 404 /* Add cgraph NODE to the worklist WL if it is not already in one.  */
 405
 406 static inline void
 407 ipa_push_func_to_list (struct ipa_func_list **wl, struct cgraph_node *node)
 408 {
 409   struct ipa_node_params *info = IPA_NODE_REF (node);
 410
 411   if (!info->node_enqueued)
 412     ipa_push_func_to_list_1 (wl, node, info);
 413 }
 414
 415 /* Callsite related calculations.  */
 416 void ipa_compute_jump_functions (struct cgraph_node *);
 417 void ipa_count_arguments (struct cgraph_edge *);
 418
 419 /* Function formal parameters related computations.  */
 420 void ipa_initialize_node_params (struct cgraph_node *node);
 421 void ipa_detect_param_modifications (struct cgraph_node *);
 422 void ipa_analyze_params_uses (struct cgraph_node *);
 423 bool ipa_propagate_indirect_call_infos (struct cgraph_edge *cs,
 424                                         VEC (cgraph_edge_p, heap) **new_edges);
 425
 426 /* Debugging interface.  */
 427 void ipa_print_node_params (FILE *, struct cgraph_node *node);
 428 void ipa_print_all_params (FILE *);
 429 void ipa_print_node_jump_functions (FILE *f, struct cgraph_node *node);
 430 void ipa_print_all_jump_functions (FILE * f);
 431
 432 /* Structure to describe transformations of formal parameters and actual
 433    arguments.  Each instance describes one new parameter and they are meant to
 434    be stored in a vector.  Additionally, most users will probably want to store
 435    adjustments about parameters that are being removed altogether so that SSA
 436    names belonging to them can be replaced by SSA names of an artificial
 437    variable.  */
 438 struct ipa_parm_adjustment
 439 {
 440   /* The original PARM_DECL itself, helpful for processing of the body of the
 441      function itself.  Intended for traversing function bodies.
 442      ipa_modify_formal_parameters, ipa_modify_call_arguments and
 443      ipa_combine_adjustments ignore this and use base_index.
 444      ipa_modify_formal_parameters actually sets this.  */
 445   tree base;
 446
 447   /* Type of the new parameter.  However, if by_ref is true, the real type will
 448      be a pointer to this type.  */
 449   tree type;
 450
 451   /* The new declaration when creating/replacing a parameter.  Created by
 452      ipa_modify_formal_parameters, useful for functions modifying the body
 453      accordingly. */
 454   tree reduction;
 455
 456   /* New declaration of a substitute variable that we may use to replace all
 457      non-default-def ssa names when a parm decl is going away.  */
 458   tree new_ssa_base;
 459
 460   /* If non-NULL and the original parameter is to be removed (copy_param below
 461      is NULL), this is going to be its nonlocalized vars value.  */
 462   tree nonlocal_value;
 463
 464   /* Offset into the original parameter (for the cases when the new parameter
 465      is a component of an original one).  */
 466   HOST_WIDE_INT offset;
 467
 468   /* Zero based index of the original parameter this one is based on.  (ATM
 469      there is no way to insert a new parameter out of the blue because there is
 470      no need but if it arises the code can be easily exteded to do so.)  */
 471   int base_index;
 472
 473   /* This new parameter is an unmodified parameter at index base_index. */
 474   unsigned copy_param : 1;
 475
 476   /* This adjustment describes a parameter that is about to be removed
 477      completely.  Most users will probably need to book keep those so that they
 478      don't leave behinfd any non default def ssa names belonging to them.  */
 479   unsigned remove_param : 1;
 480
 481   /* The parameter is to be passed by reference.  */
 482   unsigned by_ref : 1;
 483 };
 484
 485 typedef struct ipa_parm_adjustment ipa_parm_adjustment_t;
 486 DEF_VEC_O (ipa_parm_adjustment_t);
 487 DEF_VEC_ALLOC_O (ipa_parm_adjustment_t, heap);
 488
 489 typedef VEC (ipa_parm_adjustment_t, heap) *ipa_parm_adjustment_vec;
 490
 491 VEC(tree, heap) *ipa_get_vector_of_formal_parms (tree fndecl);
 492 void ipa_modify_formal_parameters (tree fndecl, ipa_parm_adjustment_vec,
 493                                    const char *);
 494 void ipa_modify_call_arguments (struct cgraph_edge *, gimple,
 495                                 ipa_parm_adjustment_vec);
 496 ipa_parm_adjustment_vec ipa_combine_adjustments (ipa_parm_adjustment_vec,
 497                                                  ipa_parm_adjustment_vec);
 498 void ipa_dump_param_adjustments (FILE *, ipa_parm_adjustment_vec, tree);
 499
 500 void ipa_prop_write_jump_functions (cgraph_node_set set);
 501 void ipa_prop_read_jump_functions (void);
 502 void ipa_update_after_lto_read (void);
 503
 504 /* From tree-sra.c:  */
 505 bool build_ref_for_offset (tree *, tree, HOST_WIDE_INT, tree, bool);
 506
 507 #endif /* IPA_PROP_H */