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