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 #include "alloc-pool.h"
  29
  30 /* The following definitions and interfaces are used by
  31    interprocedural analyses or parameters.  */
  32
  33 /* ipa-prop.c stuff (ipa-cp, indirect inlining):  */
  34
  35 /* A jump function for a callsite represents the values passed as actual
  36    arguments of the callsite.  They were originally proposed in a paper called
  37    "Interprocedural Constant Propagation", by David Callahan, Keith D Cooper,
  38    Ken Kennedy, Linda Torczon in Comp86, pg 152-161.  There are three main
  39    types of values :
  40
  41    Pass-through - the caller's formal parameter is passed as an actual
  42                   argument, possibly one simple operation performed on it.
  43    Constant     - a constant (is_gimple_ip_invariant)is passed as an actual
  44                   argument.
  45    Unknown      - neither of the above.
  46
  47    IPA_JF_CONST_MEMBER_PTR stands for C++ member pointers, it is a special
  48    constant in this regard because it is in fact a structure consisting of two
  49    values.  Other constants are represented with IPA_JF_CONST.
  50
  51    IPA_JF_ANCESTOR is a special pass-through jump function, which means that
  52    the result is an address of a part of the object pointed to by the formal
  53    parameter to which the function refers.  It is mainly intended to represent
  54    getting addresses of of ancestor fields in C++
  55    (e.g. &this_1(D)->D.1766.D.1756).  Note that if the original pointer is
  56    NULL, ancestor jump function must behave like a simple pass-through.
  57
  58    Other pass-through functions can either simply pass on an unchanged formal
  59    parameter or can apply one simple binary operation to it (such jump
  60    functions are called polynomial).
  61
  62    IPA_JF_KNOWN_TYPE is a special type of an "unknown" function that applies
  63    only to pointer parameters.  It means that even though we cannot prove that
  64    the passed value is an interprocedural constant, we still know the exact
  65    type of the containing object which may be valuable for devirtualization.
  66
  67    Jump functions are computed in ipa-prop.c by function
  68    update_call_notes_after_inlining.  Some information can be lost and jump
  69    functions degraded accordingly when inlining, see
  70    update_call_notes_after_inlining in the same file.  */
  71
  72 enum jump_func_type
  73 {
  74   IPA_JF_UNKNOWN = 0,  /* newly allocated and zeroed jump functions default */
  75   IPA_JF_KNOWN_TYPE,        /* represented by field known_type */
  76   IPA_JF_CONST,             /* represented by field costant */
  77   IPA_JF_CONST_MEMBER_PTR,  /* represented by field member_cst */
  78   IPA_JF_PASS_THROUGH,      /* represented by field pass_through */
  79   IPA_JF_ANCESTOR           /* represented by field ancestor */
  80 };
  81
  82 /* Structure holding data required to describe a known type jump function.  */
  83 struct GTY(()) ipa_known_type_data
  84 {
  85   /* Offset of the component of the base_type being described.  */
  86   HOST_WIDE_INT offset;
  87   /* Type of the whole object.  */
  88   tree base_type;
  89   /* Type of the component of the object that is being described.  */
  90   tree component_type;
  91 };
  92
  93 /* Structure holding data required to describe a pass-through jump function.  */
  94
  95 struct GTY(()) ipa_pass_through_data
  96 {
  97   /* If an operation is to be performed on the original parameter, this is the
  98      second (constant) operand.  */
  99   tree operand;
 100   /* Number of the caller's formal parameter being passed.  */
 101   int formal_id;
 102   /* Operation that is performed on the argument before it is passed on.
 103      NOP_EXPR means no operation.  Otherwise oper must be a simple binary
 104      arithmetic operation where the caller's parameter is the first operand and
 105      operand field from this structure is the second one.  */
 106   enum tree_code operation;
 107 };
 108
 109 /* Structure holding data required to describe an ancestor pass-through
 110    jump function.  */
 111
 112 struct GTY(()) ipa_ancestor_jf_data
 113 {
 114   /* Offset of the field representing the ancestor.  */
 115   HOST_WIDE_INT offset;
 116   /* TYpe of the result.  */
 117   tree type;
 118   /* Number of the caller's formal parameter being passed.  */
 119   int formal_id;
 120 };
 121
 122 /* Structure holding a C++ member pointer constant.  Holds a pointer to the
 123    method and delta offset.  */
 124 struct GTY(()) ipa_member_ptr_cst
 125 {
 126   tree pfn;
 127   tree delta;
 128 };
 129
 130 /* A jump function for a callsite represents the values passed as actual
 131    arguments of the callsite. See enum jump_func_type for the various
 132    types of jump functions supported.  */
 133 typedef struct GTY (()) ipa_jump_func
 134 {
 135   enum jump_func_type type;
 136   /* Represents a value of a jump function.  pass_through is used only in jump
 137      function context.  constant represents the actual constant in constant jump
 138      functions and member_cst holds constant c++ member functions.  */
 139   union jump_func_value
 140   {
 141     struct ipa_known_type_data GTY ((tag ("IPA_JF_KNOWN_TYPE"))) known_type;
 142     tree GTY ((tag ("IPA_JF_CONST"))) constant;
 143     struct ipa_member_ptr_cst GTY ((tag ("IPA_JF_CONST_MEMBER_PTR"))) member_cst;
 144     struct ipa_pass_through_data GTY ((tag ("IPA_JF_PASS_THROUGH"))) pass_through;
 145     struct ipa_ancestor_jf_data GTY ((tag ("IPA_JF_ANCESTOR"))) ancestor;
 146   } GTY ((desc ("%1.type"))) value;
 147 } ipa_jump_func_t;
 148
 149 DEF_VEC_O (ipa_jump_func_t);
 150 DEF_VEC_ALLOC_O (ipa_jump_func_t, gc);
 151
 152 /* Summary describing a single formal parameter.  */
 153
 154 struct ipa_param_descriptor
 155 {
 156   /* PARAM_DECL of this parameter.  */
 157   tree decl;
 158   /* The parameter is used.  */
 159   unsigned used : 1;
 160 };
 161
 162 typedef struct ipa_param_descriptor ipa_param_descriptor_t;
 163 DEF_VEC_O (ipa_param_descriptor_t);
 164 DEF_VEC_ALLOC_O (ipa_param_descriptor_t, heap);
 165 struct ipcp_lattice;
 166
 167 /* ipa_node_params stores information related to formal parameters of functions
 168    and some other information for interprocedural passes that operate on
 169    parameters (such as ipa-cp).  */
 170
 171 struct ipa_node_params
 172 {
 173   /* Information about individual formal parameters that are gathered when
 174      summaries are generated. */
 175   VEC (ipa_param_descriptor_t, heap) *descriptors;
 176   /* Pointer to an array of structures describing individual formal
 177      parameters.  */
 178   struct ipcp_lattice *lattices;
 179   /* Only for versioned nodes this field would not be NULL,
 180      it points to the node that IPA cp cloned from.  */
 181   struct cgraph_node *ipcp_orig_node;
 182   /* If this node is an ipa-cp clone, these are the known values that describe
 183      what it has been specialized for.  */
 184   VEC (tree, heap) *known_vals;
 185   /* Whether the param uses analysis has already been performed.  */
 186   unsigned uses_analysis_done : 1;
 187   /* Whether the function is enqueued in ipa-cp propagation stack.  */
 188   unsigned node_enqueued : 1;
 189   /* Whether we should create a specialized version based on values that are
 190      known to be constant in all contexts.  */
 191   unsigned clone_for_all_contexts : 1;
 192   /* Node has been completely replaced by clones and will be removed after
 193      ipa-cp is finished.  */
 194   unsigned node_dead : 1;
 195 };
 196
 197 /* ipa_node_params access functions.  Please use these to access fields that
 198    are or will be shared among various passes.  */
 199
 200 /* Return the number of formal parameters. */
 201
 202 static inline int
 203 ipa_get_param_count (struct ipa_node_params *info)
 204 {
 205   return VEC_length (ipa_param_descriptor_t, info->descriptors);
 206 }
 207
 208 /* Return the declaration of Ith formal parameter of the function corresponding
 209    to INFO.  Note there is no setter function as this array is built just once
 210    using ipa_initialize_node_params. */
 211
 212 static inline tree
 213 ipa_get_param (struct ipa_node_params *info, int i)
 214 {
 215   return VEC_index (ipa_param_descriptor_t, info->descriptors, i)->decl;
 216 }
 217
 218 /* Set the used flag corresponding to the Ith formal parameter of the function
 219    associated with INFO to VAL.  */
 220
 221 static inline void
 222 ipa_set_param_used (struct ipa_node_params *info, int i, bool val)
 223 {
 224   VEC_index (ipa_param_descriptor_t, info->descriptors, i)->used = val;
 225 }
 226
 227 /* Return the used flag corresponding to the Ith formal parameter of the
 228    function associated with INFO.  */
 229
 230 static inline bool
 231 ipa_is_param_used (struct ipa_node_params *info, int i)
 232 {
 233   return VEC_index (ipa_param_descriptor_t, info->descriptors, i)->used;
 234 }
 235
 236 /* ipa_edge_args stores information related to a callsite and particularly its
 237    arguments.  It can be accessed by the IPA_EDGE_REF macro.  */
 238 typedef struct GTY(()) ipa_edge_args
 239 {
 240   /* Vector of the callsite's jump function of each parameter.  */
 241   VEC (ipa_jump_func_t, gc) *jump_functions;
 242 } ipa_edge_args_t;
 243
 244 /* ipa_edge_args access functions.  Please use these to access fields that
 245    are or will be shared among various passes.  */
 246
 247 /* Return the number of actual arguments. */
 248
 249 static inline int
 250 ipa_get_cs_argument_count (struct ipa_edge_args *args)
 251 {
 252   return VEC_length (ipa_jump_func_t, args->jump_functions);
 253 }
 254
 255 /* Returns a pointer to the jump function for the ith argument.  Please note
 256    there is no setter function as jump functions are all set up in
 257    ipa_compute_jump_functions. */
 258
 259 static inline struct ipa_jump_func *
 260 ipa_get_ith_jump_func (struct ipa_edge_args *args, int i)
 261 {
 262   return VEC_index (ipa_jump_func_t, args->jump_functions, i);
 263 }
 264
 265 /* Vectors need to have typedefs of structures.  */
 266 typedef struct ipa_node_params ipa_node_params_t;
 267
 268 /* Types of vectors holding the infos.  */
 269 DEF_VEC_O (ipa_node_params_t);
 270 DEF_VEC_ALLOC_O (ipa_node_params_t, heap);
 271 DEF_VEC_O (ipa_edge_args_t);
 272 DEF_VEC_ALLOC_O (ipa_edge_args_t, gc);
 273
 274 /* Vector where the parameter infos are actually stored. */
 275 extern VEC (ipa_node_params_t, heap) *ipa_node_params_vector;
 276 /* Vector where the parameter infos are actually stored. */
 277 extern GTY(()) VEC (ipa_edge_args_t, gc) *ipa_edge_args_vector;
 278
 279 /* Return the associated parameter/argument info corresponding to the given
 280    node/edge.  */
 281 #define IPA_NODE_REF(NODE) (VEC_index (ipa_node_params_t, \
 282                                        ipa_node_params_vector, (NODE)->uid))
 283 #define IPA_EDGE_REF(EDGE) (VEC_index (ipa_edge_args_t, \
 284                                        ipa_edge_args_vector, (EDGE)->uid))
 285 /* This macro checks validity of index returned by
 286    ipa_get_param_decl_index function.  */
 287 #define IS_VALID_JUMP_FUNC_INDEX(I) ((I) != -1)
 288
 289 /* Creating and freeing ipa_node_params and ipa_edge_args.  */
 290 void ipa_create_all_node_params (void);
 291 void ipa_create_all_edge_args (void);
 292 void ipa_free_edge_args_substructures (struct ipa_edge_args *);
 293 void ipa_free_node_params_substructures (struct ipa_node_params *);
 294 void ipa_free_all_node_params (void);
 295 void ipa_free_all_edge_args (void);
 296 void ipa_free_all_structures_after_ipa_cp (void);
 297 void ipa_free_all_structures_after_iinln (void);
 298 void ipa_register_cgraph_hooks (void);
 299
 300 /* This function ensures the array of node param infos is big enough to
 301    accommodate a structure for all nodes and reallocates it if not.  */
 302
 303 static inline void
 304 ipa_check_create_node_params (void)
 305 {
 306   if (!ipa_node_params_vector)
 307     ipa_node_params_vector = VEC_alloc (ipa_node_params_t, heap,
 308                                         cgraph_max_uid);
 309
 310   if (VEC_length (ipa_node_params_t, ipa_node_params_vector)
 311       <= (unsigned) cgraph_max_uid)
 312     VEC_safe_grow_cleared (ipa_node_params_t, heap,
 313                            ipa_node_params_vector, cgraph_max_uid + 1);
 314 }
 315
 316 /* This function ensures the array of edge arguments infos is big enough to
 317    accommodate a structure for all edges and reallocates it if not.  */
 318
 319 static inline void
 320 ipa_check_create_edge_args (void)
 321 {
 322   if (!ipa_edge_args_vector)
 323     ipa_edge_args_vector = VEC_alloc (ipa_edge_args_t, gc,
 324                                       cgraph_edge_max_uid);
 325
 326   if (VEC_length (ipa_edge_args_t, ipa_edge_args_vector)
 327       <=  (unsigned) cgraph_edge_max_uid)
 328     VEC_safe_grow_cleared (ipa_edge_args_t, gc, ipa_edge_args_vector,
 329                            cgraph_edge_max_uid + 1);
 330 }
 331
 332 /* Returns true if the array of edge infos is large enough to accommodate an
 333    info for EDGE.  The main purpose of this function is that debug dumping
 334    function can check info availability without causing reallocations.  */
 335
 336 static inline bool
 337 ipa_edge_args_info_available_for_edge_p (struct cgraph_edge *edge)
 338 {
 339   return ((unsigned) edge->uid < VEC_length (ipa_edge_args_t,
 340                                              ipa_edge_args_vector));
 341 }
 342
 343 /* Function formal parameters related computations.  */
 344 void ipa_initialize_node_params (struct cgraph_node *node);
 345 bool ipa_propagate_indirect_call_infos (struct cgraph_edge *cs,
 346                                         VEC (cgraph_edge_p, heap) **new_edges);
 347
 348 /* Indirect edge and binfo processing.  */
 349 tree ipa_get_indirect_edge_target (struct cgraph_edge *ie,
 350                                    VEC (tree, heap) *known_csts,
 351                                    VEC (tree, heap) *known_binfs);
 352 struct cgraph_edge *ipa_make_edge_direct_to_target (struct cgraph_edge *, tree);
 353
 354 /* Functions related to both.  */
 355 void ipa_analyze_node (struct cgraph_node *);
 356
 357 /* Debugging interface.  */
 358 void ipa_print_node_params (FILE *, struct cgraph_node *node);
 359 void ipa_print_all_params (FILE *);
 360 void ipa_print_node_jump_functions (FILE *f, struct cgraph_node *node);
 361 void ipa_print_all_jump_functions (FILE * f);
 362 void ipcp_verify_propagated_values (void);
 363
 364 extern alloc_pool ipcp_values_pool;
 365 extern alloc_pool ipcp_sources_pool;
 366
 367 /* Structure to describe transformations of formal parameters and actual
 368    arguments.  Each instance describes one new parameter and they are meant to
 369    be stored in a vector.  Additionally, most users will probably want to store
 370    adjustments about parameters that are being removed altogether so that SSA
 371    names belonging to them can be replaced by SSA names of an artificial
 372    variable.  */
 373 struct ipa_parm_adjustment
 374 {
 375   /* The original PARM_DECL itself, helpful for processing of the body of the
 376      function itself.  Intended for traversing function bodies.
 377      ipa_modify_formal_parameters, ipa_modify_call_arguments and
 378      ipa_combine_adjustments ignore this and use base_index.
 379      ipa_modify_formal_parameters actually sets this.  */
 380   tree base;
 381
 382   /* Type of the new parameter.  However, if by_ref is true, the real type will
 383      be a pointer to this type.  */
 384   tree type;
 385
 386   /* Alias refrerence type to be used in MEM_REFs when adjusting caller
 387      arguments.  */
 388   tree alias_ptr_type;
 389
 390   /* The new declaration when creating/replacing a parameter.  Created by
 391      ipa_modify_formal_parameters, useful for functions modifying the body
 392      accordingly. */
 393   tree reduction;
 394
 395   /* New declaration of a substitute variable that we may use to replace all
 396      non-default-def ssa names when a parm decl is going away.  */
 397   tree new_ssa_base;
 398
 399   /* If non-NULL and the original parameter is to be removed (copy_param below
 400      is NULL), this is going to be its nonlocalized vars value.  */
 401   tree nonlocal_value;
 402
 403   /* Offset into the original parameter (for the cases when the new parameter
 404      is a component of an original one).  */
 405   HOST_WIDE_INT offset;
 406
 407   /* Zero based index of the original parameter this one is based on.  (ATM
 408      there is no way to insert a new parameter out of the blue because there is
 409      no need but if it arises the code can be easily exteded to do so.)  */
 410   int base_index;
 411
 412   /* This new parameter is an unmodified parameter at index base_index. */
 413   unsigned copy_param : 1;
 414
 415   /* This adjustment describes a parameter that is about to be removed
 416      completely.  Most users will probably need to book keep those so that they
 417      don't leave behinfd any non default def ssa names belonging to them.  */
 418   unsigned remove_param : 1;
 419
 420   /* The parameter is to be passed by reference.  */
 421   unsigned by_ref : 1;
 422 };
 423
 424 typedef struct ipa_parm_adjustment ipa_parm_adjustment_t;
 425 DEF_VEC_O (ipa_parm_adjustment_t);
 426 DEF_VEC_ALLOC_O (ipa_parm_adjustment_t, heap);
 427
 428 typedef VEC (ipa_parm_adjustment_t, heap) *ipa_parm_adjustment_vec;
 429
 430 VEC(tree, heap) *ipa_get_vector_of_formal_parms (tree fndecl);
 431 void ipa_modify_formal_parameters (tree fndecl, ipa_parm_adjustment_vec,
 432                                    const char *);
 433 void ipa_modify_call_arguments (struct cgraph_edge *, gimple,
 434                                 ipa_parm_adjustment_vec);
 435 ipa_parm_adjustment_vec ipa_combine_adjustments (ipa_parm_adjustment_vec,
 436                                                  ipa_parm_adjustment_vec);
 437 void ipa_dump_param_adjustments (FILE *, ipa_parm_adjustment_vec, tree);
 438
 439 void ipa_prop_write_jump_functions (cgraph_node_set set);
 440 void ipa_prop_read_jump_functions (void);
 441 void ipa_update_after_lto_read (void);
 442 int ipa_get_param_decl_index (struct ipa_node_params *, tree);
 443 tree ipa_value_from_jfunc (struct ipa_node_params *info,
 444                            struct ipa_jump_func *jfunc);
 445
 446
 447 /* From tree-sra.c:  */
 448 tree build_ref_for_offset (location_t, tree, HOST_WIDE_INT, tree,
 449                            gimple_stmt_iterator *, bool);
 450
 451 #endif /* IPA_PROP_H */