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.  */
  29
  30 /* A jump function for a callsite represents the values passed as actual
  31    arguments of the callsite. There are three main types of values :
  32    Formal - the caller's formal parameter is passed as an actual argument.
  33    Constant - a constant is passed as an actual argument.
  34    Unknown - neither of the above.
  35    Integer and real constants are represented as IPA_CONST and Fortran
  36    constants are represented as IPA_CONST_REF.  Finally, IPA_CONST_MEMBER_PTR
  37    stands for C++ member pointers constants.  */
  38 enum jump_func_type
  39 {
  40   IPA_UNKNOWN = 0,     /* newly allocated and zeroed jump functions default */
  41   IPA_CONST,
  42   IPA_CONST_REF,
  43   IPA_CONST_MEMBER_PTR,
  44   IPA_PASS_THROUGH
  45 };
  46
  47 /* All formal parameters in the program have a lattice associated with it
  48    computed by the interprocedural stage of IPCP.
  49    There are three main values of the lattice:
  50    IPA_TOP - unknown,
  51    IPA_BOTTOM - non constant,
  52    IPA_CONST_VALUE - simple scalar constant,
  53    Cval of formal f will have a constant value if all callsites to this
  54    function have the same constant value passed to f.
  55    Integer and real constants are represented as IPA_CONST and Fortran
  56    constants are represented as IPA_CONST_REF.  */
  57 enum ipa_lattice_type
  58 {
  59   IPA_BOTTOM,
  60   IPA_CONST_VALUE,
  61   IPA_CONST_VALUE_REF,
  62   IPA_TOP
  63 };
  64
  65 /* Structure holding a C++ member pointer constant.  Holds a pointer to the
  66    method and delta offset.  */
  67 struct ipa_member_ptr_cst
  68 {
  69   tree pfn;
  70   tree delta;
  71 };
  72
  73 /* Represents a value of a jump function.  formal_id is used only in jump
  74    function context and represents pass-through parameter (the formal parameter
  75    of the caller is passed as argument).  constant represents the actual
  76    constant in constant jump functions and member_cst holds constant c++ member
  77    functions.  */
  78 union jump_func_value
  79 {
  80   unsigned int formal_id;
  81   tree constant;
  82   struct ipa_member_ptr_cst member_cst;
  83 };
  84
  85 /* A jump function for a callsite represents the values passed as actual
  86    arguments of the callsite. See enum jump_func_type for the various
  87    types of jump functions supported.  */
  88 struct ipa_jump_func
  89 {
  90   enum jump_func_type type;
  91   union jump_func_value value;
  92 };
  93
  94 /* All formal parameters in the program have a cval computed by
  95    the interprocedural stage of IPCP. See enum ipa_lattice_type for
  96    the various types of lattices supported */
  97 struct ipcp_lattice
  98 {
  99   enum ipa_lattice_type type;
 100   tree constant;
 101 };
 102
 103 /* Represent which DECL tree (or reference to such tree)
 104    will be replaced by another tree while versioning.  */
 105 struct ipa_replace_map
 106 {
 107   /* The tree that will be replaced.  */
 108   tree old_tree;
 109   /* The new (replacing) tree.  */
 110   tree new_tree;
 111   /* True when a substitution should be done, false otherwise.  */
 112   bool replace_p;
 113   /* True when we replace a reference to old_tree.  */
 114   bool ref_p;
 115 };
 116
 117 /* ipa_param_flags contains various flags that describe how the associated
 118    parameter is treated within a function. */
 119 struct ipa_param_flags
 120 {
 121   /* Whether the value parameter has been modified within the function.  */
 122   unsigned modified : 1;
 123   /* Whether the parameter has been used as a call destination. */
 124   unsigned called : 1;
 125 };
 126
 127 /* Each instance of the following  structure describes a statement that calls a
 128    function parameter.  Those referring  to statements within the same function
 129    are linked in a list.  */
 130 struct ipa_param_call_note
 131 {
 132   /* Linked list's next */
 133   struct ipa_param_call_note *next;
 134   /* Statement that contains the call to the parameter above.  */
 135   gimple stmt;
 136   /* Index of the parameter that is called.  */
 137   unsigned int formal_id;
 138   /* Expected number of executions: calculated in profile.c.  */
 139   gcov_type count;
 140   /* Expected frequency of executions within the function. see cgraph_edge in
 141      cgraph.h for more on this. */
 142   int frequency;
 143   /* Depth of loop nest, 1 means no loop nest.  */
 144   int loop_nest;
 145   /* Set when we have already found the target to be a compile time constant
 146      and turned this into an edge or when the note was found unusable for some
 147      reason.  */
 148   bool processed;
 149 };
 150
 151 /* ipa_node_params stores information related to formal parameters of functions
 152    and some other information for interprocedural passes that operate on
 153    parameters (such as ipa-cp).  */
 154 struct ipa_node_params
 155 {
 156   /* Number of formal parameters of this function.  When set to 0,
 157      this function's parameters would not be analyzed by the different
 158      stages of IPA CP.  */
 159   int param_count;
 160   /* Array of lattices.  */
 161   struct ipcp_lattice *ipcp_lattices;
 162   /* Mapping each parameter to its PARM_DECL tree.  */
 163   tree *param_decls;
 164   /* Various flags describing individual parameters.  */
 165   struct ipa_param_flags *param_flags;
 166   /* List of structures enumerating calls to a formal parameter.  */
 167   struct ipa_param_call_note *param_calls;
 168   /* Only for versioned nodes this field would not be NULL,
 169      it points to the node that IPA cp cloned from.  */
 170   struct cgraph_node *ipcp_orig_node;
 171   /* Meaningful only for original functions.  Expresses the
 172      ratio between the direct calls and sum of all invocations of
 173      this function (given by profiling info).  It is used to calculate
 174      the profiling information of the original function and the versioned
 175      one.  */
 176   gcov_type count_scale;
 177
 178   /* Whether this function is called with variable number of actual
 179      arguments.  */
 180   unsigned called_with_var_arguments : 1;
 181   /* Whether the modification analysis has already been performed. */
 182   unsigned modification_analysis_done : 1;
 183   /* Whether the param uses analysis has already been performed.  */
 184   unsigned uses_analysis_done : 1;
 185 };
 186
 187 /* ipa_node_params access functions.  Please use these to access fields that
 188    are or will be shared among various passes.  */
 189
 190 /* Set the number of formal parameters. */
 191 static inline void
 192 ipa_set_param_count (struct ipa_node_params *info, int count)
 193 {
 194   info->param_count = count;
 195 }
 196
 197 /* Return the number of formal parameters. */
 198 static inline int
 199 ipa_get_param_count (struct ipa_node_params *info)
 200 {
 201   return info->param_count;
 202 }
 203
 204 /* Returns the declaration of ith param of the corresponding node.  Note there
 205    is no setter function as this array is built just once using
 206    ipa_create_param_decls_array. */
 207 static inline tree
 208 ipa_get_ith_param (struct ipa_node_params *info, int i)
 209 {
 210   return info->param_decls[i];
 211 }
 212
 213 /* Returns the modification flag corresponding to the ith parameter.  Note
 214    there is no setter method as the goal is to set all flags when building the
 215    array in ipa_detect_param_modifications.  */
 216 static inline bool
 217 ipa_is_ith_param_modified (struct ipa_node_params *info, int i)
 218 {
 219   return info->param_flags[i].modified;
 220 }
 221
 222 /* Returns the called flag corresponding o the ith paramterer.  Note there is
 223    no setter method as the goal is to set all flags when building the array in
 224    ipa_detect_called_params.  */
 225 static inline bool
 226 ipa_is_ith_param_called (struct ipa_node_params *info, int i)
 227 {
 228   return info->param_flags[i].called;
 229 }
 230
 231 /* Flag this node as having callers with variable number of arguments.  */
 232 static inline void
 233 ipa_set_called_with_variable_arg (struct ipa_node_params *info)
 234 {
 235   info->called_with_var_arguments = 1;
 236 }
 237
 238 /* Have we detected this node was called with variable number of arguments? */
 239 static inline bool
 240 ipa_is_called_with_var_arguments (struct ipa_node_params *info)
 241 {
 242   return info->called_with_var_arguments;
 243 }
 244
 245
 246
 247 /* ipa_edge_args stores information related to a callsite and particularly
 248    its arguments. It is pointed to by a field in the
 249    callsite's corresponding cgraph_edge.  */
 250 struct ipa_edge_args
 251 {
 252   /* Number of actual arguments in this callsite.  When set to 0,
 253      this callsite's parameters would not be analyzed by the different
 254      stages of IPA CP.  */
 255   int argument_count;
 256   /* Array of the callsite's jump function of each parameter.  */
 257   struct ipa_jump_func *jump_functions;
 258 };
 259
 260 /* ipa_edge_args access functions.  Please use these to access fields that
 261    are or will be shared among various passes.  */
 262
 263 /* Set the number of actual arguments. */
 264 static inline void
 265 ipa_set_cs_argument_count (struct ipa_edge_args *args, int count)
 266 {
 267   args->argument_count = count;
 268 }
 269
 270 /* Return the number of actual arguments. */
 271 static inline int
 272 ipa_get_cs_argument_count (struct ipa_edge_args *args)
 273 {
 274   return args->argument_count;
 275 }
 276
 277 /* Returns a pointer to the jump function for the ith argument.  Please note
 278    there is no setter function as jump functions are all set up in
 279    ipa_compute_jump_functions. */
 280 static inline struct ipa_jump_func *
 281 ipa_get_ith_jump_func (struct ipa_edge_args *args, int i)
 282 {
 283   return &args->jump_functions[i];
 284 }
 285
 286 /* Vectors need to have typedefs of structures.  */
 287 typedef struct ipa_node_params ipa_node_params_t;
 288 typedef struct ipa_edge_args ipa_edge_args_t;
 289
 290 /* Types of vectors hodling the infos.  */
 291 DEF_VEC_O (ipa_node_params_t);
 292 DEF_VEC_ALLOC_O (ipa_node_params_t, heap);
 293 DEF_VEC_O (ipa_edge_args_t);
 294 DEF_VEC_ALLOC_O (ipa_edge_args_t, heap);
 295
 296 /* Vector where the parameter infos are actually stored. */
 297 extern VEC (ipa_node_params_t, heap) *ipa_node_params_vector;
 298 /* Vector where the parameter infos are actually stored. */
 299 extern VEC (ipa_edge_args_t, heap) *ipa_edge_args_vector;
 300
 301 /* Return the associated parameter/argument info corresponding to the given
 302    node/edge.  */
 303 #define IPA_NODE_REF(NODE) (VEC_index (ipa_node_params_t, \
 304                                        ipa_node_params_vector, (NODE)->uid))
 305 #define IPA_EDGE_REF(EDGE) (VEC_index (ipa_edge_args_t, \
 306                                        ipa_edge_args_vector, (EDGE)->uid))
 307 /* This macro checks validity of index returned by
 308    ipa_get_param_decl_index function.  */
 309 #define IS_VALID_JUMP_FUNC_INDEX(I) ((I) != -1)
 310
 311 /* Creating and freeing ipa_node_params and ipa_edge_args.  */
 312 void ipa_create_all_node_params (void);
 313 void ipa_create_all_edge_args (void);
 314 void ipa_free_edge_args_substructures (struct ipa_edge_args *);
 315 void ipa_free_node_params_substructures (struct ipa_node_params *);
 316 void ipa_free_all_node_params (void);
 317 void ipa_free_all_edge_args (void);
 318 void free_all_ipa_structures_after_ipa_cp (void);
 319 void free_all_ipa_structures_after_iinln (void);
 320 void ipa_register_cgraph_hooks (void);
 321
 322 /* This function ensures the array of node param infos is big enough to
 323    accomdate a structure for all nodes and realloacates it if not.  */
 324 static inline void
 325 ipa_check_create_node_params (void)
 326 {
 327   if (!ipa_node_params_vector)
 328     ipa_node_params_vector = VEC_alloc (ipa_node_params_t, heap,
 329                                         cgraph_max_uid);
 330
 331   if (VEC_length (ipa_node_params_t, ipa_node_params_vector)
 332       <= (unsigned) cgraph_max_uid)
 333     VEC_safe_grow_cleared (ipa_node_params_t, heap,
 334                            ipa_node_params_vector, cgraph_max_uid + 1);
 335 }
 336
 337 /* This function ensures the array of adge arguments infos is big enough to
 338    accomdate a structure for all edges and realloacates it if not.  */
 339 static inline void
 340 ipa_check_create_edge_args (void)
 341 {
 342   if (!ipa_edge_args_vector)
 343     ipa_edge_args_vector = VEC_alloc (ipa_edge_args_t, heap,
 344                                       cgraph_edge_max_uid);
 345
 346   if (VEC_length (ipa_edge_args_t, ipa_edge_args_vector)
 347       <=  (unsigned) cgraph_edge_max_uid)
 348     VEC_safe_grow_cleared (ipa_edge_args_t, heap, ipa_edge_args_vector,
 349                            cgraph_edge_max_uid + 1);
 350 }
 351
 352 /* Returns true if the array of edge infos is large enough to accomodate an
 353    info for EDGE.  The main purpose of this function is that debug dumping
 354    function can check info availability without causing reallocations.  */
 355 static inline bool
 356 ipa_edge_args_info_available_for_edge_p (struct cgraph_edge *edge)
 357 {
 358   return ((unsigned) edge->uid < VEC_length (ipa_edge_args_t,
 359                                              ipa_edge_args_vector));
 360 }
 361
 362 /* A function list element.  It is used to create a temporary worklist used in
 363    the propagation stage of IPCP. (can be used for more IPA optimizations)  */
 364 struct ipa_func_list
 365 {
 366   struct cgraph_node *node;
 367   struct ipa_func_list *next;
 368 };
 369
 370 /* ipa_func_list interface.  */
 371 struct ipa_func_list *ipa_init_func_list (void);
 372 void ipa_push_func_to_list (struct ipa_func_list **, struct cgraph_node *);
 373 struct cgraph_node *ipa_pop_func_from_list (struct ipa_func_list **);
 374
 375 /* Callsite related calculations.  */
 376 void ipa_compute_jump_functions (struct cgraph_edge *);
 377 void ipa_count_arguments (struct cgraph_edge *);
 378
 379 /* Function parameters related computations.  */
 380 void ipa_count_formal_params (struct cgraph_node *);
 381 void ipa_create_param_decls_array (struct cgraph_node *);
 382 void ipa_detect_param_modifications (struct cgraph_node *);
 383 void ipa_analyze_params_uses (struct cgraph_node *);
 384 void ipa_propagate_indirect_call_infos (struct cgraph_edge *cs,
 385                                         VEC (cgraph_edge_p, heap) *new_edges);
 386
 387 /* Debugging interface.  */
 388 void ipa_print_all_tree_maps (FILE *);
 389 void ipa_print_node_param_flags (FILE * f, struct cgraph_node *node);
 390 void ipa_print_all_param_flags (FILE *);
 391 void ipa_print_node_jump_functions (FILE *f, struct cgraph_node *node);
 392 void ipa_print_all_jump_functions (FILE * f);
 393
 394 #endif /* IPA_PROP_H */