gcc/langhooks.h

   1 /* The lang_hooks data structure.
   2    Copyright (C) 2001-2016 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
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 3, or (at your option)
   9 any later version.
  10
  11 GCC is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU General Public License 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 GCC_LANG_HOOKS_H
  21 #define GCC_LANG_HOOKS_H
  22
  23 /* FIXME: This file should be #include-d after tree.h (for enum tree_code).  */
  24
  25 struct diagnostic_info;
  26
  27 struct gimplify_omp_ctx;
  28
  29 struct array_descr_info;
  30
  31 /* A print hook for print_tree ().  */
  32 typedef void (*lang_print_tree_hook) (FILE *, tree, int indent);
  33
  34 enum classify_record
  35   { RECORD_IS_STRUCT, RECORD_IS_CLASS, RECORD_IS_INTERFACE };
  36
  37 class substring_loc;
  38
  39 /* The following hooks are documented in langhooks.c.  Must not be
  40    NULL.  */
  41
  42 struct lang_hooks_for_tree_inlining
  43 {
  44   bool (*var_mod_type_p) (tree, tree);
  45 };
  46
  47 /* The following hooks are used by tree-dump.c.  */
  48
  49 struct lang_hooks_for_tree_dump
  50 {
  51   /* Dump language-specific parts of tree nodes.  Returns nonzero if it
  52      does not want the usual dumping of the second argument.  */
  53   bool (*dump_tree) (void *, tree);
  54
  55   /* Determine type qualifiers in a language-specific way.  */
  56   int (*type_quals) (const_tree);
  57 };
  58
  59 /* Hooks related to types.  */
  60
  61 struct lang_hooks_for_types
  62 {
  63   /* Return a new type (with the indicated CODE), doing whatever
  64      language-specific processing is required.  */
  65   tree (*make_type) (enum tree_code);
  66
  67   /* Return what kind of RECORD_TYPE this is, mainly for purposes of
  68      debug information.  If not defined, record types are assumed to
  69      be structures.  */
  70   enum classify_record (*classify_record) (tree);
  71
  72   /* Given MODE and UNSIGNEDP, return a suitable type-tree with that
  73      mode.  */
  74   tree (*type_for_mode) (machine_mode, int);
  75
  76   /* Given PRECISION and UNSIGNEDP, return a suitable type-tree for an
  77      integer type with at least that precision.  */
  78   tree (*type_for_size) (unsigned, int);
  79
  80   /* True if the type is an instantiation of a generic type,
  81      e.g. C++ template implicit specializations.  */
  82   bool (*generic_p) (const_tree);
  83
  84   /* Returns the TREE_VEC of elements of a given generic argument pack.  */
  85   tree (*get_argument_pack_elems) (const_tree);
  86
  87   /* Given a type, apply default promotions to unnamed function
  88      arguments and return the new type.  Return the same type if no
  89      change.  Required by any language that supports variadic
  90      arguments.  The default hook dies.  */
  91   tree (*type_promotes_to) (tree);
  92
  93   /* Register TYPE as a builtin type with the indicated NAME.  The
  94      TYPE is placed in the outermost lexical scope.  The semantics
  95      should be analogous to:
  96
  97        typedef TYPE NAME;
  98
  99      in C.  The default hook ignores the declaration.  */
 100   void (*register_builtin_type) (tree, const char *);
 101
 102   /* This routine is called in tree.c to print an error message for
 103      invalid use of an incomplete type.  VALUE is the expression that
 104      was used (or 0 if that isn't known) and TYPE is the type that was
 105      invalid.  LOC is the location of the use.  */
 106   void (*incomplete_type_error) (location_t loc, const_tree value,
 107                                  const_tree type);
 108
 109   /* Called from assign_temp to return the maximum size, if there is one,
 110      for a type.  */
 111   tree (*max_size) (const_tree);
 112
 113   /* Register language specific type size variables as potentially OpenMP
 114      firstprivate variables.  */
 115   void (*omp_firstprivatize_type_sizes) (struct gimplify_omp_ctx *, tree);
 116
 117   /* Return true if TYPE is a mappable type.  */
 118   bool (*omp_mappable_type) (tree type);
 119
 120   /* Return TRUE if TYPE1 and TYPE2 are identical for type hashing purposes.
 121      Called only after doing all language independent checks.
 122      At present, this function is only called when both TYPE1 and TYPE2 are
 123      FUNCTION_TYPE or METHOD_TYPE.  */
 124   bool (*type_hash_eq) (const_tree, const_tree);
 125
 126   /* Return TRUE if TYPE uses a hidden descriptor and fills in information
 127      for the debugger about the array bounds, strides, etc.  */
 128   bool (*get_array_descr_info) (const_tree, struct array_descr_info *);
 129
 130   /* Fill in information for the debugger about the bounds of TYPE.  */
 131   void (*get_subrange_bounds) (const_tree, tree *, tree *);
 132
 133   /* Called on INTEGER_TYPEs.  Return NULL_TREE for non-biased types.  For
 134      biased types, return as an INTEGER_CST node the value that is represented
 135      by a physical zero.  */
 136   tree (*get_type_bias) (const_tree);
 137
 138   /* A type descriptive of TYPE's complex layout generated to help the
 139      debugger to decode variable-length or self-referential constructs.
 140      This is only used for the AT_GNAT_descriptive_type DWARF attribute.  */
 141   tree (*descriptive_type) (const_tree);
 142
 143   /* If we requested a pointer to a vector, build up the pointers that
 144      we stripped off while looking for the inner type.  Similarly for
 145      return values from functions.  The argument TYPE is the top of the
 146      chain, and BOTTOM is the new type which we will point to.  */
 147   tree (*reconstruct_complex_type) (tree, tree);
 148
 149   /* Returns the tree that represents the underlying data type used to
 150      implement the enumeration.  The default implementation will just use
 151      type_for_size.  Used in dwarf2out.c to add a DW_AT_type base type
 152      reference to a DW_TAG_enumeration.  */
 153   tree (*enum_underlying_base_type) (const_tree);
 154
 155   /* Return a type to use in the debug info instead of TYPE, or NULL_TREE to
 156      keep TYPE.  This is useful to keep a single "source type" when the
 157      middle-end uses specialized types, for instance constrained discriminated
 158      types in Ada.  */
 159   tree (*get_debug_type) (const_tree);
 160
 161   /* Return TRUE if TYPE implements a fixed point type and fills in information
 162      for the debugger about scale factor, etc.  */
 163   bool (*get_fixed_point_type_info) (const_tree,
 164                                      struct fixed_point_type_info *);
 165
 166   /* Returns -1 if dwarf ATTR shouldn't be added for TYPE, or the attribute
 167      value otherwise.  */
 168   int (*type_dwarf_attribute) (const_tree, int);
 169 };
 170
 171 /* Language hooks related to decls and the symbol table.  */
 172
 173 struct lang_hooks_for_decls
 174 {
 175   /* Return true if we are in the global binding level.  This hook is really
 176      needed only if the language supports variable-sized types at the global
 177      level, i.e. declared outside subprograms.  */
 178   bool (*global_bindings_p) (void);
 179
 180   /* Function to add a decl to the current scope level.  Takes one
 181      argument, a decl to add.  Returns that decl, or, if the same
 182      symbol is already declared, may return a different decl for that
 183      name.  */
 184   tree (*pushdecl) (tree);
 185
 186   /* Returns the chain of decls so far in the current scope level.  */
 187   tree (*getdecls) (void);
 188
 189   /* Returns -1 if dwarf ATTR shouldn't be added for DECL, or the attribute
 190      value otherwise.  */
 191   int (*decl_dwarf_attribute) (const_tree, int);
 192
 193   /* Returns True if the parameter is a generic parameter decl
 194      of a generic type, e.g a template template parameter for the C++ FE.  */
 195   bool (*generic_generic_parameter_decl_p) (const_tree);
 196
 197   /* Determine if a function parameter got expanded from a
 198      function parameter pack.  */
 199   bool (*function_parm_expanded_from_pack_p) (tree, tree);
 200
 201   /* Returns the generic declaration of a generic function instantiations.  */
 202   tree (*get_generic_function_decl) (const_tree);
 203
 204   /* Returns true when we should warn for an unused global DECL.
 205      We will already have checked that it has static binding.  */
 206   bool (*warn_unused_global) (const_tree);
 207
 208   /* Perform any post compilation-proper parser cleanups and
 209      processing.  This is currently only needed for the C++ parser,
 210      which hopefully can be cleaned up so this hook is no longer
 211      necessary.  */
 212   void (*post_compilation_parsing_cleanups) (void);
 213
 214   /* True if this decl may be called via a sibcall.  */
 215   bool (*ok_for_sibcall) (const_tree);
 216
 217   /* True if OpenMP should privatize what this DECL points to rather
 218      than the DECL itself.  */
 219   bool (*omp_privatize_by_reference) (const_tree);
 220
 221   /* Return sharing kind if OpenMP sharing attribute of DECL is
 222      predetermined, OMP_CLAUSE_DEFAULT_UNSPECIFIED otherwise.  */
 223   enum omp_clause_default_kind (*omp_predetermined_sharing) (tree);
 224
 225   /* Return decl that should be reported for DEFAULT(NONE) failure
 226      diagnostics.  Usually the DECL passed in.  */
 227   tree (*omp_report_decl) (tree);
 228
 229   /* Return true if DECL's DECL_VALUE_EXPR (if any) should be
 230      disregarded in OpenMP construct, because it is going to be
 231      remapped during OpenMP lowering.  SHARED is true if DECL
 232      is going to be shared, false if it is going to be privatized.  */
 233   bool (*omp_disregard_value_expr) (tree, bool);
 234
 235   /* Return true if DECL that is shared iff SHARED is true should
 236      be put into OMP_CLAUSE_PRIVATE_DEBUG.  */
 237   bool (*omp_private_debug_clause) (tree, bool);
 238
 239   /* Return true if DECL in private clause needs
 240      OMP_CLAUSE_PRIVATE_OUTER_REF on the private clause.  */
 241   bool (*omp_private_outer_ref) (tree);
 242
 243   /* Build and return code for a default constructor for DECL in
 244      response to CLAUSE.  OUTER is corresponding outer region's
 245      variable if needed.  Return NULL if nothing to be done.  */
 246   tree (*omp_clause_default_ctor) (tree clause, tree decl, tree outer);
 247
 248   /* Build and return code for a copy constructor from SRC to DST.  */
 249   tree (*omp_clause_copy_ctor) (tree clause, tree dst, tree src);
 250
 251   /* Similarly, except use an assignment operator instead.  */
 252   tree (*omp_clause_assign_op) (tree clause, tree dst, tree src);
 253
 254   /* Build and return code for a constructor of DST that sets it to
 255      SRC + ADD.  */
 256   tree (*omp_clause_linear_ctor) (tree clause, tree dst, tree src, tree add);
 257
 258   /* Build and return code destructing DECL.  Return NULL if nothing
 259      to be done.  */
 260   tree (*omp_clause_dtor) (tree clause, tree decl);
 261
 262   /* Do language specific checking on an implicitly determined clause.  */
 263   void (*omp_finish_clause) (tree clause, gimple_seq *pre_p);
 264
 265   /* Return true if DECL is a scalar variable (for the purpose of
 266      implicit firstprivatization).  */
 267   bool (*omp_scalar_p) (tree decl);
 268 };
 269
 270 /* Language hooks related to LTO serialization.  */
 271
 272 struct lang_hooks_for_lto
 273 {
 274   /* Begin a new LTO section named NAME.  */
 275   void (*begin_section) (const char *name);
 276
 277   /* Write DATA of length LEN to the currently open LTO section.  BLOCK is a
 278      pointer to the dynamically allocated memory containing DATA.  The
 279      append_data function is responsible for freeing it when it is no longer
 280      needed.  */
 281   void (*append_data) (const void *data, size_t len, void *block);
 282
 283   /* End the previously begun LTO section.  */
 284   void (*end_section) (void);
 285 };
 286
 287 /* Language-specific hooks.  See langhooks-def.h for defaults.  */
 288
 289 struct lang_hooks
 290 {
 291   /* String identifying the front end and optionally language standard
 292      version, e.g. "GNU C++98" or "GNU Java".  */
 293   const char *name;
 294
 295   /* sizeof (struct lang_identifier), so make_node () creates
 296      identifier nodes long enough for the language-specific slots.  */
 297   size_t identifier_size;
 298
 299   /* Remove any parts of the tree that are used only by the FE. */
 300   void (*free_lang_data) (tree);
 301
 302   /* Determines the size of any language-specific tcc_constant or
 303      tcc_exceptional nodes.  Since it is called from make_node, the
 304      only information available is the tree code.  Expected to die
 305      on unrecognized codes.  */
 306   size_t (*tree_size) (enum tree_code);
 307
 308   /* Return the language mask used for converting argv into a sequence
 309      of options.  */
 310   unsigned int (*option_lang_mask) (void);
 311
 312   /* Initialize variables in an options structure.  */
 313   void (*init_options_struct) (struct gcc_options *opts);
 314
 315   /* After the initialize_diagnostics hook is called, do any simple
 316      initialization needed before any calls to handle_option, other
 317      than that done by the init_options_struct hook.  */
 318   void (*init_options) (unsigned int decoded_options_count,
 319                         struct cl_decoded_option *decoded_options);
 320
 321   /* Callback used to perform language-specific initialization for the
 322      global diagnostic context structure.  */
 323   void (*initialize_diagnostics) (diagnostic_context *);
 324
 325   /* Return true if a warning should be given about option OPTION,
 326      which is for the wrong language, false if it should be quietly
 327      ignored.  */
 328   bool (*complain_wrong_lang_p) (const struct cl_option *option);
 329
 330   /* Handle the switch CODE, which has real type enum opt_code from
 331      options.h.  If the switch takes an argument, it is passed in ARG
 332      which points to permanent storage.  The handler is responsible for
 333      checking whether ARG is NULL, which indicates that no argument
 334      was in fact supplied.  For -f and -W switches, VALUE is 1 or 0
 335      for the positive and negative forms respectively.  HANDLERS should
 336      be passed to any recursive handle_option calls.  LOC is the
 337      location of the option.
 338
 339      Return true if the switch is valid, false if invalid.  */
 340   bool (*handle_option) (size_t code, const char *arg, int value, int kind,
 341                          location_t loc,
 342                          const struct cl_option_handlers *handlers);
 343
 344   /* Called when all command line options have been parsed to allow
 345      further processing and initialization
 346
 347      Should return true to indicate that a compiler back-end is
 348      not required, such as with the -E option.
 349
 350      If errorcount is nonzero after this call the compiler exits
 351      immediately and the finish hook is not called.  */
 352   bool (*post_options) (const char **);
 353
 354   /* Called after post_options to initialize the front end.  Return
 355      false to indicate that no further compilation be performed, in
 356      which case the finish hook is called immediately.  */
 357   bool (*init) (void);
 358
 359   /* Called at the end of compilation, as a finalizer.  */
 360   void (*finish) (void);
 361
 362   /* Parses the entire file.  */
 363   void (*parse_file) (void);
 364
 365   /* Determines if it's ok for a function to have no noreturn attribute.  */
 366   bool (*missing_noreturn_ok_p) (tree);
 367
 368   /* Called to obtain the alias set to be used for an expression or type.
 369      Returns -1 if the language does nothing special for it.  */
 370   alias_set_type (*get_alias_set) (tree);
 371
 372   /* Function to finish handling an incomplete decl at the end of
 373      compilation.  Default hook is does nothing.  */
 374   void (*finish_incomplete_decl) (tree);
 375
 376   /* Replace the DECL_LANG_SPECIFIC data, which may be NULL, of the
 377      DECL_NODE with a newly GC-allocated copy.  */
 378   void (*dup_lang_specific_decl) (tree);
 379
 380   /* Set the DECL_ASSEMBLER_NAME for a node.  If it is the sort of
 381      thing that the assembler should talk about, set
 382      DECL_ASSEMBLER_NAME to an appropriate IDENTIFIER_NODE.
 383      Otherwise, set it to the ERROR_MARK_NODE to ensure that the
 384      assembler does not talk about it.  */
 385   void (*set_decl_assembler_name) (tree);
 386
 387   /* The front end can add its own statistics to -fmem-report with
 388      this hook.  It should output to stderr.  */
 389   void (*print_statistics) (void);
 390
 391   /* Called by print_tree when there is a tree of class tcc_exceptional
 392      that it doesn't know how to display.  */
 393   lang_print_tree_hook print_xnode;
 394
 395   /* Called to print language-dependent parts of tcc_decl, tcc_type,
 396      and IDENTIFIER_NODE nodes.  */
 397   lang_print_tree_hook print_decl;
 398   lang_print_tree_hook print_type;
 399   lang_print_tree_hook print_identifier;
 400
 401   /* Computes the name to use to print a declaration.  DECL is the
 402      non-NULL declaration in question.  VERBOSITY determines what
 403      information will be printed: 0: DECL_NAME, demangled as
 404      necessary.  1: and scope information.  2: and any other
 405      information that might be interesting, such as function parameter
 406      types in C++.  The name is in the internal character set and
 407      needs to be converted to the locale character set of diagnostics,
 408      or to the execution character set for strings such as
 409      __PRETTY_FUNCTION__.  */
 410   const char *(*decl_printable_name) (tree decl, int verbosity);
 411
 412   /* Computes the dwarf-2/3 name for a tree.  VERBOSITY determines what
 413      information will be printed: 0: DECL_NAME, demangled as
 414      necessary.  1: and scope information.  */
 415   const char *(*dwarf_name) (tree, int verbosity);
 416
 417   /* This compares two types for equivalence ("compatible" in C-based languages).
 418      This routine should only return 1 if it is sure.  It should not be used
 419      in contexts where erroneously returning 0 causes problems.  */
 420   int (*types_compatible_p) (tree x, tree y);
 421
 422   /* Called by report_error_function to print out function name.  */
 423   void (*print_error_function) (diagnostic_context *, const char *,
 424                                 struct diagnostic_info *);
 425
 426   /* Convert a character from the host's to the target's character
 427      set.  The character should be in what C calls the "basic source
 428      character set" (roughly, the set of characters defined by plain
 429      old ASCII).  The default is to return the character unchanged,
 430      which is correct in most circumstances.  Note that both argument
 431      and result should be sign-extended under -fsigned-char,
 432      zero-extended under -fno-signed-char.  */
 433   HOST_WIDE_INT (*to_target_charset) (HOST_WIDE_INT);
 434
 435   /* Pointers to machine-independent attribute tables, for front ends
 436      using attribs.c.  If one is NULL, it is ignored.  Respectively, a
 437      table of attributes specific to the language, a table of
 438      attributes common to two or more languages (to allow easy
 439      sharing), and a table of attributes for checking formats.  */
 440   const struct attribute_spec *attribute_table;
 441   const struct attribute_spec *common_attribute_table;
 442   const struct attribute_spec *format_attribute_table;
 443
 444   struct lang_hooks_for_tree_inlining tree_inlining;
 445
 446   struct lang_hooks_for_tree_dump tree_dump;
 447
 448   struct lang_hooks_for_decls decls;
 449
 450   struct lang_hooks_for_types types;
 451
 452   struct lang_hooks_for_lto lto;
 453
 454   /* Returns a TREE_VEC of the generic parameters of an instantiation of
 455      a generic type or decl, e.g. C++ template instantiation.  If
 456      TREE_CHAIN of the return value is set, it is an INTEGER_CST
 457      indicating how many of the elements are non-default.  */
 458   tree (*get_innermost_generic_parms) (const_tree);
 459
 460   /* Returns the TREE_VEC of arguments of an instantiation
 461      of a generic type of decl, e.g. C++ template instantiation.  */
 462   tree (*get_innermost_generic_args) (const_tree);
 463
 464   /* Determine if a tree is a function parameter pack.  */
 465   bool (*function_parameter_pack_p) (const_tree);
 466
 467   /* Perform language-specific gimplification on the argument.  Returns an
 468      enum gimplify_status, though we can't see that type here.  */
 469   int (*gimplify_expr) (tree *, gimple_seq *, gimple_seq *);
 470
 471   /* Do language specific processing in the builtin function DECL  */
 472   tree (*builtin_function) (tree decl);
 473
 474   /* Like builtin_function, but make sure the scope is the external scope.
 475      This is used to delay putting in back end builtin functions until the ISA
 476      that defines the builtin is declared via function specific target options,
 477      which can save memory for machines like the x86_64 that have multiple
 478      ISAs.  If this points to the same function as builtin_function, the
 479      backend must add all of the builtins at program initialization time.  */
 480   tree (*builtin_function_ext_scope) (tree decl);
 481
 482   /* Used to set up the tree_contains_structure array for a frontend. */
 483   void (*init_ts) (void);
 484
 485   /* Called by recompute_tree_invariant_for_addr_expr to go from EXPR
 486      to a contained expression or DECL, possibly updating *TC or *SE
 487      if in the process TREE_CONSTANT or TREE_SIDE_EFFECTS need updating.  */
 488   tree (*expr_to_decl) (tree expr, bool *tc, bool *se);
 489
 490   /* The EH personality function decl.  */
 491   tree (*eh_personality) (void);
 492
 493   /* Map a type to a runtime object to match type.  */
 494   tree (*eh_runtime_type) (tree);
 495
 496   /* If non-NULL, this is a function that returns a function decl to be
 497      executed if an unhandled exception is propagated out of a cleanup
 498      region.  For example, in C++, an exception thrown by a destructor
 499      during stack unwinding is required to result in a call to
 500      `std::terminate', so the C++ version of this function returns a
 501      FUNCTION_DECL for `std::terminate'.  */
 502   tree (*eh_protect_cleanup_actions) (void);
 503
 504   /* Return true if a stmt can fallthru.  Used by block_may_fallthru
 505      to possibly handle language trees.  */
 506   bool (*block_may_fallthru) (const_tree);
 507
 508   /* True if this language uses __cxa_end_cleanup when the ARM EABI
 509      is enabled.  */
 510   bool eh_use_cxa_end_cleanup;
 511
 512   /* True if this language requires deep unsharing of tree nodes prior to
 513      gimplification.  */
 514   bool deep_unsharing;
 515
 516   /* True if this language may use custom descriptors for nested functions
 517      instead of trampolines.  */
 518   bool custom_function_descriptors;
 519
 520   /* Run all lang-specific selftests.  */
 521   void (*run_lang_selftests) (void);
 522
 523   /* Attempt to determine the source location of the substring.
 524      If successful, return NULL and write the source location to *OUT_LOC.
 525      Otherwise return an error message.  Error messages are intended
 526      for GCC developers (to help debugging) rather than for end-users.  */
 527   const char *(*get_substring_location) (const substring_loc &,
 528                                          location_t *out_loc);
 529
 530   /* Whenever you add entries here, make sure you adjust langhooks-def.h
 531      and langhooks.c accordingly.  */
 532 };
 533
 534 /* Each front end provides its own.  */
 535 extern struct lang_hooks lang_hooks;
 536
 537 extern tree add_builtin_function (const char *name, tree type,
 538                                   int function_code, enum built_in_class cl,
 539                                   const char *library_name,
 540                                   tree attrs);
 541
 542 extern tree add_builtin_function_ext_scope (const char *name, tree type,
 543                                             int function_code,
 544                                             enum built_in_class cl,
 545                                             const char *library_name,
 546                                             tree attrs);
 547 extern tree add_builtin_type (const char *name, tree type);
 548
 549 /* Language helper functions.  */
 550
 551 extern bool lang_GNU_C (void);
 552 extern bool lang_GNU_CXX (void);
 553 extern bool lang_GNU_Fortran (void);
 554 extern bool lang_GNU_OBJC (void);
 555
 556 #endif /* GCC_LANG_HOOKS_H */