gcc/langhooks.h

   1 /* The lang_hooks data structure.
   2    Copyright (C) 2001-2021 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   /* Make an enum type with the given name and values, associating
  68      them all with the given source location.  */
  69   tree (*simulate_enum_decl) (location_t, const char *, vec<string_int_pair>);
  70
  71   /* Return what kind of RECORD_TYPE this is, mainly for purposes of
  72      debug information.  If not defined, record types are assumed to
  73      be structures.  */
  74   enum classify_record (*classify_record) (tree);
  75
  76   /* Given MODE and UNSIGNEDP, return a suitable type-tree with that
  77      mode.  */
  78   tree (*type_for_mode) (machine_mode, int);
  79
  80   /* Given PRECISION and UNSIGNEDP, return a suitable type-tree for an
  81      integer type with at least that precision.  */
  82   tree (*type_for_size) (unsigned, int);
  83
  84   /* True if the type is an instantiation of a generic type,
  85      e.g. C++ template implicit specializations.  */
  86   bool (*generic_p) (const_tree);
  87
  88   /* Returns the TREE_VEC of elements of a given generic argument pack.  */
  89   tree (*get_argument_pack_elems) (const_tree);
  90
  91   /* Given a type, apply default promotions to unnamed function
  92      arguments and return the new type.  Return the same type if no
  93      change.  Required by any language that supports variadic
  94      arguments.  The default hook dies.  */
  95   tree (*type_promotes_to) (tree);
  96
  97   /* Register TYPE as a builtin type with the indicated NAME.  The
  98      TYPE is placed in the outermost lexical scope.  The semantics
  99      should be analogous to:
 100
 101        typedef TYPE NAME;
 102
 103      in C.  The default hook ignores the declaration.  */
 104   void (*register_builtin_type) (tree, const char *);
 105
 106   /* This routine is called in tree.c to print an error message for
 107      invalid use of an incomplete type.  VALUE is the expression that
 108      was used (or 0 if that isn't known) and TYPE is the type that was
 109      invalid.  LOC is the location of the use.  */
 110   void (*incomplete_type_error) (location_t loc, const_tree value,
 111                                  const_tree type);
 112
 113   /* Called from assign_temp to return the maximum size, if there is one,
 114      for a type.  */
 115   tree (*max_size) (const_tree);
 116
 117   /* Register language specific type size variables as potentially OpenMP
 118      firstprivate variables.  */
 119   void (*omp_firstprivatize_type_sizes) (struct gimplify_omp_ctx *, tree);
 120
 121   /* Return true if TYPE is a mappable type.  */
 122   bool (*omp_mappable_type) (tree type);
 123
 124   /* Return TRUE if TYPE1 and TYPE2 are identical for type hashing purposes.
 125      Called only after doing all language independent checks.
 126      At present, this function is only called when both TYPE1 and TYPE2 are
 127      FUNCTION_TYPE or METHOD_TYPE.  */
 128   bool (*type_hash_eq) (const_tree, const_tree);
 129
 130   /* If non-NULL, return TYPE1 with any language-specific modifiers copied from
 131      TYPE2.  */
 132   tree (*copy_lang_qualifiers) (const_tree, const_tree);
 133
 134   /* Return TRUE if TYPE uses a hidden descriptor and fills in information
 135      for the debugger about the array bounds, strides, etc.  */
 136   bool (*get_array_descr_info) (const_tree, struct array_descr_info *);
 137
 138   /* Fill in information for the debugger about the bounds of TYPE.  */
 139   void (*get_subrange_bounds) (const_tree, tree *, tree *);
 140
 141   /* Called on INTEGER_TYPEs.  Return NULL_TREE for non-biased types.  For
 142      biased types, return as an INTEGER_CST node the value that is represented
 143      by a physical zero.  */
 144   tree (*get_type_bias) (const_tree);
 145
 146   /* A type descriptive of TYPE's complex layout generated to help the
 147      debugger to decode variable-length or self-referential constructs.
 148      This is only used for the AT_GNAT_descriptive_type DWARF attribute.  */
 149   tree (*descriptive_type) (const_tree);
 150
 151   /* If we requested a pointer to a vector, build up the pointers that
 152      we stripped off while looking for the inner type.  Similarly for
 153      return values from functions.  The argument TYPE is the top of the
 154      chain, and BOTTOM is the new type which we will point to.  */
 155   tree (*reconstruct_complex_type) (tree, tree);
 156
 157   /* Returns the tree that represents the underlying data type used to
 158      implement the enumeration.  The default implementation will just use
 159      type_for_size.  Used in dwarf2out.c to add a DW_AT_type base type
 160      reference to a DW_TAG_enumeration.  */
 161   tree (*enum_underlying_base_type) (const_tree);
 162
 163   /* Return a type to use in the debug info instead of TYPE, or NULL_TREE to
 164      keep TYPE.  This is useful to keep a single "source type" when the
 165      middle-end uses specialized types, for instance constrained discriminated
 166      types in Ada.  */
 167   tree (*get_debug_type) (const_tree);
 168
 169   /* Return TRUE if TYPE implements a fixed point type and fills in information
 170      for the debugger about scale factor, etc.  */
 171   bool (*get_fixed_point_type_info) (const_tree,
 172                                      struct fixed_point_type_info *);
 173
 174   /* Returns -1 if dwarf ATTR shouldn't be added for TYPE, or the attribute
 175      value otherwise.  */
 176   int (*type_dwarf_attribute) (const_tree, int);
 177
 178   /* Returns a tree for the unit size of T excluding tail padding that
 179      might be used by objects inheriting from T.  */
 180   tree (*unit_size_without_reusable_padding) (tree);
 181 };
 182
 183 /* Language hooks related to decls and the symbol table.  */
 184
 185 struct lang_hooks_for_decls
 186 {
 187   /* Return true if we are in the global binding level.  This hook is really
 188      needed only if the language supports variable-sized types at the global
 189      level, i.e. declared outside subprograms.  */
 190   bool (*global_bindings_p) (void);
 191
 192   /* Function to add a decl to the current scope level.  Takes one
 193      argument, a decl to add.  Returns that decl, or, if the same
 194      symbol is already declared, may return a different decl for that
 195      name.  */
 196   tree (*pushdecl) (tree);
 197
 198   /* Returns the chain of decls so far in the current scope level.  */
 199   tree (*getdecls) (void);
 200
 201   /* Returns -1 if dwarf ATTR shouldn't be added for DECL, or the attribute
 202      value otherwise.  */
 203   int (*decl_dwarf_attribute) (const_tree, int);
 204
 205   /* Returns True if the parameter is a generic parameter decl
 206      of a generic type, e.g a template template parameter for the C++ FE.  */
 207   bool (*generic_generic_parameter_decl_p) (const_tree);
 208
 209   /* Determine if a function parameter got expanded from a
 210      function parameter pack.  */
 211   bool (*function_parm_expanded_from_pack_p) (tree, tree);
 212
 213   /* Returns the generic declaration of a generic function instantiations.  */
 214   tree (*get_generic_function_decl) (const_tree);
 215
 216   /* Returns true when we should warn for an unused global DECL.
 217      We will already have checked that it has static binding.  */
 218   bool (*warn_unused_global) (const_tree);
 219
 220   /* Perform any post compilation-proper parser cleanups and
 221      processing.  This is currently only needed for the C++ parser,
 222      which hopefully can be cleaned up so this hook is no longer
 223      necessary.  */
 224   void (*post_compilation_parsing_cleanups) (void);
 225
 226   /* True if this decl may be called via a sibcall.  */
 227   bool (*ok_for_sibcall) (const_tree);
 228
 229   /* Return a tree for the actual data of an array descriptor - or NULL_TREE
 230      if original tree is not an array descriptor.  If the second argument
 231      is true, only the TREE_TYPE is returned without generating a new tree.  */
 232   tree (*omp_array_data) (tree, bool);
 233
 234   /* True if OpenMP should regard this DECL as being a scalar which has Fortran's
 235      allocatable or pointer attribute.  */
 236   bool (*omp_is_allocatable_or_ptr) (const_tree);
 237
 238   /* Check whether this DECL belongs to a Fortran optional argument.
 239      With 'for_present_check' set to false, decls which are optional parameters
 240      themselve are returned as tree - or a NULL_TREE otherwise. Those decls are
 241      always pointers.  With 'for_present_check' set to true, the decl for
 242      checking whether an argument is present is returned; for arguments with
 243      value attribute this is the hidden argument and of BOOLEAN_TYPE.  If the
 244      decl is unrelated to optional arguments, NULL_TREE is returned.  */
 245   tree (*omp_check_optional_argument) (tree, bool);
 246
 247   /* True if OpenMP should privatize what this DECL points to rather
 248      than the DECL itself.  */
 249   bool (*omp_privatize_by_reference) (const_tree);
 250
 251   /* Return sharing kind if OpenMP sharing attribute of DECL is
 252      predetermined, OMP_CLAUSE_DEFAULT_UNSPECIFIED otherwise.  */
 253   enum omp_clause_default_kind (*omp_predetermined_sharing) (tree);
 254
 255   /* Return mapping kind if OpenMP mapping attribute of DECL is
 256      predetermined, OMP_CLAUSE_DEFAULTMAP_CATEGORY_UNSPECIFIED otherwise.  */
 257   enum omp_clause_defaultmap_kind (*omp_predetermined_mapping) (tree);
 258
 259   /* Return decl that should be reported for DEFAULT(NONE) failure
 260      diagnostics.  Usually the DECL passed in.  */
 261   tree (*omp_report_decl) (tree);
 262
 263   /* Return true if DECL's DECL_VALUE_EXPR (if any) should be
 264      disregarded in OpenMP construct, because it is going to be
 265      remapped during OpenMP lowering.  SHARED is true if DECL
 266      is going to be shared, false if it is going to be privatized.  */
 267   bool (*omp_disregard_value_expr) (tree, bool);
 268
 269   /* Return true if DECL that is shared iff SHARED is true should
 270      be put into OMP_CLAUSE_PRIVATE_DEBUG.  */
 271   bool (*omp_private_debug_clause) (tree, bool);
 272
 273   /* Return true if DECL in private clause needs
 274      OMP_CLAUSE_PRIVATE_OUTER_REF on the private clause.  */
 275   bool (*omp_private_outer_ref) (tree);
 276
 277   /* Build and return code for a default constructor for DECL in
 278      response to CLAUSE.  OUTER is corresponding outer region's
 279      variable if needed.  Return NULL if nothing to be done.  */
 280   tree (*omp_clause_default_ctor) (tree clause, tree decl, tree outer);
 281
 282   /* Build and return code for a copy constructor from SRC to DST.  */
 283   tree (*omp_clause_copy_ctor) (tree clause, tree dst, tree src);
 284
 285   /* Similarly, except use an assignment operator instead.  */
 286   tree (*omp_clause_assign_op) (tree clause, tree dst, tree src);
 287
 288   /* Build and return code for a constructor of DST that sets it to
 289      SRC + ADD.  */
 290   tree (*omp_clause_linear_ctor) (tree clause, tree dst, tree src, tree add);
 291
 292   /* Build and return code destructing DECL.  Return NULL if nothing
 293      to be done.  */
 294   tree (*omp_clause_dtor) (tree clause, tree decl);
 295
 296   /* Do language specific checking on an implicitly determined clause.  */
 297   void (*omp_finish_clause) (tree clause, gimple_seq *pre_p, bool);
 298
 299   /* Return true if DECL is a scalar variable (for the purpose of
 300      implicit firstprivatization).  */
 301   bool (*omp_scalar_p) (tree decl);
 302
 303   /* Return a pointer to the tree representing the initializer
 304      expression for the non-local variable DECL.  Return NULL if
 305      DECL is not initialized.  */
 306   tree *(*omp_get_decl_init) (tree decl);
 307
 308   /* Free any extra memory used to hold initializer information for
 309      variable declarations.  omp_get_decl_init must not be called
 310      after calling this.  */
 311   void (*omp_finish_decl_inits) (void);
 312 };
 313
 314 /* Language hooks related to LTO serialization.  */
 315
 316 struct lang_hooks_for_lto
 317 {
 318   /* Begin a new LTO section named NAME.  */
 319   void (*begin_section) (const char *name);
 320
 321   /* Write DATA of length LEN to the currently open LTO section.  BLOCK is a
 322      pointer to the dynamically allocated memory containing DATA.  The
 323      append_data function is responsible for freeing it when it is no longer
 324      needed.  */
 325   void (*append_data) (const void *data, size_t len, void *block);
 326
 327   /* End the previously begun LTO section.  */
 328   void (*end_section) (void);
 329 };
 330
 331 /* Language-specific hooks.  See langhooks-def.h for defaults.  */
 332
 333 struct lang_hooks
 334 {
 335   /* String identifying the front end and optionally language standard
 336      version, e.g. "GNU C++98".  */
 337   const char *name;
 338
 339   /* sizeof (struct lang_identifier), so make_node () creates
 340      identifier nodes long enough for the language-specific slots.  */
 341   size_t identifier_size;
 342
 343   /* Remove any parts of the tree that are used only by the FE. */
 344   void (*free_lang_data) (tree);
 345
 346   /* Determines the size of any language-specific tcc_constant,
 347      tcc_exceptional or tcc_type nodes.  Since it is called from
 348      make_node, the only information available is the tree code.
 349      Expected to die on unrecognized codes.  */
 350   size_t (*tree_size) (enum tree_code);
 351
 352   /* Return the language mask used for converting argv into a sequence
 353      of options.  */
 354   unsigned int (*option_lang_mask) (void);
 355
 356   /* Initialize variables in an options structure.  */
 357   void (*init_options_struct) (struct gcc_options *opts);
 358
 359   /* After the initialize_diagnostics hook is called, do any simple
 360      initialization needed before any calls to handle_option, other
 361      than that done by the init_options_struct hook.  */
 362   void (*init_options) (unsigned int decoded_options_count,
 363                         struct cl_decoded_option *decoded_options);
 364
 365   /* Callback used to perform language-specific initialization for the
 366      global diagnostic context structure.  */
 367   void (*initialize_diagnostics) (diagnostic_context *);
 368
 369   /* Beginning the main source file.  */
 370   void (*preprocess_main_file) (cpp_reader *, line_maps *,
 371                                 const line_map_ordinary *);
 372
 373   /* Adjust libcpp options and callbacks.  */
 374   void (*preprocess_options) (cpp_reader *);
 375
 376   /* Undefining a macro.  */
 377   void (*preprocess_undef) (cpp_reader *, location_t, cpp_hashnode *);
 378
 379   /* Observer for preprocessing stream.  */
 380   uintptr_t (*preprocess_token) (cpp_reader *, const cpp_token *, uintptr_t);
 381   /* Various flags it can return about the token.  */
 382   enum PT_flags
 383     {
 384      PT_begin_pragma = 1 << 0
 385     };
 386
 387   /* Register language-specific dumps.  */
 388   void (*register_dumps) (gcc::dump_manager *);
 389
 390   /* Return true if a warning should be given about option OPTION,
 391      which is for the wrong language, false if it should be quietly
 392      ignored.  */
 393   bool (*complain_wrong_lang_p) (const struct cl_option *option);
 394
 395   /* Handle the switch CODE, which has real type enum opt_code from
 396      options.h.  If the switch takes an argument, it is passed in ARG
 397      which points to permanent storage.  The handler is responsible for
 398      checking whether ARG is NULL, which indicates that no argument
 399      was in fact supplied.  For -f and -W switches, VALUE is 1 or 0
 400      for the positive and negative forms respectively.  HANDLERS should
 401      be passed to any recursive handle_option calls.  LOC is the
 402      location of the option.
 403
 404      Return true if the switch is valid, false if invalid.  */
 405   bool (*handle_option) (size_t code, const char *arg, HOST_WIDE_INT value,
 406                          int kind, location_t loc,
 407                          const struct cl_option_handlers *handlers);
 408
 409   /* Called when all command line options have been parsed to allow
 410      further processing and initialization
 411
 412      Should return true to indicate that a compiler back-end is
 413      not required, such as with the -E option.
 414
 415      If errorcount is nonzero after this call the compiler exits
 416      immediately and the finish hook is not called.  */
 417   bool (*post_options) (const char **);
 418
 419   /* Called after post_options to initialize the front end.  Return
 420      false to indicate that no further compilation be performed, in
 421      which case the finish hook is called immediately.  */
 422   bool (*init) (void);
 423
 424   /* Called at the end of compilation, as a finalizer.  */
 425   void (*finish) (void);
 426
 427   /* Parses the entire file.  */
 428   void (*parse_file) (void);
 429
 430   /* Determines if it's ok for a function to have no noreturn attribute.  */
 431   bool (*missing_noreturn_ok_p) (tree);
 432
 433   /* Called to obtain the alias set to be used for an expression or type.
 434      Returns -1 if the language does nothing special for it.  */
 435   alias_set_type (*get_alias_set) (tree);
 436
 437   /* Function to finish handling an incomplete decl at the end of
 438      compilation.  Default hook is does nothing.  */
 439   void (*finish_incomplete_decl) (tree);
 440
 441   /* Replace the DECL_LANG_SPECIFIC data, which may be NULL, of the
 442      DECL_NODE with a newly GC-allocated copy.  */
 443   void (*dup_lang_specific_decl) (tree);
 444
 445   /* Set the DECL_ASSEMBLER_NAME for a node.  If it is the sort of
 446      thing that the assembler should talk about, set
 447      DECL_ASSEMBLER_NAME to an appropriate IDENTIFIER_NODE.
 448      Otherwise, set it to the ERROR_MARK_NODE to ensure that the
 449      assembler does not talk about it.  */
 450   void (*set_decl_assembler_name) (tree);
 451
 452   /* Overwrite the DECL_ASSEMBLER_NAME for a node.  The name is being
 453      changed (including to or from NULL_TREE).  */
 454   void (*overwrite_decl_assembler_name) (tree, tree);
 455
 456   /* The front end can add its own statistics to -fmem-report with
 457      this hook.  It should output to stderr.  */
 458   void (*print_statistics) (void);
 459
 460   /* Called by print_tree when there is a tree of class tcc_exceptional
 461      that it doesn't know how to display.  */
 462   lang_print_tree_hook print_xnode;
 463
 464   /* Called to print language-dependent parts of tcc_decl, tcc_type,
 465      and IDENTIFIER_NODE nodes.  */
 466   lang_print_tree_hook print_decl;
 467   lang_print_tree_hook print_type;
 468   lang_print_tree_hook print_identifier;
 469
 470   /* Computes the name to use to print a declaration.  DECL is the
 471      non-NULL declaration in question.  VERBOSITY determines what
 472      information will be printed: 0: DECL_NAME, demangled as
 473      necessary.  1: and scope information.  2: and any other
 474      information that might be interesting, such as function parameter
 475      types in C++.  The name is in the internal character set and
 476      needs to be converted to the locale character set of diagnostics,
 477      or to the execution character set for strings such as
 478      __PRETTY_FUNCTION__.  */
 479   const char *(*decl_printable_name) (tree decl, int verbosity);
 480
 481   /* Computes the dwarf-2/3 name for a tree.  VERBOSITY determines what
 482      information will be printed: 0: DECL_NAME, demangled as
 483      necessary.  1: and scope information.  */
 484   const char *(*dwarf_name) (tree, int verbosity);
 485
 486   /* This compares two types for equivalence ("compatible" in C-based languages).
 487      This routine should only return 1 if it is sure.  It should not be used
 488      in contexts where erroneously returning 0 causes problems.  */
 489   int (*types_compatible_p) (tree x, tree y);
 490
 491   /* Called by report_error_function to print out function name.  */
 492   void (*print_error_function) (diagnostic_context *, const char *,
 493                                 struct diagnostic_info *);
 494
 495   /* Convert a character from the host's to the target's character
 496      set.  The character should be in what C calls the "basic source
 497      character set" (roughly, the set of characters defined by plain
 498      old ASCII).  The default is to return the character unchanged,
 499      which is correct in most circumstances.  Note that both argument
 500      and result should be sign-extended under -fsigned-char,
 501      zero-extended under -fno-signed-char.  */
 502   HOST_WIDE_INT (*to_target_charset) (HOST_WIDE_INT);
 503
 504   /* Pointers to machine-independent attribute tables, for front ends
 505      using attribs.c.  If one is NULL, it is ignored.  Respectively, a
 506      table of attributes specific to the language, a table of
 507      attributes common to two or more languages (to allow easy
 508      sharing), and a table of attributes for checking formats.  */
 509   const struct attribute_spec *attribute_table;
 510   const struct attribute_spec *common_attribute_table;
 511   const struct attribute_spec *format_attribute_table;
 512
 513   struct lang_hooks_for_tree_inlining tree_inlining;
 514
 515   struct lang_hooks_for_tree_dump tree_dump;
 516
 517   struct lang_hooks_for_decls decls;
 518
 519   struct lang_hooks_for_types types;
 520
 521   struct lang_hooks_for_lto lto;
 522
 523   /* Returns a TREE_VEC of the generic parameters of an instantiation of
 524      a generic type or decl, e.g. C++ template instantiation.  If
 525      TREE_CHAIN of the return value is set, it is an INTEGER_CST
 526      indicating how many of the elements are non-default.  */
 527   tree (*get_innermost_generic_parms) (const_tree);
 528
 529   /* Returns the TREE_VEC of arguments of an instantiation
 530      of a generic type of decl, e.g. C++ template instantiation.  */
 531   tree (*get_innermost_generic_args) (const_tree);
 532
 533   /* Determine if a tree is a function parameter pack.  */
 534   bool (*function_parameter_pack_p) (const_tree);
 535
 536   /* Perform language-specific gimplification on the argument.  Returns an
 537      enum gimplify_status, though we can't see that type here.  */
 538   int (*gimplify_expr) (tree *, gimple_seq *, gimple_seq *);
 539
 540   /* Do language specific processing in the builtin function DECL  */
 541   tree (*builtin_function) (tree decl);
 542
 543   /* Like builtin_function, but make sure the scope is the external scope.
 544      This is used to delay putting in back end builtin functions until the ISA
 545      that defines the builtin is declared via function specific target options,
 546      which can save memory for machines like the x86_64 that have multiple
 547      ISAs.  If this points to the same function as builtin_function, the
 548      backend must add all of the builtins at program initialization time.  */
 549   tree (*builtin_function_ext_scope) (tree decl);
 550
 551   /* Do language-specific processing for target-specific built-in
 552      function DECL, so that it is defined in the global scope (only)
 553      and is available without needing to be explicitly declared.
 554
 555      This is intended for targets that want to inject declarations of
 556      built-in functions into the source language (such as in response
 557      to a pragma) rather than providing them in the source language itself.  */
 558   tree (*simulate_builtin_function_decl) (tree decl);
 559
 560   /* Used to set up the tree_contains_structure array for a frontend. */
 561   void (*init_ts) (void);
 562
 563   /* Called by recompute_tree_invariant_for_addr_expr to go from EXPR
 564      to a contained expression or DECL, possibly updating *TC or *SE
 565      if in the process TREE_CONSTANT or TREE_SIDE_EFFECTS need updating.  */
 566   tree (*expr_to_decl) (tree expr, bool *tc, bool *se);
 567
 568   /* The EH personality function decl.  */
 569   tree (*eh_personality) (void);
 570
 571   /* Map a type to a runtime object to match type.  */
 572   tree (*eh_runtime_type) (tree);
 573
 574   /* If non-NULL, this is a function that returns a function decl to be
 575      executed if an unhandled exception is propagated out of a cleanup
 576      region.  For example, in C++, an exception thrown by a destructor
 577      during stack unwinding is required to result in a call to
 578      `std::terminate', so the C++ version of this function returns a
 579      FUNCTION_DECL for `std::terminate'.  */
 580   tree (*eh_protect_cleanup_actions) (void);
 581
 582   /* Return true if a stmt can fallthru.  Used by block_may_fallthru
 583      to possibly handle language trees.  */
 584   bool (*block_may_fallthru) (const_tree);
 585
 586   /* True if this language uses __cxa_end_cleanup when the ARM EABI
 587      is enabled.  */
 588   bool eh_use_cxa_end_cleanup;
 589
 590   /* True if this language requires deep unsharing of tree nodes prior to
 591      gimplification.  */
 592   bool deep_unsharing;
 593
 594   /* True if this language may use custom descriptors for nested functions
 595      instead of trampolines.  */
 596   bool custom_function_descriptors;
 597
 598   /* True if this language emits begin stmt notes.  */
 599   bool emits_begin_stmt;
 600
 601   /* Run all lang-specific selftests.  */
 602   void (*run_lang_selftests) (void);
 603
 604   /* Attempt to determine the source location of the substring.
 605      If successful, return NULL and write the source location to *OUT_LOC.
 606      Otherwise return an error message.  Error messages are intended
 607      for GCC developers (to help debugging) rather than for end-users.  */
 608   const char *(*get_substring_location) (const substring_loc &,
 609                                          location_t *out_loc);
 610
 611   /* Invoked before the early_finish debug hook is invoked.  */
 612   void (*finalize_early_debug) (void);
 613
 614   /* Whenever you add entries here, make sure you adjust langhooks-def.h
 615      and langhooks.c accordingly.  */
 616 };
 617
 618 /* Each front end provides its own.  */
 619 extern struct lang_hooks lang_hooks;
 620
 621 extern tree add_builtin_function (const char *name, tree type,
 622                                   int function_code, enum built_in_class cl,
 623                                   const char *library_name,
 624                                   tree attrs);
 625
 626 extern tree add_builtin_function_ext_scope (const char *name, tree type,
 627                                             int function_code,
 628                                             enum built_in_class cl,
 629                                             const char *library_name,
 630                                             tree attrs);
 631 extern tree simulate_builtin_function_decl (location_t, const char *, tree,
 632                                             int, const char *, tree);
 633 extern tree add_builtin_type (const char *name, tree type);
 634
 635 /* Language helper functions.  */
 636
 637 extern bool lang_GNU_C (void);
 638 extern bool lang_GNU_CXX (void);
 639 extern bool lang_GNU_Fortran (void);
 640 extern bool lang_GNU_OBJC (void);
 641
 642 #endif /* GCC_LANG_HOOKS_H */