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_TYPEs.  */
 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
 167 /* Language hooks related to decls and the symbol table.  */
 168
 169 struct lang_hooks_for_decls
 170 {
 171   /* Return true if we are in the global binding level.  This hook is really
 172      needed only if the language supports variable-sized types at the global
 173      level, i.e. declared outside subprograms.  */
 174   bool (*global_bindings_p) (void);
 175
 176   /* Function to add a decl to the current scope level.  Takes one
 177      argument, a decl to add.  Returns that decl, or, if the same
 178      symbol is already declared, may return a different decl for that
 179      name.  */
 180   tree (*pushdecl) (tree);
 181
 182   /* Returns the chain of decls so far in the current scope level.  */
 183   tree (*getdecls) (void);
 184
 185   /* Returns true if DECL is explicit member function.  */
 186   bool (*function_decl_explicit_p) (const_tree);
 187
 188   /* Returns true if DECL is C++11 deleted special member function.  */
 189   bool (*function_decl_deleted_p) (const_tree);
 190
 191   /* Returns 0 if DECL is NOT a C++11 defaulted special member
 192      function, 1 if it is explicitly defaulted within the class body,
 193      or 2 if it is explicitly defaulted outside the class body.  */
 194   int (*function_decl_defaulted) (const_tree);
 195
 196   /* Returns True if the parameter is a generic parameter decl
 197      of a generic type, e.g a template template parameter for the C++ FE.  */
 198   bool (*generic_generic_parameter_decl_p) (const_tree);
 199
 200   /* Determine if a function parameter got expanded from a
 201      function parameter pack.  */
 202   bool (*function_parm_expanded_from_pack_p) (tree, tree);
 203
 204   /* Returns the generic declaration of a generic function instantiations.  */
 205   tree (*get_generic_function_decl) (const_tree);
 206
 207   /* Returns true when we should warn for an unused global DECL.
 208      We will already have checked that it has static binding.  */
 209   bool (*warn_unused_global) (const_tree);
 210
 211   /* Perform any post compilation-proper parser cleanups and
 212      processing.  This is currently only needed for the C++ parser,
 213      which hopefully can be cleaned up so this hook is no longer
 214      necessary.  */
 215   void (*post_compilation_parsing_cleanups) (void);
 216
 217   /* True if this decl may be called via a sibcall.  */
 218   bool (*ok_for_sibcall) (const_tree);
 219
 220   /* True if OpenMP should privatize what this DECL points to rather
 221      than the DECL itself.  */
 222   bool (*omp_privatize_by_reference) (const_tree);
 223
 224   /* Return sharing kind if OpenMP sharing attribute of DECL is
 225      predetermined, OMP_CLAUSE_DEFAULT_UNSPECIFIED otherwise.  */
 226   enum omp_clause_default_kind (*omp_predetermined_sharing) (tree);
 227
 228   /* Return decl that should be reported for DEFAULT(NONE) failure
 229      diagnostics.  Usually the DECL passed in.  */
 230   tree (*omp_report_decl) (tree);
 231
 232   /* Return true if DECL's DECL_VALUE_EXPR (if any) should be
 233      disregarded in OpenMP construct, because it is going to be
 234      remapped during OpenMP lowering.  SHARED is true if DECL
 235      is going to be shared, false if it is going to be privatized.  */
 236   bool (*omp_disregard_value_expr) (tree, bool);
 237
 238   /* Return true if DECL that is shared iff SHARED is true should
 239      be put into OMP_CLAUSE_PRIVATE_DEBUG.  */
 240   bool (*omp_private_debug_clause) (tree, bool);
 241
 242   /* Return true if DECL in private clause needs
 243      OMP_CLAUSE_PRIVATE_OUTER_REF on the private clause.  */
 244   bool (*omp_private_outer_ref) (tree);
 245
 246   /* Build and return code for a default constructor for DECL in
 247      response to CLAUSE.  OUTER is corresponding outer region's
 248      variable if needed.  Return NULL if nothing to be done.  */
 249   tree (*omp_clause_default_ctor) (tree clause, tree decl, tree outer);
 250
 251   /* Build and return code for a copy constructor from SRC to DST.  */
 252   tree (*omp_clause_copy_ctor) (tree clause, tree dst, tree src);
 253
 254   /* Similarly, except use an assignment operator instead.  */
 255   tree (*omp_clause_assign_op) (tree clause, tree dst, tree src);
 256
 257   /* Build and return code for a constructor of DST that sets it to
 258      SRC + ADD.  */
 259   tree (*omp_clause_linear_ctor) (tree clause, tree dst, tree src, tree add);
 260
 261   /* Build and return code destructing DECL.  Return NULL if nothing
 262      to be done.  */
 263   tree (*omp_clause_dtor) (tree clause, tree decl);
 264
 265   /* Do language specific checking on an implicitly determined clause.  */
 266   void (*omp_finish_clause) (tree clause, gimple_seq *pre_p);
 267 };
 268
 269 /* Language hooks related to LTO serialization.  */
 270
 271 struct lang_hooks_for_lto
 272 {
 273   /* Begin a new LTO section named NAME.  */
 274   void (*begin_section) (const char *name);
 275
 276   /* Write DATA of length LEN to the currently open LTO section.  BLOCK is a
 277      pointer to the dynamically allocated memory containing DATA.  The
 278      append_data function is responsible for freeing it when it is no longer
 279      needed.  */
 280   void (*append_data) (const void *data, size_t len, void *block);
 281
 282   /* End the previously begun LTO section.  */
 283   void (*end_section) (void);
 284 };
 285
 286 /* Language-specific hooks.  See langhooks-def.h for defaults.  */
 287
 288 struct lang_hooks
 289 {
 290   /* String identifying the front end and optionally language standard
 291      version, e.g. "GNU C++98" or "GNU Java".  */
 292   const char *name;
 293
 294   /* sizeof (struct lang_identifier), so make_node () creates
 295      identifier nodes long enough for the language-specific slots.  */
 296   size_t identifier_size;
 297
 298   /* Remove any parts of the tree that are used only by the FE. */
 299   void (*free_lang_data) (tree);
 300
 301   /* Determines the size of any language-specific tcc_constant or
 302      tcc_exceptional nodes.  Since it is called from make_node, the
 303      only information available is the tree code.  Expected to die
 304      on unrecognized codes.  */
 305   size_t (*tree_size) (enum tree_code);
 306
 307   /* Return the language mask used for converting argv into a sequence
 308      of options.  */
 309   unsigned int (*option_lang_mask) (void);
 310
 311   /* Initialize variables in an options structure.  */
 312   void (*init_options_struct) (struct gcc_options *opts);
 313
 314   /* After the initialize_diagnostics hook is called, do any simple
 315      initialization needed before any calls to handle_option, other
 316      than that done by the init_options_struct hook.  */
 317   void (*init_options) (unsigned int decoded_options_count,
 318                         struct cl_decoded_option *decoded_options);
 319
 320   /* Callback used to perform language-specific initialization for the
 321      global diagnostic context structure.  */
 322   void (*initialize_diagnostics) (diagnostic_context *);
 323
 324   /* Return true if a warning should be given about option OPTION,
 325      which is for the wrong language, false if it should be quietly
 326      ignored.  */
 327   bool (*complain_wrong_lang_p) (const struct cl_option *option);
 328
 329   /* Handle the switch CODE, which has real type enum opt_code from
 330      options.h.  If the switch takes an argument, it is passed in ARG
 331      which points to permanent storage.  The handler is responsible for
 332      checking whether ARG is NULL, which indicates that no argument
 333      was in fact supplied.  For -f and -W switches, VALUE is 1 or 0
 334      for the positive and negative forms respectively.  HANDLERS should
 335      be passed to any recursive handle_option calls.  LOC is the
 336      location of the option.
 337
 338      Return true if the switch is valid, false if invalid.  */
 339   bool (*handle_option) (size_t code, const char *arg, int value, int kind,
 340                          location_t loc,
 341                          const struct cl_option_handlers *handlers);
 342
 343   /* Called when all command line options have been parsed to allow
 344      further processing and initialization
 345
 346      Should return true to indicate that a compiler back-end is
 347      not required, such as with the -E option.
 348
 349      If errorcount is nonzero after this call the compiler exits
 350      immediately and the finish hook is not called.  */
 351   bool (*post_options) (const char **);
 352
 353   /* Called after post_options to initialize the front end.  Return
 354      false to indicate that no further compilation be performed, in
 355      which case the finish hook is called immediately.  */
 356   bool (*init) (void);
 357
 358   /* Called at the end of compilation, as a finalizer.  */
 359   void (*finish) (void);
 360
 361   /* Parses the entire file.  */
 362   void (*parse_file) (void);
 363
 364   /* Determines if it's ok for a function to have no noreturn attribute.  */
 365   bool (*missing_noreturn_ok_p) (tree);
 366
 367   /* Called to obtain the alias set to be used for an expression or type.
 368      Returns -1 if the language does nothing special for it.  */
 369   alias_set_type (*get_alias_set) (tree);
 370
 371   /* Function to finish handling an incomplete decl at the end of
 372      compilation.  Default hook is does nothing.  */
 373   void (*finish_incomplete_decl) (tree);
 374
 375   /* Replace the DECL_LANG_SPECIFIC data, which may be NULL, of the
 376      DECL_NODE with a newly GC-allocated copy.  */
 377   void (*dup_lang_specific_decl) (tree);
 378
 379   /* Set the DECL_ASSEMBLER_NAME for a node.  If it is the sort of
 380      thing that the assembler should talk about, set
 381      DECL_ASSEMBLER_NAME to an appropriate IDENTIFIER_NODE.
 382      Otherwise, set it to the ERROR_MARK_NODE to ensure that the
 383      assembler does not talk about it.  */
 384   void (*set_decl_assembler_name) (tree);
 385
 386   /* The front end can add its own statistics to -fmem-report with
 387      this hook.  It should output to stderr.  */
 388   void (*print_statistics) (void);
 389
 390   /* Called by print_tree when there is a tree of class tcc_exceptional
 391      that it doesn't know how to display.  */
 392   lang_print_tree_hook print_xnode;
 393
 394   /* Called to print language-dependent parts of tcc_decl, tcc_type,
 395      and IDENTIFIER_NODE nodes.  */
 396   lang_print_tree_hook print_decl;
 397   lang_print_tree_hook print_type;
 398   lang_print_tree_hook print_identifier;
 399
 400   /* Computes the name to use to print a declaration.  DECL is the
 401      non-NULL declaration in question.  VERBOSITY determines what
 402      information will be printed: 0: DECL_NAME, demangled as
 403      necessary.  1: and scope information.  2: and any other
 404      information that might be interesting, such as function parameter
 405      types in C++.  The name is in the internal character set and
 406      needs to be converted to the locale character set of diagnostics,
 407      or to the execution character set for strings such as
 408      __PRETTY_FUNCTION__.  */
 409   const char *(*decl_printable_name) (tree decl, int verbosity);
 410
 411   /* Computes the dwarf-2/3 name for a tree.  VERBOSITY determines what
 412      information will be printed: 0: DECL_NAME, demangled as
 413      necessary.  1: and scope information.  */
 414   const char *(*dwarf_name) (tree, int verbosity);
 415
 416   /* This compares two types for equivalence ("compatible" in C-based languages).
 417      This routine should only return 1 if it is sure.  It should not be used
 418      in contexts where erroneously returning 0 causes problems.  */
 419   int (*types_compatible_p) (tree x, tree y);
 420
 421   /* Called by report_error_function to print out function name.  */
 422   void (*print_error_function) (diagnostic_context *, const char *,
 423                                 struct diagnostic_info *);
 424
 425   /* Convert a character from the host's to the target's character
 426      set.  The character should be in what C calls the "basic source
 427      character set" (roughly, the set of characters defined by plain
 428      old ASCII).  The default is to return the character unchanged,
 429      which is correct in most circumstances.  Note that both argument
 430      and result should be sign-extended under -fsigned-char,
 431      zero-extended under -fno-signed-char.  */
 432   HOST_WIDE_INT (*to_target_charset) (HOST_WIDE_INT);
 433
 434   /* Pointers to machine-independent attribute tables, for front ends
 435      using attribs.c.  If one is NULL, it is ignored.  Respectively, a
 436      table of attributes specific to the language, a table of
 437      attributes common to two or more languages (to allow easy
 438      sharing), and a table of attributes for checking formats.  */
 439   const struct attribute_spec *attribute_table;
 440   const struct attribute_spec *common_attribute_table;
 441   const struct attribute_spec *format_attribute_table;
 442
 443   struct lang_hooks_for_tree_inlining tree_inlining;
 444
 445   struct lang_hooks_for_tree_dump tree_dump;
 446
 447   struct lang_hooks_for_decls decls;
 448
 449   struct lang_hooks_for_types types;
 450
 451   struct lang_hooks_for_lto lto;
 452
 453   /* Returns a TREE_VEC of the generic parameters of an instantiation of
 454      a generic type or decl, e.g. C++ template instantiation.  If
 455      TREE_CHAIN of the return value is set, it is an INTEGER_CST
 456      indicating how many of the elements are non-default.  */
 457   tree (*get_innermost_generic_parms) (const_tree);
 458
 459   /* Returns the TREE_VEC of arguments of an instantiation
 460      of a generic type of decl, e.g. C++ template instantiation.  */
 461   tree (*get_innermost_generic_args) (const_tree);
 462
 463   /* Determine if a tree is a function parameter pack.  */
 464   bool (*function_parameter_pack_p) (const_tree);
 465
 466   /* Perform language-specific gimplification on the argument.  Returns an
 467      enum gimplify_status, though we can't see that type here.  */
 468   int (*gimplify_expr) (tree *, gimple_seq *, gimple_seq *);
 469
 470   /* Do language specific processing in the builtin function DECL  */
 471   tree (*builtin_function) (tree decl);
 472
 473   /* Like builtin_function, but make sure the scope is the external scope.
 474      This is used to delay putting in back end builtin functions until the ISA
 475      that defines the builtin is declared via function specific target options,
 476      which can save memory for machines like the x86_64 that have multiple
 477      ISAs.  If this points to the same function as builtin_function, the
 478      backend must add all of the builtins at program initialization time.  */
 479   tree (*builtin_function_ext_scope) (tree decl);
 480
 481   /* Used to set up the tree_contains_structure array for a frontend. */
 482   void (*init_ts) (void);
 483
 484   /* Called by recompute_tree_invariant_for_addr_expr to go from EXPR
 485      to a contained expression or DECL, possibly updating *TC or *SE
 486      if in the process TREE_CONSTANT or TREE_SIDE_EFFECTS need updating.  */
 487   tree (*expr_to_decl) (tree expr, bool *tc, bool *se);
 488
 489   /* The EH personality function decl.  */
 490   tree (*eh_personality) (void);
 491
 492   /* Map a type to a runtime object to match type.  */
 493   tree (*eh_runtime_type) (tree);
 494
 495   /* If non-NULL, this is a function that returns a function decl to be
 496      executed if an unhandled exception is propagated out of a cleanup
 497      region.  For example, in C++, an exception thrown by a destructor
 498      during stack unwinding is required to result in a call to
 499      `std::terminate', so the C++ version of this function returns a
 500      FUNCTION_DECL for `std::terminate'.  */
 501   tree (*eh_protect_cleanup_actions) (void);
 502
 503   /* Return true if a stmt can fallthru.  Used by block_may_fallthru
 504      to possibly handle language trees.  */
 505   bool (*block_may_fallthru) (const_tree);
 506
 507   /* True if this language uses __cxa_end_cleanup when the ARM EABI
 508      is enabled.  */
 509   bool eh_use_cxa_end_cleanup;
 510
 511   /* True if this language requires deep unsharing of tree nodes prior to
 512      gimplification.  */
 513   bool deep_unsharing;
 514
 515   /* True if this language may use custom descriptors for nested functions
 516      instead of trampolines.  */
 517   bool custom_function_descriptors;
 518
 519   /* Run all lang-specific selftests.  */
 520   void (*run_lang_selftests) (void);
 521
 522   /* Attempt to determine the source location of the substring.
 523      If successful, return NULL and write the source location to *OUT_LOC.
 524      Otherwise return an error message.  Error messages are intended
 525      for GCC developers (to help debugging) rather than for end-users.  */
 526   const char *(*get_substring_location) (const substring_loc &,
 527                                          location_t *out_loc);
 528
 529   /* Whenever you add entries here, make sure you adjust langhooks-def.h
 530      and langhooks.c accordingly.  */
 531 };
 532
 533 /* Each front end provides its own.  */
 534 extern struct lang_hooks lang_hooks;
 535
 536 extern tree add_builtin_function (const char *name, tree type,
 537                                   int function_code, enum built_in_class cl,
 538                                   const char *library_name,
 539                                   tree attrs);
 540
 541 extern tree add_builtin_function_ext_scope (const char *name, tree type,
 542                                             int function_code,
 543                                             enum built_in_class cl,
 544                                             const char *library_name,
 545                                             tree attrs);
 546 extern tree add_builtin_type (const char *name, tree type);
 547
 548 /* Language helper functions.  */
 549
 550 extern bool lang_GNU_C (void);
 551 extern bool lang_GNU_CXX (void);
 552 extern bool lang_GNU_Fortran (void);
 553 extern bool lang_GNU_OBJC (void);
 554
 555 #endif /* GCC_LANG_HOOKS_H */