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