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