gcc/langhooks.h

   1 /* The lang_hooks data structure.
   2    Copyright (C) 2001-2017 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   /* Returns a tree for the unit size of T excluding tail padding that
 171      might be used by objects inheriting from T.  */
 172   tree (*unit_size_without_reusable_padding) (tree);
 173 };
 174
 175 /* Language hooks related to decls and the symbol table.  */
 176
 177 struct lang_hooks_for_decls
 178 {
 179   /* Return true if we are in the global binding level.  This hook is really
 180      needed only if the language supports variable-sized types at the global
 181      level, i.e. declared outside subprograms.  */
 182   bool (*global_bindings_p) (void);
 183
 184   /* Function to add a decl to the current scope level.  Takes one
 185      argument, a decl to add.  Returns that decl, or, if the same
 186      symbol is already declared, may return a different decl for that
 187      name.  */
 188   tree (*pushdecl) (tree);
 189
 190   /* Returns the chain of decls so far in the current scope level.  */
 191   tree (*getdecls) (void);
 192
 193   /* Returns -1 if dwarf ATTR shouldn't be added for DECL, or the attribute
 194      value otherwise.  */
 195   int (*decl_dwarf_attribute) (const_tree, int);
 196
 197   /* Returns True if the parameter is a generic parameter decl
 198      of a generic type, e.g a template template parameter for the C++ FE.  */
 199   bool (*generic_generic_parameter_decl_p) (const_tree);
 200
 201   /* Determine if a function parameter got expanded from a
 202      function parameter pack.  */
 203   bool (*function_parm_expanded_from_pack_p) (tree, tree);
 204
 205   /* Returns the generic declaration of a generic function instantiations.  */
 206   tree (*get_generic_function_decl) (const_tree);
 207
 208   /* Returns true when we should warn for an unused global DECL.
 209      We will already have checked that it has static binding.  */
 210   bool (*warn_unused_global) (const_tree);
 211
 212   /* Perform any post compilation-proper parser cleanups and
 213      processing.  This is currently only needed for the C++ parser,
 214      which hopefully can be cleaned up so this hook is no longer
 215      necessary.  */
 216   void (*post_compilation_parsing_cleanups) (void);
 217
 218   /* True if this decl may be called via a sibcall.  */
 219   bool (*ok_for_sibcall) (const_tree);
 220
 221   /* True if OpenMP should privatize what this DECL points to rather
 222      than the DECL itself.  */
 223   bool (*omp_privatize_by_reference) (const_tree);
 224
 225   /* Return sharing kind if OpenMP sharing attribute of DECL is
 226      predetermined, OMP_CLAUSE_DEFAULT_UNSPECIFIED otherwise.  */
 227   enum omp_clause_default_kind (*omp_predetermined_sharing) (tree);
 228
 229   /* Return decl that should be reported for DEFAULT(NONE) failure
 230      diagnostics.  Usually the DECL passed in.  */
 231   tree (*omp_report_decl) (tree);
 232
 233   /* Return true if DECL's DECL_VALUE_EXPR (if any) should be
 234      disregarded in OpenMP construct, because it is going to be
 235      remapped during OpenMP lowering.  SHARED is true if DECL
 236      is going to be shared, false if it is going to be privatized.  */
 237   bool (*omp_disregard_value_expr) (tree, bool);
 238
 239   /* Return true if DECL that is shared iff SHARED is true should
 240      be put into OMP_CLAUSE_PRIVATE_DEBUG.  */
 241   bool (*omp_private_debug_clause) (tree, bool);
 242
 243   /* Return true if DECL in private clause needs
 244      OMP_CLAUSE_PRIVATE_OUTER_REF on the private clause.  */
 245   bool (*omp_private_outer_ref) (tree);
 246
 247   /* Build and return code for a default constructor for DECL in
 248      response to CLAUSE.  OUTER is corresponding outer region's
 249      variable if needed.  Return NULL if nothing to be done.  */
 250   tree (*omp_clause_default_ctor) (tree clause, tree decl, tree outer);
 251
 252   /* Build and return code for a copy constructor from SRC to DST.  */
 253   tree (*omp_clause_copy_ctor) (tree clause, tree dst, tree src);
 254
 255   /* Similarly, except use an assignment operator instead.  */
 256   tree (*omp_clause_assign_op) (tree clause, tree dst, tree src);
 257
 258   /* Build and return code for a constructor of DST that sets it to
 259      SRC + ADD.  */
 260   tree (*omp_clause_linear_ctor) (tree clause, tree dst, tree src, tree add);
 261
 262   /* Build and return code destructing DECL.  Return NULL if nothing
 263      to be done.  */
 264   tree (*omp_clause_dtor) (tree clause, tree decl);
 265
 266   /* Do language specific checking on an implicitly determined clause.  */
 267   void (*omp_finish_clause) (tree clause, gimple_seq *pre_p);
 268
 269   /* Return true if DECL is a scalar variable (for the purpose of
 270      implicit firstprivatization).  */
 271   bool (*omp_scalar_p) (tree decl);
 272 };
 273
 274 /* Language hooks related to LTO serialization.  */
 275
 276 struct lang_hooks_for_lto
 277 {
 278   /* Begin a new LTO section named NAME.  */
 279   void (*begin_section) (const char *name);
 280
 281   /* Write DATA of length LEN to the currently open LTO section.  BLOCK is a
 282      pointer to the dynamically allocated memory containing DATA.  The
 283      append_data function is responsible for freeing it when it is no longer
 284      needed.  */
 285   void (*append_data) (const void *data, size_t len, void *block);
 286
 287   /* End the previously begun LTO section.  */
 288   void (*end_section) (void);
 289 };
 290
 291 /* Language-specific hooks.  See langhooks-def.h for defaults.  */
 292
 293 struct lang_hooks
 294 {
 295   /* String identifying the front end and optionally language standard
 296      version, e.g. "GNU C++98" or "GNU Java".  */
 297   const char *name;
 298
 299   /* sizeof (struct lang_identifier), so make_node () creates
 300      identifier nodes long enough for the language-specific slots.  */
 301   size_t identifier_size;
 302
 303   /* Remove any parts of the tree that are used only by the FE. */
 304   void (*free_lang_data) (tree);
 305
 306   /* Determines the size of any language-specific tcc_constant or
 307      tcc_exceptional nodes.  Since it is called from make_node, the
 308      only information available is the tree code.  Expected to die
 309      on unrecognized codes.  */
 310   size_t (*tree_size) (enum tree_code);
 311
 312   /* Return the language mask used for converting argv into a sequence
 313      of options.  */
 314   unsigned int (*option_lang_mask) (void);
 315
 316   /* Initialize variables in an options structure.  */
 317   void (*init_options_struct) (struct gcc_options *opts);
 318
 319   /* After the initialize_diagnostics hook is called, do any simple
 320      initialization needed before any calls to handle_option, other
 321      than that done by the init_options_struct hook.  */
 322   void (*init_options) (unsigned int decoded_options_count,
 323                         struct cl_decoded_option *decoded_options);
 324
 325   /* Callback used to perform language-specific initialization for the
 326      global diagnostic context structure.  */
 327   void (*initialize_diagnostics) (diagnostic_context *);
 328
 329   /* Return true if a warning should be given about option OPTION,
 330      which is for the wrong language, false if it should be quietly
 331      ignored.  */
 332   bool (*complain_wrong_lang_p) (const struct cl_option *option);
 333
 334   /* Handle the switch CODE, which has real type enum opt_code from
 335      options.h.  If the switch takes an argument, it is passed in ARG
 336      which points to permanent storage.  The handler is responsible for
 337      checking whether ARG is NULL, which indicates that no argument
 338      was in fact supplied.  For -f and -W switches, VALUE is 1 or 0
 339      for the positive and negative forms respectively.  HANDLERS should
 340      be passed to any recursive handle_option calls.  LOC is the
 341      location of the option.
 342
 343      Return true if the switch is valid, false if invalid.  */
 344   bool (*handle_option) (size_t code, const char *arg, int value, int kind,
 345                          location_t loc,
 346                          const struct cl_option_handlers *handlers);
 347
 348   /* Called when all command line options have been parsed to allow
 349      further processing and initialization
 350
 351      Should return true to indicate that a compiler back-end is
 352      not required, such as with the -E option.
 353
 354      If errorcount is nonzero after this call the compiler exits
 355      immediately and the finish hook is not called.  */
 356   bool (*post_options) (const char **);
 357
 358   /* Called after post_options to initialize the front end.  Return
 359      false to indicate that no further compilation be performed, in
 360      which case the finish hook is called immediately.  */
 361   bool (*init) (void);
 362
 363   /* Called at the end of compilation, as a finalizer.  */
 364   void (*finish) (void);
 365
 366   /* Parses the entire file.  */
 367   void (*parse_file) (void);
 368
 369   /* Determines if it's ok for a function to have no noreturn attribute.  */
 370   bool (*missing_noreturn_ok_p) (tree);
 371
 372   /* Called to obtain the alias set to be used for an expression or type.
 373      Returns -1 if the language does nothing special for it.  */
 374   alias_set_type (*get_alias_set) (tree);
 375
 376   /* Function to finish handling an incomplete decl at the end of
 377      compilation.  Default hook is does nothing.  */
 378   void (*finish_incomplete_decl) (tree);
 379
 380   /* Replace the DECL_LANG_SPECIFIC data, which may be NULL, of the
 381      DECL_NODE with a newly GC-allocated copy.  */
 382   void (*dup_lang_specific_decl) (tree);
 383
 384   /* Set the DECL_ASSEMBLER_NAME for a node.  If it is the sort of
 385      thing that the assembler should talk about, set
 386      DECL_ASSEMBLER_NAME to an appropriate IDENTIFIER_NODE.
 387      Otherwise, set it to the ERROR_MARK_NODE to ensure that the
 388      assembler does not talk about it.  */
 389   void (*set_decl_assembler_name) (tree);
 390
 391   /* The front end can add its own statistics to -fmem-report with
 392      this hook.  It should output to stderr.  */
 393   void (*print_statistics) (void);
 394
 395   /* Called by print_tree when there is a tree of class tcc_exceptional
 396      that it doesn't know how to display.  */
 397   lang_print_tree_hook print_xnode;
 398
 399   /* Called to print language-dependent parts of tcc_decl, tcc_type,
 400      and IDENTIFIER_NODE nodes.  */
 401   lang_print_tree_hook print_decl;
 402   lang_print_tree_hook print_type;
 403   lang_print_tree_hook print_identifier;
 404
 405   /* Computes the name to use to print a declaration.  DECL is the
 406      non-NULL declaration in question.  VERBOSITY determines what
 407      information will be printed: 0: DECL_NAME, demangled as
 408      necessary.  1: and scope information.  2: and any other
 409      information that might be interesting, such as function parameter
 410      types in C++.  The name is in the internal character set and
 411      needs to be converted to the locale character set of diagnostics,
 412      or to the execution character set for strings such as
 413      __PRETTY_FUNCTION__.  */
 414   const char *(*decl_printable_name) (tree decl, int verbosity);
 415
 416   /* Computes the dwarf-2/3 name for a tree.  VERBOSITY determines what
 417      information will be printed: 0: DECL_NAME, demangled as
 418      necessary.  1: and scope information.  */
 419   const char *(*dwarf_name) (tree, int verbosity);
 420
 421   /* This compares two types for equivalence ("compatible" in C-based languages).
 422      This routine should only return 1 if it is sure.  It should not be used
 423      in contexts where erroneously returning 0 causes problems.  */
 424   int (*types_compatible_p) (tree x, tree y);
 425
 426   /* Called by report_error_function to print out function name.  */
 427   void (*print_error_function) (diagnostic_context *, const char *,
 428                                 struct diagnostic_info *);
 429
 430   /* Convert a character from the host's to the target's character
 431      set.  The character should be in what C calls the "basic source
 432      character set" (roughly, the set of characters defined by plain
 433      old ASCII).  The default is to return the character unchanged,
 434      which is correct in most circumstances.  Note that both argument
 435      and result should be sign-extended under -fsigned-char,
 436      zero-extended under -fno-signed-char.  */
 437   HOST_WIDE_INT (*to_target_charset) (HOST_WIDE_INT);
 438
 439   /* Pointers to machine-independent attribute tables, for front ends
 440      using attribs.c.  If one is NULL, it is ignored.  Respectively, a
 441      table of attributes specific to the language, a table of
 442      attributes common to two or more languages (to allow easy
 443      sharing), and a table of attributes for checking formats.  */
 444   const struct attribute_spec *attribute_table;
 445   const struct attribute_spec *common_attribute_table;
 446   const struct attribute_spec *format_attribute_table;
 447
 448   struct lang_hooks_for_tree_inlining tree_inlining;
 449
 450   struct lang_hooks_for_tree_dump tree_dump;
 451
 452   struct lang_hooks_for_decls decls;
 453
 454   struct lang_hooks_for_types types;
 455
 456   struct lang_hooks_for_lto lto;
 457
 458   /* Returns a TREE_VEC of the generic parameters of an instantiation of
 459      a generic type or decl, e.g. C++ template instantiation.  If
 460      TREE_CHAIN of the return value is set, it is an INTEGER_CST
 461      indicating how many of the elements are non-default.  */
 462   tree (*get_innermost_generic_parms) (const_tree);
 463
 464   /* Returns the TREE_VEC of arguments of an instantiation
 465      of a generic type of decl, e.g. C++ template instantiation.  */
 466   tree (*get_innermost_generic_args) (const_tree);
 467
 468   /* Determine if a tree is a function parameter pack.  */
 469   bool (*function_parameter_pack_p) (const_tree);
 470
 471   /* Perform language-specific gimplification on the argument.  Returns an
 472      enum gimplify_status, though we can't see that type here.  */
 473   int (*gimplify_expr) (tree *, gimple_seq *, gimple_seq *);
 474
 475   /* Do language specific processing in the builtin function DECL  */
 476   tree (*builtin_function) (tree decl);
 477
 478   /* Like builtin_function, but make sure the scope is the external scope.
 479      This is used to delay putting in back end builtin functions until the ISA
 480      that defines the builtin is declared via function specific target options,
 481      which can save memory for machines like the x86_64 that have multiple
 482      ISAs.  If this points to the same function as builtin_function, the
 483      backend must add all of the builtins at program initialization time.  */
 484   tree (*builtin_function_ext_scope) (tree decl);
 485
 486   /* Used to set up the tree_contains_structure array for a frontend. */
 487   void (*init_ts) (void);
 488
 489   /* Called by recompute_tree_invariant_for_addr_expr to go from EXPR
 490      to a contained expression or DECL, possibly updating *TC or *SE
 491      if in the process TREE_CONSTANT or TREE_SIDE_EFFECTS need updating.  */
 492   tree (*expr_to_decl) (tree expr, bool *tc, bool *se);
 493
 494   /* The EH personality function decl.  */
 495   tree (*eh_personality) (void);
 496
 497   /* Map a type to a runtime object to match type.  */
 498   tree (*eh_runtime_type) (tree);
 499
 500   /* If non-NULL, this is a function that returns a function decl to be
 501      executed if an unhandled exception is propagated out of a cleanup
 502      region.  For example, in C++, an exception thrown by a destructor
 503      during stack unwinding is required to result in a call to
 504      `std::terminate', so the C++ version of this function returns a
 505      FUNCTION_DECL for `std::terminate'.  */
 506   tree (*eh_protect_cleanup_actions) (void);
 507
 508   /* Return true if a stmt can fallthru.  Used by block_may_fallthru
 509      to possibly handle language trees.  */
 510   bool (*block_may_fallthru) (const_tree);
 511
 512   /* True if this language uses __cxa_end_cleanup when the ARM EABI
 513      is enabled.  */
 514   bool eh_use_cxa_end_cleanup;
 515
 516   /* True if this language requires deep unsharing of tree nodes prior to
 517      gimplification.  */
 518   bool deep_unsharing;
 519
 520   /* True if this language may use custom descriptors for nested functions
 521      instead of trampolines.  */
 522   bool custom_function_descriptors;
 523
 524   /* Run all lang-specific selftests.  */
 525   void (*run_lang_selftests) (void);
 526
 527   /* Attempt to determine the source location of the substring.
 528      If successful, return NULL and write the source location to *OUT_LOC.
 529      Otherwise return an error message.  Error messages are intended
 530      for GCC developers (to help debugging) rather than for end-users.  */
 531   const char *(*get_substring_location) (const substring_loc &,
 532                                          location_t *out_loc);
 533
 534   /* Whenever you add entries here, make sure you adjust langhooks-def.h
 535      and langhooks.c accordingly.  */
 536 };
 537
 538 /* Each front end provides its own.  */
 539 extern struct lang_hooks lang_hooks;
 540
 541 extern tree add_builtin_function (const char *name, tree type,
 542                                   int function_code, enum built_in_class cl,
 543                                   const char *library_name,
 544                                   tree attrs);
 545
 546 extern tree add_builtin_function_ext_scope (const char *name, tree type,
 547                                             int function_code,
 548                                             enum built_in_class cl,
 549                                             const char *library_name,
 550                                             tree attrs);
 551 extern tree add_builtin_type (const char *name, tree type);
 552
 553 /* Language helper functions.  */
 554
 555 extern bool lang_GNU_C (void);
 556 extern bool lang_GNU_CXX (void);
 557 extern bool lang_GNU_Fortran (void);
 558 extern bool lang_GNU_OBJC (void);
 559
 560 #endif /* GCC_LANG_HOOKS_H */