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      1 /* Definitions for C parsing and type checking.
      2    Copyright (C) 1987-2013 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 it under
      7 the terms of the GNU General Public License as published by the Free
      8 Software Foundation; either version 3, or (at your option) any later
      9 version.
     10 
     11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
     12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
     13 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
     14 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_C_TREE_H
     21 #define GCC_C_TREE_H
     22 
     23 #include "c-family/c-common.h"
     24 #include "diagnostic.h"
     25 
     26 /* struct lang_identifier is private to c-decl.c, but langhooks.c needs to
     27    know how big it is.  This is sanity-checked in c-decl.c.  */
     28 #define C_SIZEOF_STRUCT_LANG_IDENTIFIER \
     29   (sizeof (struct c_common_identifier) + 3 * sizeof (void *))
     30 
     31 /* In a RECORD_TYPE or UNION_TYPE, nonzero if any component is read-only.  */
     32 #define C_TYPE_FIELDS_READONLY(TYPE) TREE_LANG_FLAG_1 (TYPE)
     33 
     34 /* In a RECORD_TYPE or UNION_TYPE, nonzero if any component is volatile.  */
     35 #define C_TYPE_FIELDS_VOLATILE(TYPE) TREE_LANG_FLAG_2 (TYPE)
     36 
     37 /* In a RECORD_TYPE or UNION_TYPE or ENUMERAL_TYPE
     38    nonzero if the definition of the type has already started.  */
     39 #define C_TYPE_BEING_DEFINED(TYPE) TYPE_LANG_FLAG_0 (TYPE)
     40 
     41 /* In an incomplete RECORD_TYPE or UNION_TYPE, a list of variable
     42    declarations whose type would be completed by completing that type.  */
     43 #define C_TYPE_INCOMPLETE_VARS(TYPE) TYPE_VFIELD (TYPE)
     44 
     45 /* In an IDENTIFIER_NODE, nonzero if this identifier is actually a
     46    keyword.  C_RID_CODE (node) is then the RID_* value of the keyword,
     47    and C_RID_YYCODE is the token number wanted by Yacc.  */
     48 #define C_IS_RESERVED_WORD(ID) TREE_LANG_FLAG_0 (ID)
     49 
     50 /* Record whether a type or decl was written with nonconstant size.
     51    Note that TYPE_SIZE may have simplified to a constant.  */
     52 #define C_TYPE_VARIABLE_SIZE(TYPE) TYPE_LANG_FLAG_1 (TYPE)
     53 #define C_DECL_VARIABLE_SIZE(TYPE) DECL_LANG_FLAG_0 (TYPE)
     54 
     55 /* Record whether a type is defined inside a struct or union type.
     56    This is used for -Wc++-compat. */
     57 #define C_TYPE_DEFINED_IN_STRUCT(TYPE) TYPE_LANG_FLAG_2 (TYPE)
     58 
     59 /* Record whether a typedef for type `int' was actually `signed int'.  */
     60 #define C_TYPEDEF_EXPLICITLY_SIGNED(EXP) DECL_LANG_FLAG_1 (EXP)
     61 
     62 /* For a FUNCTION_DECL, nonzero if it was defined without an explicit
     63    return type.  */
     64 #define C_FUNCTION_IMPLICIT_INT(EXP) DECL_LANG_FLAG_1 (EXP)
     65 
     66 /* For a FUNCTION_DECL, nonzero if it was an implicit declaration.  */
     67 #define C_DECL_IMPLICIT(EXP) DECL_LANG_FLAG_2 (EXP)
     68 
     69 /* For FUNCTION_DECLs, evaluates true if the decl is built-in but has
     70    been declared.  */
     71 #define C_DECL_DECLARED_BUILTIN(EXP)		\
     72   DECL_LANG_FLAG_3 (FUNCTION_DECL_CHECK (EXP))
     73 
     74 /* For FUNCTION_DECLs, evaluates true if the decl is built-in, has a
     75    built-in prototype and does not have a non-built-in prototype.  */
     76 #define C_DECL_BUILTIN_PROTOTYPE(EXP)		\
     77   DECL_LANG_FLAG_6 (FUNCTION_DECL_CHECK (EXP))
     78 
     79 /* Record whether a decl was declared register.  This is strictly a
     80    front-end flag, whereas DECL_REGISTER is used for code generation;
     81    they may differ for structures with volatile fields.  */
     82 #define C_DECL_REGISTER(EXP) DECL_LANG_FLAG_4 (EXP)
     83 
     84 /* Record whether a decl was used in an expression anywhere except an
     85    unevaluated operand of sizeof / typeof / alignof.  This is only
     86    used for functions declared static but not defined, though outside
     87    sizeof and typeof it is set for other function decls as well.  */
     88 #define C_DECL_USED(EXP) DECL_LANG_FLAG_5 (FUNCTION_DECL_CHECK (EXP))
     89 
     90 /* Record whether a variable has been declared threadprivate by
     91    #pragma omp threadprivate.  */
     92 #define C_DECL_THREADPRIVATE_P(DECL) DECL_LANG_FLAG_3 (VAR_DECL_CHECK (DECL))
     93 
     94 /* Nonzero for a decl which either doesn't exist or isn't a prototype.
     95    N.B. Could be simplified if all built-in decls had complete prototypes
     96    (but this is presently difficult because some of them need FILE*).  */
     97 #define C_DECL_ISNT_PROTOTYPE(EXP)			\
     98        (EXP == 0					\
     99 	|| (!prototype_p (TREE_TYPE (EXP))	\
    100 	    && !DECL_BUILT_IN (EXP)))
    101 
    102 /* For FUNCTION_TYPE, a hidden list of types of arguments.  The same as
    103    TYPE_ARG_TYPES for functions with prototypes, but created for functions
    104    without prototypes.  */
    105 #define TYPE_ACTUAL_ARG_TYPES(NODE) TYPE_LANG_SLOT_1 (NODE)
    106 
    107 /* For a CONSTRUCTOR, whether some initializer contains a
    108    subexpression meaning it is not a constant expression.  */
    109 #define CONSTRUCTOR_NON_CONST(EXPR) TREE_LANG_FLAG_1 (CONSTRUCTOR_CHECK (EXPR))
    110 
    111 /* Record parser information about an expression that is irrelevant
    112    for code generation alongside a tree representing its value.  */
    113 struct c_expr
    114 {
    115   /* The value of the expression.  */
    116   tree value;
    117   /* Record the original unary/binary operator of an expression, which may
    118      have been changed by fold, STRING_CST for unparenthesized string
    119      constants, C_MAYBE_CONST_EXPR for __builtin_constant_p calls
    120      (even if parenthesized), for subexpressions, and for non-constant
    121      initializers, or ERROR_MARK for other expressions (including
    122      parenthesized expressions).  */
    123   enum tree_code original_code;
    124   /* If not NULL, the original type of an expression.  This will
    125      differ from the type of the value field for an enum constant.
    126      The type of an enum constant is a plain integer type, but this
    127      field will be the enum type.  */
    128   tree original_type;
    129 };
    130 
    131 /* Type alias for struct c_expr. This allows to use the structure
    132    inside the VEC types.  */
    133 typedef struct c_expr c_expr_t;
    134 
    135 /* A varray of c_expr_t.  */
    136 
    137 /* Append a new c_expr_t element to V.  */
    138 #define C_EXPR_APPEND(V, ELEM) \
    139   do { \
    140     c_expr_t __elem = (ELEM); \
    141     vec_safe_push (V, __elem); \
    142   } while (0)
    143 
    144 /* A kind of type specifier.  Note that this information is currently
    145    only used to distinguish tag definitions, tag references and typeof
    146    uses.  */
    147 enum c_typespec_kind {
    148   /* No typespec.  This appears only in struct c_declspec.  */
    149   ctsk_none,
    150   /* A reserved keyword type specifier.  */
    151   ctsk_resword,
    152   /* A reference to a tag, previously declared, such as "struct foo".
    153      This includes where the previous declaration was as a different
    154      kind of tag, in which case this is only valid if shadowing that
    155      tag in an inner scope.  */
    156   ctsk_tagref,
    157   /* A reference to a tag, not previously declared in a visible
    158      scope.  */
    159   ctsk_tagfirstref,
    160   /* A definition of a tag such as "struct foo { int a; }".  */
    161   ctsk_tagdef,
    162   /* A typedef name.  */
    163   ctsk_typedef,
    164   /* An ObjC-specific kind of type specifier.  */
    165   ctsk_objc,
    166   /* A typeof specifier.  */
    167   ctsk_typeof
    168 };
    169 
    170 /* A type specifier: this structure is created in the parser and
    171    passed to declspecs_add_type only.  */
    172 struct c_typespec {
    173   /* What kind of type specifier this is.  */
    174   enum c_typespec_kind kind;
    175   /* Whether the expression has operands suitable for use in constant
    176      expressions.  */
    177   bool expr_const_operands;
    178   /* The specifier itself.  */
    179   tree spec;
    180   /* An expression to be evaluated before the type specifier, in the
    181      case of typeof specifiers, or NULL otherwise or if no such
    182      expression is required for a particular typeof specifier.  In
    183      particular, when typeof is applied to an expression of variably
    184      modified type, that expression must be evaluated in order to
    185      determine array sizes that form part of the type, but the
    186      expression itself (as opposed to the array sizes) forms no part
    187      of the type and so needs to be recorded separately.  */
    188   tree expr;
    189 };
    190 
    191 /* A storage class specifier.  */
    192 enum c_storage_class {
    193   csc_none,
    194   csc_auto,
    195   csc_extern,
    196   csc_register,
    197   csc_static,
    198   csc_typedef
    199 };
    200 
    201 /* A type specifier keyword "void", "_Bool", "char", "int", "float",
    202    "double", "_Decimal32", "_Decimal64", "_Decimal128", "_Fract", "_Accum",
    203    or none of these.  */
    204 enum c_typespec_keyword {
    205   cts_none,
    206   cts_void,
    207   cts_bool,
    208   cts_char,
    209   cts_int,
    210   cts_float,
    211   cts_int128,
    212   cts_double,
    213   cts_dfloat32,
    214   cts_dfloat64,
    215   cts_dfloat128,
    216   cts_fract,
    217   cts_accum
    218 };
    219 
    220 /* This enum lists all the possible declarator specifiers, storage
    221    class or attribute that a user can write.  There is at least one
    222    enumerator per possible declarator specifier in the struct
    223    c_declspecs below.
    224 
    225    It is used to index the array of declspec locations in struct
    226    c_declspecs.  */
    227 enum c_declspec_word {
    228   cdw_typespec /* A catch-all for a typespec.  */,
    229   cdw_storage_class  /* A catch-all for a storage class */,
    230   cdw_attributes,
    231   cdw_typedef,
    232   cdw_explicit_signed,
    233   cdw_deprecated,
    234   cdw_default_int,
    235   cdw_long,
    236   cdw_long_long,
    237   cdw_short,
    238   cdw_signed,
    239   cdw_unsigned,
    240   cdw_complex,
    241   cdw_inline,
    242   cdw_noreturn,
    243   cdw_thread,
    244   cdw_const,
    245   cdw_volatile,
    246   cdw_restrict,
    247   cdw_saturating,
    248   cdw_alignas,
    249   cdw_address_space,
    250   cdw_number_of_elements /* This one must always be the last
    251 			    enumerator.  */
    252 };
    253 
    254 /* A sequence of declaration specifiers in C.  When a new declaration
    255    specifier is added, please update the enum c_declspec_word above
    256    accordingly.  */
    257 struct c_declspecs {
    258   source_location locations[cdw_number_of_elements];
    259   /* The type specified, if a single type specifier such as a struct,
    260      union or enum specifier, typedef name or typeof specifies the
    261      whole type, or NULL_TREE if none or a keyword such as "void" or
    262      "char" is used.  Does not include qualifiers.  */
    263   tree type;
    264   /* Any expression to be evaluated before the type, from a typeof
    265      specifier.  */
    266   tree expr;
    267   /* The attributes from a typedef decl.  */
    268   tree decl_attr;
    269   /* When parsing, the attributes.  Outside the parser, this will be
    270      NULL; attributes (possibly from multiple lists) will be passed
    271      separately.  */
    272   tree attrs;
    273   /* The base-2 log of the greatest alignment required by an _Alignas
    274      specifier, in bytes, or -1 if no such specifiers with nonzero
    275      alignment.  */
    276   int align_log;
    277   /* The storage class specifier, or csc_none if none.  */
    278   enum c_storage_class storage_class;
    279   /* Any type specifier keyword used such as "int", not reflecting
    280      modifiers such as "short", or cts_none if none.  */
    281   ENUM_BITFIELD (c_typespec_keyword) typespec_word : 8;
    282   /* The kind of type specifier if one has been seen, ctsk_none
    283      otherwise.  */
    284   ENUM_BITFIELD (c_typespec_kind) typespec_kind : 3;
    285   /* Whether any expressions in typeof specifiers may appear in
    286      constant expressions.  */
    287   BOOL_BITFIELD expr_const_operands : 1;
    288   /* Whether any declaration specifiers have been seen at all.  */
    289   BOOL_BITFIELD declspecs_seen_p : 1;
    290   /* Whether something other than a storage class specifier or
    291      attribute has been seen.  This is used to warn for the
    292      obsolescent usage of storage class specifiers other than at the
    293      start of the list.  (Doing this properly would require function
    294      specifiers to be handled separately from storage class
    295      specifiers.)  */
    296   BOOL_BITFIELD non_sc_seen_p : 1;
    297   /* Whether the type is specified by a typedef or typeof name.  */
    298   BOOL_BITFIELD typedef_p : 1;
    299   /* Whether the type is explicitly "signed" or specified by a typedef
    300      whose type is explicitly "signed".  */
    301   BOOL_BITFIELD explicit_signed_p : 1;
    302   /* Whether the specifiers include a deprecated typedef.  */
    303   BOOL_BITFIELD deprecated_p : 1;
    304   /* Whether the type defaulted to "int" because there were no type
    305      specifiers.  */
    306   BOOL_BITFIELD default_int_p : 1;
    307   /* Whether "long" was specified.  */
    308   BOOL_BITFIELD long_p : 1;
    309   /* Whether "long" was specified more than once.  */
    310   BOOL_BITFIELD long_long_p : 1;
    311   /* Whether "short" was specified.  */
    312   BOOL_BITFIELD short_p : 1;
    313   /* Whether "signed" was specified.  */
    314   BOOL_BITFIELD signed_p : 1;
    315   /* Whether "unsigned" was specified.  */
    316   BOOL_BITFIELD unsigned_p : 1;
    317   /* Whether "complex" was specified.  */
    318   BOOL_BITFIELD complex_p : 1;
    319   /* Whether "inline" was specified.  */
    320   BOOL_BITFIELD inline_p : 1;
    321   /* Whether "_Noreturn" was speciied.  */
    322   BOOL_BITFIELD noreturn_p : 1;
    323   /* Whether "__thread" was specified.  */
    324   BOOL_BITFIELD thread_p : 1;
    325   /* Whether "const" was specified.  */
    326   BOOL_BITFIELD const_p : 1;
    327   /* Whether "volatile" was specified.  */
    328   BOOL_BITFIELD volatile_p : 1;
    329   /* Whether "restrict" was specified.  */
    330   BOOL_BITFIELD restrict_p : 1;
    331   /* Whether "_Sat" was specified.  */
    332   BOOL_BITFIELD saturating_p : 1;
    333   /* Whether any alignment specifier (even with zero alignment) was
    334      specified.  */
    335   BOOL_BITFIELD alignas_p : 1;
    336   /* The address space that the declaration belongs to.  */
    337   addr_space_t address_space;
    338 };
    339 
    340 /* The various kinds of declarators in C.  */
    341 enum c_declarator_kind {
    342   /* An identifier.  */
    343   cdk_id,
    344   /* A function.  */
    345   cdk_function,
    346   /* An array.  */
    347   cdk_array,
    348   /* A pointer.  */
    349   cdk_pointer,
    350   /* Parenthesized declarator with nested attributes.  */
    351   cdk_attrs
    352 };
    353 
    354 typedef struct c_arg_tag_d {
    355   /* The argument name.  */
    356   tree id;
    357   /* The type of the argument.  */
    358   tree type;
    359 } c_arg_tag;
    360 
    361 
    362 /* Information about the parameters in a function declarator.  */
    363 struct c_arg_info {
    364   /* A list of parameter decls.  */
    365   tree parms;
    366   /* A list of structure, union and enum tags defined.  */
    367   vec<c_arg_tag, va_gc> *tags;
    368   /* A list of argument types to go in the FUNCTION_TYPE.  */
    369   tree types;
    370   /* A list of non-parameter decls (notably enumeration constants)
    371      defined with the parameters.  */
    372   tree others;
    373   /* A compound expression of VLA sizes from the parameters, or NULL.
    374      In a function definition, these are used to ensure that
    375      side-effects in sizes of arrays converted to pointers (such as a
    376      parameter int i[n++]) take place; otherwise, they are
    377      ignored.  */
    378   tree pending_sizes;
    379   /* True when these arguments had [*].  */
    380   BOOL_BITFIELD had_vla_unspec : 1;
    381 };
    382 
    383 /* A declarator.  */
    384 struct c_declarator {
    385   /* The kind of declarator.  */
    386   enum c_declarator_kind kind;
    387   location_t id_loc; /* Currently only set for cdk_id, cdk_array. */
    388   /* Except for cdk_id, the contained declarator.  For cdk_id, NULL.  */
    389   struct c_declarator *declarator;
    390   union {
    391     /* For identifiers, an IDENTIFIER_NODE or NULL_TREE if an abstract
    392        declarator.  */
    393     tree id;
    394     /* For functions.  */
    395     struct c_arg_info *arg_info;
    396     /* For arrays.  */
    397     struct {
    398       /* The array dimension, or NULL for [] and [*].  */
    399       tree dimen;
    400       /* The qualifiers inside [].  */
    401       int quals;
    402       /* The attributes (currently ignored) inside [].  */
    403       tree attrs;
    404       /* Whether [static] was used.  */
    405       BOOL_BITFIELD static_p : 1;
    406       /* Whether [*] was used.  */
    407       BOOL_BITFIELD vla_unspec_p : 1;
    408     } array;
    409     /* For pointers, the qualifiers on the pointer type.  */
    410     int pointer_quals;
    411     /* For attributes.  */
    412     tree attrs;
    413   } u;
    414 };
    415 
    416 /* A type name.  */
    417 struct c_type_name {
    418   /* The declaration specifiers.  */
    419   struct c_declspecs *specs;
    420   /* The declarator.  */
    421   struct c_declarator *declarator;
    422 };
    423 
    424 /* A parameter.  */
    425 struct c_parm {
    426   /* The declaration specifiers, minus any prefix attributes.  */
    427   struct c_declspecs *specs;
    428   /* The attributes.  */
    429   tree attrs;
    430   /* The declarator.  */
    431   struct c_declarator *declarator;
    432 };
    433 
    434 /* Used when parsing an enum.  Initialized by start_enum.  */
    435 struct c_enum_contents
    436 {
    437   /* While defining an enum type, this is 1 plus the last enumerator
    438      constant value.  */
    439   tree enum_next_value;
    440 
    441   /* Nonzero means that there was overflow computing enum_next_value.  */
    442   int enum_overflow;
    443 };
    444 
    445 /* A type of reference to a static identifier in an inline
    446    function.  */
    447 enum c_inline_static_type {
    448   /* Identifier with internal linkage used in function that may be an
    449      inline definition (i.e., file-scope static).  */
    450   csi_internal,
    451   /* Modifiable object with static storage duration defined in
    452      function that may be an inline definition (i.e., local
    453      static).  */
    454   csi_modifiable
    455 };
    456 
    457 
    458 /* in c-parser.c */
    460 extern void c_parse_init (void);
    461 
    462 /* in c-aux-info.c */
    463 extern void gen_aux_info_record (tree, int, int, int);
    464 
    465 /* in c-decl.c */
    466 struct c_spot_bindings;
    467 struct c_struct_parse_info;
    468 extern struct obstack parser_obstack;
    469 extern tree c_break_label;
    470 extern tree c_cont_label;
    471 
    472 extern bool global_bindings_p (void);
    473 extern void push_scope (void);
    474 extern tree pop_scope (void);
    475 extern void c_bindings_start_stmt_expr (struct c_spot_bindings *);
    476 extern void c_bindings_end_stmt_expr (struct c_spot_bindings *);
    477 
    478 extern void record_inline_static (location_t, tree, tree,
    479 				  enum c_inline_static_type);
    480 extern void c_init_decl_processing (void);
    481 extern void c_print_identifier (FILE *, tree, int);
    482 extern int quals_from_declspecs (const struct c_declspecs *);
    483 extern struct c_declarator *build_array_declarator (location_t, tree,
    484     						    struct c_declspecs *,
    485 						    bool, bool);
    486 extern tree build_enumerator (location_t, location_t, struct c_enum_contents *,
    487 			      tree, tree);
    488 extern tree check_for_loop_decls (location_t, bool);
    489 extern void mark_forward_parm_decls (void);
    490 extern void declare_parm_level (void);
    491 extern void undeclared_variable (location_t, tree);
    492 extern tree lookup_label_for_goto (location_t, tree);
    493 extern tree declare_label (tree);
    494 extern tree define_label (location_t, tree);
    495 extern struct c_spot_bindings *c_get_switch_bindings (void);
    496 extern void c_release_switch_bindings (struct c_spot_bindings *);
    497 extern bool c_check_switch_jump_warnings (struct c_spot_bindings *,
    498 					  location_t, location_t);
    499 extern void finish_decl (tree, location_t, tree, tree, tree);
    500 extern tree finish_enum (tree, tree, tree);
    501 extern void finish_function (void);
    502 extern tree finish_struct (location_t, tree, tree, tree,
    503 			   struct c_struct_parse_info *);
    504 extern struct c_arg_info *build_arg_info (void);
    505 extern struct c_arg_info *get_parm_info (bool, tree);
    506 extern tree grokfield (location_t, struct c_declarator *,
    507 		       struct c_declspecs *, tree, tree *);
    508 extern tree groktypename (struct c_type_name *, tree *, bool *);
    509 extern tree grokparm (const struct c_parm *, tree *);
    510 extern tree implicitly_declare (location_t, tree);
    511 extern void keep_next_level (void);
    512 extern void pending_xref_error (void);
    513 extern void c_push_function_context (void);
    514 extern void c_pop_function_context (void);
    515 extern void push_parm_decl (const struct c_parm *, tree *);
    516 extern struct c_declarator *set_array_declarator_inner (struct c_declarator *,
    517 							struct c_declarator *);
    518 extern tree c_builtin_function (tree);
    519 extern tree c_builtin_function_ext_scope (tree);
    520 extern void shadow_tag (const struct c_declspecs *);
    521 extern void shadow_tag_warned (const struct c_declspecs *, int);
    522 extern tree start_enum (location_t, struct c_enum_contents *, tree);
    523 extern int  start_function (struct c_declspecs *, struct c_declarator *, tree);
    524 extern tree start_decl (struct c_declarator *, struct c_declspecs *, bool,
    525 			tree);
    526 extern tree start_struct (location_t, enum tree_code, tree,
    527 			  struct c_struct_parse_info **);
    528 extern void store_parm_decls (void);
    529 extern void store_parm_decls_from (struct c_arg_info *);
    530 extern tree xref_tag (enum tree_code, tree);
    531 extern struct c_typespec parser_xref_tag (location_t, enum tree_code, tree);
    532 extern struct c_parm *build_c_parm (struct c_declspecs *, tree,
    533 				    struct c_declarator *);
    534 extern struct c_declarator *build_attrs_declarator (tree,
    535 						    struct c_declarator *);
    536 extern struct c_declarator *build_function_declarator (struct c_arg_info *,
    537 						       struct c_declarator *);
    538 extern struct c_declarator *build_id_declarator (tree);
    539 extern struct c_declarator *make_pointer_declarator (struct c_declspecs *,
    540 						     struct c_declarator *);
    541 extern struct c_declspecs *build_null_declspecs (void);
    542 extern struct c_declspecs *declspecs_add_qual (source_location,
    543 					       struct c_declspecs *, tree);
    544 extern struct c_declspecs *declspecs_add_type (location_t,
    545 					       struct c_declspecs *,
    546 					       struct c_typespec);
    547 extern struct c_declspecs *declspecs_add_scspec (source_location,
    548 						 struct c_declspecs *, tree);
    549 extern struct c_declspecs *declspecs_add_attrs (source_location,
    550 						struct c_declspecs *, tree);
    551 extern struct c_declspecs *declspecs_add_addrspace (source_location,
    552 						    struct c_declspecs *,
    553 						    addr_space_t);
    554 extern struct c_declspecs *declspecs_add_alignas (source_location,
    555 						  struct c_declspecs *, tree);
    556 extern struct c_declspecs *finish_declspecs (struct c_declspecs *);
    557 
    558 /* in c-objc-common.c */
    559 extern bool c_objc_common_init (void);
    560 extern bool c_missing_noreturn_ok_p (tree);
    561 extern bool c_warn_unused_global_decl (const_tree);
    562 extern void c_initialize_diagnostics (diagnostic_context *);
    563 extern bool c_vla_unspec_p (tree x, tree fn);
    564 
    565 /* in c-typeck.c */
    566 extern int in_alignof;
    567 extern int in_sizeof;
    568 extern int in_typeof;
    569 
    570 extern tree c_last_sizeof_arg;
    571 
    572 extern struct c_switch *c_switch_stack;
    573 
    574 extern tree c_objc_common_truthvalue_conversion (location_t, tree);
    575 extern tree require_complete_type (tree);
    576 extern int same_translation_unit_p (const_tree, const_tree);
    577 extern int comptypes (tree, tree);
    578 extern int comptypes_check_different_types (tree, tree, bool *);
    579 extern bool c_vla_type_p (const_tree);
    580 extern bool c_mark_addressable (tree);
    581 extern void c_incomplete_type_error (const_tree, const_tree);
    582 extern tree c_type_promotes_to (tree);
    583 extern struct c_expr default_function_array_conversion (location_t,
    584 							struct c_expr);
    585 extern struct c_expr default_function_array_read_conversion (location_t,
    586 							     struct c_expr);
    587 extern void mark_exp_read (tree);
    588 extern tree composite_type (tree, tree);
    589 extern tree build_component_ref (location_t, tree, tree);
    590 extern tree build_array_ref (location_t, tree, tree);
    591 extern tree build_external_ref (location_t, tree, int, tree *);
    592 extern void pop_maybe_used (bool);
    593 extern struct c_expr c_expr_sizeof_expr (location_t, struct c_expr);
    594 extern struct c_expr c_expr_sizeof_type (location_t, struct c_type_name *);
    595 extern struct c_expr parser_build_unary_op (location_t, enum tree_code,
    596     					    struct c_expr);
    597 extern struct c_expr parser_build_binary_op (location_t,
    598     					     enum tree_code, struct c_expr,
    599 					     struct c_expr);
    600 extern tree build_conditional_expr (location_t, tree, bool, tree, tree,
    601 				    tree, tree);
    602 extern tree build_compound_expr (location_t, tree, tree);
    603 extern tree c_cast_expr (location_t, struct c_type_name *, tree);
    604 extern tree build_c_cast (location_t, tree, tree);
    605 extern void store_init_value (location_t, tree, tree, tree);
    606 extern void error_init (const char *);
    607 extern void pedwarn_init (location_t, int opt, const char *);
    608 extern void maybe_warn_string_init (tree, struct c_expr);
    609 extern void start_init (tree, tree, int);
    610 extern void finish_init (void);
    611 extern void really_start_incremental_init (tree);
    612 extern void push_init_level (int, struct obstack *);
    613 extern struct c_expr pop_init_level (int, struct obstack *);
    614 extern void set_init_index (tree, tree, struct obstack *);
    615 extern void set_init_label (tree, struct obstack *);
    616 extern void process_init_element (struct c_expr, bool, struct obstack *);
    617 extern tree build_compound_literal (location_t, tree, tree, bool);
    618 extern void check_compound_literal_type (location_t, struct c_type_name *);
    619 extern tree c_start_case (location_t, location_t, tree);
    620 extern void c_finish_case (tree);
    621 extern tree build_asm_expr (location_t, tree, tree, tree, tree, tree, bool);
    622 extern tree build_asm_stmt (tree, tree);
    623 extern int c_types_compatible_p (tree, tree);
    624 extern tree c_begin_compound_stmt (bool);
    625 extern tree c_end_compound_stmt (location_t, tree, bool);
    626 extern void c_finish_if_stmt (location_t, tree, tree, tree, bool);
    627 extern void c_finish_loop (location_t, tree, tree, tree, tree, tree, bool);
    628 extern tree c_begin_stmt_expr (void);
    629 extern tree c_finish_stmt_expr (location_t, tree);
    630 extern tree c_process_expr_stmt (location_t, tree);
    631 extern tree c_finish_expr_stmt (location_t, tree);
    632 extern tree c_finish_return (location_t, tree, tree);
    633 extern tree c_finish_bc_stmt (location_t, tree *, bool);
    634 extern tree c_finish_goto_label (location_t, tree);
    635 extern tree c_finish_goto_ptr (location_t, tree);
    636 extern tree c_expr_to_decl (tree, bool *, bool *);
    637 extern tree c_begin_omp_parallel (void);
    638 extern tree c_finish_omp_parallel (location_t, tree, tree);
    639 extern tree c_begin_omp_task (void);
    640 extern tree c_finish_omp_task (location_t, tree, tree);
    641 extern tree c_finish_omp_clauses (tree);
    642 extern tree c_build_va_arg (location_t, tree, tree);
    643 extern tree c_finish_transaction (location_t, tree, int);
    644 extern tree c_build_function_call_vec (location_t, tree, vec<tree, va_gc> *,
    645 				       vec<tree, va_gc> *);
    646 
    647 /* Set to 0 at beginning of a function definition, set to 1 if
    648    a return statement that specifies a return value is seen.  */
    649 
    650 extern int current_function_returns_value;
    651 
    652 /* Set to 0 at beginning of a function definition, set to 1 if
    653    a return statement with no argument is seen.  */
    654 
    655 extern int current_function_returns_null;
    656 
    657 /* Set to 0 at beginning of a function definition, set to 1 if
    658    a call to a noreturn function is seen.  */
    659 
    660 extern int current_function_returns_abnormally;
    661 
    662 /* Mode used to build pointers (VOIDmode means ptr_mode).  */
    663 
    664 extern enum machine_mode c_default_pointer_mode;
    665 
    666 /* In c-decl.c */
    667 extern void c_finish_incomplete_decl (tree);
    668 extern void c_write_global_declarations (void);
    669 
    670 /* In c-errors.c */
    671 extern void pedwarn_c90 (location_t, int opt, const char *, ...) ATTRIBUTE_GCC_DIAG(3,4);
    672 extern void pedwarn_c99 (location_t, int opt, const char *, ...) ATTRIBUTE_GCC_DIAG(3,4);
    673 
    674 #endif /* ! GCC_C_TREE_H */
    675