/* Definitions for C parsing and type checking.
   Copyright (C) 1987-2017 Free Software Foundation, Inc.

This file is part of GCC.

GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 3, or (at your option) any later
version.

GCC is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
for more details.

You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3.  If not see
<http://www.gnu.org/licenses/>.  */

#ifndef GCC_C_TREE_H
#define GCC_C_TREE_H

#include "c-family/c-common.h"
#include "diagnostic.h"

/* struct lang_identifier is private to c-decl.c, but langhooks.c needs to
   know how big it is.  This is sanity-checked in c-decl.c.  */
#define C_SIZEOF_STRUCT_LANG_IDENTIFIER \
  (sizeof (struct c_common_identifier) + 3 * sizeof (void *))

/* In a RECORD_TYPE or UNION_TYPE, nonzero if any component is read-only.  */
#define C_TYPE_FIELDS_READONLY(TYPE) TREE_LANG_FLAG_1 (TYPE)

/* In a RECORD_TYPE or UNION_TYPE, nonzero if any component is volatile.  */
#define C_TYPE_FIELDS_VOLATILE(TYPE) TREE_LANG_FLAG_2 (TYPE)

/* In a RECORD_TYPE or UNION_TYPE or ENUMERAL_TYPE
   nonzero if the definition of the type has already started.  */
#define C_TYPE_BEING_DEFINED(TYPE) TYPE_LANG_FLAG_0 (TYPE)

/* In an incomplete RECORD_TYPE or UNION_TYPE, a list of variable
   declarations whose type would be completed by completing that type.  */
#define C_TYPE_INCOMPLETE_VARS(TYPE) TYPE_VFIELD (TYPE)

/* In an IDENTIFIER_NODE, nonzero if this identifier is actually a
   keyword.  C_RID_CODE (node) is then the RID_* value of the keyword.  */
#define C_IS_RESERVED_WORD(ID) TREE_LANG_FLAG_0 (ID)

/* Record whether a type or decl was written with nonconstant size.
   Note that TYPE_SIZE may have simplified to a constant.  */
#define C_TYPE_VARIABLE_SIZE(TYPE) TYPE_LANG_FLAG_1 (TYPE)
#define C_DECL_VARIABLE_SIZE(TYPE) DECL_LANG_FLAG_0 (TYPE)

/* Record whether a type is defined inside a struct or union type.
   This is used for -Wc++-compat. */
#define C_TYPE_DEFINED_IN_STRUCT(TYPE) TYPE_LANG_FLAG_2 (TYPE)

/* Record whether an "incomplete type" error was given for the type.  */
#define C_TYPE_ERROR_REPORTED(TYPE) TYPE_LANG_FLAG_3 (TYPE)

/* Record whether a typedef for type `int' was actually `signed int'.  */
#define C_TYPEDEF_EXPLICITLY_SIGNED(EXP) DECL_LANG_FLAG_1 (EXP)

/* For a FUNCTION_DECL, nonzero if it was defined without an explicit
   return type.  */
#define C_FUNCTION_IMPLICIT_INT(EXP) DECL_LANG_FLAG_1 (EXP)

/* For a FUNCTION_DECL, nonzero if it was an implicit declaration.  */
#define C_DECL_IMPLICIT(EXP) DECL_LANG_FLAG_2 (EXP)

/* For a PARM_DECL, nonzero if it was declared as an array.  */
#define C_ARRAY_PARAMETER(NODE) DECL_LANG_FLAG_0 (NODE)

/* For FUNCTION_DECLs, evaluates true if the decl is built-in but has
   been declared.  */
#define C_DECL_DECLARED_BUILTIN(EXP)		\
  DECL_LANG_FLAG_3 (FUNCTION_DECL_CHECK (EXP))

/* For FUNCTION_DECLs, evaluates true if the decl is built-in, has a
   built-in prototype and does not have a non-built-in prototype.  */
#define C_DECL_BUILTIN_PROTOTYPE(EXP)		\
  DECL_LANG_FLAG_6 (FUNCTION_DECL_CHECK (EXP))

/* Record whether a decl was declared register.  This is strictly a
   front-end flag, whereas DECL_REGISTER is used for code generation;
   they may differ for structures with volatile fields.  */
#define C_DECL_REGISTER(EXP) DECL_LANG_FLAG_4 (EXP)

/* Record whether a decl was used in an expression anywhere except an
   unevaluated operand of sizeof / typeof / alignof.  This is only
   used for functions declared static but not defined, though outside
   sizeof and typeof it is set for other function decls as well.  */
#define C_DECL_USED(EXP) DECL_LANG_FLAG_5 (FUNCTION_DECL_CHECK (EXP))

/* Record whether a variable has been declared threadprivate by
   #pragma omp threadprivate.  */
#define C_DECL_THREADPRIVATE_P(DECL) DECL_LANG_FLAG_3 (VAR_DECL_CHECK (DECL))

/* Nonzero for a decl which either doesn't exist or isn't a prototype.
   N.B. Could be simplified if all built-in decls had complete prototypes
   (but this is presently difficult because some of them need FILE*).  */
#define C_DECL_ISNT_PROTOTYPE(EXP)			\
       (EXP == 0					\
	|| (!prototype_p (TREE_TYPE (EXP))	\
	    && !DECL_BUILT_IN (EXP)))

/* For FUNCTION_TYPE, a hidden list of types of arguments.  The same as
   TYPE_ARG_TYPES for functions with prototypes, but created for functions
   without prototypes.  */
#define TYPE_ACTUAL_ARG_TYPES(NODE) TYPE_LANG_SLOT_1 (NODE)

/* For a CONSTRUCTOR, whether some initializer contains a
   subexpression meaning it is not a constant expression.  */
#define CONSTRUCTOR_NON_CONST(EXPR) TREE_LANG_FLAG_1 (CONSTRUCTOR_CHECK (EXPR))

/* Record parser information about an expression that is irrelevant
   for code generation alongside a tree representing its value.  */
struct c_expr
{
  /* The value of the expression.  */
  tree value;
  /* Record the original unary/binary operator of an expression, which may
     have been changed by fold, STRING_CST for unparenthesized string
     constants, C_MAYBE_CONST_EXPR for __builtin_constant_p calls
     (even if parenthesized), for subexpressions, and for non-constant
     initializers, or ERROR_MARK for other expressions (including
     parenthesized expressions).  */
  enum tree_code original_code;
  /* If not NULL, the original type of an expression.  This will
     differ from the type of the value field for an enum constant.
     The type of an enum constant is a plain integer type, but this
     field will be the enum type.  */
  tree original_type;

  /* The source range of this expression.  This is redundant
     for node values that have locations, but not all node kinds
     have locations (e.g. constants, and references to params, locals,
     etc), so we stash a copy here.  */
  source_range src_range;

  /* Access to the first and last locations within the source spelling
     of this expression.  */
  location_t get_start () const { return src_range.m_start; }
  location_t get_finish () const { return src_range.m_finish; }

  /* Set the value to error_mark_node whilst ensuring that src_range
     is initialized.  */
  void set_error ()
  {
    value = error_mark_node;
    src_range.m_start = UNKNOWN_LOCATION;
    src_range.m_finish = UNKNOWN_LOCATION;
  }
};

/* Type alias for struct c_expr. This allows to use the structure
   inside the VEC types.  */
typedef struct c_expr c_expr_t;

/* A kind of type specifier.  Note that this information is currently
   only used to distinguish tag definitions, tag references and typeof
   uses.  */
enum c_typespec_kind {
  /* No typespec.  This appears only in struct c_declspec.  */
  ctsk_none,
  /* A reserved keyword type specifier.  */
  ctsk_resword,
  /* A reference to a tag, previously declared, such as "struct foo".
     This includes where the previous declaration was as a different
     kind of tag, in which case this is only valid if shadowing that
     tag in an inner scope.  */
  ctsk_tagref,
  /* A reference to a tag, not previously declared in a visible
     scope.  */
  ctsk_tagfirstref,
  /* A definition of a tag such as "struct foo { int a; }".  */
  ctsk_tagdef,
  /* A typedef name.  */
  ctsk_typedef,
  /* An ObjC-specific kind of type specifier.  */
  ctsk_objc,
  /* A typeof specifier, or _Atomic ( type-name ).  */
  ctsk_typeof
};

/* A type specifier: this structure is created in the parser and
   passed to declspecs_add_type only.  */
struct c_typespec {
  /* What kind of type specifier this is.  */
  enum c_typespec_kind kind;
  /* Whether the expression has operands suitable for use in constant
     expressions.  */
  bool expr_const_operands;
  /* The specifier itself.  */
  tree spec;
  /* An expression to be evaluated before the type specifier, in the
     case of typeof specifiers, or NULL otherwise or if no such
     expression is required for a particular typeof specifier.  In
     particular, when typeof is applied to an expression of variably
     modified type, that expression must be evaluated in order to
     determine array sizes that form part of the type, but the
     expression itself (as opposed to the array sizes) forms no part
     of the type and so needs to be recorded separately.  */
  tree expr;
};

/* A storage class specifier.  */
enum c_storage_class {
  csc_none,
  csc_auto,
  csc_extern,
  csc_register,
  csc_static,
  csc_typedef
};

/* A type specifier keyword "void", "_Bool", "char", "int", "float",
   "double", "_Decimal32", "_Decimal64", "_Decimal128", "_Fract", "_Accum",
   or none of these.  */
enum c_typespec_keyword {
  cts_none,
  cts_void,
  cts_bool,
  cts_char,
  cts_int,
  cts_float,
  cts_int_n,
  cts_double,
  cts_dfloat32,
  cts_dfloat64,
  cts_dfloat128,
  cts_floatn_nx,
  cts_fract,
  cts_accum,
  cts_auto_type
};

/* This enum lists all the possible declarator specifiers, storage
   class or attribute that a user can write.  There is at least one
   enumerator per possible declarator specifier in the struct
   c_declspecs below.

   It is used to index the array of declspec locations in struct
   c_declspecs.  */
enum c_declspec_word {
  cdw_typespec /* A catch-all for a typespec.  */,
  cdw_storage_class  /* A catch-all for a storage class */,
  cdw_attributes,
  cdw_typedef,
  cdw_explicit_signed,
  cdw_deprecated,
  cdw_default_int,
  cdw_long,
  cdw_long_long,
  cdw_short,
  cdw_signed,
  cdw_unsigned,
  cdw_complex,
  cdw_inline,
  cdw_noreturn,
  cdw_thread,
  cdw_const,
  cdw_volatile,
  cdw_restrict,
  cdw_atomic,
  cdw_saturating,
  cdw_alignas,
  cdw_address_space,
  cdw_gimple,
  cdw_rtl,
  cdw_number_of_elements /* This one must always be the last
			    enumerator.  */
};

/* A sequence of declaration specifiers in C.  When a new declaration
   specifier is added, please update the enum c_declspec_word above
   accordingly.  */
struct c_declspecs {
  source_location locations[cdw_number_of_elements];
  /* The type specified, if a single type specifier such as a struct,
     union or enum specifier, typedef name or typeof specifies the
     whole type, or NULL_TREE if none or a keyword such as "void" or
     "char" is used.  Does not include qualifiers.  */
  tree type;
  /* Any expression to be evaluated before the type, from a typeof
     specifier.  */
  tree expr;
  /* The attributes from a typedef decl.  */
  tree decl_attr;
  /* When parsing, the attributes.  Outside the parser, this will be
     NULL; attributes (possibly from multiple lists) will be passed
     separately.  */
  tree attrs;
  /* The pass to start compiling a __GIMPLE or __RTL function with.  */
  char *gimple_or_rtl_pass;
  /* The base-2 log of the greatest alignment required by an _Alignas
     specifier, in bytes, or -1 if no such specifiers with nonzero
     alignment.  */
  int align_log;
  /* For the __intN declspec, this stores the index into the int_n_* arrays.  */
  int int_n_idx;
  /* For the _FloatN and _FloatNx declspec, this stores the index into
     the floatn_nx_types array.  */
  int floatn_nx_idx;
  /* The storage class specifier, or csc_none if none.  */
  enum c_storage_class storage_class;
  /* Any type specifier keyword used such as "int", not reflecting
     modifiers such as "short", or cts_none if none.  */
  ENUM_BITFIELD (c_typespec_keyword) typespec_word : 8;
  /* The kind of type specifier if one has been seen, ctsk_none
     otherwise.  */
  ENUM_BITFIELD (c_typespec_kind) typespec_kind : 3;
  /* Whether any expressions in typeof specifiers may appear in
     constant expressions.  */
  BOOL_BITFIELD expr_const_operands : 1;
  /* Whether any declaration specifiers have been seen at all.  */
  BOOL_BITFIELD declspecs_seen_p : 1;
  /* Whether something other than a storage class specifier or
     attribute has been seen.  This is used to warn for the
     obsolescent usage of storage class specifiers other than at the
     start of the list.  (Doing this properly would require function
     specifiers to be handled separately from storage class
     specifiers.)  */
  BOOL_BITFIELD non_sc_seen_p : 1;
  /* Whether the type is specified by a typedef or typeof name.  */
  BOOL_BITFIELD typedef_p : 1;
  /* Whether the type is explicitly "signed" or specified by a typedef
     whose type is explicitly "signed".  */
  BOOL_BITFIELD explicit_signed_p : 1;
  /* Whether the specifiers include a deprecated typedef.  */
  BOOL_BITFIELD deprecated_p : 1;
  /* Whether the type defaulted to "int" because there were no type
     specifiers.  */
  BOOL_BITFIELD default_int_p : 1;
  /* Whether "long" was specified.  */
  BOOL_BITFIELD long_p : 1;
  /* Whether "long" was specified more than once.  */
  BOOL_BITFIELD long_long_p : 1;
  /* Whether "short" was specified.  */
  BOOL_BITFIELD short_p : 1;
  /* Whether "signed" was specified.  */
  BOOL_BITFIELD signed_p : 1;
  /* Whether "unsigned" was specified.  */
  BOOL_BITFIELD unsigned_p : 1;
  /* Whether "complex" was specified.  */
  BOOL_BITFIELD complex_p : 1;
  /* Whether "inline" was specified.  */
  BOOL_BITFIELD inline_p : 1;
  /* Whether "_Noreturn" was speciied.  */
  BOOL_BITFIELD noreturn_p : 1;
  /* Whether "__thread" or "_Thread_local" was specified.  */
  BOOL_BITFIELD thread_p : 1;
  /* Whether "__thread" rather than "_Thread_local" was specified.  */
  BOOL_BITFIELD thread_gnu_p : 1;
  /* Whether "const" was specified.  */
  BOOL_BITFIELD const_p : 1;
  /* Whether "volatile" was specified.  */
  BOOL_BITFIELD volatile_p : 1;
  /* Whether "restrict" was specified.  */
  BOOL_BITFIELD restrict_p : 1;
  /* Whether "_Atomic" was specified.  */
  BOOL_BITFIELD atomic_p : 1;
  /* Whether "_Sat" was specified.  */
  BOOL_BITFIELD saturating_p : 1;
  /* Whether any alignment specifier (even with zero alignment) was
     specified.  */
  BOOL_BITFIELD alignas_p : 1;
  /* Whether any __GIMPLE specifier was specified.  */
  BOOL_BITFIELD gimple_p : 1;
  /* Whether any __RTL specifier was specified.  */
  BOOL_BITFIELD rtl_p : 1;
  /* The address space that the declaration belongs to.  */
  addr_space_t address_space;
};

/* The various kinds of declarators in C.  */
enum c_declarator_kind {
  /* An identifier.  */
  cdk_id,
  /* A function.  */
  cdk_function,
  /* An array.  */
  cdk_array,
  /* A pointer.  */
  cdk_pointer,
  /* Parenthesized declarator with nested attributes.  */
  cdk_attrs
};

struct c_arg_tag {
  /* The argument name.  */
  tree id;
  /* The type of the argument.  */
  tree type;
};


/* Information about the parameters in a function declarator.  */
struct c_arg_info {
  /* A list of parameter decls.  */
  tree parms;
  /* A list of structure, union and enum tags defined.  */
  vec<c_arg_tag, va_gc> *tags;
  /* A list of argument types to go in the FUNCTION_TYPE.  */
  tree types;
  /* A list of non-parameter decls (notably enumeration constants)
     defined with the parameters.  */
  tree others;
  /* A compound expression of VLA sizes from the parameters, or NULL.
     In a function definition, these are used to ensure that
     side-effects in sizes of arrays converted to pointers (such as a
     parameter int i[n++]) take place; otherwise, they are
     ignored.  */
  tree pending_sizes;
  /* True when these arguments had [*].  */
  BOOL_BITFIELD had_vla_unspec : 1;
};

/* A declarator.  */
struct c_declarator {
  /* The kind of declarator.  */
  enum c_declarator_kind kind;
  location_t id_loc; /* Currently only set for cdk_id, cdk_array. */
  /* Except for cdk_id, the contained declarator.  For cdk_id, NULL.  */
  struct c_declarator *declarator;
  union {
    /* For identifiers, an IDENTIFIER_NODE or NULL_TREE if an abstract
       declarator.  */
    tree id;
    /* For functions.  */
    struct c_arg_info *arg_info;
    /* For arrays.  */
    struct {
      /* The array dimension, or NULL for [] and [*].  */
      tree dimen;
      /* The qualifiers inside [].  */
      int quals;
      /* The attributes (currently ignored) inside [].  */
      tree attrs;
      /* Whether [static] was used.  */
      BOOL_BITFIELD static_p : 1;
      /* Whether [*] was used.  */
      BOOL_BITFIELD vla_unspec_p : 1;
    } array;
    /* For pointers, the qualifiers on the pointer type.  */
    int pointer_quals;
    /* For attributes.  */
    tree attrs;
  } u;
};

/* A type name.  */
struct c_type_name {
  /* The declaration specifiers.  */
  struct c_declspecs *specs;
  /* The declarator.  */
  struct c_declarator *declarator;
};

/* A parameter.  */
struct c_parm {
  /* The declaration specifiers, minus any prefix attributes.  */
  struct c_declspecs *specs;
  /* The attributes.  */
  tree attrs;
  /* The declarator.  */
  struct c_declarator *declarator;
};

/* Used when parsing an enum.  Initialized by start_enum.  */
struct c_enum_contents
{
  /* While defining an enum type, this is 1 plus the last enumerator
     constant value.  */
  tree enum_next_value;

  /* Nonzero means that there was overflow computing enum_next_value.  */
  int enum_overflow;
};

/* A type of reference to a static identifier in an inline
   function.  */
enum c_inline_static_type {
  /* Identifier with internal linkage used in function that may be an
     inline definition (i.e., file-scope static).  */
  csi_internal,
  /* Modifiable object with static storage duration defined in
     function that may be an inline definition (i.e., local
     static).  */
  csi_modifiable
};