Comment fixes.

[pf3gnuchains/gcc-fork.git] / gcc / tree.h

/* Front-end tree definitions for GNU compiler.
   Copyright (C) 1989 Free Software Foundation, Inc.

This file is part of GNU CC.

GNU CC 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 2, or (at your option)
any later version.

GNU CC 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 GNU CC; see the file COPYING.  If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.  */

#include "machmode.h"

/* codes of tree nodes */

#define DEFTREECODE(SYM, STRING, TYPE, NARGS)   SYM,

enum tree_code {
#include "tree.def"

  LAST_AND_UNUSED_TREE_CODE     /* A convenient way to get a value for
                                   NUM_TREE_CODE.  */
};

#undef DEFTREECODE

/* Number of tree codes.  */
#define NUM_TREE_CODES ((int)LAST_AND_UNUSED_TREE_CODE)

/* Indexed by enum tree_code, contains a character which is
   `<' for a comparison expression, `1', for a unary arithmetic
   expression, `2' for a binary arithmetic expression, `e' for
   other types of expressions, `r' for a reference, `c' for a
   constant, `d' for a decl, `t' for a type, `s' for a statement,
   and `x' for anything else (TREE_LIST, IDENTIFIER, etc).  */

extern char **tree_code_type;
#define TREE_CODE_CLASS(CODE)   (*tree_code_type[(int) (CODE)])

/* Number of argument-words in each kind of tree-node.  */

extern int *tree_code_length;

/* Names of tree components.  */

extern char **tree_code_name;
\f
/* Codes that identify the various built in functions
   so that expand_call can identify them quickly.  */

enum built_in_function
{
  NOT_BUILT_IN,
  BUILT_IN_ALLOCA,
  BUILT_IN_ABS,
  BUILT_IN_FABS,
  BUILT_IN_LABS,
  BUILT_IN_FFS,
  BUILT_IN_DIV,
  BUILT_IN_LDIV,
  BUILT_IN_FFLOOR,
  BUILT_IN_FCEIL,
  BUILT_IN_FMOD,
  BUILT_IN_FREM,
  BUILT_IN_MEMCPY,
  BUILT_IN_MEMCMP,
  BUILT_IN_MEMSET,
  BUILT_IN_STRCPY,
  BUILT_IN_STRCMP,
  BUILT_IN_STRLEN,
  BUILT_IN_FSQRT,
  BUILT_IN_SIN,
  BUILT_IN_COS,
  BUILT_IN_GETEXP,
  BUILT_IN_GETMAN,
  BUILT_IN_SAVEREGS,
  BUILT_IN_CLASSIFY_TYPE,
  BUILT_IN_NEXT_ARG,
  BUILT_IN_ARGS_INFO,
  BUILT_IN_CONSTANT_P,
  BUILT_IN_FRAME_ADDRESS,
  BUILT_IN_RETURN_ADDRESS,
  BUILT_IN_CALLER_RETURN_ADDRESS,

  /* C++ extensions */
  BUILT_IN_NEW,
  BUILT_IN_VEC_NEW,
  BUILT_IN_DELETE,
  BUILT_IN_VEC_DELETE
};
\f
/* The definition of tree nodes fills the next several pages.  */

/* A tree node can represent a data type, a variable, an expression
   or a statement.  Each node has a TREE_CODE which says what kind of
   thing it represents.  Some common codes are:
   INTEGER_TYPE -- represents a type of integers.
   ARRAY_TYPE -- represents a type of pointer.
   VAR_DECL -- represents a declared variable.
   INTEGER_CST -- represents a constant integer value.
   PLUS_EXPR -- represents a sum (an expression).

   As for the contents of a tree node: there are some fields
   that all nodes share.  Each TREE_CODE has various special-purpose
   fields as well.  The fields of a node are never accessed directly,
   always through accessor macros.  */

/* This type is used everywhere to refer to a tree node.  */

typedef union tree_node *tree;

/* Every kind of tree node starts with this structure,
   so all nodes have these fields.

   See the accessor macros, defined below, for documentation of the fields.  */

struct tree_common
{
  union tree_node *chain;
  union tree_node *type;
#ifdef ONLY_INT_FIELDS
  unsigned int code : 8;
#else
  enum tree_code code : 8;
#endif

  unsigned side_effects_flag : 1;
  unsigned constant_flag : 1;
  unsigned permanent_flag : 1;
  unsigned addressable_flag : 1;
  unsigned volatile_flag : 1;
  unsigned readonly_flag : 1;
  unsigned unsigned_flag : 1;
  unsigned asm_written_flag: 1;

  unsigned used_flag : 1;
  unsigned raises_flag : 1;
  unsigned static_flag : 1;
  unsigned public_flag : 1;
  unsigned private_flag : 1;
  unsigned protected_flag : 1;

  unsigned lang_flag_0 : 1;
  unsigned lang_flag_1 : 1;
  unsigned lang_flag_2 : 1;
  unsigned lang_flag_3 : 1;
  unsigned lang_flag_4 : 1;
  unsigned lang_flag_5 : 1;
  unsigned lang_flag_6 : 1;
  /* There is room for two more flags.  */
};

/* Define accessors for the fields that all tree nodes have
   (though some fields are not used for all kinds of nodes).  */

/* The tree-code says what kind of node it is.
   Codes are defined in tree.def.  */
#define TREE_CODE(NODE) ((enum tree_code) (NODE)->common.code)
#define TREE_SET_CODE(NODE, VALUE) ((NODE)->common.code = (int) (VALUE))

/* In all nodes that are expressions, this is the data type of the expression.
   In POINTER_TYPE nodes, this is the type that the pointer points to.
   In ARRAY_TYPE nodes, this is the type of the elements.  */
#define TREE_TYPE(NODE) ((NODE)->common.type)

/* Nodes are chained together for many purposes.
   Types are chained together to record them for being output to the debugger
   (see the function `chain_type').
   Decls in the same scope are chained together to record the contents
   of the scope.
   Statement nodes for successive statements used to be chained together.
   Often lists of things are represented by TREE_LIST nodes that
   are chained together.  */

#define TREE_CHAIN(NODE) ((NODE)->common.chain)

/* Given an expression as a tree, strip any NON_LVALUE_EXPRs and NOP_EXPRs
   that don't change the machine mode.  */

#define STRIP_NOPS(EXP) \
  while ((TREE_CODE (EXP) == NOP_EXPR                           \
          || TREE_CODE (EXP) == CONVERT_EXPR                    \
          || TREE_CODE (EXP) == NON_LVALUE_EXPR)                \
         && (TYPE_MODE (TREE_TYPE (EXP))                        \
             == TYPE_MODE (TREE_TYPE (TREE_OPERAND (EXP, 0))))) \
    (EXP) = TREE_OPERAND (EXP, 0);

/* Like STRIP_NOPS, but don't alter the TREE_TYPE either.  */

#define STRIP_TYPE_NOPS(EXP) \
  while ((TREE_CODE (EXP) == NOP_EXPR                           \
          || TREE_CODE (EXP) == CONVERT_EXPR                    \
          || TREE_CODE (EXP) == NON_LVALUE_EXPR)                \
         && (TREE_TYPE (EXP)                                    \
             == TREE_TYPE (TREE_OPERAND (EXP, 0))))             \
    (EXP) = TREE_OPERAND (EXP, 0);
\f
/* Define many boolean fields that all tree nodes have.  */

/* In VAR_DECL nodes, nonzero means address of this is needed.
   So it cannot be in a register.
   In a FUNCTION_DECL, nonzero means its address is needed.
   So it must be compiled even if it is an inline function.
   In CONSTRUCTOR nodes, it means object constructed must be in memory.
   In LABEL_DECL nodes, it means a goto for this label has been seen 
   from a place outside all binding contours that restore stack levels.
   In ..._TYPE nodes, it means that objects of this type must
   be fully addressable.  This means that pieces of this
   object cannot go into register parameters, for example.
   In IDENTIFIER_NODEs, this means that some extern decl for this name
   had its address taken.  That matters for inline functions.  */
#define TREE_ADDRESSABLE(NODE) ((NODE)->common.addressable_flag)

/* In a VAR_DECL, nonzero means allocate static storage.
   In a FUNCTION_DECL, nonzero if function has been defined.
   In a CONSTRUCTOR, nonzero means allocate static storage.  */
#define TREE_STATIC(NODE) ((NODE)->common.static_flag)

/* In a CONVERT_EXPR or NOP_EXPR, this means the node was made
   implicitly and should not lead to an "unused value" warning.  */
#define TREE_NO_UNUSED_WARNING(NODE) ((NODE)->common.static_flag)

/* In a NON_LVALUE_EXPR, this means there was overflow in folding.
   The folded constant is inside the NON_LVALUE_EXPR.  */
#define TREE_CONSTANT_OVERFLOW(NODE) ((NODE)->common.static_flag)

/* Nonzero for a TREE_LIST or TREE_VEC node means that the derivation
   chain is via a `virtual' declaration.  */
#define TREE_VIA_VIRTUAL(NODE) ((NODE)->common.static_flag)

/* In a VAR_DECL or FUNCTION_DECL,
   nonzero means name is to be accessible from outside this module.
   In an identifier node, nonzero means an external declaration
   accessible from outside this module was previously seen
   for this name in an inner scope.  */
#define TREE_PUBLIC(NODE) ((NODE)->common.public_flag)

/* Nonzero for TREE_LIST or TREE_VEC node means that the path to the
   base class is via a `public' declaration, which preserves public
   fields from the base class as public.  */
#define TREE_VIA_PUBLIC(NODE) ((NODE)->common.public_flag)

/* Ditto, for `private' declarations.  */
#define TREE_VIA_PRIVATE(NODE) ((NODE)->common.private_flag)

/* Nonzero for TREE_LIST node means that the path to the
   base class is via a `protected' declaration, which preserves
   protected fields from the base class as protected.
   OVERLOADED.  */
#define TREE_VIA_PROTECTED(NODE) ((NODE)->common.static_flag)

/* In any expression, nonzero means it has side effects or reevaluation
   of the whole expression could produce a different value.
   This is set if any subexpression is a function call, a side effect
   or a reference to a volatile variable.
   In a ..._DECL, this is set only if the declaration said `volatile'.  */
#define TREE_SIDE_EFFECTS(NODE) ((NODE)->common.side_effects_flag)

/* Nonzero means this expression is volatile in the C sense:
   its address should be of type `volatile WHATEVER *'.
   In other words, the declared item is volatile qualified.
   This is used in _DECL nodes and _REF nodes.

   In a ..._TYPE node, means this type is volatile-qualified.
   But use TYPE_VOLATILE instead of this macro when the node is a type,
   because eventually we may make that a different bit.

   If this bit is set in an expression, so is TREE_SIDE_EFFECTS.  */
#define TREE_THIS_VOLATILE(NODE) ((NODE)->common.volatile_flag)

/* In a VAR_DECL, PARM_DECL or FIELD_DECL, or any kind of ..._REF node,
   nonzero means it may not be the lhs of an assignment.
   In a ..._TYPE node, means this type is const-qualified
   (but the macro TYPE_READONLY should be used instead of this macro
   when the node is a type).  */
#define TREE_READONLY(NODE) ((NODE)->common.readonly_flag)

/* Value of expression is constant.
   Always appears in all ..._CST nodes.
   May also appear in an arithmetic expression, an ADDR_EXPR or a CONSTRUCTOR
   if the value is constant.  */
#define TREE_CONSTANT(NODE) ((NODE)->common.constant_flag)

/* Nonzero means permanent node;
   node will continue to exist for the entire compiler run.
   Otherwise it will be recycled at the end of the function.  */
#define TREE_PERMANENT(NODE) ((NODE)->common.permanent_flag)

/* In INTEGER_TYPE or ENUMERAL_TYPE nodes, means an unsigned type.
   In FIELD_DECL nodes, means an unsigned bit field.
   The same bit is used in functions as DECL_BUILT_IN_NONANSI.  */
#define TREE_UNSIGNED(NODE) ((NODE)->common.unsigned_flag)

/* Nonzero in a VAR_DECL means assembler code has been written.
   Nonzero in a FUNCTION_DECL means that the function has been compiled.
   This is interesting in an inline function, since it might not need
   to be compiled separately.
   Nonzero in a RECORD_TYPE, UNION_TYPE or ENUMERAL_TYPE
   if the sdb debugging info for the type has been written.
   In a BLOCK node, nonzero if reorder_blocks has already seen this block.  */
#define TREE_ASM_WRITTEN(NODE) ((NODE)->common.asm_written_flag)

/* Nonzero in a _DECL if the name is used in its scope.
   Nonzero in an expr node means inhibit warning if value is unused.
   In IDENTIFIER_NODEs, this means that some extern decl for this name
   was used.  */
#define TREE_USED(NODE) ((NODE)->common.used_flag)

/* Nonzero for a tree node whose evaluation could result
   in the raising of an exception.  Not implemented yet.  */
#define TREE_RAISES(NODE) ((NODE)->common.raises_flag)

/* Used in classes in C++.  */
#define TREE_PRIVATE(NODE) ((NODE)->common.private_flag)
/* Used in classes in C++.
   In a BLOCK node, this is BLOCK_HANDLER_BLOCK.  */
#define TREE_PROTECTED(NODE) ((NODE)->common.protected_flag)

/* These flags are available for each language front end to use internally.  */
#define TREE_LANG_FLAG_0(NODE) ((NODE)->common.lang_flag_0)
#define TREE_LANG_FLAG_1(NODE) ((NODE)->common.lang_flag_1)
#define TREE_LANG_FLAG_2(NODE) ((NODE)->common.lang_flag_2)
#define TREE_LANG_FLAG_3(NODE) ((NODE)->common.lang_flag_3)
#define TREE_LANG_FLAG_4(NODE) ((NODE)->common.lang_flag_4)
#define TREE_LANG_FLAG_5(NODE) ((NODE)->common.lang_flag_5)
#define TREE_LANG_FLAG_6(NODE) ((NODE)->common.lang_flag_6)
\f
/* Define additional fields and accessors for nodes representing constants.  */

/* In an INTEGER_CST node.  These two together make a 2-word integer.
   If the data type is signed, the value is sign-extended to 2 words
   even though not all of them may really be in use.
   In an unsigned constant shorter than 2 words, the extra bits are 0.  */
#define TREE_INT_CST_LOW(NODE) ((NODE)->int_cst.int_cst_low)
#define TREE_INT_CST_HIGH(NODE) ((NODE)->int_cst.int_cst_high)

#define INT_CST_LT(A, B)  \
(TREE_INT_CST_HIGH (A) < TREE_INT_CST_HIGH (B)                  \
 || (TREE_INT_CST_HIGH (A) == TREE_INT_CST_HIGH (B)             \
     && ((unsigned HOST_WIDE_INT) TREE_INT_CST_LOW (A)          \
         < (unsigned HOST_WIDE_INT) TREE_INT_CST_LOW (B))))

#define INT_CST_LT_UNSIGNED(A, B)  \
(((unsigned HOST_WIDE_INT) TREE_INT_CST_HIGH (A)        \
  < (unsigned HOST_WIDE_INT) TREE_INT_CST_HIGH (B))     \
 || (((unsigned HOST_WIDE_INT) TREE_INT_CST_HIGH (A)    \
      == (unsigned HOST_WIDE_INT ) TREE_INT_CST_HIGH (B)) \
     && (((unsigned HOST_WIDE_INT) TREE_INT_CST_LOW (A) \
          < (unsigned HOST_WIDE_INT) TREE_INT_CST_LOW (B)))))

struct tree_int_cst
{
  char common[sizeof (struct tree_common)];
  HOST_WIDE_INT int_cst_low;
  HOST_WIDE_INT int_cst_high;
};

/* In REAL_CST, STRING_CST, COMPLEX_CST nodes, and CONSTRUCTOR nodes,
   and generally in all kinds of constants that could
   be given labels (rather than being immediate).  */

#define TREE_CST_RTL(NODE) ((NODE)->real_cst.rtl)

/* In a REAL_CST node.  */
/* We can represent a real value as either a `double' or a string.
   Strings don't allow for any optimization, but they do allow
   for cross-compilation.  */

#define TREE_REAL_CST(NODE) ((NODE)->real_cst.real_cst)

#include "real.h"

struct tree_real_cst
{
  char common[sizeof (struct tree_common)];
  struct rtx_def *rtl;  /* acts as link to register transfer language
                                   (rtl) info */
  REAL_VALUE_TYPE real_cst;
};

/* In a STRING_CST */
#define TREE_STRING_LENGTH(NODE) ((NODE)->string.length)
#define TREE_STRING_POINTER(NODE) ((NODE)->string.pointer)

struct tree_string
{
  char common[sizeof (struct tree_common)];
  struct rtx_def *rtl;  /* acts as link to register transfer language
                                   (rtl) info */
  int length;
  char *pointer;
};

/* In a COMPLEX_CST node.  */
#define TREE_REALPART(NODE) ((NODE)->complex.real)
#define TREE_IMAGPART(NODE) ((NODE)->complex.imag)

struct tree_complex
{
  char common[sizeof (struct tree_common)];
  struct rtx_def *rtl;  /* acts as link to register transfer language
                                   (rtl) info */
  union tree_node *real;
  union tree_node *imag;
};
\f
/* Define fields and accessors for some special-purpose tree nodes.  */

#define IDENTIFIER_LENGTH(NODE) ((NODE)->identifier.length)
#define IDENTIFIER_POINTER(NODE) ((NODE)->identifier.pointer)

struct tree_identifier
{
  char common[sizeof (struct tree_common)];
  int length;
  char *pointer;
};

/* In a TREE_LIST node.  */
#define TREE_PURPOSE(NODE) ((NODE)->list.purpose)
#define TREE_VALUE(NODE) ((NODE)->list.value)

struct tree_list
{
  char common[sizeof (struct tree_common)];
  union tree_node *purpose;
  union tree_node *value;
};

/* In a TREE_VEC node.  */
#define TREE_VEC_LENGTH(NODE) ((NODE)->vec.length)
#define TREE_VEC_ELT(NODE,I) ((NODE)->vec.a[I])
#define TREE_VEC_END(NODE) (&((NODE)->vec.a[(NODE)->vec.length]))

struct tree_vec
{
  char common[sizeof (struct tree_common)];
  int length;
  union tree_node *a[1];
};

/* Define fields and accessors for some nodes that represent expressions.  */

/* In a SAVE_EXPR node.  */
#define SAVE_EXPR_CONTEXT(NODE) TREE_OPERAND(NODE, 1)
#define SAVE_EXPR_RTL(NODE) (*(struct rtx_def **) &(NODE)->exp.operands[2])

/* In a RTL_EXPR node.  */
#define RTL_EXPR_SEQUENCE(NODE) (*(struct rtx_def **) &(NODE)->exp.operands[0])
#define RTL_EXPR_RTL(NODE) (*(struct rtx_def **) &(NODE)->exp.operands[1])

/* In a CALL_EXPR node.  */
#define CALL_EXPR_RTL(NODE) (*(struct rtx_def **) &(NODE)->exp.operands[2])

/* In a CONSTRUCTOR node.  */
#define CONSTRUCTOR_ELTS(NODE) TREE_OPERAND (NODE, 1)

/* In ordinary expression nodes.  */
#define TREE_OPERAND(NODE, I) ((NODE)->exp.operands[I])
#define TREE_COMPLEXITY(NODE) ((NODE)->exp.complexity)

struct tree_exp
{
  char common[sizeof (struct tree_common)];
  int complexity;
  union tree_node *operands[1];
};
\f
/* In a BLOCK node.  */
#define BLOCK_VARS(NODE) ((NODE)->block.vars)
#define BLOCK_TYPE_TAGS(NODE) ((NODE)->block.type_tags)
#define BLOCK_SUBBLOCKS(NODE) ((NODE)->block.subblocks)
#define BLOCK_SUPERCONTEXT(NODE) ((NODE)->block.supercontext)
/* Note: when changing this, make sure to find the places
   that use chainon or nreverse.  */
#define BLOCK_CHAIN(NODE) TREE_CHAIN (NODE)
#define BLOCK_ABSTRACT_ORIGIN(NODE) ((NODE)->block.abstract_origin)
#define BLOCK_ABSTRACT(NODE) ((NODE)->block.abstract_flag)
#define BLOCK_END_NOTE(NODE) ((NODE)->block.end_note)

/* Nonzero means that this block is prepared to handle exceptions
   listed in the BLOCK_VARS slot.  */
#define BLOCK_HANDLER_BLOCK(NODE) ((NODE)->block.handler_block_flag)

struct tree_block
{
  char common[sizeof (struct tree_common)];

  unsigned handler_block_flag : 1;
  unsigned abstract_flag : 1;

  union tree_node *vars;
  union tree_node *type_tags;
  union tree_node *subblocks;
  union tree_node *supercontext;
  union tree_node *abstract_origin;
  struct rtx_def *end_note;
};
\f
/* Define fields and accessors for nodes representing data types.  */

/* See tree.def for documentation of the use of these fields.
   Look at the documentation of the various ..._TYPE tree codes.  */

#define TYPE_UID(NODE) ((NODE)->type.uid)
#define TYPE_SIZE(NODE) ((NODE)->type.size)
#define TYPE_MODE(NODE) ((NODE)->type.mode)
#define TYPE_VALUES(NODE) ((NODE)->type.values)
#define TYPE_DOMAIN(NODE) ((NODE)->type.values)
#define TYPE_FIELDS(NODE) ((NODE)->type.values)
#define TYPE_METHODS(NODE) ((NODE)->type.maxval)
#define TYPE_VFIELD(NODE) ((NODE)->type.minval)
#define TYPE_ARG_TYPES(NODE) ((NODE)->type.values)
#define TYPE_METHOD_BASETYPE(NODE) ((NODE)->type.maxval)
#define TYPE_OFFSET_BASETYPE(NODE) ((NODE)->type.maxval)
#define TYPE_POINTER_TO(NODE) ((NODE)->type.pointer_to)
#define TYPE_REFERENCE_TO(NODE) ((NODE)->type.reference_to)
#define TYPE_MIN_VALUE(NODE) ((NODE)->type.minval)
#define TYPE_MAX_VALUE(NODE) ((NODE)->type.maxval)
#define TYPE_PRECISION(NODE) ((NODE)->type.precision)
#define TYPE_PARSE_INFO(NODE) ((NODE)->type.parse_info)
#define TYPE_SYMTAB_ADDRESS(NODE) ((NODE)->type.symtab_address)
#define TYPE_NAME(NODE) ((NODE)->type.name)
#define TYPE_NEXT_VARIANT(NODE) ((NODE)->type.next_variant)
#define TYPE_MAIN_VARIANT(NODE) ((NODE)->type.main_variant)
#define TYPE_BINFO(NODE) ((NODE)->type.binfo)
#define TYPE_NONCOPIED_PARTS(NODE) ((NODE)->type.noncopied_parts)
#define TYPE_CONTEXT(NODE) ((NODE)->type.context)
#define TYPE_LANG_SPECIFIC(NODE) ((NODE)->type.lang_specific)

/* The alignment necessary for objects of this type.
   The value is an int, measured in bits.  */
#define TYPE_ALIGN(NODE) ((NODE)->type.align)

#define TYPE_STUB_DECL(NODE) (TREE_CHAIN (NODE))

/* In a RECORD_TYPE or UNION_TYPE, it means the type has BLKmode
   only because it lacks the alignment requirement for its size.  */
#define TYPE_NO_FORCE_BLK(NODE) ((NODE)->type.no_force_blk_flag)

/* Nonzero in a type considered volatile as a whole.  */
#define TYPE_VOLATILE(NODE) ((NODE)->common.volatile_flag)

/* Means this type is const-qualified.  */
#define TYPE_READONLY(NODE) ((NODE)->common.readonly_flag)

/* These flags are available for each language front end to use internally.  */
#define TYPE_LANG_FLAG_0(NODE) ((NODE)->type.lang_flag_0)
#define TYPE_LANG_FLAG_1(NODE) ((NODE)->type.lang_flag_1)
#define TYPE_LANG_FLAG_2(NODE) ((NODE)->type.lang_flag_2)
#define TYPE_LANG_FLAG_3(NODE) ((NODE)->type.lang_flag_3)
#define TYPE_LANG_FLAG_4(NODE) ((NODE)->type.lang_flag_4)
#define TYPE_LANG_FLAG_5(NODE) ((NODE)->type.lang_flag_5)
#define TYPE_LANG_FLAG_6(NODE) ((NODE)->type.lang_flag_6)

struct tree_type
{
  char common[sizeof (struct tree_common)];
  union tree_node *values;
  union tree_node *size;
  unsigned uid;

#ifdef ONLY_INT_FIELDS
  int mode : 8;
#else
  enum machine_mode mode : 8;
#endif
  unsigned char align;
  unsigned char precision;

  unsigned no_force_blk_flag : 1;
  unsigned lang_flag_0 : 1;
  unsigned lang_flag_1 : 1;
  unsigned lang_flag_2 : 1;
  unsigned lang_flag_3 : 1;
  unsigned lang_flag_4 : 1;
  unsigned lang_flag_5 : 1;
  unsigned lang_flag_6 : 1;

  union tree_node *pointer_to;
  union tree_node *reference_to;
  int parse_info;
  int symtab_address;
  union tree_node *name;
  union tree_node *minval;
  union tree_node *maxval;
  union tree_node *next_variant;
  union tree_node *main_variant;
  union tree_node *binfo;
  union tree_node *noncopied_parts;
  union tree_node *context;
  /* Points to a structure whose details depend on the language in use.  */
  struct lang_type *lang_specific;
};
\f
/* Define accessor macros for information about type inheritance
   and basetypes.

   A "basetype" means a particular usage of a data type for inheritance
   in another type.  Each such basetype usage has its own "binfo"
   object to describe it.  The binfo object is a TREE_VEC node.

   Inheritance is represented by the binfo nodes allocated for a
   given type.  For example, given types C and D, such that D is
   inherited by C, 3 binfo nodes will be allocated: one for describing
   the binfo properties of C, similarly one for D, and one for
   describing the binfo properties of D as a base type for C.
   Thus, given a pointer to class C, one can get a pointer to the binfo
   of D acting as a basetype for C by looking at C's binfo's basetypes.  */

/* The actual data type node being inherited in this basetype.  */
#define BINFO_TYPE(NODE) TREE_TYPE (NODE)

/* The offset where this basetype appears in its containing type.
   BINFO_OFFSET slot holds the offset (in bytes)
   from the base of the complete object to the base of the part of the
   object that is allocated on behalf of this `type'.
   This is always 0 except when there is multiple inheritance.  */
   
#define BINFO_OFFSET(NODE) TREE_VEC_ELT ((NODE), 1)
#define TYPE_BINFO_OFFSET(NODE) BINFO_OFFSET (TYPE_BINFO (NODE))
#define BINFO_OFFSET_ZEROP(NODE) (BINFO_OFFSET (NODE) == integer_zero_node)

/* The virtual function table belonging to this basetype.  Virtual
   function tables provide a mechanism for run-time method dispatching.
   The entries of a virtual function table are language-dependent.  */

#define BINFO_VTABLE(NODE) TREE_VEC_ELT ((NODE), 2)
#define TYPE_BINFO_VTABLE(NODE) BINFO_VTABLE (TYPE_BINFO (NODE))

/* The virtual functions in the virtual function table.  This is
   a TREE_LIST that is used as an initial approximation for building
   a virtual function table for this basetype.  */
#define BINFO_VIRTUALS(NODE) TREE_VEC_ELT ((NODE), 3)
#define TYPE_BINFO_VIRTUALS(NODE) BINFO_VIRTUALS (TYPE_BINFO (NODE))

/* A vector of additional binfos for the types inherited by this basetype.

   If this basetype describes type D as inherited in C,
   and if the basetypes of D are E anf F,
   then this vector contains binfos for inheritance of E and F by C.

   ??? This could probably be done by just allocating the
   base types at the end of this TREE_VEC (instead of using
   another TREE_VEC).  This would simplify the calculation
   of how many basetypes a given type had.  */
#define BINFO_BASETYPES(NODE) TREE_VEC_ELT ((NODE), 4)
#define TYPE_BINFO_BASETYPES(NODE) TREE_VEC_ELT (TYPE_BINFO (NODE), 4)

/* Accessor macro to get to the Nth basetype of this basetype.  */
#define BINFO_BASETYPE(NODE,N) TREE_VEC_ELT (BINFO_BASETYPES (NODE), (N))
#define TYPE_BINFO_BASETYPE(NODE,N) BINFO_TYPE (TREE_VEC_ELT (BINFO_BASETYPES (TYPE_BINFO (NODE)), (N)))

/* Slot used to build a chain that represents a use of inheritance.
   For example, if X is derived from Y, and Y is derived from Z,
   then this field can be used to link the binfo node for X to
   the binfo node for X's Y to represent the use of inheritance
   from X to Y.  Similarly, this slot of the binfo node for X's Y
   can point to the Z from which Y is inherited (in X's inheritance
   hierarchy).  In this fashion, one can represent and traverse specific
   uses of inheritance using the binfo nodes themselves (instead of
   consing new space pointing to binfo nodes).
   It is up to the language-dependent front-ends to maintain
   this information as necessary.  */
#define BINFO_INHERITANCE_CHAIN(NODE) TREE_VEC_ELT ((NODE), 0)
\f
/* Define fields and accessors for nodes representing declared names.  */

/* This is the name of the object as written by the user.
   It is an IDENTIFIER_NODE.  */
#define DECL_NAME(NODE) ((NODE)->decl.name)
/* This macro is marked for death.  */
#define DECL_PRINT_NAME(NODE) ((NODE)->decl.print_name)
/* This is the name of the object as the assembler will see it
   (but before any translations made by ASM_OUTPUT_LABELREF).
   Often this is the same as DECL_NAME.
   It is an IDENTIFIER_NODE.  */
#define DECL_ASSEMBLER_NAME(NODE) ((NODE)->decl.assembler_name)
/*  For FIELD_DECLs, this is the
    RECORD_TYPE or UNION_TYPE node that the field is a member of.  For
    VAR_DECL, PARM_DECL, FUNCTION_DECL, LABEL_DECL, and CONST_DECL nodes,
    this points to the FUNCTION_DECL for the containing function, or else
    yields NULL_TREE if the given decl has "file scope".  */
#define DECL_CONTEXT(NODE) ((NODE)->decl.context)
#define DECL_FIELD_CONTEXT(NODE) ((NODE)->decl.context)
/* In a FIELD_DECL, this is the field position, counting in bits,
   of the bit closest to the beginning of the structure.  */
#define DECL_FIELD_BITPOS(NODE) ((NODE)->decl.arguments)
/* In a FIELD_DECL, this indicates whether the field was a bit-field and
   if so, the type that was originally specified for it.
   TREE_TYPE may have been modified (in finish_struct).  */
#define DECL_BIT_FIELD_TYPE(NODE) ((NODE)->decl.result)
/* In FUNCTION_DECL, a chain of ..._DECL nodes.  */
/* VAR_DECL and PARM_DECL reserve the arguments slot
   for language-specific uses.  */
#define DECL_ARGUMENTS(NODE) ((NODE)->decl.arguments)
/* In FUNCTION_DECL, holds the decl for the return value.  */
#define DECL_RESULT(NODE) ((NODE)->decl.result)
/* In PARM_DECL, holds the type as written (perhaps a function or array).  */
#define DECL_ARG_TYPE_AS_WRITTEN(NODE) ((NODE)->decl.result)
/* For a FUNCTION_DECL, holds the tree of BINDINGs.
   For a VAR_DECL, holds the initial value.
   For a PARM_DECL, not used--default
   values for parameters are encoded in the type of the function,
   not in the PARM_DECL slot.  */
#define DECL_INITIAL(NODE) ((NODE)->decl.initial)
/* For a PARM_DECL, records the data type used to pass the argument,
   which may be different from the type seen in the program.  */
#define DECL_ARG_TYPE(NODE) ((NODE)->decl.initial)   /* In PARM_DECL.  */
/* These two fields describe where in the source code the declaration was.  */
#define DECL_SOURCE_FILE(NODE) ((NODE)->decl.filename)
#define DECL_SOURCE_LINE(NODE) ((NODE)->decl.linenum)
/* Holds the size of the datum, as a tree expression.
   Need not be constant.  */
#define DECL_SIZE(NODE) ((NODE)->decl.size)
/* Holds the alignment required for the datum.  */
#define DECL_ALIGN(NODE) ((NODE)->decl.frame_size)
/* Holds the machine mode of a variable or field.  */
#define DECL_MODE(NODE) ((NODE)->decl.mode)
/* Holds the RTL expression for the value of a variable or function.  */
#define DECL_RTL(NODE) ((NODE)->decl.rtl)
/* For PARM_DECL, holds an RTL for the stack slot or register
   where the data was actually passed.  */
#define DECL_INCOMING_RTL(NODE) ((NODE)->decl.saved_insns.r)
/* For FUNCTION_DECL, if it is inline, holds the saved insn chain.  */
#define DECL_SAVED_INSNS(NODE) ((NODE)->decl.saved_insns.r)
/* For FUNCTION_DECL, if it is inline,
   holds the size of the stack frame, as an integer.  */
#define DECL_FRAME_SIZE(NODE) ((NODE)->decl.frame_size)
/* For FUNCTION_DECL, if it is built-in,
   this identifies which built-in operation it is.  */
#define DECL_FUNCTION_CODE(NODE) \
 ((enum built_in_function) (NODE)->decl.frame_size)
#define DECL_SET_FUNCTION_CODE(NODE,VAL) \
 ((NODE)->decl.frame_size = (int) (VAL))
/* For a FIELD_DECL, holds the size of the member as an integer.  */
#define DECL_FIELD_SIZE(NODE) ((NODE)->decl.saved_insns.i)

/* The DECL_VINDEX is used for FUNCTION_DECLS in two different ways.
   Before the struct containing the FUNCTION_DECL is laid out,
   DECL_VINDEX may point to a FUNCTION_DECL in a base class which
   is the FUNCTION_DECL which this FUNCTION_DECL will replace as a virtual
   function.  When the class is laid out, this pointer is changed
   to an INTEGER_CST node which is suitable for use as an index
   into the virtual function table.  */
#define DECL_VINDEX(NODE) ((NODE)->decl.vindex)
/* For FIELD_DECLS, DECL_FCONTEXT is the *first* baseclass in
   which this FIELD_DECL is defined.  This information is needed when
   writing debugging information about vfield and vbase decls for C++.  */
#define DECL_FCONTEXT(NODE) ((NODE)->decl.vindex)

/* Every ..._DECL node gets a unique number.  */
#define DECL_UID(NODE) ((NODE)->decl.uid)

/* For any sort of a ..._DECL node, this points to the original (abstract)
   decl node which this decl is an instance of, or else it is NULL indicating
   that this decl is not an instance of some other decl.  */
#define DECL_ABSTRACT_ORIGIN(NODE) ((NODE)->decl.abstract_origin)

/* Nonzero for any sort of ..._DECL node means this decl node represents
   an inline instance of some original (abstract) decl from an inline function;
   suppress any warnings about shadowing some other variable.  */
#define DECL_FROM_INLINE(NODE) (DECL_ABSTRACT_ORIGIN (NODE) != (tree) 0)

/* Nonzero if a _DECL means that the name of this decl should be ignored
   for symbolic debug purposes.  */
#define DECL_IGNORED_P(NODE) ((NODE)->decl.ignored_flag)

/* Nonzero for a given ..._DECL node means that this node represents an
   "abstract instance" of the given declaration (e.g. in the original
   declaration of an inline function).  When generating symbolic debugging
   information, we musn't try to generate any address information for nodes
   marked as "abstract instances" because we don't actually generate
   any code or allocate any data space for such instances.  */
#define DECL_ABSTRACT(NODE) ((NODE)->decl.abstract_flag)

/* Nonzero if a _DECL means that no warnings should be generated just
   because this decl is unused.  */
#define DECL_IN_SYSTEM_HEADER(NODE) ((NODE)->decl.in_system_header_flag)

/* Language-specific decl information.  */
#define DECL_LANG_SPECIFIC(NODE) ((NODE)->decl.lang_specific)

/* In a VAR_DECL or FUNCTION_DECL,
   nonzero means external reference:
   do not allocate storage, and refer to a definition elsewhere.  */
#define DECL_EXTERNAL(NODE) ((NODE)->decl.external_flag)

/* In VAR_DECL and PARM_DECL nodes, nonzero means declared `register'.
   In LABEL_DECL nodes, nonzero means that an error message about
   jumping into such a binding contour has been printed for this label.  */
#define DECL_REGISTER(NODE) ((NODE)->decl.regdecl_flag)
/* In a FIELD_DECL, indicates this field should be bit-packed.  */
#define DECL_PACKED(NODE) ((NODE)->decl.regdecl_flag)

/* Nonzero in a ..._DECL means this variable is ref'd from a nested function.
   For VAR_DECL nodes, PARM_DECL nodes, and FUNCTION_DECL nodes.

   For LABEL_DECL nodes, nonzero if nonlocal gotos to the label are permitted.

   Also set in some languages for variables, etc., outside the normal
   lexical scope, such as class instance variables.  */
#define DECL_NONLOCAL(NODE) ((NODE)->decl.nonlocal_flag)

/* Nonzero in a FUNCTION_DECL means this function can be substituted
   where it is called.  */
#define DECL_INLINE(NODE) ((NODE)->decl.inline_flag)

/* Nonzero in a FUNCTION_DECL means this is a built-in function
   that is not specified by ansi C and that users are supposed to be allowed
   to redefine for any purpose whatever.  */
#define DECL_BUILT_IN_NONANSI(NODE) ((NODE)->common.unsigned_flag)

/* Nonzero in a FIELD_DECL means it is a bit field, and must be accessed
   specially.  */
#define DECL_BIT_FIELD(NODE) ((NODE)->decl.bit_field_flag)
/* In a LABEL_DECL, nonzero means label was defined inside a binding
   contour that restored a stack level and which is now exited.  */
#define DECL_TOO_LATE(NODE) ((NODE)->decl.bit_field_flag)
/* In a FUNCTION_DECL, nonzero means a built in function.  */
#define DECL_BUILT_IN(NODE) ((NODE)->decl.bit_field_flag)

/* Used in VAR_DECLs to indicate that the variable is a vtable.
   It is also used in FIELD_DECLs for vtable pointers.  */
#define DECL_VIRTUAL_P(NODE) ((NODE)->decl.virtual_flag)

/* Additional flags for language-specific uses.  */
#define DECL_LANG_FLAG_0(NODE) ((NODE)->decl.lang_flag_0)
#define DECL_LANG_FLAG_1(NODE) ((NODE)->decl.lang_flag_1)
#define DECL_LANG_FLAG_2(NODE) ((NODE)->decl.lang_flag_2)
#define DECL_LANG_FLAG_3(NODE) ((NODE)->decl.lang_flag_3)
#define DECL_LANG_FLAG_4(NODE) ((NODE)->decl.lang_flag_4)
#define DECL_LANG_FLAG_5(NODE) ((NODE)->decl.lang_flag_5)
#define DECL_LANG_FLAG_6(NODE) ((NODE)->decl.lang_flag_6)
#define DECL_LANG_FLAG_7(NODE) ((NODE)->decl.lang_flag_7)

struct tree_decl
{
  char common[sizeof (struct tree_common)];
  char *filename;
  int linenum;
  union tree_node *size;
  unsigned int uid;
#ifdef ONLY_INT_FIELDS
  int mode : 8;
#else
  enum machine_mode mode : 8;
#endif

  unsigned external_flag : 1;
  unsigned nonlocal_flag : 1;
  unsigned regdecl_flag : 1;
  unsigned inline_flag : 1;
  unsigned bit_field_flag : 1;
  unsigned virtual_flag : 1;
  unsigned ignored_flag : 1;
  unsigned abstract_flag : 1;

  unsigned in_system_header_flag : 1;
  /* room for seven more */

  unsigned lang_flag_0 : 1;
  unsigned lang_flag_1 : 1;
  unsigned lang_flag_2 : 1;
  unsigned lang_flag_3 : 1;
  unsigned lang_flag_4 : 1;
  unsigned lang_flag_5 : 1;
  unsigned lang_flag_6 : 1;
  unsigned lang_flag_7 : 1;

  union tree_node *name;
  union tree_node *context;
  union tree_node *arguments;
  union tree_node *result;
  union tree_node *initial;
  union tree_node *abstract_origin;
  /* The PRINT_NAME field is marked for death.  */
  char *print_name;
  union tree_node *assembler_name;
  struct rtx_def *rtl;  /* acts as link to register transfer language
                                   (rtl) info */
  /* For a FUNCTION_DECL, if inline, this is the size of frame needed.
     If built-in, this is the code for which built-in function.
     For other kinds of decls, this is DECL_ALIGN.  */
  int frame_size;
  /* For FUNCTION_DECLs: points to insn that constitutes its definition
     on the permanent obstack.  For any other kind of decl, this is the
     alignment.  */
  union {
    struct rtx_def *r;
    int i;
  } saved_insns;
  union tree_node *vindex;
  /* Points to a structure whose details depend on the language in use.  */
  struct lang_decl *lang_specific;
};
\f
/* Define the overall contents of a tree node.
   It may be any of the structures declared above
   for various types of node.  */

union tree_node
{
  struct tree_common common;
  struct tree_int_cst int_cst;
  struct tree_real_cst real_cst;
  struct tree_string string;
  struct tree_complex complex;
  struct tree_identifier identifier;
  struct tree_decl decl;
  struct tree_type type;
  struct tree_list list;
  struct tree_vec vec;
  struct tree_exp exp;
  struct tree_block block;
 };

/* Add prototype support.  */
#ifndef PROTO
#if defined (USE_PROTOTYPES) ? USE_PROTOTYPES : defined (__STDC__)
#define PROTO(ARGS) ARGS
#else
#define PROTO(ARGS) ()
#endif
#endif


#define NULL_TREE (tree) NULL

/* Define a generic NULL if one hasn't already been defined.  */

#ifndef NULL
#define NULL 0
#endif

#ifndef GENERIC_PTR
#if defined (USE_PROTOTYPES) ? USE_PROTOTYPES : defined (__STDC__)
#define GENERIC_PTR void *
#else
#define GENERIC_PTR char *
#endif
#endif

#ifndef NULL_PTR
#define NULL_PTR ((GENERIC_PTR)0)
#endif

/* Format for global names of constructor and destructor functions.  */
#ifndef NO_DOLLAR_IN_LABEL
#define CONSTRUCTOR_NAME_FORMAT "_GLOBAL_$I$%s"
#else
#define CONSTRUCTOR_NAME_FORMAT "_GLOBAL_.I.%s"
#endif
\f
/* The following functions accept a wide integer argument.  Rather than
   having to cast on every function call, we use a macro instead, that is
   defined here and in rtl.h.  */

#ifndef exact_log2
#define exact_log2(N) exact_log2_wide ((HOST_WIDE_INT) (N))
#define floor_log2(N) floor_log2_wide ((HOST_WIDE_INT) (N))
#endif

#if 0
/* At present, don't prototype xrealloc, since all of the callers don't
   cast their pointers to char *, and all of the xrealloc's don't use
   void * yet.  */
extern char *xrealloc                   PROTO((void *, unsigned));
#else
extern char *xrealloc ();
#endif

extern char *oballoc                    PROTO((int));
extern char *permalloc                  PROTO((int));
extern char *savealloc                  PROTO((int));
extern char *xmalloc                    PROTO((unsigned));
extern void free                        PROTO((void *));

/* Lowest level primitive for allocating a node.
   The TREE_CODE is the only argument.  Contents are initialized
   to zero except for a few of the common fields.  */

extern tree make_node                   PROTO((enum tree_code));

/* Make a copy of a node, with all the same contents except
   for TREE_PERMANENT.  (The copy is permanent
   iff nodes being made now are permanent.)  */

extern tree copy_node                   PROTO((tree));

/* Make a copy of a chain of TREE_LIST nodes.  */

extern tree copy_list                   PROTO((tree));

/* Make a TREE_VEC.  */

extern tree make_tree_vec               PROTO((int));

/* Return the (unique) IDENTIFIER_NODE node for a given name.
   The name is supplied as a char *.  */

extern tree get_identifier              PROTO((char *));

/* Construct various types of nodes.  */

#define build_int_2(LO,HI)  \
  build_int_2_wide ((HOST_WIDE_INT) (LO), (HOST_WIDE_INT) (HI))

#if 0
/* We cannot define prototypes for the variable argument functions,
   since they have not been ANSI-fied, and an ANSI compiler would
   complain when compiling the definition of these functions.  */

extern tree build                       PROTO((enum tree_code, tree, ...));
extern tree build_nt                    PROTO((enum tree_code, ...));
extern tree build_parse_node            PROTO((enum tree_code, ...));
#else
extern tree build ();
extern tree build_nt ();
extern tree build_parse_node ();
#endif

extern tree build_int_2_wide            PROTO((HOST_WIDE_INT, HOST_WIDE_INT));
extern tree build_real                  PROTO((tree, REAL_VALUE_TYPE));
extern tree build_real_from_int_cst     PROTO((tree, tree));
extern tree build_complex               PROTO((tree, tree));
extern tree build_string                PROTO((int, char *));
extern tree build1                      PROTO((enum tree_code, tree, tree));
extern tree build_tree_list             PROTO((tree, tree));
extern tree build_decl_list             PROTO((tree, tree));
extern tree build_decl                  PROTO((enum tree_code, tree, tree));
extern tree build_block                 PROTO((tree, tree, tree, tree, tree));

/* Construct various nodes representing data types.  */

extern tree make_signed_type            PROTO((int));
extern tree make_unsigned_type          PROTO((int));
extern tree signed_or_unsigned_type     PROTO((int, tree));
extern void fixup_unsigned_type         PROTO((tree));
extern tree build_pointer_type          PROTO((tree));
extern tree build_reference_type        PROTO((tree));
extern tree build_index_type            PROTO((tree));
extern tree build_index_2_type          PROTO((tree, tree));
extern tree build_array_type            PROTO((tree, tree));
extern tree build_function_type         PROTO((tree, tree));
extern tree build_method_type           PROTO((tree, tree));
extern tree build_offset_type           PROTO((tree, tree));
extern tree build_complex_type          PROTO((tree));
extern tree array_type_nelts            PROTO((tree));

/* Construct expressions, performing type checking.
   GCC and G++ use different calling sequences for build_binary_op,
   and build_indirect_ref, so don't include a prototype here.  */

extern tree build_binary_op ();
extern tree build_indirect_ref ();
extern tree build_unary_op              PROTO((enum tree_code, tree, int));

/* From expmed.c.  Since rtl.h is included after tree.h, we can't
   put the prototype here.  Rtl.h does declare the prototype if
   tree.h had been included.  */

extern tree make_tree ();
\f
/* Given a type node TYPE, and CONSTP and VOLATILEP, return a type
   for the same kind of data as TYPE describes.
   Variants point to the "main variant" (which has neither CONST nor VOLATILE)
   via TYPE_MAIN_VARIANT, and it points to a chain of other variants
   so that duplicate variants are never made.
   Only main variants should ever appear as types of expressions.  */

extern tree build_type_variant          PROTO((tree, int, int));

/* Make a copy of a type node.  */

extern tree build_type_copy             PROTO((tree));

/* Given a ..._TYPE node, calculate the TYPE_SIZE, TYPE_SIZE_UNIT,
   TYPE_ALIGN and TYPE_MODE fields.
   If called more than once on one node, does nothing except
   for the first time.  */

extern void layout_type                 PROTO((tree));

/* Given a hashcode and a ..._TYPE node (for which the hashcode was made),
   return a canonicalized ..._TYPE node, so that duplicates are not made.
   How the hash code is computed is up to the caller, as long as any two
   callers that could hash identical-looking type nodes agree.  */

extern tree type_hash_canon             PROTO((int, tree));

/* Given a VAR_DECL, PARM_DECL, RESULT_DECL or FIELD_DECL node,
   calculates the DECL_SIZE, DECL_SIZE_UNIT, DECL_ALIGN and DECL_MODE
   fields.  Call this only once for any given decl node.

   Second argument is the boundary that this field can be assumed to
   be starting at (in bits).  Zero means it can be assumed aligned
   on any boundary that may be needed.  */

extern void layout_decl                 PROTO((tree, unsigned));

/* Fold constants as much as possible in an expression.
   Returns the simplified expression.
   Acts only on the top level of the expression;
   if the argument itself cannot be simplified, its
   subexpressions are not changed.  */

extern tree fold                        PROTO((tree));

/* Return an expr equal to X but certainly not valid as an lvalue.  */

extern tree non_lvalue                  PROTO((tree));

extern tree convert                     PROTO((tree, tree));
extern tree size_in_bytes               PROTO((tree));
extern int int_size_in_bytes            PROTO((tree));
extern tree size_binop                  PROTO((enum tree_code, tree, tree));
extern tree size_int                    PROTO((unsigned));
extern tree round_up                    PROTO((tree, int));
extern tree get_pending_sizes           PROTO((void));

/* Type for sizes of data-type.  */

extern tree sizetype;

/* Concatenate two lists (chains of TREE_LIST nodes) X and Y
   by making the last node in X point to Y.
   Returns X, except if X is 0 returns Y.  */

extern tree chainon                     PROTO((tree, tree));

/* Make a new TREE_LIST node from specified PURPOSE, VALUE and CHAIN.  */

extern tree tree_cons                   PROTO((tree, tree, tree));
extern tree perm_tree_cons              PROTO((tree, tree, tree));
extern tree temp_tree_cons              PROTO((tree, tree, tree));
extern tree saveable_tree_cons          PROTO((tree, tree, tree));
extern tree decl_tree_cons              PROTO((tree, tree, tree));

/* Return the last tree node in a chain.  */

extern tree tree_last                   PROTO((tree));

/* Reverse the order of elements in a chain, and return the new head.  */

extern tree nreverse                    PROTO((tree));

/* Returns the length of a chain of nodes
   (number of chain pointers to follow before reaching a null pointer).  */

extern int list_length                  PROTO((tree));

/* integer_zerop (tree x) is nonzero if X is an integer constant of value 0 */

extern int integer_zerop                PROTO((tree));

/* integer_onep (tree x) is nonzero if X is an integer constant of value 1 */

extern int integer_onep                 PROTO((tree));

/* integer_all_onesp (tree x) is nonzero if X is an integer constant
   all of whose significant bits are 1.  */

extern int integer_all_onesp            PROTO((tree));

/* integer_pow2p (tree x) is nonzero is X is an integer constant with
   exactly one bit 1.  */

extern int integer_pow2p                PROTO((tree));

/* staticp (tree x) is nonzero if X is a reference to data allocated
   at a fixed address in memory.  */

extern int staticp                      PROTO((tree));

/* Gets an error if argument X is not an lvalue.
   Also returns 1 if X is an lvalue, 0 if not.  */

extern int lvalue_or_else               PROTO((tree, char *));

/* save_expr (EXP) returns an expression equivalent to EXP
   but it can be used multiple times within context CTX
   and only evaluate EXP once.  */

extern tree save_expr                   PROTO((tree));

/* variable_size (EXP) is like save_expr (EXP) except that it
   is for the special case of something that is part of a
   variable size for a data type.  It makes special arrangements
   to compute the value at the right time when the data type
   belongs to a function parameter.  */

extern tree variable_size               PROTO((tree));

/* stabilize_reference (EXP) returns an reference equivalent to EXP
   but it can be used multiple times
   and only evaluate the subexpressions once.  */

extern tree stabilize_reference         PROTO((tree));

/* Return EXP, stripped of any conversions to wider types
   in such a way that the result of converting to type FOR_TYPE
   is the same as if EXP were converted to FOR_TYPE.
   If FOR_TYPE is 0, it signifies EXP's type.  */

extern tree get_unwidened               PROTO((tree, tree));

/* Return OP or a simpler expression for a narrower value
   which can be sign-extended or zero-extended to give back OP.
   Store in *UNSIGNEDP_PTR either 1 if the value should be zero-extended
   or 0 if the value should be sign-extended.  */

extern tree get_narrower                PROTO((tree, int *));

/* Given MODE and UNSIGNEDP, return a suitable type-tree
   with that mode.
   The definition of this resides in language-specific code
   as the repertoire of available types may vary.  */

extern tree type_for_mode               PROTO((enum machine_mode, int));

/* Given PRECISION and UNSIGNEDP, return a suitable type-tree
   for an integer type with at least that precision.
   The definition of this resides in language-specific code
   as the repertoire of available types may vary.  */

extern tree type_for_size               PROTO((unsigned, int));

/* Given an integer type T, return a type like T but unsigned.
   If T is unsigned, the value is T.
   The definition of this resides in language-specific code
   as the repertoire of available types may vary.  */

extern tree unsigned_type               PROTO((tree));

/* Given an integer type T, return a type like T but signed.
   If T is signed, the value is T.
   The definition of this resides in language-specific code
   as the repertoire of available types may vary.  */

extern tree signed_type                 PROTO((tree));

/* This function must be defined in the language-specific files.
   expand_expr calls it to build the cleanup-expression for a TARGET_EXPR.
   This is defined in a language-specific file.  */

extern tree maybe_build_cleanup         PROTO((tree));

/* Given an expression EXP that may be a COMPONENT_REF or an ARRAY_REF,
   look for nested component-refs or array-refs at constant positions
   and find the ultimate containing object, which is returned.  */

extern tree get_inner_reference         PROTO((tree, int *, int *, tree *, enum machine_mode *, int *, int *));

/* Return the FUNCTION_DECL which provides this _DECL with its context,
   or zero if none.  */
extern tree decl_function_context       PROTO((tree));

/* Return the RECORD_TYPE or UNION_TYPE which provides this _DECL
   with its context, or zero if none.  */
extern tree decl_type_context           PROTO((tree));

/* Given the FUNCTION_DECL for the current function,
   return zero if it is ok for this function to be inline.
   Otherwise return a warning message with a single %s
   for the function's name.  */

extern char *function_cannot_inline_p   PROTO((tree));
\f
/* Declare commonly used variables for tree structure.  */

/* An integer constant with value 0 */
extern tree integer_zero_node;

/* An integer constant with value 1 */
extern tree integer_one_node;

/* An integer constant with value 0 whose type is sizetype.  */
extern tree size_zero_node;

/* An integer constant with value 1 whose type is sizetype.  */
extern tree size_one_node;

/* A constant of type pointer-to-int and value 0 */
extern tree null_pointer_node;

/* A node of type ERROR_MARK.  */
extern tree error_mark_node;

/* The type node for the void type.  */
extern tree void_type_node;

/* The type node for the ordinary (signed) integer type.  */
extern tree integer_type_node;

/* The type node for the unsigned integer type.  */
extern tree unsigned_type_node;

/* The type node for the ordinary character type.  */
extern tree char_type_node;

/* Points to the name of the input file from which the current input
   being parsed originally came (before it went into cpp).  */
extern char *input_filename;

/* Current line number in input file.  */
extern int lineno;

/* Nonzero for -pedantic switch: warn about anything
   that standard C forbids.  */
extern int pedantic;

/* Nonzero means can safely call expand_expr now;
   otherwise layout_type puts variable sizes onto `pending_sizes' instead.  */

extern int immediate_size_expand;

/* Points to the FUNCTION_DECL of the function whose body we are reading. */

extern tree current_function_decl;

/* Nonzero if function being compiled can call setjmp.  */

extern int current_function_calls_setjmp;

/* Nonzero if function being compiled can call longjmp.  */

extern int current_function_calls_longjmp;

/* Nonzero means all ..._TYPE nodes should be allocated permanently.  */

extern int all_types_permanent;

/* Pointer to function to compute the name to use to print a declaration.  */

extern char *(*decl_printable_name) ();
\f
/* In stmt.c */

extern tree expand_start_stmt_expr              PROTO((void));
extern tree expand_end_stmt_expr                PROTO((tree));
extern void expand_expr_stmt                    PROTO((tree));
extern void clear_last_expr                     PROTO((void));
extern void expand_label                        PROTO((tree));
extern void expand_goto                         PROTO((tree));
extern void expand_asm                          PROTO((tree));
extern void expand_start_cond                   PROTO((tree, int));
extern void expand_end_cond                     PROTO((void));
extern void expand_start_else                   PROTO((void));
extern void expand_start_elseif                 PROTO((tree));
extern struct nesting *expand_start_loop        PROTO((int));
extern struct nesting *expand_start_loop_continue_elsewhere     PROTO((int));
extern void expand_loop_continue_here           PROTO((void));
extern void expand_end_loop                     PROTO((void));
extern int expand_continue_loop                 PROTO((struct nesting *));
extern int expand_exit_loop                     PROTO((struct nesting *));
extern int expand_exit_loop_if_false            PROTO((struct nesting *, tree));
extern int expand_exit_something                PROTO((void));

extern void expand_null_return                  PROTO((void));
extern void expand_return                       PROTO((tree));
extern void expand_start_bindings               PROTO((int));
extern void expand_end_bindings                 PROTO((tree, int, int));
extern tree last_cleanup_this_contour           PROTO((void));
extern void expand_start_case                   PROTO((int, tree, tree, char *));
extern void expand_end_case                     PROTO((tree));
extern int pushcase                             PROTO((tree, tree, tree *));
extern int pushcase_range                       PROTO((tree, tree, tree, tree *));

/* In fold-const.c */

extern tree invert_truthvalue                   PROTO((tree));
\f
/* The language front-end must define these functions.  */

/* Function of no arguments for initializing lexical scanning.  */
extern void init_lex                            PROTO((void));
/* Function of no arguments for initializing the symbol table.  */
extern void init_decl_processing                PROTO((void));

/* Functions called with no arguments at the beginning and end or processing
   the input source file.  */
extern void lang_init                           PROTO((void));
extern void lang_finish                         PROTO((void));

/* Function called with no arguments to parse and compile the input.  */
extern int yyparse                              PROTO((void));
/* Function called with option as argument
   to decode options starting with -f or -W or +.
   It should return nonzero if it handles the option.  */
extern int lang_decode_option                   PROTO((char *));

/* Functions for processing symbol declarations.  */
/* Function to enter a new lexical scope.
   Takes one argument: always zero when called from outside the front end.  */
extern void pushlevel                           PROTO((int));
/* Function to exit a lexical scope.  It returns a BINDING for that scope.
   Takes three arguments:
     KEEP -- nonzero if there were declarations in this scope.
     REVERSE -- reverse the order of decls before returning them.
     FUNCTIONBODY -- nonzero if this level is the body of a function.  */
extern tree poplevel                            PROTO((int, int, int));
/* Return the BLOCK node for the current scope level.  */
extern tree current_block                       PROTO((void));
/* Function to add a decl to the current scope level.
   Takes one argument, a decl to add.
   Returns that decl, or, if the same symbol is already declared, may
   return a different decl for that name.  */
extern tree pushdecl                            PROTO((tree));
/* Function to return the chain of decls so far in the current scope level.  */
extern tree getdecls                            PROTO((void));
/* Function to return the chain of structure tags in the current scope level.  */
extern tree gettags                             PROTO((void));