lex.c

gcc库的原代码,对编程有很大帮助.

/* Separate lexical analyzer for GNU C++.
   Copyright (C) 1987, 89, 92, 93, 94, 1995 Free Software Foundation, Inc.
   Hacked by Michael Tiemann ([e-mail])

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, 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.  */


/* This file is the lexical analyzer for GNU C++.  */

/* Cause the `yydebug' variable to be defined.  */
#define YYDEBUG 1

#include <sys/types.h>
#include <stdio.h>
#include <errno.h>
#include <setjmp.h>
#include "config.h"
#include "input.h"
#include "tree.h"
#include "lex.h"
#include "parse.h"
#include "cp-tree.h"
#include "flags.h"
#include "obstack.h"
#include "c-pragma.h"

#ifdef MULTIBYTE_CHARS
#include <stdlib.h>
#include <locale.h>
#endif

#ifndef errno
extern int errno;		/* needed for VAX.  */
#endif
extern jmp_buf toplevel;

#define obstack_chunk_alloc xmalloc
#define obstack_chunk_free free

extern struct obstack *expression_obstack, permanent_obstack;
extern struct obstack *current_obstack, *saveable_obstack;

extern double atof ();

extern char *get_directive_line ();	/* In c-common.c */

/* Given a file name X, return the nondirectory portion.
   Keep in mind that X can be computed more than once.  */
#ifndef FILE_NAME_NONDIRECTORY
#define FILE_NAME_NONDIRECTORY(X)		\
 (rindex (X, '/') != 0 ? rindex (X, '/') + 1 : X)
#endif

extern char *index ();
extern char *rindex ();

void extract_interface_info ();
void yyerror ();

/* This obstack is needed to hold text.  It is not safe to use
   TOKEN_BUFFER because `check_newline' calls `yylex'.  */
struct obstack inline_text_obstack;
static char *inline_text_firstobj;

/* This obstack is used to hold information about methods to be
   synthesized.  It should go away when synthesized methods are handled
   properly (i.e. only when needed).  */
struct obstack synth_obstack;
static char *synth_firstobj;

int end_of_file;

/* Pending language change.
   Positive is push count, negative is pop count.  */
int pending_lang_change = 0;

/* Wrap the current header file in extern "C".  */
static int c_header_level = 0;

extern int first_token;
extern struct obstack token_obstack;

/* ??? Don't really know where this goes yet.  */
#if 1
#include "input.c"
#else
extern void put_back (/* int */);
extern int input_redirected ();
extern void feed_input (/* char *, int, struct obstack * */);
#endif

/* Holds translations from TREE_CODEs to operator name strings,
   i.e., opname_tab[PLUS_EXPR] == "+".  */
char **opname_tab;
char **assignop_tab;

extern int yychar;		/*  the lookahead symbol		*/
extern YYSTYPE yylval;		/*  the semantic value of the		*/
				/*  lookahead symbol			*/

#if 0
YYLTYPE yylloc;			/*  location data for the lookahead	*/
				/*  symbol				*/
#endif


/* the declaration found for the last IDENTIFIER token read in.
   yylex must look this up to detect typedefs, which get token type TYPENAME,
   so it is left around in case the identifier is not a typedef but is
   used in a context which makes it a reference to a variable.  */
tree lastiddecl;

/* The elements of `ridpointers' are identifier nodes
   for the reserved type names and storage classes.
   It is indexed by a RID_... value.  */
tree ridpointers[(int) RID_MAX];

/* We may keep statistics about how long which files took to compile.  */
static int header_time, body_time;
static tree get_time_identifier ();
static tree filename_times;
static tree this_filename_time;

/* For implementing #pragma unit.  */
tree current_unit_name;
tree current_unit_language;

/* Array for holding counts of the numbers of tokens seen.  */
extern int *token_count;

/* Textual definition used for default functions.  */
static void default_copy_constructor_body ();
static void default_assign_ref_body ();

/* Return something to represent absolute declarators containing a *.
   TARGET is the absolute declarator that the * contains.
   TYPE_QUALS is a list of modifiers such as const or volatile
   to apply to the pointer type, represented as identifiers.

   We return an INDIRECT_REF whose "contents" are TARGET
   and whose type is the modifier list.  */

tree
make_pointer_declarator (type_quals, target)
     tree type_quals, target;
{
  if (target && TREE_CODE (target) == IDENTIFIER_NODE
      && ANON_AGGRNAME_P (target))
    error ("type name expected before `*'");
  target = build_parse_node (INDIRECT_REF, target);
  TREE_TYPE (target) = type_quals;
  return target;
}

/* Return something to represent absolute declarators containing a &.
   TARGET is the absolute declarator that the & contains.
   TYPE_QUALS is a list of modifiers such as const or volatile
   to apply to the reference type, represented as identifiers.

   We return an ADDR_EXPR whose "contents" are TARGET
   and whose type is the modifier list.  */
   
tree
make_reference_declarator (type_quals, target)
     tree type_quals, target;
{
  if (target)
    {
      if (TREE_CODE (target) == ADDR_EXPR)
	{
	  error ("cannot declare references to references");
	  return target;
	}
      if (TREE_CODE (target) == INDIRECT_REF)
	{
	  error ("cannot declare pointers to references");
	  return target;
	}
      if (TREE_CODE (target) == IDENTIFIER_NODE && ANON_AGGRNAME_P (target))
	  error ("type name expected before `&'");
    }
  target = build_parse_node (ADDR_EXPR, target);
  TREE_TYPE (target) = type_quals;
  return target;
}

/* Build names and nodes for overloaded operators.  */

tree ansi_opname[LAST_CPLUS_TREE_CODE];
tree ansi_assopname[LAST_CPLUS_TREE_CODE];

char *
operator_name_string (name)
     tree name;
{
  char *opname = IDENTIFIER_POINTER (name) + 2;
  tree *opname_table;
  int i, assign;

  /* Works for builtin and user defined types.  */
  if (IDENTIFIER_GLOBAL_VALUE (name)
      && TREE_CODE (IDENTIFIER_GLOBAL_VALUE (name)) == TYPE_DECL)
    return IDENTIFIER_POINTER (name);

  if (opname[0] == 'a' && opname[2] != '\0' && opname[2] != '_')
    {
      opname += 1;
      assign = 1;
      opname_table = ansi_assopname;
    }
  else
    {
      assign = 0;
      opname_table = ansi_opname;
    }

  for (i = 0; i < (int) LAST_CPLUS_TREE_CODE; i++)
    {
      if (opname[0] == IDENTIFIER_POINTER (opname_table[i])[2+assign]
	  && opname[1] == IDENTIFIER_POINTER (opname_table[i])[3+assign])
	break;
    }

  if (i == LAST_CPLUS_TREE_CODE)
    return "<invalid operator>";

  if (assign)
    return assignop_tab[i];
  else
    return opname_tab[i];
}

int interface_only;		/* whether or not current file is only for
				   interface definitions.  */
int interface_unknown;		/* whether or not we know this class
				   to behave according to #pragma interface.  */

/* lexical analyzer */

/* File used for outputting assembler code.  */
extern FILE *asm_out_file;

#ifndef WCHAR_TYPE_SIZE
#ifdef INT_TYPE_SIZE
#define WCHAR_TYPE_SIZE INT_TYPE_SIZE
#else
#define WCHAR_TYPE_SIZE	BITS_PER_WORD
#endif
#endif

/* Number of bytes in a wide character.  */
#define WCHAR_BYTES (WCHAR_TYPE_SIZE / BITS_PER_UNIT)

static int maxtoken;		/* Current nominal length of token buffer.  */
char *token_buffer;		/* Pointer to token buffer.
				   Actual allocated length is maxtoken + 2.  */

#include "hash.h"

int check_newline ();

/* Nonzero tells yylex to ignore \ in string constants.  */
static int ignore_escape_flag = 0;

static int skip_white_space ();

static tree
get_time_identifier (name)
     char *name;
{
  tree time_identifier;
  int len = strlen (name);
  char *buf = (char *) alloca (len + 6);
  strcpy (buf, "file ");
  bcopy (name, buf+5, len);
  buf[len+5] = '\0';
  time_identifier = get_identifier (buf);
  if (IDENTIFIER_LOCAL_VALUE (time_identifier) == NULL_TREE)
    {
      push_obstacks_nochange ();
      end_temporary_allocation ();
      IDENTIFIER_LOCAL_VALUE (time_identifier) = build_int_2 (0, 0);
      IDENTIFIER_CLASS_VALUE (time_identifier) = build_int_2 (0, 1);
      IDENTIFIER_GLOBAL_VALUE (time_identifier) = filename_times;
      filename_times = time_identifier;
      pop_obstacks ();
    }
  return time_identifier;
}

#ifdef __GNUC__
__inline
#endif
static int
my_get_run_time ()
{
  int old_quiet_flag = quiet_flag;
  int this_time;
  quiet_flag = 0;
  this_time = get_run_time ();
  quiet_flag = old_quiet_flag;
  return this_time;
}

/* Table indexed by tree code giving a string containing a character
   classifying the tree code.  Possibilities are
   t, d, s, c, r, <, 1 and 2.  See cp/tree.def for details.  */

#define DEFTREECODE(SYM, NAME, TYPE, LENGTH) TYPE,

char *cplus_tree_code_type[] = {
  "x",
#include "tree.def"
};
#undef DEFTREECODE

/* Table indexed by tree code giving number of expression
   operands beyond the fixed part of the node structure.
   Not used for types or decls.  */

#define DEFTREECODE(SYM, NAME, TYPE, LENGTH) LENGTH,

int cplus_tree_code_length[] = {
  0,
#include "tree.def"
};
#undef DEFTREECODE

/* Names of tree components.
   Used for printing out the tree and error messages.  */
#define DEFTREECODE(SYM, NAME, TYPE, LEN) NAME,

char *cplus_tree_code_name[] = {
  "@@dummy",
#include "tree.def"
};
#undef DEFTREECODE

/* toplev.c needs to call these.  */

void
lang_init ()
{
  /* the beginning of the file is a new line; check for # */
  /* With luck, we discover the real source file's name from that
     and put it in input_filename.  */
  put_back (check_newline ());

  if (flag_cadillac)
    cadillac_start ();
  if (flag_gnu_xref) GNU_xref_begin (input_filename);
  init_repo (input_filename);
}

void
lang_finish ()
{
  extern int errorcount, sorrycount;
  if (flag_gnu_xref) GNU_xref_end (errorcount+sorrycount);
}

char *
lang_identify ()
{
  return "cplusplus";
}

void
init_filename_times ()
{
  this_filename_time = get_time_identifier ("<top level>");
  if (flag_detailed_statistics)
    {
      header_time = 0;
      body_time = my_get_run_time ();
      TREE_INT_CST_LOW (IDENTIFIER_LOCAL_VALUE (this_filename_time)) = body_time;
    }
}

/* Change by Bryan Boreham, Kewill, Thu Jul 27 09:46:05 1989.
   Stuck this hack in to get the files open correctly; this is called
   in place of init_lex if we are an unexec'd binary.    */
void
reinit_lang_specific ()
{
  init_filename_times ();
  reinit_search_statistics ();
}

void
init_lex ()
{
  extern char *(*decl_printable_name) ();
  extern int flag_no_gnu_keywords;
  extern int flag_operator_names;

  int i;

  /* Initialize the lookahead machinery.  */
  init_spew ();

  /* Make identifier nodes long enough for the language-specific slots.  */
  set_identifier_size (sizeof (struct lang_identifier));
  decl_printable_name = lang_printable_name;

  init_cplus_expand ();

  tree_code_type
    = (char **) realloc (tree_code_type,
			 sizeof (char *) * LAST_CPLUS_TREE_CODE);
  tree_code_length
    = (int *) realloc (tree_code_length,
		       sizeof (int) * LAST_CPLUS_TREE_CODE);
  tree_code_name
    = (char **) realloc (tree_code_name,
			 sizeof (char *) * LAST_CPLUS_TREE_CODE);
  bcopy ((char *)cplus_tree_code_type,
	 (char *)(tree_code_type + (int) LAST_AND_UNUSED_TREE_CODE),
	 (LAST_CPLUS_TREE_CODE - (int)LAST_AND_UNUSED_TREE_CODE) * sizeof (char *));
  bcopy ((char *)cplus_tree_code_length,
	 (char *)(tree_code_length + (int) LAST_AND_UNUSED_TREE_CODE),
	 (LAST_CPLUS_TREE_CODE - (int)LAST_AND_UNUSED_TREE_CODE) * sizeof (int));
  bcopy ((char *)cplus_tree_code_name,