FSF GCC version 2.7.2

1 files changed, 1047 insertions, 0 deletions

diff --git a/gnu/usr.bin/gcc/cexp.y b/gnu/usr.bin/gcc/cexp.y
new file mode 100644
index 00000000000..d83de803364
--- /dev/null
+++ b/gnu/usr.bin/gcc/cexp.y
@@ -0,0 +1,1047 @@
+/* Parse C expressions for CCCP.
+   Copyright (C) 1987, 1992, 1994, 1995 Free Software Foundation.
+
+This program 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.
+
+This program 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 this program; if not, write to the Free Software
+Foundation, 59 Temple Place - Suite 330,
+Boston, MA 02111-1307, USA.
+
+ In other words, you are welcome to use, share and improve this program.
+ You are forbidden to forbid anyone else to use, share and improve
+ what you give them.   Help stamp out software-hoarding!
+
+ Adapted from expread.y of GDB by Paul Rubin, July 1986.  */
+
+/* Parse a C expression from text in a string  */
+   
+%{
+#include "config.h"
+#include <setjmp.h>
+/* #define YYDEBUG 1 */
+
+#ifdef MULTIBYTE_CHARS
+#include <stdlib.h>
+#include <locale.h>
+#endif
+
+#include <stdio.h>
+
+typedef unsigned char U_CHAR;
+
+/* This is used for communicating lists of keywords with cccp.c.  */
+struct arglist {
+  struct arglist *next;
+  U_CHAR *name;
+  int length;
+  int argno;
+};
+
+/* 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
+
+/* Find the largest host integer type and set its size and type.  */
+
+#ifndef HOST_BITS_PER_WIDE_INT
+
+#if HOST_BITS_PER_LONG > HOST_BITS_PER_INT
+#define HOST_BITS_PER_WIDE_INT HOST_BITS_PER_LONG
+#define HOST_WIDE_INT long
+#else
+#define HOST_BITS_PER_WIDE_INT HOST_BITS_PER_INT
+#define HOST_WIDE_INT int
+#endif
+
+#endif
+
+#ifndef NULL_PTR
+#define NULL_PTR ((GENERIC_PTR)0)
+#endif
+
+int yylex ();
+void yyerror ();
+HOST_WIDE_INT expression_value;
+
+static jmp_buf parse_return_error;
+
+/* Nonzero means count most punctuation as part of a name.  */
+static int keyword_parsing = 0;
+
+/* Nonzero means do not evaluate this expression.
+   This is a count, since unevaluated expressions can nest.  */
+static int skip_evaluation;
+
+/* some external tables of character types */
+extern unsigned char is_idstart[], is_idchar[], is_hor_space[];
+
+extern char *xmalloc ();
+
+/* Flag for -pedantic.  */
+extern int pedantic;
+
+/* Flag for -traditional.  */
+extern int traditional;
+
+#ifndef CHAR_TYPE_SIZE
+#define CHAR_TYPE_SIZE BITS_PER_UNIT
+#endif
+
+#ifndef INT_TYPE_SIZE
+#define INT_TYPE_SIZE BITS_PER_WORD
+#endif
+
+#ifndef LONG_TYPE_SIZE
+#define LONG_TYPE_SIZE BITS_PER_WORD
+#endif
+
+#ifndef WCHAR_TYPE_SIZE
+#define WCHAR_TYPE_SIZE INT_TYPE_SIZE
+#endif
+
+#ifndef MAX_CHAR_TYPE_SIZE
+#define MAX_CHAR_TYPE_SIZE CHAR_TYPE_SIZE
+#endif
+
+#ifndef MAX_INT_TYPE_SIZE
+#define MAX_INT_TYPE_SIZE INT_TYPE_SIZE
+#endif
+
+#ifndef MAX_LONG_TYPE_SIZE
+#define MAX_LONG_TYPE_SIZE LONG_TYPE_SIZE
+#endif
+
+#ifndef MAX_WCHAR_TYPE_SIZE
+#define MAX_WCHAR_TYPE_SIZE WCHAR_TYPE_SIZE
+#endif
+
+/* Yield nonzero if adding two numbers with A's and B's signs can yield a
+   number with SUM's sign, where A, B, and SUM are all C integers.  */
+#define possible_sum_sign(a, b, sum) ((((a) ^ (b)) | ~ ((a) ^ (sum))) < 0)
+
+static void integer_overflow ();
+static long left_shift ();
+static long right_shift ();
+%}
+
+%union {
+  struct constant {long value; int unsignedp;} integer;
+  struct name {U_CHAR *address; int length;} name;
+  struct arglist *keywords;
+}
+
+%type <integer> exp exp1 start
+%type <keywords> keywords
+%token <integer> INT CHAR
+%token <name> NAME
+%token <integer> ERROR
+
+%right '?' ':'
+%left ','
+%left OR
+%left AND
+%left '|'
+%left '^'
+%left '&'
+%left EQUAL NOTEQUAL
+%left '<' '>' LEQ GEQ
+%left LSH RSH
+%left '+' '-'
+%left '*' '/' '%'
+%right UNARY
+
+/* %expect 40 */
+
+%%
+
+start   :	exp1
+		{ expression_value = $1.value; }
+	;
+
+/* Expressions, including the comma operator.  */
+exp1	:	exp
+	|	exp1 ',' exp
+			{ if (pedantic)
+			    pedwarn ("comma operator in operand of `#if'");
+			  $$ = $3; }
+	;
+
+/* Expressions, not including the comma operator.  */
+exp	:	'-' exp    %prec UNARY
+			{ $$.value = - $2.value;
+			  if (($$.value & $2.value) < 0 && ! $2.unsignedp)
+			    integer_overflow ();
+			  $$.unsignedp = $2.unsignedp; }
+	|	'!' exp    %prec UNARY
+			{ $$.value = ! $2.value;
+			  $$.unsignedp = 0; }
+	|	'+' exp    %prec UNARY
+			{ $$ = $2; }
+	|	'~' exp    %prec UNARY
+			{ $$.value = ~ $2.value;
+			  $$.unsignedp = $2.unsignedp; }
+	|	'#' NAME
+  			{ $$.value = check_assertion ($2.address, $2.length,
+						      0, NULL_PTR);
+			  $$.unsignedp = 0; }
+	|	'#' NAME
+			{ keyword_parsing = 1; }
+		'(' keywords ')'
+  			{ $$.value = check_assertion ($2.address, $2.length,
+						      1, $5);
+			  keyword_parsing = 0;
+			  $$.unsignedp = 0; }
+	|	'(' exp1 ')'
+			{ $$ = $2; }
+	;
+
+/* Binary operators in order of decreasing precedence.  */
+exp	:	exp '*' exp
+			{ $$.unsignedp = $1.unsignedp || $3.unsignedp;
+			  if ($$.unsignedp)
+			    $$.value = (unsigned long) $1.value * $3.value;
+			  else
+			    {
+			      $$.value = $1.value * $3.value;
+			      if ($1.value
+				  && ($$.value / $1.value != $3.value
+				      || ($$.value & $1.value & $3.value) < 0))
+				integer_overflow ();
+			    } }
+	|	exp '/' exp
+			{ if ($3.value == 0)
+			    {
+			      if (!skip_evaluation)
+				error ("division by zero in #if");
+			      $3.value = 1;
+			    }
+			  $$.unsignedp = $1.unsignedp || $3.unsignedp;
+			  if ($$.unsignedp)
+			    $$.value = (unsigned long) $1.value / $3.value;
+			  else
+			    {
+			      $$.value = $1.value / $3.value;
+			      if (($$.value & $1.value & $3.value) < 0)
+				integer_overflow ();
+			    } }
+	|	exp '%' exp
+			{ if ($3.value == 0)
+			    {
+			      if (!skip_evaluation)
+				error ("division by zero in #if");
+			      $3.value = 1;
+			    }
+			  $$.unsignedp = $1.unsignedp || $3.unsignedp;
+			  if ($$.unsignedp)
+			    $$.value = (unsigned long) $1.value % $3.value;
+			  else
+			    $$.value = $1.value % $3.value; }
+	|	exp '+' exp
+			{ $$.value = $1.value + $3.value;
+			  $$.unsignedp = $1.unsignedp || $3.unsignedp;
+			  if (! $$.unsignedp
+			      && ! possible_sum_sign ($1.value, $3.value,
+						      $$.value))
+			    integer_overflow (); }
+	|	exp '-' exp
+			{ $$.value = $1.value - $3.value;
+			  $$.unsignedp = $1.unsignedp || $3.unsignedp;
+			  if (! $$.unsignedp
+			      && ! possible_sum_sign ($$.value, $3.value,
+						      $1.value))
+			    integer_overflow (); }
+	|	exp LSH exp
+			{ $$.unsignedp = $1.unsignedp;
+			  if ($3.value < 0 && ! $3.unsignedp)
+			    $$.value = right_shift (&$1, -$3.value);
+			  else
+			    $$.value = left_shift (&$1, $3.value); }
+	|	exp RSH exp
+			{ $$.unsignedp = $1.unsignedp;
+			  if ($3.value < 0 && ! $3.unsignedp)
+			    $$.value = left_shift (&$1, -$3.value);
+			  else
+			    $$.value = right_shift (&$1, $3.value); }
+	|	exp EQUAL exp
+			{ $$.value = ($1.value == $3.value);
+			  $$.unsignedp = 0; }
+	|	exp NOTEQUAL exp
+			{ $$.value = ($1.value != $3.value);
+			  $$.unsignedp = 0; }
+	|	exp LEQ exp
+			{ $$.unsignedp = 0;
+			  if ($1.unsignedp || $3.unsignedp)
+			    $$.value = (unsigned long) $1.value <= $3.value;
+			  else
+			    $$.value = $1.value <= $3.value; }
+	|	exp GEQ exp
+			{ $$.unsignedp = 0;
+			  if ($1.unsignedp || $3.unsignedp)
+			    $$.value = (unsigned long) $1.value >= $3.value;
+			  else
+			    $$.value = $1.value >= $3.value; }
+	|	exp '<' exp
+			{ $$.unsignedp = 0;
+			  if ($1.unsignedp || $3.unsignedp)
+			    $$.value = (unsigned long) $1.value < $3.value;
+			  else
+			    $$.value = $1.value < $3.value; }
+	|	exp '>' exp
+			{ $$.unsignedp = 0;
+			  if ($1.unsignedp || $3.unsignedp)
+			    $$.value = (unsigned long) $1.value > $3.value;
+			  else
+			    $$.value = $1.value > $3.value; }
+	|	exp '&' exp
+			{ $$.value = $1.value & $3.value;
+			  $$.unsignedp = $1.unsignedp || $3.unsignedp; }
+	|	exp '^' exp
+			{ $$.value = $1.value ^ $3.value;
+			  $$.unsignedp = $1.unsignedp || $3.unsignedp; }
+	|	exp '|' exp
+			{ $$.value = $1.value | $3.value;
+			  $$.unsignedp = $1.unsignedp || $3.unsignedp; }
+	|	exp AND
+			{ skip_evaluation += !$1.value; }
+		exp
+			{ skip_evaluation -= !$1.value;
+			  $$.value = ($1.value && $4.value);
+			  $$.unsignedp = 0; }
+	|	exp OR
+			{ skip_evaluation += !!$1.value; }
+		exp
+			{ skip_evaluation -= !!$1.value;
+			  $$.value = ($1.value || $4.value);
+			  $$.unsignedp = 0; }
+	|	exp '?'
+			{ skip_evaluation += !$1.value; }
+	        exp ':'
+			{ skip_evaluation += !!$1.value - !$1.value; }
+		exp
+			{ skip_evaluation -= !!$1.value;
+			  $$.value = $1.value ? $4.value : $7.value;
+			  $$.unsignedp = $4.unsignedp || $7.unsignedp; }
+	|	INT
+			{ $$ = yylval.integer; }
+	|	CHAR
+			{ $$ = yylval.integer; }
+	|	NAME
+			{ $$.value = 0;
+			  $$.unsignedp = 0; }
+	;
+
+keywords :
+			{ $$ = 0; } 
+	|	'(' keywords ')' keywords
+			{ struct arglist *temp;
+			  $$ = (struct arglist *) xmalloc (sizeof (struct arglist));
+			  $$->next = $2;
+			  $$->name = (U_CHAR *) "(";
+			  $$->length = 1;
+			  temp = $$;
+			  while (temp != 0 && temp->next != 0)
+			    temp = temp->next;
+			  temp->next = (struct arglist *) xmalloc (sizeof (struct arglist));
+			  temp->next->next = $4;
+			  temp->next->name = (U_CHAR *) ")";
+			  temp->next->length = 1; }
+	|	NAME keywords
+			{ $$ = (struct arglist *) xmalloc (sizeof (struct arglist));
+			  $$->name = $1.address;
+			  $$->length = $1.length;
+			  $$->next = $2; } 
+	;
+%%
+
+/* During parsing of a C expression, the pointer to the next character
+   is in this variable.  */
+
+static char *lexptr;
+
+/* Take care of parsing a number (anything that starts with a digit).
+   Set yylval and return the token type; update lexptr.
+   LEN is the number of characters in it.  */
+
+/* maybe needs to actually deal with floating point numbers */
+
+int
+parse_number (olen)
+     int olen;
+{
+  register char *p = lexptr;
+  register int c;
+  register unsigned long n = 0, nd, ULONG_MAX_over_base;
+  register int base = 10;
+  register int len = olen;
+  register int overflow = 0;
+  register int digit, largest_digit = 0;
+  int spec_long = 0;
+
+  for (c = 0; c < len; c++)
+    if (p[c] == '.') {
+      /* It's a float since it contains a point.  */
+      yyerror ("floating point numbers not allowed in #if expressions");
+      return ERROR;
+    }
+
+  yylval.integer.unsignedp = 0;
+
+  if (len >= 3 && (!strncmp (p, "0x", 2) || !strncmp (p, "0X", 2))) {
+    p += 2;
+    base = 16;
+    len -= 2;
+  }
+  else if (*p == '0')
+    base = 8;
+
+  ULONG_MAX_over_base = (unsigned long) -1 / base;
+
+  for (; len > 0; len--) {
+    c = *p++;
+
+    if (c >= '0' && c <= '9')
+      digit = c - '0';
+    else if (base == 16 && c >= 'a' && c <= 'f')
+      digit = c - 'a' + 10;
+    else if (base == 16 && c >= 'A' && c <= 'F')
+      digit = c - 'A' + 10;
+    else {
+      /* `l' means long, and `u' means unsigned.  */
+      while (1) {
+	if (c == 'l' || c == 'L')
+	  {
+	    if (spec_long)
+	      yyerror ("two `l's in integer constant");
+	    spec_long = 1;
+	  }
+	else if (c == 'u' || c == 'U')
+	  {
+	    if (yylval.integer.unsignedp)
+	      yyerror ("two `u's in integer constant");
+	    yylval.integer.unsignedp = 1;
+	  }
+	else
+	  break;
+
+	if (--len == 0)
+	  break;
+	c = *p++;
+      }
+      /* Don't look for any more digits after the suffixes.  */
+      break;
+    }
+    if (largest_digit < digit)
+      largest_digit = digit;
+    nd = n * base + digit;
+    overflow |= ULONG_MAX_over_base < n | nd < n;
+    n = nd;
+  }
+
+  if (len != 0) {
+    yyerror ("Invalid number in #if expression");
+    return ERROR;
+  }
+
+  if (base <= largest_digit)
+    warning ("integer constant contains digits beyond the radix");
+
+  if (overflow)
+    warning ("integer constant out of range");
+
+  /* If too big to be signed, consider it unsigned.  */
+  if ((long) n < 0 && ! yylval.integer.unsignedp)
+    {
+      if (base == 10)
+	warning ("integer constant is so large that it is unsigned");
+      yylval.integer.unsignedp = 1;
+    }
+
+  lexptr = p;
+  yylval.integer.value = n;
+  return INT;
+}
+
+struct token {
+  char *operator;
+  int token;
+};
+
+static struct token tokentab2[] = {
+  {"&&", AND},
+  {"||", OR},
+  {"<<", LSH},
+  {">>", RSH},
+  {"==", EQUAL},
+  {"!=", NOTEQUAL},
+  {"<=", LEQ},
+  {">=", GEQ},
+  {"++", ERROR},
+  {"--", ERROR},
+  {NULL, ERROR}
+};
+
+/* Read one token, getting characters through lexptr.  */
+
+int
+yylex ()
+{
+  register int c;
+  register int namelen;
+  register unsigned char *tokstart;
+  register struct token *toktab;
+  int wide_flag;
+
+ retry:
+
+  tokstart = (unsigned char *) lexptr;
+  c = *tokstart;
+  /* See if it is a special token of length 2.  */
+  if (! keyword_parsing)
+    for (toktab = tokentab2; toktab->operator != NULL; toktab++)
+      if (c == *toktab->operator && tokstart[1] == toktab->operator[1]) {
+	lexptr += 2;
+	if (toktab->token == ERROR)
+	  {
+	    char *buf = (char *) alloca (40);
+	    sprintf (buf, "`%s' not allowed in operand of `#if'", toktab->operator);
+	    yyerror (buf);
+	  }
+	return toktab->token;
+      }
+
+  switch (c) {
+  case 0:
+    return 0;
+    
+  case ' ':
+  case '\t':
+  case '\r':
+  case '\n':
+    lexptr++;
+    goto retry;
+    
+  case 'L':
+    /* Capital L may start a wide-string or wide-character constant.  */
+    if (lexptr[1] == '\'')
+      {
+	lexptr++;
+	wide_flag = 1;
+	goto char_constant;
+      }
+    if (lexptr[1] == '"')
+      {
+	lexptr++;
+	wide_flag = 1;
+	goto string_constant;
+      }
+    break;
+
+  case '\'':
+    wide_flag = 0;
+  char_constant:
+    lexptr++;
+    if (keyword_parsing) {
+      char *start_ptr = lexptr - 1;
+      while (1) {
+	c = *lexptr++;
+	if (c == '\\')
+	  c = parse_escape (&lexptr);
+	else if (c == '\'')
+	  break;
+      }
+      yylval.name.address = tokstart;
+      yylval.name.length = lexptr - start_ptr;
+      return NAME;
+    }
+
+    /* This code for reading a character constant
+       handles multicharacter constants and wide characters.
+       It is mostly copied from c-lex.c.  */
+    {
+      register int result = 0;
+      register num_chars = 0;
+      unsigned width = MAX_CHAR_TYPE_SIZE;
+      int max_chars;
+      char *token_buffer;
+
+      if (wide_flag)
+	{
+	  width = MAX_WCHAR_TYPE_SIZE;
+#ifdef MULTIBYTE_CHARS
+	  max_chars = MB_CUR_MAX;
+#else
+	  max_chars = 1;
+#endif
+	}
+      else
+	max_chars = MAX_LONG_TYPE_SIZE / width;
+
+      token_buffer = (char *) alloca (max_chars + 1);
+
+      while (1)
+	{
+	  c = *lexptr++;
+
+	  if (c == '\'' || c == EOF)
+	    break;
+
+	  if (c == '\\')
+	    {
+	      c = parse_escape (&lexptr);
+	      if (width < HOST_BITS_PER_INT
+		  && (unsigned) c >= (1 << width))
+		pedwarn ("escape sequence out of range for character");
+	    }
+
+	  num_chars++;
+
+	  /* Merge character into result; ignore excess chars.  */
+	  if (num_chars < max_chars + 1)
+	    {
+	      if (width < HOST_BITS_PER_INT)
+		result = (result << width) | (c & ((1 << width) - 1));
+	      else
+		result = c;
+	      token_buffer[num_chars - 1] = c;
+	    }
+	}
+
+      token_buffer[num_chars] = 0;
+
+      if (c != '\'')
+	error ("malformatted character constant");
+      else if (num_chars == 0)
+	error ("empty character constant");
+      else if (num_chars > max_chars)
+	{
+	  num_chars = max_chars;
+	  error ("character constant too long");
+	}
+      else if (num_chars != 1 && ! traditional)
+	warning ("multi-character character constant");
+
+      /* If char type is signed, sign-extend the constant.  */
+      if (! wide_flag)
+	{
+	  int num_bits = num_chars * width;
+
+	  if (lookup ("__CHAR_UNSIGNED__", sizeof ("__CHAR_UNSIGNED__")-1, -1)
+	      || ((result >> (num_bits - 1)) & 1) == 0)
+	    yylval.integer.value
+	      = result & ((unsigned long) ~0 >> (HOST_BITS_PER_LONG - num_bits));
+	  else
+	    yylval.integer.value
+	      = result | ~((unsigned long) ~0 >> (HOST_BITS_PER_LONG - num_bits));
+	}
+      else
+	{
+#ifdef MULTIBYTE_CHARS
+	  /* Set the initial shift state and convert the next sequence.  */
+	  result = 0;
+	  /* In all locales L'\0' is zero and mbtowc will return zero,
+	     so don't use it.  */
+	  if (num_chars > 1
+	      || (num_chars == 1 && token_buffer[0] != '\0'))
+	    {
+	      wchar_t wc;
+	      (void) mbtowc (NULL_PTR, NULL_PTR, 0);
+	      if (mbtowc (& wc, token_buffer, num_chars) == num_chars)
+		result = wc;
+	      else
+		warning ("Ignoring invalid multibyte character");
+	    }
+#endif
+	  yylval.integer.value = result;
+	}
+    }
+
+    /* This is always a signed type.  */
+    yylval.integer.unsignedp = 0;
+    
+    return CHAR;
+
+    /* some of these chars are invalid in constant expressions;
+       maybe do something about them later */
+  case '/':
+  case '+':
+  case '-':
+  case '*':
+  case '%':
+  case '|':
+  case '&':
+  case '^':
+  case '~':
+  case '!':
+  case '@':
+  case '<':
+  case '>':
+  case '[':
+  case ']':
+  case '.':
+  case '?':
+  case ':':
+  case '=':
+  case '{':
+  case '}':
+  case ',':
+  case '#':
+    if (keyword_parsing)
+      break;
+  case '(':
+  case ')':
+    lexptr++;
+    return c;
+
+  case '"':
+  string_constant:
+    if (keyword_parsing) {
+      char *start_ptr = lexptr;
+      lexptr++;
+      while (1) {
+	c = *lexptr++;
+	if (c == '\\')
+	  c = parse_escape (&lexptr);
+	else if (c == '"')
+	  break;
+      }
+      yylval.name.address = tokstart;
+      yylval.name.length = lexptr - start_ptr;
+      return NAME;
+    }
+    yyerror ("string constants not allowed in #if expressions");
+    return ERROR;
+  }
+
+  if (c >= '0' && c <= '9' && !keyword_parsing) {
+    /* It's a number */
+    for (namelen = 0;
+	 c = tokstart[namelen], is_idchar[c] || c == '.'; 
+	 namelen++)
+      ;
+    return parse_number (namelen);
+  }
+
+  /* It is a name.  See how long it is.  */
+
+  if (keyword_parsing) {
+    for (namelen = 0;; namelen++) {
+      if (is_hor_space[tokstart[namelen]])
+	break;
+      if (tokstart[namelen] == '(' || tokstart[namelen] == ')')
+	break;
+      if (tokstart[namelen] == '"' || tokstart[namelen] == '\'')
+	break;
+    }
+  } else {
+    if (!is_idstart[c]) {
+      yyerror ("Invalid token in expression");
+      return ERROR;
+    }
+
+    for (namelen = 0; is_idchar[tokstart[namelen]]; namelen++)
+      ;
+  }
+  
+  lexptr += namelen;
+  yylval.name.address = tokstart;
+  yylval.name.length = namelen;
+  return NAME;
+}
+
+
+/* Parse a C escape sequence.  STRING_PTR points to a variable
+   containing a pointer to the string to parse.  That pointer
+   is updated past the characters we use.  The value of the
+   escape sequence is returned.
+
+   A negative value means the sequence \ newline was seen,
+   which is supposed to be equivalent to nothing at all.
+
+   If \ is followed by a null character, we return a negative
+   value and leave the string pointer pointing at the null character.
+
+   If \ is followed by 000, we return 0 and leave the string pointer
+   after the zeros.  A value of 0 does not mean end of string.  */
+
+int
+parse_escape (string_ptr)
+     char **string_ptr;
+{
+  register int c = *(*string_ptr)++;
+  switch (c)
+    {
+    case 'a':
+      return TARGET_BELL;
+    case 'b':
+      return TARGET_BS;
+    case 'e':
+    case 'E':
+      if (pedantic)
+	pedwarn ("non-ANSI-standard escape sequence, `\\%c'", c);
+      return 033;
+    case 'f':
+      return TARGET_FF;
+    case 'n':
+      return TARGET_NEWLINE;
+    case 'r':
+      return TARGET_CR;
+    case 't':
+      return TARGET_TAB;
+    case 'v':
+      return TARGET_VT;
+    case '\n':
+      return -2;
+    case 0:
+      (*string_ptr)--;
+      return 0;
+      
+    case '0':
+    case '1':
+    case '2':
+    case '3':
+    case '4':
+    case '5':
+    case '6':
+    case '7':
+      {
+	register int i = c - '0';
+	register int count = 0;
+	while (++count < 3)
+	  {
+	    c = *(*string_ptr)++;
+	    if (c >= '0' && c <= '7')
+	      i = (i << 3) + c - '0';
+	    else
+	      {
+		(*string_ptr)--;
+		break;
+	      }
+	  }
+	if ((i & ~((1 << MAX_CHAR_TYPE_SIZE) - 1)) != 0)
+	  {
+	    i &= (1 << MAX_CHAR_TYPE_SIZE) - 1;
+	    warning ("octal character constant does not fit in a byte");
+	  }
+	return i;
+      }
+    case 'x':
+      {
+	register unsigned i = 0, overflow = 0, digits_found = 0, digit;
+	for (;;)
+	  {
+	    c = *(*string_ptr)++;
+	    if (c >= '0' && c <= '9')
+	      digit = c - '0';
+	    else if (c >= 'a' && c <= 'f')
+	      digit = c - 'a' + 10;
+	    else if (c >= 'A' && c <= 'F')
+	      digit = c - 'A' + 10;
+	    else
+	      {
+		(*string_ptr)--;
+		break;
+	      }
+	    overflow |= i ^ (i << 4 >> 4);
+	    i = (i << 4) + digit;
+	    digits_found = 1;
+	  }
+	if (!digits_found)
+	  yyerror ("\\x used with no following hex digits");
+	if (overflow | (i & ~((1 << BITS_PER_UNIT) - 1)))
+	  {
+	    i &= (1 << BITS_PER_UNIT) - 1;
+	    warning ("hex character constant does not fit in a byte");
+	  }
+	return i;
+      }
+    default:
+      return c;
+    }
+}
+
+void
+yyerror (s)
+     char *s;
+{
+  error (s);
+  skip_evaluation = 0;
+  longjmp (parse_return_error, 1);
+}
+
+static void
+integer_overflow ()
+{
+  if (!skip_evaluation && pedantic)
+    pedwarn ("integer overflow in preprocessor expression");
+}
+
+static long
+left_shift (a, b)
+     struct constant *a;
+     unsigned long b;
+{
+   /* It's unclear from the C standard whether shifts can overflow.
+      The following code ignores overflow; perhaps a C standard
+      interpretation ruling is needed.  */
+  if (b >= HOST_BITS_PER_LONG)
+    return 0;
+  else if (a->unsignedp)
+    return (unsigned long) a->value << b;
+  else
+    return a->value << b;
+}
+
+static long
+right_shift (a, b)
+     struct constant *a;
+     unsigned long b;
+{
+  if (b >= HOST_BITS_PER_LONG)
+    return a->unsignedp ? 0 : a->value >> (HOST_BITS_PER_LONG - 1);
+  else if (a->unsignedp)
+    return (unsigned long) a->value >> b;
+  else
+    return a->value >> b;
+}
+
+/* This page contains the entry point to this file.  */
+
+/* Parse STRING as an expression, and complain if this fails
+   to use up all of the contents of STRING.  */
+/* We do not support C comments.  They should be removed before
+   this function is called.  */
+
+HOST_WIDE_INT
+parse_c_expression (string)
+     char *string;
+{
+  lexptr = string;
+  
+  if (lexptr == 0 || *lexptr == 0) {
+    error ("empty #if expression");
+    return 0;			/* don't include the #if group */
+  }
+
+  /* if there is some sort of scanning error, just return 0 and assume
+     the parsing routine has printed an error message somewhere.
+     there is surely a better thing to do than this.     */
+  if (setjmp (parse_return_error))
+    return 0;
+
+  if (yyparse ())
+    return 0;			/* actually this is never reached
+				   the way things stand. */
+  if (*lexptr)
+    error ("Junk after end of expression.");
+
+  return expression_value;	/* set by yyparse () */
+}
+
+#ifdef TEST_EXP_READER
+extern int yydebug;
+
+/* Main program for testing purposes.  */
+int
+main ()
+{
+  int n, c;
+  char buf[1024];
+
+/*
+  yydebug = 1;
+*/
+  initialize_random_junk ();
+
+  for (;;) {
+    printf ("enter expression: ");
+    n = 0;
+    while ((buf[n] = getchar ()) != '\n' && buf[n] != EOF)
+      n++;
+    if (buf[n] == EOF)
+      break;
+    buf[n] = '\0';
+    printf ("parser returned %ld\n", parse_c_expression (buf));
+  }
+
+  return 0;
+}
+
+/* table to tell if char can be part of a C identifier. */
+unsigned char is_idchar[256];
+/* table to tell if char can be first char of a c identifier. */
+unsigned char is_idstart[256];
+/* table to tell if c is horizontal space.  isspace () thinks that
+   newline is space; this is not a good idea for this program. */
+char is_hor_space[256];
+
+/*
+ * initialize random junk in the hash table and maybe other places
+ */
+initialize_random_junk ()
+{
+  register int i;
+
+  /*
+   * Set up is_idchar and is_idstart tables.  These should be
+   * faster than saying (is_alpha (c) || c == '_'), etc.
+   * Must do set up these things before calling any routines tthat
+   * refer to them.
+   */
+  for (i = 'a'; i <= 'z'; i++) {
+    ++is_idchar[i - 'a' + 'A'];
+    ++is_idchar[i];
+    ++is_idstart[i - 'a' + 'A'];
+    ++is_idstart[i];
+  }
+  for (i = '0'; i <= '9'; i++)
+    ++is_idchar[i];
+  ++is_idchar['_'];
+  ++is_idstart['_'];
+#if DOLLARS_IN_IDENTIFIERS
+  ++is_idchar['$'];
+  ++is_idstart['$'];
+#endif
+
+  /* horizontal space table */
+  ++is_hor_space[' '];
+  ++is_hor_space['\t'];
+}
+
+error (msg)
+{
+  printf ("error: %s\n", msg);
+}
+
+warning (msg)
+{
+  printf ("warning: %s\n", msg);
+}
+
+struct hashnode *
+lookup (name, len, hash)
+     char *name;
+     int len;
+     int hash;
+{
+  return (DEFAULT_SIGNED_CHAR) ? 0 : ((struct hashnode *) -1);
+}
+#endif