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cexp.y
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1994-02-06
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/* Parse C expressions for CCCP.
Copyright (C) 1987, 1992 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, 675 Mass Ave, Cambridge, MA 02139, 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
#ifndef NULL_PTR
#define NULL_PTR ((GENERIC_PTR)0)
#endif
int yylex ();
void yyerror ();
int expression_value;
static jmp_buf parse_return_error;
/* Nonzero means count most punctuation as part of a name. */
static int keyword_parsing = 0;
/* 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
/* 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;
int voidval;
char *sval;
}
%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)
{
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 (($$.value & $1.value & $3.value) < 0)
integer_overflow ();
} }
| exp '%' exp
{ if ($3.value == 0)
{
error ("division by zero in #if");
$3.value = 1;
}
$$.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;
$$.unsignedp = $1.unsignedp || $3.unsignedp; }
| exp AND exp
{ $$.value = ($1.value && $3.value);
$$.unsignedp = 0; }
| exp OR exp
{ $$.value = ($1.value || $3.value);
$$.unsignedp = 0; }
| exp '?' exp ':' exp
{ $$.value = $1.value ? $3.value : $5.value;
$$.unsignedp = $3.unsignedp || $5.unsignedp; }
| INT
{ $$ = 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