mirror of
https://git.FreeBSD.org/src.git
synced 2024-12-27 11:55:06 +00:00
568 lines
13 KiB
Plaintext
568 lines
13 KiB
Plaintext
/* Parse C expressions for CCCP.
|
||
Copyright (C) 1987, 2000, 2001 Free Software Foundation.
|
||
Adapted from expread.y of GDB by Paul Rubin, July 1986.
|
||
Adapted to ANSI C, Richard Stallman, Jan 1987
|
||
Dusted off, polished, and adapted for use as traditional
|
||
preprocessor only, Zack Weinberg, Jul 2000
|
||
|
||
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. */
|
||
|
||
/* Parse a C expression from text in a string */
|
||
|
||
%{
|
||
#include "config.h"
|
||
#include "system.h"
|
||
#include "intl.h"
|
||
#include "tradcpp.h"
|
||
#include <setjmp.h>
|
||
|
||
static int yylex PARAMS ((void));
|
||
static void yyerror PARAMS ((const char *msgid)) ATTRIBUTE_NORETURN;
|
||
|
||
static int parse_number PARAMS ((int));
|
||
static int parse_escape PARAMS ((const char **));
|
||
|
||
static int expression_value;
|
||
static jmp_buf parse_return_error;
|
||
|
||
/* During parsing of a C expression, the pointer to the next
|
||
character is in this variable. */
|
||
|
||
static const char *lexptr;
|
||
%}
|
||
|
||
%union {
|
||
struct constant {long value; int unsignedp;} integer;
|
||
int voidval;
|
||
char *sval;
|
||
}
|
||
|
||
%type <integer> exp exp1 start
|
||
%token <integer> INT CHAR
|
||
%token <sval> 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
|
||
{ $$ = $3; }
|
||
;
|
||
|
||
/* Expressions, not including the comma operator. */
|
||
exp : '-' exp %prec UNARY
|
||
{ $$.value = - $2.value;
|
||
$$.unsignedp = $2.unsignedp; }
|
||
| '!' exp %prec UNARY
|
||
{ $$.value = ! $2.value;
|
||
$$.unsignedp = 0; }
|
||
| '+' exp %prec UNARY
|
||
{ $$ = $2; }
|
||
| '~' exp %prec UNARY
|
||
{ $$.value = ~ $2.value;
|
||
$$.unsignedp = $2.unsignedp; }
|
||
| '(' exp1 ')'
|
||
{ $$ = $2; }
|
||
;
|
||
|
||
/* Binary operators in order of decreasing precedence. */
|
||
exp : exp '*' exp
|
||
{ $$.unsignedp = $1.unsignedp || $3.unsignedp;
|
||
if ($$.unsignedp)
|
||
$$.value = (unsigned) $1.value * $3.value;
|
||
else
|
||
$$.value = $1.value * $3.value; }
|
||
| exp '/' exp
|
||
{ if ($3.value == 0)
|
||
{
|
||
error ("division by zero in #if");
|
||
$3.value = 1;
|
||
}
|
||
$$.unsignedp = $1.unsignedp || $3.unsignedp;
|
||
if ($$.unsignedp)
|
||
$$.value = (unsigned) $1.value / $3.value;
|
||
else
|
||
$$.value = $1.value / $3.value; }
|
||
| exp '%' exp
|
||
{ if ($3.value == 0)
|
||
{
|
||
error ("division by zero in #if");
|
||
$3.value = 1;
|
||
}
|
||
$$.unsignedp = $1.unsignedp || $3.unsignedp;
|
||
if ($$.unsignedp)
|
||
$$.value = (unsigned) $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;
|
||
$$.unsignedp = $1.unsignedp || $3.unsignedp; }
|
||
| exp LSH exp
|
||
{ $$.unsignedp = $1.unsignedp;
|
||
if ($$.unsignedp)
|
||
$$.value = (unsigned) $1.value << $3.value;
|
||
else
|
||
$$.value = $1.value << $3.value; }
|
||
| exp RSH exp
|
||
{ $$.unsignedp = $1.unsignedp;
|
||
if ($$.unsignedp)
|
||
$$.value = (unsigned) $1.value >> $3.value;
|
||
else
|
||
$$.value = $1.value >> $3.value; }
|
||
| exp EQUAL exp
|
||
{ $$.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)
|
||
$$.value =
|
||
(unsigned) $1.value <= (unsigned) $3.value;
|
||
else
|
||
$$.value = $1.value <= $3.value; }
|
||
| exp GEQ exp
|
||
{ $$.unsignedp = 0;
|
||
if ($1.unsignedp || $3.unsignedp)
|
||
$$.value =
|
||
(unsigned) $1.value >= (unsigned) $3.value;
|
||
else
|
||
$$.value = $1.value >= $3.value; }
|
||
| exp '<' exp
|
||
{ $$.unsignedp = 0;
|
||
if ($1.unsignedp || $3.unsignedp)
|
||
$$.value =
|
||
(unsigned) $1.value < (unsigned) $3.value;
|
||
else
|
||
$$.value = $1.value < $3.value; }
|
||
| exp '>' exp
|
||
{ $$.unsignedp = 0;
|
||
if ($1.unsignedp || $3.unsignedp)
|
||
$$.value =
|
||
(unsigned) $1.value > (unsigned) $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;
|
||
$$.unsignedp = 0; }
|
||
| '#' { $$.value =
|
||
test_assertion ((unsigned 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 */
|
||
|
||
static int
|
||
parse_number (olen)
|
||
int olen;
|
||
{
|
||
const char *p = lexptr;
|
||
long n = 0;
|
||
int c;
|
||
int base = 10;
|
||
int len = olen;
|
||
|
||
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;
|
||
}
|
||
|
||
/* Traditionally, all numbers are signed. However, we make it
|
||
unsigned if requested with a suffix. */
|
||
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;
|
||
|
||
while (len > 0) {
|
||
c = *p++;
|
||
len--;
|
||
if (ISUPPER (c))
|
||
c = TOLOWER (c);
|
||
|
||
if (ISDIGIT (c)
|
||
|| (base == 16 && ISXDIGIT (c))) {
|
||
n = (n * base) + hex_value (c);
|
||
} else {
|
||
/* `l' means long, and `u' means unsigned. */
|
||
while (1) {
|
||
if (c == 'l' || c == 'L')
|
||
;
|
||
else if (c == 'u' || c == 'U')
|
||
yylval.integer.unsignedp = 1;
|
||
else
|
||
break;
|
||
|
||
if (len == 0)
|
||
break;
|
||
c = *p++;
|
||
len--;
|
||
}
|
||
/* Don't look for any more digits after the suffixes. */
|
||
break;
|
||
}
|
||
}
|
||
|
||
if (len != 0) {
|
||
yyerror ("invalid number in #if expression");
|
||
return ERROR;
|
||
}
|
||
|
||
lexptr = p;
|
||
yylval.integer.value = n;
|
||
return INT;
|
||
}
|
||
|
||
struct token {
|
||
const char *const operator;
|
||
const int token;
|
||
};
|
||
|
||
#ifndef NULL
|
||
#define NULL 0
|
||
#endif
|
||
|
||
static const struct token tokentab2[] = {
|
||
{"&&", AND},
|
||
{"||", OR},
|
||
{"<<", LSH},
|
||
{">>", RSH},
|
||
{"==", EQUAL},
|
||
{"!=", NOTEQUAL},
|
||
{"<=", LEQ},
|
||
{">=", GEQ},
|
||
{NULL, ERROR}
|
||
};
|
||
|
||
/* Read one token, getting characters through lexptr. */
|
||
|
||
static int
|
||
yylex ()
|
||
{
|
||
int c;
|
||
int namelen;
|
||
const char *tokstart;
|
||
const struct token *toktab;
|
||
|
||
retry:
|
||
|
||
tokstart = lexptr;
|
||
c = *tokstart;
|
||
/* See if it is a special token of length 2. */
|
||
for (toktab = tokentab2; toktab->operator != NULL; toktab++)
|
||
if (c == *toktab->operator && tokstart[1] == toktab->operator[1]) {
|
||
lexptr += 2;
|
||
return toktab->token;
|
||
}
|
||
|
||
switch (c) {
|
||
case 0:
|
||
return 0;
|
||
|
||
case ' ':
|
||
case '\t':
|
||
case '\r':
|
||
case '\n':
|
||
lexptr++;
|
||
goto retry;
|
||
|
||
case '\'':
|
||
lexptr++;
|
||
c = *lexptr++;
|
||
if (c == '\\')
|
||
c = parse_escape (&lexptr);
|
||
|
||
/* Sign-extend the constant if chars are signed on target machine. */
|
||
{
|
||
if (flag_signed_char == 0
|
||
|| ((c >> (CHAR_TYPE_SIZE - 1)) & 1) == 0)
|
||
yylval.integer.value = c & ((1 << CHAR_TYPE_SIZE) - 1);
|
||
else
|
||
yylval.integer.value = c | ~((1 << CHAR_TYPE_SIZE) - 1);
|
||
}
|
||
|
||
yylval.integer.unsignedp = 0;
|
||
c = *lexptr++;
|
||
if (c != '\'') {
|
||
yyerror ("invalid character constant in #if");
|
||
return ERROR;
|
||
}
|
||
|
||
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 '}':
|
||
case ',':
|
||
case '#':
|
||
lexptr++;
|
||
return c;
|
||
|
||
case '"':
|
||
yyerror ("double quoted strings not allowed in #if expressions");
|
||
return ERROR;
|
||
}
|
||
if (ISDIGIT (c)) {
|
||
/* It's a number */
|
||
for (namelen = 0;
|
||
c = tokstart[namelen], is_idchar (c) || c == '.';
|
||
namelen++)
|
||
;
|
||
return parse_number (namelen);
|
||
}
|
||
|
||
if (!is_idstart (c)) {
|
||
yyerror ("invalid token in expression");
|
||
return ERROR;
|
||
}
|
||
|
||
/* It is a name. See how long it is. */
|
||
|
||
for (namelen = 0;
|
||
is_idchar (tokstart[namelen]);
|
||
namelen++)
|
||
;
|
||
|
||
lexptr += 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. */
|
||
|
||
static int
|
||
parse_escape (string_ptr)
|
||
const char **string_ptr;
|
||
{
|
||
int c = *(*string_ptr)++;
|
||
switch (c)
|
||
{
|
||
case 'a':
|
||
return TARGET_BELL;
|
||
case 'b':
|
||
return TARGET_BS;
|
||
case 'e':
|
||
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 '^':
|
||
c = *(*string_ptr)++;
|
||
if (c == '\\')
|
||
c = parse_escape (string_ptr);
|
||
if (c == '?')
|
||
return 0177;
|
||
return (c & 0200) | (c & 037);
|
||
|
||
case '0':
|
||
case '1':
|
||
case '2':
|
||
case '3':
|
||
case '4':
|
||
case '5':
|
||
case '6':
|
||
case '7':
|
||
{
|
||
int i = c - '0';
|
||
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 << CHAR_TYPE_SIZE) - 1)) != 0)
|
||
{
|
||
i &= (1 << CHAR_TYPE_SIZE) - 1;
|
||
warning ("octal character constant does not fit in a byte");
|
||
}
|
||
return i;
|
||
}
|
||
case 'x':
|
||
{
|
||
int i = 0;
|
||
for (;;)
|
||
{
|
||
c = *(*string_ptr)++;
|
||
if (hex_p (c))
|
||
i = (i << 4) + hex_value (c);
|
||
else
|
||
{
|
||
(*string_ptr)--;
|
||
break;
|
||
}
|
||
}
|
||
if ((i & ~((1 << BITS_PER_UNIT) - 1)) != 0)
|
||
{
|
||
i &= (1 << BITS_PER_UNIT) - 1;
|
||
warning ("hex character constant does not fit in a byte");
|
||
}
|
||
return i;
|
||
}
|
||
default:
|
||
return c;
|
||
}
|
||
}
|
||
|
||
static void
|
||
yyerror (msgid)
|
||
const char *msgid;
|
||
{
|
||
error ("%s", _(msgid));
|
||
longjmp (parse_return_error, 1);
|
||
}
|
||
|
||
/* 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. */
|
||
|
||
int
|
||
parse_c_expression (string)
|
||
const 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 () */
|
||
}
|