1059 lines
26 KiB
C
1059 lines
26 KiB
C
/* Parse C expressions for CCCP.
|
||
Copyright (C) 1987, 92, 94, 95, 97, 98, 1999 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!
|
||
|
||
Written by Per Bothner 1994. */
|
||
|
||
/* Parse a C expression from text in a string */
|
||
|
||
#include "config.h"
|
||
#include "system.h"
|
||
#include "cpplib.h"
|
||
|
||
#ifdef MULTIBYTE_CHARS
|
||
#include <locale.h>
|
||
#endif
|
||
|
||
#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
|
||
|
||
#define MAX_CHAR_TYPE_MASK (MAX_CHAR_TYPE_SIZE < HOST_BITS_PER_WIDEST_INT \
|
||
? (~ (~ (HOST_WIDEST_INT) 0 << MAX_CHAR_TYPE_SIZE)) \
|
||
: ~ (HOST_WIDEST_INT) 0)
|
||
|
||
#define MAX_WCHAR_TYPE_MASK (MAX_WCHAR_TYPE_SIZE < HOST_BITS_PER_WIDEST_INT \
|
||
? ~ (~ (HOST_WIDEST_INT) 0 << MAX_WCHAR_TYPE_SIZE) \
|
||
: ~ (HOST_WIDEST_INT) 0)
|
||
|
||
/* 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 PARAMS ((cpp_reader *));
|
||
static HOST_WIDEST_INT left_shift PARAMS ((cpp_reader *, HOST_WIDEST_INT, int, unsigned HOST_WIDEST_INT));
|
||
static HOST_WIDEST_INT right_shift PARAMS ((cpp_reader *, HOST_WIDEST_INT, int, unsigned HOST_WIDEST_INT));
|
||
|
||
#define ERROR 299
|
||
#define OROR 300
|
||
#define ANDAND 301
|
||
#define EQUAL 302
|
||
#define NOTEQUAL 303
|
||
#define LEQ 304
|
||
#define GEQ 305
|
||
#define LSH 306
|
||
#define RSH 307
|
||
#define NAME 308
|
||
#define INT 309
|
||
#define CHAR 310
|
||
|
||
#define LEFT_OPERAND_REQUIRED 1
|
||
#define RIGHT_OPERAND_REQUIRED 2
|
||
#define HAVE_VALUE 4
|
||
/* SKIP_OPERAND is set for '&&' '||' '?' and ':' when the
|
||
following operand should be short-circuited instead of evaluated. */
|
||
#define SKIP_OPERAND 8
|
||
/*#define UNSIGNEDP 16*/
|
||
|
||
struct operation {
|
||
short op;
|
||
char rprio; /* Priority of op (relative to it right operand). */
|
||
char flags;
|
||
char unsignedp; /* true if value should be treated as unsigned */
|
||
HOST_WIDEST_INT value; /* The value logically "right" of op. */
|
||
};
|
||
|
||
/* Parse and convert an integer for #if. Accepts decimal, hex, or octal
|
||
with or without size suffixes. */
|
||
|
||
static struct operation
|
||
parse_number (pfile, start, end)
|
||
cpp_reader *pfile;
|
||
U_CHAR *start;
|
||
U_CHAR *end;
|
||
{
|
||
struct operation op;
|
||
U_CHAR *p = start;
|
||
int c;
|
||
unsigned HOST_WIDEST_INT n = 0, nd, MAX_over_base;
|
||
int base = 10;
|
||
int overflow = 0;
|
||
int digit, largest_digit = 0;
|
||
int spec_long = 0;
|
||
|
||
op.unsignedp = 0;
|
||
|
||
if (p[0] == '0')
|
||
{
|
||
if (end - start >= 3 && (p[1] == 'x' || p[1] == 'X'))
|
||
{
|
||
p += 2;
|
||
base = 16;
|
||
}
|
||
else
|
||
{
|
||
p += 1;
|
||
base = 8;
|
||
}
|
||
}
|
||
|
||
/* Some buggy compilers (e.g. MPW C) seem to need both casts. */
|
||
MAX_over_base = (((unsigned HOST_WIDEST_INT) -1)
|
||
/ ((unsigned HOST_WIDEST_INT) base));
|
||
|
||
while (p < end)
|
||
{
|
||
c = *p++;
|
||
|
||
if (c >= '0' && c <= '9')
|
||
digit = c - '0';
|
||
else if (base == 16 && c >= 'a' && c <= 'f') /* FIXME: assumes ASCII */
|
||
digit = c - 'a' + 10;
|
||
else if (base == 16 && c >= 'A' && c <= 'F')
|
||
digit = c - 'A' + 10;
|
||
else if (c == '.')
|
||
{
|
||
/* It's a float since it contains a point. */
|
||
cpp_error (pfile,
|
||
"floating point numbers are not allowed in #if expressions");
|
||
goto error;
|
||
}
|
||
else
|
||
{
|
||
/* `l' means long, and `u' means unsigned. */
|
||
for (;;)
|
||
{
|
||
if (c == 'l' || c == 'L')
|
||
spec_long++;
|
||
else if (c == 'u' || c == 'U')
|
||
op.unsignedp++;
|
||
else
|
||
{
|
||
/* Decrement p here so that the error for an invalid number
|
||
will be generated below in the case where this is the
|
||
last character in the buffer. */
|
||
p--;
|
||
break;
|
||
}
|
||
if (p == end)
|
||
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 |= MAX_over_base < n || nd < n;
|
||
n = nd;
|
||
}
|
||
|
||
if (p != end)
|
||
{
|
||
cpp_error (pfile, "invalid number in #if expression");
|
||
goto error;
|
||
}
|
||
else if (spec_long > (CPP_OPTIONS (pfile)->c89 ? 1 : 2))
|
||
{
|
||
cpp_error (pfile, "too many `l' suffixes in integer constant");
|
||
goto error;
|
||
}
|
||
else if (op.unsignedp > 1)
|
||
{
|
||
cpp_error (pfile, "too many `u' suffixes in integer constant");
|
||
goto error;
|
||
}
|
||
|
||
if (base <= largest_digit)
|
||
cpp_pedwarn (pfile, "integer constant contains digits beyond the radix");
|
||
|
||
if (overflow)
|
||
cpp_pedwarn (pfile, "integer constant out of range");
|
||
|
||
/* If too big to be signed, consider it unsigned. */
|
||
else if ((HOST_WIDEST_INT) n < 0 && ! op.unsignedp)
|
||
{
|
||
if (base == 10)
|
||
cpp_warning (pfile,
|
||
"integer constant is so large that it is unsigned");
|
||
op.unsignedp = 1;
|
||
}
|
||
|
||
op.value = n;
|
||
op.op = INT;
|
||
return op;
|
||
|
||
error:
|
||
op.op = ERROR;
|
||
return op;
|
||
}
|
||
|
||
/* Parse and convert a character constant for #if. Understands backslash
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||
escapes (\n, \031) and multibyte characters (if so configured). */
|
||
static struct operation
|
||
parse_charconst (pfile, start, end)
|
||
cpp_reader *pfile;
|
||
U_CHAR *start;
|
||
U_CHAR *end;
|
||
{
|
||
struct operation op;
|
||
HOST_WIDEST_INT result = 0;
|
||
int num_chars = 0;
|
||
int num_bits;
|
||
unsigned int width = MAX_CHAR_TYPE_SIZE, mask = MAX_CHAR_TYPE_MASK;
|
||
int max_chars;
|
||
U_CHAR *ptr = start;
|
||
|
||
/* FIXME: Should use reentrant multibyte functions. */
|
||
#ifdef MULTIBYTE_CHARS
|
||
wchar_t c = (wchar_t)-1;
|
||
(void) mbtowc (NULL_PTR, NULL_PTR, 0);
|
||
#else
|
||
int c = -1;
|
||
#endif
|
||
|
||
if (*ptr == 'L')
|
||
{
|
||
++ptr;
|
||
width = MAX_WCHAR_TYPE_SIZE, mask = MAX_WCHAR_TYPE_MASK;
|
||
}
|
||
max_chars = MAX_LONG_TYPE_SIZE / width;
|
||
|
||
++ptr; /* skip initial quote */
|
||
|
||
while (ptr < end)
|
||
{
|
||
#ifndef MULTIBYTE_CHARS
|
||
c = *ptr++;
|
||
#else
|
||
ptr += mbtowc (&c, ptr, end - ptr);
|
||
#endif
|
||
if (c == '\'' || c == '\0')
|
||
break;
|
||
else if (c == '\\')
|
||
{
|
||
/* Hopefully valid assumption: if mbtowc returns a backslash,
|
||
we are in initial shift state. No valid escape-sequence
|
||
character can take us out of initial shift state or begin
|
||
an unshifted multibyte char, so cpp_parse_escape doesn't
|
||
need to know about multibyte chars. */
|
||
|
||
c = cpp_parse_escape (pfile, (char **) &ptr, mask);
|
||
if (width < HOST_BITS_PER_INT
|
||
&& (unsigned int) c >= (unsigned int)(1 << width))
|
||
cpp_pedwarn (pfile, "escape sequence out of range for character");
|
||
}
|
||
|
||
/* Merge character into result; ignore excess chars. */
|
||
if (++num_chars <= max_chars)
|
||
{
|
||
if (width < HOST_BITS_PER_INT)
|
||
result = (result << width) | (c & ((1 << width) - 1));
|
||
else
|
||
result = c;
|
||
}
|
||
}
|
||
|
||
if (num_chars == 0)
|
||
{
|
||
cpp_error (pfile, "empty character constant");
|
||
goto error;
|
||
}
|
||
else if (c != '\'')
|
||
{
|
||
/* cpp_get_token has already emitted an error if !traditional. */
|
||
if (! CPP_TRADITIONAL (pfile))
|
||
cpp_error (pfile, "malformatted character constant");
|
||
goto error;
|
||
}
|
||
else if (num_chars > max_chars)
|
||
{
|
||
cpp_error (pfile, "character constant too long");
|
||
goto error;
|
||
}
|
||
else if (num_chars != 1 && ! CPP_TRADITIONAL (pfile))
|
||
cpp_warning (pfile, "multi-character character constant");
|
||
|
||
/* If char type is signed, sign-extend the constant. */
|
||
num_bits = num_chars * width;
|
||
|
||
if (cpp_lookup (pfile, (U_CHAR *)"__CHAR_UNSIGNED__",
|
||
sizeof ("__CHAR_UNSIGNED__")-1, -1)
|
||
|| ((result >> (num_bits - 1)) & 1) == 0)
|
||
op.value = result & ((unsigned HOST_WIDEST_INT) ~0
|
||
>> (HOST_BITS_PER_WIDEST_INT - num_bits));
|
||
else
|
||
op.value = result | ~((unsigned HOST_WIDEST_INT) ~0
|
||
>> (HOST_BITS_PER_WIDEST_INT - num_bits));
|
||
|
||
/* This is always a signed type. */
|
||
op.unsignedp = 0;
|
||
op.op = CHAR;
|
||
return op;
|
||
|
||
error:
|
||
op.op = ERROR;
|
||
return op;
|
||
}
|
||
|
||
|
||
struct token {
|
||
char *operator;
|
||
int token;
|
||
};
|
||
|
||
static struct token tokentab2[] = {
|
||
{"&&", ANDAND},
|
||
{"||", OROR},
|
||
{"<<", LSH},
|
||
{">>", RSH},
|
||
{"==", EQUAL},
|
||
{"!=", NOTEQUAL},
|
||
{"<=", LEQ},
|
||
{">=", GEQ},
|
||
{"++", ERROR},
|
||
{"--", ERROR},
|
||
{NULL, ERROR}
|
||
};
|
||
|
||
/* Read one token. */
|
||
|
||
static struct operation
|
||
cpp_lex (pfile, skip_evaluation)
|
||
cpp_reader *pfile;
|
||
int skip_evaluation;
|
||
{
|
||
U_CHAR c;
|
||
struct token *toktab;
|
||
enum cpp_token token;
|
||
struct operation op;
|
||
U_CHAR *tok_start, *tok_end;
|
||
int old_written;
|
||
|
||
retry:
|
||
|
||
old_written = CPP_WRITTEN (pfile);
|
||
cpp_skip_hspace (pfile);
|
||
c = CPP_BUF_PEEK (CPP_BUFFER (pfile));
|
||
if (c == '#')
|
||
{
|
||
op.op = INT;
|
||
op.value = cpp_read_check_assertion (pfile);
|
||
return op;
|
||
}
|
||
|
||
if (c == '\n')
|
||
{
|
||
op.op = 0;
|
||
return op;
|
||
}
|
||
|
||
token = cpp_get_token (pfile);
|
||
tok_start = pfile->token_buffer + old_written;
|
||
tok_end = CPP_PWRITTEN (pfile);
|
||
pfile->limit = tok_start;
|
||
switch (token)
|
||
{
|
||
case CPP_EOF: /* Should not happen ... */
|
||
case CPP_VSPACE:
|
||
op.op = 0;
|
||
return op;
|
||
case CPP_POP:
|
||
if (CPP_BUFFER (pfile)->fname != NULL)
|
||
{
|
||
op.op = 0;
|
||
return op;
|
||
}
|
||
cpp_pop_buffer (pfile);
|
||
goto retry;
|
||
case CPP_HSPACE:
|
||
case CPP_COMMENT:
|
||
goto retry;
|
||
case CPP_NUMBER:
|
||
return parse_number (pfile, tok_start, tok_end);
|
||
case CPP_STRING:
|
||
cpp_error (pfile, "string constants not allowed in #if expressions");
|
||
op.op = ERROR;
|
||
return op;
|
||
case CPP_CHAR:
|
||
return parse_charconst (pfile, tok_start, tok_end);
|
||
|
||
case CPP_NAME:
|
||
op.op = INT;
|
||
op.unsignedp = 0;
|
||
op.value = 0;
|
||
if (strcmp (tok_start, "defined"))
|
||
{
|
||
if (CPP_WARN_UNDEF (pfile) && !skip_evaluation)
|
||
cpp_warning (pfile, "`%.*s' is not defined",
|
||
(int) (tok_end - tok_start), tok_start);
|
||
}
|
||
else
|
||
{
|
||
int paren = 0, len;
|
||
cpp_buffer *ip = CPP_BUFFER (pfile);
|
||
U_CHAR *tok;
|
||
|
||
cpp_skip_hspace (pfile);
|
||
if (*ip->cur == '(')
|
||
{
|
||
paren++;
|
||
ip->cur++; /* Skip over the paren */
|
||
cpp_skip_hspace (pfile);
|
||
}
|
||
|
||
if (!is_idstart[*ip->cur])
|
||
goto oops;
|
||
if (ip->cur[0] == 'L' && (ip->cur[1] == '\'' || ip->cur[1] == '"'))
|
||
goto oops;
|
||
tok = ip->cur;
|
||
while (is_idchar[*ip->cur])
|
||
++ip->cur;
|
||
len = ip->cur - tok;
|
||
cpp_skip_hspace (pfile);
|
||
if (paren)
|
||
{
|
||
if (*ip->cur != ')')
|
||
goto oops;
|
||
++ip->cur;
|
||
}
|
||
if (cpp_lookup (pfile, tok, len, -1))
|
||
op.value = 1;
|
||
|
||
}
|
||
return op;
|
||
|
||
oops:
|
||
cpp_error (pfile, "`defined' without an identifier");
|
||
return op;
|
||
|
||
case CPP_OTHER:
|
||
/* See if it is a special token of length 2. */
|
||
if (tok_start + 2 == tok_end)
|
||
{
|
||
for (toktab = tokentab2; toktab->operator != NULL; toktab++)
|
||
if (tok_start[0] == toktab->operator[0]
|
||
&& tok_start[1] == toktab->operator[1])
|
||
break;
|
||
if (toktab->token == ERROR)
|
||
cpp_error (pfile, "`%s' not allowed in operand of `#if'",
|
||
tok_start);
|
||
op.op = toktab->token;
|
||
return op;
|
||
}
|
||
/* fall through */
|
||
default:
|
||
op.op = *tok_start;
|
||
return op;
|
||
}
|
||
}
|
||
|
||
|
||
/* 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. */
|
||
|
||
HOST_WIDEST_INT
|
||
cpp_parse_escape (pfile, string_ptr, result_mask)
|
||
cpp_reader *pfile;
|
||
char **string_ptr;
|
||
HOST_WIDEST_INT result_mask;
|
||
{
|
||
register int c = *(*string_ptr)++;
|
||
switch (c)
|
||
{
|
||
case 'a':
|
||
return TARGET_BELL;
|
||
case 'b':
|
||
return TARGET_BS;
|
||
case 'e':
|
||
case 'E':
|
||
if (CPP_OPTIONS (pfile)->pedantic)
|
||
cpp_pedwarn (pfile, "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 HOST_WIDEST_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 != (i & result_mask))
|
||
{
|
||
i &= result_mask;
|
||
cpp_pedwarn (pfile, "octal escape sequence out of range");
|
||
}
|
||
return i;
|
||
}
|
||
case 'x':
|
||
{
|
||
register unsigned HOST_WIDEST_INT i = 0, overflow = 0;
|
||
register int 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)
|
||
cpp_error (pfile, "\\x used with no following hex digits");
|
||
if (overflow | (i != (i & result_mask)))
|
||
{
|
||
i &= result_mask;
|
||
cpp_pedwarn (pfile, "hex escape sequence out of range");
|
||
}
|
||
return i;
|
||
}
|
||
default:
|
||
return c;
|
||
}
|
||
}
|
||
|
||
static void
|
||
integer_overflow (pfile)
|
||
cpp_reader *pfile;
|
||
{
|
||
if (CPP_PEDANTIC (pfile))
|
||
cpp_pedwarn (pfile, "integer overflow in preprocessor expression");
|
||
}
|
||
|
||
static HOST_WIDEST_INT
|
||
left_shift (pfile, a, unsignedp, b)
|
||
cpp_reader *pfile;
|
||
HOST_WIDEST_INT a;
|
||
int unsignedp;
|
||
unsigned HOST_WIDEST_INT b;
|
||
{
|
||
if (b >= HOST_BITS_PER_WIDEST_INT)
|
||
{
|
||
if (! unsignedp && a != 0)
|
||
integer_overflow (pfile);
|
||
return 0;
|
||
}
|
||
else if (unsignedp)
|
||
return (unsigned HOST_WIDEST_INT) a << b;
|
||
else
|
||
{
|
||
HOST_WIDEST_INT l = a << b;
|
||
if (l >> b != a)
|
||
integer_overflow (pfile);
|
||
return l;
|
||
}
|
||
}
|
||
|
||
static HOST_WIDEST_INT
|
||
right_shift (pfile, a, unsignedp, b)
|
||
cpp_reader *pfile ATTRIBUTE_UNUSED;
|
||
HOST_WIDEST_INT a;
|
||
int unsignedp;
|
||
unsigned HOST_WIDEST_INT b;
|
||
{
|
||
if (b >= HOST_BITS_PER_WIDEST_INT)
|
||
return unsignedp ? 0 : a >> (HOST_BITS_PER_WIDEST_INT - 1);
|
||
else if (unsignedp)
|
||
return (unsigned HOST_WIDEST_INT) a >> b;
|
||
else
|
||
return a >> b;
|
||
}
|
||
|
||
/* These priorities are all even, so we can handle associatively. */
|
||
#define PAREN_INNER_PRIO 0
|
||
#define COMMA_PRIO 4
|
||
#define COND_PRIO (COMMA_PRIO+2)
|
||
#define OROR_PRIO (COND_PRIO+2)
|
||
#define ANDAND_PRIO (OROR_PRIO+2)
|
||
#define OR_PRIO (ANDAND_PRIO+2)
|
||
#define XOR_PRIO (OR_PRIO+2)
|
||
#define AND_PRIO (XOR_PRIO+2)
|
||
#define EQUAL_PRIO (AND_PRIO+2)
|
||
#define LESS_PRIO (EQUAL_PRIO+2)
|
||
#define SHIFT_PRIO (LESS_PRIO+2)
|
||
#define PLUS_PRIO (SHIFT_PRIO+2)
|
||
#define MUL_PRIO (PLUS_PRIO+2)
|
||
#define UNARY_PRIO (MUL_PRIO+2)
|
||
#define PAREN_OUTER_PRIO (UNARY_PRIO+2)
|
||
|
||
#define COMPARE(OP) \
|
||
top->unsignedp = 0;\
|
||
top->value = (unsigned1 || unsigned2) \
|
||
? (unsigned HOST_WIDEST_INT) v1 OP (unsigned HOST_WIDEST_INT) v2 : (v1 OP v2)
|
||
|
||
/* Parse and evaluate a C expression, reading from PFILE.
|
||
Returns the value of the expression. */
|
||
|
||
HOST_WIDEST_INT
|
||
cpp_parse_expr (pfile)
|
||
cpp_reader *pfile;
|
||
{
|
||
/* The implementation is an operator precedence parser,
|
||
i.e. a bottom-up parser, using a stack for not-yet-reduced tokens.
|
||
|
||
The stack base is 'stack', and the current stack pointer is 'top'.
|
||
There is a stack element for each operator (only),
|
||
and the most recently pushed operator is 'top->op'.
|
||
An operand (value) is stored in the 'value' field of the stack
|
||
element of the operator that precedes it.
|
||
In that case the 'flags' field has the HAVE_VALUE flag set. */
|
||
|
||
#define INIT_STACK_SIZE 20
|
||
struct operation init_stack[INIT_STACK_SIZE];
|
||
struct operation *stack = init_stack;
|
||
struct operation *limit = stack + INIT_STACK_SIZE;
|
||
register struct operation *top = stack;
|
||
int lprio, rprio = 0;
|
||
int skip_evaluation = 0;
|
||
|
||
top->rprio = 0;
|
||
top->flags = 0;
|
||
for (;;)
|
||
{
|
||
struct operation op;
|
||
char flags = 0;
|
||
|
||
/* Read a token */
|
||
op = cpp_lex (pfile, skip_evaluation);
|
||
|
||
/* See if the token is an operand, in which case go to set_value.
|
||
If the token is an operator, figure out its left and right
|
||
priorities, and then goto maybe_reduce. */
|
||
|
||
switch (op.op)
|
||
{
|
||
case NAME:
|
||
cpp_fatal (pfile, "internal error: cpp_lex returns a NAME");
|
||
goto syntax_error;
|
||
case INT: case CHAR:
|
||
top->value = op.value;
|
||
top->unsignedp = op.unsignedp;
|
||
goto set_value;
|
||
case 0:
|
||
lprio = 0; goto maybe_reduce;
|
||
case '+': case '-':
|
||
/* Is this correct if unary ? FIXME */
|
||
flags = RIGHT_OPERAND_REQUIRED;
|
||
lprio = PLUS_PRIO; rprio = lprio + 1; goto maybe_reduce;
|
||
case '!': case '~':
|
||
flags = RIGHT_OPERAND_REQUIRED;
|
||
rprio = UNARY_PRIO; lprio = rprio + 1; goto maybe_reduce;
|
||
case '*': case '/': case '%':
|
||
lprio = MUL_PRIO; goto binop;
|
||
case '<': case '>': case LEQ: case GEQ:
|
||
lprio = LESS_PRIO; goto binop;
|
||
case EQUAL: case NOTEQUAL:
|
||
lprio = EQUAL_PRIO; goto binop;
|
||
case LSH: case RSH:
|
||
lprio = SHIFT_PRIO; goto binop;
|
||
case '&': lprio = AND_PRIO; goto binop;
|
||
case '^': lprio = XOR_PRIO; goto binop;
|
||
case '|': lprio = OR_PRIO; goto binop;
|
||
case ANDAND: lprio = ANDAND_PRIO; goto binop;
|
||
case OROR: lprio = OROR_PRIO; goto binop;
|
||
case ',':
|
||
lprio = COMMA_PRIO; goto binop;
|
||
case '(':
|
||
lprio = PAREN_OUTER_PRIO; rprio = PAREN_INNER_PRIO;
|
||
goto maybe_reduce;
|
||
case ')':
|
||
lprio = PAREN_INNER_PRIO; rprio = PAREN_OUTER_PRIO;
|
||
goto maybe_reduce;
|
||
case ':':
|
||
lprio = COND_PRIO; rprio = COND_PRIO;
|
||
goto maybe_reduce;
|
||
case '?':
|
||
lprio = COND_PRIO + 1; rprio = COND_PRIO;
|
||
goto maybe_reduce;
|
||
case ERROR:
|
||
goto syntax_error;
|
||
binop:
|
||
flags = LEFT_OPERAND_REQUIRED|RIGHT_OPERAND_REQUIRED;
|
||
rprio = lprio + 1;
|
||
goto maybe_reduce;
|
||
default:
|
||
cpp_error (pfile, "invalid character in #if");
|
||
goto syntax_error;
|
||
}
|
||
|
||
set_value:
|
||
/* Push a value onto the stack. */
|
||
if (top->flags & HAVE_VALUE)
|
||
{
|
||
cpp_error (pfile, "syntax error in #if");
|
||
goto syntax_error;
|
||
}
|
||
top->flags |= HAVE_VALUE;
|
||
continue;
|
||
|
||
maybe_reduce:
|
||
/* Push an operator, and check if we can reduce now. */
|
||
while (top->rprio > lprio)
|
||
{
|
||
HOST_WIDEST_INT v1 = top[-1].value, v2 = top[0].value;
|
||
int unsigned1 = top[-1].unsignedp, unsigned2 = top[0].unsignedp;
|
||
top--;
|
||
if ((top[1].flags & LEFT_OPERAND_REQUIRED)
|
||
&& ! (top[0].flags & HAVE_VALUE))
|
||
{
|
||
cpp_error (pfile, "syntax error - missing left operand");
|
||
goto syntax_error;
|
||
}
|
||
if ((top[1].flags & RIGHT_OPERAND_REQUIRED)
|
||
&& ! (top[1].flags & HAVE_VALUE))
|
||
{
|
||
cpp_error (pfile, "syntax error - missing right operand");
|
||
goto syntax_error;
|
||
}
|
||
/* top[0].value = (top[1].op)(v1, v2);*/
|
||
switch (top[1].op)
|
||
{
|
||
case '+':
|
||
if (!(top->flags & HAVE_VALUE))
|
||
{ /* Unary '+' */
|
||
top->value = v2;
|
||
top->unsignedp = unsigned2;
|
||
top->flags |= HAVE_VALUE;
|
||
}
|
||
else
|
||
{
|
||
top->value = v1 + v2;
|
||
top->unsignedp = unsigned1 || unsigned2;
|
||
if (! top->unsignedp && ! skip_evaluation
|
||
&& ! possible_sum_sign (v1, v2, top->value))
|
||
integer_overflow (pfile);
|
||
}
|
||
break;
|
||
case '-':
|
||
if (!(top->flags & HAVE_VALUE))
|
||
{ /* Unary '-' */
|
||
top->value = - v2;
|
||
if (!skip_evaluation && (top->value & v2) < 0 && !unsigned2)
|
||
integer_overflow (pfile);
|
||
top->unsignedp = unsigned2;
|
||
top->flags |= HAVE_VALUE;
|
||
}
|
||
else
|
||
{ /* Binary '-' */
|
||
top->value = v1 - v2;
|
||
top->unsignedp = unsigned1 || unsigned2;
|
||
if (! top->unsignedp && ! skip_evaluation
|
||
&& ! possible_sum_sign (top->value, v2, v1))
|
||
integer_overflow (pfile);
|
||
}
|
||
break;
|
||
case '*':
|
||
top->unsignedp = unsigned1 || unsigned2;
|
||
if (top->unsignedp)
|
||
top->value = (unsigned HOST_WIDEST_INT) v1 * v2;
|
||
else if (!skip_evaluation)
|
||
{
|
||
top->value = v1 * v2;
|
||
if (v1
|
||
&& (top->value / v1 != v2
|
||
|| (top->value & v1 & v2) < 0))
|
||
integer_overflow (pfile);
|
||
}
|
||
break;
|
||
case '/':
|
||
if (skip_evaluation)
|
||
break;
|
||
if (v2 == 0)
|
||
{
|
||
cpp_error (pfile, "division by zero in #if");
|
||
v2 = 1;
|
||
}
|
||
top->unsignedp = unsigned1 || unsigned2;
|
||
if (top->unsignedp)
|
||
top->value = (unsigned HOST_WIDEST_INT) v1 / v2;
|
||
else
|
||
{
|
||
top->value = v1 / v2;
|
||
if ((top->value & v1 & v2) < 0)
|
||
integer_overflow (pfile);
|
||
}
|
||
break;
|
||
case '%':
|
||
if (skip_evaluation)
|
||
break;
|
||
if (v2 == 0)
|
||
{
|
||
cpp_error (pfile, "division by zero in #if");
|
||
v2 = 1;
|
||
}
|
||
top->unsignedp = unsigned1 || unsigned2;
|
||
if (top->unsignedp)
|
||
top->value = (unsigned HOST_WIDEST_INT) v1 % v2;
|
||
else
|
||
top->value = v1 % v2;
|
||
break;
|
||
case '!':
|
||
if (top->flags & HAVE_VALUE)
|
||
{
|
||
cpp_error (pfile, "syntax error");
|
||
goto syntax_error;
|
||
}
|
||
top->value = ! v2;
|
||
top->unsignedp = 0;
|
||
top->flags |= HAVE_VALUE;
|
||
break;
|
||
case '~':
|
||
if (top->flags & HAVE_VALUE)
|
||
{
|
||
cpp_error (pfile, "syntax error");
|
||
goto syntax_error;
|
||
}
|
||
top->value = ~ v2;
|
||
top->unsignedp = unsigned2;
|
||
top->flags |= HAVE_VALUE;
|
||
break;
|
||
case '<': COMPARE(<); break;
|
||
case '>': COMPARE(>); break;
|
||
case LEQ: COMPARE(<=); break;
|
||
case GEQ: COMPARE(>=); break;
|
||
case EQUAL:
|
||
top->value = (v1 == v2);
|
||
top->unsignedp = 0;
|
||
break;
|
||
case NOTEQUAL:
|
||
top->value = (v1 != v2);
|
||
top->unsignedp = 0;
|
||
break;
|
||
case LSH:
|
||
if (skip_evaluation)
|
||
break;
|
||
top->unsignedp = unsigned1;
|
||
if (v2 < 0 && ! unsigned2)
|
||
top->value = right_shift (pfile, v1, unsigned1, -v2);
|
||
else
|
||
top->value = left_shift (pfile, v1, unsigned1, v2);
|
||
break;
|
||
case RSH:
|
||
if (skip_evaluation)
|
||
break;
|
||
top->unsignedp = unsigned1;
|
||
if (v2 < 0 && ! unsigned2)
|
||
top->value = left_shift (pfile, v1, unsigned1, -v2);
|
||
else
|
||
top->value = right_shift (pfile, v1, unsigned1, v2);
|
||
break;
|
||
#define LOGICAL(OP) \
|
||
top->value = v1 OP v2;\
|
||
top->unsignedp = unsigned1 || unsigned2;
|
||
case '&': LOGICAL(&); break;
|
||
case '^': LOGICAL(^); break;
|
||
case '|': LOGICAL(|); break;
|
||
case ANDAND:
|
||
top->value = v1 && v2; top->unsignedp = 0;
|
||
if (!v1) skip_evaluation--;
|
||
break;
|
||
case OROR:
|
||
top->value = v1 || v2; top->unsignedp = 0;
|
||
if (v1) skip_evaluation--;
|
||
break;
|
||
case ',':
|
||
if (CPP_PEDANTIC (pfile))
|
||
cpp_pedwarn (pfile, "comma operator in operand of `#if'");
|
||
top->value = v2;
|
||
top->unsignedp = unsigned2;
|
||
break;
|
||
case '(': case '?':
|
||
cpp_error (pfile, "syntax error in #if");
|
||
goto syntax_error;
|
||
case ':':
|
||
if (top[0].op != '?')
|
||
{
|
||
cpp_error (pfile,
|
||
"syntax error ':' without preceding '?'");
|
||
goto syntax_error;
|
||
}
|
||
else if (! (top[1].flags & HAVE_VALUE)
|
||
|| !(top[-1].flags & HAVE_VALUE)
|
||
|| !(top[0].flags & HAVE_VALUE))
|
||
{
|
||
cpp_error (pfile, "bad syntax for ?: operator");
|
||
goto syntax_error;
|
||
}
|
||
else
|
||
{
|
||
top--;
|
||
if (top->value) skip_evaluation--;
|
||
top->value = top->value ? v1 : v2;
|
||
top->unsignedp = unsigned1 || unsigned2;
|
||
}
|
||
break;
|
||
case ')':
|
||
if ((top[1].flags & HAVE_VALUE)
|
||
|| ! (top[0].flags & HAVE_VALUE)
|
||
|| top[0].op != '('
|
||
|| (top[-1].flags & HAVE_VALUE))
|
||
{
|
||
cpp_error (pfile, "mismatched parentheses in #if");
|
||
goto syntax_error;
|
||
}
|
||
else
|
||
{
|
||
top--;
|
||
top->value = v1;
|
||
top->unsignedp = unsigned1;
|
||
top->flags |= HAVE_VALUE;
|
||
}
|
||
break;
|
||
default:
|
||
cpp_error (pfile,
|
||
(top[1].op >= ' ' && top[1].op <= '~'
|
||
? "unimplemented operator '%c'\n"
|
||
: "unimplemented operator '\\%03o'\n"),
|
||
top[1].op);
|
||
}
|
||
}
|
||
if (op.op == 0)
|
||
{
|
||
if (top != stack)
|
||
cpp_error (pfile, "internal error in #if expression");
|
||
if (stack != init_stack)
|
||
free (stack);
|
||
return top->value;
|
||
}
|
||
top++;
|
||
|
||
/* Check for and handle stack overflow. */
|
||
if (top == limit)
|
||
{
|
||
struct operation *new_stack;
|
||
int old_size = (char *) limit - (char *) stack;
|
||
int new_size = 2 * old_size;
|
||
if (stack != init_stack)
|
||
new_stack = (struct operation *) xrealloc (stack, new_size);
|
||
else
|
||
{
|
||
new_stack = (struct operation *) xmalloc (new_size);
|
||
bcopy ((char *) stack, (char *) new_stack, old_size);
|
||
}
|
||
stack = new_stack;
|
||
top = (struct operation *) ((char *) new_stack + old_size);
|
||
limit = (struct operation *) ((char *) new_stack + new_size);
|
||
}
|
||
|
||
top->flags = flags;
|
||
top->rprio = rprio;
|
||
top->op = op.op;
|
||
if ((op.op == OROR && top[-1].value)
|
||
|| (op.op == ANDAND && !top[-1].value)
|
||
|| (op.op == '?' && !top[-1].value))
|
||
{
|
||
skip_evaluation++;
|
||
}
|
||
else if (op.op == ':')
|
||
{
|
||
if (top[-2].value) /* Was condition true? */
|
||
skip_evaluation++;
|
||
else
|
||
skip_evaluation--;
|
||
}
|
||
}
|
||
syntax_error:
|
||
if (stack != init_stack)
|
||
free (stack);
|
||
skip_rest_of_line (pfile);
|
||
return 0;
|
||
}
|