From f46ffce4f8f5de9e6b39877b398fd5f3d82b43ce Mon Sep 17 00:00:00 2001 From: Richard Stallman Date: Thu, 17 Sep 1992 21:11:17 +0000 Subject: (parse_escape): Diagnose '\x' with no digits. Diagnose integer overflow when parsing \x escapes. From-SVN: r2147 --- gcc/cexp.y | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) (limited to 'gcc') diff --git a/gcc/cexp.y b/gcc/cexp.y index c0fbca5..9530a37 100644 --- a/gcc/cexp.y +++ b/gcc/cexp.y @@ -803,23 +803,28 @@ parse_escape (string_ptr) } case 'x': { - register int i = 0; + register unsigned i = 0, overflow = 0, digits_found = 0, digit; for (;;) { c = *(*string_ptr)++; if (c >= '0' && c <= '9') - i = (i << 4) + c - '0'; + digit = c - '0'; else if (c >= 'a' && c <= 'f') - i = (i << 4) + c - 'a' + 10; + digit = c - 'a' + 10; else if (c >= 'A' && c <= 'F') - i = (i << 4) + c - 'A' + 10; + digit = c - 'A' + 10; else { (*string_ptr)--; break; } + overflow |= i ^ (i << 4 >> 4); + i = (i << 4) + digit; + digits_found = 1; } - if ((i & ~((1 << BITS_PER_UNIT) - 1)) != 0) + 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"); -- cgit v1.1