mirror/nasm
2
0
Fork 0
mirror of https://github.com/netwide-assembler/nasm.git synced 2025-04-24 19:00:23 +08:00
Code Issues Packages Projects Releases Wiki Activity

BR 2887108: Use overflow_ helper to catch inappropriate imm optimization

Browse Source 
We should use overflow_ helpers before check if an immediate
operand fit a type range, otherwise we may loose high bits.

For example when we assemble the following instruction

	imul eax,eax,0x10000

with -Ox passed we optimze it up to imm8 though it must be imm32.

Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>
This commit is contained in:
Cyrill Gorcunov 2009-10-31 10:34:43 +03:00
parent 4ea846623a
commit 41208028ff
1 changed files with 9 additions and 8 deletions

17
parser.c

@ -855,11 +855,10 @@ restart_parse:
result->oprs[operand].segment = NO_SEG; /* don't care again */
result->oprs[operand].wrt = NO_SEG; /* still don't care */
/* Be optimistic */
if(optimizing >= 0 && !(result->oprs[operand].type & STRICT))
{
/* Be optimistic */
result->oprs[operand].type |= SBYTE16 | SBYTE32 | SBYTE64;
}
} else if (is_reloc(value)) { /* it's immediate */
result->oprs[operand].type |= IMMEDIATE;
result->oprs[operand].offset = reloc_value(value);
@ -874,12 +873,14 @@ restart_parse:
int32_t v32 = (int32_t)v64;
int16_t v16 = (int16_t)v32;
if (v64 >= -128 && v64 <= 127)
if (v64 >= -128 && v64 <= 127)
result->oprs[operand].type |= SBYTE64;
if (v32 >= -128 && v32 <= 127)
result->oprs[operand].type |= SBYTE32;
if (v16 >= -128 && v16 <= 127)
result->oprs[operand].type |= SBYTE16;
if (!overflow_signed(v64, sizeof(v32)))
if (v32 >= -128 && v32 <= 127)
result->oprs[operand].type |= SBYTE32;
if (!overflow_signed(v64, sizeof(v16)))
if (v16 >= -128 && v16 <= 127)
result->oprs[operand].type |= SBYTE16;
}
}
} else { /* it's a register */