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x86/x64: Search for exit jumps with instruction length decoder.

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Contributed by Peter Cawley.
This commit is contained in:
Mike Pall 2016-04-18 11:16:13 +02:00
parent e5b5e079c3
commit 73680a5fc7
1 changed files with 104 additions and 9 deletions
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113
src/lj_asm_x86.h
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@ -2776,6 +2776,106 @@ static void asm_setup_target(ASMState *as)
/* -- Trace patching ------------------------------------------------------ */
static const uint8_t map_op1[256] = {
0x92,0x92,0x92,0x92,0x52,0x45,0x51,0x51,0x92,0x92,0x92,0x92,0x52,0x45,0x51,0x20,
0x92,0x92,0x92,0x92,0x52,0x45,0x51,0x51,0x92,0x92,0x92,0x92,0x52,0x45,0x51,0x51,
0x92,0x92,0x92,0x92,0x52,0x45,0x10,0x51,0x92,0x92,0x92,0x92,0x52,0x45,0x10,0x51,
0x92,0x92,0x92,0x92,0x52,0x45,0x10,0x51,0x92,0x92,0x92,0x92,0x52,0x45,0x10,0x51,
#if LJ_64
0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x10,0x14,0x14,0x14,0x14,0x14,0x14,0x14,0x14,
#else
0x51,0x51,0x51,0x51,0x51,0x51,0x51,0x51,0x51,0x51,0x51,0x51,0x51,0x51,0x51,0x51,
#endif
0x51,0x51,0x51,0x51,0x51,0x51,0x51,0x51,0x51,0x51,0x51,0x51,0x51,0x51,0x51,0x51,
0x51,0x51,0x92,0x92,0x10,0x10,0x12,0x11,0x45,0x86,0x52,0x93,0x51,0x51,0x51,0x51,
0x52,0x52,0x52,0x52,0x52,0x52,0x52,0x52,0x52,0x52,0x52,0x52,0x52,0x52,0x52,0x52,
0x93,0x86,0x93,0x93,0x92,0x92,0x92,0x92,0x92,0x92,0x92,0x92,0x92,0x92,0x92,0x92,
0x51,0x51,0x51,0x51,0x51,0x51,0x51,0x51,0x51,0x51,0x47,0x51,0x51,0x51,0x51,0x51,
#if LJ_64
0x59,0x59,0x59,0x59,0x51,0x51,0x51,0x51,0x52,0x45,0x51,0x51,0x51,0x51,0x51,0x51,
#else
0x55,0x55,0x55,0x55,0x51,0x51,0x51,0x51,0x52,0x45,0x51,0x51,0x51,0x51,0x51,0x51,
#endif
0x52,0x52,0x52,0x52,0x52,0x52,0x52,0x52,0x05,0x05,0x05,0x05,0x05,0x05,0x05,0x05,
0x93,0x93,0x53,0x51,0x70,0x71,0x93,0x86,0x54,0x51,0x53,0x51,0x51,0x52,0x51,0x51,
0x92,0x92,0x92,0x92,0x52,0x52,0x51,0x51,0x92,0x92,0x92,0x92,0x92,0x92,0x92,0x92,
0x52,0x52,0x52,0x52,0x52,0x52,0x52,0x52,0x45,0x45,0x47,0x52,0x51,0x51,0x51,0x51,
0x10,0x51,0x10,0x10,0x51,0x51,0x63,0x66,0x51,0x51,0x51,0x51,0x51,0x51,0x92,0x92
};
static const uint8_t map_op2[256] = {
0x93,0x93,0x93,0x93,0x52,0x52,0x52,0x52,0x52,0x52,0x51,0x52,0x51,0x93,0x52,0x94,
0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,
0x53,0x53,0x53,0x53,0x53,0x53,0x53,0x53,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,
0x52,0x52,0x52,0x52,0x52,0x52,0x52,0x52,0x34,0x51,0x35,0x51,0x51,0x51,0x51,0x51,
0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,
0x53,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,
0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,
0x94,0x54,0x54,0x54,0x93,0x93,0x93,0x52,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,
0x46,0x46,0x46,0x46,0x46,0x46,0x46,0x46,0x46,0x46,0x46,0x46,0x46,0x46,0x46,0x46,
0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,
0x52,0x52,0x52,0x93,0x94,0x93,0x51,0x51,0x52,0x52,0x52,0x93,0x94,0x93,0x93,0x93,
0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x94,0x93,0x93,0x93,0x93,0x93,
0x93,0x93,0x94,0x93,0x94,0x94,0x94,0x93,0x52,0x52,0x52,0x52,0x52,0x52,0x52,0x52,
0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,
0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,
0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x93,0x52
};
static uint32_t asm_x86_inslen(const uint8_t* p)
{
uint32_t result = 0;
uint32_t prefixes = 0;
uint32_t x = map_op1[*p];
for (;;) {
switch (x >> 4) {
case 0: return result + x + (prefixes & 4);
case 1: prefixes |= x; x = map_op1[*++p]; result++; break;
case 2: x = map_op2[*++p]; break;
case 3: p++; goto mrm;
case 4: result -= (prefixes & 2); /* fallthrough */
case 5: return result + (x & 15);
case 6: /* Group 3. */
if (p[1] & 0x38) return result + 2;
if ((prefixes & 2) && (x == 0x66)) return result + 4;
return result + (x & 15);
case 7: /* VEX c4/c5. */
if (LJ_32 && p[1] < 0xc0) {
x = 2;
goto mrm;
}
if (x == 0x70) {
x = *++p & 0x1f;
result++;
if (x >= 2) {
p += 2;
result += 2;
goto mrm;
}
}
p++;
result++;
x = map_op2[*++p];
break;
case 8: result -= (prefixes & 2); /* fallthrough */
case 9: mrm: /* ModR/M and possibly SIB. */
result += (x & 15);
x = *++p;
switch (x >> 6) {
case 0: if ((x & 7) == 5) return result + 4; break;
case 1: result++; break;
case 2: result += 4; break;
case 3: return result;
}
if ((x & 7) == 4) {
result++;
if (x < 0x40 && (p[1] & 7) == 5) result += 4;
}
return result;
}
}
}
/* Patch exit jumps of existing machine code to a new target. */
void lj_asm_patchexit(jit_State *J, GCtrace *T, ExitNo exitno, MCode *target)
{
@ -2788,18 +2888,13 @@ void lj_asm_patchexit(jit_State *J, GCtrace *T, ExitNo exitno, MCode *target)
if (len > 5 && p[len-5] == XI_JMP && p+len-6 + *(int32_t *)(p+len-4) == px)
*(int32_t *)(p+len-4) = jmprel(p+len, target);
/* Do not patch parent exit for a stack check. Skip beyond vmstate update. */
for (; p < pe; p++)
if (*(uint32_t *)(p+(LJ_64 ? 3 : 2)) == stateaddr && p[0] == XI_MOVmi) {
p += LJ_64 ? 11 : 10;
for (; p < pe; p += asm_x86_inslen(p))
if (*(uint32_t *)(p+(LJ_64 ? 3 : 2)) == stateaddr && p[0] == XI_MOVmi)
break;
}
lua_assert(p < pe);
for (; p < pe; p++) {
if ((*(uint16_t *)p & 0xf0ff) == 0x800f && p + *(int32_t *)(p+2) == px) {
for (; p < pe; p += asm_x86_inslen(p))
if ((*(uint16_t *)p & 0xf0ff) == 0x800f && p + *(int32_t *)(p+2) == px)
*(int32_t *)(p+2) = jmprel(p+6, target);
p += 5;
}
}
lj_mcode_sync(T->mcode, T->mcode + T->szmcode);
lj_mcode_patch(J, mcarea, 1);
}