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/*
* IR - Lightweight JIT Compilation Framework
* (Native code patcher)
* Copyright (C) 2022 Zend by Perforce.
* Authors: Dmitry Stogov <dmitry@php.net>
*
* Based on Mike Pall's implementation for LuaJIT.
*/
#include "ir.h"
#include "ir_private.h"
#if defined(IR_TARGET_X86) || defined(IR_TARGET_X64)
static uint32_t _asm_x86_inslen(const uint8_t* p)
{
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,
#ifdef IR_TARGET_X64
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,
#ifdef IR_TARGET_X64
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
};
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) {
x = 2;
} else if ((prefixes & 2) && (x == 0x66)) {
x = 4;
}
goto mrm;
case 7: /* VEX c4/c5. */
#ifdef IR_TARGET_X86
if (p[1] < 0xc0) {
x = 2;
goto mrm;
}
#endif
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;
}
}
}
typedef IR_SET_ALIGNED(1, uint16_t unaligned_uint16_t);
typedef IR_SET_ALIGNED(1, int32_t unaligned_int32_t);
static int ir_patch_code(const void *code, size_t size, const void *from_addr, const void *to_addr)
{
int ret = 0;
uint8_t *p, *end;
p = (uint8_t*)code;
end = p + size - 4;
while (p < end) {
if ((*(unaligned_uint16_t*)p & 0xf0ff) == 0x800f && p + *(unaligned_int32_t*)(p+2) == (uint8_t*)from_addr - 6) {
*(unaligned_int32_t*)(p+2) = ((uint8_t*)to_addr - (p + 6));
ret++;
} else if (*p == 0xe9 && p + *(unaligned_int32_t*)(p+1) == (uint8_t*)from_addr - 5) {
*(unaligned_int32_t*)(p+1) = ((uint8_t*)to_addr - (p + 5));
ret++;
}
p += _asm_x86_inslen(p);
}
if (ret) {
ir_mem_flush((void*)code, size);
}
return ret;
}
#elif defined(IR_TARGET_AARCH64)
static int ir_patch_code(const void *code, size_t size, const void *from_addr, const void *to_addr)
{
int ret = 0;
uint8_t *p, *end;
const void *veneer = NULL;
ptrdiff_t delta;
end = (uint8_t*)code;
p = end + size;
while (p > end) {
uint32_t *ins_ptr;
uint32_t ins;
p -= 4;
ins_ptr = (uint32_t*)p;
ins = *ins_ptr;
if ((ins & 0xfc000000u) == 0x14000000u) {
// B (imm26:0..25)
delta = (uint32_t*)from_addr - ins_ptr;
if (((ins ^ (uint32_t)delta) & 0x01ffffffu) == 0) {
delta = (uint32_t*)to_addr - ins_ptr;
if (((delta + 0x02000000) >> 26) != 0) {
abort(); // branch target out of range
}
*ins_ptr = (ins & 0xfc000000u) | ((uint32_t)delta & 0x03ffffffu);
ret++;
if (!veneer) {
veneer = p;
}
}
} else if ((ins & 0xff000000u) == 0x54000000u ||
(ins & 0x7e000000u) == 0x34000000u) {
// B.cond, CBZ, CBNZ (imm19:5..23)
delta = (uint32_t*)from_addr - ins_ptr;
if (((ins ^ ((uint32_t)delta << 5)) & 0x00ffffe0u) == 0) {
delta = (uint32_t*)to_addr - ins_ptr;
if (((delta + 0x40000) >> 19) != 0) {
if (veneer) {
delta = (uint32_t*)veneer - ins_ptr;
if (((delta + 0x40000) >> 19) != 0) {
abort(); // branch target out of range
}
} else {
abort(); // branch target out of range
}
}
*ins_ptr = (ins & 0xff00001fu) | (((uint32_t)delta & 0x7ffffu) << 5);
ret++;
}
} else if ((ins & 0x7e000000u) == 0x36000000u) {
// TBZ, TBNZ (imm14:5..18)
delta = (uint32_t*)from_addr - ins_ptr;
if (((ins ^ ((uint32_t)delta << 5)) & 0x0007ffe0u) == 0) {
delta = (uint32_t*)to_addr - ins_ptr;
if (((delta + 0x2000) >> 14) != 0) {
if (veneer) {
delta = (uint32_t*)veneer - ins_ptr;
if (((delta + 0x2000) >> 14) != 0) {
abort(); // branch target out of range
}
} else {
abort(); // branch target out of range
}
}
*ins_ptr = (ins & 0xfff8001fu) | (((uint32_t)delta & 0x3fffu) << 5);
ret++;
}
}
}
if (ret) {
ir_mem_flush((void*)code, size);
}
return ret;
}
#endif
int ir_patch(const void *code, size_t size, uint32_t jmp_table_size, const void *from_addr, const void *to_addr)
{
int ret = 0;
if (jmp_table_size) {
const void **jmp_slot = (const void **)((char*)code + IR_ALIGNED_SIZE(size, sizeof(void*)));
do {
if (*jmp_slot == from_addr) {
*jmp_slot = to_addr;
ret++;
}
jmp_slot++;
} while (--jmp_table_size);
}
ret += ir_patch_code(code, size, from_addr, to_addr);
return ret;
}
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