void
wasm::ToggleProfiling(const Code& code, const CodeRange& codeRange, bool enabled)
{
if (!codeRange.isFunction())
return;
uint8_t* codeBase = code.segment().base();
uint8_t* profilingEntry = codeBase + codeRange.funcProfilingEntry();
uint8_t* tableProfilingJump = codeBase + codeRange.funcTableProfilingJump();
uint8_t* profilingJump = codeBase + codeRange.funcProfilingJump();
uint8_t* profilingEpilogue = codeBase + codeRange.funcProfilingEpilogue();
if (enabled) {
MacroAssembler::patchNopToNearJump(tableProfilingJump, profilingEntry);
MacroAssembler::patchNopToNearJump(profilingJump, profilingEpilogue);
} else {
MacroAssembler::patchNearJumpToNop(tableProfilingJump);
MacroAssembler::patchNearJumpToNop(profilingJump);
}
}
// Replace all the nops in all the epilogues of asm.js functions with jumps
// to the profiling epilogues.
void
wasm::EnableProfilingEpilogue(const Module& module, const CodeRange& codeRange, bool enabled)
{
if (!codeRange.isFunction())
return;
uint8_t* jump = module.code() + codeRange.functionProfilingJump();
uint8_t* profilingEpilogue = module.code() + codeRange.funcProfilingEpilogue();
#if defined(JS_CODEGEN_X86) || defined(JS_CODEGEN_X64)
// An unconditional jump with a 1 byte offset immediate has the opcode
// 0x90. The offset is relative to the address of the instruction after
// the jump. 0x66 0x90 is the canonical two-byte nop.
ptrdiff_t jumpImmediate = profilingEpilogue - jump - 2;
MOZ_ASSERT(jumpImmediate > 0 && jumpImmediate <= 127);
if (enabled) {
MOZ_ASSERT(jump[0] == 0x66);
MOZ_ASSERT(jump[1] == 0x90);
jump[0] = 0xeb;
jump[1] = jumpImmediate;
} else {
MOZ_ASSERT(jump[0] == 0xeb);
MOZ_ASSERT(jump[1] == jumpImmediate);
jump[0] = 0x66;
jump[1] = 0x90;
}
#elif defined(JS_CODEGEN_ARM)
if (enabled) {
MOZ_ASSERT(reinterpret_cast<Instruction*>(jump)->is<InstNOP>());
new (jump) InstBImm(BOffImm(profilingEpilogue - jump), Assembler::Always);
} else {
MOZ_ASSERT(reinterpret_cast<Instruction*>(jump)->is<InstBImm>());
new (jump) InstNOP();
}
#elif defined(JS_CODEGEN_ARM64)
(void)jump;
(void)profilingEpilogue;
MOZ_CRASH();
#elif defined(JS_CODEGEN_MIPS32)
Instruction* instr = (Instruction*)jump;
if (enabled) {
Assembler::WriteLuiOriInstructions(instr, instr->next(),
ScratchRegister, (uint32_t)profilingEpilogue);
instr[2] = InstReg(op_special, ScratchRegister, zero, zero, ff_jr);
} else {
for (unsigned i = 0; i < 3; i++)
instr[i].makeNop();
}
#elif defined(JS_CODEGEN_MIPS64)
Instruction* instr = (Instruction*)jump;
if (enabled) {
Assembler::WriteLoad64Instructions(instr, ScratchRegister, (uint64_t)profilingEpilogue);
instr[4] = InstReg(op_special, ScratchRegister, zero, zero, ff_jr);
} else {
for (unsigned i = 0; i < 5; i++)
instr[i].makeNop();
}
#elif defined(JS_CODEGEN_NONE)
MOZ_CRASH();
#else
# error "Missing architecture"
#endif
}