void ValueRep::emitRestore(AssemblyHelpers& jit, Reg reg) const
{
if (reg.isGPR()) {
switch (kind()) {
case LateRegister:
case Register:
if (isGPR())
jit.move(gpr(), reg.gpr());
else
jit.moveDoubleTo64(fpr(), reg.gpr());
break;
case Stack:
jit.load64(AssemblyHelpers::Address(GPRInfo::callFrameRegister, offsetFromFP()), reg.gpr());
break;
case Constant:
jit.move(AssemblyHelpers::TrustedImm64(value()), reg.gpr());
break;
default:
RELEASE_ASSERT_NOT_REACHED();
break;
}
return;
}
switch (kind()) {
case LateRegister:
case Register:
if (isGPR())
jit.move64ToDouble(gpr(), reg.fpr());
else
jit.moveDouble(fpr(), reg.fpr());
break;
case Stack:
jit.loadDouble(AssemblyHelpers::Address(GPRInfo::callFrameRegister, offsetFromFP()), reg.fpr());
break;
case Constant:
jit.move(AssemblyHelpers::TrustedImm64(value()), jit.scratchRegister());
jit.move64ToDouble(jit.scratchRegister(), reg.fpr());
break;
default:
RELEASE_ASSERT_NOT_REACHED();
break;
}
}
static void generateRegisterRestoration(AssemblyHelpers& jit)
{
#if ENABLE(FTL_JIT)
RegisterSet toSave = registersToPreserve();
ptrdiff_t offset = registerPreservationOffset();
ASSERT(!toSave.get(GPRInfo::regT4));
// We need to place the stack pointer back to where the caller thought they left it.
// But also, in order to recover the registers, we need to figure out how big the
// arguments area is.
jit.load32(
AssemblyHelpers::Address(
AssemblyHelpers::stackPointerRegister,
(JSStack::ArgumentCount - JSStack::CallerFrameAndPCSize) * sizeof(Register) + PayloadOffset),
GPRInfo::regT4);
jit.move(GPRInfo::regT4, GPRInfo::regT2);
jit.lshift32(AssemblyHelpers::TrustedImm32(3), GPRInfo::regT2);
jit.addPtr(AssemblyHelpers::TrustedImm32(offset), AssemblyHelpers::stackPointerRegister);
jit.addPtr(AssemblyHelpers::stackPointerRegister, GPRInfo::regT2);
// We saved things at:
//
// adjSP + (JSStack::CallFrameHeaderSize - JSStack::CallerFrameAndPCSize + NumArgs) * 8
//
// Where:
//
// adjSP = origSP - offset
//
// regT2 now points at:
//
// origSP + NumArgs * 8
// = adjSP + offset + NumArgs * 8
//
// So if we subtract offset and then add JSStack::CallFrameHeaderSize and subtract
// JSStack::CallerFrameAndPCSize, we'll get the thing we want.
ptrdiff_t currentOffset = -offset + sizeof(Register) * (
JSStack::CallFrameHeaderSize - JSStack::CallerFrameAndPCSize);
jit.loadPtr(AssemblyHelpers::Address(GPRInfo::regT2, currentOffset), GPRInfo::regT1);
for (GPRReg gpr = AssemblyHelpers::firstRegister(); gpr <= AssemblyHelpers::lastRegister(); gpr = static_cast<GPRReg>(gpr + 1)) {
if (!toSave.get(gpr))
continue;
currentOffset += sizeof(Register);
jit.load64(AssemblyHelpers::Address(GPRInfo::regT2, currentOffset), gpr);
}
for (FPRReg fpr = AssemblyHelpers::firstFPRegister(); fpr <= AssemblyHelpers::lastFPRegister(); fpr = static_cast<FPRReg>(fpr + 1)) {
if (!toSave.get(fpr))
continue;
currentOffset += sizeof(Register);
jit.loadDouble(AssemblyHelpers::Address(GPRInfo::regT2, currentOffset), fpr);
}
// Thunks like this rely on the ArgumentCount being intact. Pay it forward.
jit.store32(
GPRInfo::regT4,
AssemblyHelpers::Address(
AssemblyHelpers::stackPointerRegister,
(JSStack::ArgumentCount - JSStack::CallerFrameAndPCSize) * sizeof(Register) + PayloadOffset));
if (!ASSERT_DISABLED) {
AssemblyHelpers::Jump ok = jit.branchPtr(
AssemblyHelpers::Above, GPRInfo::regT1, AssemblyHelpers::TrustedImmPtr(static_cast<size_t>(0x1000)));
jit.abortWithReason(RPWUnreasonableJumpTarget);
ok.link(&jit);
}
jit.jump(GPRInfo::regT1);
#else // ENABLE(FTL_JIT)
UNUSED_PARAM(jit);
UNREACHABLE_FOR_PLATFORM();
#endif // ENABLE(FTL_JIT)
}