ScratchRegisterAllocator.cpp [plain text]
#include "config.h"
#include "ScratchRegisterAllocator.h"
#if ENABLE(JIT)
#include "JSCInlines.h"
#include "VM.h"
namespace JSC {
ScratchRegisterAllocator::ScratchRegisterAllocator(const RegisterSet& usedRegisters)
: m_usedRegisters(usedRegisters)
, m_numberOfReusedRegisters(0)
{
}
ScratchRegisterAllocator::~ScratchRegisterAllocator() { }
void ScratchRegisterAllocator::lock(GPRReg reg)
{
unsigned index = GPRInfo::toIndex(reg);
if (index == GPRInfo::InvalidIndex)
return;
m_lockedRegisters.setGPRByIndex(index);
}
void ScratchRegisterAllocator::lock(FPRReg reg)
{
unsigned index = FPRInfo::toIndex(reg);
if (index == FPRInfo::InvalidIndex)
return;
m_lockedRegisters.setFPRByIndex(index);
}
template<typename BankInfo>
typename BankInfo::RegisterType ScratchRegisterAllocator::allocateScratch()
{
for (unsigned i = 0; i < BankInfo::numberOfRegisters; ++i) {
typename BankInfo::RegisterType reg = BankInfo::toRegister(i);
if (!m_lockedRegisters.get(reg)
&& !m_usedRegisters.get(reg)
&& !m_scratchRegisters.get(reg)) {
m_scratchRegisters.set(reg);
return reg;
}
}
for (unsigned i = 0; i < BankInfo::numberOfRegisters; ++i) {
typename BankInfo::RegisterType reg = BankInfo::toRegister(i);
if (!m_lockedRegisters.get(reg) && !m_scratchRegisters.get(reg)) {
m_scratchRegisters.set(reg);
m_numberOfReusedRegisters++;
return reg;
}
}
CRASH();
return static_cast<typename BankInfo::RegisterType>(-1);
}
GPRReg ScratchRegisterAllocator::allocateScratchGPR() { return allocateScratch<GPRInfo>(); }
FPRReg ScratchRegisterAllocator::allocateScratchFPR() { return allocateScratch<FPRInfo>(); }
void ScratchRegisterAllocator::preserveReusedRegistersByPushing(MacroAssembler& jit)
{
if (!didReuseRegisters())
return;
for (unsigned i = 0; i < FPRInfo::numberOfRegisters; ++i) {
FPRReg reg = FPRInfo::toRegister(i);
if (m_scratchRegisters.getFPRByIndex(i) && m_usedRegisters.get(reg))
jit.pushToSave(reg);
}
for (unsigned i = 0; i < GPRInfo::numberOfRegisters; ++i) {
GPRReg reg = GPRInfo::toRegister(i);
if (m_scratchRegisters.getGPRByIndex(i) && m_usedRegisters.get(reg))
jit.pushToSave(reg);
}
}
void ScratchRegisterAllocator::restoreReusedRegistersByPopping(MacroAssembler& jit)
{
if (!didReuseRegisters())
return;
for (unsigned i = GPRInfo::numberOfRegisters; i--;) {
GPRReg reg = GPRInfo::toRegister(i);
if (m_scratchRegisters.getGPRByIndex(i) && m_usedRegisters.get(reg))
jit.popToRestore(reg);
}
for (unsigned i = FPRInfo::numberOfRegisters; i--;) {
FPRReg reg = FPRInfo::toRegister(i);
if (m_scratchRegisters.getFPRByIndex(i) && m_usedRegisters.get(reg))
jit.popToRestore(reg);
}
}
RegisterSet ScratchRegisterAllocator::usedRegistersForCall() const
{
RegisterSet result = m_usedRegisters;
result.exclude(RegisterSet::calleeSaveRegisters());
result.exclude(RegisterSet::stackRegisters());
result.exclude(RegisterSet::reservedHardwareRegisters());
return result;
}
unsigned ScratchRegisterAllocator::desiredScratchBufferSizeForCall() const
{
return usedRegistersForCall().numberOfSetRegisters() * sizeof(JSValue);
}
void ScratchRegisterAllocator::preserveUsedRegistersToScratchBufferForCall(MacroAssembler& jit, ScratchBuffer* scratchBuffer, GPRReg scratchGPR)
{
RegisterSet usedRegisters = usedRegistersForCall();
if (!usedRegisters.numberOfSetRegisters())
return;
unsigned count = 0;
for (GPRReg reg = MacroAssembler::firstRegister(); reg <= MacroAssembler::lastRegister(); reg = MacroAssembler::nextRegister(reg)) {
if (usedRegisters.get(reg))
jit.storePtr(reg, static_cast<EncodedJSValue*>(scratchBuffer->dataBuffer()) + (count++));
if (GPRInfo::toIndex(reg) != GPRInfo::InvalidIndex
&& scratchGPR == InvalidGPRReg
&& !m_lockedRegisters.get(reg) && !m_scratchRegisters.get(reg))
scratchGPR = reg;
}
RELEASE_ASSERT(scratchGPR != InvalidGPRReg);
for (FPRReg reg = MacroAssembler::firstFPRegister(); reg <= MacroAssembler::lastFPRegister(); reg = MacroAssembler::nextFPRegister(reg)) {
if (usedRegisters.get(reg)) {
jit.move(MacroAssembler::TrustedImmPtr(static_cast<EncodedJSValue*>(scratchBuffer->dataBuffer()) + (count++)), scratchGPR);
jit.storeDouble(reg, scratchGPR);
}
}
RELEASE_ASSERT(count * sizeof(JSValue) == desiredScratchBufferSizeForCall());
jit.move(MacroAssembler::TrustedImmPtr(scratchBuffer->activeLengthPtr()), scratchGPR);
jit.storePtr(MacroAssembler::TrustedImmPtr(static_cast<size_t>(count * sizeof(JSValue))), scratchGPR);
}
void ScratchRegisterAllocator::restoreUsedRegistersFromScratchBufferForCall(MacroAssembler& jit, ScratchBuffer* scratchBuffer, GPRReg scratchGPR)
{
RegisterSet usedRegisters = usedRegistersForCall();
if (!usedRegisters.numberOfSetRegisters())
return;
if (scratchGPR == InvalidGPRReg) {
for (unsigned i = GPRInfo::numberOfRegisters; i--;) {
if (m_lockedRegisters.getGPRByIndex(i) || m_scratchRegisters.getGPRByIndex(i))
continue;
scratchGPR = GPRInfo::toRegister(i);
break;
}
}
RELEASE_ASSERT(scratchGPR != InvalidGPRReg);
jit.move(MacroAssembler::TrustedImmPtr(scratchBuffer->activeLengthPtr()), scratchGPR);
jit.storePtr(MacroAssembler::TrustedImmPtr(0), scratchGPR);
unsigned count = usedRegisters.numberOfSetGPRs();
for (FPRReg reg = MacroAssembler::firstFPRegister(); reg <= MacroAssembler::lastFPRegister(); reg = MacroAssembler::nextFPRegister(reg)) {
if (usedRegisters.get(reg)) {
jit.move(MacroAssembler::TrustedImmPtr(static_cast<EncodedJSValue*>(scratchBuffer->dataBuffer()) + (count++)), scratchGPR);
jit.loadDouble(scratchGPR, reg);
}
}
count = 0;
for (GPRReg reg = MacroAssembler::firstRegister(); reg <= MacroAssembler::lastRegister(); reg = MacroAssembler::nextRegister(reg)) {
if (usedRegisters.get(reg))
jit.loadPtr(static_cast<EncodedJSValue*>(scratchBuffer->dataBuffer()) + (count++), reg);
}
}
}
#endif // ENABLE(JIT)