JITDivGenerator.cpp [plain text]
#include "config.h"
#include "JITDivGenerator.h"
#if ENABLE(JIT)
#include "ArithProfile.h"
#include "JSCJSValueInlines.h"
#include "MathCommon.h"
namespace JSC {
void JITDivGenerator::loadOperand(CCallHelpers& jit, SnippetOperand& opr, JSValueRegs oprRegs, FPRReg destFPR)
{
if (opr.isConstInt32()) {
jit.move(CCallHelpers::Imm32(opr.asConstInt32()), m_scratchGPR);
jit.convertInt32ToDouble(m_scratchGPR, destFPR);
#if USE(JSVALUE64)
} else if (opr.isConstDouble()) {
jit.move(CCallHelpers::Imm64(opr.asRawBits()), m_scratchGPR);
jit.move64ToDouble(m_scratchGPR, destFPR);
#endif
} else {
if (!opr.definitelyIsNumber())
m_slowPathJumpList.append(jit.branchIfNotNumber(oprRegs, m_scratchGPR));
CCallHelpers::Jump notInt32 = jit.branchIfNotInt32(oprRegs);
jit.convertInt32ToDouble(oprRegs.payloadGPR(), destFPR);
CCallHelpers::Jump oprIsLoaded = jit.jump();
notInt32.link(&jit);
jit.unboxDoubleNonDestructive(oprRegs, destFPR, m_scratchGPR, m_scratchFPR);
oprIsLoaded.link(&jit);
}
}
void JITDivGenerator::generateFastPath(CCallHelpers& jit)
{
ASSERT(m_scratchGPR != InvalidGPRReg);
ASSERT(m_scratchGPR != m_left.payloadGPR());
ASSERT(m_scratchGPR != m_right.payloadGPR());
#if USE(JSVALUE32_64)
ASSERT(m_scratchGPR != m_left.tagGPR());
ASSERT(m_scratchGPR != m_right.tagGPR());
ASSERT(m_scratchFPR != InvalidFPRReg);
#endif
ASSERT(!m_didEmitFastPath);
if (!jit.supportsFloatingPoint())
return;
if (!m_leftOperand.mightBeNumber() || !m_rightOperand.mightBeNumber())
return;
ASSERT(!m_leftOperand.isConstInt32() || !m_rightOperand.isConstInt32());
m_didEmitFastPath = true;
loadOperand(jit, m_leftOperand, m_left, m_leftFPR);
#if USE(JSVALUE64)
std::optional<double> safeReciprocal;
if (m_rightOperand.isConst()) {
double constant = m_rightOperand.asConstNumber();
safeReciprocal = safeReciprocalForDivByConst(constant);
}
if (safeReciprocal) {
jit.move(CCallHelpers::Imm64(bitwise_cast<int64_t>(*safeReciprocal)), m_scratchGPR);
jit.move64ToDouble(m_scratchGPR, m_rightFPR);
jit.mulDouble(m_rightFPR, m_leftFPR);
} else
#endif
{
loadOperand(jit, m_rightOperand, m_right, m_rightFPR);
jit.divDouble(m_rightFPR, m_leftFPR);
}
CCallHelpers::JumpList notInt32;
jit.branchConvertDoubleToInt32(m_leftFPR, m_scratchGPR, notInt32, m_scratchFPR);
jit.boxInt32(m_scratchGPR, m_result);
m_endJumpList.append(jit.jump());
notInt32.link(&jit);
#if USE(JSVALUE64)
jit.moveDoubleTo64(m_leftFPR, m_scratchGPR);
CCallHelpers::Jump notDoubleZero = jit.branchTest64(CCallHelpers::NonZero, m_scratchGPR);
jit.move(GPRInfo::tagTypeNumberRegister, m_result.payloadGPR());
m_endJumpList.append(jit.jump());
notDoubleZero.link(&jit);
#endif
if (m_arithProfile)
jit.or32(CCallHelpers::TrustedImm32(ArithProfile::specialFastPathBit), CCallHelpers::AbsoluteAddress(m_arithProfile->addressOfBits()));
jit.boxDouble(m_leftFPR, m_result);
}
}
#endif // ENABLE(JIT)