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665 lines (596 loc) · 31.7 KB
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/*
* Copyright (C) 2019-2023 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#pragma once
#if ENABLE(WEBASSEMBLY_BBQJIT)
#include "WasmBBQJIT.h"
#include "WasmCallingConvention.h"
#include "WasmCompilationContext.h"
#include "WasmExceptionType.h"
#include "WasmFunctionParser.h"
#include "WasmLimits.h"
#include "js/JSWebAssemblyInstance.h"
#include <wtf/CheckedArithmetic.h>
#include <wtf/Scope.h>
namespace JSC { namespace Wasm { namespace BBQJITImpl {
template<typename Functor>
auto BBQJIT::emitCheckAndPrepareAndMaterializePointerApply(Value pointer, uint64_t uoffset, uint32_t sizeOfOperation, uint8_t memoryIndex, NOESCAPE const Functor& functor) -> decltype(auto)
{
if (m_info.memory(memoryIndex).doesAccessOverflow(uoffset, sizeOfOperation)) {
recordJumpToThrowException(ExceptionType::OutOfBoundsMemoryAccess, m_jit.jump());
return functor(CCallHelpers::Address(wasmBaseMemoryPointer, 0));
}
uint64_t boundary = static_cast<uint64_t>(sizeOfOperation) + uoffset - 1;
Width accessWidth = widthForBytes(sizeOfOperation);
ScratchScope<1, 0> scratches(*this);
Location pointerLocation;
std::optional<ScratchScope<2, 0>> nonZeroMemoryScratches;
GPRReg baseRegister = wasmBaseMemoryPointer;
GPRReg boundsCheckingSizeRegister = wasmBoundsCheckingSizeRegister;
if (memoryIndex) {
nonZeroMemoryScratches.emplace(*this);
baseRegister = nonZeroMemoryScratches->gpr(0);
boundsCheckingSizeRegister = nonZeroMemoryScratches->gpr(1);
m_jit.loadPtr(
Address(GPRInfo::wasmContextInstancePointer, JSWebAssemblyInstance::offsetOfCachedMemoryBaseSizePair(memoryIndex)),
baseRegister
);
m_jit.loadPtr(
Address(GPRInfo::wasmContextInstancePointer, JSWebAssemblyInstance::offsetOfCachedMemoryBaseSizePair(memoryIndex) + sizeof(UCPURegister)),
boundsCheckingSizeRegister
);
}
if (pointer.isConst()) {
uint64_t constantPointer = m_info.memory(memoryIndex).isMemory64() ? pointer.asI64() : static_cast<uint32_t>(pointer.asI32());
if (WTF::sumOverflows<uint64_t>(constantPointer, boundary))
recordJumpToThrowException(ExceptionType::OutOfBoundsMemoryAccess, m_jit.jump());
else {
uint64_t finalOffset = constantPointer + uoffset;
if (finalOffset <= static_cast<uint64_t>(std::numeric_limits<int32_t>::max()) && B3::Air::Arg::isValidAddrForm(B3::Air::Move, static_cast<int32_t>(finalOffset), accessWidth)) {
switch (m_info.memoryModeForAccess(memoryIndex, m_mode)) {
case MemoryMode::BoundsChecking: {
m_jit.move(TrustedImmPtr(constantPointer + boundary), wasmScratchGPR);
recordJumpToThrowException(ExceptionType::OutOfBoundsMemoryAccess, m_jit.branchPtr(RelationalCondition::AboveOrEqual, wasmScratchGPR, boundsCheckingSizeRegister));
break;
}
case MemoryMode::Signaling: {
RELEASE_ASSERT(!m_info.memory(memoryIndex).isMemory64());
// FIXME: it seems like this check is covered by the constantPointer + boundary >= maximum check below?
if (uoffset >= Memory::fastMappedRedzoneBytes()) {
uint64_t maximum = m_info.memory(memoryIndex).maximum() ? m_info.memory(memoryIndex).maximum().bytes() : std::numeric_limits<uint32_t>::max();
if ((constantPointer + boundary) >= maximum)
recordJumpToThrowException(ExceptionType::OutOfBoundsMemoryAccess, m_jit.jump());
}
break;
}
}
return functor(CCallHelpers::Address(baseRegister, static_cast<int32_t>(finalOffset)));
}
}
pointerLocation = Location::fromGPR(scratches.gpr(0));
emitMoveConst(pointer, pointerLocation);
} else
pointerLocation = loadIfNecessary(pointer);
ASSERT(pointerLocation.isGPR());
// FIXME: for clarity we should probably rename m_mode to m_memory0Mode or something similar
switch (m_info.memoryModeForAccess(memoryIndex, m_mode)) {
case MemoryMode::BoundsChecking: {
// We're not using signal handling only when the memory is not shared.
// Regardless of signaling, we must check that no memory access exceeds the current memory size.
if (m_info.memory(memoryIndex).isMemory64()) {
if (boundary) {
m_jit.move(TrustedImmPtr(boundary), wasmScratchGPR);
Jump overflow = m_jit.branchAddPtr(ResultCondition::Carry, pointerLocation.asGPR(), wasmScratchGPR);
recordJumpToThrowException(ExceptionType::OutOfBoundsMemoryAccess, overflow);
} else
m_jit.move(pointerLocation.asGPR(), wasmScratchGPR);
} else {
m_jit.zeroExtend32ToWord(pointerLocation.asGPR(), wasmScratchGPR);
if (boundary)
m_jit.addPtr(TrustedImmPtr(boundary), wasmScratchGPR);
}
recordJumpToThrowException(ExceptionType::OutOfBoundsMemoryAccess, m_jit.branchPtr(RelationalCondition::AboveOrEqual, wasmScratchGPR, boundsCheckingSizeRegister));
break;
}
case MemoryMode::Signaling: {
RELEASE_ASSERT_WITH_SECURITY_IMPLICATION(!m_info.memory(memoryIndex).isMemory64());
// We've virtually mapped 4GiB+redzone for this memory. Only the user-allocated pages are addressable, contiguously in range [0, current],
// and everything above is mapped PROT_NONE. We don't need to perform any explicit bounds check in the 4GiB range because WebAssembly register
// memory accesses are 32-bit. However WebAssembly register + offset accesses perform the addition in 64-bit which can push an access above
// the 32-bit limit (the offset is unsigned 32-bit). The redzone will catch most small offsets, and we'll explicitly bounds check any
// register + large offset access. We don't think this will be generated frequently.
//
// We could check that register + large offset doesn't exceed 4GiB+redzone since that's technically the limit we need to avoid overflowing the
// PROT_NONE region, but it's better if we use a smaller immediate because it can codegens better. We know that anything equal to or greater
// than the declared 'maximum' will trap, so we can compare against that number. If there was no declared 'maximum' then we still know that
// any access equal to or greater than 4GiB will trap, no need to add the redzone.
if (boundary >= Memory::fastMappedRedzoneBytes()) {
RELEASE_ASSERT_WITH_SECURITY_IMPLICATION(!m_info.memory(memoryIndex).isMemory64());
uint64_t maximum = m_info.memory(memoryIndex).maximum() ? m_info.memory(memoryIndex).maximum().bytes() : std::numeric_limits<uint32_t>::max();
m_jit.zeroExtend32ToWord(pointerLocation.asGPR(), wasmScratchGPR);
if (boundary)
m_jit.addPtr(TrustedImmPtr(boundary), wasmScratchGPR);
recordJumpToThrowException(ExceptionType::OutOfBoundsMemoryAccess, m_jit.branchPtr(RelationalCondition::AboveOrEqual, wasmScratchGPR, TrustedImmPtr(static_cast<int64_t>(maximum))));
}
break;
}
}
bool canUseOffsetForm = uoffset <= static_cast<uint64_t>(std::numeric_limits<int32_t>::max()) && B3::Air::Arg::isValidAddrForm(B3::Air::Move, static_cast<int32_t>(uoffset), accessWidth);
#if CPU(ARM64)
if (canUseOffsetForm) {
if (m_info.memory(memoryIndex).isMemory64())
return functor(CCallHelpers::BaseIndex(baseRegister, pointerLocation.asGPR(), CCallHelpers::TimesOne, static_cast<int32_t>(uoffset)));
return functor(CCallHelpers::BaseIndex(baseRegister, pointerLocation.asGPR(), CCallHelpers::TimesOne, static_cast<int32_t>(uoffset), CCallHelpers::Extend::ZExt32));
}
if (m_info.memory(memoryIndex).isMemory64())
m_jit.addPtr(baseRegister, pointerLocation.asGPR(), wasmScratchGPR);
else
m_jit.addZeroExtend64(baseRegister, pointerLocation.asGPR(), wasmScratchGPR);
#else
if (m_info.memory(memoryIndex).isMemory64())
m_jit.addPtr(baseRegister, pointerLocation.asGPR(), wasmScratchGPR);
else {
m_jit.zeroExtend32ToWord(pointerLocation.asGPR(), wasmScratchGPR);
m_jit.addPtr(baseRegister, wasmScratchGPR);
}
#endif
if (canUseOffsetForm)
return functor(Address(wasmScratchGPR, static_cast<int32_t>(uoffset)));
// FIXME: We (potentially) already computed this above before adding the boundary, we should preserve that add result and use it again here
m_jit.addPtr(TrustedImmPtr(uoffset), wasmScratchGPR);
return functor(Address(wasmScratchGPR));
}
#if CPU(X86_64)
static inline RegisterSet clobbersForDivX86()
{
static RegisterSet x86DivClobbers;
static std::once_flag flag;
std::call_once(
flag,
[]() {
RegisterSet builder;
builder.add(X86Registers::eax, IgnoreVectors);
builder.add(X86Registers::edx, IgnoreVectors);
x86DivClobbers = builder;
});
return x86DivClobbers;
}
#define PREPARE_FOR_MOD_OR_DIV \
do { \
for (JSC::Reg reg : clobbersForDivX86()) \
clobber(reg); \
} while (false); \
ScratchScope<0, 0> scratches(*this, clobbersForDivX86())
#else
#define PREPARE_FOR_MOD_OR_DIV
#endif
#if CPU(X86_64)
template<typename IntType, bool IsMod>
void BBQJIT::emitModOrDiv(Value& lhs, Location lhsLocation, Value& rhs, Location rhsLocation, Value&, Location resultLocation)
{
// FIXME: We currently don't do nearly as sophisticated instruction selection on Intel as we do on other platforms,
// but there's no good reason we can't. We should probably port over the isel in the future if it seems to yield
// dividends.
constexpr bool isSigned = std::is_signed<IntType>();
constexpr bool is32 = sizeof(IntType) == 4;
ASSERT(lhsLocation.isRegister() || rhsLocation.isRegister());
if (lhs.isConst())
emitMoveConst(lhs, lhsLocation = Location::fromGPR(wasmScratchGPR));
else if (rhs.isConst())
emitMoveConst(rhs, rhsLocation = Location::fromGPR(wasmScratchGPR));
ASSERT(lhsLocation.isRegister() && rhsLocation.isRegister());
ASSERT(resultLocation.isRegister());
ASSERT(lhsLocation.asGPR() != X86Registers::eax && lhsLocation.asGPR() != X86Registers::edx);
ASSERT(rhsLocation.asGPR() != X86Registers::eax && rhsLocation.asGPR() != X86Registers::edx);
ScratchScope<2, 0> scratches(*this, lhsLocation, rhsLocation, resultLocation);
Jump toDiv, toEnd;
Jump isZero = is32
? m_jit.branchTest32(ResultCondition::Zero, rhsLocation.asGPR())
: m_jit.branchTest64(ResultCondition::Zero, rhsLocation.asGPR());
recordJumpToThrowException(ExceptionType::DivisionByZero, isZero);
if constexpr (isSigned) {
if constexpr (is32)
m_jit.compare32(RelationalCondition::Equal, rhsLocation.asGPR(), TrustedImm32(-1), scratches.gpr(0));
else
m_jit.compare64(RelationalCondition::Equal, rhsLocation.asGPR(), TrustedImm32(-1), scratches.gpr(0));
if constexpr (is32)
m_jit.compare32(RelationalCondition::Equal, lhsLocation.asGPR(), TrustedImm32(std::numeric_limits<int32_t>::min()), scratches.gpr(1));
else {
m_jit.move(TrustedImm64(std::numeric_limits<int64_t>::min()), scratches.gpr(1));
m_jit.compare64(RelationalCondition::Equal, lhsLocation.asGPR(), scratches.gpr(1), scratches.gpr(1));
}
m_jit.and64(scratches.gpr(0), scratches.gpr(1));
if constexpr (IsMod) {
toDiv = m_jit.branchTest64(ResultCondition::Zero, scratches.gpr(1));
// In this case, WASM doesn't want us to fault, but x86 will. So we set the result ourselves.
if constexpr (is32)
m_jit.xor32(resultLocation.asGPR(), resultLocation.asGPR());
else
m_jit.xor64(resultLocation.asGPR(), resultLocation.asGPR());
toEnd = m_jit.jump();
} else {
Jump isNegativeOne = m_jit.branchTest64(ResultCondition::NonZero, scratches.gpr(1));
recordJumpToThrowException(ExceptionType::IntegerOverflow, isNegativeOne);
}
}
if (toDiv.isSet())
toDiv.link(&m_jit);
m_jit.move(lhsLocation.asGPR(), X86Registers::eax);
if constexpr (is32 && isSigned) {
m_jit.x86ConvertToDoubleWord32();
m_jit.x86Div32(rhsLocation.asGPR());
} else if constexpr (is32) {
m_jit.xor32(X86Registers::edx, X86Registers::edx);
m_jit.x86UDiv32(rhsLocation.asGPR());
} else if constexpr (isSigned) {
m_jit.x86ConvertToQuadWord64();
m_jit.x86Div64(rhsLocation.asGPR());
} else {
m_jit.xor64(X86Registers::edx, X86Registers::edx);
m_jit.x86UDiv64(rhsLocation.asGPR());
}
if constexpr (IsMod)
m_jit.move(X86Registers::edx, resultLocation.asGPR());
else
m_jit.move(X86Registers::eax, resultLocation.asGPR());
if (toEnd.isSet())
toEnd.link(&m_jit);
}
#else
template<typename IntType, bool IsMod>
void BBQJIT::emitModOrDiv(Value& lhs, Location lhsLocation, Value& rhs, Location rhsLocation, Value&, Location resultLocation)
{
constexpr bool isSigned = std::is_signed<IntType>();
constexpr bool is32 = sizeof(IntType) == 4;
ASSERT(lhsLocation.isRegister() || rhsLocation.isRegister());
ASSERT(resultLocation.isRegister());
bool checkedForZero = false, checkedForNegativeOne = false;
if (rhs.isConst()) {
int64_t divisor = is32 ? rhs.asI32() : rhs.asI64();
if (!divisor) {
emitThrowException(ExceptionType::DivisionByZero);
return;
}
if (divisor == 1) {
if constexpr (IsMod) {
// N % 1 == 0
if constexpr (is32)
m_jit.xor32(resultLocation.asGPR(), resultLocation.asGPR());
else
m_jit.xor64(resultLocation.asGPR(), resultLocation.asGPR());
} else
m_jit.move(lhsLocation.asGPR(), resultLocation.asGPR());
return;
}
if (divisor == -1) {
// Check for INT_MIN / -1 case, and throw an IntegerOverflow exception if it occurs
if (!IsMod && isSigned) {
Jump jump = is32
? m_jit.branch32(RelationalCondition::Equal, lhsLocation.asGPR(), TrustedImm32(std::numeric_limits<int32_t>::min()))
: m_jit.branch64(RelationalCondition::Equal, lhsLocation.asGPR(), TrustedImm64(std::numeric_limits<int64_t>::min()));
recordJumpToThrowException(ExceptionType::IntegerOverflow, jump);
}
if constexpr (isSigned) {
if constexpr (IsMod) {
// N % 1 == 0
if constexpr (is32)
m_jit.xor32(resultLocation.asGPR(), resultLocation.asGPR());
else
m_jit.xor64(resultLocation.asGPR(), resultLocation.asGPR());
return;
}
if constexpr (is32)
m_jit.neg32(lhsLocation.asGPR(), resultLocation.asGPR());
else
m_jit.neg64(lhsLocation.asGPR(), resultLocation.asGPR());
return;
}
// Fall through to general case.
} else {
using UnsignedInt = std::make_unsigned_t<IntType>;
bool divisorIsNegative = isSigned && divisor < 0;
UnsignedInt magnitude = divisorIsNegative
? static_cast<UnsignedInt>(WTF::negate(static_cast<IntType>(divisor)))
: static_cast<UnsignedInt>(divisor);
if (isPowerOfTwo(magnitude)) {
unsigned shiftAmount = WTF::fastLog2(magnitude);
if constexpr (IsMod) {
if constexpr (isSigned) {
// This constructs an extra operand with log2(divisor) bits equal to the sign bit of the dividend. If the dividend
// is positive, this is zero and adding it achieves nothing; but if the dividend is negative, this is equal to the
// divisor minus one, which is the exact amount of bias we need to get the correct result. Computing this for both
// positive and negative dividends lets us elide branching, but more importantly allows us to save a register by
// not needing an extra multiplySub at the end.
if constexpr (is32) {
m_jit.rshift32(lhsLocation.asGPR(), TrustedImm32(31), wasmScratchGPR);
m_jit.urshift32(wasmScratchGPR, TrustedImm32(32 - shiftAmount), wasmScratchGPR);
m_jit.add32(wasmScratchGPR, lhsLocation.asGPR(), resultLocation.asGPR());
} else {
m_jit.rshift64(lhsLocation.asGPR(), TrustedImm32(63), wasmScratchGPR);
m_jit.urshift64(wasmScratchGPR, TrustedImm32(64 - shiftAmount), wasmScratchGPR);
m_jit.add64(wasmScratchGPR, lhsLocation.asGPR(), resultLocation.asGPR());
}
lhsLocation = resultLocation;
}
if constexpr (is32)
m_jit.and32(Imm32(magnitude - 1), lhsLocation.asGPR(), resultLocation.asGPR());
else
m_jit.and64(TrustedImm64(magnitude - 1), lhsLocation.asGPR(), resultLocation.asGPR());
if constexpr (isSigned) {
// The extra operand we computed is still in wasmScratchGPR - now we can subtract it from the result to get the
// correct answer.
if constexpr (is32)
m_jit.sub32(resultLocation.asGPR(), wasmScratchGPR, resultLocation.asGPR());
else
m_jit.sub64(resultLocation.asGPR(), wasmScratchGPR, resultLocation.asGPR());
}
return;
}
if constexpr (isSigned) {
// If we are doing signed division, we need to bias the dividend for negative numbers.
if constexpr (is32)
m_jit.add32(TrustedImm32(magnitude - 1), lhsLocation.asGPR(), wasmScratchGPR);
else
m_jit.add64(TrustedImm64(magnitude - 1), lhsLocation.asGPR(), wasmScratchGPR);
// moveConditionally seems to be faster than a branch here, even if it's well predicted.
if (is32)
m_jit.moveConditionally32(RelationalCondition::GreaterThanOrEqual, lhsLocation.asGPR(), TrustedImm32(0), lhsLocation.asGPR(), wasmScratchGPR, wasmScratchGPR);
else
m_jit.moveConditionally64(RelationalCondition::GreaterThanOrEqual, lhsLocation.asGPR(), TrustedImm32(0), lhsLocation.asGPR(), wasmScratchGPR, wasmScratchGPR);
lhsLocation = Location::fromGPR(wasmScratchGPR);
}
// Emit the actual division instruction: arithmetic shift if signed,
// logical shift if unsigned
if constexpr (isSigned) {
if constexpr (is32)
m_jit.rshift32(lhsLocation.asGPR(), m_jit.trustedImm32ForShift(Imm32(shiftAmount)), resultLocation.asGPR());
else
m_jit.rshift64(lhsLocation.asGPR(), TrustedImm32(shiftAmount), resultLocation.asGPR());
} else {
if constexpr (is32)
m_jit.urshift32(lhsLocation.asGPR(), m_jit.trustedImm32ForShift(Imm32(shiftAmount)), resultLocation.asGPR());
else
m_jit.urshift64(lhsLocation.asGPR(), TrustedImm32(shiftAmount), resultLocation.asGPR());
}
if constexpr (isSigned) {
if (divisorIsNegative) {
if constexpr (is32)
m_jit.neg32(resultLocation.asGPR(), resultLocation.asGPR());
else
m_jit.neg64(resultLocation.asGPR(), resultLocation.asGPR());
}
}
return;
}
}
// TODO: try generating integer reciprocal instead.
checkedForNegativeOne = true;
checkedForZero = true;
rhsLocation = Location::fromGPR(wasmScratchGPR);
emitMoveConst(rhs, rhsLocation);
// Fall through to register/register div.
} else if (lhs.isConst()) {
int64_t dividend = is32 ? lhs.asI32() : lhs.asI64();
Jump isZero = is32
? m_jit.branchTest32(ResultCondition::Zero, rhsLocation.asGPR())
: m_jit.branchTest64(ResultCondition::Zero, rhsLocation.asGPR());
recordJumpToThrowException(ExceptionType::DivisionByZero, isZero);
checkedForZero = true;
if (!dividend) {
if constexpr (is32)
m_jit.xor32(resultLocation.asGPR(), resultLocation.asGPR());
else
m_jit.xor64(resultLocation.asGPR(), resultLocation.asGPR());
return;
}
if (isSigned && !IsMod && dividend == std::numeric_limits<IntType>::min()) {
Jump isNegativeOne = is32
? m_jit.branch32(RelationalCondition::Equal, rhsLocation.asGPR(), TrustedImm32(-1))
: m_jit.branch64(RelationalCondition::Equal, rhsLocation.asGPR(), TrustedImm64(-1));
recordJumpToThrowException(ExceptionType::IntegerOverflow, isNegativeOne);
}
checkedForNegativeOne = true;
lhsLocation = Location::fromGPR(wasmScratchGPR);
emitMoveConst(lhs, lhsLocation);
// Fall through to register/register div.
}
if (!checkedForZero) {
Jump isZero = is32
? m_jit.branchTest32(ResultCondition::Zero, rhsLocation.asGPR())
: m_jit.branchTest64(ResultCondition::Zero, rhsLocation.asGPR());
recordJumpToThrowException(ExceptionType::DivisionByZero, isZero);
}
ScratchScope<1, 0> scratches(*this, lhsLocation, rhsLocation, resultLocation);
if (isSigned && !IsMod && !checkedForNegativeOne) {
// The following code freely clobbers wasmScratchGPR. This would be a bug if either of our operands were
// stored in wasmScratchGPR, which is the case if one of our operands is a constant - but in that case,
// we should be able to rule out this check based on the value of that constant above.
ASSERT(!lhs.isConst());
ASSERT(!rhs.isConst());
ASSERT(lhsLocation.asGPR() != wasmScratchGPR);
ASSERT(rhsLocation.asGPR() != wasmScratchGPR);
if constexpr (is32)
m_jit.compare32(RelationalCondition::Equal, rhsLocation.asGPR(), TrustedImm32(-1), wasmScratchGPR);
else
m_jit.compare64(RelationalCondition::Equal, rhsLocation.asGPR(), TrustedImm32(-1), wasmScratchGPR);
if constexpr (is32)
m_jit.compare32(RelationalCondition::Equal, lhsLocation.asGPR(), TrustedImm32(std::numeric_limits<int32_t>::min()), scratches.gpr(0));
else {
m_jit.move(TrustedImm64(std::numeric_limits<int64_t>::min()), scratches.gpr(0));
m_jit.compare64(RelationalCondition::Equal, lhsLocation.asGPR(), scratches.gpr(0), scratches.gpr(0));
}
m_jit.and64(wasmScratchGPR, scratches.gpr(0), wasmScratchGPR);
Jump isNegativeOne = m_jit.branchTest64(ResultCondition::NonZero, wasmScratchGPR);
recordJumpToThrowException(ExceptionType::IntegerOverflow, isNegativeOne);
}
GPRReg divResult = IsMod ? scratches.gpr(0) : resultLocation.asGPR();
if (is32 && isSigned)
m_jit.div32(lhsLocation.asGPR(), rhsLocation.asGPR(), divResult);
else if (is32)
m_jit.uDiv32(lhsLocation.asGPR(), rhsLocation.asGPR(), divResult);
else if (isSigned)
m_jit.div64(lhsLocation.asGPR(), rhsLocation.asGPR(), divResult);
else
m_jit.uDiv64(lhsLocation.asGPR(), rhsLocation.asGPR(), divResult);
if (IsMod) {
if (is32)
m_jit.multiplySub32(divResult, rhsLocation.asGPR(), lhsLocation.asGPR(), resultLocation.asGPR());
else
m_jit.multiplySub64(divResult, rhsLocation.asGPR(), lhsLocation.asGPR(), resultLocation.asGPR());
}
}
#endif
#if CPU(X86_64)
#define PREPARE_FOR_SHIFT \
do { \
clobber(shiftRCX); \
} while (false); \
ScratchScope<0, 0> scratches(*this, Location::fromGPR(shiftRCX))
#else
#define PREPARE_FOR_SHIFT
#endif
template<size_t N, typename OverflowHandler>
void BBQJIT::emitShuffleMove(Vector<Value, N, OverflowHandler>& srcVector, Vector<Location, N, OverflowHandler>& dstVector, Vector<ShuffleStatus, N, OverflowHandler>& statusVector, unsigned index)
{
Location srcLocation = locationOf(srcVector[index]);
Location dst = dstVector[index];
if (srcLocation == dst)
return; // Easily eliminate redundant moves here.
uint32_t dstSize = srcVector[index].size();
statusVector[index] = ShuffleStatus::BeingMoved;
for (unsigned i = 0; i < srcVector.size(); i ++) {
// This check should handle constants too - constants always have location None, and no
// dst should ever be a constant. But we assume that's asserted in the caller.
if (Location::rangesOverlap(locationOf(srcVector[i]), srcVector[i].size(), dst, dstSize)) {
switch (statusVector[i]) {
case ShuffleStatus::ToMove:
emitShuffleMove(srcVector, dstVector, statusVector, i);
break;
case ShuffleStatus::BeingMoved: {
Location temp = srcVector[i].isFloat() ? Location::fromFPR(wasmScratchFPR) : Location::fromGPR(wasmScratchGPR);
emitMove(srcVector[i], temp);
srcVector[i] = Value::pinned(srcVector[i].type(), temp);
break;
}
case ShuffleStatus::Moved:
break;
}
}
}
emitMove(srcVector[index], dst);
statusVector[index] = ShuffleStatus::Moved;
}
template<typename Func>
void BBQJIT::emitCCall(Func function, std::span<const Value> arguments)
{
// Currently, we assume the Wasm calling convention is the same as the C calling convention
Vector<Type, 16> resultTypes;
auto argumentTypes = WTF::map<16>(arguments, [](auto& value) {
return Type { value.type(), 0u };
});
Ref<const RTT> functionRTT = TypeInformation::rttForFunction(resultTypes, argumentTypes);
CallInformation callInfo = wasmCallingConvention().callInformationFor(functionRTT.get(), CallRole::Caller);
Checked<int32_t> calleeStackSize = WTF::roundUpToMultipleOf<stackAlignmentBytes()>(callInfo.headerAndArgumentStackSizeInBytes);
m_maxCalleeStackSizeForValidation = std::max<uint32_t>(calleeStackSize, m_maxCalleeStackSizeForValidation);
ASSERT(static_cast<uint32_t>(alignedFrameSize(m_maxCalleeStackSizeForValidation + m_frameSizeForValidation)) <= m_frameSize);
// Prepare wasm operation calls.
m_jit.prepareWasmCallOperation(GPRInfo::wasmContextInstancePointer);
// Preserve caller-saved registers and other info
prepareForExceptions();
saveValuesAcrossCallAndPassArguments(arguments, callInfo, functionRTT.get());
// Materialize address of native function and call register
void* taggedFunctionPtr = tagCFunctionPtr<void*, OperationPtrTag>(function);
m_jit.move(TrustedImmPtr(std::bit_cast<uintptr_t>(taggedFunctionPtr)), wasmScratchGPR);
m_jit.call(wasmScratchGPR, OperationPtrTag);
}
template<typename Func>
void BBQJIT::emitCCall(Func function, std::span<const Value> arguments, Value& result)
{
ASSERT(result.isTemp());
// Currently, we assume the Wasm calling convention is the same as the C calling convention
Vector<Type, 16> resultTypes = { Type { result.type(), 0u } };
auto argumentTypes = WTF::map<16>(arguments, [](auto& value) {
return Type { value.type(), 0u };
});
Ref<const RTT> functionRTT = TypeInformation::rttForFunction(resultTypes, argumentTypes);
CallInformation callInfo = wasmCallingConvention().callInformationFor(functionRTT.get(), CallRole::Caller);
Checked<int32_t> calleeStackSize = WTF::roundUpToMultipleOf<stackAlignmentBytes()>(callInfo.headerAndArgumentStackSizeInBytes);
m_maxCalleeStackSizeForValidation = std::max<uint32_t>(calleeStackSize, m_maxCalleeStackSizeForValidation);
ASSERT(static_cast<uint32_t>(alignedFrameSize(m_maxCalleeStackSizeForValidation + m_frameSizeForValidation)) <= m_frameSize);
// Prepare wasm operation calls.
m_jit.prepareWasmCallOperation(GPRInfo::wasmContextInstancePointer);
// Preserve caller-saved registers and other info
prepareForExceptions();
saveValuesAcrossCallAndPassArguments(arguments, callInfo, functionRTT.get());
// Materialize address of native function and call register
void* taggedFunctionPtr = tagCFunctionPtr<void*, OperationPtrTag>(function);
m_jit.move(TrustedImmPtr(std::bit_cast<uintptr_t>(taggedFunctionPtr)), wasmScratchGPR);
m_jit.call(wasmScratchGPR, OperationPtrTag);
Location resultLocation;
switch (result.type()) {
case TypeKind::I32:
case TypeKind::I31ref:
case TypeKind::I64:
case TypeKind::Ref:
case TypeKind::RefNull:
case TypeKind::Arrayref:
case TypeKind::Structref:
case TypeKind::Funcref:
case TypeKind::Exnref:
case TypeKind::Externref:
case TypeKind::Eqref:
case TypeKind::Anyref:
case TypeKind::Noexnref:
case TypeKind::Noneref:
case TypeKind::Nofuncref:
case TypeKind::Noexternref: {
resultLocation = Location::fromGPR(GPRInfo::returnValueGPR);
ASSERT(validGPRs().contains(GPRInfo::returnValueGPR, IgnoreVectors));
break;
}
case TypeKind::F32:
case TypeKind::F64: {
resultLocation = Location::fromFPR(FPRInfo::returnValueFPR);
ASSERT(validFPRs().contains(FPRInfo::returnValueFPR, Width::Width128));
break;
}
case TypeKind::V128: {
resultLocation = Location::fromFPR(FPRInfo::returnValueFPR);
ASSERT(validFPRs().contains(FPRInfo::returnValueFPR, Width::Width128));
break;
}
case TypeKind::Void:
RELEASE_ASSERT_NOT_REACHED();
break;
}
RegisterBinding currentBinding;
if (resultLocation.isGPR())
currentBinding = bindingFor(resultLocation.asGPR());
else if (resultLocation.isFPR())
currentBinding = bindingFor(resultLocation.asFPR());
RELEASE_ASSERT(!currentBinding.isScratch());
bind(result, resultLocation);
}
} } } // namespace JSC::Wasm::BBQJITImpl
#endif // ENABLE(WEBASSEMBLY_BBQJIT)