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Diffstat (limited to 'js/src/jit/shared/CodeGenerator-shared.cpp')
| -rw-r--r-- | js/src/jit/shared/CodeGenerator-shared.cpp | 1204 |
1 files changed, 1204 insertions, 0 deletions
diff --git a/js/src/jit/shared/CodeGenerator-shared.cpp b/js/src/jit/shared/CodeGenerator-shared.cpp new file mode 100644 index 0000000000..12e48dfd56 --- /dev/null +++ b/js/src/jit/shared/CodeGenerator-shared.cpp @@ -0,0 +1,1204 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- + * vim: set ts=8 sts=2 et sw=2 tw=80: + * This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +#include "jit/shared/CodeGenerator-shared-inl.h" + +#include "mozilla/DebugOnly.h" + +#include <utility> + +#include "jit/CodeGenerator.h" +#include "jit/CompactBuffer.h" +#include "jit/CompileInfo.h" +#include "jit/InlineScriptTree.h" +#include "jit/JitcodeMap.h" +#include "jit/JitFrames.h" +#include "jit/JitSpewer.h" +#include "jit/MacroAssembler.h" +#include "jit/MIR.h" +#include "jit/MIRGenerator.h" +#include "jit/SafepointIndex.h" +#include "js/Conversions.h" +#include "util/Memory.h" +#include "vm/TraceLogging.h" + +#include "jit/MacroAssembler-inl.h" +#include "vm/JSScript-inl.h" + +using namespace js; +using namespace js::jit; + +using mozilla::BitwiseCast; +using mozilla::DebugOnly; + +namespace js { +namespace jit { + +MacroAssembler& CodeGeneratorShared::ensureMasm(MacroAssembler* masmArg) { + if (masmArg) { + return *masmArg; + } + maybeMasm_.emplace(); + return *maybeMasm_; +} + +CodeGeneratorShared::CodeGeneratorShared(MIRGenerator* gen, LIRGraph* graph, + MacroAssembler* masmArg) + : maybeMasm_(), + useWasmStackArgumentAbi_(false), + masm(ensureMasm(masmArg)), + gen(gen), + graph(*graph), + current(nullptr), + snapshots_(), + recovers_(), + deoptTable_(), +#ifdef DEBUG + pushedArgs_(0), +#endif + lastOsiPointOffset_(0), + safepoints_(graph->totalSlotCount(), + (gen->outerInfo().nargs() + 1) * sizeof(Value)), + returnLabel_(), + nativeToBytecodeMap_(nullptr), + nativeToBytecodeMapSize_(0), + nativeToBytecodeTableOffset_(0), + nativeToBytecodeNumRegions_(0), + nativeToBytecodeScriptList_(nullptr), + nativeToBytecodeScriptListLength_(0), +#ifdef CHECK_OSIPOINT_REGISTERS + checkOsiPointRegisters(JitOptions.checkOsiPointRegisters), +#endif + frameDepth_(graph->paddedLocalSlotsSize() + graph->argumentsSize()), + frameClass_(FrameSizeClass::None()) { + if (gen->isProfilerInstrumentationEnabled()) { + masm.enableProfilingInstrumentation(); + } + + if (gen->compilingWasm()) { + // Since wasm uses the system ABI which does not necessarily use a + // regular array where all slots are sizeof(Value), it maintains the max + // argument stack depth separately. + MOZ_ASSERT(graph->argumentSlotCount() == 0); + frameDepth_ += gen->wasmMaxStackArgBytes(); + +#ifdef ENABLE_WASM_SIMD +# if defined(JS_CODEGEN_X64) || defined(JS_CODEGEN_X86) || \ + defined(JS_CODEGEN_ARM64) + // On X64/x86 and ARM64, we don't need alignment for Wasm SIMD at this time. +# else +# error \ + "we may need padding so that local slots are SIMD-aligned and the stack must be kept SIMD-aligned too." +# endif +#endif + + if (gen->needsStaticStackAlignment()) { + // An MWasmCall does not align the stack pointer at calls sites but + // instead relies on the a priori stack adjustment. This must be the + // last adjustment of frameDepth_. + frameDepth_ += ComputeByteAlignment(sizeof(wasm::Frame) + frameDepth_, + WasmStackAlignment); + } + + // FrameSizeClass is only used for bailing, which cannot happen in + // wasm code. + MOZ_ASSERT(frameClass_ == FrameSizeClass::None()); + } else { + frameClass_ = FrameSizeClass::FromDepth(frameDepth_); + } +} + +bool CodeGeneratorShared::generatePrologue() { + MOZ_ASSERT(masm.framePushed() == 0); + MOZ_ASSERT(!gen->compilingWasm()); + +#ifdef JS_USE_LINK_REGISTER + masm.pushReturnAddress(); +#endif + + // If profiling, save the current frame pointer to a per-thread global field. + if (isProfilerInstrumentationEnabled()) { + masm.profilerEnterFrame(masm.getStackPointer(), CallTempReg0); + } + + // Ensure that the Ion frame is properly aligned. + masm.assertStackAlignment(JitStackAlignment, 0); + + // Note that this automatically sets MacroAssembler::framePushed(). + masm.reserveStack(frameSize()); + masm.checkStackAlignment(); + + if (JS::TraceLoggerSupported()) { + emitTracelogIonStart(); + } + + return true; +} + +bool CodeGeneratorShared::generateEpilogue() { + MOZ_ASSERT(!gen->compilingWasm()); + masm.bind(&returnLabel_); + + if (JS::TraceLoggerSupported()) { + emitTracelogIonStop(); + } + + masm.freeStack(frameSize()); + MOZ_ASSERT(masm.framePushed() == 0); + + // If profiling, reset the per-thread global lastJitFrame to point to + // the previous frame. + if (isProfilerInstrumentationEnabled()) { + masm.profilerExitFrame(); + } + + masm.ret(); + + // On systems that use a constant pool, this is a good time to emit. + masm.flushBuffer(); + return true; +} + +bool CodeGeneratorShared::generateOutOfLineCode() { + // OOL paths should not attempt to use |current| as it's the last block + // instead of the block corresponding to the OOL path. + current = nullptr; + + for (size_t i = 0; i < outOfLineCode_.length(); i++) { + // Add native => bytecode mapping entries for OOL sites. + // Not enabled on wasm yet since it doesn't contain bytecode mappings. + if (!gen->compilingWasm()) { + if (!addNativeToBytecodeEntry(outOfLineCode_[i]->bytecodeSite())) { + return false; + } + } + + if (!gen->alloc().ensureBallast()) { + return false; + } + + JitSpew(JitSpew_Codegen, "# Emitting out of line code"); + + masm.setFramePushed(outOfLineCode_[i]->framePushed()); + lastPC_ = outOfLineCode_[i]->pc(); + outOfLineCode_[i]->bind(&masm); + + outOfLineCode_[i]->generate(this); + } + + return !masm.oom(); +} + +void CodeGeneratorShared::addOutOfLineCode(OutOfLineCode* code, + const MInstruction* mir) { + MOZ_ASSERT(mir); + addOutOfLineCode(code, mir->trackedSite()); +} + +void CodeGeneratorShared::addOutOfLineCode(OutOfLineCode* code, + const BytecodeSite* site) { + code->setFramePushed(masm.framePushed()); + code->setBytecodeSite(site); + MOZ_ASSERT_IF(!gen->compilingWasm(), code->script()->containsPC(code->pc())); + masm.propagateOOM(outOfLineCode_.append(code)); +} + +bool CodeGeneratorShared::addNativeToBytecodeEntry(const BytecodeSite* site) { + // Skip the table entirely if profiling is not enabled. + if (!isProfilerInstrumentationEnabled()) { + return true; + } + + // Fails early if the last added instruction caused the macro assembler to + // run out of memory as continuity assumption below do not hold. + if (masm.oom()) { + return false; + } + + MOZ_ASSERT(site); + MOZ_ASSERT(site->tree()); + MOZ_ASSERT(site->pc()); + + InlineScriptTree* tree = site->tree(); + jsbytecode* pc = site->pc(); + uint32_t nativeOffset = masm.currentOffset(); + + MOZ_ASSERT_IF(nativeToBytecodeList_.empty(), nativeOffset == 0); + + if (!nativeToBytecodeList_.empty()) { + size_t lastIdx = nativeToBytecodeList_.length() - 1; + NativeToBytecode& lastEntry = nativeToBytecodeList_[lastIdx]; + + MOZ_ASSERT(nativeOffset >= lastEntry.nativeOffset.offset()); + + // If the new entry is for the same inlineScriptTree and same + // bytecodeOffset, but the nativeOffset has changed, do nothing. + // The same site just generated some more code. + if (lastEntry.tree == tree && lastEntry.pc == pc) { + JitSpew(JitSpew_Profiling, " => In-place update [%zu-%" PRIu32 "]", + lastEntry.nativeOffset.offset(), nativeOffset); + return true; + } + + // If the new entry is for the same native offset, then update the + // previous entry with the new bytecode site, since the previous + // bytecode site did not generate any native code. + if (lastEntry.nativeOffset.offset() == nativeOffset) { + lastEntry.tree = tree; + lastEntry.pc = pc; + JitSpew(JitSpew_Profiling, " => Overwriting zero-length native region."); + + // This overwrite might have made the entry merge-able with a + // previous one. If so, merge it. + if (lastIdx > 0) { + NativeToBytecode& nextToLastEntry = nativeToBytecodeList_[lastIdx - 1]; + if (nextToLastEntry.tree == lastEntry.tree && + nextToLastEntry.pc == lastEntry.pc) { + JitSpew(JitSpew_Profiling, " => Merging with previous region"); + nativeToBytecodeList_.erase(&lastEntry); + } + } + + dumpNativeToBytecodeEntry(nativeToBytecodeList_.length() - 1); + return true; + } + } + + // Otherwise, some native code was generated for the previous bytecode site. + // Add a new entry for code that is about to be generated. + NativeToBytecode entry; + entry.nativeOffset = CodeOffset(nativeOffset); + entry.tree = tree; + entry.pc = pc; + if (!nativeToBytecodeList_.append(entry)) { + return false; + } + + JitSpew(JitSpew_Profiling, " => Push new entry."); + dumpNativeToBytecodeEntry(nativeToBytecodeList_.length() - 1); + return true; +} + +void CodeGeneratorShared::dumpNativeToBytecodeEntries() { +#ifdef JS_JITSPEW + InlineScriptTree* topTree = gen->outerInfo().inlineScriptTree(); + JitSpewStart(JitSpew_Profiling, "Native To Bytecode Entries for %s:%u:%u\n", + topTree->script()->filename(), topTree->script()->lineno(), + topTree->script()->column()); + for (unsigned i = 0; i < nativeToBytecodeList_.length(); i++) { + dumpNativeToBytecodeEntry(i); + } +#endif +} + +void CodeGeneratorShared::dumpNativeToBytecodeEntry(uint32_t idx) { +#ifdef JS_JITSPEW + NativeToBytecode& ref = nativeToBytecodeList_[idx]; + InlineScriptTree* tree = ref.tree; + JSScript* script = tree->script(); + uint32_t nativeOffset = ref.nativeOffset.offset(); + unsigned nativeDelta = 0; + unsigned pcDelta = 0; + if (idx + 1 < nativeToBytecodeList_.length()) { + NativeToBytecode* nextRef = &ref + 1; + nativeDelta = nextRef->nativeOffset.offset() - nativeOffset; + if (nextRef->tree == ref.tree) { + pcDelta = nextRef->pc - ref.pc; + } + } + JitSpewStart( + JitSpew_Profiling, " %08zx [+%-6u] => %-6ld [%-4u] {%-10s} (%s:%u:%u", + ref.nativeOffset.offset(), nativeDelta, (long)(ref.pc - script->code()), + pcDelta, CodeName(JSOp(*ref.pc)), script->filename(), script->lineno(), + script->column()); + + for (tree = tree->caller(); tree; tree = tree->caller()) { + JitSpewCont(JitSpew_Profiling, " <= %s:%u:%u", tree->script()->filename(), + tree->script()->lineno(), tree->script()->column()); + } + JitSpewCont(JitSpew_Profiling, ")"); + JitSpewFin(JitSpew_Profiling); +#endif +} + +// see OffsetOfFrameSlot +static inline int32_t ToStackIndex(LAllocation* a) { + if (a->isStackSlot()) { + MOZ_ASSERT(a->toStackSlot()->slot() >= 1); + return a->toStackSlot()->slot(); + } + return -int32_t(sizeof(JitFrameLayout) + a->toArgument()->index()); +} + +void CodeGeneratorShared::encodeAllocation(LSnapshot* snapshot, + MDefinition* mir, + uint32_t* allocIndex) { + if (mir->isBox()) { + mir = mir->toBox()->getOperand(0); + } + + MIRType type = mir->isRecoveredOnBailout() ? MIRType::None + : mir->isUnused() ? MIRType::MagicOptimizedOut + : mir->type(); + + RValueAllocation alloc; + + switch (type) { + case MIRType::None: { + MOZ_ASSERT(mir->isRecoveredOnBailout()); + uint32_t index = 0; + LRecoverInfo* recoverInfo = snapshot->recoverInfo(); + MNode** it = recoverInfo->begin(); + MNode** end = recoverInfo->end(); + while (it != end && mir != *it) { + ++it; + ++index; + } + + // This MDefinition is recovered, thus it should be listed in the + // LRecoverInfo. + MOZ_ASSERT(it != end && mir == *it); + + // Lambda should have a default value readable for iterating over the + // inner frames. + MConstant* functionOperand = nullptr; + if (mir->isLambda()) { + functionOperand = mir->toLambda()->functionOperand(); + } else if (mir->isLambdaArrow()) { + functionOperand = mir->toLambdaArrow()->functionOperand(); + } else if (mir->isFunctionWithProto()) { + functionOperand = mir->toFunctionWithProto()->functionOperand(); + } + if (functionOperand) { + uint32_t cstIndex; + masm.propagateOOM( + graph.addConstantToPool(functionOperand->toJSValue(), &cstIndex)); + alloc = RValueAllocation::RecoverInstruction(index, cstIndex); + break; + } + + alloc = RValueAllocation::RecoverInstruction(index); + break; + } + case MIRType::Undefined: + alloc = RValueAllocation::Undefined(); + break; + case MIRType::Null: + alloc = RValueAllocation::Null(); + break; + case MIRType::Int32: + case MIRType::String: + case MIRType::Symbol: + case MIRType::BigInt: + case MIRType::Object: + case MIRType::Boolean: + case MIRType::Double: { + LAllocation* payload = snapshot->payloadOfSlot(*allocIndex); + if (payload->isConstant()) { + MConstant* constant = mir->toConstant(); + uint32_t index; + masm.propagateOOM( + graph.addConstantToPool(constant->toJSValue(), &index)); + alloc = RValueAllocation::ConstantPool(index); + break; + } + + JSValueType valueType = ValueTypeFromMIRType(type); + + MOZ_DIAGNOSTIC_ASSERT(payload->isMemory() || payload->isRegister()); + if (payload->isMemory()) { + alloc = RValueAllocation::Typed(valueType, ToStackIndex(payload)); + } else if (payload->isGeneralReg()) { + alloc = RValueAllocation::Typed(valueType, ToRegister(payload)); + } else if (payload->isFloatReg()) { + alloc = RValueAllocation::Double(ToFloatRegister(payload)); + } else { + MOZ_CRASH("Unexpected payload type."); + } + break; + } + case MIRType::Float32: + case MIRType::Simd128: { + LAllocation* payload = snapshot->payloadOfSlot(*allocIndex); + if (payload->isConstant()) { + MConstant* constant = mir->toConstant(); + uint32_t index; + masm.propagateOOM( + graph.addConstantToPool(constant->toJSValue(), &index)); + alloc = RValueAllocation::ConstantPool(index); + break; + } + + MOZ_ASSERT(payload->isMemory() || payload->isFloatReg()); + if (payload->isFloatReg()) { + alloc = RValueAllocation::AnyFloat(ToFloatRegister(payload)); + } else { + alloc = RValueAllocation::AnyFloat(ToStackIndex(payload)); + } + break; + } + case MIRType::MagicOptimizedArguments: + case MIRType::MagicOptimizedOut: + case MIRType::MagicUninitializedLexical: + case MIRType::MagicIsConstructing: { + uint32_t index; + JSWhyMagic why = JS_GENERIC_MAGIC; + switch (type) { + case MIRType::MagicOptimizedArguments: + why = JS_OPTIMIZED_ARGUMENTS; + break; + case MIRType::MagicOptimizedOut: + why = JS_OPTIMIZED_OUT; + break; + case MIRType::MagicUninitializedLexical: + why = JS_UNINITIALIZED_LEXICAL; + break; + case MIRType::MagicIsConstructing: + why = JS_IS_CONSTRUCTING; + break; + default: + MOZ_CRASH("Invalid Magic MIRType"); + } + + Value v = MagicValue(why); + masm.propagateOOM(graph.addConstantToPool(v, &index)); + alloc = RValueAllocation::ConstantPool(index); + break; + } + default: { + MOZ_ASSERT(mir->type() == MIRType::Value); + LAllocation* payload = snapshot->payloadOfSlot(*allocIndex); +#ifdef JS_NUNBOX32 + LAllocation* type = snapshot->typeOfSlot(*allocIndex); + if (type->isRegister()) { + if (payload->isRegister()) { + alloc = + RValueAllocation::Untyped(ToRegister(type), ToRegister(payload)); + } else { + alloc = RValueAllocation::Untyped(ToRegister(type), + ToStackIndex(payload)); + } + } else { + if (payload->isRegister()) { + alloc = RValueAllocation::Untyped(ToStackIndex(type), + ToRegister(payload)); + } else { + alloc = RValueAllocation::Untyped(ToStackIndex(type), + ToStackIndex(payload)); + } + } +#elif JS_PUNBOX64 + if (payload->isRegister()) { + alloc = RValueAllocation::Untyped(ToRegister(payload)); + } else { + alloc = RValueAllocation::Untyped(ToStackIndex(payload)); + } +#endif + break; + } + } + MOZ_DIAGNOSTIC_ASSERT(alloc.valid()); + + // This set an extra bit as part of the RValueAllocation, such that we know + // that recover instruction have to be executed without wrapping the + // instruction in a no-op recover instruction. + if (mir->isIncompleteObject()) { + alloc.setNeedSideEffect(); + } + + masm.propagateOOM(snapshots_.add(alloc)); + + *allocIndex += mir->isRecoveredOnBailout() ? 0 : 1; +} + +void CodeGeneratorShared::encode(LRecoverInfo* recover) { + if (recover->recoverOffset() != INVALID_RECOVER_OFFSET) { + return; + } + + uint32_t numInstructions = recover->numInstructions(); + JitSpew(JitSpew_IonSnapshots, + "Encoding LRecoverInfo %p (frameCount %u, instructions %u)", + (void*)recover, recover->mir()->frameCount(), numInstructions); + + MResumePoint::Mode mode = recover->mir()->mode(); + MOZ_ASSERT(mode != MResumePoint::Outer); + bool resumeAfter = (mode == MResumePoint::ResumeAfter); + + RecoverOffset offset = recovers_.startRecover(numInstructions, resumeAfter); + + for (MNode* insn : *recover) { + recovers_.writeInstruction(insn); + } + + recovers_.endRecover(); + recover->setRecoverOffset(offset); + masm.propagateOOM(!recovers_.oom()); +} + +void CodeGeneratorShared::encode(LSnapshot* snapshot) { + if (snapshot->snapshotOffset() != INVALID_SNAPSHOT_OFFSET) { + return; + } + + LRecoverInfo* recoverInfo = snapshot->recoverInfo(); + encode(recoverInfo); + + RecoverOffset recoverOffset = recoverInfo->recoverOffset(); + MOZ_ASSERT(recoverOffset != INVALID_RECOVER_OFFSET); + + JitSpew(JitSpew_IonSnapshots, "Encoding LSnapshot %p (LRecover %p)", + (void*)snapshot, (void*)recoverInfo); + + SnapshotOffset offset = + snapshots_.startSnapshot(recoverOffset, snapshot->bailoutKind()); + +#ifdef TRACK_SNAPSHOTS + uint32_t pcOpcode = 0; + uint32_t lirOpcode = 0; + uint32_t lirId = 0; + uint32_t mirOpcode = 0; + uint32_t mirId = 0; + + if (LNode* ins = instruction()) { + lirOpcode = uint32_t(ins->op()); + lirId = ins->id(); + if (ins->mirRaw()) { + mirOpcode = uint32_t(ins->mirRaw()->op()); + mirId = ins->mirRaw()->id(); + if (ins->mirRaw()->trackedPc()) { + pcOpcode = *ins->mirRaw()->trackedPc(); + } + } + } + snapshots_.trackSnapshot(pcOpcode, mirOpcode, mirId, lirOpcode, lirId); +#endif + + uint32_t allocIndex = 0; + for (LRecoverInfo::OperandIter it(recoverInfo); !it; ++it) { + DebugOnly<uint32_t> allocWritten = snapshots_.allocWritten(); + encodeAllocation(snapshot, *it, &allocIndex); + MOZ_ASSERT_IF(!snapshots_.oom(), + allocWritten + 1 == snapshots_.allocWritten()); + } + + MOZ_ASSERT(allocIndex == snapshot->numSlots()); + snapshots_.endSnapshot(); + snapshot->setSnapshotOffset(offset); + masm.propagateOOM(!snapshots_.oom()); +} + +bool CodeGeneratorShared::assignBailoutId(LSnapshot* snapshot) { + MOZ_ASSERT(snapshot->snapshotOffset() != INVALID_SNAPSHOT_OFFSET); + + // Can we not use bailout tables at all? + if (!deoptTable_) { + return false; + } + + MOZ_ASSERT(frameClass_ != FrameSizeClass::None()); + + if (snapshot->bailoutId() != INVALID_BAILOUT_ID) { + return true; + } + + // Is the bailout table full? + if (bailouts_.length() >= BAILOUT_TABLE_SIZE) { + return false; + } + + unsigned bailoutId = bailouts_.length(); + snapshot->setBailoutId(bailoutId); + JitSpew(JitSpew_IonSnapshots, "Assigned snapshot bailout id %u", bailoutId); + masm.propagateOOM(bailouts_.append(snapshot->snapshotOffset())); + return true; +} + +bool CodeGeneratorShared::encodeSafepoints() { + for (CodegenSafepointIndex& index : safepointIndices_) { + LSafepoint* safepoint = index.safepoint(); + + if (!safepoint->encoded()) { + safepoints_.encode(safepoint); + } + } + + return !safepoints_.oom(); +} + +bool CodeGeneratorShared::createNativeToBytecodeScriptList(JSContext* cx) { + js::Vector<JSScript*, 0, SystemAllocPolicy> scriptList; + InlineScriptTree* tree = gen->outerInfo().inlineScriptTree(); + for (;;) { + // Add script from current tree. + bool found = false; + for (uint32_t i = 0; i < scriptList.length(); i++) { + if (scriptList[i] == tree->script()) { + found = true; + break; + } + } + if (!found) { + if (!scriptList.append(tree->script())) { + return false; + } + } + + // Process rest of tree + + // If children exist, emit children. + if (tree->hasChildren()) { + tree = tree->firstChild(); + continue; + } + + // Otherwise, find the first tree up the chain (including this one) + // that contains a next sibling. + while (!tree->hasNextCallee() && tree->hasCaller()) { + tree = tree->caller(); + } + + // If we found a sibling, use it. + if (tree->hasNextCallee()) { + tree = tree->nextCallee(); + continue; + } + + // Otherwise, we must have reached the top without finding any siblings. + MOZ_ASSERT(tree->isOutermostCaller()); + break; + } + + // Allocate array for list. + JSScript** data = cx->pod_malloc<JSScript*>(scriptList.length()); + if (!data) { + return false; + } + + for (uint32_t i = 0; i < scriptList.length(); i++) { + data[i] = scriptList[i]; + } + + // Success. + nativeToBytecodeScriptListLength_ = scriptList.length(); + nativeToBytecodeScriptList_ = data; + return true; +} + +bool CodeGeneratorShared::generateCompactNativeToBytecodeMap(JSContext* cx, + JitCode* code) { + MOZ_ASSERT(nativeToBytecodeScriptListLength_ == 0); + MOZ_ASSERT(nativeToBytecodeScriptList_ == nullptr); + MOZ_ASSERT(nativeToBytecodeMap_ == nullptr); + MOZ_ASSERT(nativeToBytecodeMapSize_ == 0); + MOZ_ASSERT(nativeToBytecodeTableOffset_ == 0); + MOZ_ASSERT(nativeToBytecodeNumRegions_ == 0); + + if (!createNativeToBytecodeScriptList(cx)) { + return false; + } + + MOZ_ASSERT(nativeToBytecodeScriptListLength_ > 0); + MOZ_ASSERT(nativeToBytecodeScriptList_ != nullptr); + + CompactBufferWriter writer; + uint32_t tableOffset = 0; + uint32_t numRegions = 0; + + if (!JitcodeIonTable::WriteIonTable( + writer, nativeToBytecodeScriptList_, + nativeToBytecodeScriptListLength_, &nativeToBytecodeList_[0], + &nativeToBytecodeList_[0] + nativeToBytecodeList_.length(), + &tableOffset, &numRegions)) { + js_free(nativeToBytecodeScriptList_); + return false; + } + + MOZ_ASSERT(tableOffset > 0); + MOZ_ASSERT(numRegions > 0); + + // Writer is done, copy it to sized buffer. + uint8_t* data = cx->pod_malloc<uint8_t>(writer.length()); + if (!data) { + js_free(nativeToBytecodeScriptList_); + return false; + } + + memcpy(data, writer.buffer(), writer.length()); + nativeToBytecodeMap_ = data; + nativeToBytecodeMapSize_ = writer.length(); + nativeToBytecodeTableOffset_ = tableOffset; + nativeToBytecodeNumRegions_ = numRegions; + + verifyCompactNativeToBytecodeMap(code); + + JitSpew(JitSpew_Profiling, "Compact Native To Bytecode Map [%p-%p]", data, + data + nativeToBytecodeMapSize_); + + return true; +} + +void CodeGeneratorShared::verifyCompactNativeToBytecodeMap(JitCode* code) { +#ifdef DEBUG + MOZ_ASSERT(nativeToBytecodeScriptListLength_ > 0); + MOZ_ASSERT(nativeToBytecodeScriptList_ != nullptr); + MOZ_ASSERT(nativeToBytecodeMap_ != nullptr); + MOZ_ASSERT(nativeToBytecodeMapSize_ > 0); + MOZ_ASSERT(nativeToBytecodeTableOffset_ > 0); + MOZ_ASSERT(nativeToBytecodeNumRegions_ > 0); + + // The pointer to the table must be 4-byte aligned + const uint8_t* tablePtr = nativeToBytecodeMap_ + nativeToBytecodeTableOffset_; + MOZ_ASSERT(uintptr_t(tablePtr) % sizeof(uint32_t) == 0); + + // Verify that numRegions was encoded correctly. + const JitcodeIonTable* ionTable = + reinterpret_cast<const JitcodeIonTable*>(tablePtr); + MOZ_ASSERT(ionTable->numRegions() == nativeToBytecodeNumRegions_); + + // Region offset for first region should be at the start of the payload + // region. Since the offsets are backward from the start of the table, the + // first entry backoffset should be equal to the forward table offset from the + // start of the allocated data. + MOZ_ASSERT(ionTable->regionOffset(0) == nativeToBytecodeTableOffset_); + + // Verify each region. + for (uint32_t i = 0; i < ionTable->numRegions(); i++) { + // Back-offset must point into the payload region preceding the table, not + // before it. + MOZ_ASSERT(ionTable->regionOffset(i) <= nativeToBytecodeTableOffset_); + + // Back-offset must point to a later area in the payload region than + // previous back-offset. This means that back-offsets decrease + // monotonically. + MOZ_ASSERT_IF(i > 0, + ionTable->regionOffset(i) < ionTable->regionOffset(i - 1)); + + JitcodeRegionEntry entry = ionTable->regionEntry(i); + + // Ensure native code offset for region falls within jitcode. + MOZ_ASSERT(entry.nativeOffset() <= code->instructionsSize()); + + // Read out script/pc stack and verify. + JitcodeRegionEntry::ScriptPcIterator scriptPcIter = + entry.scriptPcIterator(); + while (scriptPcIter.hasMore()) { + uint32_t scriptIdx = 0, pcOffset = 0; + scriptPcIter.readNext(&scriptIdx, &pcOffset); + + // Ensure scriptIdx refers to a valid script in the list. + MOZ_ASSERT(scriptIdx < nativeToBytecodeScriptListLength_); + JSScript* script = nativeToBytecodeScriptList_[scriptIdx]; + + // Ensure pcOffset falls within the script. + MOZ_ASSERT(pcOffset < script->length()); + } + + // Obtain the original nativeOffset and pcOffset and script. + uint32_t curNativeOffset = entry.nativeOffset(); + JSScript* script = nullptr; + uint32_t curPcOffset = 0; + { + uint32_t scriptIdx = 0; + scriptPcIter.reset(); + scriptPcIter.readNext(&scriptIdx, &curPcOffset); + script = nativeToBytecodeScriptList_[scriptIdx]; + } + + // Read out nativeDeltas and pcDeltas and verify. + JitcodeRegionEntry::DeltaIterator deltaIter = entry.deltaIterator(); + while (deltaIter.hasMore()) { + uint32_t nativeDelta = 0; + int32_t pcDelta = 0; + deltaIter.readNext(&nativeDelta, &pcDelta); + + curNativeOffset += nativeDelta; + curPcOffset = uint32_t(int32_t(curPcOffset) + pcDelta); + + // Ensure that nativeOffset still falls within jitcode after delta. + MOZ_ASSERT(curNativeOffset <= code->instructionsSize()); + + // Ensure that pcOffset still falls within bytecode after delta. + MOZ_ASSERT(curPcOffset < script->length()); + } + } +#endif // DEBUG +} + +void CodeGeneratorShared::markSafepoint(LInstruction* ins) { + markSafepointAt(masm.currentOffset(), ins); +} + +void CodeGeneratorShared::markSafepointAt(uint32_t offset, LInstruction* ins) { + MOZ_ASSERT_IF( + !safepointIndices_.empty() && !masm.oom(), + offset - safepointIndices_.back().displacement() >= sizeof(uint32_t)); + masm.propagateOOM(safepointIndices_.append( + CodegenSafepointIndex(offset, ins->safepoint()))); +} + +void CodeGeneratorShared::ensureOsiSpace() { + // For a refresher, an invalidation point is of the form: + // 1: call <target> + // 2: ... + // 3: <osipoint> + // + // The four bytes *before* instruction 2 are overwritten with an offset. + // Callers must ensure that the instruction itself has enough bytes to + // support this. + // + // The bytes *at* instruction 3 are overwritten with an invalidation jump. + // jump. These bytes may be in a completely different IR sequence, but + // represent the join point of the call out of the function. + // + // At points where we want to ensure that invalidation won't corrupt an + // important instruction, we make sure to pad with nops. + if (masm.currentOffset() - lastOsiPointOffset_ < + Assembler::PatchWrite_NearCallSize()) { + int32_t paddingSize = Assembler::PatchWrite_NearCallSize(); + paddingSize -= masm.currentOffset() - lastOsiPointOffset_; + for (int32_t i = 0; i < paddingSize; ++i) { + masm.nop(); + } + } + MOZ_ASSERT_IF(!masm.oom(), masm.currentOffset() - lastOsiPointOffset_ >= + Assembler::PatchWrite_NearCallSize()); + lastOsiPointOffset_ = masm.currentOffset(); +} + +uint32_t CodeGeneratorShared::markOsiPoint(LOsiPoint* ins) { + encode(ins->snapshot()); + ensureOsiSpace(); + + uint32_t offset = masm.currentOffset(); + SnapshotOffset so = ins->snapshot()->snapshotOffset(); + masm.propagateOOM(osiIndices_.append(OsiIndex(offset, so))); + + return offset; +} + +class OutOfLineTruncateSlow : public OutOfLineCodeBase<CodeGeneratorShared> { + FloatRegister src_; + Register dest_; + bool widenFloatToDouble_; + wasm::BytecodeOffset bytecodeOffset_; + bool preserveTls_; + + public: + OutOfLineTruncateSlow( + FloatRegister src, Register dest, bool widenFloatToDouble = false, + wasm::BytecodeOffset bytecodeOffset = wasm::BytecodeOffset(), + bool preserveTls = false) + : src_(src), + dest_(dest), + widenFloatToDouble_(widenFloatToDouble), + bytecodeOffset_(bytecodeOffset), + preserveTls_(preserveTls) {} + + void accept(CodeGeneratorShared* codegen) override { + codegen->visitOutOfLineTruncateSlow(this); + } + FloatRegister src() const { return src_; } + Register dest() const { return dest_; } + bool widenFloatToDouble() const { return widenFloatToDouble_; } + bool preserveTls() const { return preserveTls_; } + wasm::BytecodeOffset bytecodeOffset() const { return bytecodeOffset_; } +}; + +OutOfLineCode* CodeGeneratorShared::oolTruncateDouble( + FloatRegister src, Register dest, MInstruction* mir, + wasm::BytecodeOffset bytecodeOffset, bool preserveTls) { + MOZ_ASSERT_IF(IsCompilingWasm(), bytecodeOffset.isValid()); + + OutOfLineTruncateSlow* ool = new (alloc()) OutOfLineTruncateSlow( + src, dest, /* float32 */ false, bytecodeOffset, preserveTls); + addOutOfLineCode(ool, mir); + return ool; +} + +void CodeGeneratorShared::emitTruncateDouble(FloatRegister src, Register dest, + MInstruction* mir) { + MOZ_ASSERT(mir->isTruncateToInt32() || mir->isWasmBuiltinTruncateToInt32()); + wasm::BytecodeOffset bytecodeOffset = + mir->isTruncateToInt32() + ? mir->toTruncateToInt32()->bytecodeOffset() + : mir->toWasmBuiltinTruncateToInt32()->bytecodeOffset(); + OutOfLineCode* ool = oolTruncateDouble(src, dest, mir, bytecodeOffset); + + masm.branchTruncateDoubleMaybeModUint32(src, dest, ool->entry()); + masm.bind(ool->rejoin()); +} + +void CodeGeneratorShared::emitTruncateFloat32(FloatRegister src, Register dest, + MInstruction* mir) { + MOZ_ASSERT(mir->isTruncateToInt32() || mir->isWasmBuiltinTruncateToInt32()); + wasm::BytecodeOffset bytecodeOffset = + mir->isTruncateToInt32() + ? mir->toTruncateToInt32()->bytecodeOffset() + : mir->toWasmBuiltinTruncateToInt32()->bytecodeOffset(); + OutOfLineTruncateSlow* ool = new (alloc()) + OutOfLineTruncateSlow(src, dest, /* float32 */ true, bytecodeOffset); + addOutOfLineCode(ool, mir); + + masm.branchTruncateFloat32MaybeModUint32(src, dest, ool->entry()); + masm.bind(ool->rejoin()); +} + +void CodeGeneratorShared::visitOutOfLineTruncateSlow( + OutOfLineTruncateSlow* ool) { + FloatRegister src = ool->src(); + Register dest = ool->dest(); + + saveVolatile(dest); + masm.outOfLineTruncateSlow(src, dest, ool->widenFloatToDouble(), + gen->compilingWasm(), ool->bytecodeOffset()); + restoreVolatile(dest); + + masm.jump(ool->rejoin()); +} + +bool CodeGeneratorShared::omitOverRecursedCheck() const { + // If the current function makes no calls (which means it isn't recursive) + // and it uses only a small amount of stack space, it doesn't need a + // stack overflow check. Note that the actual number here is somewhat + // arbitrary, and codegen actually uses small bounded amounts of + // additional stack space in some cases too. + return frameSize() < MAX_UNCHECKED_LEAF_FRAME_SIZE && + !gen->needsOverrecursedCheck(); +} + +void CodeGeneratorShared::emitPreBarrier(Register elements, + const LAllocation* index) { + if (index->isConstant()) { + Address address(elements, ToInt32(index) * sizeof(Value)); + masm.guardedCallPreBarrier(address, MIRType::Value); + } else { + BaseObjectElementIndex address(elements, ToRegister(index)); + masm.guardedCallPreBarrier(address, MIRType::Value); + } +} + +void CodeGeneratorShared::emitPreBarrier(Address address) { + masm.guardedCallPreBarrier(address, MIRType::Value); +} + +void CodeGeneratorShared::jumpToBlock(MBasicBlock* mir) { + // Skip past trivial blocks. + mir = skipTrivialBlocks(mir); + + // No jump necessary if we can fall through to the next block. + if (isNextBlock(mir->lir())) { + return; + } + + masm.jump(mir->lir()->label()); +} + +Label* CodeGeneratorShared::getJumpLabelForBranch(MBasicBlock* block) { + // Skip past trivial blocks. + return skipTrivialBlocks(block)->lir()->label(); +} + +// This function is not used for MIPS/MIPS64. MIPS has branchToBlock. +#if !defined(JS_CODEGEN_MIPS32) && !defined(JS_CODEGEN_MIPS64) +void CodeGeneratorShared::jumpToBlock(MBasicBlock* mir, + Assembler::Condition cond) { + // Skip past trivial blocks. + masm.j(cond, skipTrivialBlocks(mir)->lir()->label()); +} +#endif + +ReciprocalMulConstants CodeGeneratorShared::computeDivisionConstants( + uint32_t d, int maxLog) { + MOZ_ASSERT(maxLog >= 2 && maxLog <= 32); + // In what follows, 0 < d < 2^maxLog and d is not a power of 2. + MOZ_ASSERT(d < (uint64_t(1) << maxLog) && (d & (d - 1)) != 0); + + // Speeding up division by non power-of-2 constants is possible by + // calculating, during compilation, a value M such that high-order + // bits of M*n correspond to the result of the division of n by d. + // No value of M can serve this purpose for arbitrarily big values + // of n but, for optimizing integer division, we're just concerned + // with values of n whose absolute value is bounded (by fitting in + // an integer type, say). With this in mind, we'll find a constant + // M as above that works for -2^maxLog <= n < 2^maxLog; maxLog can + // then be 31 for signed division or 32 for unsigned division. + // + // The original presentation of this technique appears in Hacker's + // Delight, a book by Henry S. Warren, Jr.. A proof of correctness + // for our version follows; we'll denote maxLog by L in the proof, + // for conciseness. + // + // Formally, for |d| < 2^L, we'll compute two magic values M and s + // in the ranges 0 <= M < 2^(L+1) and 0 <= s <= L such that + // (M * n) >> (32 + s) = floor(n/d) if 0 <= n < 2^L + // (M * n) >> (32 + s) = ceil(n/d) - 1 if -2^L <= n < 0. + // + // Define p = 32 + s, M = ceil(2^p/d), and assume that s satisfies + // M - 2^p/d <= 2^(p-L)/d. (1) + // (Observe that p = CeilLog32(d) + L satisfies this, as the right + // side of (1) is at least one in this case). Then, + // + // a) If p <= CeilLog32(d) + L, then M < 2^(L+1) - 1. + // Proof: Indeed, M is monotone in p and, for p equal to the above + // value, the bounds 2^L > d >= 2^(p-L-1) + 1 readily imply that + // 2^p / d < 2^p/(d - 1) * (d - 1)/d + // <= 2^(L+1) * (1 - 1/d) < 2^(L+1) - 2. + // The claim follows by applying the ceiling function. + // + // b) For any 0 <= n < 2^L, floor(Mn/2^p) = floor(n/d). + // Proof: Put x = floor(Mn/2^p); it's the unique integer for which + // Mn/2^p - 1 < x <= Mn/2^p. (2) + // Using M >= 2^p/d on the LHS and (1) on the RHS, we get + // n/d - 1 < x <= n/d + n/(2^L d) < n/d + 1/d. + // Since x is an integer, it's not in the interval (n/d, (n+1)/d), + // and so n/d - 1 < x <= n/d, which implies x = floor(n/d). + // + // c) For any -2^L <= n < 0, floor(Mn/2^p) + 1 = ceil(n/d). + // Proof: The proof is similar. Equation (2) holds as above. Using + // M > 2^p/d (d isn't a power of 2) on the RHS and (1) on the LHS, + // n/d + n/(2^L d) - 1 < x < n/d. + // Using n >= -2^L and summing 1, + // n/d - 1/d < x + 1 < n/d + 1. + // Since x + 1 is an integer, this implies n/d <= x + 1 < n/d + 1. + // In other words, x + 1 = ceil(n/d). + // + // Condition (1) isn't necessary for the existence of M and s with + // the properties above. Hacker's Delight provides a slightly less + // restrictive condition when d >= 196611, at the cost of a 3-page + // proof of correctness, for the case L = 31. + // + // Note that, since d*M - 2^p = d - (2^p)%d, (1) can be written as + // 2^(p-L) >= d - (2^p)%d. + // In order to avoid overflow in the (2^p) % d calculation, we can + // compute it as (2^p-1) % d + 1, where 2^p-1 can then be computed + // without overflow as UINT64_MAX >> (64-p). + + // We now compute the least p >= 32 with the property above... + int32_t p = 32; + while ((uint64_t(1) << (p - maxLog)) + (UINT64_MAX >> (64 - p)) % d + 1 < d) { + p++; + } + + // ...and the corresponding M. For either the signed (L=31) or the + // unsigned (L=32) case, this value can be too large (cf. item a). + // Codegen can still multiply by M by multiplying by (M - 2^L) and + // adjusting the value afterwards, if this is the case. + ReciprocalMulConstants rmc; + rmc.multiplier = (UINT64_MAX >> (64 - p)) / d + 1; + rmc.shiftAmount = p - 32; + + return rmc; +} + +#ifdef JS_TRACE_LOGGING + +void CodeGeneratorShared::emitTracelogScript(bool isStart) { + if (!TraceLogTextIdEnabled(TraceLogger_Scripts)) { + return; + } + + Label done; + + AllocatableRegisterSet regs(RegisterSet::Volatile()); + Register logger = regs.takeAnyGeneral(); + Register script = regs.takeAnyGeneral(); + + masm.Push(logger); + + masm.loadTraceLogger(logger); + masm.branchTestPtr(Assembler::Zero, logger, logger, &done); + + Address enabledAddress(logger, TraceLoggerThread::offsetOfEnabled()); + masm.branch32(Assembler::Equal, enabledAddress, Imm32(0), &done); + + masm.Push(script); + + CodeOffset patchScript = masm.movWithPatch(ImmWord(0), script); + masm.propagateOOM(patchableTLScripts_.append(patchScript)); + + if (isStart) { + masm.tracelogStartId(logger, script); + } else { + masm.tracelogStopId(logger, script); + } + + masm.Pop(script); + + masm.bind(&done); + + masm.Pop(logger); +} + +void CodeGeneratorShared::emitTracelogTree(bool isStart, uint32_t textId) { + if (!TraceLogTextIdEnabled(textId)) { + return; + } + + Label done; + AllocatableRegisterSet regs(RegisterSet::Volatile()); + Register logger = regs.takeAnyGeneral(); + + masm.Push(logger); + + masm.loadTraceLogger(logger); + masm.branchTestPtr(Assembler::Zero, logger, logger, &done); + + Address enabledAddress(logger, TraceLoggerThread::offsetOfEnabled()); + masm.branch32(Assembler::Equal, enabledAddress, Imm32(0), &done); + + if (isStart) { + masm.tracelogStartId(logger, textId); + } else { + masm.tracelogStopId(logger, textId); + } + + masm.bind(&done); + + masm.Pop(logger); +} + +void CodeGeneratorShared::emitTracelogTree(bool isStart, const char* text, + TraceLoggerTextId enabledTextId) { + if (!TraceLogTextIdEnabled(enabledTextId)) { + return; + } + + Label done; + + AllocatableRegisterSet regs(RegisterSet::Volatile()); + Register loggerReg = regs.takeAnyGeneral(); + Register eventReg = regs.takeAnyGeneral(); + + masm.Push(loggerReg); + + masm.loadTraceLogger(loggerReg); + masm.branchTestPtr(Assembler::Zero, loggerReg, loggerReg, &done); + + Address enabledAddress(loggerReg, TraceLoggerThread::offsetOfEnabled()); + masm.branch32(Assembler::Equal, enabledAddress, Imm32(0), &done); + + masm.Push(eventReg); + + PatchableTLEvent patchEvent(masm.movWithPatch(ImmWord(0), eventReg), text); + masm.propagateOOM(patchableTLEvents_.append(std::move(patchEvent))); + + if (isStart) { + masm.tracelogStartId(loggerReg, eventReg); + } else { + masm.tracelogStopId(loggerReg, eventReg); + } + + masm.Pop(eventReg); + + masm.bind(&done); + + masm.Pop(loggerReg); +} +#endif + +} // namespace jit +} // namespace js |