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webkit / WebKit / fe3f8a9f58c921838bd3a920db5f85be838171cd / . / Source / JavaScriptCore / bytecompiler / BytecodeGenerator.cpp
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/*
* Copyright (C) 2008-2019 Apple Inc. All rights reserved.
* Copyright (C) 2008 Cameron Zwarich <cwzwarich@uwaterloo.ca>
* Copyright (C) 2012 Igalia, S.L.
*
* 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.
* 3. Neither the name of Apple Inc. ("Apple") nor the names of
* its contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "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 OR ITS 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.
*/
#include "config.h"
#include "BytecodeGenerator.h"
#include "ArithProfile.h"
#include "BuiltinExecutables.h"
#include "BuiltinNames.h"
#include "BytecodeGeneratorBaseInlines.h"
#include "BytecodeGeneratorification.h"
#include "BytecodeLivenessAnalysis.h"
#include "BytecodeUseDef.h"
#include "CatchScope.h"
#include "DefinePropertyAttributes.h"
#include "Interpreter.h"
#include "JSAsyncGenerator.h"
#include "JSBigInt.h"
#include "JSCInlines.h"
#include "JSFunction.h"
#include "JSGeneratorFunction.h"
#include "JSImmutableButterfly.h"
#include "JSLexicalEnvironment.h"
#include "JSTemplateObjectDescriptor.h"
#include "LinkTimeConstant.h"
#include "LowLevelInterpreter.h"
#include "Options.h"
#include "PreciseJumpTargetsInlines.h"
#include "StackAlignment.h"
#include "StrongInlines.h"
#include "SuperSamplerBytecodeScope.h"
#include "UnlinkedCodeBlock.h"
#include "UnlinkedEvalCodeBlock.h"
#include "UnlinkedFunctionCodeBlock.h"
#include "UnlinkedMetadataTableInlines.h"
#include "UnlinkedModuleProgramCodeBlock.h"
#include "UnlinkedProgramCodeBlock.h"
#include <wtf/BitVector.h>
#include <wtf/CommaPrinter.h>
#include <wtf/Optional.h>
#include <wtf/SmallPtrSet.h>
#include <wtf/StdLibExtras.h>
#include <wtf/text/WTFString.h>
namespace JSC {
template<typename CallOp, typename = std::true_type>
struct VarArgsOp;
template<typename CallOp>
struct VarArgsOp<CallOp, std::enable_if_t<std::is_same<CallOp, OpTailCall>::value, std::true_type>> {
using type = OpTailCallVarargs;
};
template<typename CallOp>
struct VarArgsOp<CallOp, std::enable_if_t<!std::is_same<CallOp, OpTailCall>::value, std::true_type>> {
using type = OpCallVarargs;
};
template<>
void GenericLabel<JSGeneratorTraits>::setLocation(BytecodeGenerator& generator, unsigned location)
{
m_location = location;
for (auto offset : m_unresolvedJumps) {
auto instruction = generator.m_writer.ref(offset);
int target = m_location - offset;
#define CASE(__op) \
case __op::opcodeID: \
instruction->cast<__op>()->setTargetLabel(BoundLabel(target), [&]() { \
generator.m_codeBlock->addOutOfLineJumpTarget(instruction.offset(), target); \
return BoundLabel(); \
}); \
break;
switch (instruction->opcodeID()) {
CASE(OpJmp)
CASE(OpJtrue)
CASE(OpJfalse)
CASE(OpJeqNull)
CASE(OpJneqNull)
CASE(OpJundefinedOrNull)
CASE(OpJnundefinedOrNull)
CASE(OpJeq)
CASE(OpJstricteq)
CASE(OpJneq)
CASE(OpJneqPtr)
CASE(OpJnstricteq)
CASE(OpJless)
CASE(OpJlesseq)
CASE(OpJgreater)
CASE(OpJgreatereq)
CASE(OpJnless)
CASE(OpJnlesseq)
CASE(OpJngreater)
CASE(OpJngreatereq)
CASE(OpJbelow)
CASE(OpJbeloweq)
default:
ASSERT_NOT_REACHED();
}
#undef CASE
}
}
void Variable::dump(PrintStream& out) const
{
out.print(
"{ident = ", m_ident,
", offset = ", m_offset,
", local = ", RawPointer(m_local),
", attributes = ", m_attributes,
", kind = ", m_kind,
", symbolTableConstantIndex = ", m_symbolTableConstantIndex,
", isLexicallyScoped = ", m_isLexicallyScoped, "}");
}
FinallyContext::FinallyContext(BytecodeGenerator& generator, Label& finallyLabel)
: m_outerContext(generator.m_currentFinallyContext)
, m_finallyLabel(&finallyLabel)
{
ASSERT(m_jumps.isEmpty());
m_completionRecord.typeRegister = generator.newTemporary();
m_completionRecord.valueRegister = generator.newTemporary();
generator.emitLoad(completionTypeRegister(), CompletionType::Normal);
generator.moveEmptyValue(completionValueRegister());
}
ParserError BytecodeGenerator::generate()
{
m_codeBlock->setThisRegister(m_thisRegister.virtualRegister());
emitLogShadowChickenPrologueIfNecessary();
// If we have declared a variable named "arguments" and we are using arguments then we should
// perform that assignment now.
if (m_needToInitializeArguments)
initializeVariable(variable(propertyNames().arguments), m_argumentsRegister);
if (m_restParameter)
m_restParameter->emit(*this);
{
RefPtr<RegisterID> temp = newTemporary();
RefPtr<RegisterID> tolLevelScope;
for (auto functionPair : m_functionsToInitialize) {
FunctionMetadataNode* metadata = functionPair.first;
FunctionVariableType functionType = functionPair.second;
emitNewFunction(temp.get(), metadata);
if (functionType == NormalFunctionVariable)
initializeVariable(variable(metadata->ident()), temp.get());
else if (functionType == TopLevelFunctionVariable) {
if (!tolLevelScope) {
// We know this will resolve to the top level scope or global object because our parser/global initialization code
// doesn't allow let/const/class variables to have the same names as functions.
// This is a top level function, and it's an error to ever create a top level function
// name that would resolve to a lexical variable. E.g:
// ```
// function f() {
// {
// let x;
// {
// //// error thrown here
// eval("function x(){}");
// }
// }
// }
// ```
// Therefore, we're guaranteed to have this resolve to a top level variable.
RefPtr<RegisterID> tolLevelObjectScope = emitResolveScope(nullptr, Variable(metadata->ident()));
tolLevelScope = newBlockScopeVariable();
move(tolLevelScope.get(), tolLevelObjectScope.get());
}
emitPutToScope(tolLevelScope.get(), Variable(metadata->ident()), temp.get(), ThrowIfNotFound, InitializationMode::NotInitialization);
} else
RELEASE_ASSERT_NOT_REACHED();
}
}
bool callingClassConstructor = false;
switch (constructorKind()) {
case ConstructorKind::None:
case ConstructorKind::Naked:
break;
case ConstructorKind::Base:
case ConstructorKind::Extends:
callingClassConstructor = !isConstructor();
break;
}
if (!callingClassConstructor)
m_scopeNode->emitBytecode(*this);
else {
// At this point we would have emitted an unconditional throw followed by some nonsense that's
// just an artifact of how this generator is structured. That code never runs, but it confuses
// bytecode analyses because it constitutes an unterminated basic block. So, we terminate the
// basic block the strongest way possible.
emitUnreachable();
}
for (auto& handler : m_exceptionHandlersToEmit) {
Ref<Label> realCatchTarget = newLabel();
TryData* tryData = handler.tryData;
OpCatch::emit(this, handler.exceptionRegister, handler.thrownValueRegister);
realCatchTarget->setLocation(*this, m_lastInstruction.offset());
if (handler.completionTypeRegister.isValid()) {
RegisterID completionTypeRegister { handler.completionTypeRegister };
CompletionType completionType =
tryData->handlerType == HandlerType::Finally || tryData->handlerType == HandlerType::SynthesizedFinally
? CompletionType::Throw
: CompletionType::Normal;
emitLoad(&completionTypeRegister, completionType);
}
m_codeBlock->addJumpTarget(m_lastInstruction.offset());
emitJump(tryData->target.get());
tryData->target = WTFMove(realCatchTarget);
}
m_staticPropertyAnalyzer.kill();
for (auto& range : m_tryRanges) {
int start = range.start->bind();
int end = range.end->bind();
// This will happen for empty try blocks and for some cases of finally blocks:
//
// try {
// try {
// } finally {
// return 42;
// // *HERE*
// }
// } finally {
// print("things");
// }
//
// The return will pop scopes to execute the outer finally block. But this includes
// popping the try context for the inner try. The try context is live in the fall-through
// part of the finally block not because we will emit a handler that overlaps the finally,
// but because we haven't yet had a chance to plant the catch target. Then when we finish
// emitting code for the outer finally block, we repush the try contex, this time with a
// new start index. But that means that the start index for the try range corresponding
// to the inner-finally-following-the-return (marked as "*HERE*" above) will be greater
// than the end index of the try block. This is harmless since end < start handlers will
// never get matched in our logic, but we do the runtime a favor and choose to not emit
// such handlers at all.
if (end <= start)
continue;
UnlinkedHandlerInfo info(static_cast<uint32_t>(start), static_cast<uint32_t>(end),
static_cast<uint32_t>(range.tryData->target->bind()), range.tryData->handlerType);
m_codeBlock->addExceptionHandler(info);
}
if (isGeneratorOrAsyncFunctionBodyParseMode(m_codeBlock->parseMode()))
performGeneratorification(*this, m_codeBlock.get(), m_writer, m_generatorFrameSymbolTable.get(), m_generatorFrameSymbolTableIndex);
RELEASE_ASSERT(static_cast<unsigned>(m_codeBlock->numCalleeLocals()) < static_cast<unsigned>(FirstConstantRegisterIndex));
m_codeBlock->setInstructions(m_writer.finalize());
m_codeBlock->shrinkToFit();
if (m_expressionTooDeep)
return ParserError(ParserError::OutOfMemory);
return ParserError(ParserError::ErrorNone);
}
BytecodeGenerator::BytecodeGenerator(VM& vm, ProgramNode* programNode, UnlinkedProgramCodeBlock* codeBlock, OptionSet<CodeGenerationMode> codeGenerationMode, const VariableEnvironment* parentScopeTDZVariables)
: BytecodeGeneratorBase(Strong<UnlinkedCodeBlock>(vm, codeBlock), CodeBlock::llintBaselineCalleeSaveSpaceAsVirtualRegisters())
, m_codeGenerationMode(codeGenerationMode)
, m_scopeNode(programNode)
, m_thisRegister(CallFrame::thisArgumentOffset())
, m_codeType(GlobalCode)
, m_vm(vm)
, m_needsToUpdateArrowFunctionContext(programNode->usesArrowFunction() || programNode->usesEval())
{
ASSERT_UNUSED(parentScopeTDZVariables, !parentScopeTDZVariables->size());
m_codeBlock->setNumParameters(1); // Allocate space for "this"
emitEnter();
allocateAndEmitScope();
emitCheckTraps();
const FunctionStack& functionStack = programNode->functionStack();
for (auto* function : functionStack)
m_functionsToInitialize.append(std::make_pair(function, TopLevelFunctionVariable));
if (Options::validateBytecode()) {
for (auto& entry : programNode->varDeclarations())
RELEASE_ASSERT(entry.value.isVar());
}
codeBlock->setVariableDeclarations(programNode->varDeclarations());
codeBlock->setLexicalDeclarations(programNode->lexicalVariables());
// Even though this program may have lexical variables that go under TDZ, when linking the get_from_scope/put_to_scope
// operations we emit we will have ResolveTypes that implictly do TDZ checks. Therefore, we don't need
// additional TDZ checks on top of those. This is why we can omit pushing programNode->lexicalVariables()
// to the TDZ stack.
if (needsToUpdateArrowFunctionContext()) {
initializeArrowFunctionContextScopeIfNeeded();
emitPutThisToArrowFunctionContextScope();
}
}
BytecodeGenerator::BytecodeGenerator(VM& vm, FunctionNode* functionNode, UnlinkedFunctionCodeBlock* codeBlock, OptionSet<CodeGenerationMode> codeGenerationMode, const VariableEnvironment* parentScopeTDZVariables)
: BytecodeGeneratorBase(Strong<UnlinkedCodeBlock>(vm, codeBlock), CodeBlock::llintBaselineCalleeSaveSpaceAsVirtualRegisters())
, m_codeGenerationMode(codeGenerationMode)
, m_scopeNode(functionNode)
, m_codeType(FunctionCode)
, m_vm(vm)
, m_isBuiltinFunction(codeBlock->isBuiltinFunction())
, m_usesNonStrictEval(codeBlock->usesEval() && !codeBlock->isStrictMode())
// FIXME: We should be able to have tail call elimination with the profiler
// enabled. This is currently not possible because the profiler expects
// op_will_call / op_did_call pairs before and after a call, which are not
// compatible with tail calls (we have no way of emitting op_did_call).
// https://bugs.webkit.org/show_bug.cgi?id=148819
//
// Note that we intentionally enable tail call for naked constructors since it does not have special code for "return".
, m_inTailPosition(Options::useTailCalls() && !isConstructor() && constructorKind() == ConstructorKind::None && isStrictMode())
, m_needsToUpdateArrowFunctionContext(functionNode->usesArrowFunction() || functionNode->usesEval())
, m_derivedContextType(codeBlock->derivedContextType())
{
SymbolTable* functionSymbolTable = SymbolTable::create(m_vm);
functionSymbolTable->setUsesNonStrictEval(m_usesNonStrictEval);
int symbolTableConstantIndex = 0;
FunctionParameters& parameters = *functionNode->parameters();
// http://www.ecma-international.org/ecma-262/6.0/index.html#sec-functiondeclarationinstantiation
// This implements IsSimpleParameterList in the Ecma 2015 spec.
// If IsSimpleParameterList is false, we will create a strict-mode like arguments object.
// IsSimpleParameterList is false if the argument list contains any default parameter values,
// a rest parameter, or any destructuring patterns.
// If we do have default parameters, destructuring parameters, or a rest parameter, our parameters will be allocated in a different scope.
bool isSimpleParameterList = parameters.isSimpleParameterList();
SourceParseMode parseMode = codeBlock->parseMode();
bool containsArrowOrEvalButNotInArrowBlock = ((functionNode->usesArrowFunction() && functionNode->doAnyInnerArrowFunctionsUseAnyFeature()) || functionNode->usesEval()) && !m_codeBlock->isArrowFunction();
bool shouldCaptureSomeOfTheThings = shouldEmitDebugHooks() || functionNode->needsActivation() || containsArrowOrEvalButNotInArrowBlock;
bool shouldCaptureAllOfTheThings = shouldEmitDebugHooks() || codeBlock->usesEval();
bool needsArguments = ((functionNode->usesArguments() && !codeBlock->isArrowFunction()) || codeBlock->usesEval() || (functionNode->usesArrowFunction() && !codeBlock->isArrowFunction() && isArgumentsUsedInInnerArrowFunction()));
if (isGeneratorOrAsyncFunctionBodyParseMode(parseMode)) {
// Generator and AsyncFunction never provides "arguments". "arguments" reference will be resolved in an upper generator function scope.
needsArguments = false;
}
if (isGeneratorOrAsyncFunctionWrapperParseMode(parseMode) && needsArguments) {
// Generator does not provide "arguments". Instead, wrapping GeneratorFunction provides "arguments".
// This is because arguments of a generator should be evaluated before starting it.
// To workaround it, we evaluate these arguments as arguments of a wrapping generator function, and reference it from a generator.
//
// function *gen(a, b = hello())
// {
// return {
// @generatorNext: function (@generator, @generatorState, @generatorValue, @generatorResumeMode, @generatorFrame)
// {
// arguments; // This `arguments` should reference to the gen's arguments.
// ...
// }
// }
// }
shouldCaptureSomeOfTheThings = true;
}
if (shouldCaptureAllOfTheThings)
functionNode->varDeclarations().markAllVariablesAsCaptured();
auto captures = scopedLambda<bool (UniquedStringImpl*)>([&] (UniquedStringImpl* uid) -> bool {
if (!shouldCaptureSomeOfTheThings)
return false;
if (needsArguments && uid == propertyNames().arguments.impl()) {
// Actually, we only need to capture the arguments object when we "need full activation"
// because of name scopes. But historically we did it this way, so for now we just preserve
// the old behavior.
// FIXME: https://bugs.webkit.org/show_bug.cgi?id=143072
return true;
}
return functionNode->captures(uid);
});
auto varKind = [&] (UniquedStringImpl* uid) -> VarKind {
return captures(uid) ? VarKind::Scope : VarKind::Stack;
};
m_calleeRegister.setIndex(CallFrameSlot::callee);
initializeParameters(parameters);
ASSERT(!(isSimpleParameterList && m_restParameter));
emitEnter();
if (isGeneratorOrAsyncFunctionBodyParseMode(parseMode))
m_generatorRegister = &m_parameters[1];
allocateAndEmitScope();
emitCheckTraps();
if (functionNameIsInScope(functionNode->ident(), functionNode->functionMode())) {
ASSERT(parseMode != SourceParseMode::GeneratorBodyMode);
ASSERT(!isAsyncFunctionBodyParseMode(parseMode));
bool isDynamicScope = functionNameScopeIsDynamic(codeBlock->usesEval(), codeBlock->isStrictMode());
bool isFunctionNameCaptured = captures(functionNode->ident().impl());
bool markAsCaptured = isDynamicScope || isFunctionNameCaptured;
emitPushFunctionNameScope(functionNode->ident(), &m_calleeRegister, markAsCaptured);
}
if (shouldCaptureSomeOfTheThings)
m_lexicalEnvironmentRegister = addVar();
if (isGeneratorOrAsyncFunctionBodyParseMode(parseMode) || shouldCaptureSomeOfTheThings || shouldEmitTypeProfilerHooks())
symbolTableConstantIndex = addConstantValue(functionSymbolTable)->index();
// We can allocate the "var" environment if we don't have default parameter expressions. If we have
// default parameter expressions, we have to hold off on allocating the "var" environment because
// the parent scope of the "var" environment is the parameter environment.
if (isSimpleParameterList)
initializeVarLexicalEnvironment(symbolTableConstantIndex, functionSymbolTable, shouldCaptureSomeOfTheThings);
// Figure out some interesting facts about our arguments.
bool capturesAnyArgumentByName = false;
if (functionNode->hasCapturedVariables()) {
FunctionParameters& parameters = *functionNode->parameters();
for (size_t i = 0; i < parameters.size(); ++i) {
auto pattern = parameters.at(i).first;
if (!pattern->isBindingNode())
continue;
const Identifier& ident = static_cast<const BindingNode*>(pattern)->boundProperty();
capturesAnyArgumentByName |= captures(ident.impl());
}
}
if (capturesAnyArgumentByName)
ASSERT(m_lexicalEnvironmentRegister);
// Need to know what our functions are called. Parameters have some goofy behaviors when it
// comes to functions of the same name.
for (FunctionMetadataNode* function : functionNode->functionStack())
m_functions.add(function->ident().impl());
if (needsArguments) {
// Create the arguments object now. We may put the arguments object into the activation if
// it is captured. Either way, we create two arguments object variables: one is our
// private variable that is immutable, and another that is the user-visible variable. The
// immutable one is only used here, or during formal parameter resolutions if we opt for
// DirectArguments.
m_argumentsRegister = addVar();
m_argumentsRegister->ref();
}
if (needsArguments && !codeBlock->isStrictMode() && isSimpleParameterList) {
// If we captured any formal parameter by name, then we use ScopedArguments. Otherwise we
// use DirectArguments. With ScopedArguments, we lift all of our arguments into the
// activation.
if (capturesAnyArgumentByName) {
functionSymbolTable->setArgumentsLength(vm, parameters.size());
// For each parameter, we have two possibilities:
// Either it's a binding node with no function overlap, in which case it gets a name
// in the symbol table - or it just gets space reserved in the symbol table. Either
// way we lift the value into the scope.
for (unsigned i = 0; i < parameters.size(); ++i) {
ScopeOffset offset = functionSymbolTable->takeNextScopeOffset(NoLockingNecessary);
functionSymbolTable->setArgumentOffset(vm, i, offset);
if (UniquedStringImpl* name = visibleNameForParameter(parameters.at(i).first)) {
VarOffset varOffset(offset);
SymbolTableEntry entry(varOffset);
// Stores to these variables via the ScopedArguments object will not do
// notifyWrite(), since that would be cumbersome. Also, watching formal
// parameters when "arguments" is in play is unlikely to be super profitable.
// So, we just disable it.
entry.disableWatching(m_vm);
functionSymbolTable->set(NoLockingNecessary, name, entry);
}
OpPutToScope::emit(this, m_lexicalEnvironmentRegister, UINT_MAX, virtualRegisterForArgument(1 + i), GetPutInfo(ThrowIfNotFound, LocalClosureVar, InitializationMode::NotInitialization), SymbolTableOrScopeDepth::symbolTable(VirtualRegister { symbolTableConstantIndex }), offset.offset());
}
// This creates a scoped arguments object and copies the overflow arguments into the
// scope. It's the equivalent of calling ScopedArguments::createByCopying().
OpCreateScopedArguments::emit(this, m_argumentsRegister, m_lexicalEnvironmentRegister);
} else {
// We're going to put all parameters into the DirectArguments object. First ensure
// that the symbol table knows that this is happening.
for (unsigned i = 0; i < parameters.size(); ++i) {
if (UniquedStringImpl* name = visibleNameForParameter(parameters.at(i).first))
functionSymbolTable->set(NoLockingNecessary, name, SymbolTableEntry(VarOffset(DirectArgumentsOffset(i))));
}
OpCreateDirectArguments::emit(this, m_argumentsRegister);
}
} else if (isSimpleParameterList) {
// Create the formal parameters the normal way. Any of them could be captured, or not. If
// captured, lift them into the scope. We cannot do this if we have default parameter expressions
// because when default parameter expressions exist, they belong in their own lexical environment
// separate from the "var" lexical environment.
for (unsigned i = 0; i < parameters.size(); ++i) {
UniquedStringImpl* name = visibleNameForParameter(parameters.at(i).first);
if (!name)
continue;
if (!captures(name)) {
// This is the easy case - just tell the symbol table about the argument. It will
// be accessed directly.
functionSymbolTable->set(NoLockingNecessary, name, SymbolTableEntry(VarOffset(virtualRegisterForArgument(1 + i))));
continue;
}
ScopeOffset offset = functionSymbolTable->takeNextScopeOffset(NoLockingNecessary);
const Identifier& ident =
static_cast<const BindingNode*>(parameters.at(i).first)->boundProperty();
functionSymbolTable->set(NoLockingNecessary, name, SymbolTableEntry(VarOffset(offset)));
OpPutToScope::emit(this, m_lexicalEnvironmentRegister, addConstant(ident), virtualRegisterForArgument(1 + i), GetPutInfo(ThrowIfNotFound, LocalClosureVar, InitializationMode::NotInitialization), SymbolTableOrScopeDepth::symbolTable(VirtualRegister { symbolTableConstantIndex }), offset.offset());
}
}
if (needsArguments && (codeBlock->isStrictMode() || !isSimpleParameterList)) {
// Allocate a cloned arguments object.
OpCreateClonedArguments::emit(this, m_argumentsRegister);
}
// There are some variables that need to be preinitialized to something other than Undefined:
//
// - "arguments": unless it's used as a function or parameter, this should refer to the
// arguments object.
//
// - functions: these always override everything else.
//
// The most logical way to do all of this is to initialize none of the variables until now,
// and then initialize them in BytecodeGenerator::generate() in such an order that the rules
// for how these things override each other end up holding. We would initialize "arguments" first,
// then all arguments, then the functions.
//
// But some arguments are already initialized by default, since if they aren't captured and we
// don't have "arguments" then we just point the symbol table at the stack slot of those
// arguments. We end up initializing the rest of the arguments that have an uncomplicated
// binding (i.e. don't involve destructuring) above when figuring out how to lay them out,
// because that's just the simplest thing. This means that when we initialize them, we have to
// watch out for the things that override arguments (namely, functions).
// This is our final act of weirdness. "arguments" is overridden by everything except the
// callee. We add it to the symbol table if it's not already there and it's not an argument.
bool shouldCreateArgumentsVariableInParameterScope = false;
if (needsArguments) {
// If "arguments" is overridden by a function or destructuring parameter name, then it's
// OK for us to call createVariable() because it won't change anything. It's also OK for
// us to them tell BytecodeGenerator::generate() to write to it because it will do so
// before it initializes functions and destructuring parameters. But if "arguments" is
// overridden by a "simple" function parameter, then we have to bail: createVariable()
// would assert and BytecodeGenerator::generate() would write the "arguments" after the
// argument value had already been properly initialized.
bool haveParameterNamedArguments = false;
for (unsigned i = 0; i < parameters.size(); ++i) {
UniquedStringImpl* name = visibleNameForParameter(parameters.at(i).first);
if (name == propertyNames().arguments.impl()) {
haveParameterNamedArguments = true;
break;
}
}
bool shouldCreateArgumensVariable = !haveParameterNamedArguments
&& !SourceParseModeSet(SourceParseMode::ArrowFunctionMode, SourceParseMode::AsyncArrowFunctionMode).contains(m_codeBlock->parseMode());
shouldCreateArgumentsVariableInParameterScope = shouldCreateArgumensVariable && !isSimpleParameterList;
// Do not create arguments variable in case of Arrow function. Value will be loaded from parent scope
if (shouldCreateArgumensVariable && !shouldCreateArgumentsVariableInParameterScope) {
createVariable(
propertyNames().arguments, varKind(propertyNames().arguments.impl()), functionSymbolTable);
m_needToInitializeArguments = true;
}
}
for (FunctionMetadataNode* function : functionNode->functionStack()) {
const Identifier& ident = function->ident();
createVariable(ident, varKind(ident.impl()), functionSymbolTable);
m_functionsToInitialize.append(std::make_pair(function, NormalFunctionVariable));
}
for (auto& entry : functionNode->varDeclarations()) {
ASSERT(!entry.value.isLet() && !entry.value.isConst());
if (!entry.value.isVar()) // This is either a parameter or callee.
continue;
if (shouldCreateArgumentsVariableInParameterScope && entry.key.get() == propertyNames().arguments.impl())
continue;
createVariable(Identifier::fromUid(m_vm, entry.key.get()), varKind(entry.key.get()), functionSymbolTable, IgnoreExisting);
}
if (functionNode->needsNewTargetRegisterForThisScope() || isNewTargetUsedInInnerArrowFunction() || codeBlock->usesEval())
m_newTargetRegister = addVar();
switch (parseMode) {
case SourceParseMode::GeneratorWrapperFunctionMode:
case SourceParseMode::GeneratorWrapperMethodMode: {
m_generatorRegister = addVar();
// FIXME: Emit to_this only when Generator uses it.
// https://bugs.webkit.org/show_bug.cgi?id=151586
emitToThis();
emitCreateGenerator(m_generatorRegister, &m_calleeRegister);
break;
}
case SourceParseMode::AsyncGeneratorWrapperMethodMode:
case SourceParseMode::AsyncGeneratorWrapperFunctionMode: {
m_generatorRegister = addVar();
// FIXME: Emit to_this only when Generator uses it.
// https://bugs.webkit.org/show_bug.cgi?id=151586
emitToThis();
emitCreateAsyncGenerator(m_generatorRegister, &m_calleeRegister);
break;
}
case SourceParseMode::AsyncArrowFunctionMode:
case SourceParseMode::AsyncMethodMode:
case SourceParseMode::AsyncFunctionMode: {
ASSERT(!isConstructor());
ASSERT(constructorKind() == ConstructorKind::None);
m_generatorRegister = addVar();
m_promiseRegister = addVar();
if (parseMode != SourceParseMode::AsyncArrowFunctionMode) {
// FIXME: Emit to_this only when AsyncFunctionBody uses it.
// https://bugs.webkit.org/show_bug.cgi?id=151586
emitToThis();
}
emitNewGenerator(m_generatorRegister);
emitNewPromise(promiseRegister(), m_isBuiltinFunction);
break;
}
case SourceParseMode::AsyncGeneratorBodyMode:
case SourceParseMode::AsyncFunctionBodyMode:
case SourceParseMode::AsyncArrowFunctionBodyMode:
case SourceParseMode::GeneratorBodyMode: {
// |this| is already filled correctly before here.
if (m_newTargetRegister)
emitLoad(m_newTargetRegister, jsUndefined());
break;
}
default: {
if (SourceParseMode::ArrowFunctionMode != parseMode) {
if (isConstructor()) {
if (m_newTargetRegister)
move(m_newTargetRegister, &m_thisRegister);
switch (constructorKind()) {
case ConstructorKind::Naked:
// Naked constructor not create |this| automatically.
break;
case ConstructorKind::None:
case ConstructorKind::Base:
emitCreateThis(&m_thisRegister);
break;
case ConstructorKind::Extends:
moveEmptyValue(&m_thisRegister);
break;
}
} else {
switch (constructorKind()) {
case ConstructorKind::None: {
bool shouldEmitToThis = false;
if (functionNode->usesThis() || codeBlock->usesEval() || m_scopeNode->doAnyInnerArrowFunctionsUseThis() || m_scopeNode->doAnyInnerArrowFunctionsUseEval())
shouldEmitToThis = true;
else if ((functionNode->usesSuperProperty() || m_scopeNode->doAnyInnerArrowFunctionsUseSuperProperty()) && !codeBlock->isStrictMode()) {
// We must emit to_this when we're not in strict mode because we
// will convert |this| to an object, and that object may be passed
// to a strict function as |this|. This is observable because that
// strict function's to_this will just return the object.
//
// We don't need to emit this for strict-mode code because
// strict-mode code may call another strict function, which will
// to_this if it directly uses this; this is OK, because we defer
// to_this until |this| is used directly. Strict-mode code might
// also call a sloppy mode function, and that will to_this, which
// will defer the conversion, again, until necessary.
shouldEmitToThis = true;
}
if (shouldEmitToThis)
emitToThis();
break;
}
case ConstructorKind::Naked:
emitThrowTypeError("Cannot call a constructor without |new|");
break;
case ConstructorKind::Base:
case ConstructorKind::Extends:
emitThrowTypeError("Cannot call a class constructor without |new|");
break;
}
}
}
break;
}
}
// We need load |super| & |this| for arrow function before initializeDefaultParameterValuesAndSetupFunctionScopeStack
// if we have default parameter expression. Because |super| & |this| values can be used there
if ((SourceParseModeSet(SourceParseMode::ArrowFunctionMode, SourceParseMode::AsyncArrowFunctionMode).contains(parseMode) && !isSimpleParameterList) || parseMode == SourceParseMode::AsyncArrowFunctionBodyMode) {
if (functionNode->usesThis() || functionNode->usesSuperProperty())
emitLoadThisFromArrowFunctionLexicalEnvironment();
if (m_scopeNode->needsNewTargetRegisterForThisScope())
emitLoadNewTargetFromArrowFunctionLexicalEnvironment();
}
if (needsToUpdateArrowFunctionContext() && !codeBlock->isArrowFunction()) {
bool canReuseLexicalEnvironment = isSimpleParameterList;
initializeArrowFunctionContextScopeIfNeeded(functionSymbolTable, canReuseLexicalEnvironment);
emitPutThisToArrowFunctionContextScope();
emitPutNewTargetToArrowFunctionContextScope();
emitPutDerivedConstructorToArrowFunctionContextScope();
}
// All "addVar()"s needs to happen before "initializeDefaultParameterValuesAndSetupFunctionScopeStack()" is called
// because a function's default parameter ExpressionNodes will use temporary registers.
pushTDZVariables(*parentScopeTDZVariables, TDZCheckOptimization::DoNotOptimize, TDZRequirement::UnderTDZ);
Ref<Label> catchLabel = newLabel();
TryData* tryFormalParametersData = nullptr;
bool needTryCatch = isAsyncFunctionWrapperParseMode(parseMode) && !isSimpleParameterList;
if (needTryCatch) {
Ref<Label> tryFormalParametersStart = newEmittedLabel();
tryFormalParametersData = pushTry(tryFormalParametersStart.get(), catchLabel.get(), HandlerType::SynthesizedCatch);
}
initializeDefaultParameterValuesAndSetupFunctionScopeStack(parameters, isSimpleParameterList, functionNode, functionSymbolTable, symbolTableConstantIndex, captures, shouldCreateArgumentsVariableInParameterScope);
if (needTryCatch) {
Ref<Label> didNotThrow = newLabel();
emitJump(didNotThrow.get());
emitLabel(catchLabel.get());
popTry(tryFormalParametersData, catchLabel.get());
RefPtr<RegisterID> thrownValue = newTemporary();
emitOutOfLineCatchHandler(thrownValue.get(), nullptr, tryFormalParametersData);
// @rejectPromiseWithFirstResolvingFunctionCallCheck(@promise, thrownValue);
// return @promise;
RefPtr<RegisterID> rejectPromise = moveLinkTimeConstant(nullptr, LinkTimeConstant::rejectPromiseWithFirstResolvingFunctionCallCheck);
CallArguments args(*this, nullptr, 2);
emitLoad(args.thisRegister(), jsUndefined());
move(args.argumentRegister(0), promiseRegister());
move(args.argumentRegister(1), thrownValue.get());
JSTextPosition divot(functionNode->firstLine(), functionNode->startOffset(), functionNode->lineStartOffset());
emitCall(newTemporary(), rejectPromise.get(), NoExpectedFunction, args, divot, divot, divot, DebuggableCall::No);
emitReturn(promiseRegister());
emitLabel(didNotThrow.get());
}
// If we don't have default parameter expression, then loading |this| inside an arrow function must be done
// after initializeDefaultParameterValuesAndSetupFunctionScopeStack() because that function sets up the
// SymbolTable stack and emitLoadThisFromArrowFunctionLexicalEnvironment() consults the SymbolTable stack
if (SourceParseModeSet(SourceParseMode::ArrowFunctionMode, SourceParseMode::AsyncArrowFunctionMode).contains(parseMode) && isSimpleParameterList) {
if (functionNode->usesThis() || functionNode->usesSuperProperty())
emitLoadThisFromArrowFunctionLexicalEnvironment();
if (m_scopeNode->needsNewTargetRegisterForThisScope())
emitLoadNewTargetFromArrowFunctionLexicalEnvironment();
}
// Set up the lexical environment scope as the generator frame. We store the saved and resumed generator registers into this scope with the symbol keys.
// Since they are symbol keyed, these variables cannot be reached from the usual code.
if (isGeneratorOrAsyncFunctionBodyParseMode(parseMode)) {
m_generatorFrameSymbolTable.set(m_vm, functionSymbolTable);
m_generatorFrameSymbolTableIndex = symbolTableConstantIndex;
if (m_lexicalEnvironmentRegister)
move(generatorFrameRegister(), m_lexicalEnvironmentRegister);
else {
// It would be possible that generator does not need to suspend and resume any registers.
// In this case, we would like to avoid creating a lexical environment as much as possible.
// op_create_generator_frame_environment is a marker, which is similar to op_yield.
// Generatorification inserts lexical environment creation if necessary. Otherwise, we convert it to op_mov frame, `undefined`.
OpCreateGeneratorFrameEnvironment::emit(this, generatorFrameRegister(), scopeRegister(), VirtualRegister { symbolTableConstantIndex }, addConstantValue(jsUndefined()));
}
static_assert(static_cast<unsigned>(JSGenerator::Field::Frame) == static_cast<unsigned>(JSAsyncGenerator::Field::Frame));
emitPutInternalField(generatorRegister(), static_cast<unsigned>(JSGenerator::Field::Frame), generatorFrameRegister());
}
bool shouldInitializeBlockScopedFunctions = false; // We generate top-level function declarations in ::generate().
pushLexicalScope(m_scopeNode, TDZCheckOptimization::Optimize, NestedScopeType::IsNotNested, nullptr, shouldInitializeBlockScopedFunctions);
}
BytecodeGenerator::BytecodeGenerator(VM& vm, EvalNode* evalNode, UnlinkedEvalCodeBlock* codeBlock, OptionSet<CodeGenerationMode> codeGenerationMode, const VariableEnvironment* parentScopeTDZVariables)
: BytecodeGeneratorBase(Strong<UnlinkedCodeBlock>(vm, codeBlock), CodeBlock::llintBaselineCalleeSaveSpaceAsVirtualRegisters())
, m_codeGenerationMode(codeGenerationMode)
, m_scopeNode(evalNode)
, m_thisRegister(CallFrame::thisArgumentOffset())
, m_codeType(EvalCode)
, m_vm(vm)
, m_usesNonStrictEval(codeBlock->usesEval() && !codeBlock->isStrictMode())
, m_needsToUpdateArrowFunctionContext(evalNode->usesArrowFunction() || evalNode->usesEval())
, m_derivedContextType(codeBlock->derivedContextType())
{
m_codeBlock->setNumParameters(1);
pushTDZVariables(*parentScopeTDZVariables, TDZCheckOptimization::DoNotOptimize, TDZRequirement::UnderTDZ);
emitEnter();
allocateAndEmitScope();
emitCheckTraps();
for (FunctionMetadataNode* function : evalNode->functionStack()) {
m_codeBlock->addFunctionDecl(makeFunction(function));
m_functionsToInitialize.append(std::make_pair(function, TopLevelFunctionVariable));
}
const VariableEnvironment& varDeclarations = evalNode->varDeclarations();
Vector<Identifier, 0, UnsafeVectorOverflow> variables;
Vector<Identifier, 0, UnsafeVectorOverflow> hoistedFunctions;
for (auto& entry : varDeclarations) {
ASSERT(entry.value.isVar());
ASSERT(entry.key->isAtom() || entry.key->isSymbol());
if (entry.value.isSloppyModeHoistingCandidate())
hoistedFunctions.append(Identifier::fromUid(m_vm, entry.key.get()));
else
variables.append(Identifier::fromUid(m_vm, entry.key.get()));
}
codeBlock->adoptVariables(variables);
codeBlock->adoptFunctionHoistingCandidates(WTFMove(hoistedFunctions));
if (evalNode->needsNewTargetRegisterForThisScope())
m_newTargetRegister = addVar();
if (codeBlock->isArrowFunctionContext() && (evalNode->usesThis() || evalNode->usesSuperProperty()))
emitLoadThisFromArrowFunctionLexicalEnvironment();
if (evalNode->needsNewTargetRegisterForThisScope())
emitLoadNewTargetFromArrowFunctionLexicalEnvironment();
if (needsToUpdateArrowFunctionContext() && !codeBlock->isArrowFunctionContext() && !isDerivedConstructorContext()) {
initializeArrowFunctionContextScopeIfNeeded();
emitPutThisToArrowFunctionContextScope();
}
bool shouldInitializeBlockScopedFunctions = false; // We generate top-level function declarations in ::generate().
pushLexicalScope(m_scopeNode, TDZCheckOptimization::Optimize, NestedScopeType::IsNotNested, nullptr, shouldInitializeBlockScopedFunctions);
}
BytecodeGenerator::BytecodeGenerator(VM& vm, ModuleProgramNode* moduleProgramNode, UnlinkedModuleProgramCodeBlock* codeBlock, OptionSet<CodeGenerationMode> codeGenerationMode, const VariableEnvironment* parentScopeTDZVariables)
: BytecodeGeneratorBase(Strong<UnlinkedCodeBlock>(vm, codeBlock), CodeBlock::llintBaselineCalleeSaveSpaceAsVirtualRegisters())
, m_codeGenerationMode(codeGenerationMode)
, m_scopeNode(moduleProgramNode)
, m_thisRegister(CallFrame::thisArgumentOffset())
, m_codeType(ModuleCode)
, m_vm(vm)
, m_usesNonStrictEval(false)
, m_needsToUpdateArrowFunctionContext(moduleProgramNode->usesArrowFunction() || moduleProgramNode->usesEval())
{
ASSERT_UNUSED(parentScopeTDZVariables, !parentScopeTDZVariables->size());
SymbolTable* moduleEnvironmentSymbolTable = SymbolTable::create(m_vm);
moduleEnvironmentSymbolTable->setUsesNonStrictEval(m_usesNonStrictEval);
moduleEnvironmentSymbolTable->setScopeType(SymbolTable::ScopeType::LexicalScope);
bool shouldCaptureAllOfTheThings = shouldEmitDebugHooks() || codeBlock->usesEval();
if (shouldCaptureAllOfTheThings)
moduleProgramNode->varDeclarations().markAllVariablesAsCaptured();
auto captures = [&] (UniquedStringImpl* uid) -> bool {
return moduleProgramNode->captures(uid);
};
auto lookUpVarKind = [&] (UniquedStringImpl* uid, const VariableEnvironmentEntry& entry) -> VarKind {
// Allocate the exported variables in the module environment.
if (entry.isExported())
return VarKind::Scope;
// Allocate the namespace variables in the module environment to instantiate
// it from the outside of the module code.
if (entry.isImportedNamespace())
return VarKind::Scope;
if (entry.isCaptured())
return VarKind::Scope;
return captures(uid) ? VarKind::Scope : VarKind::Stack;
};
emitEnter();
allocateAndEmitScope();
emitCheckTraps();
m_calleeRegister.setIndex(CallFrameSlot::callee);
m_codeBlock->setNumParameters(1); // Allocate space for "this"
// Now declare all variables.
createVariable(m_vm.propertyNames->builtinNames().metaPrivateName(), VarKind::Scope, moduleEnvironmentSymbolTable, VerifyExisting);
for (auto& entry : moduleProgramNode->varDeclarations()) {
ASSERT(!entry.value.isLet() && !entry.value.isConst());
if (!entry.value.isVar()) // This is either a parameter or callee.
continue;
// Imported bindings are not allocated in the module environment as usual variables' way.
// These references remain the "Dynamic" in the unlinked code block. Later, when linking
// the code block, we resolve the reference to the "ModuleVar".
if (entry.value.isImported() && !entry.value.isImportedNamespace())
continue;
createVariable(Identifier::fromUid(m_vm, entry.key.get()), lookUpVarKind(entry.key.get(), entry.value), moduleEnvironmentSymbolTable, IgnoreExisting);
}
VariableEnvironment& lexicalVariables = moduleProgramNode->lexicalVariables();
instantiateLexicalVariables(lexicalVariables, moduleEnvironmentSymbolTable, ScopeRegisterType::Block, lookUpVarKind);
// We keep the symbol table in the constant pool.
RegisterID* constantSymbolTable = nullptr;
if (shouldEmitTypeProfilerHooks())
constantSymbolTable = addConstantValue(moduleEnvironmentSymbolTable);
else
constantSymbolTable = addConstantValue(moduleEnvironmentSymbolTable->cloneScopePart(m_vm));
pushTDZVariables(lexicalVariables, TDZCheckOptimization::Optimize, TDZRequirement::UnderTDZ);
bool isWithScope = false;
m_lexicalScopeStack.append({ moduleEnvironmentSymbolTable, m_topMostScope, isWithScope, constantSymbolTable->index() });
emitPrefillStackTDZVariables(lexicalVariables, moduleEnvironmentSymbolTable);
// makeFunction assumes that there's correct TDZ stack entries.
// So it should be called after putting our lexical environment to the TDZ stack correctly.
for (FunctionMetadataNode* function : moduleProgramNode->functionStack()) {
const auto& iterator = moduleProgramNode->varDeclarations().find(function->ident().impl());
RELEASE_ASSERT(iterator != moduleProgramNode->varDeclarations().end());
RELEASE_ASSERT(!iterator->value.isImported());
VarKind varKind = lookUpVarKind(iterator->key.get(), iterator->value);
if (varKind == VarKind::Scope) {
// http://www.ecma-international.org/ecma-262/6.0/#sec-moduledeclarationinstantiation
// Section 15.2.1.16.4, step 16-a-iv-1.
// All heap allocated function declarations should be instantiated when the module environment
// is created. They include the exported function declarations and not-exported-but-heap-allocated
// function declarations. This is required because exported function should be instantiated before
// executing the any module in the dependency graph. This enables the modules to link the imported
// bindings before executing the any module code.
//
// And since function declarations are instantiated before executing the module body code, the spec
// allows the functions inside the module to be executed before its module body is executed under
// the circular dependencies. The following is the example.
//
// Module A (executed first):
// import { b } from "B";
// // Here, the module "B" is not executed yet, but the function declaration is already instantiated.
// // So we can call the function exported from "B".
// b();
//
// export function a() {
// }
//
// Module B (executed second):
// import { a } from "A";
//
// export function b() {
// c();
// }
//
// // c is not exported, but since it is referenced from the b, we should instantiate it before
// // executing the "B" module code.
// function c() {
// a();
// }
//
// Module EntryPoint (executed last):
// import "B";
// import "A";
//
m_codeBlock->addFunctionDecl(makeFunction(function));
} else {
// Stack allocated functions can be allocated when executing the module's body.
m_functionsToInitialize.append(std::make_pair(function, NormalFunctionVariable));
}
}
// Remember the constant register offset to the top-most symbol table. This symbol table will be
// cloned in the code block linking. After that, to create the module environment, we retrieve
// the cloned symbol table from the linked code block by using this offset.
codeBlock->setModuleEnvironmentSymbolTableConstantRegisterOffset(constantSymbolTable->index());
}
BytecodeGenerator::~BytecodeGenerator()
{
}
void BytecodeGenerator::initializeDefaultParameterValuesAndSetupFunctionScopeStack(
FunctionParameters& parameters, bool isSimpleParameterList, FunctionNode* functionNode, SymbolTable* functionSymbolTable,
int symbolTableConstantIndex, const ScopedLambda<bool (UniquedStringImpl*)>& captures, bool shouldCreateArgumentsVariableInParameterScope)
{
Vector<std::pair<Identifier, RefPtr<RegisterID>>> valuesToMoveIntoVars;
ASSERT(!(isSimpleParameterList && shouldCreateArgumentsVariableInParameterScope));
if (!isSimpleParameterList) {
// Refer to the ES6 spec section 9.2.12: http://www.ecma-international.org/ecma-262/6.0/index.html#sec-functiondeclarationinstantiation
// This implements step 21.
VariableEnvironment environment;
Vector<Identifier> allParameterNames;
for (unsigned i = 0; i < parameters.size(); i++)
parameters.at(i).first->collectBoundIdentifiers(allParameterNames);
if (shouldCreateArgumentsVariableInParameterScope)
allParameterNames.append(propertyNames().arguments);
IdentifierSet parameterSet;
for (auto& ident : allParameterNames) {
parameterSet.add(ident.impl());
auto addResult = environment.add(ident);
addResult.iterator->value.setIsLet(); // When we have default parameter expressions, parameters act like "let" variables.
if (captures(ident.impl()))
addResult.iterator->value.setIsCaptured();
}
// This implements step 25 of section 9.2.12.
pushLexicalScopeInternal(environment, TDZCheckOptimization::Optimize, NestedScopeType::IsNotNested, nullptr, TDZRequirement::UnderTDZ, ScopeType::LetConstScope, ScopeRegisterType::Block);
if (shouldCreateArgumentsVariableInParameterScope) {
Variable argumentsVariable = variable(propertyNames().arguments);
initializeVariable(argumentsVariable, m_argumentsRegister);
liftTDZCheckIfPossible(argumentsVariable);
}
RefPtr<RegisterID> temp = newTemporary();
for (unsigned i = 0; i < parameters.size(); i++) {
std::pair<DestructuringPatternNode*, ExpressionNode*> parameter = parameters.at(i);
if (parameter.first->isRestParameter())
continue;
if ((i + 1) < m_parameters.size())
move(temp.get(), &m_parameters[i + 1]);
else
emitGetArgument(temp.get(), i);
if (parameter.second) {
RefPtr<RegisterID> condition = emitIsUndefined(newTemporary(), temp.get());
Ref<Label> skipDefaultParameterBecauseNotUndefined = newLabel();
emitJumpIfFalse(condition.get(), skipDefaultParameterBecauseNotUndefined.get());
emitNode(temp.get(), parameter.second);
emitLabel(skipDefaultParameterBecauseNotUndefined.get());
}
parameter.first->bindValue(*this, temp.get());
}
// Final act of weirdness for default parameters. If a "var" also
// has the same name as a parameter, it should start out as the
// value of that parameter. Note, though, that they will be distinct
// bindings.
// This is step 28 of section 9.2.12.
for (auto& entry : functionNode->varDeclarations()) {
if (!entry.value.isVar()) // This is either a parameter or callee.
continue;
if (parameterSet.contains(entry.key)) {
Identifier ident = Identifier::fromUid(m_vm, entry.key.get());
Variable var = variable(ident);
RegisterID* scope = emitResolveScope(nullptr, var);
RefPtr<RegisterID> value = emitGetFromScope(newTemporary(), scope, var, DoNotThrowIfNotFound);
valuesToMoveIntoVars.append(std::make_pair(ident, value));
}
}
// Functions with default parameter expressions must have a separate environment
// record for parameters and "var"s. The "var" environment record must have the
// parameter environment record as its parent.
// See step 28 of section 9.2.12.
bool hasCapturedVariables = !!m_lexicalEnvironmentRegister;
initializeVarLexicalEnvironment(symbolTableConstantIndex, functionSymbolTable, hasCapturedVariables);
}
// This completes step 28 of section 9.2.12.
for (unsigned i = 0; i < valuesToMoveIntoVars.size(); i++) {
ASSERT(!isSimpleParameterList);
Variable var = variable(valuesToMoveIntoVars[i].first);
RegisterID* scope = emitResolveScope(nullptr, var);
emitPutToScope(scope, var, valuesToMoveIntoVars[i].second.get(), DoNotThrowIfNotFound, InitializationMode::NotInitialization);
}
}
bool BytecodeGenerator::needsDerivedConstructorInArrowFunctionLexicalEnvironment()
{
ASSERT(m_codeBlock->isClassContext() || !(isConstructor() && constructorKind() == ConstructorKind::Extends));
return m_codeBlock->isClassContext() && isSuperUsedInInnerArrowFunction();
}
void BytecodeGenerator::initializeArrowFunctionContextScopeIfNeeded(SymbolTable* functionSymbolTable, bool canReuseLexicalEnvironment)
{
ASSERT(!m_arrowFunctionContextLexicalEnvironmentRegister);
if (canReuseLexicalEnvironment && m_lexicalEnvironmentRegister) {
RELEASE_ASSERT(!m_codeBlock->isArrowFunction());
RELEASE_ASSERT(functionSymbolTable);
m_arrowFunctionContextLexicalEnvironmentRegister = m_lexicalEnvironmentRegister;
ScopeOffset offset;
if (isThisUsedInInnerArrowFunction()) {
offset = functionSymbolTable->takeNextScopeOffset(NoLockingNecessary);
functionSymbolTable->set(NoLockingNecessary, propertyNames().thisIdentifier.impl(), SymbolTableEntry(VarOffset(offset)));
}
if (m_codeType == FunctionCode && isNewTargetUsedInInnerArrowFunction()) {
offset = functionSymbolTable->takeNextScopeOffset();
functionSymbolTable->set(NoLockingNecessary, propertyNames().builtinNames().newTargetLocalPrivateName().impl(), SymbolTableEntry(VarOffset(offset)));
}
if (needsDerivedConstructorInArrowFunctionLexicalEnvironment()) {
offset = functionSymbolTable->takeNextScopeOffset(NoLockingNecessary);
functionSymbolTable->set(NoLockingNecessary, propertyNames().builtinNames().derivedConstructorPrivateName().impl(), SymbolTableEntry(VarOffset(offset)));
}
return;
}
VariableEnvironment environment;
if (isThisUsedInInnerArrowFunction()) {
auto addResult = environment.add(propertyNames().thisIdentifier);
addResult.iterator->value.setIsCaptured();
addResult.iterator->value.setIsLet();
}
if (m_codeType == FunctionCode && isNewTargetUsedInInnerArrowFunction()) {
auto addTarget = environment.add(propertyNames().builtinNames().newTargetLocalPrivateName());
addTarget.iterator->value.setIsCaptured();
addTarget.iterator->value.setIsLet();
}
if (needsDerivedConstructorInArrowFunctionLexicalEnvironment()) {
auto derivedConstructor = environment.add(propertyNames().builtinNames().derivedConstructorPrivateName());
derivedConstructor.iterator->value.setIsCaptured();
derivedConstructor.iterator->value.setIsLet();
}
if (environment.size() > 0) {
size_t size = m_lexicalScopeStack.size();
pushLexicalScopeInternal(environment, TDZCheckOptimization::Optimize, NestedScopeType::IsNotNested, nullptr, TDZRequirement::UnderTDZ, ScopeType::LetConstScope, ScopeRegisterType::Block);
ASSERT_UNUSED(size, m_lexicalScopeStack.size() == size + 1);
m_arrowFunctionContextLexicalEnvironmentRegister = m_lexicalScopeStack.last().m_scope;
}
}
RegisterID* BytecodeGenerator::initializeNextParameter()
{
VirtualRegister reg = virtualRegisterForArgument(m_codeBlock->numParameters());
m_parameters.grow(m_parameters.size() + 1);
auto& parameter = registerFor(reg);
parameter.setIndex(reg);
m_codeBlock->addParameter();
return &parameter;
}
void BytecodeGenerator::initializeParameters(FunctionParameters& parameters)
{
// Make sure the code block knows about all of our parameters, and make sure that parameters
// needing destructuring are noted.
m_thisRegister.setIndex(VirtualRegister(initializeNextParameter()->index())); // this
bool nonSimpleArguments = false;
for (unsigned i = 0; i < parameters.size(); ++i) {
auto parameter = parameters.at(i);
auto pattern = parameter.first;
if (pattern->isRestParameter()) {
RELEASE_ASSERT(!m_restParameter);
m_restParameter = static_cast<RestParameterNode*>(pattern);
nonSimpleArguments = true;
continue;
}
if (parameter.second) {
nonSimpleArguments = true;
continue;
}
if (!nonSimpleArguments)
initializeNextParameter();
}
}
void BytecodeGenerator::initializeVarLexicalEnvironment(int symbolTableConstantIndex, SymbolTable* functionSymbolTable, bool hasCapturedVariables)
{
if (hasCapturedVariables) {
RELEASE_ASSERT(m_lexicalEnvironmentRegister);
OpCreateLexicalEnvironment::emit(this, m_lexicalEnvironmentRegister, scopeRegister(), VirtualRegister { symbolTableConstantIndex }, addConstantValue(jsUndefined()));
OpMov::emit(this, scopeRegister(), m_lexicalEnvironmentRegister);
pushLocalControlFlowScope();
}
bool isWithScope = false;
m_lexicalScopeStack.append({ functionSymbolTable, m_lexicalEnvironmentRegister, isWithScope, symbolTableConstantIndex });
m_varScopeLexicalScopeStackIndex = m_lexicalScopeStack.size() - 1;
}
UniquedStringImpl* BytecodeGenerator::visibleNameForParameter(DestructuringPatternNode* pattern)
{
if (pattern->isBindingNode()) {
const Identifier& ident = static_cast<const BindingNode*>(pattern)->boundProperty();
if (!m_functions.contains(ident.impl()))
return ident.impl();
}
return nullptr;
}
RegisterID* BytecodeGenerator::newBlockScopeVariable()
{
reclaimFreeRegisters();
return newRegister();
}
Ref<LabelScope> BytecodeGenerator::newLabelScope(LabelScope::Type type, const Identifier* name)
{
shrinkToFit(m_labelScopes);
// Allocate new label scope.
m_labelScopes.append(type, name, labelScopeDepth(), newLabel(), type == LabelScope::Loop ? RefPtr<Label>(newLabel()) : RefPtr<Label>()); // Only loops have continue targets.
return m_labelScopes.last();
}
void BytecodeGenerator::emitEnter()
{
OpEnter::emit(this);
if (LIKELY(Options::optimizeRecursiveTailCalls())) {
// We must add the end of op_enter as a potential jump target, because the bytecode parser may decide to split its basic block
// to have somewhere to jump to if there is a recursive tail-call that points to this function.
m_codeBlock->addJumpTarget(instructions().size());
// This disables peephole optimizations when an instruction is a jump target
m_lastOpcodeID = op_end;
}
}
void BytecodeGenerator::emitLoopHint()
{
OpLoopHint::emit(this);
emitCheckTraps();
}
void BytecodeGenerator::emitJump(Label& target)
{
OpJmp::emit(this, target.bind(this));
}
void BytecodeGenerator::emitCheckTraps()
{
OpCheckTraps::emit(this);
}
void ALWAYS_INLINE BytecodeGenerator::rewind()
{
ASSERT(m_lastInstruction.isValid());
m_lastOpcodeID = op_end;
m_writer.rewind(m_lastInstruction);
}
template<typename BinOp, typename JmpOp>
bool BytecodeGenerator::fuseCompareAndJump(RegisterID* cond, Label& target, bool swapOperands)
{
ASSERT(canDoPeepholeOptimization());
auto binop = m_lastInstruction->as<BinOp>();
if (cond->index() == binop.m_dst.offset() && cond->isTemporary() && !cond->refCount()) {
rewind();
if (swapOperands)
std::swap(binop.m_lhs, binop.m_rhs);
JmpOp::emit(this, binop.m_lhs, binop.m_rhs, target.bind(this));
return true;
}
return false;
}
template<typename UnaryOp, typename JmpOp>
bool BytecodeGenerator::fuseTestAndJmp(RegisterID* cond, Label& target)
{
ASSERT(canDoPeepholeOptimization());
auto unop = m_lastInstruction->as<UnaryOp>();
if (cond->index() == unop.m_dst.offset() && cond->isTemporary() && !cond->refCount()) {
rewind();
JmpOp::emit(this, unop.m_operand, target.bind(this));
return true;
}
return false;
}
void BytecodeGenerator::emitJumpIfTrue(RegisterID* cond, Label& target)
{
if (canDoPeepholeOptimization()) {
if (m_lastOpcodeID == op_less) {
if (fuseCompareAndJump<OpLess, OpJless>(cond, target))
return;
} else if (m_lastOpcodeID == op_lesseq) {
if (fuseCompareAndJump<OpLesseq, OpJlesseq>(cond, target))
return;
} else if (m_lastOpcodeID == op_greater) {
if (fuseCompareAndJump<OpGreater, OpJgreater>(cond, target))
return;
} else if (m_lastOpcodeID == op_greatereq) {
if (fuseCompareAndJump<OpGreatereq, OpJgreatereq>(cond, target))
return;
} else if (m_lastOpcodeID == op_eq) {
if (fuseCompareAndJump<OpEq, OpJeq>(cond, target))
return;
} else if (m_lastOpcodeID == op_stricteq) {
if (fuseCompareAndJump<OpStricteq, OpJstricteq>(cond, target))
return;
} else if (m_lastOpcodeID == op_neq) {
if (fuseCompareAndJump<OpNeq, OpJneq>(cond, target))
return;
} else if (m_lastOpcodeID == op_nstricteq) {
if (fuseCompareAndJump<OpNstricteq, OpJnstricteq>(cond, target))
return;
} else if (m_lastOpcodeID == op_below) {
if (fuseCompareAndJump<OpBelow, OpJbelow>(cond, target))
return;
} else if (m_lastOpcodeID == op_beloweq) {
if (fuseCompareAndJump<OpBeloweq, OpJbeloweq>(cond, target))
return;
} else if (m_lastOpcodeID == op_eq_null && target.isForward()) {
if (fuseTestAndJmp<OpEqNull, OpJeqNull>(cond, target))
return;
} else if (m_lastOpcodeID == op_neq_null && target.isForward()) {
if (fuseTestAndJmp<OpNeqNull, OpJneqNull>(cond, target))
return;
} else if (m_lastOpcodeID == op_is_undefined_or_null && target.isForward()) {
if (fuseTestAndJmp<OpIsUndefinedOrNull, OpJundefinedOrNull>(cond, target))
return;
}
}
OpJtrue::emit(this, cond, target.bind(this));
}
void BytecodeGenerator::emitJumpIfFalse(RegisterID* cond, Label& target)
{
if (canDoPeepholeOptimization()) {
if (m_lastOpcodeID == op_less && target.isForward()) {
if (fuseCompareAndJump<OpLess, OpJnless>(cond, target))
return;
} else if (m_lastOpcodeID == op_lesseq && target.isForward()) {
if (fuseCompareAndJump<OpLesseq, OpJnlesseq>(cond, target))
return;
} else if (m_lastOpcodeID == op_greater && target.isForward()) {
if (fuseCompareAndJump<OpGreater, OpJngreater>(cond, target))
return;
} else if (m_lastOpcodeID == op_greatereq && target.isForward()) {
if (fuseCompareAndJump<OpGreatereq, OpJngreatereq>(cond, target))
return;
} else if (m_lastOpcodeID == op_eq && target.isForward()) {
if (fuseCompareAndJump<OpEq, OpJneq>(cond, target))
return;
} else if (m_lastOpcodeID == op_stricteq && target.isForward()) {
if (fuseCompareAndJump<OpStricteq, OpJnstricteq>(cond, target))
return;
} else if (m_lastOpcodeID == op_neq && target.isForward()) {
if (fuseCompareAndJump<OpNeq, OpJeq>(cond, target))
return;
} else if (m_lastOpcodeID == op_nstricteq && target.isForward()) {
if (fuseCompareAndJump<OpNstricteq, OpJstricteq>(cond, target))
return;
} else if (m_lastOpcodeID == op_below && target.isForward()) {
if (fuseCompareAndJump<OpBelow, OpJbeloweq>(cond, target, true))
return;
} else if (m_lastOpcodeID == op_beloweq && target.isForward()) {
if (fuseCompareAndJump<OpBeloweq, OpJbelow>(cond, target, true))
return;
} else if (m_lastOpcodeID == op_not) {
if (fuseTestAndJmp<OpNot, OpJtrue>(cond, target))
return;
} else if (m_lastOpcodeID == op_eq_null && target.isForward()) {
if (fuseTestAndJmp<OpEqNull, OpJneqNull>(cond, target))
return;
} else if (m_lastOpcodeID == op_neq_null && target.isForward()) {
if (fuseTestAndJmp<OpNeqNull, OpJeqNull>(cond, target))
return;
} else if (m_lastOpcodeID == op_is_undefined_or_null && target.isForward()) {
if (fuseTestAndJmp<OpIsUndefinedOrNull, OpJnundefinedOrNull>(cond, target))
return;
}
}
OpJfalse::emit(this, cond, target.bind(this));
}
void BytecodeGenerator::emitJumpIfNotFunctionCall(RegisterID* cond, Label& target)
{
OpJneqPtr::emit(this, cond, moveLinkTimeConstant(nullptr, LinkTimeConstant::callFunction), target.bind(this));
}
void BytecodeGenerator::emitJumpIfNotFunctionApply(RegisterID* cond, Label& target)
{
OpJneqPtr::emit(this, cond, moveLinkTimeConstant(nullptr, LinkTimeConstant::applyFunction), target.bind(this));
}
bool BytecodeGenerator::hasConstant(const Identifier& ident) const
{
UniquedStringImpl* rep = ident.impl();
return m_identifierMap.contains(rep);
}
unsigned BytecodeGenerator::addConstant(const Identifier& ident)
{
UniquedStringImpl* rep = ident.impl();
IdentifierMap::AddResult result = m_identifierMap.add(rep, m_codeBlock->numberOfIdentifiers());
if (result.isNewEntry)
m_codeBlock->addIdentifier(ident);
return result.iterator->value;
}
// We can't hash JSValue(), so we use a dedicated data member to cache it.
RegisterID* BytecodeGenerator::addConstantEmptyValue()
{
if (!m_emptyValueRegister) {
int index = addConstantIndex();
m_codeBlock->addConstant(JSValue());
m_emptyValueRegister = &m_constantPoolRegisters[index];
}
return m_emptyValueRegister;
}
RegisterID* BytecodeGenerator::addConstantValue(JSValue v, SourceCodeRepresentation sourceCodeRepresentation)
{
if (!v)
return addConstantEmptyValue();
int index = m_nextConstantOffset;
if (sourceCodeRepresentation == SourceCodeRepresentation::Double && v.isInt32())
v = jsDoubleNumber(v.asNumber());
EncodedJSValueWithRepresentation valueMapKey { JSValue::encode(v), sourceCodeRepresentation };
JSValueMap::AddResult result = m_jsValueMap.add(valueMapKey, m_nextConstantOffset);
if (result.isNewEntry) {
addConstantIndex();
m_codeBlock->addConstant(v, sourceCodeRepresentation);
} else
index = result.iterator->value;
return &m_constantPoolRegisters[index];
}
RegisterID* BytecodeGenerator::moveLinkTimeConstant(RegisterID* dst, LinkTimeConstant type)
{
RegisterID* constant = m_linkTimeConstantRegisters.ensure(type, [&] {
int index = addConstantIndex();
m_codeBlock->addConstant(type);
return &m_constantPoolRegisters[index];
}).iterator->value;
if (!dst)
return constant;
OpMov::emit(this, dst, constant);
return dst;
}
RegisterID* BytecodeGenerator::moveEmptyValue(RegisterID* dst)
{
RefPtr<RegisterID> emptyValue = addConstantEmptyValue();
OpMov::emit(this, dst, emptyValue.get());
return dst;
}
RegisterID* BytecodeGenerator::emitMove(RegisterID* dst, RegisterID* src)
{
ASSERT(src != m_emptyValueRegister);
m_staticPropertyAnalyzer.mov(dst, src);
OpMov::emit(this, dst, src);
return dst;
}
RegisterID* BytecodeGenerator::emitUnaryOp(OpcodeID opcodeID, RegisterID* dst, RegisterID* src, ResultType type)
{
switch (opcodeID) {
case op_not:
emitUnaryOp<OpNot>(dst, src);
break;
case op_negate:
OpNegate::emit(this, dst, src, type);
break;
case op_bitnot:
emitUnaryOp<OpBitnot>(dst, src);
break;
case op_to_number:
emitUnaryOp<OpToNumber>(dst, src);
break;
case op_to_numeric:
emitUnaryOp<OpToNumeric>(dst, src);
break;
default:
ASSERT_NOT_REACHED();
}
return dst;
}
RegisterID* BytecodeGenerator::emitBinaryOp(OpcodeID opcodeID, RegisterID* dst, RegisterID* src1, RegisterID* src2, OperandTypes types)
{
switch (opcodeID) {
case op_eq:
return emitBinaryOp<OpEq>(dst, src1, src2, types);
case op_neq:
return emitBinaryOp<OpNeq>(dst, src1, src2, types);
case op_stricteq:
return emitBinaryOp<OpStricteq>(dst, src1, src2, types);
case op_nstricteq:
return emitBinaryOp<OpNstricteq>(dst, src1, src2, types);
case op_less:
return emitBinaryOp<OpLess>(dst, src1, src2, types);
case op_lesseq:
return emitBinaryOp<OpLesseq>(dst, src1, src2, types);
case op_greater:
return emitBinaryOp<OpGreater>(dst, src1, src2, types);
case op_greatereq:
return emitBinaryOp<OpGreatereq>(dst, src1, src2, types);
case op_below:
return emitBinaryOp<OpBelow>(dst, src1, src2, types);
case op_beloweq:
return emitBinaryOp<OpBeloweq>(dst, src1, src2, types);
case op_mod:
return emitBinaryOp<OpMod>(dst, src1, src2, types);
case op_pow:
return emitBinaryOp<OpPow>(dst, src1, src2, types);
case op_lshift:
return emitBinaryOp<OpLshift>(dst, src1, src2, types);
case op_rshift:
return emitBinaryOp<OpRshift>(dst, src1, src2, types);
case op_urshift:
return emitBinaryOp<OpUrshift>(dst, src1, src2, types);
case op_add:
return emitBinaryOp<OpAdd>(dst, src1, src2, types);
case op_mul:
return emitBinaryOp<OpMul>(dst, src1, src2, types);
case op_div:
return emitBinaryOp<OpDiv>(dst, src1, src2, types);
case op_sub:
return emitBinaryOp<OpSub>(dst, src1, src2, types);
case op_bitand:
return emitBinaryOp<OpBitand>(dst, src1, src2, types);
case op_bitxor:
return emitBinaryOp<OpBitxor>(dst, src1, src2, types);
case op_bitor:
return emitBinaryOp<OpBitor>(dst, src1, src2, types);
default:
ASSERT_NOT_REACHED();
return nullptr;
}
}
RegisterID* BytecodeGenerator::emitToObject(RegisterID* dst, RegisterID* src, const Identifier& message)
{
OpToObject::emit(this, dst, src, addConstant(message));
return dst;
}
RegisterID* BytecodeGenerator::emitToNumber(RegisterID* dst, RegisterID* src)
{
return emitUnaryOp<OpToNumber>(dst, src);
}
RegisterID* BytecodeGenerator::emitToNumeric(RegisterID* dst, RegisterID* src)
{
return emitUnaryOp<OpToNumeric>(dst, src);
}
RegisterID* BytecodeGenerator::emitToString(RegisterID* dst, RegisterID* src)
{
return emitUnaryOp<OpToString>(dst, src);
}
RegisterID* BytecodeGenerator::emitTypeOf(RegisterID* dst, RegisterID* src)
{
return emitUnaryOp<OpTypeof>(dst, src);
}
RegisterID* BytecodeGenerator::emitInc(RegisterID* srcDst)
{
OpInc::emit(this, srcDst);
return srcDst;
}
RegisterID* BytecodeGenerator::emitDec(RegisterID* srcDst)
{
OpDec::emit(this, srcDst);
return srcDst;
}
bool BytecodeGenerator::emitEqualityOpImpl(RegisterID* dst, RegisterID* src1, RegisterID* src2)
{
if (!canDoPeepholeOptimization())
return false;
if (m_lastInstruction->is<OpTypeof>()) {
auto op = m_lastInstruction->as<OpTypeof>();
if (src1->virtualRegister() == op.m_dst
&& src1->isTemporary()
&& src2->virtualRegister().isConstant()
&& m_codeBlock->constantRegister(src2->virtualRegister()).get().isString()) {
const String& value = asString(m_codeBlock->constantRegister(src2->virtualRegister()).get())->tryGetValue();
if (value == "undefined") {
rewind();
OpIsUndefined::emit(this, dst, op.m_value);
return true;
}
if (value == "boolean") {
rewind();
OpIsBoolean::emit(this, dst, op.m_value);
return true;
}
if (value == "number") {
rewind();
OpIsNumber::emit(this, dst, op.m_value);
return true;
}
if (value == "string") {
rewind();
OpIsCellWithType::emit(this, dst, op.m_value, StringType);
return true;
}
if (value == "symbol") {
rewind();
OpIsCellWithType::emit(this, dst, op.m_value, SymbolType);
return true;
}
if (Options::useBigInt() && value == "bigint") {
rewind();
OpIsCellWithType::emit(this, dst, op.m_value, BigIntType);
return true;
}
if (value == "object") {
rewind();
OpIsObjectOrNull::emit(this, dst, op.m_value);
return true;
}
if (value == "function") {
rewind();
OpIsFunction::emit(this, dst, op.m_value);
return true;
}
}
}
return false;
}
void BytecodeGenerator::emitTypeProfilerExpressionInfo(const JSTextPosition& startDivot, const JSTextPosition& endDivot)
{
ASSERT(shouldEmitTypeProfilerHooks());
unsigned start = startDivot.offset; // Ranges are inclusive of their endpoints, AND 0 indexed.
unsigned end = endDivot.offset - 1; // End Ranges already go one past the inclusive range, so subtract 1.
unsigned instructionOffset = instructions().size() - 1;
m_codeBlock->addTypeProfilerExpressionInfo(instructionOffset, start, end);
}
void BytecodeGenerator::emitProfileType(RegisterID* registerToProfile, ProfileTypeBytecodeFlag flag)
{
if (!shouldEmitTypeProfilerHooks())
return;
if (!registerToProfile)
return;
OpProfileType::emit(this, registerToProfile, { }, flag, { }, resolveType());
// Don't emit expression info for this version of profile type. This generally means
// we're profiling information for something that isn't in the actual text of a JavaScript
// program. For example, implicit return undefined from a function call.
}
void BytecodeGenerator::emitProfileType(RegisterID* registerToProfile, const JSTextPosition& startDivot, const JSTextPosition& endDivot)
{
emitProfileType(registerToProfile, ProfileTypeBytecodeDoesNotHaveGlobalID, startDivot, endDivot);
}
void BytecodeGenerator::emitProfileType(RegisterID* registerToProfile, ProfileTypeBytecodeFlag flag, const JSTextPosition& startDivot, const JSTextPosition& endDivot)
{
if (!shouldEmitTypeProfilerHooks())
return;
if (!registerToProfile)
return;
OpProfileType::emit(this, registerToProfile, { }, flag, { }, resolveType());
emitTypeProfilerExpressionInfo(startDivot, endDivot);
}
void BytecodeGenerator::emitProfileType(RegisterID* registerToProfile, const Variable& var, const JSTextPosition& startDivot, const JSTextPosition& endDivot)
{
if (!shouldEmitTypeProfilerHooks())
return;
if (!registerToProfile)
return;
ProfileTypeBytecodeFlag flag;
SymbolTableOrScopeDepth symbolTableOrScopeDepth;
if (var.local() || var.offset().isScope()) {
flag = ProfileTypeBytecodeLocallyResolved;
ASSERT(var.symbolTableConstantIndex());
symbolTableOrScopeDepth = SymbolTableOrScopeDepth::symbolTable(VirtualRegister { var.symbolTableConstantIndex() });
} else {
flag = ProfileTypeBytecodeClosureVar;
symbolTableOrScopeDepth = SymbolTableOrScopeDepth::scopeDepth(localScopeDepth());
}
OpProfileType::emit(this, registerToProfile, symbolTableOrScopeDepth, flag, addConstant(var.ident()), resolveType());
emitTypeProfilerExpressionInfo(startDivot, endDivot);
}
void BytecodeGenerator::emitProfileControlFlow(int textOffset)
{
if (shouldEmitControlFlowProfilerHooks()) {
RELEASE_ASSERT(textOffset >= 0);
OpProfileControlFlow::emit(this, textOffset);
m_codeBlock->addOpProfileControlFlowBytecodeOffset(m_lastInstruction.offset());
}
}
unsigned BytecodeGenerator::addConstantIndex()
{
unsigned index = m_nextConstantOffset;
m_constantPoolRegisters.append(FirstConstantRegisterIndex + m_nextConstantOffset);
++m_nextConstantOffset;
return index;
}
RegisterID* BytecodeGenerator::emitLoad(RegisterID* dst, bool b)
{
return emitLoad(dst, jsBoolean(b));
}
RegisterID* BytecodeGenerator::emitLoad(RegisterID* dst, const Identifier& identifier)
{
ASSERT(!identifier.isSymbol());
JSString*& stringInMap = m_stringMap.add(identifier.impl(), nullptr).iterator->value;
if (!stringInMap)
stringInMap = jsOwnedString(vm(), identifier.string());
return emitLoad(dst, JSValue(stringInMap));
}
RegisterID* BytecodeGenerator::emitLoad(RegisterID* dst, JSValue v, SourceCodeRepresentation sourceCodeRepresentation)
{
RegisterID* constantID = addConstantValue(v, sourceCodeRepresentation);
if (dst)
return move(dst, constantID);
return constantID;
}
RegisterID* BytecodeGenerator::emitLoad(RegisterID* dst, IdentifierSet& set)
{
if (m_codeBlock->numberOfConstantIdentifierSets()) {
for (const auto& entry : m_codeBlock->constantIdentifierSets()) {
if (entry.first != set)
continue;
return &m_constantPoolRegisters[entry.second];
}
}
unsigned index = addConstantIndex();
m_codeBlock->addSetConstant(set);
RegisterID* m_setRegister = &m_constantPoolRegisters[index];
if (dst)
return move(dst, m_setRegister);
return m_setRegister;
}
template<typename LookUpVarKindFunctor>
bool BytecodeGenerator::instantiateLexicalVariables(const VariableEnvironment& lexicalVariables, SymbolTable* symbolTable, ScopeRegisterType scopeRegisterType, LookUpVarKindFunctor lookUpVarKind)
{
bool hasCapturedVariables = false;
{
for (auto& entry : lexicalVariables) {
ASSERT(entry.value.isLet() || entry.value.isConst() || entry.value.isFunction());
ASSERT(!entry.value.isVar());
SymbolTableEntry symbolTableEntry = symbolTable->get(NoLockingNecessary, entry.key.get());
ASSERT(symbolTableEntry.isNull());
// Imported bindings which are not the namespace bindings are not allocated
// in the module environment as usual variables' way.
// And since these types of the variables only seen in the module environment,
// other lexical environment need not to take care this.
if (entry.value.isImported() && !entry.value.isImportedNamespace())
continue;
VarKind varKind = lookUpVarKind(entry.key.get(), entry.value);
VarOffset varOffset;
if (varKind == VarKind::Scope) {
varOffset = VarOffset(symbolTable->takeNextScopeOffset(NoLockingNecessary));
hasCapturedVariables = true;
} else {
ASSERT(varKind == VarKind::Stack);
RegisterID* local;
if (scopeRegisterType == ScopeRegisterType::Block) {
local = newBlockScopeVariable();
local->ref();
} else
local = addVar();
varOffset = VarOffset(local->virtualRegister());
}
SymbolTableEntry newEntry(varOffset, static_cast<unsigned>(entry.value.isConst() ? PropertyAttribute::ReadOnly : PropertyAttribute::None));
symbolTable->add(NoLockingNecessary, entry.key.get(), newEntry);
}
}
return hasCapturedVariables;
}
void BytecodeGenerator::emitPrefillStackTDZVariables(const VariableEnvironment& lexicalVariables, SymbolTable* symbolTable)
{
// Prefill stack variables with the TDZ empty value.
// Scope variables will be initialized to the TDZ empty value when JSLexicalEnvironment is allocated.
for (auto& entry : lexicalVariables) {
// Imported bindings which are not the namespace bindings are not allocated
// in the module environment as usual variables' way.
// And since these types of the variables only seen in the module environment,
// other lexical environment need not to take care this.
if (entry.value.isImported() && !entry.value.isImportedNamespace())
continue;
if (entry.value.isFunction())
continue;
SymbolTableEntry symbolTableEntry = symbolTable->get(NoLockingNecessary, entry.key.get());
ASSERT(!symbolTableEntry.isNull());
VarOffset offset = symbolTableEntry.varOffset();
if (offset.isScope())
continue;
ASSERT(offset.isStack());
moveEmptyValue(&registerFor(offset.stackOffset()));
}
}
void BytecodeGenerator::pushLexicalScope(VariableEnvironmentNode* node, TDZCheckOptimization tdzCheckOptimization, NestedScopeType nestedScopeType, RegisterID** constantSymbolTableResult, bool shouldInitializeBlockScopedFunctions)
{
VariableEnvironment& environment = node->lexicalVariables();
RegisterID* constantSymbolTableResultTemp = nullptr;
pushLexicalScopeInternal(environment, tdzCheckOptimization, nestedScopeType, &constantSymbolTableResultTemp, TDZRequirement::UnderTDZ, ScopeType::LetConstScope, ScopeRegisterType::Block);
if (shouldInitializeBlockScopedFunctions)
initializeBlockScopedFunctions(environment, node->functionStack(), constantSymbolTableResultTemp);
if (constantSymbolTableResult && constantSymbolTableResultTemp)
*constantSymbolTableResult = constantSymbolTableResultTemp;
}
void BytecodeGenerator::pushLexicalScopeInternal(VariableEnvironment& environment, TDZCheckOptimization tdzCheckOptimization, NestedScopeType nestedScopeType,
RegisterID** constantSymbolTableResult, TDZRequirement tdzRequirement, ScopeType scopeType, ScopeRegisterType scopeRegisterType)
{
if (!environment.size())
return;
if (shouldEmitDebugHooks())
environment.markAllVariablesAsCaptured();
SymbolTable* symbolTable = SymbolTable::create(m_vm);
switch (scopeType) {
case ScopeType::CatchScope:
symbolTable->setScopeType(SymbolTable::ScopeType::CatchScope);
break;
case ScopeType::LetConstScope:
symbolTable->setScopeType(SymbolTable::ScopeType::LexicalScope);
break;
case ScopeType::FunctionNameScope:
symbolTable->setScopeType(SymbolTable::ScopeType::FunctionNameScope);
break;
}
if (nestedScopeType == NestedScopeType::IsNested)
symbolTable->markIsNestedLexicalScope();
auto lookUpVarKind = [] (UniquedStringImpl*, const VariableEnvironmentEntry& entry) -> VarKind {
return entry.isCaptured() ? VarKind::Scope : VarKind::Stack;
};
bool hasCapturedVariables = instantiateLexicalVariables(environment, symbolTable, scopeRegisterType, lookUpVarKind);
RegisterID* newScope = nullptr;
RegisterID* constantSymbolTable = nullptr;
int symbolTableConstantIndex = 0;
if (shouldEmitTypeProfilerHooks()) {
constantSymbolTable = addConstantValue(symbolTable);
symbolTableConstantIndex = constantSymbolTable->index();
}
if (hasCapturedVariables) {
if (scopeRegisterType == ScopeRegisterType::Block) {
newScope = newBlockScopeVariable();
newScope->ref();
} else
newScope = addVar();
if (!constantSymbolTable) {
ASSERT(!shouldEmitTypeProfilerHooks());
constantSymbolTable = addConstantValue(symbolTable->cloneScopePart(m_vm));
symbolTableConstantIndex = constantSymbolTable->index();
}
if (constantSymbolTableResult)
*constantSymbolTableResult = constantSymbolTable;
OpCreateLexicalEnvironment::emit(this, newScope, scopeRegister(), VirtualRegister { symbolTableConstantIndex }, addConstantValue(tdzRequirement == TDZRequirement::UnderTDZ ? jsTDZValue() : jsUndefined()));
move(scopeRegister(), newScope);
pushLocalControlFlowScope();
}
bool isWithScope = false;
m_lexicalScopeStack.append({ symbolTable, newScope, isWithScope, symbolTableConstantIndex });
pushTDZVariables(environment, tdzCheckOptimization, tdzRequirement);
if (tdzRequirement == TDZRequirement::UnderTDZ)
emitPrefillStackTDZVariables(environment, symbolTable);
}
void BytecodeGenerator::initializeBlockScopedFunctions(VariableEnvironment& environment, FunctionStack& functionStack, RegisterID* constantSymbolTable)
{
/*
* We must transform block scoped function declarations in strict mode like so:
*
* function foo() {
* if (c) {
* function foo() { ... }
* if (bar) { ... }
* else { ... }
* function baz() { ... }
* }
* }
*
* to:
*
* function foo() {
* if (c) {
* let foo = function foo() { ... }
* let baz = function baz() { ... }
* if (bar) { ... }
* else { ... }
* }
* }
*
* But without the TDZ checks.
*/
if (!environment.size()) {
RELEASE_ASSERT(!functionStack.size());
return;
}
if (!functionStack.size())
return;
SymbolTable* symbolTable = m_lexicalScopeStack.last().m_symbolTable;
RegisterID* scope = m_lexicalScopeStack.last().m_scope;
RefPtr<RegisterID> temp = newTemporary();
int symbolTableIndex = constantSymbolTable ? constantSymbolTable->index() : 0;
for (FunctionMetadataNode* function : functionStack) {
const Identifier& name = function->ident();
auto iter = environment.find(name.impl());
RELEASE_ASSERT(iter != environment.end());
RELEASE_ASSERT(iter->value.isFunction());
// We purposefully don't hold the symbol table lock around this loop because emitNewFunctionExpressionCommon may GC.
SymbolTableEntry entry = symbolTable->get(NoLockingNecessary, name.impl());
RELEASE_ASSERT(!entry.isNull());
emitNewFunctionExpressionCommon(temp.get(), function);
bool isLexicallyScoped = true;
emitPutToScope(scope, variableForLocalEntry(name, entry, symbolTableIndex, isLexicallyScoped), temp.get(), DoNotThrowIfNotFound, InitializationMode::Initialization);
}
}
void BytecodeGenerator::hoistSloppyModeFunctionIfNecessary(const Identifier& functionName)
{
if (m_scopeNode->hasSloppyModeHoistedFunction(functionName.impl())) {
if (codeType() != EvalCode) {
Variable currentFunctionVariable = variable(functionName);
RefPtr<RegisterID> currentValue;
if (RegisterID* local = currentFunctionVariable.local())
currentValue = local;
else {
RefPtr<RegisterID> scope = emitResolveScope(nullptr, currentFunctionVariable);
currentValue = emitGetFromScope(newTemporary(), scope.get(), currentFunctionVariable, DoNotThrowIfNotFound);
}
ASSERT(m_varScopeLexicalScopeStackIndex);
ASSERT(*m_varScopeLexicalScopeStackIndex < m_lexicalScopeStack.size());
LexicalScopeStackEntry varScope = m_lexicalScopeStack[*m_varScopeLexicalScopeStackIndex];
SymbolTable* varSymbolTable = varScope.m_symbolTable;
ASSERT(varSymbolTable->scopeType() == SymbolTable::ScopeType::VarScope);
SymbolTableEntry entry = varSymbolTable->get(NoLockingNecessary, functionName.impl());
if (functionName == propertyNames().arguments && entry.isNull()) {
// "arguments" might be put in the parameter scope when we have a non-simple
// parameter list since "arguments" is visible to expressions inside the
// parameter evaluation list.
// e.g:
// function foo(x = arguments) { { function arguments() { } } }
RELEASE_ASSERT(*m_varScopeLexicalScopeStackIndex > 0);
varScope = m_lexicalScopeStack[*m_varScopeLexicalScopeStackIndex - 1];
SymbolTable* parameterSymbolTable = varScope.m_symbolTable;
entry = parameterSymbolTable->get(NoLockingNecessary, functionName.impl());
}
RELEASE_ASSERT(!entry.isNull());
bool isLexicallyScoped = false;
emitPutToScope(varScope.m_scope, variableForLocalEntry(functionName, entry, varScope.m_symbolTableConstantIndex, isLexicallyScoped), currentValue.get(), DoNotThrowIfNotFound, InitializationMode::NotInitialization);
} else {
Variable currentFunctionVariable = variable(functionName);
RefPtr<RegisterID> currentValue;
if (RegisterID* local = currentFunctionVariable.local())
currentValue = local;
else {
RefPtr<RegisterID> scope = emitResolveScope(nullptr, currentFunctionVariable);
currentValue = emitGetFromScope(newTemporary(), scope.get(), currentFunctionVariable, DoNotThrowIfNotFound);
}
RefPtr<RegisterID> scopeId = emitResolveScopeForHoistingFuncDeclInEval(nullptr, functionName);
RefPtr<RegisterID> checkResult = emitIsUndefined(newTemporary(), scopeId.get());
Ref<Label> isNotVarScopeLabel = newLabel();
emitJumpIfTrue(checkResult.get(), isNotVarScopeLabel.get());
// Put to outer scope
emitPutToScope(scopeId.get(), functionName, currentValue.get(), DoNotThrowIfNotFound, InitializationMode::NotInitialization);
emitLabel(isNotVarScopeLabel.get());
}
}
}
RegisterID* BytecodeGenerator::emitResolveScopeForHoistingFuncDeclInEval(RegisterID* dst, const Identifier& property)
{
ASSERT(m_codeType == EvalCode);
dst = finalDestination(dst);
OpResolveScopeForHoistingFuncDeclInEval::emit(this, kill(dst), m_topMostScope, addConstant(property));
return dst;
}
void BytecodeGenerator::popLexicalScope(VariableEnvironmentNode* node)
{
VariableEnvironment& environment = node->lexicalVariables();
popLexicalScopeInternal(environment);
}
void BytecodeGenerator::popLexicalScopeInternal(VariableEnvironment& environment)
{
// NOTE: This function only makes sense for scopes that aren't ScopeRegisterType::Var (only function name scope right now is ScopeRegisterType::Var).
// This doesn't make sense for ScopeRegisterType::Var because we deref RegisterIDs here.
if (!environment.size())
return;
if (shouldEmitDebugHooks())
environment.markAllVariablesAsCaptured();
auto stackEntry = m_lexicalScopeStack.takeLast();
SymbolTable* symbolTable = stackEntry.m_symbolTable;
bool hasCapturedVariables = false;
for (auto& entry : environment) {
if (entry.value.isCaptured()) {
hasCapturedVariables = true;
continue;
}
SymbolTableEntry symbolTableEntry = symbolTable->get(NoLockingNecessary, entry.key.get());
ASSERT(!symbolTableEntry.isNull());
VarOffset offset = symbolTableEntry.varOffset();
ASSERT(offset.isStack());
RegisterID* local = &registerFor(offset.stackOffset());
local->deref();
}
if (hasCapturedVariables) {
RELEASE_ASSERT(stackEntry.m_scope);
emitGetParentScope(scopeRegister(), stackEntry.m_scope);
popLocalControlFlowScope();
stackEntry.m_scope->deref();
}
m_TDZStack.removeLast();
m_cachedVariablesUnderTDZ = { };
}
void BytecodeGenerator::prepareLexicalScopeForNextForLoopIteration(VariableEnvironmentNode* node, RegisterID* loopSymbolTable)
{
VariableEnvironment& environment = node->lexicalVariables();
if (!environment.size())
return;
if (shouldEmitDebugHooks())
environment.markAllVariablesAsCaptured();
if (!environment.hasCapturedVariables())
return;
RELEASE_ASSERT(loopSymbolTable);
// This function needs to do setup for a for loop's activation if any of
// the for loop's lexically declared variables are captured (that is, variables
// declared in the loop header, not the loop body). This function needs to
// make a copy of the current activation and copy the values from the previous
// activation into the new activation because each iteration of a for loop
// gets a new activation.
auto stackEntry = m_lexicalScopeStack.last();
SymbolTable* symbolTable = stackEntry.m_symbolTable;
RegisterID* loopScope = stackEntry.m_scope;
ASSERT(symbolTable->scopeSize());
ASSERT(loopScope);
Vector<std::pair<RegisterID*, Identifier>> activationValuesToCopyOver;
{
activationValuesToCopyOver.reserveInitialCapacity(symbolTable->scopeSize());
for (auto end = symbolTable->end(NoLockingNecessary), ptr = symbolTable->begin(NoLockingNecessary); ptr != end; ++ptr) {
if (!ptr->value.varOffset().isScope())
continue;
RefPtr<UniquedStringImpl> ident = ptr->key;
Identifier identifier = Identifier::fromUid(m_vm, ident.get());
RegisterID* transitionValue = newBlockScopeVariable();
transitionValue->ref();
emitGetFromScope(transitionValue, loopScope, variableForLocalEntry(identifier, ptr->value, loopSymbolTable->index(), true), DoNotThrowIfNotFound);
activationValuesToCopyOver.uncheckedAppend(std::make_pair(transitionValue, identifier));
}
}
// We need this dynamic behavior of the executing code to ensure
// each loop iteration has a new activation object. (It's pretty ugly).
// Also, this new activation needs to be assigned to the same register
// as the previous scope because the loop body is compiled under
// the assumption that the scope's register index is constant even
// though the value in that register will change on each loop iteration.
emitGetParentScope(scopeRegister(), loopScope);
OpCreateLexicalEnvironment::emit(this, loopScope, scopeRegister(), loopSymbolTable, addConstantValue(jsTDZValue()));
move(scopeRegister(), loopScope);
{
for (const auto& pair : activationValuesToCopyOver) {
const Identifier& identifier = pair.second;
SymbolTableEntry entry = symbolTable->get(NoLockingNecessary, identifier.impl());
RELEASE_ASSERT(!entry.isNull());
RegisterID* transitionValue = pair.first;
emitPutToScope(loopScope, variableForLocalEntry(identifier, entry, loopSymbolTable->index(), true), transitionValue, DoNotThrowIfNotFound, InitializationMode::NotInitialization);
transitionValue->deref();
}
}
}
Variable BytecodeGenerator::variable(const Identifier& property, ThisResolutionType thisResolutionType)
{
if (property == propertyNames().thisIdentifier && thisResolutionType == ThisResolutionType::Local)
return Variable(property, VarOffset(thisRegister()->virtualRegister()), thisRegister(), static_cast<unsigned>(PropertyAttribute::ReadOnly), Variable::SpecialVariable, 0, false);
// We can optimize lookups if the lexical variable is found before a "with" or "catch"
// scope because we're guaranteed static resolution. If we have to pass through
// a "with" or "catch" scope we loose this guarantee.
// We can't optimize cases like this:
// {
// let x = ...;
// with (o) {
// doSomethingWith(x);
// }
// }
// Because we can't gaurantee static resolution on x.
// But, in this case, we are guaranteed static resolution:
// {
// let x = ...;
// with (o) {
// let x = ...;
// doSomethingWith(x);
// }
// }
for (unsigned i = m_lexicalScopeStack.size(); i--; ) {
auto& stackEntry = m_lexicalScopeStack[i];
if (stackEntry.m_isWithScope)
return Variable(property);
SymbolTable* symbolTable = stackEntry.m_symbolTable;
SymbolTableEntry symbolTableEntry = symbolTable->get(NoLockingNecessary, property.impl());
if (symbolTableEntry.isNull())
continue;
bool resultIsCallee = false;
if (symbolTable->scopeType() == SymbolTable::ScopeType::FunctionNameScope) {
if (m_usesNonStrictEval) {
// We don't know if an eval has introduced a "var" named the same thing as the function name scope variable name.
// We resort to dynamic lookup to answer this question.
Variable result = Variable(property);
return result;
}
resultIsCallee = true;
}
Variable result = variableForLocalEntry(property, symbolTableEntry, stackEntry.m_symbolTableConstantIndex, symbolTable->scopeType() == SymbolTable::ScopeType::LexicalScope);
if (resultIsCallee)
result.setIsReadOnly();
return result;
}
return Variable(property);
}
Variable BytecodeGenerator::variableForLocalEntry(
const Identifier& property, const SymbolTableEntry& entry, int symbolTableConstantIndex, bool isLexicallyScoped)
{
VarOffset offset = entry.varOffset();
RegisterID* local;
if (offset.isStack())
local = &registerFor(offset.stackOffset());
else
local = nullptr;
return Variable(property, offset, local, entry.getAttributes(), Variable::NormalVariable, symbolTableConstantIndex, isLexicallyScoped);
}
void BytecodeGenerator::createVariable(
const Identifier& property, VarKind varKind, SymbolTable* symbolTable, ExistingVariableMode existingVariableMode)
{
ASSERT(property != propertyNames().thisIdentifier);
SymbolTableEntry entry = symbolTable->get(NoLockingNecessary, property.impl());
if (!entry.isNull()) {
if (existingVariableMode == IgnoreExisting)
return;
// Do some checks to ensure that the variable we're being asked to create is sufficiently
// compatible with the one we have already created.
VarOffset offset = entry.varOffset();
// We can't change our minds about whether it's captured.
if (offset.kind() != varKind) {
dataLog(
"Trying to add variable called ", property, " as ", varKind,
" but it was already added as ", offset, ".\n");
RELEASE_ASSERT_NOT_REACHED();
}
return;
}
VarOffset varOffset;
if (varKind == VarKind::Scope)
varOffset = VarOffset(symbolTable->takeNextScopeOffset(NoLockingNecessary));
else {
ASSERT(varKind == VarKind::Stack);
varOffset = VarOffset(virtualRegisterForLocal(m_calleeLocals.size()));
}
SymbolTableEntry newEntry(varOffset, 0);
symbolTable->add(NoLockingNecessary, property.impl(), newEntry);
if (varKind == VarKind::Stack) {
RegisterID* local = addVar();
RELEASE_ASSERT(local->index() == varOffset.stackOffset().offset());
}
}
RegisterID* BytecodeGenerator::emitOverridesHasInstance(RegisterID* dst, RegisterID* constructor, RegisterID* hasInstanceValue)
{
OpOverridesHasInstance::emit(this, dst, constructor, hasInstanceValue);
return dst;
}
// Indicates the least upper bound of resolve type based on local scope. The bytecode linker
// will start with this ResolveType and compute the least upper bound including intercepting scopes.
ResolveType BytecodeGenerator::resolveType()
{
for (unsigned i = m_lexicalScopeStack.size(); i--; ) {
if (m_lexicalScopeStack[i].m_isWithScope)
return Dynamic;
if (m_usesNonStrictEval && m_lexicalScopeStack[i].m_symbolTable->scopeType() == SymbolTable::ScopeType::FunctionNameScope) {
// We never want to assign to a FunctionNameScope. Returning Dynamic here achieves this goal.
// If we aren't in non-strict eval mode, then NodesCodeGen needs to take care not to emit
// a put_to_scope with the destination being the function name scope variable.
return Dynamic;
}
}
if (m_usesNonStrictEval)
return GlobalPropertyWithVarInjectionChecks;
return GlobalProperty;
}
RegisterID* BytecodeGenerator::emitResolveScope(RegisterID* dst, const Variable& variable)
{
switch (variable.offset().kind()) {
case VarKind::Stack:
return nullptr;
case VarKind::DirectArgument:
return argumentsRegister();
case VarKind::Scope: {
// This always refers to the activation that *we* allocated, and not the current scope that code
// lives in. Note that this will change once we have proper support for block scoping. Once that
// changes, it will be correct for this code to return scopeRegister(). The only reason why we
// don't do that already is that m_lexicalEnvironment is required by ConstDeclNode. ConstDeclNode
// requires weird things because it is a shameful pile of nonsense, but block scoping would make
// that code sensible and obviate the need for us to do bad things.
for (unsigned i = m_lexicalScopeStack.size(); i--; ) {
auto& stackEntry = m_lexicalScopeStack[i];
// We should not resolve a variable to VarKind::Scope if a "with" scope lies in between the current
// scope and the resolved scope.
RELEASE_ASSERT(!stackEntry.m_isWithScope);
if (stackEntry.m_symbolTable->get(NoLockingNecessary, variable.ident().impl()).isNull())
continue;
RegisterID* scope = stackEntry.m_scope;
RELEASE_ASSERT(scope);
return scope;
}
RELEASE_ASSERT_NOT_REACHED();
return nullptr;
}
case VarKind::Invalid:
// Indicates non-local resolution.
dst = tempDestination(dst);
OpResolveScope::emit(this, kill(dst), scopeRegister(), addConstant(variable.ident()), resolveType(), localScopeDepth());
return dst;
}
RELEASE_ASSERT_NOT_REACHED();
return nullptr;
}
RegisterID* BytecodeGenerator::emitGetFromScope(RegisterID* dst, RegisterID* scope, const Variable& variable, ResolveMode resolveMode)
{
switch (variable.offset().kind()) {
case VarKind::Stack:
return move(dst, variable.local());
case VarKind::DirectArgument: {
OpGetFromArguments::emit(this, kill(dst), scope, variable.offset().capturedArgumentsOffset().offset());
return dst;
}
case VarKind::Scope:
case VarKind::Invalid: {
OpGetFromScope::emit(
this,
kill(dst),
scope,
addConstant(variable.ident()),
GetPutInfo(resolveMode, variable.offset().isScope() ? LocalClosureVar : resolveType(), InitializationMode::NotInitialization),
localScopeDepth(),
variable.offset().isScope() ? variable.offset().scopeOffset().offset() : 0);
return dst;
} }
RELEASE_ASSERT_NOT_REACHED();
}
RegisterID* BytecodeGenerator::emitPutToScope(RegisterID* scope, const Variable& variable, RegisterID* value, ResolveMode resolveMode, InitializationMode initializationMode)
{
switch (variable.offset().kind()) {
case VarKind::Stack:
move(variable.local(), value);
return value;
case VarKind::DirectArgument:
OpPutToArguments::emit(this, scope, variable.offset().capturedArgumentsOffset().offset(), value);
return value;
case VarKind::Scope:
case VarKind::Invalid: {
GetPutInfo getPutInfo(0);
SymbolTableOrScopeDepth symbolTableOrScopeDepth;
ScopeOffset offset;
if (variable.offset().isScope()) {
offset = variable.offset().scopeOffset();
getPutInfo = GetPutInfo(resolveMode, LocalClosureVar, initializationMode);
symbolTableOrScopeDepth = SymbolTableOrScopeDepth::symbolTable(VirtualRegister { variable.symbolTableConstantIndex() });
} else {
ASSERT(resolveType() != LocalClosureVar);
getPutInfo = GetPutInfo(resolveMode, resolveType(), initializationMode);
symbolTableOrScopeDepth = SymbolTableOrScopeDepth::scopeDepth(localScopeDepth());
}
OpPutToScope::emit(this, scope, addConstant(variable.ident()), value, getPutInfo, symbolTableOrScopeDepth, !!offset ? offset.offset() : 0);
return value;
} }
RELEASE_ASSERT_NOT_REACHED();
}
RegisterID* BytecodeGenerator::initializeVariable(const Variable& variable, RegisterID* value)
{
RELEASE_ASSERT(variable.offset().kind() != VarKind::Invalid);
RegisterID* scope = emitResolveScope(nullptr, variable);
return emitPutToScope(scope, variable, value, ThrowIfNotFound, InitializationMode::NotInitialization);
}
RegisterID* BytecodeGenerator::emitInstanceOf(RegisterID* dst, RegisterID* value, RegisterID* basePrototype)
{
OpInstanceof::emit(this, dst, value, basePrototype);
return dst;
}
RegisterID* BytecodeGenerator::emitInstanceOfCustom(RegisterID* dst, RegisterID* value, RegisterID* constructor, RegisterID* hasInstanceValue)
{
OpInstanceofCustom::emit(this, dst, value, constructor, hasInstanceValue);
return dst;
}
RegisterID* BytecodeGenerator::emitInByVal(RegisterID* dst, RegisterID* property, RegisterID* base)
{
OpInByVal::emit(this, dst, base, property);
return dst;
}
RegisterID* BytecodeGenerator::emitInById(RegisterID* dst, RegisterID* base, const Identifier& property)
{
OpInById::emit(this, dst, base, addConstant(property));
return dst;
}
RegisterID* BytecodeGenerator::emitTryGetById(RegisterID* dst, RegisterID* base, const Identifier& property)
{
ASSERT_WITH_MESSAGE(!parseIndex(property), "Indexed properties are not supported with tryGetById.");
OpTryGetById::emit(this, kill(dst), base, addConstant(property));
return dst;
}
RegisterID* BytecodeGenerator::emitGetById(RegisterID* dst, RegisterID* base, const Identifier& property)
{
ASSERT_WITH_MESSAGE(!parseIndex(property), "Indexed properties should be handled with get_by_val.");
OpGetById::emit(this, kill(dst), base, addConstant(property));
return dst;
}
RegisterID* BytecodeGenerator::emitGetById(RegisterID* dst, RegisterID* base, RegisterID* thisVal, const Identifier& property)
{
ASSERT_WITH_MESSAGE(!parseIndex(property), "Indexed properties should be handled with get_by_val.");
OpGetByIdWithThis::emit(this, kill(dst), base, thisVal, addConstant(property));
return dst;
}
RegisterID* BytecodeGenerator::emitDirectGetById(RegisterID* dst, RegisterID* base, const Identifier& property)
{
ASSERT_WITH_MESSAGE(!parseIndex(property), "Indexed properties should be handled with get_by_val_direct.");
OpGetByIdDirect::emit(this, kill(dst), base, addConstant(property));
return dst;
}
RegisterID* BytecodeGenerator::emitPutById(RegisterID* base, const Identifier& property, RegisterID* value)
{
ASSERT_WITH_MESSAGE(!parseIndex(property), "Indexed properties should be handled with put_by_val.");
unsigned propertyIndex = addConstant(property);
m_staticPropertyAnalyzer.putById(base, propertyIndex);
OpPutById::emit(this, base, propertyIndex, value, PutByIdNone); // is not direct
return value;
}
RegisterID* BytecodeGenerator::emitPutById(RegisterID* base, RegisterID* thisValue, const Identifier& property, RegisterID* value)
{
ASSERT_WITH_MESSAGE(!parseIndex(property), "Indexed properties should be handled with put_by_val.");
unsigned propertyIndex = addConstant(property);
OpPutByIdWithThis::emit(this, base, thisValue, propertyIndex, value);
return value;
}
RegisterID* BytecodeGenerator::emitDirectPutById(RegisterID* base, const Identifier& property, RegisterID* value, PropertyNode::PutType putType)
{
ASSERT_WITH_MESSAGE(!parseIndex(property), "Indexed properties should be handled with put_by_val(direct).");
unsigned propertyIndex = addConstant(property);
m_staticPropertyAnalyzer.putById(base, propertyIndex);
PutByIdFlags type = (putType == PropertyNode::KnownDirect || property != m_vm.propertyNames->underscoreProto) ? PutByIdIsDirect : PutByIdNone;
OpPutById::emit(this, base, propertyIndex, value, type);
return value;
}
void BytecodeGenerator::emitPutGetterById(RegisterID* base, const Identifier& property, unsigned attributes, RegisterID* getter)
{
unsigned propertyIndex = addConstant(property);
m_staticPropertyAnalyzer.putById(base, propertyIndex);
OpPutGetterById::emit(this, base, propertyIndex, attributes, getter);
}
void BytecodeGenerator::emitPutSetterById(RegisterID* base, const Identifier& property, unsigned attributes, RegisterID* setter)
{
unsigned propertyIndex = addConstant(property);
m_staticPropertyAnalyzer.putById(base, propertyIndex);
OpPutSetterById::emit(this, base, propertyIndex, attributes, setter);
}
void BytecodeGenerator::emitPutGetterSetter(RegisterID* base, const Identifier& property, unsigned attributes, RegisterID* getter, RegisterID* setter)
{
unsigned propertyIndex = addConstant(property);
m_staticPropertyAnalyzer.putById(base, propertyIndex);
OpPutGetterSetterById::emit(this, base, propertyIndex, attributes, getter, setter);
}
void BytecodeGenerator::emitPutGetterByVal(RegisterID* base, RegisterID* property, unsigned attributes, RegisterID* getter)
{
OpPutGetterByVal::emit(this, base, property, attributes, getter);
}
void BytecodeGenerator::emitPutSetterByVal(RegisterID* base, RegisterID* property, unsigned attributes, RegisterID* setter)
{
OpPutSetterByVal::emit(this, base, property, attributes, setter);
}
void BytecodeGenerator::emitPutGeneratorFields(RegisterID* nextFunction)
{
emitPutInternalField(m_generatorRegister, static_cast<unsigned>(JSGenerator::Field::Next), nextFunction);
// We do not store 'this' in arrow function within constructor,
// because it might be not initialized, if super is called later.
if (!(isDerivedConstructorContext() && m_codeBlock->parseMode() == SourceParseMode::AsyncArrowFunctionMode))
emitPutInternalField(m_generatorRegister, static_cast<unsigned>(JSGenerator::Field::This), &m_thisRegister);
}
void BytecodeGenerator::emitPutAsyncGeneratorFields(RegisterID* nextFunction)
{
ASSERT(isAsyncGeneratorWrapperParseMode(parseMode()));
emitPutInternalField(m_generatorRegister, static_cast<unsigned>(JSAsyncGenerator::Field::Next), nextFunction);
emitPutInternalField(m_generatorRegister, static_cast<unsigned>(JSAsyncGenerator::Field::This), &m_thisRegister);
}
RegisterID* BytecodeGenerator::emitDeleteById(RegisterID* dst, RegisterID* base, const Identifier& property)
{
OpDelById::emit(this, dst, base, addConstant(property));
return dst;
}
RegisterID* BytecodeGenerator::emitGetByVal(RegisterID* dst, RegisterID* base, RegisterID* property)
{
for (size_t i = m_forInContextStack.size(); i--; ) {
ForInContext& context = m_forInContextStack[i].get();
if (context.local() != property)
continue;
if (context.isIndexedForInContext()) {
auto& indexedContext = context.asIndexedForInContext();
kill(dst);
if (OpGetByVal::checkWithoutMetadataID<OpcodeSize::Narrow>(this, dst, base, property))
OpGetByVal::emitWithSmallestSizeRequirement<OpcodeSize::Narrow>(this, dst, base, indexedContext.index());
else if (OpGetByVal::checkWithoutMetadataID<OpcodeSize::Wide16>(this, dst, base, property))
OpGetByVal::emitWithSmallestSizeRequirement<OpcodeSize::Wide16>(this, dst, base, indexedContext.index());
else
OpGetByVal::emit<OpcodeSize::Wide32>(this, dst, base, indexedContext.index());
indexedContext.addGetInst(m_lastInstruction.offset(), property->index());
return dst;
}
// We cannot do the above optimization here since OpGetDirectPname => OpGetByVal conversion involves different metadata ID allocation.
StructureForInContext& structureContext = context.asStructureForInContext();
OpGetDirectPname::emit<OpcodeSize::Wide32>(this, kill(dst), base, property, structureContext.index(), structureContext.enumerator());
structureContext.addGetInst(m_lastInstruction.offset(), property->index());
return dst;
}
OpGetByVal::emit(this, kill(dst), base, property);
return dst;
}
RegisterID* BytecodeGenerator::emitGetByVal(RegisterID* dst, RegisterID* base, RegisterID* thisValue, RegisterID* property)
{
OpGetByValWithThis::emit(this, kill(dst), base, thisValue, property);
return dst;
}
RegisterID* BytecodeGenerator::emitPutByVal(RegisterID* base, RegisterID* property, RegisterID* value)
{
OpPutByVal::emit(this, base, property, value);
return value;
}
RegisterID* BytecodeGenerator::emitPutByVal(RegisterID* base, RegisterID* thisValue, RegisterID* property, RegisterID* value)
{
OpPutByValWithThis::emit(this, base, thisValue, property, value);
return value;
}
RegisterID* BytecodeGenerator::emitDirectPutByVal(RegisterID* base, RegisterID* property, RegisterID* value)
{
OpPutByValDirect::emit(this, base, property, value);
return value;
}
RegisterID* BytecodeGenerator::emitDeleteByVal(RegisterID* dst, RegisterID* base, RegisterID* property)
{
OpDelByVal::emit(this, dst, base, property);
return dst;
}
RegisterID* BytecodeGenerator::emitGetInternalField(RegisterID* dst, RegisterID* base, unsigned index)
{
OpGetInternalField::emit(this, dst, base, index);
return dst;
}
RegisterID* BytecodeGenerator::emitPutInternalField(RegisterID* base, unsigned index, RegisterID* value)
{
OpPutInternalField::emit(this, base, index, value);
return value;
}
void BytecodeGenerator::emitSuperSamplerBegin()
{
OpSuperSamplerBegin::emit(this);
}
void BytecodeGenerator::emitSuperSamplerEnd()
{
OpSuperSamplerEnd::emit(this);
}
RegisterID* BytecodeGenerator::emitIdWithProfile(RegisterID* src, SpeculatedType profile)
{
OpIdentityWithProfile::emit(this, src, static_cast<uint32_t>(profile >> 32), static_cast<uint32_t>(profile));
return src;
}
void BytecodeGenerator::emitUnreachable()
{
OpUnreachable::emit(this);
}
RegisterID* BytecodeGenerator::emitGetArgument(RegisterID* dst, int32_t index)
{
OpGetArgument::emit(this, dst, index + 1 /* Including |this| */);
return dst;
}
RegisterID* BytecodeGenerator::emitCreateThis(RegisterID* dst)
{
OpCreateThis::emit(this, dst, dst, 0);
m_staticPropertyAnalyzer.createThis(dst, m_lastInstruction);
return dst;
}
RegisterID* BytecodeGenerator::emitCreatePromise(RegisterID* dst, RegisterID* newTarget, bool isInternalPromise)
{
OpCreatePromise::emit(this, dst, newTarget, isInternalPromise);
return dst;
}
RegisterID* BytecodeGenerator::emitNewPromise(RegisterID* dst, bool isInternalPromise)
{
OpNewPromise::emit(this, dst, isInternalPromise);
return dst;
}
RegisterID* BytecodeGenerator::emitCreateGenerator(RegisterID* dst, RegisterID* newTarget)
{
OpCreateGenerator::emit(this, dst, newTarget);
return dst;
}
RegisterID* BytecodeGenerator::emitNewGenerator(RegisterID* dst)
{
OpNewGenerator::emit(this, dst);
return dst;
}
RegisterID* BytecodeGenerator::emitCreateAsyncGenerator(RegisterID* dst, RegisterID* newTarget)
{
OpCreateAsyncGenerator::emit(this, dst, newTarget);
return dst;
}
RegisterID* BytecodeGenerator::emitCreateArgumentsButterfly(RegisterID* dst)
{
OpCreateArgumentsButterfly::emit(this, dst);
return dst;
}
void BytecodeGenerator::emitTDZCheck(RegisterID* target)
{
OpCheckTdz::emit(this, target);
}
bool BytecodeGenerator::needsTDZCheck(const Variable& variable)
{
for (unsigned i = m_TDZStack.size(); i--;) {
auto iter = m_TDZStack[i].find(variable.ident().impl());
if (iter == m_TDZStack[i].end())
continue;
return iter->value != TDZNecessityLevel::NotNeeded;
}
return false;
}
void BytecodeGenerator::emitTDZCheckIfNecessary(const Variable& variable, RegisterID* target, RegisterID* scope)
{
if (needsTDZCheck(variable)) {
if (target)
emitTDZCheck(target);
else {
RELEASE_ASSERT(!variable.isLocal() && scope);
RefPtr<RegisterID> result = emitGetFromScope(newTemporary(), scope, variable, DoNotThrowIfNotFound);
emitTDZCheck(result.get());
}
}
}
void BytecodeGenerator::liftTDZCheckIfPossible(const Variable& variable)
{
RefPtr<UniquedStringImpl> identifier(variable.ident().impl());
for (unsigned i = m_TDZStack.size(); i--;) {
auto iter = m_TDZStack[i].find(identifier);
if (iter != m_TDZStack[i].end()) {
if (iter->value == TDZNecessityLevel::Optimize) {
m_cachedVariablesUnderTDZ = { };
iter->value = TDZNecessityLevel::NotNeeded;
}
break;
}
}
}
void BytecodeGenerator::pushTDZVariables(const VariableEnvironment& environment, TDZCheckOptimization optimization, TDZRequirement requirement)
{
if (!environment.size())
return;
TDZNecessityLevel level;
if (requirement == TDZRequirement::UnderTDZ) {
if (optimization == TDZCheckOptimization::Optimize)
level = TDZNecessityLevel::Optimize;
else
level = TDZNecessityLevel::DoNotOptimize;
} else
level = TDZNecessityLevel::NotNeeded;
TDZMap map;
for (const auto& entry : environment)
map.add(entry.key, entry.value.isFunction() ? TDZNecessityLevel::NotNeeded : level);
m_TDZStack.append(WTFMove(map));
m_cachedVariablesUnderTDZ = { };
}
Optional<CompactVariableMap::Handle> BytecodeGenerator::getVariablesUnderTDZ()
{
if (m_cachedVariablesUnderTDZ) {
if (!m_hasCachedVariablesUnderTDZ) {
ASSERT(m_cachedVariablesUnderTDZ.environment().toVariableEnvironment().isEmpty());
return WTF::nullopt;
}
return m_cachedVariablesUnderTDZ;
}
// We keep track of variablesThatDontNeedTDZ in this algorithm to prevent
// reporting that "x" is under TDZ if this function is called at "...".
//
// {
// {
// let x;
// ...
// }
// let x;
// }
SmallPtrSet<UniquedStringImpl*, 16> variablesThatDontNeedTDZ;
VariableEnvironment environment;
for (unsigned i = m_TDZStack.size(); i--; ) {
auto& map = m_TDZStack[i];
for (auto& entry : map) {
if (entry.value != TDZNecessityLevel::NotNeeded) {
if (!variablesThatDontNeedTDZ.contains(entry.key.get()))
environment.add(entry.key.get());
} else
variablesThatDontNeedTDZ.add(entry.key.get());
}
}
m_cachedVariablesUnderTDZ = m_vm.m_compactVariableMap->get(environment);
m_hasCachedVariablesUnderTDZ = !environment.isEmpty();
if (!m_hasCachedVariablesUnderTDZ)
return WTF::nullopt;
return m_cachedVariablesUnderTDZ;
}
void BytecodeGenerator::preserveTDZStack(BytecodeGenerator::PreservedTDZStack& preservedStack)
{
preservedStack.m_preservedTDZStack = m_TDZStack;
}
void BytecodeGenerator::restoreTDZStack(const BytecodeGenerator::PreservedTDZStack& preservedStack)
{
m_TDZStack = preservedStack.m_preservedTDZStack;
m_cachedVariablesUnderTDZ = { };
}
RegisterID* BytecodeGenerator::emitNewObject(RegisterID* dst)
{
OpNewObject::emit(this, dst, 0);
m_staticPropertyAnalyzer.newObject(dst, m_lastInstruction);
return dst;
}
JSValue BytecodeGenerator::addBigIntConstant(const Identifier& identifier, uint8_t radix, bool sign)
{
return m_bigIntMap.ensure(BigIntMapEntry(identifier.impl(), radix, sign), [&] {
auto scope = DECLARE_CATCH_SCOPE(vm());
auto parseIntSign = sign ? JSBigInt::ParseIntSign::Signed : JSBigInt::ParseIntSign::Unsigned;
JSBigInt* bigIntInMap = JSBigInt::parseInt(nullptr, vm(), identifier.string(), radix, JSBigInt::ErrorParseMode::ThrowExceptions, parseIntSign);
// FIXME: [ESNext] Enables a way to throw an error on ByteCodeGenerator step
// https://bugs.webkit.org/show_bug.cgi?id=180139
scope.assertNoException();
RELEASE_ASSERT(bigIntInMap);
addConstantValue(bigIntInMap);
return bigIntInMap;
}).iterator->value;
}
JSString* BytecodeGenerator::addStringConstant(const Identifier& identifier)
{
JSString*& stringInMap = m_stringMap.add(identifier.impl(), nullptr).iterator->value;
if (!stringInMap) {
stringInMap = jsString(vm(), identifier.string());
addConstantValue(stringInMap);
}
return stringInMap;
}
RegisterID* BytecodeGenerator::addTemplateObjectConstant(Ref<TemplateObjectDescriptor>&& descriptor, int endOffset)
{
auto result = m_templateObjectDescriptorSet.add(WTFMove(descriptor));
JSTemplateObjectDescriptor* descriptorValue = m_templateDescriptorMap.ensure(endOffset, [&] {
return JSTemplateObjectDescriptor::create(vm(), result.iterator->copyRef(), endOffset);
}).iterator->value;
int index = addConstantIndex();
m_codeBlock->addConstant(descriptorValue);
return &m_constantPoolRegisters[index];
}
RegisterID* BytecodeGenerator::emitNewArrayBuffer(RegisterID* dst, JSImmutableButterfly* array, IndexingType recommendedIndexingType)
{
OpNewArrayBuffer::emit(this, dst, addConstantValue(array), recommendedIndexingType);
return dst;
}
RegisterID* BytecodeGenerator::emitNewArray(RegisterID* dst, ElementNode* elements, unsigned length, IndexingType recommendedIndexingType)
{
Vector<RefPtr<RegisterID>, 16, UnsafeVectorOverflow> argv;
for (ElementNode* n = elements; n; n = n->next()) {
if (!length)
break;
length--;
ASSERT(!n->value()->isSpreadExpression());
argv.append(newTemporary());
// op_new_array requires the initial values to be a sequential range of registers
ASSERT(argv.size() == 1 || argv[argv.size() - 1]->index() == argv[argv.size() - 2]->index() - 1);
emitNode(argv.last().get(), n->value());
}
ASSERT(!length);
OpNewArray::emit(this, dst, argv.size() ? argv[0].get() : VirtualRegister { 0 }, argv.size(), recommendedIndexingType);
return dst;
}
RegisterID* BytecodeGenerator::emitNewArrayWithSpread(RegisterID* dst, ElementNode* elements)
{
BitVector bitVector;
Vector<RefPtr<RegisterID>, 16> argv;
for (ElementNode* node = elements; node; node = node->next()) {
bitVector.set(argv.size(), node->value()->isSpreadExpression());
argv.append(newTemporary());
// op_new_array_with_spread requires the initial values to be a sequential range of registers.
RELEASE_ASSERT(argv.size() == 1 || argv[argv.size() - 1]->index() == argv[argv.size() - 2]->index() - 1);
}
RELEASE_ASSERT(argv.size());
{
unsigned i = 0;
for (ElementNode* node = elements; node; node = node->next()) {
if (node->value()->isSpreadExpression()) {
ExpressionNode* expression = static_cast<SpreadExpressionNode*>(node->value())->expression();
RefPtr<RegisterID> tmp = newTemporary();
emitNode(tmp.get(), expression);
OpSpread::emit(this, argv[i].get(), tmp.get());
} else {
ExpressionNode* expression = node->value();
emitNode(argv[i].get(), expression);
}
i++;
}
}
unsigned bitVectorIndex = m_codeBlock->addBitVector(WTFMove(bitVector));
OpNewArrayWithSpread::emit(this, dst, argv[0].get(), argv.size(), bitVectorIndex);
return dst;
}
RegisterID* BytecodeGenerator::emitNewArrayWithSize(RegisterID* dst, RegisterID* length)
{
OpNewArrayWithSize::emit(this, dst, length);
return dst;
}
RegisterID* BytecodeGenerator::emitNewRegExp(RegisterID* dst, RegExp* regExp)
{
OpNewRegexp::emit(this, dst, addConstantValue(regExp));
return dst;
}
void BytecodeGenerator::emitNewFunctionExpressionCommon(RegisterID* dst, FunctionMetadataNode* function)
{
unsigned index = m_codeBlock->addFunctionExpr(makeFunction(function));
switch (function->parseMode()) {
case SourceParseMode::GeneratorWrapperFunctionMode:
case SourceParseMode::GeneratorWrapperMethodMode:
OpNewGeneratorFuncExp::emit(this, dst, scopeRegister(), index);
break;
case SourceParseMode::AsyncFunctionMode:
case SourceParseMode::AsyncMethodMode:
case SourceParseMode::AsyncArrowFunctionMode:
OpNewAsyncFuncExp::emit(this, dst, scopeRegister(), index);
break;
case SourceParseMode::AsyncGeneratorWrapperFunctionMode:
case SourceParseMode::AsyncGeneratorWrapperMethodMode:
OpNewAsyncGeneratorFuncExp::emit(this, dst, scopeRegister(), index);
break;
default:
OpNewFuncExp::emit(this, dst, scopeRegister(), index);
break;
}
}
RegisterID* BytecodeGenerator::emitNewFunctionExpression(RegisterID* dst, FuncExprNode* func)
{
emitNewFunctionExpressionCommon(dst, func->metadata());
return dst;
}
RegisterID* BytecodeGenerator::emitNewArrowFunctionExpression(RegisterID* dst, ArrowFuncExprNode* func)
{
ASSERT(SourceParseModeSet(SourceParseMode::ArrowFunctionMode, SourceParseMode::AsyncArrowFunctionMode).contains(func->metadata()->parseMode()));
emitNewFunctionExpressionCommon(dst, func->metadata());
return dst;
}
RegisterID* BytecodeGenerator::emitNewMethodDefinition(RegisterID* dst, MethodDefinitionNode* func)
{
ASSERT(isMethodParseMode(func->metadata()->parseMode()));
emitNewFunctionExpressionCommon(dst, func->metadata());
return dst;
}
RegisterID* BytecodeGenerator::emitNewDefaultConstructor(RegisterID* dst, ConstructorKind constructorKind, const Identifier& name,
const Identifier& ecmaName, const SourceCode& classSource)
{
UnlinkedFunctionExecutable* executable = m_vm.builtinExecutables()->createDefaultConstructor(constructorKind, name);
executable->setInvalidTypeProfilingOffsets();
executable->setEcmaName(ecmaName);
executable->setClassSource(classSource);
unsigned index = m_codeBlock->addFunctionExpr(executable);
OpNewFuncExp::emit(this, dst, scopeRegister(), index);
return dst;
}
RegisterID* BytecodeGenerator::emitNewFunction(RegisterID* dst, FunctionMetadataNode* function)
{
unsigned index = m_codeBlock->addFunctionDecl(makeFunction(function));
if (isGeneratorWrapperParseMode(function->parseMode()))
OpNewGeneratorFunc::emit(this, dst, scopeRegister(), index);
else if (function->parseMode() == SourceParseMode::AsyncFunctionMode)
OpNewAsyncFunc::emit(this, dst, scopeRegister(), index);
else if (isAsyncGeneratorWrapperParseMode(function->parseMode()))
OpNewAsyncGeneratorFunc::emit(this, dst, scopeRegister(), index);
else
OpNewFunc::emit(this, dst, scopeRegister(), index);
return dst;
}
void BytecodeGenerator::emitSetFunctionNameIfNeeded(ExpressionNode* valueNode, RegisterID* value, RegisterID* name)
{
if (valueNode->isBaseFuncExprNode()) {
FunctionMetadataNode* metadata = static_cast<BaseFuncExprNode*>(valueNode)->metadata();
if (!metadata->ecmaName().isNull())
return;
} else if (valueNode->isClassExprNode()) {
ClassExprNode* classExprNode = static_cast<ClassExprNode*>(valueNode);
if (!classExprNode->ecmaName().isNull())
return;
if (classExprNode->hasStaticProperty(m_vm.propertyNames->name))
return;
} else
return;
// FIXME: We should use an op_call to an internal function here instead.
// https://bugs.webkit.org/show_bug.cgi?id=155547
OpSetFunctionName::emit(this, value, name);
}
RegisterID* BytecodeGenerator::emitCall(RegisterID* dst, RegisterID* func, ExpectedFunction expectedFunction, CallArguments& callArguments, const JSTextPosition& divot, const JSTextPosition& divotStart, const JSTextPosition& divotEnd, DebuggableCall debuggableCall)
{
return emitCall<OpCall>(dst, func, expectedFunction, callArguments, divot, divotStart, divotEnd, debuggableCall);
}
RegisterID* BytecodeGenerator::emitCallInTailPosition(RegisterID* dst, RegisterID* func, ExpectedFunction expectedFunction, CallArguments& callArguments, const JSTextPosition& divot, const JSTextPosition& divotStart, const JSTextPosition& divotEnd, DebuggableCall debuggableCall)
{
if (m_inTailPosition) {
m_codeBlock->setHasTailCalls();
return emitCall<OpTailCall>(dst, func, expectedFunction, callArguments, divot, divotStart, divotEnd, debuggableCall);
}
return emitCall<OpCall>(dst, func, expectedFunction, callArguments, divot, divotStart, divotEnd, debuggableCall);
}
RegisterID* BytecodeGenerator::emitCallEval(RegisterID* dst, RegisterID* func, CallArguments& callArguments, const JSTextPosition& divot, const JSTextPosition& divotStart, const JSTextPosition& divotEnd, DebuggableCall debuggableCall)
{
return emitCall<OpCallEval>(dst, func, NoExpectedFunction, callArguments, divot, divotStart, divotEnd, debuggableCall);
}
ExpectedFunction BytecodeGenerator::expectedFunctionForIdentifier(const Identifier& identifier)
{
if (identifier == propertyNames().Object || identifier == propertyNames().builtinNames().ObjectPrivateName())
return ExpectObjectConstructor;
if (identifier == propertyNames().Array || identifier == propertyNames().builtinNames().ArrayPrivateName())
return ExpectArrayConstructor;
return NoExpectedFunction;
}
ExpectedFunction BytecodeGenerator::emitExpectedFunctionSnippet(RegisterID* dst, RegisterID* func, ExpectedFunction expectedFunction, CallArguments& callArguments, Label& done)
{
Ref<Label> realCall = newLabel();
switch (expectedFunction) {
case ExpectObjectConstructor: {
// If the number of arguments is non-zero, then we can't do anything interesting.
if (callArguments.argumentCountIncludingThis() >= 2)
return NoExpectedFunction;
OpJneqPtr::emit(this, func, moveLinkTimeConstant(nullptr, LinkTimeConstant::Object), realCall->bind(this));
if (dst != ignoredResult())
emitNewObject(dst);
break;
}
case ExpectArrayConstructor: {
// If you're doing anything other than "new Array()" or "new Array(foo)" then we
// don't do inline it, for now. The only reason is that call arguments are in
// the opposite order of what op_new_array expects, so we'd either need to change
// how op_new_array works or we'd need an op_new_array_reverse. Neither of these
// things sounds like it's worth it.
if (callArguments.argumentCountIncludingThis() > 2)
return NoExpectedFunction;
OpJneqPtr::emit(this, func, moveLinkTimeConstant(nullptr, LinkTimeConstant::Array), realCall->bind(this));
if (dst != ignoredResult()) {
if (callArguments.argumentCountIncludingThis() == 2)
emitNewArrayWithSize(dst, callArguments.argumentRegister(0));
else {
ASSERT(callArguments.argumentCountIncludingThis() == 1);
OpNewArray::emit(this, dst, VirtualRegister { 0 }, 0, ArrayWithUndecided);
}
}
break;
}
default:
ASSERT(expectedFunction == NoExpectedFunction);
return NoExpectedFunction;
}
OpJmp::emit(this, done.bind(this));
emitLabel(realCall.get());
return expectedFunction;
}
template<typename CallOp>
RegisterID* BytecodeGenerator::emitCall(RegisterID* dst, RegisterID* func, ExpectedFunction expectedFunction, CallArguments& callArguments, const JSTextPosition& divot, const JSTextPosition& divotStart, const JSTextPosition& divotEnd, DebuggableCall debuggableCall)
{
constexpr auto opcodeID = CallOp::opcodeID;
ASSERT(opcodeID == op_call || opcodeID == op_call_eval || opcodeID == op_tail_call);
ASSERT(func->refCount());
// Generate code for arguments.
unsigned argument = 0;
if (callArguments.argumentsNode()) {
ArgumentListNode* n = callArguments.argumentsNode()->m_listNode;
if (n && n->m_expr->isSpreadExpression()) {
RELEASE_ASSERT(!n->m_next);
auto expression = static_cast<SpreadExpressionNode*>(n->m_expr)->expression();
if (expression->isArrayLiteral()) {
auto* elements = static_cast<ArrayNode*>(expression)->elements();
if (elements && !elements->next() && elements->value()->isSpreadExpression()) {
ExpressionNode* expression = static_cast<SpreadExpressionNode*>(elements->value())->expression();
RefPtr<RegisterID> argumentRegister = emitNode(callArguments.argumentRegister(0), expression);
OpSpread::emit(this, argumentRegister.get(), argumentRegister.get());
return emitCallVarargs<typename VarArgsOp<CallOp>::type>(dst, func, callArguments.thisRegister(), argumentRegister.get(), newTemporary(), 0, divot, divotStart, divotEnd, debuggableCall);
}
}
RefPtr<RegisterID> argumentRegister;
argumentRegister = expression->emitBytecode(*this, callArguments.argumentRegister(0));
RefPtr<RegisterID> thisRegister = move(newTemporary(), callArguments.thisRegister());
return emitCallVarargs<typename VarArgsOp<CallOp>::type>(dst, func, callArguments.thisRegister(), argumentRegister.get(), newTemporary(), 0, divot, divotStart, divotEnd, debuggableCall);
}
for (; n; n = n->m_next)
emitNode(callArguments.argumentRegister(argument++), n);
}
// Reserve space for call frame.
Vector<RefPtr<RegisterID>, CallFrame::headerSizeInRegisters, UnsafeVectorOverflow> callFrame;
for (int i = 0; i < CallFrame::headerSizeInRegisters; ++i)
callFrame.append(newTemporary());
if (shouldEmitDebugHooks() && debuggableCall == DebuggableCall::Yes)
emitDebugHook(WillExecuteExpression, divotStart);
emitExpressionInfo(divot, divotStart, divotEnd);
Ref<Label> done = newLabel();
expectedFunction = emitExpectedFunctionSnippet(dst, func, expectedFunction, callArguments, done.get());
if (opcodeID == op_tail_call)
emitLogShadowChickenTailIfNecessary();
// Emit call.
ASSERT(dst);
ASSERT(dst != ignoredResult());
CallOp::emit(this, dst, func, callArguments.argumentCountIncludingThis(), callArguments.stackOffset());
if (expectedFunction != NoExpectedFunction)
emitLabel(done.get());
return dst;
}
RegisterID* BytecodeGenerator::emitCallVarargs(RegisterID* dst, RegisterID* func, RegisterID* thisRegister, RegisterID* arguments, RegisterID* firstFreeRegister, int32_t firstVarArgOffset, const JSTextPosition& divot, const JSTextPosition& divotStart, const JSTextPosition& divotEnd, DebuggableCall debuggableCall)
{
return emitCallVarargs<OpCallVarargs>(dst, func, thisRegister, arguments, firstFreeRegister, firstVarArgOffset, divot, divotStart, divotEnd, debuggableCall);
}
RegisterID* BytecodeGenerator::emitCallVarargsInTailPosition(RegisterID* dst, RegisterID* func, RegisterID* thisRegister, RegisterID* arguments, RegisterID* firstFreeRegister, int32_t firstVarArgOffset, const JSTextPosition& divot, const JSTextPosition& divotStart, const JSTextPosition& divotEnd, DebuggableCall debuggableCall)
{
if (m_inTailPosition)
return emitCallVarargs<OpTailCallVarargs>(dst, func, thisRegister, arguments, firstFreeRegister, firstVarArgOffset, divot, divotStart, divotEnd, debuggableCall);
return emitCallVarargs<OpCallVarargs>(dst, func, thisRegister, arguments, firstFreeRegister, firstVarArgOffset, divot, divotStart, divotEnd, debuggableCall);
}
RegisterID* BytecodeGenerator::emitConstructVarargs(RegisterID* dst, RegisterID* func, RegisterID* thisRegister, RegisterID* arguments, RegisterID* firstFreeRegister, int32_t firstVarArgOffset, const JSTextPosition& divot, const JSTextPosition& divotStart, const JSTextPosition& divotEnd, DebuggableCall debuggableCall)
{
return emitCallVarargs<OpConstructVarargs>(dst, func, thisRegister, arguments, firstFreeRegister, firstVarArgOffset, divot, divotStart, divotEnd, debuggableCall);
}
RegisterID* BytecodeGenerator::emitCallForwardArgumentsInTailPosition(RegisterID* dst, RegisterID* func, RegisterID* thisRegister, RegisterID* firstFreeRegister, int32_t firstVarArgOffset, const JSTextPosition& divot, const JSTextPosition& divotStart, const JSTextPosition& divotEnd, DebuggableCall debuggableCall)
{
// We must emit a tail call here because we did not allocate an arguments object thus we would otherwise have no way to correctly make this call.
ASSERT(m_inTailPosition || !Options::useTailCalls());
return emitCallVarargs<OpTailCallForwardArguments>(dst, func, thisRegister, nullptr, firstFreeRegister, firstVarArgOffset, divot, divotStart, divotEnd, debuggableCall);
}
template<typename VarargsOp>
RegisterID* BytecodeGenerator::emitCallVarargs(RegisterID* dst, RegisterID* func, RegisterID* thisRegister, RegisterID* arguments, RegisterID* firstFreeRegister, int32_t firstVarArgOffset, const JSTextPosition& divot, const JSTextPosition& divotStart, const JSTextPosition& divotEnd, DebuggableCall debuggableCall)
{
if (shouldEmitDebugHooks() && debuggableCall == DebuggableCall::Yes)
emitDebugHook(WillExecuteExpression, divotStart);
emitExpressionInfo(divot, divotStart, divotEnd);
if (VarargsOp::opcodeID == op_tail_call_varargs)
emitLogShadowChickenTailIfNecessary();
// Emit call.
ASSERT(dst != ignoredResult());
VarargsOp::emit(this, dst, func, thisRegister, arguments ? arguments : VirtualRegister(0), firstFreeRegister, firstVarArgOffset);
if (VarargsOp::opcodeID != op_tail_call_forward_arguments)
ASSERT(m_codeBlock->hasCheckpoints());
return dst;
}
void BytecodeGenerator::emitLogShadowChickenPrologueIfNecessary()
{
if (!shouldEmitDebugHooks() && !Options::alwaysUseShadowChicken())
return;
OpLogShadowChickenPrologue::emit(this, scopeRegister());
}
void BytecodeGenerator::emitLogShadowChickenTailIfNecessary()
{
if (!shouldEmitDebugHooks() && !Options::alwaysUseShadowChicken())
return;
OpLogShadowChickenTail::emit(this, thisRegister(), scopeRegister());
}
void BytecodeGenerator::emitCallDefineProperty(RegisterID* newObj, RegisterID* propertyNameRegister,
RegisterID* valueRegister, RegisterID* getterRegister, RegisterID* setterRegister, unsigned options, const JSTextPosition& position)
{
DefinePropertyAttributes attributes;
if (options & PropertyConfigurable)
attributes.setConfigurable(true);
if (options & PropertyWritable)
attributes.setWritable(true);
else if (valueRegister)
attributes.setWritable(false);
if (options & PropertyEnumerable)
attributes.setEnumerable(true);
if (valueRegister)
attributes.setValue();
if (getterRegister)
attributes.setGet();
if (setterRegister)
attributes.setSet();
ASSERT(!valueRegister || (!getterRegister && !setterRegister));
emitExpressionInfo(position, position, position);
if (attributes.hasGet() || attributes.hasSet()) {
RefPtr<RegisterID> throwTypeErrorFunction;
if (!attributes.hasGet() || !attributes.hasSet())
throwTypeErrorFunction = moveLinkTimeConstant(nullptr, LinkTimeConstant::throwTypeErrorFunction);
RefPtr<RegisterID> getter;
if (attributes.hasGet())
getter = getterRegister;
else
getter = throwTypeErrorFunction;
RefPtr<RegisterID> setter;
if (attributes.hasSet())
setter = setterRegister;
else
setter = throwTypeErrorFunction;
OpDefineAccessorProperty::emit(this, newObj, propertyNameRegister, getter.get(), setter.get(), emitLoad(nullptr, jsNumber(attributes.rawRepresentation())));
} else {
OpDefineDataProperty::emit(this, newObj, propertyNameRegister, valueRegister, emitLoad(nullptr, jsNumber(attributes.rawRepresentation())));
}
}
RegisterID* BytecodeGenerator::emitReturn(RegisterID* src, ReturnFrom from)
{
// Normal functions and naked constructors do not handle `return` specially.
if (isConstructor() && constructorKind() != ConstructorKind::Naked) {
bool isDerived = constructorKind() == ConstructorKind::Extends;
bool srcIsThis = src->index() == m_thisRegister.index();
if (isDerived && (srcIsThis || from == ReturnFrom::Finally))
emitTDZCheck(src);
if (!srcIsThis || from == ReturnFrom::Finally) {
Ref<Label> isObjectLabel = newLabel();
emitJumpIfTrue(emitIsObject(newTemporary(), src), isObjectLabel.get());
if (isDerived) {
Ref<Label> isUndefinedLabel = newLabel();
emitJumpIfTrue(emitIsUndefined(newTemporary(), src), isUndefinedLabel.get());
emitThrowTypeError("Cannot return a non-object type in the constructor of a derived class.");
emitLabel(isUndefinedLabel.get());
emitTDZCheck(&m_thisRegister);
}
OpRet::emit(this, &m_thisRegister);
emitLabel(isObjectLabel.get());
}
}
OpRet::emit(this, src);
return src;
}
RegisterID* BytecodeGenerator::emitEnd(RegisterID* src)
{
OpEnd::emit(this, src);
return src;
}
RegisterID* BytecodeGenerator::emitConstruct(RegisterID* dst, RegisterID* func, RegisterID* lazyThis, ExpectedFunction expectedFunction, CallArguments& callArguments, const JSTextPosition& divot, const JSTextPosition& divotStart, const JSTextPosition& divotEnd)
{
ASSERT(func->refCount());
// Generate code for arguments.
unsigned argument = 0;
if (ArgumentsNode* argumentsNode = callArguments.argumentsNode()) {
ArgumentListNode* n = callArguments.argumentsNode()->m_listNode;
if (n && n->m_expr->isSpreadExpression()) {
RELEASE_ASSERT(!n->m_next);
auto expression = static_cast<SpreadExpressionNode*>(n->m_expr)->expression();
if (expression->isArrayLiteral()) {
auto* elements = static_cast<ArrayNode*>(expression)->elements();
if (elements && !elements->next() && elements->value()->isSpreadExpression()) {
ExpressionNode* expression = static_cast<SpreadExpressionNode*>(elements->value())->expression();
RefPtr<RegisterID> argumentRegister = emitNode(callArguments.argumentRegister(0), expression);
OpSpread::emit(this, argumentRegister.get(), argumentRegister.get());
move(callArguments.thisRegister(), lazyThis);
RefPtr<RegisterID> thisRegister = move(newTemporary(), callArguments.thisRegister());
return emitConstructVarargs(dst, func, callArguments.thisRegister(), argumentRegister.get(), newTemporary(), 0, divot, divotStart, divotEnd, DebuggableCall::No);
}
}
RefPtr<RegisterID> argumentRegister;
argumentRegister = expression->emitBytecode(*this, callArguments.argumentRegister(0));
move(callArguments.thisRegister(), lazyThis);
return emitConstructVarargs(dst, func, callArguments.thisRegister(), argumentRegister.get(), newTemporary(), 0, divot, divotStart, divotEnd, DebuggableCall::No);
}
for (ArgumentListNode* n = argumentsNode->m_listNode; n; n = n->m_next)
emitNode(callArguments.argumentRegister(argument++), n);
}
move(callArguments.thisRegister(), lazyThis);
// Reserve space for call frame.
Vector<RefPtr<RegisterID>, CallFrame::headerSizeInRegisters, UnsafeVectorOverflow> callFrame;
for (int i = 0; i < CallFrame::headerSizeInRegisters; ++i)
callFrame.append(newTemporary());
emitExpressionInfo(divot, divotStart, divotEnd);
Ref<Label> done = newLabel();
expectedFunction = emitExpectedFunctionSnippet(dst, func, expectedFunction, callArguments, done.get());
OpConstruct::emit(this, dst, func, callArguments.argumentCountIncludingThis(), callArguments.stackOffset());
if (expectedFunction != NoExpectedFunction)
emitLabel(done.get());
return dst;
}
RegisterID* BytecodeGenerator::emitStrcat(RegisterID* dst, RegisterID* src, int count)
{
OpStrcat::emit(this, dst, src, count);
return dst;
}
void BytecodeGenerator::emitToPrimitive(RegisterID* dst, RegisterID* src)
{
OpToPrimitive::emit(this, dst, src);
}
void BytecodeGenerator::emitGetScope()
{
OpGetScope::emit(this, scopeRegister());
}
RegisterID* BytecodeGenerator::emitPushWithScope(RegisterID* objectScope)
{
pushLocalControlFlowScope();
RegisterID* newScope = newBlockScopeVariable();
newScope->ref();
OpPushWithScope::emit(this, newScope, scopeRegister(), objectScope);
move(scopeRegister(), newScope);
m_lexicalScopeStack.append({ nullptr, newScope, true, 0 });
return newScope;
}
RegisterID* BytecodeGenerator::emitGetParentScope(RegisterID* dst, RegisterID* scope)
{
OpGetParentScope::emit(this, dst, scope);
return dst;
}
void BytecodeGenerator::emitPopWithScope()
{
emitGetParentScope(scopeRegister(), scopeRegister());
popLocalControlFlowScope();
auto stackEntry = m_lexicalScopeStack.takeLast();
stackEntry.m_scope->deref();
RELEASE_ASSERT(stackEntry.m_isWithScope);
}
void BytecodeGenerator::emitDebugHook(DebugHookType debugHookType, const JSTextPosition& divot)
{
if (!shouldEmitDebugHooks())
return;
emitExpressionInfo(divot, divot, divot);
OpDebug::emit(this, debugHookType, false);
}
void BytecodeGenerator::emitDebugHook(DebugHookType debugHookType, unsigned line, unsigned charOffset, unsigned lineStart)
{
emitDebugHook(debugHookType, JSTextPosition(line, charOffset, lineStart));
}
void BytecodeGenerator::emitDebugHook(StatementNode* statement)
{
// DebuggerStatementNode will output its own special debug hook.
if (statement->isDebuggerStatement())
return;
emitDebugHook(WillExecuteStatement, statement->position());
}
void BytecodeGenerator::emitDebugHook(ExpressionNode* expr)
{
emitDebugHook(WillExecuteStatement, expr->position());
}
void BytecodeGenerator::emitWillLeaveCallFrameDebugHook()
{
RELEASE_ASSERT(m_scopeNode->isFunctionNode());
emitDebugHook(WillLeaveCallFrame, m_scopeNode->lastLine(), m_scopeNode->startOffset(), m_scopeNode->lineStartOffset());
}
void BytecodeGenerator::pushFinallyControlFlowScope(FinallyContext& finallyContext)
{
ControlFlowScope scope(ControlFlowScope::Finally, currentLexicalScopeIndex(), &finallyContext);
m_controlFlowScopeStack.append(WTFMove(scope));
m_finallyDepth++;
m_currentFinallyContext = &finallyContext;
}
void BytecodeGenerator::popFinallyControlFlowScope()
{
ASSERT(m_controlFlowScopeStack.size());
ASSERT(m_controlFlowScopeStack.last().isFinallyScope());
ASSERT(m_finallyDepth > 0);
ASSERT(m_currentFinallyContext);
m_currentFinallyContext = m_currentFinallyContext->outerContext();
m_finallyDepth--;
m_controlFlowScopeStack.removeLast();
}
LabelScope* BytecodeGenerator::breakTarget(const Identifier& name)
{
shrinkToFit(m_labelScopes);
if (!m_labelScopes.size())
return nullptr;
// We special-case the following, which is a syntax error in Firefox:
// label:
// break;
if (name.isEmpty()) {
for (int i = m_labelScopes.size() - 1; i >= 0; --i) {
LabelScope& scope = m_labelScopes[i];
if (scope.type() != LabelScope::NamedLabel)
return &scope;
}
return nullptr;
}
for (int i = m_labelScopes.size() - 1; i >= 0; --i) {
LabelScope& scope = m_labelScopes[i];
if (scope.name() && *scope.name() == name)
return &scope;
}
return nullptr;
}
LabelScope* BytecodeGenerator::continueTarget(const Identifier& name)
{
shrinkToFit(m_labelScopes);
if (!m_labelScopes.size())
return nullptr;
if (name.isEmpty()) {
for (int i = m_labelScopes.size() - 1; i >= 0; --i) {
LabelScope& scope = m_labelScopes[i];
if (scope.type() == LabelScope::Loop) {
ASSERT(scope.continueTarget());
return &scope;
}
}
return nullptr;
}
// Continue to the loop nested nearest to the label scope that matches
// 'name'.
LabelScope* result = nullptr;
for (int i = m_labelScopes.size() - 1; i >= 0; --i) {
LabelScope& scope = m_labelScopes[i];
if (scope.type() == LabelScope::Loop) {
ASSERT(scope.continueTarget());
result = &scope;
}
if (scope.name() && *scope.name() == name)
return result; // may be null.
}
return nullptr;
}
void BytecodeGenerator::allocateAndEmitScope()
{
m_scopeRegister = addVar();
m_scopeRegister->ref();
m_codeBlock->setScopeRegister(scopeRegister()->virtualRegister());
emitGetScope();
m_topMostScope = addVar();
move(m_topMostScope, scopeRegister());
}
TryData* BytecodeGenerator::pushTry(Label& start, Label& handlerLabel, HandlerType handlerType)
{
m_tryData.append(TryData { handlerLabel, handlerType });
TryData* result = &m_tryData.last();
m_tryContextStack.append(TryContext {
start,
result
});
return result;
}
void BytecodeGenerator::popTry(TryData* tryData, Label& end)
{
m_usesExceptions = true;
ASSERT_UNUSED(tryData, m_tryContextStack.last().tryData == tryData);
m_tryRanges.append(TryRange {
m_tryContextStack.last().start.copyRef(),
end,
m_tryContextStack.last().tryData
});
m_tryContextStack.removeLast();
}
void BytecodeGenerator::emitOutOfLineCatchHandler(RegisterID* thrownValueRegister, RegisterID* completionTypeRegister, TryData* data)
{
RegisterID* unused = newTemporary();
emitOutOfLineExceptionHandler(unused, thrownValueRegister, completionTypeRegister, data);
}
void BytecodeGenerator::emitOutOfLineFinallyHandler(RegisterID* exceptionRegister, RegisterID* completionTypeRegister, TryData* data)
{
RegisterID* unused = newTemporary();
ASSERT(completionTypeRegister);
emitOutOfLineExceptionHandler(exceptionRegister, unused, completionTypeRegister, data);
}
void BytecodeGenerator::emitOutOfLineExceptionHandler(RegisterID* exceptionRegister, RegisterID* thrownValueRegister, RegisterID* completionTypeRegister, TryData* data)
{
VirtualRegister completionTypeVirtualRegister = completionTypeRegister ? completionTypeRegister : VirtualRegister();
m_exceptionHandlersToEmit.append({ data, exceptionRegister, thrownValueRegister, completionTypeVirtualRegister });
}
void BytecodeGenerator::restoreScopeRegister(int lexicalScopeIndex)
{
if (lexicalScopeIndex == CurrentLexicalScopeIndex)
return; // No change needed.
if (lexicalScopeIndex != OutermostLexicalScopeIndex) {
ASSERT(lexicalScopeIndex < static_cast<int>(m_lexicalScopeStack.size()));
int endIndex = lexicalScopeIndex + 1;
for (size_t i = endIndex; i--; ) {
if (m_lexicalScopeStack[i].m_scope) {
move(scopeRegister(), m_lexicalScopeStack[i].m_scope);
return;
}
}
}
// Note that if we don't find a local scope in the current function/program,
// we must grab the outer-most scope of this bytecode generation.
move(scopeRegister(), m_topMostScope);
}
void BytecodeGenerator::restoreScopeRegister()
{
restoreScopeRegister(currentLexicalScopeIndex());
}
int BytecodeGenerator::labelScopeDepthToLexicalScopeIndex(int targetLabelScopeDepth)
{
ASSERT(labelScopeDepth() - targetLabelScopeDepth >= 0);
size_t scopeDelta = labelScopeDepth() - targetLabelScopeDepth;
ASSERT(scopeDelta <= m_controlFlowScopeStack.size());
if (!scopeDelta)
return CurrentLexicalScopeIndex;
ControlFlowScope& targetScope = m_controlFlowScopeStack[targetLabelScopeDepth];
return targetScope.lexicalScopeIndex;
}
void BytecodeGenerator::emitThrow(RegisterID* exc)
{
m_usesExceptions = true;
OpThrow::emit(this, exc);
}
RegisterID* BytecodeGenerator::emitArgumentCount(RegisterID* dst)
{
OpArgumentCount::emit(this, dst);
return dst;
}
unsigned BytecodeGenerator::localScopeDepth() const
{
return m_localScopeDepth;
}
int BytecodeGenerator::labelScopeDepth() const
{
unsigned depth = localScopeDepth() + m_finallyDepth;
ASSERT(depth == m_controlFlowScopeStack.size());
return depth;
}
void BytecodeGenerator::emitThrowStaticError(ErrorType errorType, RegisterID* raw)
{
RefPtr<RegisterID> message = newTemporary();
emitToString(message.get(), raw);
OpThrowStaticError::emit(this, message.get(), errorType);
}
void BytecodeGenerator::emitThrowStaticError(ErrorType errorType, const Identifier& message)
{
OpThrowStaticError::emit(this, addConstantValue(addStringConstant(message)), errorType);
}
void BytecodeGenerator::emitThrowReferenceError(const String& message)
{
emitThrowStaticError(ErrorType::ReferenceError, Identifier::fromString(m_vm, message));
}
void BytecodeGenerator::emitThrowTypeError(const String& message)
{
emitThrowStaticError(ErrorType::TypeError, Identifier::fromString(m_vm, message));
}
void BytecodeGenerator::emitThrowTypeError(const Identifier& message)
{
emitThrowStaticError(ErrorType::TypeError, message);
}
void BytecodeGenerator::emitThrowRangeError(const Identifier& message)
{
emitThrowStaticError(ErrorType::RangeError, message);
}
void BytecodeGenerator::emitThrowOutOfMemoryError()
{
emitThrowStaticError(ErrorType::Error, Identifier::fromString(m_vm, "Out of memory"));
}
void BytecodeGenerator::emitPushFunctionNameScope(const Identifier& property, RegisterID* callee, bool isCaptured)
{
// There is some nuance here:
// If we're in strict mode code, the function name scope variable acts exactly like a "const" variable.
// If we're not in strict mode code, we want to allow bogus assignments to the name scoped variable.
// This means any assignment to the variable won't throw, but it won't actually assign a new value to it.
// To accomplish this, we don't report that this scope is a lexical scope. This will prevent
// any throws when trying to assign to the variable (while still ensuring it keeps its original
// value). There is some ugliness and exploitation of a leaky abstraction here, but it's better than
// having a completely new op code and a class to handle name scopes which are so close in functionality
// to lexical environments.
VariableEnvironment nameScopeEnvironment;
auto addResult = nameScopeEnvironment.add(property);
if (isCaptured)
addResult.iterator->value.setIsCaptured();
addResult.iterator->value.setIsConst(); // The function name scope name acts like a const variable.
unsigned numVars = m_codeBlock->m_numVars;
pushLexicalScopeInternal(nameScopeEnvironment, TDZCheckOptimization::Optimize, NestedScopeType::IsNotNested, nullptr, TDZRequirement::NotUnderTDZ, ScopeType::FunctionNameScope, ScopeRegisterType::Var);
ASSERT_UNUSED(numVars, m_codeBlock->m_numVars == static_cast<int>(numVars + 1)); // Should have only created one new "var" for the function name scope.
bool shouldTreatAsLexicalVariable = isStrictMode();
Variable functionVar = variableForLocalEntry(property, m_lexicalScopeStack.last().m_symbolTable->get(NoLockingNecessary, property.impl()), m_lexicalScopeStack.last().m_symbolTableConstantIndex, shouldTreatAsLexicalVariable);
emitPutToScope(m_lexicalScopeStack.last().m_scope, functionVar, callee, ThrowIfNotFound, InitializationMode::NotInitialization);
}
void BytecodeGenerator::pushLocalControlFlowScope()
{
ControlFlowScope scope(ControlFlowScope::Label, currentLexicalScopeIndex());
m_controlFlowScopeStack.append(WTFMove(scope));
m_localScopeDepth++;
}
void BytecodeGenerator::popLocalControlFlowScope()
{
ASSERT(m_controlFlowScopeStack.size());
ASSERT(!m_controlFlowScopeStack.last().isFinallyScope());
m_controlFlowScopeStack.removeLast();
m_localScopeDepth--;
}
void BytecodeGenerator::emitPushCatchScope(VariableEnvironment& environment)
{
pushLexicalScopeInternal(environment, TDZCheckOptimization::Optimize, NestedScopeType::IsNotNested, nullptr, TDZRequirement::UnderTDZ, ScopeType::CatchScope, ScopeRegisterType::Block);
}
void BytecodeGenerator::emitPopCatchScope(VariableEnvironment& environment)
{
popLexicalScopeInternal(environment);
}
void BytecodeGenerator::beginSwitch(RegisterID* scrutineeRegister, SwitchInfo::SwitchType type)
{
switch (type) {
case SwitchInfo::SwitchImmediate: {
size_t tableIndex = m_codeBlock->numberOfSwitchJumpTables();
m_codeBlock->addSwitchJumpTable();
OpSwitchImm::emit(this, tableIndex, BoundLabel(), scrutineeRegister);
break;
}
case SwitchInfo::SwitchCharacter: {
size_t tableIndex = m_codeBlock->numberOfSwitchJumpTables();
m_codeBlock->addSwitchJumpTable();
OpSwitchChar::emit(this, tableIndex, BoundLabel(), scrutineeRegister);
break;
}
case SwitchInfo::SwitchString: {
size_t tableIndex = m_codeBlock->numberOfStringSwitchJumpTables();
m_codeBlock->addStringSwitchJumpTable();
OpSwitchString::emit(this, tableIndex, BoundLabel(), scrutineeRegister);
break;
}
default:
RELEASE_ASSERT_NOT_REACHED();
}
SwitchInfo info = { m_lastInstruction.offset(), type };
m_switchContextStack.append(info);
}
static int32_t keyForImmediateSwitch(ExpressionNode* node, int32_t min, int32_t max)
{
UNUSED_PARAM(max);
ASSERT(node->isNumber());
double value = static_cast<NumberNode*>(node)->value();
int32_t key = static_cast<int32_t>(value);
ASSERT(key == value);
ASSERT(key >= min);
ASSERT(key <= max);
return key - min;
}
static int32_t keyForCharacterSwitch(ExpressionNode* node, int32_t min, int32_t max)
{
UNUSED_PARAM(max);
ASSERT(node->isString());
StringImpl* clause = static_cast<StringNode*>(node)->value().impl();
ASSERT(clause->length() == 1);
int32_t key = (*clause)[0];
ASSERT(key >= min);
ASSERT(key <= max);
return key - min;
}
static void prepareJumpTableForSwitch(
UnlinkedSimpleJumpTable& jumpTable, int32_t switchAddress, uint32_t clauseCount,
const Vector<Ref<Label>, 8>& labels, ExpressionNode** nodes, int32_t min, int32_t max,
int32_t (*keyGetter)(ExpressionNode*, int32_t min, int32_t max))
{
jumpTable.min = min;
jumpTable.branchOffsets.resize(max - min + 1);
jumpTable.branchOffsets.fill(0);
for (uint32_t i = 0; i < clauseCount; ++i) {
// We're emitting this after the clause labels should have been fixed, so
// the labels should not be "forward" references
ASSERT(!labels[i]->isForward());
jumpTable.add(keyGetter(nodes[i], min, max), labels[i]->bind(switchAddress));
}
}
static void prepareJumpTableForStringSwitch(UnlinkedStringJumpTable& jumpTable, int32_t switchAddress, uint32_t clauseCount, const Vector<Ref<Label>, 8>& labels, ExpressionNode** nodes)
{
for (uint32_t i = 0; i < clauseCount; ++i) {
// We're emitting this after the clause labels should have been fixed, so
// the labels should not be "forward" references
ASSERT(!labels[i]->isForward());
ASSERT(nodes[i]->isString());
StringImpl* clause = static_cast<StringNode*>(nodes[i])->value().impl();
jumpTable.offsetTable.add(clause, UnlinkedStringJumpTable::OffsetLocation { labels[i]->bind(switchAddress) });
}
}
void BytecodeGenerator::endSwitch(uint32_t clauseCount, const Vector<Ref<Label>, 8>& labels, ExpressionNode** nodes, Label& defaultLabel, int32_t min, int32_t max)
{
SwitchInfo switchInfo = m_switchContextStack.last();
m_switchContextStack.removeLast();
BoundLabel defaultTarget = defaultLabel.bind(switchInfo.bytecodeOffset);
auto handleSwitch = [&](auto* op, auto bytecode) {
op->setDefaultOffset(defaultTarget, [&]() {
m_codeBlock->addOutOfLineJumpTarget(switchInfo.bytecodeOffset, defaultTarget);
return BoundLabel();
});
UnlinkedSimpleJumpTable& jumpTable = m_codeBlock->switchJumpTable(bytecode.m_tableIndex);
prepareJumpTableForSwitch(
jumpTable, switchInfo.bytecodeOffset, clauseCount, labels, nodes, min, max,
switchInfo.switchType == SwitchInfo::SwitchImmediate
? keyForImmediateSwitch
: keyForCharacterSwitch);
};
auto ref = m_writer.ref(switchInfo.bytecodeOffset);
switch (switchInfo.switchType) {
case SwitchInfo::SwitchImmediate: {
handleSwitch(ref->cast<OpSwitchImm>(), ref->as<OpSwitchImm>());
break;
}
case SwitchInfo::SwitchCharacter: {
handleSwitch(ref->cast<OpSwitchChar>(), ref->as<OpSwitchChar>());
break;
}
case SwitchInfo::SwitchString: {
ref->cast<OpSwitchString>()->setDefaultOffset(defaultTarget, [&]() {
m_codeBlock->addOutOfLineJumpTarget(switchInfo.bytecodeOffset, defaultTarget);
return BoundLabel();
});
UnlinkedStringJumpTable& jumpTable = m_codeBlock->stringSwitchJumpTable(ref->as<OpSwitchString>().m_tableIndex);
prepareJumpTableForStringSwitch(jumpTable, switchInfo.bytecodeOffset, clauseCount, labels, nodes);
break;
}
default:
RELEASE_ASSERT_NOT_REACHED();
break;
}
}
RegisterID* BytecodeGenerator::emitThrowExpressionTooDeepException()
{
// It would be nice to do an even better job of identifying exactly where the expression is.
// And we could make the caller pass the node pointer in, if there was some way of getting
// that from an arbitrary node. However, calling emitExpressionInfo without any useful data
// is still good enough to get us an accurate line number.
m_expressionTooDeep = true;
return newTemporary();
}
bool BytecodeGenerator::isArgumentNumber(const Identifier& ident, int argumentNumber)
{
RegisterID* registerID = variable(ident).local();
if (!registerID)
return false;
return registerID->index() == CallFrame::argumentOffset(argumentNumber);
}
bool BytecodeGenerator::emitReadOnlyExceptionIfNeeded(const Variable& variable)
{
// If we're in strict mode, we always throw.
// If we're not in strict mode, we throw for "const" variables but not the function callee.
if (isStrictMode() || variable.isConst()) {
emitThrowTypeError(Identifier::fromString(m_vm, ReadonlyPropertyWriteError));
return true;
}
return false;
}
void BytecodeGenerator::emitEnumeration(ThrowableExpressionData* node, ExpressionNode* subjectNode, const ScopedLambda<void(BytecodeGenerator&, RegisterID*)>& callBack, ForOfNode* forLoopNode, RegisterID* forLoopSymbolTable)
{
bool isForAwait = forLoopNode ? forLoopNode->isForAwait() : false;
ASSERT(!isForAwait || (isForAwait && isAsyncFunctionParseMode(parseMode())));
RefPtr<RegisterID> subject = newTemporary();
emitNode(subject.get(), subjectNode);
RefPtr<RegisterID> iterator = isForAwait ? emitGetAsyncIterator(subject.get(), node) : emitGetIterator(subject.get(), node);
RefPtr<RegisterID> nextMethod = emitGetById(newTemporary(), iterator.get(), propertyNames().next);
Ref<Label> loopDone = newLabel();
Ref<Label> tryStartLabel = newLabel();
Ref<Label> finallyViaThrowLabel = newLabel();
Ref<Label> finallyLabel = newLabel();
Ref<Label> catchLabel = newLabel();
Ref<Label> endCatchLabel = newLabel();
// RefPtr<Register> iterator's lifetime must be longer than IteratorCloseContext.
FinallyContext finallyContext(*this, finallyLabel.get());
pushFinallyControlFlowScope(finallyContext);
{
Ref<LabelScope> scope = newLabelScope(LabelScope::Loop);
RefPtr<RegisterID> value = newTemporary();
emitLoad(value.get(), jsUndefined());
emitJump(*scope->continueTarget());
Ref<Label> loopStart = newLabel();
emitLabel(loopStart.get());
emitLoopHint();
emitLabel(tryStartLabel.get());
TryData* tryData = pushTry(tryStartLabel.get(), finallyViaThrowLabel.get(), HandlerType::SynthesizedFinally);
callBack(*this, value.get());
emitJump(*scope->continueTarget());
// IteratorClose sequence for abrupt completions.
{
// Finally block for the enumeration.
emitLabel(finallyViaThrowLabel.get());
popTry(tryData, finallyViaThrowLabel.get());
Ref<Label> finallyBodyLabel = newLabel();
RefPtr<RegisterID> finallyExceptionRegister = newTemporary();
emitOutOfLineFinallyHandler(finallyContext.completionValueRegister(), finallyContext.completionTypeRegister(), tryData);
move(finallyExceptionRegister.get(), finallyContext.completionValueRegister());
emitJump(finallyBodyLabel.get());
emitLabel(finallyLabel.get());
moveEmptyValue(finallyExceptionRegister.get());
// Finally fall through case.
emitLabel(finallyBodyLabel.get());
restoreScopeRegister();
Ref<Label> finallyDone = newLabel();
RefPtr<RegisterID> returnMethod = emitGetById(newTemporary(), iterator.get(), propertyNames().returnKeyword);
emitJumpIfTrue(emitIsUndefined(newTemporary(), returnMethod.get()), finallyDone.get());
Ref<Label> returnCallTryStart = newLabel();
emitLabel(returnCallTryStart.get());
TryData* returnCallTryData = pushTry(returnCallTryStart.get(), catchLabel.get(), HandlerType::SynthesizedCatch);
CallArguments returnArguments(*this, nullptr);
move(returnArguments.thisRegister(), iterator.get());
emitCall(value.get(), returnMethod.get(), NoExpectedFunction, returnArguments, node->divot(), node->divotStart(), node->divotEnd(), DebuggableCall::No);
if (isForAwait)
emitAwait(value.get());
emitJumpIfTrue(emitIsObject(newTemporary(), value.get()), finallyDone.get());
emitThrowTypeError("Iterator result interface is not an object."_s);
emitLabel(finallyDone.get());
emitFinallyCompletion(finallyContext, endCatchLabel.get());
popTry(returnCallTryData, finallyDone.get());
// Catch block for exceptions that may be thrown while calling the return
// handler in the enumeration finally block. The only reason we need this
// catch block is because if entered the above finally block due to a thrown
// exception, then we want to re-throw the original exception on exiting
// the finally block. Otherwise, we'll let any new exception pass through.
{
emitLabel(catchLabel.get());
RefPtr<RegisterID> exceptionRegister = newTemporary();
emitOutOfLineFinallyHandler(exceptionRegister.get(), finallyContext.completionTypeRegister(), returnCallTryData);
// Since this is a synthesized catch block and we're guaranteed to never need
// to resolve any symbols from the scope, we can skip restoring the scope
// register here.
Ref<Label> throwLabel = newLabel();
emitJumpIfTrue(emitIsEmpty(newTemporary(), finallyExceptionRegister.get()), throwLabel.get());
move(exceptionRegister.get(), finallyExceptionRegister.get());
emitLabel(throwLabel.get());
emitThrow(exceptionRegister.get());
emitLabel(endCatchLabel.get());
}
}
emitLabel(*scope->continueTarget());
if (forLoopNode) {
RELEASE_ASSERT(forLoopNode->isForOfNode());
prepareLexicalScopeForNextForLoopIteration(forLoopNode, forLoopSymbolTable);
emitDebugHook(forLoopNode->lexpr());
}
{
emitIteratorNext(value.get(), nextMethod.get(), iterator.get(), node, isForAwait ? EmitAwait::Yes : EmitAwait::No);
emitJumpIfTrue(emitGetById(newTemporary(), value.get(), propertyNames().done), loopDone.get());
emitGetById(value.get(), value.get(), propertyNames().value);
emitJump(loopStart.get());
}
bool breakLabelIsBound = scope->breakTargetMayBeBound();
if (breakLabelIsBound)
emitLabel(scope->breakTarget());
popFinallyControlFlowScope();
if (breakLabelIsBound) {
// IteratorClose sequence for break-ed control flow.
emitIteratorClose(iterator.get(), node, isForAwait ? EmitAwait::Yes : EmitAwait::No);
}
}
emitLabel(loopDone.get());
}
RegisterID* BytecodeGenerator::emitGetTemplateObject(RegisterID* dst, TaggedTemplateNode* taggedTemplate)
{
TemplateObjectDescriptor::StringVector rawStrings;
TemplateObjectDescriptor::OptionalStringVector cookedStrings;
TemplateStringListNode* templateString = taggedTemplate->templateLiteral()->templateStrings();
for (; templateString; templateString = templateString->next()) {
auto* string = templateString->value();
ASSERT(string->raw());
rawStrings.append(string->raw()->impl());
if (!string->cooked())
cookedStrings.append(WTF::nullopt);
else
cookedStrings.append(string->cooked()->impl());
}
RefPtr<RegisterID> constant = addTemplateObjectConstant(TemplateObjectDescriptor::create(WTFMove(rawStrings), WTFMove(cookedStrings)), taggedTemplate->endOffset());
if (!dst)
return constant.get();
return move(dst, constant.get());
}
RegisterID* BytecodeGenerator::emitGetGlobalPrivate(RegisterID* dst, const Identifier& property)
{
dst = tempDestination(dst);
Variable var = variable(property);
if (RegisterID* local = var.local())
return move(dst, local);
RefPtr<RegisterID> scope = newTemporary();
move(scope.get(), emitResolveScope(scope.get(), var));
return emitGetFromScope(dst, scope.get(), var, ThrowIfNotFound);
}
RegisterID* BytecodeGenerator::emitGetEnumerableLength(RegisterID* dst, RegisterID* base)
{
OpGetEnumerableLength::emit(this, dst, base);
return dst;
}
RegisterID* BytecodeGenerator::emitHasGenericProperty(RegisterID* dst, RegisterID* base, RegisterID* propertyName)
{
OpHasGenericProperty::emit(this, dst, base, propertyName);
return dst;
}
RegisterID* BytecodeGenerator::emitHasIndexedProperty(RegisterID* dst, RegisterID* base, RegisterID* propertyName)
{
OpHasIndexedProperty::emit(this, dst, base, propertyName);
return dst;
}
RegisterID* BytecodeGenerator::emitHasStructureProperty(RegisterID* dst, RegisterID* base, RegisterID* propertyName, RegisterID* enumerator)
{
OpHasStructureProperty::emit(this, dst, base, propertyName, enumerator);
return dst;
}
RegisterID* BytecodeGenerator::emitGetPropertyEnumerator(RegisterID* dst, RegisterID* base)
{
OpGetPropertyEnumerator::emit(this, dst, base);
return dst;
}
RegisterID* BytecodeGenerator::emitEnumeratorStructurePropertyName(RegisterID* dst, RegisterID* enumerator, RegisterID* index)
{
OpEnumeratorStructurePname::emit(this, dst, enumerator, index);
return dst;
}
RegisterID* BytecodeGenerator::emitEnumeratorGenericPropertyName(RegisterID* dst, RegisterID* enumerator, RegisterID* index)
{
OpEnumeratorGenericPname::emit(this, dst, enumerator, index);
return dst;
}
RegisterID* BytecodeGenerator::emitToIndexString(RegisterID* dst, RegisterID* index)
{
OpToIndexString::emit(this, dst, index);
return dst;
}
RegisterID* BytecodeGenerator::emitIsCellWithType(RegisterID* dst, RegisterID* src, JSType type)
{
OpIsCellWithType::emit(this, dst, src, type);
return dst;
}
RegisterID* BytecodeGenerator::emitIsObject(RegisterID* dst, RegisterID* src)
{
OpIsObject::emit(this, dst, src);
return dst;
}
RegisterID* BytecodeGenerator::emitIsNumber(RegisterID* dst, RegisterID* src)
{
OpIsNumber::emit(this, dst, src);
return dst;
}
RegisterID* BytecodeGenerator::emitIsUndefined(RegisterID* dst, RegisterID* src)
{
OpIsUndefined::emit(this, dst, src);
return dst;
}
RegisterID* BytecodeGenerator::emitIsUndefinedOrNull(RegisterID* dst, RegisterID* src)
{
OpIsUndefinedOrNull::emit(this, dst, src);
return dst;
}
RegisterID* BytecodeGenerator::emitIsEmpty(RegisterID* dst, RegisterID* src)
{
OpIsEmpty::emit(this, dst, src);
return dst;
}
RegisterID* BytecodeGenerator::emitIteratorNext(RegisterID* dst, RegisterID* nextMethod, RegisterID* iterator, const ThrowableExpressionData* node, EmitAwait doEmitAwait)
{
{
CallArguments nextArguments(*this, nullptr);
move(nextArguments.thisRegister(), iterator);
emitCall(dst, nextMethod, NoExpectedFunction, nextArguments, node->divot(), node->divotStart(), node->divotEnd(), DebuggableCall::No);
if (doEmitAwait == EmitAwait::Yes)
emitAwait(dst);
}
{
Ref<Label> typeIsObject = newLabel();
emitJumpIfTrue(emitIsObject(newTemporary(), dst), typeIsObject.get());
emitThrowTypeError("Iterator result interface is not an object."_s);
emitLabel(typeIsObject.get());
}
return dst;
}
RegisterID* BytecodeGenerator::emitIteratorNextWithValue(RegisterID* dst, RegisterID* nextMethod, RegisterID* iterator, RegisterID* value, const ThrowableExpressionData* node)
{
{
CallArguments nextArguments(*this, nullptr, 1);
move(nextArguments.thisRegister(), iterator);
move(nextArguments.argumentRegister(0), value);
emitCall(dst, nextMethod, NoExpectedFunction, nextArguments, node->divot(), node->divotStart(), node->divotEnd(), DebuggableCall::No);
}
return dst;
}
void BytecodeGenerator::emitIteratorClose(RegisterID* iterator, const ThrowableExpressionData* node, EmitAwait doEmitAwait)
{
Ref<Label> done = newLabel();
RefPtr<RegisterID> returnMethod = emitGetById(newTemporary(), iterator, propertyNames().returnKeyword);
emitJumpIfTrue(emitIsUndefined(newTemporary(), returnMethod.get()), done.get());
RefPtr<RegisterID> value = newTemporary();
CallArguments returnArguments(*this, nullptr);
move(returnArguments.thisRegister(), iterator);
emitCall(value.get(), returnMethod.get(), NoExpectedFunction, returnArguments, node->divot(), node->divotStart(), node->divotEnd(), DebuggableCall::No);
if (doEmitAwait == EmitAwait::Yes)
emitAwait(value.get());
emitJumpIfTrue(emitIsObject(newTemporary(), value.get()), done.get());
emitThrowTypeError("Iterator result interface is not an object."_s);
emitLabel(done.get());
}
void BytecodeGenerator::pushIndexedForInScope(RegisterID* localRegister, RegisterID* indexRegister)
{
if (!localRegister)
return;
unsigned bodyBytecodeStartOffset = instructions().size();
m_forInContextStack.append(adoptRef(*new IndexedForInContext(localRegister, indexRegister, bodyBytecodeStartOffset)));
}
void BytecodeGenerator::popIndexedForInScope(RegisterID* localRegister)
{
if (!localRegister)
return;
unsigned bodyBytecodeEndOffset = instructions().size();
m_forInContextStack.last()->asIndexedForInContext().finalize(*this, m_codeBlock.get(), bodyBytecodeEndOffset);
m_forInContextStack.removeLast();
}
RegisterID* BytecodeGenerator::emitLoadArrowFunctionLexicalEnvironment(const Identifier& identifier)
{
ASSERT(m_codeBlock->isArrowFunction() || m_codeBlock->isArrowFunctionContext() || constructorKind() == ConstructorKind::Extends || m_codeType == EvalCode);
return emitResolveScope(nullptr, variable(identifier, ThisResolutionType::Scoped));
}
void BytecodeGenerator::emitLoadThisFromArrowFunctionLexicalEnvironment()
{
emitGetFromScope(thisRegister(), emitLoadArrowFunctionLexicalEnvironment(propertyNames().thisIdentifier), variable(propertyNames().thisIdentifier, ThisResolutionType::Scoped), DoNotThrowIfNotFound);
}
RegisterID* BytecodeGenerator::emitLoadNewTargetFromArrowFunctionLexicalEnvironment()
{
Variable newTargetVar = variable(propertyNames().builtinNames().newTargetLocalPrivateName());
return emitGetFromScope(m_newTargetRegister, emitLoadArrowFunctionLexicalEnvironment(propertyNames().builtinNames().newTargetLocalPrivateName()), newTargetVar, ThrowIfNotFound);
}
RegisterID* BytecodeGenerator::emitLoadDerivedConstructorFromArrowFunctionLexicalEnvironment()
{
Variable protoScopeVar = variable(propertyNames().builtinNames().derivedConstructorPrivateName());
return emitGetFromScope(newTemporary(), emitLoadArrowFunctionLexicalEnvironment(propertyNames().builtinNames().derivedConstructorPrivateName()), protoScopeVar, ThrowIfNotFound);
}
RegisterID* BytecodeGenerator::ensureThis()
{
if (constructorKind() == ConstructorKind::Extends || isDerivedConstructorContext()) {
if ((needsToUpdateArrowFunctionContext() && isSuperCallUsedInInnerArrowFunction()) || m_codeBlock->parseMode() == SourceParseMode::AsyncArrowFunctionBodyMode)
emitLoadThisFromArrowFunctionLexicalEnvironment();
emitTDZCheck(thisRegister());
}
return thisRegister();
}
bool BytecodeGenerator::isThisUsedInInnerArrowFunction()
{
return m_scopeNode->doAnyInnerArrowFunctionsUseThis() || m_scopeNode->doAnyInnerArrowFunctionsUseSuperProperty() || m_scopeNode->doAnyInnerArrowFunctionsUseSuperCall() || m_scopeNode->doAnyInnerArrowFunctionsUseEval() || m_codeBlock->usesEval();
}
bool BytecodeGenerator::isArgumentsUsedInInnerArrowFunction()
{
return m_scopeNode->doAnyInnerArrowFunctionsUseArguments() || m_scopeNode->doAnyInnerArrowFunctionsUseEval();
}
bool BytecodeGenerator::isNewTargetUsedInInnerArrowFunction()
{
return m_scopeNode->doAnyInnerArrowFunctionsUseNewTarget() || m_scopeNode->doAnyInnerArrowFunctionsUseSuperCall() || m_scopeNode->doAnyInnerArrowFunctionsUseEval() || m_codeBlock->usesEval();
}
bool BytecodeGenerator::isSuperUsedInInnerArrowFunction()
{
return m_scopeNode->doAnyInnerArrowFunctionsUseSuperCall() || m_scopeNode->doAnyInnerArrowFunctionsUseSuperProperty() || m_scopeNode->doAnyInnerArrowFunctionsUseEval() || m_codeBlock->usesEval();
}
bool BytecodeGenerator::isSuperCallUsedInInnerArrowFunction()
{
return m_scopeNode->doAnyInnerArrowFunctionsUseSuperCall() || m_scopeNode->doAnyInnerArrowFunctionsUseEval() || m_codeBlock->usesEval();
}
void BytecodeGenerator::emitPutNewTargetToArrowFunctionContextScope()
{
if (isNewTargetUsedInInnerArrowFunction()) {
ASSERT(m_arrowFunctionContextLexicalEnvironmentRegister);
Variable newTargetVar = variable(propertyNames().builtinNames().newTargetLocalPrivateName());
emitPutToScope(m_arrowFunctionContextLexicalEnvironmentRegister, newTargetVar, newTarget(), DoNotThrowIfNotFound, InitializationMode::Initialization);
}
}
void BytecodeGenerator::emitPutDerivedConstructorToArrowFunctionContextScope()
{
if (needsDerivedConstructorInArrowFunctionLexicalEnvironment()) {
ASSERT(m_arrowFunctionContextLexicalEnvironmentRegister);
Variable protoScope = variable(propertyNames().builtinNames().derivedConstructorPrivateName());
emitPutToScope(m_arrowFunctionContextLexicalEnvironmentRegister, protoScope, &m_calleeRegister, DoNotThrowIfNotFound, InitializationMode::Initialization);
}
}
void BytecodeGenerator::emitPutThisToArrowFunctionContextScope()
{
if (isThisUsedInInnerArrowFunction() || (m_scopeNode->usesSuperCall() && m_codeType == EvalCode)) {
ASSERT(isDerivedConstructorContext() || m_arrowFunctionContextLexicalEnvironmentRegister != nullptr);
Variable thisVar = variable(propertyNames().thisIdentifier, ThisResolutionType::Scoped);
RegisterID* scope = isDerivedConstructorContext() ? emitLoadArrowFunctionLexicalEnvironment(propertyNames().thisIdentifier) : m_arrowFunctionContextLexicalEnvironmentRegister;
emitPutToScope(scope, thisVar, thisRegister(), ThrowIfNotFound, InitializationMode::NotInitialization);
}
}
void BytecodeGenerator::pushStructureForInScope(RegisterID* localRegister, RegisterID* indexRegister, RegisterID* propertyRegister, RegisterID* enumeratorRegister)
{
if (!localRegister)
return;
unsigned bodyBytecodeStartOffset = instructions().size();
m_forInContextStack.append(adoptRef(*new StructureForInContext(localRegister, indexRegister, propertyRegister, enumeratorRegister, bodyBytecodeStartOffset)));
}
void BytecodeGenerator::popStructureForInScope(RegisterID* localRegister)
{
if (!localRegister)
return;
unsigned bodyBytecodeEndOffset = instructions().size();
m_forInContextStack.last()->asStructureForInContext().finalize(*this, m_codeBlock.get(), bodyBytecodeEndOffset);
m_forInContextStack.removeLast();
}
RegisterID* BytecodeGenerator::emitRestParameter(RegisterID* result, unsigned numParametersToSkip)
{
RefPtr<RegisterID> restArrayLength = newTemporary();
OpGetRestLength::emit(this, restArrayLength.get(), numParametersToSkip);
OpCreateRest::emit(this, result, restArrayLength.get(), numParametersToSkip);
return result;
}
void BytecodeGenerator::emitRequireObjectCoercible(RegisterID* value, const String& error)
{
Ref<Label> target = newLabel();
OpJnundefinedOrNull::emit(this, value, target->bind(this));
emitThrowTypeError(error);
emitLabel(target.get());
}
void BytecodeGenerator::emitYieldPoint(RegisterID* argument, JSAsyncGenerator::AsyncGeneratorSuspendReason result)
{
Ref<Label> mergePoint = newLabel();
unsigned yieldPointIndex = m_yieldPoints++;
emitGeneratorStateChange(yieldPointIndex + 1);
if (parseMode() == SourceParseMode::AsyncGeneratorBodyMode) {
int suspendReason = static_cast<int32_t>(result);
emitPutInternalField(generatorRegister(), static_cast<unsigned>(JSAsyncGenerator::Field::SuspendReason), emitLoad(nullptr, jsNumber(suspendReason)));
}
// Split the try range here.
Ref<Label> savePoint = newEmittedLabel();
for (unsigned i = m_tryContextStack.size(); i--;) {
TryContext& context = m_tryContextStack[i];
m_tryRanges.append(TryRange {
context.start.copyRef(),
savePoint.copyRef(),
context.tryData
});
// Try range will be restared at the merge point.
context.start = mergePoint.get();
}
Vector<TryContext> savedTryContextStack;
m_tryContextStack.swap(savedTryContextStack);
#if CPU(NEEDS_ALIGNED_ACCESS)
// conservatively align for the bytecode rewriter: it will delete this yield and
// append a fragment, so we make sure that the start of the fragments is aligned
while (m_writer.position() % OpcodeSize::Wide32)
OpNop::emit<OpcodeSize::Narrow>(this);
#endif
OpYield::emit(this, generatorFrameRegister(), yieldPointIndex, argument);
// Restore the try contexts, which start offset is updated to the merge point.
m_tryContextStack.swap(savedTryContextStack);
emitLabel(mergePoint.get());
}
RegisterID* BytecodeGenerator::emitYield(RegisterID* argument, JSAsyncGenerator::AsyncGeneratorSuspendReason result)
{
emitYieldPoint(argument, result);
Ref<Label> normalLabel = newLabel();
RefPtr<RegisterID> condition = newTemporary();
emitEqualityOp<OpStricteq>(condition.get(), generatorResumeModeRegister(), emitLoad(nullptr, jsNumber(static_cast<int32_t>(JSGenerator::GeneratorResumeMode::NormalMode))));
emitJumpIfTrue(condition.get(), normalLabel.get());
Ref<Label> throwLabel = newLabel();
emitEqualityOp<OpStricteq>(condition.get(), generatorResumeModeRegister(), emitLoad(nullptr, jsNumber(static_cast<int32_t>(JSGenerator::GeneratorResumeMode::ThrowMode))));
emitJumpIfTrue(condition.get(), throwLabel.get());
// Return.
{
RefPtr<RegisterID> returnRegister = generatorValueRegister();
bool hasFinally = emitReturnViaFinallyIfNeeded(returnRegister.get());
if (!hasFinally)
emitReturn(returnRegister.get());
}
// Throw.
emitLabel(throwLabel.get());
emitThrow(generatorValueRegister());
// Normal.
emitLabel(normalLabel.get());
return generatorValueRegister();
}
RegisterID* BytecodeGenerator::emitCallIterator(RegisterID* iterator, RegisterID* argument, ThrowableExpressionData* node)
{
CallArguments args(*this, nullptr);
move(args.thisRegister(), argument);
emitCall(iterator, iterator, NoExpectedFunction, args, node->divot(), node->divotStart(), node->divotEnd(), DebuggableCall::No);
return iterator;
}
void BytecodeGenerator::emitAwait(RegisterID* value)
{
emitYield(value, JSAsyncGenerator::AsyncGeneratorSuspendReason::Await);
move(value, generatorValueRegister());
}
RegisterID* BytecodeGenerator::emitGetIterator(RegisterID* argument, ThrowableExpressionData* node)
{
RefPtr<RegisterID> iterator = emitGetById(newTemporary(), argument, propertyNames().iteratorSymbol);
emitCallIterator(iterator.get(), argument, node);
return iterator.get();
}
RegisterID* BytecodeGenerator::emitGetAsyncIterator(RegisterID* argument, ThrowableExpressionData* node)
{
RefPtr<RegisterID> iterator = emitGetById(newTemporary(), argument, propertyNames().asyncIteratorSymbol);
Ref<Label> asyncIteratorNotFound = newLabel();
Ref<Label> asyncIteratorFound = newLabel();
Ref<Label> iteratorReceived = newLabel();
emitJumpIfTrue(emitUnaryOp<OpEqNull>(newTemporary(), iterator.get()), asyncIteratorNotFound.get());
emitJump(asyncIteratorFound.get());
emitLabel(asyncIteratorNotFound.get());
RefPtr<RegisterID> commonIterator = emitGetIterator(argument, node);
move(iterator.get(), commonIterator.get());
RefPtr<RegisterID> nextMethod = emitGetById(newTemporary(), iterator.get(), propertyNames().next);
RefPtr<RegisterID> createAsyncFromSyncIterator = moveLinkTimeConstant(nullptr, LinkTimeConstant::createAsyncFromSyncIterator);
CallArguments args(*this, nullptr, 2);
emitLoad(args.thisRegister(), jsUndefined());
move(args.argumentRegister(0), iterator.get());
move(args.argumentRegister(1), nextMethod.get());
JSTextPosition divot(m_scopeNode->firstLine(), m_scopeNode->startOffset(), m_scopeNode->lineStartOffset());
emitCall(iterator.get(), createAsyncFromSyncIterator.get(), NoExpectedFunction, args, divot, divot, divot, DebuggableCall::No);
emitJump(iteratorReceived.get());
emitLabel(asyncIteratorFound.get());
emitCallIterator(iterator.get(), argument, node);
emitLabel(iteratorReceived.get());
return iterator.get();
}
RegisterID* BytecodeGenerator::emitDelegateYield(RegisterID* argument, ThrowableExpressionData* node)
{
RefPtr<RegisterID> value = newTemporary();
{
RefPtr<RegisterID> iterator = parseMode() == SourceParseMode::AsyncGeneratorBodyMode ? emitGetAsyncIterator(argument, node) : emitGetIterator(argument, node);
RefPtr<RegisterID> nextMethod = emitGetById(newTemporary(), iterator.get(), propertyNames().next);
Ref<Label> loopDone = newLabel();
{
Ref<Label> nextElement = newLabel();
emitLoad(value.get(), jsUndefined());
emitJump(nextElement.get());
Ref<Label> loopStart = newLabel();
emitLabel(loopStart.get());
emitLoopHint();
Ref<Label> branchOnResult = newLabel();
{
emitYieldPoint(value.get(), JSAsyncGenerator::AsyncGeneratorSuspendReason::Yield);
Ref<Label> normalLabel = newLabel();
Ref<Label> returnLabel = newLabel();
{
RefPtr<RegisterID> condition = newTemporary();
emitEqualityOp<OpStricteq>(condition.get(), generatorResumeModeRegister(), emitLoad(nullptr, jsNumber(static_cast<int32_t>(JSGenerator::GeneratorResumeMode::NormalMode))));
emitJumpIfTrue(condition.get(), normalLabel.get());
emitEqualityOp<OpStricteq>(condition.get(), generatorResumeModeRegister(), emitLoad(nullptr, jsNumber(static_cast<int32_t>(JSGenerator::GeneratorResumeMode::ReturnMode))));
emitJumpIfTrue(condition.get(), returnLabel.get());
// Fallthrough to ThrowMode.
}
// Throw.
{
Ref<Label> throwMethodFound = newLabel();
RefPtr<RegisterID> throwMethod = emitGetById(newTemporary(), iterator.get(), propertyNames().throwKeyword);
emitJumpIfFalse(emitIsUndefined(newTemporary(), throwMethod.get()), throwMethodFound.get());
EmitAwait emitAwaitInIteratorClose = parseMode() == SourceParseMode::AsyncGeneratorBodyMode ? EmitAwait::Yes : EmitAwait::No;
emitIteratorClose(iterator.get(), node, emitAwaitInIteratorClose);
emitThrowTypeError("Delegated generator does not have a 'throw' method."_s);
emitLabel(throwMethodFound.get());
CallArguments throwArguments(*this, nullptr, 1);
move(throwArguments.thisRegister(), iterator.get());
move(throwArguments.argumentRegister(0), generatorValueRegister());
emitCall(value.get(), throwMethod.get(), NoExpectedFunction, throwArguments, node->divot(), node->divotStart(), node->divotEnd(), DebuggableCall::No);
emitJump(branchOnResult.get());
}
// Return.
emitLabel(returnLabel.get());
{
Ref<Label> returnMethodFound = newLabel();
RefPtr<RegisterID> returnMethod = emitGetById(newTemporary(), iterator.get(), propertyNames().returnKeyword);
emitJumpIfFalse(emitIsUndefined(newTemporary(), returnMethod.get()), returnMethodFound.get());
move(value.get(), generatorValueRegister());
Ref<Label> returnSequence = newLabel();
emitJump(returnSequence.get());
emitLabel(returnMethodFound.get());
CallArguments returnArguments(*this, nullptr, 1);
move(returnArguments.thisRegister(), iterator.get());
move(returnArguments.argumentRegister(0), generatorValueRegister());
emitCall(value.get(), returnMethod.get(), NoExpectedFunction, returnArguments, node->divot(), node->divotStart(), node->divotEnd(), DebuggableCall::No);
if (parseMode() == SourceParseMode::AsyncGeneratorBodyMode)
emitAwait(value.get());
Ref<Label> returnIteratorResultIsObject = newLabel();
emitJumpIfTrue(emitIsObject(newTemporary(), value.get()), returnIteratorResultIsObject.get());
emitThrowTypeError("Iterator result interface is not an object."_s);
emitLabel(returnIteratorResultIsObject.get());
Ref<Label> returnFromGenerator = newLabel();
emitJumpIfTrue(emitGetById(newTemporary(), value.get(), propertyNames().done), returnFromGenerator.get());
emitGetById(value.get(), value.get(), propertyNames().value);
emitJump(loopStart.get());
emitLabel(returnFromGenerator.get());
emitGetById(value.get(), value.get(), propertyNames().value);
emitLabel(returnSequence.get());
bool hasFinally = emitReturnViaFinallyIfNeeded(value.get());
if (!hasFinally)
emitReturn(value.get());
}
// Normal.
emitLabel(normalLabel.get());
move(value.get(), generatorValueRegister());
}
emitLabel(nextElement.get());
emitIteratorNextWithValue(value.get(), nextMethod.get(), iterator.get(), value.get(), node);
emitLabel(branchOnResult.get());
if (parseMode() == SourceParseMode::AsyncGeneratorBodyMode)
emitAwait(value.get());
Ref<Label> iteratorValueIsObject = newLabel();
emitJumpIfTrue(emitIsObject(newTemporary(), value.get()), iteratorValueIsObject.get());
emitThrowTypeError("Iterator result interface is not an object."_s);
emitLabel(iteratorValueIsObject.get());
emitJumpIfTrue(emitGetById(newTemporary(), value.get(), propertyNames().done), loopDone.get());
emitGetById(value.get(), value.get(), propertyNames().value);
emitJump(loopStart.get());
}
emitLabel(loopDone.get());
}
emitGetById(value.get(), value.get(), propertyNames().value);
return value.get();
}
void BytecodeGenerator::emitGeneratorStateChange(int32_t state)
{
RegisterID* completedState = emitLoad(nullptr, jsNumber(state));
static_assert(static_cast<unsigned>(JSGenerator::Field::State) == static_cast<unsigned>(JSAsyncGenerator::Field::State));
emitPutInternalField(generatorRegister(), static_cast<unsigned>(JSGenerator::Field::State), completedState);
}
bool BytecodeGenerator::emitJumpViaFinallyIfNeeded(int targetLabelScopeDepth, Label& jumpTarget)
{
ASSERT(labelScopeDepth() - targetLabelScopeDepth >= 0);
size_t numberOfScopesToCheckForFinally = labelScopeDepth() - targetLabelScopeDepth;
ASSERT(numberOfScopesToCheckForFinally <= m_controlFlowScopeStack.size());
if (!numberOfScopesToCheckForFinally)
return false;
FinallyContext* innermostFinallyContext = nullptr;
FinallyContext* outermostFinallyContext = nullptr;
size_t scopeIndex = m_controlFlowScopeStack.size() - 1;
while (numberOfScopesToCheckForFinally--) {
ControlFlowScope* scope = &m_controlFlowScopeStack[scopeIndex--];
if (scope->isFinallyScope()) {
FinallyContext* finallyContext = scope->finallyContext;
if (!innermostFinallyContext)
innermostFinallyContext = finallyContext;
outermostFinallyContext = finallyContext;
finallyContext->incNumberOfBreaksOrContinues();
}
}
if (!outermostFinallyContext)
return false; // No finallys to thread through.
auto jumpID = bytecodeOffsetToJumpID(instructions().size());
int lexicalScopeIndex = labelScopeDepthToLexicalScopeIndex(targetLabelScopeDepth);
outermostFinallyContext->registerJump(jumpID, lexicalScopeIndex, jumpTarget);
emitLoad(innermostFinallyContext->completionTypeRegister(), jumpID);
emitJump(*innermostFinallyContext->finallyLabel());
return true; // We'll be jumping to a finally block.
}
bool BytecodeGenerator::emitReturnViaFinallyIfNeeded(RegisterID* returnRegister)
{
size_t numberOfScopesToCheckForFinally = m_controlFlowScopeStack.size();
if (!numberOfScopesToCheckForFinally)
return false;
FinallyContext* innermostFinallyContext = nullptr;
while (numberOfScopesToCheckForFinally) {
size_t scopeIndex = --numberOfScopesToCheckForFinally;
ControlFlowScope* scope = &m_controlFlowScopeStack[scopeIndex];
if (scope->isFinallyScope()) {
FinallyContext* finallyContext = scope->finallyContext;
if (!innermostFinallyContext)
innermostFinallyContext = finallyContext;
finallyContext->setHandlesReturns();
}
}
if (!innermostFinallyContext)
return false; // No finallys to thread through.
emitLoad(innermostFinallyContext->completionTypeRegister(), CompletionType::Return);
move(innermostFinallyContext->completionValueRegister(), returnRegister);
emitJump(*innermostFinallyContext->finallyLabel());
return true; // We'll be jumping to a finally block.
}
void BytecodeGenerator::emitFinallyCompletion(FinallyContext& context, Label& normalCompletionLabel)
{
if (context.numberOfBreaksOrContinues() || context.handlesReturns()) {
emitJumpIf<OpStricteq>(context.completionTypeRegister(), CompletionType::Normal, normalCompletionLabel);
FinallyContext* outerContext = context.outerContext();
size_t numberOfJumps = context.numberOfJumps();
ASSERT(outerContext || numberOfJumps == context.numberOfBreaksOrContinues());
// Handle Break or Continue completions that jumps into this FinallyContext.
for (size_t i = 0; i < numberOfJumps; i++) {
Ref<Label> nextLabel = newLabel();
auto& jump = context.jumps(i);
emitJumpIf<OpNstricteq>(context.completionTypeRegister(), jump.jumpID, nextLabel.get());
// This case is for Break / Continue completions from an inner finally context
// with a jump target that is not beyond the next outer finally context:
//
// try {
// for (... stuff ...) {
// try {
// continue; // Sets completionType to jumpID of top of the for loop.
// } finally {
// } // Jump to top of the for loop on completion.
// }
// } finally {
// }
//
// Since the jumpID is targetting a label that is inside the outer finally context,
// we can jump to it directly on completion of this finally context: there is no intermediate
// finally blocks to run. After the Break / Continue, we will contnue execution as normal.
// So, we'll set the completionType to Normal (on behalf of the target) before we jump.
// We can also set the completion value to undefined, but it will never be used for normal
// completion anyway. So, we'll skip setting it.
restoreScopeRegister(jump.targetLexicalScopeIndex);
emitLoad(context.completionTypeRegister(), CompletionType::Normal);
emitJump(jump.targetLabel.get());
emitLabel(nextLabel.get());
}
// Handle completions that take us out of this FinallyContext.
if (outerContext) {
if (context.handlesReturns()) {
Ref<Label> isNotReturnLabel = newLabel();
emitJumpIf<OpNstricteq>(context.completionTypeRegister(), CompletionType::Return, isNotReturnLabel.get());
// This case is for Return completion from an inner finally context:
//
// try {
// try {
// return result; // Sets completionType to Return, and completionValue to result.
// } finally {
// } // Jump to outer finally on completion.
// } finally {
// }
//
// Since we know there's at least one outer finally context (beyond the current context),
// we cannot actually return from here. Instead, we pass the completionType and completionValue
// on to the next outer finally, and let it decide what to do next on its completion. The
// outer finally may or may not actual return depending on whether it encounters an abrupt
// completion in its body that overrrides this Return completion.
move(outerContext->completionTypeRegister(), context.completionTypeRegister());
move(outerContext->completionValueRegister(), context.completionValueRegister());
emitJump(*outerContext->finallyLabel());
emitLabel(isNotReturnLabel.get());
}
bool hasBreaksOrContinuesThatEscapeCurrentFinally = context.numberOfBreaksOrContinues() > numberOfJumps;
if (hasBreaksOrContinuesThatEscapeCurrentFinally) {
Ref<Label> isThrowOrNormalLabel = newLabel();
emitJumpIf<OpBeloweq>(context.completionTypeRegister(), CompletionType::Throw, isThrowOrNormalLabel.get());
// A completionType above Throw means we have a Break or Continue encoded as a jumpID.
// We already ruled out Return above.
static_assert(CompletionType::Throw < CompletionType::Return && CompletionType::Throw < CompletionType::Return, "jumpIDs are above CompletionType::Return");
// This case is for Break / Continue completions in an inner finally context:
//
// 10: label:
// 11: try {
// 12: try {
// 13: for (... stuff ...)
// 14: break label; // Sets completionType to jumpID of label.
// 15: } finally {
// 16: } // Jumps to outer finally on completion.
// 17: } finally {
// 18: }
//
// The break (line 14) says to continue execution at the label at line 10. Before we can
// goto line 10, the inner context's finally (line 15) needs to be run, followed by the
// outer context's finally (line 17). 'outerContext' being non-null above tells us that
// there is at least one outer finally context that we need to run after we complete the
// current finally. Note that unless the body of the outer finally abruptly completes in a
// different way, that outer finally also needs to complete with a Break / Continue to
// the same target label. Hence, we need to pass the jumpID in this finally's completionTypeRegister
// to the outer finally. The completion value for Break and Continue according to the spec
// is undefined, but it won't ever be used. So, we'll skip setting it.
//
// Note that all we're doing here is passing the Break / Continue completion to the next
// outer finally context. We don't worry about finally contexts beyond that. It is the
// responsibility of the next outer finally to determine what to do next at its completion,
// and pass on to the next outer context if present and needed.
move(outerContext->completionTypeRegister(), context.completionTypeRegister());
emitJump(*outerContext->finallyLabel());
emitLabel(isThrowOrNormalLabel.get());
}
} else {
// We are the outermost finally.
if (context.handlesReturns()) {
Ref<Label> notReturnLabel = newLabel();
emitJumpIf<OpNstricteq>(context.completionTypeRegister(), CompletionType::Return, notReturnLabel.get());
// This case is for Return completion from the outermost finally context:
//
// try {
// return result; // Sets completionType to Return, and completionValue to result.
// } finally {
// } // Executes the return of the completionValue.
//
// Since we know there's no outer finally context (beyond the current context) to run,
// we can actually execute a return for this Return completion. The value to return
// is whatever is in the completionValueRegister.
emitWillLeaveCallFrameDebugHook();
emitReturn(context.completionValueRegister(), ReturnFrom::Finally);
emitLabel(notReturnLabel.get());
}
}
}
// By now, we've rule out all Break / Continue / Return completions above. The only remaining
// possibilities are Normal or Throw.
emitJumpIf<OpNstricteq>(context.completionTypeRegister(), CompletionType::Throw, normalCompletionLabel);
// We get here because we entered this finally context with Throw completionType (i.e. we have
// an exception that we need to rethrow), and we didn't encounter a different abrupt completion
// that overrides that incoming completionType. All we have to do here is re-throw the exception
// captured in the completionValue.
//
// Note that unlike for Break / Continue / Return, we don't need to worry about outer finally
// contexts. This is because any outer finally context (if present) will have its own exception
// handler, which will take care of receiving the Throw completion, and re-capturing the exception
// in its completionValue.
emitThrow(context.completionValueRegister());
}
template<typename CompareOp>
void BytecodeGenerator::emitJumpIf(RegisterID* completionTypeRegister, CompletionType type, Label& jumpTarget)
{
RefPtr<RegisterID> tempRegister = newTemporary();
RegisterID* valueConstant = addConstantValue(jsNumber(static_cast<int>(type)));
OperandTypes operandTypes = OperandTypes(ResultType::numberTypeIsInt32(), ResultType::unknownType());
auto equivalenceResult = emitBinaryOp<CompareOp>(tempRegister.get(), completionTypeRegister, valueConstant, operandTypes);
emitJumpIfTrue(equivalenceResult, jumpTarget);
}
void BytecodeGenerator::pushOptionalChainTarget()
{
m_optionalChainTargetStack.append(newLabel());
}
void BytecodeGenerator::popOptionalChainTarget()
{
ASSERT(m_optionalChainTargetStack.size());
emitLabel(m_optionalChainTargetStack.takeLast().get());
}
void BytecodeGenerator::popOptionalChainTarget(RegisterID* dst, bool isDelete)
{
Ref<Label> endLabel = newLabel();
emitJump(endLabel.get());
popOptionalChainTarget();
emitLoad(dst, isDelete ? jsBoolean(true) : jsUndefined());
emitLabel(endLabel.get());
}
void BytecodeGenerator::emitOptionalCheck(RegisterID* src)
{
ASSERT(m_optionalChainTargetStack.size());
emitJumpIfTrue(emitIsUndefinedOrNull(newTemporary(), src), m_optionalChainTargetStack.last().get());
}
void ForInContext::finalize(BytecodeGenerator& generator, UnlinkedCodeBlock* codeBlock, unsigned bodyBytecodeEndOffset)
{
// Lexically invalidating ForInContexts is kind of weak sauce, but it only occurs if
// either of the following conditions is true:
//
// (1) The loop iteration variable is re-assigned within the body of the loop.
// (2) The loop iteration variable is captured in the lexical scope of the function.
//
// These two situations occur sufficiently rarely that it's okay to use this style of
// "analysis" to make iteration faster. If we didn't want to do this, we would either have
// to perform some flow-sensitive analysis to see if/when the loop iteration variable was
// reassigned, or we'd have to resort to runtime checks to see if the variable had been
// reassigned from its original value.
for (unsigned offset = bodyBytecodeStartOffset(); isValid() && offset < bodyBytecodeEndOffset;) {
auto instruction = generator.instructions().at(offset);
ASSERT(!instruction->is<OpEnter>());
computeDefsForBytecodeIndex(codeBlock, instruction.ptr(), [&] (VirtualRegister operand) {
if (local()->virtualRegister() == operand)
invalidate();
});
offset += instruction->size();
}
}
void StructureForInContext::finalize(BytecodeGenerator& generator, UnlinkedCodeBlock* codeBlock, unsigned bodyBytecodeEndOffset)
{
Base::finalize(generator, codeBlock, bodyBytecodeEndOffset);
if (isValid())
return;
OpcodeID lastOpcodeID = generator.m_lastOpcodeID;
InstructionStream::MutableRef lastInstruction = generator.m_lastInstruction;
for (const auto& instTuple : m_getInsts) {
unsigned instIndex = std::get<0>(instTuple);
int propertyRegIndex = std::get<1>(instTuple);
auto instruction = generator.m_writer.ref(instIndex);
auto end = instIndex + instruction->size();
ASSERT(instruction->isWide32());
generator.m_writer.seek(instIndex);
auto bytecode = instruction->as<OpGetDirectPname>();
// disable peephole optimizations
generator.m_lastOpcodeID = op_end;
// Change the opcode to get_by_val.
// 1. dst stays the same.
// 2. base stays the same.
// 3. property gets switched to the original property.
OpGetByVal::emit<OpcodeSize::Wide32>(&generator, bytecode.m_dst, bytecode.m_base, VirtualRegister(propertyRegIndex));
// 4. nop out the remaining bytes
while (generator.m_writer.position() < end)
OpNop::emit<OpcodeSize::Narrow>(&generator);
}
generator.m_writer.seek(generator.m_writer.size());
if (generator.m_lastInstruction.offset() + generator.m_lastInstruction->size() != generator.m_writer.size()) {
generator.m_lastOpcodeID = lastOpcodeID;
generator.m_lastInstruction = lastInstruction;
}
}
void IndexedForInContext::finalize(BytecodeGenerator& generator, UnlinkedCodeBlock* codeBlock, unsigned bodyBytecodeEndOffset)
{
Base::finalize(generator, codeBlock, bodyBytecodeEndOffset);
if (isValid())
return;
for (const auto& instPair : m_getInsts) {
unsigned instIndex = instPair.first;
int propertyRegIndex = instPair.second;
generator.m_writer.ref(instIndex)->cast<OpGetByVal>()->setProperty(VirtualRegister(propertyRegIndex), []() {
ASSERT_NOT_REACHED();
return VirtualRegister();
});
}
}
void StaticPropertyAnalysis::record()
{
auto* instruction = m_instructionRef.ptr();
auto size = m_propertyIndexes.size();
switch (instruction->opcodeID()) {
case OpNewObject::opcodeID:
instruction->cast<OpNewObject>()->setInlineCapacity(size, []() {
return 255;
});
return;
case OpCreateThis::opcodeID:
instruction->cast<OpCreateThis>()->setInlineCapacity(size, []() {
return 255;
});
return;
default:
ASSERT_NOT_REACHED();
}
}
void BytecodeGenerator::emitToThis()
{
OpToThis::emit(this, kill(&m_thisRegister));
}
} // namespace JSC
namespace WTF {
void printInternal(PrintStream& out, JSC::Variable::VariableKind kind)
{
switch (kind) {
case JSC::Variable::NormalVariable:
out.print("Normal");
return;
case JSC::Variable::SpecialVariable:
out.print("Special");
return;
}
RELEASE_ASSERT_NOT_REACHED();
}
} // namespace WTF