#include "config.h"
#include "JSScope.h"
#include "JSGlobalObject.h"
#include "JSLexicalEnvironment.h"
#include "JSModuleEnvironment.h"
#include "JSModuleRecord.h"
#include "JSWithScope.h"
#include "JSCInlines.h"
#include "VariableEnvironment.h"
namespace JSC {
STATIC_ASSERT_IS_TRIVIALLY_DESTRUCTIBLE(JSScope);
void JSScope::visitChildren(JSCell* cell, SlotVisitor& visitor)
{
JSScope* thisObject = jsCast<JSScope*>(cell);
ASSERT_GC_OBJECT_INHERITS(thisObject, info());
Base::visitChildren(thisObject, visitor);
visitor.append(&thisObject->m_next);
}
static inline bool abstractAccess(ExecState* exec, JSScope* scope, const Identifier& ident, GetOrPut getOrPut, size_t depth, bool& needsVarInjectionChecks, ResolveOp& op, InitializationMode initializationMode)
{
if (scope->isJSLexicalEnvironment()) {
JSLexicalEnvironment* lexicalEnvironment = jsCast<JSLexicalEnvironment*>(scope);
if (ident == exec->propertyNames().arguments) {
op = ResolveOp(Dynamic, 0, 0, 0, 0, 0);
return true;
}
SymbolTable* symbolTable = lexicalEnvironment->symbolTable();
{
ConcurrentJITLocker locker(symbolTable->m_lock);
auto iter = symbolTable->find(locker, ident.impl());
if (iter != symbolTable->end(locker)) {
SymbolTableEntry& entry = iter->value;
ASSERT(!entry.isNull());
if (entry.isReadOnly() && getOrPut == Put) {
op = ResolveOp(Dynamic, 0, 0, 0, 0, 0);
return true;
}
op = ResolveOp(makeType(ClosureVar, needsVarInjectionChecks), depth, 0, lexicalEnvironment, entry.watchpointSet(), entry.scopeOffset().offset());
return true;
}
}
if (scope->type() == ModuleEnvironmentType) {
JSModuleEnvironment* moduleEnvironment = jsCast<JSModuleEnvironment*>(scope);
JSModuleRecord* moduleRecord = moduleEnvironment->moduleRecord();
JSModuleRecord::Resolution resolution = moduleRecord->resolveImport(exec, ident);
if (resolution.type == JSModuleRecord::Resolution::Type::Resolved) {
JSModuleRecord* importedRecord = resolution.moduleRecord;
JSModuleEnvironment* importedEnvironment = importedRecord->moduleEnvironment();
SymbolTable* symbolTable = importedEnvironment->symbolTable();
ConcurrentJITLocker locker(symbolTable->m_lock);
auto iter = symbolTable->find(locker, resolution.localName.impl());
ASSERT(iter != symbolTable->end(locker));
SymbolTableEntry& entry = iter->value;
ASSERT(!entry.isNull());
op = ResolveOp(makeType(ModuleVar, needsVarInjectionChecks), depth, 0, importedEnvironment, entry.watchpointSet(), entry.scopeOffset().offset(), resolution.localName.impl());
return true;
}
}
if (symbolTable->usesNonStrictEval())
needsVarInjectionChecks = true;
return false;
}
if (scope->isGlobalLexicalEnvironment()) {
JSGlobalLexicalEnvironment* globalLexicalEnvironment = jsCast<JSGlobalLexicalEnvironment*>(scope);
SymbolTable* symbolTable = globalLexicalEnvironment->symbolTable();
ConcurrentJITLocker locker(symbolTable->m_lock);
auto iter = symbolTable->find(locker, ident.impl());
if (iter != symbolTable->end(locker)) {
SymbolTableEntry& entry = iter->value;
ASSERT(!entry.isNull());
if (getOrPut == Put && entry.isReadOnly() && !isInitialization(initializationMode)) {
op = ResolveOp(Dynamic, 0, 0, 0, 0, 0);
return true;
}
ResolveType resolveType = initializationMode == InitializationMode::ConstInitialization ? GlobalLexicalVar : makeType(GlobalLexicalVar, needsVarInjectionChecks);
op = ResolveOp(
resolveType, depth, 0, 0, entry.watchpointSet(),
reinterpret_cast<uintptr_t>(globalLexicalEnvironment->variableAt(entry.scopeOffset()).slot()));
return true;
}
return false;
}
if (scope->isGlobalObject()) {
JSGlobalObject* globalObject = jsCast<JSGlobalObject*>(scope);
{
SymbolTable* symbolTable = globalObject->symbolTable();
ConcurrentJITLocker locker(symbolTable->m_lock);
auto iter = symbolTable->find(locker, ident.impl());
if (iter != symbolTable->end(locker)) {
SymbolTableEntry& entry = iter->value;
ASSERT(!entry.isNull());
if (getOrPut == Put && entry.isReadOnly()) {
op = ResolveOp(Dynamic, 0, 0, 0, 0, 0);
return true;
}
op = ResolveOp(
makeType(GlobalVar, needsVarInjectionChecks), depth, 0, 0, entry.watchpointSet(),
reinterpret_cast<uintptr_t>(globalObject->variableAt(entry.scopeOffset()).slot()));
return true;
}
}
PropertySlot slot(globalObject, PropertySlot::InternalMethodType::VMInquiry);
bool hasOwnProperty = globalObject->getOwnPropertySlot(globalObject, exec, ident, slot);
if (!hasOwnProperty) {
op = ResolveOp(makeType(UnresolvedProperty, needsVarInjectionChecks), 0, 0, 0, 0, 0);
return true;
}
if (!slot.isCacheableValue()
|| !globalObject->structure()->propertyAccessesAreCacheable()
|| (globalObject->structure()->hasReadOnlyOrGetterSetterPropertiesExcludingProto() && getOrPut == Put)) {
ASSERT(!scope->next());
op = ResolveOp(makeType(GlobalProperty, needsVarInjectionChecks), 0, 0, 0, 0, 0);
return true;
}
WatchpointState state = globalObject->structure()->ensurePropertyReplacementWatchpointSet(exec->vm(), slot.cachedOffset())->state();
if (state == IsWatched && getOrPut == Put) {
op = ResolveOp(makeType(GlobalProperty, needsVarInjectionChecks), depth, 0, 0, 0, 0);
} else
op = ResolveOp(makeType(GlobalProperty, needsVarInjectionChecks), depth, globalObject->structure(), 0, 0, slot.cachedOffset());
return true;
}
op = ResolveOp(Dynamic, 0, 0, 0, 0, 0);
return true;
}
JSObject* JSScope::objectAtScope(JSScope* scope)
{
JSObject* object = scope;
if (object->type() == WithScopeType)
return jsCast<JSWithScope*>(object)->object();
return object;
}
static inline bool isUnscopable(ExecState* exec, JSScope* scope, JSObject* object, const Identifier& ident)
{
if (scope->type() != WithScopeType)
return false;
JSValue unscopables = object->get(exec, exec->propertyNames().unscopablesSymbol);
if (exec->hadException())
return false;
if (!unscopables.isObject())
return false;
JSValue blocked = jsCast<JSObject*>(unscopables)->get(exec, ident);
if (exec->hadException())
return false;
return blocked.toBoolean(exec);
}
JSObject* JSScope::resolve(ExecState* exec, JSScope* scope, const Identifier& ident)
{
ScopeChainIterator end = scope->end();
ScopeChainIterator it = scope->begin();
while (1) {
JSScope* scope = it.scope();
JSObject* object = it.get();
if (++it == end) {
JSScope* globalScopeExtension = scope->globalObject()->globalScopeExtension();
if (UNLIKELY(globalScopeExtension)) {
if (object->hasProperty(exec, ident))
return object;
JSObject* extensionScopeObject = JSScope::objectAtScope(globalScopeExtension);
if (extensionScopeObject->hasProperty(exec, ident))
return extensionScopeObject;
}
return object;
}
if (object->hasProperty(exec, ident)) {
if (!isUnscopable(exec, scope, object, ident))
return object;
ASSERT_WITH_MESSAGE(!exec->hadException(), "When an exception occurs, the result of isUnscopable becomes false");
}
}
}
ResolveOp JSScope::abstractResolve(ExecState* exec, size_t depthOffset, JSScope* scope, const Identifier& ident, GetOrPut getOrPut, ResolveType unlinkedType, InitializationMode initializationMode)
{
ResolveOp op(Dynamic, 0, 0, 0, 0, 0);
if (unlinkedType == Dynamic)
return op;
bool needsVarInjectionChecks = JSC::needsVarInjectionChecks(unlinkedType);
size_t depth = depthOffset;
for (; scope; scope = scope->next()) {
if (abstractAccess(exec, scope, ident, getOrPut, depth, needsVarInjectionChecks, op, initializationMode))
break;
++depth;
}
return op;
}
void JSScope::collectVariablesUnderTDZ(JSScope* scope, VariableEnvironment& result)
{
for (; scope; scope = scope->next()) {
if (!scope->isLexicalScope() && !scope->isGlobalLexicalEnvironment())
continue;
if (scope->isModuleScope()) {
JSModuleRecord* moduleRecord = jsCast<JSModuleEnvironment*>(scope)->moduleRecord();
for (const auto& pair : moduleRecord->importEntries())
result.add(pair.key);
}
SymbolTable* symbolTable = jsCast<JSSymbolTableObject*>(scope)->symbolTable();
ASSERT(symbolTable->scopeType() == SymbolTable::ScopeType::LexicalScope || symbolTable->scopeType() == SymbolTable::ScopeType::GlobalLexicalScope);
ConcurrentJITLocker locker(symbolTable->m_lock);
for (auto end = symbolTable->end(locker), iter = symbolTable->begin(locker); iter != end; ++iter)
result.add(iter->key);
}
}
bool JSScope::isVarScope()
{
if (type() != LexicalEnvironmentType)
return false;
return jsCast<JSLexicalEnvironment*>(this)->symbolTable()->scopeType() == SymbolTable::ScopeType::VarScope;
}
bool JSScope::isLexicalScope()
{
if (!isJSLexicalEnvironment())
return false;
return jsCast<JSLexicalEnvironment*>(this)->symbolTable()->scopeType() == SymbolTable::ScopeType::LexicalScope;
}
bool JSScope::isModuleScope()
{
return type() == ModuleEnvironmentType;
}
bool JSScope::isCatchScope()
{
if (type() != LexicalEnvironmentType)
return false;
return jsCast<JSLexicalEnvironment*>(this)->symbolTable()->scopeType() == SymbolTable::ScopeType::CatchScope;
}
bool JSScope::isFunctionNameScopeObject()
{
if (type() != LexicalEnvironmentType)
return false;
return jsCast<JSLexicalEnvironment*>(this)->symbolTable()->scopeType() == SymbolTable::ScopeType::FunctionNameScope;
}
bool JSScope::isNestedLexicalScope()
{
if (!isJSLexicalEnvironment())
return false;
return jsCast<JSLexicalEnvironment*>(this)->symbolTable()->isNestedLexicalScope();
}
JSScope* JSScope::constantScopeForCodeBlock(ResolveType type, CodeBlock* codeBlock)
{
switch (type) {
case GlobalProperty:
case GlobalVar:
case GlobalPropertyWithVarInjectionChecks:
case GlobalVarWithVarInjectionChecks:
return codeBlock->globalObject();
case GlobalLexicalVarWithVarInjectionChecks:
case GlobalLexicalVar:
return codeBlock->globalObject()->globalLexicalEnvironment();
default:
return nullptr;
}
RELEASE_ASSERT_NOT_REACHED();
return nullptr;
}
SymbolTable* JSScope::symbolTable()
{
if (JSSymbolTableObject* symbolTableObject = jsDynamicCast<JSSymbolTableObject*>(this))
return symbolTableObject->symbolTable();
return nullptr;
}
}