Source/JavaScriptCore/runtime/SymbolTable.cpp - WebKit - Git at Google

 /*
  * Copyright (C) 2012-2019 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
  *     notice, this list of conditions and the following disclaimer in the
  *     documentation and/or other materials provided with the distribution.
  * 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 "SymbolTable.h"

 #include "CodeBlock.h"
 #include "JSDestructibleObject.h"
 #include "JSCInlines.h"
 #include "SlotVisitorInlines.h"
 #include "TypeProfiler.h"

 namespace JSC {

 const ClassInfo SymbolTable::s_info = { "SymbolTable", nullptr, nullptr, nullptr, CREATE_METHOD_TABLE(SymbolTable) };

 DEFINE_ALLOCATOR_WITH_HEAP_IDENTIFIER(SymbolTableEntryFatEntry);

 SymbolTableEntry& SymbolTableEntry::copySlow(const SymbolTableEntry& other)
 {
     ASSERT(other.isFat());
     FatEntry* newFatEntry = new FatEntry(*other.fatEntry());
     freeFatEntry();
     m_bits = bitwise_cast<intptr_t>(newFatEntry);
     return *this;
 }

 void SymbolTable::destroy(JSCell* cell)
 {
     SymbolTable* thisObject = static_cast<SymbolTable*>(cell);
     thisObject->SymbolTable::~SymbolTable();
 }

 void SymbolTableEntry::freeFatEntrySlow()
 {
     ASSERT(isFat());
     delete fatEntry();
 }

 void SymbolTableEntry::prepareToWatch()
 {
     if (!isWatchable())
         return;
     FatEntry* entry = inflate();
     if (entry->m_watchpoints)
         return;
     entry->m_watchpoints = adoptRef(new WatchpointSet(ClearWatchpoint));
 }

 SymbolTableEntry::FatEntry* SymbolTableEntry::inflateSlow()
 {
     FatEntry* entry = new FatEntry(m_bits);
     m_bits = bitwise_cast<intptr_t>(entry);
     return entry;
 }

 SymbolTable::SymbolTable(VM& vm)
     : JSCell(vm, vm.symbolTableStructure.get())
     , m_usesNonStrictEval(false)
     , m_nestedLexicalScope(false)
     , m_scopeType(VarScope)
 {
 }

 SymbolTable::~SymbolTable() { }

 void SymbolTable::finishCreation(VM& vm)
 {
     Base::finishCreation(vm);
 }

 void SymbolTable::visitChildren(JSCell* thisCell, SlotVisitor& visitor)
 {
     SymbolTable* thisSymbolTable = jsCast<SymbolTable*>(thisCell);
     ASSERT_GC_OBJECT_INHERITS(thisSymbolTable, info());
     Base::visitChildren(thisSymbolTable, visitor);

     visitor.append(thisSymbolTable->m_arguments);

     if (thisSymbolTable->m_rareData)
         visitor.append(thisSymbolTable->m_rareData->m_codeBlock);

     // Save some memory. This is O(n) to rebuild and we do so on the fly.
     ConcurrentJSLocker locker(thisSymbolTable->m_lock);
     thisSymbolTable->m_localToEntry = nullptr;
 }

 const SymbolTable::LocalToEntryVec& SymbolTable::localToEntry(const ConcurrentJSLocker&)
 {
     if (UNLIKELY(!m_localToEntry)) {
         unsigned size = 0;
         for (auto& entry : m_map) {
             VarOffset offset = entry.value.varOffset();
             if (offset.isScope())
                 size = std::max(size, offset.scopeOffset().offset() + 1);
         }

         m_localToEntry = makeUnique<LocalToEntryVec>(size, nullptr);
         for (auto& entry : m_map) {
             VarOffset offset = entry.value.varOffset();
             if (offset.isScope())
                 m_localToEntry->at(offset.scopeOffset().offset()) = &entry.value;
         }
     }

     return *m_localToEntry;
 }

 SymbolTableEntry* SymbolTable::entryFor(const ConcurrentJSLocker& locker, ScopeOffset offset)
 {
     auto& toEntryVector = localToEntry(locker);
     if (offset.offset() >= toEntryVector.size())
         return nullptr;
     return toEntryVector[offset.offset()];
 }

 SymbolTable* SymbolTable::cloneScopePart(VM& vm)
 {
     SymbolTable* result = SymbolTable::create(vm);

     result->m_usesNonStrictEval = m_usesNonStrictEval;
     result->m_nestedLexicalScope = m_nestedLexicalScope;
     result->m_scopeType = m_scopeType;

     for (auto iter = m_map.begin(), end = m_map.end(); iter != end; ++iter) {
         if (!iter->value.varOffset().isScope())
             continue;
         result->m_map.add(
             iter->key,
             SymbolTableEntry(iter->value.varOffset(), iter->value.getAttributes()));
     }

     result->m_maxScopeOffset = m_maxScopeOffset;

     if (ScopedArgumentsTable* arguments = this->arguments())
         result->m_arguments.set(vm, result, arguments);

     if (m_rareData) {
         result->m_rareData = makeUnique<SymbolTableRareData>();

         {
             auto iter = m_rareData->m_uniqueIDMap.begin();
             auto end = m_rareData->m_uniqueIDMap.end();
             for (; iter != end; ++iter)
                 result->m_rareData->m_uniqueIDMap.set(iter->key, iter->value);
         }

         {
             auto iter = m_rareData->m_offsetToVariableMap.begin();
             auto end = m_rareData->m_offsetToVariableMap.end();
             for (; iter != end; ++iter)
                 result->m_rareData->m_offsetToVariableMap.set(iter->key, iter->value);
         }

         {
             auto iter = m_rareData->m_uniqueTypeSetMap.begin();
             auto end = m_rareData->m_uniqueTypeSetMap.end();
             for (; iter != end; ++iter)
                 result->m_rareData->m_uniqueTypeSetMap.set(iter->key, iter->value);
         }
     }

     return result;
 }

 void SymbolTable::prepareForTypeProfiling(const ConcurrentJSLocker&)
 {
     if (m_rareData)
         return;

     m_rareData = makeUnique<SymbolTableRareData>();

     for (auto iter = m_map.begin(), end = m_map.end(); iter != end; ++iter) {
         m_rareData->m_uniqueIDMap.set(iter->key, TypeProfilerNeedsUniqueIDGeneration);
         m_rareData->m_offsetToVariableMap.set(iter->value.varOffset(), iter->key);
     }
 }

 CodeBlock* SymbolTable::rareDataCodeBlock()
 {
     if (!m_rareData)
         return nullptr;

     return m_rareData->m_codeBlock.get();
 }

 void SymbolTable::setRareDataCodeBlock(CodeBlock* codeBlock)
 {
     if (!m_rareData)
         m_rareData = makeUnique<SymbolTableRareData>();

     ASSERT(!m_rareData->m_codeBlock);
     m_rareData->m_codeBlock.set(codeBlock->vm(), this, codeBlock);
 }

 GlobalVariableID SymbolTable::uniqueIDForVariable(const ConcurrentJSLocker&, UniquedStringImpl* key, VM& vm)
 {
     RELEASE_ASSERT(m_rareData);

     auto iter = m_rareData->m_uniqueIDMap.find(key);
     auto end = m_rareData->m_uniqueIDMap.end();
     if (iter == end)
         return TypeProfilerNoGlobalIDExists;

     GlobalVariableID id = iter->value;
     if (id == TypeProfilerNeedsUniqueIDGeneration) {
         id = vm.typeProfiler()->getNextUniqueVariableID();
         m_rareData->m_uniqueIDMap.set(key, id);
         m_rareData->m_uniqueTypeSetMap.set(key, TypeSet::create()); // Make a new global typeset for this corresponding ID.
     }

     return id;
 }

 GlobalVariableID SymbolTable::uniqueIDForOffset(const ConcurrentJSLocker& locker, VarOffset offset, VM& vm)
 {
     RELEASE_ASSERT(m_rareData);

     auto iter = m_rareData->m_offsetToVariableMap.find(offset);
     auto end = m_rareData->m_offsetToVariableMap.end();
     if (iter == end)
         return TypeProfilerNoGlobalIDExists;

     return uniqueIDForVariable(locker, iter->value.get(), vm);
 }

 RefPtr<TypeSet> SymbolTable::globalTypeSetForOffset(const ConcurrentJSLocker& locker, VarOffset offset, VM& vm)
 {
     RELEASE_ASSERT(m_rareData);

     uniqueIDForOffset(locker, offset, vm); // Lazily create the TypeSet if necessary.

     auto iter = m_rareData->m_offsetToVariableMap.find(offset);
     auto end = m_rareData->m_offsetToVariableMap.end();
     if (iter == end)
         return nullptr;

     return globalTypeSetForVariable(locker, iter->value.get(), vm);
 }

 RefPtr<TypeSet> SymbolTable::globalTypeSetForVariable(const ConcurrentJSLocker& locker, UniquedStringImpl* key, VM& vm)
 {
     RELEASE_ASSERT(m_rareData);

     uniqueIDForVariable(locker, key, vm); // Lazily create the TypeSet if necessary.

     auto iter = m_rareData->m_uniqueTypeSetMap.find(key);
     auto end = m_rareData->m_uniqueTypeSetMap.end();
     if (iter == end)
         return nullptr;

     return iter->value;
 }

 } // namespace JSC
	/*
	* Copyright (C) 2012-2019 Apple Inc. All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	*
	* 1. Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* 2. Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in the
	* documentation and/or other materials provided with the distribution.
	* 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 "SymbolTable.h"

	#include "CodeBlock.h"
	#include "JSDestructibleObject.h"
	#include "JSCInlines.h"
	#include "SlotVisitorInlines.h"
	#include "TypeProfiler.h"

	namespace JSC {

	const ClassInfo SymbolTable::s_info = { "SymbolTable", nullptr, nullptr, nullptr, CREATE_METHOD_TABLE(SymbolTable) };

	DEFINE_ALLOCATOR_WITH_HEAP_IDENTIFIER(SymbolTableEntryFatEntry);

	SymbolTableEntry& SymbolTableEntry::copySlow(const SymbolTableEntry& other)
	{
	ASSERT(other.isFat());
	FatEntry* newFatEntry = new FatEntry(*other.fatEntry());
	freeFatEntry();
	m_bits = bitwise_cast<intptr_t>(newFatEntry);
	return *this;
	}

	void SymbolTable::destroy(JSCell* cell)
	{
	SymbolTable* thisObject = static_cast<SymbolTable*>(cell);
	thisObject->SymbolTable::~SymbolTable();
	}

	void SymbolTableEntry::freeFatEntrySlow()
	{
	ASSERT(isFat());
	delete fatEntry();
	}

	void SymbolTableEntry::prepareToWatch()
	{
	if (!isWatchable())
	return;
	FatEntry* entry = inflate();
	if (entry->m_watchpoints)
	return;
	entry->m_watchpoints = adoptRef(new WatchpointSet(ClearWatchpoint));
	}

	SymbolTableEntry::FatEntry* SymbolTableEntry::inflateSlow()
	{
	FatEntry* entry = new FatEntry(m_bits);
	m_bits = bitwise_cast<intptr_t>(entry);
	return entry;
	}

	SymbolTable::SymbolTable(VM& vm)
	: JSCell(vm, vm.symbolTableStructure.get())
	, m_usesNonStrictEval(false)
	, m_nestedLexicalScope(false)
	, m_scopeType(VarScope)
	{
	}

	SymbolTable::~SymbolTable() { }

	void SymbolTable::finishCreation(VM& vm)
	{
	Base::finishCreation(vm);
	}

	void SymbolTable::visitChildren(JSCell* thisCell, SlotVisitor& visitor)
	{
	SymbolTable* thisSymbolTable = jsCast<SymbolTable*>(thisCell);
	ASSERT_GC_OBJECT_INHERITS(thisSymbolTable, info());
	Base::visitChildren(thisSymbolTable, visitor);

	visitor.append(thisSymbolTable->m_arguments);

	if (thisSymbolTable->m_rareData)
	visitor.append(thisSymbolTable->m_rareData->m_codeBlock);

	// Save some memory. This is O(n) to rebuild and we do so on the fly.
	ConcurrentJSLocker locker(thisSymbolTable->m_lock);
	thisSymbolTable->m_localToEntry = nullptr;
	}

	const SymbolTable::LocalToEntryVec& SymbolTable::localToEntry(const ConcurrentJSLocker&)
	{
	if (UNLIKELY(!m_localToEntry)) {
	unsigned size = 0;
	for (auto& entry : m_map) {
	VarOffset offset = entry.value.varOffset();
	if (offset.isScope())
	size = std::max(size, offset.scopeOffset().offset() + 1);
	}

	m_localToEntry = makeUnique<LocalToEntryVec>(size, nullptr);
	for (auto& entry : m_map) {
	VarOffset offset = entry.value.varOffset();
	if (offset.isScope())
	m_localToEntry->at(offset.scopeOffset().offset()) = &entry.value;
	}
	}

	return *m_localToEntry;
	}

	SymbolTableEntry* SymbolTable::entryFor(const ConcurrentJSLocker& locker, ScopeOffset offset)
	{
	auto& toEntryVector = localToEntry(locker);
	if (offset.offset() >= toEntryVector.size())
	return nullptr;
	return toEntryVector[offset.offset()];
	}

	SymbolTable* SymbolTable::cloneScopePart(VM& vm)
	{
	SymbolTable* result = SymbolTable::create(vm);

	result->m_usesNonStrictEval = m_usesNonStrictEval;
	result->m_nestedLexicalScope = m_nestedLexicalScope;
	result->m_scopeType = m_scopeType;

	for (auto iter = m_map.begin(), end = m_map.end(); iter != end; ++iter) {
	if (!iter->value.varOffset().isScope())
	continue;
	result->m_map.add(
	iter->key,
	SymbolTableEntry(iter->value.varOffset(), iter->value.getAttributes()));
	}

	result->m_maxScopeOffset = m_maxScopeOffset;

	if (ScopedArgumentsTable* arguments = this->arguments())
	result->m_arguments.set(vm, result, arguments);

	if (m_rareData) {
	result->m_rareData = makeUnique<SymbolTableRareData>();

	{
	auto iter = m_rareData->m_uniqueIDMap.begin();
	auto end = m_rareData->m_uniqueIDMap.end();
	for (; iter != end; ++iter)
	result->m_rareData->m_uniqueIDMap.set(iter->key, iter->value);
	}

	{
	auto iter = m_rareData->m_offsetToVariableMap.begin();
	auto end = m_rareData->m_offsetToVariableMap.end();
	for (; iter != end; ++iter)
	result->m_rareData->m_offsetToVariableMap.set(iter->key, iter->value);
	}

	{
	auto iter = m_rareData->m_uniqueTypeSetMap.begin();
	auto end = m_rareData->m_uniqueTypeSetMap.end();
	for (; iter != end; ++iter)
	result->m_rareData->m_uniqueTypeSetMap.set(iter->key, iter->value);
	}
	}

	return result;
	}

	void SymbolTable::prepareForTypeProfiling(const ConcurrentJSLocker&)
	{
	if (m_rareData)
	return;

	m_rareData = makeUnique<SymbolTableRareData>();

	for (auto iter = m_map.begin(), end = m_map.end(); iter != end; ++iter) {
	m_rareData->m_uniqueIDMap.set(iter->key, TypeProfilerNeedsUniqueIDGeneration);
	m_rareData->m_offsetToVariableMap.set(iter->value.varOffset(), iter->key);
	}
	}

	CodeBlock* SymbolTable::rareDataCodeBlock()
	{
	if (!m_rareData)
	return nullptr;

	return m_rareData->m_codeBlock.get();
	}

	void SymbolTable::setRareDataCodeBlock(CodeBlock* codeBlock)
	{
	if (!m_rareData)
	m_rareData = makeUnique<SymbolTableRareData>();

	ASSERT(!m_rareData->m_codeBlock);
	m_rareData->m_codeBlock.set(codeBlock->vm(), this, codeBlock);
	}

	GlobalVariableID SymbolTable::uniqueIDForVariable(const ConcurrentJSLocker&, UniquedStringImpl* key, VM& vm)
	{
	RELEASE_ASSERT(m_rareData);

	auto iter = m_rareData->m_uniqueIDMap.find(key);
	auto end = m_rareData->m_uniqueIDMap.end();
	if (iter == end)
	return TypeProfilerNoGlobalIDExists;

	GlobalVariableID id = iter->value;
	if (id == TypeProfilerNeedsUniqueIDGeneration) {
	id = vm.typeProfiler()->getNextUniqueVariableID();
	m_rareData->m_uniqueIDMap.set(key, id);
	m_rareData->m_uniqueTypeSetMap.set(key, TypeSet::create()); // Make a new global typeset for this corresponding ID.
	}

	return id;
	}

	GlobalVariableID SymbolTable::uniqueIDForOffset(const ConcurrentJSLocker& locker, VarOffset offset, VM& vm)
	{
	RELEASE_ASSERT(m_rareData);

	auto iter = m_rareData->m_offsetToVariableMap.find(offset);
	auto end = m_rareData->m_offsetToVariableMap.end();
	if (iter == end)
	return TypeProfilerNoGlobalIDExists;

	return uniqueIDForVariable(locker, iter->value.get(), vm);
	}

	RefPtr<TypeSet> SymbolTable::globalTypeSetForOffset(const ConcurrentJSLocker& locker, VarOffset offset, VM& vm)
	{
	RELEASE_ASSERT(m_rareData);

	uniqueIDForOffset(locker, offset, vm); // Lazily create the TypeSet if necessary.

	auto iter = m_rareData->m_offsetToVariableMap.find(offset);
	auto end = m_rareData->m_offsetToVariableMap.end();
	if (iter == end)
	return nullptr;

	return globalTypeSetForVariable(locker, iter->value.get(), vm);
	}

	RefPtr<TypeSet> SymbolTable::globalTypeSetForVariable(const ConcurrentJSLocker& locker, UniquedStringImpl* key, VM& vm)
	{
	RELEASE_ASSERT(m_rareData);

	uniqueIDForVariable(locker, key, vm); // Lazily create the TypeSet if necessary.

	auto iter = m_rareData->m_uniqueTypeSetMap.find(key);
	auto end = m_rareData->m_uniqueTypeSetMap.end();
	if (iter == end)
	return nullptr;

	return iter->value;
	}

	} // namespace JSC