Source/JavaScriptCore/dfg/DFGLazyJSValue.cpp - WebKit - Git at Google

 /*
  * Copyright (C) 2013, 2014, 2016 Apple Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */

 #include "config.h"
 #include "DFGLazyJSValue.h"

 #if ENABLE(DFG_JIT)

 #include "CCallHelpers.h"
 #include "DFGGraph.h"
 #include "JSCInlines.h"
 #include "LinkBuffer.h"

 namespace JSC { namespace DFG {

 LazyJSValue LazyJSValue::newString(Graph& graph, const String& string)
 {
     LazyJSValue result;
     result.m_kind = NewStringImpl;
     result.u.stringImpl = graph.m_localStrings.add(string).iterator->impl();
     return result;
 }

 JSValue LazyJSValue::getValue(VM& vm) const
 {
     switch (m_kind) {
     case KnownValue:
         return value()->value();
     case SingleCharacterString:
         return jsSingleCharacterString(&vm, u.character);
     case KnownStringImpl:
         return jsString(&vm, u.stringImpl);
     case NewStringImpl:
         return jsString(&vm, AtomicStringImpl::add(u.stringImpl));
     }
     RELEASE_ASSERT_NOT_REACHED();
     return JSValue();
 }

 static TriState equalToSingleCharacter(JSValue value, UChar character)
 {
     if (!value.isString())
         return FalseTriState;

     JSString* jsString = asString(value);
     if (jsString->length() != 1)
         return FalseTriState;

     const StringImpl* string = jsString->tryGetValueImpl();
     if (!string)
         return MixedTriState;

     return triState(string->at(0) == character);
 }

 static TriState equalToStringImpl(JSValue value, StringImpl* stringImpl)
 {
     if (!value.isString())
         return FalseTriState;

     JSString* jsString = asString(value);
     const StringImpl* string = jsString->tryGetValueImpl();
     if (!string)
         return MixedTriState;

     return triState(WTF::equal(stringImpl, string));
 }

 const StringImpl* LazyJSValue::tryGetStringImpl(VM& vm) const
 {
     switch (m_kind) {
     case KnownStringImpl:
     case NewStringImpl:
         return u.stringImpl;

     case KnownValue:
         if (JSString* string = value()->dynamicCast<JSString*>(vm))
             return string->tryGetValueImpl();
         return nullptr;

     default:
         return nullptr;
     }
 }

 String LazyJSValue::tryGetString(Graph& graph) const
 {
     switch (m_kind) {
     case NewStringImpl:
         return u.stringImpl;

     case SingleCharacterString:
         return String(&u.character, 1);

     default:
         if (const StringImpl* string = tryGetStringImpl(graph.m_vm)) {
             unsigned ginormousStringLength = 10000;
             if (string->length() > ginormousStringLength)
                 return String();

             auto result = graph.m_copiedStrings.add(string, String());
             if (result.isNewEntry)
                 result.iterator->value = string->isolatedCopy();
             return result.iterator->value;
         }

         return String();
     }
 }

 TriState LazyJSValue::strictEqual(const LazyJSValue& other) const
 {
     switch (m_kind) {
     case KnownValue:
         switch (other.m_kind) {
         case KnownValue:
             return JSValue::pureStrictEqual(value()->value(), other.value()->value());
         case SingleCharacterString:
             return equalToSingleCharacter(value()->value(), other.character());
         case KnownStringImpl:
         case NewStringImpl:
             return equalToStringImpl(value()->value(), other.stringImpl());
         }
         break;
     case SingleCharacterString:
         switch (other.m_kind) {
         case SingleCharacterString:
             return triState(character() == other.character());
         case KnownStringImpl:
         case NewStringImpl:
             if (other.stringImpl()->length() != 1)
                 return FalseTriState;
             return triState(other.stringImpl()->at(0) == character());
         default:
             return other.strictEqual(*this);
         }
         break;
     case KnownStringImpl:
     case NewStringImpl:
         switch (other.m_kind) {
         case KnownStringImpl:
         case NewStringImpl:
             return triState(WTF::equal(stringImpl(), other.stringImpl()));
         default:
             return other.strictEqual(*this);
         }
         break;
     }
     RELEASE_ASSERT_NOT_REACHED();
     return FalseTriState;
 }

 uintptr_t LazyJSValue::switchLookupValue(SwitchKind kind) const
 {
     // NB. Not every kind of JSValue will be able to give you a switch lookup
     // value, and this method will assert, or do bad things, if you use it
     // for a kind of value that can't.
     switch (m_kind) {
     case KnownValue:
         switch (kind) {
         case SwitchImm:
             return value()->value().asInt32();
         case SwitchCell:
             return bitwise_cast<uintptr_t>(value()->value().asCell());
         default:
             RELEASE_ASSERT_NOT_REACHED();
             return 0;
         }
     case SingleCharacterString:
         switch (kind) {
         case SwitchChar:
             return character();
         default:
             RELEASE_ASSERT_NOT_REACHED();
             return 0;
         }
     default:
         RELEASE_ASSERT_NOT_REACHED();
         return 0;
     }
 }

 void LazyJSValue::emit(CCallHelpers& jit, JSValueRegs result) const
 {
     if (m_kind == KnownValue) {
         jit.moveValue(value()->value(), result);
         return;
     }

     // It must be some kind of cell.
 #if USE(JSVALUE32_64)
     jit.move(CCallHelpers::TrustedImm32(JSValue::CellTag), result.tagGPR());
 #endif
     CCallHelpers::DataLabelPtr label = jit.moveWithPatch(
         CCallHelpers::TrustedImmPtr(static_cast<size_t>(0xd1e7beeflu)),
         result.payloadGPR());

     LazyJSValue thisValue = *this;

     // Once we do this, we're committed. Otherwise we leak memory. Note that we call ref/deref
     // manually to ensure that there is no concurrency shadiness. We are doing something here
     // that might be rather brutal: transfering ownership of this string.
     if (m_kind == NewStringImpl)
         thisValue.u.stringImpl->ref();

     CodeBlock* codeBlock = jit.codeBlock();

     jit.addLinkTask(
         [codeBlock, label, thisValue] (LinkBuffer& linkBuffer) {
             JSValue realValue = thisValue.getValue(*codeBlock->vm());
             RELEASE_ASSERT(realValue.isCell());

             codeBlock->addConstant(realValue);

             if (thisValue.m_kind == NewStringImpl)
                 thisValue.u.stringImpl->deref();

             linkBuffer.patch(label, realValue.asCell());
         });
 }

 void LazyJSValue::dumpInContext(PrintStream& out, DumpContext* context) const
 {
     switch (m_kind) {
     case KnownValue:
         value()->dumpInContext(out, context);
         return;
     case SingleCharacterString:
         out.print("Lazy:SingleCharacterString(");
         out.printf("%04X", static_cast<unsigned>(character()));
         out.print(" / ", StringImpl::utf8ForCharacters(&u.character, 1).value(), ")");
         return;
     case KnownStringImpl:
         out.print("Lazy:KnownString(", stringImpl(), ")");
         return;
     case NewStringImpl:
         out.print("Lazy:NewString(", stringImpl(), ")");
         return;
     }
     RELEASE_ASSERT_NOT_REACHED();
 }

 void LazyJSValue::dump(PrintStream& out) const
 {
     dumpInContext(out, 0);
 }

 } } // namespace JSC::DFG

 #endif // ENABLE(DFG_JIT)
	/*
	* Copyright (C) 2013, 2014, 2016 Apple Inc. All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without
	* modification, are permitted provided that the following conditions
	* are met:
	* 1. Redistributions of source code must retain the above copyright
	* notice, this list of conditions and the following disclaimer.
	* 2. Redistributions in binary form must reproduce the above copyright
	* notice, this list of conditions and the following disclaimer in the
	* documentation and/or other materials provided with the distribution.
	*
	* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
	* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
	* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
	* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
	* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
	* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
	* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
	* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*/

	#include "config.h"
	#include "DFGLazyJSValue.h"

	#if ENABLE(DFG_JIT)

	#include "CCallHelpers.h"
	#include "DFGGraph.h"
	#include "JSCInlines.h"
	#include "LinkBuffer.h"

	namespace JSC { namespace DFG {

	LazyJSValue LazyJSValue::newString(Graph& graph, const String& string)
	{
	LazyJSValue result;
	result.m_kind = NewStringImpl;
	result.u.stringImpl = graph.m_localStrings.add(string).iterator->impl();
	return result;
	}

	JSValue LazyJSValue::getValue(VM& vm) const
	{
	switch (m_kind) {
	case KnownValue:
	return value()->value();
	case SingleCharacterString:
	return jsSingleCharacterString(&vm, u.character);
	case KnownStringImpl:
	return jsString(&vm, u.stringImpl);
	case NewStringImpl:
	return jsString(&vm, AtomicStringImpl::add(u.stringImpl));
	}
	RELEASE_ASSERT_NOT_REACHED();
	return JSValue();
	}

	static TriState equalToSingleCharacter(JSValue value, UChar character)
	{
	if (!value.isString())
	return FalseTriState;

	JSString* jsString = asString(value);
	if (jsString->length() != 1)
	return FalseTriState;

	const StringImpl* string = jsString->tryGetValueImpl();
	if (!string)
	return MixedTriState;

	return triState(string->at(0) == character);
	}

	static TriState equalToStringImpl(JSValue value, StringImpl* stringImpl)
	{
	if (!value.isString())
	return FalseTriState;

	JSString* jsString = asString(value);
	const StringImpl* string = jsString->tryGetValueImpl();
	if (!string)
	return MixedTriState;

	return triState(WTF::equal(stringImpl, string));
	}

	const StringImpl* LazyJSValue::tryGetStringImpl(VM& vm) const
	{
	switch (m_kind) {
	case KnownStringImpl:
	case NewStringImpl:
	return u.stringImpl;

	case KnownValue:
	if (JSString* string = value()->dynamicCast<JSString*>(vm))
	return string->tryGetValueImpl();
	return nullptr;

	default:
	return nullptr;
	}
	}

	String LazyJSValue::tryGetString(Graph& graph) const
	{
	switch (m_kind) {
	case NewStringImpl:
	return u.stringImpl;

	case SingleCharacterString:
	return String(&u.character, 1);

	default:
	if (const StringImpl* string = tryGetStringImpl(graph.m_vm)) {
	unsigned ginormousStringLength = 10000;
	if (string->length() > ginormousStringLength)
	return String();

	auto result = graph.m_copiedStrings.add(string, String());
	if (result.isNewEntry)
	result.iterator->value = string->isolatedCopy();
	return result.iterator->value;
	}

	return String();
	}
	}

	TriState LazyJSValue::strictEqual(const LazyJSValue& other) const
	{
	switch (m_kind) {
	case KnownValue:
	switch (other.m_kind) {
	case KnownValue:
	return JSValue::pureStrictEqual(value()->value(), other.value()->value());
	case SingleCharacterString:
	return equalToSingleCharacter(value()->value(), other.character());
	case KnownStringImpl:
	case NewStringImpl:
	return equalToStringImpl(value()->value(), other.stringImpl());
	}
	break;
	case SingleCharacterString:
	switch (other.m_kind) {
	case SingleCharacterString:
	return triState(character() == other.character());
	case KnownStringImpl:
	case NewStringImpl:
	if (other.stringImpl()->length() != 1)
	return FalseTriState;
	return triState(other.stringImpl()->at(0) == character());
	default:
	return other.strictEqual(*this);
	}
	break;
	case KnownStringImpl:
	case NewStringImpl:
	switch (other.m_kind) {
	case KnownStringImpl:
	case NewStringImpl:
	return triState(WTF::equal(stringImpl(), other.stringImpl()));
	default:
	return other.strictEqual(*this);
	}
	break;
	}
	RELEASE_ASSERT_NOT_REACHED();
	return FalseTriState;
	}

	uintptr_t LazyJSValue::switchLookupValue(SwitchKind kind) const
	{
	// NB. Not every kind of JSValue will be able to give you a switch lookup
	// value, and this method will assert, or do bad things, if you use it
	// for a kind of value that can't.
	switch (m_kind) {
	case KnownValue:
	switch (kind) {
	case SwitchImm:
	return value()->value().asInt32();
	case SwitchCell:
	return bitwise_cast<uintptr_t>(value()->value().asCell());
	default:
	RELEASE_ASSERT_NOT_REACHED();
	return 0;
	}
	case SingleCharacterString:
	switch (kind) {
	case SwitchChar:
	return character();
	default:
	RELEASE_ASSERT_NOT_REACHED();
	return 0;
	}
	default:
	RELEASE_ASSERT_NOT_REACHED();
	return 0;
	}
	}

	void LazyJSValue::emit(CCallHelpers& jit, JSValueRegs result) const
	{
	if (m_kind == KnownValue) {
	jit.moveValue(value()->value(), result);
	return;
	}

	// It must be some kind of cell.
	#if USE(JSVALUE32_64)
	jit.move(CCallHelpers::TrustedImm32(JSValue::CellTag), result.tagGPR());
	#endif
	CCallHelpers::DataLabelPtr label = jit.moveWithPatch(
	CCallHelpers::TrustedImmPtr(static_cast<size_t>(0xd1e7beeflu)),
	result.payloadGPR());

	LazyJSValue thisValue = *this;

	// Once we do this, we're committed. Otherwise we leak memory. Note that we call ref/deref
	// manually to ensure that there is no concurrency shadiness. We are doing something here
	// that might be rather brutal: transfering ownership of this string.
	if (m_kind == NewStringImpl)
	thisValue.u.stringImpl->ref();

	CodeBlock* codeBlock = jit.codeBlock();

	jit.addLinkTask(
	[codeBlock, label, thisValue] (LinkBuffer& linkBuffer) {
	JSValue realValue = thisValue.getValue(*codeBlock->vm());
	RELEASE_ASSERT(realValue.isCell());

	codeBlock->addConstant(realValue);

	if (thisValue.m_kind == NewStringImpl)
	thisValue.u.stringImpl->deref();

	linkBuffer.patch(label, realValue.asCell());
	});
	}

	void LazyJSValue::dumpInContext(PrintStream& out, DumpContext* context) const
	{
	switch (m_kind) {
	case KnownValue:
	value()->dumpInContext(out, context);
	return;
	case SingleCharacterString:
	out.print("Lazy:SingleCharacterString(");
	out.printf("%04X", static_cast<unsigned>(character()));
	out.print(" / ", StringImpl::utf8ForCharacters(&u.character, 1).value(), ")");
	return;
	case KnownStringImpl:
	out.print("Lazy:KnownString(", stringImpl(), ")");
	return;
	case NewStringImpl:
	out.print("Lazy:NewString(", stringImpl(), ")");
	return;
	}
	RELEASE_ASSERT_NOT_REACHED();
	}

	void LazyJSValue::dump(PrintStream& out) const
	{
	dumpInContext(out, 0);
	}

	} } // namespace JSC::DFG

	#endif // ENABLE(DFG_JIT)