Source/JavaScriptCore/runtime/CommonSlowPaths.h - WebKit - Git at Google

 /*
  * Copyright (C) 2011, 2012 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.
  */

 #ifndef CommonSlowPaths_h
 #define CommonSlowPaths_h

 #include "CodeBlock.h"
 #include "CodeSpecializationKind.h"
 #include "ExceptionHelpers.h"
 #include "JSArray.h"
 #include "NameInstance.h"

 namespace JSC {

 // The purpose of this namespace is to include slow paths that are shared
 // between the interpreter and baseline JIT. They are written to be agnostic
 // with respect to the slow-path calling convention, but they do rely on the
 // JS code being executed more-or-less directly from bytecode (so the call
 // frame layout is unmodified, making it potentially awkward to use these
 // from any optimizing JIT, like the DFG).

 namespace CommonSlowPaths {

 ALWAYS_INLINE ExecState* arityCheckFor(ExecState* exec, RegisterFile* registerFile, CodeSpecializationKind kind)
 {
     JSFunction* callee = jsCast<JSFunction*>(exec->callee());
     ASSERT(!callee->isHostFunction());
     CodeBlock* newCodeBlock = &callee->jsExecutable()->generatedBytecodeFor(kind);
     int argumentCountIncludingThis = exec->argumentCountIncludingThis();

     // This ensures enough space for the worst case scenario of zero arguments passed by the caller.
     if (!registerFile->grow(exec->registers() + newCodeBlock->numParameters() + newCodeBlock->m_numCalleeRegisters))
         return 0;

     ASSERT(argumentCountIncludingThis < newCodeBlock->numParameters());

     // Too few arguments -- copy call frame and arguments, then fill in missing arguments with undefined.
     size_t delta = newCodeBlock->numParameters() - argumentCountIncludingThis;
     Register* src = exec->registers();
     Register* dst = exec->registers() + delta;

     int i;
     int end = -ExecState::offsetFor(argumentCountIncludingThis);
     for (i = -1; i >= end; --i)
         dst[i] = src[i];

     end -= delta;
     for ( ; i >= end; --i)
         dst[i] = jsUndefined();

     ExecState* newExec = ExecState::create(dst);
     ASSERT((void*)newExec <= registerFile->end());
     return newExec;
 }

 ALWAYS_INLINE bool opInstanceOfSlow(ExecState* exec, JSValue value, JSValue baseVal, JSValue proto)
 {
     ASSERT(!value.isCell() || !baseVal.isCell() || !proto.isCell()
            || !value.isObject() || !baseVal.isObject() || !proto.isObject()
            || !asObject(baseVal)->structure()->typeInfo().implementsDefaultHasInstance());


     // ECMA-262 15.3.5.3:
     // Throw an exception either if baseVal is not an object, or if it does not implement 'HasInstance' (i.e. is a function).
     TypeInfo typeInfo(UnspecifiedType);
     if (!baseVal.isObject() || !(typeInfo = asObject(baseVal)->structure()->typeInfo()).implementsHasInstance()) {
         exec->globalData().exception = createInvalidParamError(exec, "instanceof", baseVal);
         return false;
     }
     ASSERT(typeInfo.type() != UnspecifiedType);

     if (!typeInfo.overridesHasInstance() && !value.isObject())
         return false;

     return asObject(baseVal)->methodTable()->hasInstance(asObject(baseVal), exec, value, proto);
 }

 inline bool opIn(ExecState* exec, JSValue propName, JSValue baseVal)
 {
     if (!baseVal.isObject()) {
         exec->globalData().exception = createInvalidParamError(exec, "in", baseVal);
         return false;
     }

     JSObject* baseObj = asObject(baseVal);

     uint32_t i;
     if (propName.getUInt32(i))
         return baseObj->hasProperty(exec, i);

     if (isName(propName))
         return baseObj->hasProperty(exec, jsCast<NameInstance*>(propName.asCell())->privateName());

     Identifier property(exec, propName.toString(exec)->value(exec));
     if (exec->globalData().exception)
         return false;
     return baseObj->hasProperty(exec, property);
 }

 ALWAYS_INLINE JSValue opResolve(ExecState* exec, Identifier& ident)
 {
     ScopeChainNode* scopeChain = exec->scopeChain();

     ScopeChainIterator iter = scopeChain->begin();
     ScopeChainIterator end = scopeChain->end();
     ASSERT(iter != end);

     do {
         JSObject* o = iter->get();
         PropertySlot slot(o);
         if (o->getPropertySlot(exec, ident, slot))
             return slot.getValue(exec, ident);
     } while (++iter != end);

     exec->globalData().exception = createUndefinedVariableError(exec, ident);
     return JSValue();
 }

 ALWAYS_INLINE JSValue opResolveSkip(ExecState* exec, Identifier& ident, int skip)
 {
     ScopeChainNode* scopeChain = exec->scopeChain();

     ScopeChainIterator iter = scopeChain->begin();
     ScopeChainIterator end = scopeChain->end();
     ASSERT(iter != end);
     CodeBlock* codeBlock = exec->codeBlock();
     bool checkTopLevel = codeBlock->codeType() == FunctionCode && codeBlock->needsFullScopeChain();
     ASSERT(skip || !checkTopLevel);
     if (checkTopLevel && skip--) {
         if (exec->uncheckedR(codeBlock->activationRegister()).jsValue())
             ++iter;
     }
     while (skip--) {
         ++iter;
         ASSERT(iter != end);
     }
     do {
         JSObject* o = iter->get();
         PropertySlot slot(o);
         if (o->getPropertySlot(exec, ident, slot))
             return slot.getValue(exec, ident);
     } while (++iter != end);

     exec->globalData().exception = createUndefinedVariableError(exec, ident);
     return JSValue();
 }

 ALWAYS_INLINE JSValue opResolveWithBase(ExecState* exec, Identifier& ident, Register& baseSlot)
 {
     ScopeChainNode* scopeChain = exec->scopeChain();

     ScopeChainIterator iter = scopeChain->begin();
     ScopeChainIterator end = scopeChain->end();

     // FIXME: add scopeDepthIsZero optimization

     ASSERT(iter != end);

     JSObject* base;
     do {
         base = iter->get();
         PropertySlot slot(base);
         if (base->getPropertySlot(exec, ident, slot)) {
             JSValue result = slot.getValue(exec, ident);
             if (exec->globalData().exception)
                 return JSValue();

             baseSlot = JSValue(base);
             return result;
         }
         ++iter;
     } while (iter != end);

     exec->globalData().exception = createUndefinedVariableError(exec, ident);
     return JSValue();
 }

 ALWAYS_INLINE JSValue opResolveWithThis(ExecState* exec, Identifier& ident, Register& baseSlot)
 {
     ScopeChainNode* scopeChain = exec->scopeChain();

     ScopeChainIterator iter = scopeChain->begin();
     ScopeChainIterator end = scopeChain->end();

     // FIXME: add scopeDepthIsZero optimization

     ASSERT(iter != end);

     JSObject* base;
     do {
         base = iter->get();
         ++iter;
         PropertySlot slot(base);
         if (base->getPropertySlot(exec, ident, slot)) {
             JSValue result = slot.getValue(exec, ident);
             if (exec->globalData().exception)
                 return JSValue();

             // All entries on the scope chain should be EnvironmentRecords (activations etc),
             // other then 'with' object, which are directly referenced from the scope chain,
             // and the global object. If we hit either an EnvironmentRecord or a global
             // object at the end of the scope chain, this is undefined. If we hit a non-
             // EnvironmentRecord within the scope chain, pass the base as the this value.
             if (iter == end || base->structure()->typeInfo().isEnvironmentRecord())
                 baseSlot = jsUndefined();
             else
                 baseSlot = JSValue(base);
             return result;
         }
     } while (iter != end);

     exec->globalData().exception = createUndefinedVariableError(exec, ident);
     return JSValue();
 }

 } } // namespace JSC::CommonSlowPaths

 #endif // CommonSlowPaths_h
	/*
	* Copyright (C) 2011, 2012 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.
	*/

	#ifndef CommonSlowPaths_h
	#define CommonSlowPaths_h

	#include "CodeBlock.h"
	#include "CodeSpecializationKind.h"
	#include "ExceptionHelpers.h"
	#include "JSArray.h"
	#include "NameInstance.h"

	namespace JSC {

	// The purpose of this namespace is to include slow paths that are shared
	// between the interpreter and baseline JIT. They are written to be agnostic
	// with respect to the slow-path calling convention, but they do rely on the
	// JS code being executed more-or-less directly from bytecode (so the call
	// frame layout is unmodified, making it potentially awkward to use these
	// from any optimizing JIT, like the DFG).

	namespace CommonSlowPaths {

	ALWAYS_INLINE ExecState* arityCheckFor(ExecState* exec, RegisterFile* registerFile, CodeSpecializationKind kind)
	{
	JSFunction* callee = jsCast<JSFunction*>(exec->callee());
	ASSERT(!callee->isHostFunction());
	CodeBlock* newCodeBlock = &callee->jsExecutable()->generatedBytecodeFor(kind);
	int argumentCountIncludingThis = exec->argumentCountIncludingThis();

	// This ensures enough space for the worst case scenario of zero arguments passed by the caller.
	if (!registerFile->grow(exec->registers() + newCodeBlock->numParameters() + newCodeBlock->m_numCalleeRegisters))
	return 0;

	ASSERT(argumentCountIncludingThis < newCodeBlock->numParameters());

	// Too few arguments -- copy call frame and arguments, then fill in missing arguments with undefined.
	size_t delta = newCodeBlock->numParameters() - argumentCountIncludingThis;
	Register* src = exec->registers();
	Register* dst = exec->registers() + delta;

	int i;
	int end = -ExecState::offsetFor(argumentCountIncludingThis);
	for (i = -1; i >= end; --i)
	dst[i] = src[i];

	end -= delta;
	for ( ; i >= end; --i)
	dst[i] = jsUndefined();

	ExecState* newExec = ExecState::create(dst);
	ASSERT((void*)newExec <= registerFile->end());
	return newExec;
	}

	ALWAYS_INLINE bool opInstanceOfSlow(ExecState* exec, JSValue value, JSValue baseVal, JSValue proto)
	{
	ASSERT(!value.isCell() \|\| !baseVal.isCell() \|\| !proto.isCell()
	\|\| !value.isObject() \|\| !baseVal.isObject() \|\| !proto.isObject()
	\|\| !asObject(baseVal)->structure()->typeInfo().implementsDefaultHasInstance());


	// ECMA-262 15.3.5.3:
	// Throw an exception either if baseVal is not an object, or if it does not implement 'HasInstance' (i.e. is a function).
	TypeInfo typeInfo(UnspecifiedType);
	if (!baseVal.isObject() \|\| !(typeInfo = asObject(baseVal)->structure()->typeInfo()).implementsHasInstance()) {
	exec->globalData().exception = createInvalidParamError(exec, "instanceof", baseVal);
	return false;
	}
	ASSERT(typeInfo.type() != UnspecifiedType);

	if (!typeInfo.overridesHasInstance() && !value.isObject())
	return false;

	return asObject(baseVal)->methodTable()->hasInstance(asObject(baseVal), exec, value, proto);
	}

	inline bool opIn(ExecState* exec, JSValue propName, JSValue baseVal)
	{
	if (!baseVal.isObject()) {
	exec->globalData().exception = createInvalidParamError(exec, "in", baseVal);
	return false;
	}

	JSObject* baseObj = asObject(baseVal);

	uint32_t i;
	if (propName.getUInt32(i))
	return baseObj->hasProperty(exec, i);

	if (isName(propName))
	return baseObj->hasProperty(exec, jsCast<NameInstance*>(propName.asCell())->privateName());

	Identifier property(exec, propName.toString(exec)->value(exec));
	if (exec->globalData().exception)
	return false;
	return baseObj->hasProperty(exec, property);
	}

	ALWAYS_INLINE JSValue opResolve(ExecState* exec, Identifier& ident)
	{
	ScopeChainNode* scopeChain = exec->scopeChain();

	ScopeChainIterator iter = scopeChain->begin();
	ScopeChainIterator end = scopeChain->end();
	ASSERT(iter != end);

	do {
	JSObject* o = iter->get();
	PropertySlot slot(o);
	if (o->getPropertySlot(exec, ident, slot))
	return slot.getValue(exec, ident);
	} while (++iter != end);

	exec->globalData().exception = createUndefinedVariableError(exec, ident);
	return JSValue();
	}

	ALWAYS_INLINE JSValue opResolveSkip(ExecState* exec, Identifier& ident, int skip)
	{
	ScopeChainNode* scopeChain = exec->scopeChain();

	ScopeChainIterator iter = scopeChain->begin();
	ScopeChainIterator end = scopeChain->end();
	ASSERT(iter != end);
	CodeBlock* codeBlock = exec->codeBlock();
	bool checkTopLevel = codeBlock->codeType() == FunctionCode && codeBlock->needsFullScopeChain();
	ASSERT(skip \|\| !checkTopLevel);
	if (checkTopLevel && skip--) {
	if (exec->uncheckedR(codeBlock->activationRegister()).jsValue())
	++iter;
	}
	while (skip--) {
	++iter;
	ASSERT(iter != end);
	}
	do {
	JSObject* o = iter->get();
	PropertySlot slot(o);
	if (o->getPropertySlot(exec, ident, slot))
	return slot.getValue(exec, ident);
	} while (++iter != end);

	exec->globalData().exception = createUndefinedVariableError(exec, ident);
	return JSValue();
	}

	ALWAYS_INLINE JSValue opResolveWithBase(ExecState* exec, Identifier& ident, Register& baseSlot)
	{
	ScopeChainNode* scopeChain = exec->scopeChain();

	ScopeChainIterator iter = scopeChain->begin();
	ScopeChainIterator end = scopeChain->end();

	// FIXME: add scopeDepthIsZero optimization

	ASSERT(iter != end);

	JSObject* base;
	do {
	base = iter->get();
	PropertySlot slot(base);
	if (base->getPropertySlot(exec, ident, slot)) {
	JSValue result = slot.getValue(exec, ident);
	if (exec->globalData().exception)
	return JSValue();

	baseSlot = JSValue(base);
	return result;
	}
	++iter;
	} while (iter != end);

	exec->globalData().exception = createUndefinedVariableError(exec, ident);
	return JSValue();
	}

	ALWAYS_INLINE JSValue opResolveWithThis(ExecState* exec, Identifier& ident, Register& baseSlot)
	{
	ScopeChainNode* scopeChain = exec->scopeChain();

	ScopeChainIterator iter = scopeChain->begin();
	ScopeChainIterator end = scopeChain->end();

	// FIXME: add scopeDepthIsZero optimization

	ASSERT(iter != end);

	JSObject* base;
	do {
	base = iter->get();
	++iter;
	PropertySlot slot(base);
	if (base->getPropertySlot(exec, ident, slot)) {
	JSValue result = slot.getValue(exec, ident);
	if (exec->globalData().exception)
	return JSValue();

	// All entries on the scope chain should be EnvironmentRecords (activations etc),
	// other then 'with' object, which are directly referenced from the scope chain,
	// and the global object. If we hit either an EnvironmentRecord or a global
	// object at the end of the scope chain, this is undefined. If we hit a non-
	// EnvironmentRecord within the scope chain, pass the base as the this value.
	if (iter == end \|\| base->structure()->typeInfo().isEnvironmentRecord())
	baseSlot = jsUndefined();
	else
	baseSlot = JSValue(base);
	return result;
	}
	} while (iter != end);

	exec->globalData().exception = createUndefinedVariableError(exec, ident);
	return JSValue();
	}

	} } // namespace JSC::CommonSlowPaths

	#endif // CommonSlowPaths_h