Source/JavaScriptCore/runtime/JSFunctionInlines.h

/*
 * Copyright (C) 2013-2018 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. 
 */

#pragma once

#include "FunctionExecutable.h"
#include "JSBoundFunction.h"
#include "JSFunction.h"
#include "JSRemoteFunction.h"
#include "NativeExecutable.h"

namespace JSC {

inline JSFunction* JSFunction::createWithInvalidatedReallocationWatchpoint(
    VM& vm, FunctionExecutable* executable, JSScope* scope)
{
    ASSERT(executable->singleton().hasBeenInvalidated());
    return createImpl(vm, executable, scope, selectStructureForNewFuncExp(scope->globalObject(), executable));
}

inline JSFunction::JSFunction(VM& vm, FunctionExecutable* executable, JSScope* scope, Structure* structure)
    : Base(vm, scope, structure)
    , m_executableOrRareData(bitwise_cast<uintptr_t>(executable))
{
    assertTypeInfoFlagInvariants();
}

inline FunctionExecutable* JSFunction::jsExecutable() const
{
    ASSERT(!isHostFunctionNonInline());
    return static_cast<FunctionExecutable*>(executable());
}

inline bool JSFunction::isHostFunction() const
{
    ASSERT(executable());
    return executable()->isHostFunction();
}

inline Intrinsic JSFunction::intrinsic() const
{
    return executable()->intrinsic();
}

inline bool JSFunction::isBuiltinFunction() const
{
    return !isHostFunction() && jsExecutable()->isBuiltinFunction();
}

inline bool JSFunction::isHostOrBuiltinFunction() const
{
    return isHostFunction() || isBuiltinFunction();
}

inline bool JSFunction::isClassConstructorFunction() const
{
    return !isHostFunction() && jsExecutable()->isClassConstructorFunction();
}

inline bool JSFunction::isRemoteFunction() const
{
    return inherits<JSRemoteFunction>();
}

inline TaggedNativeFunction JSFunction::nativeFunction()
{
    ASSERT(isHostFunctionNonInline());
    return static_cast<NativeExecutable*>(executable())->function();
}

inline TaggedNativeFunction JSFunction::nativeConstructor()
{
    ASSERT(isHostFunctionNonInline());
    return static_cast<NativeExecutable*>(executable())->constructor();
}

inline bool isHostFunction(JSValue value, TaggedNativeFunction nativeFunction)
{
    JSFunction* function = jsCast<JSFunction*>(getJSFunction(value));
    if (!function || !function->isHostFunction())
        return false;
    return function->nativeFunction() == nativeFunction;
}

inline bool isRemoteFunction(JSValue value)
{
    return value.inherits<JSRemoteFunction>();
}

inline bool JSFunction::hasReifiedLength() const
{
    if (FunctionRareData* rareData = this->rareData())
        return rareData->hasReifiedLength();
    return false;
}

inline bool JSFunction::hasReifiedName() const
{
    if (FunctionRareData* rareData = this->rareData())
        return rareData->hasReifiedName();
    return false;
}

inline double JSFunction::originalLength(VM& vm)
{
    if (inherits<JSBoundFunction>())
        return jsCast<JSBoundFunction*>(this)->length(vm);
    if (inherits<JSRemoteFunction>())
        return jsCast<JSRemoteFunction*>(this)->length(vm);
    ASSERT(!isHostFunction());
    return jsExecutable()->parameterCount();
}

template<typename... StringTypes>
ALWAYS_INLINE String makeNameWithOutOfMemoryCheck(JSGlobalObject* globalObject, ThrowScope& throwScope, const char* messagePrefix, StringTypes... strings)
{
    String name = tryMakeString(strings...);
    if (UNLIKELY(!name)) {
        throwOutOfMemoryError(globalObject, throwScope, makeString(messagePrefix, "name is too long"_s));
        return String();
    }
    return name;
}

inline JSString* JSFunction::originalName(JSGlobalObject* globalObject)
{
    VM& vm = globalObject->vm();
    auto scope = DECLARE_THROW_SCOPE(vm);

    if (this->inherits<JSBoundFunction>()) {
        JSString* nameMayBeNull = jsCast<JSBoundFunction*>(this)->nameMayBeNull();
        if (nameMayBeNull)
            RELEASE_AND_RETURN(scope, jsString(globalObject, vm.smallStrings.boundPrefixString(), nameMayBeNull));
        return jsEmptyString(vm);
    }

    if (this->inherits<JSRemoteFunction>()) {
        JSString* nameMayBeNull = jsCast<JSRemoteFunction*>(this)->nameMayBeNull();
        if (nameMayBeNull)
            return nameMayBeNull;
        return jsEmptyString(vm);
    }

    ASSERT(!isHostFunction());
    const Identifier& ecmaName = jsExecutable()->ecmaName();
    String name;
    // https://tc39.github.io/ecma262/#sec-exports-runtime-semantics-evaluation
    // When the ident is "*default*", we need to set "default" for the ecma name.
    // This "*default*" name is never shown to users.
    if (ecmaName == vm.propertyNames->starDefaultPrivateName)
        name = vm.propertyNames->defaultKeyword.string();
    else
        name = ecmaName.string();

    if (globalObject->needsSiteSpecificQuirks()) {
        auto illegalCharMatcher = [] (UChar ch) -> bool {
            return ch == ' ' || ch == '|';
        };
        if (name.find(illegalCharMatcher) != notFound)
            name = String();
    }

    if (jsExecutable()->isGetter()) {
        name = makeNameWithOutOfMemoryCheck(globalObject, scope, "Getter ", "get ", name);
        RETURN_IF_EXCEPTION(scope, { });
    } else if (jsExecutable()->isSetter()) {
        name = makeNameWithOutOfMemoryCheck(globalObject, scope, "Setter ", "set ", name);
        RETURN_IF_EXCEPTION(scope, { });
    }
    return jsString(vm, WTFMove(name));
}

inline bool JSFunction::canAssumeNameAndLengthAreOriginal(VM&)
{
    if (isHostFunction()) {
        // Bound functions are not eagerly generating name and length.
        // Thus, we can use FunctionRareData's tracking. This is useful to optimize func.bind().bind() case.
        if (!inherits<JSBoundFunction>())
            return false;
    }
    FunctionRareData* rareData = this->rareData();
    if (!rareData)
        return true;
    if (rareData->hasModifiedNameForBoundOrNonHostFunction())
        return false;
    if (rareData->hasModifiedLengthForBoundOrNonHostFunction())
        return false;
    return true;
}

inline bool JSFunction::mayHaveNonReifiedPrototype()
{
    return !isHostOrBuiltinFunction() && jsExecutable()->hasPrototypeProperty();
}

inline bool JSFunction::canUseAllocationProfile()
{
    if (isHostOrBuiltinFunction()) {
        if (isHostFunction())
            return false;

        VM& vm = globalObject()->vm();
        unsigned attributes;
        JSValue prototype = getDirect(vm, vm.propertyNames->prototype, attributes);
        if (!prototype || (attributes & PropertyAttribute::AccessorOrCustomAccessorOrValue))
            return false;
    }

    // If we don't have a prototype property, we're not guaranteed it's
    // non-configurable. For example, user code can define the prototype
    // as a getter. JS semantics require that the getter is called every
    // time |construct| occurs with this function as new.target.
    return jsExecutable()->hasPrototypeProperty();
}

inline FunctionRareData* JSFunction::ensureRareDataAndAllocationProfile(JSGlobalObject* globalObject, unsigned inlineCapacity)
{
    ASSERT(canUseAllocationProfile());
    FunctionRareData* rareData = this->rareData();
    if (!rareData)
        return allocateAndInitializeRareData(globalObject, inlineCapacity);
    if (UNLIKELY(!rareData->isObjectAllocationProfileInitialized()))
        return initializeRareData(globalObject, inlineCapacity);
    return rareData;
}

inline JSString* JSFunction::asStringConcurrently() const
{
    if (inherits<JSBoundFunction>() || inherits<JSRemoteFunction>())
        return nullptr;
    if (isHostFunction())
        return static_cast<NativeExecutable*>(executable())->asStringConcurrently();
    return jsExecutable()->asStringConcurrently();
}

} // namespace JSC