Source/JavaScriptCore/dfg/DFGUseKind.h

/*
 * Copyright (C) 2013-2020 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
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 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
 */

#pragma once

#if ENABLE(DFG_JIT)

#include "DFGNodeFlags.h"
#include "SpeculatedType.h"
#include <wtf/PrintStream.h>

namespace JSC { namespace DFG {

enum UseKind : uint8_t {
    // The DFG has 3 representations of values used:

    // 1. The JSValue representation for a JSValue that must be stored in a GP
    //    register (or a GP register pair), and follows rules for boxing and unboxing
    //    that allow the JSValue to be stored as either fully boxed JSValues, or
    //    unboxed Int32, Booleans, Cells, etc. in 32-bit as appropriate.
    UntypedUse, // UntypedUse must come first (value 0).
    Int32Use,
    KnownInt32Use,
    AnyIntUse,
    NumberUse,
    RealNumberUse,
    BooleanUse,
    KnownBooleanUse,
    CellUse,
    KnownCellUse,
    CellOrOtherUse,
    ObjectUse,
    ArrayUse,
    FunctionUse,
    FinalObjectUse,
    PromiseObjectUse,
    RegExpObjectUse,
    ProxyObjectUse,
    DerivedArrayUse,
    ObjectOrOtherUse,
    StringIdentUse,
    StringUse,
    StringOrOtherUse,
    KnownStringUse,
    KnownPrimitiveUse, // This bizarre type arises for op_strcat, which has a bytecode guarantee that it will only see primitives (i.e. not objects).
    SymbolUse,
    AnyBigIntUse,
    HeapBigIntUse,
    BigInt32Use,
    DateObjectUse,
    MapObjectUse,
    SetObjectUse,
    WeakMapObjectUse,
    WeakSetObjectUse,
    DataViewObjectUse,
    StringObjectUse,
    StringOrStringObjectUse,
    NotStringVarUse,
    NotSymbolUse,
    NotCellUse,
    NotCellNorBigIntUse,
    NotDoubleUse,
    NeitherDoubleNorHeapBigIntUse,
    NeitherDoubleNorHeapBigIntNorStringUse,
    KnownOtherUse,
    OtherUse,
    MiscUse,

    // 2. The Double representation for an unboxed double value that must be stored
    //    in an FP register.
    DoubleRepUse,
    DoubleRepRealUse,
    DoubleRepAnyIntUse,

    // 3. The Int52 representation for an unboxed integer value that must be stored
    //    in a GP register.
    Int52RepUse,

    LastUseKind // Must always be the last entry in the enum, as it is used to denote the number of enum elements.
};

inline SpeculatedType typeFilterFor(UseKind useKind)
{
    switch (useKind) {
    case UntypedUse:
        return SpecBytecodeTop;
    case Int32Use:
    case KnownInt32Use:
        return SpecInt32Only;
    case Int52RepUse:
        return SpecInt52Any;
    case AnyIntUse:
        return SpecInt32Only | SpecAnyIntAsDouble;
    case NumberUse:
        return SpecBytecodeNumber;
    case RealNumberUse:
        return SpecBytecodeRealNumber;
    case DoubleRepUse:
        return SpecFullDouble;
    case DoubleRepRealUse:
        return SpecDoubleReal;
    case DoubleRepAnyIntUse:
        return SpecAnyIntAsDouble;
    case BooleanUse:
    case KnownBooleanUse:
        return SpecBoolean;
    case CellUse:
    case KnownCellUse:
        return SpecCellCheck;
    case CellOrOtherUse:
        return SpecCellCheck | SpecOther;
    case ObjectUse:
        return SpecObject;
    case ArrayUse:
        return SpecArray;
    case FunctionUse:
        return SpecFunction;
    case FinalObjectUse:
        return SpecFinalObject;
    case RegExpObjectUse:
        return SpecRegExpObject;
    case ProxyObjectUse:
        return SpecProxyObject;
    case DerivedArrayUse:
        return SpecDerivedArray;
    case ObjectOrOtherUse:
        return SpecObject | SpecOther;
    case StringIdentUse:
        return SpecStringIdent;
    case StringUse:
    case KnownStringUse:
        return SpecString;
    case StringOrOtherUse:
        return SpecString | SpecOther;
    case KnownPrimitiveUse:
        return SpecHeapTop & ~SpecObject;
    case SymbolUse:
        return SpecSymbol;
    case AnyBigIntUse:
        return SpecBigInt;
    case HeapBigIntUse:
        return SpecHeapBigInt;
    case BigInt32Use:
        return SpecBigInt32;
    case PromiseObjectUse:
        return SpecPromiseObject;
    case DateObjectUse:
        return SpecDateObject;
    case MapObjectUse:
        return SpecMapObject;
    case SetObjectUse:
        return SpecSetObject;
    case WeakMapObjectUse:
        return SpecWeakMapObject;
    case WeakSetObjectUse:
        return SpecWeakSetObject;
    case DataViewObjectUse:
        return SpecDataViewObject;
    case StringObjectUse:
        return SpecStringObject;
    case StringOrStringObjectUse:
        return SpecString | SpecStringObject;
    case NotStringVarUse:
        return ~SpecStringVar;
    case NotSymbolUse:
        return ~SpecSymbol;
    case NotCellUse:
        return ~SpecCellCheck;
    case NotCellNorBigIntUse:
        return ~SpecCellCheck & ~SpecBigInt;
    case NotDoubleUse:
        return ~SpecFullDouble;
    case NeitherDoubleNorHeapBigIntUse:
        return ~SpecFullDouble & ~SpecHeapBigInt;
    case NeitherDoubleNorHeapBigIntNorStringUse:
        return ~(SpecFullDouble | SpecHeapBigInt | SpecString);
    case KnownOtherUse:
    case OtherUse:
        return SpecOther;
    case MiscUse:
        return SpecMisc;
    default:
        RELEASE_ASSERT_NOT_REACHED();
        return SpecFullTop;
    }
}

inline bool shouldNotHaveTypeCheck(UseKind kind)
{
    switch (kind) {
    case UntypedUse:
    case KnownInt32Use:
    case KnownCellUse:
    case KnownStringUse:
    case KnownPrimitiveUse:
    case KnownBooleanUse:
    case KnownOtherUse:
    case Int52RepUse:
    case DoubleRepUse:
        return true;
    default:
        return false;
    }
}

inline bool mayHaveTypeCheck(UseKind kind)
{
    return !shouldNotHaveTypeCheck(kind);
}

inline bool isDouble(UseKind kind)
{
    switch (kind) {
    case DoubleRepUse:
    case DoubleRepRealUse:
    case DoubleRepAnyIntUse:
        return true;
    default:
        return false;
    }
}

// Returns true if the use kind only admits cells, and is therefore appropriate for
// SpeculateCellOperand in the DFG or lowCell() in the FTL.
inline bool isCell(UseKind kind)
{
    switch (kind) {
    case CellUse:
    case KnownCellUse:
    case ObjectUse:
    case ArrayUse:
    case FunctionUse:
    case FinalObjectUse:
    case RegExpObjectUse:
    case PromiseObjectUse:
    case ProxyObjectUse:
    case DerivedArrayUse:
    case StringIdentUse:
    case StringUse:
    case KnownStringUse:
    case SymbolUse:
    case HeapBigIntUse:
    case StringObjectUse:
    case StringOrStringObjectUse:
    case DateObjectUse:
    case MapObjectUse:
    case SetObjectUse:
    case WeakMapObjectUse:
    case WeakSetObjectUse:
    case DataViewObjectUse:
        return true;
    default:
        return false;
    }
}

// Returns true if we've already guaranteed the type 
inline bool alreadyChecked(UseKind kind, SpeculatedType type)
{
    return !(type & ~typeFilterFor(kind));
}

inline UseKind useKindForResult(NodeFlags result)
{
    ASSERT(!(result & ~NodeResultMask));
    switch (result) {
    case NodeResultInt52:
        return Int52RepUse;
    case NodeResultDouble:
        return DoubleRepUse;
    default:
        return UntypedUse;
    }
}

inline bool checkMayCrashIfInputIsEmpty(UseKind kind)
{
#if USE(JSVALUE64)
    switch (kind) {
    case UntypedUse:
    case Int32Use:
    case KnownInt32Use:
    case AnyIntUse:
    case NumberUse:
    case BooleanUse:
    case KnownBooleanUse:
    case CellUse:
    case KnownCellUse:
    case CellOrOtherUse:
    case KnownOtherUse:
    case OtherUse:
    case MiscUse:
    case NotCellUse:
    case NotCellNorBigIntUse:
    case NotDoubleUse:
    case NeitherDoubleNorHeapBigIntUse:
    case NeitherDoubleNorHeapBigIntNorStringUse:
        return false;
    default:
        return true;
    }
#else
    UNUSED_PARAM(kind);
    return true;
#endif
}

} } // namespace JSC::DFG

namespace WTF {

void printInternal(PrintStream&, JSC::DFG::UseKind);

} // namespace WTF

#endif // ENABLE(DFG_JIT)