dfg/DFGLazyJSValue.cpp

   1 /*
   2  * Copyright (C) 2013, 2014 Apple Inc. All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. Redistributions in binary form must reproduce the above copyright
  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
  12  *
  13  * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
  14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
  17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26 #include "config.h"
  27 #include "DFGLazyJSValue.h"
  28
  29 #if ENABLE(DFG_JIT)
  30
  31 #include "JSCInlines.h"
  32
  33 namespace JSC { namespace DFG {
  34
  35 JSValue LazyJSValue::getValue(VM& vm) const
  36 {
  37     switch (m_kind) {
  38     case KnownValue:
  39         return value()->value();
  40     case SingleCharacterString:
  41         return jsSingleCharacterString(&vm, u.character);
  42     case KnownStringImpl:
  43         return jsString(&vm, u.stringImpl);
  44     }
  45     RELEASE_ASSERT_NOT_REACHED();
  46     return JSValue();
  47 }
  48
  49 static TriState equalToSingleCharacter(JSValue value, UChar character)
  50 {
  51     if (!value.isString())
  52         return FalseTriState;
  53
  54     JSString* jsString = asString(value);
  55     if (jsString->length() != 1)
  56         return FalseTriState;
  57
  58     const StringImpl* string = jsString->tryGetValueImpl();
  59     if (!string)
  60         return MixedTriState;
  61
  62     return triState(string->at(0) == character);
  63 }
  64
  65 static TriState equalToStringImpl(JSValue value, StringImpl* stringImpl)
  66 {
  67     if (!value.isString())
  68         return FalseTriState;
  69
  70     JSString* jsString = asString(value);
  71     const StringImpl* string = jsString->tryGetValueImpl();
  72     if (!string)
  73         return MixedTriState;
  74
  75     return triState(WTF::equal(stringImpl, string));
  76 }
  77
  78 TriState LazyJSValue::strictEqual(const LazyJSValue& other) const
  79 {
  80     switch (m_kind) {
  81     case KnownValue:
  82         switch (other.m_kind) {
  83         case KnownValue:
  84             return JSValue::pureStrictEqual(value()->value(), other.value()->value());
  85         case SingleCharacterString:
  86             return equalToSingleCharacter(value()->value(), other.character());
  87         case KnownStringImpl:
  88             return equalToStringImpl(value()->value(), other.stringImpl());
  89         }
  90         break;
  91     case SingleCharacterString:
  92         switch (other.m_kind) {
  93         case SingleCharacterString:
  94             return triState(character() == other.character());
  95         case KnownStringImpl:
  96             if (other.stringImpl()->length() != 1)
  97                 return FalseTriState;
  98             return triState(other.stringImpl()->at(0) == character());
  99         default:
 100             return other.strictEqual(*this);
 101         }
 102         break;
 103     case KnownStringImpl:
 104         switch (other.m_kind) {
 105         case KnownStringImpl:
 106             return triState(WTF::equal(stringImpl(), other.stringImpl()));
 107         default:
 108             return other.strictEqual(*this);
 109         }
 110         break;
 111     }
 112     RELEASE_ASSERT_NOT_REACHED();
 113     return FalseTriState;
 114 }
 115
 116 uintptr_t LazyJSValue::switchLookupValue(SwitchKind kind) const
 117 {
 118     // NB. Not every kind of JSValue will be able to give you a switch lookup
 119     // value, and this method will assert, or do bad things, if you use it
 120     // for a kind of value that can't.
 121     switch (m_kind) {
 122     case KnownValue:
 123         switch (kind) {
 124         case SwitchImm:
 125             return value()->value().asInt32();
 126         case SwitchCell:
 127             return bitwise_cast<uintptr_t>(value()->value().asCell());
 128         default:
 129             RELEASE_ASSERT_NOT_REACHED();
 130             return 0;
 131         }
 132     case SingleCharacterString:
 133         switch (kind) {
 134         case SwitchChar:
 135             return character();
 136         default:
 137             RELEASE_ASSERT_NOT_REACHED();
 138             return 0;
 139         }
 140     default:
 141         RELEASE_ASSERT_NOT_REACHED();
 142         return 0;
 143     }
 144 }
 145
 146 void LazyJSValue::dumpInContext(PrintStream& out, DumpContext* context) const
 147 {
 148     switch (m_kind) {
 149     case KnownValue:
 150         value()->dumpInContext(out, context);
 151         return;
 152     case SingleCharacterString:
 153         out.print("Lazy:SingleCharacterString(");
 154         out.printf("%04X", static_cast<unsigned>(character()));
 155         out.print(" / ", StringImpl::utf8ForCharacters(&u.character, 1), ")");
 156         return;
 157     case KnownStringImpl:
 158         out.print("Lazy:String(", stringImpl(), ")");
 159         return;
 160     }
 161     RELEASE_ASSERT_NOT_REACHED();
 162 }
 163
 164 void LazyJSValue::dump(PrintStream& out) const
 165 {
 166     dumpInContext(out, 0);
 167 }
 168
 169 } } // namespace JSC::DFG
 170
 171 #endif // ENABLE(DFG_JIT)
 172