runtime/StructureIDBlob.h

   1 /*
   2  * Copyright (C) 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. AND ITS CONTRIBUTORS ``AS IS''
  14  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  15  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  16  * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS
  17  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  18  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  19  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  20  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  21  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  22  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
  23  * THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26 #ifndef StructureIDBlob_h
  27 #define StructureIDBlob_h
  28
  29 #include "IndexingType.h"
  30 #include "JSTypeInfo.h"
  31 #include "StructureIDTable.h"
  32
  33 namespace JSC {
  34
  35 class StructureIDBlob {
  36     friend class LLIntOffsetsExtractor;
  37 public:
  38     StructureIDBlob()
  39     {
  40         u.doubleWord = 0xbbadbeef;
  41     }
  42
  43     StructureIDBlob(StructureID structureID, IndexingType indexingType, const TypeInfo& typeInfo)
  44     {
  45         u.fields.structureID = structureID;
  46         u.fields.indexingType = indexingType;
  47         u.fields.type = typeInfo.type();
  48         u.fields.inlineTypeFlags = typeInfo.inlineTypeFlags();
  49         u.fields.defaultGCData = JSCell::NotMarked;
  50     }
  51
  52     void operator=(const StructureIDBlob& other) { u.doubleWord = other.u.doubleWord; }
  53
  54     StructureID structureID() const { return u.fields.structureID; }
  55     IndexingType indexingType() const { return u.fields.indexingType; }
  56     void setIndexingType(IndexingType indexingType) { u.fields.indexingType = indexingType; }
  57     JSType type() const { return u.fields.type; }
  58     TypeInfo::InlineTypeFlags inlineTypeFlags() const { return u.fields.inlineTypeFlags; }
  59
  60     TypeInfo typeInfo(TypeInfo::OutOfLineTypeFlags outOfLineTypeFlags) const { return TypeInfo(type(), inlineTypeFlags(), outOfLineTypeFlags); }
  61
  62     int32_t blobExcludingStructureID() const { return u.words.word2; }
  63     int64_t blob() const { return u.doubleWord; }
  64
  65     static ptrdiff_t structureIDOffset()
  66     {
  67         return OBJECT_OFFSETOF(StructureIDBlob, u.fields.structureID);
  68     }
  69
  70     static ptrdiff_t indexingTypeOffset()
  71     {
  72         return OBJECT_OFFSETOF(StructureIDBlob, u.fields.indexingType);
  73     }
  74
  75 private:
  76     union {
  77         struct {
  78             StructureID structureID;
  79             IndexingType indexingType;
  80             JSType type;
  81             TypeInfo::InlineTypeFlags inlineTypeFlags;
  82             JSCell::GCData defaultGCData;
  83         } fields;
  84         struct {
  85             int32_t word1;
  86             int32_t word2;
  87         } words;
  88         int64_t doubleWord;
  89     } u;
  90 };
  91
  92 } // namespace JSC
  93
  94 #endif // StructureIDBlob_h