bytecode/ArrayProfile.h

   1 /*
   2  * Copyright (C) 2012, 2013 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 #ifndef ArrayProfile_h
  27 #define ArrayProfile_h
  28
  29 #include "ConcurrentJITLock.h"
  30 #include "JSArray.h"
  31 #include "Structure.h"
  32 #include <wtf/HashMap.h>
  33 #include <wtf/SegmentedVector.h>
  34
  35 namespace JSC {
  36
  37 class CodeBlock;
  38 class LLIntOffsetsExtractor;
  39
  40 // This is a bitfield where each bit represents an type of array access that we have seen.
  41 // There are 16 indexing types that use the lower bits.
  42 // There are 9 typed array types taking the bits 16 to 25.
  43 typedef unsigned ArrayModes;
  44
  45 const ArrayModes Int8ArrayMode = 1 << 16;
  46 const ArrayModes Int16ArrayMode = 1 << 17;
  47 const ArrayModes Int32ArrayMode = 1 << 18;
  48 const ArrayModes Uint8ArrayMode = 1 << 19;
  49 const ArrayModes Uint8ClampedArrayMode = 1 << 20;
  50 const ArrayModes Uint16ArrayMode = 1 << 21;
  51 const ArrayModes Uint32ArrayMode = 1 << 22;
  52 const ArrayModes Float32ArrayMode = 1 << 23;
  53 const ArrayModes Float64ArrayMode = 1 << 24;
  54
  55 #define asArrayModes(type) \
  56     (static_cast<unsigned>(1) << static_cast<unsigned>(type))
  57
  58 #define ALL_TYPED_ARRAY_MODES \
  59     (Int8ArrayMode            \
  60     | Int16ArrayMode          \
  61     | Int32ArrayMode          \
  62     | Uint8ArrayMode          \
  63     | Uint8ClampedArrayMode   \
  64     | Uint16ArrayMode         \
  65     | Uint32ArrayMode         \
  66     | Float32ArrayMode        \
  67     | Float64ArrayMode        \
  68     )
  69
  70 #define ALL_NON_ARRAY_ARRAY_MODES                       \
  71     (asArrayModes(NonArray)                             \
  72     | asArrayModes(NonArrayWithInt32)                   \
  73     | asArrayModes(NonArrayWithDouble)                  \
  74     | asArrayModes(NonArrayWithContiguous)              \
  75     | asArrayModes(NonArrayWithArrayStorage)            \
  76     | asArrayModes(NonArrayWithSlowPutArrayStorage)     \
  77     | ALL_TYPED_ARRAY_MODES)
  78
  79 #define ALL_ARRAY_ARRAY_MODES                           \
  80     (asArrayModes(ArrayClass)                           \
  81     | asArrayModes(ArrayWithUndecided)                  \
  82     | asArrayModes(ArrayWithInt32)                      \
  83     | asArrayModes(ArrayWithDouble)                     \
  84     | asArrayModes(ArrayWithContiguous)                 \
  85     | asArrayModes(ArrayWithArrayStorage)               \
  86     | asArrayModes(ArrayWithSlowPutArrayStorage))
  87
  88 #define ALL_ARRAY_MODES (ALL_NON_ARRAY_ARRAY_MODES | ALL_ARRAY_ARRAY_MODES)
  89
  90 inline ArrayModes arrayModeFromStructure(Structure* structure)
  91 {
  92     switch (structure->classInfo()->typedArrayStorageType) {
  93     case TypeInt8:
  94         return Int8ArrayMode;
  95     case TypeUint8:
  96         return Uint8ArrayMode;
  97     case TypeUint8Clamped:
  98         return Uint8ClampedArrayMode;
  99     case TypeInt16:
 100         return Int16ArrayMode;
 101     case TypeUint16:
 102         return Uint16ArrayMode;
 103     case TypeInt32:
 104         return Int32ArrayMode;
 105     case TypeUint32:
 106         return Uint32ArrayMode;
 107     case TypeFloat32:
 108         return Float32ArrayMode;
 109     case TypeFloat64:
 110         return Float64ArrayMode;
 111     case TypeDataView:
 112     case NotTypedArray:
 113         break;
 114     }
 115     return asArrayModes(structure->indexingType());
 116 }
 117
 118 void dumpArrayModes(PrintStream&, ArrayModes);
 119 MAKE_PRINT_ADAPTOR(ArrayModesDump, ArrayModes, dumpArrayModes);
 120
 121 inline bool mergeArrayModes(ArrayModes& left, ArrayModes right)
 122 {
 123     ArrayModes newModes = left | right;
 124     if (newModes == left)
 125         return false;
 126     left = newModes;
 127     return true;
 128 }
 129
 130 inline bool arrayModesAreClearOrTop(ArrayModes modes)
 131 {
 132     return !modes || modes == ALL_ARRAY_MODES;
 133 }
 134
 135 // Checks if proven is a subset of expected.
 136 inline bool arrayModesAlreadyChecked(ArrayModes proven, ArrayModes expected)
 137 {
 138     return (expected | proven) == expected;
 139 }
 140
 141 inline bool arrayModesInclude(ArrayModes arrayModes, IndexingType shape)
 142 {
 143     return !!(arrayModes & (asArrayModes(NonArray | shape) | asArrayModes(ArrayClass | shape)));
 144 }
 145
 146 inline bool shouldUseSlowPutArrayStorage(ArrayModes arrayModes)
 147 {
 148     return arrayModesInclude(arrayModes, SlowPutArrayStorageShape);
 149 }
 150
 151 inline bool shouldUseFastArrayStorage(ArrayModes arrayModes)
 152 {
 153     return arrayModesInclude(arrayModes, ArrayStorageShape);
 154 }
 155
 156 inline bool shouldUseContiguous(ArrayModes arrayModes)
 157 {
 158     return arrayModesInclude(arrayModes, ContiguousShape);
 159 }
 160
 161 inline bool shouldUseDouble(ArrayModes arrayModes)
 162 {
 163     return arrayModesInclude(arrayModes, DoubleShape);
 164 }
 165
 166 inline bool shouldUseInt32(ArrayModes arrayModes)
 167 {
 168     return arrayModesInclude(arrayModes, Int32Shape);
 169 }
 170
 171 inline bool hasSeenArray(ArrayModes arrayModes)
 172 {
 173     return arrayModes & ALL_ARRAY_ARRAY_MODES;
 174 }
 175
 176 inline bool hasSeenNonArray(ArrayModes arrayModes)
 177 {
 178     return arrayModes & ALL_NON_ARRAY_ARRAY_MODES;
 179 }
 180
 181 class ArrayProfile {
 182 public:
 183     ArrayProfile()
 184         : m_bytecodeOffset(std::numeric_limits<unsigned>::max())
 185         , m_lastSeenStructureID(0)
 186         , m_mayStoreToHole(false)
 187         , m_outOfBounds(false)
 188         , m_mayInterceptIndexedAccesses(false)
 189         , m_usesOriginalArrayStructures(true)
 190         , m_didPerformFirstRunPruning(false)
 191         , m_observedArrayModes(0)
 192     {
 193     }
 194
 195     ArrayProfile(unsigned bytecodeOffset)
 196         : m_bytecodeOffset(bytecodeOffset)
 197         , m_lastSeenStructureID(0)
 198         , m_mayStoreToHole(false)
 199         , m_outOfBounds(false)
 200         , m_mayInterceptIndexedAccesses(false)
 201         , m_usesOriginalArrayStructures(true)
 202         , m_didPerformFirstRunPruning(false)
 203         , m_observedArrayModes(0)
 204     {
 205     }
 206
 207     unsigned bytecodeOffset() const { return m_bytecodeOffset; }
 208
 209     StructureID* addressOfLastSeenStructureID() { return &m_lastSeenStructureID; }
 210     ArrayModes* addressOfArrayModes() { return &m_observedArrayModes; }
 211     bool* addressOfMayStoreToHole() { return &m_mayStoreToHole; }
 212
 213     void setOutOfBounds() { m_outOfBounds = true; }
 214     bool* addressOfOutOfBounds() { return &m_outOfBounds; }
 215
 216     void observeStructure(Structure* structure)
 217     {
 218         m_lastSeenStructureID = structure->id();
 219     }
 220
 221     void computeUpdatedPrediction(const ConcurrentJITLocker&, CodeBlock*);
 222     void computeUpdatedPrediction(const ConcurrentJITLocker&, CodeBlock*, Structure* lastSeenStructure);
 223
 224     ArrayModes observedArrayModes(const ConcurrentJITLocker&) const { return m_observedArrayModes; }
 225     bool mayInterceptIndexedAccesses(const ConcurrentJITLocker&) const { return m_mayInterceptIndexedAccesses; }
 226
 227     bool mayStoreToHole(const ConcurrentJITLocker&) const { return m_mayStoreToHole; }
 228     bool outOfBounds(const ConcurrentJITLocker&) const { return m_outOfBounds; }
 229
 230     bool usesOriginalArrayStructures(const ConcurrentJITLocker&) const { return m_usesOriginalArrayStructures; }
 231
 232     CString briefDescription(const ConcurrentJITLocker&, CodeBlock*);
 233     CString briefDescriptionWithoutUpdating(const ConcurrentJITLocker&);
 234
 235 private:
 236     friend class LLIntOffsetsExtractor;
 237
 238     static Structure* polymorphicStructure() { return static_cast<Structure*>(reinterpret_cast<void*>(1)); }
 239
 240     unsigned m_bytecodeOffset;
 241     StructureID m_lastSeenStructureID;
 242     bool m_mayStoreToHole; // This flag may become overloaded to indicate other special cases that were encountered during array access, as it depends on indexing type. Since we currently have basically just one indexing type (two variants of ArrayStorage), this flag for now just means exactly what its name implies.
 243     bool m_outOfBounds;
 244     bool m_mayInterceptIndexedAccesses : 1;
 245     bool m_usesOriginalArrayStructures : 1;
 246     bool m_didPerformFirstRunPruning : 1;
 247     ArrayModes m_observedArrayModes;
 248 };
 249
 250 typedef SegmentedVector<ArrayProfile, 4> ArrayProfileVector;
 251
 252 } // namespace JSC
 253
 254 #endif // ArrayProfile_h
 255