runtime/ButterflyInlines.h

   1 /*
   2  * Copyright (C) 2012 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 ButterflyInlines_h
  27 #define ButterflyInlines_h
  28
  29 #include "ArrayStorage.h"
  30 #include "Butterfly.h"
  31 #include "CopiedSpaceInlines.h"
  32 #include "CopyVisitor.h"
  33 #include "VM.h"
  34 #include "Structure.h"
  35
  36 namespace JSC {
  37
  38 inline Butterfly* Butterfly::createUninitialized(VM& vm, JSCell* intendedOwner, size_t preCapacity, size_t propertyCapacity, bool hasIndexingHeader, size_t indexingPayloadSizeInBytes)
  39 {
  40     void* temp;
  41     size_t size = totalSize(preCapacity, propertyCapacity, hasIndexingHeader, indexingPayloadSizeInBytes);
  42     RELEASE_ASSERT(vm.heap.tryAllocateStorage(intendedOwner, size, &temp));
  43     Butterfly* result = fromBase(temp, preCapacity, propertyCapacity);
  44     return result;
  45 }
  46
  47 inline Butterfly* Butterfly::create(VM& vm, JSCell* intendedOwner, size_t preCapacity, size_t propertyCapacity, bool hasIndexingHeader, const IndexingHeader& indexingHeader, size_t indexingPayloadSizeInBytes)
  48 {
  49     Butterfly* result = createUninitialized(
  50         vm, intendedOwner, preCapacity, propertyCapacity, hasIndexingHeader,
  51         indexingPayloadSizeInBytes);
  52     if (hasIndexingHeader)
  53         *result->indexingHeader() = indexingHeader;
  54     return result;
  55 }
  56
  57 inline Butterfly* Butterfly::create(VM& vm, JSCell* intendedOwner, Structure* structure)
  58 {
  59     return create(
  60         vm, intendedOwner, 0, structure->outOfLineCapacity(),
  61         structure->hasIndexingHeader(intendedOwner), IndexingHeader(), 0);
  62 }
  63
  64 inline Butterfly* Butterfly::createUninitializedDuringCollection(CopyVisitor& visitor, size_t preCapacity, size_t propertyCapacity, bool hasIndexingHeader, size_t indexingPayloadSizeInBytes)
  65 {
  66     size_t size = totalSize(preCapacity, propertyCapacity, hasIndexingHeader, indexingPayloadSizeInBytes);
  67     Butterfly* result = fromBase(
  68         visitor.allocateNewSpace(size),
  69         preCapacity, propertyCapacity);
  70     return result;
  71 }
  72
  73 inline void* Butterfly::base(Structure* structure)
  74 {
  75     return base(indexingHeader()->preCapacity(structure), structure->outOfLineCapacity());
  76 }
  77
  78 inline Butterfly* Butterfly::createOrGrowPropertyStorage(
  79     Butterfly* oldButterfly, VM& vm, JSCell* intendedOwner, Structure* structure, size_t oldPropertyCapacity, size_t newPropertyCapacity)
  80 {
  81     RELEASE_ASSERT(newPropertyCapacity > oldPropertyCapacity);
  82     if (!oldButterfly)
  83         return create(vm, intendedOwner, 0, newPropertyCapacity, false, IndexingHeader(), 0);
  84
  85     size_t preCapacity = oldButterfly->indexingHeader()->preCapacity(structure);
  86     size_t indexingPayloadSizeInBytes = oldButterfly->indexingHeader()->indexingPayloadSizeInBytes(structure);
  87     bool hasIndexingHeader = structure->hasIndexingHeader(intendedOwner);
  88     Butterfly* result = createUninitialized(
  89         vm, intendedOwner, preCapacity, newPropertyCapacity, hasIndexingHeader, indexingPayloadSizeInBytes);
  90     memcpy(
  91         result->propertyStorage() - oldPropertyCapacity,
  92         oldButterfly->propertyStorage() - oldPropertyCapacity,
  93         totalSize(0, oldPropertyCapacity, hasIndexingHeader, indexingPayloadSizeInBytes));
  94     return result;
  95 }
  96
  97 inline Butterfly* Butterfly::createOrGrowArrayRight(
  98     Butterfly* oldButterfly, VM& vm, JSCell* intendedOwner, Structure* oldStructure,
  99     size_t propertyCapacity, bool hadIndexingHeader, size_t oldIndexingPayloadSizeInBytes,
 100     size_t newIndexingPayloadSizeInBytes)
 101 {
 102     if (!oldButterfly) {
 103         return create(
 104             vm, intendedOwner, 0, propertyCapacity, true, IndexingHeader(),
 105             newIndexingPayloadSizeInBytes);
 106     }
 107     return oldButterfly->growArrayRight(
 108         vm, intendedOwner, oldStructure, propertyCapacity, hadIndexingHeader,
 109         oldIndexingPayloadSizeInBytes, newIndexingPayloadSizeInBytes);
 110 }
 111
 112 inline Butterfly* Butterfly::growArrayRight(
 113     VM& vm, JSCell* intendedOwner, Structure* oldStructure, size_t propertyCapacity,
 114     bool hadIndexingHeader, size_t oldIndexingPayloadSizeInBytes,
 115     size_t newIndexingPayloadSizeInBytes)
 116 {
 117     ASSERT_UNUSED(oldStructure, !indexingHeader()->preCapacity(oldStructure));
 118     ASSERT_UNUSED(oldStructure, hadIndexingHeader == oldStructure->hasIndexingHeader(intendedOwner));
 119     void* theBase = base(0, propertyCapacity);
 120     size_t oldSize = totalSize(0, propertyCapacity, hadIndexingHeader, oldIndexingPayloadSizeInBytes);
 121     size_t newSize = totalSize(0, propertyCapacity, true, newIndexingPayloadSizeInBytes);
 122     if (!vm.heap.tryReallocateStorage(intendedOwner, &theBase, oldSize, newSize))
 123         return 0;
 124     return fromBase(theBase, 0, propertyCapacity);
 125 }
 126
 127 inline Butterfly* Butterfly::growArrayRight(
 128     VM& vm, JSCell* intendedOwner, Structure* oldStructure,
 129     size_t newIndexingPayloadSizeInBytes)
 130 {
 131     return growArrayRight(
 132         vm, intendedOwner, oldStructure, oldStructure->outOfLineCapacity(),
 133         oldStructure->hasIndexingHeader(intendedOwner),
 134         indexingHeader()->indexingPayloadSizeInBytes(oldStructure),
 135         newIndexingPayloadSizeInBytes);
 136 }
 137
 138 inline Butterfly* Butterfly::resizeArray(
 139     VM& vm, JSCell* intendedOwner, size_t propertyCapacity, bool oldHasIndexingHeader,
 140     size_t oldIndexingPayloadSizeInBytes, size_t newPreCapacity, bool newHasIndexingHeader,
 141     size_t newIndexingPayloadSizeInBytes)
 142 {
 143     Butterfly* result = createUninitialized(
 144         vm, intendedOwner, newPreCapacity, propertyCapacity, newHasIndexingHeader,
 145         newIndexingPayloadSizeInBytes);
 146     // FIXME: This could be made much more efficient if we used the property size,
 147     // not the capacity.
 148     void* to = result->propertyStorage() - propertyCapacity;
 149     void* from = propertyStorage() - propertyCapacity;
 150     size_t size = std::min(
 151         totalSize(0, propertyCapacity, oldHasIndexingHeader, oldIndexingPayloadSizeInBytes),
 152         totalSize(0, propertyCapacity, newHasIndexingHeader, newIndexingPayloadSizeInBytes));
 153     memcpy(to, from, size);
 154     return result;
 155 }
 156
 157 inline Butterfly* Butterfly::resizeArray(
 158     VM& vm, JSCell* intendedOwner, Structure* structure, size_t newPreCapacity,
 159     size_t newIndexingPayloadSizeInBytes)
 160 {
 161     bool hasIndexingHeader = structure->hasIndexingHeader(intendedOwner);
 162     return resizeArray(
 163         vm, intendedOwner, structure->outOfLineCapacity(), hasIndexingHeader,
 164         indexingHeader()->indexingPayloadSizeInBytes(structure), newPreCapacity,
 165         hasIndexingHeader, newIndexingPayloadSizeInBytes);
 166 }
 167
 168 inline Butterfly* Butterfly::unshift(Structure* structure, size_t numberOfSlots)
 169 {
 170     ASSERT(hasAnyArrayStorage(structure->indexingType()));
 171     ASSERT(numberOfSlots <= indexingHeader()->preCapacity(structure));
 172     unsigned propertyCapacity = structure->outOfLineCapacity();
 173     // FIXME: It would probably be wise to rewrite this as a loop since (1) we know in which
 174     // direction we're moving memory so we don't need the extra check of memmove and (2) we're
 175     // moving a small amount of memory in the common case so the throughput of memmove won't
 176     // amortize the overhead of calling it. And no, we cannot rely on the C++ compiler to
 177     // inline memmove (particularly since the size argument is likely to be variable), nor can
 178     // we rely on the compiler to recognize the ordering of the pointer arguments (since
 179     // propertyCapacity is variable and could cause wrap-around as far as the compiler knows).
 180     memmove(
 181         propertyStorage() - numberOfSlots - propertyCapacity,
 182         propertyStorage() - propertyCapacity,
 183         sizeof(EncodedJSValue) * propertyCapacity + sizeof(IndexingHeader) + ArrayStorage::sizeFor(0));
 184     return IndexingHeader::fromEndOf(propertyStorage() - numberOfSlots)->butterfly();
 185 }
 186
 187 inline Butterfly* Butterfly::shift(Structure* structure, size_t numberOfSlots)
 188 {
 189     ASSERT(hasAnyArrayStorage(structure->indexingType()));
 190     unsigned propertyCapacity = structure->outOfLineCapacity();
 191     // FIXME: See comment in unshift(), above.
 192     memmove(
 193         propertyStorage() - propertyCapacity + numberOfSlots,
 194         propertyStorage() - propertyCapacity,
 195         sizeof(EncodedJSValue) * propertyCapacity + sizeof(IndexingHeader) + ArrayStorage::sizeFor(0));
 196     return IndexingHeader::fromEndOf(propertyStorage() + numberOfSlots)->butterfly();
 197 }
 198
 199 } // namespace JSC
 200
 201 #endif // ButterflyInlines_h
 202