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