third_party/WebKit/Source/wtf/DefaultAllocator.h

   1 /*
   2  * Copyright (C) 2013 Google 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 are
   6  * met:
   7  *
   8  *     * Redistributions of source code must retain the above copyright
   9  * notice, this list of conditions and the following disclaimer.
  10  *     * Redistributions in binary form must reproduce the above
  11  * copyright notice, this list of conditions and the following disclaimer
  12  * in the documentation and/or other materials provided with the
  13  * distribution.
  14  *     * Neither the name of Google Inc. nor the names of its
  15  * contributors may be used to endorse or promote products derived from
  16  * this software without specific prior written permission.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  22  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  23  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  24  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  29  */
  30
  31 #ifndef WTF_DefaultAllocator_h
  32 #define WTF_DefaultAllocator_h
  33
  34 // This is the allocator that is used for allocations that are not on the
  35 // traced, garbage collected heap. It uses FastMalloc for collections,
  36 // but uses the partition allocator for the backing store of the collections.
  37
  38 #include "wtf/Assertions.h"
  39 #include "wtf/FastAllocBase.h"
  40 #include "wtf/PartitionAlloc.h"
  41 #include "wtf/Partitions.h"
  42
  43 #include <string.h>
  44
  45 namespace WTF {
  46
  47 class DefaultAllocatorDummyVisitor;
  48
  49 class WTF_EXPORT DefaultAllocator {
  50 public:
  51     typedef DefaultAllocatorDummyVisitor Visitor;
  52     static const bool isGarbageCollected = false;
  53
  54     template<typename T>
  55     static size_t quantizedSize(size_t count)
  56     {
  57         RELEASE_ASSERT(count <= kGenericMaxDirectMapped / sizeof(T));
  58         return partitionAllocActualSize(Partitions::bufferPartition(), count * sizeof(T));
  59     }
  60     template <typename T>
  61     static T* allocateVectorBacking(size_t size)
  62     {
  63         return reinterpret_cast<T*>(allocateBacking(size));
  64     }
  65     template <typename T>
  66     static T* allocateExpandedVectorBacking(size_t size)
  67     {
  68         return reinterpret_cast<T*>(allocateBacking(size));
  69     }
  70     static void freeVectorBacking(void* address);
  71     static inline bool expandVectorBacking(void*, size_t)
  72     {
  73         return false;
  74     }
  75     static inline bool shrinkVectorBacking(void* address, size_t quantizedCurrentSize, size_t quantizedShrunkSize)
  76     {
  77         // Optimization: if we're downsizing inside the same allocator bucket,
  78         // we can skip reallocation.
  79         return quantizedCurrentSize == quantizedShrunkSize;
  80     }
  81     template <typename T>
  82     static T* allocateInlineVectorBacking(size_t size) { return allocateVectorBacking<T>(size); }
  83     static inline void freeInlineVectorBacking(void* address) { freeVectorBacking(address); }
  84     static inline bool expandInlineVectorBacking(void*, size_t) { return false; }
  85     static inline bool shrinkInlineVectorBacking(void* address, size_t quantizedCurrentSize, size_t quantizedShrunkSize) { return shrinkVectorBacking(address, quantizedCurrentSize, quantizedShrunkSize); }
  86
  87     template <typename T, typename HashTable>
  88     static T* allocateHashTableBacking(size_t size)
  89     {
  90         return reinterpret_cast<T*>(allocateBacking(size));
  91     }
  92     template <typename T, typename HashTable>
  93     static T* allocateZeroedHashTableBacking(size_t size)
  94     {
  95         void* result = allocateBacking(size);
  96         memset(result, 0, size);
  97         return reinterpret_cast<T*>(result);
  98     }
  99     static void freeHashTableBacking(void* address);
 100
 101     template <typename Return, typename Metadata>
 102     static Return malloc(size_t size)
 103     {
 104         return reinterpret_cast<Return>(fastMalloc(size));
 105     }
 106
 107     static inline bool expandHashTableBacking(void*, size_t)
 108     {
 109         return false;
 110     }
 111     static void free(void* address)
 112     {
 113         fastFree(address);
 114     }
 115     template<typename T>
 116     static void* newArray(size_t bytes)
 117     {
 118         return malloc<void*, void>(bytes);
 119     }
 120     static void
 121     deleteArray(void* ptr)
 122     {
 123         free(ptr); // Not the system free, the one from this class.
 124     }
 125
 126     static bool isAllocationAllowed() { return true; }
 127     template<typename T>
 128     static bool isHeapObjectAlive(T* object)
 129     {
 130         ASSERT_NOT_REACHED();
 131         return false;
 132     }
 133
 134     static void markNoTracing(...)
 135     {
 136         ASSERT_NOT_REACHED();
 137     }
 138
 139     static void registerDelayedMarkNoTracing(...)
 140     {
 141         ASSERT_NOT_REACHED();
 142     }
 143
 144     static void registerWeakMembers(...)
 145     {
 146         ASSERT_NOT_REACHED();
 147     }
 148
 149     static void registerWeakTable(...)
 150     {
 151         ASSERT_NOT_REACHED();
 152     }
 153
 154 #if ENABLE(ASSERT)
 155     static bool weakTableRegistered(...)
 156     {
 157         ASSERT_NOT_REACHED();
 158         return false;
 159     }
 160 #endif
 161
 162     template<typename T, typename Traits>
 163     static void trace(...)
 164     {
 165         ASSERT_NOT_REACHED();
 166     }
 167
 168     template<typename T>
 169     struct OtherType {
 170         typedef T* Type;
 171     };
 172
 173     template<typename T>
 174     static T& getOther(T* other)
 175     {
 176         return *other;
 177     }
 178
 179     static void enterNoAllocationScope() { }
 180     static void leaveNoAllocationScope() { }
 181     static void enterGCForbiddenScope() { }
 182     static void leaveGCForbiddenScope() { }
 183
 184 private:
 185     static void* allocateBacking(size_t);
 186 };
 187
 188 // The Windows compiler seems to be very eager to instantiate things it won't
 189 // need, so unless we have this class we get compile errors.
 190 class DefaultAllocatorDummyVisitor {
 191 public:
 192     template<typename T> inline bool isHeapObjectAlive(T obj)
 193     {
 194         ASSERT_NOT_REACHED();
 195         return false;
 196     }
 197 };
 198
 199 } // namespace WTF
 200
 201 #define WTF_USE_ALLOCATOR(ClassName, Allocator) \
 202 public: \
 203     void* operator new(size_t size) \
 204     { \
 205         return Allocator::template malloc<void*, ClassName>(size); \
 206     } \
 207     void operator delete(void* p) { Allocator::free(p); } \
 208     void* operator new[](size_t size) { return Allocator::template newArray<ClassName>(size); } \
 209     void operator delete[](void* p) { Allocator::deleteArray(p); } \
 210     void* operator new(size_t, NotNullTag, void* location) \
 211     { \
 212         ASSERT(location); \
 213         return location; \
 214     } \
 215 private: \
 216 typedef int __thisIsHereToForceASemicolonAfterThisMacro
 217
 218 using WTF::DefaultAllocator;
 219
 220 #endif // WTF_DefaultAllocator_h