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      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/WTF.h"
     42 
     43 #include <string.h>
     44 
     45 namespace WTF {
     46 
     47 class DefaultAllocatorDummyVisitor;
     48 
     49 class DefaultAllocatorQuantizer {
     50 public:
     51     template<typename T>
     52     static size_t quantizedSize(size_t count)
     53     {
     54         RELEASE_ASSERT(count <= kMaxUnquantizedAllocation / sizeof(T));
     55         return partitionAllocActualSize(Partitions::getBufferPartition(), count * sizeof(T));
     56     }
     57     static const size_t kMaxUnquantizedAllocation = kGenericMaxDirectMapped;
     58 };
     59 
     60 class DefaultAllocator {
     61 public:
     62     typedef DefaultAllocatorQuantizer Quantizer;
     63     typedef DefaultAllocatorDummyVisitor Visitor;
     64     static const bool isGarbageCollected = false;
     65     template<typename T, typename Traits>
     66     struct VectorBackingHelper {
     67         typedef void Type;
     68     };
     69     template<typename T>
     70     struct HashTableBackingHelper {
     71         typedef void Type;
     72     };
     73     template <typename Return, typename Metadata>
     74     static Return backingMalloc(size_t size)
     75     {
     76         return reinterpret_cast<Return>(backingAllocate(size));
     77     }
     78     template <typename Return, typename Metadata>
     79     static Return zeroedBackingMalloc(size_t size)
     80     {
     81         void* result = backingAllocate(size);
     82         memset(result, 0, size);
     83         return reinterpret_cast<Return>(result);
     84     }
     85     template <typename Return, typename Metadata>
     86     static Return malloc(size_t size)
     87     {
     88         return reinterpret_cast<Return>(fastMalloc(size));
     89     }
     90     WTF_EXPORT static void backingFree(void* address);
     91     static void free(void* address)
     92     {
     93         fastFree(address);
     94     }
     95     template<typename T>
     96     static void* newArray(size_t bytes)
     97     {
     98         return malloc<void*, void>(bytes);
     99     }
    100     static void
    101     deleteArray(void* ptr)
    102     {
    103         free(ptr); // Not the system free, the one from this class.
    104     }
    105 
    106     static void markNoTracing(...)
    107     {
    108         ASSERT_NOT_REACHED();
    109     }
    110 
    111     static void registerWeakMembers(...)
    112     {
    113         ASSERT_NOT_REACHED();
    114     }
    115 
    116     template<typename T, typename Traits>
    117     static void trace(...)
    118     {
    119         ASSERT_NOT_REACHED();
    120     }
    121 
    122     template<typename T>
    123     struct OtherType {
    124         typedef T* Type;
    125     };
    126 
    127     template<typename T>
    128     static T& getOther(T* other)
    129     {
    130         return *other;
    131     }
    132 
    133 private:
    134     WTF_EXPORT static void* backingAllocate(size_t);
    135 };
    136 
    137 // The Windows compiler seems to be very eager to instantiate things it won't
    138 // need, so unless we have this class we get compile errors.
    139 class DefaultAllocatorDummyVisitor {
    140 public:
    141     template<typename T> inline bool isAlive(T obj)
    142     {
    143         ASSERT_NOT_REACHED();
    144         return false;
    145     }
    146 };
    147 
    148 } // namespace WTF
    149 
    150 #define WTF_USE_ALLOCATOR(ClassName, Allocator) \
    151 public: \
    152     void* operator new(size_t size) \
    153     { \
    154         return Allocator::template malloc<void*, ClassName>(size); \
    155     } \
    156     void operator delete(void* p) { Allocator::free(p); } \
    157     void* operator new[](size_t size) { return Allocator::template newArray<ClassName>(size); } \
    158     void operator delete[](void* p) { Allocator::deleteArray(p); } \
    159     void* operator new(size_t, NotNullTag, void* location) \
    160     { \
    161         ASSERT(location); \
    162         return location; \
    163     } \
    164 private: \
    165 typedef int __thisIsHereToForceASemicolonAfterThisMacro
    166 
    167 using WTF::DefaultAllocator;
    168 
    169 #endif // WTF_DefaultAllocator_h
    170