Move Source/WTF/wtf to Source/wtf

Source/WTF/wtf/FastMalloc.cpp

-// Copyright (c) 2005, 2007, Google Inc.
-// All rights reserved.
-// Copyright (C) 2005, 2006, 2007, 2008, 2009, 2011 Apple Inc. All rights reserved.
-// 
-// Redistribution and use in source and binary forms, with or without
-// modification, are permitted provided that the following conditions are
-// met:
-// 
-//     * Redistributions of source code must retain the above copyright
-// notice, this list of conditions and the following disclaimer.
-//     * Redistributions in binary form must reproduce the above
-// copyright notice, this list of conditions and the following disclaimer
-// in the documentation and/or other materials provided with the
-// distribution.
-//     * Neither the name of Google Inc. nor the names of its
-// contributors may be used to endorse or promote products derived from
-// this software without specific prior written permission.
-// 
-// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-
-// ---
-// Author: Sanjay Ghemawat <opensource@google.com>
-//
-// A malloc that uses a per-thread cache to satisfy small malloc requests.
-// (The time for malloc/free of a small object drops from 300 ns to 50 ns.)
-//
-// See doc/tcmalloc.html for a high-level
-// description of how this malloc works.
-//
-// SYNCHRONIZATION
-//  1. The thread-specific lists are accessed without acquiring any locks.
-//     This is safe because each such list is only accessed by one thread.
-//  2. We have a lock per central free-list, and hold it while manipulating
-//     the central free list for a particular size.
-//  3. The central page allocator is protected by "pageheap_lock".
-//  4. The pagemap (which maps from page-number to descriptor),
-//     can be read without holding any locks, and written while holding
-//     the "pageheap_lock".
-//  5. To improve performance, a subset of the information one can get
-//     from the pagemap is cached in a data structure, pagemap_cache_,
-//     that atomically reads and writes its entries.  This cache can be
-//     read and written without locking.
-//
-//     This multi-threaded access to the pagemap is safe for fairly
-//     subtle reasons.  We basically assume that when an object X is
-//     allocated by thread A and deallocated by thread B, there must
-//     have been appropriate synchronization in the handoff of object
-//     X from thread A to thread B.  The same logic applies to pagemap_cache_.
-//
-// THE PAGEID-TO-SIZECLASS CACHE
-// Hot PageID-to-sizeclass mappings are held by pagemap_cache_.  If this cache
-// returns 0 for a particular PageID then that means "no information," not that
-// the sizeclass is 0.  The cache may have stale information for pages that do
-// not hold the beginning of any free()'able object.  Staleness is eliminated
-// in Populate() for pages with sizeclass > 0 objects, and in do_malloc() and
-// do_memalign() for all other relevant pages.
-//
-// TODO: Bias reclamation to larger addresses
-// TODO: implement mallinfo/mallopt
-// TODO: Better testing
-//
-// 9/28/2003 (new page-level allocator replaces ptmalloc2):
-// * malloc/free of small objects goes from ~300 ns to ~50 ns.
-// * allocation of a reasonably complicated struct
-//   goes from about 1100 ns to about 300 ns.
-
-#include "config.h"
-#include "FastMalloc.h"
-
-#include "Assertions.h"
-
-#include <limits>
-#if OS(WINDOWS)
-#include <windows.h>
-#else
-#include <pthread.h>
-#endif
-#include <string.h>
-#include <wtf/StdLibExtras.h>
-#include <wtf/UnusedParam.h>
-
-#ifndef NO_TCMALLOC_SAMPLES
-#ifdef WTF_CHANGES
-#define NO_TCMALLOC_SAMPLES
-#endif
-#endif
-
-#if !USE(SYSTEM_MALLOC) && defined(NDEBUG)
-#define FORCE_SYSTEM_MALLOC 0
-#else
-#define FORCE_SYSTEM_MALLOC 1
-#endif
-
-// Harden the pointers stored in the TCMalloc linked lists
-#if COMPILER(GCC)
-#define ENABLE_TCMALLOC_HARDENING 1
-#endif
-
-// Use a background thread to periodically scavenge memory to release back to the system
-#define USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY 1
-
-#ifndef NDEBUG
-namespace WTF {
-
-#if OS(WINDOWS)
-
-// TLS_OUT_OF_INDEXES is not defined on WinCE.
-#ifndef TLS_OUT_OF_INDEXES
-#define TLS_OUT_OF_INDEXES 0xffffffff
-#endif
-
-static DWORD isForibiddenTlsIndex = TLS_OUT_OF_INDEXES;
-static const LPVOID kTlsAllowValue = reinterpret_cast<LPVOID>(0); // Must be zero.
-static const LPVOID kTlsForbiddenValue = reinterpret_cast<LPVOID>(1);
-
-#if !ASSERT_DISABLED
-static bool isForbidden()
-{
-    // By default, fastMalloc is allowed so we don't allocate the
-    // tls index unless we're asked to make it forbidden. If TlsSetValue
-    // has not been called on a thread, the value returned by TlsGetValue is 0.
-    return (isForibiddenTlsIndex != TLS_OUT_OF_INDEXES) && (TlsGetValue(isForibiddenTlsIndex) == kTlsForbiddenValue);
-}
-#endif
-
-void fastMallocForbid()
-{
-    if (isForibiddenTlsIndex == TLS_OUT_OF_INDEXES)
-        isForibiddenTlsIndex = TlsAlloc(); // a little racey, but close enough for debug only
-    TlsSetValue(isForibiddenTlsIndex, kTlsForbiddenValue);
-}
-
-void fastMallocAllow()
-{
-    if (isForibiddenTlsIndex == TLS_OUT_OF_INDEXES)
-        return;
-    TlsSetValue(isForibiddenTlsIndex, kTlsAllowValue);
-}
-
-#else // !OS(WINDOWS)
-
-static pthread_key_t isForbiddenKey;
-static pthread_once_t isForbiddenKeyOnce = PTHREAD_ONCE_INIT;
-static void initializeIsForbiddenKey()
-{
-  pthread_key_create(&isForbiddenKey, 0);
-}
-
-#if !ASSERT_DISABLED
-static bool isForbidden()
-{
-    pthread_once(&isForbiddenKeyOnce, initializeIsForbiddenKey);
-    return !!pthread_getspecific(isForbiddenKey);
-}
-#endif
-
-void fastMallocForbid()
-{
-    pthread_once(&isForbiddenKeyOnce, initializeIsForbiddenKey);
-    pthread_setspecific(isForbiddenKey, &isForbiddenKey);
-}
-
-void fastMallocAllow()
-{
-    pthread_once(&isForbiddenKeyOnce, initializeIsForbiddenKey);
-    pthread_setspecific(isForbiddenKey, 0);
-}
-#endif // OS(WINDOWS)
-
-} // namespace WTF
-#endif // NDEBUG
-
-namespace WTF {
-
-
-namespace Internal {
-#if !ENABLE(WTF_MALLOC_VALIDATION)
-WTF_EXPORT_PRIVATE void fastMallocMatchFailed(void*);
-#else
-COMPILE_ASSERT(((sizeof(ValidationHeader) % sizeof(AllocAlignmentInteger)) == 0), ValidationHeader_must_produce_correct_alignment);
-#endif
-
-NO_RETURN_DUE_TO_CRASH void fastMallocMatchFailed(void*)
-{
-    CRASH();
-}
-
-} // namespace Internal
-
-
-void* fastZeroedMalloc(size_t n) 
-{
-    void* result = fastMalloc(n);
-    memset(result, 0, n);
-    return result;
-}
-
-char* fastStrDup(const char* src)
-{
-    size_t len = strlen(src) + 1;
-    char* dup = static_cast<char*>(fastMalloc(len));
-    memcpy(dup, src, len);
-    return dup;
-}
-
-TryMallocReturnValue tryFastZeroedMalloc(size_t n) 
-{
-    void* result;
-    if (!tryFastMalloc(n).getValue(result))
-        return 0;
-    memset(result, 0, n);
-    return result;
-}
-
-} // namespace WTF
-
-#if FORCE_SYSTEM_MALLOC
-
-#if OS(DARWIN)
-#include <malloc/malloc.h>
-#elif OS(WINDOWS)
-#include <malloc.h>
-#endif
-
-namespace WTF {
-
-size_t fastMallocGoodSize(size_t bytes)
-{
-#if OS(DARWIN)
-    return malloc_good_size(bytes);
-#else
-    return bytes;
-#endif
-}
-
-TryMallocReturnValue tryFastMalloc(size_t n) 
-{
-    ASSERT(!isForbidden());
-
-#if ENABLE(WTF_MALLOC_VALIDATION)
-    if (std::numeric_limits<size_t>::max() - Internal::ValidationBufferSize <= n)  // If overflow would occur...
-        return 0;
-
-    void* result = malloc(n + Internal::ValidationBufferSize);
-    if (!result)
-        return 0;
-    Internal::ValidationHeader* header = static_cast<Internal::ValidationHeader*>(result);
-    header->m_size = n;
-    header->m_type = Internal::AllocTypeMalloc;
-    header->m_prefix = static_cast<unsigned>(Internal::ValidationPrefix);
-    result = header + 1;
-    *Internal::fastMallocValidationSuffix(result) = Internal::ValidationSuffix;
-    fastMallocValidate(result);
-    return result;
-#else
-    return malloc(n);
-#endif
-}
-
-void* fastMalloc(size_t n) 
-{
-    ASSERT(!isForbidden());
-
-#if ENABLE(WTF_MALLOC_VALIDATION)
-    TryMallocReturnValue returnValue = tryFastMalloc(n);
-    void* result;
-    if (!returnValue.getValue(result))
-        CRASH();
-#else
-    void* result = malloc(n);
-#endif
-
-    ASSERT(result);  // We expect tcmalloc underneath, which would crash instead of getting here.
-
-    return result;
-}
-
-TryMallocReturnValue tryFastCalloc(size_t n_elements, size_t element_size)
-{
-    ASSERT(!isForbidden());
-
-#if ENABLE(WTF_MALLOC_VALIDATION)
-    size_t totalBytes = n_elements * element_size;
-    if (n_elements > 1 && element_size && (totalBytes / element_size) != n_elements)
-        return 0;
-
-    TryMallocReturnValue returnValue = tryFastMalloc(totalBytes);
-    void* result;
-    if (!returnValue.getValue(result))
-        return 0;
-    memset(result, 0, totalBytes);
-    fastMallocValidate(result);
-    return result;
-#else
-    return calloc(n_elements, element_size);
-#endif
-}
-
-void* fastCalloc(size_t n_elements, size_t element_size)
-{
-    ASSERT(!isForbidden());
-
-#if ENABLE(WTF_MALLOC_VALIDATION)
-    TryMallocReturnValue returnValue = tryFastCalloc(n_elements, element_size);
-    void* result;
-    if (!returnValue.getValue(result))
-        CRASH();
-#else
-    void* result = calloc(n_elements, element_size);
-#endif
-
-    ASSERT(result);  // We expect tcmalloc underneath, which would crash instead of getting here.
-
-    return result;
-}
-
-void fastFree(void* p)
-{
-    ASSERT(!isForbidden());
-
-#if ENABLE(WTF_MALLOC_VALIDATION)
-    if (!p)
-        return;
-    
-    fastMallocMatchValidateFree(p, Internal::AllocTypeMalloc);
-    Internal::ValidationHeader* header = Internal::fastMallocValidationHeader(p);
-    memset(p, 0xCC, header->m_size);
-    free(header);
-#else
-    free(p);
-#endif
-}
-
-TryMallocReturnValue tryFastRealloc(void* p, size_t n)
-{
-    ASSERT(!isForbidden());
-
-#if ENABLE(WTF_MALLOC_VALIDATION)
-    if (p) {
-        if (std::numeric_limits<size_t>::max() - Internal::ValidationBufferSize <= n)  // If overflow would occur...
-            return 0;
-        fastMallocValidate(p);
-        Internal::ValidationHeader* result = static_cast<Internal::ValidationHeader*>(realloc(Internal::fastMallocValidationHeader(p), n + Internal::ValidationBufferSize));
-        if (!result)
-            return 0;
-        result->m_size = n;
-        result = result + 1;
-        *fastMallocValidationSuffix(result) = Internal::ValidationSuffix;
-        fastMallocValidate(result);
-        return result;
-    } else {
-        return fastMalloc(n);
-    }
-#else
-    return realloc(p, n);
-#endif
-}
-
-void* fastRealloc(void* p, size_t n)
-{
-    ASSERT(!isForbidden());
-
-#if ENABLE(WTF_MALLOC_VALIDATION)
-    TryMallocReturnValue returnValue = tryFastRealloc(p, n);
-    void* result;
-    if (!returnValue.getValue(result))
-        CRASH();
-#else
-    void* result = realloc(p, n);
-#endif
-
-    ASSERT(result);  // We expect tcmalloc underneath, which would crash instead of getting here.
-
-    return result;
-}
-
-void releaseFastMallocFreeMemory() { }
-    
-FastMallocStatistics fastMallocStatistics()
-{
-    FastMallocStatistics statistics = { 0, 0, 0 };
-    return statistics;
-}
-
-size_t fastMallocSize(const void* p)
-{
-#if ENABLE(WTF_MALLOC_VALIDATION)
-    return Internal::fastMallocValidationHeader(const_cast<void*>(p))->m_size;
-#elif OS(DARWIN)
-    return malloc_size(p);
-#elif OS(WINDOWS)
-    return _msize(const_cast<void*>(p));
-#else
-    UNUSED_PARAM(p);
-    return 1;
-#endif
-}
-
-} // namespace WTF
-
-#if OS(DARWIN)
-// This symbol is present in the JavaScriptCore exports file even when FastMalloc is disabled.
-// It will never be used in this case, so it's type and value are less interesting than its presence.
-extern "C" WTF_EXPORT_PRIVATE const int jscore_fastmalloc_introspection = 0;
-#endif
-
-#else // FORCE_SYSTEM_MALLOC
-
-#include "Compiler.h"
-#include "TCPackedCache.h"
-#include "TCPageMap.h"
-#include "TCSpinLock.h"
-#include "TCSystemAlloc.h"
-#include <algorithm>
-#include <pthread.h>
-#include <stdarg.h>
-#include <stddef.h>
-#include <stdint.h>
-#include <stdio.h>
-#if HAVE(ERRNO_H)
-#include <errno.h>
-#endif
-#if OS(UNIX)
-#include <unistd.h>
-#endif
-#if OS(WINDOWS)
-#ifndef WIN32_LEAN_AND_MEAN
-#define WIN32_LEAN_AND_MEAN
-#endif
-#include <windows.h>
-#endif
-
-#ifdef WTF_CHANGES
-
-#if OS(DARWIN)
-#include "MallocZoneSupport.h"
-#include <wtf/HashSet.h>
-#include <wtf/Vector.h>
-#endif
-
-#if HAVE(DISPATCH_H)
-#include <dispatch/dispatch.h>
-#endif
-
-#ifdef __has_include
-#if __has_include(<System/pthread_machdep.h>)
-
-#include <System/pthread_machdep.h>
-
-#if defined(__PTK_FRAMEWORK_JAVASCRIPTCORE_KEY0)
-#define WTF_USE_PTHREAD_GETSPECIFIC_DIRECT 1
-#endif
-
-#endif
-#endif
-
-#ifndef PRIuS
-#define PRIuS "zu"
-#endif
-
-// Calling pthread_getspecific through a global function pointer is faster than a normal
-// call to the function on Mac OS X, and it's used in performance-critical code. So we
-// use a function pointer. But that's not necessarily faster on other platforms, and we had
-// problems with this technique on Windows, so we'll do this only on Mac OS X.
-#if OS(DARWIN)
-#if !USE(PTHREAD_GETSPECIFIC_DIRECT)
-static void* (*pthread_getspecific_function_pointer)(pthread_key_t) = pthread_getspecific;
-#define pthread_getspecific(key) pthread_getspecific_function_pointer(key)
-#else
-#define pthread_getspecific(key) _pthread_getspecific_direct(key)
-#define pthread_setspecific(key, val) _pthread_setspecific_direct(key, (val))
-#endif
-#endif
-
-#define DEFINE_VARIABLE(type, name, value, meaning) \
-  namespace FLAG__namespace_do_not_use_directly_use_DECLARE_##type##_instead {  \
-  type FLAGS_##name(value);                                \
-  char FLAGS_no##name;                                                        \
-  }                                                                           \
-  using FLAG__namespace_do_not_use_directly_use_DECLARE_##type##_instead::FLAGS_##name
-  
-#define DEFINE_int64(name, value, meaning) \
-  DEFINE_VARIABLE(int64_t, name, value, meaning)
-  
-#define DEFINE_double(name, value, meaning) \
-  DEFINE_VARIABLE(double, name, value, meaning)
-
-namespace WTF {
-
-#define malloc fastMalloc
-#define calloc fastCalloc
-#define free fastFree
-#define realloc fastRealloc
-
-#define MESSAGE LOG_ERROR
-#define CHECK_CONDITION ASSERT
-
-static const char kLLHardeningMask = 0;
-template <unsigned> struct EntropySource;
-template <> struct EntropySource<4> {
-    static uint32_t value()
-    {
-#if OS(DARWIN)
-        return arc4random();
-#else
-        return static_cast<uint32_t>(static_cast<uintptr_t>(currentTime() * 10000) ^ reinterpret_cast<uintptr_t>(&kLLHardeningMask));
-#endif
-    }
-};
-
-template <> struct EntropySource<8> {
-    static uint64_t value()
-    {
-        return EntropySource<4>::value() | (static_cast<uint64_t>(EntropySource<4>::value()) << 32);
-    }
-};
-
-#if ENABLE(TCMALLOC_HARDENING)
-/*
- * To make it harder to exploit use-after free style exploits
- * we mask the addresses we put into our linked lists with the
- * address of kLLHardeningMask.  Due to ASLR the address of
- * kLLHardeningMask should be sufficiently randomized to make direct
- * freelist manipulation much more difficult.
- */
-enum {
-    MaskKeyShift = 13
-};
-
-static ALWAYS_INLINE uintptr_t internalEntropyValue() 
-{
-    static uintptr_t value = EntropySource<sizeof(uintptr_t)>::value() | 1;
-    ASSERT(value);
-    return value;
-}
-
-#define HARDENING_ENTROPY internalEntropyValue()
-#define ROTATE_VALUE(value, amount) (((value) >> (amount)) | ((value) << (sizeof(value) * 8 - (amount))))
-#define XOR_MASK_PTR_WITH_KEY(ptr, key, entropy) (reinterpret_cast<typeof(ptr)>(reinterpret_cast<uintptr_t>(ptr)^(ROTATE_VALUE(reinterpret_cast<uintptr_t>(key), MaskKeyShift)^entropy)))
-
-
-static ALWAYS_INLINE uint32_t freedObjectStartPoison()
-{
-    static uint32_t value = EntropySource<sizeof(uint32_t)>::value() | 1;
-    ASSERT(value);
-    return value;
-}
-
-static ALWAYS_INLINE uint32_t freedObjectEndPoison()
-{
-    static uint32_t value = EntropySource<sizeof(uint32_t)>::value() | 1;
-    ASSERT(value);
-    return value;
-}
-
-#define PTR_TO_UINT32(ptr) static_cast<uint32_t>(reinterpret_cast<uintptr_t>(ptr))
-#define END_POISON_INDEX(allocationSize) (((allocationSize) - sizeof(uint32_t)) / sizeof(uint32_t))
-#define POISON_ALLOCATION(allocation, allocationSize) do { \
-    ASSERT((allocationSize) >= 2 * sizeof(uint32_t)); \
-    reinterpret_cast<uint32_t*>(allocation)[0] = 0xbadbeef1; \
-    reinterpret_cast<uint32_t*>(allocation)[1] = 0xbadbeef3; \
-    if ((allocationSize) < 4 * sizeof(uint32_t)) \
-        break; \
-    reinterpret_cast<uint32_t*>(allocation)[2] = 0xbadbeef5; \
-    reinterpret_cast<uint32_t*>(allocation)[END_POISON_INDEX(allocationSize)] = 0xbadbeef7; \
-} while (false);
-
-#define POISON_DEALLOCATION_EXPLICIT(allocation, allocationSize, startPoison, endPoison) do { \
-    ASSERT((allocationSize) >= 2 * sizeof(uint32_t)); \
-    reinterpret_cast<uint32_t*>(allocation)[0] = 0xbadbeef9; \
-    reinterpret_cast<uint32_t*>(allocation)[1] = 0xbadbeefb; \
-    if ((allocationSize) < 4 * sizeof(uint32_t)) \
-        break; \
-    reinterpret_cast<uint32_t*>(allocation)[2] = (startPoison) ^ PTR_TO_UINT32(allocation); \
-    reinterpret_cast<uint32_t*>(allocation)[END_POISON_INDEX(allocationSize)] = (endPoison) ^ PTR_TO_UINT32(allocation); \
-} while (false)
-
-#define POISON_DEALLOCATION(allocation, allocationSize) \
-    POISON_DEALLOCATION_EXPLICIT(allocation, (allocationSize), freedObjectStartPoison(), freedObjectEndPoison())
-
-#define MAY_BE_POISONED(allocation, allocationSize) (((allocationSize) >= 4 * sizeof(uint32_t)) && ( \
-    (reinterpret_cast<uint32_t*>(allocation)[2] == (freedObjectStartPoison() ^ PTR_TO_UINT32(allocation))) || \
-    (reinterpret_cast<uint32_t*>(allocation)[END_POISON_INDEX(allocationSize)] == (freedObjectEndPoison() ^ PTR_TO_UINT32(allocation))) \
-))
-
-#define IS_DEFINITELY_POISONED(allocation, allocationSize) (((allocationSize) < 4 * sizeof(uint32_t)) || ( \
-    (reinterpret_cast<uint32_t*>(allocation)[2] == (freedObjectStartPoison() ^ PTR_TO_UINT32(allocation))) && \
-    (reinterpret_cast<uint32_t*>(allocation)[END_POISON_INDEX(allocationSize)] == (freedObjectEndPoison() ^ PTR_TO_UINT32(allocation))) \
-))
-
-#else
-
-#define POISON_ALLOCATION(allocation, allocationSize)
-#define POISON_DEALLOCATION(allocation, allocationSize)
-#define POISON_DEALLOCATION_EXPLICIT(allocation, allocationSize, startPoison, endPoison)
-#define MAY_BE_POISONED(allocation, allocationSize) (false)
-#define IS_DEFINITELY_POISONED(allocation, allocationSize) (true)
-#define XOR_MASK_PTR_WITH_KEY(ptr, key, entropy) (((void)entropy), ((void)key), ptr)
-
-#define HARDENING_ENTROPY 0
-
-#endif
-
-//-------------------------------------------------------------------
-// Configuration
-//-------------------------------------------------------------------
-
-// Not all possible combinations of the following parameters make
-// sense.  In particular, if kMaxSize increases, you may have to
-// increase kNumClasses as well.
-static const size_t kPageShift  = 12;
-static const size_t kPageSize   = 1 << kPageShift;
-static const size_t kMaxSize    = 8u * kPageSize;
-static const size_t kAlignShift = 3;
-static const size_t kAlignment  = 1 << kAlignShift;
-static const size_t kNumClasses = 68;
-
-// Allocates a big block of memory for the pagemap once we reach more than
-// 128MB
-static const size_t kPageMapBigAllocationThreshold = 128 << 20;
-
-// Minimum number of pages to fetch from system at a time.  Must be
-// significantly bigger than kPageSize to amortize system-call
-// overhead, and also to reduce external fragementation.  Also, we
-// should keep this value big because various incarnations of Linux
-// have small limits on the number of mmap() regions per
-// address-space.
-static const size_t kMinSystemAlloc = 1 << (20 - kPageShift);
-
-// Number of objects to move between a per-thread list and a central
-// list in one shot.  We want this to be not too small so we can
-// amortize the lock overhead for accessing the central list.  Making
-// it too big may temporarily cause unnecessary memory wastage in the
-// per-thread free list until the scavenger cleans up the list.
-static int num_objects_to_move[kNumClasses];
-
-// Maximum length we allow a per-thread free-list to have before we
-// move objects from it into the corresponding central free-list.  We
-// want this big to avoid locking the central free-list too often.  It
-// should not hurt to make this list somewhat big because the
-// scavenging code will shrink it down when its contents are not in use.
-static const int kMaxFreeListLength = 256;
-
-// Lower and upper bounds on the per-thread cache sizes
-static const size_t kMinThreadCacheSize = kMaxSize * 2;
-static const size_t kMaxThreadCacheSize = 2 << 20;
-
-// Default bound on the total amount of thread caches
-static const size_t kDefaultOverallThreadCacheSize = 16 << 20;
-
-// For all span-lengths < kMaxPages we keep an exact-size list.
-// REQUIRED: kMaxPages >= kMinSystemAlloc;
-static const size_t kMaxPages = kMinSystemAlloc;
-
-/* The smallest prime > 2^n */
-static int primes_list[] = {
-    // Small values might cause high rates of sampling
-    // and hence commented out.
-    // 2, 5, 11, 17, 37, 67, 131, 257,
-    // 521, 1031, 2053, 4099, 8209, 16411,
-    32771, 65537, 131101, 262147, 524309, 1048583,
-    2097169, 4194319, 8388617, 16777259, 33554467 };
-
-// Twice the approximate gap between sampling actions.
-// I.e., we take one sample approximately once every
-//      tcmalloc_sample_parameter/2
-// bytes of allocation, i.e., ~ once every 128KB.
-// Must be a prime number.
-#ifdef NO_TCMALLOC_SAMPLES
-DEFINE_int64(tcmalloc_sample_parameter, 0,
-             "Unused: code is compiled with NO_TCMALLOC_SAMPLES");
-static size_t sample_period = 0;
-#else
-DEFINE_int64(tcmalloc_sample_parameter, 262147,
-         "Twice the approximate gap between sampling actions."
-         " Must be a prime number. Otherwise will be rounded up to a "
-         " larger prime number");
-static size_t sample_period = 262147;
-#endif
-
-// Protects sample_period above
-static SpinLock sample_period_lock = SPINLOCK_INITIALIZER;
-
-// Parameters for controlling how fast memory is returned to the OS.
-
-DEFINE_double(tcmalloc_release_rate, 1,
-              "Rate at which we release unused memory to the system.  "
-              "Zero means we never release memory back to the system.  "
-              "Increase this flag to return memory faster; decrease it "
-              "to return memory slower.  Reasonable rates are in the "
-              "range [0,10]");
-
-//-------------------------------------------------------------------
-// Mapping from size to size_class and vice versa
-//-------------------------------------------------------------------
-
-// Sizes <= 1024 have an alignment >= 8.  So for such sizes we have an
-// array indexed by ceil(size/8).  Sizes > 1024 have an alignment >= 128.
-// So for these larger sizes we have an array indexed by ceil(size/128).
-//
-// We flatten both logical arrays into one physical array and use
-// arithmetic to compute an appropriate index.  The constants used by
-// ClassIndex() were selected to make the flattening work.
-//
-// Examples:
-//   Size       Expression                      Index
-//   -------------------------------------------------------
-//   0          (0 + 7) / 8                     0
-//   1          (1 + 7) / 8                     1
-//   ...
-//   1024       (1024 + 7) / 8                  128
-//   1025       (1025 + 127 + (120<<7)) / 128   129
-//   ...
-//   32768      (32768 + 127 + (120<<7)) / 128  376
-static const size_t kMaxSmallSize = 1024;
-static const int shift_amount[2] = { 3, 7 };  // For divides by 8 or 128
-static const int add_amount[2] = { 7, 127 + (120 << 7) };
-static unsigned char class_array[377];
-
-// Compute index of the class_array[] entry for a given size
-static inline int ClassIndex(size_t s) {
-  const int i = (s > kMaxSmallSize);
-  return static_cast<int>((s + add_amount[i]) >> shift_amount[i]);
-}
-
-// Mapping from size class to max size storable in that class
-static size_t class_to_size[kNumClasses];
-
-// Mapping from size class to number of pages to allocate at a time
-static size_t class_to_pages[kNumClasses];
-
-// Hardened singly linked list.  We make this a class to allow compiler to
-// statically prevent mismatching hardened and non-hardened list
-class HardenedSLL {
-public:
-    static ALWAYS_INLINE HardenedSLL create(void* value)
-    {
-        HardenedSLL result;
-        result.m_value = value;
-        return result;
-    }
-
-    static ALWAYS_INLINE HardenedSLL null()
-    {
-        HardenedSLL result;
-        result.m_value = 0;
-        return result;
-    }
-
-    ALWAYS_INLINE void setValue(void* value) { m_value = value; }
-    ALWAYS_INLINE void* value() const { return m_value; }
-    ALWAYS_INLINE bool operator!() const { return !m_value; }
-    typedef void* (HardenedSLL::*UnspecifiedBoolType);
-    ALWAYS_INLINE operator UnspecifiedBoolType() const { return m_value ? &HardenedSLL::m_value : 0; }
-
-    bool operator!=(const HardenedSLL& other) const { return m_value != other.m_value; }
-    bool operator==(const HardenedSLL& other) const { return m_value == other.m_value; }
-
-private:
-    void* m_value;
-};
-
-// TransferCache is used to cache transfers of num_objects_to_move[size_class]
-// back and forth between thread caches and the central cache for a given size
-// class.
-struct TCEntry {
-  HardenedSLL head;  // Head of chain of objects.
-  HardenedSLL tail;  // Tail of chain of objects.
-};
-// A central cache freelist can have anywhere from 0 to kNumTransferEntries
-// slots to put link list chains into.  To keep memory usage bounded the total
-// number of TCEntries across size classes is fixed.  Currently each size
-// class is initially given one TCEntry which also means that the maximum any
-// one class can have is kNumClasses.
-static const int kNumTransferEntries = kNumClasses;
-
-// Note: the following only works for "n"s that fit in 32-bits, but
-// that is fine since we only use it for small sizes.
-static inline int LgFloor(size_t n) {
-  int log = 0;
-  for (int i = 4; i >= 0; --i) {
-    int shift = (1 << i);
-    size_t x = n >> shift;
-    if (x != 0) {
-      n = x;
-      log += shift;
-    }
-  }
-  ASSERT(n == 1);
-  return log;
-}
-
-// Functions for using our simple hardened singly linked list
-static ALWAYS_INLINE HardenedSLL SLL_Next(HardenedSLL t, uintptr_t entropy) {
-    return HardenedSLL::create(XOR_MASK_PTR_WITH_KEY(*(reinterpret_cast<void**>(t.value())), t.value(), entropy));
-}
-
-static ALWAYS_INLINE void SLL_SetNext(HardenedSLL t, HardenedSLL n, uintptr_t entropy) {
-    *(reinterpret_cast<void**>(t.value())) = XOR_MASK_PTR_WITH_KEY(n.value(), t.value(), entropy);
-}
-
-static ALWAYS_INLINE void SLL_Push(HardenedSLL* list, HardenedSLL element, uintptr_t entropy) {
-  SLL_SetNext(element, *list, entropy);
-  *list = element;
-}
-
-static ALWAYS_INLINE HardenedSLL SLL_Pop(HardenedSLL *list, uintptr_t entropy) {
-  HardenedSLL result = *list;
-  *list = SLL_Next(*list, entropy);
-  return result;
-}
-
-// Remove N elements from a linked list to which head points.  head will be
-// modified to point to the new head.  start and end will point to the first
-// and last nodes of the range.  Note that end will point to NULL after this
-// function is called.
-
-static ALWAYS_INLINE void SLL_PopRange(HardenedSLL* head, int N, HardenedSLL *start, HardenedSLL *end, uintptr_t entropy) {
-  if (N == 0) {
-    *start = HardenedSLL::null();
-    *end = HardenedSLL::null();
-    return;
-  }
-
-  HardenedSLL tmp = *head;
-  for (int i = 1; i < N; ++i) {
-    tmp = SLL_Next(tmp, entropy);
-  }
-
-  *start = *head;
-  *end = tmp;
-  *head = SLL_Next(tmp, entropy);
-  // Unlink range from list.
-  SLL_SetNext(tmp, HardenedSLL::null(), entropy);
-}
-
-static ALWAYS_INLINE void SLL_PushRange(HardenedSLL *head, HardenedSLL start, HardenedSLL end, uintptr_t entropy) {
-  if (!start) return;
-  SLL_SetNext(end, *head, entropy);
-  *head = start;
-}
-
-static ALWAYS_INLINE size_t SLL_Size(HardenedSLL head, uintptr_t entropy) {
-  int count = 0;
-  while (head) {
-    count++;
-    head = SLL_Next(head, entropy);
-  }
-  return count;
-}
-
-// Setup helper functions.
-
-static ALWAYS_INLINE size_t SizeClass(size_t size) {
-  return class_array[ClassIndex(size)];
-}
-
-// Get the byte-size for a specified class
-static ALWAYS_INLINE size_t ByteSizeForClass(size_t cl) {
-  return class_to_size[cl];
-}
-static int NumMoveSize(size_t size) {
-  if (size == 0) return 0;
-  // Use approx 64k transfers between thread and central caches.
-  int num = static_cast<int>(64.0 * 1024.0 / size);
-  if (num < 2) num = 2;
-  // Clamp well below kMaxFreeListLength to avoid ping pong between central
-  // and thread caches.
-  if (num > static_cast<int>(0.8 * kMaxFreeListLength))
-    num = static_cast<int>(0.8 * kMaxFreeListLength);
-
-  // Also, avoid bringing in too many objects into small object free
-  // lists.  There are lots of such lists, and if we allow each one to
-  // fetch too many at a time, we end up having to scavenge too often
-  // (especially when there are lots of threads and each thread gets a
-  // small allowance for its thread cache).
-  //
-  // TODO: Make thread cache free list sizes dynamic so that we do not
-  // have to equally divide a fixed resource amongst lots of threads.
-  if (num > 32) num = 32;
-
-  return num;
-}
-
-// Initialize the mapping arrays
-static void InitSizeClasses() {
-  // Do some sanity checking on add_amount[]/shift_amount[]/class_array[]
-  if (ClassIndex(0) < 0) {
-    MESSAGE("Invalid class index %d for size 0\n", ClassIndex(0));
-    CRASH();
-  }
-  if (static_cast<size_t>(ClassIndex(kMaxSize)) >= sizeof(class_array)) {
-    MESSAGE("Invalid class index %d for kMaxSize\n", ClassIndex(kMaxSize));
-    CRASH();
-  }
-
-  // Compute the size classes we want to use
-  size_t sc = 1;   // Next size class to assign
-  unsigned char alignshift = kAlignShift;
-  int last_lg = -1;
-  for (size_t size = kAlignment; size <= kMaxSize; size += (1 << alignshift)) {
-    int lg = LgFloor(size);
-    if (lg > last_lg) {
-      // Increase alignment every so often.
-      //
-      // Since we double the alignment every time size doubles and
-      // size >= 128, this means that space wasted due to alignment is
-      // at most 16/128 i.e., 12.5%.  Plus we cap the alignment at 256
-      // bytes, so the space wasted as a percentage starts falling for
-      // sizes > 2K.
-      if ((lg >= 7) && (alignshift < 8)) {
-        alignshift++;
-      }
-      last_lg = lg;
-    }
-
-    // Allocate enough pages so leftover is less than 1/8 of total.
-    // This bounds wasted space to at most 12.5%.
-    size_t psize = kPageSize;
-    while ((psize % size) > (psize >> 3)) {
-      psize += kPageSize;
-    }
-    const size_t my_pages = psize >> kPageShift;
-
-    if (sc > 1 && my_pages == class_to_pages[sc-1]) {
-      // See if we can merge this into the previous class without
-      // increasing the fragmentation of the previous class.
-      const size_t my_objects = (my_pages << kPageShift) / size;
-      const size_t prev_objects = (class_to_pages[sc-1] << kPageShift)
-                                  / class_to_size[sc-1];
-      if (my_objects == prev_objects) {
-        // Adjust last class to include this size
-        class_to_size[sc-1] = size;
-        continue;
-      }
-    }
-
-    // Add new class
-    class_to_pages[sc] = my_pages;
-    class_to_size[sc] = size;
-    sc++;
-  }
-  if (sc != kNumClasses) {
-    MESSAGE("wrong number of size classes: found %" PRIuS " instead of %d\n",
-            sc, int(kNumClasses));
-    CRASH();
-  }
-
-  // Initialize the mapping arrays
-  int next_size = 0;
-  for (unsigned char c = 1; c < kNumClasses; c++) {
-    const size_t max_size_in_class = class_to_size[c];
-    for (size_t s = next_size; s <= max_size_in_class; s += kAlignment) {
-      class_array[ClassIndex(s)] = c;
-    }
-    next_size = static_cast<int>(max_size_in_class + kAlignment);
-  }
-
-  // Double-check sizes just to be safe
-  for (size_t size = 0; size <= kMaxSize; size++) {
-    const size_t sc = SizeClass(size);
-    if (sc == 0) {
-      MESSAGE("Bad size class %" PRIuS " for %" PRIuS "\n", sc, size);
-      CRASH();
-    }
-    if (sc > 1 && size <= class_to_size[sc-1]) {
-      MESSAGE("Allocating unnecessarily large class %" PRIuS " for %" PRIuS
-              "\n", sc, size);
-      CRASH();
-    }
-    if (sc >= kNumClasses) {
-      MESSAGE("Bad size class %" PRIuS " for %" PRIuS "\n", sc, size);
-      CRASH();
-    }
-    const size_t s = class_to_size[sc];
-    if (size > s) {
-     MESSAGE("Bad size %" PRIuS " for %" PRIuS " (sc = %" PRIuS ")\n", s, size, sc);
-      CRASH();
-    }
-    if (s == 0) {
-      MESSAGE("Bad size %" PRIuS " for %" PRIuS " (sc = %" PRIuS ")\n", s, size, sc);
-      CRASH();
-    }
-  }
-
-  // Initialize the num_objects_to_move array.
-  for (size_t cl = 1; cl  < kNumClasses; ++cl) {
-    num_objects_to_move[cl] = NumMoveSize(ByteSizeForClass(cl));
-  }
-
-#ifndef WTF_CHANGES
-  if (false) {
-    // Dump class sizes and maximum external wastage per size class
-    for (size_t cl = 1; cl  < kNumClasses; ++cl) {
-      const int alloc_size = class_to_pages[cl] << kPageShift;
-      const int alloc_objs = alloc_size / class_to_size[cl];
-      const int min_used = (class_to_size[cl-1] + 1) * alloc_objs;
-      const int max_waste = alloc_size - min_used;
-      MESSAGE("SC %3d [ %8d .. %8d ] from %8d ; %2.0f%% maxwaste\n",
-              int(cl),
-              int(class_to_size[cl-1] + 1),
-              int(class_to_size[cl]),
-              int(class_to_pages[cl] << kPageShift),
-              max_waste * 100.0 / alloc_size
-              );
-    }
-  }
-#endif
-}
-
-// -------------------------------------------------------------------------
-// Simple allocator for objects of a specified type.  External locking
-// is required before accessing one of these objects.
-// -------------------------------------------------------------------------
-
-// Metadata allocator -- keeps stats about how many bytes allocated
-static uint64_t metadata_system_bytes = 0;
-static void* MetaDataAlloc(size_t bytes) {
-  void* result = TCMalloc_SystemAlloc(bytes, 0);
-  if (result != NULL) {
-    metadata_system_bytes += bytes;
-  }
-  return result;
-}
-
-template <class T>
-class PageHeapAllocator {
- private:
-  // How much to allocate from system at a time
-  static const size_t kAllocIncrement = 32 << 10;
-
-  // Aligned size of T
-  static const size_t kAlignedSize
-  = (((sizeof(T) + kAlignment - 1) / kAlignment) * kAlignment);
-
-  // Free area from which to carve new objects
-  char* free_area_;
-  size_t free_avail_;
-
-  // Linked list of all regions allocated by this allocator
-  HardenedSLL allocated_regions_;
-
-  // Free list of already carved objects
-  HardenedSLL free_list_;
-
-  // Number of allocated but unfreed objects
-  int inuse_;
-  uintptr_t entropy_;
-
- public:
-  void Init(uintptr_t entropy) {
-    ASSERT(kAlignedSize <= kAllocIncrement);
-    inuse_ = 0;
-    allocated_regions_ = HardenedSLL::null();
-    free_area_ = NULL;
-    free_avail_ = 0;
-    free_list_.setValue(NULL);
-    entropy_ = entropy;
-  }
-
-  T* New() {
-    // Consult free list
-    void* result;
-    if (free_list_) {
-      result = free_list_.value();
-      free_list_ = SLL_Next(free_list_, entropy_);
-    } else {
-      if (free_avail_ < kAlignedSize) {
-        // Need more room
-        char* new_allocation = reinterpret_cast<char*>(MetaDataAlloc(kAllocIncrement));
-        if (!new_allocation)
-          CRASH();
-
-        HardenedSLL new_head = HardenedSLL::create(new_allocation);
-        SLL_SetNext(new_head, allocated_regions_, entropy_);
-        allocated_regions_ = new_head;
-        free_area_ = new_allocation + kAlignedSize;
-        free_avail_ = kAllocIncrement - kAlignedSize;
-      }
-      result = free_area_;
-      free_area_ += kAlignedSize;
-      free_avail_ -= kAlignedSize;
-    }
-    inuse_++;
-    return reinterpret_cast<T*>(result);
-  }
-
-  void Delete(T* p) {
-    HardenedSLL new_head = HardenedSLL::create(p);
-    SLL_SetNext(new_head, free_list_, entropy_);
-    free_list_ = new_head;
-    inuse_--;
-  }
-
-  int inuse() const { return inuse_; }
-
-#if defined(WTF_CHANGES) && OS(DARWIN)
-  template <class Recorder>
-  void recordAdministrativeRegions(Recorder& recorder, const RemoteMemoryReader& reader)
-  {
-      for (HardenedSLL adminAllocation = allocated_regions_; adminAllocation; adminAllocation.setValue(reader.nextEntryInHardenedLinkedList(reinterpret_cast<void**>(adminAllocation.value()), entropy_)))
-          recorder.recordRegion(reinterpret_cast<vm_address_t>(adminAllocation.value()), kAllocIncrement);
-  }
-#endif
-};
-
-// -------------------------------------------------------------------------
-// Span - a contiguous run of pages
-// -------------------------------------------------------------------------
-
-// Type that can hold a page number
-typedef uintptr_t PageID;
-
-// Type that can hold the length of a run of pages
-typedef uintptr_t Length;
-
-static const Length kMaxValidPages = (~static_cast<Length>(0)) >> kPageShift;
-
-// Convert byte size into pages.  This won't overflow, but may return
-// an unreasonably large value if bytes is huge enough.
-static inline Length pages(size_t bytes) {
-  return (bytes >> kPageShift) +
-      ((bytes & (kPageSize - 1)) > 0 ? 1 : 0);
-}
-
-// Convert a user size into the number of bytes that will actually be
-// allocated
-static size_t AllocationSize(size_t bytes) {
-  if (bytes > kMaxSize) {
-    // Large object: we allocate an integral number of pages
-    ASSERT(bytes <= (kMaxValidPages << kPageShift));
-    return pages(bytes) << kPageShift;
-  } else {
-    // Small object: find the size class to which it belongs
-    return ByteSizeForClass(SizeClass(bytes));
-  }
-}
-
-enum {
-    kSpanCookieBits = 10,
-    kSpanCookieMask = (1 << 10) - 1,
-    kSpanThisShift = 7
-};
-
-static uint32_t spanValidationCookie;
-static uint32_t spanInitializerCookie()
-{
-    static uint32_t value = EntropySource<sizeof(uint32_t)>::value() & kSpanCookieMask;
-    spanValidationCookie = value;
-    return value;
-}
-
-// Information kept for a span (a contiguous run of pages).
-struct Span {
-  PageID        start;          // Starting page number
-  Length        length;         // Number of pages in span
-  Span* next(uintptr_t entropy) const { return XOR_MASK_PTR_WITH_KEY(m_next, this, entropy); }
-  Span* remoteNext(const Span* remoteSpanPointer, uintptr_t entropy) const { return XOR_MASK_PTR_WITH_KEY(m_next, remoteSpanPointer, entropy); }
-  Span* prev(uintptr_t entropy) const { return XOR_MASK_PTR_WITH_KEY(m_prev, this, entropy); }
-  void setNext(Span* next, uintptr_t entropy) { m_next = XOR_MASK_PTR_WITH_KEY(next, this, entropy); }
-  void setPrev(Span* prev, uintptr_t entropy) { m_prev = XOR_MASK_PTR_WITH_KEY(prev, this, entropy); }
-
-private:
-  Span*         m_next;           // Used when in link list
-  Span*         m_prev;           // Used when in link list
-public:
-  HardenedSLL    objects;        // Linked list of free objects
-  unsigned int  free : 1;       // Is the span free
-#ifndef NO_TCMALLOC_SAMPLES
-  unsigned int  sample : 1;     // Sampled object?
-#endif
-  unsigned int  sizeclass : 8;  // Size-class for small objects (or 0)
-  unsigned int  refcount : 11;  // Number of non-free objects
-  bool decommitted : 1;
-  void initCookie()
-  {
-      m_cookie = ((reinterpret_cast<uintptr_t>(this) >> kSpanThisShift) & kSpanCookieMask) ^ spanInitializerCookie();
-  }
-  void clearCookie() { m_cookie = 0; }
-  bool isValid() const
-  {
-      return (((reinterpret_cast<uintptr_t>(this) >> kSpanThisShift) & kSpanCookieMask) ^ m_cookie) == spanValidationCookie;
-  }
-private:
-  uint32_t m_cookie : kSpanCookieBits;
-
-#undef SPAN_HISTORY
-#ifdef SPAN_HISTORY
-  // For debugging, we can keep a log events per span
-  int nexthistory;
-  char history[64];
-  int value[64];
-#endif
-};
-
-#define ASSERT_SPAN_COMMITTED(span) ASSERT(!span->decommitted)
-
-#ifdef SPAN_HISTORY
-void Event(Span* span, char op, int v = 0) {
-  span->history[span->nexthistory] = op;
-  span->value[span->nexthistory] = v;
-  span->nexthistory++;
-  if (span->nexthistory == sizeof(span->history)) span->nexthistory = 0;
-}
-#else
-#define Event(s,o,v) ((void) 0)
-#endif
-
-// Allocator/deallocator for spans
-static PageHeapAllocator<Span> span_allocator;
-static Span* NewSpan(PageID p, Length len) {
-  Span* result = span_allocator.New();
-  memset(result, 0, sizeof(*result));
-  result->start = p;
-  result->length = len;
-  result->initCookie();
-#ifdef SPAN_HISTORY
-  result->nexthistory = 0;
-#endif
-  return result;
-}
-
-static inline void DeleteSpan(Span* span) {
-  RELEASE_ASSERT(span->isValid());
-#ifndef NDEBUG
-  // In debug mode, trash the contents of deleted Spans
-  memset(span, 0x3f, sizeof(*span));
-#endif
-  span->clearCookie();
-  span_allocator.Delete(span);
-}
-
-// -------------------------------------------------------------------------
-// Doubly linked list of spans.
-// -------------------------------------------------------------------------
-
-static inline void DLL_Init(Span* list, uintptr_t entropy) {
-  list->setNext(list, entropy);
-  list->setPrev(list, entropy);
-}
-
-static inline void DLL_Remove(Span* span, uintptr_t entropy) {
-  span->prev(entropy)->setNext(span->next(entropy), entropy);
-  span->next(entropy)->setPrev(span->prev(entropy), entropy);
-  span->setPrev(NULL, entropy);
-  span->setNext(NULL, entropy);
-}
-
-static ALWAYS_INLINE bool DLL_IsEmpty(const Span* list, uintptr_t entropy) {
-  return list->next(entropy) == list;
-}
-
-static int DLL_Length(const Span* list, uintptr_t entropy) {
-  int result = 0;
-  for (Span* s = list->next(entropy); s != list; s = s->next(entropy)) {
-    result++;
-  }
-  return result;
-}
-
-#if 0 /* Not needed at the moment -- causes compiler warnings if not used */
-static void DLL_Print(const char* label, const Span* list) {
-  MESSAGE("%-10s %p:", label, list);
-  for (const Span* s = list->next; s != list; s = s->next) {
-    MESSAGE(" <%p,%u,%u>", s, s->start, s->length);
-  }
-  MESSAGE("\n");
-}
-#endif
-
-static inline void DLL_Prepend(Span* list, Span* span, uintptr_t entropy) {
-  span->setNext(list->next(entropy), entropy);
-  span->setPrev(list, entropy);
-  list->next(entropy)->setPrev(span, entropy);
-  list->setNext(span, entropy);
-}
-
-//-------------------------------------------------------------------
-// Data kept per size-class in central cache
-//-------------------------------------------------------------------
-
-class TCMalloc_Central_FreeList {
- public:
-  void Init(size_t cl, uintptr_t entropy);
-
-  // These methods all do internal locking.
-
-  // Insert the specified range into the central freelist.  N is the number of
-  // elements in the range.
-  void InsertRange(HardenedSLL start, HardenedSLL end, int N);
-
-  // Returns the actual number of fetched elements into N.
-  void RemoveRange(HardenedSLL* start, HardenedSLL* end, int *N);
-
-  // Returns the number of free objects in cache.
-  size_t length() {
-    SpinLockHolder h(&lock_);
-    return counter_;
-  }
-
-  // Returns the number of free objects in the transfer cache.
-  int tc_length() {
-    SpinLockHolder h(&lock_);
-    return used_slots_ * num_objects_to_move[size_class_];
-  }
-
-#ifdef WTF_CHANGES
-  template <class Finder, class Reader>
-  void enumerateFreeObjects(Finder& finder, const Reader& reader, TCMalloc_Central_FreeList* remoteCentralFreeList)
-  {
-    {
-      static const ptrdiff_t emptyOffset = reinterpret_cast<const char*>(&empty_) - reinterpret_cast<const char*>(this);
-      Span* remoteEmpty = reinterpret_cast<Span*>(reinterpret_cast<char*>(remoteCentralFreeList) + emptyOffset);
-      Span* remoteSpan = nonempty_.remoteNext(remoteEmpty, entropy_);
-      for (Span* span = reader(remoteEmpty); span && span != &empty_; remoteSpan = span->remoteNext(remoteSpan, entropy_), span = (remoteSpan ? reader(remoteSpan) : 0))
-        ASSERT(!span->objects);
-    }
-
-    ASSERT(!nonempty_.objects);
-    static const ptrdiff_t nonemptyOffset = reinterpret_cast<const char*>(&nonempty_) - reinterpret_cast<const char*>(this);
-
-    Span* remoteNonempty = reinterpret_cast<Span*>(reinterpret_cast<char*>(remoteCentralFreeList) + nonemptyOffset);
-    Span* remoteSpan = nonempty_.remoteNext(remoteNonempty, entropy_);
-
-    for (Span* span = reader(remoteSpan); span && remoteSpan != remoteNonempty; remoteSpan = span->remoteNext(remoteSpan, entropy_), span = (remoteSpan ? reader(remoteSpan) : 0)) {
-      for (HardenedSLL nextObject = span->objects; nextObject; nextObject.setValue(reader.nextEntryInHardenedLinkedList(reinterpret_cast<void**>(nextObject.value()), entropy_))) {
-        finder.visit(nextObject.value());
-      }
-    }
-  }
-#endif
-
-  uintptr_t entropy() const { return entropy_; }
- private:
-  // REQUIRES: lock_ is held
-  // Remove object from cache and return.
-  // Return NULL if no free entries in cache.
-  HardenedSLL FetchFromSpans();
-
-  // REQUIRES: lock_ is held
-  // Remove object from cache and return.  Fetches
-  // from pageheap if cache is empty.  Only returns
-  // NULL on allocation failure.
-  HardenedSLL FetchFromSpansSafe();
-
-  // REQUIRES: lock_ is held
-  // Release a linked list of objects to spans.
-  // May temporarily release lock_.
-  void ReleaseListToSpans(HardenedSLL start);
-
-  // REQUIRES: lock_ is held
-  // Release an object to spans.
-  // May temporarily release lock_.
-  ALWAYS_INLINE void ReleaseToSpans(HardenedSLL object);
-
-  // REQUIRES: lock_ is held
-  // Populate cache by fetching from the page heap.
-  // May temporarily release lock_.
-  ALWAYS_INLINE void Populate();
-
-  // REQUIRES: lock is held.
-  // Tries to make room for a TCEntry.  If the cache is full it will try to
-  // expand it at the cost of some other cache size.  Return false if there is
-  // no space.
-  bool MakeCacheSpace();
-
-  // REQUIRES: lock_ for locked_size_class is held.
-  // Picks a "random" size class to steal TCEntry slot from.  In reality it
-  // just iterates over the sizeclasses but does so without taking a lock.
-  // Returns true on success.
-  // May temporarily lock a "random" size class.
-  static ALWAYS_INLINE bool EvictRandomSizeClass(size_t locked_size_class, bool force);
-
-  // REQUIRES: lock_ is *not* held.
-  // Tries to shrink the Cache.  If force is true it will relase objects to
-  // spans if it allows it to shrink the cache.  Return false if it failed to
-  // shrink the cache.  Decrements cache_size_ on succeess.
-  // May temporarily take lock_.  If it takes lock_, the locked_size_class
-  // lock is released to the thread from holding two size class locks
-  // concurrently which could lead to a deadlock.
-  bool ShrinkCache(int locked_size_class, bool force);
-
-  // This lock protects all the data members.  cached_entries and cache_size_
-  // may be looked at without holding the lock.
-  SpinLock lock_;
-
-  // We keep linked lists of empty and non-empty spans.
-  size_t   size_class_;     // My size class
-  Span     empty_;          // Dummy header for list of empty spans
-  Span     nonempty_;       // Dummy header for list of non-empty spans
-  size_t   counter_;        // Number of free objects in cache entry
-
-  // Here we reserve space for TCEntry cache slots.  Since one size class can
-  // end up getting all the TCEntries quota in the system we just preallocate
-  // sufficient number of entries here.
-  TCEntry tc_slots_[kNumTransferEntries];
-
-  // Number of currently used cached entries in tc_slots_.  This variable is
-  // updated under a lock but can be read without one.
-  int32_t used_slots_;
-  // The current number of slots for this size class.  This is an
-  // adaptive value that is increased if there is lots of traffic
-  // on a given size class.
-  int32_t cache_size_;
-  uintptr_t entropy_;
-};
-
-#if COMPILER(CLANG) && defined(__has_warning)
-#pragma clang diagnostic push
-#if __has_warning("-Wunused-private-field")
-#pragma clang diagnostic ignored "-Wunused-private-field"
-#endif
-#endif
-
-// Pad each CentralCache object to multiple of 64 bytes
-template <size_t SizeToPad>
-class TCMalloc_Central_FreeListPadded_Template : public TCMalloc_Central_FreeList {
-private:
-    char pad[64 - SizeToPad];
-};
-
-// Zero-size specialization to avoid compiler error when TCMalloc_Central_FreeList happens
-// to be exactly 64 bytes.
-template <> class TCMalloc_Central_FreeListPadded_Template<0> : public TCMalloc_Central_FreeList {
-};
-
-typedef TCMalloc_Central_FreeListPadded_Template<sizeof(TCMalloc_Central_FreeList) % 64> TCMalloc_Central_FreeListPadded;
-
-#if COMPILER(CLANG) && defined(__has_warning)
-#pragma clang diagnostic pop
-#endif
-
-#if OS(DARWIN)
-struct Span;
-class TCMalloc_PageHeap;
-class TCMalloc_ThreadCache;
-template <typename T> class PageHeapAllocator;
-
-class FastMallocZone {
-public:
-    static void init();
-
-    static kern_return_t enumerate(task_t, void*, unsigned typeMmask, vm_address_t zoneAddress, memory_reader_t, vm_range_recorder_t);
-    static size_t goodSize(malloc_zone_t*, size_t size) { return size; }
-    static boolean_t check(malloc_zone_t*) { return true; }
-    static void  print(malloc_zone_t*, boolean_t) { }
-    static void log(malloc_zone_t*, void*) { }
-    static void forceLock(malloc_zone_t*) { }
-    static void forceUnlock(malloc_zone_t*) { }
-    static void statistics(malloc_zone_t*, malloc_statistics_t* stats) { memset(stats, 0, sizeof(malloc_statistics_t)); }
-
-private:
-    FastMallocZone(TCMalloc_PageHeap*, TCMalloc_ThreadCache**, TCMalloc_Central_FreeListPadded*, PageHeapAllocator<Span>*, PageHeapAllocator<TCMalloc_ThreadCache>*);
-    static size_t size(malloc_zone_t*, const void*);
-    static void* zoneMalloc(malloc_zone_t*, size_t);
-    static void* zoneCalloc(malloc_zone_t*, size_t numItems, size_t size);
-    static void zoneFree(malloc_zone_t*, void*);
-    static void* zoneRealloc(malloc_zone_t*, void*, size_t);
-    static void* zoneValloc(malloc_zone_t*, size_t) { LOG_ERROR("valloc is not supported"); return 0; }
-    static void zoneDestroy(malloc_zone_t*) { }
-
-    malloc_zone_t m_zone;
-    TCMalloc_PageHeap* m_pageHeap;
-    TCMalloc_ThreadCache** m_threadHeaps;
-    TCMalloc_Central_FreeListPadded* m_centralCaches;
-    PageHeapAllocator<Span>* m_spanAllocator;
-    PageHeapAllocator<TCMalloc_ThreadCache>* m_pageHeapAllocator;
-};
-
-#endif
-
-#endif
-
-#ifndef WTF_CHANGES
-// This #ifdef should almost never be set.  Set NO_TCMALLOC_SAMPLES if
-// you're porting to a system where you really can't get a stacktrace.
-#ifdef NO_TCMALLOC_SAMPLES
-// We use #define so code compiles even if you #include stacktrace.h somehow.
-# define GetStackTrace(stack, depth, skip)  (0)
-#else
-# include <google/stacktrace.h>
-#endif
-#endif
-
-// Even if we have support for thread-local storage in the compiler
-// and linker, the OS may not support it.  We need to check that at
-// runtime.  Right now, we have to keep a manual set of "bad" OSes.
-#if defined(HAVE_TLS)
-  static bool kernel_supports_tls = false;      // be conservative
-  static inline bool KernelSupportsTLS() {
-    return kernel_supports_tls;
-  }
-# if !HAVE_DECL_UNAME   // if too old for uname, probably too old for TLS
-    static void CheckIfKernelSupportsTLS() {
-      kernel_supports_tls = false;
-    }
-# else
-#   include <sys/utsname.h>    // DECL_UNAME checked for <sys/utsname.h> too
-    static void CheckIfKernelSupportsTLS() {
-      struct utsname buf;
-      if (uname(&buf) != 0) {   // should be impossible
-        MESSAGE("uname failed assuming no TLS support (errno=%d)\n", errno);
-        kernel_supports_tls = false;
-      } else if (strcasecmp(buf.sysname, "linux") == 0) {
-        // The linux case: the first kernel to support TLS was 2.6.0
-        if (buf.release[0] < '2' && buf.release[1] == '.')    // 0.x or 1.x
-          kernel_supports_tls = false;
-        else if (buf.release[0] == '2' && buf.release[1] == '.' &&
-                 buf.release[2] >= '0' && buf.release[2] < '6' &&
-                 buf.release[3] == '.')                       // 2.0 - 2.5
-          kernel_supports_tls = false;
-        else
-          kernel_supports_tls = true;
-      } else {        // some other kernel, we'll be optimisitic
-        kernel_supports_tls = true;
-      }
-      // TODO(csilvers): VLOG(1) the tls status once we support RAW_VLOG
-    }
-#  endif  // HAVE_DECL_UNAME
-#endif    // HAVE_TLS
-
-// __THROW is defined in glibc systems.  It means, counter-intuitively,
-// "This function will never throw an exception."  It's an optional
-// optimization tool, but we may need to use it to match glibc prototypes.
-#ifndef __THROW    // I guess we're not on a glibc system
-# define __THROW   // __THROW is just an optimization, so ok to make it ""
-#endif
-
-// -------------------------------------------------------------------------
-// Stack traces kept for sampled allocations
-//   The following state is protected by pageheap_lock_.
-// -------------------------------------------------------------------------
-
-// size/depth are made the same size as a pointer so that some generic
-// code below can conveniently cast them back and forth to void*.
-static const int kMaxStackDepth = 31;
-struct StackTrace {
-  uintptr_t size;          // Size of object
-  uintptr_t depth;         // Number of PC values stored in array below
-  void*     stack[kMaxStackDepth];
-};
-static PageHeapAllocator<StackTrace> stacktrace_allocator;
-static Span sampled_objects;
-
-// -------------------------------------------------------------------------
-// Map from page-id to per-page data
-// -------------------------------------------------------------------------
-
-// We use PageMap2<> for 32-bit and PageMap3<> for 64-bit machines.
-// We also use a simple one-level cache for hot PageID-to-sizeclass mappings,
-// because sometimes the sizeclass is all the information we need.
-
-// Selector class -- general selector uses 3-level map
-template <int BITS> class MapSelector {
- public:
-  typedef TCMalloc_PageMap3<BITS-kPageShift> Type;
-  typedef PackedCache<BITS, uint64_t> CacheType;
-};
-
-#if defined(WTF_CHANGES)
-#if CPU(X86_64)
-// On all known X86-64 platforms, the upper 16 bits are always unused and therefore 
-// can be excluded from the PageMap key.
-// See http://en.wikipedia.org/wiki/X86-64#Virtual_address_space_details
-
-static const size_t kBitsUnusedOn64Bit = 16;
-#else
-static const size_t kBitsUnusedOn64Bit = 0;
-#endif
-
-// A three-level map for 64-bit machines
-template <> class MapSelector<64> {
- public:
-  typedef TCMalloc_PageMap3<64 - kPageShift - kBitsUnusedOn64Bit> Type;
-  typedef PackedCache<64, uint64_t> CacheType;
-};
-#endif
-
-// A two-level map for 32-bit machines
-template <> class MapSelector<32> {
- public:
-  typedef TCMalloc_PageMap2<32 - kPageShift> Type;
-  typedef PackedCache<32 - kPageShift, uint16_t> CacheType;
-};
-
-// -------------------------------------------------------------------------
-// Page-level allocator
-//  * Eager coalescing
-//
-// Heap for page-level allocation.  We allow allocating and freeing a
-// contiguous runs of pages (called a "span").
-// -------------------------------------------------------------------------
-
-#if USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
-// The page heap maintains a free list for spans that are no longer in use by
-// the central cache or any thread caches. We use a background thread to
-// periodically scan the free list and release a percentage of it back to the OS.
-
-// If free_committed_pages_ exceeds kMinimumFreeCommittedPageCount, the
-// background thread:
-//     - wakes up
-//     - pauses for kScavengeDelayInSeconds
-//     - returns to the OS a percentage of the memory that remained unused during
-//       that pause (kScavengePercentage * min_free_committed_pages_since_last_scavenge_)
-// The goal of this strategy is to reduce memory pressure in a timely fashion
-// while avoiding thrashing the OS allocator.
-
-// Time delay before the page heap scavenger will consider returning pages to
-// the OS.
-static const int kScavengeDelayInSeconds = 2;
-
-// Approximate percentage of free committed pages to return to the OS in one
-// scavenge.
-static const float kScavengePercentage = .5f;
-
-// number of span lists to keep spans in when memory is returned.
-static const int kMinSpanListsWithSpans = 32;
-
-// Number of free committed pages that we want to keep around.  The minimum number of pages used when there
-// is 1 span in each of the first kMinSpanListsWithSpans spanlists.  Currently 528 pages.
-static const size_t kMinimumFreeCommittedPageCount = kMinSpanListsWithSpans * ((1.0f+kMinSpanListsWithSpans) / 2.0f);
-
-#endif
-
-static SpinLock pageheap_lock = SPINLOCK_INITIALIZER;
-
-class TCMalloc_PageHeap {
- public:
-  void init();
-
-  // Allocate a run of "n" pages.  Returns zero if out of memory.
-  Span* New(Length n);
-
-  // Delete the span "[p, p+n-1]".
-  // REQUIRES: span was returned by earlier call to New() and
-  //           has not yet been deleted.
-  void Delete(Span* span);
-
-  // Mark an allocated span as being used for small objects of the
-  // specified size-class.
-  // REQUIRES: span was returned by an earlier call to New()
-  //           and has not yet been deleted.
-  void RegisterSizeClass(Span* span, size_t sc);
-
-  // Split an allocated span into two spans: one of length "n" pages
-  // followed by another span of length "span->length - n" pages.
-  // Modifies "*span" to point to the first span of length "n" pages.
-  // Returns a pointer to the second span.
-  //
-  // REQUIRES: "0 < n < span->length"
-  // REQUIRES: !span->free
-  // REQUIRES: span->sizeclass == 0
-  Span* Split(Span* span, Length n);
-
-  // Return the descriptor for the specified page.
-  inline Span* GetDescriptor(PageID p) const {
-    return reinterpret_cast<Span*>(pagemap_.get(p));
-  }
-
-#ifdef WTF_CHANGES
-  inline Span* GetDescriptorEnsureSafe(PageID p)
-  {
-      pagemap_.Ensure(p, 1);
-      return GetDescriptor(p);
-  }
-    
-  size_t ReturnedBytes() const;
-#endif
-
-  // Dump state to stderr
-#ifndef WTF_CHANGES
-  void Dump(TCMalloc_Printer* out);
-#endif
-
-  // Return number of bytes allocated from system
-  inline uint64_t SystemBytes() const { return system_bytes_; }
-
-  // Return number of free bytes in heap
-  uint64_t FreeBytes() const {
-    return (static_cast<uint64_t>(free_pages_) << kPageShift);
-  }
-
-  bool Check();
-  size_t CheckList(Span* list, Length min_pages, Length max_pages, bool decommitted);
-
-  // Release all pages on the free list for reuse by the OS:
-  void ReleaseFreePages();
-  void ReleaseFreeList(Span*, Span*);
-
-  // Return 0 if we have no information, or else the correct sizeclass for p.
-  // Reads and writes to pagemap_cache_ do not require locking.
-  // The entries are 64 bits on 64-bit hardware and 16 bits on
-  // 32-bit hardware, and we don't mind raciness as long as each read of
-  // an entry yields a valid entry, not a partially updated entry.
-  size_t GetSizeClassIfCached(PageID p) const {
-    return pagemap_cache_.GetOrDefault(p, 0);
-  }
-  void CacheSizeClass(PageID p, size_t cl) const { pagemap_cache_.Put(p, cl); }
-
- private:
-  // Pick the appropriate map and cache types based on pointer size
-  typedef MapSelector<8*sizeof(uintptr_t)>::Type PageMap;
-  typedef MapSelector<8*sizeof(uintptr_t)>::CacheType PageMapCache;
-  PageMap pagemap_;
-  mutable PageMapCache pagemap_cache_;
-
-  // We segregate spans of a given size into two circular linked
-  // lists: one for normal spans, and one for spans whose memory
-  // has been returned to the system.
-  struct SpanList {
-    Span        normal;
-    Span        returned;
-  };
-
-  // List of free spans of length >= kMaxPages
-  SpanList large_;
-
-  // Array mapping from span length to a doubly linked list of free spans
-  SpanList free_[kMaxPages];
-
-  // Number of pages kept in free lists
-  uintptr_t free_pages_;
-
-  // Used for hardening
-  uintptr_t entropy_;
-
-  // Bytes allocated from system
-  uint64_t system_bytes_;
-
-#if USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
-  // Number of pages kept in free lists that are still committed.
-  Length free_committed_pages_;
-
-  // Minimum number of free committed pages since last scavenge. (Can be 0 if
-  // we've committed new pages since the last scavenge.)
-  Length min_free_committed_pages_since_last_scavenge_;
-#endif
-
-  bool GrowHeap(Length n);
-
-  // REQUIRES   span->length >= n
-  // Remove span from its free list, and move any leftover part of
-  // span into appropriate free lists.  Also update "span" to have
-  // length exactly "n" and mark it as non-free so it can be returned
-  // to the client.
-  //
-  // "released" is true iff "span" was found on a "returned" list.
-  void Carve(Span* span, Length n, bool released);
-
-  void RecordSpan(Span* span) {
-    pagemap_.set(span->start, span);
-    if (span->length > 1) {
-      pagemap_.set(span->start + span->length - 1, span);
-    }
-  }
-  
-    // Allocate a large span of length == n.  If successful, returns a
-  // span of exactly the specified length.  Else, returns NULL.
-  Span* AllocLarge(Length n);
-
-#if !USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
-  // Incrementally release some memory to the system.
-  // IncrementalScavenge(n) is called whenever n pages are freed.
-  void IncrementalScavenge(Length n);
-#endif
-
-  // Number of pages to deallocate before doing more scavenging
-  int64_t scavenge_counter_;
-
-  // Index of last free list we scavenged
-  size_t scavenge_index_;
-  
-#if defined(WTF_CHANGES) && OS(DARWIN)
-  friend class FastMallocZone;
-#endif
-
-#if USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
-  void initializeScavenger();
-  ALWAYS_INLINE void signalScavenger();
-  void scavenge();
-  ALWAYS_INLINE bool shouldScavenge() const;
-
-#if HAVE(DISPATCH_H) || OS(WINDOWS)
-  void periodicScavenge();
-  ALWAYS_INLINE bool isScavengerSuspended();
-  ALWAYS_INLINE void scheduleScavenger();
-  ALWAYS_INLINE void rescheduleScavenger();
-  ALWAYS_INLINE void suspendScavenger();
-#endif
-
-#if HAVE(DISPATCH_H)
-  dispatch_queue_t m_scavengeQueue;
-  dispatch_source_t m_scavengeTimer;
-  bool m_scavengingSuspended;
-#elif OS(WINDOWS)
-  static void CALLBACK scavengerTimerFired(void*, BOOLEAN);
-  HANDLE m_scavengeQueueTimer;
-#else 
-  static NO_RETURN_WITH_VALUE void* runScavengerThread(void*);
-  NO_RETURN void scavengerThread();
-
-  // Keeps track of whether the background thread is actively scavenging memory every kScavengeDelayInSeconds, or
-  // it's blocked waiting for more pages to be deleted.
-  bool m_scavengeThreadActive;
-
-  pthread_mutex_t m_scavengeMutex;
-  pthread_cond_t m_scavengeCondition;
-#endif
-
-#endif  // USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
-};
-
-void TCMalloc_PageHeap::init()
-{
-  pagemap_.init(MetaDataAlloc);
-  pagemap_cache_ = PageMapCache(0);
-  free_pages_ = 0;
-  system_bytes_ = 0;
-  entropy_ = HARDENING_ENTROPY;
-
-#if USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
-  free_committed_pages_ = 0;
-  min_free_committed_pages_since_last_scavenge_ = 0;
-#endif  // USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
-
-  scavenge_counter_ = 0;
-  // Start scavenging at kMaxPages list
-  scavenge_index_ = kMaxPages-1;
-  COMPILE_ASSERT(kNumClasses <= (1 << PageMapCache::kValuebits), valuebits);
-  DLL_Init(&large_.normal, entropy_);
-  DLL_Init(&large_.returned, entropy_);
-  for (size_t i = 0; i < kMaxPages; i++) {
-    DLL_Init(&free_[i].normal, entropy_);
-    DLL_Init(&free_[i].returned, entropy_);
-  }
-
-#if USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
-  initializeScavenger();
-#endif  // USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
-}
-
-#if USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
-
-#if HAVE(DISPATCH_H)
-
-void TCMalloc_PageHeap::initializeScavenger()
-{
-    m_scavengeQueue = dispatch_queue_create("com.apple.JavaScriptCore.FastMallocSavenger", NULL);
-    m_scavengeTimer = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, 0, 0, m_scavengeQueue);
-    uint64_t scavengeDelayInNanoseconds = kScavengeDelayInSeconds * NSEC_PER_SEC;
-    dispatch_time_t startTime = dispatch_time(DISPATCH_TIME_NOW, scavengeDelayInNanoseconds);
-    dispatch_source_set_timer(m_scavengeTimer, startTime, scavengeDelayInNanoseconds, scavengeDelayInNanoseconds / 10);
-    dispatch_source_set_event_handler(m_scavengeTimer, ^{ periodicScavenge(); });
-    m_scavengingSuspended = true;
-}
-
-ALWAYS_INLINE bool TCMalloc_PageHeap::isScavengerSuspended()
-{
-    ASSERT(pageheap_lock.IsHeld());
-    return m_scavengingSuspended;
-}
-
-ALWAYS_INLINE void TCMalloc_PageHeap::scheduleScavenger()
-{
-    ASSERT(pageheap_lock.IsHeld());
-    m_scavengingSuspended = false;
-    dispatch_resume(m_scavengeTimer);
-}
-
-ALWAYS_INLINE void TCMalloc_PageHeap::rescheduleScavenger()
-{
-    // Nothing to do here for libdispatch.
-}
-
-ALWAYS_INLINE void TCMalloc_PageHeap::suspendScavenger()
-{
-    ASSERT(pageheap_lock.IsHeld());
-    m_scavengingSuspended = true;
-    dispatch_suspend(m_scavengeTimer);
-}
-
-#elif OS(WINDOWS)
-
-void TCMalloc_PageHeap::scavengerTimerFired(void* context, BOOLEAN)
-{
-    static_cast<TCMalloc_PageHeap*>(context)->periodicScavenge();
-}
-
-void TCMalloc_PageHeap::initializeScavenger()
-{
-    m_scavengeQueueTimer = 0;
-}
-
-ALWAYS_INLINE bool TCMalloc_PageHeap::isScavengerSuspended()
-{
-    ASSERT(pageheap_lock.IsHeld());
-    return !m_scavengeQueueTimer;
-}
-
-ALWAYS_INLINE void TCMalloc_PageHeap::scheduleScavenger()
-{
-    // We need to use WT_EXECUTEONLYONCE here and reschedule the timer, because
-    // Windows will fire the timer event even when the function is already running.
-    ASSERT(pageheap_lock.IsHeld());
-    CreateTimerQueueTimer(&m_scavengeQueueTimer, 0, scavengerTimerFired, this, kScavengeDelayInSeconds * 1000, 0, WT_EXECUTEONLYONCE);
-}
-
-ALWAYS_INLINE void TCMalloc_PageHeap::rescheduleScavenger()
-{
-    // We must delete the timer and create it again, because it is not possible to retrigger a timer on Windows.
-    suspendScavenger();
-    scheduleScavenger();
-}
-
-ALWAYS_INLINE void TCMalloc_PageHeap::suspendScavenger()
-{
-    ASSERT(pageheap_lock.IsHeld());
-    HANDLE scavengeQueueTimer = m_scavengeQueueTimer;
-    m_scavengeQueueTimer = 0;
-    DeleteTimerQueueTimer(0, scavengeQueueTimer, 0);
-}
-
-#else
-
-void TCMalloc_PageHeap::initializeScavenger()
-{
-    // Create a non-recursive mutex.
-#if !defined(PTHREAD_MUTEX_NORMAL) || PTHREAD_MUTEX_NORMAL == PTHREAD_MUTEX_DEFAULT
-    pthread_mutex_init(&m_scavengeMutex, 0);
-#else
-    pthread_mutexattr_t attr;
-    pthread_mutexattr_init(&attr);
-    pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_NORMAL);
-
-    pthread_mutex_init(&m_scavengeMutex, &attr);
-
-    pthread_mutexattr_destroy(&attr);
-#endif
-
-    pthread_cond_init(&m_scavengeCondition, 0);
-    m_scavengeThreadActive = true;
-    pthread_t thread;
-    pthread_create(&thread, 0, runScavengerThread, this);
-}
-
-void* TCMalloc_PageHeap::runScavengerThread(void* context)
-{
-    static_cast<TCMalloc_PageHeap*>(context)->scavengerThread();
-#if (COMPILER(MSVC) || COMPILER(SUNCC))
-    // Without this, Visual Studio and Sun Studio will complain that this method does not return a value.
-    return 0;
-#endif
-}
-
-ALWAYS_INLINE void TCMalloc_PageHeap::signalScavenger()
-{
-    // shouldScavenge() should be called only when the pageheap_lock spinlock is held, additionally, 
-    // m_scavengeThreadActive is only set to false whilst pageheap_lock is held. The caller must ensure this is
-    // taken prior to calling this method. If the scavenger thread is sleeping and shouldScavenge() indicates there
-    // is memory to free the scavenger thread is signalled to start.
-    ASSERT(pageheap_lock.IsHeld());
-    if (!m_scavengeThreadActive && shouldScavenge())
-        pthread_cond_signal(&m_scavengeCondition);
-}
-
-#endif
-
-void TCMalloc_PageHeap::scavenge()
-{
-    size_t pagesToRelease = min_free_committed_pages_since_last_scavenge_ * kScavengePercentage;
-    size_t targetPageCount = std::max<size_t>(kMinimumFreeCommittedPageCount, free_committed_pages_ - pagesToRelease);
-
-    Length lastFreeCommittedPages = free_committed_pages_;
-    while (free_committed_pages_ > targetPageCount) {
-        ASSERT(Check());
-        for (int i = kMaxPages; i > 0 && free_committed_pages_ >= targetPageCount; i--) {
-            SpanList* slist = (static_cast<size_t>(i) == kMaxPages) ? &large_ : &free_[i];
-            // If the span size is bigger than kMinSpanListsWithSpans pages return all the spans in the list, else return all but 1 span.  
-            // Return only 50% of a spanlist at a time so spans of size 1 are not the only ones left.
-            size_t length = DLL_Length(&slist->normal, entropy_);
-            size_t numSpansToReturn = (i > kMinSpanListsWithSpans) ? length : length / 2;
-            for (int j = 0; static_cast<size_t>(j) < numSpansToReturn && !DLL_IsEmpty(&slist->normal, entropy_) && free_committed_pages_ > targetPageCount; j++) {
-                Span* s = slist->normal.prev(entropy_);
-                DLL_Remove(s, entropy_);
-                ASSERT(!s->decommitted);
-                if (!s->decommitted) {
-                    TCMalloc_SystemRelease(reinterpret_cast<void*>(s->start << kPageShift),
-                                           static_cast<size_t>(s->length << kPageShift));
-                    ASSERT(free_committed_pages_ >= s->length);
-                    free_committed_pages_ -= s->length;
-                    s->decommitted = true;
-                }
-                DLL_Prepend(&slist->returned, s, entropy_);
-            }
-        }
-
-        if (lastFreeCommittedPages == free_committed_pages_)
-            break;
-        lastFreeCommittedPages = free_committed_pages_;
-    }
-
-    min_free_committed_pages_since_last_scavenge_ = free_committed_pages_;
-}
-
-ALWAYS_INLINE bool TCMalloc_PageHeap::shouldScavenge() const 
-{
-    return free_committed_pages_ > kMinimumFreeCommittedPageCount; 
-}
-
-#endif  // USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
-
-inline Span* TCMalloc_PageHeap::New(Length n) {
-  ASSERT(Check());
-  ASSERT(n > 0);
-
-  // Find first size >= n that has a non-empty list
-  for (Length s = n; s < kMaxPages; s++) {
-    Span* ll = NULL;
-    bool released = false;
-    if (!DLL_IsEmpty(&free_[s].normal, entropy_)) {
-      // Found normal span
-      ll = &free_[s].normal;
-    } else if (!DLL_IsEmpty(&free_[s].returned, entropy_)) {
-      // Found returned span; reallocate it
-      ll = &free_[s].returned;
-      released = true;
-    } else {
-      // Keep looking in larger classes
-      continue;
-    }
-
-    Span* result = ll->next(entropy_);
-    Carve(result, n, released);
-#if USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
-    // The newly allocated memory is from a span that's in the normal span list (already committed).  Update the
-    // free committed pages count.
-    ASSERT(free_committed_pages_ >= n);
-    free_committed_pages_ -= n;
-    if (free_committed_pages_ < min_free_committed_pages_since_last_scavenge_) 
-      min_free_committed_pages_since_last_scavenge_ = free_committed_pages_;
-#endif  // USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
-    ASSERT(Check());
-    free_pages_ -= n;
-    return result;
-  }
-
-  Span* result = AllocLarge(n);
-  if (result != NULL) {
-      ASSERT_SPAN_COMMITTED(result);
-      return result;
-  }
-
-  // Grow the heap and try again
-  if (!GrowHeap(n)) {
-    ASSERT(Check());
-    return NULL;
-  }
-
-  return New(n);
-}
-
-Span* TCMalloc_PageHeap::AllocLarge(Length n) {
-  // find the best span (closest to n in size).
-  // The following loops implements address-ordered best-fit.
-  bool from_released = false;
-  Span *best = NULL;
-
-  // Search through normal list
-  for (Span* span = large_.normal.next(entropy_);
-       span != &large_.normal;
-       span = span->next(entropy_)) {
-    if (span->length >= n) {
-      if ((best == NULL)
-          || (span->length < best->length)
-          || ((span->length == best->length) && (span->start < best->start))) {
-        best = span;
-        from_released = false;
-      }
-    }
-  }
-
-  // Search through released list in case it has a better fit
-  for (Span* span = large_.returned.next(entropy_);
-       span != &large_.returned;
-       span = span->next(entropy_)) {
-    if (span->length >= n) {
-      if ((best == NULL)
-          || (span->length < best->length)
-          || ((span->length == best->length) && (span->start < best->start))) {
-        best = span;
-        from_released = true;
-      }
-    }
-  }
-
-  if (best != NULL) {
-    Carve(best, n, from_released);
-#if USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
-    // The newly allocated memory is from a span that's in the normal span list (already committed).  Update the
-    // free committed pages count.
-    ASSERT(free_committed_pages_ >= n);
-    free_committed_pages_ -= n;
-    if (free_committed_pages_ < min_free_committed_pages_since_last_scavenge_)
-      min_free_committed_pages_since_last_scavenge_ = free_committed_pages_;
-#endif  // USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
-    ASSERT(Check());
-    free_pages_ -= n;
-    return best;
-  }
-  return NULL;
-}
-
-Span* TCMalloc_PageHeap::Split(Span* span, Length n) {
-  ASSERT(0 < n);
-  ASSERT(n < span->length);
-  ASSERT(!span->free);
-  ASSERT(span->sizeclass == 0);
-  Event(span, 'T', n);
-
-  const Length extra = span->length - n;
-  Span* leftover = NewSpan(span->start + n, extra);
-  Event(leftover, 'U', extra);
-  RecordSpan(leftover);
-  pagemap_.set(span->start + n - 1, span); // Update map from pageid to span
-  span->length = n;
-
-  return leftover;
-}
-
-inline void TCMalloc_PageHeap::Carve(Span* span, Length n, bool released) {
-  ASSERT(n > 0);
-  DLL_Remove(span, entropy_);
-  span->free = 0;
-  Event(span, 'A', n);
-
-  if (released) {
-    // If the span chosen to carve from is decommited, commit the entire span at once to avoid committing spans 1 page at a time.
-    ASSERT(span->decommitted);
-    TCMalloc_SystemCommit(reinterpret_cast<void*>(span->start << kPageShift), static_cast<size_t>(span->length << kPageShift));
-    span->decommitted = false;
-#if USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
-    free_committed_pages_ += span->length;
-#endif
-  }
-  
-  const int extra = static_cast<int>(span->length - n);
-  ASSERT(extra >= 0);
-  if (extra > 0) {
-    Span* leftover = NewSpan(span->start + n, extra);
-    leftover->free = 1;
-    leftover->decommitted = false;
-    Event(leftover, 'S', extra);
-    RecordSpan(leftover);
-
-    // Place leftover span on appropriate free list
-    SpanList* listpair = (static_cast<size_t>(extra) < kMaxPages) ? &free_[extra] : &large_;
-    Span* dst = &listpair->normal;
-    DLL_Prepend(dst, leftover, entropy_);
-
-    span->length = n;
-    pagemap_.set(span->start + n - 1, span);
-  }
-}
-
-static ALWAYS_INLINE void mergeDecommittedStates(Span* destination, Span* other)
-{
-    if (destination->decommitted && !other->decommitted) {
-        TCMalloc_SystemRelease(reinterpret_cast<void*>(other->start << kPageShift),
-                               static_cast<size_t>(other->length << kPageShift));
-    } else if (other->decommitted && !destination->decommitted) {
-        TCMalloc_SystemRelease(reinterpret_cast<void*>(destination->start << kPageShift),
-                               static_cast<size_t>(destination->length << kPageShift));
-        destination->decommitted = true;
-    }
-}
-
-inline void TCMalloc_PageHeap::Delete(Span* span) {
-  ASSERT(Check());
-  ASSERT(!span->free);
-  ASSERT(span->length > 0);
-  ASSERT(GetDescriptor(span->start) == span);
-  ASSERT(GetDescriptor(span->start + span->length - 1) == span);
-  span->sizeclass = 0;
-#ifndef NO_TCMALLOC_SAMPLES
-  span->sample = 0;
-#endif
-
-  // Coalesce -- we guarantee that "p" != 0, so no bounds checking
-  // necessary.  We do not bother resetting the stale pagemap
-  // entries for the pieces we are merging together because we only
-  // care about the pagemap entries for the boundaries.
-#if USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
-  // Track the total size of the neighboring free spans that are committed.
-  Length neighboringCommittedSpansLength = 0;
-#endif
-  const PageID p = span->start;
-  const Length n = span->length;
-  Span* prev = GetDescriptor(p-1);
-  if (prev != NULL && prev->free) {
-    // Merge preceding span into this span
-    ASSERT(prev->start + prev->length == p);
-    const Length len = prev->length;
-#if USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
-    if (!prev->decommitted)
-        neighboringCommittedSpansLength += len;
-#endif
-    mergeDecommittedStates(span, prev);
-    DLL_Remove(prev, entropy_);
-    DeleteSpan(prev);
-    span->start -= len;
-    span->length += len;
-    pagemap_.set(span->start, span);
-    Event(span, 'L', len);
-  }
-  Span* next = GetDescriptor(p+n);
-  if (next != NULL && next->free) {
-    // Merge next span into this span
-    ASSERT(next->start == p+n);
-    const Length len = next->length;
-#if USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
-    if (!next->decommitted)
-        neighboringCommittedSpansLength += len;
-#endif
-    mergeDecommittedStates(span, next);
-    DLL_Remove(next, entropy_);
-    DeleteSpan(next);
-    span->length += len;
-    pagemap_.set(span->start + span->length - 1, span);
-    Event(span, 'R', len);
-  }
-
-  Event(span, 'D', span->length);
-  span->free = 1;
-  if (span->decommitted) {
-    if (span->length < kMaxPages)
-      DLL_Prepend(&free_[span->length].returned, span, entropy_);
-    else
-      DLL_Prepend(&large_.returned, span, entropy_);
-  } else {
-    if (span->length < kMaxPages)
-      DLL_Prepend(&free_[span->length].normal, span, entropy_);
-    else
-      DLL_Prepend(&large_.normal, span, entropy_);
-  }
-  free_pages_ += n;
-
-#if USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
-  if (span->decommitted) {
-      // If the merged span is decommitted, that means we decommitted any neighboring spans that were
-      // committed.  Update the free committed pages count.
-      free_committed_pages_ -= neighboringCommittedSpansLength;
-      if (free_committed_pages_ < min_free_committed_pages_since_last_scavenge_)
-            min_free_committed_pages_since_last_scavenge_ = free_committed_pages_;
-  } else {
-      // If the merged span remains committed, add the deleted span's size to the free committed pages count.
-      free_committed_pages_ += n;
-  }
-
-  // Make sure the scavenge thread becomes active if we have enough freed pages to release some back to the system.
-  signalScavenger();
-#else
-  IncrementalScavenge(n);
-#endif
-
-  ASSERT(Check());
-}
-
-#if !USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
-void TCMalloc_PageHeap::IncrementalScavenge(Length n) {
-  // Fast path; not yet time to release memory
-  scavenge_counter_ -= n;
-  if (scavenge_counter_ >= 0) return;  // Not yet time to scavenge
-
-  // If there is nothing to release, wait for so many pages before
-  // scavenging again.  With 4K pages, this comes to 16MB of memory.
-  static const size_t kDefaultReleaseDelay = 1 << 8;
-
-  // Find index of free list to scavenge
-  size_t index = scavenge_index_ + 1;
-  uintptr_t entropy = entropy_;
-  for (size_t i = 0; i < kMaxPages+1; i++) {
-    if (index > kMaxPages) index = 0;
-    SpanList* slist = (index == kMaxPages) ? &large_ : &free_[index];
-    if (!DLL_IsEmpty(&slist->normal, entropy)) {
-      // Release the last span on the normal portion of this list
-      Span* s = slist->normal.prev(entropy);
-      DLL_Remove(s, entropy_);
-      TCMalloc_SystemRelease(reinterpret_cast<void*>(s->start << kPageShift),
-                             static_cast<size_t>(s->length << kPageShift));
-      s->decommitted = true;
-      DLL_Prepend(&slist->returned, s, entropy);
-
-      scavenge_counter_ = std::max<size_t>(64UL, std::min<size_t>(kDefaultReleaseDelay, kDefaultReleaseDelay - (free_pages_ / kDefaultReleaseDelay)));
-
-      if (index == kMaxPages && !DLL_IsEmpty(&slist->normal, entropy))
-        scavenge_index_ = index - 1;
-      else
-        scavenge_index_ = index;
-      return;
-    }
-    index++;
-  }
-
-  // Nothing to scavenge, delay for a while
-  scavenge_counter_ = kDefaultReleaseDelay;
-}
-#endif
-
-void TCMalloc_PageHeap::RegisterSizeClass(Span* span, size_t sc) {
-  // Associate span object with all interior pages as well
-  ASSERT(!span->free);
-  ASSERT(GetDescriptor(span->start) == span);
-  ASSERT(GetDescriptor(span->start+span->length-1) == span);
-  Event(span, 'C', sc);
-  span->sizeclass = static_cast<unsigned int>(sc);
-  for (Length i = 1; i < span->length-1; i++) {
-    pagemap_.set(span->start+i, span);
-  }
-}
-    
-#ifdef WTF_CHANGES
-size_t TCMalloc_PageHeap::ReturnedBytes() const {
-    size_t result = 0;
-    for (unsigned s = 0; s < kMaxPages; s++) {
-        const int r_length = DLL_Length(&free_[s].returned, entropy_);
-        unsigned r_pages = s * r_length;
-        result += r_pages << kPageShift;
-    }
-    
-    for (Span* s = large_.returned.next(entropy_); s != &large_.returned; s = s->next(entropy_))
-        result += s->length << kPageShift;
-    return result;
-}
-#endif
-
-#ifndef WTF_CHANGES
-static double PagesToMB(uint64_t pages) {
-  return (pages << kPageShift) / 1048576.0;
-}
-
-void TCMalloc_PageHeap::Dump(TCMalloc_Printer* out) {
-  int nonempty_sizes = 0;
-  for (int s = 0; s < kMaxPages; s++) {
-    if (!DLL_IsEmpty(&free_[s].normal) || !DLL_IsEmpty(&free_[s].returned)) {
-      nonempty_sizes++;
-    }
-  }
-  out->printf("------------------------------------------------\n");
-  out->printf("PageHeap: %d sizes; %6.1f MB free\n",
-              nonempty_sizes, PagesToMB(free_pages_));
-  out->printf("------------------------------------------------\n");
-  uint64_t total_normal = 0;
-  uint64_t total_returned = 0;
-  for (int s = 0; s < kMaxPages; s++) {
-    const int n_length = DLL_Length(&free_[s].normal);
-    const int r_length = DLL_Length(&free_[s].returned);
-    if (n_length + r_length > 0) {
-      uint64_t n_pages = s * n_length;
-      uint64_t r_pages = s * r_length;
-      total_normal += n_pages;
-      total_returned += r_pages;
-      out->printf("%6u pages * %6u spans ~ %6.1f MB; %6.1f MB cum"
-                  "; unmapped: %6.1f MB; %6.1f MB cum\n",
-                  s,
-                  (n_length + r_length),
-                  PagesToMB(n_pages + r_pages),
-                  PagesToMB(total_normal + total_returned),
-                  PagesToMB(r_pages),
-                  PagesToMB(total_returned));
-    }
-  }
-
-  uint64_t n_pages = 0;
-  uint64_t r_pages = 0;
-  int n_spans = 0;
-  int r_spans = 0;
-  out->printf("Normal large spans:\n");
-  for (Span* s = large_.normal.next; s != &large_.normal; s = s->next) {
-    out->printf("   [ %6" PRIuS " pages ] %6.1f MB\n",
-                s->length, PagesToMB(s->length));
-    n_pages += s->length;
-    n_spans++;
-  }
-  out->printf("Unmapped large spans:\n");
-  for (Span* s = large_.returned.next; s != &large_.returned; s = s->next) {
-    out->printf("   [ %6" PRIuS " pages ] %6.1f MB\n",
-                s->length, PagesToMB(s->length));
-    r_pages += s->length;
-    r_spans++;
-  }
-  total_normal += n_pages;
-  total_returned += r_pages;
-  out->printf(">255   large * %6u spans ~ %6.1f MB; %6.1f MB cum"
-              "; unmapped: %6.1f MB; %6.1f MB cum\n",
-              (n_spans + r_spans),
-              PagesToMB(n_pages + r_pages),
-              PagesToMB(total_normal + total_returned),
-              PagesToMB(r_pages),
-              PagesToMB(total_returned));
-}
-#endif
-
-bool TCMalloc_PageHeap::GrowHeap(Length n) {
-  ASSERT(kMaxPages >= kMinSystemAlloc);
-  if (n > kMaxValidPages) return false;
-  Length ask = (n>kMinSystemAlloc) ? n : static_cast<Length>(kMinSystemAlloc);
-  size_t actual_size;
-  void* ptr = TCMalloc_SystemAlloc(ask << kPageShift, &actual_size, kPageSize);
-  if (ptr == NULL) {
-    if (n < ask) {
-      // Try growing just "n" pages
-      ask = n;
-      ptr = TCMalloc_SystemAlloc(ask << kPageShift, &actual_size, kPageSize);
-    }
-    if (ptr == NULL) return false;
-  }
-  ask = actual_size >> kPageShift;
-
-  uint64_t old_system_bytes = system_bytes_;
-  system_bytes_ += (ask << kPageShift);
-  const PageID p = reinterpret_cast<uintptr_t>(ptr) >> kPageShift;
-  ASSERT(p > 0);
-
-  // If we have already a lot of pages allocated, just pre allocate a bunch of
-  // memory for the page map. This prevents fragmentation by pagemap metadata
-  // when a program keeps allocating and freeing large blocks.
-
-  if (old_system_bytes < kPageMapBigAllocationThreshold
-      && system_bytes_ >= kPageMapBigAllocationThreshold) {
-    pagemap_.PreallocateMoreMemory();
-  }
-
-  // Make sure pagemap_ has entries for all of the new pages.
-  // Plus ensure one before and one after so coalescing code
-  // does not need bounds-checking.
-  if (pagemap_.Ensure(p-1, ask+2)) {
-    // Pretend the new area is allocated and then Delete() it to
-    // cause any necessary coalescing to occur.
-    //
-    // We do not adjust free_pages_ here since Delete() will do it for us.
-    Span* span = NewSpan(p, ask);
-    RecordSpan(span);
-    Delete(span);
-    ASSERT(Check());
-    return true;
-  } else {
-    // We could not allocate memory within "pagemap_"
-    // TODO: Once we can return memory to the system, return the new span
-    return false;
-  }
-}
-
-bool TCMalloc_PageHeap::Check() {
-#if USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
-  size_t totalFreeCommitted = 0;
-#endif
-  ASSERT(free_[0].normal.next(entropy_) == &free_[0].normal);
-  ASSERT(free_[0].returned.next(entropy_) == &free_[0].returned);
-#if USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
-  totalFreeCommitted = CheckList(&large_.normal, kMaxPages, 1000000000, false);
-#else
-  CheckList(&large_.normal, kMaxPages, 1000000000, false);
-#endif
-    CheckList(&large_.returned, kMaxPages, 1000000000, true);
-  for (Length s = 1; s < kMaxPages; s++) {
-#if USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
-    totalFreeCommitted += CheckList(&free_[s].normal, s, s, false);
-#else
-    CheckList(&free_[s].normal, s, s, false);
-#endif
-    CheckList(&free_[s].returned, s, s, true);
-  }
-#if USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
-  ASSERT(totalFreeCommitted == free_committed_pages_);
-#endif
-  return true;
-}
-
-#if ASSERT_DISABLED
-size_t TCMalloc_PageHeap::CheckList(Span*, Length, Length, bool) {
-  return 0;
-}
-#else
-size_t TCMalloc_PageHeap::CheckList(Span* list, Length min_pages, Length max_pages, bool decommitted) {
-  size_t freeCount = 0;
-  for (Span* s = list->next(entropy_); s != list; s = s->next(entropy_)) {
-    CHECK_CONDITION(s->free);
-    CHECK_CONDITION(s->length >= min_pages);
-    CHECK_CONDITION(s->length <= max_pages);
-    CHECK_CONDITION(GetDescriptor(s->start) == s);
-    CHECK_CONDITION(GetDescriptor(s->start+s->length-1) == s);
-    CHECK_CONDITION(s->decommitted == decommitted);
-    freeCount += s->length;
-  }
-  return freeCount;
-}
-#endif
-
-void TCMalloc_PageHeap::ReleaseFreeList(Span* list, Span* returned) {
-  // Walk backwards through list so that when we push these
-  // spans on the "returned" list, we preserve the order.
-#if USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
-  size_t freePageReduction = 0;
-#endif
-
-  while (!DLL_IsEmpty(list, entropy_)) {
-    Span* s = list->prev(entropy_);
-
-    DLL_Remove(s, entropy_);
-    s->decommitted = true;
-    DLL_Prepend(returned, s, entropy_);
-    TCMalloc_SystemRelease(reinterpret_cast<void*>(s->start << kPageShift),
-                           static_cast<size_t>(s->length << kPageShift));
-#if USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
-    freePageReduction += s->length;
-#endif
-  }
-
-#if USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
-    free_committed_pages_ -= freePageReduction;
-    if (free_committed_pages_ < min_free_committed_pages_since_last_scavenge_) 
-        min_free_committed_pages_since_last_scavenge_ = free_committed_pages_;
-#endif
-}
-
-void TCMalloc_PageHeap::ReleaseFreePages() {
-  for (Length s = 0; s < kMaxPages; s++) {
-    ReleaseFreeList(&free_[s].normal, &free_[s].returned);
-  }
-  ReleaseFreeList(&large_.normal, &large_.returned);
-  ASSERT(Check());
-}
-
-//-------------------------------------------------------------------
-// Free list
-//-------------------------------------------------------------------
-
-class TCMalloc_ThreadCache_FreeList {
- private:
-  HardenedSLL list_;       // Linked list of nodes
-  uint16_t length_;     // Current length
-  uint16_t lowater_;    // Low water mark for list length
-  uintptr_t entropy_;   // Entropy source for hardening
-
- public:
-  void Init(uintptr_t entropy) {
-    list_.setValue(NULL);
-    length_ = 0;
-    lowater_ = 0;
-    entropy_ = entropy;
-#if ENABLE(TCMALLOC_HARDENING)
-    ASSERT(entropy_);
-#endif
-  }
-
-  // Return current length of list
-  int length() const {
-    return length_;
-  }
-
-  // Is list empty?
-  bool empty() const {
-    return !list_;
-  }
-
-  // Low-water mark management
-  int lowwatermark() const { return lowater_; }
-  void clear_lowwatermark() { lowater_ = length_; }
-
-  ALWAYS_INLINE void Push(HardenedSLL ptr) {
-    SLL_Push(&list_, ptr, entropy_);
-    length_++;
-  }
-
-  void PushRange(int N, HardenedSLL start, HardenedSLL end) {
-    SLL_PushRange(&list_, start, end, entropy_);
-    length_ = length_ + static_cast<uint16_t>(N);
-  }
-
-  void PopRange(int N, HardenedSLL* start, HardenedSLL* end) {
-    SLL_PopRange(&list_, N, start, end, entropy_);
-    ASSERT(length_ >= N);
-    length_ = length_ - static_cast<uint16_t>(N);
-    if (length_ < lowater_) lowater_ = length_;
-  }
-
-  ALWAYS_INLINE void* Pop() {
-    ASSERT(list_);
-    length_--;
-    if (length_ < lowater_) lowater_ = length_;
-    return SLL_Pop(&list_, entropy_).value();
-  }
-
-    // Runs through the linked list to ensure that
-    // we can do that, and ensures that 'missing'
-    // is not present
-    NEVER_INLINE void Validate(HardenedSLL missing, size_t size) {
-        HardenedSLL node = list_;
-        UNUSED_PARAM(size);
-        while (node) {
-            RELEASE_ASSERT(node != missing);
-            RELEASE_ASSERT(IS_DEFINITELY_POISONED(node.value(), size));
-            node = SLL_Next(node, entropy_);
-        }
-    }
-
-#ifdef WTF_CHANGES
-  template <class Finder, class Reader>
-  void enumerateFreeObjects(Finder& finder, const Reader& reader)
-  {
-      for (HardenedSLL nextObject = list_; nextObject; nextObject.setValue(reader.nextEntryInHardenedLinkedList(reinterpret_cast<void**>(nextObject.value()), entropy_)))
-          finder.visit(nextObject.value());
-  }
-#endif
-};
-
-//-------------------------------------------------------------------
-// Data kept per thread
-//-------------------------------------------------------------------
-
-class TCMalloc_ThreadCache {
- private:
-  typedef TCMalloc_ThreadCache_FreeList FreeList;
-#if OS(WINDOWS)
-  typedef DWORD ThreadIdentifier;
-#else
-  typedef pthread_t ThreadIdentifier;
-#endif
-
-  size_t        size_;                  // Combined size of data
-  ThreadIdentifier tid_;                // Which thread owns it
-  bool          in_setspecific_;           // Called pthread_setspecific?
-  FreeList      list_[kNumClasses];     // Array indexed by size-class
-
-  // We sample allocations, biased by the size of the allocation
-  uint32_t      rnd_;                   // Cheap random number generator
-  size_t        bytes_until_sample_;    // Bytes until we sample next
-
-  uintptr_t     entropy_;               // Entropy value used for hardening
-
-  // Allocate a new heap. REQUIRES: pageheap_lock is held.
-  static inline TCMalloc_ThreadCache* NewHeap(ThreadIdentifier tid, uintptr_t entropy);
-
-  // Use only as pthread thread-specific destructor function.
-  static void DestroyThreadCache(void* ptr);
- public:
-  // All ThreadCache objects are kept in a linked list (for stats collection)
-  TCMalloc_ThreadCache* next_;
-  TCMalloc_ThreadCache* prev_;
-
-  void Init(ThreadIdentifier tid, uintptr_t entropy);
-  void Cleanup();
-
-  // Accessors (mostly just for printing stats)
-  int freelist_length(size_t cl) const { return list_[cl].length(); }
-
-  // Total byte size in cache
-  size_t Size() const { return size_; }
-
-  ALWAYS_INLINE void* Allocate(size_t size);
-  void Deallocate(HardenedSLL ptr, size_t size_class);
-
-  ALWAYS_INLINE void FetchFromCentralCache(size_t cl, size_t allocationSize);
-  void ReleaseToCentralCache(size_t cl, int N);
-  void Scavenge();
-  void Print() const;
-
-  // Record allocation of "k" bytes.  Return true iff allocation
-  // should be sampled
-  bool SampleAllocation(size_t k);
-
-  // Pick next sampling point
-  void PickNextSample(size_t k);
-
-  static void                  InitModule();
-  static void                  InitTSD();
-  static TCMalloc_ThreadCache* GetThreadHeap();
-  static TCMalloc_ThreadCache* GetCache();
-  static TCMalloc_ThreadCache* GetCacheIfPresent();
-  static TCMalloc_ThreadCache* CreateCacheIfNecessary();
-  static void                  DeleteCache(TCMalloc_ThreadCache* heap);
-  static void                  BecomeIdle();
-  static void                  RecomputeThreadCacheSize();
-
-#ifdef WTF_CHANGES
-  template <class Finder, class Reader>
-  void enumerateFreeObjects(Finder& finder, const Reader& reader)
-  {
-      for (unsigned sizeClass = 0; sizeClass < kNumClasses; sizeClass++)
-          list_[sizeClass].enumerateFreeObjects(finder, reader);
-  }
-#endif
-};
-
-//-------------------------------------------------------------------
-// Global variables
-//-------------------------------------------------------------------
-
-// Central cache -- a collection of free-lists, one per size-class.
-// We have a separate lock per free-list to reduce contention.
-static TCMalloc_Central_FreeListPadded central_cache[kNumClasses];
-
-// Page-level allocator
-static AllocAlignmentInteger pageheap_memory[(sizeof(TCMalloc_PageHeap) + sizeof(AllocAlignmentInteger) - 1) / sizeof(AllocAlignmentInteger)];
-static bool phinited = false;
-
-// Avoid extra level of indirection by making "pageheap" be just an alias
-// of pageheap_memory.
-typedef union {
-    void* m_memory;
-    TCMalloc_PageHeap* m_pageHeap;
-} PageHeapUnion;
-
-static inline TCMalloc_PageHeap* getPageHeap()
-{
-    PageHeapUnion u = { &pageheap_memory[0] };
-    return u.m_pageHeap;
-}
-
-#define pageheap getPageHeap()
-
-size_t fastMallocGoodSize(size_t bytes)
-{
-    if (!phinited)
-        TCMalloc_ThreadCache::InitModule();
-    return AllocationSize(bytes);
-}
-
-#if USE_BACKGROUND_THREAD_TO_SCAVENGE_MEMORY
-
-#if HAVE(DISPATCH_H) || OS(WINDOWS)
-
-void TCMalloc_PageHeap::periodicScavenge()
-{
-    SpinLockHolder h(&pageheap_lock);
-    pageheap->scavenge();
-
-    if (shouldScavenge()) {
-        rescheduleScavenger();
-        return;
-    }
-
-    suspendScavenger();
-}
-
-ALWAYS_INLINE void TCMalloc_PageHeap::signalScavenger()
-{
-    ASSERT(pageheap_lock.IsHeld());
-    if (isScavengerSuspended() && shouldScavenge())
-        scheduleScavenger();
-}
-
-#else
-
-void TCMalloc_PageHeap::scavengerThread()
-{
-#if HAVE(PTHREAD_SETNAME_NP)
-    pthread_setname_np("JavaScriptCore: FastMalloc scavenger");
-#endif
-
-    while (1) {
-        pageheap_lock.Lock();
-        if (!shouldScavenge()) {
-            // Set to false so that signalScavenger() will check whether we need to be siganlled.
-            m_scavengeThreadActive = false;
-
-            // We need to unlock now, as this thread will block on the condvar until scavenging is required.
-            pageheap_lock.Unlock();
-
-            // Block until there are enough free committed pages to release back to the system.
-            pthread_mutex_lock(&m_scavengeMutex);
-            pthread_cond_wait(&m_scavengeCondition, &m_scavengeMutex);
-            // After exiting the pthread_cond_wait, we hold the lock on m_scavengeMutex. Unlock it to prevent
-            // deadlock next time round the loop.
-            pthread_mutex_unlock(&m_scavengeMutex);
-
-            // Set to true to prevent unnecessary signalling of the condvar.
-            m_scavengeThreadActive = true;
-        } else
-            pageheap_lock.Unlock();
-
-        // Wait for a while to calculate how much memory remains unused during this pause.
-        sleep(kScavengeDelayInSeconds);
-
-        {
-            SpinLockHolder h(&pageheap_lock);
-            pageheap->scavenge();
-        }
-    }
-}
-
-#endif
-
-#endif
-
-// If TLS is available, we also store a copy
-// of the per-thread object in a __thread variable
-// since __thread variables are faster to read
-// than pthread_getspecific().  We still need
-// pthread_setspecific() because __thread
-// variables provide no way to run cleanup
-// code when a thread is destroyed.
-#ifdef HAVE_TLS
-static __thread TCMalloc_ThreadCache *threadlocal_heap;
-#endif
-// Thread-specific key.  Initialization here is somewhat tricky
-// because some Linux startup code invokes malloc() before it
-// is in a good enough state to handle pthread_keycreate().
-// Therefore, we use TSD keys only after tsd_inited is set to true.
-// Until then, we use a slow path to get the heap object.
-static bool tsd_inited = false;
-#if USE(PTHREAD_GETSPECIFIC_DIRECT)
-static const pthread_key_t heap_key = __PTK_FRAMEWORK_JAVASCRIPTCORE_KEY0;
-#else
-static pthread_key_t heap_key;
-#endif
-#if OS(WINDOWS)
-DWORD tlsIndex = TLS_OUT_OF_INDEXES;
-#endif
-
-static ALWAYS_INLINE void setThreadHeap(TCMalloc_ThreadCache* heap)
-{
-#if USE(PTHREAD_GETSPECIFIC_DIRECT)
-    // Can't have two libraries both doing this in the same process,
-    // so check and make this crash right away.
-    if (pthread_getspecific(heap_key))
-        CRASH();
-#endif
-
-    // Still do pthread_setspecific even if there's an alternate form
-    // of thread-local storage in use, to benefit from the delete callback.
-    pthread_setspecific(heap_key, heap);
-
-#if OS(WINDOWS)
-    TlsSetValue(tlsIndex, heap);
-#endif
-}
-
-// Allocator for thread heaps
-static PageHeapAllocator<TCMalloc_ThreadCache> threadheap_allocator;
-
-// Linked list of heap objects.  Protected by pageheap_lock.
-static TCMalloc_ThreadCache* thread_heaps = NULL;
-static int thread_heap_count = 0;
-
-// Overall thread cache size.  Protected by pageheap_lock.
-static size_t overall_thread_cache_size = kDefaultOverallThreadCacheSize;
-
-// Global per-thread cache size.  Writes are protected by
-// pageheap_lock.  Reads are done without any locking, which should be
-// fine as long as size_t can be written atomically and we don't place
-// invariants between this variable and other pieces of state.
-static volatile size_t per_thread_cache_size = kMaxThreadCacheSize;
-
-//-------------------------------------------------------------------
-// Central cache implementation
-//-------------------------------------------------------------------
-
-void TCMalloc_Central_FreeList::Init(size_t cl, uintptr_t entropy) {
-  lock_.Init();
-  size_class_ = cl;
-  entropy_ = entropy;
-#if ENABLE(TCMALLOC_HARDENING)
-  ASSERT(entropy_);
-#endif
-  DLL_Init(&empty_, entropy_);
-  DLL_Init(&nonempty_, entropy_);
-  counter_ = 0;
-
-  cache_size_ = 1;
-  used_slots_ = 0;
-  ASSERT(cache_size_ <= kNumTransferEntries);
-}
-
-void TCMalloc_Central_FreeList::ReleaseListToSpans(HardenedSLL start) {
-  while (start) {
-    HardenedSLL next = SLL_Next(start, entropy_);
-    ReleaseToSpans(start);
-    start = next;
-  }
-}
-
-ALWAYS_INLINE void TCMalloc_Central_FreeList::ReleaseToSpans(HardenedSLL object) {
-  const PageID p = reinterpret_cast<uintptr_t>(object.value()) >> kPageShift;
-  Span* span = pageheap->GetDescriptor(p);
-  ASSERT(span != NULL);
-  ASSERT(span->refcount > 0);
-
-  // If span is empty, move it to non-empty list
-  if (!span->objects) {
-    DLL_Remove(span, entropy_);
-    DLL_Prepend(&nonempty_, span, entropy_);
-    Event(span, 'N', 0);
-  }
-
-  // The following check is expensive, so it is disabled by default
-  if (false) {
-    // Check that object does not occur in list
-    unsigned got = 0;
-    for (HardenedSLL p = span->objects; !p; SLL_Next(p, entropy_)) {
-      ASSERT(p.value() != object.value());
-      got++;
-    }
-    ASSERT(got + span->refcount ==
-           (span->length<<kPageShift)/ByteSizeForClass(span->sizeclass));
-  }
-
-  counter_++;
-  span->refcount--;
-  if (span->refcount == 0) {
-    Event(span, '#', 0);
-    counter_ -= (span->length<<kPageShift) / ByteSizeForClass(span->sizeclass);
-    DLL_Remove(span, entropy_);
-
-    // Release central list lock while operating on pageheap
-    lock_.Unlock();
-    {
-      SpinLockHolder h(&pageheap_lock);
-      pageheap->Delete(span);
-    }
-    lock_.Lock();
-  } else {
-    SLL_SetNext(object, span->objects, entropy_);
-    span->objects.setValue(object.value());
-  }
-}
-
-ALWAYS_INLINE bool TCMalloc_Central_FreeList::EvictRandomSizeClass(
-    size_t locked_size_class, bool force) {
-  static int race_counter = 0;
-  int t = race_counter++;  // Updated without a lock, but who cares.
-  if (t >= static_cast<int>(kNumClasses)) {
-    while (t >= static_cast<int>(kNumClasses)) {
-      t -= kNumClasses;
-    }
-    race_counter = t;
-  }
-  ASSERT(t >= 0);
-  ASSERT(t < static_cast<int>(kNumClasses));
-  if (t == static_cast<int>(locked_size_class)) return false;
-  return central_cache[t].ShrinkCache(static_cast<int>(locked_size_class), force);
-}
-
-bool TCMalloc_Central_FreeList::MakeCacheSpace() {
-  // Is there room in the cache?
-  if (used_slots_ < cache_size_) return true;
-  // Check if we can expand this cache?
-  if (cache_size_ == kNumTransferEntries) return false;
-  // Ok, we'll try to grab an entry from some other size class.
-  if (EvictRandomSizeClass(size_class_, false) ||
-      EvictRandomSizeClass(size_class_, true)) {
-    // Succeeded in evicting, we're going to make our cache larger.
-    cache_size_++;
-    return true;
-  }
-  return false;
-}
-
-
-namespace {
-class LockInverter {
- private:
-  SpinLock *held_, *temp_;
- public:
-  inline explicit LockInverter(SpinLock* held, SpinLock *temp)
-    : held_(held), temp_(temp) { held_->Unlock(); temp_->Lock(); }
-  inline ~LockInverter() { temp_->Unlock(); held_->Lock();  }
-};
-}
-
-bool TCMalloc_Central_FreeList::ShrinkCache(int locked_size_class, bool force) {
-  // Start with a quick check without taking a lock.
-  if (cache_size_ == 0) return false;
-  // We don't evict from a full cache unless we are 'forcing'.
-  if (force == false && used_slots_ == cache_size_) return false;
-
-  // Grab lock, but first release the other lock held by this thread.  We use
-  // the lock inverter to ensure that we never hold two size class locks
-  // concurrently.  That can create a deadlock because there is no well
-  // defined nesting order.
-  LockInverter li(&central_cache[locked_size_class].lock_, &lock_);
-  ASSERT(used_slots_ <= cache_size_);
-  ASSERT(0 <= cache_size_);
-  if (cache_size_ == 0) return false;
-  if (used_slots_ == cache_size_) {
-    if (force == false) return false;
-    // ReleaseListToSpans releases the lock, so we have to make all the
-    // updates to the central list before calling it.
-    cache_size_--;
-    used_slots_--;
-    ReleaseListToSpans(tc_slots_[used_slots_].head);
-    return true;
-  }
-  cache_size_--;
-  return true;
-}
-
-void TCMalloc_Central_FreeList::InsertRange(HardenedSLL start, HardenedSLL end, int N) {
-  SpinLockHolder h(&lock_);
-  if (N == num_objects_to_move[size_class_] &&
-    MakeCacheSpace()) {
-    int slot = used_slots_++;
-    ASSERT(slot >=0);
-    ASSERT(slot < kNumTransferEntries);
-    TCEntry *entry = &tc_slots_[slot];
-    entry->head = start;
-    entry->tail = end;
-    return;
-  }
-  ReleaseListToSpans(start);
-}
-
-void TCMalloc_Central_FreeList::RemoveRange(HardenedSLL* start, HardenedSLL* end, int *N) {
-  int num = *N;
-  ASSERT(num > 0);
-
-  SpinLockHolder h(&lock_);
-  if (num == num_objects_to_move[size_class_] && used_slots_ > 0) {
-    int slot = --used_slots_;
-    ASSERT(slot >= 0);
-    TCEntry *entry = &tc_slots_[slot];
-    *start = entry->head;
-    *end = entry->tail;
-    return;
-  }
-
-  // TODO: Prefetch multiple TCEntries?
-  HardenedSLL tail = FetchFromSpansSafe();
-  if (!tail) {
-    // We are completely out of memory.
-    *start = *end = HardenedSLL::null();
-    *N = 0;
-    return;
-  }
-
-  SLL_SetNext(tail, HardenedSLL::null(), entropy_);
-  HardenedSLL head = tail;
-  int count = 1;
-  while (count < num) {
-    HardenedSLL t = FetchFromSpans();
-    if (!t) break;
-    SLL_Push(&head, t, entropy_);
-    count++;
-  }
-  *start = head;
-  *end = tail;
-  *N = count;
-}
-
-
-HardenedSLL TCMalloc_Central_FreeList::FetchFromSpansSafe() {
-  HardenedSLL t = FetchFromSpans();
-  if (!t) {
-    Populate();
-    t = FetchFromSpans();
-  }
-  return t;
-}
-
-HardenedSLL TCMalloc_Central_FreeList::FetchFromSpans() {
-  if (DLL_IsEmpty(&nonempty_, entropy_)) return HardenedSLL::null();
-  Span* span = nonempty_.next(entropy_);
-
-  ASSERT(span->objects);
-  ASSERT_SPAN_COMMITTED(span);
-  span->refcount++;
-  HardenedSLL result = span->objects;
-  span->objects = SLL_Next(result, entropy_);
-  if (!span->objects) {
-    // Move to empty list
-    DLL_Remove(span, entropy_);
-    DLL_Prepend(&empty_, span, entropy_);
-    Event(span, 'E', 0);
-  }
-  counter_--;
-  return result;
-}
-
-// Fetch memory from the system and add to the central cache freelist.
-ALWAYS_INLINE void TCMalloc_Central_FreeList::Populate() {
-  // Release central list lock while operating on pageheap
-  lock_.Unlock();
-  const size_t npages = class_to_pages[size_class_];
-
-  Span* span;
-  {
-    SpinLockHolder h(&pageheap_lock);
-    span = pageheap->New(npages);
-    if (span) pageheap->RegisterSizeClass(span, size_class_);
-  }
-  if (span == NULL) {
-#if HAVE(ERRNO_H)
-    MESSAGE("allocation failed: %d\n", errno);
-#elif OS(WINDOWS)
-    MESSAGE("allocation failed: %d\n", ::GetLastError());
-#else
-    MESSAGE("allocation failed\n");
-#endif
-    lock_.Lock();
-    return;
-  }
-  ASSERT_SPAN_COMMITTED(span);
-  ASSERT(span->length == npages);
-  // Cache sizeclass info eagerly.  Locking is not necessary.
-  // (Instead of being eager, we could just replace any stale info
-  // about this span, but that seems to be no better in practice.)
-  for (size_t i = 0; i < npages; i++) {
-    pageheap->CacheSizeClass(span->start + i, size_class_);
-  }
-
-  // Split the block into pieces and add to the free-list
-  // TODO: coloring of objects to avoid cache conflicts?
-  HardenedSLL head = HardenedSLL::null();
-  char* start = reinterpret_cast<char*>(span->start << kPageShift);
-  const size_t size = ByteSizeForClass(size_class_);
-  char* ptr = start + (npages << kPageShift) - ((npages << kPageShift) % size);
-  int num = 0;
-#if ENABLE(TCMALLOC_HARDENING)
-  uint32_t startPoison = freedObjectStartPoison();
-  uint32_t endPoison = freedObjectEndPoison();
-#endif
-
-  while (ptr > start) {
-    ptr -= size;
-    HardenedSLL node = HardenedSLL::create(ptr);
-    POISON_DEALLOCATION_EXPLICIT(ptr, size, startPoison, endPoison);
-    SLL_SetNext(node, head, entropy_);
-    head = node;
-    num++;
-  }
-  ASSERT(ptr == start);
-  ASSERT(ptr == head.value());
-#ifndef NDEBUG
-    {
-        HardenedSLL node = head;
-        while (node) {
-            ASSERT(IS_DEFINITELY_POISONED(node.value(), size));
-            node = SLL_Next(node, entropy_);
-        }
-    }
-#endif
-  span->objects = head;
-  ASSERT(span->objects.value() == head.value());
-  span->refcount = 0; // No sub-object in use yet
-
-  // Add span to list of non-empty spans
-  lock_.Lock();
-  DLL_Prepend(&nonempty_, span, entropy_);
-  counter_ += num;
-}
-
-//-------------------------------------------------------------------
-// TCMalloc_ThreadCache implementation
-//-------------------------------------------------------------------
-
-inline bool TCMalloc_ThreadCache::SampleAllocation(size_t k) {
-  if (bytes_until_sample_ < k) {
-    PickNextSample(k);
-    return true;
-  } else {
-    bytes_until_sample_ -= k;
-    return false;
-  }
-}
-
-void TCMalloc_ThreadCache::Init(ThreadIdentifier tid, uintptr_t entropy) {
-  size_ = 0;
-  next_ = NULL;
-  prev_ = NULL;
-  tid_  = tid;
-  in_setspecific_ = false;
-  entropy_ = entropy;
-#if ENABLE(TCMALLOC_HARDENING)
-  ASSERT(entropy_);
-#endif
-  for (size_t cl = 0; cl < kNumClasses; ++cl) {
-    list_[cl].Init(entropy_);
-  }
-
-  // Initialize RNG -- run it for a bit to get to good values
-  bytes_until_sample_ = 0;
-  rnd_ = static_cast<uint32_t>(reinterpret_cast<uintptr_t>(this));
-  for (int i = 0; i < 100; i++) {
-    PickNextSample(static_cast<size_t>(FLAGS_tcmalloc_sample_parameter * 2));
-  }
-}
-
-void TCMalloc_ThreadCache::Cleanup() {
-  // Put unused memory back into central cache
-  for (size_t cl = 0; cl < kNumClasses; ++cl) {
-    if (list_[cl].length() > 0) {
-      ReleaseToCentralCache(cl, list_[cl].length());
-    }
-  }
-}
-
-ALWAYS_INLINE void* TCMalloc_ThreadCache::Allocate(size_t size) {
-  ASSERT(size <= kMaxSize);
-  const size_t cl = SizeClass(size);
-  FreeList* list = &list_[cl];
-  size_t allocationSize = ByteSizeForClass(cl);
-  if (list->empty()) {
-    FetchFromCentralCache(cl, allocationSize);
-    if (list->empty()) return NULL;
-  }
-  size_ -= allocationSize;
-  void* result = list->Pop();
-  if (!result)
-      return 0;
-  RELEASE_ASSERT(IS_DEFINITELY_POISONED(result, allocationSize));
-  POISON_ALLOCATION(result, allocationSize);
-  return result;
-}
-
-inline void TCMalloc_ThreadCache::Deallocate(HardenedSLL ptr, size_t cl) {
-  size_t allocationSize = ByteSizeForClass(cl);
-  size_ += allocationSize;
-  FreeList* list = &list_[cl];
-  if (MAY_BE_POISONED(ptr.value(), allocationSize))
-      list->Validate(ptr, allocationSize);
-
-  POISON_DEALLOCATION(ptr.value(), allocationSize);
-  list->Push(ptr);
-  // If enough data is free, put back into central cache
-  if (list->length() > kMaxFreeListLength) {
-    ReleaseToCentralCache(cl, num_objects_to_move[cl]);
-  }
-  if (size_ >= per_thread_cache_size) Scavenge();
-}
-
-// Remove some objects of class "cl" from central cache and add to thread heap
-ALWAYS_INLINE void TCMalloc_ThreadCache::FetchFromCentralCache(size_t cl, size_t allocationSize) {
-  int fetch_count = num_objects_to_move[cl];
-  HardenedSLL start, end;
-  central_cache[cl].RemoveRange(&start, &end, &fetch_count);
-  list_[cl].PushRange(fetch_count, start, end);
-  size_ += allocationSize * fetch_count;
-}
-
-// Remove some objects of class "cl" from thread heap and add to central cache
-inline void TCMalloc_ThreadCache::ReleaseToCentralCache(size_t cl, int N) {
-  ASSERT(N > 0);
-  FreeList* src = &list_[cl];
-  if (N > src->length()) N = src->length();
-  size_ -= N*ByteSizeForClass(cl);
-
-  // We return prepackaged chains of the correct size to the central cache.
-  // TODO: Use the same format internally in the thread caches?
-  int batch_size = num_objects_to_move[cl];
-  while (N > batch_size) {
-    HardenedSLL tail, head;
-    src->PopRange(batch_size, &head, &tail);
-    central_cache[cl].InsertRange(head, tail, batch_size);
-    N -= batch_size;
-  }
-  HardenedSLL tail, head;
-  src->PopRange(N, &head, &tail);
-  central_cache[cl].InsertRange(head, tail, N);
-}
-
-// Release idle memory to the central cache
-inline void TCMalloc_ThreadCache::Scavenge() {
-  // If the low-water mark for the free list is L, it means we would
-  // not have had to allocate anything from the central cache even if
-  // we had reduced the free list size by L.  We aim to get closer to
-  // that situation by dropping L/2 nodes from the free list.  This
-  // may not release much memory, but if so we will call scavenge again
-  // pretty soon and the low-water marks will be high on that call.
-  //int64 start = CycleClock::Now();
-
-  for (size_t cl = 0; cl < kNumClasses; cl++) {
-    FreeList* list = &list_[cl];
-    const int lowmark = list->lowwatermark();
-    if (lowmark > 0) {
-      const int drop = (lowmark > 1) ? lowmark/2 : 1;
-      ReleaseToCentralCache(cl, drop);
-    }
-    list->clear_lowwatermark();
-  }
-
-  //int64 finish = CycleClock::Now();
-  //CycleTimer ct;
-  //MESSAGE("GC: %.0f ns\n", ct.CyclesToUsec(finish-start)*1000.0);
-}
-
-void TCMalloc_ThreadCache::PickNextSample(size_t k) {
-  // Make next "random" number
-  // x^32+x^22+x^2+x^1+1 is a primitive polynomial for random numbers
-  static const uint32_t kPoly = (1 << 22) | (1 << 2) | (1 << 1) | (1 << 0);
-  uint32_t r = rnd_;
-  rnd_ = (r << 1) ^ ((static_cast<int32_t>(r) >> 31) & kPoly);
-
-  // Next point is "rnd_ % (sample_period)".  I.e., average
-  // increment is "sample_period/2".
-  const int flag_value = static_cast<int>(FLAGS_tcmalloc_sample_parameter);
-  static int last_flag_value = -1;
-
-  if (flag_value != last_flag_value) {
-    SpinLockHolder h(&sample_period_lock);
-    int i;
-    for (i = 0; i < (static_cast<int>(sizeof(primes_list)/sizeof(primes_list[0])) - 1); i++) {
-      if (primes_list[i] >= flag_value) {
-        break;
-      }
-    }
-    sample_period = primes_list[i];
-    last_flag_value = flag_value;
-  }
-
-  bytes_until_sample_ += rnd_ % sample_period;
-
-  if (k > (static_cast<size_t>(-1) >> 2)) {
-    // If the user has asked for a huge allocation then it is possible
-    // for the code below to loop infinitely.  Just return (note that
-    // this throws off the sampling accuracy somewhat, but a user who
-    // is allocating more than 1G of memory at a time can live with a
-    // minor inaccuracy in profiling of small allocations, and also
-    // would rather not wait for the loop below to terminate).
-    return;
-  }
-
-  while (bytes_until_sample_ < k) {
-    // Increase bytes_until_sample_ by enough average sampling periods
-    // (sample_period >> 1) to allow us to sample past the current
-    // allocation.
-    bytes_until_sample_ += (sample_period >> 1);
-  }
-
-  bytes_until_sample_ -= k;
-}
-
-void TCMalloc_ThreadCache::InitModule() {
-  // There is a slight potential race here because of double-checked
-  // locking idiom.  However, as long as the program does a small
-  // allocation before switching to multi-threaded mode, we will be
-  // fine.  We increase the chances of doing such a small allocation
-  // by doing one in the constructor of the module_enter_exit_hook
-  // object declared below.
-  SpinLockHolder h(&pageheap_lock);
-  if (!phinited) {
-    uintptr_t entropy = HARDENING_ENTROPY;
-#ifdef WTF_CHANGES
-    InitTSD();
-#endif
-    InitSizeClasses();
-    threadheap_allocator.Init(entropy);
-    span_allocator.Init(entropy);
-    span_allocator.New(); // Reduce cache conflicts
-    span_allocator.New(); // Reduce cache conflicts
-    stacktrace_allocator.Init(entropy);
-    DLL_Init(&sampled_objects, entropy);
-    for (size_t i = 0; i < kNumClasses; ++i) {
-      central_cache[i].Init(i, entropy);
-    }
-    pageheap->init();
-    phinited = 1;
-#if defined(WTF_CHANGES) && OS(DARWIN)
-    FastMallocZone::init();
-#endif
-  }
-}
-
-inline TCMalloc_ThreadCache* TCMalloc_ThreadCache::NewHeap(ThreadIdentifier tid, uintptr_t entropy) {
-  // Create the heap and add it to the linked list
-  TCMalloc_ThreadCache *heap = threadheap_allocator.New();
-  heap->Init(tid, entropy);
-  heap->next_ = thread_heaps;
-  heap->prev_ = NULL;
-  if (thread_heaps != NULL) thread_heaps->prev_ = heap;
-  thread_heaps = heap;
-  thread_heap_count++;
-  RecomputeThreadCacheSize();
-  return heap;
-}
-
-inline TCMalloc_ThreadCache* TCMalloc_ThreadCache::GetThreadHeap() {
-#ifdef HAVE_TLS
-    // __thread is faster, but only when the kernel supports it
-  if (KernelSupportsTLS())
-    return threadlocal_heap;
-#elif OS(WINDOWS)
-    return static_cast<TCMalloc_ThreadCache*>(TlsGetValue(tlsIndex));
-#else
-    return static_cast<TCMalloc_ThreadCache*>(pthread_getspecific(heap_key));
-#endif
-}
-
-inline TCMalloc_ThreadCache* TCMalloc_ThreadCache::GetCache() {
-  TCMalloc_ThreadCache* ptr = NULL;
-  if (!tsd_inited) {
-    InitModule();
-  } else {
-    ptr = GetThreadHeap();
-  }
-  if (ptr == NULL) ptr = CreateCacheIfNecessary();
-  return ptr;
-}
-
-// In deletion paths, we do not try to create a thread-cache.  This is
-// because we may be in the thread destruction code and may have
-// already cleaned up the cache for this thread.
-inline TCMalloc_ThreadCache* TCMalloc_ThreadCache::GetCacheIfPresent() {
-  if (!tsd_inited) return NULL;
-  void* const p = GetThreadHeap();
-  return reinterpret_cast<TCMalloc_ThreadCache*>(p);
-}
-
-void TCMalloc_ThreadCache::InitTSD() {
-  ASSERT(!tsd_inited);
-#if USE(PTHREAD_GETSPECIFIC_DIRECT)
-  pthread_key_init_np(heap_key, DestroyThreadCache);
-#else
-  pthread_key_create(&heap_key, DestroyThreadCache);
-#endif
-#if OS(WINDOWS)
-  tlsIndex = TlsAlloc();
-#endif
-  tsd_inited = true;
-    
-#if !OS(WINDOWS)
-  // We may have used a fake pthread_t for the main thread.  Fix it.
-  pthread_t zero;
-  memset(&zero, 0, sizeof(zero));
-#endif
-#ifndef WTF_CHANGES
-  SpinLockHolder h(&pageheap_lock);
-#else
-  ASSERT(pageheap_lock.IsHeld());
-#endif
-  for (TCMalloc_ThreadCache* h = thread_heaps; h != NULL; h = h->next_) {
-#if OS(WINDOWS)
-    if (h->tid_ == 0) {
-      h->tid_ = GetCurrentThreadId();
-    }
-#else
-    if (pthread_equal(h->tid_, zero)) {
-      h->tid_ = pthread_self();
-    }
-#endif
-  }
-}
-
-TCMalloc_ThreadCache* TCMalloc_ThreadCache::CreateCacheIfNecessary() {
-  // Initialize per-thread data if necessary
-  TCMalloc_ThreadCache* heap = NULL;
-  {
-    SpinLockHolder h(&pageheap_lock);
-
-#if OS(WINDOWS)
-    DWORD me;
-    if (!tsd_inited) {
-      me = 0;
-    } else {
-      me = GetCurrentThreadId();
-    }
-#else
-    // Early on in glibc's life, we cannot even call pthread_self()
-    pthread_t me;
-    if (!tsd_inited) {
-      memset(&me, 0, sizeof(me));
-    } else {
-      me = pthread_self();
-    }
-#endif
-
-    // This may be a recursive malloc call from pthread_setspecific()
-    // In that case, the heap for this thread has already been created
-    // and added to the linked list.  So we search for that first.
-    for (TCMalloc_ThreadCache* h = thread_heaps; h != NULL; h = h->next_) {
-#if OS(WINDOWS)
-      if (h->tid_ == me) {
-#else
-      if (pthread_equal(h->tid_, me)) {
-#endif
-        heap = h;
-        break;
-      }
-    }
-
-    if (heap == NULL) heap = NewHeap(me, HARDENING_ENTROPY);
-  }
-
-  // We call pthread_setspecific() outside the lock because it may
-  // call malloc() recursively.  The recursive call will never get
-  // here again because it will find the already allocated heap in the
-  // linked list of heaps.
-  if (!heap->in_setspecific_ && tsd_inited) {
-    heap->in_setspecific_ = true;
-    setThreadHeap(heap);
-  }
-  return heap;
-}
-
-void TCMalloc_ThreadCache::BecomeIdle() {
-  if (!tsd_inited) return;              // No caches yet
-  TCMalloc_ThreadCache* heap = GetThreadHeap();
-  if (heap == NULL) return;             // No thread cache to remove
-  if (heap->in_setspecific_) return;    // Do not disturb the active caller
-
-  heap->in_setspecific_ = true;
-  setThreadHeap(NULL);
-#ifdef HAVE_TLS
-  // Also update the copy in __thread
-  threadlocal_heap = NULL;
-#endif
-  heap->in_setspecific_ = false;
-  if (GetThreadHeap() == heap) {
-    // Somehow heap got reinstated by a recursive call to malloc
-    // from pthread_setspecific.  We give up in this case.
-    return;
-  }
-
-  // We can now get rid of the heap
-  DeleteCache(heap);
-}
-
-void TCMalloc_ThreadCache::DestroyThreadCache(void* ptr) {
-  // Note that "ptr" cannot be NULL since pthread promises not
-  // to invoke the destructor on NULL values, but for safety,
-  // we check anyway.
-  if (ptr == NULL) return;
-#ifdef HAVE_TLS
-  // Prevent fast path of GetThreadHeap() from returning heap.
-  threadlocal_heap = NULL;
-#endif
-  DeleteCache(reinterpret_cast<TCMalloc_ThreadCache*>(ptr));
-}
-
-void TCMalloc_ThreadCache::DeleteCache(TCMalloc_ThreadCache* heap) {
-  // Remove all memory from heap
-  heap->Cleanup();
-
-  // Remove from linked list
-  SpinLockHolder h(&pageheap_lock);
-  if (heap->next_ != NULL) heap->next_->prev_ = heap->prev_;
-  if (heap->prev_ != NULL) heap->prev_->next_ = heap->next_;
-  if (thread_heaps == heap) thread_heaps = heap->next_;
-  thread_heap_count--;
-  RecomputeThreadCacheSize();
-
-  threadheap_allocator.Delete(heap);
-}
-
-void TCMalloc_ThreadCache::RecomputeThreadCacheSize() {
-  // Divide available space across threads
-  int n = thread_heap_count > 0 ? thread_heap_count : 1;
-  size_t space = overall_thread_cache_size / n;
-
-  // Limit to allowed range
-  if (space < kMinThreadCacheSize) space = kMinThreadCacheSize;
-  if (space > kMaxThreadCacheSize) space = kMaxThreadCacheSize;
-
-  per_thread_cache_size = space;
-}
-
-void TCMalloc_ThreadCache::Print() const {
-  for (size_t cl = 0; cl < kNumClasses; ++cl) {
-    MESSAGE("      %5" PRIuS " : %4d len; %4d lo\n",
-            ByteSizeForClass(cl),
-            list_[cl].length(),
-            list_[cl].lowwatermark());
-  }
-}
-
-// Extract interesting stats
-struct TCMallocStats {
-  uint64_t system_bytes;        // Bytes alloced from system
-  uint64_t thread_bytes;        // Bytes in thread caches
-  uint64_t central_bytes;       // Bytes in central cache
-  uint64_t transfer_bytes;      // Bytes in central transfer cache
-  uint64_t pageheap_bytes;      // Bytes in page heap
-  uint64_t metadata_bytes;      // Bytes alloced for metadata
-};
-
-#ifndef WTF_CHANGES
-// Get stats into "r".  Also get per-size-class counts if class_count != NULL
-static void ExtractStats(TCMallocStats* r, uint64_t* class_count) {
-  r->central_bytes = 0;
-  r->transfer_bytes = 0;
-  for (int cl = 0; cl < kNumClasses; ++cl) {
-    const int length = central_cache[cl].length();
-    const int tc_length = central_cache[cl].tc_length();
-    r->central_bytes += static_cast<uint64_t>(ByteSizeForClass(cl)) * length;
-    r->transfer_bytes +=
-      static_cast<uint64_t>(ByteSizeForClass(cl)) * tc_length;
-    if (class_count) class_count[cl] = length + tc_length;
-  }
-
-  // Add stats from per-thread heaps
-  r->thread_bytes = 0;
-  { // scope
-    SpinLockHolder h(&pageheap_lock);
-    for (TCMalloc_ThreadCache* h = thread_heaps; h != NULL; h = h->next_) {
-      r->thread_bytes += h->Size();
-      if (class_count) {
-        for (size_t cl = 0; cl < kNumClasses; ++cl) {
-          class_count[cl] += h->freelist_length(cl);
-        }
-      }
-    }
-  }
-
-  { //scope
-    SpinLockHolder h(&pageheap_lock);
-    r->system_bytes = pageheap->SystemBytes();
-    r->metadata_bytes = metadata_system_bytes;
-    r->pageheap_bytes = pageheap->FreeBytes();
-  }
-}
-#endif
-
-#ifndef WTF_CHANGES
-// WRITE stats to "out"
-static void DumpStats(TCMalloc_Printer* out, int level) {
-  TCMallocStats stats;
-  uint64_t class_count[kNumClasses];
-  ExtractStats(&stats, (level >= 2 ? class_count : NULL));
-
-  if (level >= 2) {
-    out->printf("------------------------------------------------\n");
-    uint64_t cumulative = 0;
-    for (int cl = 0; cl < kNumClasses; ++cl) {
-      if (class_count[cl] > 0) {
-        uint64_t class_bytes = class_count[cl] * ByteSizeForClass(cl);
-        cumulative += class_bytes;
-        out->printf("class %3d [ %8" PRIuS " bytes ] : "
-                "%8" PRIu64 " objs; %5.1f MB; %5.1f cum MB\n",
-                cl, ByteSizeForClass(cl),
-                class_count[cl],
-                class_bytes / 1048576.0,
-                cumulative / 1048576.0);
-      }
-    }
-
-    SpinLockHolder h(&pageheap_lock);
-    pageheap->Dump(out);
-  }
-
-  const uint64_t bytes_in_use = stats.system_bytes
-                                - stats.pageheap_bytes
-                                - stats.central_bytes
-                                - stats.transfer_bytes
-                                - stats.thread_bytes;
-
-  out->printf("------------------------------------------------\n"
-              "MALLOC: %12" PRIu64 " Heap size\n"
-              "MALLOC: %12" PRIu64 " Bytes in use by application\n"
-              "MALLOC: %12" PRIu64 " Bytes free in page heap\n"
-              "MALLOC: %12" PRIu64 " Bytes free in central cache\n"
-              "MALLOC: %12" PRIu64 " Bytes free in transfer cache\n"
-              "MALLOC: %12" PRIu64 " Bytes free in thread caches\n"
-              "MALLOC: %12" PRIu64 " Spans in use\n"
-              "MALLOC: %12" PRIu64 " Thread heaps in use\n"
-              "MALLOC: %12" PRIu64 " Metadata allocated\n"
-              "------------------------------------------------\n",
-              stats.system_bytes,
-              bytes_in_use,
-              stats.pageheap_bytes,
-              stats.central_bytes,
-              stats.transfer_bytes,
-              stats.thread_bytes,
-              uint64_t(span_allocator.inuse()),
-              uint64_t(threadheap_allocator.inuse()),
-              stats.metadata_bytes);
-}
-
-static void PrintStats(int level) {
-  const int kBufferSize = 16 << 10;
-  char* buffer = new char[kBufferSize];
-  TCMalloc_Printer printer(buffer, kBufferSize);
-  DumpStats(&printer, level);
-  write(STDERR_FILENO, buffer, strlen(buffer));
-  delete[] buffer;
-}
-
-static void** DumpStackTraces() {
-  // Count how much space we need
-  int needed_slots = 0;
-  {
-    SpinLockHolder h(&pageheap_lock);
-    for (Span* s = sampled_objects.next; s != &sampled_objects; s = s->next) {
-      StackTrace* stack = reinterpret_cast<StackTrace*>(s->objects);
-      needed_slots += 3 + stack->depth;
-    }
-    needed_slots += 100;            // Slop in case sample grows
-    needed_slots += needed_slots/8; // An extra 12.5% slop
-  }
-
-  void** result = new void*[needed_slots];
-  if (result == NULL) {
-    MESSAGE("tcmalloc: could not allocate %d slots for stack traces\n",
-            needed_slots);
-    return NULL;
-  }
-
-  SpinLockHolder h(&pageheap_lock);
-  int used_slots = 0;
-  for (Span* s = sampled_objects.next; s != &sampled_objects; s = s->next) {
-    ASSERT(used_slots < needed_slots);  // Need to leave room for terminator
-    StackTrace* stack = reinterpret_cast<StackTrace*>(s->objects);
-    if (used_slots + 3 + stack->depth >= needed_slots) {
-      // No more room
-      break;
-    }
-
-    result[used_slots+0] = reinterpret_cast<void*>(static_cast<uintptr_t>(1));
-    result[used_slots+1] = reinterpret_cast<void*>(stack->size);
-    result[used_slots+2] = reinterpret_cast<void*>(stack->depth);
-    for (int d = 0; d < stack->depth; d++) {
-      result[used_slots+3+d] = stack->stack[d];
-    }
-    used_slots += 3 + stack->depth;
-  }
-  result[used_slots] = reinterpret_cast<void*>(static_cast<uintptr_t>(0));
-  return result;
-}
-#endif
-
-#ifndef WTF_CHANGES
-
-// TCMalloc's support for extra malloc interfaces
-class TCMallocImplementation : public MallocExtension {
- public:
-  virtual void GetStats(char* buffer, int buffer_length) {
-    ASSERT(buffer_length > 0);
-    TCMalloc_Printer printer(buffer, buffer_length);
-
-    // Print level one stats unless lots of space is available
-    if (buffer_length < 10000) {
-      DumpStats(&printer, 1);
-    } else {
-      DumpStats(&printer, 2);
-    }
-  }
-
-  virtual void** ReadStackTraces() {
-    return DumpStackTraces();
-  }
-
-  virtual bool GetNumericProperty(const char* name, size_t* value) {
-    ASSERT(name != NULL);
-
-    if (strcmp(name, "generic.current_allocated_bytes") == 0) {
-      TCMallocStats stats;
-      ExtractStats(&stats, NULL);
-      *value = stats.system_bytes
-               - stats.thread_bytes
-               - stats.central_bytes
-               - stats.pageheap_bytes;
-      return true;
-    }
-
-    if (strcmp(name, "generic.heap_size") == 0) {
-      TCMallocStats stats;
-      ExtractStats(&stats, NULL);
-      *value = stats.system_bytes;
-      return true;
-    }
-
-    if (strcmp(name, "tcmalloc.slack_bytes") == 0) {
-      // We assume that bytes in the page heap are not fragmented too
-      // badly, and are therefore available for allocation.
-      SpinLockHolder l(&pageheap_lock);
-      *value = pageheap->FreeBytes();
-      return true;
-    }
-
-    if (strcmp(name, "tcmalloc.max_total_thread_cache_bytes") == 0) {
-      SpinLockHolder l(&pageheap_lock);
-      *value = overall_thread_cache_size;
-      return true;
-    }
-
-    if (strcmp(name, "tcmalloc.current_total_thread_cache_bytes") == 0) {
-      TCMallocStats stats;
-      ExtractStats(&stats, NULL);
-      *value = stats.thread_bytes;
-      return true;
-    }
-
-    return false;
-  }
-
-  virtual bool SetNumericProperty(const char* name, size_t value) {
-    ASSERT(name != NULL);
-
-    if (strcmp(name, "tcmalloc.max_total_thread_cache_bytes") == 0) {
-      // Clip the value to a reasonable range
-      if (value < kMinThreadCacheSize) value = kMinThreadCacheSize;
-      if (value > (1<<30)) value = (1<<30);     // Limit to 1GB
-
-      SpinLockHolder l(&pageheap_lock);
-      overall_thread_cache_size = static_cast<size_t>(value);
-      TCMalloc_ThreadCache::RecomputeThreadCacheSize();
-      return true;
-    }
-
-    return false;
-  }
-
-  virtual void MarkThreadIdle() {
-    TCMalloc_ThreadCache::BecomeIdle();
-  }
-
-  virtual void ReleaseFreeMemory() {
-    SpinLockHolder h(&pageheap_lock);
-    pageheap->ReleaseFreePages();
-  }
-};
-#endif
-
-// The constructor allocates an object to ensure that initialization
-// runs before main(), and therefore we do not have a chance to become
-// multi-threaded before initialization.  We also create the TSD key
-// here.  Presumably by the time this constructor runs, glibc is in
-// good enough shape to handle pthread_key_create().
-//
-// The constructor also takes the opportunity to tell STL to use
-// tcmalloc.  We want to do this early, before construct time, so
-// all user STL allocations go through tcmalloc (which works really
-// well for STL).
-//
-// The destructor prints stats when the program exits.
-class TCMallocGuard {
- public:
-
-  TCMallocGuard() {
-#ifdef HAVE_TLS    // this is true if the cc/ld/libc combo support TLS
-    // Check whether the kernel also supports TLS (needs to happen at runtime)
-    CheckIfKernelSupportsTLS();
-#endif
-#ifndef WTF_CHANGES
-#ifdef WIN32                    // patch the windows VirtualAlloc, etc.
-    PatchWindowsFunctions();    // defined in windows/patch_functions.cc
-#endif
-#endif
-    free(malloc(1));
-    TCMalloc_ThreadCache::InitTSD();
-    free(malloc(1));
-#ifndef WTF_CHANGES
-    MallocExtension::Register(new TCMallocImplementation);
-#endif
-  }
-
-#ifndef WTF_CHANGES
-  ~TCMallocGuard() {
-    const char* env = getenv("MALLOCSTATS");
-    if (env != NULL) {
-      int level = atoi(env);
-      if (level < 1) level = 1;
-      PrintStats(level);
-    }
-#ifdef WIN32
-    UnpatchWindowsFunctions();
-#endif
-  }
-#endif
-};
-
-#ifndef WTF_CHANGES
-static TCMallocGuard module_enter_exit_hook;
-#endif
-
-
-//-------------------------------------------------------------------
-// Helpers for the exported routines below
-//-------------------------------------------------------------------
-
-#ifndef WTF_CHANGES
-
-static Span* DoSampledAllocation(size_t size) {
-
-  // Grab the stack trace outside the heap lock
-  StackTrace tmp;
-  tmp.depth = GetStackTrace(tmp.stack, kMaxStackDepth, 1);
-  tmp.size = size;
-
-  SpinLockHolder h(&pageheap_lock);
-  // Allocate span
-  Span *span = pageheap->New(pages(size == 0 ? 1 : size));
-  if (span == NULL) {
-    return NULL;
-  }
-
-  // Allocate stack trace
-  StackTrace *stack = stacktrace_allocator.New();
-  if (stack == NULL) {
-    // Sampling failed because of lack of memory
-    return span;
-  }
-
-  *stack = tmp;
-  span->sample = 1;
-  span->objects = stack;
-  DLL_Prepend(&sampled_objects, span);
-
-  return span;
-}
-#endif
-
-static inline bool CheckCachedSizeClass(void *ptr) {
-  PageID p = reinterpret_cast<uintptr_t>(ptr) >> kPageShift;
-  size_t cached_value = pageheap->GetSizeClassIfCached(p);
-  return cached_value == 0 ||
-      cached_value == pageheap->GetDescriptor(p)->sizeclass;
-}
-
-static inline void* CheckedMallocResult(void *result)
-{
-  ASSERT(result == 0 || CheckCachedSizeClass(result));
-  return result;
-}
-
-static inline void* SpanToMallocResult(Span *span) {
-  ASSERT_SPAN_COMMITTED(span);
-  pageheap->CacheSizeClass(span->start, 0);
-  void* result = reinterpret_cast<void*>(span->start << kPageShift);
-  POISON_ALLOCATION(result, span->length << kPageShift);
-  return CheckedMallocResult(result);
-}
-
-#ifdef WTF_CHANGES
-template <bool crashOnFailure>
-#endif
-static ALWAYS_INLINE void* do_malloc(size_t size) {
-  void* ret = NULL;
-
-#ifdef WTF_CHANGES
-    ASSERT(!isForbidden());
-#endif
-
-  // The following call forces module initialization
-  TCMalloc_ThreadCache* heap = TCMalloc_ThreadCache::GetCache();
-#ifndef WTF_CHANGES
-  if ((FLAGS_tcmalloc_sample_parameter > 0) && heap->SampleAllocation(size)) {
-    Span* span = DoSampledAllocation(size);
-    if (span != NULL) {
-      ret = SpanToMallocResult(span);
-    }
-  } else
-#endif
-  if (size > kMaxSize) {
-    // Use page-level allocator
-    SpinLockHolder h(&pageheap_lock);
-    Span* span = pageheap->New(pages(size));
-    if (span != NULL) {
-      ret = SpanToMallocResult(span);
-    }
-  } else {
-    // The common case, and also the simplest.  This just pops the
-    // size-appropriate freelist, afer replenishing it if it's empty.
-    ret = CheckedMallocResult(heap->Allocate(size));
-  }
-  if (!ret) {
-#ifdef WTF_CHANGES
-    if (crashOnFailure) // This branch should be optimized out by the compiler.
-        CRASH();
-#else
-    errno = ENOMEM;
-#endif
-  }
-  return ret;
-}
-
-static ALWAYS_INLINE void do_free(void* ptr) {
-  if (ptr == NULL) return;
-  ASSERT(pageheap != NULL);  // Should not call free() before malloc()
-  const PageID p = reinterpret_cast<uintptr_t>(ptr) >> kPageShift;
-  Span* span = NULL;
-  size_t cl = pageheap->GetSizeClassIfCached(p);
-
-  if (cl == 0) {
-    span = pageheap->GetDescriptor(p);
-    RELEASE_ASSERT(span->isValid());
-    cl = span->sizeclass;
-    pageheap->CacheSizeClass(p, cl);
-  }
-  if (cl != 0) {
-#ifndef NO_TCMALLOC_SAMPLES
-    ASSERT(!pageheap->GetDescriptor(p)->sample);
-#endif
-    TCMalloc_ThreadCache* heap = TCMalloc_ThreadCache::GetCacheIfPresent();
-    if (heap != NULL) {
-      heap->Deallocate(HardenedSLL::create(ptr), cl);
-    } else {
-      // Delete directly into central cache
-      POISON_DEALLOCATION(ptr, ByteSizeForClass(cl));
-      SLL_SetNext(HardenedSLL::create(ptr), HardenedSLL::null(), central_cache[cl].entropy());
-      central_cache[cl].InsertRange(HardenedSLL::create(ptr), HardenedSLL::create(ptr), 1);
-    }
-  } else {
-    SpinLockHolder h(&pageheap_lock);
-    ASSERT(reinterpret_cast<uintptr_t>(ptr) % kPageSize == 0);
-    ASSERT(span != NULL && span->start == p);
-#ifndef NO_TCMALLOC_SAMPLES
-    if (span->sample) {
-      DLL_Remove(span);
-      stacktrace_allocator.Delete(reinterpret_cast<StackTrace*>(span->objects));
-      span->objects = NULL;
-    }
-#endif
-
-    POISON_DEALLOCATION(ptr, span->length << kPageShift);
-    pageheap->Delete(span);
-  }
-}
-
-#ifndef WTF_CHANGES
-// For use by exported routines below that want specific alignments
-//
-// Note: this code can be slow, and can significantly fragment memory.
-// The expectation is that memalign/posix_memalign/valloc/pvalloc will
-// not be invoked very often.  This requirement simplifies our
-// implementation and allows us to tune for expected allocation
-// patterns.
-static void* do_memalign(size_t align, size_t size) {
-  ASSERT((align & (align - 1)) == 0);
-  ASSERT(align > 0);
-  if (pageheap == NULL) TCMalloc_ThreadCache::InitModule();
-
-  // Allocate at least one byte to avoid boundary conditions below
-  if (size == 0) size = 1;
-
-  if (size <= kMaxSize && align < kPageSize) {
-    // Search through acceptable size classes looking for one with
-    // enough alignment.  This depends on the fact that
-    // InitSizeClasses() currently produces several size classes that
-    // are aligned at powers of two.  We will waste time and space if
-    // we miss in the size class array, but that is deemed acceptable
-    // since memalign() should be used rarely.
-    size_t cl = SizeClass(size);
-    while (cl < kNumClasses && ((class_to_size[cl] & (align - 1)) != 0)) {
-      cl++;
-    }
-    if (cl < kNumClasses) {
-      TCMalloc_ThreadCache* heap = TCMalloc_ThreadCache::GetCache();
-      return CheckedMallocResult(heap->Allocate(class_to_size[cl]));
-    }
-  }
-
-  // We will allocate directly from the page heap
-  SpinLockHolder h(&pageheap_lock);
-
-  if (align <= kPageSize) {
-    // Any page-level allocation will be fine
-    // TODO: We could put the rest of this page in the appropriate
-    // TODO: cache but it does not seem worth it.
-    Span* span = pageheap->New(pages(size));
-    return span == NULL ? NULL : SpanToMallocResult(span);
-  }
-
-  // Allocate extra pages and carve off an aligned portion
-  const Length alloc = pages(size + align);
-  Span* span = pageheap->New(alloc);
-  if (span == NULL) return NULL;
-
-  // Skip starting portion so that we end up aligned
-  Length skip = 0;
-  while ((((span->start+skip) << kPageShift) & (align - 1)) != 0) {
-    skip++;
-  }
-  ASSERT(skip < alloc);
-  if (skip > 0) {
-    Span* rest = pageheap->Split(span, skip);
-    pageheap->Delete(span);
-    span = rest;
-  }
-
-  // Skip trailing portion that we do not need to return
-  const Length needed = pages(size);
-  ASSERT(span->length >= needed);
-  if (span->length > needed) {
-    Span* trailer = pageheap->Split(span, needed);
-    pageheap->Delete(trailer);
-  }
-  return SpanToMallocResult(span);
-}
-#endif
-
-// Helpers for use by exported routines below:
-
-#ifndef WTF_CHANGES
-static inline void do_malloc_stats() {
-  PrintStats(1);
-}
-#endif
-
-static inline int do_mallopt(int, int) {
-  return 1;     // Indicates error
-}
-
-#ifdef HAVE_STRUCT_MALLINFO  // mallinfo isn't defined on freebsd, for instance
-static inline struct mallinfo do_mallinfo() {
-  TCMallocStats stats;
-  ExtractStats(&stats, NULL);
-
-  // Just some of the fields are filled in.
-  struct mallinfo info;
-  memset(&info, 0, sizeof(info));
-
-  // Unfortunately, the struct contains "int" field, so some of the
-  // size values will be truncated.
-  info.arena     = static_cast<int>(stats.system_bytes);
-  info.fsmblks   = static_cast<int>(stats.thread_bytes
-                                    + stats.central_bytes
-                                    + stats.transfer_bytes);
-  info.fordblks  = static_cast<int>(stats.pageheap_bytes);
-  info.uordblks  = static_cast<int>(stats.system_bytes
-                                    - stats.thread_bytes
-                                    - stats.central_bytes
-                                    - stats.transfer_bytes
-                                    - stats.pageheap_bytes);
-
-  return info;
-}
-#endif
-
-//-------------------------------------------------------------------
-// Exported routines
-//-------------------------------------------------------------------
-
-// CAVEAT: The code structure below ensures that MallocHook methods are always
-//         called from the stack frame of the invoked allocation function.
-//         heap-checker.cc depends on this to start a stack trace from
-//         the call to the (de)allocation function.
-
-#ifndef WTF_CHANGES
-extern "C" 
-#else
-#define do_malloc do_malloc<crashOnFailure>
-
-template <bool crashOnFailure>
-ALWAYS_INLINE void* malloc(size_t);
-
-void* fastMalloc(size_t size)
-{
-    return malloc<true>(size);
-}
-
-TryMallocReturnValue tryFastMalloc(size_t size)
-{
-    return malloc<false>(size);
-}
-
-template <bool crashOnFailure>
-ALWAYS_INLINE
-#endif
-void* malloc(size_t size) {
-#if ENABLE(WTF_MALLOC_VALIDATION)
-    if (std::numeric_limits<size_t>::max() - Internal::ValidationBufferSize <= size)  // If overflow would occur...
-        return 0;
-    void* result = do_malloc(size + Internal::ValidationBufferSize);
-    if (!result)
-        return 0;
-
-    Internal::ValidationHeader* header = static_cast<Internal::ValidationHeader*>(result);
-    header->m_size = size;
-    header->m_type = Internal::AllocTypeMalloc;
-    header->m_prefix = static_cast<unsigned>(Internal::ValidationPrefix);
-    result = header + 1;
-    *Internal::fastMallocValidationSuffix(result) = Internal::ValidationSuffix;
-    fastMallocValidate(result);
-#else
-    void* result = do_malloc(size);
-#endif
-
-#ifndef WTF_CHANGES
-  MallocHook::InvokeNewHook(result, size);
-#endif
-  return result;
-}
-
-#ifndef WTF_CHANGES
-extern "C" 
-#endif
-void free(void* ptr) {
-#ifndef WTF_CHANGES
-  MallocHook::InvokeDeleteHook(ptr);
-#endif
-
-#if ENABLE(WTF_MALLOC_VALIDATION)
-    if (!ptr)
-        return;
-
-    fastMallocValidate(ptr);
-    Internal::ValidationHeader* header = Internal::fastMallocValidationHeader(ptr);
-    memset(ptr, 0xCC, header->m_size);
-    do_free(header);
-#else
-    do_free(ptr);
-#endif
-}
-
-#ifndef WTF_CHANGES
-extern "C" 
-#else
-template <bool crashOnFailure>
-ALWAYS_INLINE void* calloc(size_t, size_t);
-
-void* fastCalloc(size_t n, size_t elem_size)
-{
-    void* result = calloc<true>(n, elem_size);
-#if ENABLE(WTF_MALLOC_VALIDATION)
-    fastMallocValidate(result);
-#endif
-    return result;
-}
-
-TryMallocReturnValue tryFastCalloc(size_t n, size_t elem_size)
-{
-    void* result = calloc<false>(n, elem_size);
-#if ENABLE(WTF_MALLOC_VALIDATION)
-    fastMallocValidate(result);
-#endif
-    return result;
-}
-
-template <bool crashOnFailure>
-ALWAYS_INLINE
-#endif
-void* calloc(size_t n, size_t elem_size) {
-  size_t totalBytes = n * elem_size;
-    
-  // Protect against overflow
-  if (n > 1 && elem_size && (totalBytes / elem_size) != n)
-    return 0;
-
-#if ENABLE(WTF_MALLOC_VALIDATION)
-    void* result = malloc<crashOnFailure>(totalBytes);
-    if (!result)
-        return 0;
-
-    memset(result, 0, totalBytes);
-    fastMallocValidate(result);
-#else
-    void* result = do_malloc(totalBytes);
-    if (result != NULL) {
-        memset(result, 0, totalBytes);
-    }
-#endif
-
-#ifndef WTF_CHANGES
-  MallocHook::InvokeNewHook(result, totalBytes);
-#endif
-  return result;
-}
-
-// Since cfree isn't used anywhere, we don't compile it in.
-#ifndef WTF_CHANGES
-#ifndef WTF_CHANGES
-extern "C" 
-#endif
-void cfree(void* ptr) {
-#ifndef WTF_CHANGES
-    MallocHook::InvokeDeleteHook(ptr);
-#endif
-  do_free(ptr);
-}
-#endif
-
-#ifndef WTF_CHANGES
-extern "C" 
-#else
-template <bool crashOnFailure>
-ALWAYS_INLINE void* realloc(void*, size_t);
-
-void* fastRealloc(void* old_ptr, size_t new_size)
-{
-#if ENABLE(WTF_MALLOC_VALIDATION)
-    fastMallocValidate(old_ptr);
-#endif
-    void* result = realloc<true>(old_ptr, new_size);
-#if ENABLE(WTF_MALLOC_VALIDATION)
-    fastMallocValidate(result);
-#endif
-    return result;
-}
-
-TryMallocReturnValue tryFastRealloc(void* old_ptr, size_t new_size)
-{
-#if ENABLE(WTF_MALLOC_VALIDATION)
-    fastMallocValidate(old_ptr);
-#endif
-    void* result = realloc<false>(old_ptr, new_size);
-#if ENABLE(WTF_MALLOC_VALIDATION)
-    fastMallocValidate(result);
-#endif
-    return result;
-}
-
-template <bool crashOnFailure>
-ALWAYS_INLINE
-#endif
-void* realloc(void* old_ptr, size_t new_size) {
-  if (old_ptr == NULL) {
-#if ENABLE(WTF_MALLOC_VALIDATION)
-    void* result = malloc<crashOnFailure>(new_size);
-#else
-    void* result = do_malloc(new_size);
-#ifndef WTF_CHANGES
-    MallocHook::InvokeNewHook(result, new_size);
-#endif
-#endif
-    return result;
-  }
-  if (new_size == 0) {
-#ifndef WTF_CHANGES
-    MallocHook::InvokeDeleteHook(old_ptr);
-#endif
-    free(old_ptr);
-    return NULL;
-  }
-
-#if ENABLE(WTF_MALLOC_VALIDATION)
-    if (std::numeric_limits<size_t>::max() - Internal::ValidationBufferSize <= new_size)  // If overflow would occur...
-        return 0;
-    Internal::ValidationHeader* header = Internal::fastMallocValidationHeader(old_ptr);
-    fastMallocValidate(old_ptr);
-    old_ptr = header;
-    header->m_size = new_size;
-    new_size += Internal::ValidationBufferSize;
-#endif
-
-  // Get the size of the old entry
-  const PageID p = reinterpret_cast<uintptr_t>(old_ptr) >> kPageShift;
-  size_t cl = pageheap->GetSizeClassIfCached(p);
-  Span *span = NULL;
-  size_t old_size;
-  if (cl == 0) {
-    span = pageheap->GetDescriptor(p);
-    cl = span->sizeclass;
-    pageheap->CacheSizeClass(p, cl);
-  }
-  if (cl != 0) {
-    old_size = ByteSizeForClass(cl);
-  } else {
-    ASSERT(span != NULL);
-    old_size = span->length << kPageShift;
-  }
-
-  // Reallocate if the new size is larger than the old size,
-  // or if the new size is significantly smaller than the old size.
-  if ((new_size > old_size) || (AllocationSize(new_size) < old_size)) {
-    // Need to reallocate
-    void* new_ptr = do_malloc(new_size);
-    if (new_ptr == NULL) {
-      return NULL;
-    }
-#ifndef WTF_CHANGES
-    MallocHook::InvokeNewHook(new_ptr, new_size);
-#endif
-    memcpy(new_ptr, old_ptr, ((old_size < new_size) ? old_size : new_size));
-#ifndef WTF_CHANGES
-    MallocHook::InvokeDeleteHook(old_ptr);
-#endif
-    // We could use a variant of do_free() that leverages the fact
-    // that we already know the sizeclass of old_ptr.  The benefit
-    // would be small, so don't bother.
-    do_free(old_ptr);
-#if ENABLE(WTF_MALLOC_VALIDATION)
-    new_ptr = static_cast<Internal::ValidationHeader*>(new_ptr) + 1;
-    *Internal::fastMallocValidationSuffix(new_ptr) = Internal::ValidationSuffix;
-#endif
-    return new_ptr;
-  } else {
-#if ENABLE(WTF_MALLOC_VALIDATION)
-    old_ptr = static_cast<Internal::ValidationHeader*>(old_ptr) + 1; // Set old_ptr back to the user pointer.
-    *Internal::fastMallocValidationSuffix(old_ptr) = Internal::ValidationSuffix;
-#endif
-    return old_ptr;
-  }
-}
-
-#ifdef WTF_CHANGES
-#undef do_malloc
-#else
-
-static SpinLock set_new_handler_lock = SPINLOCK_INITIALIZER;
-
-static inline void* cpp_alloc(size_t size, bool nothrow) {
-  for (;;) {
-    void* p = do_malloc(size);
-#ifdef PREANSINEW
-    return p;
-#else
-    if (p == NULL) {  // allocation failed
-      // Get the current new handler.  NB: this function is not
-      // thread-safe.  We make a feeble stab at making it so here, but
-      // this lock only protects against tcmalloc interfering with
-      // itself, not with other libraries calling set_new_handler.
-      std::new_handler nh;
-      {
-        SpinLockHolder h(&set_new_handler_lock);
-        nh = std::set_new_handler(0);
-        (void) std::set_new_handler(nh);
-      }
-      // If no new_handler is established, the allocation failed.
-      if (!nh) {
-        if (nothrow) return 0;
-        throw std::bad_alloc();
-      }
-      // Otherwise, try the new_handler.  If it returns, retry the
-      // allocation.  If it throws std::bad_alloc, fail the allocation.
-      // if it throws something else, don't interfere.
-      try {
-        (*nh)();
-      } catch (const std::bad_alloc&) {
-        if (!nothrow) throw;
-        return p;
-      }
-    } else {  // allocation success
-      return p;
-    }
-#endif
-  }
-}
-
-extern "C" void* memalign(size_t align, size_t size) __THROW {
-  void* result = do_memalign(align, size);
-  MallocHook::InvokeNewHook(result, size);
-  return result;
-}
-
-extern "C" int posix_memalign(void** result_ptr, size_t align, size_t size)
-    __THROW {
-  if (((align % sizeof(void*)) != 0) ||
-      ((align & (align - 1)) != 0) ||
-      (align == 0)) {
-    return EINVAL;
-  }
-
-  void* result = do_memalign(align, size);
-  MallocHook::InvokeNewHook(result, size);
-  if (result == NULL) {
-    return ENOMEM;
-  } else {
-    *result_ptr = result;
-    return 0;
-  }
-}
-
-static size_t pagesize = 0;
-
-extern "C" void* valloc(size_t size) __THROW {
-  // Allocate page-aligned object of length >= size bytes
-  if (pagesize == 0) pagesize = getpagesize();
-  void* result = do_memalign(pagesize, size);
-  MallocHook::InvokeNewHook(result, size);
-  return result;
-}
-
-extern "C" void* pvalloc(size_t size) __THROW {
-  // Round up size to a multiple of pagesize
-  if (pagesize == 0) pagesize = getpagesize();
-  size = (size + pagesize - 1) & ~(pagesize - 1);
-  void* result = do_memalign(pagesize, size);
-  MallocHook::InvokeNewHook(result, size);
-  return result;
-}
-
-extern "C" void malloc_stats(void) {
-  do_malloc_stats();
-}
-
-extern "C" int mallopt(int cmd, int value) {
-  return do_mallopt(cmd, value);
-}
-
-#ifdef HAVE_STRUCT_MALLINFO
-extern "C" struct mallinfo mallinfo(void) {
-  return do_mallinfo();
-}
-#endif
-
-//-------------------------------------------------------------------
-// Some library routines on RedHat 9 allocate memory using malloc()
-// and free it using __libc_free() (or vice-versa).  Since we provide
-// our own implementations of malloc/free, we need to make sure that
-// the __libc_XXX variants (defined as part of glibc) also point to
-// the same implementations.
-//-------------------------------------------------------------------
-
-#if defined(__GLIBC__)
-extern "C" {
-#if COMPILER(GCC) && !defined(__MACH__) && defined(HAVE___ATTRIBUTE__)
-  // Potentially faster variants that use the gcc alias extension.
-  // Mach-O (Darwin) does not support weak aliases, hence the __MACH__ check.
-# define ALIAS(x) __attribute__ ((weak, alias (x)))
-  void* __libc_malloc(size_t size)              ALIAS("malloc");
-  void  __libc_free(void* ptr)                  ALIAS("free");
-  void* __libc_realloc(void* ptr, size_t size)  ALIAS("realloc");
-  void* __libc_calloc(size_t n, size_t size)    ALIAS("calloc");
-  void  __libc_cfree(void* ptr)                 ALIAS("cfree");
-  void* __libc_memalign(size_t align, size_t s) ALIAS("memalign");
-  void* __libc_valloc(size_t size)              ALIAS("valloc");
-  void* __libc_pvalloc(size_t size)             ALIAS("pvalloc");
-  int __posix_memalign(void** r, size_t a, size_t s) ALIAS("posix_memalign");
-# undef ALIAS
-# else   /* not __GNUC__ */
-  // Portable wrappers
-  void* __libc_malloc(size_t size)              { return malloc(size);       }
-  void  __libc_free(void* ptr)                  { free(ptr);                 }
-  void* __libc_realloc(void* ptr, size_t size)  { return realloc(ptr, size); }
-  void* __libc_calloc(size_t n, size_t size)    { return calloc(n, size);    }
-  void  __libc_cfree(void* ptr)                 { cfree(ptr);                }
-  void* __libc_memalign(size_t align, size_t s) { return memalign(align, s); }
-  void* __libc_valloc(size_t size)              { return valloc(size);       }
-  void* __libc_pvalloc(size_t size)             { return pvalloc(size);      }
-  int __posix_memalign(void** r, size_t a, size_t s) {
-    return posix_memalign(r, a, s);
-  }
-# endif  /* __GNUC__ */
-}
-#endif   /* __GLIBC__ */
-
-// Override __libc_memalign in libc on linux boxes specially.
-// They have a bug in libc that causes them to (very rarely) allocate
-// with __libc_memalign() yet deallocate with free() and the
-// definitions above don't catch it.
-// This function is an exception to the rule of calling MallocHook method
-// from the stack frame of the allocation function;
-// heap-checker handles this special case explicitly.
-static void *MemalignOverride(size_t align, size_t size, const void *caller)
-    __THROW {
-  void* result = do_memalign(align, size);
-  MallocHook::InvokeNewHook(result, size);
-  return result;
-}
-void *(*__memalign_hook)(size_t, size_t, const void *) = MemalignOverride;
-
-#endif
-
-#ifdef WTF_CHANGES
-void releaseFastMallocFreeMemory()
-{
-    // Flush free pages in the current thread cache back to the page heap.
-    if (TCMalloc_ThreadCache* threadCache = TCMalloc_ThreadCache::GetCacheIfPresent())
-        threadCache->Cleanup();
-
-    SpinLockHolder h(&pageheap_lock);
-    pageheap->ReleaseFreePages();
-}
-
-FastMallocStatistics fastMallocStatistics()
-{
-    FastMallocStatistics statistics;
-
-    SpinLockHolder lockHolder(&pageheap_lock);
-    statistics.reservedVMBytes = static_cast<size_t>(pageheap->SystemBytes());
-    statistics.committedVMBytes = statistics.reservedVMBytes - pageheap->ReturnedBytes();
-
-    statistics.freeListBytes = 0;
-    for (unsigned cl = 0; cl < kNumClasses; ++cl) {
-        const int length = central_cache[cl].length();
-        const int tc_length = central_cache[cl].tc_length();
-
-        statistics.freeListBytes += ByteSizeForClass(cl) * (length + tc_length);
-    }
-    for (TCMalloc_ThreadCache* threadCache = thread_heaps; threadCache ; threadCache = threadCache->next_)
-        statistics.freeListBytes += threadCache->Size();
-
-    return statistics;
-}
-
-size_t fastMallocSize(const void* ptr)
-{
-#if ENABLE(WTF_MALLOC_VALIDATION)
-    return Internal::fastMallocValidationHeader(const_cast<void*>(ptr))->m_size;
-#else
-    const PageID p = reinterpret_cast<uintptr_t>(ptr) >> kPageShift;
-    Span* span = pageheap->GetDescriptorEnsureSafe(p);
-
-    if (!span || span->free)
-        return 0;
-
-    for (HardenedSLL free = span->objects; free; free = SLL_Next(free, HARDENING_ENTROPY)) {
-        if (ptr == free.value())
-            return 0;
-    }
-
-    if (size_t cl = span->sizeclass)
-        return ByteSizeForClass(cl);
-
-    return span->length << kPageShift;
-#endif
-}
-
-#if OS(DARWIN)
-
-template <typename T>
-T* RemoteMemoryReader::nextEntryInHardenedLinkedList(T** remoteAddress, uintptr_t entropy) const
-{
-    T** localAddress = (*this)(remoteAddress);
-    if (!localAddress)
-        return 0;
-    T* hardenedNext = *localAddress;
-    if (!hardenedNext || hardenedNext == (void*)entropy)
-        return 0;
-    return XOR_MASK_PTR_WITH_KEY(hardenedNext, remoteAddress, entropy);
-}
-
-class FreeObjectFinder {
-    const RemoteMemoryReader& m_reader;
-    HashSet<void*> m_freeObjects;
-
-public:
-    FreeObjectFinder(const RemoteMemoryReader& reader) : m_reader(reader) { }
-
-    void visit(void* ptr) { m_freeObjects.add(ptr); }
-    bool isFreeObject(void* ptr) const { return m_freeObjects.contains(ptr); }
-    bool isFreeObject(vm_address_t ptr) const { return isFreeObject(reinterpret_cast<void*>(ptr)); }
-    size_t freeObjectCount() const { return m_freeObjects.size(); }
-
-    void findFreeObjects(TCMalloc_ThreadCache* threadCache)
-    {
-        for (; threadCache; threadCache = (threadCache->next_ ? m_reader(threadCache->next_) : 0))
-            threadCache->enumerateFreeObjects(*this, m_reader);
-    }
-
-    void findFreeObjects(TCMalloc_Central_FreeListPadded* centralFreeList, size_t numSizes, TCMalloc_Central_FreeListPadded* remoteCentralFreeList)
-    {
-        for (unsigned i = 0; i < numSizes; i++)
-            centralFreeList[i].enumerateFreeObjects(*this, m_reader, remoteCentralFreeList + i);
-    }
-};
-
-class PageMapFreeObjectFinder {
-    const RemoteMemoryReader& m_reader;
-    FreeObjectFinder& m_freeObjectFinder;
-    uintptr_t m_entropy;
-
-public:
-    PageMapFreeObjectFinder(const RemoteMemoryReader& reader, FreeObjectFinder& freeObjectFinder, uintptr_t entropy)
-        : m_reader(reader)
-        , m_freeObjectFinder(freeObjectFinder)
-        , m_entropy(entropy)
-    {
-#if ENABLE(TCMALLOC_HARDENING)
-        ASSERT(m_entropy);
-#endif
-    }
-
-    int visit(void* ptr) const
-    {
-        if (!ptr)
-            return 1;
-
-        Span* span = m_reader(reinterpret_cast<Span*>(ptr));
-        if (!span)
-            return 1;
-
-        if (span->free) {
-            void* ptr = reinterpret_cast<void*>(span->start << kPageShift);
-            m_freeObjectFinder.visit(ptr);
-        } else if (span->sizeclass) {
-            // Walk the free list of the small-object span, keeping track of each object seen
-            for (HardenedSLL nextObject = span->objects; nextObject; nextObject.setValue(m_reader.nextEntryInHardenedLinkedList(reinterpret_cast<void**>(nextObject.value()), m_entropy)))
-                m_freeObjectFinder.visit(nextObject.value());
-        }
-        return span->length;
-    }
-};
-
-class PageMapMemoryUsageRecorder {
-    task_t m_task;
-    void* m_context;
-    unsigned m_typeMask;
-    vm_range_recorder_t* m_recorder;
-    const RemoteMemoryReader& m_reader;
-    const FreeObjectFinder& m_freeObjectFinder;
-
-    HashSet<void*> m_seenPointers;
-    Vector<Span*> m_coalescedSpans;
-
-public:
-    PageMapMemoryUsageRecorder(task_t task, void* context, unsigned typeMask, vm_range_recorder_t* recorder, const RemoteMemoryReader& reader, const FreeObjectFinder& freeObjectFinder)
-        : m_task(task)
-        , m_context(context)
-        , m_typeMask(typeMask)
-        , m_recorder(recorder)
-        , m_reader(reader)
-        , m_freeObjectFinder(freeObjectFinder)
-    { }
-
-    ~PageMapMemoryUsageRecorder()
-    {
-        ASSERT(!m_coalescedSpans.size());
-    }
-
-    void recordPendingRegions()
-    {
-        if (!(m_typeMask & (MALLOC_PTR_IN_USE_RANGE_TYPE | MALLOC_PTR_REGION_RANGE_TYPE))) {
-            m_coalescedSpans.clear();
-            return;
-        }
-
-        Vector<vm_range_t, 1024> allocatedPointers;
-        for (size_t i = 0; i < m_coalescedSpans.size(); ++i) {
-            Span *theSpan = m_coalescedSpans[i];
-            if (theSpan->free)
-                continue;
-
-            vm_address_t spanStartAddress = theSpan->start << kPageShift;
-            vm_size_t spanSizeInBytes = theSpan->length * kPageSize;
-
-            if (!theSpan->sizeclass) {
-                // If it's an allocated large object span, mark it as in use
-                if (!m_freeObjectFinder.isFreeObject(spanStartAddress))
-                    allocatedPointers.append((vm_range_t){spanStartAddress, spanSizeInBytes});
-            } else {
-                const size_t objectSize = ByteSizeForClass(theSpan->sizeclass);
-
-                // Mark each allocated small object within the span as in use
-                const vm_address_t endOfSpan = spanStartAddress + spanSizeInBytes;
-                for (vm_address_t object = spanStartAddress; object + objectSize <= endOfSpan; object += objectSize) {
-                    if (!m_freeObjectFinder.isFreeObject(object))
-                        allocatedPointers.append((vm_range_t){object, objectSize});
-                }
-            }
-        }
-
-        (*m_recorder)(m_task, m_context, m_typeMask & (MALLOC_PTR_IN_USE_RANGE_TYPE | MALLOC_PTR_REGION_RANGE_TYPE), allocatedPointers.data(), allocatedPointers.size());
-
-        m_coalescedSpans.clear();
-    }
-
-    int visit(void* ptr)
-    {
-        if (!ptr)
-            return 1;
-
-        Span* span = m_reader(reinterpret_cast<Span*>(ptr));
-        if (!span || !span->start)
-            return 1;
-
-        if (m_seenPointers.contains(ptr))
-            return span->length;
-        m_seenPointers.add(ptr);
-
-        if (!m_coalescedSpans.size()) {
-            m_coalescedSpans.append(span);
-            return span->length;
-        }
-
-        Span* previousSpan = m_coalescedSpans[m_coalescedSpans.size() - 1];
-        vm_address_t previousSpanStartAddress = previousSpan->start << kPageShift;
-        vm_size_t previousSpanSizeInBytes = previousSpan->length * kPageSize;
-
-        // If the new span is adjacent to the previous span, do nothing for now.
-        vm_address_t spanStartAddress = span->start << kPageShift;
-        if (spanStartAddress == previousSpanStartAddress + previousSpanSizeInBytes) {
-            m_coalescedSpans.append(span);
-            return span->length;
-        }
-
-        // New span is not adjacent to previous span, so record the spans coalesced so far.
-        recordPendingRegions();
-        m_coalescedSpans.append(span);
-
-        return span->length;
-    }
-};
-
-class AdminRegionRecorder {
-    task_t m_task;
-    void* m_context;
-    unsigned m_typeMask;
-    vm_range_recorder_t* m_recorder;
-
-    Vector<vm_range_t, 1024> m_pendingRegions;
-
-public:
-    AdminRegionRecorder(task_t task, void* context, unsigned typeMask, vm_range_recorder_t* recorder)
-        : m_task(task)
-        , m_context(context)
-        , m_typeMask(typeMask)
-        , m_recorder(recorder)
-    { }
-
-    void recordRegion(vm_address_t ptr, size_t size)
-    {
-        if (m_typeMask & MALLOC_ADMIN_REGION_RANGE_TYPE)
-            m_pendingRegions.append((vm_range_t){ ptr, size });
-    }
-
-    void visit(void *ptr, size_t size)
-    {
-        recordRegion(reinterpret_cast<vm_address_t>(ptr), size);
-    }
-
-    void recordPendingRegions()
-    {
-        if (m_pendingRegions.size()) {
-            (*m_recorder)(m_task, m_context, MALLOC_ADMIN_REGION_RANGE_TYPE, m_pendingRegions.data(), m_pendingRegions.size());
-            m_pendingRegions.clear();
-        }
-    }
-
-    ~AdminRegionRecorder()
-    {
-        ASSERT(!m_pendingRegions.size());
-    }
-};
-
-kern_return_t FastMallocZone::enumerate(task_t task, void* context, unsigned typeMask, vm_address_t zoneAddress, memory_reader_t reader, vm_range_recorder_t recorder)
-{
-    RemoteMemoryReader memoryReader(task, reader);
-
-    InitSizeClasses();
-
-    FastMallocZone* mzone = memoryReader(reinterpret_cast<FastMallocZone*>(zoneAddress));
-    TCMalloc_PageHeap* pageHeap = memoryReader(mzone->m_pageHeap);
-    TCMalloc_ThreadCache** threadHeapsPointer = memoryReader(mzone->m_threadHeaps);
-    TCMalloc_ThreadCache* threadHeaps = memoryReader(*threadHeapsPointer);
-
-    TCMalloc_Central_FreeListPadded* centralCaches = memoryReader(mzone->m_centralCaches, sizeof(TCMalloc_Central_FreeListPadded) * kNumClasses);
-
-    FreeObjectFinder finder(memoryReader);
-    finder.findFreeObjects(threadHeaps);
-    finder.findFreeObjects(centralCaches, kNumClasses, mzone->m_centralCaches);
-
-    TCMalloc_PageHeap::PageMap* pageMap = &pageHeap->pagemap_;
-    PageMapFreeObjectFinder pageMapFinder(memoryReader, finder, pageHeap->entropy_);
-    pageMap->visitValues(pageMapFinder, memoryReader);
-
-    PageMapMemoryUsageRecorder usageRecorder(task, context, typeMask, recorder, memoryReader, finder);
-    pageMap->visitValues(usageRecorder, memoryReader);
-    usageRecorder.recordPendingRegions();
-
-    AdminRegionRecorder adminRegionRecorder(task, context, typeMask, recorder);
-    pageMap->visitAllocations(adminRegionRecorder, memoryReader);
-
-    PageHeapAllocator<Span>* spanAllocator = memoryReader(mzone->m_spanAllocator);
-    PageHeapAllocator<TCMalloc_ThreadCache>* pageHeapAllocator = memoryReader(mzone->m_pageHeapAllocator);
-
-    spanAllocator->recordAdministrativeRegions(adminRegionRecorder, memoryReader);
-    pageHeapAllocator->recordAdministrativeRegions(adminRegionRecorder, memoryReader);
-
-    adminRegionRecorder.recordPendingRegions();
-
-    return 0;
-}
-
-size_t FastMallocZone::size(malloc_zone_t*, const void*)
-{
-    return 0;
-}
-
-void* FastMallocZone::zoneMalloc(malloc_zone_t*, size_t)
-{
-    return 0;
-}
-
-void* FastMallocZone::zoneCalloc(malloc_zone_t*, size_t, size_t)
-{
-    return 0;
-}
-
-void FastMallocZone::zoneFree(malloc_zone_t*, void* ptr)
-{
-    // Due to <rdar://problem/5671357> zoneFree may be called by the system free even if the pointer
-    // is not in this zone.  When this happens, the pointer being freed was not allocated by any
-    // zone so we need to print a useful error for the application developer.
-    malloc_printf("*** error for object %p: pointer being freed was not allocated\n", ptr);
-}
-
-void* FastMallocZone::zoneRealloc(malloc_zone_t*, void*, size_t)
-{
-    return 0;
-}
-
-
-#undef malloc
-#undef free
-#undef realloc
-#undef calloc
-
-extern "C" {
-malloc_introspection_t jscore_fastmalloc_introspection = { &FastMallocZone::enumerate, &FastMallocZone::goodSize, &FastMallocZone::check, &FastMallocZone::print,
-    &FastMallocZone::log, &FastMallocZone::forceLock, &FastMallocZone::forceUnlock, &FastMallocZone::statistics
-
-#if OS(IOS) || __MAC_OS_X_VERSION_MAX_ALLOWED >= 1060
-    , 0 // zone_locked will not be called on the zone unless it advertises itself as version five or higher.
-#endif
-#if OS(IOS) || __MAC_OS_X_VERSION_MAX_ALLOWED >= 1070
-    , 0, 0, 0, 0 // These members will not be used unless the zone advertises itself as version seven or higher.
-#endif
-
-    };
-}
-
-FastMallocZone::FastMallocZone(TCMalloc_PageHeap* pageHeap, TCMalloc_ThreadCache** threadHeaps, TCMalloc_Central_FreeListPadded* centralCaches, PageHeapAllocator<Span>* spanAllocator, PageHeapAllocator<TCMalloc_ThreadCache>* pageHeapAllocator)
-    : m_pageHeap(pageHeap)
-    , m_threadHeaps(threadHeaps)
-    , m_centralCaches(centralCaches)
-    , m_spanAllocator(spanAllocator)
-    , m_pageHeapAllocator(pageHeapAllocator)
-{
-    memset(&m_zone, 0, sizeof(m_zone));
-    m_zone.version = 4;
-    m_zone.zone_name = "JavaScriptCore FastMalloc";
-    m_zone.size = &FastMallocZone::size;
-    m_zone.malloc = &FastMallocZone::zoneMalloc;
-    m_zone.calloc = &FastMallocZone::zoneCalloc;
-    m_zone.realloc = &FastMallocZone::zoneRealloc;
-    m_zone.free = &FastMallocZone::zoneFree;
-    m_zone.valloc = &FastMallocZone::zoneValloc;
-    m_zone.destroy = &FastMallocZone::zoneDestroy;
-    m_zone.introspect = &jscore_fastmalloc_introspection;
-    malloc_zone_register(&m_zone);
-}
-
-
-void FastMallocZone::init()
-{
-    static FastMallocZone zone(pageheap, &thread_heaps, static_cast<TCMalloc_Central_FreeListPadded*>(central_cache), &span_allocator, &threadheap_allocator);
-}
-
-#endif // OS(DARWIN)
-
-} // namespace WTF
-#endif // WTF_CHANGES
-
-#endif // FORCE_SYSTEM_MALLOC