Move Partition Allocator into Chromium base.

third_party/WebKit/Source/wtf/allocator/PartitionAlloc.h

Index: third_party/WebKit/Source/wtf/allocator/PartitionAlloc.h
diff --git a/third_party/WebKit/Source/wtf/allocator/PartitionAlloc.h b/third_party/WebKit/Source/wtf/allocator/PartitionAlloc.h
deleted file mode 100644
index aa3c0bbc527ebd92a65eecf29dd0b9a32db54f69..0000000000000000000000000000000000000000
--- a/third_party/WebKit/Source/wtf/allocator/PartitionAlloc.h
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-/*
- * Copyright (C) 2013 Google 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.
- */
-
-#ifndef WTF_PartitionAlloc_h
-#define WTF_PartitionAlloc_h
-
-// DESCRIPTION
-// partitionAlloc() / partitionAllocGeneric() and partitionFree() /
-// partitionFreeGeneric() are approximately analagous to malloc() and free().
-//
-// The main difference is that a PartitionRoot / PartitionRootGeneric object
-// must be supplied to these functions, representing a specific "heap partition"
-// that will be used to satisfy the allocation. Different partitions are
-// guaranteed to exist in separate address spaces, including being separate from
-// the main system heap. If the contained objects are all freed, physical memory
-// is returned to the system but the address space remains reserved.
-// See PartitionAlloc.md for other security properties PartitionAlloc provides.
-//
-// THE ONLY LEGITIMATE WAY TO OBTAIN A PartitionRoot IS THROUGH THE
-// SizeSpecificPartitionAllocator / PartitionAllocatorGeneric classes. To
-// minimize the instruction count to the fullest extent possible, the
-// PartitionRoot is really just a header adjacent to other data areas provided
-// by the allocator class.
-//
-// The partitionAlloc() variant of the API has the following caveats:
-// - Allocations and frees against a single partition must be single threaded.
-// - Allocations must not exceed a max size, chosen at compile-time via a
-// templated parameter to PartitionAllocator.
-// - Allocation sizes must be aligned to the system pointer size.
-// - Allocations are bucketed exactly according to size.
-//
-// And for partitionAllocGeneric():
-// - Multi-threaded use against a single partition is ok; locking is handled.
-// - Allocations of any arbitrary size can be handled (subject to a limit of
-// INT_MAX bytes for security reasons).
-// - Bucketing is by approximate size, for example an allocation of 4000 bytes
-// might be placed into a 4096-byte bucket. Bucket sizes are chosen to try and
-// keep worst-case waste to ~10%.
-//
-// The allocators are designed to be extremely fast, thanks to the following
-// properties and design:
-// - Just two single (reasonably predicatable) branches in the hot / fast path
-//   for both allocating and (significantly) freeing.
-// - A minimal number of operations in the hot / fast path, with the slow paths
-//   in separate functions, leading to the possibility of inlining.
-// - Each partition page (which is usually multiple physical pages) has a
-//   metadata structure which allows fast mapping of free() address to an
-//   underlying bucket.
-// - Supports a lock-free API for fast performance in single-threaded cases.
-// - The freelist for a given bucket is split across a number of partition
-//   pages, enabling various simple tricks to try and minimize fragmentation.
-// - Fine-grained bucket sizes leading to less waste and better packing.
-//
-// The following security properties could be investigated in the future:
-// - Per-object bucketing (instead of per-size) is mostly available at the API,
-// but not used yet.
-// - No randomness of freelist entries or bucket position.
-// - Better checking for wild pointers in free().
-// - Better freelist masking function to guarantee fault on 32-bit.
-
-#include "wtf/Assertions.h"
-#include "wtf/BitwiseOperations.h"
-#include "wtf/ByteSwap.h"
-#include "wtf/CPU.h"
-#include "wtf/SpinLock.h"
-#include "wtf/TypeTraits.h"
-#include "wtf/allocator/PageAllocator.h"
-
-#include <limits.h>
-
-#if defined(MEMORY_TOOL_REPLACES_ALLOCATOR)
-#include <stdlib.h>
-#endif
-
-#if ENABLE(ASSERT)
-#include <string.h>
-#endif
-
-namespace WTF {
-
-// Allocation granularity of sizeof(void*) bytes.
-static const size_t kAllocationGranularity = sizeof(void*);
-static const size_t kAllocationGranularityMask = kAllocationGranularity - 1;
-static const size_t kBucketShift = (kAllocationGranularity == 8) ? 3 : 2;
-
-// Underlying partition storage pages are a power-of-two size. It is typical
-// for a partition page to be based on multiple system pages. Most references to
-// "page" refer to partition pages.
-// We also have the concept of "super pages" -- these are the underlying system
-// allocations we make. Super pages contain multiple partition pages inside them
-// and include space for a small amount of metadata per partition page.
-// Inside super pages, we store "slot spans". A slot span is a continguous range
-// of one or more partition pages that stores allocations of the same size.
-// Slot span sizes are adjusted depending on the allocation size, to make sure
-// the packing does not lead to unused (wasted) space at the end of the last
-// system page of the span. For our current max slot span size of 64k and other
-// constant values, we pack _all_ partitionAllocGeneric() sizes perfectly up
-// against the end of a system page.
-static const size_t kPartitionPageShift = 14;  // 16KB
-static const size_t kPartitionPageSize = 1 << kPartitionPageShift;
-static const size_t kPartitionPageOffsetMask = kPartitionPageSize - 1;
-static const size_t kPartitionPageBaseMask = ~kPartitionPageOffsetMask;
-static const size_t kMaxPartitionPagesPerSlotSpan = 4;
-
-// To avoid fragmentation via never-used freelist entries, we hand out partition
-// freelist sections gradually, in units of the dominant system page size.
-// What we're actually doing is avoiding filling the full partition page (16 KB)
-// with freelist pointers right away. Writing freelist pointers will fault and
-// dirty a private page, which is very wasteful if we never actually store
-// objects there.
-static const size_t kNumSystemPagesPerPartitionPage =
-    kPartitionPageSize / kSystemPageSize;
-static const size_t kMaxSystemPagesPerSlotSpan =
-    kNumSystemPagesPerPartitionPage * kMaxPartitionPagesPerSlotSpan;
-
-// We reserve virtual address space in 2MB chunks (aligned to 2MB as well).
-// These chunks are called "super pages". We do this so that we can store
-// metadata in the first few pages of each 2MB aligned section. This leads to
-// a very fast free(). We specifically choose 2MB because this virtual address
-// block represents a full but single PTE allocation on ARM, ia32 and x64.
-//
-// The layout of the super page is as follows. The sizes below are the same
-// for 32 bit and 64 bit.
-//
-//   | Guard page (4KB)    |
-//   | Metadata page (4KB) |
-//   | Guard pages (8KB)   |
-//   | Slot span           |
-//   | Slot span           |
-//   | ...                 |
-//   | Slot span           |
-//   | Guard page (4KB)    |
-//
-//   - Each slot span is a contiguous range of one or more PartitionPages.
-//   - The metadata page has the following format. Note that the PartitionPage
-//     that is not at the head of a slot span is "unused". In other words,
-//     the metadata for the slot span is stored only in the first PartitionPage
-//     of the slot span. Metadata accesses to other PartitionPages are
-//     redirected to the first PartitionPage.
-//
-//     | SuperPageExtentEntry (32B)                 |
-//     | PartitionPage of slot span 1 (32B, used)   |
-//     | PartitionPage of slot span 1 (32B, unused) |
-//     | PartitionPage of slot span 1 (32B, unused) |
-//     | PartitionPage of slot span 2 (32B, used)   |
-//     | PartitionPage of slot span 3 (32B, used)   |
-//     | ...                                        |
-//     | PartitionPage of slot span N (32B, unused) |
-//
-// A direct mapped page has a similar layout to fake it looking like a super
-// page:
-//
-//     | Guard page (4KB)     |
-//     | Metadata page (4KB)  |
-//     | Guard pages (8KB)    |
-//     | Direct mapped object |
-//     | Guard page (4KB)     |
-//
-//    - The metadata page has the following layout:
-//
-//     | SuperPageExtentEntry (32B)    |
-//     | PartitionPage (32B)           |
-//     | PartitionBucket (32B)         |
-//     | PartitionDirectMapExtent (8B) |
-static const size_t kSuperPageShift = 21;  // 2MB
-static const size_t kSuperPageSize = 1 << kSuperPageShift;
-static const size_t kSuperPageOffsetMask = kSuperPageSize - 1;
-static const size_t kSuperPageBaseMask = ~kSuperPageOffsetMask;
-static const size_t kNumPartitionPagesPerSuperPage =
-    kSuperPageSize / kPartitionPageSize;
-
-static const size_t kPageMetadataShift = 5;  // 32 bytes per partition page.
-static const size_t kPageMetadataSize = 1 << kPageMetadataShift;
-
-// The following kGeneric* constants apply to the generic variants of the API.
-// The "order" of an allocation is closely related to the power-of-two size of
-// the allocation. More precisely, the order is the bit index of the
-// most-significant-bit in the allocation size, where the bit numbers starts
-// at index 1 for the least-significant-bit.
-// In terms of allocation sizes, order 0 covers 0, order 1 covers 1, order 2
-// covers 2->3, order 3 covers 4->7, order 4 covers 8->15.
-static const size_t kGenericMinBucketedOrder = 4;  // 8 bytes.
-static const size_t kGenericMaxBucketedOrder =
-    20;  // Largest bucketed order is 1<<(20-1) (storing 512KB -> almost 1MB)
-static const size_t kGenericNumBucketedOrders =
-    (kGenericMaxBucketedOrder - kGenericMinBucketedOrder) + 1;
-// Eight buckets per order (for the higher orders), e.g. order 8 is 128, 144,
-// 160, ..., 240:
-static const size_t kGenericNumBucketsPerOrderBits = 3;
-static const size_t kGenericNumBucketsPerOrder =
-    1 << kGenericNumBucketsPerOrderBits;
-static const size_t kGenericNumBuckets =
-    kGenericNumBucketedOrders * kGenericNumBucketsPerOrder;
-static const size_t kGenericSmallestBucket = 1
-                                             << (kGenericMinBucketedOrder - 1);
-static const size_t kGenericMaxBucketSpacing =
-    1 << ((kGenericMaxBucketedOrder - 1) - kGenericNumBucketsPerOrderBits);
-static const size_t kGenericMaxBucketed =
-    (1 << (kGenericMaxBucketedOrder - 1)) +
-    ((kGenericNumBucketsPerOrder - 1) * kGenericMaxBucketSpacing);
-static const size_t kGenericMinDirectMappedDownsize =
-    kGenericMaxBucketed +
-    1;  // Limit when downsizing a direct mapping using realloc().
-static const size_t kGenericMaxDirectMapped = INT_MAX - kSystemPageSize;
-static const size_t kBitsPerSizet = sizeof(void*) * CHAR_BIT;
-
-// Constants for the memory reclaim logic.
-static const size_t kMaxFreeableSpans = 16;
-
-// If the total size in bytes of allocated but not committed pages exceeds this
-// value (probably it is a "out of virtual address space" crash),
-// a special crash stack trace is generated at |partitionOutOfMemory|.
-// This is to distinguish "out of virtual address space" from
-// "out of physical memory" in crash reports.
-static const size_t kReasonableSizeOfUnusedPages = 1024 * 1024 * 1024;  // 1GiB
-
-#if ENABLE(ASSERT)
-// These two byte values match tcmalloc.
-static const unsigned char kUninitializedByte = 0xAB;
-static const unsigned char kFreedByte = 0xCD;
-static const size_t kCookieSize =
-    16;  // Handles alignment up to XMM instructions on Intel.
-static const unsigned char kCookieValue[kCookieSize] = {
-    0xDE, 0xAD, 0xBE, 0xEF, 0xCA, 0xFE, 0xD0, 0x0D,
-    0x13, 0x37, 0xF0, 0x05, 0xBA, 0x11, 0xAB, 0x1E};
-#endif
-
-struct PartitionBucket;
-struct PartitionRootBase;
-
-struct PartitionFreelistEntry {
-  PartitionFreelistEntry* next;
-};
-
-// Some notes on page states. A page can be in one of four major states:
-// 1) Active.
-// 2) Full.
-// 3) Empty.
-// 4) Decommitted.
-// An active page has available free slots. A full page has no free slots. An
-// empty page has no free slots, and a decommitted page is an empty page that
-// had its backing memory released back to the system.
-// There are two linked lists tracking the pages. The "active page" list is an
-// approximation of a list of active pages. It is an approximation because
-// full, empty and decommitted pages may briefly be present in the list until
-// we next do a scan over it.
-// The "empty page" list is an accurate list of pages which are either empty
-// or decommitted.
-//
-// The significant page transitions are:
-// - free() will detect when a full page has a slot free()'d and immediately
-// return the page to the head of the active list.
-// - free() will detect when a page is fully emptied. It _may_ add it to the
-// empty list or it _may_ leave it on the active list until a future list scan.
-// - malloc() _may_ scan the active page list in order to fulfil the request.
-// If it does this, full, empty and decommitted pages encountered will be
-// booted out of the active list. If there are no suitable active pages found,
-// an empty or decommitted page (if one exists) will be pulled from the empty
-// list on to the active list.
-struct PartitionPage {
-  PartitionFreelistEntry* freelistHead;
-  PartitionPage* nextPage;
-  PartitionBucket* bucket;
-  // Deliberately signed, 0 for empty or decommitted page, -n for full pages:
-  int16_t numAllocatedSlots;
-  uint16_t numUnprovisionedSlots;
-  uint16_t pageOffset;
-  int16_t emptyCacheIndex;  // -1 if not in the empty cache.
-};
-
-struct PartitionBucket {
-  PartitionPage* activePagesHead;  // Accessed most in hot path => goes first.
-  PartitionPage* emptyPagesHead;
-  PartitionPage* decommittedPagesHead;
-  uint32_t slotSize;
-  unsigned numSystemPagesPerSlotSpan : 8;
-  unsigned numFullPages : 24;
-};
-
-// An "extent" is a span of consecutive superpages. We link to the partition's
-// next extent (if there is one) at the very start of a superpage's metadata
-// area.
-struct PartitionSuperPageExtentEntry {
-  PartitionRootBase* root;
-  char* superPageBase;
-  char* superPagesEnd;
-  PartitionSuperPageExtentEntry* next;
-};
-
-struct PartitionDirectMapExtent {
-  PartitionDirectMapExtent* nextExtent;
-  PartitionDirectMapExtent* prevExtent;
-  PartitionBucket* bucket;
-  size_t mapSize;  // Mapped size, not including guard pages and meta-data.
-};
-
-struct WTF_EXPORT PartitionRootBase {
-  size_t totalSizeOfCommittedPages;
-  size_t totalSizeOfSuperPages;
-  size_t totalSizeOfDirectMappedPages;
-  // Invariant: totalSizeOfCommittedPages <=
-  //                totalSizeOfSuperPages + totalSizeOfDirectMappedPages.
-  unsigned numBuckets;
-  unsigned maxAllocation;
-  bool initialized;
-  char* nextSuperPage;
-  char* nextPartitionPage;
-  char* nextPartitionPageEnd;
-  PartitionSuperPageExtentEntry* currentExtent;
-  PartitionSuperPageExtentEntry* firstExtent;
-  PartitionDirectMapExtent* directMapList;
-  PartitionPage* globalEmptyPageRing[kMaxFreeableSpans];
-  int16_t globalEmptyPageRingIndex;
-  uintptr_t invertedSelf;
-
-  static SpinLock gInitializedLock;
-  static bool gInitialized;
-  // gSeedPage is used as a sentinel to indicate that there is no page
-  // in the active page list. We can use nullptr, but in that case we need
-  // to add a null-check branch to the hot allocation path. We want to avoid
-  // that.
-  static PartitionPage gSeedPage;
-  static PartitionBucket gPagedBucket;
-  // gOomHandlingFunction is invoked when ParitionAlloc hits OutOfMemory.
-  static void (*gOomHandlingFunction)();
-};
-
-// Never instantiate a PartitionRoot directly, instead use PartitionAlloc.
-struct PartitionRoot : public PartitionRootBase {
-  // The PartitionAlloc templated class ensures the following is correct.
-  ALWAYS_INLINE PartitionBucket* buckets() {
-    return reinterpret_cast<PartitionBucket*>(this + 1);
-  }
-  ALWAYS_INLINE const PartitionBucket* buckets() const {
-    return reinterpret_cast<const PartitionBucket*>(this + 1);
-  }
-};
-
-// Never instantiate a PartitionRootGeneric directly, instead use
-// PartitionAllocatorGeneric.
-struct PartitionRootGeneric : public PartitionRootBase {
-  SpinLock lock;
-  // Some pre-computed constants.
-  size_t orderIndexShifts[kBitsPerSizet + 1];
-  size_t orderSubIndexMasks[kBitsPerSizet + 1];
-  // The bucket lookup table lets us map a size_t to a bucket quickly.
-  // The trailing +1 caters for the overflow case for very large allocation
-  // sizes.  It is one flat array instead of a 2D array because in the 2D
-  // world, we'd need to index array[blah][max+1] which risks undefined
-  // behavior.
-  PartitionBucket*
-      bucketLookups[((kBitsPerSizet + 1) * kGenericNumBucketsPerOrder) + 1];
-  PartitionBucket buckets[kGenericNumBuckets];
-};
-
-// Flags for partitionAllocGenericFlags.
-enum PartitionAllocFlags {
-  PartitionAllocReturnNull = 1 << 0,
-};
-
-// Struct used to retrieve total memory usage of a partition. Used by
-// PartitionStatsDumper implementation.
-struct PartitionMemoryStats {
-  size_t totalMmappedBytes;        // Total bytes mmaped from the system.
-  size_t totalCommittedBytes;      // Total size of commmitted pages.
-  size_t totalResidentBytes;       // Total bytes provisioned by the partition.
-  size_t totalActiveBytes;         // Total active bytes in the partition.
-  size_t totalDecommittableBytes;  // Total bytes that could be decommitted.
-  size_t totalDiscardableBytes;    // Total bytes that could be discarded.
-};
-
-// Struct used to retrieve memory statistics about a partition bucket. Used by
-// PartitionStatsDumper implementation.
-struct PartitionBucketMemoryStats {
-  bool isValid;      // Used to check if the stats is valid.
-  bool isDirectMap;  // True if this is a direct mapping; size will not be
-                     // unique.
-  uint32_t bucketSlotSize;       // The size of the slot in bytes.
-  uint32_t allocatedPageSize;    // Total size the partition page allocated from
-                                 // the system.
-  uint32_t activeBytes;          // Total active bytes used in the bucket.
-  uint32_t residentBytes;        // Total bytes provisioned in the bucket.
-  uint32_t decommittableBytes;   // Total bytes that could be decommitted.
-  uint32_t discardableBytes;     // Total bytes that could be discarded.
-  uint32_t numFullPages;         // Number of pages with all slots allocated.
-  uint32_t numActivePages;       // Number of pages that have at least one
-                                 // provisioned slot.
-  uint32_t numEmptyPages;        // Number of pages that are empty
-                                 // but not decommitted.
-  uint32_t numDecommittedPages;  // Number of pages that are empty
-                                 // and decommitted.
-};
-
-// Interface that is passed to partitionDumpStats and
-// partitionDumpStatsGeneric for using the memory statistics.
-class WTF_EXPORT PartitionStatsDumper {
- public:
-  // Called to dump total memory used by partition, once per partition.
-  virtual void partitionDumpTotals(const char* partitionName,
-                                   const PartitionMemoryStats*) = 0;
-
-  // Called to dump stats about buckets, for each bucket.
-  virtual void partitionsDumpBucketStats(const char* partitionName,
-                                         const PartitionBucketMemoryStats*) = 0;
-};
-
-WTF_EXPORT void partitionAllocGlobalInit(void (*oomHandlingFunction)());
-WTF_EXPORT void partitionAllocInit(PartitionRoot*,
-                                   size_t numBuckets,
-                                   size_t maxAllocation);
-WTF_EXPORT bool partitionAllocShutdown(PartitionRoot*);
-WTF_EXPORT void partitionAllocGenericInit(PartitionRootGeneric*);
-WTF_EXPORT bool partitionAllocGenericShutdown(PartitionRootGeneric*);
-
-enum PartitionPurgeFlags {
-  // Decommitting the ring list of empty pages is reasonably fast.
-  PartitionPurgeDecommitEmptyPages = 1 << 0,
-  // Discarding unused system pages is slower, because it involves walking all
-  // freelists in all active partition pages of all buckets >= system page
-  // size. It often frees a similar amount of memory to decommitting the empty
-  // pages, though.
-  PartitionPurgeDiscardUnusedSystemPages = 1 << 1,
-};
-
-WTF_EXPORT void partitionPurgeMemory(PartitionRoot*, int);
-WTF_EXPORT void partitionPurgeMemoryGeneric(PartitionRootGeneric*, int);
-
-WTF_EXPORT NEVER_INLINE void* partitionAllocSlowPath(PartitionRootBase*,
-                                                     int,
-                                                     size_t,
-                                                     PartitionBucket*);
-WTF_EXPORT NEVER_INLINE void partitionFreeSlowPath(PartitionPage*);
-WTF_EXPORT NEVER_INLINE void* partitionReallocGeneric(PartitionRootGeneric*,
-                                                      void*,
-                                                      size_t,
-                                                      const char* typeName);
-
-WTF_EXPORT void partitionDumpStats(PartitionRoot*,
-                                   const char* partitionName,
-                                   bool isLightDump,
-                                   PartitionStatsDumper*);
-WTF_EXPORT void partitionDumpStatsGeneric(PartitionRootGeneric*,
-                                          const char* partitionName,
-                                          bool isLightDump,
-                                          PartitionStatsDumper*);
-
-class WTF_EXPORT PartitionAllocHooks {
- public:
-  typedef void AllocationHook(void* address, size_t, const char* typeName);
-  typedef void FreeHook(void* address);
-
-  static void setAllocationHook(AllocationHook* hook) {
-    m_allocationHook = hook;
-  }
-  static void setFreeHook(FreeHook* hook) { m_freeHook = hook; }
-
-  static void allocationHookIfEnabled(void* address,
-                                      size_t size,
-                                      const char* typeName) {
-    AllocationHook* allocationHook = m_allocationHook;
-    if (UNLIKELY(allocationHook != nullptr))
-      allocationHook(address, size, typeName);
-  }
-
-  static void freeHookIfEnabled(void* address) {
-    FreeHook* freeHook = m_freeHook;
-    if (UNLIKELY(freeHook != nullptr))
-      freeHook(address);
-  }
-
-  static void reallocHookIfEnabled(void* oldAddress,
-                                   void* newAddress,
-                                   size_t size,
-                                   const char* typeName) {
-    // Report a reallocation as a free followed by an allocation.
-    AllocationHook* allocationHook = m_allocationHook;
-    FreeHook* freeHook = m_freeHook;
-    if (UNLIKELY(allocationHook && freeHook)) {
-      freeHook(oldAddress);
-      allocationHook(newAddress, size, typeName);
-    }
-  }
-
- private:
-  // Pointers to hook functions that PartitionAlloc will call on allocation and
-  // free if the pointers are non-null.
-  static AllocationHook* m_allocationHook;
-  static FreeHook* m_freeHook;
-};
-
-// In official builds, do not include type info string literals to avoid
-// bloating the binary.
-#if defined(OFFICIAL_BUILD)
-#define WTF_HEAP_PROFILER_TYPE_NAME(T) nullptr
-#else
-#define WTF_HEAP_PROFILER_TYPE_NAME(T) ::WTF::getStringWithTypeName<T>()
-#endif
-
-ALWAYS_INLINE PartitionFreelistEntry* partitionFreelistMask(
-    PartitionFreelistEntry* ptr) {
-// We use bswap on little endian as a fast mask for two reasons:
-// 1) If an object is freed and its vtable used where the attacker doesn't
-// get the chance to run allocations between the free and use, the vtable
-// dereference is likely to fault.
-// 2) If the attacker has a linear buffer overflow and elects to try and
-// corrupt a freelist pointer, partial pointer overwrite attacks are
-// thwarted.
-// For big endian, similar guarantees are arrived at with a negation.
-#if CPU(BIG_ENDIAN)
-  uintptr_t masked = ~reinterpret_cast<uintptr_t>(ptr);
-#else
-  uintptr_t masked = bswapuintptrt(reinterpret_cast<uintptr_t>(ptr));
-#endif
-  return reinterpret_cast<PartitionFreelistEntry*>(masked);
-}
-
-ALWAYS_INLINE size_t partitionCookieSizeAdjustAdd(size_t size) {
-#if ENABLE(ASSERT)
-  // Add space for cookies, checking for integer overflow.
-  ASSERT(size + (2 * kCookieSize) > size);
-  size += 2 * kCookieSize;
-#endif
-  return size;
-}
-
-ALWAYS_INLINE size_t partitionCookieSizeAdjustSubtract(size_t size) {
-#if ENABLE(ASSERT)
-  // Remove space for cookies.
-  ASSERT(size >= 2 * kCookieSize);
-  size -= 2 * kCookieSize;
-#endif
-  return size;
-}
-
-ALWAYS_INLINE void* partitionCookieFreePointerAdjust(void* ptr) {
-#if ENABLE(ASSERT)
-  // The value given to the application is actually just after the cookie.
-  ptr = static_cast<char*>(ptr) - kCookieSize;
-#endif
-  return ptr;
-}
-
-ALWAYS_INLINE void partitionCookieWriteValue(void* ptr) {
-#if ENABLE(ASSERT)
-  unsigned char* cookiePtr = reinterpret_cast<unsigned char*>(ptr);
-  for (size_t i = 0; i < kCookieSize; ++i, ++cookiePtr)
-    *cookiePtr = kCookieValue[i];
-#endif
-}
-
-ALWAYS_INLINE void partitionCookieCheckValue(void* ptr) {
-#if ENABLE(ASSERT)
-  unsigned char* cookiePtr = reinterpret_cast<unsigned char*>(ptr);
-  for (size_t i = 0; i < kCookieSize; ++i, ++cookiePtr)
-    ASSERT(*cookiePtr == kCookieValue[i]);
-#endif
-}
-
-ALWAYS_INLINE char* partitionSuperPageToMetadataArea(char* ptr) {
-  uintptr_t pointerAsUint = reinterpret_cast<uintptr_t>(ptr);
-  ASSERT(!(pointerAsUint & kSuperPageOffsetMask));
-  // The metadata area is exactly one system page (the guard page) into the
-  // super page.
-  return reinterpret_cast<char*>(pointerAsUint + kSystemPageSize);
-}
-
-ALWAYS_INLINE PartitionPage* partitionPointerToPageNoAlignmentCheck(void* ptr) {
-  uintptr_t pointerAsUint = reinterpret_cast<uintptr_t>(ptr);
-  char* superPagePtr =
-      reinterpret_cast<char*>(pointerAsUint & kSuperPageBaseMask);
-  uintptr_t partitionPageIndex =
-      (pointerAsUint & kSuperPageOffsetMask) >> kPartitionPageShift;
-  // Index 0 is invalid because it is the metadata and guard area and
-  // the last index is invalid because it is a guard page.
-  ASSERT(partitionPageIndex);
-  ASSERT(partitionPageIndex < kNumPartitionPagesPerSuperPage - 1);
-  PartitionPage* page = reinterpret_cast<PartitionPage*>(
-      partitionSuperPageToMetadataArea(superPagePtr) +
-      (partitionPageIndex << kPageMetadataShift));
-  // Partition pages in the same slot span can share the same page object.
-  // Adjust for that.
-  size_t delta = page->pageOffset << kPageMetadataShift;
-  page =
-      reinterpret_cast<PartitionPage*>(reinterpret_cast<char*>(page) - delta);
-  return page;
-}
-
-ALWAYS_INLINE void* partitionPageToPointer(const PartitionPage* page) {
-  uintptr_t pointerAsUint = reinterpret_cast<uintptr_t>(page);
-  uintptr_t superPageOffset = (pointerAsUint & kSuperPageOffsetMask);
-  ASSERT(superPageOffset > kSystemPageSize);
-  ASSERT(superPageOffset < kSystemPageSize + (kNumPartitionPagesPerSuperPage *
-                                              kPageMetadataSize));
-  uintptr_t partitionPageIndex =
-      (superPageOffset - kSystemPageSize) >> kPageMetadataShift;
-  // Index 0 is invalid because it is the metadata area and the last index is
-  // invalid because it is a guard page.
-  ASSERT(partitionPageIndex);
-  ASSERT(partitionPageIndex < kNumPartitionPagesPerSuperPage - 1);
-  uintptr_t superPageBase = (pointerAsUint & kSuperPageBaseMask);
-  void* ret = reinterpret_cast<void*>(
-      superPageBase + (partitionPageIndex << kPartitionPageShift));
-  return ret;
-}
-
-ALWAYS_INLINE PartitionPage* partitionPointerToPage(void* ptr) {
-  PartitionPage* page = partitionPointerToPageNoAlignmentCheck(ptr);
-  // Checks that the pointer is a multiple of bucket size.
-  ASSERT(!((reinterpret_cast<uintptr_t>(ptr) -
-            reinterpret_cast<uintptr_t>(partitionPageToPointer(page))) %
-           page->bucket->slotSize));
-  return page;
-}
-
-ALWAYS_INLINE bool partitionBucketIsDirectMapped(
-    const PartitionBucket* bucket) {
-  return !bucket->numSystemPagesPerSlotSpan;
-}
-
-ALWAYS_INLINE size_t partitionBucketBytes(const PartitionBucket* bucket) {
-  return bucket->numSystemPagesPerSlotSpan * kSystemPageSize;
-}
-
-ALWAYS_INLINE uint16_t partitionBucketSlots(const PartitionBucket* bucket) {
-  return static_cast<uint16_t>(partitionBucketBytes(bucket) / bucket->slotSize);
-}
-
-ALWAYS_INLINE size_t* partitionPageGetRawSizePtr(PartitionPage* page) {
-  // For single-slot buckets which span more than one partition page, we
-  // have some spare metadata space to store the raw allocation size. We
-  // can use this to report better statistics.
-  PartitionBucket* bucket = page->bucket;
-  if (bucket->slotSize <= kMaxSystemPagesPerSlotSpan * kSystemPageSize)
-    return nullptr;
-
-  ASSERT((bucket->slotSize % kSystemPageSize) == 0);
-  ASSERT(partitionBucketIsDirectMapped(bucket) ||
-         partitionBucketSlots(bucket) == 1);
-  page++;
-  return reinterpret_cast<size_t*>(&page->freelistHead);
-}
-
-ALWAYS_INLINE size_t partitionPageGetRawSize(PartitionPage* page) {
-  size_t* rawSizePtr = partitionPageGetRawSizePtr(page);
-  if (UNLIKELY(rawSizePtr != nullptr))
-    return *rawSizePtr;
-  return 0;
-}
-
-ALWAYS_INLINE PartitionRootBase* partitionPageToRoot(PartitionPage* page) {
-  PartitionSuperPageExtentEntry* extentEntry =
-      reinterpret_cast<PartitionSuperPageExtentEntry*>(
-          reinterpret_cast<uintptr_t>(page) & kSystemPageBaseMask);
-  return extentEntry->root;
-}
-
-ALWAYS_INLINE bool partitionPointerIsValid(void* ptr) {
-  PartitionPage* page = partitionPointerToPage(ptr);
-  PartitionRootBase* root = partitionPageToRoot(page);
-  return root->invertedSelf == ~reinterpret_cast<uintptr_t>(root);
-}
-
-ALWAYS_INLINE void* partitionBucketAlloc(PartitionRootBase* root,
-                                         int flags,
-                                         size_t size,
-                                         PartitionBucket* bucket) {
-  PartitionPage* page = bucket->activePagesHead;
-  // Check that this page is neither full nor freed.
-  ASSERT(page->numAllocatedSlots >= 0);
-  void* ret = page->freelistHead;
-  if (LIKELY(ret != 0)) {
-    // If these asserts fire, you probably corrupted memory.
-    ASSERT(partitionPointerIsValid(ret));
-    // All large allocations must go through the slow path to correctly
-    // update the size metadata.
-    ASSERT(partitionPageGetRawSize(page) == 0);
-    PartitionFreelistEntry* newHead =
-        partitionFreelistMask(static_cast<PartitionFreelistEntry*>(ret)->next);
-    page->freelistHead = newHead;
-    page->numAllocatedSlots++;
-  } else {
-    ret = partitionAllocSlowPath(root, flags, size, bucket);
-    ASSERT(!ret || partitionPointerIsValid(ret));
-  }
-#if ENABLE(ASSERT)
-  if (!ret)
-    return 0;
-  // Fill the uninitialized pattern, and write the cookies.
-  page = partitionPointerToPage(ret);
-  size_t slotSize = page->bucket->slotSize;
-  size_t rawSize = partitionPageGetRawSize(page);
-  if (rawSize) {
-    ASSERT(rawSize == size);
-    slotSize = rawSize;
-  }
-  size_t noCookieSize = partitionCookieSizeAdjustSubtract(slotSize);
-  char* charRet = static_cast<char*>(ret);
-  // The value given to the application is actually just after the cookie.
-  ret = charRet + kCookieSize;
-  memset(ret, kUninitializedByte, noCookieSize);
-  partitionCookieWriteValue(charRet);
-  partitionCookieWriteValue(charRet + kCookieSize + noCookieSize);
-#endif
-  return ret;
-}
-
-ALWAYS_INLINE void* partitionAlloc(PartitionRoot* root,
-                                   size_t size,
-                                   const char* typeName) {
-#if defined(MEMORY_TOOL_REPLACES_ALLOCATOR)
-  void* result = malloc(size);
-  RELEASE_ASSERT(result);
-  return result;
-#else
-  size_t requestedSize = size;
-  size = partitionCookieSizeAdjustAdd(size);
-  ASSERT(root->initialized);
-  size_t index = size >> kBucketShift;
-  ASSERT(index < root->numBuckets);
-  ASSERT(size == index << kBucketShift);
-  PartitionBucket* bucket = &root->buckets()[index];
-  void* result = partitionBucketAlloc(root, 0, size, bucket);
-  PartitionAllocHooks::allocationHookIfEnabled(result, requestedSize, typeName);
-  return result;
-#endif  // defined(MEMORY_TOOL_REPLACES_ALLOCATOR)
-}
-
-ALWAYS_INLINE void partitionFreeWithPage(void* ptr, PartitionPage* page) {
-// If these asserts fire, you probably corrupted memory.
-#if ENABLE(ASSERT)
-  size_t slotSize = page->bucket->slotSize;
-  size_t rawSize = partitionPageGetRawSize(page);
-  if (rawSize)
-    slotSize = rawSize;
-  partitionCookieCheckValue(ptr);
-  partitionCookieCheckValue(reinterpret_cast<char*>(ptr) + slotSize -
-                            kCookieSize);
-  memset(ptr, kFreedByte, slotSize);
-#endif
-  ASSERT(page->numAllocatedSlots);
-  PartitionFreelistEntry* freelistHead = page->freelistHead;
-  ASSERT(!freelistHead || partitionPointerIsValid(freelistHead));
-  SECURITY_CHECK(ptr != freelistHead);  // Catches an immediate double free.
-  // Look for double free one level deeper in debug.
-  SECURITY_DCHECK(!freelistHead ||
-                  ptr != partitionFreelistMask(freelistHead->next));
-  PartitionFreelistEntry* entry = static_cast<PartitionFreelistEntry*>(ptr);
-  entry->next = partitionFreelistMask(freelistHead);
-  page->freelistHead = entry;
-  --page->numAllocatedSlots;
-  if (UNLIKELY(page->numAllocatedSlots <= 0)) {
-    partitionFreeSlowPath(page);
-  } else {
-    // All single-slot allocations must go through the slow path to
-    // correctly update the size metadata.
-    ASSERT(partitionPageGetRawSize(page) == 0);
-  }
-}
-
-ALWAYS_INLINE void partitionFree(void* ptr) {
-#if defined(MEMORY_TOOL_REPLACES_ALLOCATOR)
-  free(ptr);
-#else
-  PartitionAllocHooks::freeHookIfEnabled(ptr);
-  ptr = partitionCookieFreePointerAdjust(ptr);
-  ASSERT(partitionPointerIsValid(ptr));
-  PartitionPage* page = partitionPointerToPage(ptr);
-  partitionFreeWithPage(ptr, page);
-#endif
-}
-
-ALWAYS_INLINE PartitionBucket* partitionGenericSizeToBucket(
-    PartitionRootGeneric* root,
-    size_t size) {
-  size_t order = kBitsPerSizet - CountLeadingZeroBitsSizeT(size);
-  // The order index is simply the next few bits after the most significant bit.
-  size_t orderIndex = (size >> root->orderIndexShifts[order]) &
-                      (kGenericNumBucketsPerOrder - 1);
-  // And if the remaining bits are non-zero we must bump the bucket up.
-  size_t subOrderIndex = size & root->orderSubIndexMasks[order];
-  PartitionBucket* bucket =
-      root->bucketLookups[(order << kGenericNumBucketsPerOrderBits) +
-                          orderIndex + !!subOrderIndex];
-  ASSERT(!bucket->slotSize || bucket->slotSize >= size);
-  ASSERT(!(bucket->slotSize % kGenericSmallestBucket));
-  return bucket;
-}
-
-ALWAYS_INLINE void* partitionAllocGenericFlags(PartitionRootGeneric* root,
-                                               int flags,
-                                               size_t size,
-                                               const char* typeName) {
-#if defined(MEMORY_TOOL_REPLACES_ALLOCATOR)
-  void* result = malloc(size);
-  RELEASE_ASSERT(result || flags & PartitionAllocReturnNull);
-  return result;
-#else
-  ASSERT(root->initialized);
-  size_t requestedSize = size;
-  size = partitionCookieSizeAdjustAdd(size);
-  PartitionBucket* bucket = partitionGenericSizeToBucket(root, size);
-  void* ret = nullptr;
-  {
-    SpinLock::Guard guard(root->lock);
-    ret = partitionBucketAlloc(root, flags, size, bucket);
-  }
-  PartitionAllocHooks::allocationHookIfEnabled(ret, requestedSize, typeName);
-  return ret;
-#endif
-}
-
-ALWAYS_INLINE void* partitionAllocGeneric(PartitionRootGeneric* root,
-                                          size_t size,
-                                          const char* typeName) {
-  return partitionAllocGenericFlags(root, 0, size, typeName);
-}
-
-ALWAYS_INLINE void partitionFreeGeneric(PartitionRootGeneric* root, void* ptr) {
-#if defined(MEMORY_TOOL_REPLACES_ALLOCATOR)
-  free(ptr);
-#else
-  ASSERT(root->initialized);
-
-  if (UNLIKELY(!ptr))
-    return;
-
-  PartitionAllocHooks::freeHookIfEnabled(ptr);
-  ptr = partitionCookieFreePointerAdjust(ptr);
-  ASSERT(partitionPointerIsValid(ptr));
-  PartitionPage* page = partitionPointerToPage(ptr);
-  {
-    SpinLock::Guard guard(root->lock);
-    partitionFreeWithPage(ptr, page);
-  }
-#endif
-}
-
-ALWAYS_INLINE size_t partitionDirectMapSize(size_t size) {
-  // Caller must check that the size is not above the kGenericMaxDirectMapped
-  // limit before calling. This also guards against integer overflow in the
-  // calculation here.
-  ASSERT(size <= kGenericMaxDirectMapped);
-  return (size + kSystemPageOffsetMask) & kSystemPageBaseMask;
-}
-
-ALWAYS_INLINE size_t partitionAllocActualSize(PartitionRootGeneric* root,
-                                              size_t size) {
-#if defined(MEMORY_TOOL_REPLACES_ALLOCATOR)
-  return size;
-#else
-  ASSERT(root->initialized);
-  size = partitionCookieSizeAdjustAdd(size);
-  PartitionBucket* bucket = partitionGenericSizeToBucket(root, size);
-  if (LIKELY(!partitionBucketIsDirectMapped(bucket))) {
-    size = bucket->slotSize;
-  } else if (size > kGenericMaxDirectMapped) {
-    // Too large to allocate => return the size unchanged.
-  } else {
-    ASSERT(bucket == &PartitionRootBase::gPagedBucket);
-    size = partitionDirectMapSize(size);
-  }
-  return partitionCookieSizeAdjustSubtract(size);
-#endif
-}
-
-ALWAYS_INLINE bool partitionAllocSupportsGetSize() {
-#if defined(MEMORY_TOOL_REPLACES_ALLOCATOR)
-  return false;
-#else
-  return true;
-#endif
-}
-
-ALWAYS_INLINE size_t partitionAllocGetSize(void* ptr) {
-  // No need to lock here. Only 'ptr' being freed by another thread could
-  // cause trouble, and the caller is responsible for that not happening.
-  ASSERT(partitionAllocSupportsGetSize());
-  ptr = partitionCookieFreePointerAdjust(ptr);
-  ASSERT(partitionPointerIsValid(ptr));
-  PartitionPage* page = partitionPointerToPage(ptr);
-  size_t size = page->bucket->slotSize;
-  return partitionCookieSizeAdjustSubtract(size);
-}
-
-// N (or more accurately, N - sizeof(void*)) represents the largest size in
-// bytes that will be handled by a SizeSpecificPartitionAllocator.
-// Attempts to partitionAlloc() more than this amount will fail.
-template <size_t N>
-class SizeSpecificPartitionAllocator {
- public:
-  static const size_t kMaxAllocation = N - kAllocationGranularity;
-  static const size_t kNumBuckets = N / kAllocationGranularity;
-  void init() {
-    partitionAllocInit(&m_partitionRoot, kNumBuckets, kMaxAllocation);
-  }
-  bool shutdown() { return partitionAllocShutdown(&m_partitionRoot); }
-  ALWAYS_INLINE PartitionRoot* root() { return &m_partitionRoot; }
-
- private:
-  PartitionRoot m_partitionRoot;
-  PartitionBucket m_actualBuckets[kNumBuckets];
-};
-
-class PartitionAllocatorGeneric {
- public:
-  void init() { partitionAllocGenericInit(&m_partitionRoot); }
-  bool shutdown() { return partitionAllocGenericShutdown(&m_partitionRoot); }
-  ALWAYS_INLINE PartitionRootGeneric* root() { return &m_partitionRoot; }
-
- private:
-  PartitionRootGeneric m_partitionRoot;
-};
-
-}  // namespace WTF
-
-using WTF::SizeSpecificPartitionAllocator;
-using WTF::PartitionAllocatorGeneric;
-using WTF::PartitionRoot;
-using WTF::partitionAllocInit;
-using WTF::partitionAllocShutdown;
-using WTF::partitionAlloc;
-using WTF::partitionFree;
-using WTF::partitionAllocGeneric;
-using WTF::partitionFreeGeneric;
-using WTF::partitionReallocGeneric;
-using WTF::partitionAllocActualSize;
-using WTF::partitionAllocSupportsGetSize;
-using WTF::partitionAllocGetSize;
-
-#endif  // WTF_PartitionAlloc_h