Switch wtf/SpinLock to std::atomic

third_party/WebKit/Source/wtf/PartitionAlloc.h

 /*
  * 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
@@ skipping 291 matching lines @@
     char* nextSuperPage;
     char* nextPartitionPage;
     char* nextPartitionPageEnd;
     PartitionSuperPageExtentEntry* currentExtent;
     PartitionSuperPageExtentEntry* firstExtent;
     PartitionDirectMapExtent* directMapList;
     PartitionPage* globalEmptyPageRing[kMaxFreeableSpans];
     int16_t globalEmptyPageRingIndex;
     uintptr_t invertedSelf;
 
-    static int gInitializedLock;
+    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 {
-    int lock;
+    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];
 };
@@ skipping 401 matching lines @@
 {
 #if defined(MEMORY_TOOL_REPLACES_ALLOCATOR)
     void* result = malloc(size);
     RELEASE_ASSERT(result);
     return result;
 #else
     ASSERT(root->initialized);
     size_t requestedSize = size;
     size = partitionCookieSizeAdjustAdd(size);
     PartitionBucket* bucket = partitionGenericSizeToBucket(root, size);
-    spinLockLock(&root->lock);
-    // TODO(bashi): Remove following RELEAE_ASSERT()s once we find the cause of
-    // http://crbug.com/514141
+    void* ret = nullptr;
+    {
+        SpinLock::Guard guard(root->lock);
+        // TODO(bashi): Remove following RELEAE_ASSERT()s once we find the cause of
+        // http://crbug.com/514141
 #if OS(ANDROID)
-    RELEASE_ASSERT(bucket >= &root->buckets[0] || bucket == &PartitionRootGeneric::gPagedBucket);
-    RELEASE_ASSERT(bucket <= &root->buckets[kGenericNumBuckets - 1] || bucket == &PartitionRootGeneric::gPagedBucket);
-    RELEASE_ASSERT(root->initialized);
+        RELEASE_ASSERT(bucket >= &root->buckets[0] || bucket == &PartitionRootGeneric::gPagedBucket);
+        RELEASE_ASSERT(bucket <= &root->buckets[kGenericNumBuckets - 1] || bucket == &PartitionRootGeneric::gPagedBucket);
+        RELEASE_ASSERT(root->initialized);
 #endif
-    void* ret = partitionBucketAlloc(root, flags, size, bucket);
-    spinLockUnlock(&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);
-    spinLockLock(&root->lock);
-    partitionFreeWithPage(ptr, page);
-    spinLockUnlock(&root->lock);
+    {
+        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;
@@ skipping 75 matching lines @@
 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