Implement a fast buffer allocator for Vector, HashTable and StringBuilder

Source/wtf/Vector.h

Index: Source/wtf/Vector.h
diff --git a/Source/wtf/Vector.h b/Source/wtf/Vector.h
index 15d15e3bc9070821b743abd0231669f26ab4b277..f79f116a567af54c3ed5928594e09bfb70242670 100644
--- a/Source/wtf/Vector.h
+++ b/Source/wtf/Vector.h
@@ -32,6 +32,7 @@
 #include "wtf/VectorTraits.h"
 #include <algorithm>
 #include <iterator>
+#include <stdio.h>
 #include <string.h>
 #include <utility>
 
@@ -319,9 +320,9 @@ static const size_t kInitialVectorSize = WTF_VECTOR_INITIAL_SIZE;
             ASSERT(newCapacity);
             size_t sizeToAllocate = allocationSize(newCapacity);
             if (hasInlineCapacity)
-                m_buffer = Allocator::template allocateInlineVectorBacking<T>(sizeToAllocate);
+                m_buffer = Allocator::template allocateInlineVectorBacking<T>(sizeToAllocate, this);
             else
-                m_buffer = Allocator::template allocateVectorBacking<T>(sizeToAllocate);
+                m_buffer = Allocator::template allocateVectorBacking<T>(sizeToAllocate, this);
             m_capacity = sizeToAllocate / sizeof(T);
         }
 
@@ -330,15 +331,15 @@ static const size_t kInitialVectorSize = WTF_VECTOR_INITIAL_SIZE;
             ASSERT(newCapacity);
             size_t sizeToAllocate = allocationSize(newCapacity);
             if (hasInlineCapacity)
-                m_buffer = Allocator::template allocateInlineVectorBacking<T>(sizeToAllocate);
+                m_buffer = Allocator::template allocateInlineVectorBacking<T>(sizeToAllocate, this);
             else
-                m_buffer = Allocator::template allocateExpandedVectorBacking<T>(sizeToAllocate);
+                m_buffer = Allocator::template allocateExpandedVectorBacking<T>(sizeToAllocate, this);
             m_capacity = sizeToAllocate / sizeof(T);
         }
 
         size_t allocationSize(size_t capacity) const
         {
-            return Allocator::template quantizedSize<T>(capacity);
+            return Allocator::template quantizedSize(capacity, sizeof(T));
         }
 
         T* buffer() { return m_buffer; }
@@ -413,7 +414,7 @@ static const size_t kInitialVectorSize = WTF_VECTOR_INITIAL_SIZE;
         bool expandBuffer(size_t newCapacity)
         {
             size_t sizeToAllocate = allocationSize(newCapacity);
-            if (Allocator::expandVectorBacking(m_buffer, sizeToAllocate)) {
+            if (Allocator::expandVectorBacking(m_buffer, sizeToAllocate + 16)) {
                 m_capacity = sizeToAllocate / sizeof(T);
                 return true;
             }
@@ -1050,10 +1051,7 @@ static const size_t kInitialVectorSize = WTF_VECTOR_INITIAL_SIZE;
 #ifdef ANNOTATE_CONTIGUOUS_CONTAINER
         size_t oldCapacity = capacity();
 #endif
-        // The Allocator::isGarbageCollected check is not needed.
-        // The check is just a static hint for a compiler to indicate that
-        // Base::expandBuffer returns false if Allocator is a DefaultAllocator.
-        if (Allocator::isGarbageCollected && Base::expandBuffer(newCapacity)) {
+        if (Base::expandBuffer(newCapacity)) {
             ANNOTATE_CHANGE_CAPACITY(begin(), oldCapacity, m_size, capacity());
             return;
         }