Ensure we align zone memory at 8 byte boundaries on all platforms

src/zone/zone.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_ZONE_ZONE_H_
 #define V8_ZONE_ZONE_H_
 
 #include <limits>
 
 #include "src/base/hashmap.h"
@@ skipping 45 matching lines @@
     return segment_bytes_allocated_ > kExcessLimit;
   }
 
   const char* name() const { return name_; }
 
   size_t allocation_size() const { return allocation_size_; }
 
   AccountingAllocator* allocator() const { return allocator_; }
 
  private:
-// All pointers returned from New() have this alignment.  In addition, if the
-// object being allocated has a size that is divisible by 8 then its alignment
-// will be 8. ASan requires 8-byte alignment. MIPS also requires 8-byte
-// alignment.
-#if defined(V8_USE_ADDRESS_SANITIZER) || defined(V8_TARGET_ARCH_MIPS)
-  static const size_t kAlignment = 8;
-  STATIC_ASSERT(kPointerSize <= 8);
-#else
-  static const size_t kAlignment = kPointerSize;
-#endif
+  // All pointers returned from New() are 8-byte aligned.
+  static const size_t kAlignmentInBytes = 8;
 
   // Never allocate segments smaller than this size in bytes.
   static const size_t kMinimumSegmentSize = 8 * KB;
 
   // Never allocate segments larger than this size in bytes.
   static const size_t kMaximumSegmentSize = 1 * MB;
 
   // Report zone excess when allocation exceeds this limit.
   static const size_t kExcessLimit = 256 * MB;
 
@@ skipping 144 matching lines @@
 
 typedef base::PointerTemplateHashMapImpl<ZoneAllocationPolicy> ZoneHashMap;
 
 typedef base::CustomMatcherTemplateHashMapImpl<ZoneAllocationPolicy>
     CustomMatcherZoneHashMap;
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_ZONE_ZONE_H_