Reland of "[heap] Parallel newspace evacuation, semispace copy, and compaction \o/"

src/globals.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_GLOBALS_H_
 #define V8_GLOBALS_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 1040 matching lines @@
   DCHECK(IsValidFunctionKind(kind));
   return kind & FunctionKind::kInObjectLiteral;
 }
 
 
 inline FunctionKind WithObjectLiteralBit(FunctionKind kind) {
   kind = static_cast<FunctionKind>(kind | FunctionKind::kInObjectLiteral);
   DCHECK(IsValidFunctionKind(kind));
   return kind;
 }
+
+inline uint32_t ObjectHash(Address address) {
+  // All objects are at least pointer aligned, so we can remove the trailing
+  // zeros.
+  return static_cast<uint32_t>(bit_cast<uintptr_t>(address) >>
+                               kPointerSizeLog2);
+}
+
 }  // namespace internal
 }  // namespace v8
 
 namespace i = v8::internal;
 
 #endif  // V8_GLOBALS_H_