[runtime] Move AtomicIsLockFree out of Runtime class.

src/runtime/runtime-atomics.cc

 // Copyright 2015 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.
 
 #include "src/runtime/runtime-utils.h"
 
 #include "src/arguments.h"
 #include "src/base/macros.h"
 #include "src/base/platform/mutex.h"
 #include "src/conversions-inl.h"
 #include "src/factory.h"
 
 // Implement Atomic accesses to SharedArrayBuffers as defined in the
 // SharedArrayBuffer draft spec, found here
 // https://docs.google.com/document/d/1NDGA_gZJ7M7w1Bh8S0AoDyEqwDdRh4uSoTPSNn77PFk
 
 namespace v8 {
 namespace internal {
 
 namespace {
 
+// Assume that 32-bit architectures don't have 64-bit atomic ops.
+// TODO(binji): can we do better here?
+#if V8_TARGET_ARCH_64_BIT && V8_HOST_ARCH_64_BIT
+
+#define ATOMICS_REQUIRE_LOCK_64_BIT 0
+
+inline bool AtomicIsLockFree(uint32_t size) {
+  return size == 1 || size == 2 || size == 4 || size == 8;
+}
+
+#else
+
+#define ATOMICS_REQUIRE_LOCK_64_BIT 1
+
+inline bool AtomicIsLockFree(uint32_t size) {
+  return size == 1 || size == 2 || size == 4;
+}
+
+#endif
+
 #if V8_CC_GNU
 
 template <typename T>
 inline T CompareExchangeSeqCst(T* p, T oldval, T newval) {
   (void)__atomic_compare_exchange_n(p, &oldval, newval, 0, __ATOMIC_SEQ_CST,
                                     __ATOMIC_SEQ_CST);
   return oldval;
 }
 
 template <typename T>
@@ skipping 787 matching lines @@
   UNREACHABLE();
   return isolate->heap()->undefined_value();
 }
 
 
 RUNTIME_FUNCTION(Runtime_AtomicsIsLockFree) {
   HandleScope scope(isolate);
   DCHECK(args.length() == 1);
   CONVERT_NUMBER_ARG_HANDLE_CHECKED(size, 0);
   uint32_t usize = NumberToUint32(*size);
-
-  return Runtime::AtomicIsLockFree(usize) ? isolate->heap()->true_value()
-                                          : isolate->heap()->false_value();
+  return isolate->heap()->ToBoolean(AtomicIsLockFree(usize));
 }
 }
 }  // namespace v8::internal