Refactors CPU feature detection.

runtime/vm/cpu_ia32.h

Index: runtime/vm/cpu_ia32.h
===================================================================
--- runtime/vm/cpu_ia32.h	(revision 0)
+++ runtime/vm/cpu_ia32.h	(revision 0)
@@ -0,0 +1,38 @@
+// Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+#ifndef VM_CPU_IA32_H_
+#define VM_CPU_IA32_H_
+
+#include "vm/allocation.h"
+
+namespace dart {
+
+class CPUFeatures : public AllStatic {
+ public:
+  static void InitOnce();
+  // x64 always has at least SSE2.
+  static bool sse2_supported();
+  static bool sse4_1_supported();
+  static bool double_truncate_round_supported() { return sse4_1_supported(); }
+  static char* hardware();
+
+ private:
+  static const uint64_t kSSE2BitMask = static_cast<uint64_t>(1) << 26;

[Cutch, 2014/01/02 19:39:19]

Should this be here or inside the .cc file?

+  static const uint64_t kSSE4_1BitMask = static_cast<uint64_t>(1) << 51;
+
+  static bool sse2_supported_;
+  static bool sse4_1_supported_;
+
+#define HARDWARE_LEN 64

[Cutch, 2014/01/02 19:39:19]

This #define and hardware_ is repeated in all files, can it be factored into a
base class?

+  static char hardware_[HARDWARE_LEN];
+
+#if defined(DEBUG)
+  static bool initialized_;
+#endif
+};
+
+}  // namespace dart
+
+#endif  // VM_CPU_IA32_H_