Refactors CPU feature detection.

runtime/vm/cpuinfo_win.cc

+// 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.
+
+#include "vm/globals.h"
+#if defined(TARGET_OS_WINDOWS)
+
+// __cpuid()
+#include <intrin.h>  // NOLINT
+
+#include "vm/cpuinfo.h"
+
+#include "platform/assert.h"
+
+namespace dart {
+
+char* CpuInfo::data_ = NULL;
+intptr_t CpuInfo::datalen_ = 0;
+
+void CpuInfo::Read() {}
+
+
+bool CpuInfo::FieldContains(const char* field, const char* search_string) {
+  UNIMPLEMENTED();
+  return false;
+}
+
+
+intptr_t CpuInfo::ExtractField(
+    const char* field, char* dest, const intptr_t dest_len) {
+  UNIMPLEMENTED();
+  return 0;
+}
+
+
+bool CpuInfo::HasField(const char* field) {
+  UNIMPLEMENTED();
+  return 0;
+}
+
+
+intptr_t CpuInfo::GetCpuModel(char* dest, const intptr_t dest_len) {
+  ASSERT(dest != NULL);
+  ASSERT(dest_len >= 3 * 4 * sizeof(int32_t));
+  int32_t info[4] = {-1};
+  intptr_t i, num_ids = 0;
+
+  // The documentation for __cpuid is at:
+  // http://msdn.microsoft.com/en-us/library/hskdteyh(v=vs.90).aspx
+  // TODO(zra): In Read() above, read and cache more entries using __cpuid,
+  // then extract as in the implementations for other OS's.
+  dest[0] = '\0';
+  __cpuid(info, 0x80000000);
+  num_ids = info[0];
+  for (i = 0x80000000; i <= num_ids; i++) {
+    __cpuid(info, i);
+    if ((i == 0x80000002) || (i == 0x80000003) || (i == 0x80000004)) {
+      intptr_t off = (i - 0x80000002) * 4 * sizeof(int32_t);
+      char* chunk = reinterpret_cast<char*>(info);
+      for (int j = 0; j < 4 * sizeof(int32_t); j++) {
+        dest[off + j] = chunk[j];
+      }
+    }
+    if (i >= 0x80000004) {
+      break;
+    }
+  }
+
+  return strlen(dest);
+}
+
+}  // namespace dart
+
+#endif  // defined(TARGET_OS_WINDOWS)