Refactors CPU feature detection.

runtime/vm/cpuinfo_win.cc

Index: runtime/vm/cpuinfo_win.cc
===================================================================
--- runtime/vm/cpuinfo_win.cc	(revision 0)
+++ runtime/vm/cpuinfo_win.cc	(revision 0)
@@ -0,0 +1,115 @@
+// 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)
+
+#include "vm/cpuinfo.h"
+
+// __cpuid()
+#include <intrin.h>  // NOLINT
+#include <string.h>  // NOLINT
+
+#include "platform/assert.h"
+
+namespace dart {
+
+struct CpuIdData {
+  static bool sse2;
+  static bool sse41;
+  static char* id_string;
+  static char* brand_string;
+};
+
+
+char* CpuInfo::data_ = NULL;
+intptr_t CpuInfo::datalen_ = 0;
+bool CpuIdData::sse2 = false;
+bool CpuIdData::sse41 = false;
+char* CpuIdData::id_string = NULL;
+char* CpuIdData::brand_string = NULL;
+
+
+// The documentation for __cpuid is at:
+// http://msdn.microsoft.com/en-us/library/hskdteyh(v=vs.90).aspx
+// InitOnce reads and caches __cpuid results for use by CpuInfo.
+void CpuInfo::InitOnce() {
+  int32_t info[4] = {-1};
+
+  InitializeFields();
+
+  __cpuid(info, 0);
+  char *id_string = new char[3 * sizeof(int32_t)];
+  // Yes, these are supposed to be out of order.
+  *reinterpret_cast<int32_t*>(id_string) = info[1];
+  *reinterpret_cast<int32_t*>(id_string + 4) = info[3];
+  *reinterpret_cast<int32_t*>(id_string + 8) = info[2];
+  CpuIdData::id_string = id_string;
+
+  __cpuid(info, 1);
+  CpuIdData::sse41 = (info[2] & (1 << 19)) != 0;
+  CpuIdData::sse2 = (info[3] & (1 << 26)) != 0;
+
+  char* brand_string = new char[3 * 4 * sizeof(int32_t)];
+  for (intptr_t i = 0x80000002; i <= 0x80000004; i++) {
+    intptr_t off = (i - 0x80000002) * 4 * sizeof(int32_t);
+    __cpuid(info, i);
+    *reinterpret_cast<int32_t*>(brand_string + off) = info[0];
+    *reinterpret_cast<int32_t*>(brand_string + off + 4) = info[1];
+    *reinterpret_cast<int32_t*>(brand_string + off + 8) = info[2];
+    *reinterpret_cast<int32_t*>(brand_string + off + 12) = info[3];
+  }
+  CpuIdData::brand_string = brand_string;
+}
+
+
+bool CpuInfo::FieldContains(const char* field, const char* search_string) {
+  if (strcmp(field, fields_[kCpuInfoProcessor]) == 0) {
+    return strstr(CpuIdData::id_string, search_string);
+  } else if (strcmp(field, fields_[kCpuInfoModel]) == 0) {
+    return strstr(CpuIdData::brand_string, search_string);
+  } else if (strcmp(field, fields_[kCpuInfoFeatures]) == 0) {
+    if (strcmp(search_string, "sse2") == 0) {
+      return CpuIdData::sse2;
+    } else if (strcmp(search_string, "sse4.1") == 0) {
+      return CpuIdData::sse41;
+    } else {
+      return false;
+    }
+  } else {
+    UNIMPLEMENTED();
+  }
+  return false;
+}
+
+
+char* CpuInfo::ExtractField(const char* field) {
+  if (strcmp(field, fields_[kCpuInfoProcessor]) == 0) {
+    return CpuIdData::id_string;
+  } else if (strcmp(field, fields_[kCpuInfoModel]) == 0) {
+    return CpuIdData::brand_string;
+  } else {
+    UNIMPLEMENTED();
+  }
+  return NULL;
+}
+
+
+bool CpuInfo::HasField(const char* field) {
+  return (strcmp(field, fields_[kCpuInfoProcessor]) == 0) ||
+         (strcmp(field, fields_[kCpuInfoModel]) == 0) ||
+         (strcmp(field, fields_[kCpuInfoFeatures]) == 0);
+}
+
+
+const char* CpuInfo::fields_[kCpuInfoMax] = {0};
+void CpuInfo::InitializeFields() {
+  fields_[kCpuInfoProcessor] = "Processor";
+  fields_[kCpuInfoModel] = "Hardware";
+  fields_[kCpuInfoFeatures] = "Features";
+}
+
+}  // namespace dart
+
+#endif  // defined(TARGET_OS_WINDOWS)