Refactors CPU feature detection.

runtime/vm/cpuinfo_macos.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_MACOS)
+
+#include "vm/cpuinfo.h"
+
+#include <errno.h>  // NOLINT
+#include <sys/types.h>  // NOLINT
+#include <sys/sysctl.h>  // NOLINT
+
+#include "platform/assert.h"
+
+namespace dart {
+
+char* CpuInfo::data_ = NULL;
+intptr_t CpuInfo::datalen_ = 0;
+
+// No-op on MacOS.
+void CpuInfo::InitOnce() {}
+
+
+bool CpuInfo::FieldContains(const char* field, const char* search_string) {
+  ASSERT(search_string != NULL);
+  char dest[1024];
+  size_t dest_len = 1024;
+
+  ASSERT(HasField(field));
+  if (sysctlbyname(field, dest, &dest_len, NULL, 0) != 0) {
+    UNREACHABLE();
+    return false;
+  }
+
+  return (strcasestr(dest, search_string) != NULL);
+}
+
+
+char* CpuInfo::ExtractField(const char* field) {
+  ASSERT(field != NULL);
+  size_t result_len;
+
+  ASSERT(HasField(field));
+  if (sysctlbyname(field, NULL, &result_len, NULL, 0) != 0) {
+    UNREACHABLE();
+    return 0;
+  }
+
+  char* result = new char[result_len];
+  if (sysctlbyname(field, result, &result_len, NULL, 0) != 0) {
+    UNREACHABLE();
+    return 0;
+  }
+
+  return result;
+}
+
+
+bool CpuInfo::HasField(const char* field) {
+  ASSERT(field != NULL);
+  int ret = sysctlbyname(field, NULL, NULL, NULL, 0);
+  return (ret != ENOENT);
+}
+
+
+const char *CpuInfo::fields_[] = {

[Ivan Posva, 2014/01/21 21:41:02]

How about adding index values for these fields?

[zra, 2014/01/24 21:18:27]

Unfortunately, there are no designated initializers in C++, but what I've done
is written a function called from InitOnce to fill in the fields_ array using
the index value enums.

+  "machdep.cpu.vendor",
+  "machdep.cpu.brand_string",

[Cutch, 2014/01/15 20:50:49]

Wouldn't it be better if the field names were abstracted? That way the calling
code doesn't have to care about which OS it's running on.

[zra, 2014/01/24 21:18:27]

There is an abstracted interface through the enum in the header file. I wanted
to also expose the string-based interface for development/experimentation before
adding new fields to the enum.

+  "machdep.cpu.features",
+};
+
+}  // namespace dart
+
+#endif  // defined(TARGET_OS_MACOS)