import FIREFOX_52_6_0esr_RELEASE from mozilla-esr52 hg repo

mozglue/build/mips.cpp

@@ -0,0 +1,47 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* compile-time and runtime tests for whether to use MIPS-specific extensions */
+
+#include "mips.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+enum{
+  MIPS_FLAG_LOONGSON3 = 1,
+};
+
+static unsigned
+get_mips_cpu_flags(void)
+{
+  unsigned  flags = 0;
+  FILE     *fin;
+
+  fin = fopen("/proc/cpuinfo","r");
+  if (fin != nullptr) {
+    char buf[1024];
+    memset(buf, 0, sizeof(buf));
+    fread(buf, sizeof(char), sizeof(buf) - 1, fin);
+    fclose(fin);
+    if (strstr(buf, "Loongson-3"))
+        flags |= MIPS_FLAG_LOONGSON3;
+  }
+  return flags;
+}
+
+static bool
+check_loongson3(void)
+{
+  // Cache a local copy so we only have to read /proc/cpuinfo once.
+  static unsigned mips_cpu_flags = get_mips_cpu_flags();
+  return (mips_cpu_flags & MIPS_FLAG_LOONGSON3) != 0;
+}
+
+namespace mozilla {
+  namespace mips_private {
+    bool isLoongson3 = check_loongson3();
+  } // namespace mips_private
+} // namespace mozilla