Bug 1256588 - IonMonkey: MIPS: Implement isLoongson. r=huangwenjun06

---
 .../jit/mips-shared/Architecture-mips-shared.cpp   | 29 ++++++++++++----------
 js/src/jit/mips-shared/Architecture-mips-shared.h  |  1 +
 2 files changed, 17 insertions(+), 13 deletions(-)

js/src/jit/mips-shared/Architecture-mips-shared.cpp

@@ -12,6 +12,7 @@
 #include "jit/RegisterSets.h"
 
 #define HWCAP_MIPS (1 << 31)
+#define HWCAP_LOONGSON (1 << 30)
 #define HWCAP_FPU (1 << 0)
 
 namespace js {
@@ -19,20 +20,19 @@ namespace jit {
 
 uint32_t GetMIPSFlags()
 {
-    static bool isSet = false;
     static uint32_t flags = 0;
-    if (isSet)
-        return flags;
-#if defined(JS_SIMULATOR_MIPS32) || defined(JS_SIMULATOR_MIPS64)
-    isSet = true;
-    flags |= HWCAP_FPU;
-    return flags;
-#else
 
-#ifdef __linux__
+    if (flags)
+        return flags;
+
+    flags |= HWCAP_MIPS;
+#if defined(JS_SIMULATOR_MIPS32) || defined(JS_SIMULATOR_MIPS64)
+    flags |= HWCAP_FPU;
+#else
+# ifdef __linux__
     FILE* fp = fopen("/proc/cpuinfo", "r");
     if (!fp)
-        return false;
+        return flags;
 
     char buf[1024];
     memset(buf, 0, sizeof(buf));
@@ -40,13 +40,11 @@ uint32_t GetMIPSFlags()
     fclose(fp);
     if (strstr(buf, "FPU"))
         flags |= HWCAP_FPU;
-
-    isSet = true;
-    return flags;
-#endif
-
-    return flags;
+    if (strstr(buf, "Loongson"))
+        flags |= HWCAP_LOONGSON;
+# endif
 #endif // JS_SIMULATOR_MIPS32 || JS_SIMULATOR_MIPS64
+    return flags;
 }
 
 bool hasFPU()
@@ -54,6 +52,11 @@ bool hasFPU()
     return js::jit::GetMIPSFlags() & HWCAP_FPU;
 }
 
+bool isLoongson()
+{
+    return js::jit::GetMIPSFlags() & HWCAP_LOONGSON;
+}
+
 Registers::Code
 Registers::FromName(const char* name)
 {

js/src/jit/mips-shared/Architecture-mips-shared.h

@@ -310,6 +310,7 @@ class FloatRegisterMIPSShared
 
 uint32_t GetMIPSFlags();
 bool hasFPU();
+bool isLoongson();
 
 // MIPS doesn't have double registers that can NOT be treated as float32.
 inline bool