Revert of Try using std::call_once

src/opts/opts_check_x86.cpp

Index: src/opts/opts_check_x86.cpp
diff --git a/src/opts/opts_check_x86.cpp b/src/opts/opts_check_x86.cpp
index 23f30364a595aa18b1e57dd785ac83567204d6cd..3c817e1f0a4e529c0d9cf1212b2ed257f439ed3b 100644
--- a/src/opts/opts_check_x86.cpp
+++ b/src/opts/opts_check_x86.cpp
@@ -13,8 +13,8 @@
 #include "SkBlitRow.h"
 #include "SkBlitRow_opts_SSE2.h"
 #include "SkBlitRow_opts_SSE4.h"
+#include "SkOncePtr.h"
 #include "SkRTConf.h"
-#include <mutex>
 
 #if defined(_MSC_VER) && defined(_WIN64)
 #include <intrin.h>
@@ -68,12 +68,37 @@
 
 ////////////////////////////////////////////////////////////////////////////////
 
+/* Fetch the SIMD level directly from the CPU, at run-time.
+ * Only checks the levels needed by the optimizations in this file.
+ */
+static int* get_SIMD_level() {
+    int cpu_info[4] = { 0, 0, 0, 0 };
+    getcpuid(1, cpu_info);
+
+    int* level = new int;
+
+    if ((cpu_info[2] & (1<<20)) != 0) {
+        *level = SK_CPU_SSE_LEVEL_SSE42;
+    } else if ((cpu_info[2] & (1<<19)) != 0) {
+        *level = SK_CPU_SSE_LEVEL_SSE41;
+    } else if ((cpu_info[2] & (1<<9)) != 0) {
+        *level = SK_CPU_SSE_LEVEL_SSSE3;
+    } else if ((cpu_info[3] & (1<<26)) != 0) {
+        *level = SK_CPU_SSE_LEVEL_SSE2;
+    } else {
+        *level = 0;
+    }
+    return level;
+}
+
+SK_DECLARE_STATIC_ONCE_PTR(int, gSIMDLevel);
+
 /* Verify that the requested SIMD level is supported in the build.
  * If not, check if the platform supports it.
  */
-static inline bool supports_simd(int level) {
+static inline bool supports_simd(int minLevel) {
 #if defined(SK_CPU_SSE_LEVEL)
-    if (level <= SK_CPU_SSE_LEVEL) {
+    if (minLevel <= SK_CPU_SSE_LEVEL) {
         return true;
     } else
 #endif
@@ -87,18 +112,7 @@
          */
         return false;
 #else
-        static std::once_flag once;
-        static int maxLevel = 0;
-        std::call_once(once, [&]{
-            int cpu_info[4] = { 0, 0, 0, 0 };
-            getcpuid(1, cpu_info);
-
-            if (cpu_info[3] & (1<<26)) { maxLevel = SK_CPU_SSE_LEVEL_SSE2 ; }
-            if (cpu_info[2] & (1<< 9)) { maxLevel = SK_CPU_SSE_LEVEL_SSSE3; }
-            if (cpu_info[2] & (1<<19)) { maxLevel = SK_CPU_SSE_LEVEL_SSE41; }
-            if (cpu_info[2] & (1<<20)) { maxLevel = SK_CPU_SSE_LEVEL_SSE42; }
-        });
-        return level <= maxLevel;
+        return minLevel <= *gSIMDLevel.get(get_SIMD_level);
 #endif
     }
 }