MAINT-3131 Discard improbably high memory bandwidth measurements on OSX and default to Class 3

indra/newview/llfeaturemanager.cpp

@@ -426,7 +426,10 @@ bool LLFeatureManager::loadGPUClass()
 
 	if (gbps < 0.f)
 	{ //couldn't bench, use GLVersion
-
+#if LL_DARWIN
+        //GLVersion is misleading on OSX, just default to class 3 if we can't bench
+        mGPUClass = GPU_CLASS_3;
+#else
 		if (gGLManager.mGLVersion < 2.f)
 		{
 			mGPUClass = GPU_CLASS_0;
@@ -447,6 +450,7 @@ bool LLFeatureManager::loadGPUClass()
 		{
 			mGPUClass = GPU_CLASS_4;
 		}
+#endif
 	}
 	else if (gbps < 5.f)
 	{

indra/newview/llglsandbox.cpp

@@ -928,7 +928,7 @@ F32 gpu_benchmark()
 	std::vector<F32> results;
 
 	//build a random texture
-	U8 pixels[res*res*4];
+	U8* pixels = new U8[res*res*4];
 
 	for (U32 i = 0; i < res*res*4; ++i)
 	{
@@ -950,6 +950,8 @@ F32 gpu_benchmark()
 		LLImageGL::setManualImage(GL_TEXTURE_2D, 0, GL_RGBA, res,res,GL_RGBA, GL_UNSIGNED_BYTE, pixels);
 	}
 
+    delete [] pixels;
+
 	//make a dummy triangle to draw with
 	LLPointer<LLVertexBuffer> buff = new LLVertexBuffer(LLVertexBuffer::MAP_VERTEX | LLVertexBuffer::MAP_TEXCOORD0, GL_STATIC_DRAW_ARB);
 	buff->allocateBuffer(3, 0, true);
@@ -1032,6 +1034,15 @@ F32 gpu_benchmark()
 
 	LL_INFOS() << "Memory bandwidth is " << llformat("%.3f", gbps) << "GB/sec according to CPU timers" << LL_ENDL;
   
+#if LL_DARWIN
+    if (gbps > 512.f)
+    { 
+        LL_INFOS() << "Memory bandwidth is improbably high and likely incorrect." << LL_ENDL;
+        //OSX is probably lying, discard result
+        gbps = -1.f;
+    }
+#endif
+
 	if (gGLManager.mHasTimerQuery)
 	{
 		F32 ms = gBenchmarkProgram.mTimeElapsed/1000000.f;