Add flag for turning off initializing variables with loops

include/GLSLANG/ShaderLang.h

@@ -25,7 +25,7 @@
 
 // Version number for shader translation API.
 // It is incremented every time the API changes.
-#define ANGLE_SH_VERSION 187
+#define ANGLE_SH_VERSION 188
 
 enum ShShaderSpec
 {
@@ -253,6 +253,10 @@ const ShCompileOptions SH_CLAMP_POINT_SIZE = UINT64_C(1) << 35;
 // driver version 387.92. It works around the most common occurrences of the bug.
 const ShCompileOptions SH_REWRITE_VECTOR_SCALAR_ARITHMETIC = UINT64_C(1) << 36;
 
+// Don't use loops to initialize uninitialized variables. Only has an effect if some kind of
+// variable initialization is turned on.
+const ShCompileOptions SH_DONT_USE_LOOPS_TO_INITIALIZE_VARIABLES = UINT64_C(1) << 37;
+
 // Defines alternate strategies for implementing array index clamping.
 enum ShArrayIndexClampingStrategy
 {

src/libANGLE/renderer/gl/ShaderGL.cpp

@@ -122,6 +122,11 @@ ShCompileOptions ShaderGL::prepareSourceAndReturnOptions(std::stringstream *sour
         options |= SH_REWRITE_VECTOR_SCALAR_ARITHMETIC;
     }
 
+    if (mWorkarounds.dontUseLoopsToInitializeVariables)
+    {
+        options |= SH_DONT_USE_LOOPS_TO_INITIALIZE_VARIABLES;
+    }
+
     if (mMultiviewImplementationType == MultiviewImplementationTypeGL::NV_VIEWPORT_ARRAY2)
     {
         options |= SH_INITIALIZE_BUILTINS_FOR_INSTANCED_MULTIVIEW;

src/libANGLE/renderer/gl/WorkaroundsGL.h

@@ -138,6 +138,9 @@ struct WorkaroundsGL
     // executed incorrectly. Change them in the shader translator. Tracking bug:
     // http://crbug.com/772651
     bool rewriteVectorScalarArithmetic = false;
+
+    // On some Android devices for loops used to initialize variables hit native GLSL compiler bugs.
+    bool dontUseLoopsToInitializeVariables = false;
 };
 }  // namespace rx
 

src/libANGLE/renderer/gl/renderergl_utils.cpp

@@ -1114,6 +1114,8 @@ void GenerateWorkarounds(const FunctionsGL *functions, WorkaroundsGL *workaround
     workarounds->reapplyUBOBindingsAfterUsingBinaryProgram = true;
 
     workarounds->clampPointSize = true;
+
+    workarounds->dontUseLoopsToInitializeVariables = !IsNvidia(vendor);
 #endif
 }