Revert "translator: Reject shaders that use both FragColor+FragData."

src/compiler/translator/ParseContext.cpp

@@ -1049,27 +1049,6 @@ const TVariable *TParseContext::getNamedVariable(const TSourceLoc &location,
         {
             recover();
         }
-
-        // Reject shaders using both gl_FragData and gl_FragColor
-        TQualifier qualifier = variable->getType().getQualifier();
-        if (qualifier == EvqFragData)
-        {
-            mUsesFragData = true;
-        }
-        else if (qualifier == EvqFragColor)
-        {
-            mUsesFragColor = true;
-        }
-
-        // This validation is not quite correct - it's only an error to write to
-        // both FragData and FragColor. For simplicity, and because users shouldn't
-        // be rewarded for reading from undefined varaibles, return an error
-        // if they are both referenced, rather than assigned.
-        if (mUsesFragData && mUsesFragColor)
-        {
-            error(location, "cannot use both gl_FragData and gl_FragColor", name->c_str());
-            recover();
-        }
     }
 
     if (!variable)

src/compiler/translator/ParseContext.h

@@ -56,9 +56,7 @@ class TParseContext : angle::NonCopyable
           mDirectiveHandler(ext, mDiagnostics, mShaderVersion, debugShaderPrecisionSupported),
           mPreprocessor(&mDiagnostics, &mDirectiveHandler),
           mScanner(nullptr),
-          mDeferredSingleDeclarationErrorCheck(false),
-          mUsesFragData(false),
-          mUsesFragColor(false)
+          mDeferredSingleDeclarationErrorCheck(false)
     {
     }
 
@@ -75,7 +73,6 @@ class TParseContext : angle::NonCopyable
                const char *extraInfo="");
     void warning(const TSourceLoc &loc, const char *reason, const char *token,
                  const char *extraInfo="");
-
     void recover();
     TIntermNode *getTreeRoot() const { return mTreeRoot; }
     void setTreeRoot(TIntermNode *treeRoot) { mTreeRoot = treeRoot; }
@@ -342,8 +339,6 @@ class TParseContext : angle::NonCopyable
     TDirectiveHandler mDirectiveHandler;
     pp::Preprocessor mPreprocessor;
     void *mScanner;
-    bool mUsesFragData; // track if we are using both gl_FragData and gl_FragColor
-    bool mUsesFragColor;
 };
 
 int PaParseStrings(

src/libANGLE/renderer/d3d/DynamicHLSL.cpp

@@ -757,8 +757,11 @@ bool DynamicHLSL::generateShaderLinkHLSL(const gl::Data &data, InfoLog &infoLog,
     bool usesPointSize = vertexShader->mUsesPointSize;
     bool useInstancedPointSpriteEmulation = usesPointSize && mRenderer->getWorkarounds().useInstancedPointSpriteEmulation;
 
-    // Validation done in the compiler
-    ASSERT(!usesFragColor || !usesFragData);
+    if (usesFragColor && usesFragData)
+    {
+        infoLog << "Cannot use both gl_FragColor and gl_FragData in the same fragment shader.";
+        return false;
+    }
 
     // Write the HLSL input/output declarations
     const int shaderModel = mRenderer->getMajorShaderModel();

src/tests/compiler_tests/MalformedShader_test.cpp

@@ -545,20 +545,3 @@ TEST_F(MalformedShaderTest, AssignConstGlobalToGlobal)
         FAIL() << "Shader compilation failed, expecting success " << mInfoLog;
     }
 }
-
-// Statically assigning to both gl_FragData and gl_FragColor is forbidden (ESSL 1.00 section 7.2)
-TEST_F(MalformedShaderTest, WriteBothFragDataAndFragColor)
-{
-    const std::string &shaderString =
-        "precision mediump float;\n"
-        "void foo() {\n"
-        "   gl_FragData[0].a++;\n"
-        "}\n"
-        "void main() {\n"
-        "   gl_FragColor.x += 0.0;\n"
-        "}\n";
-    if (compile(shaderString))
-    {
-        FAIL() << "Shader compilation succeeded, expecting failure " << mInfoLog;
-    }
-}