commit 14e95b384f9dc6f0afbefd7f87aaf8ce4d6f225f
author Jamie Madill <jmadill@chromium.org> Thu May 07 10:10:41 2015 -0400
committer Jamie Madill <jmadill@chromium.org> Fri May 15 14:41:09 2015 +0000
tree 1f0409ef6e25a22fb49fb00991db87d4aaef911e
parent 0ea959f4004cb2b09be60d4e46507002c65b0d42

translator: Reject shaders that use both FragColor+FragData.

*re-land with fix for unused var in release*

We checked this at link time in the D3D back-end, but this
restriction applies to all shaders.

TEST=dEQP-GLES2.functional.shaders.fragdata.*
BUG=angleproject:995
BUG=478572

Change-Id: I63258f4de47e658812822f31601cc235f48c0826
Reviewed-on: https://chromium-review.googlesource.com/271470
Tested-by: Jamie Madill <jmadill@chromium.org>
Reviewed-by: Olli Etuaho <oetuaho@nvidia.com>
Reviewed-by: Geoff Lang <geofflang@chromium.org>

src/compiler/translator/ParseContext.cpp

diff --git a/src/compiler/translator/ParseContext.cpp b/src/compiler/translator/ParseContext.cpp
index 784032d..a9e9516 100644
--- a/src/compiler/translator/ParseContext.cpp
+++ b/src/compiler/translator/ParseContext.cpp
@@ -1049,6 +1049,27 @@
         {
             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

diff --git a/src/compiler/translator/ParseContext.h b/src/compiler/translator/ParseContext.h
index bdf290c..d7885d8 100644
--- a/src/compiler/translator/ParseContext.h
+++ b/src/compiler/translator/ParseContext.h
@@ -56,7 +56,9 @@
           mDirectiveHandler(ext, mDiagnostics, mShaderVersion, debugShaderPrecisionSupported),
           mPreprocessor(&mDiagnostics, &mDirectiveHandler),
           mScanner(nullptr),
-          mDeferredSingleDeclarationErrorCheck(false)
+          mDeferredSingleDeclarationErrorCheck(false),
+          mUsesFragData(false),
+          mUsesFragColor(false)
     {
     }
 
@@ -73,6 +75,7 @@
                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; }
@@ -339,6 +342,8 @@
     TDirectiveHandler mDirectiveHandler;
     pp::Preprocessor mPreprocessor;
     void *mScanner;
+    bool mUsesFragData; // track if we are using both gl_FragData and gl_FragColor
+    bool mUsesFragColor;
 };
 
 int PaParseStrings(