[SH_TIMING_RESTRICTIONS] Restrict sampler dependent values from the tex coord and bias parameters of all sampling operations, not just texture2D.

Issue: 335
Review URL: https://codereview.appspot.com/6305049/


git-svn-id: https://angleproject.googlecode.com/svn/trunk@1167 736b8ea6-26fd-11df-bfd4-992fa37f6226

samples/translator/translator.cpp

@@ -117,6 +117,7 @@ int main(int argc, char* argv[])
                     switch (argv[0][3]) {
                     case 'i': resources.OES_EGL_image_external = 1; break;
                     case 'd': resources.OES_standard_derivatives = 1; break;
+                    case 'r': resources.ARB_texture_rectangle = 1; break;
                     default: failCode = EFailUsage;
                     }
                 } else {
@@ -220,7 +221,8 @@ void usage()
         "       -b=g     : output GLSL code\n"
         "       -b=h     : output HLSL code\n"
         "       -x=i     : enable GL_OES_EGL_image_external\n"
-        "       -x=d     : enable GL_OES_EGL_standard_derivatives\n");
+        "       -x=d     : enable GL_OES_EGL_standard_derivatives\n"
+        "       -x=r     : enable ARB_texture_rectangle\n");
 }
 
 //

src/compiler/timing/RestrictFragmentShaderTiming.cpp

@@ -9,6 +9,30 @@
 #include "compiler/depgraph/DependencyGraphOutput.h"
 #include "compiler/timing/RestrictFragmentShaderTiming.h"
 
+RestrictFragmentShaderTiming::RestrictFragmentShaderTiming(TInfoSinkBase& sink)
+    : mSink(sink)
+    , mNumErrors(0)
+{
+    // Sampling ops found only in fragment shaders.
+    mSamplingOps.insert("texture2D(s21;vf2;f1;");
+    mSamplingOps.insert("texture2DProj(s21;vf3;f1;");
+    mSamplingOps.insert("texture2DProj(s21;vf4;f1;");
+    mSamplingOps.insert("textureCube(sC1;vf3;f1;");
+    // Sampling ops found in both vertex and fragment shaders.
+    mSamplingOps.insert("texture2D(s21;vf2;");
+    mSamplingOps.insert("texture2DProj(s21;vf3;");
+    mSamplingOps.insert("texture2DProj(s21;vf4;");
+    mSamplingOps.insert("textureCube(sC1;vf3;");
+    // Sampling ops provided by OES_EGL_image_external.
+    mSamplingOps.insert("texture2D(1;vf2;");
+    mSamplingOps.insert("texture2DProj(1;vf3;");
+    mSamplingOps.insert("texture2DProj(1;vf4;");
+    // Sampling ops provided by ARB_texture_rectangle.
+    mSamplingOps.insert("texture2DRect(1;vf2;");
+    mSamplingOps.insert("texture2DRectProj(1;vf3;");
+    mSamplingOps.insert("texture2DRectProj(1;vf4;");
+}
+
 // FIXME(mvujovic): We do not know if the execution time of built-in operations like sin, pow, etc.
 // can vary based on the value of the input arguments. If so, we should restrict those as well.
 void RestrictFragmentShaderTiming::enforceRestrictions(const TDependencyGraph& graph)
@@ -50,18 +74,36 @@ void RestrictFragmentShaderTiming::beginError(const TIntermNode* node)
     mSink.location(node->getLine());
 }
 
+bool RestrictFragmentShaderTiming::isSamplingOp(const TIntermAggregate* intermFunctionCall) const
+{
+    return !intermFunctionCall->isUserDefined() &&
+           mSamplingOps.find(intermFunctionCall->getName()) != mSamplingOps.end();
+}
+
 void RestrictFragmentShaderTiming::visitArgument(TGraphArgument* parameter)
 {
-    // FIXME(mvujovic): We should restrict sampler dependent values from being texture coordinates 
-    // in all available sampling operations supported in GLSL ES.
-    // This includes overloaded signatures of texture2D, textureCube, and others.
-    if (parameter->getIntermFunctionCall()->getName() != "texture2D(s21;vf2;" ||
-        parameter->getArgumentNumber() != 1)
-        return;
-
-    beginError(parameter->getIntermFunctionCall());
-    mSink << "An expression dependent on a sampler is not permitted to be the second argument"
-          << " of a texture2D call.\n";
+    // Texture cache access time might leak sensitive information.
+    // Thus, we restrict sampler dependent values from affecting the coordinate or LOD bias of a
+    // sampling operation.
+    if (isSamplingOp(parameter->getIntermFunctionCall())) {
+        switch (parameter->getArgumentNumber()) {
+            case 1:
+                // Second argument (coord)
+                beginError(parameter->getIntermFunctionCall());
+                mSink << "An expression dependent on a sampler is not permitted to be the"
+                      << " coordinate argument of a sampling operation.\n";
+                break;
+            case 2:
+                // Third argument (bias)
+                beginError(parameter->getIntermFunctionCall());
+                mSink << "An expression dependent on a sampler is not permitted to be the"
+                      << " bias argument of a sampling operation.\n";
+                break;
+            default:
+                // First argument (sampler)
+                break;
+        }
+    }
 }
 
 void RestrictFragmentShaderTiming::visitSelection(TGraphSelection* selection)

src/compiler/timing/RestrictFragmentShaderTiming.h

@@ -16,10 +16,7 @@ class TInfoSinkBase;
 
 class RestrictFragmentShaderTiming : TDependencyGraphTraverser {
 public:
-    RestrictFragmentShaderTiming(TInfoSinkBase& sink)
-        : mSink(sink)
-        , mNumErrors(0) {}
-
+    RestrictFragmentShaderTiming(TInfoSinkBase& sink);
     void enforceRestrictions(const TDependencyGraph& graph);
     int numErrors() const { return mNumErrors; }
 
@@ -31,9 +28,13 @@ public:
 private:
     void beginError(const TIntermNode* node);
     void validateUserDefinedFunctionCallUsage(const TDependencyGraph& graph);
+    bool isSamplingOp(const TIntermAggregate* intermFunctionCall) const;
 
-	TInfoSinkBase& mSink;
+    TInfoSinkBase& mSink;
     int mNumErrors;
+
+    typedef std::set<TString> StringSet;
+    StringSet mSamplingOps;
 };
 
 #endif  // COMPILER_TIMING_RESTRICT_FRAGMENT_SHADER_TIMING_H_