michael@0: //
michael@0: // Copyright (c) 2012 The ANGLE Project Authors. All rights reserved.
michael@0: // Use of this source code is governed by a BSD-style license that can be
michael@0: // found in the LICENSE file.
michael@0: //
michael@0: 
michael@0: #include "compiler/InfoSink.h"
michael@0: #include "compiler/ParseHelper.h"
michael@0: #include "compiler/depgraph/DependencyGraphOutput.h"
michael@0: #include "compiler/timing/RestrictFragmentShaderTiming.h"
michael@0: 
michael@0: RestrictFragmentShaderTiming::RestrictFragmentShaderTiming(TInfoSinkBase& sink)
michael@0:     : mSink(sink)
michael@0:     , mNumErrors(0)
michael@0: {
michael@0:     // Sampling ops found only in fragment shaders.
michael@0:     mSamplingOps.insert("texture2D(s21;vf2;f1;");
michael@0:     mSamplingOps.insert("texture2DProj(s21;vf3;f1;");
michael@0:     mSamplingOps.insert("texture2DProj(s21;vf4;f1;");
michael@0:     mSamplingOps.insert("textureCube(sC1;vf3;f1;");
michael@0:     // Sampling ops found in both vertex and fragment shaders.
michael@0:     mSamplingOps.insert("texture2D(s21;vf2;");
michael@0:     mSamplingOps.insert("texture2DProj(s21;vf3;");
michael@0:     mSamplingOps.insert("texture2DProj(s21;vf4;");
michael@0:     mSamplingOps.insert("textureCube(sC1;vf3;");
michael@0:     // Sampling ops provided by OES_EGL_image_external.
michael@0:     mSamplingOps.insert("texture2D(1;vf2;");
michael@0:     mSamplingOps.insert("texture2DProj(1;vf3;");
michael@0:     mSamplingOps.insert("texture2DProj(1;vf4;");
michael@0:     // Sampling ops provided by ARB_texture_rectangle.
michael@0:     mSamplingOps.insert("texture2DRect(1;vf2;");
michael@0:     mSamplingOps.insert("texture2DRectProj(1;vf3;");
michael@0:     mSamplingOps.insert("texture2DRectProj(1;vf4;");
michael@0: }
michael@0: 
michael@0: // FIXME(mvujovic): We do not know if the execution time of built-in operations like sin, pow, etc.
michael@0: // can vary based on the value of the input arguments. If so, we should restrict those as well.
michael@0: void RestrictFragmentShaderTiming::enforceRestrictions(const TDependencyGraph& graph)
michael@0: {
michael@0:     mNumErrors = 0;
michael@0: 
michael@0:     // FIXME(mvujovic): The dependency graph does not support user defined function calls right now,
michael@0:     // so we generate errors for them.
michael@0:     validateUserDefinedFunctionCallUsage(graph);
michael@0: 
michael@0:     // Starting from each sampler, traverse the dependency graph and generate an error each time we
michael@0:     // hit a node where sampler dependent values are not allowed.
michael@0:     for (TGraphSymbolVector::const_iterator iter = graph.beginSamplerSymbols();
michael@0:          iter != graph.endSamplerSymbols();
michael@0:          ++iter)
michael@0:     {
michael@0:         TGraphSymbol* samplerSymbol = *iter;
michael@0:         clearVisited();
michael@0:         samplerSymbol->traverse(this);
michael@0:     }
michael@0: }
michael@0: 
michael@0: void RestrictFragmentShaderTiming::validateUserDefinedFunctionCallUsage(const TDependencyGraph& graph)
michael@0: {
michael@0:     for (TFunctionCallVector::const_iterator iter = graph.beginUserDefinedFunctionCalls();
michael@0:          iter != graph.endUserDefinedFunctionCalls();
michael@0:          ++iter)
michael@0:     {
michael@0:         TGraphFunctionCall* functionCall = *iter;
michael@0:         beginError(functionCall->getIntermFunctionCall());
michael@0:         mSink << "A call to a user defined function is not permitted.\n";
michael@0:     }
michael@0: }
michael@0: 
michael@0: void RestrictFragmentShaderTiming::beginError(const TIntermNode* node)
michael@0: {
michael@0:     ++mNumErrors;
michael@0:     mSink.prefix(EPrefixError);
michael@0:     mSink.location(node->getLine());
michael@0: }
michael@0: 
michael@0: bool RestrictFragmentShaderTiming::isSamplingOp(const TIntermAggregate* intermFunctionCall) const
michael@0: {
michael@0:     return !intermFunctionCall->isUserDefined() &&
michael@0:            mSamplingOps.find(intermFunctionCall->getName()) != mSamplingOps.end();
michael@0: }
michael@0: 
michael@0: void RestrictFragmentShaderTiming::visitArgument(TGraphArgument* parameter)
michael@0: {
michael@0:     // Texture cache access time might leak sensitive information.
michael@0:     // Thus, we restrict sampler dependent values from affecting the coordinate or LOD bias of a
michael@0:     // sampling operation.
michael@0:     if (isSamplingOp(parameter->getIntermFunctionCall())) {
michael@0:         switch (parameter->getArgumentNumber()) {
michael@0:             case 1:
michael@0:                 // Second argument (coord)
michael@0:                 beginError(parameter->getIntermFunctionCall());
michael@0:                 mSink << "An expression dependent on a sampler is not permitted to be the"
michael@0:                       << " coordinate argument of a sampling operation.\n";
michael@0:                 break;
michael@0:             case 2:
michael@0:                 // Third argument (bias)
michael@0:                 beginError(parameter->getIntermFunctionCall());
michael@0:                 mSink << "An expression dependent on a sampler is not permitted to be the"
michael@0:                       << " bias argument of a sampling operation.\n";
michael@0:                 break;
michael@0:             default:
michael@0:                 // First argument (sampler)
michael@0:                 break;
michael@0:         }
michael@0:     }
michael@0: }
michael@0: 
michael@0: void RestrictFragmentShaderTiming::visitSelection(TGraphSelection* selection)
michael@0: {
michael@0:     beginError(selection->getIntermSelection());
michael@0:     mSink << "An expression dependent on a sampler is not permitted in a conditional statement.\n";
michael@0: }
michael@0: 
michael@0: void RestrictFragmentShaderTiming::visitLoop(TGraphLoop* loop)
michael@0: {
michael@0:     beginError(loop->getIntermLoop());
michael@0:     mSink << "An expression dependent on a sampler is not permitted in a loop condition.\n";
michael@0: }
michael@0: 
michael@0: void RestrictFragmentShaderTiming::visitLogicalOp(TGraphLogicalOp* logicalOp)
michael@0: {
michael@0:     beginError(logicalOp->getIntermLogicalOp());
michael@0:     mSink << "An expression dependent on a sampler is not permitted on the left hand side of a logical "
michael@0:           << logicalOp->getOpString()
michael@0:           << " operator.\n";
michael@0: }