Replace fWillReadFragmentPosition with a bitfield

src/gpu/glsl/GrGLSLFragmentShaderBuilder.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrGLSLFragmentShaderBuilder.h"
 #include "GrRenderTarget.h"
 #include "gl/GrGLGpu.h"
@@ skipping 56 matching lines @@
 }
 
 GrGLSLFragmentShaderBuilder::GrGLSLFragmentShaderBuilder(GrGLSLProgramBuilder* program,
                                                          uint8_t fragPosKey)
     : GrGLSLFragmentBuilder(program)
     , fSetupFragPosition(false)
     , fTopLeftFragPosRead(kTopLeftFragPosRead_FragPosKey == fragPosKey)
     , fHasCustomColorOutput(false)
     , fCustomColorOutputIndex(-1)
     , fHasSecondaryOutput(false)
-    , fHasInitializedSampleMask(false)
-    , fHasReadDstColor(false)
-    , fHasReadFragmentPosition(false) {
+    , fHasInitializedSampleMask(false) {
     fSubstageIndices.push_back(0);
+#ifdef SK_DEBUG
+    fUsedBuiltInState = GrProcessor::kNone_BuiltInState;
+    fHasReadDstColor = false;
+#endif
 }
 
 bool GrGLSLFragmentShaderBuilder::enableFeature(GLSLFeature feature) {
     switch (feature) {
         case kStandardDerivatives_GLSLFeature: {
             if (!fProgramBuilder->glslCaps()->shaderDerivativeSupport()) {
                 return false;
             }
             const char* extension = fProgramBuilder->glslCaps()->shaderDerivativeExtensionString();
             if (extension) {
@@ skipping 25 matching lines @@
     SkString coords2D("coords2D");
     if (0 != index) {
         coords2D.appendf("_%i", index);
     }
     this->codeAppendf("\tvec2 %s = %s.xy / %s.z;",
                       coords2D.c_str(), coords[index].c_str(), coords[index].c_str());
     return coords2D;
 }
 
 const char* GrGLSLFragmentShaderBuilder::fragmentPosition() {
-    fHasReadFragmentPosition = true;
+    SkDEBUGCODE(fUsedBuiltInState |= GrProcessor::kFragmentPosition_BuiltInState;)
 
     const GrGLSLCaps* glslCaps = fProgramBuilder->glslCaps();
     // We only declare "gl_FragCoord" when we're in the case where we want to use layout qualifiers
     // to reverse y. Otherwise it isn't necessary and whether the "in" qualifier appears in the
     // declaration varies in earlier GLSL specs. So it is simpler to omit it.
     if (fTopLeftFragPosRead) {
         fSetupFragPosition = true;
         return "gl_FragCoord";
     } else if (const char* extension = glslCaps->fragCoordConventionsExtensionString()) {
         if (!fSetupFragPosition) {
@@ skipping 68 matching lines @@
         // Redeclare gl_SampleMask with layout(override_coverage) if we haven't already.
         fOutputs.push_back().set(kInt_GrSLType, GrShaderVar::kOut_TypeModifier,
                                  "gl_SampleMask", 1, kHigh_GrSLPrecision,
                                  "override_coverage");
     }
     this->codeAppendf("gl_SampleMask[0] = %s;", mask);
     fHasInitializedSampleMask = true;
 }
 
 const char* GrGLSLFragmentShaderBuilder::dstColor() {
-    fHasReadDstColor = true;
+    SkDEBUGCODE(fHasReadDstColor = true;)
 
     const char* override = fProgramBuilder->primitiveProcessor().getDestColorOverride();
     if (override != nullptr) {
         return override;
     }
 
     const GrGLSLCaps* glslCaps = fProgramBuilder->glslCaps();
     if (glslCaps->fbFetchSupport()) {
         this->addFeature(1 << kFramebufferFetch_GLSLPrivateFeature,
                          glslCaps->fbFetchExtensionString());
@@ skipping 91 matching lines @@
 }
 
 void GrGLSLFragmentShaderBuilder::onAfterChildProcEmitCode() {
     SkASSERT(fSubstageIndices.count() >= 2);
     fSubstageIndices.pop_back();
     fSubstageIndices.back()++;
     int removeAt = fMangleString.findLastOf('_');
     fMangleString.remove(removeAt, fMangleString.size() - removeAt);
 }