added basic dataflow analysis to skslc

src/gpu/effects/GrBitmapTextGeoProc.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrBitmapTextGeoProc.h"
 #include "GrInvariantOutput.h"
 #include "GrTexture.h"
@@ skipping 45 matching lines @@
         // emit transforms
         this->emitTransforms(vertBuilder,
                              varyingHandler,
                              uniformHandler,
                              gpArgs->fPositionVar,
                              cte.inPosition()->fName,
                              cte.localMatrix(),
                              args.fFPCoordTransformHandler);
 
         if (cte.maskFormat() == kARGB_GrMaskFormat) {
-            fragBuilder->codeAppendf("%s = ", args.fOutputColor);
-            fragBuilder->appendTextureLookupAndModulate(args.fOutputColor,
-                                                        args.fTexSamplers[0],
-                                                        v.fsIn(),
-                                                        kVec2f_GrSLType);
-            fragBuilder->codeAppend(";");
-            fragBuilder->codeAppendf("%s = vec4(1);", args.fOutputCoverage);
+            if (!cte.colorIgnored()) {
+                fragBuilder->codeAppendf("%s = ", args.fOutputColor);
+                fragBuilder->appendTextureLookupAndModulate(args.fOutputColor,
+                                                            args.fTexSamplers[0],
+                                                            v.fsIn(),
+                                                            kVec2f_GrSLType);
+                fragBuilder->codeAppend(";");
+                fragBuilder->codeAppendf("%s = vec4(1);", args.fOutputCoverage);
+            }
         } else {
             fragBuilder->codeAppendf("%s = ", args.fOutputCoverage);
             fragBuilder->appendTextureLookup(args.fTexSamplers[0], v.fsIn(), kVec2f_GrSLType);
             fragBuilder->codeAppend(";");
             if (cte.maskFormat() == kA565_GrMaskFormat) {
                 // set alpha to be max of rgb coverage
                 fragBuilder->codeAppendf("%s.a = max(max(%s.r, %s.g), %s.b);",
                                          args.fOutputCoverage, args.fOutputCoverage,
                                          args.fOutputCoverage, args.fOutputCoverage);
             }
@@ skipping 99 matching lines @@
             break;
         case 2:
             format = kARGB_GrMaskFormat;
             break;
     }
 
     return GrBitmapTextGeoProc::Make(GrRandomColor(d->fRandom), d->fTextures[texIdx], params,
                                      format, GrTest::TestMatrix(d->fRandom),
                                      d->fRandom->nextBool());
 }