Fix case where GrGLEffectMatrix gives back a dangling ptr for the coords var name.

src/gpu/effects/GrSimpleTextureEffect.cpp

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "GrSimpleTextureEffect.h"
 #include "gl/GrGLEffect.h"
 #include "gl/GrGLEffectMatrix.h"
@@ skipping 13 matching lines @@
         }
     }
 
     virtual void emitCode(GrGLShaderBuilder* builder,
                           const GrDrawEffect& drawEffect,
                           EffectKey key,
                           const char* outputColor,
                           const char* inputColor,
                           const TextureSamplerArray& samplers) SK_OVERRIDE {
         const GrSimpleTextureEffect& ste = drawEffect.castEffect<GrSimpleTextureEffect>();
-        const char* fsCoordName;
+        SkString fsCoordName;
         GrSLType fsCoordSLType;
         if (GrEffect::kCustom_CoordsType == ste.coordsType()) {
             SkASSERT(ste.getMatrix().isIdentity());
             SkASSERT(1 == ste.numVertexAttribs());
             fsCoordSLType = kVec2f_GrSLType;
             const char* vsVaryingName;
-            builder->addVarying(kVec2f_GrSLType, "textureCoords", &vsVaryingName, &fsCoordName);
+            const char* fsVaryingNamePtr;

[bsalomon, 2013/08/28 14:03:18]

This is a bit ugly but I'd like to have a follow up change that makes addVarying
take a SkString* so we can just pass &fsCoordName.

[robertphillips, 2013/08/28 14:48:44]

SGTM - should vsVaryingName be changed at the same time too?

[bsalomon, 2013/08/28 15:39:59]

yup

+            builder->addVarying(kVec2f_GrSLType, "textureCoords", &vsVaryingName, &fsVaryingNamePtr);
+            fsCoordName = fsVaryingNamePtr;
             const char* attrName =
                 builder->getEffectAttributeName(drawEffect.getVertexAttribIndices()[0])->c_str();
             builder->vsCodeAppendf("\t%s = %s;\n", vsVaryingName, attrName);
         } else {
             fsCoordSLType = fEffectMatrix.get()->emitCode(builder, key, &fsCoordName);
         }
         builder->fsCodeAppendf("\t%s = ", outputColor);
         builder->appendTextureLookupAndModulate(GrGLShaderBuilder::kFragment_ShaderType,
                                                 inputColor,
                                                 samplers[0],
-                                                fsCoordName,
+                                                fsCoordName.c_str(),
                                                 fsCoordSLType);
         builder->fsCodeAppend(";\n");
     }
 
     static inline EffectKey GenKey(const GrDrawEffect& drawEffect, const GrGLCaps&) {
         const GrSimpleTextureEffect& ste = drawEffect.castEffect<GrSimpleTextureEffect>();
         if (GrEffect::kCustom_CoordsType == ste.coordsType()) {
             return 1 << GrGLEffectMatrix::kKeyBits;
         } else {
             return GrGLEffectMatrix::GenKey(ste.getMatrix(),
@@ skipping 57 matching lines @@
     };
     CoordsType coordsType = kCoordsTypes[random->nextULessThan(GR_ARRAY_COUNT(kCoordsTypes))];
 
     if (kCustom_CoordsType == coordsType) {
         return GrSimpleTextureEffect::CreateWithCustomCoords(textures[texIdx], params);
     } else {
         const SkMatrix& matrix = GrEffectUnitTest::TestMatrix(random);
         return GrSimpleTextureEffect::Create(textures[texIdx], matrix);
     }
 }