Remove willReadDst from GrFragmentProcessor.

Since only XP's can read dst now, there is no reason to have this query on GrFP.
This also triggered a chain reaction of cleaning up/removing unnecessary code
elsewhere.

BUG=skia:

Review URL: https://codereview.chromium.org/851143003

13 files changed, 20 insertions, 93 deletions

diff --git a/src/gpu/GrDrawState.cpp b/src/gpu/GrDrawState.cpp
index 36042e19ab..4ec39e7005 100644
--- a/src/gpu/GrDrawState.cpp
+++ b/src/gpu/GrDrawState.cpp
@@ -147,11 +147,8 @@ bool GrDrawState::canUseFracCoveragePrimProc(GrColor color, const GrDrawTargetCa
 
 //////////////////////////////////////////////////////////////////////////////s
 
-bool GrDrawState::willEffectReadDstColor(const GrPrimitiveProcessor* pp) const {
-    this->calcColorInvariantOutput(pp);
-    this->calcCoverageInvariantOutput(pp);
-
-    return fXPFactory->willReadDst(fColorProcInfo, fCoverageProcInfo);
+bool GrDrawState::willEffectReadDstColor() const {
+    return fXPFactory->willReadDst();
 }
 
 void GrDrawState::AutoRestoreEffects::set(GrDrawState* ds) {
diff --git a/src/gpu/GrDrawState.h b/src/gpu/GrDrawState.h
index ce29e6ca68..c02429f965 100644
--- a/src/gpu/GrDrawState.h
+++ b/src/gpu/GrDrawState.h
@@ -108,10 +108,10 @@ public:
     const GrFragmentStage& getCoverageStage(int idx) const { return fCoverageStages[idx]; }
 
     /**
-     * Checks whether any of the effects will read the dst pixel color.
-     * TODO remove when we have an XP
+     * Checks whether the xp will read the dst pixel color.
+     * TODO: remove when we have dstCpy contained inside of GrXP
      */
-    bool willEffectReadDstColor(const GrPrimitiveProcessor*) const;
+    bool willEffectReadDstColor() const;
 
     /**
      * The xfer processor factory.
diff --git a/src/gpu/GrDrawTarget.cpp b/src/gpu/GrDrawTarget.cpp
index 5faf00f843..f14515462a 100644
--- a/src/gpu/GrDrawTarget.cpp
+++ b/src/gpu/GrDrawTarget.cpp
@@ -383,10 +383,9 @@ bool GrDrawTarget::checkDraw(const GrDrawState& drawState,
 }
 
 bool GrDrawTarget::setupDstReadIfNecessary(GrDrawState* ds,
-                                           const GrPrimitiveProcessor* primProc,
                                            GrDeviceCoordTexture* dstCopy,
                                            const SkRect* drawBounds) {
-    if (this->caps()->dstReadInShaderSupport() || !ds->willEffectReadDstColor(primProc)) {
+    if (this->caps()->dstReadInShaderSupport() || !ds->willEffectReadDstColor()) {
         return true;
     }
     SkIRect copyRect;
@@ -470,7 +469,7 @@ void GrDrawTarget::drawIndexed(GrDrawState* ds,
 
         // TODO: We should continue with incorrect blending.
         GrDeviceCoordTexture dstCopy;
-        if (!this->setupDstReadIfNecessary(ds, gp, &dstCopy, devBounds)) {
+        if (!this->setupDstReadIfNecessary(ds, &dstCopy, devBounds)) {
             return;
         }
         this->setDrawBuffers(&info, gp->getVertexStride());
@@ -513,7 +512,7 @@ void GrDrawTarget::drawNonIndexed(GrDrawState* ds,
 
         // TODO: We should continue with incorrect blending.
         GrDeviceCoordTexture dstCopy;
-        if (!this->setupDstReadIfNecessary(ds, gp, &dstCopy, devBounds)) {
+        if (!this->setupDstReadIfNecessary(ds, &dstCopy, devBounds)) {
             return;
         }
 
@@ -611,7 +610,7 @@ void GrDrawTarget::drawPath(GrDrawState* ds,
                                             &stencilSettings);
 
     GrDeviceCoordTexture dstCopy;
-    if (!this->setupDstReadIfNecessary(ds, pathProc, &dstCopy, &devBounds)) {
+    if (!this->setupDstReadIfNecessary(ds, &dstCopy, &devBounds)) {
         return;
     }
 
@@ -655,7 +654,7 @@ void GrDrawTarget::drawPaths(GrDrawState* ds,
     // point, because any context that supports NV_path_rendering will also
     // support NV_blend_equation_advanced.
     GrDeviceCoordTexture dstCopy;
-    if (!this->setupDstReadIfNecessary(ds, pathProc, &dstCopy, NULL)) {
+    if (!this->setupDstReadIfNecessary(ds, &dstCopy, NULL)) {
         return;
     }
 
@@ -768,7 +767,7 @@ void GrDrawTarget::drawIndexedInstances(GrDrawState* ds,
 
     // TODO: We should continue with incorrect blending.
     GrDeviceCoordTexture dstCopy;
-    if (!this->setupDstReadIfNecessary(ds, gp, &dstCopy, devBounds)) {
+    if (!this->setupDstReadIfNecessary(ds, &dstCopy, devBounds)) {
         return;
     }
 
diff --git a/src/gpu/GrDrawTarget.h b/src/gpu/GrDrawTarget.h
index 0e211ba85d..6628e37228 100644
--- a/src/gpu/GrDrawTarget.h
+++ b/src/gpu/GrDrawTarget.h
@@ -661,7 +661,6 @@ protected:
     // but couldn't be made. Otherwise, returns true.  This method needs to be protected because it
     // needs to be accessed by GLPrograms to setup a correct drawstate
     bool setupDstReadIfNecessary(GrDrawState*,
-                                 const GrPrimitiveProcessor*,
                                  GrDeviceCoordTexture* dstCopy,
                                  const SkRect* drawBounds);
 
diff --git a/src/gpu/GrOptDrawState.cpp b/src/gpu/GrOptDrawState.cpp
index 742ffade12..bc1ce7dc93 100644
--- a/src/gpu/GrOptDrawState.cpp
+++ b/src/gpu/GrOptDrawState.cpp
@@ -89,6 +89,8 @@ GrOptDrawState::GrOptDrawState(const GrDrawState& drawState,
     this->adjustProgramFromOptimizations(drawState, optFlags, colorPOI, coveragePOI,
                                          &firstColorStageIdx, &firstCoverageStageIdx);
 
+    fDescInfo.fReadsDst = fXferProcessor->willReadDstColor();
+
     bool usesLocalCoords = false;
 
     // Copy Stages from DS to ODS
@@ -124,31 +126,22 @@ void GrOptDrawState::adjustProgramFromOptimizations(const GrDrawState& ds,
                                                     const GrProcOptInfo& coveragePOI,
                                                     int* firstColorStageIdx,
                                                     int* firstCoverageStageIdx) {
-    fDescInfo.fReadsDst = false;
     fDescInfo.fReadsFragPosition = false;
 
     if ((flags & GrXferProcessor::kIgnoreColor_OptFlag) ||
         (flags & GrXferProcessor::kOverrideColor_OptFlag)) {
         *firstColorStageIdx = ds.numColorStages();
     } else {
-        fDescInfo.fReadsDst = colorPOI.readsDst();
         fDescInfo.fReadsFragPosition = colorPOI.readsFragPosition();
     }
 
     if (flags & GrXferProcessor::kIgnoreCoverage_OptFlag) {
         *firstCoverageStageIdx = ds.numCoverageStages();
     } else {
-        if (coveragePOI.readsDst()) {
-            fDescInfo.fReadsDst = true;
-        }
         if (coveragePOI.readsFragPosition()) {
             fDescInfo.fReadsFragPosition = true;
         }
     }
-
-    if (fXferProcessor->willReadDstColor()) {
-        fDescInfo.fReadsDst = true;
-    }
 }
 
 void GrOptDrawState::finalize(GrGpu* gpu) {
diff --git a/src/gpu/GrProcOptInfo.cpp b/src/gpu/GrProcOptInfo.cpp
index 274c5305de..a350ef783d 100644
--- a/src/gpu/GrProcOptInfo.cpp
+++ b/src/gpu/GrProcOptInfo.cpp
@@ -48,7 +48,6 @@ void GrProcOptInfo::internalCalc(const GrFragmentStage* stages,
     fFirstEffectStageIndex = 0;
     fInputColorIsUsed = true;
     fInputColor = fInOut.color();
-    fReadsDst = false;
     fReadsFragPosition = initWillReadFragmentPosition;
 
     for (int i = 0; i < stageCount; ++i) {
@@ -60,12 +59,8 @@ void GrProcOptInfo::internalCalc(const GrFragmentStage* stages,
             fFirstEffectStageIndex = i;
             fInputColorIsUsed = false;
             // Reset these since we don't care if previous stages read these values
-            fReadsDst = false;
             fReadsFragPosition = initWillReadFragmentPosition;
         }
-        if (processor->willReadDstColor()) {
-            fReadsDst = true;
-        }
         if (processor->willReadFragmentPosition()) {
             fReadsFragPosition = true;
         }
@@ -77,7 +72,6 @@ void GrProcOptInfo::internalCalc(const GrFragmentStage* stages,
             // zero stages that don't multiply the inputColor.
             fInOut.resetNonMulStageFound();
             // Reset these since we don't care if previous stages read these values
-            fReadsDst = false;
             fReadsFragPosition = initWillReadFragmentPosition;
         }
     }
diff --git a/src/gpu/GrProcOptInfo.h b/src/gpu/GrProcOptInfo.h
index 43d6c558f1..75d88c64e2 100644
--- a/src/gpu/GrProcOptInfo.h
+++ b/src/gpu/GrProcOptInfo.h
@@ -28,7 +28,6 @@ public:
         , fFirstEffectStageIndex(0)
         , fInputColorIsUsed(true)
         , fInputColor(0)
-        , fReadsDst(false)
         , fReadsFragPosition(false) {}
 
     void calcWithInitialValues(const GrFragmentStage*, int stageCount, GrColor startColor,
@@ -75,11 +74,6 @@ public:
     GrColor inputColorToEffectiveStage() const { return fInputColor; }
 
     /**
-     * Returns true if any of the stages preserved by GrProcOptInfo read the dst color.
-     */
-    bool readsDst() const { return fReadsDst; }
-
-    /**
      * Returns true if any of the stages preserved by GrProcOptInfo read the frag position.
      */
     bool readsFragPosition() const { return fReadsFragPosition; }
@@ -91,7 +85,6 @@ private:
     int fFirstEffectStageIndex;
     bool fInputColorIsUsed;
     GrColor fInputColor;
-    bool fReadsDst;
     bool fReadsFragPosition;
 };
 
diff --git a/src/gpu/effects/GrCoverageSetOpXP.cpp b/src/gpu/effects/GrCoverageSetOpXP.cpp
index bb87616e74..fe286f6bf5 100644
--- a/src/gpu/effects/GrCoverageSetOpXP.cpp
+++ b/src/gpu/effects/GrCoverageSetOpXP.cpp
@@ -195,22 +195,13 @@ void GrCoverageSetOpXPFactory::getInvariantOutput(const GrProcOptInfo& colorPOI,
             output->fBlendedColorFlags = 0;
         }
 
-        if (coveragePOI.readsDst()) {
-            output->fWillBlendWithDst = true;
-        } else {
-            output->fWillBlendWithDst = false;
-        }
+        output->fWillBlendWithDst = false;
     } else {
         output->fBlendedColorFlags = 0;
         output->fWillBlendWithDst = true;
     }
 }
 
-bool GrCoverageSetOpXPFactory::willReadDst(const GrProcOptInfo& colorPOI,
-                                           const GrProcOptInfo& coveragePOI) const {
-    return coveragePOI.readsDst();
-}
-
 GR_DEFINE_XP_FACTORY_TEST(GrCoverageSetOpXPFactory);
 
 GrXPFactory* GrCoverageSetOpXPFactory::TestCreate(SkRandom* random,
diff --git a/src/gpu/effects/GrCoverageSetOpXP.h b/src/gpu/effects/GrCoverageSetOpXP.h
index 289b5cf307..a144f975b7 100644
--- a/src/gpu/effects/GrCoverageSetOpXP.h
+++ b/src/gpu/effects/GrCoverageSetOpXP.h
@@ -83,8 +83,7 @@ public:
     void getInvariantOutput(const GrProcOptInfo& colorPOI, const GrProcOptInfo& coveragePOI,
                             GrXPFactory::InvariantOutput*) const SK_OVERRIDE;
 
-    bool willReadDst(const GrProcOptInfo& colorPOI,
-                     const GrProcOptInfo& coveragePOI) const SK_OVERRIDE;
+    bool willReadDst() const SK_OVERRIDE { return false; }
 
 private:
     GrCoverageSetOpXPFactory(SkRegion::Op regionOp, bool invertCoverage);
diff --git a/src/gpu/effects/GrCustomXfermodePriv.h b/src/gpu/effects/GrCustomXfermodePriv.h
index 48ad7842f5..45a9d3005d 100644
--- a/src/gpu/effects/GrCustomXfermodePriv.h
+++ b/src/gpu/effects/GrCustomXfermodePriv.h
@@ -126,10 +126,7 @@ public:
     void getInvariantOutput(const GrProcOptInfo& colorPOI, const GrProcOptInfo& coveragePOI,
                             GrXPFactory::InvariantOutput*) const SK_OVERRIDE;
 
-    bool willReadDst(const GrProcOptInfo& colorPOI,
-                     const GrProcOptInfo& coveragePOI) const SK_OVERRIDE {
-        return true;
-    }
+    bool willReadDst() const SK_OVERRIDE { return true; }
 
 private:
     bool onIsEqual(const GrXPFactory& xpfBase) const SK_OVERRIDE {
diff --git a/src/gpu/effects/GrDisableColorXP.h b/src/gpu/effects/GrDisableColorXP.h
index b0de66bf43..d62c3201dd 100644
--- a/src/gpu/effects/GrDisableColorXP.h
+++ b/src/gpu/effects/GrDisableColorXP.h
@@ -81,10 +81,7 @@ public:
         output->fWillBlendWithDst = 0;
     }
 
-    bool willReadDst(const GrProcOptInfo& colorPOI,
-                     const GrProcOptInfo& coveragePOI) const SK_OVERRIDE {
-        return false;
-    }
+    bool willReadDst() const SK_OVERRIDE { return false; }
 
 private:
     GrDisableColorXPFactory();
diff --git a/src/gpu/effects/GrPorterDuffXferProcessor.cpp b/src/gpu/effects/GrPorterDuffXferProcessor.cpp
index aecf685e62..5038aa333f 100644
--- a/src/gpu/effects/GrPorterDuffXferProcessor.cpp
+++ b/src/gpu/effects/GrPorterDuffXferProcessor.cpp
@@ -72,14 +72,8 @@ public:
                 fsBuilder->codeAppendf("%s = %s;", args.fOutputPrimary, args.fInputCoverage);
                 break;
             case GrPorterDuffXferProcessor::kModulate_PrimaryOutputType:
-            case GrPorterDuffXferProcessor::kCombineWithDst_PrimaryOutputType:
                 fsBuilder->codeAppendf("%s = %s * %s;", args.fOutputPrimary, args.fInputColor,
                                        args.fInputCoverage);
-                if (GrPorterDuffXferProcessor::kCombineWithDst_PrimaryOutputType ==
-                    xp.primaryOutputType()){
-                    fsBuilder->codeAppendf("%s += (vec4(1.0) - %s) * %s;", args.fOutputPrimary,
-                                           args.fInputCoverage, fsBuilder->dstColor());
-                }
                 break;
             default:
                 SkFAIL("Unexpected Primary Output");
@@ -144,14 +138,13 @@ GrPorterDuffXferProcessor::getOptimizations(const GrProcOptInfo& colorPOI,
                                                   coveragePOI,
                                                   doesStencilWrite);
     }
-    this->calcOutputTypes(optFlags, caps, coveragePOI.isSolidWhite(),
-                          colorPOI.readsDst() || coveragePOI.readsDst());
+    this->calcOutputTypes(optFlags, caps, coveragePOI.isSolidWhite());
     return optFlags;
 }
 
 void GrPorterDuffXferProcessor::calcOutputTypes(GrXferProcessor::OptFlags optFlags,
                                                 const GrDrawTargetCaps& caps,
-                                                bool hasSolidCoverage, bool readsDst) {
+                                                bool hasSolidCoverage) {
     if (optFlags & kIgnoreColor_OptFlag) {
         if (optFlags & kIgnoreCoverage_OptFlag) {
             fPrimaryOutputType = kNone_PrimaryOutputType;
@@ -184,10 +177,6 @@ void GrPorterDuffXferProcessor::calcOutputTypes(GrXferProcessor::OptFlags optFla
                 fSecondaryOutputType = kCoverageISC_SecondaryOutputType;
                 fDstBlend = (GrBlendCoeff)GrGpu::kIS2C_GrBlendCoeff;
             }
-        } else if (readsDst &&
-                   kOne_GrBlendCoeff == fSrcBlend &&
-                   kZero_GrBlendCoeff == fDstBlend) {
-            fPrimaryOutputType = kCombineWithDst_PrimaryOutputType;
         }
     }
 }
@@ -419,13 +408,6 @@ bool GrPorterDuffXPFactory::canApplyCoverage(const GrProcOptInfo& colorPOI,
         return true;
     }
 
-    // TODO: once all SkXferEffects are XP's then we will never reads dst here since only XP's
-    // will readDst and PD XP's don't read dst.
-    if ((colorPOI.readsDst() || coveragePOI.readsDst()) &&
-        kOne_GrBlendCoeff == fSrcCoeff && kZero_GrBlendCoeff == fDstCoeff) {
-        return true;
-    }
-
     return false;
 }
 
@@ -499,20 +481,9 @@ void GrPorterDuffXPFactory::getInvariantOutput(const GrProcOptInfo& colorPOI,
             break;
     }
 
-    // TODO: once all SkXferEffects are XP's then we will never reads dst here since only XP's
-    // will readDst and PD XP's don't read dst.
-    if (colorPOI.readsDst() || coveragePOI.readsDst()) {
-        output->fWillBlendWithDst = true;
-        return;
-    }
     output->fWillBlendWithDst = false;
 }
 
-bool GrPorterDuffXPFactory::willReadDst(const GrProcOptInfo& colorPOI,
-                                        const GrProcOptInfo& coveragePOI) const {
-    return colorPOI.readsDst() || coveragePOI.readsDst();
-}
-
 GR_DEFINE_XP_FACTORY_TEST(GrPorterDuffXPFactory);
 
 GrXPFactory* GrPorterDuffXPFactory::TestCreate(SkRandom* random,
diff --git a/src/gpu/gl/builders/GrGLProgramBuilder.cpp b/src/gpu/gl/builders/GrGLProgramBuilder.cpp
index 8ec0d2ddbe..c88efac9f0 100644
--- a/src/gpu/gl/builders/GrGLProgramBuilder.cpp
+++ b/src/gpu/gl/builders/GrGLProgramBuilder.cpp
@@ -359,14 +359,11 @@ void GrGLProgramBuilder::verify(const GrPrimitiveProcessor& gp) {
 }
 
 void GrGLProgramBuilder::verify(const GrXferProcessor& xp) {
-    // TODO: Once will readDst is only xp enable this assert and remove it from the
-    // FragmentProcessor verify()
-    //SkASSERT(fFS.hasReadDstColor() == xp.willReadDstColor());
+    SkASSERT(fFS.hasReadDstColor() == xp.willReadDstColor());
 }
 
 void GrGLProgramBuilder::verify(const GrFragmentProcessor& fp) {
     SkASSERT(fFS.hasReadFragmentPosition() == fp.willReadFragmentPosition());
-    SkASSERT(fFS.hasReadDstColor() == fp.willReadDstColor());
 }
 
 template <class Proc>