enforce 16byte alignment in shader contexts

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1759653004

Review URL: https://codereview.chromium.org/1759653004

15 files changed, 51 insertions, 43 deletions

diff --git a/src/core/SkBitmapProcShader.cpp b/src/core/SkBitmapProcShader.cpp
index 895922c6b8..6c87ebeda4 100644
--- a/src/core/SkBitmapProcShader.cpp
+++ b/src/core/SkBitmapProcShader.cpp
@@ -120,7 +120,7 @@ private:
 size_t SkBitmapProcShader::ContextSize(const ContextRec& rec) {
     // The SkBitmapProcState is stored outside of the context object, with the context holding
     // a pointer to it.
-    return sizeof(BitmapProcShaderContext) + sizeof(SkBitmapProcState);
+    return SkAlign16(sizeof(BitmapProcShaderContext) + sizeof(SkBitmapProcState));
 }
 
 SkShader::Context* SkBitmapProcShader::MakeContext(const SkShader& shader,
diff --git a/src/core/SkBitmapProcShader.h b/src/core/SkBitmapProcShader.h
index 9f4c16202c..ebd9f3f8fb 100644
--- a/src/core/SkBitmapProcShader.h
+++ b/src/core/SkBitmapProcShader.h
@@ -21,7 +21,7 @@ public:
 
     bool isOpaque() const override;
 
-    size_t contextSize(const ContextRec& rec) const override { return ContextSize(rec); }
+    size_t onContextSize(const ContextRec& rec) const override { return ContextSize(rec); }
 
     SK_TO_STRING_OVERRIDE()
     SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkBitmapProcShader)
diff --git a/src/core/SkBlitter.cpp b/src/core/SkBlitter.cpp
index c7c903dc6b..bb5cfb72e3 100644
--- a/src/core/SkBlitter.cpp
+++ b/src/core/SkBlitter.cpp
@@ -592,7 +592,7 @@ public:
         SkSafeUnref(fProxy);
     }
 
-    size_t contextSize(const ContextRec& rec) const override {
+    size_t onContextSize(const ContextRec& rec) const override {
         size_t size = sizeof(Sk3DShaderContext);
         if (fProxy) {
             size += fProxy->contextSize(rec);
diff --git a/src/core/SkColorFilterShader.cpp b/src/core/SkColorFilterShader.cpp
index 7b421e9b6d..c856f19150 100644
--- a/src/core/SkColorFilterShader.cpp
+++ b/src/core/SkColorFilterShader.cpp
@@ -62,8 +62,8 @@ SkShader::Context* SkColorFilterShader::onCreateContext(const ContextRec& rec,
     return new (storage) FilterShaderContext(*this, shaderContext, rec);
 }
 
-size_t SkColorFilterShader::contextSize(const ContextRec& rec) const {
-    return sizeof(FilterShaderContext) + fShader->contextSize(rec);
+size_t SkColorFilterShader::onContextSize(const ContextRec& rec) const {
+    return SkAlign16(sizeof(FilterShaderContext)) + fShader->contextSize(rec);
 }
 
 SkColorFilterShader::FilterShaderContext::FilterShaderContext(
diff --git a/src/core/SkColorFilterShader.h b/src/core/SkColorFilterShader.h
index 60c45954dc..0f41a43c49 100644
--- a/src/core/SkColorFilterShader.h
+++ b/src/core/SkColorFilterShader.h
@@ -14,9 +14,7 @@
 class SkColorFilterShader : public SkShader {
 public:
     SkColorFilterShader(SkShader* shader, SkColorFilter* filter);
-    
-    size_t contextSize(const ContextRec&) const override;
-    
+
 #if SK_SUPPORT_GPU
     const GrFragmentProcessor* asFragmentProcessor(GrContext*,
                                                    const SkMatrix& viewM,
@@ -51,9 +49,9 @@ public:
     
 protected:
     void flatten(SkWriteBuffer&) const override;
+    size_t onContextSize(const ContextRec&) const override;
     Context* onCreateContext(const ContextRec&, void* storage) const override;
     
-    
 private:
     SkAutoTUnref<SkShader>      fShader;
     SkAutoTUnref<SkColorFilter> fFilter;
diff --git a/src/core/SkColorShader.h b/src/core/SkColorShader.h
index 6e4e42ad95..00a2bb61f0 100644
--- a/src/core/SkColorShader.h
+++ b/src/core/SkColorShader.h
@@ -26,10 +26,6 @@ public:
 
     bool isOpaque() const override;
 
-    size_t contextSize(const ContextRec&) const override {
-        return sizeof(ColorShaderContext);
-    }
-
     class ColorShaderContext : public SkShader::Context {
     public:
         ColorShaderContext(const SkColorShader& shader, const ContextRec&);
@@ -61,6 +57,9 @@ protected:
     SkColorShader(SkReadBuffer&);
     void flatten(SkWriteBuffer&) const override;
     Context* onCreateContext(const ContextRec&, void* storage) const override;
+    size_t onContextSize(const ContextRec&) const override {
+        return sizeof(ColorShaderContext);
+    }
     bool onAsLuminanceColor(SkColor* lum) const override {
         *lum = fColor;
         return true;
diff --git a/src/core/SkComposeShader.cpp b/src/core/SkComposeShader.cpp
index 46ff4019fc..e4ad6e9eda 100644
--- a/src/core/SkComposeShader.cpp
+++ b/src/core/SkComposeShader.cpp
@@ -30,8 +30,8 @@ SkComposeShader::~SkComposeShader() {
     fShaderA->unref();
 }
 
-size_t SkComposeShader::contextSize(const ContextRec& rec) const {
-    return sizeof(ComposeShaderContext)
+size_t SkComposeShader::onContextSize(const ContextRec& rec) const {
+    return SkAlign16(sizeof(ComposeShaderContext))
         + fShaderA->contextSize(rec)
         + fShaderB->contextSize(rec);
 }
@@ -76,7 +76,7 @@ template <typename T> void safe_call_destructor(T* obj) {
 }
 
 SkShader::Context* SkComposeShader::onCreateContext(const ContextRec& rec, void* storage) const {
-    char* aStorage = (char*) storage + sizeof(ComposeShaderContext);
+    char* aStorage = (char*) storage + SkAlign16(sizeof(ComposeShaderContext));
     char* bStorage = aStorage + fShaderA->contextSize(rec);
 
     // we preconcat our localMatrix (if any) with the device matrix
diff --git a/src/core/SkComposeShader.h b/src/core/SkComposeShader.h
index 6f6aa59525..9220a0de97 100644
--- a/src/core/SkComposeShader.h
+++ b/src/core/SkComposeShader.h
@@ -34,8 +34,6 @@ public:
     SkComposeShader(SkShader* sA, SkShader* sB, SkXfermode* mode = NULL);
     virtual ~SkComposeShader();
 
-    size_t contextSize(const ContextRec&) const override;
-
 #if SK_SUPPORT_GPU
     const GrFragmentProcessor*  asFragmentProcessor(GrContext*,
                                                     const SkMatrix& viewM,
@@ -77,6 +75,7 @@ public:
 protected:
     SkComposeShader(SkReadBuffer& );
     void flatten(SkWriteBuffer&) const override;
+    size_t onContextSize(const ContextRec&) const override;
     Context* onCreateContext(const ContextRec&, void*) const override;
 
 private:
diff --git a/src/core/SkDraw.cpp b/src/core/SkDraw.cpp
index cff4252579..e9b0677c33 100644
--- a/src/core/SkDraw.cpp
+++ b/src/core/SkDraw.cpp
@@ -1698,8 +1698,6 @@ class SkTriColorShader : public SkShader {
 public:
     SkTriColorShader() {}
 
-    size_t contextSize(const ContextRec&) const override;
-
     class TriColorShaderContext : public SkShader::Context {
     public:
         TriColorShaderContext(const SkTriColorShader& shader, const ContextRec&);
@@ -1722,6 +1720,7 @@ public:
     Factory getFactory() const override { sk_throw(); return nullptr; }
 
 protected:
+    size_t onContextSize(const ContextRec&) const override;
     Context* onCreateContext(const ContextRec& rec, void* storage) const override {
         return new (storage) TriColorShaderContext(*this, rec);
     }
@@ -1772,9 +1771,10 @@ SkTriColorShader::TriColorShaderContext::TriColorShaderContext(const SkTriColorS
 
 SkTriColorShader::TriColorShaderContext::~TriColorShaderContext() {}
 
-size_t SkTriColorShader::contextSize(const ContextRec&) const {
-    return sizeof(TriColorShaderContext);
+size_t SkTriColorShader::onContextSize(const ContextRec&) const {
+    return SkAlign16(sizeof(TriColorShaderContext));
 }
+
 void SkTriColorShader::TriColorShaderContext::shadeSpan(int x, int y, SkPMColor dstC[], int count) {
     const int alphaScale = Sk255To256(this->getPaintAlpha());
 
diff --git a/src/core/SkEmptyShader.h b/src/core/SkEmptyShader.h
index c1713d1a2e..42b61c52fe 100644
--- a/src/core/SkEmptyShader.h
+++ b/src/core/SkEmptyShader.h
@@ -20,16 +20,16 @@ class SK_API SkEmptyShader : public SkShader {
 public:
     SkEmptyShader() {}
 
-    size_t contextSize(const ContextRec&) const override {
-        // Even though createContext returns nullptr we have to return a value of at least
-        // sizeof(SkShader::Context) to satisfy SkSmallAllocator.
-        return sizeof(SkShader::Context);
-    }
-
     SK_TO_STRING_OVERRIDE()
     SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkEmptyShader)
 
 protected:
+    size_t onContextSize(const ContextRec&) const override {
+        // Even though createContext returns nullptr we have to return a value of at least
+        // sizeof(SkShader::Context) to satisfy SkSmallAllocator.
+        return SkAlign16(sizeof(SkShader::Context));
+    }
+
     SkShader::Context* onCreateContext(const ContextRec&, void*) const override {
         return nullptr;
     }
diff --git a/src/core/SkLightingShader.cpp b/src/core/SkLightingShader.cpp
index c8a5a2b737..02f75f3516 100644
--- a/src/core/SkLightingShader.cpp
+++ b/src/core/SkLightingShader.cpp
@@ -79,8 +79,6 @@ public:
                                                    SkFilterQuality) const override;
 #endif
 
-    size_t contextSize(const ContextRec&) const override;
-
     class LightingShaderContext : public SkShader::Context {
     public:
         // The context takes ownership of the states. It will call their destructors
@@ -106,6 +104,7 @@ public:
 
 protected:
     void flatten(SkWriteBuffer&) const override;
+    size_t onContextSize(const ContextRec&) const override;
     Context* onCreateContext(const ContextRec&, void*) const override;
     bool computeNormTotalInverse(const ContextRec& rec, SkMatrix* normTotalInverse) const;
 
@@ -416,10 +415,6 @@ bool SkLightingShaderImpl::isOpaque() const {
     return fDiffuseMap.isOpaque();
 }
 
-size_t SkLightingShaderImpl::contextSize(const ContextRec&) const {
-    return 2 * sizeof(SkBitmapProcState) + sizeof(LightingShaderContext);
-}
-
 SkLightingShaderImpl::LightingShaderContext::LightingShaderContext(const SkLightingShaderImpl& shader,
                                                                    const ContextRec& rec,
                                                                    SkBitmapProcState* diffuseState,
@@ -655,6 +650,10 @@ bool SkLightingShaderImpl::computeNormTotalInverse(const ContextRec& rec,
     return m->invert(normTotalInverse);
 }
 
+size_t SkLightingShaderImpl::onContextSize(const ContextRec&) const {
+    return 2 * sizeof(SkBitmapProcState) + sizeof(LightingShaderContext);
+}
+
 SkShader::Context* SkLightingShaderImpl::onCreateContext(const ContextRec& rec,
                                                          void* storage) const {
 
diff --git a/src/core/SkLocalMatrixShader.h b/src/core/SkLocalMatrixShader.h
index d897d49ded..8edea40d05 100644
--- a/src/core/SkLocalMatrixShader.h
+++ b/src/core/SkLocalMatrixShader.h
@@ -19,10 +19,6 @@ public:
     , fProxyShader(SkRef(proxy))
     {}
 
-    size_t contextSize(const ContextRec& rec) const override {
-        return fProxyShader->contextSize(rec);
-    }
-
     GradientType asAGradient(GradientInfo* info) const override {
         return fProxyShader->asAGradient(info);
     }
@@ -53,6 +49,10 @@ protected:
     void flatten(SkWriteBuffer&) const override;
     Context* onCreateContext(const ContextRec&, void*) const override;
 
+    size_t onContextSize(const ContextRec& rec) const override {
+        return fProxyShader->contextSize(rec);
+    }
+
     bool onIsABitmap(SkBitmap* bitmap, SkMatrix* matrix, TileMode* mode) const override {
         return fProxyShader->isABitmap(bitmap, matrix, mode);
     }
diff --git a/src/core/SkPictureShader.cpp b/src/core/SkPictureShader.cpp
index f1addadd20..630b1bf8e1 100644
--- a/src/core/SkPictureShader.cpp
+++ b/src/core/SkPictureShader.cpp
@@ -241,8 +241,8 @@ SkShader* SkPictureShader::refBitmapShader(const SkMatrix& viewMatrix, const SkM
     return tileShader.detach();
 }
 
-size_t SkPictureShader::contextSize(const ContextRec&) const {
-    return sizeof(PictureShaderContext);
+size_t SkPictureShader::onContextSize(const ContextRec&) const {
+    return SkAlign16(sizeof(PictureShaderContext));
 }
 
 SkShader::Context* SkPictureShader::onCreateContext(const ContextRec& rec, void* storage) const {
diff --git a/src/core/SkPictureShader.h b/src/core/SkPictureShader.h
index c7a6a44fe0..8cccd251d5 100644
--- a/src/core/SkPictureShader.h
+++ b/src/core/SkPictureShader.h
@@ -25,8 +25,6 @@ public:
     static SkShader* Create(const SkPicture*, TileMode, TileMode, const SkMatrix*,
                                    const SkRect*);
 
-    size_t contextSize(const ContextRec&) const override;
-
     SK_TO_STRING_OVERRIDE()
     SK_DECLARE_PUBLIC_FLATTENABLE_DESERIALIZATION_PROCS(SkPictureShader)
 
@@ -40,6 +38,7 @@ public:
 protected:
     SkPictureShader(SkReadBuffer&);
     void flatten(SkWriteBuffer&) const override;
+    size_t onContextSize(const ContextRec&) const override;
     Context* onCreateContext(const ContextRec&, void* storage) const override;
 
 private:
diff --git a/src/core/SkShader.cpp b/src/core/SkShader.cpp
index e36df5b5af..fd5fb00b88 100644
--- a/src/core/SkShader.cpp
+++ b/src/core/SkShader.cpp
@@ -86,6 +86,10 @@ bool SkShader::asLuminanceColor(SkColor* colorPtr) const {
 }
 
 SkShader::Context* SkShader::createContext(const ContextRec& rec, void* storage) const {
+    // Currently we require each context to be allocated on 16byte boundary as some of our
+    // subclasses need that. Hence we check the ptr here.
+    SkASSERT(SkIsAlign16((intptr_t)storage));
+
     if (!this->computeTotalInverse(rec, nullptr)) {
         return nullptr;
     }
@@ -96,7 +100,17 @@ SkShader::Context* SkShader::onCreateContext(const ContextRec& rec, void*) const
     return nullptr;
 }
 
-size_t SkShader::contextSize(const ContextRec&) const {
+size_t SkShader::contextSize(const ContextRec& rec) const {
+    size_t size = this->onContextSize(rec);
+
+    // Currently we require each context to be allocated on 16byte boundary as some of our
+    // subclasses need that. Hence we check the size here.
+    SkASSERT(SkIsAlign16(size));
+
+    return size;
+}
+
+size_t SkShader::onContextSize(const ContextRec&) const {
     return 0;
 }