Revert "SkRasterPipeline: 8x pipelines, attempt 2"

This reverts commit Id0ba250037e271a9475fe2f0989d64f0aa909bae.

crbug.com/654213 
Looks like Chrome Canary's picking up Haswell code on non-Haswell machines.

Change-Id: I16f976da24db86d5c99636c472ffad56db213a2a
Reviewed-on: https://skia-review.googlesource.com/3108
Commit-Queue: Mike Klein <mtklein@chromium.org>
Reviewed-by: Mike Klein <mtklein@chromium.org>

1 files changed, 15 insertions, 17 deletions

diff --git a/src/core/SkRasterPipeline.h b/src/core/SkRasterPipeline.h
index 3ef8c50d9f..996c7838e3 100644
--- a/src/core/SkRasterPipeline.h
+++ b/src/core/SkRasterPipeline.h
@@ -56,28 +56,22 @@
 class SkRasterPipeline {
 public:
     struct Stage;
-#if SK_CPU_SSE_LEVEL >= SK_CPU_SSE_LEVEL_AVX2
-    using V = Sk8f;
-#else
-    using V = Sk4f;
-#endif
-    using Fn = void(SK_VECTORCALL *)(Stage*, size_t, size_t, V,V,V,V,
-                                                             V,V,V,V);
-
+    using Fn = void(SK_VECTORCALL *)(Stage*, size_t, size_t, Sk4f,Sk4f,Sk4f,Sk4f,
+                                                             Sk4f,Sk4f,Sk4f,Sk4f);
     struct Stage {
         template <typename T>
         T ctx() { return static_cast<T>(fCtx); }
 
-        void SK_VECTORCALL next(size_t x, size_t tail, V v0, V v1, V v2, V v3,
-                                                       V v4, V v5, V v6, V v7) {
+        void SK_VECTORCALL next(size_t x, size_t tail, Sk4f v0, Sk4f v1, Sk4f v2, Sk4f v3,
+                                                       Sk4f v4, Sk4f v5, Sk4f v6, Sk4f v7) {
             // Stages are logically a pipeline, and physically are contiguous in an array.
             // To get to the next stage, we just increment our pointer to the next array element.
-            ((Fn)fNext)(this+1, x,tail, v0,v1,v2,v3, v4,v5,v6,v7);
+            fNext(this+1, x,tail, v0,v1,v2,v3, v4,v5,v6,v7);
         }
 
         // It makes next() a good bit cheaper if we hold the next function to call here,
         // rather than logically simpler choice of the function implementing this stage.
-        void (*fNext)();
+        Fn fNext;
         void* fCtx;
     };
 
@@ -90,8 +84,6 @@ public:
     void run(size_t n) { this->run(0, n); }
 
     enum StockStage {
-        just_return,
-
         store_565,
         store_srgb,
         store_f16,
@@ -142,18 +134,24 @@ public:
     void append(StockStage, void* = nullptr);
     void append(StockStage stage, const void* ctx) { this->append(stage, const_cast<void*>(ctx)); }
 
+
     // Append all stages to this pipeline.
     void extend(const SkRasterPipeline&);
 
 private:
     using Stages = SkSTArray<10, Stage, /*MEM_COPY=*/true>;
 
-    void append(void (*body)(), void (*tail)(), void*);
+    void append(Fn body, Fn tail, void*);
 
+    // This no-op default makes fBodyStart and fTailStart unconditionally safe to call,
+    // and is always the last stage's fNext as a sort of safety net to make sure even a
+    // buggy pipeline can't walk off its own end.
+    static void SK_VECTORCALL JustReturn(Stage*, size_t, size_t, Sk4f,Sk4f,Sk4f,Sk4f,
+                                                                 Sk4f,Sk4f,Sk4f,Sk4f);
     Stages fBody,
            fTail;
-    void (*fBodyStart)() = nullptr;
-    void (*fTailStart)() = nullptr;
+    Fn fBodyStart = &JustReturn,
+       fTailStart = &JustReturn;
 };
 
 #endif//SkRasterPipeline_DEFINED