Revert "attempt 2: add experimental bilerp_clamp_8888 stage"

This reverts commit 8a64e52a98d178be13fd137b3b3a3c6aff457d85.

Reason for revert:

Test-Android-Clang-NexusPlayer-CPU-Moorefield-x86-Release-All-Android
Test-Android-Clang-NexusPlayer-GPU-PowerVR-x86-Release-All-Android

Original change's description:
> attempt 2: add experimental bilerp_clamp_8888 stage
> 
> It looks like we can specialize hot image shaders into their
> own single stages for a good speedup on both x86 and ARM.
> 
> I've started here with bilerp_clamp_8888, and will
> follow up with bgra and 565, and lowp versions of those,
> and probably also the same for nearest neighbors.
> 
> All pixels are identical in GMs.
> 
> Change-Id: Ib5ed6e528efd9e3eed96ba67d02fbec2e8133a81
> Reviewed-on: https://skia-review.googlesource.com/86860
> Reviewed-by: Mike Klein <mtklein@chromium.org>
> Commit-Queue: Mike Klein <mtklein@chromium.org>

TBR=mtklein@chromium.org,liyuqian@google.com

Change-Id: I34409a7b4aee4fd54baee44f7fc53bd0982500fe
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Reviewed-on: https://skia-review.googlesource.com/86601
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Mike Klein <mtklein@google.com>

1 files changed, 15 insertions, 34 deletions

diff --git a/src/shaders/SkImageShader.cpp b/src/shaders/SkImageShader.cpp
index 75e86c4923..ef13498ece 100644
--- a/src/shaders/SkImageShader.cpp
+++ b/src/shaders/SkImageShader.cpp
@@ -313,7 +313,7 @@ bool SkImageShader::onAppendStages(const StageRec& rec) const {
     p->append_matrix(alloc, matrix);
 
     auto gather = alloc->make<SkJumper_GatherCtx>();
-    gather->pixels = pm.addr();
+    gather->pixels = pm.writable_addr();  // Don't worry, we won't write to it.
     gather->stride = pm.rowBytesAsPixels();
     gather->width  = pm.width();
     gather->height = pm.height();
@@ -325,8 +325,6 @@ bool SkImageShader::onAppendStages(const StageRec& rec) const {
     limit_y->scale = pm.height();
     limit_y->invScale = 1.0f / pm.height();
 
-    bool is_srgb = rec.fDstCS && (!info.colorSpace() || info.gammaCloseToSRGB());
-
     auto append_tiling_and_gather = [&] {
         switch (fTileModeX) {
             case kClamp_TileMode:  /* The gather_xxx stage will clamp for us. */   break;
@@ -348,38 +346,11 @@ bool SkImageShader::onAppendStages(const StageRec& rec) const {
             case kRGBA_F16_SkColorType:  p->append(SkRasterPipeline::gather_f16,  gather); break;
             default: SkASSERT(false);
         }
-        if (is_srgb) {
+        if (rec.fDstCS && (!info.colorSpace() || info.gammaCloseToSRGB())) {
             p->append(SkRasterPipeline::from_srgb);
         }
     };
 
-    auto append_misc = [&] {
-        if (info.colorType() == kAlpha_8_SkColorType) {
-            p->append(SkRasterPipeline::set_rgb, &misc->paint_color);
-        }
-        if (info.colorType() == kAlpha_8_SkColorType ||
-            info.alphaType() == kUnpremul_SkAlphaType) {
-            p->append(SkRasterPipeline::premul);
-        }
-        if (quality > kLow_SkFilterQuality) {
-            // Bicubic filtering naturally produces out of range values on both sides.
-            p->append(SkRasterPipeline::clamp_0);
-            p->append(SkRasterPipeline::clamp_a);
-        }
-        append_gamut_transform(p, alloc, info.colorSpace(), rec.fDstCS, kPremul_SkAlphaType);
-        return true;
-    };
-
-    if (quality == kLow_SkFilterQuality            &&
-        info.colorType() == kRGBA_8888_SkColorType &&
-        fTileModeX == SkShader::kClamp_TileMode    &&
-        fTileModeY == SkShader::kClamp_TileMode    &&
-        !is_srgb) {
-
-        p->append(SkRasterPipeline::bilerp_clamp_8888, gather);
-        return append_misc();
-    }
-
     SkJumper_SamplerCtx* sampler = nullptr;
     if (quality != kNone_SkFilterQuality) {
         sampler = alloc->make<SkJumper_SamplerCtx>();
@@ -395,7 +366,6 @@ bool SkImageShader::onAppendStages(const StageRec& rec) const {
 
     if (quality == kNone_SkFilterQuality) {
         append_tiling_and_gather();
-
     } else if (quality == kLow_SkFilterQuality) {
         p->append(SkRasterPipeline::save_xy, sampler);
 
@@ -405,7 +375,6 @@ bool SkImageShader::onAppendStages(const StageRec& rec) const {
         sample(SkRasterPipeline::bilinear_px, SkRasterPipeline::bilinear_py);
 
         p->append(SkRasterPipeline::move_dst_src);
-
     } else {
         p->append(SkRasterPipeline::save_xy, sampler);
 
@@ -432,5 +401,17 @@ bool SkImageShader::onAppendStages(const StageRec& rec) const {
         p->append(SkRasterPipeline::move_dst_src);
     }
 
-    return append_misc();
+    if (info.colorType() == kAlpha_8_SkColorType) {
+        p->append(SkRasterPipeline::set_rgb, &misc->paint_color);
+    }
+    if (info.colorType() == kAlpha_8_SkColorType || info.alphaType() == kUnpremul_SkAlphaType) {
+        p->append(SkRasterPipeline::premul);
+    }
+    if (quality > kLow_SkFilterQuality) {
+        // Bicubic filtering naturally produces out of range values on both sides.
+        p->append(SkRasterPipeline::clamp_0);
+        p->append(SkRasterPipeline::clamp_a);
+    }
+    append_gamut_transform(p, alloc, info.colorSpace(), rec.fDstCS, kPremul_SkAlphaType);
+    return true;
 }