Noop away PushCull/PopCull pairs with nothing between them.

BUG=skia:2378
R=fmalita@chromium.org, mtklein@google.com

Author: mtklein@chromium.org

Review URL: https://codereview.chromium.org/277613002

git-svn-id: http://skia.googlecode.com/svn/trunk@14653 2bbb7eff-a529-9590-31e7-b0007b416f81

2 files changed, 19 insertions, 0 deletions

diff --git a/src/record/SkRecordOpts.cpp b/src/record/SkRecordOpts.cpp
index bfc45bda5a..1322c0f1e5 100644
--- a/src/record/SkRecordOpts.cpp
+++ b/src/record/SkRecordOpts.cpp
@@ -15,8 +15,10 @@ using namespace SkRecords;
 
 void SkRecordOptimize(SkRecord* record) {
     // TODO(mtklein): fuse independent optimizations to reduce number of passes?
+    SkRecordNoopCulls(record);
     SkRecordNoopSaveRestores(record);
     SkRecordNoopSaveLayerDrawRestores(record);
+
     SkRecordAnnotateCullingPairs(record);
     SkRecordReduceDrawPosTextStrength(record);  // Helpful to run this before BoundDrawPosTextH.
     SkRecordBoundDrawPosTextH(record);
@@ -42,6 +44,21 @@ static bool apply(Pass* pass, SkRecord* record) {
     return changed;
 }
 
+struct CullNooper {
+    typedef Pattern3<Is<PushCull>, Star<Is<NoOp> >, Is<PopCull> > Pattern;
+
+    bool onMatch(SkRecord* record, Pattern* pattern, unsigned begin, unsigned end) {
+        record->replace<NoOp>(begin);  // PushCull
+        record->replace<NoOp>(end-1);  // PopCull
+        return true;
+    }
+};
+
+void SkRecordNoopCulls(SkRecord* record) {
+    CullNooper pass;
+    while (apply(&pass, record));
+}
+
 // Turns the logical NoOp Save and Restore in Save-Draw*-Restore patterns into actual NoOps.
 struct SaveOnlyDrawsRestoreNooper {
     typedef Pattern3<Is<Save>,
diff --git a/src/record/SkRecordOpts.h b/src/record/SkRecordOpts.h
index ad8c3bcfc7..b535ec958a 100644
--- a/src/record/SkRecordOpts.h
+++ b/src/record/SkRecordOpts.h
@@ -13,6 +13,8 @@
 // Run all optimizations in recommended order.
 void SkRecordOptimize(SkRecord*);
 
+// NoOp away pointless PushCull/PopCull pairs with nothing between them.
+void SkRecordNoopCulls(SkRecord*);
 
 // Turns logical no-op Save-[non-drawing command]*-Restore patterns into actual no-ops.
 void SkRecordNoopSaveRestores(SkRecord*);