Add a write barrier elimination pass

We can eliminate redundant write barriers as we don't need several
for the same receiver. For example:

```
MyObject o;
o.inner_obj = io;
o.inner_obj2 = io2;
o.inner_obj3 = io3;
```

We can keep the write barrier for `inner_obj` and remove the other
two.

Note that we cannot perform this optimization across
invokes, suspend check, or instructions that can throw.

Local improvements (pixel 5, speed compile):
 * System server: -280KB (-0.56%)
 * SystemUIGoogle: -330KB (-1.16%)
 * AGSA: -3876KB (-1.19%)

Bug: 260843353
Fixes: 260843353
Change-Id: Ibf98efbe891ee00e46125853c3e97ae30aa3ff30

1 files changed, 5 insertions, 1 deletions

diff --git a/compiler/optimizing/graph_visualizer.cc b/compiler/optimizing/graph_visualizer.cc
index f6076525d8..96eaa61209 100644
--- a/compiler/optimizing/graph_visualizer.cc
+++ b/compiler/optimizing/graph_visualizer.cc
@@ -483,6 +483,7 @@ class HGraphVisualizerPrinter : public HGraphDelegateVisitor {
     StartAttributeStream("can_trigger_gc")
         << std::boolalpha << array_set->GetSideEffects().Includes(SideEffects::CanTriggerGC())
         << std::noboolalpha;
+    StartAttributeStream("write_barrier_kind") << array_set->GetWriteBarrierKind();
   }
 
   void VisitCompare(HCompare* compare) override {
@@ -552,7 +553,9 @@ class HGraphVisualizerPrinter : public HGraphDelegateVisitor {
         iset->GetFieldInfo().GetDexFile().PrettyField(iset->GetFieldInfo().GetFieldIndex(),
                                                       /* with type */ false);
     StartAttributeStream("field_type") << iset->GetFieldType();
-    StartAttributeStream("predicated") << std::boolalpha << iset->GetIsPredicatedSet();
+    StartAttributeStream("predicated")
+        << std::boolalpha << iset->GetIsPredicatedSet() << std::noboolalpha;
+    StartAttributeStream("write_barrier_kind") << iset->GetWriteBarrierKind();
   }
 
   void VisitStaticFieldGet(HStaticFieldGet* sget) override {
@@ -567,6 +570,7 @@ class HGraphVisualizerPrinter : public HGraphDelegateVisitor {
         sset->GetFieldInfo().GetDexFile().PrettyField(sset->GetFieldInfo().GetFieldIndex(),
                                                       /* with type */ false);
     StartAttributeStream("field_type") << sset->GetFieldType();
+    StartAttributeStream("write_barrier_kind") << sset->GetWriteBarrierKind();
   }
 
   void VisitUnresolvedInstanceFieldGet(HUnresolvedInstanceFieldGet* field_access) override {