ART: Create BoundType for CheckCast early

ReferenceTypePropagation creates a BoundType for each CheckCast and
replaces all dominated uses of the casted object with it. This does
not include Phi uses on the boundary of the dominated scope, reducing
typing precision. This patch creates the BoundType in Builder, causing
SsaBuilder to replace uses of the object automatically.

Bug: 26081304

Change-Id: I083979155cccb348071ff58cb9060a896ed7d2ac

1 files changed, 22 insertions, 5 deletions

diff --git a/compiler/optimizing/nodes.cc b/compiler/optimizing/nodes.cc
index fc12224783..c85e573557 100644
--- a/compiler/optimizing/nodes.cc
+++ b/compiler/optimizing/nodes.cc
@@ -2060,6 +2060,16 @@ void HGraph::TransformLoopHeaderForBCE(HBasicBlock* header) {
   new_pre_header->SetTryCatchInformation(try_catch_info);
 }
 
+static void CheckAgainstUpperBound(ReferenceTypeInfo rti, ReferenceTypeInfo upper_bound_rti)
+    SHARED_REQUIRES(Locks::mutator_lock_) {
+  if (rti.IsValid()) {
+    DCHECK(upper_bound_rti.IsSupertypeOf(rti))
+        << " upper_bound_rti: " << upper_bound_rti
+        << " rti: " << rti;
+    DCHECK(!upper_bound_rti.GetTypeHandle()->CannotBeAssignedFromOtherTypes() || rti.IsExact());
+  }
+}
+
 void HInstruction::SetReferenceTypeInfo(ReferenceTypeInfo rti) {
   if (kIsDebugBuild) {
     DCHECK_EQ(GetType(), Primitive::kPrimNot);
@@ -2068,16 +2078,23 @@ void HInstruction::SetReferenceTypeInfo(ReferenceTypeInfo rti) {
     if (IsBoundType()) {
       // Having the test here spares us from making the method virtual just for
       // the sake of a DCHECK.
-      ReferenceTypeInfo upper_bound_rti = AsBoundType()->GetUpperBound();
-      DCHECK(upper_bound_rti.IsSupertypeOf(rti))
-          << " upper_bound_rti: " << upper_bound_rti
-          << " rti: " << rti;
-      DCHECK(!upper_bound_rti.GetTypeHandle()->CannotBeAssignedFromOtherTypes() || rti.IsExact());
+      CheckAgainstUpperBound(rti, AsBoundType()->GetUpperBound());
     }
   }
   reference_type_info_ = rti;
 }
 
+void HBoundType::SetUpperBound(const ReferenceTypeInfo& upper_bound, bool can_be_null) {
+  if (kIsDebugBuild) {
+    ScopedObjectAccess soa(Thread::Current());
+    DCHECK(upper_bound.IsValid());
+    DCHECK(!upper_bound_.IsValid()) << "Upper bound should only be set once.";
+    CheckAgainstUpperBound(GetReferenceTypeInfo(), upper_bound);
+  }
+  upper_bound_ = upper_bound;
+  upper_can_be_null_ = can_be_null;
+}
+
 ReferenceTypeInfo::ReferenceTypeInfo() : type_handle_(TypeHandle()), is_exact_(false) {}
 
 ReferenceTypeInfo::ReferenceTypeInfo(TypeHandle type_handle, bool is_exact)