Do not recompute unary_checks repeatedly. Add special (and quicker) way to check for method overrides using CHA.

Review URL: https://codereview.chromium.org//11275110

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@14434 260f80e4-7a28-3924-810f-c04153c831b5

runtime/vm/cha.cc

@@ -70,6 +70,27 @@ ZoneGrowableArray<intptr_t>* CHA::GetSubclassIdsOf(intptr_t cid) {
 }
 
 
+bool CHA::HasOverride(const Class& cls, const String& function_name) {
+  const GrowableObjectArray& cls_direct_subclasses =
+      GrowableObjectArray::Handle(cls.direct_subclasses());
+  if (cls_direct_subclasses.IsNull()) {
+    return false;
+  }
+  Class& direct_subclass = Class::Handle();
+  for (intptr_t i = 0; i < cls_direct_subclasses.Length(); i++) {
+    direct_subclass ^= cls_direct_subclasses.At(i);
+    if (direct_subclass.LookupDynamicFunction(function_name) !=
+        Function::null()) {
+      return true;
+    }
+    if (HasOverride(direct_subclass, function_name)) {
+      return true;
+    }
+  }
+  return false;
+}
+
+
 ZoneGrowableArray<Function*>* CHA::GetNamedInstanceFunctionsOf(
     const ZoneGrowableArray<intptr_t>& cids,
     const String& function_name) {

runtime/vm/cha.h

@@ -9,6 +9,7 @@
 
 namespace dart {
 
+class Class;
 class Function;
 template <typename T> class ZoneGrowableArray;
 class String;
@@ -33,6 +34,9 @@ class CHA : public AllStatic {
   // Returns an array of functions overriding the given function.
   // Must not be called for a function of class Object.
   static ZoneGrowableArray<Function*>* GetOverridesOf(const Function& function);
+
+  // Returns true if any subclass of 'cls' contains the function.
+  static bool HasOverride(const Class& cls, const String& function_name);
 };
 
 }  // namespace dart

runtime/vm/flow_graph_optimizer.cc

@@ -876,19 +876,8 @@ bool FlowGraphOptimizer::InstanceCallNeedsClassCheck(
   if (function.IsDynamicFunction() &&
       callee_receiver->IsParameter() &&
       (callee_receiver->AsParameter()->index() == 0)) {
-    const intptr_t static_receiver_cid = Class::Handle(function.Owner()).id();
-    ZoneGrowableArray<intptr_t>* subclass_cids =
-        CHA::GetSubclassIdsOf(static_receiver_cid);
-    if (subclass_cids->is_empty()) {
-      // No subclasses, no check needed.
-      return false;
-    }
-    ZoneGrowableArray<Function*>* overriding_functions =
-        CHA::GetNamedInstanceFunctionsOf(*subclass_cids, call->function_name());
-    if (overriding_functions->is_empty()) {
-      // No overriding functions.
-      return false;
-    }
+    return CHA::HasOverride(Class::Handle(function.Owner()),
+                            call->function_name());
   }
   return true;
 }
@@ -1155,7 +1144,8 @@ void FlowGraphOptimizer::VisitInstanceCall(InstanceCallInstr* instr) {
   if ((op_kind == Token::kGET) && TryInlineInstanceGetter(instr)) {
     return;
   }
-  if ((op_kind == Token::kSET) && TryInlineInstanceSetter(instr)) {
+  if ((op_kind == Token::kSET) &&
+      TryInlineInstanceSetter(instr, unary_checks)) {
     return;
   }
   if (TryInlineInstanceMethod(instr)) {
@@ -1198,15 +1188,16 @@ void FlowGraphOptimizer::VisitStaticCall(StaticCallInstr* call) {
 }
 
 
-bool FlowGraphOptimizer::TryInlineInstanceSetter(InstanceCallInstr* instr) {
+bool FlowGraphOptimizer::TryInlineInstanceSetter(InstanceCallInstr* instr,
+                                                 const ICData& unary_ic_data) {
+  ASSERT((unary_ic_data.NumberOfChecks() > 0) &&
+      (unary_ic_data.num_args_tested() == 1));
   if (FLAG_enable_type_checks) {
     // TODO(srdjan): Add assignable check node if --enable_type_checks.
     return false;
   }
 
   ASSERT(instr->HasICData());
-  const ICData& unary_ic_data =
-      ICData::Handle(instr->ic_data()->AsUnaryClassChecks());
   if (unary_ic_data.NumberOfChecks() == 0) {
     // No type feedback collected.
     return false;

runtime/vm/flow_graph_optimizer.h

@@ -63,7 +63,8 @@ class FlowGraphOptimizer : public FlowGraphVisitor {
   bool TryReplaceWithUnaryOp(InstanceCallInstr* call, Token::Kind op_kind);
 
   bool TryInlineInstanceGetter(InstanceCallInstr* call);
-  bool TryInlineInstanceSetter(InstanceCallInstr* call);
+  bool TryInlineInstanceSetter(InstanceCallInstr* call,
+                               const ICData& unary_ic_data);
 
   bool TryInlineInstanceMethod(InstanceCallInstr* call);