Revert "Reland "Use off-heap data for type feedback in PolymorphicInstanceCallInstr""

runtime/vm/jit_optimizer.cc

Index: runtime/vm/jit_optimizer.cc
diff --git a/runtime/vm/jit_optimizer.cc b/runtime/vm/jit_optimizer.cc
index fb6ee1d43be1d01be334cbb573a14b2f57af868e..bdfcddcf09c00fd4e391dfcdc6dc4debc786c0ba 100644
--- a/runtime/vm/jit_optimizer.cc
+++ b/runtime/vm/jit_optimizer.cc
@@ -209,13 +209,9 @@ void JitOptimizer::SpecializePolymorphicInstanceCall(
     return;  // No information about receiver was infered.
   }
 
-  const ICData& ic_data = *call->instance_call()->ic_data();
-
-  const CallTargets* targets =
-      FlowGraphCompiler::ResolveCallTargetsForReceiverCid(
-          receiver_cid, String::Handle(zone(), ic_data.target_name()),
-          Array::Handle(zone(), ic_data.arguments_descriptor()));
-  if (targets == NULL) {
+  const ICData& ic_data = FlowGraphCompiler::TrySpecializeICDataByReceiverCid(
+      call->ic_data(), receiver_cid);
+  if (ic_data.raw() == call->ic_data().raw()) {
     // No specialization.
     return;
   }
@@ -223,7 +219,7 @@ void JitOptimizer::SpecializePolymorphicInstanceCall(
   const bool with_checks = false;
   const bool complete = false;
   PolymorphicInstanceCallInstr* specialized =
-      new (Z) PolymorphicInstanceCallInstr(call->instance_call(), *targets,
+      new (Z) PolymorphicInstanceCallInstr(call->instance_call(), ic_data,
                                            with_checks, complete);
   call->ReplaceWith(specialized, current_iterator());
 }
@@ -1452,6 +1448,85 @@ void JitOptimizer::ReplaceWithTypeCast(InstanceCallInstr* call) {
 }
 
 
+bool JitOptimizer::LookupMethodFor(int class_id,
+                                   const ArgumentsDescriptor& args_desc,
+                                   const String& name,
+                                   Function* fn_return) {
+  if (class_id < 0) return false;
+  if (class_id >= I->class_table()->NumCids()) return false;
+
+  RawClass* raw_class = I->class_table()->At(class_id);
+  if (raw_class == NULL) return false;
+  Class& cls = Class::Handle(Z, raw_class);
+  if (cls.IsNull()) return false;
+  if (!cls.is_finalized()) return false;
+  if (Array::Handle(cls.functions()).IsNull()) return false;
+
+  bool allow_add = false;
+  Function& target_function =
+      Function::Handle(Z, Resolver::ResolveDynamicForReceiverClass(
+                              cls, name, args_desc, allow_add));
+  if (target_function.IsNull()) return false;
+  *fn_return ^= target_function.raw();
+  return true;
+}
+
+
+static int OrderById(const intptr_t* a, const intptr_t* b) {
+  // Negative if 'a' should sort before 'b'.
+  return *a - *b;
+}
+
+
+void JitOptimizer::TryExpandClassesInICData(const ICData& ic_data) {
+  if (ic_data.NumberOfChecks() == 0) return;
+
+  Function& dummy = Function::Handle(Z);
+
+  GrowableArray<intptr_t> ids;
+  for (int i = 0; i < ic_data.NumberOfChecks(); i++) {
+    // The API works for multi dispatch ICs that check more than one argument,
+    // but we know we only check one arg here, so only the 0th element of id
+    // will be used.
+    GrowableArray<intptr_t> id;
+    ic_data.GetCheckAt(i, &id, &dummy);
+    ids.Add(id[0]);
+  }
+  ids.Sort(OrderById);
+
+  Array& args_desc_array = Array::Handle(Z, ic_data.arguments_descriptor());
+  ArgumentsDescriptor args_desc(args_desc_array);
+  String& name = String::Handle(Z, ic_data.target_name());
+
+  Function& fn = Function::Handle(Z);
+  Function& fn_high = Function::Handle(Z);
+  Function& possible_match = Function::Handle(Z);
+
+  for (int cid_index = 0; cid_index < ids.length() - 1; cid_index++) {
+    int low_cid = ids[cid_index];
+    int high_cid = ids[cid_index + 1];
+    if (low_cid + 1 == high_cid) continue;
+    if (LookupMethodFor(low_cid, args_desc, name, &fn) &&
+        LookupMethodFor(high_cid, args_desc, name, &fn_high) &&
+        fn.raw() == fn_high.raw()) {
+      // Try to fill in the IC table by going downwards from a known class-id.
+      bool can_fill_in = true;
+      for (int i = low_cid + 1; i < high_cid; i++) {
+        if (!LookupMethodFor(i, args_desc, name, &possible_match) ||
+            possible_match.raw() != fn.raw()) {
+          can_fill_in = false;
+          break;
+        }
+      }
+      if (can_fill_in) {
+        for (int i = low_cid + 1; i < high_cid; i++) {
+          ic_data.AddReceiverCheck(i, fn, 0);
+        }
+      }
+    }
+  }
+}
+
 // Tries to optimize instance call by replacing it with a faster instruction
 // (e.g, binary op, field load, ..).
 void JitOptimizer::VisitInstanceCall(InstanceCallInstr* instr) {
@@ -1509,9 +1584,11 @@ void JitOptimizer::VisitInstanceCall(InstanceCallInstr* instr) {
     return;
   }
 
-  CallTargets* targets = CallTargets::Create(Z, unary_checks);
+  // Now we are done trying the inlining options that benefit from only having
+  // 1 entry in the IC table.
+  TryExpandClassesInICData(unary_checks);
 
-  bool has_one_target = targets->HasSingleTarget();
+  bool has_one_target = unary_checks.HasOneTarget();
 
   if (has_one_target) {
     // Check if the single target is a polymorphic target, if it is,
@@ -1519,7 +1596,7 @@ void JitOptimizer::VisitInstanceCall(InstanceCallInstr* instr) {
     const Function& target = Function::Handle(Z, unary_checks.GetTargetAt(0));
     if (target.recognized_kind() == MethodRecognizer::kObjectRuntimeType) {
       has_one_target = PolymorphicInstanceCallInstr::ComputeRuntimeType(
-                           *targets) != Type::null();
+                           unary_checks) != Type::null();
     } else {
       const bool polymorphic_target =
           MethodRecognizer::PolymorphicTarget(target);
@@ -1532,7 +1609,7 @@ void JitOptimizer::VisitInstanceCall(InstanceCallInstr* instr) {
     const RawFunction::Kind function_kind = target.kind();
     if (!flow_graph()->InstanceCallNeedsClassCheck(instr, function_kind)) {
       PolymorphicInstanceCallInstr* call =
-          new (Z) PolymorphicInstanceCallInstr(instr, *targets,
+          new (Z) PolymorphicInstanceCallInstr(instr, unary_checks,
                                                /* call_with_checks = */ false,
                                                /* complete = */ false);
       instr->ReplaceWith(call, current_iterator());
@@ -1555,17 +1632,15 @@ void JitOptimizer::VisitInstanceCall(InstanceCallInstr* instr) {
       (!instr->ic_data()->HasDeoptReason(ICData::kDeoptCheckClass) ||
        unary_checks.NumberOfChecks() <= FLAG_max_polymorphic_checks)) {
     // Type propagation has not run yet, we cannot eliminate the check.
-    // TODO(erikcorry): The receiver check should use the off-heap targets
-    // array, not the IC array.
     AddReceiverCheck(instr);
     // Call can still deoptimize, do not detach environment from instr.
     call_with_checks = false;
   } else {
     call_with_checks = true;
   }
-  PolymorphicInstanceCallInstr* call =
-      new (Z) PolymorphicInstanceCallInstr(instr, *targets, call_with_checks,
-                                           /* complete = */ false);
+  PolymorphicInstanceCallInstr* call = new (Z)
+      PolymorphicInstanceCallInstr(instr, unary_checks, call_with_checks,
+                                   /* complete = */ false);
   instr->ReplaceWith(call, current_iterator());
 }