Require ResultCid specification in every computation, that way we can differentiate between computa…

runtime/vm/flow_graph_optimizer.cc

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/flow_graph_optimizer.h"
 
 #include "vm/cha.h"
 #include "vm/flow_graph_builder.h"
 #include "vm/hash_map.h"
 #include "vm/il_printer.h"
@@ skipping 905 matching lines @@
     // Current bind was not removed.
     // Cache propagated computation type.
     AbstractType& computation_type =
         AbstractType::Handle(bind->computation()->CompileType());
     bool changed = bind->SetPropagatedType(computation_type);
     if (changed) {
       still_changing_ = true;
     }
     // Propagate class ids.
     intptr_t cid = bind->computation()->ResultCid();
-    changed = bind->SetPropagatedCid(cid);
-    if (changed) {
-      still_changing_ = true;
+    if (cid != kIllegalCid) {

[regis, 2012/08/24 21:30:46]

The equivalent of this test for propagated types is done inside
bind->SetPropagatedType(computation_type). You could keep the symmetry and move
this new test inside bind->SetPropagatedCid(cid).

[srdjan, 2012/08/24 21:39:20]

Done.

+      // The definition may produce result.
+      changed = bind->SetPropagatedCid(cid);
+      if (changed) {
+        still_changing_ = true;
+      }
     }
   }
 }
 
 
 void FlowGraphTypePropagator::VisitPhi(PhiInstr* phi) {
   // We could set the propagated type of the phi to the least upper bound of its
   // input propagated types. However, keeping all propagated types allows us to
   // optimize method dispatch.
   // TODO(regis): Support a set of propagated types. For now, we compute the
@@ skipping 23 matching lines @@
     }
   }
   if (merged_cid == kIllegalCid) {
     merged_cid = kDynamicCid;
   }
   changed = phi->SetPropagatedCid(merged_cid);
   if (changed) {
     still_changing_ = true;
   }
 }
 

[regis, 2012/08/24 21:30:46]

Accidental remove?

[srdjan, 2012/08/24 21:39:20]

Yes, reinstated the line.

-
 void FlowGraphTypePropagator::VisitParameter(ParameterInstr* param) {
   // TODO(regis): Once we inline functions, the propagated type of the formal
   // parameter will reflect the compile type of the passed-in argument.
   // For now, we do not know anything about the argument type and therefore set
   // it to the DynamicType, unless the argument is a compiler generated value,
   // i.e. the receiver argument or the constructor phase argument.
   AbstractType& param_type = AbstractType::Handle(Type::DynamicType());
   param->SetPropagatedCid(kDynamicCid);
   if (param->index() < 2) {
     const Function& function = parsed_function().function();
@@ skipping 79 matching lines @@
       DirectChainedHashMap<BindInstr*> child_map(*map);  // Copy map.
       OptimizeRecursive(child, &child_map);
     } else {
       OptimizeRecursive(child, map);  // Reuse map for the last child.
     }
   }
 }
 
 
 }  // namespace dart