VM: Propagate non-nullness from instance calls.

runtime/vm/flow_graph.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.h"
 
 #include "vm/bit_vector.h"
 #include "vm/cha.h"
 #include "vm/flow_graph_builder.h"
 #include "vm/flow_graph_compiler.h"
@@ skipping 402 matching lines @@
       if ((use != NULL) && (use->is_receiver() == PhiInstr::kReceiver)) {
         use->set_is_receiver(PhiInstr::kNotReceiver);
         unmark.Add(use);
       }
     }
   }
 }
 
 
 bool FlowGraph::IsReceiver(Definition* def) const {
+  def = def->OriginalDefinition();  // Could be redefined.
   if (def->IsParameter()) return (def->AsParameter()->index() == 0);
   if (!def->IsPhi() || graph_entry()->catch_entries().is_empty()) return false;
   PhiInstr* phi = def->AsPhi();
   if (phi->is_receiver() != PhiInstr::kUnknownReceiver) {
     return (phi->is_receiver() == PhiInstr::kReceiver);
   }
   // Not known if this phi is the receiver yet. Compute it now.
   ComputeIsReceiver(phi);
   return (phi->is_receiver() == PhiInstr::kReceiver);
 }
@@ skipping 852 matching lines @@
     }
   }
 
   for (BlockIterator it(postorder_iterator()); !it.Done(); it.Advance()) {
     JoinEntryInstr* join = it.Current()->AsJoinEntry();
     if (join != NULL) join->RemoveDeadPhis(constant_dead());
   }
 }
 
 
-RedefinitionInstr* FlowGraph::EnsureRedefinition(BlockEntryInstr* block,
+RedefinitionInstr* FlowGraph::EnsureRedefinition(Instruction* prev,
                                                  Definition* original,
                                                  CompileType compile_type) {
-  RedefinitionInstr* first = block->next()->AsRedefinition();
-  if (first != NULL && (first->type() != NULL)) {
+  RedefinitionInstr* first = prev->next()->AsRedefinition();
+  if (first != NULL && (first->constrained_type() != NULL)) {
     if ((first->value()->definition() == original) &&
-        first->type()->IsEqualTo(&compile_type)) {
+        first->constrained_type()->IsEqualTo(&compile_type)) {
       // Already redefined. Do nothing.
       return NULL;
     }
   }
   RedefinitionInstr* redef = new RedefinitionInstr(new Value(original));
-  redef->set_type(new CompileType(compile_type));
-  InsertAfter(block, redef, NULL, FlowGraph::kValue);
+  redef->set_constrained_type(new CompileType(compile_type));
+  InsertAfter(prev, redef, NULL, FlowGraph::kValue);
   RenameDominatedUses(original, redef, redef);
   return redef;
 }
 
 
 void FlowGraph::RemoveRedefinitions() {
   // Remove redefinition instructions inserted to inhibit hoisting.
   for (BlockIterator block_it = reverse_postorder_iterator(); !block_it.Done();
        block_it.Advance()) {
     for (ForwardInstructionIterator instr_it(block_it.Current());
@@ skipping 979 matching lines @@
                                                 Representation rep,
                                                 intptr_t cid) {
   ExtractNthOutputInstr* extract =
       new (Z) ExtractNthOutputInstr(new (Z) Value(instr), index, rep, cid);
   instr->ReplaceUsesWith(extract);
   InsertAfter(instr, extract, NULL, FlowGraph::kValue);
 }
 
 
 }  // namespace dart