Fix bug in field type tracking and polymorphic inlining.

runtime/vm/flow_graph_inliner.cc

Index: runtime/vm/flow_graph_inliner.cc
===================================================================
--- runtime/vm/flow_graph_inliner.cc	(revision 27611)
+++ runtime/vm/flow_graph_inliner.cc	(working copy)
@@ -381,8 +381,7 @@
 
 class CallSiteInliner : public ValueObject {
  public:
-  CallSiteInliner(FlowGraph* flow_graph,
-                  GrowableArray<const Field*>* guarded_fields)
+  explicit CallSiteInliner(FlowGraph* flow_graph)
       : caller_graph_(flow_graph),
         inlined_(false),
         initial_size_(flow_graph->InstructionCount()),
@@ -390,8 +389,7 @@
         inlining_depth_(1),
         collected_call_sites_(NULL),
         inlining_call_sites_(NULL),
-        function_cache_(),
-        guarded_fields_(guarded_fields) { }
+        function_cache_() { }
 
   FlowGraph* caller_graph() const { return caller_graph_; }
 
@@ -543,9 +541,11 @@
       // Build the callee graph.
       InlineExitCollector* exit_collector =
           new InlineExitCollector(caller_graph_, call);
+      GrowableArray<const Field*> inlined_guarded_fields;
       FlowGraphBuilder builder(parsed_function,
                                ic_data_array,
                                exit_collector,
+                               &inlined_guarded_fields,
                                Isolate::kNoDeoptId);
       builder.SetInitialBlockId(caller_graph_->max_block_id());
       FlowGraph* callee_graph;
@@ -606,7 +606,7 @@
                          &CompilerStats::graphinliner_opt_timer,
                          isolate);
         // TODO(zerny): Do more optimization passes on the callee graph.
-        FlowGraphOptimizer optimizer(callee_graph, guarded_fields_);
+        FlowGraphOptimizer optimizer(callee_graph);
         optimizer.ApplyICData();
         DEBUG_ASSERT(callee_graph->VerifyUseLists());
       }
@@ -667,6 +667,13 @@
       call_data->callee_graph = callee_graph;
       call_data->parameter_stubs = param_stubs;
       call_data->exit_collector = exit_collector;
+
+      // When inlined, we add the guarded fields of the callee to the caller's
+      // list of guarded fields.
+      for (intptr_t i = 0; i < inlined_guarded_fields.length(); ++i) {
+        caller_graph_->builder().AddToGuardedFields(*inlined_guarded_fields[i]);
+      }
+
       TRACE_INLINING(OS::Print("     Success\n"));
       return true;
     } else {
@@ -995,7 +1002,6 @@
   CallSites* collected_call_sites_;
   CallSites* inlining_call_sites_;
   GrowableArray<ParsedFunction*> function_cache_;
-  GrowableArray<const Field*>* guarded_fields_;
 
   DISALLOW_COPY_AND_ASSIGN(CallSiteInliner);
 };
@@ -1431,7 +1437,7 @@
     printer.PrintBlocks();
   }
 
-  CallSiteInliner inliner(flow_graph_, guarded_fields_);
+  CallSiteInliner inliner(flow_graph_);
   inliner.InlineCalls();
 
   if (inliner.inlined()) {