Remove unreachable exits from the list collected by InlineExitCollector.

runtime/vm/flow_graph_builder.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_builder.h"
 
 #include "lib/invocation_mirror.h"
 #include "vm/ast_printer.h"
 #include "vm/bit_vector.h"
 #include "vm/compiler.h"
@@ skipping 354 matching lines @@
       // optimizations need deoptimization info for non-deoptable instructions,
       // eg, LICM on GOTOs.
       if (instr->env() != NULL) {
         call_->env()->DeepCopyToOuter(callee_graph->zone(), instr);
       }
     }
     if (instr->IsGoto()) {
       instr->AsGoto()->adjust_edge_weight(scale_factor);
     }
   }
+
+  RemoveUnreachableExits(callee_graph);
 }
 
 
 void InlineExitCollector::AddExit(ReturnInstr* exit) {
   Data data = { NULL, exit };
   exits_.Add(data);
 }
 
 
 void InlineExitCollector::Union(const InlineExitCollector* other) {
   // It doesn't make sense to combine different calls or calls from
   // different graphs.
   ASSERT(caller_graph_ == other->caller_graph_);
   ASSERT(call_ == other->call_);
   exits_.AddArray(other->exits_);
 }
 
 
 int InlineExitCollector::LowestBlockIdFirst(const Data* a, const Data* b) {
   return (a->exit_block->block_id() - b->exit_block->block_id());
 }
 
 
+void InlineExitCollector::RemoveUnreachableExits(FlowGraph* callee_graph) {
+  const GrowableArray<BlockEntryInstr*>& postorder = callee_graph->postorder();
+  int j = 0;
+  for (int i = 0; i < exits_.length(); ++i) {
+    BlockEntryInstr* block = exits_[i].exit_return->GetBlock();
+    if ((block != NULL) &&
+        (0 <= block->postorder_number()) &&
+        (block->postorder_number() < postorder.length()) &&
+        (postorder[block->postorder_number()] == block)) {
+      if (i != j) {
+        exits_[j] = exits_[i];
+      }
+      j++;
+    }
+  }
+  exits_.TruncateTo(j);
+}
+
+
 void InlineExitCollector::SortExits() {
   // Assign block entries here because we did not necessarily know them when
   // the return exit was added to the array.
   for (int i = 0; i < exits_.length(); ++i) {
     exits_[i].exit_block = exits_[i].exit_return->GetBlock();
   }
   exits_.Sort(LowestBlockIdFirst);
 }
 
 
@@ skipping 4184 matching lines @@
   Report::MessageF(Report::kBailout,
                    Script::Handle(function.script()),
                    function.token_pos(),
                    "FlowGraphBuilder Bailout: %s %s",
                    String::Handle(function.name()).ToCString(),
                    reason);
   UNREACHABLE();
 }
 
 }  // namespace dart