Temporary fix for OOM in precompilation with very large methods.

runtime/vm/redundancy_elimination.cc

 // Copyright (c) 2016, 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/redundancy_elimination.h"
 
 #include "vm/bit_vector.h"
 #include "vm/flow_graph.h"
 #include "vm/hash_map.h"
 #include "vm/il_printer.h"
@@ skipping 1531 matching lines @@
 
   Isolate* isolate() const { return graph_->isolate(); }
   Zone* zone() const { return graph_->zone(); }
 
   static bool OptimizeGraph(FlowGraph* graph) {
     ASSERT(FLAG_load_cse);
     if (FLAG_trace_load_optimization) {
       FlowGraphPrinter::PrintGraph("Before LoadOptimizer", graph);
     }
 
+    // For now, bail out for large functions to avoid OOM situations.
+    // TODO(fschneider): Fix the memory consumption issue.
+    intptr_t function_length =
+        graph->function().end_token_pos().Pos() -
+        graph->function().token_pos().Pos();
+    if (function_length >= FLAG_huge_method_cutoff_in_tokens) {
+      return false;
+    }
+
     DirectChainedHashMap<PointerKeyValueTrait<Place> > map;
     AliasedSet* aliased_set = NumberPlaces(graph, &map, kOptimizeLoads);
     if ((aliased_set != NULL) && !aliased_set->IsEmpty()) {
       // If any loads were forwarded return true from Optimize to run load
       // forwarding again. This will allow to forward chains of loads.
       // This is especially important for context variables as they are built
       // as loads from loaded context.
       // TODO(vegorov): renumber newly discovered congruences during the
       // forwarding to forward chains without running whole pass twice.
       LoadOptimizer load_optimizer(graph, aliased_set);
@@ skipping 945 matching lines @@
       exposed_stores_.Add(NULL);
     }
   }
 
   static void OptimizeGraph(FlowGraph* graph) {
     ASSERT(FLAG_load_cse);
     if (FLAG_trace_load_optimization) {
       FlowGraphPrinter::PrintGraph("Before StoreOptimizer", graph);
     }
 
+    // For now, bail out for large functions to avoid OOM situations.
+    // TODO(fschneider): Fix the memory consumption issue.
+    intptr_t function_length =
+        graph->function().end_token_pos().Pos() -
+        graph->function().token_pos().Pos();
+    if (function_length >= FLAG_huge_method_cutoff_in_tokens) {
+      return;
+    }
+
     DirectChainedHashMap<PointerKeyValueTrait<Place> > map;
     AliasedSet* aliased_set = NumberPlaces(graph, &map, kOptimizeStores);
     if ((aliased_set != NULL) && !aliased_set->IsEmpty()) {
       StoreOptimizer store_optimizer(graph, aliased_set, &map);
       store_optimizer.Optimize();
     }
   }
 
  private:
   void Optimize() {
@@ skipping 937 matching lines @@
         join->phis_ = NULL;
       } else {
         join->phis_->TruncateTo(to_index);
       }
     }
   }
 }
 
 
 }  // namespace dart