VM: Correctly intrinsify implicit getters/setters when using field guards

runtime/vm/flow_graph_compiler.cc

 // Copyright (c) 2013, 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/globals.h"  // Needed here to get TARGET_ARCH_XXX.
 
 #include "vm/flow_graph_compiler.h"
 
 #include "vm/bit_vector.h"
 #include "vm/cha.h"
@@ skipping 1064 matching lines @@
   INC_STAT(Thread::Current(),
            total_code_size,
            targets.Length() * sizeof(uword));
 }
 
 
 // Returns 'true' if regular code generation should be skipped.
 bool FlowGraphCompiler::TryIntrinsify() {
   // Intrinsification skips arguments checks, therefore disable if in checked
   // mode.
-  if (FLAG_intrinsify && !isolate()->flags().type_checks()) {
+  // Only intrinsify getters/setters in precompiled code. Otherwise, unoptimized
+  // code cannot depend on guarded_cid since it may be regenerated lazily after
+  // code collection.
+  if (FLAG_precompilation &&

[Vyacheslav Egorov (Google), 2016/02/12 14:20:42]

FLAG_precompilation -> !FLAG_use_field_guards?

+      FLAG_intrinsify &&
+      !isolate()->flags().type_checks()) {
     if (parsed_function().function().kind() == RawFunction::kImplicitGetter) {
       // An implicit getter must have a specific AST structure.
       const SequenceNode& sequence_node = *parsed_function().node_sequence();
       ASSERT(sequence_node.length() == 1);
       ASSERT(sequence_node.NodeAt(0)->IsReturnNode());
       const ReturnNode& return_node = *sequence_node.NodeAt(0)->AsReturnNode();
       ASSERT(return_node.value()->IsLoadInstanceFieldNode());
       const LoadInstanceFieldNode& load_node =
           *return_node.value()->AsLoadInstanceFieldNode();
       // Only intrinsify getter if the field cannot contain a mutable double.
       // Reading from a mutable double box requires allocating a fresh double.
       if (load_node.field().guarded_cid() == kDynamicCid) {
         GenerateInlinedGetter(load_node.field().Offset());
         return true;

[Vyacheslav Egorov (Google), 2016/02/12 14:20:42]

alternatively you can do

return !FLAG_use_field_guards 

instead 

return true

then we would append the body and we will have the deoptimization target

[Florian Schneider, 2016/02/12 14:25:21]

Done.

       }
       return false;
     }
     if (parsed_function().function().kind() == RawFunction::kImplicitSetter) {
       // An implicit setter must have a specific AST structure.
       // Sequence node has one store node and one return NULL node.
       const SequenceNode& sequence_node = *parsed_function().node_sequence();
       ASSERT(sequence_node.length() == 2);
       ASSERT(sequence_node.NodeAt(0)->IsStoreInstanceFieldNode());
       ASSERT(sequence_node.NodeAt(1)->IsReturnNode());
@@ skipping 762 matching lines @@
 
 
 void FlowGraphCompiler::FrameStateClear() {
   ASSERT(!is_optimizing());
   frame_state_.TruncateTo(0);
 }
 #endif
 
 
 }  // namespace dart