Object.observe: fix observation for optimised in/decrement and compound assignment.

src/hydrogen.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 5892 matching lines @@
       HValue* right = Pop();
       HValue* left = Pop();
 
       HInstruction* instr = BuildBinaryOperation(operation, left, right);
       PushAndAdd(instr);
       if (instr->HasObservableSideEffects()) {
         AddSimulate(operation->id(), REMOVABLE_SIMULATE);
       }
 
       HInstruction* store;
-      if (!monomorphic) {
+      if (!monomorphic || map->is_observed()) {
         // If we don't know the monomorphic type, do a generic store.
         CHECK_ALIVE(store = BuildStoreNamedGeneric(object, name, instr));
       } else {
         Handle<JSFunction> setter;
         Handle<JSObject> holder;
         if (LookupSetter(map, name, &setter, &holder)) {
           store = BuildCallSetter(object, instr, map, setter, holder);
         } else {
           CHECK_ALIVE(store = BuildStoreNamedMonomorphic(object,
                                                          name,
@@ skipping 2334 matching lines @@
       }
       PushAndAdd(load);
       if (load->HasObservableSideEffects()) {
         AddSimulate(prop->LoadId(), REMOVABLE_SIMULATE);
       }
 
       after = BuildIncrement(returns_original_input, expr);
       input = Pop();
 
       HInstruction* store;
-      if (!monomorphic) {
+      if (!monomorphic || map->is_observed()) {
         // If we don't know the monomorphic type, do a generic store.
         CHECK_ALIVE(store = BuildStoreNamedGeneric(object, name, after));
       } else {
         Handle<JSFunction> setter;
         Handle<JSObject> holder;
         if (LookupSetter(map, name, &setter, &holder)) {
           store = BuildCallSetter(object, after, map, setter, holder);
         } else {
           CHECK_ALIVE(store = BuildStoreNamedMonomorphic(object,
                                                          name,
@@ skipping 1915 matching lines @@
     }
   }
 
 #ifdef DEBUG
   if (graph_ != NULL) graph_->Verify(false);  // No full verify.
   if (allocator_ != NULL) allocator_->Verify();
 #endif
 }
 
 } }  // namespace v8::internal