Eliminate unused function maps

runtime/vm/object.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/object.h"
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "vm/assembler.h"
 #include "vm/cpu.h"
@@ skipping 2150 matching lines @@
     return name.Hash();
   }
 };
 typedef UnorderedHashSet<ClassFunctionsTraits> ClassFunctionsSet;
 
 
 void Class::SetFunctions(const Array& value) const {
   ASSERT(!value.IsNull());
   StorePointer(&raw_ptr()->functions_, value.raw());
   const intptr_t len = value.Length();
-  ClassFunctionsSet set(HashTables::New<ClassFunctionsSet>(len, Heap::kOld));
   if (len >= kFunctionLookupHashTreshold) {
+    ClassFunctionsSet set(HashTables::New<ClassFunctionsSet>(len, Heap::kOld));
     Function& func = Function::Handle();
     for (intptr_t i = 0; i < len; ++i) {
       func ^= value.At(i);
       // Verify that all the functions in the array have this class as owner.
       ASSERT(func.Owner() == raw());
       set.Insert(func);
     }
+    StorePointer(&raw_ptr()->functions_hash_table_, set.Release().raw());
   }
-  StorePointer(&raw_ptr()->functions_hash_table_, set.Release().raw());
 }
 
 
 void Class::AddFunction(const Function& function) const {
   const Array& arr = Array::Handle(functions());
   const Array& new_arr =
       Array::Handle(Array::Grow(arr, arr.Length() + 1, Heap::kOld));
   new_arr.SetAt(arr.Length(), function);
   StorePointer(&raw_ptr()->functions_, new_arr.raw());
   // Add to hash table, if any.
   const intptr_t new_len = new_arr.Length();
   if (new_len == kFunctionLookupHashTreshold) {
     // Transition to using hash table.
     SetFunctions(new_arr);
   } else if (new_len > kFunctionLookupHashTreshold) {
     ClassFunctionsSet set(raw_ptr()->functions_hash_table_);
     set.Insert(function);
     StorePointer(&raw_ptr()->functions_hash_table_, set.Release().raw());
   }
 }
 
 
 void Class::RemoveFunction(const Function& function) const {
   const Array& arr = Array::Handle(functions());
   StorePointer(&raw_ptr()->functions_, Object::empty_array().raw());
+  StorePointer(&raw_ptr()->functions_hash_table_, Array::null());
   Function& entry = Function::Handle();
   for (intptr_t i = 0; i < arr.Length(); i++) {
     entry ^= arr.At(i);
     if (function.raw() != entry.raw()) {
       AddFunction(entry);
     }
   }
 }
 
 
@@ skipping 19490 matching lines @@
   return tag_label.ToCString();
 }
 
 
 void UserTag::PrintJSONImpl(JSONStream* stream, bool ref) const {
   Instance::PrintJSONImpl(stream, ref);
 }
 
 
 }  // namespace dart