Lookup getter/setter symbols before alllocating them, thus eliminating extra String allocations in …

runtime/vm/symbols.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/symbols.h"
 
 #include "vm/handles.h"
 #include "vm/handles_impl.h"
 #include "vm/hash_table.h"
 #include "vm/isolate.h"
@@ skipping 474 matching lines @@
     SymbolTable table(zone, isolate->object_store()->symbol_table());
     symbol ^= table.InsertNewOrGet(str);
     isolate->object_store()->set_symbol_table(table.Release());
   }
   ASSERT(symbol.IsSymbol());
   ASSERT(symbol.HasHash());
   return symbol.raw();
 }
 
 
+template<typename StringType>
+RawString* Symbols::Lookup(const StringType& str) {
+  Thread* thread = Thread::Current();
+  Isolate* isolate = thread->isolate();
+  Zone* zone = thread->zone();
+  String& symbol = String::Handle(zone);
+  {
+    Isolate* vm_isolate = Dart::vm_isolate();
+    SymbolTable table(zone, vm_isolate->object_store()->symbol_table());
+    symbol ^= table.GetOrNull(str);
+    table.Release();
+  }
+  if (symbol.IsNull()) {
+    SymbolTable table(zone, isolate->object_store()->symbol_table());
+    symbol ^= table.GetOrNull(str);
+    table.Release();
+  }
+
+  ASSERT(symbol.IsNull() || symbol.IsSymbol());
+  ASSERT(symbol.IsNull() || symbol.HasHash());
+  return symbol.raw();
+}
+
+
+RawString* Symbols::LookupFromConcat(const String& str1, const String& str2) {
+  if (str1.Length() == 0) {
+    return Lookup(str2);
+  } else if (str2.Length() == 0) {
+    return Lookup(str1);
+  } else {
+    return Lookup(ConcatString(str1, str2));
+  }
+}
+
+
 RawString* Symbols::New(const String& str) {
   if (str.IsSymbol()) {
     return str.raw();
   }
   return New(str, 0, str.Length());
 }
 
 
 RawString* Symbols::New(const String& str, intptr_t begin_index, intptr_t len) {
   return NewSymbol(StringSlice(str, begin_index, len));
@@ skipping 39 matching lines @@
 RawObject* Symbols::GetVMSymbol(intptr_t object_id) {
   ASSERT(IsVMSymbolId(object_id));
   intptr_t i = (object_id - kMaxPredefinedObjectIds);
   if ((i > kIllegal) && (i < Symbols::kMaxPredefinedId)) {
     return symbol_handles_[i]->raw();
   }
   return Object::null();
 }
 
 }  // namespace dart