Convert all symbols accessor to return read only handles so that it is not necessary to create a ne…

vm/flow_graph_optimizer.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/flow_graph_optimizer.h"
 
 #include "vm/bit_vector.h"
 #include "vm/cha.h"
 #include "vm/flow_graph_builder.h"
 #include "vm/flow_graph_compiler.h"
@@ skipping 594 matching lines @@
       default:
         // TODO(fschneider): Add support for other array types.
         UNREACHABLE();
     }
     AssertAssignableInstr* assert_value =
         new AssertAssignableInstr(call->token_pos(),
                                   value->Copy(),
                                   instantiator,
                                   type_args,
                                   value_type,
-                                  String::ZoneHandle(Symbols::New("value")));
+                                  Symbols::Value());
     InsertBefore(call, assert_value, NULL, Definition::kValue);
   }
 
   Value* array = NULL;
   Value* index = NULL;
   intptr_t array_cid = PrepareIndexedOp(call, class_id, &array, &index);
   Value* value = call->ArgumentAt(2)->value();
   // Check if store barrier is needed.
   bool needs_store_barrier = true;
   if ((class_id == kFloat32ArrayCid) || (class_id == kFloat64ArrayCid)) {
@@ skipping 1887 matching lines @@
     instr->ReplaceUsesWith(result);
     ASSERT(current_iterator()->Current() == instr);
     current_iterator()->RemoveCurrentFromGraph();
     if (FLAG_trace_optimization) {
       OS::Print("Replacing v%"Pd" with v%"Pd"\n",
                 instr->ssa_temp_index(),
                 result->ssa_temp_index());
     }
 
     if (FLAG_trace_type_check_elimination) {
-      const String& name = String::Handle(Symbols::New("boolean expression"));
       FlowGraphPrinter::PrintTypeCheck(parsed_function(),
                                        instr->token_pos(),
                                        instr->value(),
                                        Type::Handle(Type::BoolType()),
-                                       name,
+                                       Symbols::BooleanExpression(),
                                        instr->is_eliminated());
     }
   }
 }
 
 
 void FlowGraphTypePropagator::VisitInstanceOf(InstanceOfInstr* instr) {
   bool is_null;
   bool is_instance = false;
   if (FLAG_eliminate_type_checks &&
       instr->value()->CanComputeIsNull(&is_null) &&
       (is_null ||
        instr->value()->CanComputeIsInstanceOf(instr->type(), &is_instance))) {
     Definition* result = new ConstantInstr(Bool::ZoneHandle(Bool::Get(
         instr->negate_result() ? !is_instance : is_instance)));
     result->set_ssa_temp_index(flow_graph_->alloc_ssa_temp_index());
     result->InsertBefore(instr);
     // Replace uses and remove the current instruction via the iterator.
     instr->ReplaceUsesWith(result);
     ASSERT(current_iterator()->Current() == instr);
     current_iterator()->RemoveCurrentFromGraph();
     if (FLAG_trace_optimization) {
       OS::Print("Replacing v%"Pd" with v%"Pd"\n",
                 instr->ssa_temp_index(),
                 result->ssa_temp_index());
     }
 
     if (FLAG_trace_type_check_elimination) {
-      const String& name = String::Handle(Symbols::New("InstanceOf"));
       FlowGraphPrinter::PrintTypeCheck(parsed_function(),
                                        instr->token_pos(),
                                        instr->value(),
                                        instr->type(),
-                                       name,
+                                       Symbols::InstanceOf(),
                                        /* eliminated = */ true);
     }
   }
 }
 
 
 void FlowGraphTypePropagator::VisitGraphEntry(GraphEntryInstr* graph_entry) {
   // Visit incoming parameters.
   for (intptr_t i = 0; i < graph_entry->initial_definitions()->length(); i++) {
     ParameterInstr* param =
@@ skipping 1778 matching lines @@
 
   if (FLAG_trace_constant_propagation) {
     OS::Print("\n==== After constant propagation ====\n");
     FlowGraphPrinter printer(*graph_);
     printer.PrintBlocks();
   }
 }
 
 
 }  // namespace dart