Improve constant pool implementation in the assembler.

runtime/vm/assembler_mips.h

 // 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.
 
 #ifndef VM_ASSEMBLER_MIPS_H_
 #define VM_ASSEMBLER_MIPS_H_
 
 #ifndef VM_ASSEMBLER_H_
 #error Do not include assembler_mips.h directly; use assembler.h instead.
 #endif
 
 #include "platform/assert.h"
 #include "platform/utils.h"
 #include "vm/constants_mips.h"
+#include "vm/hash_map.h"
 #include "vm/object.h"
 #include "vm/simulator.h"
 
 // References to documentation in this file refer to:
 // "MIPS® Architecture For Programmers Volume I-A:
 //   Introduction to the MIPS32® Architecture" in short "VolI-A"
 // and
 // "MIPS® Architecture For Programmers Volume II-A:
 //   The MIPS32® Instruction Set" in short "VolII-A"
 namespace dart {
@@ skipping 1581 matching lines @@
   bool allow_constant_pool() const {
     return allow_constant_pool_;
   }
   void set_allow_constant_pool(bool b) {
     allow_constant_pool_ = b;
   }
 
  private:
   AssemblerBuffer buffer_;
   GrowableObjectArray& object_pool_;  // Objects and patchable jump targets.
+
+  // Hashmap for fast lookup in object pool.
+  DirectChainedHashMap<ObjIndexPair> object_pool_index_table_;
+
   intptr_t prologue_offset_;
 
   bool use_far_branches_;
   bool delay_slot_available_;
   bool in_delay_slot_;
 
   int32_t AddObject(const Object& obj);
   int32_t AddExternalLabel(const ExternalLabel* label);
 
   class CodeComment : public ZoneAllocated {
@@ skipping 114 matching lines @@
                                   Register value,
                                   Label* no_update);
 
   DISALLOW_ALLOCATION();
   DISALLOW_COPY_AND_ASSIGN(Assembler);
 };
 
 }  // namespace dart
 
 #endif  // VM_ASSEMBLER_MIPS_H_