[interpreter] Use hashmap for ConstantArrayBuilder's constant map

src/interpreter/constant-array-builder.h

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_INTERPRETER_CONSTANT_ARRAY_BUILDER_H_
 #define V8_INTERPRETER_CONSTANT_ARRAY_BUILDER_H_
 
 #include "src/identity-map.h"
 #include "src/interpreter/bytecodes.h"
 #include "src/zone/zone-containers.h"
@@ skipping 52 matching lines @@
   // Commit reserved entry and returns the constant pool index for the
   // SMI value.
   size_t CommitReservedEntry(OperandSize operand_size, Smi* value);
 
   // Discards constant pool reservation.
   void DiscardReservedEntry(OperandSize operand_size);
 
  private:
   typedef uint32_t index_t;
 
-  index_t AllocateEntry(Handle<Object> object);
   index_t AllocateIndex(Handle<Object> object);
   index_t AllocateReservedEntry(Smi* value);
 
   struct ConstantArraySlice final : public ZoneObject {
     ConstantArraySlice(Zone* zone, size_t start_index, size_t capacity,
                        OperandSize operand_size);
     void Reserve();
     void Unreserve();
     size_t Allocate(Handle<Object> object);
     Handle<Object> At(size_t index) const;
@@ skipping 17 matching lines @@
 
     DISALLOW_COPY_AND_ASSIGN(ConstantArraySlice);
   };
 
   ConstantArraySlice* IndexToSlice(size_t index) const;
   ConstantArraySlice* OperandSizeToSlice(OperandSize operand_size) const;
 
   Handle<Object> the_hole_value() const { return the_hole_value_; }
 
   ConstantArraySlice* idx_slice_[3];
-  ZoneMap<Address, index_t> constants_map_;
+  base::TemplateHashMapImpl<Address, index_t, std::equal_to<Address>,
+                            ZoneAllocationPolicy>
+      constants_map_;
   ZoneMap<Smi*, index_t> smi_map_;
   ZoneVector<std::pair<Smi*, index_t>> smi_pairs_;
+  Zone* zone_;
   Handle<Object> the_hole_value_;
 };
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_INTERPRETER_CONSTANT_ARRAY_BUILDER_H_