[turbofan] Introduce an ExternalPointer type.

src/compiler/common-node-cache.h

 // Copyright 2014 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_COMPILER_COMMON_NODE_CACHE_H_
 #define V8_COMPILER_COMMON_NODE_CACHE_H_
 
 #include "src/compiler/node-cache.h"
 
 namespace v8 {
@@ skipping 27 matching lines @@
     return float32_constants_.Find(zone(), bit_cast<int32_t>(value));
   }
 
   Node** FindFloat64Constant(double value) {
     // We canonicalize double constants at the bit representation level.
     return float64_constants_.Find(zone(), bit_cast<int64_t>(value));
   }
 
   Node** FindExternalConstant(ExternalReference value);
 
+  Node** FindPointerConstant(intptr_t value) {
+    return pointer_constants_.Find(zone(), value);
+  }
+
   Node** FindNumberConstant(double value) {
     // We canonicalize double constants at the bit representation level.
     return number_constants_.Find(zone(), bit_cast<int64_t>(value));
   }
 
   Node** FindHeapConstant(Handle<HeapObject> value);
 
   Node** FindRelocatableInt32Constant(int32_t value, RelocInfoMode rmode) {
     return relocatable_int32_constants_.Find(zone(),
                                              std::make_pair(value, rmode));
   }
 
   Node** FindRelocatableInt64Constant(int64_t value, RelocInfoMode rmode) {
     return relocatable_int64_constants_.Find(zone(),
                                              std::make_pair(value, rmode));
   }
 
   // Return all nodes from the cache.
   void GetCachedNodes(ZoneVector<Node*>* nodes);
 
   Zone* zone() const { return zone_; }
 
  private:
   Int32NodeCache int32_constants_;
   Int64NodeCache int64_constants_;
   Int32NodeCache float32_constants_;
   Int64NodeCache float64_constants_;
   IntPtrNodeCache external_constants_;
+  IntPtrNodeCache pointer_constants_;
   Int64NodeCache number_constants_;
   IntPtrNodeCache heap_constants_;
   RelocInt32NodeCache relocatable_int32_constants_;
   RelocInt64NodeCache relocatable_int64_constants_;
   Zone* const zone_;
 
   DISALLOW_COPY_AND_ASSIGN(CommonNodeCache);
 };
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_COMMON_NODE_CACHE_H_