[turbofan] Introduce an ExternalPointer type.

src/compiler/js-create-lowering.cc

 // Copyright 2016 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.
 
 #include "src/compiler/js-create-lowering.h"
 
 #include "src/allocation-site-scopes.h"
 #include "src/code-factory.h"
 #include "src/compilation-dependencies.h"
 #include "src/compiler/access-builder.h"
@@ skipping 656 matching lines @@
 
   Node* effect = NodeProperties::GetEffectInput(node);
   Node* control = NodeProperties::GetControlInput(node);
   Node* context = NodeProperties::GetContextInput(node);
   int const function_map_index =
       Context::FunctionMapIndex(shared->language_mode(), shared->kind());
   Node* function_map = jsgraph()->HeapConstant(
       handle(Map::cast(native_context()->get(function_map_index)), isolate()));
   // Note that it is only safe to embed the raw entry point of the compile
   // lazy stub into the code, because that stub is immortal and immovable.
-  Node* compile_entry = jsgraph()->IntPtrConstant(reinterpret_cast<intptr_t>(
-      jsgraph()->isolate()->builtins()->CompileLazy()->entry()));
+  Node* compile_entry = jsgraph()->PointerConstant(
+      jsgraph()->isolate()->builtins()->CompileLazy()->entry());
   Node* empty_fixed_array = jsgraph()->EmptyFixedArrayConstant();
   Node* empty_literals_array = jsgraph()->EmptyLiteralsArrayConstant();
   Node* the_hole = jsgraph()->TheHoleConstant();
   Node* undefined = jsgraph()->UndefinedConstant();
   AllocationBuilder a(jsgraph(), effect, control);
   STATIC_ASSERT(JSFunction::kSize == 9 * kPointerSize);
   a.Allocate(JSFunction::kSize, p.pretenure());
   a.Store(AccessBuilder::ForMap(), function_map);
   a.Store(AccessBuilder::ForJSObjectProperties(), empty_fixed_array);
   a.Store(AccessBuilder::ForJSObjectElements(), empty_fixed_array);
@@ skipping 563 matching lines @@
   return jsgraph()->simplified();
 }
 
 MachineOperatorBuilder* JSCreateLowering::machine() const {
   return jsgraph()->machine();
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8