Make stack_parameter_count a plain register.

src/code-stubs.h

Index: src/code-stubs.h
diff --git a/src/code-stubs.h b/src/code-stubs.h
index d2101ae293b6cee60ef3ca597bc483ab9b4d18ba..b5f74b26af25731faecbb6c72c91c522f6debf25 100644
--- a/src/code-stubs.h
+++ b/src/code-stubs.h
@@ -30,8 +30,9 @@
 
 #include "allocation.h"
 #include "assembler.h"
-#include "globals.h"
 #include "codegen.h"
+#include "globals.h"
+#include "macro-assembler.h"
 
 namespace v8 {
 namespace internal {
@@ -280,7 +281,7 @@ enum StubFunctionMode { NOT_JS_FUNCTION_STUB_MODE, JS_FUNCTION_STUB_MODE };
 struct CodeStubInterfaceDescriptor {
   CodeStubInterfaceDescriptor();
   int register_param_count_;
-  const Register* stack_parameter_count_;
+  Register stack_parameter_count_;
   // if hint_stack_parameter_count_ > 0, the code stub can optimize the
   // return sequence. Default value is -1, which means it is ignored.
   int hint_stack_parameter_count_;
@@ -289,7 +290,7 @@ struct CodeStubInterfaceDescriptor {
   Address deoptimization_handler_;
 
   int environment_length() const {
-    if (stack_parameter_count_ != NULL) {
+    if (stack_parameter_count_.is_valid()) {
       return register_param_count_ + 1;
     }
     return register_param_count_;
@@ -320,7 +321,7 @@ struct CodeStubInterfaceDescriptor {
 // defined outside of the platform directories
 #define DESCRIPTOR_GET_PARAMETER_REGISTER(descriptor, index) \
   ((index) == (descriptor)->register_param_count_)           \
-      ? *((descriptor)->stack_parameter_count_)              \
+      ? (descriptor)->stack_parameter_count_                 \
       : (descriptor)->register_params_[(index)]