Simplify Hydrogen code stubs with variable argument count

src/code-stubs.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 259 matching lines @@
 
   virtual Code::Kind GetCodeKind() const { return Code::STUB; }
 
  protected:
   // Generates the assembler code for the stub.
   virtual void Generate(MacroAssembler* masm) = 0;
 };
 
 
 enum StubFunctionMode { NOT_JS_FUNCTION_STUB_MODE, JS_FUNCTION_STUB_MODE };
-
+enum HandlerArgumentsMode { DONT_PASS_ARGUMENTS, PASS_ARGUMENTS };
 
 struct CodeStubInterfaceDescriptor {
   CodeStubInterfaceDescriptor();
   int register_param_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_;
   StubFunctionMode function_mode_;
   Register* register_params_;
+
   Address deoptimization_handler_;
+  HandlerArgumentsMode handler_arguments_mode_;
 
   int environment_length() const {
-    if (stack_parameter_count_.is_valid()) {
-      return register_param_count_ + 1;
-    }
     return register_param_count_;
   }
 
   bool initialized() const { return register_param_count_ >= 0; }
 
   void SetMissHandler(ExternalReference handler) {
     miss_handler_ = handler;
     has_miss_handler_ = true;
+    // Our miss handler infrastructure doesn't currently support
+    // variable stack parameter counts.
+    ASSERT(!stack_parameter_count_.is_valid());
   }
 
   ExternalReference miss_handler() {
     ASSERT(has_miss_handler_);
     return miss_handler_;
   }
 
   bool has_miss_handler() {
     return has_miss_handler_;
   }
 
+  Register GetParameterRegister(int index) {
+    return register_params_[index];
+  }
+
+  bool IsParameterCountRegister(int index) {
+    return GetParameterRegister(index).is(stack_parameter_count_);
+  }
+
+  int GetHandlerParameterCount() {
+    int params = environment_length();
+    if (handler_arguments_mode_ == PASS_ARGUMENTS) {
+      params += 1;
+    }
+    return params;
+  }
+
  private:
   ExternalReference miss_handler_;
   bool has_miss_handler_;
 };
 
-// A helper to make up for the fact that type Register is not fully
-// defined outside of the platform directories
-#define DESCRIPTOR_GET_PARAMETER_REGISTER(descriptor, index) \
-  ((index) == (descriptor)->register_param_count_)           \
-      ? (descriptor)->stack_parameter_count_                 \
-      : (descriptor)->register_params_[(index)]
-
 
 class HydrogenCodeStub : public CodeStub {
  public:
   enum InitializationState {
     UNINITIALIZED,
     INITIALIZED
   };
 
   explicit HydrogenCodeStub(InitializationState state = INITIALIZED) {
     is_uninitialized_ = (state == UNINITIALIZED);
@@ skipping 2068 matching lines @@
   int MinorKey() { return 0; }
 
   void Generate(MacroAssembler* masm);
 
   DISALLOW_COPY_AND_ASSIGN(ProfileEntryHookStub);
 };
 
 } }  // namespace v8::internal
 
 #endif  // V8_CODE_STUBS_H_