Simplify Hydrogen code stubs with variable argument count

src/x64/code-stubs-x64.cc

 // Copyright 2013 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 158 matching lines @@
 
 
 static void InitializeArrayConstructorDescriptor(
     Isolate* isolate,
     CodeStubInterfaceDescriptor* descriptor,
     int constant_stack_parameter_count) {
   // register state
   // rax -- number of arguments
   // rdi -- function
   // rbx -- type info cell with elements kind
-  static Register registers[] = { rdi, rbx };
-  descriptor->register_param_count_ = 2;
-  if (constant_stack_parameter_count != 0) {
+  static Register registers_variable_args[] = { rdi, rbx, rax };
+  static Register registers_no_args[] = { rdi, rbx };
+
+  if (constant_stack_parameter_count == 0) {
+    descriptor->register_param_count_ = 2;
+    descriptor->register_params_ = registers_no_args;
+  } else {
     // stack param count needs (constructor pointer, and single argument)
+    descriptor->handler_arguments_mode_ = PASS_ARGUMENTS;
     descriptor->stack_parameter_count_ = rax;
+    descriptor->register_param_count_ = 3;
+    descriptor->register_params_ = registers_variable_args;
   }
+
   descriptor->hint_stack_parameter_count_ = constant_stack_parameter_count;
-  descriptor->register_params_ = registers;
   descriptor->function_mode_ = JS_FUNCTION_STUB_MODE;
   descriptor->deoptimization_handler_ =
       Runtime::FunctionForId(Runtime::kArrayConstructor)->entry;
 }
 
 
 static void InitializeInternalArrayConstructorDescriptor(
     Isolate* isolate,
     CodeStubInterfaceDescriptor* descriptor,
     int constant_stack_parameter_count) {
   // register state
   // rax -- number of arguments
   // rdi -- constructor function
-  static Register registers[] = { rdi };
-  descriptor->register_param_count_ = 1;
+  static Register registers_variable_args[] = { rdi, rax };
+  static Register registers_no_args[] = { rdi };
 
-  if (constant_stack_parameter_count != 0) {
+  if (constant_stack_parameter_count == 0) {
+    descriptor->register_param_count_ = 1;
+    descriptor->register_params_ = registers_no_args;
+  } else {
     // stack param count needs (constructor pointer, and single argument)
+    descriptor->handler_arguments_mode_ = PASS_ARGUMENTS;
     descriptor->stack_parameter_count_ = rax;
+    descriptor->register_param_count_ = 2;
+    descriptor->register_params_ = registers_variable_args;
   }
+
   descriptor->hint_stack_parameter_count_ = constant_stack_parameter_count;
-  descriptor->register_params_ = registers;
   descriptor->function_mode_ = JS_FUNCTION_STUB_MODE;
   descriptor->deoptimization_handler_ =
       Runtime::FunctionForId(Runtime::kInternalArrayConstructor)->entry;
 }
 
 
 void ArrayNoArgumentConstructorStub::InitializeInterfaceDescriptor(
     Isolate* isolate,
     CodeStubInterfaceDescriptor* descriptor) {
   InitializeArrayConstructorDescriptor(isolate, descriptor, 0);
@@ skipping 5603 matching lines @@
   __ bind(&fast_elements_case);
   GenerateCase(masm, FAST_ELEMENTS);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64