Rework CallApi*Stubs.

src/interface-descriptors.cc

 // Copyright 2012 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/interface-descriptors.h"
 
 namespace v8 {
 namespace internal {
 
 namespace {
@@ skipping 476 matching lines @@
   Zone* zone = isolate->interface_descriptor_zone();
   FunctionType* function =
       Type::Function(AnyTagged(zone), Type::Undefined(), 4, zone)->AsFunction();
   function->InitParameter(0, Type::Receiver());          // JSFunction
   function->InitParameter(1, AnyTagged(zone));           // the new target
   function->InitParameter(2, UntaggedIntegral32(zone));  // actual #arguments
   function->InitParameter(3, UntaggedIntegral32(zone));  // expected #arguments
   return function;
 }
 
-FunctionType* ApiFunctionDescriptor::BuildCallInterfaceDescriptorFunctionType(
-    Isolate* isolate, int paramater_count) {
-  Zone* zone = isolate->interface_descriptor_zone();
-  FunctionType* function =
-      Type::Function(AnyTagged(zone), Type::Undefined(), 5, zone)->AsFunction();
-  function->InitParameter(0, AnyTagged(zone));           // callee
-  function->InitParameter(1, AnyTagged(zone));           // call_data
-  function->InitParameter(2, AnyTagged(zone));           // holder
-  function->InitParameter(3, ExternalPointer(zone));     // api_function_address
-  function->InitParameter(4, UntaggedIntegral32(zone));  // actual #arguments
-  return function;
+CallInterfaceDescriptor ApiCallbackDescriptorBase::ForArgs(Isolate* isolate,
+                                                           int argc) {
+  switch (argc) {
+    case 0:
+      return ApiCallbackWith0ArgsDescriptor(isolate);
+    case 1:
+      return ApiCallbackWith1ArgsDescriptor(isolate);
+    case 2:
+      return ApiCallbackWith2ArgsDescriptor(isolate);
+    case 3:
+      return ApiCallbackWith3ArgsDescriptor(isolate);
+    case 4:
+      return ApiCallbackWith4ArgsDescriptor(isolate);
+    case 5:
+      return ApiCallbackWith5ArgsDescriptor(isolate);
+    case 6:
+      return ApiCallbackWith6ArgsDescriptor(isolate);
+    case 7:
+      return ApiCallbackWith7ArgsDescriptor(isolate);

[danno, 2016/03/04 18:07:42]

Shouldn't you have a default case that is also unreachable? Don't know what the
compiler would do in the case that you pass "8".

[vogelheim, 2016/03/08 12:59:27]

Done.

I'm honestly a bit confused at this feedback, though. With argc == 8, the switch
should have just fall through and reach the UNREACHABLE.

[danno, 2016/03/09 10:23:38]

I looked at the C/C++ spec, and you're right. Without a default, it just falls
through, so feel free to go back to what you had.

+  }
+  UNREACHABLE();
 }
 
-FunctionType* ApiAccessorDescriptor::BuildCallInterfaceDescriptorFunctionType(
-    Isolate* isolate, int paramater_count) {
+FunctionType* BuildFunctionTypeForCallback(Isolate* isolate,
+                                           int accessor_parameter_count) {
   Zone* zone = isolate->interface_descriptor_zone();
-  FunctionType* function =
-      Type::Function(AnyTagged(zone), Type::Undefined(), 4, zone)->AsFunction();
+  FunctionType* function = Type::Function(AnyTagged(zone), Type::Undefined(),
+                                          4 + accessor_parameter_count, zone)
+                               ->AsFunction();
   function->InitParameter(0, AnyTagged(zone));        // callee
   function->InitParameter(1, AnyTagged(zone));        // call_data
   function->InitParameter(2, AnyTagged(zone));        // holder
   function->InitParameter(3, ExternalPointer(zone));  // api_function_address
+  for (int i = 0; i < accessor_parameter_count; i++) {
+    function->InitParameter(i, AnyTagged(zone));
+  }
   return function;
 }
 
+template <int argc>
+FunctionType*
+ApiCallbackWithArgsBase<argc>::BuildCallInterfaceDescriptorFunctionType(
+    Isolate* isolate, int parameter_count) {
+  return BuildFunctionTypeForCallback(isolate, argc);
+}
+
+template class ApiCallbackWithArgsBase<0>;
+template class ApiCallbackWithArgsBase<1>;
+template class ApiCallbackWithArgsBase<2>;
+template class ApiCallbackWithArgsBase<3>;
+template class ApiCallbackWithArgsBase<4>;
+template class ApiCallbackWithArgsBase<5>;
+template class ApiCallbackWithArgsBase<6>;
+template class ApiCallbackWithArgsBase<7>;
+
 FunctionType*
 InterpreterDispatchDescriptor::BuildCallInterfaceDescriptorFunctionType(
     Isolate* isolate, int parameter_count) {
   Zone* zone = isolate->interface_descriptor_zone();
   FunctionType* function =
       Type::Function(AnyTagged(zone), Type::Undefined(), 5, zone)->AsFunction();
   function->InitParameter(kAccumulatorParameter, AnyTagged(zone));
   function->InitParameter(kRegisterFileParameter, ExternalPointer(zone));
   function->InitParameter(kBytecodeOffsetParameter, UntaggedIntegral32(zone));
   function->InitParameter(kBytecodeArrayParameter, AnyTagged(zone));
   function->InitParameter(kDispatchTableParameter, AnyTagged(zone));
   return function;
 }
 
 }  // namespace internal
 }  // namespace v8