Rework CallApi*Stubs.

src/compiler/fast-accessor-assembler.cc

 // Copyright 2015 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/fast-accessor-assembler.h"
 
 #include "src/base/logging.h"
-#include "src/code-stubs.h"  // For CallApiFunctionStub.
+#include "src/code-stubs.h"  // For CallApiCallbackStub.
 #include "src/compiler/graph.h"
 #include "src/compiler/linkage.h"
 #include "src/compiler/pipeline.h"
 #include "src/compiler/raw-machine-assembler.h"
 #include "src/compiler/schedule.h"
 #include "src/compiler/verifier.h"
 #include "src/handles-inl.h"
 #include "src/objects.h"  // For FAA::GetInternalField impl.
 
 namespace v8 {
@@ skipping 146 matching lines @@
       assembler_->IntPtrEqual(FromId(value_id), assembler_->IntPtrConstant(0)),
       &pass, FromId(label_id));
   assembler_->Bind(&pass);
 }
 
 FastAccessorAssembler::ValueId FastAccessorAssembler::Call(
     FunctionCallback callback_function, ValueId arg) {
   CHECK_EQ(kBuilding, state_);
 
   // Create API function stub.
-  CallApiFunctionStub stub(assembler_->isolate(), true);
+  CallApiCallbackStub stub(assembler_->isolate(), 1, true);
+  DCHECK_EQ(1, stub.GetCallInterfaceDescriptor().GetStackParameterCount());
 
   // Wrap the FunctionCallback in an ExternalReference.
   ApiFunction callback_api_function(FUNCTION_ADDR(callback_function));
   ExternalReference callback(&callback_api_function,
                              ExternalReference::DIRECT_API_CALL,
                              assembler_->isolate());
 
-  // The stub has 5 parameters, and kJSParam (here: 1) parameters to pass
-  // through to the callback.
-  // See: ApiFunctionDescriptor::BuildCallInterfaceDescriptorFunctionType
-  static const int kStackParam = 1;
+  // The stub has 6 parameters.
+  // See: ApiCallbackDescriptorBase::BuildCallInterfaceDescriptorFunctionType
   Node* args[] = {
       // Stub/register parameters:
-      assembler_->Parameter(0),                /* receiver (use accessor's) */
-      assembler_->UndefinedConstant(),         /* call_data (undefined) */
-      assembler_->NullConstant(),              /* holder (null) */
-      assembler_->ExternalConstant(callback),  /* API callback function */
-      assembler_->IntPtrConstant(kStackParam), /* # JS arguments */
+      assembler_->Parameter(0),               /* receiver (use accessor's) */
+      assembler_->UndefinedConstant(),        /* call_data (undefined) */
+      assembler_->NullConstant(),             /* holder (null) */
+      assembler_->ExternalConstant(callback), /* API callback function */
 
-      // kStackParam stack parameter(s):
+      // JS arguments, on stack:
       FromId(arg),
 
       // Context parameter. (See Linkage::GetStubCallDescriptor.)
       assembler_->UndefinedConstant()};

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

It might be slightly more efficient to pass Smi(0) here.

[vogelheim, 2016/03/09 11:09:35]

Ack. But: The point of this CL is to enable moving FastAccessorAssembler out of
compiler/ and from CallN to CallStub. That will also give me the chance to fix
the Context properly - it shouldn't be 0 / Undefined anyhow - so this will be
removed anyhow in the follow-on CL.

-  CHECK_EQ(5 + kStackParam + 1, arraysize(args));
+  DCHECK_EQ(arraysize(args),
+            1 + stub.GetCallInterfaceDescriptor().GetParameterCount());
 
   Node* call = assembler_->CallN(
       Linkage::GetStubCallDescriptor(
           assembler_->isolate(), zone(), stub.GetCallInterfaceDescriptor(),
-          kStackParam + stub.GetStackParameterCount(),
-          CallDescriptor::kNoFlags),
+          stub.GetStackParameterCount(), CallDescriptor::kNoFlags),
       assembler_->HeapConstant(stub.GetCode()), args);
   return FromRaw(call);
 }
 
 MaybeHandle<Code> FastAccessorAssembler::Build() {
   CHECK_EQ(kBuilding, state_);
 
   // Cleanup: We no longer need this.
   nodes_.clear();
   labels_.clear();
@@ skipping 36 matching lines @@
 RawMachineLabel* FastAccessorAssembler::FromId(LabelId label) const {
   CHECK_LT(label.label_id, labels_.size());
   CHECK_NOT_NULL(labels_.at(label.label_id));
   return labels_.at(label.label_id);
 }
 
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8