[interpreter] Create custom call opcodes for specific argument counts

src/interpreter/bytecode-array-builder.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/interpreter/bytecode-array-builder.h"
 
 #include "src/globals.h"
 #include "src/interpreter/bytecode-array-writer.h"
 #include "src/interpreter/bytecode-dead-code-optimizer.h"
 #include "src/interpreter/bytecode-label.h"
@@ skipping 870 matching lines @@
 }
 
 BytecodeArrayBuilder& BytecodeArrayBuilder::Call(Register callable,
                                                  RegisterList args,
                                                  int feedback_slot,
                                                  Call::CallType call_type,
                                                  TailCallMode tail_call_mode) {
   if (tail_call_mode == TailCallMode::kDisallow) {
     if (call_type == Call::NAMED_PROPERTY_CALL ||
         call_type == Call::KEYED_PROPERTY_CALL) {
       OutputCallProperty(callable, args, args.register_count(), feedback_slot);

[rmcilroy, 2017/02/06 12:20:01]

Note - you aren't getting any benifit of these handlers for the case were we are
calling named / keyed properties since they end up calling CallProperty instead.
Maybe we could drop CallProperty bytecode for now and rework this so that we
pass whether the call is a property call or not to the bytecode graph builder
via some other mechanism (extra operand or some side-channel in the TFV?)  

     } else {
-      OutputCall(callable, args, args.register_count(), feedback_slot);
+      if (args.register_count() == 1) {
+        OutputCall0(callable, args[0], feedback_slot);
+      } else if (args.register_count() == 2) {
+        OutputCall1(callable, args[0], args[1], feedback_slot);
+      } else if (args.register_count() == 3) {
+        OutputCall2(callable, args[0], args[1], args[2], feedback_slot);
+      } else {
+        OutputCall(callable, args, args.register_count(), feedback_slot);
+      }
     }
   } else {
     DCHECK(tail_call_mode == TailCallMode::kAllow);
     OutputTailCall(callable, args, args.register_count(), feedback_slot);
   }
   return *this;
 }
 
 BytecodeArrayBuilder& BytecodeArrayBuilder::CallWithSpread(Register callable,
                                                            RegisterList args) {
@@ skipping 154 matching lines @@
     RegisterList reg_list) {
   DCHECK(RegisterListIsValid(reg_list));
   if (register_optimizer_)
     register_optimizer_->PrepareOutputRegisterList(reg_list);
   return static_cast<uint32_t>(reg_list.first_register().ToOperand());
 }
 
 }  // namespace interpreter
 }  // namespace internal
 }  // namespace v8