Fix has_constant_parameter_count() confusion in LReturn

src/x64/lithium-codegen-x64.cc

 // Copyright 2013 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/v8.h"
 
 #if V8_TARGET_ARCH_X64
 
 #include "src/base/bits.h"
 #include "src/code-factory.h"
@@ skipping 2804 matching lines @@
   int no_frame_start = -1;
   if (NeedsEagerFrame()) {
     __ movp(rsp, rbp);
     __ popq(rbp);
     no_frame_start = masm_->pc_offset();
   }
   if (instr->has_constant_parameter_count()) {
     __ Ret((ToInteger32(instr->constant_parameter_count()) + 1) * kPointerSize,
            rcx);
   } else {
+    DCHECK(info()->IsStub());  // Functions would need to drop one more value.
     Register reg = ToRegister(instr->parameter_count());
     // The argument count parameter is a smi
     __ SmiToInteger32(reg, reg);
     Register return_addr_reg = reg.is(rcx) ? rbx : rcx;
     __ PopReturnAddressTo(return_addr_reg);
     __ shlp(reg, Immediate(kPointerSizeLog2));
     __ addp(rsp, reg);
     __ jmp(return_addr_reg);
   }
   if (no_frame_start != -1) {
@@ skipping 3047 matching lines @@
   CallRuntime(Runtime::kPushBlockContext, 2, instr);
   RecordSafepoint(Safepoint::kNoLazyDeopt);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal
 
 #endif  // V8_TARGET_ARCH_X64