[turbofan]: Implement tail calls with more callee than caller parameters

src/compiler/linkage.cc

 // Copyright 2014 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/code-stubs.h"
 #include "src/compiler.h"
 #include "src/compiler/common-operator.h"
 #include "src/compiler/frame.h"
 #include "src/compiler/linkage.h"
 #include "src/compiler/node.h"
@@ skipping 73 matching lines @@
   if (ReturnCount() != other->ReturnCount()) return false;
   for (size_t i = 0; i < ReturnCount(); ++i) {
     if (GetReturnLocation(i) != other->GetReturnLocation(i)) return false;
   }
   return true;
 }
 
 
 bool CallDescriptor::CanTailCall(const Node* node,
                                  int* stack_param_delta) const {
-  // TODO(danno): TF only current supports tail calls where the number of stack
-  // parameters of the callee is the same or fewer of the caller.
   CallDescriptor const* other = OpParameter<CallDescriptor const*>(node);
-  if (!HasSameReturnLocationsAs(other)) return false;
   size_t current_input = 0;
   size_t other_input = 0;
   *stack_param_delta = 0;
   bool more_other = true;
   bool more_this = true;
   while (more_other || more_this) {
     if (other_input < other->InputCount()) {
       if (!other->GetInputLocation(other_input).IsRegister()) {
-        (*stack_param_delta)++;
+        (*stack_param_delta)--;
       }
     } else {
       more_other = false;
     }
     if (current_input < InputCount()) {
       if (!GetInputLocation(current_input).IsRegister()) {
-        (*stack_param_delta)--;
+        (*stack_param_delta)++;
       }
     } else {
       more_this = false;
     }
     ++current_input;
     ++other_input;
   }
-  return *stack_param_delta <= 0;
+  return HasSameReturnLocationsAs(OpParameter<CallDescriptor const*>(node));
 }
 
 
 CallDescriptor* Linkage::ComputeIncoming(Zone* zone, CompilationInfo* info) {
   if (info->code_stub() != NULL) {
     // Use the code stub interface descriptor.
     CodeStub* stub = info->code_stub();
     CallInterfaceDescriptor descriptor = stub->GetCallInterfaceDescriptor();
     return GetStubCallDescriptor(
         info->isolate(), zone, descriptor, stub->GetStackParameterCount(),
@@ skipping 408 matching lines @@
   } else {
     DCHECK(loc == regloc(kContextRegister));
     return LinkageLocation::ForCalleeFrameSlot(Frame::kContextSlot);
   }
 }
 
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8