[turbofan] Better and more sane support for tail calls

src/compiler/linkage.h

Index: src/compiler/linkage.h
diff --git a/src/compiler/linkage.h b/src/compiler/linkage.h
index 0f4b8db1c448055bc4568d5673bbf0b26a53fce5..04b6e98202c38014244ddbf6026257b830222fd3 100644
--- a/src/compiler/linkage.h
+++ b/src/compiler/linkage.h
@@ -57,6 +57,15 @@ class LinkageLocation {
     return LinkageLocation(STACK_SLOT, slot);
   }
 
+  static LinkageLocation ConvertToTailCallerLocation(
+      LinkageLocation caller_location, int stack_param_delta) {
+    if (!caller_location.IsRegister()) {
+      return LinkageLocation(STACK_SLOT,
+                             caller_location.GetLocation() + stack_param_delta);
+    }
+    return caller_location;
+  }
+
  private:
   friend class CallDescriptor;
   friend class OperandGenerator;
@@ -222,7 +231,7 @@ class CallDescriptor final : public ZoneObject {
 
   bool HasSameReturnLocationsAs(const CallDescriptor* other) const;
 
-  bool CanTailCall(const Node* call) const;
+  bool CanTailCall(const Node* call, int* stack_param_delta) const;
 
  private:
   friend class Linkage;