[turbofan] Remove the function reload hack for OSR.

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/ast/scopes.h"
 #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"
@@ skipping 327 matching lines @@
   // Add JavaScript call argument count.
   locations.AddParam(regloc(kJavaScriptCallArgCountRegister));
   types.AddParam(MachineType::Int32());
 
   // Add context.
   locations.AddParam(regloc(kContextRegister));
   types.AddParam(MachineType::AnyTagged());
 
   // The target for JS function calls is the JSFunction object.
   MachineType target_type = MachineType::AnyTagged();
-  // TODO(titzer): When entering into an OSR function from unoptimized code,
-  // the JSFunction is not in a register, but it is on the stack in an
-  // unaddressable spill slot. We hack this in the OSR prologue. Fix.
-  LinkageLocation target_loc = regloc(kJSFunctionRegister);
+  // When entering into an OSR function from unoptimized code the JSFunction
+  // is not in a register, but it is on the stack in the marker spill slot.
+  LinkageLocation target_loc = is_osr ? LinkageLocation::ForSavedCallerMarker()
+                                      : regloc(kJSFunctionRegister);
   return new (zone) CallDescriptor(     // --
       CallDescriptor::kCallJSFunction,  // kind
       target_type,                      // target MachineType
       target_loc,                       // target location
       types.Build(),                    // machine_sig
       locations.Build(),                // location_sig
       js_parameter_count,               // stack_parameter_count
       Operator::kNoProperties,          // properties
       kNoCalleeSaved,                   // callee-saved
       kNoCalleeSaved,                   // callee-saved fp
@@ skipping 112 matching lines @@
   } else {
     DCHECK(loc == regloc(kContextRegister));
     return LinkageLocation::ForCalleeFrameSlot(Frame::kContextSlot);
   }
 }
 
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8