[turbofan] Fix loading of JSFunction from activation in case of adapter frame.

src/compiler/linkage-impl.h

 // 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.
 
 #ifndef V8_COMPILER_LINKAGE_IMPL_H_
 #define V8_COMPILER_LINKAGE_IMPL_H_
 
 #include "src/code-stubs.h"
 #include "src/compiler/osr.h"
 
@@ skipping 39 matching lines @@
       int spill_slot_index = i - js_parameter_count;
       locations.AddParam(stackloc(spill_slot_index));
       types.AddParam(kMachAnyTagged);
     }
     // Add context.
     locations.AddParam(regloc(LinkageTraits::ContextReg()));
     types.AddParam(kMachAnyTagged);
 
     // The target for JS function calls is the JSFunction object.
     MachineType target_type = kMachAnyTagged;
-    // Unoptimized code doesn't preserve the JSCallFunctionReg, so expect the
-    // closure on the stack.
-    LinkageLocation target_loc =
-        is_osr ? stackloc(Linkage::kJSFunctionCallClosureParamIndex -
-                          js_parameter_count)
-               : regloc(LinkageTraits::JSCallFunctionReg());
+    // TODO(titzer): JSFunction is in the frame, but not currently addressable.

[Michael Starzinger, 2015/03/25 14:27:37]

nit: IIUC this TODO only applies to OSR, for non-OSR it is totally fine to
always use the register and let the register allocator spill it for us. Can we
please add that to the sentence to avoid future confusion.

[titzer, 2015/03/25 16:12:05]

Done.

+    LinkageLocation target_loc = regloc(LinkageTraits::JSCallFunctionReg());
     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,               // js_parameter_count
         Operator::kNoProperties,          // properties
         kNoCalleeSaved,                   // callee-saved
         flags,                            // flags
@@ skipping 209 matching lines @@
     int parameter_index = 1 + index;  // skip index 0, which is the target.
     return incoming_->GetInputLocation(parameter_index);
   }
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_LINKAGE_IMPL_H_