Fix clobbered register when setting this_function variable.

src/x64/full-codegen-x64.cc

 // Copyright 2012 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/code-factory.h"
 #include "src/code-stubs.h"
@@ skipping 217 matching lines @@
         }
       }
     }
   }
 
   // Possibly set up a local binding to the this function which is used in
   // derived constructors with super calls.
   Variable* this_function_var = scope()->this_function_var();
   if (this_function_var != nullptr) {
     Comment cmnt(masm_, "[ This function");
+    if (!function_in_register) {
+      __ movp(rdi, Operand(rbp, JavaScriptFrameConstants::kFunctionOffset));
+      function_in_register = true;
+    }
     SetVar(this_function_var, rdi, rbx, rdx);
   }
 
   Variable* new_target_var = scope()->new_target_var();
   if (new_target_var != nullptr) {
     Comment cmnt(masm_, "[ new.target");
     // new.target is parameter -2.
     int offset = 2 * kPointerSize + kFPOnStackSize + kPCOnStackSize +
                  (info_->scope()->num_parameters() - 1) * kPointerSize;
     __ movp(rax, Operand(rbp, offset));
@@ skipping 5233 matching lines @@
             Assembler::target_address_at(call_target_address,
                                          unoptimized_code));
   return OSR_AFTER_STACK_CHECK;
 }
 
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_TARGET_ARCH_X64