X87: [turbofan] Further fixing ES6 tail call elimination in Turbofan.

src/x87/macro-assembler-x87.h

 // 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.
 
 #ifndef V8_X87_MACRO_ASSEMBLER_X87_H_
 #define V8_X87_MACRO_ASSEMBLER_X87_H_
 
 #include "src/assembler.h"
 #include "src/bailout-reason.h"
 #include "src/frames.h"
@@ skipping 307 matching lines @@
   void LoadWeakValue(Register value, Handle<WeakCell> cell, Label* miss);
 
   // ---------------------------------------------------------------------------
   // JavaScript invokes
 
   // Removes current frame and its arguments from the stack preserving
   // the arguments and a return address pushed to the stack for the next call.
   // |ra_state| defines whether return address is already pushed to stack or
   // not. Both |callee_args_count| and |caller_args_count_reg| do not include
   // receiver. |callee_args_count| is not modified, |caller_args_count_reg|
-  // is trashed.
+  // is trashed. |number_of_temp_values_after_return_address| specifies
+  // the number of words pushed to the stack after the return address. This is
+  // to allow "allocation" of scratch registers that this function requires
+  // by saving their values on the stack.
   void PrepareForTailCall(const ParameterCount& callee_args_count,
                           Register caller_args_count_reg, Register scratch0,
-                          Register scratch1, ReturnAddressState ra_state);
+                          Register scratch1, ReturnAddressState ra_state,
+                          int number_of_temp_values_after_return_address);
 
   // Invoke the JavaScript function code by either calling or jumping.
 
   void InvokeFunctionCode(Register function, Register new_target,
                           const ParameterCount& expected,
                           const ParameterCount& actual, InvokeFlag flag,
                           const CallWrapper& call_wrapper);
 
   void FloodFunctionIfStepping(Register fun, Register new_target,
                                const ParameterCount& expected,
@@ skipping 672 matching lines @@
   }                                                                       \
   masm->
 #else
 #define ACCESS_MASM(masm) masm->
 #endif
 
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_X87_MACRO_ASSEMBLER_X87_H_