[crankshaft] Support ES6 tail call elimination.

src/mips/macro-assembler-mips.h

Index: src/mips/macro-assembler-mips.h
diff --git a/src/mips/macro-assembler-mips.h b/src/mips/macro-assembler-mips.h
index e92eb9ec4ebf95260a631e64bca45b49754a97cc..a04548ca6cb35dbbc40b0336c933ab35dc147265 100644
--- a/src/mips/macro-assembler-mips.h
+++ b/src/mips/macro-assembler-mips.h
@@ -982,8 +982,16 @@ class MacroAssembler: public Assembler {
   // -------------------------------------------------------------------------
   // JavaScript invokes.
 
-  // Invoke the JavaScript function code by either calling or jumping.
+  // Removes current frame and its arguments from the stack preserving
+  // the arguments and a return address pushed to the stack for the next call.
+  // 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.
+  void PrepareForTailCall(const ParameterCount& callee_args_count,
+                          Register caller_args_count_reg, Register scratch0,
+                          Register scratch1);
 
+  // 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,