[turbofan] Enable tail calls for %_CallFunction.

src/compiler/mips/code-generator-mips.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/compiler/code-generator.h"
 #include "src/compiler/code-generator-impl.h"
 #include "src/compiler/gap-resolver.h"
 #include "src/compiler/node-matchers.h"
 #include "src/mips/macro-assembler-mips.h"
 #include "src/scopes.h"
@@ skipping 381 matching lines @@
     __ bind(ool->exit());                                                      \
     __ bind(&done);                                                            \
   } while (0)
 
 
 void CodeGenerator::AssembleDeconstructActivationRecord() {
   CallDescriptor* descriptor = linkage()->GetIncomingDescriptor();
   int stack_slots = frame()->GetSpillSlotCount();
   if (descriptor->IsJSFunctionCall() || stack_slots > 0) {
     __ LeaveFrame(StackFrame::MANUAL);
-    int pop_count = descriptor->IsJSFunctionCall()
-                        ? static_cast<int>(descriptor->JSParameterCount())
-                        : 0;
-    __ Drop(pop_count);
   }
 }
 
 
 // Assembles an instruction after register allocation, producing machine code.
 void CodeGenerator::AssembleArchInstruction(Instruction* instr) {
   MipsOperandConverter i(this, instr);
   InstructionCode opcode = instr->opcode();
 
   switch (ArchOpcodeField::decode(opcode)) {
@@ skipping 734 matching lines @@
   } else if (descriptor->IsJSFunctionCall() || needs_frame_) {
     // Canonicalize JSFunction return sites for now.
     if (return_label_.is_bound()) {
       __ Branch(&return_label_);
     } else {
       __ bind(&return_label_);
       __ mov(sp, fp);
       __ Pop(ra, fp);
       int pop_count = descriptor->IsJSFunctionCall()
                           ? static_cast<int>(descriptor->JSParameterCount())
-                          : 0;
-      __ DropAndRet(pop_count);
+                          : (info()->IsStub()
+                                 ? info()->code_stub()->GetStackParameterCount()
+                                 : 0);
+      if (pop_count != 0) {
+        __ DropAndRet(pop_count);
+      } else {
+        __ Ret();
+      }
     }
   } else {
     __ Ret();
   }
 }
 
 
 void CodeGenerator::AssembleMove(InstructionOperand* source,
                                  InstructionOperand* destination) {
   MipsOperandConverter g(this, NULL);
@@ skipping 198 matching lines @@
       }
     }
   }
 }
 
 #undef __
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8