[turbofan] Add basic support for calling to (a subset of) C functions.

src/compiler/mips/linkage-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/assembler.h"
 #include "src/code-stubs.h"
 #include "src/compiler/linkage.h"
 #include "src/compiler/linkage-impl.h"
 #include "src/zone.h"
 
@@ skipping 10 matching lines @@
   static Register RuntimeCallArgCountReg() { return a0; }
   static RegList CCalleeSaveRegisters() {
     return s0.bit() | s1.bit() | s2.bit() | s3.bit() | s4.bit() | s5.bit() |
            s6.bit() | s7.bit();
   }
   static Register CRegisterParameter(int i) {
     static Register register_parameters[] = {a0, a1, a2, a3};
     return register_parameters[i];
   }
   static int CRegisterParametersLength() { return 4; }
+  static int CStackBackingStoreLength() { return 0; }
 };
 
 
 typedef LinkageHelper<MipsLinkageHelperTraits> LH;
 
 CallDescriptor* Linkage::GetJSCallDescriptor(Zone* zone, bool is_osr,
                                              int parameter_count,
                                              CallDescriptor::Flags flags) {
   return LH::GetJSCallDescriptor(zone, is_osr, parameter_count, flags);
 }
@@ skipping 18 matching lines @@
 
 
 CallDescriptor* Linkage::GetSimplifiedCDescriptor(Zone* zone,
                                                   const MachineSignature* sig) {
   return LH::GetSimplifiedCDescriptor(zone, sig);
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8