Const-corrected some MachineSignature* parameters.

src/compiler/linkage-impl.h

 // 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.
 
 #ifndef V8_COMPILER_LINKAGE_IMPL_H_
 #define V8_COMPILER_LINKAGE_IMPL_H_
 
 #include "src/code-stubs.h"
 #include "src/compiler/osr.h"
 
@@ skipping 174 matching lines @@
         target_loc,                       // target location
         types.Build(),                    // machine_sig
         locations.Build(),                // location_sig
         js_parameter_count,               // js_parameter_count
         properties,                       // properties
         kNoCalleeSaved,                   // callee-saved registers
         flags,                            // flags
         descriptor.DebugName(isolate));
   }
 
-  static CallDescriptor* GetSimplifiedCDescriptor(Zone* zone,
-                                                  MachineSignature* msig) {
+  static CallDescriptor* GetSimplifiedCDescriptor(
+      Zone* zone, const MachineSignature* msig) {
     LocationSignature::Builder locations(zone, msig->return_count(),
                                          msig->parameter_count());
     // Add return location(s).
     AddReturnLocations(&locations);
 
     // Add register and/or stack parameter(s).
     const int parameter_count = static_cast<int>(msig->parameter_count());
     for (int i = 0; i < parameter_count; i++) {
       if (i < LinkageTraits::CRegisterParametersLength()) {
         locations.AddParam(regloc(LinkageTraits::CRegisterParameter(i)));
@@ skipping 46 matching lines @@
     return incoming_->GetInputLocation(parameter_index);
   }
 }
 
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8
 
 #endif  // V8_COMPILER_LINKAGE_IMPL_H_