[Driver][Darwin] Use T reference instead of getToolChain().getTriple().

[vsk]

Thanks, lgtm.

clang/lib/Driver/ToolChains/Darwin.cpp

void darwin::setTripleTypeForMachOArchName(llvm::Triple &T, StringRef Str) {
   }
 }
 
 void darwin::Assembler::ConstructJob(Compilation &C, const JobAction &JA,
                                      const InputInfo &Output,
                                      const InputInfoList &Inputs,
                                      const ArgList &Args,
                                      const char *LinkingOutput) const {
+  const llvm::Triple &T(getToolChain().getTriple());
+
   ArgStringList CmdArgs;
 
   assert(Inputs.size() == 1 && "Unexpected number of inputs.");
   const InputInfo &Input = Inputs[0];
 
   // Determine the original source input.
   const Action *SourceAction = &JA;
   while (SourceAction->getKind() != Action::InputClass) {
     assert(!SourceAction->getInputs().empty() && "unexpected root action!");
     SourceAction = SourceAction->getInputs()[0];
   }
 
   // If -fno-integrated-as is used add -Q to the darwin assembler driver to make
   // sure it runs its system assembler not clang's integrated assembler.
   // Applicable to darwin11+ and Xcode 4+.  darwin<10 lacked integrated-as.
   // FIXME: at run-time detect assembler capabilities or rely on version
   // information forwarded by -target-assembler-version.
   if (Args.hasArg(options::OPT_fno_integrated_as)) {
-    const llvm::Triple &T(getToolChain().getTriple());
     if (!(T.isMacOSX() && T.isMacOSXVersionLT(10, 7)))
       CmdArgs.push_back("-Q");
   }
 
   // Forward -g, assuming we are dealing with an actual assembly file.
   if (SourceAction->getType() == types::TY_Asm ||
       SourceAction->getType() == types::TY_PP_Asm) {
     if (Args.hasArg(options::OPT_gstabs))
       CmdArgs.push_back("--gstabs");
     else if (Args.hasArg(options::OPT_g_Group))
       CmdArgs.push_back("-g");
   }
 
   // Derived from asm spec.
   AddMachOArch(Args, CmdArgs);
 
   // Use -force_cpusubtype_ALL on x86 by default.
-  if (getToolChain().getTriple().isX86() ||
-      Args.hasArg(options::OPT_force__cpusubtype__ALL))
+  if (T.isX86() || Args.hasArg(options::OPT_force__cpusubtype__ALL))
     CmdArgs.push_back("-force_cpusubtype_ALL");
 
   if (getToolChain().getArch() != llvm::Triple::x86_64 &&
       (((Args.hasArg(options::OPT_mkernel) ||
          Args.hasArg(options::OPT_fapple_kext)) &&
         getMachOToolChain().isKernelStatic()) ||
        Args.hasArg(options::OPT_static)))
     CmdArgs.push_back("-static");