Replace string GNU Triples with llvm::Triple in MCAsmBackend subclasses and create*AsmBackend(). NFC.

Summary:
This continues the patch series to eliminate StringRef forms of GNU triples
from the internals of LLVM that began in r239036.

Reviewers: echristo, rafael

Reviewed By: rafael

Subscribers: rafael, llvm-commits, rengolin

Differential Revision: http://reviews.llvm.org/D10243

llvm-svn: 239464
diff --git a/llvm/lib/Target/Mips/MCTargetDesc/MipsAsmBackend.cpp b/llvm/lib/Target/Mips/MCTargetDesc/MipsAsmBackend.cpp
index d823ffc..5c746b2 100644
--- a/llvm/lib/Target/Mips/MCTargetDesc/MipsAsmBackend.cpp
+++ b/llvm/lib/Target/Mips/MCTargetDesc/MipsAsmBackend.cpp
@@ -417,32 +417,27 @@
 // MCAsmBackend
 MCAsmBackend *llvm::createMipsAsmBackendEL32(const Target &T,
                                              const MCRegisterInfo &MRI,
-                                             StringRef TT,
-                                             StringRef CPU) {
-  return new MipsAsmBackend(T, Triple(TT).getOS(),
-                            /*IsLittle*/true, /*Is64Bit*/false);
+                                             const Triple &TT, StringRef CPU) {
+  return new MipsAsmBackend(T, TT.getOS(), /*IsLittle*/ true,
+                            /*Is64Bit*/ false);
 }
 
 MCAsmBackend *llvm::createMipsAsmBackendEB32(const Target &T,
                                              const MCRegisterInfo &MRI,
-                                             StringRef TT,
-                                             StringRef CPU) {
-  return new MipsAsmBackend(T, Triple(TT).getOS(),
-                            /*IsLittle*/false, /*Is64Bit*/false);
+                                             const Triple &TT, StringRef CPU) {
+  return new MipsAsmBackend(T, TT.getOS(), /*IsLittle*/ false,
+                            /*Is64Bit*/ false);
 }
 
 MCAsmBackend *llvm::createMipsAsmBackendEL64(const Target &T,
                                              const MCRegisterInfo &MRI,
-                                             StringRef TT,
-                                             StringRef CPU) {
-  return new MipsAsmBackend(T, Triple(TT).getOS(),
-                            /*IsLittle*/true, /*Is64Bit*/true);
+                                             const Triple &TT, StringRef CPU) {
+  return new MipsAsmBackend(T, TT.getOS(), /*IsLittle*/ true, /*Is64Bit*/ true);
 }
 
 MCAsmBackend *llvm::createMipsAsmBackendEB64(const Target &T,
                                              const MCRegisterInfo &MRI,
-                                             StringRef TT,
-                                             StringRef CPU) {
-  return new MipsAsmBackend(T, Triple(TT).getOS(),
-                            /*IsLittle*/false, /*Is64Bit*/true);
+                                             const Triple &TT, StringRef CPU) {
+  return new MipsAsmBackend(T, TT.getOS(), /*IsLittle*/ false,
+                            /*Is64Bit*/ true);
 }