Thread MCSubtargetInfo through Target::createMCAsmBackend

Currently it's not possible to access MCSubtargetInfo from a TgtMCAsmBackend. 
D20830 threaded an MCSubtargetInfo reference through 
MCAsmBackend::relaxInstruction, but this isn't the only function that would 
benefit from access. This patch removes the Triple and CPUString arguments 
from createMCAsmBackend and replaces them with MCSubtargetInfo.

This patch just changes the interface without making any intentional 
functional changes. Once in, several cleanups are possible:
* Get rid of the awkward MCSubtargetInfo handling in ARMAsmBackend
* Support 16-bit instructions when valid in MipsAsmBackend::writeNopData
* Get rid of the CPU string parsing in X86AsmBackend and just use a SubtargetFeature for HasNopl
* Emit 16-bit nops in RISCVAsmBackend::writeNopData if the compressed instruction set extension is enabled (see D41221)

This change initially exposed PR35686, which has since been resolved in r321026.

Differential Revision: https://reviews.llvm.org/D41349

llvm-svn: 321692

30 files changed, 116 insertions, 101 deletions

diff --git a/llvm/include/llvm/Support/TargetRegistry.h b/llvm/include/llvm/Support/TargetRegistry.h
index bd096e2f74f..cc0d55722c8 100644
--- a/llvm/include/llvm/Support/TargetRegistry.h
+++ b/llvm/include/llvm/Support/TargetRegistry.h
@@ -123,8 +123,8 @@ public:
   using AsmPrinterCtorTy = AsmPrinter *(*)(
       TargetMachine &TM, std::unique_ptr<MCStreamer> &&Streamer);
   using MCAsmBackendCtorTy = MCAsmBackend *(*)(const Target &T,
+                                               const MCSubtargetInfo &STI,
                                                const MCRegisterInfo &MRI,
-                                               const Triple &TT, StringRef CPU,
                                                const MCTargetOptions &Options);
   using MCAsmParserCtorTy = MCTargetAsmParser *(*)(
       const MCSubtargetInfo &STI, MCAsmParser &P, const MCInstrInfo &MII,
@@ -383,13 +383,12 @@ public:
   /// createMCAsmBackend - Create a target specific assembly parser.
   ///
   /// \param TheTriple The target triple string.
-  MCAsmBackend *createMCAsmBackend(const MCRegisterInfo &MRI,
-                                   StringRef TheTriple, StringRef CPU,
-                                   const MCTargetOptions &Options)
-                                   const {
+  MCAsmBackend *createMCAsmBackend(const MCSubtargetInfo &STI,
+                                   const MCRegisterInfo &MRI,
+                                   const MCTargetOptions &Options) const {
     if (!MCAsmBackendCtorFn)
       return nullptr;
-    return MCAsmBackendCtorFn(*this, MRI, Triple(TheTriple), CPU, Options);
+    return MCAsmBackendCtorFn(*this, STI, MRI, Options);
   }
 
   /// createMCAsmParser - Create a target specific assembly parser.
@@ -1106,10 +1105,10 @@ template <class MCAsmBackendImpl> struct RegisterMCAsmBackend {
   }
 
 private:
-  static MCAsmBackend *Allocator(const Target &T, const MCRegisterInfo &MRI,
-                                 const Triple &TheTriple, StringRef CPU,
+  static MCAsmBackend *Allocator(const Target &T, const MCSubtargetInfo &STI,
+                                 const MCRegisterInfo &MRI,
                                  const MCTargetOptions &Options) {
-    return new MCAsmBackendImpl(T, MRI, TheTriple, CPU);
+    return new MCAsmBackendImpl(T, STI, MRI);
   }
 };
 
diff --git a/llvm/lib/CodeGen/LLVMTargetMachine.cpp b/llvm/lib/CodeGen/LLVMTargetMachine.cpp
index 77a7aaa9573..4c6e21ab315 100644
--- a/llvm/lib/CodeGen/LLVMTargetMachine.cpp
+++ b/llvm/lib/CodeGen/LLVMTargetMachine.cpp
@@ -136,8 +136,7 @@ bool LLVMTargetMachine::addAsmPrinter(PassManagerBase &PM,
       MCE = getTarget().createMCCodeEmitter(MII, MRI, Context);
 
     MCAsmBackend *MAB =
-        getTarget().createMCAsmBackend(MRI, getTargetTriple().str(), TargetCPU,
-                                       Options.MCOptions);
+        getTarget().createMCAsmBackend(STI, MRI, Options.MCOptions);
     auto FOut = llvm::make_unique<formatted_raw_ostream>(Out);
     MCStreamer *S = getTarget().createAsmStreamer(
         Context, std::move(FOut), Options.MCOptions.AsmVerbose,
@@ -151,8 +150,7 @@ bool LLVMTargetMachine::addAsmPrinter(PassManagerBase &PM,
     // emission fails.
     MCCodeEmitter *MCE = getTarget().createMCCodeEmitter(MII, MRI, Context);
     MCAsmBackend *MAB =
-        getTarget().createMCAsmBackend(MRI, getTargetTriple().str(), TargetCPU,
-                                       Options.MCOptions);
+        getTarget().createMCAsmBackend(STI, MRI, Options.MCOptions);
     if (!MCE || !MAB)
       return true;
 
@@ -225,17 +223,16 @@ bool LLVMTargetMachine::addPassesToEmitMC(PassManagerBase &PM, MCContext *&Ctx,
 
   // Create the code emitter for the target if it exists.  If not, .o file
   // emission fails.
+  const MCSubtargetInfo &STI = *getMCSubtargetInfo();
   const MCRegisterInfo &MRI = *getMCRegisterInfo();
   MCCodeEmitter *MCE =
       getTarget().createMCCodeEmitter(*getMCInstrInfo(), MRI, *Ctx);
   MCAsmBackend *MAB =
-      getTarget().createMCAsmBackend(MRI, getTargetTriple().str(), TargetCPU,
-                                     Options.MCOptions);
+      getTarget().createMCAsmBackend(STI, MRI, Options.MCOptions);
   if (!MCE || !MAB)
     return true;
 
   const Triple &T = getTargetTriple();
-  const MCSubtargetInfo &STI = *getMCSubtargetInfo();
   std::unique_ptr<MCStreamer> AsmStreamer(getTarget().createMCObjectStreamer(
       T, *Ctx, std::unique_ptr<MCAsmBackend>(MAB), Out,
       std::unique_ptr<MCCodeEmitter>(MCE), STI, Options.MCOptions.MCRelaxAll,
diff --git a/llvm/lib/Target/AArch64/MCTargetDesc/AArch64AsmBackend.cpp b/llvm/lib/Target/AArch64/MCTargetDesc/AArch64AsmBackend.cpp
index 7b33b4b5b54..4d1d3fd5735 100644
--- a/llvm/lib/Target/AArch64/MCTargetDesc/AArch64AsmBackend.cpp
+++ b/llvm/lib/Target/AArch64/MCTargetDesc/AArch64AsmBackend.cpp
@@ -605,10 +605,10 @@ public:
 }
 
 MCAsmBackend *llvm::createAArch64leAsmBackend(const Target &T,
+                                              const MCSubtargetInfo &STI,
                                               const MCRegisterInfo &MRI,
-                                              const Triple &TheTriple,
-                                              StringRef CPU,
                                               const MCTargetOptions &Options) {
+  const Triple &TheTriple = STI.getTargetTriple();
   if (TheTriple.isOSBinFormatMachO())
     return new DarwinAArch64AsmBackend(T, TheTriple, MRI);
 
@@ -624,10 +624,10 @@ MCAsmBackend *llvm::createAArch64leAsmBackend(const Target &T,
 }
 
 MCAsmBackend *llvm::createAArch64beAsmBackend(const Target &T,
+                                              const MCSubtargetInfo &STI,
                                               const MCRegisterInfo &MRI,
-                                              const Triple &TheTriple,
-                                              StringRef CPU,
                                               const MCTargetOptions &Options) {
+  const Triple &TheTriple = STI.getTargetTriple();
   assert(TheTriple.isOSBinFormatELF() &&
          "Big endian is only supported for ELF targets!");
   uint8_t OSABI = MCELFObjectTargetWriter::getOSABI(TheTriple.getOS());
diff --git a/llvm/lib/Target/AArch64/MCTargetDesc/AArch64MCTargetDesc.h b/llvm/lib/Target/AArch64/MCTargetDesc/AArch64MCTargetDesc.h
index b9e1673b931..a5720e0e8b8 100644
--- a/llvm/lib/Target/AArch64/MCTargetDesc/AArch64MCTargetDesc.h
+++ b/llvm/lib/Target/AArch64/MCTargetDesc/AArch64MCTargetDesc.h
@@ -45,12 +45,12 @@ MCCodeEmitter *createAArch64MCCodeEmitter(const MCInstrInfo &MCII,
                                           const MCRegisterInfo &MRI,
                                           MCContext &Ctx);
 MCAsmBackend *createAArch64leAsmBackend(const Target &T,
+                                        const MCSubtargetInfo &STI,
                                         const MCRegisterInfo &MRI,
-                                        const Triple &TT, StringRef CPU,
                                         const MCTargetOptions &Options);
 MCAsmBackend *createAArch64beAsmBackend(const Target &T,
+                                        const MCSubtargetInfo &STI,
                                         const MCRegisterInfo &MRI,
-                                        const Triple &TT, StringRef CPU,
                                         const MCTargetOptions &Options);
 
 std::unique_ptr<MCObjectWriter>
diff --git a/llvm/lib/Target/AMDGPU/MCTargetDesc/AMDGPUAsmBackend.cpp b/llvm/lib/Target/AMDGPU/MCTargetDesc/AMDGPUAsmBackend.cpp
index 778d4a7ba9d..d700acc34bc 100644
--- a/llvm/lib/Target/AMDGPU/MCTargetDesc/AMDGPUAsmBackend.cpp
+++ b/llvm/lib/Target/AMDGPU/MCTargetDesc/AMDGPUAsmBackend.cpp
@@ -198,9 +198,9 @@ public:
 } // end anonymous namespace
 
 MCAsmBackend *llvm::createAMDGPUAsmBackend(const Target &T,
+                                           const MCSubtargetInfo &STI,
                                            const MCRegisterInfo &MRI,
-                                           const Triple &TT, StringRef CPU,
                                            const MCTargetOptions &Options) {
   // Use 64-bit ELF for amdgcn
-  return new ELFAMDGPUAsmBackend(T, TT);
+  return new ELFAMDGPUAsmBackend(T, STI.getTargetTriple());
 }
diff --git a/llvm/lib/Target/AMDGPU/MCTargetDesc/AMDGPUMCTargetDesc.h b/llvm/lib/Target/AMDGPU/MCTargetDesc/AMDGPUMCTargetDesc.h
index 0b3563303ad..1173dfd437c 100644
--- a/llvm/lib/Target/AMDGPU/MCTargetDesc/AMDGPUMCTargetDesc.h
+++ b/llvm/lib/Target/AMDGPU/MCTargetDesc/AMDGPUMCTargetDesc.h
@@ -45,8 +45,9 @@ MCCodeEmitter *createSIMCCodeEmitter(const MCInstrInfo &MCII,
                                      const MCRegisterInfo &MRI,
                                      MCContext &Ctx);
 
-MCAsmBackend *createAMDGPUAsmBackend(const Target &T, const MCRegisterInfo &MRI,
-                                     const Triple &TT, StringRef CPU,
+MCAsmBackend *createAMDGPUAsmBackend(const Target &T,
+                                     const MCSubtargetInfo &STI,
+                                     const MCRegisterInfo &MRI,
                                      const MCTargetOptions &Options);
 
 std::unique_ptr<MCObjectWriter>
diff --git a/llvm/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp b/llvm/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp
index 1cb9dd44f78..8552e62b652 100644
--- a/llvm/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp
+++ b/llvm/lib/Target/ARM/MCTargetDesc/ARMAsmBackend.cpp
@@ -1176,29 +1176,33 @@ MCAsmBackend *llvm::createARMAsmBackend(const Target &T,
 }
 
 MCAsmBackend *llvm::createARMLEAsmBackend(const Target &T,
+                                          const MCSubtargetInfo &STI,
                                           const MCRegisterInfo &MRI,
-                                          const Triple &TT, StringRef CPU,
                                           const MCTargetOptions &Options) {
-  return createARMAsmBackend(T, MRI, TT, CPU, Options, true);
+  return createARMAsmBackend(T, MRI, STI.getTargetTriple(), STI.getCPU(),
+                             Options, true);
 }
 
 MCAsmBackend *llvm::createARMBEAsmBackend(const Target &T,
+                                          const MCSubtargetInfo &STI,
                                           const MCRegisterInfo &MRI,
-                                          const Triple &TT, StringRef CPU,
                                           const MCTargetOptions &Options) {
-  return createARMAsmBackend(T, MRI, TT, CPU, Options, false);
+  return createARMAsmBackend(T, MRI, STI.getTargetTriple(), STI.getCPU(),
+                             Options, false);
 }
 
 MCAsmBackend *llvm::createThumbLEAsmBackend(const Target &T,
+                                            const MCSubtargetInfo &STI,
                                             const MCRegisterInfo &MRI,
-                                            const Triple &TT, StringRef CPU,
                                             const MCTargetOptions &Options) {
-  return createARMAsmBackend(T, MRI, TT, CPU, Options, true);
+  return createARMAsmBackend(T, MRI, STI.getTargetTriple(), STI.getCPU(),
+                             Options, true);
 }
 
 MCAsmBackend *llvm::createThumbBEAsmBackend(const Target &T,
+                                            const MCSubtargetInfo &STI,
                                             const MCRegisterInfo &MRI,
-                                            const Triple &TT, StringRef CPU,
                                             const MCTargetOptions &Options) {
-  return createARMAsmBackend(T, MRI, TT, CPU, Options, false);
+  return createARMAsmBackend(T, MRI, STI.getTargetTriple(), STI.getCPU(),
+                             Options, false);
 }
diff --git a/llvm/lib/Target/ARM/MCTargetDesc/ARMMCTargetDesc.h b/llvm/lib/Target/ARM/MCTargetDesc/ARMMCTargetDesc.h
index 0fb97e5fee9..7ef72846368 100644
--- a/llvm/lib/Target/ARM/MCTargetDesc/ARMMCTargetDesc.h
+++ b/llvm/lib/Target/ARM/MCTargetDesc/ARMMCTargetDesc.h
@@ -73,22 +73,22 @@ MCAsmBackend *createARMAsmBackend(const Target &T, const MCRegisterInfo &MRI,
                                   const MCTargetOptions &Options,
                                   bool IsLittleEndian);
 
-MCAsmBackend *createARMLEAsmBackend(const Target &T, const MCRegisterInfo &MRI,
-                                    const Triple &TT, StringRef CPU,
+MCAsmBackend *createARMLEAsmBackend(const Target &T, const MCSubtargetInfo &STI,
+                                    const MCRegisterInfo &MRI,
                                     const MCTargetOptions &Options);
 
-MCAsmBackend *createARMBEAsmBackend(const Target &T, const MCRegisterInfo &MRI,
-                                    const Triple &TT, StringRef CPU,
+MCAsmBackend *createARMBEAsmBackend(const Target &T, const MCSubtargetInfo &STI,
+                                    const MCRegisterInfo &MRI,
                                     const MCTargetOptions &Options);
 
 MCAsmBackend *createThumbLEAsmBackend(const Target &T,
+                                      const MCSubtargetInfo &STI,
                                       const MCRegisterInfo &MRI,
-                                      const Triple &TT, StringRef CPU,
                                       const MCTargetOptions &Options);
 
 MCAsmBackend *createThumbBEAsmBackend(const Target &T,
+                                      const MCSubtargetInfo &STI,
                                       const MCRegisterInfo &MRI,
-                                      const Triple &TT, StringRef CPU,
                                       const MCTargetOptions &Options);
 
 // Construct a PE/COFF machine code streamer which will generate a PE/COFF
diff --git a/llvm/lib/Target/BPF/MCTargetDesc/BPFAsmBackend.cpp b/llvm/lib/Target/BPF/MCTargetDesc/BPFAsmBackend.cpp
index e6ea92e0836..6593d9d018f 100644
--- a/llvm/lib/Target/BPF/MCTargetDesc/BPFAsmBackend.cpp
+++ b/llvm/lib/Target/BPF/MCTargetDesc/BPFAsmBackend.cpp
@@ -104,15 +104,15 @@ BPFAsmBackend::createObjectWriter(raw_pwrite_stream &OS) const {
 }
 
 MCAsmBackend *llvm::createBPFAsmBackend(const Target &T,
+                                        const MCSubtargetInfo &STI,
                                         const MCRegisterInfo &MRI,
-                                        const Triple &TT, StringRef CPU,
-                                        const MCTargetOptions&) {
+                                        const MCTargetOptions &) {
   return new BPFAsmBackend(/*IsLittleEndian=*/true);
 }
 
 MCAsmBackend *llvm::createBPFbeAsmBackend(const Target &T,
+                                          const MCSubtargetInfo &STI,
                                           const MCRegisterInfo &MRI,
-                                          const Triple &TT, StringRef CPU,
-                                          const MCTargetOptions&) {
+                                          const MCTargetOptions &) {
   return new BPFAsmBackend(/*IsLittleEndian=*/false);
 }
diff --git a/llvm/lib/Target/BPF/MCTargetDesc/BPFMCTargetDesc.h b/llvm/lib/Target/BPF/MCTargetDesc/BPFMCTargetDesc.h
index 6466042f692..a6dac3abca0 100644
--- a/llvm/lib/Target/BPF/MCTargetDesc/BPFMCTargetDesc.h
+++ b/llvm/lib/Target/BPF/MCTargetDesc/BPFMCTargetDesc.h
@@ -45,11 +45,11 @@ MCCodeEmitter *createBPFbeMCCodeEmitter(const MCInstrInfo &MCII,
                                         const MCRegisterInfo &MRI,
                                         MCContext &Ctx);
 
-MCAsmBackend *createBPFAsmBackend(const Target &T, const MCRegisterInfo &MRI,
-                                  const Triple &TT, StringRef CPU,
+MCAsmBackend *createBPFAsmBackend(const Target &T, const MCSubtargetInfo &STI,
+                                  const MCRegisterInfo &MRI,
                                   const MCTargetOptions &Options);
-MCAsmBackend *createBPFbeAsmBackend(const Target &T, const MCRegisterInfo &MRI,
-                                    const Triple &TT, StringRef CPU,
+MCAsmBackend *createBPFbeAsmBackend(const Target &T, const MCSubtargetInfo &STI,
+                                    const MCRegisterInfo &MRI,
                                     const MCTargetOptions &Options);
 
 std::unique_ptr<MCObjectWriter> createBPFELFObjectWriter(raw_pwrite_stream &OS,
diff --git a/llvm/lib/Target/Hexagon/MCTargetDesc/HexagonAsmBackend.cpp b/llvm/lib/Target/Hexagon/MCTargetDesc/HexagonAsmBackend.cpp
index b3ab6763281..fe54c19370b 100644
--- a/llvm/lib/Target/Hexagon/MCTargetDesc/HexagonAsmBackend.cpp
+++ b/llvm/lib/Target/Hexagon/MCTargetDesc/HexagonAsmBackend.cpp
@@ -765,11 +765,12 @@ public:
 
 // MCAsmBackend
 MCAsmBackend *llvm::createHexagonAsmBackend(Target const &T,
-                                      MCRegisterInfo const & /*MRI*/,
-                                      const Triple &TT, StringRef CPU,
-                                      const MCTargetOptions &Options) {
+                                            const MCSubtargetInfo &STI,
+                                            MCRegisterInfo const & /*MRI*/,
+                                            const MCTargetOptions &Options) {
+  const Triple &TT = STI.getTargetTriple();
   uint8_t OSABI = MCELFObjectTargetWriter::getOSABI(TT.getOS());
 
-  StringRef CPUString = Hexagon_MC::selectHexagonCPU(CPU);
+  StringRef CPUString = Hexagon_MC::selectHexagonCPU(STI.getCPU());
   return new HexagonAsmBackend(T, TT, OSABI, CPUString);
 }
diff --git a/llvm/lib/Target/Hexagon/MCTargetDesc/HexagonMCTargetDesc.h b/llvm/lib/Target/Hexagon/MCTargetDesc/HexagonMCTargetDesc.h
index 05d17c368dc..71545a5c02c 100644
--- a/llvm/lib/Target/Hexagon/MCTargetDesc/HexagonMCTargetDesc.h
+++ b/llvm/lib/Target/Hexagon/MCTargetDesc/HexagonMCTargetDesc.h
@@ -61,8 +61,8 @@ MCCodeEmitter *createHexagonMCCodeEmitter(const MCInstrInfo &MCII,
                                           MCContext &MCT);
 
 MCAsmBackend *createHexagonAsmBackend(const Target &T,
+                                      const MCSubtargetInfo &STI,
                                       const MCRegisterInfo &MRI,
-                                      const Triple &TT, StringRef CPU,
                                       const MCTargetOptions &Options);
 
 std::unique_ptr<MCObjectWriter>
diff --git a/llvm/lib/Target/Lanai/MCTargetDesc/LanaiAsmBackend.cpp b/llvm/lib/Target/Lanai/MCTargetDesc/LanaiAsmBackend.cpp
index c4935746f5a..e3eaa4d30a9 100644
--- a/llvm/lib/Target/Lanai/MCTargetDesc/LanaiAsmBackend.cpp
+++ b/llvm/lib/Target/Lanai/MCTargetDesc/LanaiAsmBackend.cpp
@@ -165,9 +165,10 @@ LanaiAsmBackend::getFixupKindInfo(MCFixupKind Kind) const {
 } // namespace
 
 MCAsmBackend *llvm::createLanaiAsmBackend(const Target &T,
+                                          const MCSubtargetInfo &STI,
                                           const MCRegisterInfo & /*MRI*/,
-                                          const Triple &TT, StringRef /*CPU*/,
                                           const MCTargetOptions & /*Options*/) {
+  const Triple &TT = STI.getTargetTriple();
   if (!TT.isOSBinFormatELF())
     llvm_unreachable("OS not supported");
 
diff --git a/llvm/lib/Target/Lanai/MCTargetDesc/LanaiMCTargetDesc.h b/llvm/lib/Target/Lanai/MCTargetDesc/LanaiMCTargetDesc.h
index 5bc84ad8387..ddb4e9b0d72 100644
--- a/llvm/lib/Target/Lanai/MCTargetDesc/LanaiMCTargetDesc.h
+++ b/llvm/lib/Target/Lanai/MCTargetDesc/LanaiMCTargetDesc.h
@@ -38,8 +38,8 @@ MCCodeEmitter *createLanaiMCCodeEmitter(const MCInstrInfo &MCII,
                                         const MCRegisterInfo &MRI,
                                         MCContext &Ctx);
 
-MCAsmBackend *createLanaiAsmBackend(const Target &T, const MCRegisterInfo &MRI,
-                                    const Triple &TheTriple, StringRef CPU,
+MCAsmBackend *createLanaiAsmBackend(const Target &T, const MCSubtargetInfo &STI,
+                                    const MCRegisterInfo &MRI,
                                     const MCTargetOptions &Options);
 
 std::unique_ptr<MCObjectWriter>
diff --git a/llvm/lib/Target/Mips/MCTargetDesc/MipsAsmBackend.cpp b/llvm/lib/Target/Mips/MCTargetDesc/MipsAsmBackend.cpp
index 1ad524c0696..acbc6d37e24 100644
--- a/llvm/lib/Target/Mips/MCTargetDesc/MipsAsmBackend.cpp
+++ b/llvm/lib/Target/Mips/MCTargetDesc/MipsAsmBackend.cpp
@@ -476,8 +476,9 @@ bool MipsAsmBackend::writeNopData(uint64_t Count, MCObjectWriter *OW) const {
 }
 
 MCAsmBackend *llvm::createMipsAsmBackend(const Target &T,
+                                         const MCSubtargetInfo &STI,
                                          const MCRegisterInfo &MRI,
-                                         const Triple &TT, StringRef CPU,
                                          const MCTargetOptions &Options) {
-  return new MipsAsmBackend(T, MRI, TT, CPU, Options.ABIName == "n32");
+  return new MipsAsmBackend(T, MRI, STI.getTargetTriple(), STI.getCPU(),
+                            Options.ABIName == "n32");
 }
diff --git a/llvm/lib/Target/Mips/MCTargetDesc/MipsMCTargetDesc.h b/llvm/lib/Target/Mips/MCTargetDesc/MipsMCTargetDesc.h
index abbf08ed212..5dab6c3e81d 100644
--- a/llvm/lib/Target/Mips/MCTargetDesc/MipsMCTargetDesc.h
+++ b/llvm/lib/Target/Mips/MCTargetDesc/MipsMCTargetDesc.h
@@ -45,8 +45,8 @@ MCCodeEmitter *createMipsMCCodeEmitterEL(const MCInstrInfo &MCII,
                                          const MCRegisterInfo &MRI,
                                          MCContext &Ctx);
 
-MCAsmBackend *createMipsAsmBackend(const Target &T, const MCRegisterInfo &MRI,
-                                   const Triple &TT, StringRef CPU,
+MCAsmBackend *createMipsAsmBackend(const Target &T, const MCSubtargetInfo &STI,
+                                   const MCRegisterInfo &MRI,
                                    const MCTargetOptions &Options);
 
 std::unique_ptr<MCObjectWriter>
diff --git a/llvm/lib/Target/PowerPC/MCTargetDesc/PPCAsmBackend.cpp b/llvm/lib/Target/PowerPC/MCTargetDesc/PPCAsmBackend.cpp
index 2a1de244da9..728e7757fd2 100644
--- a/llvm/lib/Target/PowerPC/MCTargetDesc/PPCAsmBackend.cpp
+++ b/llvm/lib/Target/PowerPC/MCTargetDesc/PPCAsmBackend.cpp
@@ -18,6 +18,7 @@
 #include "llvm/MC/MCMachObjectWriter.h"
 #include "llvm/MC/MCObjectWriter.h"
 #include "llvm/MC/MCSectionMachO.h"
+#include "llvm/MC/MCSubtargetInfo.h"
 #include "llvm/MC/MCSymbolELF.h"
 #include "llvm/MC/MCValue.h"
 #include "llvm/Support/ErrorHandling.h"
@@ -231,9 +232,10 @@ namespace {
 } // end anonymous namespace
 
 MCAsmBackend *llvm::createPPCAsmBackend(const Target &T,
+                                        const MCSubtargetInfo &STI,
                                         const MCRegisterInfo &MRI,
-                                        const Triple &TT, StringRef CPU,
                                         const MCTargetOptions &Options) {
+  const Triple &TT = STI.getTargetTriple();
   if (TT.isOSDarwin())
     return new DarwinPPCAsmBackend(T);
 
diff --git a/llvm/lib/Target/PowerPC/MCTargetDesc/PPCMCTargetDesc.h b/llvm/lib/Target/PowerPC/MCTargetDesc/PPCMCTargetDesc.h
index 80a74c09a59..d47b9a6e452 100644
--- a/llvm/lib/Target/PowerPC/MCTargetDesc/PPCMCTargetDesc.h
+++ b/llvm/lib/Target/PowerPC/MCTargetDesc/PPCMCTargetDesc.h
@@ -29,6 +29,7 @@ class MCContext;
 class MCInstrInfo;
 class MCObjectWriter;
 class MCRegisterInfo;
+class MCSubtargetInfo;
 class MCTargetOptions;
 class Target;
 class Triple;
@@ -43,8 +44,8 @@ MCCodeEmitter *createPPCMCCodeEmitter(const MCInstrInfo &MCII,
                                       const MCRegisterInfo &MRI,
                                       MCContext &Ctx);
 
-MCAsmBackend *createPPCAsmBackend(const Target &T, const MCRegisterInfo &MRI,
-                                  const Triple &TT, StringRef CPU,
+MCAsmBackend *createPPCAsmBackend(const Target &T, const MCSubtargetInfo &STI,
+                                  const MCRegisterInfo &MRI,
                                   const MCTargetOptions &Options);
 
 /// Construct an PPC ELF object writer.
diff --git a/llvm/lib/Target/RISCV/MCTargetDesc/RISCVAsmBackend.cpp b/llvm/lib/Target/RISCV/MCTargetDesc/RISCVAsmBackend.cpp
index b91467fe145..6e06a4975e2 100644
--- a/llvm/lib/Target/RISCV/MCTargetDesc/RISCVAsmBackend.cpp
+++ b/llvm/lib/Target/RISCV/MCTargetDesc/RISCVAsmBackend.cpp
@@ -230,9 +230,10 @@ RISCVAsmBackend::createObjectWriter(raw_pwrite_stream &OS) const {
 } // end anonymous namespace
 
 MCAsmBackend *llvm::createRISCVAsmBackend(const Target &T,
+                                          const MCSubtargetInfo &STI,
                                           const MCRegisterInfo &MRI,
-                                          const Triple &TT, StringRef CPU,
                                           const MCTargetOptions &Options) {
+  const Triple &TT = STI.getTargetTriple();
   uint8_t OSABI = MCELFObjectTargetWriter::getOSABI(TT.getOS());
   return new RISCVAsmBackend(OSABI, TT.isArch64Bit());
 }
diff --git a/llvm/lib/Target/RISCV/MCTargetDesc/RISCVMCTargetDesc.h b/llvm/lib/Target/RISCV/MCTargetDesc/RISCVMCTargetDesc.h
index bea2f8800fa..ef58a6b8cbc 100644
--- a/llvm/lib/Target/RISCV/MCTargetDesc/RISCVMCTargetDesc.h
+++ b/llvm/lib/Target/RISCV/MCTargetDesc/RISCVMCTargetDesc.h
@@ -40,8 +40,8 @@ MCCodeEmitter *createRISCVMCCodeEmitter(const MCInstrInfo &MCII,
                                         const MCRegisterInfo &MRI,
                                         MCContext &Ctx);
 
-MCAsmBackend *createRISCVAsmBackend(const Target &T, const MCRegisterInfo &MRI,
-                                    const Triple &TT, StringRef CPU,
+MCAsmBackend *createRISCVAsmBackend(const Target &T, const MCSubtargetInfo &STI,
+                                    const MCRegisterInfo &MRI,
                                     const MCTargetOptions &Options);
 
 std::unique_ptr<MCObjectWriter>
diff --git a/llvm/lib/Target/Sparc/MCTargetDesc/SparcAsmBackend.cpp b/llvm/lib/Target/Sparc/MCTargetDesc/SparcAsmBackend.cpp
index a38545ecf43..f2438ee4307 100644
--- a/llvm/lib/Target/Sparc/MCTargetDesc/SparcAsmBackend.cpp
+++ b/llvm/lib/Target/Sparc/MCTargetDesc/SparcAsmBackend.cpp
@@ -14,6 +14,7 @@
 #include "llvm/MC/MCExpr.h"
 #include "llvm/MC/MCFixupKindInfo.h"
 #include "llvm/MC/MCObjectWriter.h"
+#include "llvm/MC/MCSubtargetInfo.h"
 #include "llvm/MC/MCValue.h"
 #include "llvm/Support/TargetRegistry.h"
 
@@ -301,8 +302,8 @@ namespace {
 } // end anonymous namespace
 
 MCAsmBackend *llvm::createSparcAsmBackend(const Target &T,
+                                          const MCSubtargetInfo &STI,
                                           const MCRegisterInfo &MRI,
-                                          const Triple &TT, StringRef CPU,
                                           const MCTargetOptions &Options) {
-  return new ELFSparcAsmBackend(T, TT.getOS());
+  return new ELFSparcAsmBackend(T, STI.getTargetTriple().getOS());
 }
diff --git a/llvm/lib/Target/Sparc/MCTargetDesc/SparcMCTargetDesc.h b/llvm/lib/Target/Sparc/MCTargetDesc/SparcMCTargetDesc.h
index 563e6f4efbe..8390198479b 100644
--- a/llvm/lib/Target/Sparc/MCTargetDesc/SparcMCTargetDesc.h
+++ b/llvm/lib/Target/Sparc/MCTargetDesc/SparcMCTargetDesc.h
@@ -40,8 +40,8 @@ Target &getTheSparcelTarget();
 MCCodeEmitter *createSparcMCCodeEmitter(const MCInstrInfo &MCII,
                                         const MCRegisterInfo &MRI,
                                         MCContext &Ctx);
-MCAsmBackend *createSparcAsmBackend(const Target &T, const MCRegisterInfo &MRI,
-                                    const Triple &TT, StringRef CPU,
+MCAsmBackend *createSparcAsmBackend(const Target &T, const MCSubtargetInfo &STI,
+                                    const MCRegisterInfo &MRI,
                                     const MCTargetOptions &Options);
 std::unique_ptr<MCObjectWriter>
 createSparcELFObjectWriter(raw_pwrite_stream &OS, bool Is64Bit,
diff --git a/llvm/lib/Target/SystemZ/MCTargetDesc/SystemZMCAsmBackend.cpp b/llvm/lib/Target/SystemZ/MCTargetDesc/SystemZMCAsmBackend.cpp
index e035c3b87a4..5cd4a7daf0f 100644
--- a/llvm/lib/Target/SystemZ/MCTargetDesc/SystemZMCAsmBackend.cpp
+++ b/llvm/lib/Target/SystemZ/MCTargetDesc/SystemZMCAsmBackend.cpp
@@ -14,6 +14,7 @@
 #include "llvm/MC/MCFixupKindInfo.h"
 #include "llvm/MC/MCInst.h"
 #include "llvm/MC/MCObjectWriter.h"
+#include "llvm/MC/MCSubtargetInfo.h"
 
 using namespace llvm;
 
@@ -122,9 +123,10 @@ bool SystemZMCAsmBackend::writeNopData(uint64_t Count,
 }
 
 MCAsmBackend *llvm::createSystemZMCAsmBackend(const Target &T,
+                                              const MCSubtargetInfo &STI,
                                               const MCRegisterInfo &MRI,
-                                              const Triple &TT, StringRef CPU,
                                               const MCTargetOptions &Options) {
-  uint8_t OSABI = MCELFObjectTargetWriter::getOSABI(TT.getOS());
+  uint8_t OSABI =
+      MCELFObjectTargetWriter::getOSABI(STI.getTargetTriple().getOS());
   return new SystemZMCAsmBackend(OSABI);
 }
diff --git a/llvm/lib/Target/SystemZ/MCTargetDesc/SystemZMCTargetDesc.h b/llvm/lib/Target/SystemZ/MCTargetDesc/SystemZMCTargetDesc.h
index 99b157e3727..ed1b1b95b8f 100644
--- a/llvm/lib/Target/SystemZ/MCTargetDesc/SystemZMCTargetDesc.h
+++ b/llvm/lib/Target/SystemZ/MCTargetDesc/SystemZMCTargetDesc.h
@@ -89,8 +89,8 @@ MCCodeEmitter *createSystemZMCCodeEmitter(const MCInstrInfo &MCII,
                                           MCContext &Ctx);
 
 MCAsmBackend *createSystemZMCAsmBackend(const Target &T,
+                                        const MCSubtargetInfo &STI,
                                         const MCRegisterInfo &MRI,
-                                        const Triple &TT, StringRef CPU,
                                         const MCTargetOptions &Options);
 
 std::unique_ptr<MCObjectWriter> createSystemZObjectWriter(raw_pwrite_stream &OS,
diff --git a/llvm/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp b/llvm/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp
index 239db2a74b2..717e2f44f56 100644
--- a/llvm/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp
+++ b/llvm/lib/Target/X86/MCTargetDesc/X86AsmBackend.cpp
@@ -843,10 +843,12 @@ public:
 } // end anonymous namespace
 
 MCAsmBackend *llvm::createX86_32AsmBackend(const Target &T,
+                                           const MCSubtargetInfo &STI,
                                            const MCRegisterInfo &MRI,
-                                           const Triple &TheTriple,
-                                           StringRef CPU,
                                            const MCTargetOptions &Options) {
+  const Triple &TheTriple = STI.getTargetTriple();
+  StringRef CPU = STI.getCPU();
+  llvm::errs() << "create x86-32 backend with CPU: " << CPU << "\n";
   if (TheTriple.isOSBinFormatMachO())
     return new DarwinX86_32AsmBackend(T, MRI, CPU);
 
@@ -862,10 +864,11 @@ MCAsmBackend *llvm::createX86_32AsmBackend(const Target &T,
 }
 
 MCAsmBackend *llvm::createX86_64AsmBackend(const Target &T,
+                                           const MCSubtargetInfo &STI,
                                            const MCRegisterInfo &MRI,
-                                           const Triple &TheTriple,
-                                           StringRef CPU,
                                            const MCTargetOptions &Options) {
+  const Triple &TheTriple = STI.getTargetTriple();
+  StringRef CPU = STI.getCPU();
   if (TheTriple.isOSBinFormatMachO()) {
     MachO::CPUSubTypeX86 CS =
         StringSwitch<MachO::CPUSubTypeX86>(TheTriple.getArchName())
diff --git a/llvm/lib/Target/X86/MCTargetDesc/X86MCTargetDesc.h b/llvm/lib/Target/X86/MCTargetDesc/X86MCTargetDesc.h
index c5859b600ad..d758c0588cb 100644
--- a/llvm/lib/Target/X86/MCTargetDesc/X86MCTargetDesc.h
+++ b/llvm/lib/Target/X86/MCTargetDesc/X86MCTargetDesc.h
@@ -70,11 +70,13 @@ MCCodeEmitter *createX86MCCodeEmitter(const MCInstrInfo &MCII,
                                       const MCRegisterInfo &MRI,
                                       MCContext &Ctx);
 
-MCAsmBackend *createX86_32AsmBackend(const Target &T, const MCRegisterInfo &MRI,
-                                     const Triple &TT, StringRef CPU,
+MCAsmBackend *createX86_32AsmBackend(const Target &T,
+                                     const MCSubtargetInfo &STI,
+                                     const MCRegisterInfo &MRI,
                                      const MCTargetOptions &Options);
-MCAsmBackend *createX86_64AsmBackend(const Target &T, const MCRegisterInfo &MRI,
-                                     const Triple &TT, StringRef CPU,
+MCAsmBackend *createX86_64AsmBackend(const Target &T,
+                                     const MCSubtargetInfo &STI,
+                                     const MCRegisterInfo &MRI,
                                      const MCTargetOptions &Options);
 
 /// Implements X86-only directives for assembly emission.
diff --git a/llvm/tools/dsymutil/DwarfLinker.cpp b/llvm/tools/dsymutil/DwarfLinker.cpp
index 50ffc69dfaa..0f5713b6b4f 100644
--- a/llvm/tools/dsymutil/DwarfLinker.cpp
+++ b/llvm/tools/dsymutil/DwarfLinker.cpp
@@ -672,8 +672,12 @@ bool DwarfStreamer::init(Triple TheTriple) {
   MC.reset(new MCContext(MAI.get(), MRI.get(), MOFI.get()));
   MOFI->InitMCObjectFileInfo(TheTriple, /*PIC*/ false, *MC);
 
+  MSTI.reset(TheTarget->createMCSubtargetInfo(TripleName, "", ""));
+  if (!MSTI)
+    return error("no subtarget info for target " + TripleName, Context);
+
   MCTargetOptions Options;
-  MAB = TheTarget->createMCAsmBackend(*MRI, TripleName, "", Options);
+  MAB = TheTarget->createMCAsmBackend(*MSTI, *MRI, Options);
   if (!MAB)
     return error("no asm backend for target " + TripleName, Context);
 
@@ -681,10 +685,6 @@ bool DwarfStreamer::init(Triple TheTriple) {
   if (!MII)
     return error("no instr info info for target " + TripleName, Context);
 
-  MSTI.reset(TheTarget->createMCSubtargetInfo(TripleName, "", ""));
-  if (!MSTI)
-    return error("no subtarget info for target " + TripleName, Context);
-
   MCE = TheTarget->createMCCodeEmitter(*MII, *MRI, *MC);
   if (!MCE)
     return error("no code emitter for target " + TripleName, Context);
diff --git a/llvm/tools/llvm-dwp/llvm-dwp.cpp b/llvm/tools/llvm-dwp/llvm-dwp.cpp
index dbbe61bf3b0..f577635473e 100644
--- a/llvm/tools/llvm-dwp/llvm-dwp.cpp
+++ b/llvm/tools/llvm-dwp/llvm-dwp.cpp
@@ -673,8 +673,13 @@ int main(int argc, char **argv) {
   MCContext MC(MAI.get(), MRI.get(), &MOFI);
   MOFI.InitMCObjectFileInfo(TheTriple, /*PIC*/ false, MC);
 
+  std::unique_ptr<MCSubtargetInfo> MSTI(
+      TheTarget->createMCSubtargetInfo(TripleName, "", ""));
+  if (!MSTI)
+    return error("no subtarget info for target " + TripleName, Context);
+
   MCTargetOptions Options;
-  auto MAB = TheTarget->createMCAsmBackend(*MRI, TripleName, "", Options);
+  auto MAB = TheTarget->createMCAsmBackend(*MSTI, *MRI, Options);
   if (!MAB)
     return error("no asm backend for target " + TripleName, Context);
 
@@ -682,11 +687,6 @@ int main(int argc, char **argv) {
   if (!MII)
     return error("no instr info info for target " + TripleName, Context);
 
-  std::unique_ptr<MCSubtargetInfo> MSTI(
-      TheTarget->createMCSubtargetInfo(TripleName, "", ""));
-  if (!MSTI)
-    return error("no subtarget info for target " + TripleName, Context);
-
   MCCodeEmitter *MCE = TheTarget->createMCCodeEmitter(*MII, *MRI, MC);
   if (!MCE)
     return error("no code emitter for target " + TripleName, Context);
diff --git a/llvm/tools/llvm-mc/llvm-mc.cpp b/llvm/tools/llvm-mc/llvm-mc.cpp
index e925346eb2d..3987be2bd68 100644
--- a/llvm/tools/llvm-mc/llvm-mc.cpp
+++ b/llvm/tools/llvm-mc/llvm-mc.cpp
@@ -567,7 +567,7 @@ int main(int argc, char **argv) {
     MCAsmBackend *MAB = nullptr;
     if (ShowEncoding) {
       CE = TheTarget->createMCCodeEmitter(*MCII, *MRI, Ctx);
-      MAB = TheTarget->createMCAsmBackend(*MRI, TripleName, MCPU, MCOptions);
+      MAB = TheTarget->createMCAsmBackend(*STI, *MRI, MCOptions);
     }
     auto FOut = llvm::make_unique<formatted_raw_ostream>(*OS);
     Str.reset(TheTarget->createAsmStreamer(
@@ -588,8 +588,7 @@ int main(int argc, char **argv) {
     }
 
     MCCodeEmitter *CE = TheTarget->createMCCodeEmitter(*MCII, *MRI, Ctx);
-    MCAsmBackend *MAB = TheTarget->createMCAsmBackend(*MRI, TripleName, MCPU,
-                                                      MCOptions);
+    MCAsmBackend *MAB = TheTarget->createMCAsmBackend(*STI, *MRI, MCOptions);
     Str.reset(TheTarget->createMCObjectStreamer(
         TheTriple, Ctx, std::unique_ptr<MCAsmBackend>(MAB), *OS,
         std::unique_ptr<MCCodeEmitter>(CE), *STI, MCOptions.MCRelaxAll,
diff --git a/llvm/unittests/DebugInfo/DWARF/DwarfGenerator.cpp b/llvm/unittests/DebugInfo/DWARF/DwarfGenerator.cpp
index 3aa52a0d5b8..092591aad98 100644
--- a/llvm/unittests/DebugInfo/DWARF/DwarfGenerator.cpp
+++ b/llvm/unittests/DebugInfo/DWARF/DwarfGenerator.cpp
@@ -152,8 +152,13 @@ llvm::Error dwarfgen::Generator::init(Triple TheTriple, uint16_t V) {
   MC.reset(new MCContext(MAI.get(), MRI.get(), MOFI.get()));
   MOFI->InitMCObjectFileInfo(TheTriple, /*PIC*/ false, *MC);
 
+  MSTI.reset(TheTarget->createMCSubtargetInfo(TripleName, "", ""));
+  if (!MSTI)
+    return make_error<StringError>("no subtarget info for target " + TripleName,
+                                   inconvertibleErrorCode());
+
   MCTargetOptions MCOptions = InitMCTargetOptionsFromFlags();
-  MAB = TheTarget->createMCAsmBackend(*MRI, TripleName, "", MCOptions);
+  MAB = TheTarget->createMCAsmBackend(*MSTI, *MRI, MCOptions);
   if (!MAB)
     return make_error<StringError>("no asm backend for target " + TripleName,
                                    inconvertibleErrorCode());
@@ -164,11 +169,6 @@ llvm::Error dwarfgen::Generator::init(Triple TheTriple, uint16_t V) {
                                        TripleName,
                                    inconvertibleErrorCode());
 
-  MSTI.reset(TheTarget->createMCSubtargetInfo(TripleName, "", ""));
-  if (!MSTI)
-    return make_error<StringError>("no subtarget info for target " + TripleName,
-                                   inconvertibleErrorCode());
-
   MCE = TheTarget->createMCCodeEmitter(*MII, *MRI, *MC);
   if (!MCE)
     return make_error<StringError>("no code emitter for target " + TripleName,