[MC] Have MCObjectStreamer take its MCAsmBackend argument via unique_ptr.

MCObjectStreamer owns its MCAsmBackend -- this fixes the types to reflect that,
and allows us to remove another instance of MCObjectStreamer's weird "holding
ownership via someone else's reference" trick.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@315410 91177308-0d34-0410-b5e6-96231b3b80d8

30 files changed, 203 insertions, 139 deletions

diff --git a/lib/CodeGen/LLVMTargetMachine.cpp b/lib/CodeGen/LLVMTargetMachine.cpp
index 753db852263..00db011697f 100644
--- a/lib/CodeGen/LLVMTargetMachine.cpp
+++ b/lib/CodeGen/LLVMTargetMachine.cpp
@@ -20,6 +20,7 @@
 #include "llvm/IR/IRPrintingPasses.h"
 #include "llvm/IR/LegacyPassManager.h"
 #include "llvm/IR/Verifier.h"
+#include "llvm/MC/MCAsmBackend.h"
 #include "llvm/MC/MCAsmInfo.h"
 #include "llvm/MC/MCContext.h"
 #include "llvm/MC/MCInstrInfo.h"
@@ -163,7 +164,8 @@ bool LLVMTargetMachine::addAsmPrinter(PassManagerBase &PM,
 
     Triple T(getTargetTriple().str());
     AsmStreamer.reset(getTarget().createMCObjectStreamer(
-        T, Context, *MAB, Out, MCE, STI, Options.MCOptions.MCRelaxAll,
+        T, Context, std::unique_ptr<MCAsmBackend>(MAB), Out, MCE, STI,
+        Options.MCOptions.MCRelaxAll,
         Options.MCOptions.MCIncrementalLinkerCompatible,
         /*DWARFMustBeAtTheEnd*/ true));
     break;
@@ -238,7 +240,8 @@ bool LLVMTargetMachine::addPassesToEmitMC(PassManagerBase &PM, MCContext *&Ctx,
   const Triple &T = getTargetTriple();
   const MCSubtargetInfo &STI = *getMCSubtargetInfo();
   std::unique_ptr<MCStreamer> AsmStreamer(getTarget().createMCObjectStreamer(
-      T, *Ctx, *MAB, Out, MCE, STI, Options.MCOptions.MCRelaxAll,
+      T, *Ctx, std::unique_ptr<MCAsmBackend>(MAB), Out, MCE, STI,
+      Options.MCOptions.MCRelaxAll,
       Options.MCOptions.MCIncrementalLinkerCompatible,
       /*DWARFMustBeAtTheEnd*/ true));
 
diff --git a/lib/MC/MCELFStreamer.cpp b/lib/MC/MCELFStreamer.cpp
index 76976cab466..4fdbcd7511c 100644
--- a/lib/MC/MCELFStreamer.cpp
+++ b/lib/MC/MCELFStreamer.cpp
@@ -39,6 +39,11 @@
 
 using namespace llvm;
 
+MCELFStreamer::MCELFStreamer(MCContext &Context,
+                             std::unique_ptr<MCAsmBackend> TAB,
+                             raw_pwrite_stream &OS, MCCodeEmitter *Emitter)
+    : MCObjectStreamer(Context, std::move(TAB), OS, Emitter) {}
+
 bool MCELFStreamer::isBundleLocked() const {
   return getCurrentSectionOnly()->isBundleLocked();
 }
@@ -639,10 +644,11 @@ void MCELFStreamer::EmitTBSSSymbol(MCSection *Section, MCSymbol *Symbol,
   llvm_unreachable("ELF doesn't support this directive");
 }
 
-MCStreamer *llvm::createELFStreamer(MCContext &Context, MCAsmBackend &MAB,
+MCStreamer *llvm::createELFStreamer(MCContext &Context,
+                                    std::unique_ptr<MCAsmBackend> &&MAB,
                                     raw_pwrite_stream &OS, MCCodeEmitter *CE,
                                     bool RelaxAll) {
-  MCELFStreamer *S = new MCELFStreamer(Context, MAB, OS, CE);
+  MCELFStreamer *S = new MCELFStreamer(Context, std::move(MAB), OS, CE);
   if (RelaxAll)
     S->getAssembler().setRelaxAll(true);
   return S;
diff --git a/lib/MC/MCMachOStreamer.cpp b/lib/MC/MCMachOStreamer.cpp
index 674c7b9bf61..293b87d4177 100644
--- a/lib/MC/MCMachOStreamer.cpp
+++ b/lib/MC/MCMachOStreamer.cpp
@@ -62,10 +62,12 @@ private:
   void EmitDataRegionEnd();
 
 public:
-  MCMachOStreamer(MCContext &Context, MCAsmBackend &MAB, raw_pwrite_stream &OS,
-                  MCCodeEmitter *Emitter, bool DWARFMustBeAtTheEnd, bool label)
-      : MCObjectStreamer(Context, MAB, OS, Emitter), LabelSections(label),
-        DWARFMustBeAtTheEnd(DWARFMustBeAtTheEnd), CreatedADWARFSection(false) {}
+  MCMachOStreamer(MCContext &Context, std::unique_ptr<MCAsmBackend> MAB,
+                  raw_pwrite_stream &OS, MCCodeEmitter *Emitter,
+                  bool DWARFMustBeAtTheEnd, bool label)
+      : MCObjectStreamer(Context, std::move(MAB), OS, Emitter),
+        LabelSections(label), DWARFMustBeAtTheEnd(DWARFMustBeAtTheEnd),
+        CreatedADWARFSection(false) {}
 
   /// state management
   void reset() override {
@@ -483,11 +485,12 @@ void MCMachOStreamer::FinishImpl() {
   this->MCObjectStreamer::FinishImpl();
 }
 
-MCStreamer *llvm::createMachOStreamer(MCContext &Context, MCAsmBackend &MAB,
+MCStreamer *llvm::createMachOStreamer(MCContext &Context,
+                                      std::unique_ptr<MCAsmBackend> &&MAB,
                                       raw_pwrite_stream &OS, MCCodeEmitter *CE,
                                       bool RelaxAll, bool DWARFMustBeAtTheEnd,
                                       bool LabelSections) {
-  MCMachOStreamer *S = new MCMachOStreamer(Context, MAB, OS, CE,
+  MCMachOStreamer *S = new MCMachOStreamer(Context, std::move(MAB), OS, CE,
                                            DWARFMustBeAtTheEnd, LabelSections);
   const Triple &TT = Context.getObjectFileInfo()->getTargetTriple();
   if (TT.isOSDarwin()) {
diff --git a/lib/MC/MCObjectStreamer.cpp b/lib/MC/MCObjectStreamer.cpp
index 46d57265d85..ba45d24fd08 100644
--- a/lib/MC/MCObjectStreamer.cpp
+++ b/lib/MC/MCObjectStreamer.cpp
@@ -25,16 +25,16 @@
 #include "llvm/Support/TargetRegistry.h"
 using namespace llvm;
 
-MCObjectStreamer::MCObjectStreamer(MCContext &Context, MCAsmBackend &TAB,
+MCObjectStreamer::MCObjectStreamer(MCContext &Context,
+                                   std::unique_ptr<MCAsmBackend> TAB,
                                    raw_pwrite_stream &OS,
                                    MCCodeEmitter *Emitter_)
-    : MCStreamer(Context), ObjectWriter(TAB.createObjectWriter(OS)),
-      Assembler(llvm::make_unique<MCAssembler>(Context, TAB, *Emitter_,
-                                               *ObjectWriter)),
+    : MCStreamer(Context), ObjectWriter(TAB->createObjectWriter(OS)),
+      TAB(std::move(TAB)), Assembler(llvm::make_unique<MCAssembler>(
+                               Context, *this->TAB, *Emitter_, *ObjectWriter)),
       EmitEHFrame(true), EmitDebugFrame(false) {}
 
 MCObjectStreamer::~MCObjectStreamer() {
-  delete &Assembler->getBackend();
   delete &Assembler->getEmitter();
 }
 
diff --git a/lib/MC/MCWasmStreamer.cpp b/lib/MC/MCWasmStreamer.cpp
index be8a5c21610..fdf1be67e4e 100644
--- a/lib/MC/MCWasmStreamer.cpp
+++ b/lib/MC/MCWasmStreamer.cpp
@@ -200,10 +200,11 @@ void MCWasmStreamer::FinishImpl() {
   this->MCObjectStreamer::FinishImpl();
 }
 
-MCStreamer *llvm::createWasmStreamer(MCContext &Context, MCAsmBackend &MAB,
+MCStreamer *llvm::createWasmStreamer(MCContext &Context,
+                                     std::unique_ptr<MCAsmBackend> &&MAB,
                                      raw_pwrite_stream &OS, MCCodeEmitter *CE,
                                      bool RelaxAll) {
-  MCWasmStreamer *S = new MCWasmStreamer(Context, MAB, OS, CE);
+  MCWasmStreamer *S = new MCWasmStreamer(Context, std::move(MAB), OS, CE);
   if (RelaxAll)
     S->getAssembler().setRelaxAll(true);
   return S;
diff --git a/lib/MC/MCWinCOFFStreamer.cpp b/lib/MC/MCWinCOFFStreamer.cpp
index dddafb9691c..c78a2e17c8d 100644
--- a/lib/MC/MCWinCOFFStreamer.cpp
+++ b/lib/MC/MCWinCOFFStreamer.cpp
@@ -41,9 +41,10 @@ using namespace llvm;
 
 #define DEBUG_TYPE "WinCOFFStreamer"
 
-MCWinCOFFStreamer::MCWinCOFFStreamer(MCContext &Context, MCAsmBackend &MAB,
+MCWinCOFFStreamer::MCWinCOFFStreamer(MCContext &Context,
+                                     std::unique_ptr<MCAsmBackend> MAB,
                                      MCCodeEmitter &CE, raw_pwrite_stream &OS)
-    : MCObjectStreamer(Context, MAB, OS, &CE), CurSymbol(nullptr) {}
+    : MCObjectStreamer(Context, std::move(MAB), OS, &CE), CurSymbol(nullptr) {}
 
 void MCWinCOFFStreamer::EmitInstToData(const MCInst &Inst,
                                        const MCSubtargetInfo &STI) {
diff --git a/lib/Target/AArch64/MCTargetDesc/AArch64ELFStreamer.cpp b/lib/Target/AArch64/MCTargetDesc/AArch64ELFStreamer.cpp
index a0de3c39562..380d5acafb4 100644
--- a/lib/Target/AArch64/MCTargetDesc/AArch64ELFStreamer.cpp
+++ b/lib/Target/AArch64/MCTargetDesc/AArch64ELFStreamer.cpp
@@ -86,10 +86,10 @@ class AArch64ELFStreamer : public MCELFStreamer {
 public:
   friend class AArch64TargetELFStreamer;
 
-  AArch64ELFStreamer(MCContext &Context, MCAsmBackend &TAB,
+  AArch64ELFStreamer(MCContext &Context, std::unique_ptr<MCAsmBackend> TAB,
                      raw_pwrite_stream &OS, MCCodeEmitter *Emitter)
-      : MCELFStreamer(Context, TAB, OS, Emitter), MappingSymbolCounter(0),
-        LastEMS(EMS_None) {}
+      : MCELFStreamer(Context, std::move(TAB), OS, Emitter),
+        MappingSymbolCounter(0), LastEMS(EMS_None) {}
 
   void ChangeSection(MCSection *Section, const MCExpr *Subsection) override {
     // We have to keep track of the mapping symbol state of any sections we
@@ -198,10 +198,12 @@ MCTargetStreamer *createAArch64AsmTargetStreamer(MCStreamer &S,
   return new AArch64TargetAsmStreamer(S, OS);
 }
 
-MCELFStreamer *createAArch64ELFStreamer(MCContext &Context, MCAsmBackend &TAB,
+MCELFStreamer *createAArch64ELFStreamer(MCContext &Context,
+                                        std::unique_ptr<MCAsmBackend> TAB,
                                         raw_pwrite_stream &OS,
                                         MCCodeEmitter *Emitter, bool RelaxAll) {
-  AArch64ELFStreamer *S = new AArch64ELFStreamer(Context, TAB, OS, Emitter);
+  AArch64ELFStreamer *S =
+      new AArch64ELFStreamer(Context, std::move(TAB), OS, Emitter);
   if (RelaxAll)
     S->getAssembler().setRelaxAll(true);
   return S;
diff --git a/lib/Target/AArch64/MCTargetDesc/AArch64ELFStreamer.h b/lib/Target/AArch64/MCTargetDesc/AArch64ELFStreamer.h
index ef48203c8bc..5869764a90d 100644
--- a/lib/Target/AArch64/MCTargetDesc/AArch64ELFStreamer.h
+++ b/lib/Target/AArch64/MCTargetDesc/AArch64ELFStreamer.h
@@ -18,7 +18,8 @@
 
 namespace llvm {
 
-MCELFStreamer *createAArch64ELFStreamer(MCContext &Context, MCAsmBackend &TAB,
+MCELFStreamer *createAArch64ELFStreamer(MCContext &Context,
+                                        std::unique_ptr<MCAsmBackend> TAB,
                                         raw_pwrite_stream &OS,
                                         MCCodeEmitter *Emitter, bool RelaxAll);
 }
diff --git a/lib/Target/AArch64/MCTargetDesc/AArch64MCTargetDesc.cpp b/lib/Target/AArch64/MCTargetDesc/AArch64MCTargetDesc.cpp
index 8618069fb0d..b6c0c7f01f6 100644
--- a/lib/Target/AArch64/MCTargetDesc/AArch64MCTargetDesc.cpp
+++ b/lib/Target/AArch64/MCTargetDesc/AArch64MCTargetDesc.cpp
@@ -100,26 +100,29 @@ static MCInstPrinter *createAArch64MCInstPrinter(const Triple &T,
 }
 
 static MCStreamer *createELFStreamer(const Triple &T, MCContext &Ctx,
-                                     MCAsmBackend &TAB, raw_pwrite_stream &OS,
+                                     std::unique_ptr<MCAsmBackend> &&TAB,
+                                     raw_pwrite_stream &OS,
                                      MCCodeEmitter *Emitter, bool RelaxAll) {
-  return createAArch64ELFStreamer(Ctx, TAB, OS, Emitter, RelaxAll);
+  return createAArch64ELFStreamer(Ctx, std::move(TAB), OS, Emitter, RelaxAll);
 }
 
-static MCStreamer *createMachOStreamer(MCContext &Ctx, MCAsmBackend &TAB,
+static MCStreamer *createMachOStreamer(MCContext &Ctx,
+                                       std::unique_ptr<MCAsmBackend> &&TAB,
                                        raw_pwrite_stream &OS,
                                        MCCodeEmitter *Emitter, bool RelaxAll,
                                        bool DWARFMustBeAtTheEnd) {
-  return createMachOStreamer(Ctx, TAB, OS, Emitter, RelaxAll,
+  return createMachOStreamer(Ctx, std::move(TAB), OS, Emitter, RelaxAll,
                              DWARFMustBeAtTheEnd,
                              /*LabelSections*/ true);
 }
 
-static MCStreamer *createWinCOFFStreamer(MCContext &Ctx, MCAsmBackend &TAB,
+static MCStreamer *createWinCOFFStreamer(MCContext &Ctx,
+                                         std::unique_ptr<MCAsmBackend> &&TAB,
                                          raw_pwrite_stream &OS,
                                          MCCodeEmitter *Emitter, bool RelaxAll,
                                          bool IncrementalLinkerCompatible) {
-  return createAArch64WinCOFFStreamer(Ctx, TAB, OS, Emitter, RelaxAll,
-                                      IncrementalLinkerCompatible);
+  return createAArch64WinCOFFStreamer(Ctx, std::move(TAB), OS, Emitter,
+                                      RelaxAll, IncrementalLinkerCompatible);
 }
 
 static MCInstrAnalysis *createAArch64InstrAnalysis(const MCInstrInfo *Info) {
diff --git a/lib/Target/AArch64/MCTargetDesc/AArch64WinCOFFStreamer.cpp b/lib/Target/AArch64/MCTargetDesc/AArch64WinCOFFStreamer.cpp
index 6c8da27e398..f1ab9ffbe84 100644
--- a/lib/Target/AArch64/MCTargetDesc/AArch64WinCOFFStreamer.cpp
+++ b/lib/Target/AArch64/MCTargetDesc/AArch64WinCOFFStreamer.cpp
@@ -17,19 +17,19 @@ class AArch64WinCOFFStreamer : public MCWinCOFFStreamer {
 public:
   friend class AArch64TargetWinCOFFStreamer;
 
-  AArch64WinCOFFStreamer(MCContext &C, MCAsmBackend &AB, MCCodeEmitter &CE,
-                        raw_pwrite_stream &OS)
-      : MCWinCOFFStreamer(C, AB, CE, OS) {}
+  AArch64WinCOFFStreamer(MCContext &C, std::unique_ptr<MCAsmBackend> AB,
+                         MCCodeEmitter &CE, raw_pwrite_stream &OS)
+      : MCWinCOFFStreamer(C, std::move(AB), CE, OS) {}
 };
 } // end anonymous namespace
 
 namespace llvm {
-MCWinCOFFStreamer
-*createAArch64WinCOFFStreamer(MCContext &Context, MCAsmBackend &MAB,
-                              raw_pwrite_stream &OS,
-                              MCCodeEmitter *Emitter, bool RelaxAll,
-                              bool IncrementalLinkerCompatible) {
-  auto *S = new AArch64WinCOFFStreamer(Context, MAB, *Emitter, OS);
+MCWinCOFFStreamer *
+createAArch64WinCOFFStreamer(MCContext &Context,
+                             std::unique_ptr<MCAsmBackend> MAB,
+                             raw_pwrite_stream &OS, MCCodeEmitter *Emitter,
+                             bool RelaxAll, bool IncrementalLinkerCompatible) {
+  auto *S = new AArch64WinCOFFStreamer(Context, std::move(MAB), *Emitter, OS);
   S->getAssembler().setIncrementalLinkerCompatible(IncrementalLinkerCompatible);
   return S;
 }
diff --git a/lib/Target/AArch64/MCTargetDesc/AArch64WinCOFFStreamer.h b/lib/Target/AArch64/MCTargetDesc/AArch64WinCOFFStreamer.h
index 1b4fcd6804e..0205a417898 100644
--- a/lib/Target/AArch64/MCTargetDesc/AArch64WinCOFFStreamer.h
+++ b/lib/Target/AArch64/MCTargetDesc/AArch64WinCOFFStreamer.h
@@ -15,6 +15,7 @@
 #define LLVM_LIB_TARGET_AARCH64_MCTARGETDESC_AARCH64WINCOFFSTREAMER_H
 
 #include "AArch64TargetStreamer.h"
+#include "llvm/MC/MCAsmBackend.h"
 #include "llvm/MC/MCWinCOFFStreamer.h"
 
 namespace {
@@ -33,11 +34,11 @@ public:
 
 namespace llvm {
 
-MCWinCOFFStreamer
-*createAArch64WinCOFFStreamer(MCContext &Context, MCAsmBackend &TAB,
-                              raw_pwrite_stream &OS,
-                              MCCodeEmitter *Emitter, bool RelaxAll,
-                              bool IncrementalLinkerCompatible);
+MCWinCOFFStreamer *
+createAArch64WinCOFFStreamer(MCContext &Context,
+                             std::unique_ptr<MCAsmBackend> TAB,
+                             raw_pwrite_stream &OS, MCCodeEmitter *Emitter,
+                             bool RelaxAll, bool IncrementalLinkerCompatible);
 } // end llvm namespace
 
 #endif
diff --git a/lib/Target/AMDGPU/MCTargetDesc/AMDGPUELFStreamer.cpp b/lib/Target/AMDGPU/MCTargetDesc/AMDGPUELFStreamer.cpp
index bfdb7d7cff7..875cdffea56 100644
--- a/lib/Target/AMDGPU/MCTargetDesc/AMDGPUELFStreamer.cpp
+++ b/lib/Target/AMDGPU/MCTargetDesc/AMDGPUELFStreamer.cpp
@@ -10,13 +10,15 @@
 #include "AMDGPUELFStreamer.h"
 #include "Utils/AMDGPUBaseInfo.h"
 #include "llvm/BinaryFormat/ELF.h"
+#include "llvm/MC/MCAsmBackend.h"
 
 using namespace llvm;
 
 AMDGPUELFStreamer::AMDGPUELFStreamer(const Triple &T, MCContext &Context,
-                                     MCAsmBackend &MAB, raw_pwrite_stream &OS,
+                                     std::unique_ptr<MCAsmBackend> MAB,
+                                     raw_pwrite_stream &OS,
                                      MCCodeEmitter *Emitter)
-    : MCELFStreamer(Context, MAB, OS, Emitter) {
+    : MCELFStreamer(Context, std::move(MAB), OS, Emitter) {
   unsigned Arch = ELF::EF_AMDGPU_ARCH_NONE;
   switch (T.getArch()) {
   case Triple::r600:
@@ -36,10 +38,8 @@ AMDGPUELFStreamer::AMDGPUELFStreamer(const Triple &T, MCContext &Context,
   MCA.setELFHeaderEFlags(EFlags);
 }
 
-MCELFStreamer *llvm::createAMDGPUELFStreamer(const Triple &T, MCContext &Context,
-                                             MCAsmBackend &MAB,
-                                             raw_pwrite_stream &OS,
-                                             MCCodeEmitter *Emitter,
-                                             bool RelaxAll) {
-  return new AMDGPUELFStreamer(T, Context, MAB, OS, Emitter);
+MCELFStreamer *llvm::createAMDGPUELFStreamer(
+    const Triple &T, MCContext &Context, std::unique_ptr<MCAsmBackend> MAB,
+    raw_pwrite_stream &OS, MCCodeEmitter *Emitter, bool RelaxAll) {
+  return new AMDGPUELFStreamer(T, Context, std::move(MAB), OS, Emitter);
 }
diff --git a/lib/Target/AMDGPU/MCTargetDesc/AMDGPUELFStreamer.h b/lib/Target/AMDGPU/MCTargetDesc/AMDGPUELFStreamer.h
index 386aa56c807..2de1786d348 100644
--- a/lib/Target/AMDGPU/MCTargetDesc/AMDGPUELFStreamer.h
+++ b/lib/Target/AMDGPU/MCTargetDesc/AMDGPUELFStreamer.h
@@ -25,12 +25,14 @@ class MCSubtargetInfo;
 
 class AMDGPUELFStreamer : public MCELFStreamer {
 public:
-  AMDGPUELFStreamer(const Triple &T, MCContext &Context, MCAsmBackend &MAB,
-                    raw_pwrite_stream &OS, MCCodeEmitter *Emitter);
+  AMDGPUELFStreamer(const Triple &T, MCContext &Context,
+                    std::unique_ptr<MCAsmBackend> MAB, raw_pwrite_stream &OS,
+                    MCCodeEmitter *Emitter);
 };
 
 MCELFStreamer *createAMDGPUELFStreamer(const Triple &T, MCContext &Context,
-                                       MCAsmBackend &MAB, raw_pwrite_stream &OS,
+                                       std::unique_ptr<MCAsmBackend> MAB,
+                                       raw_pwrite_stream &OS,
                                        MCCodeEmitter *Emitter, bool RelaxAll);
 } // namespace llvm.
 
diff --git a/lib/Target/AMDGPU/MCTargetDesc/AMDGPUMCTargetDesc.cpp b/lib/Target/AMDGPU/MCTargetDesc/AMDGPUMCTargetDesc.cpp
index 1682fc5e49b..578a3c25646 100644
--- a/lib/Target/AMDGPU/MCTargetDesc/AMDGPUMCTargetDesc.cpp
+++ b/lib/Target/AMDGPU/MCTargetDesc/AMDGPUMCTargetDesc.cpp
@@ -18,6 +18,7 @@
 #include "AMDGPUTargetStreamer.h"
 #include "InstPrinter/AMDGPUInstPrinter.h"
 #include "SIDefines.h"
+#include "llvm/MC/MCAsmBackend.h"
 #include "llvm/MC/MCContext.h"
 #include "llvm/MC/MCInstrInfo.h"
 #include "llvm/MC/MCRegisterInfo.h"
@@ -78,9 +79,11 @@ static MCTargetStreamer * createAMDGPUObjectTargetStreamer(
 }
 
 static MCStreamer *createMCStreamer(const Triple &T, MCContext &Context,
-                                    MCAsmBackend &MAB, raw_pwrite_stream &OS,
+                                    std::unique_ptr<MCAsmBackend> &&MAB,
+                                    raw_pwrite_stream &OS,
                                     MCCodeEmitter *Emitter, bool RelaxAll) {
-  return createAMDGPUELFStreamer(T, Context, MAB, OS, Emitter, RelaxAll);
+  return createAMDGPUELFStreamer(T, Context, std::move(MAB), OS, Emitter,
+                                 RelaxAll);
 }
 
 extern "C" void LLVMInitializeAMDGPUTargetMC() {
diff --git a/lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp b/lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp
index af11fa74bba..872ec19c0f6 100644
--- a/lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp
+++ b/lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp
@@ -440,9 +440,9 @@ class ARMELFStreamer : public MCELFStreamer {
 public:
   friend class ARMTargetELFStreamer;
 
-  ARMELFStreamer(MCContext &Context, MCAsmBackend &TAB, raw_pwrite_stream &OS,
-                 MCCodeEmitter *Emitter, bool IsThumb)
-      : MCELFStreamer(Context, TAB, OS, Emitter), IsThumb(IsThumb) {
+  ARMELFStreamer(MCContext &Context, std::unique_ptr<MCAsmBackend> TAB,
+                 raw_pwrite_stream &OS, MCCodeEmitter *Emitter, bool IsThumb)
+      : MCELFStreamer(Context, std::move(TAB), OS, Emitter), IsThumb(IsThumb) {
     EHReset();
   }
 
@@ -1485,19 +1485,21 @@ MCTargetStreamer *createARMObjectTargetStreamer(MCStreamer &S,
   return new ARMTargetStreamer(S);
 }
 
-MCELFStreamer *createARMELFStreamer(MCContext &Context, MCAsmBackend &TAB,
+MCELFStreamer *createARMELFStreamer(MCContext &Context,
+                                    std::unique_ptr<MCAsmBackend> TAB,
                                     raw_pwrite_stream &OS,
                                     MCCodeEmitter *Emitter, bool RelaxAll,
                                     bool IsThumb) {
-    ARMELFStreamer *S = new ARMELFStreamer(Context, TAB, OS, Emitter, IsThumb);
-    // FIXME: This should eventually end up somewhere else where more
-    // intelligent flag decisions can be made. For now we are just maintaining
-    // the status quo for ARM and setting EF_ARM_EABI_VER5 as the default.
-    S->getAssembler().setELFHeaderEFlags(ELF::EF_ARM_EABI_VER5);
-
-    if (RelaxAll)
-      S->getAssembler().setRelaxAll(true);
-    return S;
+  ARMELFStreamer *S =
+      new ARMELFStreamer(Context, std::move(TAB), OS, Emitter, IsThumb);
+  // FIXME: This should eventually end up somewhere else where more
+  // intelligent flag decisions can be made. For now we are just maintaining
+  // the status quo for ARM and setting EF_ARM_EABI_VER5 as the default.
+  S->getAssembler().setELFHeaderEFlags(ELF::EF_ARM_EABI_VER5);
+
+  if (RelaxAll)
+    S->getAssembler().setRelaxAll(true);
+  return S;
 }
 
 } // end namespace llvm
diff --git a/lib/Target/ARM/MCTargetDesc/ARMMCTargetDesc.cpp b/lib/Target/ARM/MCTargetDesc/ARMMCTargetDesc.cpp
index 088f59cda76..279558883bc 100644
--- a/lib/Target/ARM/MCTargetDesc/ARMMCTargetDesc.cpp
+++ b/lib/Target/ARM/MCTargetDesc/ARMMCTargetDesc.cpp
@@ -16,6 +16,7 @@
 #include "ARMMCAsmInfo.h"
 #include "InstPrinter/ARMInstPrinter.h"
 #include "llvm/ADT/Triple.h"
+#include "llvm/MC/MCAsmBackend.h"
 #include "llvm/MC/MCELFStreamer.h"
 #include "llvm/MC/MCInstrAnalysis.h"
 #include "llvm/MC/MCInstrInfo.h"
@@ -198,18 +199,21 @@ static MCAsmInfo *createARMMCAsmInfo(const MCRegisterInfo &MRI,
 }
 
 static MCStreamer *createELFStreamer(const Triple &T, MCContext &Ctx,
-                                     MCAsmBackend &MAB, raw_pwrite_stream &OS,
+                                     std::unique_ptr<MCAsmBackend> &&MAB,
+                                     raw_pwrite_stream &OS,
                                      MCCodeEmitter *Emitter, bool RelaxAll) {
-  return createARMELFStreamer(Ctx, MAB, OS, Emitter, false,
-                              (T.getArch() == Triple::thumb ||
-                               T.getArch() == Triple::thumbeb));
+  return createARMELFStreamer(
+      Ctx, std::move(MAB), OS, Emitter, false,
+      (T.getArch() == Triple::thumb || T.getArch() == Triple::thumbeb));
 }
 
-static MCStreamer *createARMMachOStreamer(MCContext &Ctx, MCAsmBackend &MAB,
+static MCStreamer *createARMMachOStreamer(MCContext &Ctx,
+                                          std::unique_ptr<MCAsmBackend> &&MAB,
                                           raw_pwrite_stream &OS,
                                           MCCodeEmitter *Emitter, bool RelaxAll,
                                           bool DWARFMustBeAtTheEnd) {
-  return createMachOStreamer(Ctx, MAB, OS, Emitter, false, DWARFMustBeAtTheEnd);
+  return createMachOStreamer(Ctx, std::move(MAB), OS, Emitter, false,
+                             DWARFMustBeAtTheEnd);
 }
 
 static MCInstPrinter *createARMMCInstPrinter(const Triple &T,
diff --git a/lib/Target/ARM/MCTargetDesc/ARMMCTargetDesc.h b/lib/Target/ARM/MCTargetDesc/ARMMCTargetDesc.h
index a1b93e57664..cdbc45dce22 100644
--- a/lib/Target/ARM/MCTargetDesc/ARMMCTargetDesc.h
+++ b/lib/Target/ARM/MCTargetDesc/ARMMCTargetDesc.h
@@ -93,7 +93,8 @@ MCAsmBackend *createThumbBEAsmBackend(const Target &T,
 
 // Construct a PE/COFF machine code streamer which will generate a PE/COFF
 // object file.
-MCStreamer *createARMWinCOFFStreamer(MCContext &Context, MCAsmBackend &MAB,
+MCStreamer *createARMWinCOFFStreamer(MCContext &Context,
+                                     std::unique_ptr<MCAsmBackend> &&MAB,
                                      raw_pwrite_stream &OS,
                                      MCCodeEmitter *Emitter, bool RelaxAll,
                                      bool IncrementalLinkerCompatible);
diff --git a/lib/Target/ARM/MCTargetDesc/ARMWinCOFFStreamer.cpp b/lib/Target/ARM/MCTargetDesc/ARMWinCOFFStreamer.cpp
index 83fa084e60c..d4c95c08cdd 100644
--- a/lib/Target/ARM/MCTargetDesc/ARMWinCOFFStreamer.cpp
+++ b/lib/Target/ARM/MCTargetDesc/ARMWinCOFFStreamer.cpp
@@ -8,6 +8,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "ARMMCTargetDesc.h"
+#include "llvm/MC/MCAsmBackend.h"
 #include "llvm/MC/MCWinCOFFStreamer.h"
 
 using namespace llvm;
@@ -15,9 +16,9 @@ using namespace llvm;
 namespace {
 class ARMWinCOFFStreamer : public MCWinCOFFStreamer {
 public:
-  ARMWinCOFFStreamer(MCContext &C, MCAsmBackend &AB, MCCodeEmitter &CE,
-                     raw_pwrite_stream &OS)
-      : MCWinCOFFStreamer(C, AB, CE, OS) {}
+  ARMWinCOFFStreamer(MCContext &C, std::unique_ptr<MCAsmBackend> AB,
+                     MCCodeEmitter &CE, raw_pwrite_stream &OS)
+      : MCWinCOFFStreamer(C, std::move(AB), CE, OS) {}
 
   void EmitAssemblerFlag(MCAssemblerFlag Flag) override;
   void EmitThumbFunc(MCSymbol *Symbol) override;
@@ -37,10 +38,13 @@ void ARMWinCOFFStreamer::EmitThumbFunc(MCSymbol *Symbol) {
 }
 }
 
-MCStreamer *llvm::createARMWinCOFFStreamer(
-    MCContext &Context, MCAsmBackend &MAB, raw_pwrite_stream &OS,
-    MCCodeEmitter *Emitter, bool RelaxAll, bool IncrementalLinkerCompatible) {
-  auto *S = new ARMWinCOFFStreamer(Context, MAB, *Emitter, OS);
+MCStreamer *llvm::createARMWinCOFFStreamer(MCContext &Context,
+                                           std::unique_ptr<MCAsmBackend> &&MAB,
+                                           raw_pwrite_stream &OS,
+                                           MCCodeEmitter *Emitter,
+                                           bool RelaxAll,
+                                           bool IncrementalLinkerCompatible) {
+  auto *S = new ARMWinCOFFStreamer(Context, std::move(MAB), *Emitter, OS);
   S->getAssembler().setIncrementalLinkerCompatible(IncrementalLinkerCompatible);
   return S;
 }
diff --git a/lib/Target/BPF/MCTargetDesc/BPFMCTargetDesc.cpp b/lib/Target/BPF/MCTargetDesc/BPFMCTargetDesc.cpp
index 797904e1c97..40459f57fee 100644
--- a/lib/Target/BPF/MCTargetDesc/BPFMCTargetDesc.cpp
+++ b/lib/Target/BPF/MCTargetDesc/BPFMCTargetDesc.cpp
@@ -49,11 +49,11 @@ static MCSubtargetInfo *createBPFMCSubtargetInfo(const Triple &TT,
   return createBPFMCSubtargetInfoImpl(TT, CPU, FS);
 }
 
-static MCStreamer *createBPFMCStreamer(const Triple &T,
-                                       MCContext &Ctx, MCAsmBackend &MAB,
-                                       raw_pwrite_stream &OS, MCCodeEmitter *Emitter,
-                                       bool RelaxAll) {
-  return createELFStreamer(Ctx, MAB, OS, Emitter, RelaxAll);
+static MCStreamer *createBPFMCStreamer(const Triple &T, MCContext &Ctx,
+                                       std::unique_ptr<MCAsmBackend> &&MAB,
+                                       raw_pwrite_stream &OS,
+                                       MCCodeEmitter *Emitter, bool RelaxAll) {
+  return createELFStreamer(Ctx, std::move(MAB), OS, Emitter, RelaxAll);
 }
 
 static MCInstPrinter *createBPFMCInstPrinter(const Triple &T,
diff --git a/lib/Target/Hexagon/MCTargetDesc/HexagonMCELFStreamer.cpp b/lib/Target/Hexagon/MCTargetDesc/HexagonMCELFStreamer.cpp
index 47007e08a2f..85b6296d805 100644
--- a/lib/Target/Hexagon/MCTargetDesc/HexagonMCELFStreamer.cpp
+++ b/lib/Target/Hexagon/MCTargetDesc/HexagonMCELFStreamer.cpp
@@ -18,6 +18,7 @@
 #include "MCTargetDesc/HexagonMCShuffler.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/BinaryFormat/ELF.h"
+#include "llvm/MC/MCAsmBackend.h"
 #include "llvm/MC/MCAssembler.h"
 #include "llvm/MC/MCContext.h"
 #include "llvm/MC/MCExpr.h"
@@ -43,6 +44,21 @@ static cl::opt<unsigned> GPSize
    cl::Prefix,
    cl::init(8));
 
+HexagonMCELFStreamer::HexagonMCELFStreamer(MCContext &Context,
+                                           std::unique_ptr<MCAsmBackend> TAB,
+                                           raw_pwrite_stream &OS,
+                                           MCCodeEmitter *Emitter)
+    : MCELFStreamer(Context, std::move(TAB), OS, Emitter),
+      MCII(createHexagonMCInstrInfo()) {}
+
+HexagonMCELFStreamer::HexagonMCELFStreamer(MCContext &Context,
+                                           std::unique_ptr<MCAsmBackend> TAB,
+                                           raw_pwrite_stream &OS,
+                                           MCCodeEmitter *Emitter,
+                                           MCAssembler *Assembler)
+    : MCELFStreamer(Context, std::move(TAB), OS, Emitter),
+      MCII(createHexagonMCInstrInfo()) {}
+
 void HexagonMCELFStreamer::EmitInstruction(const MCInst &MCB,
                                            const MCSubtargetInfo &STI, bool) {
   assert(MCB.getOpcode() == Hexagon::BUNDLE);
@@ -149,10 +165,10 @@ void HexagonMCELFStreamer::HexagonMCEmitLocalCommonSymbol(MCSymbol *Symbol,
 
 
 namespace llvm {
-  MCStreamer *createHexagonELFStreamer(Triple const &TT, MCContext &Context,
-                                       MCAsmBackend &MAB,
-                                       raw_pwrite_stream &OS, MCCodeEmitter *CE) {
-    return new HexagonMCELFStreamer(Context, MAB, OS, CE);
+MCStreamer *createHexagonELFStreamer(Triple const &TT, MCContext &Context,
+                                     std::unique_ptr<MCAsmBackend> MAB,
+                                     raw_pwrite_stream &OS, MCCodeEmitter *CE) {
+  return new HexagonMCELFStreamer(Context, std::move(MAB), OS, CE);
   }
 
 } // end namespace llvm
diff --git a/lib/Target/Hexagon/MCTargetDesc/HexagonMCELFStreamer.h b/lib/Target/Hexagon/MCTargetDesc/HexagonMCELFStreamer.h
index 024dff1a2f9..9c56dcff293 100644
--- a/lib/Target/Hexagon/MCTargetDesc/HexagonMCELFStreamer.h
+++ b/lib/Target/Hexagon/MCTargetDesc/HexagonMCELFStreamer.h
@@ -22,17 +22,12 @@ class HexagonMCELFStreamer : public MCELFStreamer {
   std::unique_ptr<MCInstrInfo> MCII;
 
 public:
-  HexagonMCELFStreamer(MCContext &Context, MCAsmBackend &TAB,
-                       raw_pwrite_stream &OS, MCCodeEmitter *Emitter)
-      : MCELFStreamer(Context, TAB, OS, Emitter),
-        MCII(createHexagonMCInstrInfo()) {}
+  HexagonMCELFStreamer(MCContext &Context, std::unique_ptr<MCAsmBackend> TAB,
+                       raw_pwrite_stream &OS, MCCodeEmitter *Emitter);
 
-  HexagonMCELFStreamer(MCContext &Context,
-                       MCAsmBackend &TAB,
+  HexagonMCELFStreamer(MCContext &Context, std::unique_ptr<MCAsmBackend> TAB,
                        raw_pwrite_stream &OS, MCCodeEmitter *Emitter,
-                       MCAssembler *Assembler) :
-  MCELFStreamer(Context, TAB, OS, Emitter),
-  MCII (createHexagonMCInstrInfo()) {}
+                       MCAssembler *Assembler);
 
   void EmitInstruction(const MCInst &Inst, const MCSubtargetInfo &STI,
                        bool) override;
@@ -45,8 +40,8 @@ public:
 };
 
 MCStreamer *createHexagonELFStreamer(Triple const &TT, MCContext &Context,
-                                     MCAsmBackend &MAB, raw_pwrite_stream &OS,
-                                     MCCodeEmitter *CE);
+                                     std::unique_ptr<MCAsmBackend> MAB,
+                                     raw_pwrite_stream &OS, MCCodeEmitter *CE);
 
 } // end namespace llvm
 
diff --git a/lib/Target/Hexagon/MCTargetDesc/HexagonMCTargetDesc.cpp b/lib/Target/Hexagon/MCTargetDesc/HexagonMCTargetDesc.cpp
index 1a361548f93..a695a3bdbc4 100644
--- a/lib/Target/Hexagon/MCTargetDesc/HexagonMCTargetDesc.cpp
+++ b/lib/Target/Hexagon/MCTargetDesc/HexagonMCTargetDesc.cpp
@@ -20,6 +20,7 @@
 #include "MCTargetDesc/HexagonMCInstrInfo.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/BinaryFormat/ELF.h"
+#include "llvm/MC/MCAsmBackend.h"
 #include "llvm/MC/MCContext.h"
 #include "llvm/MC/MCDwarf.h"
 #include "llvm/MC/MCELFStreamer.h"
@@ -224,13 +225,11 @@ createMCAsmTargetStreamer(MCStreamer &S, formatted_raw_ostream &OS,
   return new HexagonTargetAsmStreamer(S, OS, IsVerboseAsm, *IP);
 }
 
-static MCStreamer *createMCStreamer(Triple const &T,
-                                    MCContext &Context,
-                                    MCAsmBackend &MAB,
+static MCStreamer *createMCStreamer(Triple const &T, MCContext &Context,
+                                    std::unique_ptr<MCAsmBackend> &&MAB,
                                     raw_pwrite_stream &OS,
-                                    MCCodeEmitter *Emitter,
-                                    bool RelaxAll) {
-  return createHexagonELFStreamer(T, Context, MAB, OS, Emitter);
+                                    MCCodeEmitter *Emitter, bool RelaxAll) {
+  return createHexagonELFStreamer(T, Context, std::move(MAB), OS, Emitter);
 }
 
 static MCTargetStreamer *
diff --git a/lib/Target/Lanai/MCTargetDesc/LanaiMCTargetDesc.cpp b/lib/Target/Lanai/MCTargetDesc/LanaiMCTargetDesc.cpp
index bcbde2b8b79..a491efc322c 100644
--- a/lib/Target/Lanai/MCTargetDesc/LanaiMCTargetDesc.cpp
+++ b/lib/Target/Lanai/MCTargetDesc/LanaiMCTargetDesc.cpp
@@ -60,12 +60,13 @@ createLanaiMCSubtargetInfo(const Triple &TT, StringRef CPU, StringRef FS) {
 }
 
 static MCStreamer *createMCStreamer(const Triple &T, MCContext &Context,
-                                    MCAsmBackend &MAB, raw_pwrite_stream &OS,
+                                    std::unique_ptr<MCAsmBackend> &&MAB,
+                                    raw_pwrite_stream &OS,
                                     MCCodeEmitter *Emitter, bool RelaxAll) {
   if (!T.isOSBinFormatELF())
     llvm_unreachable("OS not supported");
 
-  return createELFStreamer(Context, MAB, OS, Emitter, RelaxAll);
+  return createELFStreamer(Context, std::move(MAB), OS, Emitter, RelaxAll);
 }
 
 static MCInstPrinter *createLanaiMCInstPrinter(const Triple & /*T*/,
diff --git a/lib/Target/Mips/MCTargetDesc/MipsELFStreamer.cpp b/lib/Target/Mips/MCTargetDesc/MipsELFStreamer.cpp
index f658aadff22..2a8e801763c 100644
--- a/lib/Target/Mips/MCTargetDesc/MipsELFStreamer.cpp
+++ b/lib/Target/Mips/MCTargetDesc/MipsELFStreamer.cpp
@@ -11,6 +11,7 @@
 #include "MipsOptionRecord.h"
 #include "MipsTargetStreamer.h"
 #include "llvm/BinaryFormat/ELF.h"
+#include "llvm/MC/MCAsmBackend.h"
 #include "llvm/MC/MCAssembler.h"
 #include "llvm/MC/MCContext.h"
 #include "llvm/MC/MCInst.h"
@@ -19,6 +20,15 @@
 
 using namespace llvm;
 
+MipsELFStreamer::MipsELFStreamer(MCContext &Context,
+                                 std::unique_ptr<MCAsmBackend> MAB,
+                                 raw_pwrite_stream &OS, MCCodeEmitter *Emitter)
+    : MCELFStreamer(Context, std::move(MAB), OS, Emitter) {
+  RegInfoRecord = new MipsRegInfoRecord(this, Context);
+  MipsOptionRecords.push_back(
+      std::unique_ptr<MipsRegInfoRecord>(RegInfoRecord));
+}
+
 void MipsELFStreamer::EmitInstruction(const MCInst &Inst,
                                       const MCSubtargetInfo &STI, bool) {
   MCELFStreamer::EmitInstruction(Inst, STI);
@@ -78,9 +88,9 @@ void MipsELFStreamer::EmitMipsOptionRecords() {
 }
 
 MCELFStreamer *llvm::createMipsELFStreamer(MCContext &Context,
-                                           MCAsmBackend &MAB,
+                                           std::unique_ptr<MCAsmBackend> MAB,
                                            raw_pwrite_stream &OS,
                                            MCCodeEmitter *Emitter,
                                            bool RelaxAll) {
-  return new MipsELFStreamer(Context, MAB, OS, Emitter);
+  return new MipsELFStreamer(Context, std::move(MAB), OS, Emitter);
 }
diff --git a/lib/Target/Mips/MCTargetDesc/MipsELFStreamer.h b/lib/Target/Mips/MCTargetDesc/MipsELFStreamer.h
index f5eda112817..e087f12f181 100644
--- a/lib/Target/Mips/MCTargetDesc/MipsELFStreamer.h
+++ b/lib/Target/Mips/MCTargetDesc/MipsELFStreamer.h
@@ -33,13 +33,8 @@ class MipsELFStreamer : public MCELFStreamer {
   SmallVector<MCSymbol*, 4> Labels;
 
 public:
-  MipsELFStreamer(MCContext &Context, MCAsmBackend &MAB, raw_pwrite_stream &OS,
-                  MCCodeEmitter *Emitter)
-      : MCELFStreamer(Context, MAB, OS, Emitter) {
-    RegInfoRecord = new MipsRegInfoRecord(this, Context);
-    MipsOptionRecords.push_back(
-        std::unique_ptr<MipsRegInfoRecord>(RegInfoRecord));
-  }
+  MipsELFStreamer(MCContext &Context, std::unique_ptr<MCAsmBackend> MAB,
+                  raw_pwrite_stream &OS, MCCodeEmitter *Emitter);
 
   /// Overriding this function allows us to add arbitrary behaviour before the
   /// \p Inst is actually emitted. For example, we can inspect the operands and
@@ -69,7 +64,8 @@ public:
   void createPendingLabelRelocs();
 };
 
-MCELFStreamer *createMipsELFStreamer(MCContext &Context, MCAsmBackend &MAB,
+MCELFStreamer *createMipsELFStreamer(MCContext &Context,
+                                     std::unique_ptr<MCAsmBackend> MAB,
                                      raw_pwrite_stream &OS,
                                      MCCodeEmitter *Emitter, bool RelaxAll);
 } // end namespace llvm
diff --git a/lib/Target/Mips/MCTargetDesc/MipsMCNaCl.h b/lib/Target/Mips/MCTargetDesc/MipsMCNaCl.h
index 687b800c240..cbddef7dd5f 100644
--- a/lib/Target/Mips/MCTargetDesc/MipsMCNaCl.h
+++ b/lib/Target/Mips/MCTargetDesc/MipsMCNaCl.h
@@ -22,7 +22,8 @@ bool isBasePlusOffsetMemoryAccess(unsigned Opcode, unsigned *AddrIdx,
 bool baseRegNeedsLoadStoreMask(unsigned Reg);
 
 // This function creates an MCELFStreamer for Mips NaCl.
-MCELFStreamer *createMipsNaClELFStreamer(MCContext &Context, MCAsmBackend &TAB,
+MCELFStreamer *createMipsNaClELFStreamer(MCContext &Context,
+                                         std::unique_ptr<MCAsmBackend> TAB,
                                          raw_pwrite_stream &OS,
                                          MCCodeEmitter *Emitter, bool RelaxAll);
 }
diff --git a/lib/Target/Mips/MCTargetDesc/MipsMCTargetDesc.cpp b/lib/Target/Mips/MCTargetDesc/MipsMCTargetDesc.cpp
index e05cbc55ffe..30474e02a22 100644
--- a/lib/Target/Mips/MCTargetDesc/MipsMCTargetDesc.cpp
+++ b/lib/Target/Mips/MCTargetDesc/MipsMCTargetDesc.cpp
@@ -91,13 +91,15 @@ static MCInstPrinter *createMipsMCInstPrinter(const Triple &T,
 }
 
 static MCStreamer *createMCStreamer(const Triple &T, MCContext &Context,
-                                    MCAsmBackend &MAB, raw_pwrite_stream &OS,
+                                    std::unique_ptr<MCAsmBackend> &&MAB,
+                                    raw_pwrite_stream &OS,
                                     MCCodeEmitter *Emitter, bool RelaxAll) {
   MCStreamer *S;
   if (!T.isOSNaCl())
-    S = createMipsELFStreamer(Context, MAB, OS, Emitter, RelaxAll);
+    S = createMipsELFStreamer(Context, std::move(MAB), OS, Emitter, RelaxAll);
   else
-    S = createMipsNaClELFStreamer(Context, MAB, OS, Emitter, RelaxAll);
+    S = createMipsNaClELFStreamer(Context, std::move(MAB), OS, Emitter,
+                                  RelaxAll);
   return S;
 }
 
diff --git a/lib/Target/Mips/MCTargetDesc/MipsNaClELFStreamer.cpp b/lib/Target/Mips/MCTargetDesc/MipsNaClELFStreamer.cpp
index 9266f0e216d..666876d5a32 100644
--- a/lib/Target/Mips/MCTargetDesc/MipsNaClELFStreamer.cpp
+++ b/lib/Target/Mips/MCTargetDesc/MipsNaClELFStreamer.cpp
@@ -20,6 +20,7 @@
 #include "Mips.h"
 #include "MipsELFStreamer.h"
 #include "MipsMCNaCl.h"
+#include "llvm/MC/MCAsmBackend.h"
 #include "llvm/MC/MCAssembler.h"
 #include "llvm/MC/MCELFStreamer.h"
 #include "llvm/MC/MCInst.h"
@@ -40,9 +41,9 @@ const unsigned LoadStoreStackMaskReg = Mips::T7;
 
 class MipsNaClELFStreamer : public MipsELFStreamer {
 public:
-  MipsNaClELFStreamer(MCContext &Context, MCAsmBackend &TAB,
+  MipsNaClELFStreamer(MCContext &Context, std::unique_ptr<MCAsmBackend> TAB,
                       raw_pwrite_stream &OS, MCCodeEmitter *Emitter)
-      : MipsELFStreamer(Context, TAB, OS, Emitter) {}
+      : MipsELFStreamer(Context, std::move(TAB), OS, Emitter) {}
 
   ~MipsNaClELFStreamer() override = default;
 
@@ -255,11 +256,13 @@ bool baseRegNeedsLoadStoreMask(unsigned Reg) {
   return Reg != Mips::SP && Reg != Mips::T8;
 }
 
-MCELFStreamer *createMipsNaClELFStreamer(MCContext &Context, MCAsmBackend &TAB,
+MCELFStreamer *createMipsNaClELFStreamer(MCContext &Context,
+                                         std::unique_ptr<MCAsmBackend> TAB,
                                          raw_pwrite_stream &OS,
                                          MCCodeEmitter *Emitter,
                                          bool RelaxAll) {
-  MipsNaClELFStreamer *S = new MipsNaClELFStreamer(Context, TAB, OS, Emitter);
+  MipsNaClELFStreamer *S =
+      new MipsNaClELFStreamer(Context, std::move(TAB), OS, Emitter);
   if (RelaxAll)
     S->getAssembler().setRelaxAll(true);
 
diff --git a/lib/Target/X86/MCTargetDesc/X86MCTargetDesc.h b/lib/Target/X86/MCTargetDesc/X86MCTargetDesc.h
index 82e70119ca5..327852396e4 100644
--- a/lib/Target/X86/MCTargetDesc/X86MCTargetDesc.h
+++ b/lib/Target/X86/MCTargetDesc/X86MCTargetDesc.h
@@ -81,9 +81,11 @@ MCAsmBackend *createX86_64AsmBackend(const Target &T, const MCRegisterInfo &MRI,
 /// PE/COFF format object files.
 ///
 /// Takes ownership of \p AB and \p CE.
-MCStreamer *createX86WinCOFFStreamer(MCContext &C, MCAsmBackend &AB,
+MCStreamer *createX86WinCOFFStreamer(MCContext &C,
+                                     std::unique_ptr<MCAsmBackend> &&AB,
                                      raw_pwrite_stream &OS, MCCodeEmitter *CE,
-                                     bool RelaxAll, bool IncrementalLinkerCompatible);
+                                     bool RelaxAll,
+                                     bool IncrementalLinkerCompatible);
 
 /// Construct an X86 Mach-O object writer.
 std::unique_ptr<MCObjectWriter> createX86MachObjectWriter(raw_pwrite_stream &OS,
diff --git a/lib/Target/X86/MCTargetDesc/X86WinCOFFStreamer.cpp b/lib/Target/X86/MCTargetDesc/X86WinCOFFStreamer.cpp
index cec0f9244c9..487823b258a 100644
--- a/lib/Target/X86/MCTargetDesc/X86WinCOFFStreamer.cpp
+++ b/lib/Target/X86/MCTargetDesc/X86WinCOFFStreamer.cpp
@@ -8,6 +8,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "X86MCTargetDesc.h"
+#include "llvm/MC/MCAsmBackend.h"
 #include "llvm/MC/MCWin64EH.h"
 #include "llvm/MC/MCWinCOFFStreamer.h"
 
@@ -17,9 +18,9 @@ namespace {
 class X86WinCOFFStreamer : public MCWinCOFFStreamer {
   Win64EH::UnwindEmitter EHStreamer;
 public:
-  X86WinCOFFStreamer(MCContext &C, MCAsmBackend &AB, MCCodeEmitter *CE,
-                     raw_pwrite_stream &OS)
-      : MCWinCOFFStreamer(C, AB, *CE, OS) {}
+  X86WinCOFFStreamer(MCContext &C, std::unique_ptr<MCAsmBackend> AB,
+                     MCCodeEmitter *CE, raw_pwrite_stream &OS)
+      : MCWinCOFFStreamer(C, std::move(AB), *CE, OS) {}
 
   void EmitWinEHHandlerData(SMLoc Loc) override;
   void EmitWindowsUnwindTables() override;
@@ -48,11 +49,12 @@ void X86WinCOFFStreamer::FinishImpl() {
 }
 }
 
-MCStreamer *llvm::createX86WinCOFFStreamer(MCContext &C, MCAsmBackend &AB,
+MCStreamer *llvm::createX86WinCOFFStreamer(MCContext &C,
+                                           std::unique_ptr<MCAsmBackend> &&AB,
                                            raw_pwrite_stream &OS,
                                            MCCodeEmitter *CE, bool RelaxAll,
                                            bool IncrementalLinkerCompatible) {
-  X86WinCOFFStreamer *S = new X86WinCOFFStreamer(C, AB, CE, OS);
+  X86WinCOFFStreamer *S = new X86WinCOFFStreamer(C, std::move(AB), CE, OS);
   S->getAssembler().setRelaxAll(RelaxAll);
   S->getAssembler().setIncrementalLinkerCompatible(IncrementalLinkerCompatible);
   return S;