[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.

llvm-svn: 315410

5 files changed, 28 insertions, 17 deletions

diff --git a/llvm/lib/MC/MCELFStreamer.cpp b/llvm/lib/MC/MCELFStreamer.cpp
index 76976cab466..4fdbcd7511c 100644
--- a/llvm/lib/MC/MCELFStreamer.cpp
+++ b/llvm/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/llvm/lib/MC/MCMachOStreamer.cpp b/llvm/lib/MC/MCMachOStreamer.cpp
index 674c7b9bf61..293b87d4177 100644
--- a/llvm/lib/MC/MCMachOStreamer.cpp
+++ b/llvm/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/llvm/lib/MC/MCObjectStreamer.cpp b/llvm/lib/MC/MCObjectStreamer.cpp
index 46d57265d85..ba45d24fd08 100644
--- a/llvm/lib/MC/MCObjectStreamer.cpp
+++ b/llvm/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/llvm/lib/MC/MCWasmStreamer.cpp b/llvm/lib/MC/MCWasmStreamer.cpp
index be8a5c21610..fdf1be67e4e 100644
--- a/llvm/lib/MC/MCWasmStreamer.cpp
+++ b/llvm/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/llvm/lib/MC/MCWinCOFFStreamer.cpp b/llvm/lib/MC/MCWinCOFFStreamer.cpp
index dddafb9691c..c78a2e17c8d 100644
--- a/llvm/lib/MC/MCWinCOFFStreamer.cpp
+++ b/llvm/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) {