[MC] Make it possible for targets to define their own MCObjectFileInfo

[flip1995]

Summary

This MCObjectFileInfo is then used to determine things like section
alignment.

For example, this commit removes the hard-coded 4-byte alignment for
text sections and uses the alignment defined by the target specific
MCObjectFileInfo.

This is a follow up to https://reviews.llvm.org/D101462 and prepares for the
RISCV backend defining the text section alignment depending on the enabled
extensions.

[flip1995]

rebased

[MaskRay]

Can you post the RISCV patch depending on this one?

llvm/include/llvm/Support/TargetRegistry.h

1029

https://llvm.org/docs/CodingStandards.html#doxygen-use-in-documentation-comments
"Don’t duplicate function or class name at the beginning of the comment."

Just ignore existing comments which do not abide by the standard.

llvm/lib/DWARFLinker/DWARFStreamer.cpp

57–60

The argument is almost always /*MOFI=*/nullptr. Doesn't this regress a bit?

[flip1995]

This comment was removed by flip1995.

llvm/include/llvm/Support/TargetRegistry.h

1029

https://llvm.org/docs/CodingStandards.html#doxygen-use-in-documentation-comments
"Don’t duplicate function or class name at the beginning of the comment."

Just ignore existing comments which do not abide by the standard.

[flip1995]

llvm/lib/DWARFLinker/DWARFStreamer.cpp

57–60

I agree. I think the best thing to do here would be to just remove this argument?

[flip1995]

In D101921#2743735, @MaskRay wrote:

Can you post the RISCV patch depending on this one?

Yes, sure. See https://reviews.llvm.org/D102052.

[flip1995]

Remove redundant item names in doc comments

[MaskRay]

llvm/include/llvm/MC/MCObjectFileInfo.h

255

This should be moved to D102052

llvm/lib/DWARFLinker/DWARFStreamer.cpp

57–60

I think so. Since MOFI is guaranteed to be constructed after MCContext now.

[MaskRay]

clang/tools/driver/cc1as_main.cpp

407–412

Can we fix the FIXME now?

[flip1995]

clang/tools/driver/cc1as_main.cpp

407–412

Not quite. The construction is still in the order MCContext -> MOFI -> "continue construction of MCContext by setting the MOFI". The order just changed from "dummy MOFI" -> MCContext -> "init dummy MOFI".

llvm/include/llvm/MC/MCObjectFileInfo.h

255

Will do.

llvm/lib/DWARFLinker/DWARFStreamer.cpp

57–60

Will do.

[flip1995]

rebased and addressed review comments:

• [MC] Remove MOFI argument from MCContext constructor
• [MC] Remove getTextSectionAlignment function from MCObjectFileInfo

[MaskRay]

Can createMCObjectFileInfo return MCObjectFileInfo instead of std::unique_ptr<MCObjectFileInfo>?

clang/lib/Parse/ParseStmtAsm.cpp

591

Can MOFI be null? (i.e. can createMCObjectFileInfo guarantee no-null return value?)

Consider moving the construction below the checks.

[flip1995]

In D101921#2754426, @MaskRay wrote:

Can createMCObjectFileInfo return MCObjectFileInfo instead of std::unique_ptr<MCObjectFileInfo>?

createMCObjectfileInfo returns a MCObjectFileInfo * similar to every other create* function in TargetRegistry.h.

clang/lib/Parse/ParseStmtAsm.cpp

591

You're right. The createMCObjectFileInfo always returns a no-null value. I'll move the construction and remove the check for MOFI.

[flip1995]

• [MC] Don't check if constructed MOFI is a nullptr

[MaskRay]

LGTM. This looks like an improvement because it avoids a temporary MCObjectFileInfo MOFI; (which appeared to be initialized in two subsequent calls) in numerous places.

[MaskRay]

llvm/include/llvm/Support/TargetRegistry.h

26

include/llvm/Support/TargetRegistry.h now has cyclic dependency on include/MC/*.h.

The previous style isn't good as well: include/llvm/Support/TargetRegistry.h has forward declarations of a number of MC* classes.

I think this header probably should be moved to lib/Target.

[flip1995]

llvm/include/llvm/Support/TargetRegistry.h

26

include/llvm/Support/TargetRegistry.h now has cyclic dependency on include/MC/*.h

I'll submit a quick fix changing this to a forward decl.

I think this header probably should be moved to lib/Target.

The whole TargetRegistry.h header?

[flip1995]

llvm/include/llvm/Support/TargetRegistry.h

26

I'll submit a quick fix changing this to a forward decl.

I just noticed, that this isn't as easy, as I would've thought, since the MOFI is constructed if no createMCObjectFileInfo callback function is defined by the target.

[MaskRay]

Because of new MCObjectFileInfo, we cannot use a forward declaration (incomplete class) to replace #include "llvm/MC/MCObjectFileInfo.h" in TargetRegistry.h.

I thought about moving TargetRegistry.{h,cpp} from Support to Target. However, it doesn't work because Bitcode/Object call TargetRegistry::lookupTarget and Bitcode/Object are lower than Target.

@compnerd @dblaikie @mehdi_amini Do you have suggestions on fixing the layering?

[dblaikie]

In D101921#2786245, @MaskRay wrote:

Because of new MCObjectFileInfo, we cannot use a forward declaration (incomplete class) to replace #include "llvm/MC/MCObjectFileInfo.h" in TargetRegistry.h.

I thought about moving TargetRegistry.{h,cpp} from Support to Target. However, it doesn't work because Bitcode/Object call TargetRegistry::lookupTarget and Bitcode/Object are lower than Target.

@compnerd @dblaikie @mehdi_amini Do you have suggestions on fixing the layering?

Looks like a big patch and a bit hard for me to page in all the context. Could you summarize the layering constraints/what headers/types/functions are in which libraries and why they are there/what constrains them?

clang/lib/Parse/ParseStmtAsm.cpp

if (!MRI) {
     return EmptyStmt();
   }
   // FIXME: init MCOptions from sanitizer flags here.
   llvm::MCTargetOptions MCOptions;
   std::unique_ptr<llvm::MCAsmInfo> MAI(
       TheTarget->createMCAsmInfo(*MRI, TT, MCOptions));
   // Get the instruction descriptor.
   std::unique_ptr<llvm::MCInstrInfo> MII(TheTarget->createMCInstrInfo());
-  std::unique_ptr<llvm::MCObjectFileInfo> MOFI(new llvm::MCObjectFileInfo());
   std::unique_ptr<llvm::MCSubtargetInfo> STI(
       TheTarget->createMCSubtargetInfo(TT, TO.CPU, FeaturesStr));
   // Target MCTargetDesc may not be linked in clang-based tools.
+
+  llvm::SourceMgr TempSrcMgr;
+  llvm::MCContext Ctx(TheTriple, MAI.get(), MRI.get(), /*MOFI=*/nullptr,
+                      STI.get(), &TempSrcMgr);
+  std::unique_ptr<llvm::MCObjectFileInfo> MOFI(
+      TheTarget->createMCObjectFileInfo(Ctx, /*PIC=*/false));
+  Ctx.setObjectFileInfo(MOFI.get());
+
   if (!MAI || !MII || !MOFI || !STI) {
     Diag(AsmLoc, diag::err_msasm_unable_to_create_target)
         << "target MC unavailable";
     return EmptyStmt();
   }
 
-  llvm::SourceMgr TempSrcMgr;
-  llvm::MCContext Ctx(TheTriple, MAI.get(), MRI.get(), MOFI.get(), STI.get(),
-                      &TempSrcMgr);
-  MOFI->initMCObjectFileInfo(Ctx, /*PIC=*/false);
   std::unique_ptr<llvm::MemoryBuffer> Buffer =
       llvm::MemoryBuffer::getMemBuffer(AsmString, "<MS inline asm>");
 
   // Tell SrcMgr about this buffer, which is what the parser will pick up.
   TempSrcMgr.AddNewSourceBuffer(std::move(Buffer), llvm::SMLoc());
 
   std::unique_ptr<llvm::MCStreamer> Str(createNullStreamer(Ctx));
   std::unique_ptr<llvm::MCAsmParser> Parser(

clang/tools/driver/cc1as_main.cpp

static bool ExecuteAssemblerImpl(AssemblerInvocation &Opts,
   std::unique_ptr<raw_fd_ostream> FDOS =
       getOutputStream(Opts.OutputPath, Diags, IsBinary);
   if (!FDOS)
     return true;
   std::unique_ptr<raw_fd_ostream> DwoOS;
   if (!Opts.SplitDwarfOutput.empty())
     DwoOS = getOutputStream(Opts.SplitDwarfOutput, Diags, IsBinary);
 
-  // FIXME: This is not pretty. MCContext has a ptr to MCObjectFileInfo and
-  // MCObjectFileInfo needs a MCContext reference in order to initialize itself.
-  std::unique_ptr<MCObjectFileInfo> MOFI(new MCObjectFileInfo());
-
   // Build up the feature string from the target feature list.
   std::string FS = llvm::join(Opts.Features, ",");
 
   std::unique_ptr<MCSubtargetInfo> STI(
       TheTarget->createMCSubtargetInfo(Opts.Triple, Opts.CPU, FS));
   assert(STI && "Unable to create subtarget info!");
 
-  MCContext Ctx(Triple(Opts.Triple), MAI.get(), MRI.get(), MOFI.get(),
+  MCContext Ctx(Triple(Opts.Triple), MAI.get(), MRI.get(), /*MOFI=*/nullptr,
                 STI.get(), &SrcMgr, &MCOptions);
 
   bool PIC = false;
   if (Opts.RelocationModel == "static") {
     PIC = false;
   } else if (Opts.RelocationModel == "pic") {
     PIC = true;
   } else {
     assert(Opts.RelocationModel == "dynamic-no-pic" &&
            "Invalid PIC model!");
     PIC = false;
   }
 
-  MOFI->initMCObjectFileInfo(Ctx, PIC);
+  // FIXME: This is not pretty. MCContext has a ptr to MCObjectFileInfo and
+  // MCObjectFileInfo needs a MCContext reference in order to initialize itself.
+  std::unique_ptr<MCObjectFileInfo> MOFI(
+      TheTarget->createMCObjectFileInfo(Ctx, PIC));
+  Ctx.setObjectFileInfo(MOFI.get());
+
   if (Opts.SaveTemporaryLabels)
     Ctx.setAllowTemporaryLabels(false);
   if (Opts.GenDwarfForAssembly)
     Ctx.setGenDwarfForAssembly(true);
   if (!Opts.DwarfDebugFlags.empty())
     Ctx.setDwarfDebugFlags(StringRef(Opts.DwarfDebugFlags));
   if (!Opts.DwarfDebugProducer.empty())
     Ctx.setDwarfDebugProducer(StringRef(Opts.DwarfDebugProducer));

llvm/include/llvm/MC/MCContext.h

public:
     SourceMgr *getInlineSourceManager() {
       return InlineSrcMgr.get();
     }
     std::vector<const MDNode *> &getLocInfos() { return LocInfos; }
     void setDiagnosticHandler(DiagHandlerTy DiagHandler) {
       this->DiagHandler = DiagHandler;
     }
 
+    void setObjectFileInfo(const MCObjectFileInfo *Mofi) { MOFI = Mofi; }
+
     const MCAsmInfo *getAsmInfo() const { return MAI; }
 
     const MCRegisterInfo *getRegisterInfo() const { return MRI; }
 
     const MCObjectFileInfo *getObjectFileInfo() const { return MOFI; }
 
     const MCSubtargetInfo *getSubtargetInfo() const { return MSTI; }
 

llvm/include/llvm/MC/MCObjectFileInfo.h

protected:
   MCSection *GLJMPSection = nullptr;
 
   // XCOFF specific sections
   MCSection *TOCBaseSection = nullptr;
 
 public:
   void initMCObjectFileInfo(MCContext &MCCtx, bool PIC,
                             bool LargeCodeModel = false);
+  virtual ~MCObjectFileInfo();
   MCContext &getContext() const { return *Ctx; }
 
   bool getSupportsWeakOmittedEHFrame() const {
     return SupportsWeakOmittedEHFrame;
   }
   bool getSupportsCompactUnwindWithoutEHFrame() const {
     return SupportsCompactUnwindWithoutEHFrame;
   }
   bool getOmitDwarfIfHaveCompactUnwind() const {
     return OmitDwarfIfHaveCompactUnwind;
   }
 
   bool getCommDirectiveSupportsAlignment() const {
     return CommDirectiveSupportsAlignment;
   }
 
   unsigned getFDEEncoding() const { return FDECFIEncoding; }
 
   unsigned getCompactUnwindDwarfEHFrameOnly() const {
     return CompactUnwindDwarfEHFrameOnly;
   }
 
+  virtual unsigned getTextSectionAlignment() const { return 4; }
   MCSection *getTextSection() const { return TextSection; }
   MCSection *getDataSection() const { return DataSection; }
   MCSection *getBSSSection() const { return BSSSection; }
   MCSection *getReadOnlySection() const { return ReadOnlySection; }
   MCSection *getCompactUnwindSection() const { return CompactUnwindSection; }
   MCSection *getDwarfAbbrevSection() const { return DwarfAbbrevSection; }
   MCSection *getDwarfInfoSection() const { return DwarfInfoSection; }
   MCSection *getDwarfInfoSection(uint64_t Hash) const {

llvm/include/llvm/Support/TargetRegistry.h

 #ifndef LLVM_SUPPORT_TARGETREGISTRY_H
 #define LLVM_SUPPORT_TARGETREGISTRY_H
 
 #include "llvm-c/DisassemblerTypes.h"
 #include "llvm/ADT/Optional.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/ADT/Triple.h"
 #include "llvm/ADT/iterator_range.h"
+#include "llvm/MC/MCObjectFileInfo.h"
 #include "llvm/Support/CodeGen.h"
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/FormattedStream.h"
 #include <algorithm>
 #include <cassert>
 #include <cstddef>
 #include <iterator>
 #include <memory>

 public:
   friend struct TargetRegistry;
 
   using ArchMatchFnTy = bool (*)(Triple::ArchType Arch);
 
   using MCAsmInfoCtorFnTy = MCAsmInfo *(*)(const MCRegisterInfo &MRI,
                                            const Triple &TT,
                                            const MCTargetOptions &Options);
+  using MCObjectFileInfoCtorFnTy = MCObjectFileInfo *(*)(MCContext &Ctx,
+                                                         bool PIC,
+                                                         bool LargeCodeModel);
   using MCInstrInfoCtorFnTy = MCInstrInfo *(*)();
   using MCInstrAnalysisCtorFnTy = MCInstrAnalysis *(*)(const MCInstrInfo *Info);
   using MCRegInfoCtorFnTy = MCRegisterInfo *(*)(const Triple &TT);
   using MCSubtargetInfoCtorFnTy = MCSubtargetInfo *(*)(const Triple &TT,
                                                        StringRef CPU,
                                                        StringRef Features);
   using TargetMachineCtorTy = TargetMachine
       *(*)(const Target &T, const Triple &TT, StringRef CPU, StringRef Features,
private:
 
   /// HasJIT - Whether this target supports the JIT.
   bool HasJIT;
 
   /// MCAsmInfoCtorFn - Constructor function for this target's MCAsmInfo, if
   /// registered.
   MCAsmInfoCtorFnTy MCAsmInfoCtorFn;
 
+  /// MCObjectFileInfoCtorFn - Constructor function for this target's
+  /// MCObjectFileInfo, if registered.
+  MCObjectFileInfoCtorFnTy MCObjectFileInfoCtorFn;
+
   /// MCInstrInfoCtorFn - Constructor function for this target's MCInstrInfo,
   /// if registered.
   MCInstrInfoCtorFnTy MCInstrInfoCtorFn;
 
   /// MCInstrAnalysisCtorFn - Constructor function for this target's
   /// MCInstrAnalysis, if registered.
   MCInstrAnalysisCtorFnTy MCInstrAnalysisCtorFn;
 
public:
   /// host if that does not exist.
   MCAsmInfo *createMCAsmInfo(const MCRegisterInfo &MRI, StringRef TheTriple,
                              const MCTargetOptions &Options) const {
     if (!MCAsmInfoCtorFn)
       return nullptr;
     return MCAsmInfoCtorFn(MRI, Triple(TheTriple), Options);
   }
 
+  /// createMCObjectFileInfo - Create a MCObjectFileInfo implementation for the
+  /// specified target triple.
+  ///
+  MCObjectFileInfo *createMCObjectFileInfo(MCContext &Ctx, bool PIC,
+                                           bool LargeCodeModel = false) const {
+    if (!MCObjectFileInfoCtorFn) {
+      MCObjectFileInfo *MOFI = new MCObjectFileInfo();
+      MOFI->initMCObjectFileInfo(Ctx, PIC, LargeCodeModel);
+      return MOFI;
+    }
+    return MCObjectFileInfoCtorFn(Ctx, PIC, LargeCodeModel);
+  }
+
   /// createMCInstrInfo - Create a MCInstrInfo implementation.
   ///
   MCInstrInfo *createMCInstrInfo() const {
     if (!MCInstrInfoCtorFn)
       return nullptr;
     return MCInstrInfoCtorFn();
   }
 
struct TargetRegistry {
   /// this is done by initializing all targets at program startup.
   ///
   /// @param T - The target being registered.
   /// @param Fn - A function to construct a MCAsmInfo for the target.
   static void RegisterMCAsmInfo(Target &T, Target::MCAsmInfoCtorFnTy Fn) {
     T.MCAsmInfoCtorFn = Fn;
   }
 
+  /// RegisterMCObjectFileInfo - Register a MCObjectFileInfo implementation for
+  /// the given target.
+  ///
+  /// Clients are responsible for ensuring that registration doesn't occur
+  /// while another thread is attempting to access the registry. Typically
+  /// this is done by initializing all targets at program startup.
+  ///
+  /// @param T - The target being registered.
+  /// @param Fn - A function to construct a MCObjectFileInfo for the target.
+  static void RegisterMCObjectFileInfo(Target &T,
+                                       Target::MCObjectFileInfoCtorFnTy Fn) {
+    T.MCObjectFileInfoCtorFn = Fn;
+  }
+
   /// RegisterMCInstrInfo - Register a MCInstrInfo implementation for the
   /// given target.
   ///
   /// Clients are responsible for ensuring that registration doesn't occur
   /// while another thread is attempting to access the registry. Typically
   /// this is done by initializing all targets at program startup.
   ///
   /// @param T - The target being registered.

 ///   RegisterMCAsmInfoFn X(TheFooTarget, TheFunction);
 /// }
 struct RegisterMCAsmInfoFn {
   RegisterMCAsmInfoFn(Target &T, Target::MCAsmInfoCtorFnTy Fn) {
     TargetRegistry::RegisterMCAsmInfo(T, Fn);
   }
 };
 
+/// RegisterMCObjectFileInfo - Helper template for registering a target object
+/// file info implementation.  This invokes the static "Create" method on the
+/// class to actually do the construction.  Usage:
+///
+/// extern "C" void LLVMInitializeFooTarget() {
+///   extern Target TheFooTarget;
+///   RegisterMCObjectFileInfo<FooMCObjectFileInfo> X(TheFooTarget);
+/// }
+template <class MCObjectFileInfoImpl> struct RegisterMCObjectFileInfo {
+  RegisterMCObjectFileInfo(Target &T) {
+    TargetRegistry::RegisterMCObjectFileInfo(T, &Allocator);
+  }
+
+private:
+  static MCObjectFileInfo *Allocator(MCContext &Ctx, bool PIC,
+                                     bool LargeCodeModel = false) {
+    return new MCObjectFileInfoImpl(Ctx, PIC, LargeCodeModel);
+  }
+};
+
+/// RegisterMCObjectFileInfo - Helper template for registering a target object
+/// file info implementation.  This invokes the specified function to do the
+/// construction.  Usage:
+///
+/// extern "C" void LLVMInitializeFooTarget() {
+///   extern Target TheFooTarget;
+///   RegisterMCObjectFileInfoFn X(TheFooTarget, TheFunction);
+/// }
+struct RegisterMCObjectFileInfoFn {
+  RegisterMCObjectFileInfoFn(Target &T, Target::MCObjectFileInfoCtorFnTy Fn) {
+    TargetRegistry::RegisterMCObjectFileInfo(T, Fn);
+  }
+};
+
 /// RegisterMCInstrInfo - Helper template for registering a target instruction
 /// info implementation.  This invokes the static "Create" method on the class
 /// to actually do the construction.  Usage:
 ///
 /// extern "C" void LLVMInitializeFooTarget() {
 ///   extern Target TheFooTarget;
 ///   RegisterMCInstrInfo<FooMCInstrInfo> X(TheFooTarget);
 /// }

llvm/lib/DWARFLinker/DWARFStreamer.cpp

bool DwarfStreamer::init(Triple TheTriple) {
   MAI.reset(TheTarget->createMCAsmInfo(*MRI, TripleName, MCOptions));
   if (!MAI)
     return error("no asm info for target " + TripleName, Context), false;
 
   MSTI.reset(TheTarget->createMCSubtargetInfo(TripleName, "", ""));
   if (!MSTI)
     return error("no subtarget info for target " + TripleName, Context), false;
 
-  MOFI.reset(new MCObjectFileInfo);
-  MC.reset(
-      new MCContext(TheTriple, MAI.get(), MRI.get(), MOFI.get(), MSTI.get()));
-  MOFI->initMCObjectFileInfo(*MC, /*PIC=*/false);
+  MC.reset(new MCContext(TheTriple, MAI.get(), MRI.get(), /*MOFI=*/nullptr,
+                         MSTI.get()));
+  MOFI.reset(TheTarget->createMCObjectFileInfo(*MC, /*PIC=*/false));
+  MC->setObjectFileInfo(MOFI.get());
 
   MAB = TheTarget->createMCAsmBackend(*MSTI, *MRI, MCOptions);
   if (!MAB)
     return error("no asm backend for target " + TripleName, Context), false;
 
   MII.reset(TheTarget->createMCInstrInfo());
   if (!MII)
     return error("no instr info info for target " + TripleName, Context), false;

llvm/lib/MC/MCELFStreamer.cpp

void MCELFStreamer::mergeFragment(MCDataFragment *DF,
   if (DF->getSubtargetInfo() == nullptr && EF->getSubtargetInfo())
     DF->setHasInstructions(*EF->getSubtargetInfo());
   DF->getContents().append(EF->getContents().begin(), EF->getContents().end());
 }
 
 void MCELFStreamer::InitSections(bool NoExecStack) {
   MCContext &Ctx = getContext();
   SwitchSection(Ctx.getObjectFileInfo()->getTextSection());
-  emitCodeAlignment(4);
+  emitCodeAlignment(Ctx.getObjectFileInfo()->getTextSectionAlignment());
 
   if (NoExecStack)
     SwitchSection(Ctx.getAsmInfo()->getNonexecutableStackSection(Ctx));
 }
 
 void MCELFStreamer::emitLabel(MCSymbol *S, SMLoc Loc) {
   auto *Symbol = cast<MCSymbolELF>(S);
   MCObjectStreamer::emitLabel(Symbol, Loc);

llvm/lib/MC/MCObjectFileInfo.cpp

DwarfRangesSection = Ctx->getXCOFFSection(
       ".dwrnges", SectionKind::getMetadata(), /* CsectProperties */ None,
       /* MultiSymbolsAllowed */ true, ".dwrnges", XCOFF::SSUBTYP_DWRNGES);
 
   DwarfMacinfoSection = Ctx->getXCOFFSection(
       ".dwmac", SectionKind::getMetadata(), /* CsectProperties */ None,
       /* MultiSymbolsAllowed */ true, ".dwmac", XCOFF::SSUBTYP_DWMAC);
 }
 
+MCObjectFileInfo::~MCObjectFileInfo() = default;
+
 void MCObjectFileInfo::initMCObjectFileInfo(MCContext &MCCtx, bool PIC,
                                             bool LargeCodeModel) {
   PositionIndependent = PIC;
   Ctx = &MCCtx;
 
   // Common.
   CommDirectiveSupportsAlignment = true;
   SupportsWeakOmittedEHFrame = true;

llvm/lib/Object/ModuleSymbolTable.cpp

std::unique_ptr<MCSubtargetInfo> STI(
       T->createMCSubtargetInfo(TT.str(), "", ""));
   if (!STI)
     return;
 
   std::unique_ptr<MCInstrInfo> MCII(T->createMCInstrInfo());
   if (!MCII)
     return;
 
-  MCObjectFileInfo MOFI;
-  MCContext MCCtx(TT, MAI.get(), MRI.get(), &MOFI, STI.get());
-  MOFI.initMCObjectFileInfo(MCCtx, /*PIC=*/false);
-  MOFI.setSDKVersion(M.getSDKVersion());
+  MCContext MCCtx(TT, MAI.get(), MRI.get(), /*MOFI=*/nullptr, STI.get());
+  std::unique_ptr<MCObjectFileInfo> MOFI(
+      T->createMCObjectFileInfo(MCCtx, /*PIC=*/false));
+  MOFI->setSDKVersion(M.getSDKVersion());
+  MCCtx.setObjectFileInfo(MOFI.get());
   RecordStreamer Streamer(MCCtx, M);
   T->createNullTargetStreamer(Streamer);
 
   std::unique_ptr<MemoryBuffer> Buffer(MemoryBuffer::getMemBuffer(InlineAsm));
   SourceMgr SrcMgr;
   SrcMgr.AddNewSourceBuffer(std::move(Buffer), SMLoc());
   std::unique_ptr<MCAsmParser> Parser(
       createMCAsmParser(SrcMgr, MCCtx, Streamer, *MAI));

llvm/tools/llvm-dwp/llvm-dwp.cpp

int main(int argc, char **argv) {
   if (!MAI)
     return error("no asm info for target " + TripleName, Context);
 
   std::unique_ptr<MCSubtargetInfo> MSTI(
       TheTarget->createMCSubtargetInfo(TripleName, "", ""));
   if (!MSTI)
     return error("no subtarget info for target " + TripleName, Context);
 
-  MCObjectFileInfo MOFI;
-  MCContext MC(*ErrOrTriple, MAI.get(), MRI.get(), &MOFI, MSTI.get());
-  MOFI.initMCObjectFileInfo(MC, /*PIC=*/false);
+  MCContext MC(*ErrOrTriple, MAI.get(), MRI.get(), /*MOFI=*/nullptr,
+               MSTI.get());
+  std::unique_ptr<MCObjectFileInfo> MOFI(
+      TheTarget->createMCObjectFileInfo(MC, /*PIC=*/false));
+  MC.setObjectFileInfo(MOFI.get());
 
   MCTargetOptions Options;
   auto MAB = TheTarget->createMCAsmBackend(*MSTI, *MRI, Options);
   if (!MAB)
     return error("no asm backend for target " + TripleName, Context);
 
   std::unique_ptr<MCInstrInfo> MII(TheTarget->createMCInstrInfo());
   if (!MII)

llvm/tools/llvm-exegesis/lib/SnippetFile.cpp

if (std::error_code EC = BufferPtr.getError()) {
     return make_error<Failure>("cannot read snippet: " + Filename + ": " +
                                EC.message());
   }
   SourceMgr SM;
   SM.AddNewSourceBuffer(std::move(BufferPtr.get()), SMLoc());
 
   BenchmarkCode Result;
 
-  MCObjectFileInfo ObjectFileInfo;
   const TargetMachine &TM = State.getTargetMachine();
   MCContext Context(TM.getTargetTriple(), TM.getMCAsmInfo(),
-                    TM.getMCRegisterInfo(), &ObjectFileInfo,
+                    TM.getMCRegisterInfo(), /*MOFI=*/nullptr,
                     TM.getMCSubtargetInfo());
+  std::unique_ptr<MCObjectFileInfo> ObjectFileInfo(
+      TM.getTarget().createMCObjectFileInfo(Context, /*PIC=*/false));
+  Context.setObjectFileInfo(ObjectFileInfo.get());
   Context.initInlineSourceManager();
-  ObjectFileInfo.initMCObjectFileInfo(Context, /*PIC=*/false);
   BenchmarkCodeStreamer Streamer(&Context, TM.getMCRegisterInfo(), &Result);
 
   std::string Error;
   raw_string_ostream ErrorStream(Error);
   formatted_raw_ostream InstPrinterOStream(ErrorStream);
   const std::unique_ptr<MCInstPrinter> InstPrinter(
       TM.getTarget().createMCInstPrinter(
           TM.getTargetTriple(), TM.getMCAsmInfo()->getAssemblerDialect(),

llvm/tools/llvm-mc-assemble-fuzzer/llvm-mc-assemble-fuzzer.cpp

int AssembleOneInput(const uint8_t *Data, size_t Size) {
   if (!MAI) {
     errs() << "Unable to create target asm info!";
     abort();
   }
 
   std::unique_ptr<MCSubtargetInfo> STI(
       TheTarget->createMCSubtargetInfo(TripleName, MCPU, FeaturesStr));
 
-  MCObjectFileInfo MOFI;
-  MCContext Ctx(TheTriple, MAI.get(), MRI.get(), &MOFI, STI.get(), &SrcMgr);
-  static const bool UsePIC = false;
-  MOFI.initMCObjectFileInfo(Ctx, UsePIC);
+  MCContext Ctx(TheTriple, MAI.get(), MRI.get(), /*MOFI=*/nullptr, STI.get(),
+                &SrcMgr);
+  std::unique_ptr<MCObjectFileInfo> MOFI(
+      TheTarget->createMCObjectFileInfo(Ctx, /*PIC=*/false));
+  Ctx.setObjectFileInfo(MOFI.get());
 
   const unsigned OutputAsmVariant = 0;
   std::unique_ptr<MCInstrInfo> MCII(TheTarget->createMCInstrInfo());
   MCInstPrinter *IP = TheTarget->createMCInstPrinter(Triple(TripleName), OutputAsmVariant,
       *MAI, *MCII, *MRI);
   if (!IP) {
     errs()
       << "error: unable to create instruction printer for target triple '"

llvm/tools/llvm-mc/llvm-mc.cpp

int main(int argc, char **argv) {
   }
 
   std::unique_ptr<MCSubtargetInfo> STI(
       TheTarget->createMCSubtargetInfo(TripleName, MCPU, FeaturesStr));
   assert(STI && "Unable to create subtarget info!");
 
   // FIXME: This is not pretty. MCContext has a ptr to MCObjectFileInfo and
   // MCObjectFileInfo needs a MCContext reference in order to initialize itself.
-  MCObjectFileInfo MOFI;
-  MCContext Ctx(TheTriple, MAI.get(), MRI.get(), &MOFI, STI.get(), &SrcMgr,
-                &MCOptions);
-  MOFI.initMCObjectFileInfo(Ctx, PIC, LargeCodeModel);
+  MCContext Ctx(TheTriple, MAI.get(), MRI.get(), /*MOFI=*/nullptr, STI.get(),
+                &SrcMgr, &MCOptions);
+  std::unique_ptr<MCObjectFileInfo> MOFI(
+      TheTarget->createMCObjectFileInfo(Ctx, PIC, LargeCodeModel));
+  Ctx.setObjectFileInfo(MOFI.get());
 
   if (SaveTempLabels)
     Ctx.setAllowTemporaryLabels(false);
 
   Ctx.setGenDwarfForAssembly(GenDwarfForAssembly);
   // Default to 4 for dwarf version.
   unsigned DwarfVersion = MCOptions.DwarfVersion ? MCOptions.DwarfVersion : 4;
   if (DwarfVersion < 2 || DwarfVersion > 5) {

llvm/tools/llvm-mca/llvm-mca.cpp

int main(int argc, char **argv) {
   std::unique_ptr<MCRegisterInfo> MRI(TheTarget->createMCRegInfo(TripleName));
   assert(MRI && "Unable to create target register info!");
 
   MCTargetOptions MCOptions = mc::InitMCTargetOptionsFromFlags();
   std::unique_ptr<MCAsmInfo> MAI(
       TheTarget->createMCAsmInfo(*MRI, TripleName, MCOptions));
   assert(MAI && "Unable to create target asm info!");
 
-  MCObjectFileInfo MOFI;
   SourceMgr SrcMgr;
 
   // Tell SrcMgr about this buffer, which is what the parser will pick up.
   SrcMgr.AddNewSourceBuffer(std::move(*BufferPtr), SMLoc());
 
-  MCContext Ctx(TheTriple, MAI.get(), MRI.get(), &MOFI, STI.get(), &SrcMgr);
-
-  MOFI.initMCObjectFileInfo(Ctx, /*PIC=*/false);
+  MCContext Ctx(TheTriple, MAI.get(), MRI.get(), /*MOFI=*/nullptr, STI.get(),
+                &SrcMgr);
+  std::unique_ptr<MCObjectFileInfo> MOFI(
+      TheTarget->createMCObjectFileInfo(Ctx, /*PIC=*/false));
+  Ctx.setObjectFileInfo(MOFI.get());
 
   std::unique_ptr<buffer_ostream> BOS;
 
   std::unique_ptr<MCInstrInfo> MCII(TheTarget->createMCInstrInfo());
   assert(MCII && "Unable to create instruction info!");
 
   std::unique_ptr<MCInstrAnalysis> MCIA(
       TheTarget->createMCInstrAnalysis(MCII.get()));

llvm/tools/llvm-ml/llvm-ml.cpp

int main(int Argc, char **Argv) {
   MAI->setPreserveAsmComments(InputArgs.hasArg(OPT_preserve_comments));
 
   std::unique_ptr<MCSubtargetInfo> STI(TheTarget->createMCSubtargetInfo(
       TripleName, /*CPU=*/"", /*Features=*/""));
   assert(STI && "Unable to create subtarget info!");
 
   // FIXME: This is not pretty. MCContext has a ptr to MCObjectFileInfo and
   // MCObjectFileInfo needs a MCContext reference in order to initialize itself.
-  MCObjectFileInfo MOFI;
-  MCContext Ctx(TheTriple, MAI.get(), MRI.get(), &MOFI, STI.get(), &SrcMgr);
-  MOFI.initMCObjectFileInfo(Ctx, /*PIC=*/false,
-                            /*LargeCodeModel=*/true);
+  MCContext Ctx(TheTriple, MAI.get(), MRI.get(), /*MOFI=*/nullptr, STI.get(),
+                &SrcMgr);
+  std::unique_ptr<MCObjectFileInfo> MOFI(TheTarget->createMCObjectFileInfo(
+      Ctx, /*PIC=*/false, /*LargeCodeModel=*/true));
+  Ctx.setObjectFileInfo(MOFI.get());
 
   if (InputArgs.hasArg(OPT_save_temp_labels))
     Ctx.setAllowTemporaryLabels(false);
 
   // Set compilation information.
   SmallString<128> CWD;
   if (!sys::fs::current_path(CWD))
     Ctx.setCompilationDir(CWD);

llvm/tools/llvm-objdump/llvm-objdump.cpp

std::unique_ptr<const MCSubtargetInfo> STI(
       TheTarget->createMCSubtargetInfo(TripleName, MCPU, Features.getString()));
   if (!STI)
     reportError(Obj->getFileName(),
                 "no subtarget info for target " + TripleName);
   std::unique_ptr<const MCInstrInfo> MII(TheTarget->createMCInstrInfo());
   if (!MII)
     reportError(Obj->getFileName(),
                 "no instruction info for target " + TripleName);
-  MCObjectFileInfo MOFI;
-  MCContext Ctx(Triple(TripleName), AsmInfo.get(), MRI.get(), &MOFI, STI.get());
+  MCContext Ctx(Triple(TripleName), AsmInfo.get(), MRI.get(), /*MOFI=*/nullptr,
+                STI.get());
   // FIXME: for now initialize MCObjectFileInfo with default values
-  MOFI.initMCObjectFileInfo(Ctx, /*PIC=*/false);
+  std::unique_ptr<MCObjectFileInfo> MOFI(
+      TheTarget->createMCObjectFileInfo(Ctx, /*PIC=*/false));
+  Ctx.setObjectFileInfo(MOFI.get());
 
   std::unique_ptr<MCDisassembler> DisAsm(
       TheTarget->createMCDisassembler(*STI, Ctx));
   if (!DisAsm)
     reportError(Obj->getFileName(), "no disassembler for target " + TripleName);
 
   // If we have an ARM object file, we need a second disassembler, because
   // ARM CPUs have two different instruction sets: ARM mode, and Thumb mode.

llvm/tools/llvm-profgen/ProfiledBinary.cpp

STI.reset(
       TheTarget->createMCSubtargetInfo(TripleName, "", Features.getString()));
   if (!STI)
     exitWithError("no subtarget info for target " + TripleName, FileName);
 
   MII.reset(TheTarget->createMCInstrInfo());
   if (!MII)
     exitWithError("no instruction info for target " + TripleName, FileName);
 
-  MCObjectFileInfo MOFI;
-  MCContext Ctx(Triple(TripleName), AsmInfo.get(), MRI.get(), &MOFI, STI.get());
-  MOFI.initMCObjectFileInfo(Ctx, /*PIC=*/false);
+  MCContext Ctx(Triple(TripleName), AsmInfo.get(), MRI.get(), /*MOFI=*/nullptr,
+                STI.get());
+  std::unique_ptr<MCObjectFileInfo> MOFI(
+      TheTarget->createMCObjectFileInfo(Ctx, /*PIC=*/false));
+  Ctx.setObjectFileInfo(MOFI.get());
   DisAsm.reset(TheTarget->createMCDisassembler(*STI, Ctx));
   if (!DisAsm)
     exitWithError("no disassembler for target " + TripleName, FileName);
 
   MIA.reset(TheTarget->createMCInstrAnalysis(MII.get()));
 
   int AsmPrinterVariant = AsmInfo->getAssemblerDialect();
   IPrinter.reset(TheTarget->createMCInstPrinter(

llvm/unittests/MC/SystemZ/SystemZAsmLexerTest.cpp

static void SetUpTestCase() {
     LLVMInitializeSystemZTargetInfo();
     LLVMInitializeSystemZTargetMC();
     LLVMInitializeSystemZAsmParser();
   }
 
   std::unique_ptr<MCRegisterInfo> MRI;
   std::unique_ptr<MockedUpMCAsmInfo> MUPMAI;
   std::unique_ptr<const MCInstrInfo> MII;
+  std::unique_ptr<MCObjectFileInfo> MOFI;
   std::unique_ptr<MCStreamer> Str;
   std::unique_ptr<MCAsmParser> Parser;
   std::unique_ptr<MCContext> Ctx;
   std::unique_ptr<MCSubtargetInfo> STI;
   std::unique_ptr<MCTargetAsmParser> TargetAsmParser;
 
   SourceMgr SrcMgr;
   std::string TripleName;
   llvm::Triple Triple;
   const Target *TheTarget;
 
   const MCTargetOptions MCOptions;
-  MCObjectFileInfo MOFI;
 
   SystemZAsmLexerTest() {
     // We will use the SystemZ triple, because of missing
     // Object File and Streamer support for the z/OS target.
     TripleName = "s390x-ibm-linux";
     Triple = llvm::Triple(TripleName);
 
     std::string Error;
SystemZAsmLexerTest() {
     EXPECT_EQ(MAI, nullptr);
   }
 
   void setupCallToAsmParser(StringRef AsmStr) {
     std::unique_ptr<MemoryBuffer> Buffer(MemoryBuffer::getMemBuffer(AsmStr));
     SrcMgr.AddNewSourceBuffer(std::move(Buffer), SMLoc());
     EXPECT_EQ(Buffer, nullptr);
 
-    Ctx.reset(new MCContext(Triple, MUPMAI.get(), MRI.get(), &MOFI, STI.get(),
-                            &SrcMgr, &MCOptions));
-    MOFI.initMCObjectFileInfo(*Ctx, /*PIC=*/false, /*LargeCodeModel=*/false);
+    Ctx.reset(new MCContext(Triple, MUPMAI.get(), MRI.get(), /*MOFI=*/nullptr,
+                            STI.get(), &SrcMgr, &MCOptions));
+    MOFI.reset(TheTarget->createMCObjectFileInfo(*Ctx, /*PIC=*/false,
+                                                 /*LargeCodeModel=*/false));
+    Ctx->setObjectFileInfo(MOFI.get());
 
     Str.reset(TheTarget->createNullStreamer(*Ctx));
 
     Parser.reset(createMCAsmParser(SrcMgr, *Ctx, *Str, *MUPMAI));
 
     TargetAsmParser.reset(
         TheTarget->createMCAsmParser(*STI, *Parser, *MII, MCOptions));
     Parser->setTargetParser(*TargetAsmParser);

mlir/lib/Dialect/GPU/Transforms/SerializeToHsaco.cpp

SerializeToHsacoPass::assembleIsa(const std::string &isa) {
 
   const llvm::MCTargetOptions mcOptions;
   std::unique_ptr<llvm::MCRegisterInfo> mri(
       target->createMCRegInfo(this->triple));
   std::unique_ptr<llvm::MCAsmInfo> mai(
       target->createMCAsmInfo(*mri, this->triple, mcOptions));
   mai->setRelaxELFRelocations(true);
 
-  llvm::MCObjectFileInfo mofi;
-  llvm::MCContext ctx(triple, mai.get(), mri.get(), &mofi, &srcMgr, &mcOptions);
-  mofi.initMCObjectFileInfo(ctx, /*PIC=*/false, /*LargeCodeModel=*/false);
+  llvm::MCContext ctx(triple, mai.get(), mri.get(), /*MOFI=*/nullptr, &srcMgr,
+                      &mcOptions);
+  std::unique_ptr<llvm::MCObjectFileInfo> mofi(target->createMCObjectFileInfo(
+      ctx, /*PIC=*/false, /*LargeCodeModel=*/false));
+  ctx.setObjectFileInfo(mofi.get());
 
   SmallString<128> cwd;
   if (!llvm::sys::fs::current_path(cwd))
     ctx.setCompilationDir(cwd);
 
   std::unique_ptr<llvm::MCStreamer> mcStreamer;
   std::unique_ptr<llvm::MCInstrInfo> mcii(target->createMCInstrInfo());
   std::unique_ptr<llvm::MCSubtargetInfo> sti(