Merge "Update prebuilt Clang to r353983." into p9.0HEADp9.0-backupp9.0

1 files changed, 1012 insertions, 0 deletions

diff --git a/clang-r353983/include/llvm/MC/MCStreamer.h b/clang-r353983/include/llvm/MC/MCStreamer.h
new file mode 100644
index 00000000..dc2386fc
--- /dev/null
+++ b/clang-r353983/include/llvm/MC/MCStreamer.h
@@ -0,0 +1,1012 @@
+//===- MCStreamer.h - High-level Streaming Machine Code Output --*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file declares the MCStreamer class.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_MC_MCSTREAMER_H
+#define LLVM_MC_MCSTREAMER_H
+
+#include "llvm/ADT/ArrayRef.h"
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/Optional.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/MC/MCDirectives.h"
+#include "llvm/MC/MCDwarf.h"
+#include "llvm/MC/MCLinkerOptimizationHint.h"
+#include "llvm/MC/MCSymbol.h"
+#include "llvm/MC/MCWinEH.h"
+#include "llvm/Support/Error.h"
+#include "llvm/Support/MD5.h"
+#include "llvm/Support/SMLoc.h"
+#include "llvm/Support/TargetParser.h"
+#include "llvm/Support/VersionTuple.h"
+#include <cassert>
+#include <cstdint>
+#include <memory>
+#include <string>
+#include <utility>
+#include <vector>
+
+namespace llvm {
+
+class AssemblerConstantPools;
+class formatted_raw_ostream;
+class MCAsmBackend;
+class MCCodeEmitter;
+struct MCCodePaddingContext;
+class MCContext;
+class MCExpr;
+class MCInst;
+class MCInstPrinter;
+class MCSection;
+class MCStreamer;
+class MCSymbolRefExpr;
+class MCSubtargetInfo;
+class raw_ostream;
+class Twine;
+
+using MCSectionSubPair = std::pair<MCSection *, const MCExpr *>;
+
+/// Target specific streamer interface. This is used so that targets can
+/// implement support for target specific assembly directives.
+///
+/// If target foo wants to use this, it should implement 3 classes:
+/// * FooTargetStreamer : public MCTargetStreamer
+/// * FooTargetAsmStreamer : public FooTargetStreamer
+/// * FooTargetELFStreamer : public FooTargetStreamer
+///
+/// FooTargetStreamer should have a pure virtual method for each directive. For
+/// example, for a ".bar symbol_name" directive, it should have
+/// virtual emitBar(const MCSymbol &Symbol) = 0;
+///
+/// The FooTargetAsmStreamer and FooTargetELFStreamer classes implement the
+/// method. The assembly streamer just prints ".bar symbol_name". The object
+/// streamer does whatever is needed to implement .bar in the object file.
+///
+/// In the assembly printer and parser the target streamer can be used by
+/// calling getTargetStreamer and casting it to FooTargetStreamer:
+///
+/// MCTargetStreamer &TS = OutStreamer.getTargetStreamer();
+/// FooTargetStreamer &ATS = static_cast<FooTargetStreamer &>(TS);
+///
+/// The base classes FooTargetAsmStreamer and FooTargetELFStreamer should
+/// *never* be treated differently. Callers should always talk to a
+/// FooTargetStreamer.
+class MCTargetStreamer {
+protected:
+  MCStreamer &Streamer;
+
+public:
+  MCTargetStreamer(MCStreamer &S);
+  virtual ~MCTargetStreamer();
+
+  MCStreamer &getStreamer() { return Streamer; }
+
+  // Allow a target to add behavior to the EmitLabel of MCStreamer.
+  virtual void emitLabel(MCSymbol *Symbol);
+  // Allow a target to add behavior to the emitAssignment of MCStreamer.
+  virtual void emitAssignment(MCSymbol *Symbol, const MCExpr *Value);
+
+  virtual void prettyPrintAsm(MCInstPrinter &InstPrinter, raw_ostream &OS,
+                              const MCInst &Inst, const MCSubtargetInfo &STI);
+
+  virtual void emitDwarfFileDirective(StringRef Directive);
+
+  /// Update streamer for a new active section.
+  ///
+  /// This is called by PopSection and SwitchSection, if the current
+  /// section changes.
+  virtual void changeSection(const MCSection *CurSection, MCSection *Section,
+                             const MCExpr *SubSection, raw_ostream &OS);
+
+  virtual void emitValue(const MCExpr *Value);
+
+  /// Emit the bytes in \p Data into the output.
+  ///
+  /// This is used to emit bytes in \p Data as sequence of .byte directives.
+  virtual void emitRawBytes(StringRef Data);
+
+  virtual void finish();
+};
+
+// FIXME: declared here because it is used from
+// lib/CodeGen/AsmPrinter/ARMException.cpp.
+class ARMTargetStreamer : public MCTargetStreamer {
+public:
+  ARMTargetStreamer(MCStreamer &S);
+  ~ARMTargetStreamer() override;
+
+  virtual void emitFnStart();
+  virtual void emitFnEnd();
+  virtual void emitCantUnwind();
+  virtual void emitPersonality(const MCSymbol *Personality);
+  virtual void emitPersonalityIndex(unsigned Index);
+  virtual void emitHandlerData();
+  virtual void emitSetFP(unsigned FpReg, unsigned SpReg,
+                         int64_t Offset = 0);
+  virtual void emitMovSP(unsigned Reg, int64_t Offset = 0);
+  virtual void emitPad(int64_t Offset);
+  virtual void emitRegSave(const SmallVectorImpl<unsigned> &RegList,
+                           bool isVector);
+  virtual void emitUnwindRaw(int64_t StackOffset,
+                             const SmallVectorImpl<uint8_t> &Opcodes);
+
+  virtual void switchVendor(StringRef Vendor);
+  virtual void emitAttribute(unsigned Attribute, unsigned Value);
+  virtual void emitTextAttribute(unsigned Attribute, StringRef String);
+  virtual void emitIntTextAttribute(unsigned Attribute, unsigned IntValue,
+                                    StringRef StringValue = "");
+  virtual void emitFPU(unsigned FPU);
+  virtual void emitArch(ARM::ArchKind Arch);
+  virtual void emitArchExtension(unsigned ArchExt);
+  virtual void emitObjectArch(ARM::ArchKind Arch);
+  void emitTargetAttributes(const MCSubtargetInfo &STI);
+  virtual void finishAttributeSection();
+  virtual void emitInst(uint32_t Inst, char Suffix = '\0');
+
+  virtual void AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *SRE);
+
+  virtual void emitThumbSet(MCSymbol *Symbol, const MCExpr *Value);
+
+  void finish() override;
+
+  /// Reset any state between object emissions, i.e. the equivalent of
+  /// MCStreamer's reset method.
+  virtual void reset();
+
+  /// Callback used to implement the ldr= pseudo.
+  /// Add a new entry to the constant pool for the current section and return an
+  /// MCExpr that can be used to refer to the constant pool location.
+  const MCExpr *addConstantPoolEntry(const MCExpr *, SMLoc Loc);
+
+  /// Callback used to implemnt the .ltorg directive.
+  /// Emit contents of constant pool for the current section.
+  void emitCurrentConstantPool();
+
+private:
+  std::unique_ptr<AssemblerConstantPools> ConstantPools;
+};
+
+/// Streaming machine code generation interface.
+///
+/// This interface is intended to provide a programatic interface that is very
+/// similar to the level that an assembler .s file provides.  It has callbacks
+/// to emit bytes, handle directives, etc.  The implementation of this interface
+/// retains state to know what the current section is etc.
+///
+/// There are multiple implementations of this interface: one for writing out
+/// a .s file, and implementations that write out .o files of various formats.
+///
+class MCStreamer {
+  MCContext &Context;
+  std::unique_ptr<MCTargetStreamer> TargetStreamer;
+
+  std::vector<MCDwarfFrameInfo> DwarfFrameInfos;
+  MCDwarfFrameInfo *getCurrentDwarfFrameInfo();
+
+  /// Similar to DwarfFrameInfos, but for SEH unwind info. Chained frames may
+  /// refer to each other, so use std::unique_ptr to provide pointer stability.
+  std::vector<std::unique_ptr<WinEH::FrameInfo>> WinFrameInfos;
+
+  WinEH::FrameInfo *CurrentWinFrameInfo;
+
+  /// Tracks an index to represent the order a symbol was emitted in.
+  /// Zero means we did not emit that symbol.
+  DenseMap<const MCSymbol *, unsigned> SymbolOrdering;
+
+  /// This is stack of current and previous section values saved by
+  /// PushSection.
+  SmallVector<std::pair<MCSectionSubPair, MCSectionSubPair>, 4> SectionStack;
+
+  /// The next unique ID to use when creating a WinCFI-related section (.pdata
+  /// or .xdata). This ID ensures that we have a one-to-one mapping from
+  /// code section to unwind info section, which MSVC's incremental linker
+  /// requires.
+  unsigned NextWinCFIID = 0;
+
+  bool UseAssemblerInfoForParsing;
+
+protected:
+  MCStreamer(MCContext &Ctx);
+
+  virtual void EmitCFIStartProcImpl(MCDwarfFrameInfo &Frame);
+  virtual void EmitCFIEndProcImpl(MCDwarfFrameInfo &CurFrame);
+
+  WinEH::FrameInfo *getCurrentWinFrameInfo() {
+    return CurrentWinFrameInfo;
+  }
+
+  virtual void EmitWindowsUnwindTables();
+
+  virtual void EmitRawTextImpl(StringRef String);
+
+  /// Returns true if the the .cv_loc directive is in the right section.
+  bool checkCVLocSection(unsigned FuncId, unsigned FileNo, SMLoc Loc);
+
+public:
+  MCStreamer(const MCStreamer &) = delete;
+  MCStreamer &operator=(const MCStreamer &) = delete;
+  virtual ~MCStreamer();
+
+  void visitUsedExpr(const MCExpr &Expr);
+  virtual void visitUsedSymbol(const MCSymbol &Sym);
+
+  void setTargetStreamer(MCTargetStreamer *TS) {
+    TargetStreamer.reset(TS);
+  }
+
+  /// State management
+  ///
+  virtual void reset();
+
+  MCContext &getContext() const { return Context; }
+
+  virtual MCAssembler *getAssemblerPtr() { return nullptr; }
+
+  void setUseAssemblerInfoForParsing(bool v) { UseAssemblerInfoForParsing = v; }
+  bool getUseAssemblerInfoForParsing() { return UseAssemblerInfoForParsing; }
+
+  MCTargetStreamer *getTargetStreamer() {
+    return TargetStreamer.get();
+  }
+
+  /// When emitting an object file, create and emit a real label. When emitting
+  /// textual assembly, this should do nothing to avoid polluting our output.
+  virtual MCSymbol *EmitCFILabel();
+
+  /// Retreive the current frame info if one is available and it is not yet
+  /// closed. Otherwise, issue an error and return null.
+  WinEH::FrameInfo *EnsureValidWinFrameInfo(SMLoc Loc);
+
+  unsigned getNumFrameInfos() { return DwarfFrameInfos.size(); }
+  ArrayRef<MCDwarfFrameInfo> getDwarfFrameInfos() const {
+    return DwarfFrameInfos;
+  }
+
+  bool hasUnfinishedDwarfFrameInfo();
+
+  unsigned getNumWinFrameInfos() { return WinFrameInfos.size(); }
+  ArrayRef<std::unique_ptr<WinEH::FrameInfo>> getWinFrameInfos() const {
+    return WinFrameInfos;
+  }
+
+  void generateCompactUnwindEncodings(MCAsmBackend *MAB);
+
+  /// \name Assembly File Formatting.
+  /// @{
+
+  /// Return true if this streamer supports verbose assembly and if it is
+  /// enabled.
+  virtual bool isVerboseAsm() const { return false; }
+
+  /// Return true if this asm streamer supports emitting unformatted text
+  /// to the .s file with EmitRawText.
+  virtual bool hasRawTextSupport() const { return false; }
+
+  /// Is the integrated assembler required for this streamer to function
+  /// correctly?
+  virtual bool isIntegratedAssemblerRequired() const { return false; }
+
+  /// Add a textual comment.
+  ///
+  /// Typically for comments that can be emitted to the generated .s
+  /// file if applicable as a QoI issue to make the output of the compiler
+  /// more readable.  This only affects the MCAsmStreamer, and only when
+  /// verbose assembly output is enabled.
+  ///
+  /// If the comment includes embedded \n's, they will each get the comment
+  /// prefix as appropriate.  The added comment should not end with a \n.
+  /// By default, each comment is terminated with an end of line, i.e. the
+  /// EOL param is set to true by default. If one prefers not to end the
+  /// comment with a new line then the EOL param should be passed
+  /// with a false value.
+  virtual void AddComment(const Twine &T, bool EOL = true) {}
+
+  /// Return a raw_ostream that comments can be written to. Unlike
+  /// AddComment, you are required to terminate comments with \n if you use this
+  /// method.
+  virtual raw_ostream &GetCommentOS();
+
+  /// Print T and prefix it with the comment string (normally #) and
+  /// optionally a tab. This prints the comment immediately, not at the end of
+  /// the current line. It is basically a safe version of EmitRawText: since it
+  /// only prints comments, the object streamer ignores it instead of asserting.
+  virtual void emitRawComment(const Twine &T, bool TabPrefix = true);
+
+  /// Add explicit comment T. T is required to be a valid
+  /// comment in the output and does not need to be escaped.
+  virtual void addExplicitComment(const Twine &T);
+
+  /// Emit added explicit comments.
+  virtual void emitExplicitComments();
+
+  /// AddBlankLine - Emit a blank line to a .s file to pretty it up.
+  virtual void AddBlankLine() {}
+
+  /// @}
+
+  /// \name Symbol & Section Management
+  /// @{
+
+  /// Return the current section that the streamer is emitting code to.
+  MCSectionSubPair getCurrentSection() const {
+    if (!SectionStack.empty())
+      return SectionStack.back().first;
+    return MCSectionSubPair();
+  }
+  MCSection *getCurrentSectionOnly() const { return getCurrentSection().first; }
+
+  /// Return the previous section that the streamer is emitting code to.
+  MCSectionSubPair getPreviousSection() const {
+    if (!SectionStack.empty())
+      return SectionStack.back().second;
+    return MCSectionSubPair();
+  }
+
+  /// Returns an index to represent the order a symbol was emitted in.
+  /// (zero if we did not emit that symbol)
+  unsigned GetSymbolOrder(const MCSymbol *Sym) const {
+    return SymbolOrdering.lookup(Sym);
+  }
+
+  /// Update streamer for a new active section.
+  ///
+  /// This is called by PopSection and SwitchSection, if the current
+  /// section changes.
+  virtual void ChangeSection(MCSection *, const MCExpr *);
+
+  /// Save the current and previous section on the section stack.
+  void PushSection() {
+    SectionStack.push_back(
+        std::make_pair(getCurrentSection(), getPreviousSection()));
+  }
+
+  /// Restore the current and previous section from the section stack.
+  /// Calls ChangeSection as needed.
+  ///
+  /// Returns false if the stack was empty.
+  bool PopSection() {
+    if (SectionStack.size() <= 1)
+      return false;
+    auto I = SectionStack.end();
+    --I;
+    MCSectionSubPair OldSection = I->first;
+    --I;
+    MCSectionSubPair NewSection = I->first;
+
+    if (OldSection != NewSection)
+      ChangeSection(NewSection.first, NewSection.second);
+    SectionStack.pop_back();
+    return true;
+  }
+
+  bool SubSection(const MCExpr *Subsection) {
+    if (SectionStack.empty())
+      return false;
+
+    SwitchSection(SectionStack.back().first.first, Subsection);
+    return true;
+  }
+
+  /// Set the current section where code is being emitted to \p Section.  This
+  /// is required to update CurSection.
+  ///
+  /// This corresponds to assembler directives like .section, .text, etc.
+  virtual void SwitchSection(MCSection *Section,
+                             const MCExpr *Subsection = nullptr);
+
+  /// Set the current section where code is being emitted to \p Section.
+  /// This is required to update CurSection. This version does not call
+  /// ChangeSection.
+  void SwitchSectionNoChange(MCSection *Section,
+                             const MCExpr *Subsection = nullptr) {
+    assert(Section && "Cannot switch to a null section!");
+    MCSectionSubPair curSection = SectionStack.back().first;
+    SectionStack.back().second = curSection;
+    if (MCSectionSubPair(Section, Subsection) != curSection)
+      SectionStack.back().first = MCSectionSubPair(Section, Subsection);
+  }
+
+  /// Create the default sections and set the initial one.
+  virtual void InitSections(bool NoExecStack);
+
+  MCSymbol *endSection(MCSection *Section);
+
+  /// Sets the symbol's section.
+  ///
+  /// Each emitted symbol will be tracked in the ordering table,
+  /// so we can sort on them later.
+  void AssignFragment(MCSymbol *Symbol, MCFragment *Fragment);
+
+  /// Emit a label for \p Symbol into the current section.
+  ///
+  /// This corresponds to an assembler statement such as:
+  ///   foo:
+  ///
+  /// \param Symbol - The symbol to emit. A given symbol should only be
+  /// emitted as a label once, and symbols emitted as a label should never be
+  /// used in an assignment.
+  // FIXME: These emission are non-const because we mutate the symbol to
+  // add the section we're emitting it to later.
+  virtual void EmitLabel(MCSymbol *Symbol, SMLoc Loc = SMLoc());
+
+  virtual void EmitEHSymAttributes(const MCSymbol *Symbol, MCSymbol *EHSymbol);
+
+  /// Note in the output the specified \p Flag.
+  virtual void EmitAssemblerFlag(MCAssemblerFlag Flag);
+
+  /// Emit the given list \p Options of strings as linker
+  /// options into the output.
+  virtual void EmitLinkerOptions(ArrayRef<std::string> Kind) {}
+
+  /// Note in the output the specified region \p Kind.
+  virtual void EmitDataRegion(MCDataRegionType Kind) {}
+
+  /// Specify the Mach-O minimum deployment target version.
+  virtual void EmitVersionMin(MCVersionMinType Type, unsigned Major,
+                              unsigned Minor, unsigned Update,
+                              VersionTuple SDKVersion) {}
+
+  /// Emit/Specify Mach-O build version command.
+  /// \p Platform should be one of MachO::PlatformType.
+  virtual void EmitBuildVersion(unsigned Platform, unsigned Major,
+                                unsigned Minor, unsigned Update,
+                                VersionTuple SDKVersion) {}
+
+  void EmitVersionForTarget(const Triple &Target,
+                            const VersionTuple &SDKVersion);
+
+  /// Note in the output that the specified \p Func is a Thumb mode
+  /// function (ARM target only).
+  virtual void EmitThumbFunc(MCSymbol *Func);
+
+  /// Emit an assignment of \p Value to \p Symbol.
+  ///
+  /// This corresponds to an assembler statement such as:
+  ///  symbol = value
+  ///
+  /// The assignment generates no code, but has the side effect of binding the
+  /// value in the current context. For the assembly streamer, this prints the
+  /// binding into the .s file.
+  ///
+  /// \param Symbol - The symbol being assigned to.
+  /// \param Value - The value for the symbol.
+  virtual void EmitAssignment(MCSymbol *Symbol, const MCExpr *Value);
+
+  /// Emit an weak reference from \p Alias to \p Symbol.
+  ///
+  /// This corresponds to an assembler statement such as:
+  ///  .weakref alias, symbol
+  ///
+  /// \param Alias - The alias that is being created.
+  /// \param Symbol - The symbol being aliased.
+  virtual void EmitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol);
+
+  /// Add the given \p Attribute to \p Symbol.
+  virtual bool EmitSymbolAttribute(MCSymbol *Symbol,
+                                   MCSymbolAttr Attribute) = 0;
+
+  /// Set the \p DescValue for the \p Symbol.
+  ///
+  /// \param Symbol - The symbol to have its n_desc field set.
+  /// \param DescValue - The value to set into the n_desc field.
+  virtual void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue);
+
+  /// Start emitting COFF symbol definition
+  ///
+  /// \param Symbol - The symbol to have its External & Type fields set.
+  virtual void BeginCOFFSymbolDef(const MCSymbol *Symbol);
+
+  /// Emit the storage class of the symbol.
+  ///
+  /// \param StorageClass - The storage class the symbol should have.
+  virtual void EmitCOFFSymbolStorageClass(int StorageClass);
+
+  /// Emit the type of the symbol.
+  ///
+  /// \param Type - A COFF type identifier (see COFF::SymbolType in X86COFF.h)
+  virtual void EmitCOFFSymbolType(int Type);
+
+  /// Marks the end of the symbol definition.
+  virtual void EndCOFFSymbolDef();
+
+  virtual void EmitCOFFSafeSEH(MCSymbol const *Symbol);
+
+  /// Emits the symbol table index of a Symbol into the current section.
+  virtual void EmitCOFFSymbolIndex(MCSymbol const *Symbol);
+
+  /// Emits a COFF section index.
+  ///
+  /// \param Symbol - Symbol the section number relocation should point to.
+  virtual void EmitCOFFSectionIndex(MCSymbol const *Symbol);
+
+  /// Emits a COFF section relative relocation.
+  ///
+  /// \param Symbol - Symbol the section relative relocation should point to.
+  virtual void EmitCOFFSecRel32(MCSymbol const *Symbol, uint64_t Offset);
+
+  /// Emits a COFF image relative relocation.
+  ///
+  /// \param Symbol - Symbol the image relative relocation should point to.
+  virtual void EmitCOFFImgRel32(MCSymbol const *Symbol, int64_t Offset);
+
+  /// Emit an ELF .size directive.
+  ///
+  /// This corresponds to an assembler statement such as:
+  ///  .size symbol, expression
+  virtual void emitELFSize(MCSymbol *Symbol, const MCExpr *Value);
+
+  /// Emit an ELF .symver directive.
+  ///
+  /// This corresponds to an assembler statement such as:
+  ///  .symver _start, foo@@SOME_VERSION
+  /// \param AliasName - The versioned alias (i.e. "foo@@SOME_VERSION")
+  /// \param Aliasee - The aliased symbol (i.e. "_start")
+  virtual void emitELFSymverDirective(StringRef AliasName,
+                                      const MCSymbol *Aliasee);
+
+  /// Emit a Linker Optimization Hint (LOH) directive.
+  /// \param Args - Arguments of the LOH.
+  virtual void EmitLOHDirective(MCLOHType Kind, const MCLOHArgs &Args) {}
+
+  /// Emit a common symbol.
+  ///
+  /// \param Symbol - The common symbol to emit.
+  /// \param Size - The size of the common symbol.
+  /// \param ByteAlignment - The alignment of the symbol if
+  /// non-zero. This must be a power of 2.
+  virtual void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
+                                unsigned ByteAlignment) = 0;
+
+  /// Emit a local common (.lcomm) symbol.
+  ///
+  /// \param Symbol - The common symbol to emit.
+  /// \param Size - The size of the common symbol.
+  /// \param ByteAlignment - The alignment of the common symbol in bytes.
+  virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
+                                     unsigned ByteAlignment);
+
+  /// Emit the zerofill section and an optional symbol.
+  ///
+  /// \param Section - The zerofill section to create and or to put the symbol
+  /// \param Symbol - The zerofill symbol to emit, if non-NULL.
+  /// \param Size - The size of the zerofill symbol.
+  /// \param ByteAlignment - The alignment of the zerofill symbol if
+  /// non-zero. This must be a power of 2 on some targets.
+  virtual void EmitZerofill(MCSection *Section, MCSymbol *Symbol = nullptr,
+                            uint64_t Size = 0, unsigned ByteAlignment = 0,
+                            SMLoc Loc = SMLoc()) = 0;
+
+  /// Emit a thread local bss (.tbss) symbol.
+  ///
+  /// \param Section - The thread local common section.
+  /// \param Symbol - The thread local common symbol to emit.
+  /// \param Size - The size of the symbol.
+  /// \param ByteAlignment - The alignment of the thread local common symbol
+  /// if non-zero.  This must be a power of 2 on some targets.
+  virtual void EmitTBSSSymbol(MCSection *Section, MCSymbol *Symbol,
+                              uint64_t Size, unsigned ByteAlignment = 0);
+
+  /// @}
+  /// \name Generating Data
+  /// @{
+
+  /// Emit the bytes in \p Data into the output.
+  ///
+  /// This is used to implement assembler directives such as .byte, .ascii,
+  /// etc.
+  virtual void EmitBytes(StringRef Data);
+
+  /// Functionally identical to EmitBytes. When emitting textual assembly, this
+  /// method uses .byte directives instead of .ascii or .asciz for readability.
+  virtual void EmitBinaryData(StringRef Data);
+
+  /// Emit the expression \p Value into the output as a native
+  /// integer of the given \p Size bytes.
+  ///
+  /// This is used to implement assembler directives such as .word, .quad,
+  /// etc.
+  ///
+  /// \param Value - The value to emit.
+  /// \param Size - The size of the integer (in bytes) to emit. This must
+  /// match a native machine width.
+  /// \param Loc - The location of the expression for error reporting.
+  virtual void EmitValueImpl(const MCExpr *Value, unsigned Size,
+                             SMLoc Loc = SMLoc());
+
+  void EmitValue(const MCExpr *Value, unsigned Size, SMLoc Loc = SMLoc());
+
+  /// Special case of EmitValue that avoids the client having
+  /// to pass in a MCExpr for constant integers.
+  virtual void EmitIntValue(uint64_t Value, unsigned Size);
+
+  virtual void EmitULEB128Value(const MCExpr *Value);
+
+  virtual void EmitSLEB128Value(const MCExpr *Value);
+
+  /// Special case of EmitULEB128Value that avoids the client having to
+  /// pass in a MCExpr for constant integers.
+  void EmitULEB128IntValue(uint64_t Value);
+
+  /// Special case of EmitSLEB128Value that avoids the client having to
+  /// pass in a MCExpr for constant integers.
+  void EmitSLEB128IntValue(int64_t Value);
+
+  /// Special case of EmitValue that avoids the client having to pass in
+  /// a MCExpr for MCSymbols.
+  void EmitSymbolValue(const MCSymbol *Sym, unsigned Size,
+                       bool IsSectionRelative = false);
+
+  /// Emit the expression \p Value into the output as a dtprel
+  /// (64-bit DTP relative) value.
+  ///
+  /// This is used to implement assembler directives such as .dtpreldword on
+  /// targets that support them.
+  virtual void EmitDTPRel64Value(const MCExpr *Value);
+
+  /// Emit the expression \p Value into the output as a dtprel
+  /// (32-bit DTP relative) value.
+  ///
+  /// This is used to implement assembler directives such as .dtprelword on
+  /// targets that support them.
+  virtual void EmitDTPRel32Value(const MCExpr *Value);
+
+  /// Emit the expression \p Value into the output as a tprel
+  /// (64-bit TP relative) value.
+  ///
+  /// This is used to implement assembler directives such as .tpreldword on
+  /// targets that support them.
+  virtual void EmitTPRel64Value(const MCExpr *Value);
+
+  /// Emit the expression \p Value into the output as a tprel
+  /// (32-bit TP relative) value.
+  ///
+  /// This is used to implement assembler directives such as .tprelword on
+  /// targets that support them.
+  virtual void EmitTPRel32Value(const MCExpr *Value);
+
+  /// Emit the expression \p Value into the output as a gprel64 (64-bit
+  /// GP relative) value.
+  ///
+  /// This is used to implement assembler directives such as .gpdword on
+  /// targets that support them.
+  virtual void EmitGPRel64Value(const MCExpr *Value);
+
+  /// Emit the expression \p Value into the output as a gprel32 (32-bit
+  /// GP relative) value.
+  ///
+  /// This is used to implement assembler directives such as .gprel32 on
+  /// targets that support them.
+  virtual void EmitGPRel32Value(const MCExpr *Value);
+
+  /// Emit NumBytes bytes worth of the value specified by FillValue.
+  /// This implements directives such as '.space'.
+  void emitFill(uint64_t NumBytes, uint8_t FillValue);
+
+  /// Emit \p Size bytes worth of the value specified by \p FillValue.
+  ///
+  /// This is used to implement assembler directives such as .space or .skip.
+  ///
+  /// \param NumBytes - The number of bytes to emit.
+  /// \param FillValue - The value to use when filling bytes.
+  /// \param Loc - The location of the expression for error reporting.
+  virtual void emitFill(const MCExpr &NumBytes, uint64_t FillValue,
+                        SMLoc Loc = SMLoc());
+
+  /// Emit \p NumValues copies of \p Size bytes. Each \p Size bytes is
+  /// taken from the lowest order 4 bytes of \p Expr expression.
+  ///
+  /// This is used to implement assembler directives such as .fill.
+  ///
+  /// \param NumValues - The number of copies of \p Size bytes to emit.
+  /// \param Size - The size (in bytes) of each repeated value.
+  /// \param Expr - The expression from which \p Size bytes are used.
+  virtual void emitFill(const MCExpr &NumValues, int64_t Size, int64_t Expr,
+                        SMLoc Loc = SMLoc());
+
+  /// Emit NumBytes worth of zeros.
+  /// This function properly handles data in virtual sections.
+  void EmitZeros(uint64_t NumBytes);
+
+  /// Emit some number of copies of \p Value until the byte alignment \p
+  /// ByteAlignment is reached.
+  ///
+  /// If the number of bytes need to emit for the alignment is not a multiple
+  /// of \p ValueSize, then the contents of the emitted fill bytes is
+  /// undefined.
+  ///
+  /// This used to implement the .align assembler directive.
+  ///
+  /// \param ByteAlignment - The alignment to reach. This must be a power of
+  /// two on some targets.
+  /// \param Value - The value to use when filling bytes.
+  /// \param ValueSize - The size of the integer (in bytes) to emit for
+  /// \p Value. This must match a native machine width.
+  /// \param MaxBytesToEmit - The maximum numbers of bytes to emit, or 0. If
+  /// the alignment cannot be reached in this many bytes, no bytes are
+  /// emitted.
+  virtual void EmitValueToAlignment(unsigned ByteAlignment, int64_t Value = 0,
+                                    unsigned ValueSize = 1,
+                                    unsigned MaxBytesToEmit = 0);
+
+  /// Emit nops until the byte alignment \p ByteAlignment is reached.
+  ///
+  /// This used to align code where the alignment bytes may be executed.  This
+  /// can emit different bytes for different sizes to optimize execution.
+  ///
+  /// \param ByteAlignment - The alignment to reach. This must be a power of
+  /// two on some targets.
+  /// \param MaxBytesToEmit - The maximum numbers of bytes to emit, or 0. If
+  /// the alignment cannot be reached in this many bytes, no bytes are
+  /// emitted.
+  virtual void EmitCodeAlignment(unsigned ByteAlignment,
+                                 unsigned MaxBytesToEmit = 0);
+
+  /// Emit some number of copies of \p Value until the byte offset \p
+  /// Offset is reached.
+  ///
+  /// This is used to implement assembler directives such as .org.
+  ///
+  /// \param Offset - The offset to reach. This may be an expression, but the
+  /// expression must be associated with the current section.
+  /// \param Value - The value to use when filling bytes.
+  virtual void emitValueToOffset(const MCExpr *Offset, unsigned char Value,
+                                 SMLoc Loc);
+
+  virtual void
+  EmitCodePaddingBasicBlockStart(const MCCodePaddingContext &Context) {}
+
+  virtual void
+  EmitCodePaddingBasicBlockEnd(const MCCodePaddingContext &Context) {}
+
+  /// @}
+
+  /// Switch to a new logical file.  This is used to implement the '.file
+  /// "foo.c"' assembler directive.
+  virtual void EmitFileDirective(StringRef Filename);
+
+  /// Emit the "identifiers" directive.  This implements the
+  /// '.ident "version foo"' assembler directive.
+  virtual void EmitIdent(StringRef IdentString) {}
+
+  /// Associate a filename with a specified logical file number.  This
+  /// implements the DWARF2 '.file 4 "foo.c"' assembler directive.
+  unsigned EmitDwarfFileDirective(unsigned FileNo, StringRef Directory,
+                                  StringRef Filename,
+                                  MD5::MD5Result *Checksum = nullptr,
+                                  Optional<StringRef> Source = None,
+                                  unsigned CUID = 0) {
+    return cantFail(
+        tryEmitDwarfFileDirective(FileNo, Directory, Filename, Checksum,
+                                  Source, CUID));
+  }
+
+  /// Associate a filename with a specified logical file number.
+  /// Also associate a directory, optional checksum, and optional source
+  /// text with the logical file.  This implements the DWARF2
+  /// '.file 4 "dir/foo.c"' assembler directive, and the DWARF5
+  /// '.file 4 "dir/foo.c" md5 "..." source "..."' assembler directive.
+  virtual Expected<unsigned> tryEmitDwarfFileDirective(
+      unsigned FileNo, StringRef Directory, StringRef Filename,
+      MD5::MD5Result *Checksum = nullptr, Optional<StringRef> Source = None,
+      unsigned CUID = 0);
+
+  /// Specify the "root" file of the compilation, using the ".file 0" extension.
+  virtual void emitDwarfFile0Directive(StringRef Directory, StringRef Filename,
+                                       MD5::MD5Result *Checksum,
+                                       Optional<StringRef> Source,
+                                       unsigned CUID = 0);
+
+  virtual void EmitCFIBKeyFrame();
+
+  /// This implements the DWARF2 '.loc fileno lineno ...' assembler
+  /// directive.
+  virtual void EmitDwarfLocDirective(unsigned FileNo, unsigned Line,
+                                     unsigned Column, unsigned Flags,
+                                     unsigned Isa, unsigned Discriminator,
+                                     StringRef FileName);
+
+  /// Associate a filename with a specified logical file number, and also
+  /// specify that file's checksum information.  This implements the '.cv_file 4
+  /// "foo.c"' assembler directive. Returns true on success.
+  virtual bool EmitCVFileDirective(unsigned FileNo, StringRef Filename,
+                                   ArrayRef<uint8_t> Checksum,
+                                   unsigned ChecksumKind);
+
+  /// Introduces a function id for use with .cv_loc.
+  virtual bool EmitCVFuncIdDirective(unsigned FunctionId);
+
+  /// Introduces an inline call site id for use with .cv_loc. Includes
+  /// extra information for inline line table generation.
+  virtual bool EmitCVInlineSiteIdDirective(unsigned FunctionId, unsigned IAFunc,
+                                           unsigned IAFile, unsigned IALine,
+                                           unsigned IACol, SMLoc Loc);
+
+  /// This implements the CodeView '.cv_loc' assembler directive.
+  virtual void EmitCVLocDirective(unsigned FunctionId, unsigned FileNo,
+                                  unsigned Line, unsigned Column,
+                                  bool PrologueEnd, bool IsStmt,
+                                  StringRef FileName, SMLoc Loc);
+
+  /// This implements the CodeView '.cv_linetable' assembler directive.
+  virtual void EmitCVLinetableDirective(unsigned FunctionId,
+                                        const MCSymbol *FnStart,
+                                        const MCSymbol *FnEnd);
+
+  /// This implements the CodeView '.cv_inline_linetable' assembler
+  /// directive.
+  virtual void EmitCVInlineLinetableDirective(unsigned PrimaryFunctionId,
+                                              unsigned SourceFileId,
+                                              unsigned SourceLineNum,
+                                              const MCSymbol *FnStartSym,
+                                              const MCSymbol *FnEndSym);
+
+  /// This implements the CodeView '.cv_def_range' assembler
+  /// directive.
+  virtual void EmitCVDefRangeDirective(
+      ArrayRef<std::pair<const MCSymbol *, const MCSymbol *>> Ranges,
+      StringRef FixedSizePortion);
+
+  /// This implements the CodeView '.cv_stringtable' assembler directive.
+  virtual void EmitCVStringTableDirective() {}
+
+  /// This implements the CodeView '.cv_filechecksums' assembler directive.
+  virtual void EmitCVFileChecksumsDirective() {}
+
+  /// This implements the CodeView '.cv_filechecksumoffset' assembler
+  /// directive.
+  virtual void EmitCVFileChecksumOffsetDirective(unsigned FileNo) {}
+
+  /// This implements the CodeView '.cv_fpo_data' assembler directive.
+  virtual void EmitCVFPOData(const MCSymbol *ProcSym, SMLoc Loc = {}) {}
+
+  /// Emit the absolute difference between two symbols.
+  ///
+  /// \pre Offset of \c Hi is greater than the offset \c Lo.
+  virtual void emitAbsoluteSymbolDiff(const MCSymbol *Hi, const MCSymbol *Lo,
+                                      unsigned Size);
+
+  /// Emit the absolute difference between two symbols encoded with ULEB128.
+  virtual void emitAbsoluteSymbolDiffAsULEB128(const MCSymbol *Hi,
+                                               const MCSymbol *Lo);
+
+  virtual MCSymbol *getDwarfLineTableSymbol(unsigned CUID);
+  virtual void EmitCFISections(bool EH, bool Debug);
+  void EmitCFIStartProc(bool IsSimple, SMLoc Loc = SMLoc());
+  void EmitCFIEndProc();
+  virtual void EmitCFIDefCfa(int64_t Register, int64_t Offset);
+  virtual void EmitCFIDefCfaOffset(int64_t Offset);
+  virtual void EmitCFIDefCfaRegister(int64_t Register);
+  virtual void EmitCFIOffset(int64_t Register, int64_t Offset);
+  virtual void EmitCFIPersonality(const MCSymbol *Sym, unsigned Encoding);
+  virtual void EmitCFILsda(const MCSymbol *Sym, unsigned Encoding);
+  virtual void EmitCFIRememberState();
+  virtual void EmitCFIRestoreState();
+  virtual void EmitCFISameValue(int64_t Register);
+  virtual void EmitCFIRestore(int64_t Register);
+  virtual void EmitCFIRelOffset(int64_t Register, int64_t Offset);
+  virtual void EmitCFIAdjustCfaOffset(int64_t Adjustment);
+  virtual void EmitCFIEscape(StringRef Values);
+  virtual void EmitCFIReturnColumn(int64_t Register);
+  virtual void EmitCFIGnuArgsSize(int64_t Size);
+  virtual void EmitCFISignalFrame();
+  virtual void EmitCFIUndefined(int64_t Register);
+  virtual void EmitCFIRegister(int64_t Register1, int64_t Register2);
+  virtual void EmitCFIWindowSave();
+  virtual void EmitCFINegateRAState();
+
+  virtual void EmitWinCFIStartProc(const MCSymbol *Symbol, SMLoc Loc = SMLoc());
+  virtual void EmitWinCFIEndProc(SMLoc Loc = SMLoc());
+  /// This is used on platforms, such as Windows on ARM64, that require function
+  /// or funclet sizes to be emitted in .xdata before the End marker is emitted
+  /// for the frame.  We cannot use the End marker, as it is not set at the
+  /// point of emitting .xdata, in order to indicate that the frame is active.
+  virtual void EmitWinCFIFuncletOrFuncEnd(SMLoc Loc = SMLoc());
+  virtual void EmitWinCFIStartChained(SMLoc Loc = SMLoc());
+  virtual void EmitWinCFIEndChained(SMLoc Loc = SMLoc());
+  virtual void EmitWinCFIPushReg(unsigned Register, SMLoc Loc = SMLoc());
+  virtual void EmitWinCFISetFrame(unsigned Register, unsigned Offset,
+                                  SMLoc Loc = SMLoc());
+  virtual void EmitWinCFIAllocStack(unsigned Size, SMLoc Loc = SMLoc());
+  virtual void EmitWinCFISaveReg(unsigned Register, unsigned Offset,
+                                 SMLoc Loc = SMLoc());
+  virtual void EmitWinCFISaveXMM(unsigned Register, unsigned Offset,
+                                 SMLoc Loc = SMLoc());
+  virtual void EmitWinCFIPushFrame(bool Code, SMLoc Loc = SMLoc());
+  virtual void EmitWinCFIEndProlog(SMLoc Loc = SMLoc());
+  virtual void EmitWinEHHandler(const MCSymbol *Sym, bool Unwind, bool Except,
+                                SMLoc Loc = SMLoc());
+  virtual void EmitWinEHHandlerData(SMLoc Loc = SMLoc());
+
+  virtual void emitCGProfileEntry(const MCSymbolRefExpr *From,
+                                  const MCSymbolRefExpr *To, uint64_t Count);
+
+  /// Get the .pdata section used for the given section. Typically the given
+  /// section is either the main .text section or some other COMDAT .text
+  /// section, but it may be any section containing code.
+  MCSection *getAssociatedPDataSection(const MCSection *TextSec);
+
+  /// Get the .xdata section used for the given section.
+  MCSection *getAssociatedXDataSection(const MCSection *TextSec);
+
+  virtual void EmitSyntaxDirective();
+
+  /// Emit a .reloc directive.
+  /// Returns true if the relocation could not be emitted because Name is not
+  /// known.
+  virtual bool EmitRelocDirective(const MCExpr &Offset, StringRef Name,
+                                  const MCExpr *Expr, SMLoc Loc,
+                                  const MCSubtargetInfo &STI) {
+    return true;
+  }
+
+  virtual void EmitAddrsig() {}
+  virtual void EmitAddrsigSym(const MCSymbol *Sym) {}
+
+  /// Emit the given \p Instruction into the current section.
+  virtual void EmitInstruction(const MCInst &Inst, const MCSubtargetInfo &STI);
+
+  /// Set the bundle alignment mode from now on in the section.
+  /// The argument is the power of 2 to which the alignment is set. The
+  /// value 0 means turn the bundle alignment off.
+  virtual void EmitBundleAlignMode(unsigned AlignPow2);
+
+  /// The following instructions are a bundle-locked group.
+  ///
+  /// \param AlignToEnd - If true, the bundle-locked group will be aligned to
+  ///                     the end of a bundle.
+  virtual void EmitBundleLock(bool AlignToEnd);
+
+  /// Ends a bundle-locked group.
+  virtual void EmitBundleUnlock();
+
+  /// If this file is backed by a assembly streamer, this dumps the
+  /// specified string in the output .s file.  This capability is indicated by
+  /// the hasRawTextSupport() predicate.  By default this aborts.
+  void EmitRawText(const Twine &String);
+
+  /// Streamer specific finalization.
+  virtual void FinishImpl();
+  /// Finish emission of machine code.
+  void Finish();
+
+  virtual bool mayHaveInstructions(MCSection &Sec) const { return true; }
+};
+
+/// Create a dummy machine code streamer, which does nothing. This is useful for
+/// timing the assembler front end.
+MCStreamer *createNullStreamer(MCContext &Ctx);
+
+/// Create a machine code streamer which will print out assembly for the native
+/// target, suitable for compiling with a native assembler.
+///
+/// \param InstPrint - If given, the instruction printer to use. If not given
+/// the MCInst representation will be printed.  This method takes ownership of
+/// InstPrint.
+///
+/// \param CE - If given, a code emitter to use to show the instruction
+/// encoding inline with the assembly. This method takes ownership of \p CE.
+///
+/// \param TAB - If given, a target asm backend to use to show the fixup
+/// information in conjunction with encoding information. This method takes
+/// ownership of \p TAB.
+///
+/// \param ShowInst - Whether to show the MCInst representation inline with
+/// the assembly.
+MCStreamer *createAsmStreamer(MCContext &Ctx,
+                              std::unique_ptr<formatted_raw_ostream> OS,
+                              bool isVerboseAsm, bool useDwarfDirectory,
+                              MCInstPrinter *InstPrint, MCCodeEmitter *CE,
+                              MCAsmBackend *TAB, bool ShowInst);
+
+} // end namespace llvm
+
+#endif // LLVM_MC_MCSTREAMER_H