include/llvm/MC/MCContext.h - llvm - Git at Google

 //===- MCContext.h - Machine Code Context -----------------------*- C++ -*-===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//

 #ifndef LLVM_MC_MCCONTEXT_H
 #define LLVM_MC_MCCONTEXT_H

 #include "llvm/ADT/DenseMap.h"
 #include "llvm/ADT/SetVector.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/SmallVector.h"
 #include "llvm/ADT/StringMap.h"
 #include "llvm/ADT/Twine.h"
 #include "llvm/MC/MCDwarf.h"
 #include "llvm/MC/SectionKind.h"
 #include "llvm/Support/Allocator.h"
 #include "llvm/Support/Compiler.h"
 #include "llvm/Support/raw_ostream.h"
 #include <map>
 #include <tuple>
 #include <vector> // FIXME: Shouldn't be needed.

 namespace llvm {
   class MCAsmInfo;
   class MCExpr;
   class MCSection;
   class MCSymbol;
   class MCSymbolELF;
   class MCLabel;
   struct MCDwarfFile;
   class MCDwarfLoc;
   class MCObjectFileInfo;
   class MCRegisterInfo;
   class MCLineSection;
   class SMLoc;
   class MCSectionMachO;
   class MCSectionELF;
   class MCSectionCOFF;

   /// Context object for machine code objects.  This class owns all of the
   /// sections that it creates.
   ///
   class MCContext {
     MCContext(const MCContext &) = delete;
     MCContext &operator=(const MCContext &) = delete;

   public:
     typedef StringMap<MCSymbol *, BumpPtrAllocator &> SymbolTable;

   private:
     /// The SourceMgr for this object, if any.
     const SourceMgr *SrcMgr;

     /// The MCAsmInfo for this target.
     const MCAsmInfo *MAI;

     /// The MCRegisterInfo for this target.
     const MCRegisterInfo *MRI;

     /// The MCObjectFileInfo for this target.
     const MCObjectFileInfo *MOFI;

     /// Allocator object used for creating machine code objects.
     ///
     /// We use a bump pointer allocator to avoid the need to track all allocated
     /// objects.
     BumpPtrAllocator Allocator;

     /// Bindings of names to symbols.
     SymbolTable Symbols;

     /// ELF sections can have a corresponding symbol. This maps one to the
     /// other.
     DenseMap<const MCSectionELF *, MCSymbolELF *> SectionSymbols;

     /// A mapping from a local label number and an instance count to a symbol.
     /// For example, in the assembly
     ///     1:
     ///     2:
     ///     1:
     /// We have three labels represented by the pairs (1, 0), (2, 0) and (1, 1)
     DenseMap<std::pair<unsigned, unsigned>, MCSymbol *> LocalSymbols;

     /// Keeps tracks of names that were used both for used declared and
     /// artificial symbols.
     StringMap<bool, BumpPtrAllocator &> UsedNames;

     /// The next ID to dole out to an unnamed assembler temporary symbol with
     /// a given prefix.
     StringMap<unsigned> NextID;

     /// Instances of directional local labels.
     DenseMap<unsigned, MCLabel *> Instances;
     /// NextInstance() creates the next instance of the directional local label
     /// for the LocalLabelVal and adds it to the map if needed.
     unsigned NextInstance(unsigned LocalLabelVal);
     /// GetInstance() gets the current instance of the directional local label
     /// for the LocalLabelVal and adds it to the map if needed.
     unsigned GetInstance(unsigned LocalLabelVal);

     /// The file name of the log file from the environment variable
     /// AS_SECURE_LOG_FILE.  Which must be set before the .secure_log_unique
     /// directive is used or it is an error.
     char *SecureLogFile;
     /// The stream that gets written to for the .secure_log_unique directive.
     raw_ostream *SecureLog;
     /// Boolean toggled when .secure_log_unique / .secure_log_reset is seen to
     /// catch errors if .secure_log_unique appears twice without
     /// .secure_log_reset appearing between them.
     bool SecureLogUsed;

     /// The compilation directory to use for DW_AT_comp_dir.
     SmallString<128> CompilationDir;

     /// The main file name if passed in explicitly.
     std::string MainFileName;

     /// The dwarf file and directory tables from the dwarf .file directive.
     /// We now emit a line table for each compile unit. To reduce the prologue
     /// size of each line table, the files and directories used by each compile
     /// unit are separated.
     std::map<unsigned, MCDwarfLineTable> MCDwarfLineTablesCUMap;

     /// The current dwarf line information from the last dwarf .loc directive.
     MCDwarfLoc CurrentDwarfLoc;
     bool DwarfLocSeen;

     /// Generate dwarf debugging info for assembly source files.
     bool GenDwarfForAssembly;

     /// The current dwarf file number when generate dwarf debugging info for
     /// assembly source files.
     unsigned GenDwarfFileNumber;

     /// Sections for generating the .debug_ranges and .debug_aranges sections.
     SetVector<MCSection *> SectionsForRanges;

     /// The information gathered from labels that will have dwarf label
     /// entries when generating dwarf assembly source files.
     std::vector<MCGenDwarfLabelEntry> MCGenDwarfLabelEntries;

     /// The string to embed in the debug information for the compile unit, if
     /// non-empty.
     StringRef DwarfDebugFlags;

     /// The string to embed in as the dwarf AT_producer for the compile unit, if
     /// non-empty.
     StringRef DwarfDebugProducer;

     /// The maximum version of dwarf that we should emit.
     uint16_t DwarfVersion;

     /// Honor temporary labels, this is useful for debugging semantic
     /// differences between temporary and non-temporary labels (primarily on
     /// Darwin).
     bool AllowTemporaryLabels;
     bool UseNamesOnTempLabels = true;

     /// The Compile Unit ID that we are currently processing.
     unsigned DwarfCompileUnitID;

     struct ELFSectionKey {
       std::string SectionName;
       StringRef GroupName;
       unsigned UniqueID;
       ELFSectionKey(StringRef SectionName, StringRef GroupName,
                     unsigned UniqueID)
           : SectionName(SectionName), GroupName(GroupName), UniqueID(UniqueID) {
       }
       bool operator<(const ELFSectionKey &Other) const {
         if (SectionName != Other.SectionName)
           return SectionName < Other.SectionName;
         if (GroupName != Other.GroupName)
           return GroupName < Other.GroupName;
         return UniqueID < Other.UniqueID;
       }
     };

     struct COFFSectionKey {
       std::string SectionName;
       StringRef GroupName;
       int SelectionKey;
       COFFSectionKey(StringRef SectionName, StringRef GroupName,
                      int SelectionKey)
           : SectionName(SectionName), GroupName(GroupName),
             SelectionKey(SelectionKey) {}
       bool operator<(const COFFSectionKey &Other) const {
         if (SectionName != Other.SectionName)
           return SectionName < Other.SectionName;
         if (GroupName != Other.GroupName)
           return GroupName < Other.GroupName;
         return SelectionKey < Other.SelectionKey;
       }
     };

     StringMap<MCSectionMachO *> MachOUniquingMap;
     std::map<ELFSectionKey, MCSectionELF *> ELFUniquingMap;
     std::map<COFFSectionKey, MCSectionCOFF *> COFFUniquingMap;
     StringMap<bool> ELFRelSecNames;

     /// Do automatic reset in destructor
     bool AutoReset;

     MCSymbol *createSymbolImpl(const StringMapEntry<bool> *Name,
                                bool CanBeUnnamed);
     MCSymbol *createSymbol(StringRef Name, bool AlwaysAddSuffix,
                            bool IsTemporary);

     MCSymbol *getOrCreateDirectionalLocalSymbol(unsigned LocalLabelVal,
                                                 unsigned Instance);

   public:
     explicit MCContext(const MCAsmInfo *MAI, const MCRegisterInfo *MRI,
                        const MCObjectFileInfo *MOFI,
                        const SourceMgr *Mgr = nullptr, bool DoAutoReset = true);
     ~MCContext();

     const SourceMgr *getSourceManager() const { return SrcMgr; }

     const MCAsmInfo *getAsmInfo() const { return MAI; }

     const MCRegisterInfo *getRegisterInfo() const { return MRI; }

     const MCObjectFileInfo *getObjectFileInfo() const { return MOFI; }

     void setAllowTemporaryLabels(bool Value) { AllowTemporaryLabels = Value; }
     void setUseNamesOnTempLabels(bool Value) { UseNamesOnTempLabels = Value; }

     /// \name Module Lifetime Management
     /// @{

     /// reset - return object to right after construction state to prepare
     /// to process a new module
     void reset();

     /// @}

     /// \name Symbol Management
     /// @{

     /// Create and return a new linker temporary symbol with a unique but
     /// unspecified name.
     MCSymbol *createLinkerPrivateTempSymbol();

     /// Create and return a new assembler temporary symbol with a unique but
     /// unspecified name.
     MCSymbol *createTempSymbol(bool CanBeUnnamed = true);

     MCSymbol *createTempSymbol(const Twine &Name, bool AlwaysAddSuffix,
                                bool CanBeUnnamed = true);

     /// Create the definition of a directional local symbol for numbered label
     /// (used for "1:" definitions).
     MCSymbol *createDirectionalLocalSymbol(unsigned LocalLabelVal);

     /// Create and return a directional local symbol for numbered label (used
     /// for "1b" or 1f" references).
     MCSymbol *getDirectionalLocalSymbol(unsigned LocalLabelVal, bool Before);

     /// Lookup the symbol inside with the specified \p Name.  If it exists,
     /// return it.  If not, create a forward reference and return it.
     ///
     /// \param Name - The symbol name, which must be unique across all symbols.
     MCSymbol *getOrCreateSymbol(const Twine &Name);

     MCSymbolELF *getOrCreateSectionSymbol(const MCSectionELF &Section);

     /// Gets a symbol that will be defined to the final stack offset of a local
     /// variable after codegen.
     ///
     /// \param Idx - The index of a local variable passed to @llvm.localescape.
     MCSymbol *getOrCreateFrameAllocSymbol(StringRef FuncName, unsigned Idx);

     MCSymbol *getOrCreateParentFrameOffsetSymbol(StringRef FuncName);

     MCSymbol *getOrCreateLSDASymbol(StringRef FuncName);

     /// Get the symbol for \p Name, or null.
     MCSymbol *lookupSymbol(const Twine &Name) const;

     /// getSymbols - Get a reference for the symbol table for clients that
     /// want to, for example, iterate over all symbols. 'const' because we
     /// still want any modifications to the table itself to use the MCContext
     /// APIs.
     const SymbolTable &getSymbols() const { return Symbols; }

     /// @}

     /// \name Section Management
     /// @{

     /// Return the MCSection for the specified mach-o section.  This requires
     /// the operands to be valid.
     MCSectionMachO *getMachOSection(StringRef Segment, StringRef Section,
                                     unsigned TypeAndAttributes,
                                     unsigned Reserved2, SectionKind K,
                                     const char *BeginSymName = nullptr);

     MCSectionMachO *getMachOSection(StringRef Segment, StringRef Section,
                                     unsigned TypeAndAttributes, SectionKind K,
                                     const char *BeginSymName = nullptr) {
       return getMachOSection(Segment, Section, TypeAndAttributes, 0, K,
                              BeginSymName);
     }

     MCSectionELF *getELFSection(StringRef Section, unsigned Type,
                                 unsigned Flags) {
       return getELFSection(Section, Type, Flags, nullptr);
     }

     MCSectionELF *getELFSection(StringRef Section, unsigned Type,
                                 unsigned Flags, const char *BeginSymName) {
       return getELFSection(Section, Type, Flags, 0, "", BeginSymName);
     }

     MCSectionELF *getELFSection(StringRef Section, unsigned Type,
                                 unsigned Flags, unsigned EntrySize,
                                 StringRef Group) {
       return getELFSection(Section, Type, Flags, EntrySize, Group, nullptr);
     }

     MCSectionELF *getELFSection(StringRef Section, unsigned Type,
                                 unsigned Flags, unsigned EntrySize,
                                 StringRef Group, const char *BeginSymName) {
       return getELFSection(Section, Type, Flags, EntrySize, Group, ~0,
                            BeginSymName);
     }

     MCSectionELF *getELFSection(StringRef Section, unsigned Type,
                                 unsigned Flags, unsigned EntrySize,
                                 StringRef Group, unsigned UniqueID) {
       return getELFSection(Section, Type, Flags, EntrySize, Group, UniqueID,
                            nullptr);
     }

     MCSectionELF *getELFSection(StringRef Section, unsigned Type,
                                 unsigned Flags, unsigned EntrySize,
                                 StringRef Group, unsigned UniqueID,
                                 const char *BeginSymName);

     MCSectionELF *getELFSection(StringRef Section, unsigned Type,
                                 unsigned Flags, unsigned EntrySize,
                                 const MCSymbolELF *Group, unsigned UniqueID,
                                 const char *BeginSymName,
                                 const MCSectionELF *Associated);

     MCSectionELF *createELFRelSection(StringRef Name, unsigned Type,
                                       unsigned Flags, unsigned EntrySize,
                                       const MCSymbolELF *Group,
                                       const MCSectionELF *Associated);

     void renameELFSection(MCSectionELF *Section, StringRef Name);

     MCSectionELF *createELFGroupSection(const MCSymbolELF *Group);

     MCSectionCOFF *getCOFFSection(StringRef Section, unsigned Characteristics,
                                   SectionKind Kind, StringRef COMDATSymName,
                                   int Selection,
                                   const char *BeginSymName = nullptr);

     MCSectionCOFF *getCOFFSection(StringRef Section, unsigned Characteristics,
                                   SectionKind Kind,
                                   const char *BeginSymName = nullptr);

     MCSectionCOFF *getCOFFSection(StringRef Section);

     /// Gets or creates a section equivalent to Sec that is associated with the
     /// section containing KeySym. For example, to create a debug info section
     /// associated with an inline function, pass the normal debug info section
     /// as Sec and the function symbol as KeySym.
     MCSectionCOFF *getAssociativeCOFFSection(MCSectionCOFF *Sec,
                                              const MCSymbol *KeySym);

     /// @}

     /// \name Dwarf Management
     /// @{

     /// \brief Get the compilation directory for DW_AT_comp_dir
     /// This can be overridden by clients which want to control the reported
     /// compilation directory and have it be something other than the current
     /// working directory.
     /// Returns an empty string if the current directory cannot be determined.
     StringRef getCompilationDir() const { return CompilationDir; }

     /// \brief Set the compilation directory for DW_AT_comp_dir
     /// Override the default (CWD) compilation directory.
     void setCompilationDir(StringRef S) { CompilationDir = S.str(); }

     /// \brief Get the main file name for use in error messages and debug
     /// info. This can be set to ensure we've got the correct file name
     /// after preprocessing or for -save-temps.
     const std::string &getMainFileName() const { return MainFileName; }

     /// \brief Set the main file name and override the default.
     void setMainFileName(StringRef S) { MainFileName = S; }

     /// Creates an entry in the dwarf file and directory tables.
     unsigned getDwarfFile(StringRef Directory, StringRef FileName,
                           unsigned FileNumber, unsigned CUID);

     bool isValidDwarfFileNumber(unsigned FileNumber, unsigned CUID = 0);

     const std::map<unsigned, MCDwarfLineTable> &getMCDwarfLineTables() const {
       return MCDwarfLineTablesCUMap;
     }

     MCDwarfLineTable &getMCDwarfLineTable(unsigned CUID) {
       return MCDwarfLineTablesCUMap[CUID];
     }

     const MCDwarfLineTable &getMCDwarfLineTable(unsigned CUID) const {
       auto I = MCDwarfLineTablesCUMap.find(CUID);
       assert(I != MCDwarfLineTablesCUMap.end());
       return I->second;
     }

     const SmallVectorImpl<MCDwarfFile> &getMCDwarfFiles(unsigned CUID = 0) {
       return getMCDwarfLineTable(CUID).getMCDwarfFiles();
     }
     const SmallVectorImpl<std::string> &getMCDwarfDirs(unsigned CUID = 0) {
       return getMCDwarfLineTable(CUID).getMCDwarfDirs();
     }

     bool hasMCLineSections() const {
       for (const auto &Table : MCDwarfLineTablesCUMap)
         if (!Table.second.getMCDwarfFiles().empty() || Table.second.getLabel())
           return true;
       return false;
     }
     unsigned getDwarfCompileUnitID() { return DwarfCompileUnitID; }
     void setDwarfCompileUnitID(unsigned CUIndex) {
       DwarfCompileUnitID = CUIndex;
     }
     void setMCLineTableCompilationDir(unsigned CUID, StringRef CompilationDir) {
       getMCDwarfLineTable(CUID).setCompilationDir(CompilationDir);
     }

     /// Saves the information from the currently parsed dwarf .loc directive
     /// and sets DwarfLocSeen.  When the next instruction is assembled an entry
     /// in the line number table with this information and the address of the
     /// instruction will be created.
     void setCurrentDwarfLoc(unsigned FileNum, unsigned Line, unsigned Column,
                             unsigned Flags, unsigned Isa,
                             unsigned Discriminator) {
       CurrentDwarfLoc.setFileNum(FileNum);
       CurrentDwarfLoc.setLine(Line);
       CurrentDwarfLoc.setColumn(Column);
       CurrentDwarfLoc.setFlags(Flags);
       CurrentDwarfLoc.setIsa(Isa);
       CurrentDwarfLoc.setDiscriminator(Discriminator);
       DwarfLocSeen = true;
     }
     void clearDwarfLocSeen() { DwarfLocSeen = false; }

     bool getDwarfLocSeen() { return DwarfLocSeen; }
     const MCDwarfLoc &getCurrentDwarfLoc() { return CurrentDwarfLoc; }

     bool getGenDwarfForAssembly() { return GenDwarfForAssembly; }
     void setGenDwarfForAssembly(bool Value) { GenDwarfForAssembly = Value; }
     unsigned getGenDwarfFileNumber() { return GenDwarfFileNumber; }
     void setGenDwarfFileNumber(unsigned FileNumber) {
       GenDwarfFileNumber = FileNumber;
     }
     const SetVector<MCSection *> &getGenDwarfSectionSyms() {
       return SectionsForRanges;
     }
     bool addGenDwarfSection(MCSection *Sec) {
       return SectionsForRanges.insert(Sec);
     }

     void finalizeDwarfSections(MCStreamer &MCOS);
     const std::vector<MCGenDwarfLabelEntry> &getMCGenDwarfLabelEntries() const {
       return MCGenDwarfLabelEntries;
     }
     void addMCGenDwarfLabelEntry(const MCGenDwarfLabelEntry &E) {
       MCGenDwarfLabelEntries.push_back(E);
     }

     void setDwarfDebugFlags(StringRef S) { DwarfDebugFlags = S; }
     StringRef getDwarfDebugFlags() { return DwarfDebugFlags; }

     void setDwarfDebugProducer(StringRef S) { DwarfDebugProducer = S; }
     StringRef getDwarfDebugProducer() { return DwarfDebugProducer; }

     void setDwarfVersion(uint16_t v) { DwarfVersion = v; }
     uint16_t getDwarfVersion() const { return DwarfVersion; }

     /// @}

     char *getSecureLogFile() { return SecureLogFile; }
     raw_ostream *getSecureLog() { return SecureLog; }
     bool getSecureLogUsed() { return SecureLogUsed; }
     void setSecureLog(raw_ostream *Value) { SecureLog = Value; }
     void setSecureLogUsed(bool Value) { SecureLogUsed = Value; }

     void *allocate(unsigned Size, unsigned Align = 8) {
       return Allocator.Allocate(Size, Align);
     }
     void deallocate(void *Ptr) {}

     // Unrecoverable error has occurred. Display the best diagnostic we can
     // and bail via exit(1). For now, most MC backend errors are unrecoverable.
     // FIXME: We should really do something about that.
     LLVM_ATTRIBUTE_NORETURN void reportFatalError(SMLoc L,
                                                   const Twine &Msg) const;
   };

 } // end namespace llvm

 // operator new and delete aren't allowed inside namespaces.
 // The throw specifications are mandated by the standard.
 /// \brief Placement new for using the MCContext's allocator.
 ///
 /// This placement form of operator new uses the MCContext's allocator for
 /// obtaining memory. It is a non-throwing new, which means that it returns
 /// null on error. (If that is what the allocator does. The current does, so if
 /// this ever changes, this operator will have to be changed, too.)
 /// Usage looks like this (assuming there's an MCContext 'Context' in scope):
 /// \code
 /// // Default alignment (8)
 /// IntegerLiteral *Ex = new (Context) IntegerLiteral(arguments);
 /// // Specific alignment
 /// IntegerLiteral *Ex2 = new (Context, 4) IntegerLiteral(arguments);
 /// \endcode
 /// Please note that you cannot use delete on the pointer; it must be
 /// deallocated using an explicit destructor call followed by
 /// \c Context.Deallocate(Ptr).
 ///
 /// \param Bytes The number of bytes to allocate. Calculated by the compiler.
 /// \param C The MCContext that provides the allocator.
 /// \param Alignment The alignment of the allocated memory (if the underlying
 ///                  allocator supports it).
 /// \return The allocated memory. Could be NULL.
 inline void *operator new(size_t Bytes, llvm::MCContext &C,
                           size_t Alignment = 8) throw() {
   return C.allocate(Bytes, Alignment);
 }
 /// \brief Placement delete companion to the new above.
 ///
 /// This operator is just a companion to the new above. There is no way of
 /// invoking it directly; see the new operator for more details. This operator
 /// is called implicitly by the compiler if a placement new expression using
 /// the MCContext throws in the object constructor.
 inline void operator delete(void *Ptr, llvm::MCContext &C, size_t)
               throw () {
   C.deallocate(Ptr);
 }

 /// This placement form of operator new[] uses the MCContext's allocator for
 /// obtaining memory. It is a non-throwing new[], which means that it returns
 /// null on error.
 /// Usage looks like this (assuming there's an MCContext 'Context' in scope):
 /// \code
 /// // Default alignment (8)
 /// char *data = new (Context) char[10];
 /// // Specific alignment
 /// char *data = new (Context, 4) char[10];
 /// \endcode
 /// Please note that you cannot use delete on the pointer; it must be
 /// deallocated using an explicit destructor call followed by
 /// \c Context.Deallocate(Ptr).
 ///
 /// \param Bytes The number of bytes to allocate. Calculated by the compiler.
 /// \param C The MCContext that provides the allocator.
 /// \param Alignment The alignment of the allocated memory (if the underlying
 ///                  allocator supports it).
 /// \return The allocated memory. Could be NULL.
 inline void *operator new[](size_t Bytes, llvm::MCContext& C,
                             size_t Alignment = 8) throw() {
   return C.allocate(Bytes, Alignment);
 }

 /// \brief Placement delete[] companion to the new[] above.
 ///
 /// This operator is just a companion to the new[] above. There is no way of
 /// invoking it directly; see the new[] operator for more details. This operator
 /// is called implicitly by the compiler if a placement new[] expression using
 /// the MCContext throws in the object constructor.
 inline void operator delete[](void *Ptr, llvm::MCContext &C) throw () {
   C.deallocate(Ptr);
 }

 #endif
	//===- MCContext.h - Machine Code Context ------------------------ C++ --===//
	//
	// The LLVM Compiler Infrastructure
	//
	// This file is distributed under the University of Illinois Open Source
	// License. See LICENSE.TXT for details.
	//
	//===----------------------------------------------------------------------===//

	#ifndef LLVM_MC_MCCONTEXT_H
	#define LLVM_MC_MCCONTEXT_H

	#include "llvm/ADT/DenseMap.h"
	#include "llvm/ADT/SetVector.h"
	#include "llvm/ADT/SmallString.h"
	#include "llvm/ADT/SmallVector.h"
	#include "llvm/ADT/StringMap.h"
	#include "llvm/ADT/Twine.h"
	#include "llvm/MC/MCDwarf.h"
	#include "llvm/MC/SectionKind.h"
	#include "llvm/Support/Allocator.h"
	#include "llvm/Support/Compiler.h"
	#include "llvm/Support/raw_ostream.h"
	#include <map>
	#include <tuple>
	#include <vector> // FIXME: Shouldn't be needed.

	namespace llvm {
	class MCAsmInfo;
	class MCExpr;
	class MCSection;
	class MCSymbol;
	class MCSymbolELF;
	class MCLabel;
	struct MCDwarfFile;
	class MCDwarfLoc;
	class MCObjectFileInfo;
	class MCRegisterInfo;
	class MCLineSection;
	class SMLoc;
	class MCSectionMachO;
	class MCSectionELF;
	class MCSectionCOFF;

	/// Context object for machine code objects. This class owns all of the
	/// sections that it creates.
	///
	class MCContext {
	MCContext(const MCContext &) = delete;
	MCContext &operator=(const MCContext &) = delete;

	public:
	typedef StringMap<MCSymbol *, BumpPtrAllocator &> SymbolTable;

	private:
	/// The SourceMgr for this object, if any.
	const SourceMgr *SrcMgr;

	/// The MCAsmInfo for this target.
	const MCAsmInfo *MAI;

	/// The MCRegisterInfo for this target.
	const MCRegisterInfo *MRI;

	/// The MCObjectFileInfo for this target.
	const MCObjectFileInfo *MOFI;

	/// Allocator object used for creating machine code objects.
	///
	/// We use a bump pointer allocator to avoid the need to track all allocated
	/// objects.
	BumpPtrAllocator Allocator;

	/// Bindings of names to symbols.
	SymbolTable Symbols;

	/// ELF sections can have a corresponding symbol. This maps one to the
	/// other.
	DenseMap<const MCSectionELF , MCSymbolELF > SectionSymbols;

	/// A mapping from a local label number and an instance count to a symbol.
	/// For example, in the assembly
	/// 1:
	/// 2:
	/// 1:
	/// We have three labels represented by the pairs (1, 0), (2, 0) and (1, 1)
	DenseMap<std::pair<unsigned, unsigned>, MCSymbol *> LocalSymbols;

	/// Keeps tracks of names that were used both for used declared and
	/// artificial symbols.
	StringMap<bool, BumpPtrAllocator &> UsedNames;

	/// The next ID to dole out to an unnamed assembler temporary symbol with
	/// a given prefix.
	StringMap<unsigned> NextID;

	/// Instances of directional local labels.
	DenseMap<unsigned, MCLabel *> Instances;
	/// NextInstance() creates the next instance of the directional local label
	/// for the LocalLabelVal and adds it to the map if needed.
	unsigned NextInstance(unsigned LocalLabelVal);
	/// GetInstance() gets the current instance of the directional local label
	/// for the LocalLabelVal and adds it to the map if needed.
	unsigned GetInstance(unsigned LocalLabelVal);

	/// The file name of the log file from the environment variable
	/// AS_SECURE_LOG_FILE. Which must be set before the .secure_log_unique
	/// directive is used or it is an error.
	char *SecureLogFile;
	/// The stream that gets written to for the .secure_log_unique directive.
	raw_ostream *SecureLog;
	/// Boolean toggled when .secure_log_unique / .secure_log_reset is seen to
	/// catch errors if .secure_log_unique appears twice without
	/// .secure_log_reset appearing between them.
	bool SecureLogUsed;

	/// The compilation directory to use for DW_AT_comp_dir.
	SmallString<128> CompilationDir;

	/// The main file name if passed in explicitly.
	std::string MainFileName;

	/// The dwarf file and directory tables from the dwarf .file directive.
	/// We now emit a line table for each compile unit. To reduce the prologue
	/// size of each line table, the files and directories used by each compile
	/// unit are separated.
	std::map<unsigned, MCDwarfLineTable> MCDwarfLineTablesCUMap;

	/// The current dwarf line information from the last dwarf .loc directive.
	MCDwarfLoc CurrentDwarfLoc;
	bool DwarfLocSeen;

	/// Generate dwarf debugging info for assembly source files.
	bool GenDwarfForAssembly;

	/// The current dwarf file number when generate dwarf debugging info for
	/// assembly source files.
	unsigned GenDwarfFileNumber;

	/// Sections for generating the .debug_ranges and .debug_aranges sections.
	SetVector<MCSection *> SectionsForRanges;

	/// The information gathered from labels that will have dwarf label
	/// entries when generating dwarf assembly source files.
	std::vector<MCGenDwarfLabelEntry> MCGenDwarfLabelEntries;

	/// The string to embed in the debug information for the compile unit, if
	/// non-empty.
	StringRef DwarfDebugFlags;

	/// The string to embed in as the dwarf AT_producer for the compile unit, if
	/// non-empty.
	StringRef DwarfDebugProducer;

	/// The maximum version of dwarf that we should emit.
	uint16_t DwarfVersion;

	/// Honor temporary labels, this is useful for debugging semantic
	/// differences between temporary and non-temporary labels (primarily on
	/// Darwin).
	bool AllowTemporaryLabels;
	bool UseNamesOnTempLabels = true;

	/// The Compile Unit ID that we are currently processing.
	unsigned DwarfCompileUnitID;

	struct ELFSectionKey {
	std::string SectionName;
	StringRef GroupName;
	unsigned UniqueID;
	ELFSectionKey(StringRef SectionName, StringRef GroupName,
	unsigned UniqueID)
	: SectionName(SectionName), GroupName(GroupName), UniqueID(UniqueID) {
	}
	bool operator<(const ELFSectionKey &Other) const {
	if (SectionName != Other.SectionName)
	return SectionName < Other.SectionName;
	if (GroupName != Other.GroupName)
	return GroupName < Other.GroupName;
	return UniqueID < Other.UniqueID;
	}
	};

	struct COFFSectionKey {
	std::string SectionName;
	StringRef GroupName;
	int SelectionKey;
	COFFSectionKey(StringRef SectionName, StringRef GroupName,
	int SelectionKey)
	: SectionName(SectionName), GroupName(GroupName),
	SelectionKey(SelectionKey) {}
	bool operator<(const COFFSectionKey &Other) const {
	if (SectionName != Other.SectionName)
	return SectionName < Other.SectionName;
	if (GroupName != Other.GroupName)
	return GroupName < Other.GroupName;
	return SelectionKey < Other.SelectionKey;
	}
	};

	StringMap<MCSectionMachO *> MachOUniquingMap;
	std::map<ELFSectionKey, MCSectionELF *> ELFUniquingMap;
	std::map<COFFSectionKey, MCSectionCOFF *> COFFUniquingMap;
	StringMap<bool> ELFRelSecNames;

	/// Do automatic reset in destructor
	bool AutoReset;

	MCSymbol createSymbolImpl(const StringMapEntry<bool> Name,
	bool CanBeUnnamed);
	MCSymbol *createSymbol(StringRef Name, bool AlwaysAddSuffix,
	bool IsTemporary);

	MCSymbol *getOrCreateDirectionalLocalSymbol(unsigned LocalLabelVal,
	unsigned Instance);

	public:
	explicit MCContext(const MCAsmInfo MAI, const MCRegisterInfo MRI,
	const MCObjectFileInfo *MOFI,
	const SourceMgr *Mgr = nullptr, bool DoAutoReset = true);
	~MCContext();

	const SourceMgr *getSourceManager() const { return SrcMgr; }

	const MCAsmInfo *getAsmInfo() const { return MAI; }

	const MCRegisterInfo *getRegisterInfo() const { return MRI; }

	const MCObjectFileInfo *getObjectFileInfo() const { return MOFI; }

	void setAllowTemporaryLabels(bool Value) { AllowTemporaryLabels = Value; }
	void setUseNamesOnTempLabels(bool Value) { UseNamesOnTempLabels = Value; }

	/// \name Module Lifetime Management
	/// @{

	/// reset - return object to right after construction state to prepare
	/// to process a new module
	void reset();

	/// @}

	/// \name Symbol Management
	/// @{

	/// Create and return a new linker temporary symbol with a unique but
	/// unspecified name.
	MCSymbol *createLinkerPrivateTempSymbol();

	/// Create and return a new assembler temporary symbol with a unique but
	/// unspecified name.
	MCSymbol *createTempSymbol(bool CanBeUnnamed = true);

	MCSymbol *createTempSymbol(const Twine &Name, bool AlwaysAddSuffix,
	bool CanBeUnnamed = true);

	/// Create the definition of a directional local symbol for numbered label
	/// (used for "1:" definitions).
	MCSymbol *createDirectionalLocalSymbol(unsigned LocalLabelVal);

	/// Create and return a directional local symbol for numbered label (used
	/// for "1b" or 1f" references).
	MCSymbol *getDirectionalLocalSymbol(unsigned LocalLabelVal, bool Before);

	/// Lookup the symbol inside with the specified \p Name. If it exists,
	/// return it. If not, create a forward reference and return it.
	///
	/// \param Name - The symbol name, which must be unique across all symbols.
	MCSymbol *getOrCreateSymbol(const Twine &Name);

	MCSymbolELF *getOrCreateSectionSymbol(const MCSectionELF &Section);

	/// Gets a symbol that will be defined to the final stack offset of a local
	/// variable after codegen.
	///
	/// \param Idx - The index of a local variable passed to @llvm.localescape.
	MCSymbol *getOrCreateFrameAllocSymbol(StringRef FuncName, unsigned Idx);

	MCSymbol *getOrCreateParentFrameOffsetSymbol(StringRef FuncName);

	MCSymbol *getOrCreateLSDASymbol(StringRef FuncName);

	/// Get the symbol for \p Name, or null.
	MCSymbol *lookupSymbol(const Twine &Name) const;

	/// getSymbols - Get a reference for the symbol table for clients that
	/// want to, for example, iterate over all symbols. 'const' because we
	/// still want any modifications to the table itself to use the MCContext
	/// APIs.
	const SymbolTable &getSymbols() const { return Symbols; }

	/// @}

	/// \name Section Management
	/// @{

	/// Return the MCSection for the specified mach-o section. This requires
	/// the operands to be valid.
	MCSectionMachO *getMachOSection(StringRef Segment, StringRef Section,
	unsigned TypeAndAttributes,
	unsigned Reserved2, SectionKind K,
	const char *BeginSymName = nullptr);

	MCSectionMachO *getMachOSection(StringRef Segment, StringRef Section,
	unsigned TypeAndAttributes, SectionKind K,
	const char *BeginSymName = nullptr) {
	return getMachOSection(Segment, Section, TypeAndAttributes, 0, K,
	BeginSymName);
	}

	MCSectionELF *getELFSection(StringRef Section, unsigned Type,
	unsigned Flags) {
	return getELFSection(Section, Type, Flags, nullptr);
	}

	MCSectionELF *getELFSection(StringRef Section, unsigned Type,
	unsigned Flags, const char *BeginSymName) {
	return getELFSection(Section, Type, Flags, 0, "", BeginSymName);
	}

	MCSectionELF *getELFSection(StringRef Section, unsigned Type,
	unsigned Flags, unsigned EntrySize,
	StringRef Group) {
	return getELFSection(Section, Type, Flags, EntrySize, Group, nullptr);
	}

	MCSectionELF *getELFSection(StringRef Section, unsigned Type,
	unsigned Flags, unsigned EntrySize,
	StringRef Group, const char *BeginSymName) {
	return getELFSection(Section, Type, Flags, EntrySize, Group, ~0,
	BeginSymName);
	}

	MCSectionELF *getELFSection(StringRef Section, unsigned Type,
	unsigned Flags, unsigned EntrySize,
	StringRef Group, unsigned UniqueID) {
	return getELFSection(Section, Type, Flags, EntrySize, Group, UniqueID,
	nullptr);
	}

	MCSectionELF *getELFSection(StringRef Section, unsigned Type,
	unsigned Flags, unsigned EntrySize,
	StringRef Group, unsigned UniqueID,
	const char *BeginSymName);

	MCSectionELF *getELFSection(StringRef Section, unsigned Type,
	unsigned Flags, unsigned EntrySize,
	const MCSymbolELF *Group, unsigned UniqueID,
	const char *BeginSymName,
	const MCSectionELF *Associated);

	MCSectionELF *createELFRelSection(StringRef Name, unsigned Type,
	unsigned Flags, unsigned EntrySize,
	const MCSymbolELF *Group,
	const MCSectionELF *Associated);

	void renameELFSection(MCSectionELF *Section, StringRef Name);

	MCSectionELF createELFGroupSection(const MCSymbolELF Group);

	MCSectionCOFF *getCOFFSection(StringRef Section, unsigned Characteristics,
	SectionKind Kind, StringRef COMDATSymName,
	int Selection,
	const char *BeginSymName = nullptr);

	MCSectionCOFF *getCOFFSection(StringRef Section, unsigned Characteristics,
	SectionKind Kind,
	const char *BeginSymName = nullptr);

	MCSectionCOFF *getCOFFSection(StringRef Section);

	/// Gets or creates a section equivalent to Sec that is associated with the
	/// section containing KeySym. For example, to create a debug info section
	/// associated with an inline function, pass the normal debug info section
	/// as Sec and the function symbol as KeySym.
	MCSectionCOFF getAssociativeCOFFSection(MCSectionCOFF Sec,
	const MCSymbol *KeySym);

	/// @}

	/// \name Dwarf Management
	/// @{

	/// \brief Get the compilation directory for DW_AT_comp_dir
	/// This can be overridden by clients which want to control the reported
	/// compilation directory and have it be something other than the current
	/// working directory.
	/// Returns an empty string if the current directory cannot be determined.
	StringRef getCompilationDir() const { return CompilationDir; }

	/// \brief Set the compilation directory for DW_AT_comp_dir
	/// Override the default (CWD) compilation directory.
	void setCompilationDir(StringRef S) { CompilationDir = S.str(); }

	/// \brief Get the main file name for use in error messages and debug
	/// info. This can be set to ensure we've got the correct file name
	/// after preprocessing or for -save-temps.
	const std::string &getMainFileName() const { return MainFileName; }

	/// \brief Set the main file name and override the default.
	void setMainFileName(StringRef S) { MainFileName = S; }

	/// Creates an entry in the dwarf file and directory tables.
	unsigned getDwarfFile(StringRef Directory, StringRef FileName,
	unsigned FileNumber, unsigned CUID);

	bool isValidDwarfFileNumber(unsigned FileNumber, unsigned CUID = 0);

	const std::map<unsigned, MCDwarfLineTable> &getMCDwarfLineTables() const {
	return MCDwarfLineTablesCUMap;
	}

	MCDwarfLineTable &getMCDwarfLineTable(unsigned CUID) {
	return MCDwarfLineTablesCUMap[CUID];
	}

	const MCDwarfLineTable &getMCDwarfLineTable(unsigned CUID) const {
	auto I = MCDwarfLineTablesCUMap.find(CUID);
	assert(I != MCDwarfLineTablesCUMap.end());
	return I->second;
	}

	const SmallVectorImpl<MCDwarfFile> &getMCDwarfFiles(unsigned CUID = 0) {
	return getMCDwarfLineTable(CUID).getMCDwarfFiles();
	}
	const SmallVectorImpl<std::string> &getMCDwarfDirs(unsigned CUID = 0) {
	return getMCDwarfLineTable(CUID).getMCDwarfDirs();
	}

	bool hasMCLineSections() const {
	for (const auto &Table : MCDwarfLineTablesCUMap)
	if (!Table.second.getMCDwarfFiles().empty() \|\| Table.second.getLabel())
	return true;
	return false;
	}
	unsigned getDwarfCompileUnitID() { return DwarfCompileUnitID; }
	void setDwarfCompileUnitID(unsigned CUIndex) {
	DwarfCompileUnitID = CUIndex;
	}
	void setMCLineTableCompilationDir(unsigned CUID, StringRef CompilationDir) {
	getMCDwarfLineTable(CUID).setCompilationDir(CompilationDir);
	}

	/// Saves the information from the currently parsed dwarf .loc directive
	/// and sets DwarfLocSeen. When the next instruction is assembled an entry
	/// in the line number table with this information and the address of the
	/// instruction will be created.
	void setCurrentDwarfLoc(unsigned FileNum, unsigned Line, unsigned Column,
	unsigned Flags, unsigned Isa,
	unsigned Discriminator) {
	CurrentDwarfLoc.setFileNum(FileNum);
	CurrentDwarfLoc.setLine(Line);
	CurrentDwarfLoc.setColumn(Column);
	CurrentDwarfLoc.setFlags(Flags);
	CurrentDwarfLoc.setIsa(Isa);
	CurrentDwarfLoc.setDiscriminator(Discriminator);
	DwarfLocSeen = true;
	}
	void clearDwarfLocSeen() { DwarfLocSeen = false; }

	bool getDwarfLocSeen() { return DwarfLocSeen; }
	const MCDwarfLoc &getCurrentDwarfLoc() { return CurrentDwarfLoc; }

	bool getGenDwarfForAssembly() { return GenDwarfForAssembly; }
	void setGenDwarfForAssembly(bool Value) { GenDwarfForAssembly = Value; }
	unsigned getGenDwarfFileNumber() { return GenDwarfFileNumber; }
	void setGenDwarfFileNumber(unsigned FileNumber) {
	GenDwarfFileNumber = FileNumber;
	}
	const SetVector<MCSection *> &getGenDwarfSectionSyms() {
	return SectionsForRanges;
	}
	bool addGenDwarfSection(MCSection *Sec) {
	return SectionsForRanges.insert(Sec);
	}

	void finalizeDwarfSections(MCStreamer &MCOS);
	const std::vector<MCGenDwarfLabelEntry> &getMCGenDwarfLabelEntries() const {
	return MCGenDwarfLabelEntries;
	}
	void addMCGenDwarfLabelEntry(const MCGenDwarfLabelEntry &E) {
	MCGenDwarfLabelEntries.push_back(E);
	}

	void setDwarfDebugFlags(StringRef S) { DwarfDebugFlags = S; }
	StringRef getDwarfDebugFlags() { return DwarfDebugFlags; }

	void setDwarfDebugProducer(StringRef S) { DwarfDebugProducer = S; }
	StringRef getDwarfDebugProducer() { return DwarfDebugProducer; }

	void setDwarfVersion(uint16_t v) { DwarfVersion = v; }
	uint16_t getDwarfVersion() const { return DwarfVersion; }

	/// @}

	char *getSecureLogFile() { return SecureLogFile; }
	raw_ostream *getSecureLog() { return SecureLog; }
	bool getSecureLogUsed() { return SecureLogUsed; }
	void setSecureLog(raw_ostream *Value) { SecureLog = Value; }
	void setSecureLogUsed(bool Value) { SecureLogUsed = Value; }

	void *allocate(unsigned Size, unsigned Align = 8) {
	return Allocator.Allocate(Size, Align);
	}
	void deallocate(void *Ptr) {}

	// Unrecoverable error has occurred. Display the best diagnostic we can
	// and bail via exit(1). For now, most MC backend errors are unrecoverable.
	// FIXME: We should really do something about that.
	LLVM_ATTRIBUTE_NORETURN void reportFatalError(SMLoc L,
	const Twine &Msg) const;
	};

	} // end namespace llvm

	// operator new and delete aren't allowed inside namespaces.
	// The throw specifications are mandated by the standard.
	/// \brief Placement new for using the MCContext's allocator.
	///
	/// This placement form of operator new uses the MCContext's allocator for
	/// obtaining memory. It is a non-throwing new, which means that it returns
	/// null on error. (If that is what the allocator does. The current does, so if
	/// this ever changes, this operator will have to be changed, too.)
	/// Usage looks like this (assuming there's an MCContext 'Context' in scope):
	/// \code
	/// // Default alignment (8)
	/// IntegerLiteral *Ex = new (Context) IntegerLiteral(arguments);
	/// // Specific alignment
	/// IntegerLiteral *Ex2 = new (Context, 4) IntegerLiteral(arguments);
	/// \endcode
	/// Please note that you cannot use delete on the pointer; it must be
	/// deallocated using an explicit destructor call followed by
	/// \c Context.Deallocate(Ptr).
	///
	/// \param Bytes The number of bytes to allocate. Calculated by the compiler.
	/// \param C The MCContext that provides the allocator.
	/// \param Alignment The alignment of the allocated memory (if the underlying
	/// allocator supports it).
	/// \return The allocated memory. Could be NULL.
	inline void *operator new(size_t Bytes, llvm::MCContext &C,
	size_t Alignment = 8) throw() {
	return C.allocate(Bytes, Alignment);
	}
	/// \brief Placement delete companion to the new above.
	///
	/// This operator is just a companion to the new above. There is no way of
	/// invoking it directly; see the new operator for more details. This operator
	/// is called implicitly by the compiler if a placement new expression using
	/// the MCContext throws in the object constructor.
	inline void operator delete(void *Ptr, llvm::MCContext &C, size_t)
	throw () {
	C.deallocate(Ptr);
	}

	/// This placement form of operator new[] uses the MCContext's allocator for
	/// obtaining memory. It is a non-throwing new[], which means that it returns
	/// null on error.
	/// Usage looks like this (assuming there's an MCContext 'Context' in scope):
	/// \code
	/// // Default alignment (8)
	/// char *data = new (Context) char[10];
	/// // Specific alignment
	/// char *data = new (Context, 4) char[10];
	/// \endcode
	/// Please note that you cannot use delete on the pointer; it must be
	/// deallocated using an explicit destructor call followed by
	/// \c Context.Deallocate(Ptr).
	///
	/// \param Bytes The number of bytes to allocate. Calculated by the compiler.
	/// \param C The MCContext that provides the allocator.
	/// \param Alignment The alignment of the allocated memory (if the underlying
	/// allocator supports it).
	/// \return The allocated memory. Could be NULL.
	inline void *operator new[](size_t Bytes, llvm::MCContext& C,
	size_t Alignment = 8) throw() {
	return C.allocate(Bytes, Alignment);
	}

	/// \brief Placement delete[] companion to the new[] above.
	///
	/// This operator is just a companion to the new[] above. There is no way of
	/// invoking it directly; see the new[] operator for more details. This operator
	/// is called implicitly by the compiler if a placement new[] expression using
	/// the MCContext throws in the object constructor.
	inline void operator delete[](void *Ptr, llvm::MCContext &C) throw () {
	C.deallocate(Ptr);
	}

	#endif