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/SmallVector.h"
 #include "llvm/ADT/StringMap.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 <vector> // FIXME: Shouldn't be needed.

 namespace llvm {
   class MCAsmInfo;
   class MCExpr;
   class MCSection;
   class MCSymbol;
   class MCLabel;
   class MCDwarfFile;
   class MCDwarfLoc;
   class MCObjectFileInfo;
   class MCRegisterInfo;
   class MCLineSection;
   class SMLoc;
   class StringRef;
   class Twine;
   class MCSectionMachO;
   class MCSectionELF;

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

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

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

     /// NextUniqueID - The next ID to dole out to an unnamed assembler temporary
     /// symbol.
     unsigned NextUniqueID;

     /// 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(int64_t LocalLabelVal);
     /// GetInstance() gets the current instance of the directional local label
     /// for the LocalLabelVal and adds it to the map if needed.
     unsigned GetInstance(int64_t 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.
     std::string 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.
     typedef std::map<unsigned, SmallVector<MCDwarfFile *, 4> > MCDwarfFilesMap;
     MCDwarfFilesMap MCDwarfFilesCUMap;
     std::map<unsigned, SmallVector<StringRef, 4> > MCDwarfDirsCUMap;

     /// 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;

     /// The default initial text section that we generate dwarf debugging line
     /// info for when generating dwarf assembly source files.
     const MCSection *GenDwarfSection;
     /// Symbols created for the start and end of this section.
     MCSymbol *GenDwarfSectionStartSym, *GenDwarfSectionEndSym;

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

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

     /// The dwarf line information from the .loc directives for the sections
     /// with assembled machine instructions have after seeing .loc directives.
     DenseMap<const MCSection *, MCLineSection *> MCLineSections;
     /// We need a deterministic iteration order, so we remember the order
     /// the elements were added.
     std::vector<const MCSection *> MCLineSectionOrder;
     /// The Compile Unit ID that we are currently processing.
     unsigned DwarfCompileUnitID;
     /// The line table start symbol for each Compile Unit.
     DenseMap<unsigned, MCSymbol *> MCLineTableSymbols;

     void *MachOUniquingMap, *ELFUniquingMap, *COFFUniquingMap;

     /// Do automatic reset in destructor
     bool AutoReset;

     MCSymbol *CreateSymbol(StringRef Name);

   public:
     explicit MCContext(const MCAsmInfo &MAI, const MCRegisterInfo &MRI,
                        const MCObjectFileInfo *MOFI, const SourceMgr *Mgr = 0,
                        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; }

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

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

     /// @}

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

     /// CreateTempSymbol - Create and return a new assembler temporary symbol
     /// with a unique but unspecified name.
     MCSymbol *CreateTempSymbol();

     /// getUniqueSymbolID() - Return a unique identifier for use in constructing
     /// symbol names.
     unsigned getUniqueSymbolID() { return NextUniqueID++; }

     /// CreateDirectionalLocalSymbol - Create the definition of a directional
     /// local symbol for numbered label (used for "1:" definitions).
     MCSymbol *CreateDirectionalLocalSymbol(int64_t LocalLabelVal);

     /// GetDirectionalLocalSymbol - Create and return a directional local
     /// symbol for numbered label (used for "1b" or 1f" references).
     MCSymbol *GetDirectionalLocalSymbol(int64_t LocalLabelVal, int bORf);

     /// GetOrCreateSymbol - 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(StringRef Name);
     MCSymbol *GetOrCreateSymbol(const Twine &Name);

     /// LookupSymbol - Get the symbol for \p Name, or null.
     MCSymbol *LookupSymbol(StringRef Name) const;
     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
     /// @{

     /// getMachOSection - Return the MCSection for the specified mach-o section.
     /// This requires the operands to be valid.
     const MCSectionMachO *getMachOSection(StringRef Segment,
                                           StringRef Section,
                                           unsigned TypeAndAttributes,
                                           unsigned Reserved2,
                                           SectionKind K);
     const MCSectionMachO *getMachOSection(StringRef Segment,
                                           StringRef Section,
                                           unsigned TypeAndAttributes,
                                           SectionKind K) {
       return getMachOSection(Segment, Section, TypeAndAttributes, 0, K);
     }

     const MCSectionELF *getELFSection(StringRef Section, unsigned Type,
                                       unsigned Flags, SectionKind Kind);

     const MCSectionELF *getELFSection(StringRef Section, unsigned Type,
                                       unsigned Flags, SectionKind Kind,
                                       unsigned EntrySize, StringRef Group);

     const MCSectionELF *CreateELFGroupSection();

     const MCSection *getCOFFSection(StringRef Section, unsigned Characteristics,
                                     int Selection, SectionKind Kind);

     const MCSection *getCOFFSection(StringRef Section, unsigned Characteristics,
                                     SectionKind Kind) {
       return getCOFFSection (Section, Characteristics, 0, Kind);
     }


     /// @}

     /// @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.
     const std::string &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.str(); }

     /// GetDwarfFile - 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);

     bool hasDwarfFiles() const {
       // Traverse MCDwarfFilesCUMap and check whether each entry is empty.
       MCDwarfFilesMap::const_iterator MapB, MapE;
       for (MapB = MCDwarfFilesCUMap.begin(), MapE = MCDwarfFilesCUMap.end();
            MapB != MapE; MapB++)
         if (!MapB->second.empty())
            return true;
       return false;
     }

     const SmallVectorImpl<MCDwarfFile *> &getMCDwarfFiles(unsigned CUID = 0) {
       return MCDwarfFilesCUMap[CUID];
     }
     const SmallVectorImpl<StringRef> &getMCDwarfDirs(unsigned CUID = 0) {
       return MCDwarfDirsCUMap[CUID];
     }

     const DenseMap<const MCSection *, MCLineSection *>
     &getMCLineSections() const {
       return MCLineSections;
     }
     const std::vector<const MCSection *> &getMCLineSectionOrder() const {
       return MCLineSectionOrder;
     }
     void addMCLineSection(const MCSection *Sec, MCLineSection *Line) {
       MCLineSections[Sec] = Line;
       MCLineSectionOrder.push_back(Sec);
     }
     unsigned getDwarfCompileUnitID() {
       return DwarfCompileUnitID;
     }
     void setDwarfCompileUnitID(unsigned CUIndex) {
       DwarfCompileUnitID = CUIndex;
     }
     const DenseMap<unsigned, MCSymbol *> &getMCLineTableSymbols() const {
       return MCLineTableSymbols;
     }
     MCSymbol *getMCLineTableSymbol(unsigned ID) const {
       DenseMap<unsigned, MCSymbol *>::const_iterator CIter =
         MCLineTableSymbols.find(ID);
       if (CIter == MCLineTableSymbols.end())
         return NULL;
       return CIter->second;
     }
     void setMCLineTableSymbol(MCSymbol *Sym, unsigned ID) {
       MCLineTableSymbols[ID] = Sym;
     }

     /// setCurrentDwarfLoc - 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; }
     unsigned nextGenDwarfFileNumber() { return ++GenDwarfFileNumber; }
     const MCSection *getGenDwarfSection() { return GenDwarfSection; }
     void setGenDwarfSection(const MCSection *Sec) { GenDwarfSection = Sec; }
     MCSymbol *getGenDwarfSectionStartSym() { return GenDwarfSectionStartSym; }
     void setGenDwarfSectionStartSym(MCSymbol *Sym) {
       GenDwarfSectionStartSym = Sym;
     }
     MCSymbol *getGenDwarfSectionEndSym() { return GenDwarfSectionEndSym; }
     void setGenDwarfSectionEndSym(MCSymbol *Sym) {
       GenDwarfSectionEndSym = Sym;
     }
     const std::vector<const 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; }

     /// @}

     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 occured. 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 FatalError(SMLoc L, const Twine &Msg);
   };

 } // 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 (16)
 /// IntegerLiteral *Ex = new (Context) IntegerLiteral(arguments);
 /// // Specific alignment
 /// IntegerLiteral *Ex2 = new (Context, 8) 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 = 16) 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 (16)
 /// char *data = new (Context) char[10];
 /// // Specific alignment
 /// char *data = new (Context, 8) 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 = 16) 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/SmallVector.h"
	#include "llvm/ADT/StringMap.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 <vector> // FIXME: Shouldn't be needed.

	namespace llvm {
	class MCAsmInfo;
	class MCExpr;
	class MCSection;
	class MCSymbol;
	class MCLabel;
	class MCDwarfFile;
	class MCDwarfLoc;
	class MCObjectFileInfo;
	class MCRegisterInfo;
	class MCLineSection;
	class SMLoc;
	class StringRef;
	class Twine;
	class MCSectionMachO;
	class MCSectionELF;

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

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

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

	/// NextUniqueID - The next ID to dole out to an unnamed assembler temporary
	/// symbol.
	unsigned NextUniqueID;

	/// 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(int64_t LocalLabelVal);
	/// GetInstance() gets the current instance of the directional local label
	/// for the LocalLabelVal and adds it to the map if needed.
	unsigned GetInstance(int64_t 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.
	std::string 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.
	typedef std::map<unsigned, SmallVector<MCDwarfFile *, 4> > MCDwarfFilesMap;
	MCDwarfFilesMap MCDwarfFilesCUMap;
	std::map<unsigned, SmallVector<StringRef, 4> > MCDwarfDirsCUMap;

	/// 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;

	/// The default initial text section that we generate dwarf debugging line
	/// info for when generating dwarf assembly source files.
	const MCSection *GenDwarfSection;
	/// Symbols created for the start and end of this section.
	MCSymbol GenDwarfSectionStartSym, GenDwarfSectionEndSym;

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

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

	/// The dwarf line information from the .loc directives for the sections
	/// with assembled machine instructions have after seeing .loc directives.
	DenseMap<const MCSection , MCLineSection > MCLineSections;
	/// We need a deterministic iteration order, so we remember the order
	/// the elements were added.
	std::vector<const MCSection *> MCLineSectionOrder;
	/// The Compile Unit ID that we are currently processing.
	unsigned DwarfCompileUnitID;
	/// The line table start symbol for each Compile Unit.
	DenseMap<unsigned, MCSymbol *> MCLineTableSymbols;

	void MachOUniquingMap, ELFUniquingMap, *COFFUniquingMap;

	/// Do automatic reset in destructor
	bool AutoReset;

	MCSymbol *CreateSymbol(StringRef Name);

	public:
	explicit MCContext(const MCAsmInfo &MAI, const MCRegisterInfo &MRI,
	const MCObjectFileInfo MOFI, const SourceMgr Mgr = 0,
	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; }

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

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

	/// @}

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

	/// CreateTempSymbol - Create and return a new assembler temporary symbol
	/// with a unique but unspecified name.
	MCSymbol *CreateTempSymbol();

	/// getUniqueSymbolID() - Return a unique identifier for use in constructing
	/// symbol names.
	unsigned getUniqueSymbolID() { return NextUniqueID++; }

	/// CreateDirectionalLocalSymbol - Create the definition of a directional
	/// local symbol for numbered label (used for "1:" definitions).
	MCSymbol *CreateDirectionalLocalSymbol(int64_t LocalLabelVal);

	/// GetDirectionalLocalSymbol - Create and return a directional local
	/// symbol for numbered label (used for "1b" or 1f" references).
	MCSymbol *GetDirectionalLocalSymbol(int64_t LocalLabelVal, int bORf);

	/// GetOrCreateSymbol - 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(StringRef Name);
	MCSymbol *GetOrCreateSymbol(const Twine &Name);

	/// LookupSymbol - Get the symbol for \p Name, or null.
	MCSymbol *LookupSymbol(StringRef Name) const;
	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
	/// @{

	/// getMachOSection - Return the MCSection for the specified mach-o section.
	/// This requires the operands to be valid.
	const MCSectionMachO *getMachOSection(StringRef Segment,
	StringRef Section,
	unsigned TypeAndAttributes,
	unsigned Reserved2,
	SectionKind K);
	const MCSectionMachO *getMachOSection(StringRef Segment,
	StringRef Section,
	unsigned TypeAndAttributes,
	SectionKind K) {
	return getMachOSection(Segment, Section, TypeAndAttributes, 0, K);
	}

	const MCSectionELF *getELFSection(StringRef Section, unsigned Type,
	unsigned Flags, SectionKind Kind);

	const MCSectionELF *getELFSection(StringRef Section, unsigned Type,
	unsigned Flags, SectionKind Kind,
	unsigned EntrySize, StringRef Group);

	const MCSectionELF *CreateELFGroupSection();

	const MCSection *getCOFFSection(StringRef Section, unsigned Characteristics,
	int Selection, SectionKind Kind);

	const MCSection *getCOFFSection(StringRef Section, unsigned Characteristics,
	SectionKind Kind) {
	return getCOFFSection (Section, Characteristics, 0, Kind);
	}


	/// @}

	/// @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.
	const std::string &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.str(); }

	/// GetDwarfFile - 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);

	bool hasDwarfFiles() const {
	// Traverse MCDwarfFilesCUMap and check whether each entry is empty.
	MCDwarfFilesMap::const_iterator MapB, MapE;
	for (MapB = MCDwarfFilesCUMap.begin(), MapE = MCDwarfFilesCUMap.end();
	MapB != MapE; MapB++)
	if (!MapB->second.empty())
	return true;
	return false;
	}

	const SmallVectorImpl<MCDwarfFile *> &getMCDwarfFiles(unsigned CUID = 0) {
	return MCDwarfFilesCUMap[CUID];
	}
	const SmallVectorImpl<StringRef> &getMCDwarfDirs(unsigned CUID = 0) {
	return MCDwarfDirsCUMap[CUID];
	}

	const DenseMap<const MCSection , MCLineSection >
	&getMCLineSections() const {
	return MCLineSections;
	}
	const std::vector<const MCSection *> &getMCLineSectionOrder() const {
	return MCLineSectionOrder;
	}
	void addMCLineSection(const MCSection Sec, MCLineSection Line) {
	MCLineSections[Sec] = Line;
	MCLineSectionOrder.push_back(Sec);
	}
	unsigned getDwarfCompileUnitID() {
	return DwarfCompileUnitID;
	}
	void setDwarfCompileUnitID(unsigned CUIndex) {
	DwarfCompileUnitID = CUIndex;
	}
	const DenseMap<unsigned, MCSymbol *> &getMCLineTableSymbols() const {
	return MCLineTableSymbols;
	}
	MCSymbol *getMCLineTableSymbol(unsigned ID) const {
	DenseMap<unsigned, MCSymbol *>::const_iterator CIter =
	MCLineTableSymbols.find(ID);
	if (CIter == MCLineTableSymbols.end())
	return NULL;
	return CIter->second;
	}
	void setMCLineTableSymbol(MCSymbol *Sym, unsigned ID) {
	MCLineTableSymbols[ID] = Sym;
	}

	/// setCurrentDwarfLoc - 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; }
	unsigned nextGenDwarfFileNumber() { return ++GenDwarfFileNumber; }
	const MCSection *getGenDwarfSection() { return GenDwarfSection; }
	void setGenDwarfSection(const MCSection *Sec) { GenDwarfSection = Sec; }
	MCSymbol *getGenDwarfSectionStartSym() { return GenDwarfSectionStartSym; }
	void setGenDwarfSectionStartSym(MCSymbol *Sym) {
	GenDwarfSectionStartSym = Sym;
	}
	MCSymbol *getGenDwarfSectionEndSym() { return GenDwarfSectionEndSym; }
	void setGenDwarfSectionEndSym(MCSymbol *Sym) {
	GenDwarfSectionEndSym = Sym;
	}
	const std::vector<const 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; }

	/// @}

	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 occured. 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 FatalError(SMLoc L, const Twine &Msg);
	};

	} // 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 (16)
	/// IntegerLiteral *Ex = new (Context) IntegerLiteral(arguments);
	/// // Specific alignment
	/// IntegerLiteral *Ex2 = new (Context, 8) 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 = 16) 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 (16)
	/// char *data = new (Context) char[10];
	/// // Specific alignment
	/// char *data = new (Context, 8) 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 = 16) 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