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      1 //===- MCStreamer.h - High-level Streaming Machine Code Output --*- C++ -*-===//
      2 //
      3 //                     The LLVM Compiler Infrastructure
      4 //
      5 // This file is distributed under the University of Illinois Open Source
      6 // License. See LICENSE.TXT for details.
      7 //
      8 //===----------------------------------------------------------------------===//
      9 //
     10 // This file declares the MCStreamer class.
     11 //
     12 //===----------------------------------------------------------------------===//
     13 
     14 #ifndef LLVM_MC_MCSTREAMER_H
     15 #define LLVM_MC_MCSTREAMER_H
     16 
     17 #include "llvm/ADT/ArrayRef.h"
     18 #include "llvm/ADT/SmallVector.h"
     19 #include "llvm/MC/MCAssembler.h"
     20 #include "llvm/MC/MCDirectives.h"
     21 #include "llvm/MC/MCDwarf.h"
     22 #include "llvm/MC/MCWin64EH.h"
     23 #include "llvm/Support/DataTypes.h"
     24 #include <string>
     25 
     26 namespace llvm {
     27   class MCAsmBackend;
     28   class MCCodeEmitter;
     29   class MCContext;
     30   class MCExpr;
     31   class MCInst;
     32   class MCInstPrinter;
     33   class MCSection;
     34   class MCSymbol;
     35   class StringRef;
     36   class Twine;
     37   class raw_ostream;
     38   class formatted_raw_ostream;
     39 
     40   typedef std::pair<const MCSection *, const MCExpr *> MCSectionSubPair;
     41 
     42   /// MCStreamer - Streaming machine code generation interface.  This interface
     43   /// is intended to provide a programatic interface that is very similar to the
     44   /// level that an assembler .s file provides.  It has callbacks to emit bytes,
     45   /// handle directives, etc.  The implementation of this interface retains
     46   /// state to know what the current section is etc.
     47   ///
     48   /// There are multiple implementations of this interface: one for writing out
     49   /// a .s file, and implementations that write out .o files of various formats.
     50   ///
     51   class MCStreamer {
     52   public:
     53     enum StreamerKind {
     54       SK_AsmStreamer,
     55       SK_NullStreamer,
     56       SK_RecordStreamer,
     57 
     58       // MCObjectStreamer subclasses.
     59       SK_ELFStreamer,
     60       SK_ARMELFStreamer,
     61       SK_MachOStreamer,
     62       SK_PureStreamer,
     63       SK_MipsELFStreamer,
     64       SK_WinCOFFStreamer
     65     };
     66 
     67   private:
     68     const StreamerKind Kind;
     69     MCContext &Context;
     70 
     71     MCStreamer(const MCStreamer&) LLVM_DELETED_FUNCTION;
     72     MCStreamer &operator=(const MCStreamer&) LLVM_DELETED_FUNCTION;
     73 
     74     bool EmitEHFrame;
     75     bool EmitDebugFrame;
     76 
     77     std::vector<MCDwarfFrameInfo> FrameInfos;
     78     MCDwarfFrameInfo *getCurrentFrameInfo();
     79     MCSymbol *EmitCFICommon();
     80     void EnsureValidFrame();
     81 
     82     std::vector<MCWin64EHUnwindInfo *> W64UnwindInfos;
     83     MCWin64EHUnwindInfo *CurrentW64UnwindInfo;
     84     void setCurrentW64UnwindInfo(MCWin64EHUnwindInfo *Frame);
     85     void EnsureValidW64UnwindInfo();
     86 
     87     MCSymbol* LastSymbol;
     88 
     89     /// SectionStack - This is stack of current and previous section
     90     /// values saved by PushSection.
     91     SmallVector<std::pair<MCSectionSubPair, MCSectionSubPair>, 4> SectionStack;
     92 
     93     bool AutoInitSections;
     94 
     95   protected:
     96     MCStreamer(StreamerKind Kind, MCContext &Ctx);
     97 
     98     const MCExpr *BuildSymbolDiff(MCContext &Context, const MCSymbol *A,
     99                                   const MCSymbol *B);
    100 
    101     const MCExpr *ForceExpAbs(const MCExpr* Expr);
    102 
    103     void RecordProcStart(MCDwarfFrameInfo &Frame);
    104     virtual void EmitCFIStartProcImpl(MCDwarfFrameInfo &Frame);
    105     void RecordProcEnd(MCDwarfFrameInfo &Frame);
    106     virtual void EmitCFIEndProcImpl(MCDwarfFrameInfo &CurFrame);
    107     void EmitFrames(bool usingCFI);
    108 
    109     MCWin64EHUnwindInfo *getCurrentW64UnwindInfo(){return CurrentW64UnwindInfo;}
    110     void EmitW64Tables();
    111 
    112   public:
    113     virtual ~MCStreamer();
    114 
    115     StreamerKind getKind() const { return Kind; }
    116 
    117     /// State management
    118     ///
    119     virtual void reset();
    120 
    121     MCContext &getContext() const { return Context; }
    122 
    123     unsigned getNumFrameInfos() {
    124       return FrameInfos.size();
    125     }
    126 
    127     const MCDwarfFrameInfo &getFrameInfo(unsigned i) {
    128       return FrameInfos[i];
    129     }
    130 
    131     ArrayRef<MCDwarfFrameInfo> getFrameInfos() {
    132       return FrameInfos;
    133     }
    134 
    135     unsigned getNumW64UnwindInfos() {
    136       return W64UnwindInfos.size();
    137     }
    138 
    139     MCWin64EHUnwindInfo &getW64UnwindInfo(unsigned i) {
    140       return *W64UnwindInfos[i];
    141     }
    142 
    143     /// @name Assembly File Formatting.
    144     /// @{
    145 
    146     /// isVerboseAsm - Return true if this streamer supports verbose assembly
    147     /// and if it is enabled.
    148     virtual bool isVerboseAsm() const { return false; }
    149 
    150     /// hasRawTextSupport - Return true if this asm streamer supports emitting
    151     /// unformatted text to the .s file with EmitRawText.
    152     virtual bool hasRawTextSupport() const { return false; }
    153 
    154     /// AddComment - Add a comment that can be emitted to the generated .s
    155     /// file if applicable as a QoI issue to make the output of the compiler
    156     /// more readable.  This only affects the MCAsmStreamer, and only when
    157     /// verbose assembly output is enabled.
    158     ///
    159     /// If the comment includes embedded \n's, they will each get the comment
    160     /// prefix as appropriate.  The added comment should not end with a \n.
    161     virtual void AddComment(const Twine &T) {}
    162 
    163     /// GetCommentOS - Return a raw_ostream that comments can be written to.
    164     /// Unlike AddComment, you are required to terminate comments with \n if you
    165     /// use this method.
    166     virtual raw_ostream &GetCommentOS();
    167 
    168     /// AddBlankLine - Emit a blank line to a .s file to pretty it up.
    169     virtual void AddBlankLine() {}
    170 
    171     /// @}
    172 
    173     /// @name Symbol & Section Management
    174     /// @{
    175 
    176     /// getCurrentSection - Return the current section that the streamer is
    177     /// emitting code to.
    178     MCSectionSubPair getCurrentSection() const {
    179       if (!SectionStack.empty())
    180         return SectionStack.back().first;
    181       return MCSectionSubPair();
    182     }
    183 
    184     /// getPreviousSection - Return the previous section that the streamer is
    185     /// emitting code to.
    186     MCSectionSubPair getPreviousSection() const {
    187       if (!SectionStack.empty())
    188         return SectionStack.back().second;
    189       return MCSectionSubPair();
    190     }
    191 
    192     /// ChangeSection - Update streamer for a new active section.
    193     ///
    194     /// This is called by PopSection and SwitchSection, if the current
    195     /// section changes.
    196     virtual void ChangeSection(const MCSection *, const MCExpr *) = 0;
    197 
    198     /// pushSection - Save the current and previous section on the
    199     /// section stack.
    200     void PushSection() {
    201       SectionStack.push_back(std::make_pair(getCurrentSection(),
    202                                             getPreviousSection()));
    203     }
    204 
    205     /// popSection - Restore the current and previous section from
    206     /// the section stack.  Calls ChangeSection as needed.
    207     ///
    208     /// Returns false if the stack was empty.
    209     bool PopSection() {
    210       if (SectionStack.size() <= 1)
    211         return false;
    212       MCSectionSubPair oldSection = SectionStack.pop_back_val().first;
    213       MCSectionSubPair curSection = SectionStack.back().first;
    214 
    215       if (oldSection != curSection)
    216         ChangeSection(curSection.first, curSection.second);
    217       return true;
    218     }
    219 
    220     bool SubSection(const MCExpr *Subsection) {
    221       if (SectionStack.empty())
    222         return false;
    223 
    224       SwitchSection(SectionStack.back().first.first, Subsection);
    225       return true;
    226     }
    227 
    228     /// SwitchSection - Set the current section where code is being emitted to
    229     /// @p Section.  This is required to update CurSection.
    230     ///
    231     /// This corresponds to assembler directives like .section, .text, etc.
    232     void SwitchSection(const MCSection *Section, const MCExpr *Subsection = 0) {
    233       assert(Section && "Cannot switch to a null section!");
    234       MCSectionSubPair curSection = SectionStack.back().first;
    235       SectionStack.back().second = curSection;
    236       if (MCSectionSubPair(Section, Subsection) != curSection) {
    237         SectionStack.back().first = MCSectionSubPair(Section, Subsection);
    238         ChangeSection(Section, Subsection);
    239       }
    240     }
    241 
    242     /// SwitchSectionNoChange - Set the current section where code is being
    243     /// emitted to @p Section.  This is required to update CurSection. This
    244     /// version does not call ChangeSection.
    245     void SwitchSectionNoChange(const MCSection *Section,
    246                                const MCExpr *Subsection = 0) {
    247       assert(Section && "Cannot switch to a null section!");
    248       MCSectionSubPair curSection = SectionStack.back().first;
    249       SectionStack.back().second = curSection;
    250       if (MCSectionSubPair(Section, Subsection) != curSection)
    251         SectionStack.back().first = MCSectionSubPair(Section, Subsection);
    252     }
    253 
    254     /// Initialize the streamer.
    255     void InitStreamer() {
    256       if (AutoInitSections)
    257         InitSections();
    258     }
    259 
    260     /// Tell this MCStreamer to call InitSections upon initialization.
    261     void setAutoInitSections(bool AutoInitSections) {
    262       this->AutoInitSections = AutoInitSections;
    263     }
    264 
    265     /// InitSections - Create the default sections and set the initial one.
    266     virtual void InitSections() = 0;
    267 
    268     /// InitToTextSection - Create a text section and switch the streamer to it.
    269     virtual void InitToTextSection() = 0;
    270 
    271     /// EmitLabel - Emit a label for @p Symbol into the current section.
    272     ///
    273     /// This corresponds to an assembler statement such as:
    274     ///   foo:
    275     ///
    276     /// @param Symbol - The symbol to emit. A given symbol should only be
    277     /// emitted as a label once, and symbols emitted as a label should never be
    278     /// used in an assignment.
    279     virtual void EmitLabel(MCSymbol *Symbol);
    280 
    281     virtual void EmitDebugLabel(MCSymbol *Symbol);
    282 
    283     virtual void EmitEHSymAttributes(const MCSymbol *Symbol,
    284                                      MCSymbol *EHSymbol);
    285 
    286     /// EmitAssemblerFlag - Note in the output the specified @p Flag.
    287     virtual void EmitAssemblerFlag(MCAssemblerFlag Flag) = 0;
    288 
    289     /// EmitLinkerOptions - Emit the given list @p Options of strings as linker
    290     /// options into the output.
    291     virtual void EmitLinkerOptions(ArrayRef<std::string> Kind) {}
    292 
    293     /// EmitDataRegion - Note in the output the specified region @p Kind.
    294     virtual void EmitDataRegion(MCDataRegionType Kind) {}
    295 
    296     /// EmitThumbFunc - Note in the output that the specified @p Func is
    297     /// a Thumb mode function (ARM target only).
    298     virtual void EmitThumbFunc(MCSymbol *Func) = 0;
    299 
    300     /// getOrCreateSymbolData - Get symbol data for given symbol.
    301     virtual MCSymbolData &getOrCreateSymbolData(MCSymbol *Symbol);
    302 
    303     /// EmitAssignment - Emit an assignment of @p Value to @p Symbol.
    304     ///
    305     /// This corresponds to an assembler statement such as:
    306     ///  symbol = value
    307     ///
    308     /// The assignment generates no code, but has the side effect of binding the
    309     /// value in the current context. For the assembly streamer, this prints the
    310     /// binding into the .s file.
    311     ///
    312     /// @param Symbol - The symbol being assigned to.
    313     /// @param Value - The value for the symbol.
    314     virtual void EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) = 0;
    315 
    316     /// EmitWeakReference - Emit an weak reference from @p Alias to @p Symbol.
    317     ///
    318     /// This corresponds to an assembler statement such as:
    319     ///  .weakref alias, symbol
    320     ///
    321     /// @param Alias - The alias that is being created.
    322     /// @param Symbol - The symbol being aliased.
    323     virtual void EmitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol) = 0;
    324 
    325     /// EmitSymbolAttribute - Add the given @p Attribute to @p Symbol.
    326     virtual void EmitSymbolAttribute(MCSymbol *Symbol,
    327                                      MCSymbolAttr Attribute) = 0;
    328 
    329     /// EmitSymbolDesc - Set the @p DescValue for the @p Symbol.
    330     ///
    331     /// @param Symbol - The symbol to have its n_desc field set.
    332     /// @param DescValue - The value to set into the n_desc field.
    333     virtual void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) = 0;
    334 
    335     /// BeginCOFFSymbolDef - Start emitting COFF symbol definition
    336     ///
    337     /// @param Symbol - The symbol to have its External & Type fields set.
    338     virtual void BeginCOFFSymbolDef(const MCSymbol *Symbol) = 0;
    339 
    340     /// EmitCOFFSymbolStorageClass - Emit the storage class of the symbol.
    341     ///
    342     /// @param StorageClass - The storage class the symbol should have.
    343     virtual void EmitCOFFSymbolStorageClass(int StorageClass) = 0;
    344 
    345     /// EmitCOFFSymbolType - Emit the type of the symbol.
    346     ///
    347     /// @param Type - A COFF type identifier (see COFF::SymbolType in X86COFF.h)
    348     virtual void EmitCOFFSymbolType(int Type) = 0;
    349 
    350     /// EndCOFFSymbolDef - Marks the end of the symbol definition.
    351     virtual void EndCOFFSymbolDef() = 0;
    352 
    353     /// EmitCOFFSecRel32 - Emits a COFF section relative relocation.
    354     ///
    355     /// @param Symbol - Symbol the section relative realocation should point to.
    356     virtual void EmitCOFFSecRel32(MCSymbol const *Symbol);
    357 
    358     /// EmitELFSize - Emit an ELF .size directive.
    359     ///
    360     /// This corresponds to an assembler statement such as:
    361     ///  .size symbol, expression
    362     ///
    363     virtual void EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) = 0;
    364 
    365     /// EmitCommonSymbol - Emit a common symbol.
    366     ///
    367     /// @param Symbol - The common symbol to emit.
    368     /// @param Size - The size of the common symbol.
    369     /// @param ByteAlignment - The alignment of the symbol if
    370     /// non-zero. This must be a power of 2.
    371     virtual void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
    372                                   unsigned ByteAlignment) = 0;
    373 
    374     /// EmitLocalCommonSymbol - Emit a local common (.lcomm) symbol.
    375     ///
    376     /// @param Symbol - The common symbol to emit.
    377     /// @param Size - The size of the common symbol.
    378     /// @param ByteAlignment - The alignment of the common symbol in bytes.
    379     virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
    380                                        unsigned ByteAlignment) = 0;
    381 
    382     /// EmitZerofill - Emit the zerofill section and an optional symbol.
    383     ///
    384     /// @param Section - The zerofill section to create and or to put the symbol
    385     /// @param Symbol - The zerofill symbol to emit, if non-NULL.
    386     /// @param Size - The size of the zerofill symbol.
    387     /// @param ByteAlignment - The alignment of the zerofill symbol if
    388     /// non-zero. This must be a power of 2 on some targets.
    389     virtual void EmitZerofill(const MCSection *Section, MCSymbol *Symbol = 0,
    390                               uint64_t Size = 0,unsigned ByteAlignment = 0) = 0;
    391 
    392     /// EmitTBSSSymbol - Emit a thread local bss (.tbss) symbol.
    393     ///
    394     /// @param Section - The thread local common section.
    395     /// @param Symbol - The thread local common symbol to emit.
    396     /// @param Size - The size of the symbol.
    397     /// @param ByteAlignment - The alignment of the thread local common symbol
    398     /// if non-zero.  This must be a power of 2 on some targets.
    399     virtual void EmitTBSSSymbol(const MCSection *Section, MCSymbol *Symbol,
    400                                 uint64_t Size, unsigned ByteAlignment = 0) = 0;
    401 
    402     /// @}
    403     /// @name Generating Data
    404     /// @{
    405 
    406     /// EmitBytes - Emit the bytes in \p Data into the output.
    407     ///
    408     /// This is used to implement assembler directives such as .byte, .ascii,
    409     /// etc.
    410     virtual void EmitBytes(StringRef Data) = 0;
    411 
    412     /// EmitValue - Emit the expression @p Value into the output as a native
    413     /// integer of the given @p Size bytes.
    414     ///
    415     /// This is used to implement assembler directives such as .word, .quad,
    416     /// etc.
    417     ///
    418     /// @param Value - The value to emit.
    419     /// @param Size - The size of the integer (in bytes) to emit. This must
    420     /// match a native machine width.
    421     virtual void EmitValueImpl(const MCExpr *Value, unsigned Size) = 0;
    422 
    423     void EmitValue(const MCExpr *Value, unsigned Size);
    424 
    425     /// EmitIntValue - Special case of EmitValue that avoids the client having
    426     /// to pass in a MCExpr for constant integers.
    427     virtual void EmitIntValue(uint64_t Value, unsigned Size);
    428 
    429     /// EmitAbsValue - Emit the Value, but try to avoid relocations. On MachO
    430     /// this is done by producing
    431     /// foo = value
    432     /// .long foo
    433     void EmitAbsValue(const MCExpr *Value, unsigned Size);
    434 
    435     virtual void EmitULEB128Value(const MCExpr *Value) = 0;
    436 
    437     virtual void EmitSLEB128Value(const MCExpr *Value) = 0;
    438 
    439     /// EmitULEB128Value - Special case of EmitULEB128Value that avoids the
    440     /// client having to pass in a MCExpr for constant integers.
    441     void EmitULEB128IntValue(uint64_t Value, unsigned Padding = 0);
    442 
    443     /// EmitSLEB128Value - Special case of EmitSLEB128Value that avoids the
    444     /// client having to pass in a MCExpr for constant integers.
    445     void EmitSLEB128IntValue(int64_t Value);
    446 
    447     /// EmitSymbolValue - Special case of EmitValue that avoids the client
    448     /// having to pass in a MCExpr for MCSymbols.
    449     void EmitSymbolValue(const MCSymbol *Sym, unsigned Size);
    450 
    451     /// EmitGPRel64Value - Emit the expression @p Value into the output as a
    452     /// gprel64 (64-bit GP relative) value.
    453     ///
    454     /// This is used to implement assembler directives such as .gpdword on
    455     /// targets that support them.
    456     virtual void EmitGPRel64Value(const MCExpr *Value);
    457 
    458     /// EmitGPRel32Value - Emit the expression @p Value into the output as a
    459     /// gprel32 (32-bit GP relative) value.
    460     ///
    461     /// This is used to implement assembler directives such as .gprel32 on
    462     /// targets that support them.
    463     virtual void EmitGPRel32Value(const MCExpr *Value);
    464 
    465     /// EmitFill - Emit NumBytes bytes worth of the value specified by
    466     /// FillValue.  This implements directives such as '.space'.
    467     virtual void EmitFill(uint64_t NumBytes, uint8_t FillValue);
    468 
    469     /// \brief Emit NumBytes worth of zeros.
    470     /// This function properly handles data in virtual sections.
    471     virtual void EmitZeros(uint64_t NumBytes);
    472 
    473     /// EmitValueToAlignment - Emit some number of copies of @p Value until
    474     /// the byte alignment @p ByteAlignment is reached.
    475     ///
    476     /// If the number of bytes need to emit for the alignment is not a multiple
    477     /// of @p ValueSize, then the contents of the emitted fill bytes is
    478     /// undefined.
    479     ///
    480     /// This used to implement the .align assembler directive.
    481     ///
    482     /// @param ByteAlignment - The alignment to reach. This must be a power of
    483     /// two on some targets.
    484     /// @param Value - The value to use when filling bytes.
    485     /// @param ValueSize - The size of the integer (in bytes) to emit for
    486     /// @p Value. This must match a native machine width.
    487     /// @param MaxBytesToEmit - The maximum numbers of bytes to emit, or 0. If
    488     /// the alignment cannot be reached in this many bytes, no bytes are
    489     /// emitted.
    490     virtual void EmitValueToAlignment(unsigned ByteAlignment, int64_t Value = 0,
    491                                       unsigned ValueSize = 1,
    492                                       unsigned MaxBytesToEmit = 0) = 0;
    493 
    494     /// EmitCodeAlignment - Emit nops until the byte alignment @p ByteAlignment
    495     /// is reached.
    496     ///
    497     /// This used to align code where the alignment bytes may be executed.  This
    498     /// can emit different bytes for different sizes to optimize execution.
    499     ///
    500     /// @param ByteAlignment - The alignment to reach. This must be a power of
    501     /// two on some targets.
    502     /// @param MaxBytesToEmit - The maximum numbers of bytes to emit, or 0. If
    503     /// the alignment cannot be reached in this many bytes, no bytes are
    504     /// emitted.
    505     virtual void EmitCodeAlignment(unsigned ByteAlignment,
    506                                    unsigned MaxBytesToEmit = 0) = 0;
    507 
    508     /// EmitValueToOffset - Emit some number of copies of @p Value until the
    509     /// byte offset @p Offset is reached.
    510     ///
    511     /// This is used to implement assembler directives such as .org.
    512     ///
    513     /// @param Offset - The offset to reach. This may be an expression, but the
    514     /// expression must be associated with the current section.
    515     /// @param Value - The value to use when filling bytes.
    516     /// @return false on success, true if the offset was invalid.
    517     virtual bool EmitValueToOffset(const MCExpr *Offset,
    518                                    unsigned char Value = 0) = 0;
    519 
    520     /// @}
    521 
    522     /// EmitFileDirective - Switch to a new logical file.  This is used to
    523     /// implement the '.file "foo.c"' assembler directive.
    524     virtual void EmitFileDirective(StringRef Filename) = 0;
    525 
    526     /// EmitDwarfFileDirective - Associate a filename with a specified logical
    527     /// file number.  This implements the DWARF2 '.file 4 "foo.c"' assembler
    528     /// directive.
    529     virtual bool EmitDwarfFileDirective(unsigned FileNo, StringRef Directory,
    530                                         StringRef Filename, unsigned CUID = 0);
    531 
    532     /// EmitDwarfLocDirective - This implements the DWARF2
    533     // '.loc fileno lineno ...' assembler directive.
    534     virtual void EmitDwarfLocDirective(unsigned FileNo, unsigned Line,
    535                                        unsigned Column, unsigned Flags,
    536                                        unsigned Isa,
    537                                        unsigned Discriminator,
    538                                        StringRef FileName);
    539 
    540     virtual void EmitDwarfAdvanceLineAddr(int64_t LineDelta,
    541                                           const MCSymbol *LastLabel,
    542                                           const MCSymbol *Label,
    543                                           unsigned PointerSize) = 0;
    544 
    545     virtual void EmitDwarfAdvanceFrameAddr(const MCSymbol *LastLabel,
    546                                            const MCSymbol *Label) {
    547     }
    548 
    549     void EmitDwarfSetLineAddr(int64_t LineDelta, const MCSymbol *Label,
    550                               int PointerSize);
    551 
    552     virtual void EmitCompactUnwindEncoding(uint32_t CompactUnwindEncoding);
    553     virtual void EmitCFISections(bool EH, bool Debug);
    554     void EmitCFIStartProc();
    555     void EmitCFIEndProc();
    556     virtual void EmitCFIDefCfa(int64_t Register, int64_t Offset);
    557     virtual void EmitCFIDefCfaOffset(int64_t Offset);
    558     virtual void EmitCFIDefCfaRegister(int64_t Register);
    559     virtual void EmitCFIOffset(int64_t Register, int64_t Offset);
    560     virtual void EmitCFIPersonality(const MCSymbol *Sym, unsigned Encoding);
    561     virtual void EmitCFILsda(const MCSymbol *Sym, unsigned Encoding);
    562     virtual void EmitCFIRememberState();
    563     virtual void EmitCFIRestoreState();
    564     virtual void EmitCFISameValue(int64_t Register);
    565     virtual void EmitCFIRestore(int64_t Register);
    566     virtual void EmitCFIRelOffset(int64_t Register, int64_t Offset);
    567     virtual void EmitCFIAdjustCfaOffset(int64_t Adjustment);
    568     virtual void EmitCFIEscape(StringRef Values);
    569     virtual void EmitCFISignalFrame();
    570     virtual void EmitCFIUndefined(int64_t Register);
    571     virtual void EmitCFIRegister(int64_t Register1, int64_t Register2);
    572 
    573     virtual void EmitWin64EHStartProc(const MCSymbol *Symbol);
    574     virtual void EmitWin64EHEndProc();
    575     virtual void EmitWin64EHStartChained();
    576     virtual void EmitWin64EHEndChained();
    577     virtual void EmitWin64EHHandler(const MCSymbol *Sym, bool Unwind,
    578                                     bool Except);
    579     virtual void EmitWin64EHHandlerData();
    580     virtual void EmitWin64EHPushReg(unsigned Register);
    581     virtual void EmitWin64EHSetFrame(unsigned Register, unsigned Offset);
    582     virtual void EmitWin64EHAllocStack(unsigned Size);
    583     virtual void EmitWin64EHSaveReg(unsigned Register, unsigned Offset);
    584     virtual void EmitWin64EHSaveXMM(unsigned Register, unsigned Offset);
    585     virtual void EmitWin64EHPushFrame(bool Code);
    586     virtual void EmitWin64EHEndProlog();
    587 
    588     /// EmitInstruction - Emit the given @p Instruction into the current
    589     /// section.
    590     virtual void EmitInstruction(const MCInst &Inst) = 0;
    591 
    592     /// \brief Set the bundle alignment mode from now on in the section.
    593     /// The argument is the power of 2 to which the alignment is set. The
    594     /// value 0 means turn the bundle alignment off.
    595     virtual void EmitBundleAlignMode(unsigned AlignPow2) = 0;
    596 
    597     /// \brief The following instructions are a bundle-locked group.
    598     ///
    599     /// \param AlignToEnd - If true, the bundle-locked group will be aligned to
    600     ///                     the end of a bundle.
    601     virtual void EmitBundleLock(bool AlignToEnd) = 0;
    602 
    603     /// \brief Ends a bundle-locked group.
    604     virtual void EmitBundleUnlock() = 0;
    605 
    606     /// EmitRawText - If this file is backed by a assembly streamer, this dumps
    607     /// the specified string in the output .s file.  This capability is
    608     /// indicated by the hasRawTextSupport() predicate.  By default this aborts.
    609     virtual void EmitRawText(StringRef String);
    610     void EmitRawText(const Twine &String);
    611 
    612     /// ARM-related methods.
    613     /// FIXME: Eventually we should have some "target MC streamer" and move
    614     /// these methods there.
    615     virtual void EmitFnStart();
    616     virtual void EmitFnEnd();
    617     virtual void EmitCantUnwind();
    618     virtual void EmitPersonality(const MCSymbol *Personality);
    619     virtual void EmitHandlerData();
    620     virtual void EmitSetFP(unsigned FpReg, unsigned SpReg, int64_t Offset = 0);
    621     virtual void EmitPad(int64_t Offset);
    622     virtual void EmitRegSave(const SmallVectorImpl<unsigned> &RegList,
    623                              bool isVector);
    624 
    625     /// PPC-related methods.
    626     /// FIXME: Eventually replace it with some "target MC streamer" and move
    627     /// these methods there.
    628     virtual void EmitTCEntry(const MCSymbol &S);
    629 
    630     /// FinishImpl - Streamer specific finalization.
    631     virtual void FinishImpl() = 0;
    632     /// Finish - Finish emission of machine code.
    633     void Finish();
    634   };
    635 
    636   /// createNullStreamer - Create a dummy machine code streamer, which does
    637   /// nothing. This is useful for timing the assembler front end.
    638   MCStreamer *createNullStreamer(MCContext &Ctx);
    639 
    640   /// createAsmStreamer - Create a machine code streamer which will print out
    641   /// assembly for the native target, suitable for compiling with a native
    642   /// assembler.
    643   ///
    644   /// \param InstPrint - If given, the instruction printer to use. If not given
    645   /// the MCInst representation will be printed.  This method takes ownership of
    646   /// InstPrint.
    647   ///
    648   /// \param CE - If given, a code emitter to use to show the instruction
    649   /// encoding inline with the assembly. This method takes ownership of \p CE.
    650   ///
    651   /// \param TAB - If given, a target asm backend to use to show the fixup
    652   /// information in conjunction with encoding information. This method takes
    653   /// ownership of \p TAB.
    654   ///
    655   /// \param ShowInst - Whether to show the MCInst representation inline with
    656   /// the assembly.
    657   MCStreamer *createAsmStreamer(MCContext &Ctx, formatted_raw_ostream &OS,
    658                                 bool isVerboseAsm,
    659                                 bool useLoc,
    660                                 bool useCFI,
    661                                 bool useDwarfDirectory,
    662                                 MCInstPrinter *InstPrint = 0,
    663                                 MCCodeEmitter *CE = 0,
    664                                 MCAsmBackend *TAB = 0,
    665                                 bool ShowInst = false);
    666 
    667   /// createMachOStreamer - Create a machine code streamer which will generate
    668   /// Mach-O format object files.
    669   ///
    670   /// Takes ownership of \p TAB and \p CE.
    671   MCStreamer *createMachOStreamer(MCContext &Ctx, MCAsmBackend &TAB,
    672                                   raw_ostream &OS, MCCodeEmitter *CE,
    673                                   bool RelaxAll = false);
    674 
    675   /// createWinCOFFStreamer - Create a machine code streamer which will
    676   /// generate Microsoft COFF format object files.
    677   ///
    678   /// Takes ownership of \p TAB and \p CE.
    679   MCStreamer *createWinCOFFStreamer(MCContext &Ctx,
    680                                     MCAsmBackend &TAB,
    681                                     MCCodeEmitter &CE, raw_ostream &OS,
    682                                     bool RelaxAll = false);
    683 
    684   /// createELFStreamer - Create a machine code streamer which will generate
    685   /// ELF format object files.
    686   MCStreamer *createELFStreamer(MCContext &Ctx, MCAsmBackend &TAB,
    687                                 raw_ostream &OS, MCCodeEmitter *CE,
    688                                 bool RelaxAll, bool NoExecStack);
    689 
    690   /// createPureStreamer - Create a machine code streamer which will generate
    691   /// "pure" MC object files, for use with MC-JIT and testing tools.
    692   ///
    693   /// Takes ownership of \p TAB and \p CE.
    694   MCStreamer *createPureStreamer(MCContext &Ctx, MCAsmBackend &TAB,
    695                                  raw_ostream &OS, MCCodeEmitter *CE);
    696 
    697 } // end namespace llvm
    698 
    699 #endif
    700