include/llvm/MC/MCStreamer.h - platform/external/llvm - Gitiles

 //===- MCStreamer.h - High-level Streaming Machine Code Output --*- C++ -*-===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//
 //
 // This file declares the MCStreamer class.
 //
 //===----------------------------------------------------------------------===//

 #ifndef LLVM_MC_MCSTREAMER_H
 #define LLVM_MC_MCSTREAMER_H

 #include "llvm/System/DataTypes.h"
 #include "llvm/MC/MCDirectives.h"

 namespace llvm {
   class MCAsmInfo;
   class MCCodeEmitter;
   class MCContext;
   class MCExpr;
   class MCInst;
   class MCInstPrinter;
   class MCSection;
   class MCSymbol;
   class StringRef;
   class Twine;
   class raw_ostream;
   class formatted_raw_ostream;

   /// MCStreamer - Streaming machine code generation interface.  This interface
   /// is intended to provide a programatic interface that is very similar to the
   /// level that an assembler .s file provides.  It has callbacks to emit bytes,
   /// handle directives, etc.  The implementation of this interface retains
   /// state to know what the current section is etc.
   ///
   /// There are multiple implementations of this interface: one for writing out
   /// a .s file, and implementations that write out .o files of various formats.
   ///
   class MCStreamer {
     MCContext &Context;

     MCStreamer(const MCStreamer&); // DO NOT IMPLEMENT
     MCStreamer &operator=(const MCStreamer&); // DO NOT IMPLEMENT

   protected:
     MCStreamer(MCContext &Ctx);

     /// CurSection - This is the current section code is being emitted to, it is
     /// kept up to date by SwitchSection.
     const MCSection *CurSection;

   public:
     virtual ~MCStreamer();

     MCContext &getContext() const { return Context; }

     /// @name Assembly File Formatting.
     /// @{

     /// isVerboseAsm - Return true if this streamer supports verbose assembly at
     /// all.
     virtual bool isVerboseAsm() const { return false; }

     /// AddComment - Add a comment that can be emitted to the generated .s
     /// file if applicable as a QoI issue to make the output of the compiler
     /// more readable.  This only affects the MCAsmStreamer, and only when
     /// verbose assembly output is enabled.
     ///
     /// If the comment includes embedded \n's, they will each get the comment
     /// prefix as appropriate.  The added comment should not end with a \n.
     virtual void AddComment(const Twine &T) {}

     /// GetCommentOS - Return a raw_ostream that comments can be written to.
     /// Unlike AddComment, you are required to terminate comments with \n if you
     /// use this method.
     virtual raw_ostream &GetCommentOS();

     /// AddBlankLine - Emit a blank line to a .s file to pretty it up.
     virtual void AddBlankLine() {}

     /// @}

     /// @name Symbol & Section Management
     /// @{

     /// getCurrentSection - Return the current seciton that the streamer is
     /// emitting code to.
     const MCSection *getCurrentSection() const { return CurSection; }

     /// SwitchSection - Set the current section where code is being emitted to
     /// @p Section.  This is required to update CurSection.
     ///
     /// This corresponds to assembler directives like .section, .text, etc.
     virtual void SwitchSection(const MCSection *Section) = 0;

     /// EmitLabel - Emit a label for @p Symbol into the current section.
     ///
     /// This corresponds to an assembler statement such as:
     ///   foo:
     ///
     /// @param Symbol - The symbol to emit. A given symbol should only be
     /// emitted as a label once, and symbols emitted as a label should never be
     /// used in an assignment.
     virtual void EmitLabel(MCSymbol *Symbol) = 0;

     /// EmitAssemblerFlag - Note in the output the specified @p Flag
     virtual void EmitAssemblerFlag(MCAssemblerFlag Flag) = 0;

     /// EmitAssignment - Emit an assignment of @p Value to @p Symbol.
     ///
     /// This corresponds to an assembler statement such as:
     ///  symbol = value
     ///
     /// The assignment generates no code, but has the side effect of binding the
     /// value in the current context. For the assembly streamer, this prints the
     /// binding into the .s file.
     ///
     /// @param Symbol - The symbol being assigned to.
     /// @param Value - The value for the symbol.
     virtual void EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) = 0;

     /// EmitSymbolAttribute - Add the given @p Attribute to @p Symbol.
     virtual void EmitSymbolAttribute(MCSymbol *Symbol,
                                      MCSymbolAttr Attribute) = 0;

     /// EmitSymbolDesc - Set the @p DescValue for the @p Symbol.
     ///
     /// @param Symbol - The symbol to have its n_desc field set.
     /// @param DescValue - The value to set into the n_desc field.
     virtual void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) = 0;


     /// EmitELFSize - Emit an ELF .size directive.
     ///
     /// This corresponds to an assembler statement such as:
     ///  .size symbol, expression
     ///
     virtual void EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) = 0;

     /// EmitCommonSymbol - Emit a common symbol.
     ///
     /// @param Symbol - The common symbol to emit.
     /// @param Size - The size of the common symbol.
     /// @param ByteAlignment - The alignment of the symbol if
     /// non-zero. This must be a power of 2.
     virtual void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
                                   unsigned ByteAlignment) = 0;

     /// EmitLocalCommonSymbol - Emit a local common (.lcomm) symbol.
     ///
     /// @param Symbol - The common symbol to emit.
     /// @param Size - The size of the common symbol.
     virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size) = 0;

     /// EmitZerofill - Emit a the zerofill section and an option symbol.
     ///
     /// @param Section - The zerofill section to create and or to put the symbol
     /// @param Symbol - The zerofill symbol to emit, if non-NULL.
     /// @param Size - The size of the zerofill symbol.
     /// @param ByteAlignment - The alignment of the zerofill symbol if
     /// non-zero. This must be a power of 2 on some targets.
     virtual void EmitZerofill(const MCSection *Section, MCSymbol *Symbol = 0,
                               unsigned Size = 0,unsigned ByteAlignment = 0) = 0;

     /// @}
     /// @name Generating Data
     /// @{

     /// EmitBytes - Emit the bytes in \arg Data into the output.
     ///
     /// This is used to implement assembler directives such as .byte, .ascii,
     /// etc.
     virtual void EmitBytes(StringRef Data, unsigned AddrSpace) = 0;

     /// EmitValue - Emit the expression @p Value into the output as a native
     /// integer of the given @p Size bytes.
     ///
     /// This is used to implement assembler directives such as .word, .quad,
     /// etc.
     ///
     /// @param Value - The value to emit.
     /// @param Size - The size of the integer (in bytes) to emit. This must
     /// match a native machine width.
     virtual void EmitValue(const MCExpr *Value, unsigned Size,
                            unsigned AddrSpace) = 0;

     /// EmitIntValue - Special case of EmitValue that avoids the client having
     /// to pass in a MCExpr for constant integers.
     virtual void EmitIntValue(uint64_t Value, unsigned Size,unsigned AddrSpace);

     /// EmitGPRel32Value - Emit the expression @p Value into the output as a
     /// gprel32 (32-bit GP relative) value.
     ///
     /// This is used to implement assembler directives such as .gprel32 on
     /// targets that support them.
     virtual void EmitGPRel32Value(const MCExpr *Value) = 0;

     /// EmitFill - Emit NumBytes bytes worth of the value specified by
     /// FillValue.  This implements directives such as '.space'.
     virtual void EmitFill(uint64_t NumBytes, uint8_t FillValue,
                           unsigned AddrSpace);

     /// EmitZeros - Emit NumBytes worth of zeros.  This is a convenience
     /// function that just wraps EmitFill.
     void EmitZeros(uint64_t NumBytes, unsigned AddrSpace) {
       EmitFill(NumBytes, 0, AddrSpace);
     }


     /// EmitValueToAlignment - Emit some number of copies of @p Value until
     /// the byte alignment @p ByteAlignment is reached.
     ///
     /// If the number of bytes need to emit for the alignment is not a multiple
     /// of @p ValueSize, then the contents of the emitted fill bytes is
     /// undefined.
     ///
     /// This used to implement the .align assembler directive.
     ///
     /// @param ByteAlignment - The alignment to reach. This must be a power of
     /// two on some targets.
     /// @param Value - The value to use when filling bytes.
     /// @param ValueSize - The size of the integer (in bytes) to emit for
     /// @p Value. This must match a native machine width.
     /// @param MaxBytesToEmit - The maximum numbers of bytes to emit, or 0. If
     /// the alignment cannot be reached in this many bytes, no bytes are
     /// emitted.
     virtual void EmitValueToAlignment(unsigned ByteAlignment, int64_t Value = 0,
                                       unsigned ValueSize = 1,
                                       unsigned MaxBytesToEmit = 0) = 0;

     /// EmitCodeAlignment - Emit nops until the byte alignment @p ByteAlignment
     /// is reached.
     ///
     /// This used to align code where the alignment bytes may be executed.  This
     /// can emit different bytes for different sizes to optimize execution.
     ///
     /// @param ByteAlignment - The alignment to reach. This must be a power of
     /// two on some targets.
     /// @param MaxBytesToEmit - The maximum numbers of bytes to emit, or 0. If
     /// the alignment cannot be reached in this many bytes, no bytes are
     /// emitted.
     virtual void EmitCodeAlignment(unsigned ByteAlignment,
                                    unsigned MaxBytesToEmit = 0) = 0;

     /// EmitValueToOffset - Emit some number of copies of @p Value until the
     /// byte offset @p Offset is reached.
     ///
     /// This is used to implement assembler directives such as .org.
     ///
     /// @param Offset - The offset to reach. This may be an expression, but the
     /// expression must be associated with the current section.
     /// @param Value - The value to use when filling bytes.
     virtual void EmitValueToOffset(const MCExpr *Offset,
                                    unsigned char Value = 0) = 0;

     /// @}

     /// EmitFileDirective - Switch to a new logical file.  This is used to
     /// implement the '.file "foo.c"' assembler directive.
     virtual void EmitFileDirective(StringRef Filename) = 0;

     /// EmitDwarfFileDirective - Associate a filename with a specified logical
     /// file number.  This implements the DWARF2 '.file 4 "foo.c"' assembler
     /// directive.
     virtual void EmitDwarfFileDirective(unsigned FileNo,StringRef Filename) = 0;

     /// EmitInstruction - Emit the given @p Instruction into the current
     /// section.
     virtual void EmitInstruction(const MCInst &Inst) = 0;

     /// Finish - Finish emission of machine code and flush any output.
     virtual void Finish() = 0;
   };

   /// createNullStreamer - Create a dummy machine code streamer, which does
   /// nothing. This is useful for timing the assembler front end.
   MCStreamer *createNullStreamer(MCContext &Ctx);

   /// createAsmStreamer - Create a machine code streamer which will print out
   /// assembly for the native target, suitable for compiling with a native
   /// assembler.
   ///
   /// \param InstPrint - If given, the instruction printer to use. If not given
   /// the MCInst representation will be printed.
   ///
   /// \param CE - If given, a code emitter to use to show the instruction
   /// encoding inline with the assembly.
   ///
   /// \param ShowInst - Whether to show the MCInst representation inline with
   /// the assembly.
   MCStreamer *createAsmStreamer(MCContext &Ctx, formatted_raw_ostream &OS,
                                 const MCAsmInfo &MAI, bool isLittleEndian,
                                 bool isVerboseAsm,
                                 MCInstPrinter *InstPrint = 0,
                                 MCCodeEmitter *CE = 0,
                                 bool ShowInst = false);

   // FIXME: These two may end up getting rolled into a single
   // createObjectStreamer interface, which implements the assembler backend, and
   // is parameterized on an output object file writer.

   /// createMachOStream - Create a machine code streamer which will generative
   /// Mach-O format object files.
   MCStreamer *createMachOStreamer(MCContext &Ctx, raw_ostream &OS,
                                   MCCodeEmitter *CE);

   /// createELFStreamer - Create a machine code streamer which will generative
   /// ELF format object files.
   MCStreamer *createELFStreamer(MCContext &Ctx, raw_ostream &OS);

 } // end namespace llvm

 #endif
	//===- MCStreamer.h - High-level Streaming Machine Code Output --- C++ --===//
	//
	// The LLVM Compiler Infrastructure
	//
	// This file is distributed under the University of Illinois Open Source
	// License. See LICENSE.TXT for details.
	//
	//===----------------------------------------------------------------------===//
	//
	// This file declares the MCStreamer class.
	//
	//===----------------------------------------------------------------------===//

	#ifndef LLVM_MC_MCSTREAMER_H
	#define LLVM_MC_MCSTREAMER_H

	#include "llvm/System/DataTypes.h"
	#include "llvm/MC/MCDirectives.h"

	namespace llvm {
	class MCAsmInfo;
	class MCCodeEmitter;
	class MCContext;
	class MCExpr;
	class MCInst;
	class MCInstPrinter;
	class MCSection;
	class MCSymbol;
	class StringRef;
	class Twine;
	class raw_ostream;
	class formatted_raw_ostream;

	/// MCStreamer - Streaming machine code generation interface. This interface
	/// is intended to provide a programatic interface that is very similar to the
	/// level that an assembler .s file provides. It has callbacks to emit bytes,
	/// handle directives, etc. The implementation of this interface retains
	/// state to know what the current section is etc.
	///
	/// There are multiple implementations of this interface: one for writing out
	/// a .s file, and implementations that write out .o files of various formats.
	///
	class MCStreamer {
	MCContext &Context;

	MCStreamer(const MCStreamer&); // DO NOT IMPLEMENT
	MCStreamer &operator=(const MCStreamer&); // DO NOT IMPLEMENT

	protected:
	MCStreamer(MCContext &Ctx);

	/// CurSection - This is the current section code is being emitted to, it is
	/// kept up to date by SwitchSection.
	const MCSection *CurSection;

	public:
	virtual ~MCStreamer();

	MCContext &getContext() const { return Context; }

	/// @name Assembly File Formatting.
	/// @{

	/// isVerboseAsm - Return true if this streamer supports verbose assembly at
	/// all.
	virtual bool isVerboseAsm() const { return false; }

	/// AddComment - Add a comment that can be emitted to the generated .s
	/// file if applicable as a QoI issue to make the output of the compiler
	/// more readable. This only affects the MCAsmStreamer, and only when
	/// verbose assembly output is enabled.
	///
	/// If the comment includes embedded \n's, they will each get the comment
	/// prefix as appropriate. The added comment should not end with a \n.
	virtual void AddComment(const Twine &T) {}

	/// GetCommentOS - Return a raw_ostream that comments can be written to.
	/// Unlike AddComment, you are required to terminate comments with \n if you
	/// use this method.
	virtual raw_ostream &GetCommentOS();

	/// AddBlankLine - Emit a blank line to a .s file to pretty it up.
	virtual void AddBlankLine() {}

	/// @}

	/// @name Symbol & Section Management
	/// @{

	/// getCurrentSection - Return the current seciton that the streamer is
	/// emitting code to.
	const MCSection *getCurrentSection() const { return CurSection; }

	/// SwitchSection - Set the current section where code is being emitted to
	/// @p Section. This is required to update CurSection.
	///
	/// This corresponds to assembler directives like .section, .text, etc.
	virtual void SwitchSection(const MCSection *Section) = 0;

	/// EmitLabel - Emit a label for @p Symbol into the current section.
	///
	/// This corresponds to an assembler statement such as:
	/// foo:
	///
	/// @param Symbol - The symbol to emit. A given symbol should only be
	/// emitted as a label once, and symbols emitted as a label should never be
	/// used in an assignment.
	virtual void EmitLabel(MCSymbol *Symbol) = 0;

	/// EmitAssemblerFlag - Note in the output the specified @p Flag
	virtual void EmitAssemblerFlag(MCAssemblerFlag Flag) = 0;

	/// EmitAssignment - Emit an assignment of @p Value to @p Symbol.
	///
	/// This corresponds to an assembler statement such as:
	/// symbol = value
	///
	/// The assignment generates no code, but has the side effect of binding the
	/// value in the current context. For the assembly streamer, this prints the
	/// binding into the .s file.
	///
	/// @param Symbol - The symbol being assigned to.
	/// @param Value - The value for the symbol.
	virtual void EmitAssignment(MCSymbol Symbol, const MCExpr Value) = 0;

	/// EmitSymbolAttribute - Add the given @p Attribute to @p Symbol.
	virtual void EmitSymbolAttribute(MCSymbol *Symbol,
	MCSymbolAttr Attribute) = 0;

	/// EmitSymbolDesc - Set the @p DescValue for the @p Symbol.
	///
	/// @param Symbol - The symbol to have its n_desc field set.
	/// @param DescValue - The value to set into the n_desc field.
	virtual void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) = 0;


	/// EmitELFSize - Emit an ELF .size directive.
	///
	/// This corresponds to an assembler statement such as:
	/// .size symbol, expression
	///
	virtual void EmitELFSize(MCSymbol Symbol, const MCExpr Value) = 0;

	/// EmitCommonSymbol - Emit a common symbol.
	///
	/// @param Symbol - The common symbol to emit.
	/// @param Size - The size of the common symbol.
	/// @param ByteAlignment - The alignment of the symbol if
	/// non-zero. This must be a power of 2.
	virtual void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
	unsigned ByteAlignment) = 0;

	/// EmitLocalCommonSymbol - Emit a local common (.lcomm) symbol.
	///
	/// @param Symbol - The common symbol to emit.
	/// @param Size - The size of the common symbol.
	virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size) = 0;

	/// EmitZerofill - Emit a the zerofill section and an option symbol.
	///
	/// @param Section - The zerofill section to create and or to put the symbol
	/// @param Symbol - The zerofill symbol to emit, if non-NULL.
	/// @param Size - The size of the zerofill symbol.
	/// @param ByteAlignment - The alignment of the zerofill symbol if
	/// non-zero. This must be a power of 2 on some targets.
	virtual void EmitZerofill(const MCSection Section, MCSymbol Symbol = 0,
	unsigned Size = 0,unsigned ByteAlignment = 0) = 0;

	/// @}
	/// @name Generating Data
	/// @{

	/// EmitBytes - Emit the bytes in \arg Data into the output.
	///
	/// This is used to implement assembler directives such as .byte, .ascii,
	/// etc.
	virtual void EmitBytes(StringRef Data, unsigned AddrSpace) = 0;

	/// EmitValue - Emit the expression @p Value into the output as a native
	/// integer of the given @p Size bytes.
	///
	/// This is used to implement assembler directives such as .word, .quad,
	/// etc.
	///
	/// @param Value - The value to emit.
	/// @param Size - The size of the integer (in bytes) to emit. This must
	/// match a native machine width.
	virtual void EmitValue(const MCExpr *Value, unsigned Size,
	unsigned AddrSpace) = 0;

	/// EmitIntValue - Special case of EmitValue that avoids the client having
	/// to pass in a MCExpr for constant integers.
	virtual void EmitIntValue(uint64_t Value, unsigned Size,unsigned AddrSpace);

	/// EmitGPRel32Value - Emit the expression @p Value into the output as a
	/// gprel32 (32-bit GP relative) value.
	///
	/// This is used to implement assembler directives such as .gprel32 on
	/// targets that support them.
	virtual void EmitGPRel32Value(const MCExpr *Value) = 0;

	/// EmitFill - Emit NumBytes bytes worth of the value specified by
	/// FillValue. This implements directives such as '.space'.
	virtual void EmitFill(uint64_t NumBytes, uint8_t FillValue,
	unsigned AddrSpace);

	/// EmitZeros - Emit NumBytes worth of zeros. This is a convenience
	/// function that just wraps EmitFill.
	void EmitZeros(uint64_t NumBytes, unsigned AddrSpace) {
	EmitFill(NumBytes, 0, AddrSpace);
	}


	/// EmitValueToAlignment - Emit some number of copies of @p Value until
	/// the byte alignment @p ByteAlignment is reached.
	///
	/// If the number of bytes need to emit for the alignment is not a multiple
	/// of @p ValueSize, then the contents of the emitted fill bytes is
	/// undefined.
	///
	/// This used to implement the .align assembler directive.
	///
	/// @param ByteAlignment - The alignment to reach. This must be a power of
	/// two on some targets.
	/// @param Value - The value to use when filling bytes.
	/// @param ValueSize - The size of the integer (in bytes) to emit for
	/// @p Value. This must match a native machine width.
	/// @param MaxBytesToEmit - The maximum numbers of bytes to emit, or 0. If
	/// the alignment cannot be reached in this many bytes, no bytes are
	/// emitted.
	virtual void EmitValueToAlignment(unsigned ByteAlignment, int64_t Value = 0,
	unsigned ValueSize = 1,
	unsigned MaxBytesToEmit = 0) = 0;

	/// EmitCodeAlignment - Emit nops until the byte alignment @p ByteAlignment
	/// is reached.
	///
	/// This used to align code where the alignment bytes may be executed. This
	/// can emit different bytes for different sizes to optimize execution.
	///
	/// @param ByteAlignment - The alignment to reach. This must be a power of
	/// two on some targets.
	/// @param MaxBytesToEmit - The maximum numbers of bytes to emit, or 0. If
	/// the alignment cannot be reached in this many bytes, no bytes are
	/// emitted.
	virtual void EmitCodeAlignment(unsigned ByteAlignment,
	unsigned MaxBytesToEmit = 0) = 0;

	/// EmitValueToOffset - Emit some number of copies of @p Value until the
	/// byte offset @p Offset is reached.
	///
	/// This is used to implement assembler directives such as .org.
	///
	/// @param Offset - The offset to reach. This may be an expression, but the
	/// expression must be associated with the current section.
	/// @param Value - The value to use when filling bytes.
	virtual void EmitValueToOffset(const MCExpr *Offset,
	unsigned char Value = 0) = 0;

	/// @}

	/// EmitFileDirective - Switch to a new logical file. This is used to
	/// implement the '.file "foo.c"' assembler directive.
	virtual void EmitFileDirective(StringRef Filename) = 0;

	/// EmitDwarfFileDirective - Associate a filename with a specified logical
	/// file number. This implements the DWARF2 '.file 4 "foo.c"' assembler
	/// directive.
	virtual void EmitDwarfFileDirective(unsigned FileNo,StringRef Filename) = 0;

	/// EmitInstruction - Emit the given @p Instruction into the current
	/// section.
	virtual void EmitInstruction(const MCInst &Inst) = 0;

	/// Finish - Finish emission of machine code and flush any output.
	virtual void Finish() = 0;
	};

	/// createNullStreamer - Create a dummy machine code streamer, which does
	/// nothing. This is useful for timing the assembler front end.
	MCStreamer *createNullStreamer(MCContext &Ctx);

	/// createAsmStreamer - Create a machine code streamer which will print out
	/// assembly for the native target, suitable for compiling with a native
	/// assembler.
	///
	/// \param InstPrint - If given, the instruction printer to use. If not given
	/// the MCInst representation will be printed.
	///
	/// \param CE - If given, a code emitter to use to show the instruction
	/// encoding inline with the assembly.
	///
	/// \param ShowInst - Whether to show the MCInst representation inline with
	/// the assembly.
	MCStreamer *createAsmStreamer(MCContext &Ctx, formatted_raw_ostream &OS,
	const MCAsmInfo &MAI, bool isLittleEndian,
	bool isVerboseAsm,
	MCInstPrinter *InstPrint = 0,
	MCCodeEmitter *CE = 0,
	bool ShowInst = false);

	// FIXME: These two may end up getting rolled into a single
	// createObjectStreamer interface, which implements the assembler backend, and
	// is parameterized on an output object file writer.

	/// createMachOStream - Create a machine code streamer which will generative
	/// Mach-O format object files.
	MCStreamer *createMachOStreamer(MCContext &Ctx, raw_ostream &OS,
	MCCodeEmitter *CE);

	/// createELFStreamer - Create a machine code streamer which will generative
	/// ELF format object files.
	MCStreamer *createELFStreamer(MCContext &Ctx, raw_ostream &OS);

	} // end namespace llvm

	#endif