include/llvm/MC/MCStreamer.h

   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/System/DataTypes.h"
  18 #include "llvm/MC/MCDirectives.h"
  19
  20 namespace llvm {
  21   class MCAsmInfo;
  22   class MCCodeEmitter;
  23   class MCContext;
  24   class MCExpr;
  25   class MCInst;
  26   class MCInstPrinter;
  27   class MCSection;
  28   class MCSymbol;
  29   class StringRef;
  30   class TargetAsmBackend;
  31   class Twine;
  32   class raw_ostream;
  33   class formatted_raw_ostream;
  34
  35   /// MCStreamer - Streaming machine code generation interface.  This interface
  36   /// is intended to provide a programatic interface that is very similar to the
  37   /// level that an assembler .s file provides.  It has callbacks to emit bytes,
  38   /// handle directives, etc.  The implementation of this interface retains
  39   /// state to know what the current section is etc.
  40   ///
  41   /// There are multiple implementations of this interface: one for writing out
  42   /// a .s file, and implementations that write out .o files of various formats.
  43   ///
  44   class MCStreamer {
  45     MCContext &Context;
  46
  47     MCStreamer(const MCStreamer&); // DO NOT IMPLEMENT
  48     MCStreamer &operator=(const MCStreamer&); // DO NOT IMPLEMENT
  49
  50   protected:
  51     MCStreamer(MCContext &Ctx);
  52
  53     /// CurSection - This is the current section code is being emitted to, it is
  54     /// kept up to date by SwitchSection.
  55     const MCSection *CurSection;
  56
  57   public:
  58     virtual ~MCStreamer();
  59
  60     MCContext &getContext() const { return Context; }
  61
  62     /// @name Assembly File Formatting.
  63     /// @{
  64
  65     /// isVerboseAsm - Return true if this streamer supports verbose assembly
  66     /// and if it is enabled.
  67     virtual bool isVerboseAsm() const { return false; }
  68
  69     /// hasRawTextSupport - Return true if this asm streamer supports emitting
  70     /// unformatted text to the .s file with EmitRawText.
  71     virtual bool hasRawTextSupport() const { return false; }
  72
  73     /// AddComment - Add a comment that can be emitted to the generated .s
  74     /// file if applicable as a QoI issue to make the output of the compiler
  75     /// more readable.  This only affects the MCAsmStreamer, and only when
  76     /// verbose assembly output is enabled.
  77     ///
  78     /// If the comment includes embedded \n's, they will each get the comment
  79     /// prefix as appropriate.  The added comment should not end with a \n.
  80     virtual void AddComment(const Twine &T) {}
  81
  82     /// GetCommentOS - Return a raw_ostream that comments can be written to.
  83     /// Unlike AddComment, you are required to terminate comments with \n if you
  84     /// use this method.
  85     virtual raw_ostream &GetCommentOS();
  86
  87     /// AddBlankLine - Emit a blank line to a .s file to pretty it up.
  88     virtual void AddBlankLine() {}
  89
  90     /// @}
  91
  92     /// @name Symbol & Section Management
  93     /// @{
  94
  95     /// getCurrentSection - Return the current section that the streamer is
  96     /// emitting code to.
  97     const MCSection *getCurrentSection() const { return CurSection; }
  98
  99     /// SwitchSection - Set the current section where code is being emitted to
 100     /// @p Section.  This is required to update CurSection.
 101     ///
 102     /// This corresponds to assembler directives like .section, .text, etc.
 103     virtual void SwitchSection(const MCSection *Section) = 0;
 104
 105     /// EmitLabel - Emit a label for @p Symbol into the current section.
 106     ///
 107     /// This corresponds to an assembler statement such as:
 108     ///   foo:
 109     ///
 110     /// @param Symbol - The symbol to emit. A given symbol should only be
 111     /// emitted as a label once, and symbols emitted as a label should never be
 112     /// used in an assignment.
 113     virtual void EmitLabel(MCSymbol *Symbol) = 0;
 114
 115     /// EmitAssemblerFlag - Note in the output the specified @p Flag
 116     virtual void EmitAssemblerFlag(MCAssemblerFlag Flag) = 0;
 117
 118     /// EmitAssignment - Emit an assignment of @p Value to @p Symbol.
 119     ///
 120     /// This corresponds to an assembler statement such as:
 121     ///  symbol = value
 122     ///
 123     /// The assignment generates no code, but has the side effect of binding the
 124     /// value in the current context. For the assembly streamer, this prints the
 125     /// binding into the .s file.
 126     ///
 127     /// @param Symbol - The symbol being assigned to.
 128     /// @param Value - The value for the symbol.
 129     virtual void EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) = 0;
 130
 131     /// EmitSymbolAttribute - Add the given @p Attribute to @p Symbol.
 132     virtual void EmitSymbolAttribute(MCSymbol *Symbol,
 133                                      MCSymbolAttr Attribute) = 0;
 134
 135     /// EmitSymbolDesc - Set the @p DescValue for the @p Symbol.
 136     ///
 137     /// @param Symbol - The symbol to have its n_desc field set.
 138     /// @param DescValue - The value to set into the n_desc field.
 139     virtual void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) = 0;
 140
 141     /// BeginCOFFSymbolDef - Start emitting COFF symbol definition
 142     ///
 143     /// @param Symbol - The symbol to have its External & Type fields set.
 144     virtual void BeginCOFFSymbolDef(const MCSymbol *Symbol) = 0;
 145
 146     /// EmitCOFFSymbolStorageClass - Emit the storage class of the symbol.
 147     ///
 148     /// @param StorageClass - The storage class the symbol should have.
 149     virtual void EmitCOFFSymbolStorageClass(int StorageClass) = 0;
 150
 151     /// EmitCOFFSymbolType - Emit the type of the symbol.
 152     ///
 153     /// @param Type - A COFF type identifier (see COFF::SymbolType in X86COFF.h)
 154     virtual void EmitCOFFSymbolType(int Type) = 0;
 155
 156     /// EndCOFFSymbolDef - Marks the end of the symbol definition.
 157     virtual void EndCOFFSymbolDef() = 0;
 158
 159     /// EmitELFSize - Emit an ELF .size directive.
 160     ///
 161     /// This corresponds to an assembler statement such as:
 162     ///  .size symbol, expression
 163     ///
 164     virtual void EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) = 0;
 165
 166     /// EmitCommonSymbol - Emit a common symbol.
 167     ///
 168     /// @param Symbol - The common symbol to emit.
 169     /// @param Size - The size of the common symbol.
 170     /// @param ByteAlignment - The alignment of the symbol if
 171     /// non-zero. This must be a power of 2.
 172     virtual void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
 173                                   unsigned ByteAlignment) = 0;
 174
 175     /// EmitLocalCommonSymbol - Emit a local common (.lcomm) symbol.
 176     ///
 177     /// @param Symbol - The common symbol to emit.
 178     /// @param Size - The size of the common symbol.
 179     virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size) = 0;
 180
 181     /// EmitZerofill - Emit the zerofill section and an optional symbol.
 182     ///
 183     /// @param Section - The zerofill section to create and or to put the symbol
 184     /// @param Symbol - The zerofill symbol to emit, if non-NULL.
 185     /// @param Size - The size of the zerofill symbol.
 186     /// @param ByteAlignment - The alignment of the zerofill symbol if
 187     /// non-zero. This must be a power of 2 on some targets.
 188     virtual void EmitZerofill(const MCSection *Section, MCSymbol *Symbol = 0,
 189                               unsigned Size = 0,unsigned ByteAlignment = 0) = 0;
 190
 191     /// EmitTBSSSymbol - Emit a thread local bss (.tbss) symbol.
 192     ///
 193     /// @param Section - The thread local common section.
 194     /// @param Symbol - The thread local common symbol to emit.
 195     /// @param Size - The size of the symbol.
 196     /// @param ByteAlignment - The alignment of the thread local common symbol
 197     /// if non-zero.  This must be a power of 2 on some targets.
 198     virtual void EmitTBSSSymbol(const MCSection *Section, MCSymbol *Symbol,
 199                                 uint64_t Size, unsigned ByteAlignment = 0) = 0;
 200     /// @}
 201     /// @name Generating Data
 202     /// @{
 203
 204     /// EmitBytes - Emit the bytes in \arg Data into the output.
 205     ///
 206     /// This is used to implement assembler directives such as .byte, .ascii,
 207     /// etc.
 208     virtual void EmitBytes(StringRef Data, unsigned AddrSpace) = 0;
 209
 210     /// EmitValue - Emit the expression @p Value into the output as a native
 211     /// integer of the given @p Size bytes.
 212     ///
 213     /// This is used to implement assembler directives such as .word, .quad,
 214     /// etc.
 215     ///
 216     /// @param Value - The value to emit.
 217     /// @param Size - The size of the integer (in bytes) to emit. This must
 218     /// match a native machine width.
 219     virtual void EmitValue(const MCExpr *Value, unsigned Size,
 220                            unsigned AddrSpace) = 0;
 221
 222     /// EmitIntValue - Special case of EmitValue that avoids the client having
 223     /// to pass in a MCExpr for constant integers.
 224     virtual void EmitIntValue(uint64_t Value, unsigned Size,unsigned AddrSpace);
 225
 226     /// EmitSymbolValue - Special case of EmitValue that avoids the client
 227     /// having to pass in a MCExpr for MCSymbols.
 228     virtual void EmitSymbolValue(const MCSymbol *Sym, unsigned Size,
 229                                  unsigned AddrSpace);
 230
 231     /// EmitGPRel32Value - Emit the expression @p Value into the output as a
 232     /// gprel32 (32-bit GP relative) value.
 233     ///
 234     /// This is used to implement assembler directives such as .gprel32 on
 235     /// targets that support them.
 236     virtual void EmitGPRel32Value(const MCExpr *Value) = 0;
 237
 238     /// EmitFill - Emit NumBytes bytes worth of the value specified by
 239     /// FillValue.  This implements directives such as '.space'.
 240     virtual void EmitFill(uint64_t NumBytes, uint8_t FillValue,
 241                           unsigned AddrSpace);
 242
 243     /// EmitZeros - Emit NumBytes worth of zeros.  This is a convenience
 244     /// function that just wraps EmitFill.
 245     void EmitZeros(uint64_t NumBytes, unsigned AddrSpace) {
 246       EmitFill(NumBytes, 0, AddrSpace);
 247     }
 248
 249
 250     /// EmitValueToAlignment - Emit some number of copies of @p Value until
 251     /// the byte alignment @p ByteAlignment is reached.
 252     ///
 253     /// If the number of bytes need to emit for the alignment is not a multiple
 254     /// of @p ValueSize, then the contents of the emitted fill bytes is
 255     /// undefined.
 256     ///
 257     /// This used to implement the .align assembler directive.
 258     ///
 259     /// @param ByteAlignment - The alignment to reach. This must be a power of
 260     /// two on some targets.
 261     /// @param Value - The value to use when filling bytes.
 262     /// @param ValueSize - The size of the integer (in bytes) to emit for
 263     /// @p Value. This must match a native machine width.
 264     /// @param MaxBytesToEmit - The maximum numbers of bytes to emit, or 0. If
 265     /// the alignment cannot be reached in this many bytes, no bytes are
 266     /// emitted.
 267     virtual void EmitValueToAlignment(unsigned ByteAlignment, int64_t Value = 0,
 268                                       unsigned ValueSize = 1,
 269                                       unsigned MaxBytesToEmit = 0) = 0;
 270
 271     /// EmitCodeAlignment - Emit nops until the byte alignment @p ByteAlignment
 272     /// is reached.
 273     ///
 274     /// This used to align code where the alignment bytes may be executed.  This
 275     /// can emit different bytes for different sizes to optimize execution.
 276     ///
 277     /// @param ByteAlignment - The alignment to reach. This must be a power of
 278     /// two on some targets.
 279     /// @param MaxBytesToEmit - The maximum numbers of bytes to emit, or 0. If
 280     /// the alignment cannot be reached in this many bytes, no bytes are
 281     /// emitted.
 282     virtual void EmitCodeAlignment(unsigned ByteAlignment,
 283                                    unsigned MaxBytesToEmit = 0) = 0;
 284
 285     /// EmitValueToOffset - Emit some number of copies of @p Value until the
 286     /// byte offset @p Offset is reached.
 287     ///
 288     /// This is used to implement assembler directives such as .org.
 289     ///
 290     /// @param Offset - The offset to reach. This may be an expression, but the
 291     /// expression must be associated with the current section.
 292     /// @param Value - The value to use when filling bytes.
 293     virtual void EmitValueToOffset(const MCExpr *Offset,
 294                                    unsigned char Value = 0) = 0;
 295
 296     /// @}
 297
 298     /// EmitFileDirective - Switch to a new logical file.  This is used to
 299     /// implement the '.file "foo.c"' assembler directive.
 300     virtual void EmitFileDirective(StringRef Filename) = 0;
 301
 302     /// EmitDwarfFileDirective - Associate a filename with a specified logical
 303     /// file number.  This implements the DWARF2 '.file 4 "foo.c"' assembler
 304     /// directive.
 305     virtual void EmitDwarfFileDirective(unsigned FileNo,StringRef Filename) = 0;
 306
 307     /// EmitInstruction - Emit the given @p Instruction into the current
 308     /// section.
 309     virtual void EmitInstruction(const MCInst &Inst) = 0;
 310
 311     /// EmitRawText - If this file is backed by a assembly streamer, this dumps
 312     /// the specified string in the output .s file.  This capability is
 313     /// indicated by the hasRawTextSupport() predicate.  By default this aborts.
 314     virtual void EmitRawText(StringRef String);
 315     void EmitRawText(const Twine &String);
 316
 317     /// Finish - Finish emission of machine code.
 318     virtual void Finish() = 0;
 319   };
 320
 321   /// createNullStreamer - Create a dummy machine code streamer, which does
 322   /// nothing. This is useful for timing the assembler front end.
 323   MCStreamer *createNullStreamer(MCContext &Ctx);
 324
 325   /// createAsmStreamer - Create a machine code streamer which will print out
 326   /// assembly for the native target, suitable for compiling with a native
 327   /// assembler.
 328   ///
 329   /// \param InstPrint - If given, the instruction printer to use. If not given
 330   /// the MCInst representation will be printed.  This method takes ownership of
 331   /// InstPrint.
 332   ///
 333   /// \param CE - If given, a code emitter to use to show the instruction
 334   /// encoding inline with the assembly. This method takes ownership of \arg CE.
 335   ///
 336   /// \param ShowInst - Whether to show the MCInst representation inline with
 337   /// the assembly.
 338   MCStreamer *createAsmStreamer(MCContext &Ctx, formatted_raw_ostream &OS,
 339                                 bool isLittleEndian, bool isVerboseAsm,
 340                                 MCInstPrinter *InstPrint = 0,
 341                                 MCCodeEmitter *CE = 0,
 342                                 bool ShowInst = false);
 343
 344   /// createMachOStreamer - Create a machine code streamer which will generate
 345   /// Mach-O format object files.
 346   ///
 347   /// Takes ownership of \arg TAB and \arg CE.
 348   MCStreamer *createMachOStreamer(MCContext &Ctx, TargetAsmBackend &TAB,
 349                                   raw_ostream &OS, MCCodeEmitter *CE,
 350                                   bool RelaxAll = false);
 351
 352   /// createWinCOFFStreamer - Create a machine code streamer which will
 353   /// generate Microsoft COFF format object files.
 354   ///
 355   /// Takes ownership of \arg TAB and \arg CE.
 356   MCStreamer *createWinCOFFStreamer(MCContext &Ctx,
 357                                     TargetAsmBackend &TAB,
 358                                     MCCodeEmitter &CE, raw_ostream &OS);
 359
 360   /// createLoggingStreamer - Create a machine code streamer which just logs the
 361   /// API calls and then dispatches to another streamer.
 362   ///
 363   /// The new streamer takes ownership of the \arg Child.
 364   MCStreamer *createLoggingStreamer(MCStreamer *Child, raw_ostream &OS);
 365
 366 } // end namespace llvm
 367
 368 #endif