1 //===- MCStreamer.h - High-level Streaming Machine Code Output --*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file declares the MCStreamer class.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_MC_MCSTREAMER_H
15 #define LLVM_MC_MCSTREAMER_H
17 #include "llvm/System/DataTypes.h"
18 #include "llvm/MC/MCDirectives.h"
30 class TargetAsmBackend;
33 class formatted_raw_ostream;
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.
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.
47 MCStreamer(const MCStreamer&); // DO NOT IMPLEMENT
48 MCStreamer &operator=(const MCStreamer&); // DO NOT IMPLEMENT
51 MCStreamer(MCContext &Ctx);
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;
57 /// PrevSection - This is the previous section code is being emitted to, it
58 /// is kept up to date by SwitchSection.
59 const MCSection *PrevSection;
62 virtual ~MCStreamer();
64 MCContext &getContext() const { return Context; }
66 /// @name Assembly File Formatting.
69 /// isVerboseAsm - Return true if this streamer supports verbose assembly
70 /// and if it is enabled.
71 virtual bool isVerboseAsm() const { return false; }
73 /// hasRawTextSupport - Return true if this asm streamer supports emitting
74 /// unformatted text to the .s file with EmitRawText.
75 virtual bool hasRawTextSupport() const { return false; }
77 /// AddComment - Add a comment that can be emitted to the generated .s
78 /// file if applicable as a QoI issue to make the output of the compiler
79 /// more readable. This only affects the MCAsmStreamer, and only when
80 /// verbose assembly output is enabled.
82 /// If the comment includes embedded \n's, they will each get the comment
83 /// prefix as appropriate. The added comment should not end with a \n.
84 virtual void AddComment(const Twine &T) {}
86 /// GetCommentOS - Return a raw_ostream that comments can be written to.
87 /// Unlike AddComment, you are required to terminate comments with \n if you
89 virtual raw_ostream &GetCommentOS();
91 /// AddBlankLine - Emit a blank line to a .s file to pretty it up.
92 virtual void AddBlankLine() {}
96 /// @name Symbol & Section Management
99 /// getCurrentSection - Return the current section that the streamer is
100 /// emitting code to.
101 const MCSection *getCurrentSection() const { return CurSection; }
103 /// getPreviousSection - Return the previous section that the streamer is
104 /// emitting code to.
105 const MCSection *getPreviousSection() const { return PrevSection; }
107 /// SwitchSection - Set the current section where code is being emitted to
108 /// @p Section. This is required to update CurSection.
110 /// This corresponds to assembler directives like .section, .text, etc.
111 virtual void SwitchSection(const MCSection *Section) = 0;
113 /// InitSections - Create the default sections and set the initial one.
114 virtual void InitSections() = 0;
116 /// EmitLabel - Emit a label for @p Symbol into the current section.
118 /// This corresponds to an assembler statement such as:
121 /// @param Symbol - The symbol to emit. A given symbol should only be
122 /// emitted as a label once, and symbols emitted as a label should never be
123 /// used in an assignment.
124 virtual void EmitLabel(MCSymbol *Symbol) = 0;
126 /// EmitAssemblerFlag - Note in the output the specified @p Flag
127 virtual void EmitAssemblerFlag(MCAssemblerFlag Flag) = 0;
129 /// EmitAssignment - Emit an assignment of @p Value to @p Symbol.
131 /// This corresponds to an assembler statement such as:
134 /// The assignment generates no code, but has the side effect of binding the
135 /// value in the current context. For the assembly streamer, this prints the
136 /// binding into the .s file.
138 /// @param Symbol - The symbol being assigned to.
139 /// @param Value - The value for the symbol.
140 virtual void EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) = 0;
142 /// EmitWeakReference - Emit an weak reference from @p Alias to @p Symbol.
144 /// This corresponds to an assembler statement such as:
145 /// .weakref alias, symbol
147 /// @param Alias - The alias that is being created.
148 /// @param Symbol - The symbol being aliased.
149 virtual void EmitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol) = 0;
151 /// EmitSymbolAttribute - Add the given @p Attribute to @p Symbol.
152 virtual void EmitSymbolAttribute(MCSymbol *Symbol,
153 MCSymbolAttr Attribute) = 0;
155 /// EmitSymbolDesc - Set the @p DescValue for the @p Symbol.
157 /// @param Symbol - The symbol to have its n_desc field set.
158 /// @param DescValue - The value to set into the n_desc field.
159 virtual void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) = 0;
161 /// BeginCOFFSymbolDef - Start emitting COFF symbol definition
163 /// @param Symbol - The symbol to have its External & Type fields set.
164 virtual void BeginCOFFSymbolDef(const MCSymbol *Symbol) = 0;
166 /// EmitCOFFSymbolStorageClass - Emit the storage class of the symbol.
168 /// @param StorageClass - The storage class the symbol should have.
169 virtual void EmitCOFFSymbolStorageClass(int StorageClass) = 0;
171 /// EmitCOFFSymbolType - Emit the type of the symbol.
173 /// @param Type - A COFF type identifier (see COFF::SymbolType in X86COFF.h)
174 virtual void EmitCOFFSymbolType(int Type) = 0;
176 /// EndCOFFSymbolDef - Marks the end of the symbol definition.
177 virtual void EndCOFFSymbolDef() = 0;
179 /// EmitELFSize - Emit an ELF .size directive.
181 /// This corresponds to an assembler statement such as:
182 /// .size symbol, expression
184 virtual void EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) = 0;
186 /// EmitCommonSymbol - Emit a common symbol.
188 /// @param Symbol - The common symbol to emit.
189 /// @param Size - The size of the common symbol.
190 /// @param ByteAlignment - The alignment of the symbol if
191 /// non-zero. This must be a power of 2.
192 virtual void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
193 unsigned ByteAlignment) = 0;
195 /// EmitLocalCommonSymbol - Emit a local common (.lcomm) symbol.
197 /// @param Symbol - The common symbol to emit.
198 /// @param Size - The size of the common symbol.
199 virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size) = 0;
201 /// EmitZerofill - Emit the zerofill section and an optional symbol.
203 /// @param Section - The zerofill section to create and or to put the symbol
204 /// @param Symbol - The zerofill symbol to emit, if non-NULL.
205 /// @param Size - The size of the zerofill symbol.
206 /// @param ByteAlignment - The alignment of the zerofill symbol if
207 /// non-zero. This must be a power of 2 on some targets.
208 virtual void EmitZerofill(const MCSection *Section, MCSymbol *Symbol = 0,
209 unsigned Size = 0,unsigned ByteAlignment = 0) = 0;
211 /// EmitTBSSSymbol - Emit a thread local bss (.tbss) symbol.
213 /// @param Section - The thread local common section.
214 /// @param Symbol - The thread local common symbol to emit.
215 /// @param Size - The size of the symbol.
216 /// @param ByteAlignment - The alignment of the thread local common symbol
217 /// if non-zero. This must be a power of 2 on some targets.
218 virtual void EmitTBSSSymbol(const MCSection *Section, MCSymbol *Symbol,
219 uint64_t Size, unsigned ByteAlignment = 0) = 0;
221 /// @name Generating Data
224 /// EmitBytes - Emit the bytes in \arg Data into the output.
226 /// This is used to implement assembler directives such as .byte, .ascii,
228 virtual void EmitBytes(StringRef Data, unsigned AddrSpace) = 0;
230 /// EmitValue - Emit the expression @p Value into the output as a native
231 /// integer of the given @p Size bytes.
233 /// This is used to implement assembler directives such as .word, .quad,
236 /// @param Value - The value to emit.
237 /// @param Size - The size of the integer (in bytes) to emit. This must
238 /// match a native machine width.
239 virtual void EmitValue(const MCExpr *Value, unsigned Size,
240 unsigned AddrSpace = 0) = 0;
242 /// EmitIntValue - Special case of EmitValue that avoids the client having
243 /// to pass in a MCExpr for constant integers.
244 virtual void EmitIntValue(uint64_t Value, unsigned Size,
245 unsigned AddrSpace = 0);
248 virtual void EmitULEB128Value(const MCExpr *Value,
249 unsigned AddrSpace = 0) = 0;
251 virtual void EmitSLEB128Value(const MCExpr *Value,
252 unsigned AddrSpace = 0) = 0;
254 /// EmitULEB128Value - Special case of EmitULEB128Value that avoids the
255 /// client having to pass in a MCExpr for constant integers.
256 virtual void EmitULEB128IntValue(uint64_t Value, unsigned AddrSpace = 0);
258 /// EmitSLEB128Value - Special case of EmitSLEB128Value that avoids the
259 /// client having to pass in a MCExpr for constant integers.
260 virtual void EmitSLEB128IntValue(int64_t Value, unsigned AddrSpace = 0);
262 /// EmitSymbolValue - Special case of EmitValue that avoids the client
263 /// having to pass in a MCExpr for MCSymbols.
264 virtual void EmitSymbolValue(const MCSymbol *Sym, unsigned Size,
265 unsigned AddrSpace = 0);
267 /// EmitGPRel32Value - Emit the expression @p Value into the output as a
268 /// gprel32 (32-bit GP relative) value.
270 /// This is used to implement assembler directives such as .gprel32 on
271 /// targets that support them.
272 virtual void EmitGPRel32Value(const MCExpr *Value) = 0;
274 /// EmitFill - Emit NumBytes bytes worth of the value specified by
275 /// FillValue. This implements directives such as '.space'.
276 virtual void EmitFill(uint64_t NumBytes, uint8_t FillValue,
279 /// EmitZeros - Emit NumBytes worth of zeros. This is a convenience
280 /// function that just wraps EmitFill.
281 void EmitZeros(uint64_t NumBytes, unsigned AddrSpace) {
282 EmitFill(NumBytes, 0, AddrSpace);
286 /// EmitValueToAlignment - Emit some number of copies of @p Value until
287 /// the byte alignment @p ByteAlignment is reached.
289 /// If the number of bytes need to emit for the alignment is not a multiple
290 /// of @p ValueSize, then the contents of the emitted fill bytes is
293 /// This used to implement the .align assembler directive.
295 /// @param ByteAlignment - The alignment to reach. This must be a power of
296 /// two on some targets.
297 /// @param Value - The value to use when filling bytes.
298 /// @param ValueSize - The size of the integer (in bytes) to emit for
299 /// @p Value. This must match a native machine width.
300 /// @param MaxBytesToEmit - The maximum numbers of bytes to emit, or 0. If
301 /// the alignment cannot be reached in this many bytes, no bytes are
303 virtual void EmitValueToAlignment(unsigned ByteAlignment, int64_t Value = 0,
304 unsigned ValueSize = 1,
305 unsigned MaxBytesToEmit = 0) = 0;
307 /// EmitCodeAlignment - Emit nops until the byte alignment @p ByteAlignment
310 /// This used to align code where the alignment bytes may be executed. This
311 /// can emit different bytes for different sizes to optimize execution.
313 /// @param ByteAlignment - The alignment to reach. This must be a power of
314 /// two on some targets.
315 /// @param MaxBytesToEmit - The maximum numbers of bytes to emit, or 0. If
316 /// the alignment cannot be reached in this many bytes, no bytes are
318 virtual void EmitCodeAlignment(unsigned ByteAlignment,
319 unsigned MaxBytesToEmit = 0) = 0;
321 /// EmitValueToOffset - Emit some number of copies of @p Value until the
322 /// byte offset @p Offset is reached.
324 /// This is used to implement assembler directives such as .org.
326 /// @param Offset - The offset to reach. This may be an expression, but the
327 /// expression must be associated with the current section.
328 /// @param Value - The value to use when filling bytes.
329 virtual void EmitValueToOffset(const MCExpr *Offset,
330 unsigned char Value = 0) = 0;
334 /// EmitFileDirective - Switch to a new logical file. This is used to
335 /// implement the '.file "foo.c"' assembler directive.
336 virtual void EmitFileDirective(StringRef Filename) = 0;
338 /// EmitDwarfFileDirective - Associate a filename with a specified logical
339 /// file number. This implements the DWARF2 '.file 4 "foo.c"' assembler
341 virtual void EmitDwarfFileDirective(unsigned FileNo,StringRef Filename) = 0;
343 /// EmitInstruction - Emit the given @p Instruction into the current
345 virtual void EmitInstruction(const MCInst &Inst) = 0;
347 /// EmitRawText - If this file is backed by a assembly streamer, this dumps
348 /// the specified string in the output .s file. This capability is
349 /// indicated by the hasRawTextSupport() predicate. By default this aborts.
350 virtual void EmitRawText(StringRef String);
351 void EmitRawText(const Twine &String);
353 /// Finish - Finish emission of machine code.
354 virtual void Finish() = 0;
357 /// createNullStreamer - Create a dummy machine code streamer, which does
358 /// nothing. This is useful for timing the assembler front end.
359 MCStreamer *createNullStreamer(MCContext &Ctx);
361 /// createAsmStreamer - Create a machine code streamer which will print out
362 /// assembly for the native target, suitable for compiling with a native
365 /// \param InstPrint - If given, the instruction printer to use. If not given
366 /// the MCInst representation will be printed. This method takes ownership of
369 /// \param CE - If given, a code emitter to use to show the instruction
370 /// encoding inline with the assembly. This method takes ownership of \arg CE.
372 /// \param ShowInst - Whether to show the MCInst representation inline with
374 MCStreamer *createAsmStreamer(MCContext &Ctx, formatted_raw_ostream &OS,
375 bool isLittleEndian, bool isVerboseAsm,
376 MCInstPrinter *InstPrint = 0,
377 MCCodeEmitter *CE = 0,
378 bool ShowInst = false);
380 /// createMachOStreamer - Create a machine code streamer which will generate
381 /// Mach-O format object files.
383 /// Takes ownership of \arg TAB and \arg CE.
384 MCStreamer *createMachOStreamer(MCContext &Ctx, TargetAsmBackend &TAB,
385 raw_ostream &OS, MCCodeEmitter *CE,
386 bool RelaxAll = false);
388 /// createWinCOFFStreamer - Create a machine code streamer which will
389 /// generate Microsoft COFF format object files.
391 /// Takes ownership of \arg TAB and \arg CE.
392 MCStreamer *createWinCOFFStreamer(MCContext &Ctx,
393 TargetAsmBackend &TAB,
394 MCCodeEmitter &CE, raw_ostream &OS,
395 bool RelaxAll = false);
397 /// createELFStreamer - Create a machine code streamer which will generate
398 /// ELF format object files.
399 MCStreamer *createELFStreamer(MCContext &Ctx, TargetAsmBackend &TAB,
400 raw_ostream &OS, MCCodeEmitter *CE,
401 bool RelaxAll = false);
403 /// createLoggingStreamer - Create a machine code streamer which just logs the
404 /// API calls and then dispatches to another streamer.
406 /// The new streamer takes ownership of the \arg Child.
407 MCStreamer *createLoggingStreamer(MCStreamer *Child, raw_ostream &OS);
409 } // end namespace llvm