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/MCLinkerOptimizationHint.h"
23#include "llvm/MC/MCWin64EH.h"
24#include "llvm/Support/DataTypes.h"
25#include <string>
26
27namespace llvm {
28class MCAsmBackend;
29class MCCodeEmitter;
30class MCContext;
31class MCExpr;
32class MCInst;
33class MCInstPrinter;
34class MCSection;
35class MCStreamer;
36class MCSymbol;
37class MCSymbolRefExpr;
38class MCSubtargetInfo;
39class StringRef;
40class Twine;
41class raw_ostream;
42class formatted_raw_ostream;
43class AssemblerConstantPools;
44
45typedef std::pair<const MCSection *, const MCExpr *> MCSectionSubPair;
46
47/// Target specific streamer interface. This is used so that targets can
48/// implement support for target specific assembly directives.
49///
50/// If target foo wants to use this, it should implement 3 classes:
51/// * FooTargetStreamer : public MCTargetStreamer
52/// * FooTargetAsmSreamer : public FooTargetStreamer
53/// * FooTargetELFStreamer : public FooTargetStreamer
54///
55/// FooTargetStreamer should have a pure virtual method for each directive. For
56/// example, for a ".bar symbol_name" directive, it should have
57/// virtual emitBar(const MCSymbol &Symbol) = 0;
58///
59/// The FooTargetAsmSreamer and FooTargetELFStreamer classes implement the
60/// method. The assembly streamer just prints ".bar symbol_name". The object
61/// streamer does whatever is needed to implement .bar in the object file.
62///
63/// In the assembly printer and parser the target streamer can be used by
64/// calling getTargetStreamer and casting it to FooTargetStreamer:
65///
66/// MCTargetStreamer &TS = OutStreamer.getTargetStreamer();
67/// FooTargetStreamer &ATS = static_cast<FooTargetStreamer &>(TS);
68///
69/// The base classes FooTargetAsmSreamer and FooTargetELFStreamer should *never*
70/// be treated differently. Callers should always talk to a FooTargetStreamer.
71class MCTargetStreamer {
72protected:
73  MCStreamer &Streamer;
74
75public:
76  MCTargetStreamer(MCStreamer &S);
77  virtual ~MCTargetStreamer();
78
79  const MCStreamer &getStreamer() { return Streamer; }
80
81  // Allow a target to add behavior to the EmitLabel of MCStreamer.
82  virtual void emitLabel(MCSymbol *Symbol);
83  // Allow a target to add behavior to the emitAssignment of MCStreamer.
84  virtual void emitAssignment(MCSymbol *Symbol, const MCExpr *Value);
85
86  virtual void finish();
87};
88
89class AArch64TargetStreamer : public MCTargetStreamer {
90public:
91  AArch64TargetStreamer(MCStreamer &S);
92  ~AArch64TargetStreamer();
93
94
95  void finish() override;
96
97  /// Callback used to implement the ldr= pseudo.
98  /// Add a new entry to the constant pool for the current section and return an
99  /// MCExpr that can be used to refer to the constant pool location.
100  const MCExpr *addConstantPoolEntry(const MCExpr *);
101
102  /// Callback used to implemnt the .ltorg directive.
103  /// Emit contents of constant pool for the current section.
104  void emitCurrentConstantPool();
105
106private:
107  std::unique_ptr<AssemblerConstantPools> ConstantPools;
108};
109
110// FIXME: declared here because it is used from
111// lib/CodeGen/AsmPrinter/ARMException.cpp.
112class ARMTargetStreamer : public MCTargetStreamer {
113public:
114  ARMTargetStreamer(MCStreamer &S);
115  ~ARMTargetStreamer();
116
117  virtual void emitFnStart();
118  virtual void emitFnEnd();
119  virtual void emitCantUnwind();
120  virtual void emitPersonality(const MCSymbol *Personality);
121  virtual void emitPersonalityIndex(unsigned Index);
122  virtual void emitHandlerData();
123  virtual void emitSetFP(unsigned FpReg, unsigned SpReg,
124                         int64_t Offset = 0);
125  virtual void emitMovSP(unsigned Reg, int64_t Offset = 0);
126  virtual void emitPad(int64_t Offset);
127  virtual void emitRegSave(const SmallVectorImpl<unsigned> &RegList,
128                           bool isVector);
129  virtual void emitUnwindRaw(int64_t StackOffset,
130                             const SmallVectorImpl<uint8_t> &Opcodes);
131
132  virtual void switchVendor(StringRef Vendor);
133  virtual void emitAttribute(unsigned Attribute, unsigned Value);
134  virtual void emitTextAttribute(unsigned Attribute, StringRef String);
135  virtual void emitIntTextAttribute(unsigned Attribute, unsigned IntValue,
136                                    StringRef StringValue = "");
137  virtual void emitFPU(unsigned FPU);
138  virtual void emitArch(unsigned Arch);
139  virtual void emitObjectArch(unsigned Arch);
140  virtual void finishAttributeSection();
141  virtual void emitInst(uint32_t Inst, char Suffix = '\0');
142
143  virtual void AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *SRE);
144
145  virtual void emitThumbSet(MCSymbol *Symbol, const MCExpr *Value);
146
147  void finish() override;
148
149  /// Callback used to implement the ldr= pseudo.
150  /// Add a new entry to the constant pool for the current section and return an
151  /// MCExpr that can be used to refer to the constant pool location.
152  const MCExpr *addConstantPoolEntry(const MCExpr *);
153
154  /// Callback used to implemnt the .ltorg directive.
155  /// Emit contents of constant pool for the current section.
156  void emitCurrentConstantPool();
157
158private:
159  std::unique_ptr<AssemblerConstantPools> ConstantPools;
160};
161
162/// MCStreamer - Streaming machine code generation interface.  This interface
163/// is intended to provide a programatic interface that is very similar to the
164/// level that an assembler .s file provides.  It has callbacks to emit bytes,
165/// handle directives, etc.  The implementation of this interface retains
166/// state to know what the current section is etc.
167///
168/// There are multiple implementations of this interface: one for writing out
169/// a .s file, and implementations that write out .o files of various formats.
170///
171class MCStreamer {
172  MCContext &Context;
173  std::unique_ptr<MCTargetStreamer> TargetStreamer;
174
175  MCStreamer(const MCStreamer &) LLVM_DELETED_FUNCTION;
176  MCStreamer &operator=(const MCStreamer &) LLVM_DELETED_FUNCTION;
177
178  std::vector<MCDwarfFrameInfo> FrameInfos;
179  MCDwarfFrameInfo *getCurrentFrameInfo();
180  MCSymbol *EmitCFICommon();
181  void EnsureValidFrame();
182
183  std::vector<MCWin64EHUnwindInfo *> W64UnwindInfos;
184  MCWin64EHUnwindInfo *CurrentW64UnwindInfo;
185  void setCurrentW64UnwindInfo(MCWin64EHUnwindInfo *Frame);
186  void EnsureValidW64UnwindInfo();
187
188  // SymbolOrdering - Tracks an index to represent the order
189  // a symbol was emitted in. Zero means we did not emit that symbol.
190  DenseMap<const MCSymbol *, unsigned> SymbolOrdering;
191
192  /// SectionStack - This is stack of current and previous section
193  /// values saved by PushSection.
194  SmallVector<std::pair<MCSectionSubPair, MCSectionSubPair>, 4> SectionStack;
195
196protected:
197  MCStreamer(MCContext &Ctx);
198
199  const MCExpr *BuildSymbolDiff(MCContext &Context, const MCSymbol *A,
200                                const MCSymbol *B);
201
202  const MCExpr *ForceExpAbs(const MCExpr *Expr);
203
204  virtual void EmitCFIStartProcImpl(MCDwarfFrameInfo &Frame);
205  virtual void EmitCFIEndProcImpl(MCDwarfFrameInfo &CurFrame);
206
207  MCWin64EHUnwindInfo *getCurrentW64UnwindInfo() {
208    return CurrentW64UnwindInfo;
209  }
210  void EmitW64Tables();
211
212  virtual void EmitRawTextImpl(StringRef String);
213
214public:
215  virtual ~MCStreamer();
216
217  void visitUsedExpr(const MCExpr &Expr);
218  virtual void visitUsedSymbol(const MCSymbol &Sym);
219
220  void setTargetStreamer(MCTargetStreamer *TS) {
221    TargetStreamer.reset(TS);
222  }
223
224  /// State management
225  ///
226  virtual void reset();
227
228  MCContext &getContext() const { return Context; }
229
230  MCTargetStreamer *getTargetStreamer() {
231    return TargetStreamer.get();
232  }
233
234  unsigned getNumFrameInfos() { return FrameInfos.size(); }
235
236  const MCDwarfFrameInfo &getFrameInfo(unsigned i) { return FrameInfos[i]; }
237
238  ArrayRef<MCDwarfFrameInfo> getFrameInfos() const { return FrameInfos; }
239
240  unsigned getNumW64UnwindInfos() { return W64UnwindInfos.size(); }
241
242  MCWin64EHUnwindInfo &getW64UnwindInfo(unsigned i) {
243    return *W64UnwindInfos[i];
244  }
245
246  ArrayRef<MCWin64EHUnwindInfo *> getW64UnwindInfos() const {
247    return W64UnwindInfos;
248  }
249
250  void generateCompactUnwindEncodings(MCAsmBackend *MAB);
251
252  /// @name Assembly File Formatting.
253  /// @{
254
255  /// isVerboseAsm - Return true if this streamer supports verbose assembly
256  /// and if it is enabled.
257  virtual bool isVerboseAsm() const { return false; }
258
259  /// hasRawTextSupport - Return true if this asm streamer supports emitting
260  /// unformatted text to the .s file with EmitRawText.
261  virtual bool hasRawTextSupport() const { return false; }
262
263  /// Is the integrated assembler required for this streamer to function
264  /// correctly?
265  virtual bool isIntegratedAssemblerRequired() const { return false; }
266
267  /// AddComment - Add a comment that can be emitted to the generated .s
268  /// file if applicable as a QoI issue to make the output of the compiler
269  /// more readable.  This only affects the MCAsmStreamer, and only when
270  /// verbose assembly output is enabled.
271  ///
272  /// If the comment includes embedded \n's, they will each get the comment
273  /// prefix as appropriate.  The added comment should not end with a \n.
274  virtual void AddComment(const Twine &T) {}
275
276  /// GetCommentOS - Return a raw_ostream that comments can be written to.
277  /// Unlike AddComment, you are required to terminate comments with \n if you
278  /// use this method.
279  virtual raw_ostream &GetCommentOS();
280
281  /// Print T and prefix it with the comment string (normally #) and optionally
282  /// a tab. This prints the comment immediately, not at the end of the
283  /// current line. It is basically a safe version of EmitRawText: since it
284  /// only prints comments, the object streamer ignores it instead of asserting.
285  virtual void emitRawComment(const Twine &T, bool TabPrefix = true);
286
287  /// AddBlankLine - Emit a blank line to a .s file to pretty it up.
288  virtual void AddBlankLine() {}
289
290  /// @}
291
292  /// @name Symbol & Section Management
293  /// @{
294
295  /// getCurrentSection - Return the current section that the streamer is
296  /// emitting code to.
297  MCSectionSubPair getCurrentSection() const {
298    if (!SectionStack.empty())
299      return SectionStack.back().first;
300    return MCSectionSubPair();
301  }
302
303  /// getPreviousSection - Return the previous section that the streamer is
304  /// emitting code to.
305  MCSectionSubPair getPreviousSection() const {
306    if (!SectionStack.empty())
307      return SectionStack.back().second;
308    return MCSectionSubPair();
309  }
310
311  /// GetSymbolOrder - Returns an index to represent the order
312  /// a symbol was emitted in. (zero if we did not emit that symbol)
313  unsigned GetSymbolOrder(const MCSymbol *Sym) const {
314    return SymbolOrdering.lookup(Sym);
315  }
316
317  /// ChangeSection - Update streamer for a new active section.
318  ///
319  /// This is called by PopSection and SwitchSection, if the current
320  /// section changes.
321  virtual void ChangeSection(const MCSection *, const MCExpr *);
322
323  /// pushSection - Save the current and previous section on the
324  /// section stack.
325  void PushSection() {
326    SectionStack.push_back(
327        std::make_pair(getCurrentSection(), getPreviousSection()));
328  }
329
330  /// popSection - Restore the current and previous section from
331  /// the section stack.  Calls ChangeSection as needed.
332  ///
333  /// Returns false if the stack was empty.
334  bool PopSection() {
335    if (SectionStack.size() <= 1)
336      return false;
337    MCSectionSubPair oldSection = SectionStack.pop_back_val().first;
338    MCSectionSubPair curSection = SectionStack.back().first;
339
340    if (oldSection != curSection)
341      ChangeSection(curSection.first, curSection.second);
342    return true;
343  }
344
345  bool SubSection(const MCExpr *Subsection) {
346    if (SectionStack.empty())
347      return false;
348
349    SwitchSection(SectionStack.back().first.first, Subsection);
350    return true;
351  }
352
353  /// SwitchSection - Set the current section where code is being emitted to
354  /// @p Section.  This is required to update CurSection.
355  ///
356  /// This corresponds to assembler directives like .section, .text, etc.
357  void SwitchSection(const MCSection *Section,
358                     const MCExpr *Subsection = nullptr) {
359    assert(Section && "Cannot switch to a null section!");
360    MCSectionSubPair curSection = SectionStack.back().first;
361    SectionStack.back().second = curSection;
362    if (MCSectionSubPair(Section, Subsection) != curSection) {
363      SectionStack.back().first = MCSectionSubPair(Section, Subsection);
364      ChangeSection(Section, Subsection);
365    }
366  }
367
368  /// SwitchSectionNoChange - Set the current section where code is being
369  /// emitted to @p Section.  This is required to update CurSection. This
370  /// version does not call ChangeSection.
371  void SwitchSectionNoChange(const MCSection *Section,
372                             const MCExpr *Subsection = nullptr) {
373    assert(Section && "Cannot switch to a null section!");
374    MCSectionSubPair curSection = SectionStack.back().first;
375    SectionStack.back().second = curSection;
376    if (MCSectionSubPair(Section, Subsection) != curSection)
377      SectionStack.back().first = MCSectionSubPair(Section, Subsection);
378  }
379
380  /// Create the default sections and set the initial one.
381  virtual void InitSections();
382
383  /// AssignSection - Sets the symbol's section.
384  ///
385  /// Each emitted symbol will be tracked in the ordering table,
386  /// so we can sort on them later.
387  void AssignSection(MCSymbol *Symbol, const MCSection *Section);
388
389  /// EmitLabel - Emit a label for @p Symbol into the current section.
390  ///
391  /// This corresponds to an assembler statement such as:
392  ///   foo:
393  ///
394  /// @param Symbol - The symbol to emit. A given symbol should only be
395  /// emitted as a label once, and symbols emitted as a label should never be
396  /// used in an assignment.
397  // FIXME: These emission are non-const because we mutate the symbol to
398  // add the section we're emitting it to later.
399  virtual void EmitLabel(MCSymbol *Symbol);
400
401  virtual void EmitEHSymAttributes(const MCSymbol *Symbol, MCSymbol *EHSymbol);
402
403  /// EmitAssemblerFlag - Note in the output the specified @p Flag.
404  virtual void EmitAssemblerFlag(MCAssemblerFlag Flag);
405
406  /// EmitLinkerOptions - Emit the given list @p Options of strings as linker
407  /// options into the output.
408  virtual void EmitLinkerOptions(ArrayRef<std::string> Kind) {}
409
410  /// EmitDataRegion - Note in the output the specified region @p Kind.
411  virtual void EmitDataRegion(MCDataRegionType Kind) {}
412
413  /// EmitVersionMin - Specify the MachO minimum deployment target version.
414  virtual void EmitVersionMin(MCVersionMinType, unsigned Major, unsigned Minor,
415                              unsigned Update) {}
416
417  /// EmitThumbFunc - Note in the output that the specified @p Func is
418  /// a Thumb mode function (ARM target only).
419  virtual void EmitThumbFunc(MCSymbol *Func);
420
421  /// EmitAssignment - Emit an assignment of @p Value to @p Symbol.
422  ///
423  /// This corresponds to an assembler statement such as:
424  ///  symbol = value
425  ///
426  /// The assignment generates no code, but has the side effect of binding the
427  /// value in the current context. For the assembly streamer, this prints the
428  /// binding into the .s file.
429  ///
430  /// @param Symbol - The symbol being assigned to.
431  /// @param Value - The value for the symbol.
432  virtual void EmitAssignment(MCSymbol *Symbol, const MCExpr *Value);
433
434  /// EmitWeakReference - Emit an weak reference from @p Alias to @p Symbol.
435  ///
436  /// This corresponds to an assembler statement such as:
437  ///  .weakref alias, symbol
438  ///
439  /// @param Alias - The alias that is being created.
440  /// @param Symbol - The symbol being aliased.
441  virtual void EmitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol);
442
443  /// EmitSymbolAttribute - Add the given @p Attribute to @p Symbol.
444  virtual bool EmitSymbolAttribute(MCSymbol *Symbol,
445                                   MCSymbolAttr Attribute) = 0;
446
447  /// EmitSymbolDesc - Set the @p DescValue for the @p Symbol.
448  ///
449  /// @param Symbol - The symbol to have its n_desc field set.
450  /// @param DescValue - The value to set into the n_desc field.
451  virtual void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue);
452
453  /// BeginCOFFSymbolDef - Start emitting COFF symbol definition
454  ///
455  /// @param Symbol - The symbol to have its External & Type fields set.
456  virtual void BeginCOFFSymbolDef(const MCSymbol *Symbol);
457
458  /// EmitCOFFSymbolStorageClass - Emit the storage class of the symbol.
459  ///
460  /// @param StorageClass - The storage class the symbol should have.
461  virtual void EmitCOFFSymbolStorageClass(int StorageClass);
462
463  /// EmitCOFFSymbolType - Emit the type of the symbol.
464  ///
465  /// @param Type - A COFF type identifier (see COFF::SymbolType in X86COFF.h)
466  virtual void EmitCOFFSymbolType(int Type);
467
468  /// EndCOFFSymbolDef - Marks the end of the symbol definition.
469  virtual void EndCOFFSymbolDef();
470
471  /// EmitCOFFSectionIndex - Emits a COFF section index.
472  ///
473  /// @param Symbol - Symbol the section number relocation should point to.
474  virtual void EmitCOFFSectionIndex(MCSymbol const *Symbol);
475
476  /// EmitCOFFSecRel32 - Emits a COFF section relative relocation.
477  ///
478  /// @param Symbol - Symbol the section relative relocation should point to.
479  virtual void EmitCOFFSecRel32(MCSymbol const *Symbol);
480
481  /// EmitELFSize - Emit an ELF .size directive.
482  ///
483  /// This corresponds to an assembler statement such as:
484  ///  .size symbol, expression
485  ///
486  virtual void EmitELFSize(MCSymbol *Symbol, const MCExpr *Value);
487
488  /// \brief Emit a Linker Optimization Hint (LOH) directive.
489  /// \param Args - Arguments of the LOH.
490  virtual void EmitLOHDirective(MCLOHType Kind, const MCLOHArgs &Args) {}
491
492  /// EmitCommonSymbol - Emit a common symbol.
493  ///
494  /// @param Symbol - The common symbol to emit.
495  /// @param Size - The size of the common symbol.
496  /// @param ByteAlignment - The alignment of the symbol if
497  /// non-zero. This must be a power of 2.
498  virtual void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
499                                unsigned ByteAlignment) = 0;
500
501  /// EmitLocalCommonSymbol - Emit a local common (.lcomm) symbol.
502  ///
503  /// @param Symbol - The common symbol to emit.
504  /// @param Size - The size of the common symbol.
505  /// @param ByteAlignment - The alignment of the common symbol in bytes.
506  virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
507                                     unsigned ByteAlignment);
508
509  /// EmitZerofill - Emit the zerofill section and an optional symbol.
510  ///
511  /// @param Section - The zerofill section to create and or to put the symbol
512  /// @param Symbol - The zerofill symbol to emit, if non-NULL.
513  /// @param Size - The size of the zerofill symbol.
514  /// @param ByteAlignment - The alignment of the zerofill symbol if
515  /// non-zero. This must be a power of 2 on some targets.
516  virtual void EmitZerofill(const MCSection *Section,
517                            MCSymbol *Symbol = nullptr, uint64_t Size = 0,
518                            unsigned ByteAlignment = 0) = 0;
519
520  /// EmitTBSSSymbol - Emit a thread local bss (.tbss) symbol.
521  ///
522  /// @param Section - The thread local common section.
523  /// @param Symbol - The thread local common symbol to emit.
524  /// @param Size - The size of the symbol.
525  /// @param ByteAlignment - The alignment of the thread local common symbol
526  /// if non-zero.  This must be a power of 2 on some targets.
527  virtual void EmitTBSSSymbol(const MCSection *Section, MCSymbol *Symbol,
528                              uint64_t Size, unsigned ByteAlignment = 0);
529
530  /// @}
531  /// @name Generating Data
532  /// @{
533
534  /// EmitBytes - Emit the bytes in \p Data into the output.
535  ///
536  /// This is used to implement assembler directives such as .byte, .ascii,
537  /// etc.
538  virtual void EmitBytes(StringRef Data);
539
540  /// EmitValue - Emit the expression @p Value into the output as a native
541  /// integer of the given @p Size bytes.
542  ///
543  /// This is used to implement assembler directives such as .word, .quad,
544  /// etc.
545  ///
546  /// @param Value - The value to emit.
547  /// @param Size - The size of the integer (in bytes) to emit. This must
548  /// match a native machine width.
549  /// @param Loc - The location of the expression for error reporting.
550  virtual void EmitValueImpl(const MCExpr *Value, unsigned Size,
551                             const SMLoc &Loc = SMLoc());
552
553  void EmitValue(const MCExpr *Value, unsigned Size,
554                 const SMLoc &Loc = SMLoc());
555
556  /// EmitIntValue - Special case of EmitValue that avoids the client having
557  /// to pass in a MCExpr for constant integers.
558  virtual void EmitIntValue(uint64_t Value, unsigned Size);
559
560  /// EmitAbsValue - Emit the Value, but try to avoid relocations. On MachO
561  /// this is done by producing
562  /// foo = value
563  /// .long foo
564  void EmitAbsValue(const MCExpr *Value, unsigned Size);
565
566  virtual void EmitULEB128Value(const MCExpr *Value);
567
568  virtual void EmitSLEB128Value(const MCExpr *Value);
569
570  /// EmitULEB128Value - Special case of EmitULEB128Value that avoids the
571  /// client having to pass in a MCExpr for constant integers.
572  void EmitULEB128IntValue(uint64_t Value, unsigned Padding = 0);
573
574  /// EmitSLEB128Value - Special case of EmitSLEB128Value that avoids the
575  /// client having to pass in a MCExpr for constant integers.
576  void EmitSLEB128IntValue(int64_t Value);
577
578  /// EmitSymbolValue - Special case of EmitValue that avoids the client
579  /// having to pass in a MCExpr for MCSymbols.
580  void EmitSymbolValue(const MCSymbol *Sym, unsigned Size);
581
582  /// EmitGPRel64Value - Emit the expression @p Value into the output as a
583  /// gprel64 (64-bit GP relative) value.
584  ///
585  /// This is used to implement assembler directives such as .gpdword on
586  /// targets that support them.
587  virtual void EmitGPRel64Value(const MCExpr *Value);
588
589  /// EmitGPRel32Value - Emit the expression @p Value into the output as a
590  /// gprel32 (32-bit GP relative) value.
591  ///
592  /// This is used to implement assembler directives such as .gprel32 on
593  /// targets that support them.
594  virtual void EmitGPRel32Value(const MCExpr *Value);
595
596  /// EmitFill - Emit NumBytes bytes worth of the value specified by
597  /// FillValue.  This implements directives such as '.space'.
598  virtual void EmitFill(uint64_t NumBytes, uint8_t FillValue);
599
600  /// \brief Emit NumBytes worth of zeros.
601  /// This function properly handles data in virtual sections.
602  virtual void EmitZeros(uint64_t NumBytes);
603
604  /// EmitValueToAlignment - Emit some number of copies of @p Value until
605  /// the byte alignment @p ByteAlignment is reached.
606  ///
607  /// If the number of bytes need to emit for the alignment is not a multiple
608  /// of @p ValueSize, then the contents of the emitted fill bytes is
609  /// undefined.
610  ///
611  /// This used to implement the .align assembler directive.
612  ///
613  /// @param ByteAlignment - The alignment to reach. This must be a power of
614  /// two on some targets.
615  /// @param Value - The value to use when filling bytes.
616  /// @param ValueSize - The size of the integer (in bytes) to emit for
617  /// @p Value. This must match a native machine width.
618  /// @param MaxBytesToEmit - The maximum numbers of bytes to emit, or 0. If
619  /// the alignment cannot be reached in this many bytes, no bytes are
620  /// emitted.
621  virtual void EmitValueToAlignment(unsigned ByteAlignment, int64_t Value = 0,
622                                    unsigned ValueSize = 1,
623                                    unsigned MaxBytesToEmit = 0);
624
625  /// EmitCodeAlignment - Emit nops until the byte alignment @p ByteAlignment
626  /// is reached.
627  ///
628  /// This used to align code where the alignment bytes may be executed.  This
629  /// can emit different bytes for different sizes to optimize execution.
630  ///
631  /// @param ByteAlignment - The alignment to reach. This must be a power of
632  /// two on some targets.
633  /// @param MaxBytesToEmit - The maximum numbers of bytes to emit, or 0. If
634  /// the alignment cannot be reached in this many bytes, no bytes are
635  /// emitted.
636  virtual void EmitCodeAlignment(unsigned ByteAlignment,
637                                 unsigned MaxBytesToEmit = 0);
638
639  /// EmitValueToOffset - Emit some number of copies of @p Value until the
640  /// byte offset @p Offset is reached.
641  ///
642  /// This is used to implement assembler directives such as .org.
643  ///
644  /// @param Offset - The offset to reach. This may be an expression, but the
645  /// expression must be associated with the current section.
646  /// @param Value - The value to use when filling bytes.
647  /// @return false on success, true if the offset was invalid.
648  virtual bool EmitValueToOffset(const MCExpr *Offset,
649                                 unsigned char Value = 0);
650
651  /// @}
652
653  /// EmitFileDirective - Switch to a new logical file.  This is used to
654  /// implement the '.file "foo.c"' assembler directive.
655  virtual void EmitFileDirective(StringRef Filename);
656
657  /// Emit the "identifiers" directive.  This implements the
658  /// '.ident "version foo"' assembler directive.
659  virtual void EmitIdent(StringRef IdentString) {}
660
661  /// EmitDwarfFileDirective - Associate a filename with a specified logical
662  /// file number.  This implements the DWARF2 '.file 4 "foo.c"' assembler
663  /// directive.
664  virtual unsigned EmitDwarfFileDirective(unsigned FileNo, StringRef Directory,
665                                          StringRef Filename,
666                                          unsigned CUID = 0);
667
668  /// EmitDwarfLocDirective - This implements the DWARF2
669  // '.loc fileno lineno ...' assembler directive.
670  virtual void EmitDwarfLocDirective(unsigned FileNo, unsigned Line,
671                                     unsigned Column, unsigned Flags,
672                                     unsigned Isa, unsigned Discriminator,
673                                     StringRef FileName);
674
675  virtual MCSymbol *getDwarfLineTableSymbol(unsigned CUID);
676
677  void EmitDwarfSetLineAddr(int64_t LineDelta, const MCSymbol *Label,
678                            int PointerSize);
679
680  virtual void EmitCompactUnwindEncoding(uint32_t CompactUnwindEncoding);
681  virtual void EmitCFISections(bool EH, bool Debug);
682  void EmitCFIStartProc(bool IsSimple);
683  void EmitCFIEndProc();
684  virtual void EmitCFIDefCfa(int64_t Register, int64_t Offset);
685  virtual void EmitCFIDefCfaOffset(int64_t Offset);
686  virtual void EmitCFIDefCfaRegister(int64_t Register);
687  virtual void EmitCFIOffset(int64_t Register, int64_t Offset);
688  virtual void EmitCFIPersonality(const MCSymbol *Sym, unsigned Encoding);
689  virtual void EmitCFILsda(const MCSymbol *Sym, unsigned Encoding);
690  virtual void EmitCFIRememberState();
691  virtual void EmitCFIRestoreState();
692  virtual void EmitCFISameValue(int64_t Register);
693  virtual void EmitCFIRestore(int64_t Register);
694  virtual void EmitCFIRelOffset(int64_t Register, int64_t Offset);
695  virtual void EmitCFIAdjustCfaOffset(int64_t Adjustment);
696  virtual void EmitCFIEscape(StringRef Values);
697  virtual void EmitCFISignalFrame();
698  virtual void EmitCFIUndefined(int64_t Register);
699  virtual void EmitCFIRegister(int64_t Register1, int64_t Register2);
700  virtual void EmitCFIWindowSave();
701
702  virtual void EmitWinCFIStartProc(const MCSymbol *Symbol);
703  virtual void EmitWinCFIEndProc();
704  virtual void EmitWinCFIStartChained();
705  virtual void EmitWinCFIEndChained();
706  virtual void EmitWinCFIPushReg(unsigned Register);
707  virtual void EmitWinCFISetFrame(unsigned Register, unsigned Offset);
708  virtual void EmitWinCFIAllocStack(unsigned Size);
709  virtual void EmitWinCFISaveReg(unsigned Register, unsigned Offset);
710  virtual void EmitWinCFISaveXMM(unsigned Register, unsigned Offset);
711  virtual void EmitWinCFIPushFrame(bool Code);
712  virtual void EmitWinCFIEndProlog();
713
714  virtual void EmitWinEHHandler(const MCSymbol *Sym, bool Unwind, bool Except);
715  virtual void EmitWinEHHandlerData();
716
717  /// EmitInstruction - Emit the given @p Instruction into the current
718  /// section.
719  virtual void EmitInstruction(const MCInst &Inst, const MCSubtargetInfo &STI);
720
721  /// \brief Set the bundle alignment mode from now on in the section.
722  /// The argument is the power of 2 to which the alignment is set. The
723  /// value 0 means turn the bundle alignment off.
724  virtual void EmitBundleAlignMode(unsigned AlignPow2);
725
726  /// \brief The following instructions are a bundle-locked group.
727  ///
728  /// \param AlignToEnd - If true, the bundle-locked group will be aligned to
729  ///                     the end of a bundle.
730  virtual void EmitBundleLock(bool AlignToEnd);
731
732  /// \brief Ends a bundle-locked group.
733  virtual void EmitBundleUnlock();
734
735  /// EmitRawText - If this file is backed by a assembly streamer, this dumps
736  /// the specified string in the output .s file.  This capability is
737  /// indicated by the hasRawTextSupport() predicate.  By default this aborts.
738  void EmitRawText(const Twine &String);
739
740  /// Flush - Causes any cached state to be written out.
741  virtual void Flush() {}
742
743  /// FinishImpl - Streamer specific finalization.
744  virtual void FinishImpl();
745  /// Finish - Finish emission of machine code.
746  void Finish();
747
748  virtual bool mayHaveInstructions() const { return true; }
749};
750
751/// createNullStreamer - Create a dummy machine code streamer, which does
752/// nothing. This is useful for timing the assembler front end.
753MCStreamer *createNullStreamer(MCContext &Ctx);
754
755/// createAsmStreamer - Create a machine code streamer which will print out
756/// assembly for the native target, suitable for compiling with a native
757/// assembler.
758///
759/// \param InstPrint - If given, the instruction printer to use. If not given
760/// the MCInst representation will be printed.  This method takes ownership of
761/// InstPrint.
762///
763/// \param CE - If given, a code emitter to use to show the instruction
764/// encoding inline with the assembly. This method takes ownership of \p CE.
765///
766/// \param TAB - If given, a target asm backend to use to show the fixup
767/// information in conjunction with encoding information. This method takes
768/// ownership of \p TAB.
769///
770/// \param ShowInst - Whether to show the MCInst representation inline with
771/// the assembly.
772MCStreamer *createAsmStreamer(MCContext &Ctx, formatted_raw_ostream &OS,
773                              bool isVerboseAsm, bool useDwarfDirectory,
774                              MCInstPrinter *InstPrint, MCCodeEmitter *CE,
775                              MCAsmBackend *TAB, bool ShowInst);
776
777/// createMachOStreamer - Create a machine code streamer which will generate
778/// Mach-O format object files.
779///
780/// Takes ownership of \p TAB and \p CE.
781MCStreamer *createMachOStreamer(MCContext &Ctx, MCAsmBackend &TAB,
782                                raw_ostream &OS, MCCodeEmitter *CE,
783                                bool RelaxAll = false,
784                                bool LabelSections = false);
785
786/// createELFStreamer - Create a machine code streamer which will generate
787/// ELF format object files.
788MCStreamer *createELFStreamer(MCContext &Ctx, MCAsmBackend &TAB,
789                              raw_ostream &OS, MCCodeEmitter *CE, bool RelaxAll,
790                              bool NoExecStack);
791
792} // end namespace llvm
793
794#endif
795