aboutsummaryrefslogtreecommitdiffstats
path: root/contrib/libs/llvm14/include/llvm/MC/MCStreamer.h
blob: 02b3fd232e0592e716832ed0c3d9b4a1f163f8ef (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
#pragma once

#ifdef __GNUC__
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wunused-parameter"
#endif

//===- MCStreamer.h - High-level Streaming Machine Code Output --*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file declares the MCStreamer class.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_MC_MCSTREAMER_H
#define LLVM_MC_MCSTREAMER_H

#include "llvm/ADT/APInt.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/ADT/Optional.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/MC/MCDirectives.h"
#include "llvm/MC/MCLinkerOptimizationHint.h"
#include "llvm/MC/MCPseudoProbe.h"
#include "llvm/MC/MCSymbol.h"
#include "llvm/MC/MCWinEH.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/MD5.h"
#include "llvm/Support/SMLoc.h"
#include "llvm/Support/ARMTargetParser.h"
#include "llvm/Support/TargetParser.h"
#include "llvm/Support/VersionTuple.h"
#include <cassert>
#include <cstdint>
#include <memory>
#include <string>
#include <utility>
#include <vector>

namespace llvm {

class AssemblerConstantPools;
class MCAsmBackend;
class MCContext;
struct MCDwarfFrameInfo;
class MCExpr;
class MCInst;
class MCInstPrinter;
class MCRegister;
class MCSection;
class MCStreamer;
class MCSymbolRefExpr;
class MCSubtargetInfo;
class raw_ostream;
class Twine;

namespace codeview {
struct DefRangeRegisterRelHeader;
struct DefRangeSubfieldRegisterHeader;
struct DefRangeRegisterHeader;
struct DefRangeFramePointerRelHeader;
}

using MCSectionSubPair = std::pair<MCSection *, const MCExpr *>;

/// Target specific streamer interface. This is used so that targets can
/// implement support for target specific assembly directives.
///
/// If target foo wants to use this, it should implement 3 classes:
/// * FooTargetStreamer : public MCTargetStreamer
/// * FooTargetAsmStreamer : public FooTargetStreamer
/// * FooTargetELFStreamer : public FooTargetStreamer
///
/// FooTargetStreamer should have a pure virtual method for each directive. For
/// example, for a ".bar symbol_name" directive, it should have
/// virtual emitBar(const MCSymbol &Symbol) = 0;
///
/// The FooTargetAsmStreamer and FooTargetELFStreamer classes implement the
/// method. The assembly streamer just prints ".bar symbol_name". The object
/// streamer does whatever is needed to implement .bar in the object file.
///
/// In the assembly printer and parser the target streamer can be used by
/// calling getTargetStreamer and casting it to FooTargetStreamer:
///
/// MCTargetStreamer &TS = OutStreamer.getTargetStreamer();
/// FooTargetStreamer &ATS = static_cast<FooTargetStreamer &>(TS);
///
/// The base classes FooTargetAsmStreamer and FooTargetELFStreamer should
/// *never* be treated differently. Callers should always talk to a
/// FooTargetStreamer.
class MCTargetStreamer {
protected:
  MCStreamer &Streamer;

public:
  MCTargetStreamer(MCStreamer &S);
  virtual ~MCTargetStreamer();

  MCStreamer &getStreamer() { return Streamer; }

  // Allow a target to add behavior to the EmitLabel of MCStreamer.
  virtual void emitLabel(MCSymbol *Symbol);
  // Allow a target to add behavior to the emitAssignment of MCStreamer.
  virtual void emitAssignment(MCSymbol *Symbol, const MCExpr *Value);

  virtual void prettyPrintAsm(MCInstPrinter &InstPrinter, uint64_t Address,
                              const MCInst &Inst, const MCSubtargetInfo &STI,
                              raw_ostream &OS);

  virtual void emitDwarfFileDirective(StringRef Directive);

  /// Update streamer for a new active section.
  ///
  /// This is called by PopSection and SwitchSection, if the current
  /// section changes.
  virtual void changeSection(const MCSection *CurSection, MCSection *Section,
                             const MCExpr *SubSection, raw_ostream &OS);

  virtual void emitValue(const MCExpr *Value);

  /// Emit the bytes in \p Data into the output.
  ///
  /// This is used to emit bytes in \p Data as sequence of .byte directives.
  virtual void emitRawBytes(StringRef Data);

  virtual void emitConstantPools();

  virtual void finish();
};

// FIXME: declared here because it is used from
// lib/CodeGen/AsmPrinter/ARMException.cpp.
class ARMTargetStreamer : public MCTargetStreamer {
public:
  ARMTargetStreamer(MCStreamer &S);
  ~ARMTargetStreamer() override;

  virtual void emitFnStart();
  virtual void emitFnEnd();
  virtual void emitCantUnwind();
  virtual void emitPersonality(const MCSymbol *Personality);
  virtual void emitPersonalityIndex(unsigned Index);
  virtual void emitHandlerData();
  virtual void emitSetFP(unsigned FpReg, unsigned SpReg,
                         int64_t Offset = 0);
  virtual void emitMovSP(unsigned Reg, int64_t Offset = 0);
  virtual void emitPad(int64_t Offset);
  virtual void emitRegSave(const SmallVectorImpl<unsigned> &RegList,
                           bool isVector);
  virtual void emitUnwindRaw(int64_t StackOffset,
                             const SmallVectorImpl<uint8_t> &Opcodes);

  virtual void switchVendor(StringRef Vendor);
  virtual void emitAttribute(unsigned Attribute, unsigned Value);
  virtual void emitTextAttribute(unsigned Attribute, StringRef String);
  virtual void emitIntTextAttribute(unsigned Attribute, unsigned IntValue,
                                    StringRef StringValue = "");
  virtual void emitFPU(unsigned FPU);
  virtual void emitArch(ARM::ArchKind Arch);
  virtual void emitArchExtension(uint64_t ArchExt);
  virtual void emitObjectArch(ARM::ArchKind Arch);
  void emitTargetAttributes(const MCSubtargetInfo &STI);
  virtual void finishAttributeSection();
  virtual void emitInst(uint32_t Inst, char Suffix = '\0');

  virtual void AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *SRE);

  virtual void emitThumbSet(MCSymbol *Symbol, const MCExpr *Value);

  void emitConstantPools() override;

  /// Reset any state between object emissions, i.e. the equivalent of
  /// MCStreamer's reset method.
  virtual void reset();

  /// Callback used to implement the ldr= pseudo.
  /// Add a new entry to the constant pool for the current section and return an
  /// MCExpr that can be used to refer to the constant pool location.
  const MCExpr *addConstantPoolEntry(const MCExpr *, SMLoc Loc);

  /// Callback used to implement the .ltorg directive.
  /// Emit contents of constant pool for the current section.
  void emitCurrentConstantPool();

private:
  std::unique_ptr<AssemblerConstantPools> ConstantPools;
};

/// Streaming machine code generation interface.
///
/// This interface is intended to provide a programmatic 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;
  std::unique_ptr<MCTargetStreamer> TargetStreamer;

  std::vector<MCDwarfFrameInfo> DwarfFrameInfos;
  MCDwarfFrameInfo *getCurrentDwarfFrameInfo();

  /// Similar to DwarfFrameInfos, but for SEH unwind info. Chained frames may
  /// refer to each other, so use std::unique_ptr to provide pointer stability.
  std::vector<std::unique_ptr<WinEH::FrameInfo>> WinFrameInfos;

  WinEH::FrameInfo *CurrentWinFrameInfo;
  size_t CurrentProcWinFrameInfoStartIndex;

  /// Tracks an index to represent the order a symbol was emitted in.
  /// Zero means we did not emit that symbol.
  DenseMap<const MCSymbol *, unsigned> SymbolOrdering;

  /// This is stack of current and previous section values saved by
  /// PushSection.
  SmallVector<std::pair<MCSectionSubPair, MCSectionSubPair>, 4> SectionStack;

  /// Pointer to the parser's SMLoc if available. This is used to provide
  /// locations for diagnostics.
  const SMLoc *StartTokLocPtr = nullptr;

  /// The next unique ID to use when creating a WinCFI-related section (.pdata
  /// or .xdata). This ID ensures that we have a one-to-one mapping from
  /// code section to unwind info section, which MSVC's incremental linker
  /// requires.
  unsigned NextWinCFIID = 0;

  bool UseAssemblerInfoForParsing;

  /// Is the assembler allowed to insert padding automatically?  For
  /// correctness reasons, we sometimes need to ensure instructions aren't
  /// separated in unexpected ways.  At the moment, this feature is only
  /// useable from an integrated assembler, but assembly syntax is under
  /// discussion for future inclusion.
  bool AllowAutoPadding = false;

protected:
  MCStreamer(MCContext &Ctx);

  virtual void emitCFIStartProcImpl(MCDwarfFrameInfo &Frame);
  virtual void emitCFIEndProcImpl(MCDwarfFrameInfo &CurFrame);

  WinEH::FrameInfo *getCurrentWinFrameInfo() {
    return CurrentWinFrameInfo;
  }

  virtual void EmitWindowsUnwindTables(WinEH::FrameInfo *Frame);

  virtual void EmitWindowsUnwindTables();

  virtual void emitRawTextImpl(StringRef String);

  /// Returns true if the the .cv_loc directive is in the right section.
  bool checkCVLocSection(unsigned FuncId, unsigned FileNo, SMLoc Loc);

public:
  MCStreamer(const MCStreamer &) = delete;
  MCStreamer &operator=(const MCStreamer &) = delete;
  virtual ~MCStreamer();

  void visitUsedExpr(const MCExpr &Expr);
  virtual void visitUsedSymbol(const MCSymbol &Sym);

  void setTargetStreamer(MCTargetStreamer *TS) {
    TargetStreamer.reset(TS);
  }

  void setStartTokLocPtr(const SMLoc *Loc) { StartTokLocPtr = Loc; }
  SMLoc getStartTokLoc() const {
    return StartTokLocPtr ? *StartTokLocPtr : SMLoc();
  }

  /// State management
  ///
  virtual void reset();

  MCContext &getContext() const { return Context; }

  virtual MCAssembler *getAssemblerPtr() { return nullptr; }

  void setUseAssemblerInfoForParsing(bool v) { UseAssemblerInfoForParsing = v; }
  bool getUseAssemblerInfoForParsing() { return UseAssemblerInfoForParsing; }

  MCTargetStreamer *getTargetStreamer() {
    return TargetStreamer.get();
  }

  void setAllowAutoPadding(bool v) { AllowAutoPadding = v; }
  bool getAllowAutoPadding() const { return AllowAutoPadding; }

  /// When emitting an object file, create and emit a real label. When emitting
  /// textual assembly, this should do nothing to avoid polluting our output.
  virtual MCSymbol *emitCFILabel();

  /// Retrieve the current frame info if one is available and it is not yet
  /// closed. Otherwise, issue an error and return null.
  WinEH::FrameInfo *EnsureValidWinFrameInfo(SMLoc Loc);

  unsigned getNumFrameInfos();
  ArrayRef<MCDwarfFrameInfo> getDwarfFrameInfos() const;

  bool hasUnfinishedDwarfFrameInfo();

  unsigned getNumWinFrameInfos() { return WinFrameInfos.size(); }
  ArrayRef<std::unique_ptr<WinEH::FrameInfo>> getWinFrameInfos() const {
    return WinFrameInfos;
  }

  void generateCompactUnwindEncodings(MCAsmBackend *MAB);

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

  /// Return true if this streamer supports verbose assembly and if it is
  /// enabled.
  virtual bool isVerboseAsm() const { return false; }

  /// Return true if this asm streamer supports emitting unformatted text
  /// to the .s file with EmitRawText.
  virtual bool hasRawTextSupport() const { return false; }

  /// Is the integrated assembler required for this streamer to function
  /// correctly?
  virtual bool isIntegratedAssemblerRequired() const { return false; }

  /// Add a textual comment.
  ///
  /// Typically for comments 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.
  /// By default, each comment is terminated with an end of line, i.e. the
  /// EOL param is set to true by default. If one prefers not to end the
  /// comment with a new line then the EOL param should be passed
  /// with a false value.
  virtual void AddComment(const Twine &T, bool EOL = true) {}

  /// 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();

  /// Print T and prefix it with the comment string (normally #) and
  /// optionally a tab. This prints the comment immediately, not at the end of
  /// the current line. It is basically a safe version of EmitRawText: since it
  /// only prints comments, the object streamer ignores it instead of asserting.
  virtual void emitRawComment(const Twine &T, bool TabPrefix = true);

  /// Add explicit comment T. T is required to be a valid
  /// comment in the output and does not need to be escaped.
  virtual void addExplicitComment(const Twine &T);

  /// Emit added explicit comments.
  virtual void emitExplicitComments();

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

  /// @}

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

  /// Return the current section that the streamer is emitting code to.
  MCSectionSubPair getCurrentSection() const {
    if (!SectionStack.empty())
      return SectionStack.back().first;
    return MCSectionSubPair();
  }
  MCSection *getCurrentSectionOnly() const { return getCurrentSection().first; }

  /// Return the previous section that the streamer is emitting code to.
  MCSectionSubPair getPreviousSection() const {
    if (!SectionStack.empty())
      return SectionStack.back().second;
    return MCSectionSubPair();
  }

  /// Returns an index to represent the order a symbol was emitted in.
  /// (zero if we did not emit that symbol)
  unsigned GetSymbolOrder(const MCSymbol *Sym) const {
    return SymbolOrdering.lookup(Sym);
  }

  /// Update streamer for a new active section.
  ///
  /// This is called by PopSection and SwitchSection, if the current
  /// section changes.
  virtual void changeSection(MCSection *, const MCExpr *);

  /// Save the current and previous section on the section stack.
  void PushSection() {
    SectionStack.push_back(
        std::make_pair(getCurrentSection(), getPreviousSection()));
  }

  /// Restore the current and previous section from the section stack.
  /// Calls changeSection as needed.
  ///
  /// Returns false if the stack was empty.
  bool PopSection() {
    if (SectionStack.size() <= 1)
      return false;
    auto I = SectionStack.end();
    --I;
    MCSectionSubPair OldSection = I->first;
    --I;
    MCSectionSubPair NewSection = I->first;

    if (NewSection.first && OldSection != NewSection)
      changeSection(NewSection.first, NewSection.second);
    SectionStack.pop_back();
    return true;
  }

  bool SubSection(const MCExpr *Subsection) {
    if (SectionStack.empty())
      return false;

    SwitchSection(SectionStack.back().first.first, Subsection);
    return true;
  }

  /// 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(MCSection *Section,
                             const MCExpr *Subsection = nullptr);

  /// Set the current section where code is being emitted to \p Section.
  /// This is required to update CurSection. This version does not call
  /// changeSection.
  void SwitchSectionNoChange(MCSection *Section,
                             const MCExpr *Subsection = nullptr) {
    assert(Section && "Cannot switch to a null section!");
    MCSectionSubPair curSection = SectionStack.back().first;
    SectionStack.back().second = curSection;
    if (MCSectionSubPair(Section, Subsection) != curSection)
      SectionStack.back().first = MCSectionSubPair(Section, Subsection);
  }

  /// Create the default sections and set the initial one.
  virtual void initSections(bool NoExecStack, const MCSubtargetInfo &STI);

  MCSymbol *endSection(MCSection *Section);

  /// Sets the symbol's section.
  ///
  /// Each emitted symbol will be tracked in the ordering table,
  /// so we can sort on them later.
  void AssignFragment(MCSymbol *Symbol, MCFragment *Fragment);

  /// Returns the mnemonic for \p MI, if the streamer has access to a
  /// instruction printer and returns an empty string otherwise.
  virtual StringRef getMnemonic(MCInst &MI) { return ""; }

  /// 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.
  // FIXME: These emission are non-const because we mutate the symbol to
  // add the section we're emitting it to later.
  virtual void emitLabel(MCSymbol *Symbol, SMLoc Loc = SMLoc());

  virtual void emitEHSymAttributes(const MCSymbol *Symbol, MCSymbol *EHSymbol);

  /// Note in the output the specified \p Flag.
  virtual void emitAssemblerFlag(MCAssemblerFlag Flag);

  /// Emit the given list \p Options of strings as linker
  /// options into the output.
  virtual void emitLinkerOptions(ArrayRef<std::string> Kind) {}

  /// Note in the output the specified region \p Kind.
  virtual void emitDataRegion(MCDataRegionType Kind) {}

  /// Specify the Mach-O minimum deployment target version.
  virtual void emitVersionMin(MCVersionMinType Type, unsigned Major,
                              unsigned Minor, unsigned Update,
                              VersionTuple SDKVersion) {}

  /// Emit/Specify Mach-O build version command.
  /// \p Platform should be one of MachO::PlatformType.
  virtual void emitBuildVersion(unsigned Platform, unsigned Major,
                                unsigned Minor, unsigned Update,
                                VersionTuple SDKVersion) {}

  virtual void emitDarwinTargetVariantBuildVersion(unsigned Platform,
                                                   unsigned Major,
                                                   unsigned Minor,
                                                   unsigned Update,
                                                   VersionTuple SDKVersion) {}

  void emitVersionForTarget(const Triple &Target,
                            const VersionTuple &SDKVersion,
                            const Triple *DarwinTargetVariantTriple,
                            const VersionTuple &DarwinTargetVariantSDKVersion);

  /// Note in the output that the specified \p Func is a Thumb mode
  /// function (ARM target only).
  virtual void emitThumbFunc(MCSymbol *Func);

  /// 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);

  /// Emit an assignment of \p Value to \p Symbol, but only if \p Value is also
  /// emitted.
  virtual void emitConditionalAssignment(MCSymbol *Symbol, const MCExpr *Value);

  /// Emit an weak reference from \p Alias to \p Symbol.
  ///
  /// This corresponds to an assembler statement such as:
  ///  .weakref alias, symbol
  ///
  /// \param Alias - The alias that is being created.
  /// \param Symbol - The symbol being aliased.
  virtual void emitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol);

  /// Add the given \p Attribute to \p Symbol.
  virtual bool emitSymbolAttribute(MCSymbol *Symbol,
                                   MCSymbolAttr Attribute) = 0;

  /// 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);

  /// Start emitting COFF symbol definition
  ///
  /// \param Symbol - The symbol to have its External & Type fields set.
  virtual void BeginCOFFSymbolDef(const MCSymbol *Symbol);

  /// Emit the storage class of the symbol.
  ///
  /// \param StorageClass - The storage class the symbol should have.
  virtual void EmitCOFFSymbolStorageClass(int StorageClass);

  /// Emit the type of the symbol.
  ///
  /// \param Type - A COFF type identifier (see COFF::SymbolType in X86COFF.h)
  virtual void EmitCOFFSymbolType(int Type);

  /// Marks the end of the symbol definition.
  virtual void EndCOFFSymbolDef();

  virtual void EmitCOFFSafeSEH(MCSymbol const *Symbol);

  /// Emits the symbol table index of a Symbol into the current section.
  virtual void EmitCOFFSymbolIndex(MCSymbol const *Symbol);

  /// Emits a COFF section index.
  ///
  /// \param Symbol - Symbol the section number relocation should point to.
  virtual void EmitCOFFSectionIndex(MCSymbol const *Symbol);

  /// Emits a COFF section relative relocation.
  ///
  /// \param Symbol - Symbol the section relative relocation should point to.
  virtual void EmitCOFFSecRel32(MCSymbol const *Symbol, uint64_t Offset);

  /// Emits a COFF image relative relocation.
  ///
  /// \param Symbol - Symbol the image relative relocation should point to.
  virtual void EmitCOFFImgRel32(MCSymbol const *Symbol, int64_t Offset);

  /// Emits an lcomm directive with XCOFF csect information.
  ///
  /// \param LabelSym - Label on the block of storage.
  /// \param Size - The size of the block of storage.
  /// \param CsectSym - Csect name for the block of storage.
  /// \param ByteAlignment - The alignment of the symbol in bytes. Must be a
  /// power of 2.
  virtual void emitXCOFFLocalCommonSymbol(MCSymbol *LabelSym, uint64_t Size,
                                          MCSymbol *CsectSym,
                                          unsigned ByteAlignment);

  /// Emit a symbol's linkage and visibility with a linkage directive for XCOFF.
  ///
  /// \param Symbol - The symbol to emit.
  /// \param Linkage - The linkage of the symbol to emit.
  /// \param Visibility - The visibility of the symbol to emit or MCSA_Invalid
  /// if the symbol does not have an explicit visibility.
  virtual void emitXCOFFSymbolLinkageWithVisibility(MCSymbol *Symbol,
                                                    MCSymbolAttr Linkage,
                                                    MCSymbolAttr Visibility);

  /// Emit a XCOFF .rename directive which creates a synonym for an illegal or
  /// undesirable name.
  ///
  /// \param Name - The name used internally in the assembly for references to
  /// the symbol.
  /// \param Rename - The value to which the Name parameter is
  /// changed at the end of assembly.
  virtual void emitXCOFFRenameDirective(const MCSymbol *Name, StringRef Rename);

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

  /// Emit an ELF .symver directive.
  ///
  /// This corresponds to an assembler statement such as:
  ///  .symver _start, foo@@SOME_VERSION
  virtual void emitELFSymverDirective(const MCSymbol *OriginalSym,
                                      StringRef Name, bool KeepOriginalSym);

  /// Emit a Linker Optimization Hint (LOH) directive.
  /// \param Args - Arguments of the LOH.
  virtual void emitLOHDirective(MCLOHType Kind, const MCLOHArgs &Args) {}

  /// Emit a .gnu_attribute directive.
  virtual void emitGNUAttribute(unsigned Tag, unsigned Value) {}

  /// 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;

  /// Emit a local common (.lcomm) symbol.
  ///
  /// \param Symbol - The common symbol to emit.
  /// \param Size - The size of the common symbol.
  /// \param ByteAlignment - The alignment of the common symbol in bytes.
  virtual void emitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
                                     unsigned ByteAlignment);

  /// Emit the zerofill section and an optional 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(MCSection *Section, MCSymbol *Symbol = nullptr,
                            uint64_t Size = 0, unsigned ByteAlignment = 0,
                            SMLoc Loc = SMLoc()) = 0;

  /// Emit a thread local bss (.tbss) symbol.
  ///
  /// \param Section - The thread local common section.
  /// \param Symbol - The thread local common symbol to emit.
  /// \param Size - The size of the symbol.
  /// \param ByteAlignment - The alignment of the thread local common symbol
  /// if non-zero.  This must be a power of 2 on some targets.
  virtual void emitTBSSSymbol(MCSection *Section, MCSymbol *Symbol,
                              uint64_t Size, unsigned ByteAlignment = 0);

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

  /// Emit the bytes in \p Data into the output.
  ///
  /// This is used to implement assembler directives such as .byte, .ascii,
  /// etc.
  virtual void emitBytes(StringRef Data);

  /// Functionally identical to EmitBytes. When emitting textual assembly, this
  /// method uses .byte directives instead of .ascii or .asciz for readability.
  virtual void emitBinaryData(StringRef Data);

  /// 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.
  /// \param Loc - The location of the expression for error reporting.
  virtual void emitValueImpl(const MCExpr *Value, unsigned Size,
                             SMLoc Loc = SMLoc());

  void emitValue(const MCExpr *Value, unsigned Size, SMLoc Loc = SMLoc());

  /// 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);
  virtual void emitIntValue(APInt Value);

  /// Special case of EmitValue that avoids the client having to pass
  /// in a MCExpr for constant integers & prints in Hex format for certain
  /// modes.
  virtual void emitIntValueInHex(uint64_t Value, unsigned Size) {
    emitIntValue(Value, Size);
  }

  void emitInt8(uint64_t Value) { emitIntValue(Value, 1); }
  void emitInt16(uint64_t Value) { emitIntValue(Value, 2); }
  void emitInt32(uint64_t Value) { emitIntValue(Value, 4); }
  void emitInt64(uint64_t Value) { emitIntValue(Value, 8); }

  /// Special case of EmitValue that avoids the client having to pass
  /// in a MCExpr for constant integers & prints in Hex format for certain
  /// modes, pads the field with leading zeros to Size width
  virtual void emitIntValueInHexWithPadding(uint64_t Value, unsigned Size) {
    emitIntValue(Value, Size);
  }

  virtual void emitULEB128Value(const MCExpr *Value);

  virtual void emitSLEB128Value(const MCExpr *Value);

  /// Special case of EmitULEB128Value that avoids the client having to
  /// pass in a MCExpr for constant integers.
  void emitULEB128IntValue(uint64_t Value, unsigned PadTo = 0);

  /// Special case of EmitSLEB128Value that avoids the client having to
  /// pass in a MCExpr for constant integers.
  void emitSLEB128IntValue(int64_t Value);

  /// Special case of EmitValue that avoids the client having to pass in
  /// a MCExpr for MCSymbols.
  void emitSymbolValue(const MCSymbol *Sym, unsigned Size,
                       bool IsSectionRelative = false);

  /// Emit the expression \p Value into the output as a dtprel
  /// (64-bit DTP relative) value.
  ///
  /// This is used to implement assembler directives such as .dtpreldword on
  /// targets that support them.
  virtual void emitDTPRel64Value(const MCExpr *Value);

  /// Emit the expression \p Value into the output as a dtprel
  /// (32-bit DTP relative) value.
  ///
  /// This is used to implement assembler directives such as .dtprelword on
  /// targets that support them.
  virtual void emitDTPRel32Value(const MCExpr *Value);

  /// Emit the expression \p Value into the output as a tprel
  /// (64-bit TP relative) value.
  ///
  /// This is used to implement assembler directives such as .tpreldword on
  /// targets that support them.
  virtual void emitTPRel64Value(const MCExpr *Value);

  /// Emit the expression \p Value into the output as a tprel
  /// (32-bit TP relative) value.
  ///
  /// This is used to implement assembler directives such as .tprelword on
  /// targets that support them.
  virtual void emitTPRel32Value(const MCExpr *Value);

  /// Emit the expression \p Value into the output as a gprel64 (64-bit
  /// GP relative) value.
  ///
  /// This is used to implement assembler directives such as .gpdword on
  /// targets that support them.
  virtual void emitGPRel64Value(const MCExpr *Value);

  /// 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);

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

  /// Emit \p Size bytes worth of the value specified by \p FillValue.
  ///
  /// This is used to implement assembler directives such as .space or .skip.
  ///
  /// \param NumBytes - The number of bytes to emit.
  /// \param FillValue - The value to use when filling bytes.
  /// \param Loc - The location of the expression for error reporting.
  virtual void emitFill(const MCExpr &NumBytes, uint64_t FillValue,
                        SMLoc Loc = SMLoc());

  /// Emit \p NumValues copies of \p Size bytes. Each \p Size bytes is
  /// taken from the lowest order 4 bytes of \p Expr expression.
  ///
  /// This is used to implement assembler directives such as .fill.
  ///
  /// \param NumValues - The number of copies of \p Size bytes to emit.
  /// \param Size - The size (in bytes) of each repeated value.
  /// \param Expr - The expression from which \p Size bytes are used.
  virtual void emitFill(const MCExpr &NumValues, int64_t Size, int64_t Expr,
                        SMLoc Loc = SMLoc());

  virtual void emitNops(int64_t NumBytes, int64_t ControlledNopLength,
                        SMLoc Loc, const MCSubtargetInfo& STI);

  /// Emit NumBytes worth of zeros.
  /// This function properly handles data in virtual sections.
  void emitZeros(uint64_t NumBytes);

  /// 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);

  /// 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 STI - The MCSubtargetInfo in operation when padding is emitted.
  /// \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,
                                 const MCSubtargetInfo *STI,
                                 unsigned MaxBytesToEmit = 0);

  /// 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,
                                 SMLoc Loc);

  /// @}

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

  /// Emit ".file assembler diretive with additioal info.
  virtual void emitFileDirective(StringRef Filename, StringRef CompilerVerion,
                                 StringRef TimeStamp, StringRef Description);

  /// Emit the "identifiers" directive.  This implements the
  /// '.ident "version foo"' assembler directive.
  virtual void emitIdent(StringRef IdentString) {}

  /// Associate a filename with a specified logical file number.  This
  /// implements the DWARF2 '.file 4 "foo.c"' assembler directive.
  unsigned emitDwarfFileDirective(unsigned FileNo, StringRef Directory,
                                  StringRef Filename,
                                  Optional<MD5::MD5Result> Checksum = None,
                                  Optional<StringRef> Source = None,
                                  unsigned CUID = 0) {
    return cantFail(
        tryEmitDwarfFileDirective(FileNo, Directory, Filename, Checksum,
                                  Source, CUID));
  }

  /// Associate a filename with a specified logical file number.
  /// Also associate a directory, optional checksum, and optional source
  /// text with the logical file.  This implements the DWARF2
  /// '.file 4 "dir/foo.c"' assembler directive, and the DWARF5
  /// '.file 4 "dir/foo.c" md5 "..." source "..."' assembler directive.
  virtual Expected<unsigned> tryEmitDwarfFileDirective(
      unsigned FileNo, StringRef Directory, StringRef Filename,
      Optional<MD5::MD5Result> Checksum = None, Optional<StringRef> Source = None,
      unsigned CUID = 0);

  /// Specify the "root" file of the compilation, using the ".file 0" extension.
  virtual void emitDwarfFile0Directive(StringRef Directory, StringRef Filename,
                                       Optional<MD5::MD5Result> Checksum,
                                       Optional<StringRef> Source,
                                       unsigned CUID = 0);

  virtual void emitCFIBKeyFrame();

  /// This implements the DWARF2 '.loc fileno lineno ...' assembler
  /// directive.
  virtual void emitDwarfLocDirective(unsigned FileNo, unsigned Line,
                                     unsigned Column, unsigned Flags,
                                     unsigned Isa, unsigned Discriminator,
                                     StringRef FileName);

  /// Associate a filename with a specified logical file number, and also
  /// specify that file's checksum information.  This implements the '.cv_file 4
  /// "foo.c"' assembler directive. Returns true on success.
  virtual bool EmitCVFileDirective(unsigned FileNo, StringRef Filename,
                                   ArrayRef<uint8_t> Checksum,
                                   unsigned ChecksumKind);

  /// Introduces a function id for use with .cv_loc.
  virtual bool EmitCVFuncIdDirective(unsigned FunctionId);

  /// Introduces an inline call site id for use with .cv_loc. Includes
  /// extra information for inline line table generation.
  virtual bool EmitCVInlineSiteIdDirective(unsigned FunctionId, unsigned IAFunc,
                                           unsigned IAFile, unsigned IALine,
                                           unsigned IACol, SMLoc Loc);

  /// This implements the CodeView '.cv_loc' assembler directive.
  virtual void emitCVLocDirective(unsigned FunctionId, unsigned FileNo,
                                  unsigned Line, unsigned Column,
                                  bool PrologueEnd, bool IsStmt,
                                  StringRef FileName, SMLoc Loc);

  /// This implements the CodeView '.cv_linetable' assembler directive.
  virtual void emitCVLinetableDirective(unsigned FunctionId,
                                        const MCSymbol *FnStart,
                                        const MCSymbol *FnEnd);

  /// This implements the CodeView '.cv_inline_linetable' assembler
  /// directive.
  virtual void emitCVInlineLinetableDirective(unsigned PrimaryFunctionId,
                                              unsigned SourceFileId,
                                              unsigned SourceLineNum,
                                              const MCSymbol *FnStartSym,
                                              const MCSymbol *FnEndSym);

  /// This implements the CodeView '.cv_def_range' assembler
  /// directive.
  virtual void emitCVDefRangeDirective(
      ArrayRef<std::pair<const MCSymbol *, const MCSymbol *>> Ranges,
      StringRef FixedSizePortion);

  virtual void emitCVDefRangeDirective(
      ArrayRef<std::pair<const MCSymbol *, const MCSymbol *>> Ranges,
      codeview::DefRangeRegisterRelHeader DRHdr);

  virtual void emitCVDefRangeDirective(
      ArrayRef<std::pair<const MCSymbol *, const MCSymbol *>> Ranges,
      codeview::DefRangeSubfieldRegisterHeader DRHdr);

  virtual void emitCVDefRangeDirective(
      ArrayRef<std::pair<const MCSymbol *, const MCSymbol *>> Ranges,
      codeview::DefRangeRegisterHeader DRHdr);

  virtual void emitCVDefRangeDirective(
      ArrayRef<std::pair<const MCSymbol *, const MCSymbol *>> Ranges,
      codeview::DefRangeFramePointerRelHeader DRHdr);

  /// This implements the CodeView '.cv_stringtable' assembler directive.
  virtual void emitCVStringTableDirective() {}

  /// This implements the CodeView '.cv_filechecksums' assembler directive.
  virtual void emitCVFileChecksumsDirective() {}

  /// This implements the CodeView '.cv_filechecksumoffset' assembler
  /// directive.
  virtual void emitCVFileChecksumOffsetDirective(unsigned FileNo) {}

  /// This implements the CodeView '.cv_fpo_data' assembler directive.
  virtual void EmitCVFPOData(const MCSymbol *ProcSym, SMLoc Loc = {}) {}

  /// Emit the absolute difference between two symbols.
  ///
  /// \pre Offset of \c Hi is greater than the offset \c Lo.
  virtual void emitAbsoluteSymbolDiff(const MCSymbol *Hi, const MCSymbol *Lo,
                                      unsigned Size);

  /// Emit the absolute difference between two symbols encoded with ULEB128.
  virtual void emitAbsoluteSymbolDiffAsULEB128(const MCSymbol *Hi,
                                               const MCSymbol *Lo);

  virtual MCSymbol *getDwarfLineTableSymbol(unsigned CUID);
  virtual void emitCFISections(bool EH, bool Debug);
  void emitCFIStartProc(bool IsSimple, SMLoc Loc = SMLoc());
  void emitCFIEndProc();
  virtual void emitCFIDefCfa(int64_t Register, int64_t Offset);
  virtual void emitCFIDefCfaOffset(int64_t Offset);
  virtual void emitCFIDefCfaRegister(int64_t Register);
  virtual void emitCFILLVMDefAspaceCfa(int64_t Register, int64_t Offset,
                                       int64_t AddressSpace);
  virtual void emitCFIOffset(int64_t Register, int64_t Offset);
  virtual void emitCFIPersonality(const MCSymbol *Sym, unsigned Encoding);
  virtual void emitCFILsda(const MCSymbol *Sym, unsigned Encoding);
  virtual void emitCFIRememberState();
  virtual void emitCFIRestoreState();
  virtual void emitCFISameValue(int64_t Register);
  virtual void emitCFIRestore(int64_t Register);
  virtual void emitCFIRelOffset(int64_t Register, int64_t Offset);
  virtual void emitCFIAdjustCfaOffset(int64_t Adjustment);
  virtual void emitCFIEscape(StringRef Values);
  virtual void emitCFIReturnColumn(int64_t Register);
  virtual void emitCFIGnuArgsSize(int64_t Size);
  virtual void emitCFISignalFrame();
  virtual void emitCFIUndefined(int64_t Register);
  virtual void emitCFIRegister(int64_t Register1, int64_t Register2);
  virtual void emitCFIWindowSave();
  virtual void emitCFINegateRAState();

  virtual void EmitWinCFIStartProc(const MCSymbol *Symbol, SMLoc Loc = SMLoc());
  virtual void EmitWinCFIEndProc(SMLoc Loc = SMLoc());
  /// This is used on platforms, such as Windows on ARM64, that require function
  /// or funclet sizes to be emitted in .xdata before the End marker is emitted
  /// for the frame.  We cannot use the End marker, as it is not set at the
  /// point of emitting .xdata, in order to indicate that the frame is active.
  virtual void EmitWinCFIFuncletOrFuncEnd(SMLoc Loc = SMLoc());
  virtual void EmitWinCFIStartChained(SMLoc Loc = SMLoc());
  virtual void EmitWinCFIEndChained(SMLoc Loc = SMLoc());
  virtual void EmitWinCFIPushReg(MCRegister Register, SMLoc Loc = SMLoc());
  virtual void EmitWinCFISetFrame(MCRegister Register, unsigned Offset,
                                  SMLoc Loc = SMLoc());
  virtual void EmitWinCFIAllocStack(unsigned Size, SMLoc Loc = SMLoc());
  virtual void EmitWinCFISaveReg(MCRegister Register, unsigned Offset,
                                 SMLoc Loc = SMLoc());
  virtual void EmitWinCFISaveXMM(MCRegister Register, unsigned Offset,
                                 SMLoc Loc = SMLoc());
  virtual void EmitWinCFIPushFrame(bool Code, SMLoc Loc = SMLoc());
  virtual void EmitWinCFIEndProlog(SMLoc Loc = SMLoc());
  virtual void EmitWinEHHandler(const MCSymbol *Sym, bool Unwind, bool Except,
                                SMLoc Loc = SMLoc());
  virtual void EmitWinEHHandlerData(SMLoc Loc = SMLoc());

  virtual void emitCGProfileEntry(const MCSymbolRefExpr *From,
                                  const MCSymbolRefExpr *To, uint64_t Count);

  /// Get the .pdata section used for the given section. Typically the given
  /// section is either the main .text section or some other COMDAT .text
  /// section, but it may be any section containing code.
  MCSection *getAssociatedPDataSection(const MCSection *TextSec);

  /// Get the .xdata section used for the given section.
  MCSection *getAssociatedXDataSection(const MCSection *TextSec);

  virtual void emitSyntaxDirective();

  /// Record a relocation described by the .reloc directive. Return None if
  /// succeeded. Otherwise, return a pair (Name is invalid, error message).
  virtual Optional<std::pair<bool, std::string>>
  emitRelocDirective(const MCExpr &Offset, StringRef Name, const MCExpr *Expr,
                     SMLoc Loc, const MCSubtargetInfo &STI) {
    return None;
  }

  virtual void emitAddrsig() {}
  virtual void emitAddrsigSym(const MCSymbol *Sym) {}

  /// Emit the given \p Instruction into the current section.
  virtual void emitInstruction(const MCInst &Inst, const MCSubtargetInfo &STI);

  /// Emit the a pseudo probe into the current section.
  virtual void emitPseudoProbe(uint64_t Guid, uint64_t Index, uint64_t Type,
                               uint64_t Attr,
                               const MCPseudoProbeInlineStack &InlineStack);

  /// Set the bundle alignment mode from now on in the section.
  /// The argument is the power of 2 to which the alignment is set. The
  /// value 0 means turn the bundle alignment off.
  virtual void emitBundleAlignMode(unsigned AlignPow2);

  /// The following instructions are a bundle-locked group.
  ///
  /// \param AlignToEnd - If true, the bundle-locked group will be aligned to
  ///                     the end of a bundle.
  virtual void emitBundleLock(bool AlignToEnd);

  /// Ends a bundle-locked group.
  virtual void emitBundleUnlock();

  /// If this file is backed by a assembly streamer, this dumps the
  /// specified string in the output .s file.  This capability is indicated by
  /// the hasRawTextSupport() predicate.  By default this aborts.
  void emitRawText(const Twine &String);

  /// Streamer specific finalization.
  virtual void finishImpl();
  /// Finish emission of machine code.
  void Finish(SMLoc EndLoc = SMLoc());

  virtual bool mayHaveInstructions(MCSection &Sec) const { return true; }

  /// Emit a special value of 0xffffffff if producing 64-bit debugging info.
  void maybeEmitDwarf64Mark();

  /// Emit a unit length field. The actual format, DWARF32 or DWARF64, is chosen
  /// according to the settings.
  virtual void emitDwarfUnitLength(uint64_t Length, const Twine &Comment);

  /// Emit a unit length field. The actual format, DWARF32 or DWARF64, is chosen
  /// according to the settings.
  /// Return the end symbol generated inside, the caller needs to emit it.
  virtual MCSymbol *emitDwarfUnitLength(const Twine &Prefix,
                                        const Twine &Comment);

  /// Emit the debug line start label.
  virtual void emitDwarfLineStartLabel(MCSymbol *StartSym);

  /// Emit the debug line end entry.
  virtual void emitDwarfLineEndEntry(MCSection *Section, MCSymbol *LastLabel) {}

  /// If targets does not support representing debug line section by .loc/.file
  /// directives in assembly output, we need to populate debug line section with
  /// raw debug line contents.
  virtual void emitDwarfAdvanceLineAddr(int64_t LineDelta,
                                        const MCSymbol *LastLabel,
                                        const MCSymbol *Label,
                                        unsigned PointerSize) {}

  /// Do finalization for the streamer at the end of a section.
  virtual void doFinalizationAtSectionEnd(MCSection *Section) {}
};

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

} // end namespace llvm

#endif // LLVM_MC_MCSTREAMER_H

#ifdef __GNUC__
#pragma GCC diagnostic pop
#endif