ARMELFStreamer.cpp revision 360660 
1//===- lib/MC/ARMELFStreamer.cpp - ELF Object Output for ARM --------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8//
9// This file assembles .s files and emits ARM ELF .o object files. Different
10// from generic ELF streamer in emitting mapping symbols ($a, $t and $d) to
11// delimit regions of data and code.
12//
13//===----------------------------------------------------------------------===//
14
15#include "ARMRegisterInfo.h"
16#include "ARMUnwindOpAsm.h"
17#include "llvm/ADT/DenseMap.h"
18#include "llvm/ADT/SmallString.h"
19#include "llvm/ADT/SmallVector.h"
20#include "llvm/ADT/StringRef.h"
21#include "llvm/ADT/Triple.h"
22#include "llvm/ADT/Twine.h"
23#include "llvm/BinaryFormat/ELF.h"
24#include "llvm/MC/MCAsmBackend.h"
25#include "llvm/MC/MCAsmInfo.h"
26#include "llvm/MC/MCAssembler.h"
27#include "llvm/MC/MCCodeEmitter.h"
28#include "llvm/MC/MCContext.h"
29#include "llvm/MC/MCELFStreamer.h"
30#include "llvm/MC/MCExpr.h"
31#include "llvm/MC/MCFixup.h"
32#include "llvm/MC/MCFragment.h"
33#include "llvm/MC/MCInst.h"
34#include "llvm/MC/MCInstPrinter.h"
35#include "llvm/MC/MCObjectWriter.h"
36#include "llvm/MC/MCRegisterInfo.h"
37#include "llvm/MC/MCSection.h"
38#include "llvm/MC/MCSectionELF.h"
39#include "llvm/MC/MCStreamer.h"
40#include "llvm/MC/MCSubtargetInfo.h"
41#include "llvm/MC/MCSymbol.h"
42#include "llvm/MC/MCSymbolELF.h"
43#include "llvm/MC/SectionKind.h"
44#include "llvm/Support/ARMBuildAttributes.h"
45#include "llvm/Support/ARMEHABI.h"
46#include "llvm/Support/Casting.h"
47#include "llvm/Support/ErrorHandling.h"
48#include "llvm/Support/FormattedStream.h"
49#include "llvm/Support/LEB128.h"
50#include "llvm/Support/TargetParser.h"
51#include "llvm/Support/raw_ostream.h"
52#include <algorithm>
53#include <cassert>
54#include <climits>
55#include <cstddef>
56#include <cstdint>
57#include <string>
58
59using namespace llvm;
60
61static std::string GetAEABIUnwindPersonalityName(unsigned Index) {
62  assert(Index < ARM::EHABI::NUM_PERSONALITY_INDEX &&
63         "Invalid personality index");
64  return (Twine("__aeabi_unwind_cpp_pr") + Twine(Index)).str();
65}
66
67namespace {
68
69class ARMELFStreamer;
70
71class ARMTargetAsmStreamer : public ARMTargetStreamer {
72  formatted_raw_ostream &OS;
73  MCInstPrinter &InstPrinter;
74  bool IsVerboseAsm;
75
76  void emitFnStart() override;
77  void emitFnEnd() override;
78  void emitCantUnwind() override;
79  void emitPersonality(const MCSymbol *Personality) override;
80  void emitPersonalityIndex(unsigned Index) override;
81  void emitHandlerData() override;
82  void emitSetFP(unsigned FpReg, unsigned SpReg, int64_t Offset = 0) override;
83  void emitMovSP(unsigned Reg, int64_t Offset = 0) override;
84  void emitPad(int64_t Offset) override;
85  void emitRegSave(const SmallVectorImpl<unsigned> &RegList,
86                   bool isVector) override;
87  void emitUnwindRaw(int64_t Offset,
88                     const SmallVectorImpl<uint8_t> &Opcodes) override;
89
90  void switchVendor(StringRef Vendor) override;
91  void emitAttribute(unsigned Attribute, unsigned Value) override;
92  void emitTextAttribute(unsigned Attribute, StringRef String) override;
93  void emitIntTextAttribute(unsigned Attribute, unsigned IntValue,
94                            StringRef StringValue) override;
95  void emitArch(ARM::ArchKind Arch) override;
96  void emitArchExtension(unsigned ArchExt) override;
97  void emitObjectArch(ARM::ArchKind Arch) override;
98  void emitFPU(unsigned FPU) override;
99  void emitInst(uint32_t Inst, char Suffix = '\0') override;
100  void finishAttributeSection() override;
101
102  void AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *SRE) override;
103  void emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) override;
104
105public:
106  ARMTargetAsmStreamer(MCStreamer &S, formatted_raw_ostream &OS,
107                       MCInstPrinter &InstPrinter, bool VerboseAsm);
108};
109
110ARMTargetAsmStreamer::ARMTargetAsmStreamer(MCStreamer &S,
111                                           formatted_raw_ostream &OS,
112                                           MCInstPrinter &InstPrinter,
113                                           bool VerboseAsm)
114    : ARMTargetStreamer(S), OS(OS), InstPrinter(InstPrinter),
115      IsVerboseAsm(VerboseAsm) {}
116
117void ARMTargetAsmStreamer::emitFnStart() { OS << "\t.fnstart\n"; }
118void ARMTargetAsmStreamer::emitFnEnd() { OS << "\t.fnend\n"; }
119void ARMTargetAsmStreamer::emitCantUnwind() { OS << "\t.cantunwind\n"; }
120
121void ARMTargetAsmStreamer::emitPersonality(const MCSymbol *Personality) {
122  OS << "\t.personality " << Personality->getName() << '\n';
123}
124
125void ARMTargetAsmStreamer::emitPersonalityIndex(unsigned Index) {
126  OS << "\t.personalityindex " << Index << '\n';
127}
128
129void ARMTargetAsmStreamer::emitHandlerData() { OS << "\t.handlerdata\n"; }
130
131void ARMTargetAsmStreamer::emitSetFP(unsigned FpReg, unsigned SpReg,
132                                     int64_t Offset) {
133  OS << "\t.setfp\t";
134  InstPrinter.printRegName(OS, FpReg);
135  OS << ", ";
136  InstPrinter.printRegName(OS, SpReg);
137  if (Offset)
138    OS << ", #" << Offset;
139  OS << '\n';
140}
141
142void ARMTargetAsmStreamer::emitMovSP(unsigned Reg, int64_t Offset) {
143  assert((Reg != ARM::SP && Reg != ARM::PC) &&
144         "the operand of .movsp cannot be either sp or pc");
145
146  OS << "\t.movsp\t";
147  InstPrinter.printRegName(OS, Reg);
148  if (Offset)
149    OS << ", #" << Offset;
150  OS << '\n';
151}
152
153void ARMTargetAsmStreamer::emitPad(int64_t Offset) {
154  OS << "\t.pad\t#" << Offset << '\n';
155}
156
157void ARMTargetAsmStreamer::emitRegSave(const SmallVectorImpl<unsigned> &RegList,
158                                       bool isVector) {
159  assert(RegList.size() && "RegList should not be empty");
160  if (isVector)
161    OS << "\t.vsave\t{";
162  else
163    OS << "\t.save\t{";
164
165  InstPrinter.printRegName(OS, RegList[0]);
166
167  for (unsigned i = 1, e = RegList.size(); i != e; ++i) {
168    OS << ", ";
169    InstPrinter.printRegName(OS, RegList[i]);
170  }
171
172  OS << "}\n";
173}
174
175void ARMTargetAsmStreamer::switchVendor(StringRef Vendor) {}
176
177void ARMTargetAsmStreamer::emitAttribute(unsigned Attribute, unsigned Value) {
178  OS << "\t.eabi_attribute\t" << Attribute << ", " << Twine(Value);
179  if (IsVerboseAsm) {
180    StringRef Name = ARMBuildAttrs::AttrTypeAsString(Attribute);
181    if (!Name.empty())
182      OS << "\t@ " << Name;
183  }
184  OS << "\n";
185}
186
187void ARMTargetAsmStreamer::emitTextAttribute(unsigned Attribute,
188                                             StringRef String) {
189  switch (Attribute) {
190  case ARMBuildAttrs::CPU_name:
191    OS << "\t.cpu\t" << String.lower();
192    break;
193  default:
194    OS << "\t.eabi_attribute\t" << Attribute << ", \"" << String << "\"";
195    if (IsVerboseAsm) {
196      StringRef Name = ARMBuildAttrs::AttrTypeAsString(Attribute);
197      if (!Name.empty())
198        OS << "\t@ " << Name;
199    }
200    break;
201  }
202  OS << "\n";
203}
204
205void ARMTargetAsmStreamer::emitIntTextAttribute(unsigned Attribute,
206                                                unsigned IntValue,
207                                                StringRef StringValue) {
208  switch (Attribute) {
209  default: llvm_unreachable("unsupported multi-value attribute in asm mode");
210  case ARMBuildAttrs::compatibility:
211    OS << "\t.eabi_attribute\t" << Attribute << ", " << IntValue;
212    if (!StringValue.empty())
213      OS << ", \"" << StringValue << "\"";
214    if (IsVerboseAsm)
215      OS << "\t@ " << ARMBuildAttrs::AttrTypeAsString(Attribute);
216    break;
217  }
218  OS << "\n";
219}
220
221void ARMTargetAsmStreamer::emitArch(ARM::ArchKind Arch) {
222  OS << "\t.arch\t" << ARM::getArchName(Arch) << "\n";
223}
224
225void ARMTargetAsmStreamer::emitArchExtension(unsigned ArchExt) {
226  OS << "\t.arch_extension\t" << ARM::getArchExtName(ArchExt) << "\n";
227}
228
229void ARMTargetAsmStreamer::emitObjectArch(ARM::ArchKind Arch) {
230  OS << "\t.object_arch\t" << ARM::getArchName(Arch) << '\n';
231}
232
233void ARMTargetAsmStreamer::emitFPU(unsigned FPU) {
234  OS << "\t.fpu\t" << ARM::getFPUName(FPU) << "\n";
235}
236
237void ARMTargetAsmStreamer::finishAttributeSection() {}
238
239void
240ARMTargetAsmStreamer::AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *S) {
241  OS << "\t.tlsdescseq\t" << S->getSymbol().getName();
242}
243
244void ARMTargetAsmStreamer::emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) {
245  const MCAsmInfo *MAI = Streamer.getContext().getAsmInfo();
246
247  OS << "\t.thumb_set\t";
248  Symbol->print(OS, MAI);
249  OS << ", ";
250  Value->print(OS, MAI);
251  OS << '\n';
252}
253
254void ARMTargetAsmStreamer::emitInst(uint32_t Inst, char Suffix) {
255  OS << "\t.inst";
256  if (Suffix)
257    OS << "." << Suffix;
258  OS << "\t0x" << Twine::utohexstr(Inst) << "\n";
259}
260
261void ARMTargetAsmStreamer::emitUnwindRaw(int64_t Offset,
262                                      const SmallVectorImpl<uint8_t> &Opcodes) {
263  OS << "\t.unwind_raw " << Offset;
264  for (SmallVectorImpl<uint8_t>::const_iterator OCI = Opcodes.begin(),
265                                                OCE = Opcodes.end();
266       OCI != OCE; ++OCI)
267    OS << ", 0x" << Twine::utohexstr(*OCI);
268  OS << '\n';
269}
270
271class ARMTargetELFStreamer : public ARMTargetStreamer {
272private:
273  // This structure holds all attributes, accounting for
274  // their string/numeric value, so we can later emit them
275  // in declaration order, keeping all in the same vector
276  struct AttributeItem {
277    enum {
278      HiddenAttribute = 0,
279      NumericAttribute,
280      TextAttribute,
281      NumericAndTextAttributes
282    } Type;
283    unsigned Tag;
284    unsigned IntValue;
285    std::string StringValue;
286
287    static bool LessTag(const AttributeItem &LHS, const AttributeItem &RHS) {
288      // The conformance tag must be emitted first when serialised
289      // into an object file. Specifically, the addenda to the ARM ABI
290      // states that (2.3.7.4):
291      //
292      // "To simplify recognition by consumers in the common case of
293      // claiming conformity for the whole file, this tag should be
294      // emitted first in a file-scope sub-subsection of the first
295      // public subsection of the attributes section."
296      //
297      // So it is special-cased in this comparison predicate when the
298      // attributes are sorted in finishAttributeSection().
299      return (RHS.Tag != ARMBuildAttrs::conformance) &&
300             ((LHS.Tag == ARMBuildAttrs::conformance) || (LHS.Tag < RHS.Tag));
301    }
302  };
303
304  StringRef CurrentVendor;
305  unsigned FPU = ARM::FK_INVALID;
306  ARM::ArchKind Arch = ARM::ArchKind::INVALID;
307  ARM::ArchKind EmittedArch = ARM::ArchKind::INVALID;
308  SmallVector<AttributeItem, 64> Contents;
309
310  MCSection *AttributeSection = nullptr;
311
312  AttributeItem *getAttributeItem(unsigned Attribute) {
313    for (size_t i = 0; i < Contents.size(); ++i)
314      if (Contents[i].Tag == Attribute)
315        return &Contents[i];
316    return nullptr;
317  }
318
319  void setAttributeItem(unsigned Attribute, unsigned Value,
320                        bool OverwriteExisting) {
321    // Look for existing attribute item
322    if (AttributeItem *Item = getAttributeItem(Attribute)) {
323      if (!OverwriteExisting)
324        return;
325      Item->Type = AttributeItem::NumericAttribute;
326      Item->IntValue = Value;
327      return;
328    }
329
330    // Create new attribute item
331    AttributeItem Item = {
332      AttributeItem::NumericAttribute,
333      Attribute,
334      Value,
335      StringRef("")
336    };
337    Contents.push_back(Item);
338  }
339
340  void setAttributeItem(unsigned Attribute, StringRef Value,
341                        bool OverwriteExisting) {
342    // Look for existing attribute item
343    if (AttributeItem *Item = getAttributeItem(Attribute)) {
344      if (!OverwriteExisting)
345        return;
346      Item->Type = AttributeItem::TextAttribute;
347      Item->StringValue = Value;
348      return;
349    }
350
351    // Create new attribute item
352    AttributeItem Item = {
353      AttributeItem::TextAttribute,
354      Attribute,
355      0,
356      Value
357    };
358    Contents.push_back(Item);
359  }
360
361  void setAttributeItems(unsigned Attribute, unsigned IntValue,
362                         StringRef StringValue, bool OverwriteExisting) {
363    // Look for existing attribute item
364    if (AttributeItem *Item = getAttributeItem(Attribute)) {
365      if (!OverwriteExisting)
366        return;
367      Item->Type = AttributeItem::NumericAndTextAttributes;
368      Item->IntValue = IntValue;
369      Item->StringValue = StringValue;
370      return;
371    }
372
373    // Create new attribute item
374    AttributeItem Item = {
375      AttributeItem::NumericAndTextAttributes,
376      Attribute,
377      IntValue,
378      StringValue
379    };
380    Contents.push_back(Item);
381  }
382
383  void emitArchDefaultAttributes();
384  void emitFPUDefaultAttributes();
385
386  ARMELFStreamer &getStreamer();
387
388  void emitFnStart() override;
389  void emitFnEnd() override;
390  void emitCantUnwind() override;
391  void emitPersonality(const MCSymbol *Personality) override;
392  void emitPersonalityIndex(unsigned Index) override;
393  void emitHandlerData() override;
394  void emitSetFP(unsigned FpReg, unsigned SpReg, int64_t Offset = 0) override;
395  void emitMovSP(unsigned Reg, int64_t Offset = 0) override;
396  void emitPad(int64_t Offset) override;
397  void emitRegSave(const SmallVectorImpl<unsigned> &RegList,
398                   bool isVector) override;
399  void emitUnwindRaw(int64_t Offset,
400                     const SmallVectorImpl<uint8_t> &Opcodes) override;
401
402  void switchVendor(StringRef Vendor) override;
403  void emitAttribute(unsigned Attribute, unsigned Value) override;
404  void emitTextAttribute(unsigned Attribute, StringRef String) override;
405  void emitIntTextAttribute(unsigned Attribute, unsigned IntValue,
406                            StringRef StringValue) override;
407  void emitArch(ARM::ArchKind Arch) override;
408  void emitObjectArch(ARM::ArchKind Arch) override;
409  void emitFPU(unsigned FPU) override;
410  void emitInst(uint32_t Inst, char Suffix = '\0') override;
411  void finishAttributeSection() override;
412  void emitLabel(MCSymbol *Symbol) override;
413
414  void AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *SRE) override;
415  void emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) override;
416
417  size_t calculateContentSize() const;
418
419  // Reset state between object emissions
420  void reset() override;
421
422public:
423  ARMTargetELFStreamer(MCStreamer &S)
424    : ARMTargetStreamer(S), CurrentVendor("aeabi") {}
425};
426
427/// Extend the generic ELFStreamer class so that it can emit mapping symbols at
428/// the appropriate points in the object files. These symbols are defined in the
429/// ARM ELF ABI: infocenter.arm.com/help/topic/com.arm.../IHI0044D_aaelf.pdf.
430///
431/// In brief: $a, $t or $d should be emitted at the start of each contiguous
432/// region of ARM code, Thumb code or data in a section. In practice, this
433/// emission does not rely on explicit assembler directives but on inherent
434/// properties of the directives doing the emission (e.g. ".byte" is data, "add
435/// r0, r0, r0" an instruction).
436///
437/// As a result this system is orthogonal to the DataRegion infrastructure used
438/// by MachO. Beware!
439class ARMELFStreamer : public MCELFStreamer {
440public:
441  friend class ARMTargetELFStreamer;
442
443  ARMELFStreamer(MCContext &Context, std::unique_ptr<MCAsmBackend> TAB,
444                 std::unique_ptr<MCObjectWriter> OW, std::unique_ptr<MCCodeEmitter> Emitter,
445                 bool IsThumb)
446      : MCELFStreamer(Context, std::move(TAB), std::move(OW), std::move(Emitter)),
447        IsThumb(IsThumb) {
448    EHReset();
449  }
450
451  ~ARMELFStreamer() override = default;
452
453  void FinishImpl() override;
454
455  // ARM exception handling directives
456  void emitFnStart();
457  void emitFnEnd();
458  void emitCantUnwind();
459  void emitPersonality(const MCSymbol *Per);
460  void emitPersonalityIndex(unsigned index);
461  void emitHandlerData();
462  void emitSetFP(unsigned NewFpReg, unsigned NewSpReg, int64_t Offset = 0);
463  void emitMovSP(unsigned Reg, int64_t Offset = 0);
464  void emitPad(int64_t Offset);
465  void emitRegSave(const SmallVectorImpl<unsigned> &RegList, bool isVector);
466  void emitUnwindRaw(int64_t Offset, const SmallVectorImpl<uint8_t> &Opcodes);
467  void emitFill(const MCExpr &NumBytes, uint64_t FillValue,
468                SMLoc Loc) override {
469    EmitDataMappingSymbol();
470    MCObjectStreamer::emitFill(NumBytes, FillValue, Loc);
471  }
472
473  void ChangeSection(MCSection *Section, const MCExpr *Subsection) override {
474    LastMappingSymbols[getCurrentSection().first] = std::move(LastEMSInfo);
475    MCELFStreamer::ChangeSection(Section, Subsection);
476    auto LastMappingSymbol = LastMappingSymbols.find(Section);
477    if (LastMappingSymbol != LastMappingSymbols.end()) {
478      LastEMSInfo = std::move(LastMappingSymbol->second);
479      return;
480    }
481    LastEMSInfo.reset(new ElfMappingSymbolInfo(SMLoc(), nullptr, 0));
482  }
483
484  /// This function is the one used to emit instruction data into the ELF
485  /// streamer. We override it to add the appropriate mapping symbol if
486  /// necessary.
487  void EmitInstruction(const MCInst &Inst,
488                       const MCSubtargetInfo &STI) override {
489    if (IsThumb)
490      EmitThumbMappingSymbol();
491    else
492      EmitARMMappingSymbol();
493
494    MCELFStreamer::EmitInstruction(Inst, STI);
495  }
496
497  void emitInst(uint32_t Inst, char Suffix) {
498    unsigned Size;
499    char Buffer[4];
500    const bool LittleEndian = getContext().getAsmInfo()->isLittleEndian();
501
502    switch (Suffix) {
503    case '\0':
504      Size = 4;
505
506      assert(!IsThumb);
507      EmitARMMappingSymbol();
508      for (unsigned II = 0, IE = Size; II != IE; II++) {
509        const unsigned I = LittleEndian ? (Size - II - 1) : II;
510        Buffer[Size - II - 1] = uint8_t(Inst >> I * CHAR_BIT);
511      }
512
513      break;
514    case 'n':
515    case 'w':
516      Size = (Suffix == 'n' ? 2 : 4);
517
518      assert(IsThumb);
519      EmitThumbMappingSymbol();
520      // Thumb wide instructions are emitted as a pair of 16-bit words of the
521      // appropriate endianness.
522      for (unsigned II = 0, IE = Size; II != IE; II = II + 2) {
523        const unsigned I0 = LittleEndian ? II + 0 : II + 1;
524        const unsigned I1 = LittleEndian ? II + 1 : II + 0;
525        Buffer[Size - II - 2] = uint8_t(Inst >> I0 * CHAR_BIT);
526        Buffer[Size - II - 1] = uint8_t(Inst >> I1 * CHAR_BIT);
527      }
528
529      break;
530    default:
531      llvm_unreachable("Invalid Suffix");
532    }
533
534    MCELFStreamer::EmitBytes(StringRef(Buffer, Size));
535  }
536
537  /// This is one of the functions used to emit data into an ELF section, so the
538  /// ARM streamer overrides it to add the appropriate mapping symbol ($d) if
539  /// necessary.
540  void EmitBytes(StringRef Data) override {
541    EmitDataMappingSymbol();
542    MCELFStreamer::EmitBytes(Data);
543  }
544
545  void FlushPendingMappingSymbol() {
546    if (!LastEMSInfo->hasInfo())
547      return;
548    ElfMappingSymbolInfo *EMS = LastEMSInfo.get();
549    EmitMappingSymbol("$d", EMS->Loc, EMS->F, EMS->Offset);
550    EMS->resetInfo();
551  }
552
553  /// This is one of the functions used to emit data into an ELF section, so the
554  /// ARM streamer overrides it to add the appropriate mapping symbol ($d) if
555  /// necessary.
556  void EmitValueImpl(const MCExpr *Value, unsigned Size, SMLoc Loc) override {
557    if (const MCSymbolRefExpr *SRE = dyn_cast_or_null<MCSymbolRefExpr>(Value)) {
558      if (SRE->getKind() == MCSymbolRefExpr::VK_ARM_SBREL && !(Size == 4)) {
559        getContext().reportError(Loc, "relocated expression must be 32-bit");
560        return;
561      }
562      getOrCreateDataFragment();
563    }
564
565    EmitDataMappingSymbol();
566    MCELFStreamer::EmitValueImpl(Value, Size, Loc);
567  }
568
569  void EmitAssemblerFlag(MCAssemblerFlag Flag) override {
570    MCELFStreamer::EmitAssemblerFlag(Flag);
571
572    switch (Flag) {
573    case MCAF_SyntaxUnified:
574      return; // no-op here.
575    case MCAF_Code16:
576      IsThumb = true;
577      return; // Change to Thumb mode
578    case MCAF_Code32:
579      IsThumb = false;
580      return; // Change to ARM mode
581    case MCAF_Code64:
582      return;
583    case MCAF_SubsectionsViaSymbols:
584      return;
585    }
586  }
587
588private:
589  enum ElfMappingSymbol {
590    EMS_None,
591    EMS_ARM,
592    EMS_Thumb,
593    EMS_Data
594  };
595
596  struct ElfMappingSymbolInfo {
597    explicit ElfMappingSymbolInfo(SMLoc Loc, MCFragment *F, uint64_t O)
598        : Loc(Loc), F(F), Offset(O), State(EMS_None) {}
599    void resetInfo() {
600      F = nullptr;
601      Offset = 0;
602    }
603    bool hasInfo() { return F != nullptr; }
604    SMLoc Loc;
605    MCFragment *F;
606    uint64_t Offset;
607    ElfMappingSymbol State;
608  };
609
610  void EmitDataMappingSymbol() {
611    if (LastEMSInfo->State == EMS_Data)
612      return;
613    else if (LastEMSInfo->State == EMS_None) {
614      // This is a tentative symbol, it won't really be emitted until it's
615      // actually needed.
616      ElfMappingSymbolInfo *EMS = LastEMSInfo.get();
617      auto *DF = dyn_cast_or_null<MCDataFragment>(getCurrentFragment());
618      if (!DF)
619        return;
620      EMS->Loc = SMLoc();
621      EMS->F = getCurrentFragment();
622      EMS->Offset = DF->getContents().size();
623      LastEMSInfo->State = EMS_Data;
624      return;
625    }
626    EmitMappingSymbol("$d");
627    LastEMSInfo->State = EMS_Data;
628  }
629
630  void EmitThumbMappingSymbol() {
631    if (LastEMSInfo->State == EMS_Thumb)
632      return;
633    FlushPendingMappingSymbol();
634    EmitMappingSymbol("$t");
635    LastEMSInfo->State = EMS_Thumb;
636  }
637
638  void EmitARMMappingSymbol() {
639    if (LastEMSInfo->State == EMS_ARM)
640      return;
641    FlushPendingMappingSymbol();
642    EmitMappingSymbol("$a");
643    LastEMSInfo->State = EMS_ARM;
644  }
645
646  void EmitMappingSymbol(StringRef Name) {
647    auto *Symbol = cast<MCSymbolELF>(getContext().getOrCreateSymbol(
648        Name + "." + Twine(MappingSymbolCounter++)));
649    EmitLabel(Symbol);
650
651    Symbol->setType(ELF::STT_NOTYPE);
652    Symbol->setBinding(ELF::STB_LOCAL);
653    Symbol->setExternal(false);
654  }
655
656  void EmitMappingSymbol(StringRef Name, SMLoc Loc, MCFragment *F,
657                         uint64_t Offset) {
658    auto *Symbol = cast<MCSymbolELF>(getContext().getOrCreateSymbol(
659        Name + "." + Twine(MappingSymbolCounter++)));
660    EmitLabel(Symbol, Loc, F);
661    Symbol->setType(ELF::STT_NOTYPE);
662    Symbol->setBinding(ELF::STB_LOCAL);
663    Symbol->setExternal(false);
664    Symbol->setOffset(Offset);
665  }
666
667  void EmitThumbFunc(MCSymbol *Func) override {
668    getAssembler().setIsThumbFunc(Func);
669    EmitSymbolAttribute(Func, MCSA_ELF_TypeFunction);
670  }
671
672  // Helper functions for ARM exception handling directives
673  void EHReset();
674
675  // Reset state between object emissions
676  void reset() override;
677
678  void EmitPersonalityFixup(StringRef Name);
679  void FlushPendingOffset();
680  void FlushUnwindOpcodes(bool NoHandlerData);
681
682  void SwitchToEHSection(StringRef Prefix, unsigned Type, unsigned Flags,
683                         SectionKind Kind, const MCSymbol &Fn);
684  void SwitchToExTabSection(const MCSymbol &FnStart);
685  void SwitchToExIdxSection(const MCSymbol &FnStart);
686
687  void EmitFixup(const MCExpr *Expr, MCFixupKind Kind);
688
689  bool IsThumb;
690  int64_t MappingSymbolCounter = 0;
691
692  DenseMap<const MCSection *, std::unique_ptr<ElfMappingSymbolInfo>>
693      LastMappingSymbols;
694
695  std::unique_ptr<ElfMappingSymbolInfo> LastEMSInfo;
696
697  // ARM Exception Handling Frame Information
698  MCSymbol *ExTab;
699  MCSymbol *FnStart;
700  const MCSymbol *Personality;
701  unsigned PersonalityIndex;
702  unsigned FPReg; // Frame pointer register
703  int64_t FPOffset; // Offset: (final frame pointer) - (initial $sp)
704  int64_t SPOffset; // Offset: (final $sp) - (initial $sp)
705  int64_t PendingOffset; // Offset: (final $sp) - (emitted $sp)
706  bool UsedFP;
707  bool CantUnwind;
708  SmallVector<uint8_t, 64> Opcodes;
709  UnwindOpcodeAssembler UnwindOpAsm;
710};
711
712} // end anonymous namespace
713
714ARMELFStreamer &ARMTargetELFStreamer::getStreamer() {
715  return static_cast<ARMELFStreamer &>(Streamer);
716}
717
718void ARMTargetELFStreamer::emitFnStart() { getStreamer().emitFnStart(); }
719void ARMTargetELFStreamer::emitFnEnd() { getStreamer().emitFnEnd(); }
720void ARMTargetELFStreamer::emitCantUnwind() { getStreamer().emitCantUnwind(); }
721
722void ARMTargetELFStreamer::emitPersonality(const MCSymbol *Personality) {
723  getStreamer().emitPersonality(Personality);
724}
725
726void ARMTargetELFStreamer::emitPersonalityIndex(unsigned Index) {
727  getStreamer().emitPersonalityIndex(Index);
728}
729
730void ARMTargetELFStreamer::emitHandlerData() {
731  getStreamer().emitHandlerData();
732}
733
734void ARMTargetELFStreamer::emitSetFP(unsigned FpReg, unsigned SpReg,
735                                     int64_t Offset) {
736  getStreamer().emitSetFP(FpReg, SpReg, Offset);
737}
738
739void ARMTargetELFStreamer::emitMovSP(unsigned Reg, int64_t Offset) {
740  getStreamer().emitMovSP(Reg, Offset);
741}
742
743void ARMTargetELFStreamer::emitPad(int64_t Offset) {
744  getStreamer().emitPad(Offset);
745}
746
747void ARMTargetELFStreamer::emitRegSave(const SmallVectorImpl<unsigned> &RegList,
748                                       bool isVector) {
749  getStreamer().emitRegSave(RegList, isVector);
750}
751
752void ARMTargetELFStreamer::emitUnwindRaw(int64_t Offset,
753                                      const SmallVectorImpl<uint8_t> &Opcodes) {
754  getStreamer().emitUnwindRaw(Offset, Opcodes);
755}
756
757void ARMTargetELFStreamer::switchVendor(StringRef Vendor) {
758  assert(!Vendor.empty() && "Vendor cannot be empty.");
759
760  if (CurrentVendor == Vendor)
761    return;
762
763  if (!CurrentVendor.empty())
764    finishAttributeSection();
765
766  assert(Contents.empty() &&
767         ".ARM.attributes should be flushed before changing vendor");
768  CurrentVendor = Vendor;
769
770}
771
772void ARMTargetELFStreamer::emitAttribute(unsigned Attribute, unsigned Value) {
773  setAttributeItem(Attribute, Value, /* OverwriteExisting= */ true);
774}
775
776void ARMTargetELFStreamer::emitTextAttribute(unsigned Attribute,
777                                             StringRef Value) {
778  setAttributeItem(Attribute, Value, /* OverwriteExisting= */ true);
779}
780
781void ARMTargetELFStreamer::emitIntTextAttribute(unsigned Attribute,
782                                                unsigned IntValue,
783                                                StringRef StringValue) {
784  setAttributeItems(Attribute, IntValue, StringValue,
785                    /* OverwriteExisting= */ true);
786}
787
788void ARMTargetELFStreamer::emitArch(ARM::ArchKind Value) {
789  Arch = Value;
790}
791
792void ARMTargetELFStreamer::emitObjectArch(ARM::ArchKind Value) {
793  EmittedArch = Value;
794}
795
796void ARMTargetELFStreamer::emitArchDefaultAttributes() {
797  using namespace ARMBuildAttrs;
798
799  setAttributeItem(CPU_name,
800                   ARM::getCPUAttr(Arch),
801                   false);
802
803  if (EmittedArch == ARM::ArchKind::INVALID)
804    setAttributeItem(CPU_arch,
805                     ARM::getArchAttr(Arch),
806                     false);
807  else
808    setAttributeItem(CPU_arch,
809                     ARM::getArchAttr(EmittedArch),
810                     false);
811
812  switch (Arch) {
813  case ARM::ArchKind::ARMV2:
814  case ARM::ArchKind::ARMV2A:
815  case ARM::ArchKind::ARMV3:
816  case ARM::ArchKind::ARMV3M:
817  case ARM::ArchKind::ARMV4:
818    setAttributeItem(ARM_ISA_use, Allowed, false);
819    break;
820
821  case ARM::ArchKind::ARMV4T:
822  case ARM::ArchKind::ARMV5T:
823  case ARM::ArchKind::ARMV5TE:
824  case ARM::ArchKind::ARMV6:
825    setAttributeItem(ARM_ISA_use, Allowed, false);
826    setAttributeItem(THUMB_ISA_use, Allowed, false);
827    break;
828
829  case ARM::ArchKind::ARMV6T2:
830    setAttributeItem(ARM_ISA_use, Allowed, false);
831    setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
832    break;
833
834  case ARM::ArchKind::ARMV6K:
835  case ARM::ArchKind::ARMV6KZ:
836    setAttributeItem(ARM_ISA_use, Allowed, false);
837    setAttributeItem(THUMB_ISA_use, Allowed, false);
838    setAttributeItem(Virtualization_use, AllowTZ, false);
839    break;
840
841  case ARM::ArchKind::ARMV6M:
842    setAttributeItem(THUMB_ISA_use, Allowed, false);
843    break;
844
845  case ARM::ArchKind::ARMV7A:
846    setAttributeItem(CPU_arch_profile, ApplicationProfile, false);
847    setAttributeItem(ARM_ISA_use, Allowed, false);
848    setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
849    break;
850
851  case ARM::ArchKind::ARMV7R:
852    setAttributeItem(CPU_arch_profile, RealTimeProfile, false);
853    setAttributeItem(ARM_ISA_use, Allowed, false);
854    setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
855    break;
856
857  case ARM::ArchKind::ARMV7EM:
858  case ARM::ArchKind::ARMV7M:
859    setAttributeItem(CPU_arch_profile, MicroControllerProfile, false);
860    setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
861    break;
862
863  case ARM::ArchKind::ARMV8A:
864  case ARM::ArchKind::ARMV8_1A:
865  case ARM::ArchKind::ARMV8_2A:
866  case ARM::ArchKind::ARMV8_3A:
867  case ARM::ArchKind::ARMV8_4A:
868  case ARM::ArchKind::ARMV8_5A:
869    setAttributeItem(CPU_arch_profile, ApplicationProfile, false);
870    setAttributeItem(ARM_ISA_use, Allowed, false);
871    setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
872    setAttributeItem(MPextension_use, Allowed, false);
873    setAttributeItem(Virtualization_use, AllowTZVirtualization, false);
874    break;
875
876  case ARM::ArchKind::ARMV8MBaseline:
877  case ARM::ArchKind::ARMV8MMainline:
878    setAttributeItem(THUMB_ISA_use, AllowThumbDerived, false);
879    setAttributeItem(CPU_arch_profile, MicroControllerProfile, false);
880    break;
881
882  case ARM::ArchKind::IWMMXT:
883    setAttributeItem(ARM_ISA_use, Allowed, false);
884    setAttributeItem(THUMB_ISA_use, Allowed, false);
885    setAttributeItem(WMMX_arch, AllowWMMXv1, false);
886    break;
887
888  case ARM::ArchKind::IWMMXT2:
889    setAttributeItem(ARM_ISA_use, Allowed, false);
890    setAttributeItem(THUMB_ISA_use, Allowed, false);
891    setAttributeItem(WMMX_arch, AllowWMMXv2, false);
892    break;
893
894  default:
895    report_fatal_error("Unknown Arch: " + Twine(ARM::getArchName(Arch)));
896    break;
897  }
898}
899
900void ARMTargetELFStreamer::emitFPU(unsigned Value) {
901  FPU = Value;
902}
903
904void ARMTargetELFStreamer::emitFPUDefaultAttributes() {
905  switch (FPU) {
906  case ARM::FK_VFP:
907  case ARM::FK_VFPV2:
908    setAttributeItem(ARMBuildAttrs::FP_arch,
909                     ARMBuildAttrs::AllowFPv2,
910                     /* OverwriteExisting= */ false);
911    break;
912
913  case ARM::FK_VFPV3:
914    setAttributeItem(ARMBuildAttrs::FP_arch,
915                     ARMBuildAttrs::AllowFPv3A,
916                     /* OverwriteExisting= */ false);
917    break;
918
919  case ARM::FK_VFPV3_FP16:
920    setAttributeItem(ARMBuildAttrs::FP_arch,
921                     ARMBuildAttrs::AllowFPv3A,
922                     /* OverwriteExisting= */ false);
923    setAttributeItem(ARMBuildAttrs::FP_HP_extension,
924                     ARMBuildAttrs::AllowHPFP,
925                     /* OverwriteExisting= */ false);
926    break;
927
928  case ARM::FK_VFPV3_D16:
929    setAttributeItem(ARMBuildAttrs::FP_arch,
930                     ARMBuildAttrs::AllowFPv3B,
931                     /* OverwriteExisting= */ false);
932    break;
933
934  case ARM::FK_VFPV3_D16_FP16:
935    setAttributeItem(ARMBuildAttrs::FP_arch,
936                     ARMBuildAttrs::AllowFPv3B,
937                     /* OverwriteExisting= */ false);
938    setAttributeItem(ARMBuildAttrs::FP_HP_extension,
939                     ARMBuildAttrs::AllowHPFP,
940                     /* OverwriteExisting= */ false);
941    break;
942
943  case ARM::FK_VFPV3XD:
944    setAttributeItem(ARMBuildAttrs::FP_arch,
945                     ARMBuildAttrs::AllowFPv3B,
946                     /* OverwriteExisting= */ false);
947    break;
948  case ARM::FK_VFPV3XD_FP16:
949    setAttributeItem(ARMBuildAttrs::FP_arch,
950                     ARMBuildAttrs::AllowFPv3B,
951                     /* OverwriteExisting= */ false);
952    setAttributeItem(ARMBuildAttrs::FP_HP_extension,
953                     ARMBuildAttrs::AllowHPFP,
954                     /* OverwriteExisting= */ false);
955    break;
956
957  case ARM::FK_VFPV4:
958    setAttributeItem(ARMBuildAttrs::FP_arch,
959                     ARMBuildAttrs::AllowFPv4A,
960                     /* OverwriteExisting= */ false);
961    break;
962
963  // ABI_HardFP_use is handled in ARMAsmPrinter, so _SP_D16 is treated the same
964  // as _D16 here.
965  case ARM::FK_FPV4_SP_D16:
966  case ARM::FK_VFPV4_D16:
967    setAttributeItem(ARMBuildAttrs::FP_arch,
968                     ARMBuildAttrs::AllowFPv4B,
969                     /* OverwriteExisting= */ false);
970    break;
971
972  case ARM::FK_FP_ARMV8:
973    setAttributeItem(ARMBuildAttrs::FP_arch,
974                     ARMBuildAttrs::AllowFPARMv8A,
975                     /* OverwriteExisting= */ false);
976    break;
977
978  // FPV5_D16 is identical to FP_ARMV8 except for the number of D registers, so
979  // uses the FP_ARMV8_D16 build attribute.
980  case ARM::FK_FPV5_SP_D16:
981  case ARM::FK_FPV5_D16:
982    setAttributeItem(ARMBuildAttrs::FP_arch,
983                     ARMBuildAttrs::AllowFPARMv8B,
984                     /* OverwriteExisting= */ false);
985    break;
986
987  case ARM::FK_NEON:
988    setAttributeItem(ARMBuildAttrs::FP_arch,
989                     ARMBuildAttrs::AllowFPv3A,
990                     /* OverwriteExisting= */ false);
991    setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
992                     ARMBuildAttrs::AllowNeon,
993                     /* OverwriteExisting= */ false);
994    break;
995
996  case ARM::FK_NEON_FP16:
997    setAttributeItem(ARMBuildAttrs::FP_arch,
998                     ARMBuildAttrs::AllowFPv3A,
999                     /* OverwriteExisting= */ false);
1000    setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
1001                     ARMBuildAttrs::AllowNeon,
1002                     /* OverwriteExisting= */ false);
1003    setAttributeItem(ARMBuildAttrs::FP_HP_extension,
1004                     ARMBuildAttrs::AllowHPFP,
1005                     /* OverwriteExisting= */ false);
1006    break;
1007
1008  case ARM::FK_NEON_VFPV4:
1009    setAttributeItem(ARMBuildAttrs::FP_arch,
1010                     ARMBuildAttrs::AllowFPv4A,
1011                     /* OverwriteExisting= */ false);
1012    setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
1013                     ARMBuildAttrs::AllowNeon2,
1014                     /* OverwriteExisting= */ false);
1015    break;
1016
1017  case ARM::FK_NEON_FP_ARMV8:
1018  case ARM::FK_CRYPTO_NEON_FP_ARMV8:
1019    setAttributeItem(ARMBuildAttrs::FP_arch,
1020                     ARMBuildAttrs::AllowFPARMv8A,
1021                     /* OverwriteExisting= */ false);
1022    // 'Advanced_SIMD_arch' must be emitted not here, but within
1023    // ARMAsmPrinter::emitAttributes(), depending on hasV8Ops() and hasV8_1a()
1024    break;
1025
1026  case ARM::FK_SOFTVFP:
1027  case ARM::FK_NONE:
1028    break;
1029
1030  default:
1031    report_fatal_error("Unknown FPU: " + Twine(FPU));
1032    break;
1033  }
1034}
1035
1036size_t ARMTargetELFStreamer::calculateContentSize() const {
1037  size_t Result = 0;
1038  for (size_t i = 0; i < Contents.size(); ++i) {
1039    AttributeItem item = Contents[i];
1040    switch (item.Type) {
1041    case AttributeItem::HiddenAttribute:
1042      break;
1043    case AttributeItem::NumericAttribute:
1044      Result += getULEB128Size(item.Tag);
1045      Result += getULEB128Size(item.IntValue);
1046      break;
1047    case AttributeItem::TextAttribute:
1048      Result += getULEB128Size(item.Tag);
1049      Result += item.StringValue.size() + 1; // string + '\0'
1050      break;
1051    case AttributeItem::NumericAndTextAttributes:
1052      Result += getULEB128Size(item.Tag);
1053      Result += getULEB128Size(item.IntValue);
1054      Result += item.StringValue.size() + 1; // string + '\0';
1055      break;
1056    }
1057  }
1058  return Result;
1059}
1060
1061void ARMTargetELFStreamer::finishAttributeSection() {
1062  // <format-version>
1063  // [ <section-length> "vendor-name"
1064  // [ <file-tag> <size> <attribute>*
1065  //   | <section-tag> <size> <section-number>* 0 <attribute>*
1066  //   | <symbol-tag> <size> <symbol-number>* 0 <attribute>*
1067  //   ]+
1068  // ]*
1069
1070  if (FPU != ARM::FK_INVALID)
1071    emitFPUDefaultAttributes();
1072
1073  if (Arch != ARM::ArchKind::INVALID)
1074    emitArchDefaultAttributes();
1075
1076  if (Contents.empty())
1077    return;
1078
1079  llvm::sort(Contents, AttributeItem::LessTag);
1080
1081  ARMELFStreamer &Streamer = getStreamer();
1082
1083  // Switch to .ARM.attributes section
1084  if (AttributeSection) {
1085    Streamer.SwitchSection(AttributeSection);
1086  } else {
1087    AttributeSection = Streamer.getContext().getELFSection(
1088        ".ARM.attributes", ELF::SHT_ARM_ATTRIBUTES, 0);
1089    Streamer.SwitchSection(AttributeSection);
1090
1091    // Format version
1092    Streamer.EmitIntValue(0x41, 1);
1093  }
1094
1095  // Vendor size + Vendor name + '\0'
1096  const size_t VendorHeaderSize = 4 + CurrentVendor.size() + 1;
1097
1098  // Tag + Tag Size
1099  const size_t TagHeaderSize = 1 + 4;
1100
1101  const size_t ContentsSize = calculateContentSize();
1102
1103  Streamer.EmitIntValue(VendorHeaderSize + TagHeaderSize + ContentsSize, 4);
1104  Streamer.EmitBytes(CurrentVendor);
1105  Streamer.EmitIntValue(0, 1); // '\0'
1106
1107  Streamer.EmitIntValue(ARMBuildAttrs::File, 1);
1108  Streamer.EmitIntValue(TagHeaderSize + ContentsSize, 4);
1109
1110  // Size should have been accounted for already, now
1111  // emit each field as its type (ULEB or String)
1112  for (size_t i = 0; i < Contents.size(); ++i) {
1113    AttributeItem item = Contents[i];
1114    Streamer.EmitULEB128IntValue(item.Tag);
1115    switch (item.Type) {
1116    default: llvm_unreachable("Invalid attribute type");
1117    case AttributeItem::NumericAttribute:
1118      Streamer.EmitULEB128IntValue(item.IntValue);
1119      break;
1120    case AttributeItem::TextAttribute:
1121      Streamer.EmitBytes(item.StringValue);
1122      Streamer.EmitIntValue(0, 1); // '\0'
1123      break;
1124    case AttributeItem::NumericAndTextAttributes:
1125      Streamer.EmitULEB128IntValue(item.IntValue);
1126      Streamer.EmitBytes(item.StringValue);
1127      Streamer.EmitIntValue(0, 1); // '\0'
1128      break;
1129    }
1130  }
1131
1132  Contents.clear();
1133  FPU = ARM::FK_INVALID;
1134}
1135
1136void ARMTargetELFStreamer::emitLabel(MCSymbol *Symbol) {
1137  ARMELFStreamer &Streamer = getStreamer();
1138  if (!Streamer.IsThumb)
1139    return;
1140
1141  Streamer.getAssembler().registerSymbol(*Symbol);
1142  unsigned Type = cast<MCSymbolELF>(Symbol)->getType();
1143  if (Type == ELF::STT_FUNC || Type == ELF::STT_GNU_IFUNC)
1144    Streamer.EmitThumbFunc(Symbol);
1145}
1146
1147void
1148ARMTargetELFStreamer::AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *S) {
1149  getStreamer().EmitFixup(S, FK_Data_4);
1150}
1151
1152void ARMTargetELFStreamer::emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) {
1153  if (const MCSymbolRefExpr *SRE = dyn_cast<MCSymbolRefExpr>(Value)) {
1154    const MCSymbol &Sym = SRE->getSymbol();
1155    if (!Sym.isDefined()) {
1156      getStreamer().EmitAssignment(Symbol, Value);
1157      return;
1158    }
1159  }
1160
1161  getStreamer().EmitThumbFunc(Symbol);
1162  getStreamer().EmitAssignment(Symbol, Value);
1163}
1164
1165void ARMTargetELFStreamer::emitInst(uint32_t Inst, char Suffix) {
1166  getStreamer().emitInst(Inst, Suffix);
1167}
1168
1169void ARMTargetELFStreamer::reset() { AttributeSection = nullptr; }
1170
1171void ARMELFStreamer::FinishImpl() {
1172  MCTargetStreamer &TS = *getTargetStreamer();
1173  ARMTargetStreamer &ATS = static_cast<ARMTargetStreamer &>(TS);
1174  ATS.finishAttributeSection();
1175
1176  MCELFStreamer::FinishImpl();
1177}
1178
1179void ARMELFStreamer::reset() {
1180  MCTargetStreamer &TS = *getTargetStreamer();
1181  ARMTargetStreamer &ATS = static_cast<ARMTargetStreamer &>(TS);
1182  ATS.reset();
1183  MappingSymbolCounter = 0;
1184  MCELFStreamer::reset();
1185  LastMappingSymbols.clear();
1186  LastEMSInfo.reset();
1187  // MCELFStreamer clear's the assembler's e_flags. However, for
1188  // arm we manually set the ABI version on streamer creation, so
1189  // do the same here
1190  getAssembler().setELFHeaderEFlags(ELF::EF_ARM_EABI_VER5);
1191}
1192
1193inline void ARMELFStreamer::SwitchToEHSection(StringRef Prefix,
1194                                              unsigned Type,
1195                                              unsigned Flags,
1196                                              SectionKind Kind,
1197                                              const MCSymbol &Fn) {
1198  const MCSectionELF &FnSection =
1199    static_cast<const MCSectionELF &>(Fn.getSection());
1200
1201  // Create the name for new section
1202  StringRef FnSecName(FnSection.getSectionName());
1203  SmallString<128> EHSecName(Prefix);
1204  if (FnSecName != ".text") {
1205    EHSecName += FnSecName;
1206  }
1207
1208  // Get .ARM.extab or .ARM.exidx section
1209  const MCSymbolELF *Group = FnSection.getGroup();
1210  if (Group)
1211    Flags |= ELF::SHF_GROUP;
1212  MCSectionELF *EHSection = getContext().getELFSection(
1213      EHSecName, Type, Flags, 0, Group, FnSection.getUniqueID(),
1214      static_cast<const MCSymbolELF *>(&Fn));
1215
1216  assert(EHSection && "Failed to get the required EH section");
1217
1218  // Switch to .ARM.extab or .ARM.exidx section
1219  SwitchSection(EHSection);
1220  EmitCodeAlignment(4);
1221}
1222
1223inline void ARMELFStreamer::SwitchToExTabSection(const MCSymbol &FnStart) {
1224  SwitchToEHSection(".ARM.extab", ELF::SHT_PROGBITS, ELF::SHF_ALLOC,
1225                    SectionKind::getData(), FnStart);
1226}
1227
1228inline void ARMELFStreamer::SwitchToExIdxSection(const MCSymbol &FnStart) {
1229  SwitchToEHSection(".ARM.exidx", ELF::SHT_ARM_EXIDX,
1230                    ELF::SHF_ALLOC | ELF::SHF_LINK_ORDER,
1231                    SectionKind::getData(), FnStart);
1232}
1233
1234void ARMELFStreamer::EmitFixup(const MCExpr *Expr, MCFixupKind Kind) {
1235  MCDataFragment *Frag = getOrCreateDataFragment();
1236  Frag->getFixups().push_back(MCFixup::create(Frag->getContents().size(), Expr,
1237                                              Kind));
1238}
1239
1240void ARMELFStreamer::EHReset() {
1241  ExTab = nullptr;
1242  FnStart = nullptr;
1243  Personality = nullptr;
1244  PersonalityIndex = ARM::EHABI::NUM_PERSONALITY_INDEX;
1245  FPReg = ARM::SP;
1246  FPOffset = 0;
1247  SPOffset = 0;
1248  PendingOffset = 0;
1249  UsedFP = false;
1250  CantUnwind = false;
1251
1252  Opcodes.clear();
1253  UnwindOpAsm.Reset();
1254}
1255
1256void ARMELFStreamer::emitFnStart() {
1257  assert(FnStart == nullptr);
1258  FnStart = getContext().createTempSymbol();
1259  EmitLabel(FnStart);
1260}
1261
1262void ARMELFStreamer::emitFnEnd() {
1263  assert(FnStart && ".fnstart must precedes .fnend");
1264
1265  // Emit unwind opcodes if there is no .handlerdata directive
1266  if (!ExTab && !CantUnwind)
1267    FlushUnwindOpcodes(true);
1268
1269  // Emit the exception index table entry
1270  SwitchToExIdxSection(*FnStart);
1271
1272  if (PersonalityIndex < ARM::EHABI::NUM_PERSONALITY_INDEX)
1273    EmitPersonalityFixup(GetAEABIUnwindPersonalityName(PersonalityIndex));
1274
1275  const MCSymbolRefExpr *FnStartRef =
1276    MCSymbolRefExpr::create(FnStart,
1277                            MCSymbolRefExpr::VK_ARM_PREL31,
1278                            getContext());
1279
1280  EmitValue(FnStartRef, 4);
1281
1282  if (CantUnwind) {
1283    EmitIntValue(ARM::EHABI::EXIDX_CANTUNWIND, 4);
1284  } else if (ExTab) {
1285    // Emit a reference to the unwind opcodes in the ".ARM.extab" section.
1286    const MCSymbolRefExpr *ExTabEntryRef =
1287      MCSymbolRefExpr::create(ExTab,
1288                              MCSymbolRefExpr::VK_ARM_PREL31,
1289                              getContext());
1290    EmitValue(ExTabEntryRef, 4);
1291  } else {
1292    // For the __aeabi_unwind_cpp_pr0, we have to emit the unwind opcodes in
1293    // the second word of exception index table entry.  The size of the unwind
1294    // opcodes should always be 4 bytes.
1295    assert(PersonalityIndex == ARM::EHABI::AEABI_UNWIND_CPP_PR0 &&
1296           "Compact model must use __aeabi_unwind_cpp_pr0 as personality");
1297    assert(Opcodes.size() == 4u &&
1298           "Unwind opcode size for __aeabi_unwind_cpp_pr0 must be equal to 4");
1299    uint64_t Intval = Opcodes[0] |
1300                      Opcodes[1] << 8 |
1301                      Opcodes[2] << 16 |
1302                      Opcodes[3] << 24;
1303    EmitIntValue(Intval, Opcodes.size());
1304  }
1305
1306  // Switch to the section containing FnStart
1307  SwitchSection(&FnStart->getSection());
1308
1309  // Clean exception handling frame information
1310  EHReset();
1311}
1312
1313void ARMELFStreamer::emitCantUnwind() { CantUnwind = true; }
1314
1315// Add the R_ARM_NONE fixup at the same position
1316void ARMELFStreamer::EmitPersonalityFixup(StringRef Name) {
1317  const MCSymbol *PersonalitySym = getContext().getOrCreateSymbol(Name);
1318
1319  const MCSymbolRefExpr *PersonalityRef = MCSymbolRefExpr::create(
1320      PersonalitySym, MCSymbolRefExpr::VK_ARM_NONE, getContext());
1321
1322  visitUsedExpr(*PersonalityRef);
1323  MCDataFragment *DF = getOrCreateDataFragment();
1324  DF->getFixups().push_back(MCFixup::create(DF->getContents().size(),
1325                                            PersonalityRef,
1326                                            MCFixup::getKindForSize(4, false)));
1327}
1328
1329void ARMELFStreamer::FlushPendingOffset() {
1330  if (PendingOffset != 0) {
1331    UnwindOpAsm.EmitSPOffset(-PendingOffset);
1332    PendingOffset = 0;
1333  }
1334}
1335
1336void ARMELFStreamer::FlushUnwindOpcodes(bool NoHandlerData) {
1337  // Emit the unwind opcode to restore $sp.
1338  if (UsedFP) {
1339    const MCRegisterInfo *MRI = getContext().getRegisterInfo();
1340    int64_t LastRegSaveSPOffset = SPOffset - PendingOffset;
1341    UnwindOpAsm.EmitSPOffset(LastRegSaveSPOffset - FPOffset);
1342    UnwindOpAsm.EmitSetSP(MRI->getEncodingValue(FPReg));
1343  } else {
1344    FlushPendingOffset();
1345  }
1346
1347  // Finalize the unwind opcode sequence
1348  UnwindOpAsm.Finalize(PersonalityIndex, Opcodes);
1349
1350  // For compact model 0, we have to emit the unwind opcodes in the .ARM.exidx
1351  // section.  Thus, we don't have to create an entry in the .ARM.extab
1352  // section.
1353  if (NoHandlerData && PersonalityIndex == ARM::EHABI::AEABI_UNWIND_CPP_PR0)
1354    return;
1355
1356  // Switch to .ARM.extab section.
1357  SwitchToExTabSection(*FnStart);
1358
1359  // Create .ARM.extab label for offset in .ARM.exidx
1360  assert(!ExTab);
1361  ExTab = getContext().createTempSymbol();
1362  EmitLabel(ExTab);
1363
1364  // Emit personality
1365  if (Personality) {
1366    const MCSymbolRefExpr *PersonalityRef =
1367      MCSymbolRefExpr::create(Personality,
1368                              MCSymbolRefExpr::VK_ARM_PREL31,
1369                              getContext());
1370
1371    EmitValue(PersonalityRef, 4);
1372  }
1373
1374  // Emit unwind opcodes
1375  assert((Opcodes.size() % 4) == 0 &&
1376         "Unwind opcode size for __aeabi_cpp_unwind_pr0 must be multiple of 4");
1377  for (unsigned I = 0; I != Opcodes.size(); I += 4) {
1378    uint64_t Intval = Opcodes[I] |
1379                      Opcodes[I + 1] << 8 |
1380                      Opcodes[I + 2] << 16 |
1381                      Opcodes[I + 3] << 24;
1382    EmitIntValue(Intval, 4);
1383  }
1384
1385  // According to ARM EHABI section 9.2, if the __aeabi_unwind_cpp_pr1() or
1386  // __aeabi_unwind_cpp_pr2() is used, then the handler data must be emitted
1387  // after the unwind opcodes.  The handler data consists of several 32-bit
1388  // words, and should be terminated by zero.
1389  //
1390  // In case that the .handlerdata directive is not specified by the
1391  // programmer, we should emit zero to terminate the handler data.
1392  if (NoHandlerData && !Personality)
1393    EmitIntValue(0, 4);
1394}
1395
1396void ARMELFStreamer::emitHandlerData() { FlushUnwindOpcodes(false); }
1397
1398void ARMELFStreamer::emitPersonality(const MCSymbol *Per) {
1399  Personality = Per;
1400  UnwindOpAsm.setPersonality(Per);
1401}
1402
1403void ARMELFStreamer::emitPersonalityIndex(unsigned Index) {
1404  assert(Index < ARM::EHABI::NUM_PERSONALITY_INDEX && "invalid index");
1405  PersonalityIndex = Index;
1406}
1407
1408void ARMELFStreamer::emitSetFP(unsigned NewFPReg, unsigned NewSPReg,
1409                               int64_t Offset) {
1410  assert((NewSPReg == ARM::SP || NewSPReg == FPReg) &&
1411         "the operand of .setfp directive should be either $sp or $fp");
1412
1413  UsedFP = true;
1414  FPReg = NewFPReg;
1415
1416  if (NewSPReg == ARM::SP)
1417    FPOffset = SPOffset + Offset;
1418  else
1419    FPOffset += Offset;
1420}
1421
1422void ARMELFStreamer::emitMovSP(unsigned Reg, int64_t Offset) {
1423  assert((Reg != ARM::SP && Reg != ARM::PC) &&
1424         "the operand of .movsp cannot be either sp or pc");
1425  assert(FPReg == ARM::SP && "current FP must be SP");
1426
1427  FlushPendingOffset();
1428
1429  FPReg = Reg;
1430  FPOffset = SPOffset + Offset;
1431
1432  const MCRegisterInfo *MRI = getContext().getRegisterInfo();
1433  UnwindOpAsm.EmitSetSP(MRI->getEncodingValue(FPReg));
1434}
1435
1436void ARMELFStreamer::emitPad(int64_t Offset) {
1437  // Track the change of the $sp offset
1438  SPOffset -= Offset;
1439
1440  // To squash multiple .pad directives, we should delay the unwind opcode
1441  // until the .save, .vsave, .handlerdata, or .fnend directives.
1442  PendingOffset -= Offset;
1443}
1444
1445void ARMELFStreamer::emitRegSave(const SmallVectorImpl<unsigned> &RegList,
1446                                 bool IsVector) {
1447  // Collect the registers in the register list
1448  unsigned Count = 0;
1449  uint32_t Mask = 0;
1450  const MCRegisterInfo *MRI = getContext().getRegisterInfo();
1451  for (size_t i = 0; i < RegList.size(); ++i) {
1452    unsigned Reg = MRI->getEncodingValue(RegList[i]);
1453    assert(Reg < (IsVector ? 32U : 16U) && "Register out of range");
1454    unsigned Bit = (1u << Reg);
1455    if ((Mask & Bit) == 0) {
1456      Mask |= Bit;
1457      ++Count;
1458    }
1459  }
1460
1461  // Track the change the $sp offset: For the .save directive, the
1462  // corresponding push instruction will decrease the $sp by (4 * Count).
1463  // For the .vsave directive, the corresponding vpush instruction will
1464  // decrease $sp by (8 * Count).
1465  SPOffset -= Count * (IsVector ? 8 : 4);
1466
1467  // Emit the opcode
1468  FlushPendingOffset();
1469  if (IsVector)
1470    UnwindOpAsm.EmitVFPRegSave(Mask);
1471  else
1472    UnwindOpAsm.EmitRegSave(Mask);
1473}
1474
1475void ARMELFStreamer::emitUnwindRaw(int64_t Offset,
1476                                   const SmallVectorImpl<uint8_t> &Opcodes) {
1477  FlushPendingOffset();
1478  SPOffset = SPOffset - Offset;
1479  UnwindOpAsm.EmitRaw(Opcodes);
1480}
1481
1482namespace llvm {
1483
1484MCTargetStreamer *createARMTargetAsmStreamer(MCStreamer &S,
1485                                             formatted_raw_ostream &OS,
1486                                             MCInstPrinter *InstPrint,
1487                                             bool isVerboseAsm) {
1488  return new ARMTargetAsmStreamer(S, OS, *InstPrint, isVerboseAsm);
1489}
1490
1491MCTargetStreamer *createARMNullTargetStreamer(MCStreamer &S) {
1492  return new ARMTargetStreamer(S);
1493}
1494
1495MCTargetStreamer *createARMObjectTargetStreamer(MCStreamer &S,
1496                                                const MCSubtargetInfo &STI) {
1497  const Triple &TT = STI.getTargetTriple();
1498  if (TT.isOSBinFormatELF())
1499    return new ARMTargetELFStreamer(S);
1500  return new ARMTargetStreamer(S);
1501}
1502
1503MCELFStreamer *createARMELFStreamer(MCContext &Context,
1504                                    std::unique_ptr<MCAsmBackend> TAB,
1505                                    std::unique_ptr<MCObjectWriter> OW,
1506                                    std::unique_ptr<MCCodeEmitter> Emitter,
1507                                    bool RelaxAll, bool IsThumb) {
1508  ARMELFStreamer *S = new ARMELFStreamer(Context, std::move(TAB), std::move(OW),
1509                                         std::move(Emitter), IsThumb);
1510  // FIXME: This should eventually end up somewhere else where more
1511  // intelligent flag decisions can be made. For now we are just maintaining
1512  // the status quo for ARM and setting EF_ARM_EABI_VER5 as the default.
1513  S->getAssembler().setELFHeaderEFlags(ELF::EF_ARM_EABI_VER5);
1514
1515  if (RelaxAll)
1516    S->getAssembler().setRelaxAll(true);
1517  return S;
1518}
1519
1520} // end namespace llvm
1521