ARMELFStreamer.cpp revision 344779 
1//===- lib/MC/ARMELFStreamer.cpp - ELF Object Output for ARM --------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file assembles .s files and emits ARM ELF .o object files. Different
11// from generic ELF streamer in emitting mapping symbols ($a, $t and $d) to
12// delimit regions of data and code.
13//
14//===----------------------------------------------------------------------===//
15
16#include "ARMRegisterInfo.h"
17#include "ARMUnwindOpAsm.h"
18#include "llvm/ADT/DenseMap.h"
19#include "llvm/ADT/SmallString.h"
20#include "llvm/ADT/SmallVector.h"
21#include "llvm/ADT/StringRef.h"
22#include "llvm/ADT/Triple.h"
23#include "llvm/ADT/Twine.h"
24#include "llvm/BinaryFormat/ELF.h"
25#include "llvm/MC/MCAsmBackend.h"
26#include "llvm/MC/MCAsmInfo.h"
27#include "llvm/MC/MCAssembler.h"
28#include "llvm/MC/MCCodeEmitter.h"
29#include "llvm/MC/MCContext.h"
30#include "llvm/MC/MCELFStreamer.h"
31#include "llvm/MC/MCExpr.h"
32#include "llvm/MC/MCFixup.h"
33#include "llvm/MC/MCFragment.h"
34#include "llvm/MC/MCInst.h"
35#include "llvm/MC/MCInstPrinter.h"
36#include "llvm/MC/MCObjectWriter.h"
37#include "llvm/MC/MCRegisterInfo.h"
38#include "llvm/MC/MCSection.h"
39#include "llvm/MC/MCSectionELF.h"
40#include "llvm/MC/MCStreamer.h"
41#include "llvm/MC/MCSubtargetInfo.h"
42#include "llvm/MC/MCSymbol.h"
43#include "llvm/MC/MCSymbolELF.h"
44#include "llvm/MC/SectionKind.h"
45#include "llvm/Support/ARMBuildAttributes.h"
46#include "llvm/Support/ARMEHABI.h"
47#include "llvm/Support/Casting.h"
48#include "llvm/Support/ErrorHandling.h"
49#include "llvm/Support/FormattedStream.h"
50#include "llvm/Support/LEB128.h"
51#include "llvm/Support/TargetParser.h"
52#include "llvm/Support/raw_ostream.h"
53#include <algorithm>
54#include <cassert>
55#include <climits>
56#include <cstddef>
57#include <cstdint>
58#include <string>
59
60using namespace llvm;
61
62static std::string GetAEABIUnwindPersonalityName(unsigned Index) {
63  assert(Index < ARM::EHABI::NUM_PERSONALITY_INDEX &&
64         "Invalid personality index");
65  return (Twine("__aeabi_unwind_cpp_pr") + Twine(Index)).str();
66}
67
68namespace {
69
70class ARMELFStreamer;
71
72class ARMTargetAsmStreamer : public ARMTargetStreamer {
73  formatted_raw_ostream &OS;
74  MCInstPrinter &InstPrinter;
75  bool IsVerboseAsm;
76
77  void emitFnStart() override;
78  void emitFnEnd() override;
79  void emitCantUnwind() override;
80  void emitPersonality(const MCSymbol *Personality) override;
81  void emitPersonalityIndex(unsigned Index) override;
82  void emitHandlerData() override;
83  void emitSetFP(unsigned FpReg, unsigned SpReg, int64_t Offset = 0) override;
84  void emitMovSP(unsigned Reg, int64_t Offset = 0) override;
85  void emitPad(int64_t Offset) override;
86  void emitRegSave(const SmallVectorImpl<unsigned> &RegList,
87                   bool isVector) override;
88  void emitUnwindRaw(int64_t Offset,
89                     const SmallVectorImpl<uint8_t> &Opcodes) override;
90
91  void switchVendor(StringRef Vendor) override;
92  void emitAttribute(unsigned Attribute, unsigned Value) override;
93  void emitTextAttribute(unsigned Attribute, StringRef String) override;
94  void emitIntTextAttribute(unsigned Attribute, unsigned IntValue,
95                            StringRef StringValue) override;
96  void emitArch(ARM::ArchKind Arch) override;
97  void emitArchExtension(unsigned ArchExt) override;
98  void emitObjectArch(ARM::ArchKind Arch) override;
99  void emitFPU(unsigned FPU) override;
100  void emitInst(uint32_t Inst, char Suffix = '\0') override;
101  void finishAttributeSection() override;
102
103  void AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *SRE) override;
104  void emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) override;
105
106public:
107  ARMTargetAsmStreamer(MCStreamer &S, formatted_raw_ostream &OS,
108                       MCInstPrinter &InstPrinter, bool VerboseAsm);
109};
110
111ARMTargetAsmStreamer::ARMTargetAsmStreamer(MCStreamer &S,
112                                           formatted_raw_ostream &OS,
113                                           MCInstPrinter &InstPrinter,
114                                           bool VerboseAsm)
115    : ARMTargetStreamer(S), OS(OS), InstPrinter(InstPrinter),
116      IsVerboseAsm(VerboseAsm) {}
117
118void ARMTargetAsmStreamer::emitFnStart() { OS << "\t.fnstart\n"; }
119void ARMTargetAsmStreamer::emitFnEnd() { OS << "\t.fnend\n"; }
120void ARMTargetAsmStreamer::emitCantUnwind() { OS << "\t.cantunwind\n"; }
121
122void ARMTargetAsmStreamer::emitPersonality(const MCSymbol *Personality) {
123  OS << "\t.personality " << Personality->getName() << '\n';
124}
125
126void ARMTargetAsmStreamer::emitPersonalityIndex(unsigned Index) {
127  OS << "\t.personalityindex " << Index << '\n';
128}
129
130void ARMTargetAsmStreamer::emitHandlerData() { OS << "\t.handlerdata\n"; }
131
132void ARMTargetAsmStreamer::emitSetFP(unsigned FpReg, unsigned SpReg,
133                                     int64_t Offset) {
134  OS << "\t.setfp\t";
135  InstPrinter.printRegName(OS, FpReg);
136  OS << ", ";
137  InstPrinter.printRegName(OS, SpReg);
138  if (Offset)
139    OS << ", #" << Offset;
140  OS << '\n';
141}
142
143void ARMTargetAsmStreamer::emitMovSP(unsigned Reg, int64_t Offset) {
144  assert((Reg != ARM::SP && Reg != ARM::PC) &&
145         "the operand of .movsp cannot be either sp or pc");
146
147  OS << "\t.movsp\t";
148  InstPrinter.printRegName(OS, Reg);
149  if (Offset)
150    OS << ", #" << Offset;
151  OS << '\n';
152}
153
154void ARMTargetAsmStreamer::emitPad(int64_t Offset) {
155  OS << "\t.pad\t#" << Offset << '\n';
156}
157
158void ARMTargetAsmStreamer::emitRegSave(const SmallVectorImpl<unsigned> &RegList,
159                                       bool isVector) {
160  assert(RegList.size() && "RegList should not be empty");
161  if (isVector)
162    OS << "\t.vsave\t{";
163  else
164    OS << "\t.save\t{";
165
166  InstPrinter.printRegName(OS, RegList[0]);
167
168  for (unsigned i = 1, e = RegList.size(); i != e; ++i) {
169    OS << ", ";
170    InstPrinter.printRegName(OS, RegList[i]);
171  }
172
173  OS << "}\n";
174}
175
176void ARMTargetAsmStreamer::switchVendor(StringRef Vendor) {}
177
178void ARMTargetAsmStreamer::emitAttribute(unsigned Attribute, unsigned Value) {
179  OS << "\t.eabi_attribute\t" << Attribute << ", " << Twine(Value);
180  if (IsVerboseAsm) {
181    StringRef Name = ARMBuildAttrs::AttrTypeAsString(Attribute);
182    if (!Name.empty())
183      OS << "\t@ " << Name;
184  }
185  OS << "\n";
186}
187
188void ARMTargetAsmStreamer::emitTextAttribute(unsigned Attribute,
189                                             StringRef String) {
190  switch (Attribute) {
191  case ARMBuildAttrs::CPU_name:
192    OS << "\t.cpu\t" << String.lower();
193    break;
194  default:
195    OS << "\t.eabi_attribute\t" << Attribute << ", \"" << String << "\"";
196    if (IsVerboseAsm) {
197      StringRef Name = ARMBuildAttrs::AttrTypeAsString(Attribute);
198      if (!Name.empty())
199        OS << "\t@ " << Name;
200    }
201    break;
202  }
203  OS << "\n";
204}
205
206void ARMTargetAsmStreamer::emitIntTextAttribute(unsigned Attribute,
207                                                unsigned IntValue,
208                                                StringRef StringValue) {
209  switch (Attribute) {
210  default: llvm_unreachable("unsupported multi-value attribute in asm mode");
211  case ARMBuildAttrs::compatibility:
212    OS << "\t.eabi_attribute\t" << Attribute << ", " << IntValue;
213    if (!StringValue.empty())
214      OS << ", \"" << StringValue << "\"";
215    if (IsVerboseAsm)
216      OS << "\t@ " << ARMBuildAttrs::AttrTypeAsString(Attribute);
217    break;
218  }
219  OS << "\n";
220}
221
222void ARMTargetAsmStreamer::emitArch(ARM::ArchKind Arch) {
223  OS << "\t.arch\t" << ARM::getArchName(Arch) << "\n";
224}
225
226void ARMTargetAsmStreamer::emitArchExtension(unsigned ArchExt) {
227  OS << "\t.arch_extension\t" << ARM::getArchExtName(ArchExt) << "\n";
228}
229
230void ARMTargetAsmStreamer::emitObjectArch(ARM::ArchKind Arch) {
231  OS << "\t.object_arch\t" << ARM::getArchName(Arch) << '\n';
232}
233
234void ARMTargetAsmStreamer::emitFPU(unsigned FPU) {
235  OS << "\t.fpu\t" << ARM::getFPUName(FPU) << "\n";
236}
237
238void ARMTargetAsmStreamer::finishAttributeSection() {}
239
240void
241ARMTargetAsmStreamer::AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *S) {
242  OS << "\t.tlsdescseq\t" << S->getSymbol().getName();
243}
244
245void ARMTargetAsmStreamer::emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) {
246  const MCAsmInfo *MAI = Streamer.getContext().getAsmInfo();
247
248  OS << "\t.thumb_set\t";
249  Symbol->print(OS, MAI);
250  OS << ", ";
251  Value->print(OS, MAI);
252  OS << '\n';
253}
254
255void ARMTargetAsmStreamer::emitInst(uint32_t Inst, char Suffix) {
256  OS << "\t.inst";
257  if (Suffix)
258    OS << "." << Suffix;
259  OS << "\t0x" << Twine::utohexstr(Inst) << "\n";
260}
261
262void ARMTargetAsmStreamer::emitUnwindRaw(int64_t Offset,
263                                      const SmallVectorImpl<uint8_t> &Opcodes) {
264  OS << "\t.unwind_raw " << Offset;
265  for (SmallVectorImpl<uint8_t>::const_iterator OCI = Opcodes.begin(),
266                                                OCE = Opcodes.end();
267       OCI != OCE; ++OCI)
268    OS << ", 0x" << Twine::utohexstr(*OCI);
269  OS << '\n';
270}
271
272class ARMTargetELFStreamer : public ARMTargetStreamer {
273private:
274  // This structure holds all attributes, accounting for
275  // their string/numeric value, so we can later emit them
276  // in declaration order, keeping all in the same vector
277  struct AttributeItem {
278    enum {
279      HiddenAttribute = 0,
280      NumericAttribute,
281      TextAttribute,
282      NumericAndTextAttributes
283    } Type;
284    unsigned Tag;
285    unsigned IntValue;
286    std::string StringValue;
287
288    static bool LessTag(const AttributeItem &LHS, const AttributeItem &RHS) {
289      // The conformance tag must be emitted first when serialised
290      // into an object file. Specifically, the addenda to the ARM ABI
291      // states that (2.3.7.4):
292      //
293      // "To simplify recognition by consumers in the common case of
294      // claiming conformity for the whole file, this tag should be
295      // emitted first in a file-scope sub-subsection of the first
296      // public subsection of the attributes section."
297      //
298      // So it is special-cased in this comparison predicate when the
299      // attributes are sorted in finishAttributeSection().
300      return (RHS.Tag != ARMBuildAttrs::conformance) &&
301             ((LHS.Tag == ARMBuildAttrs::conformance) || (LHS.Tag < RHS.Tag));
302    }
303  };
304
305  StringRef CurrentVendor;
306  unsigned FPU = ARM::FK_INVALID;
307  ARM::ArchKind Arch = ARM::ArchKind::INVALID;
308  ARM::ArchKind EmittedArch = ARM::ArchKind::INVALID;
309  SmallVector<AttributeItem, 64> Contents;
310
311  MCSection *AttributeSection = nullptr;
312
313  AttributeItem *getAttributeItem(unsigned Attribute) {
314    for (size_t i = 0; i < Contents.size(); ++i)
315      if (Contents[i].Tag == Attribute)
316        return &Contents[i];
317    return nullptr;
318  }
319
320  void setAttributeItem(unsigned Attribute, unsigned Value,
321                        bool OverwriteExisting) {
322    // Look for existing attribute item
323    if (AttributeItem *Item = getAttributeItem(Attribute)) {
324      if (!OverwriteExisting)
325        return;
326      Item->Type = AttributeItem::NumericAttribute;
327      Item->IntValue = Value;
328      return;
329    }
330
331    // Create new attribute item
332    AttributeItem Item = {
333      AttributeItem::NumericAttribute,
334      Attribute,
335      Value,
336      StringRef("")
337    };
338    Contents.push_back(Item);
339  }
340
341  void setAttributeItem(unsigned Attribute, StringRef Value,
342                        bool OverwriteExisting) {
343    // Look for existing attribute item
344    if (AttributeItem *Item = getAttributeItem(Attribute)) {
345      if (!OverwriteExisting)
346        return;
347      Item->Type = AttributeItem::TextAttribute;
348      Item->StringValue = Value;
349      return;
350    }
351
352    // Create new attribute item
353    AttributeItem Item = {
354      AttributeItem::TextAttribute,
355      Attribute,
356      0,
357      Value
358    };
359    Contents.push_back(Item);
360  }
361
362  void setAttributeItems(unsigned Attribute, unsigned IntValue,
363                         StringRef StringValue, bool OverwriteExisting) {
364    // Look for existing attribute item
365    if (AttributeItem *Item = getAttributeItem(Attribute)) {
366      if (!OverwriteExisting)
367        return;
368      Item->Type = AttributeItem::NumericAndTextAttributes;
369      Item->IntValue = IntValue;
370      Item->StringValue = StringValue;
371      return;
372    }
373
374    // Create new attribute item
375    AttributeItem Item = {
376      AttributeItem::NumericAndTextAttributes,
377      Attribute,
378      IntValue,
379      StringValue
380    };
381    Contents.push_back(Item);
382  }
383
384  void emitArchDefaultAttributes();
385  void emitFPUDefaultAttributes();
386
387  ARMELFStreamer &getStreamer();
388
389  void emitFnStart() override;
390  void emitFnEnd() override;
391  void emitCantUnwind() override;
392  void emitPersonality(const MCSymbol *Personality) override;
393  void emitPersonalityIndex(unsigned Index) override;
394  void emitHandlerData() override;
395  void emitSetFP(unsigned FpReg, unsigned SpReg, int64_t Offset = 0) override;
396  void emitMovSP(unsigned Reg, int64_t Offset = 0) override;
397  void emitPad(int64_t Offset) override;
398  void emitRegSave(const SmallVectorImpl<unsigned> &RegList,
399                   bool isVector) override;
400  void emitUnwindRaw(int64_t Offset,
401                     const SmallVectorImpl<uint8_t> &Opcodes) override;
402
403  void switchVendor(StringRef Vendor) override;
404  void emitAttribute(unsigned Attribute, unsigned Value) override;
405  void emitTextAttribute(unsigned Attribute, StringRef String) override;
406  void emitIntTextAttribute(unsigned Attribute, unsigned IntValue,
407                            StringRef StringValue) override;
408  void emitArch(ARM::ArchKind Arch) override;
409  void emitObjectArch(ARM::ArchKind Arch) override;
410  void emitFPU(unsigned FPU) override;
411  void emitInst(uint32_t Inst, char Suffix = '\0') override;
412  void finishAttributeSection() override;
413  void emitLabel(MCSymbol *Symbol) override;
414
415  void AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *SRE) override;
416  void emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) override;
417
418  size_t calculateContentSize() const;
419
420  // Reset state between object emissions
421  void reset() override;
422
423public:
424  ARMTargetELFStreamer(MCStreamer &S)
425    : ARMTargetStreamer(S), CurrentVendor("aeabi") {}
426};
427
428/// Extend the generic ELFStreamer class so that it can emit mapping symbols at
429/// the appropriate points in the object files. These symbols are defined in the
430/// ARM ELF ABI: infocenter.arm.com/help/topic/com.arm.../IHI0044D_aaelf.pdf.
431///
432/// In brief: $a, $t or $d should be emitted at the start of each contiguous
433/// region of ARM code, Thumb code or data in a section. In practice, this
434/// emission does not rely on explicit assembler directives but on inherent
435/// properties of the directives doing the emission (e.g. ".byte" is data, "add
436/// r0, r0, r0" an instruction).
437///
438/// As a result this system is orthogonal to the DataRegion infrastructure used
439/// by MachO. Beware!
440class ARMELFStreamer : public MCELFStreamer {
441public:
442  friend class ARMTargetELFStreamer;
443
444  ARMELFStreamer(MCContext &Context, std::unique_ptr<MCAsmBackend> TAB,
445                 std::unique_ptr<MCObjectWriter> OW, std::unique_ptr<MCCodeEmitter> Emitter,
446                 bool IsThumb)
447      : MCELFStreamer(Context, std::move(TAB), std::move(OW), std::move(Emitter)),
448        IsThumb(IsThumb) {
449    EHReset();
450  }
451
452  ~ARMELFStreamer() override = default;
453
454  void FinishImpl() override;
455
456  // ARM exception handling directives
457  void emitFnStart();
458  void emitFnEnd();
459  void emitCantUnwind();
460  void emitPersonality(const MCSymbol *Per);
461  void emitPersonalityIndex(unsigned index);
462  void emitHandlerData();
463  void emitSetFP(unsigned NewFpReg, unsigned NewSpReg, int64_t Offset = 0);
464  void emitMovSP(unsigned Reg, int64_t Offset = 0);
465  void emitPad(int64_t Offset);
466  void emitRegSave(const SmallVectorImpl<unsigned> &RegList, bool isVector);
467  void emitUnwindRaw(int64_t Offset, const SmallVectorImpl<uint8_t> &Opcodes);
468  void emitFill(const MCExpr &NumBytes, uint64_t FillValue,
469                SMLoc Loc) override {
470    EmitDataMappingSymbol();
471    MCObjectStreamer::emitFill(NumBytes, FillValue, Loc);
472  }
473
474  void ChangeSection(MCSection *Section, const MCExpr *Subsection) override {
475    LastMappingSymbols[getCurrentSection().first] = std::move(LastEMSInfo);
476    MCELFStreamer::ChangeSection(Section, Subsection);
477    auto LastMappingSymbol = LastMappingSymbols.find(Section);
478    if (LastMappingSymbol != LastMappingSymbols.end()) {
479      LastEMSInfo = std::move(LastMappingSymbol->second);
480      return;
481    }
482    LastEMSInfo.reset(new ElfMappingSymbolInfo(SMLoc(), nullptr, 0));
483  }
484
485  /// This function is the one used to emit instruction data into the ELF
486  /// streamer. We override it to add the appropriate mapping symbol if
487  /// necessary.
488  void EmitInstruction(const MCInst &Inst, const MCSubtargetInfo &STI,
489                       bool) override {
490    if (IsThumb)
491      EmitThumbMappingSymbol();
492    else
493      EmitARMMappingSymbol();
494
495    MCELFStreamer::EmitInstruction(Inst, STI);
496  }
497
498  void emitInst(uint32_t Inst, char Suffix) {
499    unsigned Size;
500    char Buffer[4];
501    const bool LittleEndian = getContext().getAsmInfo()->isLittleEndian();
502
503    switch (Suffix) {
504    case '\0':
505      Size = 4;
506
507      assert(!IsThumb);
508      EmitARMMappingSymbol();
509      for (unsigned II = 0, IE = Size; II != IE; II++) {
510        const unsigned I = LittleEndian ? (Size - II - 1) : II;
511        Buffer[Size - II - 1] = uint8_t(Inst >> I * CHAR_BIT);
512      }
513
514      break;
515    case 'n':
516    case 'w':
517      Size = (Suffix == 'n' ? 2 : 4);
518
519      assert(IsThumb);
520      EmitThumbMappingSymbol();
521      // Thumb wide instructions are emitted as a pair of 16-bit words of the
522      // appropriate endianness.
523      for (unsigned II = 0, IE = Size; II != IE; II = II + 2) {
524        const unsigned I0 = LittleEndian ? II + 0 : II + 1;
525        const unsigned I1 = LittleEndian ? II + 1 : II + 0;
526        Buffer[Size - II - 2] = uint8_t(Inst >> I0 * CHAR_BIT);
527        Buffer[Size - II - 1] = uint8_t(Inst >> I1 * CHAR_BIT);
528      }
529
530      break;
531    default:
532      llvm_unreachable("Invalid Suffix");
533    }
534
535    MCELFStreamer::EmitBytes(StringRef(Buffer, Size));
536  }
537
538  /// This is one of the functions used to emit data into an ELF section, so the
539  /// ARM streamer overrides it to add the appropriate mapping symbol ($d) if
540  /// necessary.
541  void EmitBytes(StringRef Data) override {
542    EmitDataMappingSymbol();
543    MCELFStreamer::EmitBytes(Data);
544  }
545
546  void FlushPendingMappingSymbol() {
547    if (!LastEMSInfo->hasInfo())
548      return;
549    ElfMappingSymbolInfo *EMS = LastEMSInfo.get();
550    EmitMappingSymbol("$d", EMS->Loc, EMS->F, EMS->Offset);
551    EMS->resetInfo();
552  }
553
554  /// This is one of the functions used to emit data into an ELF section, so the
555  /// ARM streamer overrides it to add the appropriate mapping symbol ($d) if
556  /// necessary.
557  void EmitValueImpl(const MCExpr *Value, unsigned Size, SMLoc Loc) override {
558    if (const MCSymbolRefExpr *SRE = dyn_cast_or_null<MCSymbolRefExpr>(Value)) {
559      if (SRE->getKind() == MCSymbolRefExpr::VK_ARM_SBREL && !(Size == 4)) {
560        getContext().reportError(Loc, "relocated expression must be 32-bit");
561        return;
562      }
563      getOrCreateDataFragment();
564    }
565
566    EmitDataMappingSymbol();
567    MCELFStreamer::EmitValueImpl(Value, Size, Loc);
568  }
569
570  void EmitAssemblerFlag(MCAssemblerFlag Flag) override {
571    MCELFStreamer::EmitAssemblerFlag(Flag);
572
573    switch (Flag) {
574    case MCAF_SyntaxUnified:
575      return; // no-op here.
576    case MCAF_Code16:
577      IsThumb = true;
578      return; // Change to Thumb mode
579    case MCAF_Code32:
580      IsThumb = false;
581      return; // Change to ARM mode
582    case MCAF_Code64:
583      return;
584    case MCAF_SubsectionsViaSymbols:
585      return;
586    }
587  }
588
589private:
590  enum ElfMappingSymbol {
591    EMS_None,
592    EMS_ARM,
593    EMS_Thumb,
594    EMS_Data
595  };
596
597  struct ElfMappingSymbolInfo {
598    explicit ElfMappingSymbolInfo(SMLoc Loc, MCFragment *F, uint64_t O)
599        : Loc(Loc), F(F), Offset(O), State(EMS_None) {}
600    void resetInfo() {
601      F = nullptr;
602      Offset = 0;
603    }
604    bool hasInfo() { return F != nullptr; }
605    SMLoc Loc;
606    MCFragment *F;
607    uint64_t Offset;
608    ElfMappingSymbol State;
609  };
610
611  void EmitDataMappingSymbol() {
612    if (LastEMSInfo->State == EMS_Data)
613      return;
614    else if (LastEMSInfo->State == EMS_None) {
615      // This is a tentative symbol, it won't really be emitted until it's
616      // actually needed.
617      ElfMappingSymbolInfo *EMS = LastEMSInfo.get();
618      auto *DF = dyn_cast_or_null<MCDataFragment>(getCurrentFragment());
619      if (!DF)
620        return;
621      EMS->Loc = SMLoc();
622      EMS->F = getCurrentFragment();
623      EMS->Offset = DF->getContents().size();
624      LastEMSInfo->State = EMS_Data;
625      return;
626    }
627    EmitMappingSymbol("$d");
628    LastEMSInfo->State = EMS_Data;
629  }
630
631  void EmitThumbMappingSymbol() {
632    if (LastEMSInfo->State == EMS_Thumb)
633      return;
634    FlushPendingMappingSymbol();
635    EmitMappingSymbol("$t");
636    LastEMSInfo->State = EMS_Thumb;
637  }
638
639  void EmitARMMappingSymbol() {
640    if (LastEMSInfo->State == EMS_ARM)
641      return;
642    FlushPendingMappingSymbol();
643    EmitMappingSymbol("$a");
644    LastEMSInfo->State = EMS_ARM;
645  }
646
647  void EmitMappingSymbol(StringRef Name) {
648    auto *Symbol = cast<MCSymbolELF>(getContext().getOrCreateSymbol(
649        Name + "." + Twine(MappingSymbolCounter++)));
650    EmitLabel(Symbol);
651
652    Symbol->setType(ELF::STT_NOTYPE);
653    Symbol->setBinding(ELF::STB_LOCAL);
654    Symbol->setExternal(false);
655  }
656
657  void EmitMappingSymbol(StringRef Name, SMLoc Loc, MCFragment *F,
658                         uint64_t Offset) {
659    auto *Symbol = cast<MCSymbolELF>(getContext().getOrCreateSymbol(
660        Name + "." + Twine(MappingSymbolCounter++)));
661    EmitLabel(Symbol, Loc, F);
662    Symbol->setType(ELF::STT_NOTYPE);
663    Symbol->setBinding(ELF::STB_LOCAL);
664    Symbol->setExternal(false);
665    Symbol->setOffset(Offset);
666  }
667
668  void EmitThumbFunc(MCSymbol *Func) override {
669    getAssembler().setIsThumbFunc(Func);
670    EmitSymbolAttribute(Func, MCSA_ELF_TypeFunction);
671  }
672
673  // Helper functions for ARM exception handling directives
674  void EHReset();
675
676  // Reset state between object emissions
677  void reset() override;
678
679  void EmitPersonalityFixup(StringRef Name);
680  void FlushPendingOffset();
681  void FlushUnwindOpcodes(bool NoHandlerData);
682
683  void SwitchToEHSection(StringRef Prefix, unsigned Type, unsigned Flags,
684                         SectionKind Kind, const MCSymbol &Fn);
685  void SwitchToExTabSection(const MCSymbol &FnStart);
686  void SwitchToExIdxSection(const MCSymbol &FnStart);
687
688  void EmitFixup(const MCExpr *Expr, MCFixupKind Kind);
689
690  bool IsThumb;
691  int64_t MappingSymbolCounter = 0;
692
693  DenseMap<const MCSection *, std::unique_ptr<ElfMappingSymbolInfo>>
694      LastMappingSymbols;
695
696  std::unique_ptr<ElfMappingSymbolInfo> LastEMSInfo;
697
698  // ARM Exception Handling Frame Information
699  MCSymbol *ExTab;
700  MCSymbol *FnStart;
701  const MCSymbol *Personality;
702  unsigned PersonalityIndex;
703  unsigned FPReg; // Frame pointer register
704  int64_t FPOffset; // Offset: (final frame pointer) - (initial $sp)
705  int64_t SPOffset; // Offset: (final $sp) - (initial $sp)
706  int64_t PendingOffset; // Offset: (final $sp) - (emitted $sp)
707  bool UsedFP;
708  bool CantUnwind;
709  SmallVector<uint8_t, 64> Opcodes;
710  UnwindOpcodeAssembler UnwindOpAsm;
711};
712
713} // end anonymous namespace
714
715ARMELFStreamer &ARMTargetELFStreamer::getStreamer() {
716  return static_cast<ARMELFStreamer &>(Streamer);
717}
718
719void ARMTargetELFStreamer::emitFnStart() { getStreamer().emitFnStart(); }
720void ARMTargetELFStreamer::emitFnEnd() { getStreamer().emitFnEnd(); }
721void ARMTargetELFStreamer::emitCantUnwind() { getStreamer().emitCantUnwind(); }
722
723void ARMTargetELFStreamer::emitPersonality(const MCSymbol *Personality) {
724  getStreamer().emitPersonality(Personality);
725}
726
727void ARMTargetELFStreamer::emitPersonalityIndex(unsigned Index) {
728  getStreamer().emitPersonalityIndex(Index);
729}
730
731void ARMTargetELFStreamer::emitHandlerData() {
732  getStreamer().emitHandlerData();
733}
734
735void ARMTargetELFStreamer::emitSetFP(unsigned FpReg, unsigned SpReg,
736                                     int64_t Offset) {
737  getStreamer().emitSetFP(FpReg, SpReg, Offset);
738}
739
740void ARMTargetELFStreamer::emitMovSP(unsigned Reg, int64_t Offset) {
741  getStreamer().emitMovSP(Reg, Offset);
742}
743
744void ARMTargetELFStreamer::emitPad(int64_t Offset) {
745  getStreamer().emitPad(Offset);
746}
747
748void ARMTargetELFStreamer::emitRegSave(const SmallVectorImpl<unsigned> &RegList,
749                                       bool isVector) {
750  getStreamer().emitRegSave(RegList, isVector);
751}
752
753void ARMTargetELFStreamer::emitUnwindRaw(int64_t Offset,
754                                      const SmallVectorImpl<uint8_t> &Opcodes) {
755  getStreamer().emitUnwindRaw(Offset, Opcodes);
756}
757
758void ARMTargetELFStreamer::switchVendor(StringRef Vendor) {
759  assert(!Vendor.empty() && "Vendor cannot be empty.");
760
761  if (CurrentVendor == Vendor)
762    return;
763
764  if (!CurrentVendor.empty())
765    finishAttributeSection();
766
767  assert(Contents.empty() &&
768         ".ARM.attributes should be flushed before changing vendor");
769  CurrentVendor = Vendor;
770
771}
772
773void ARMTargetELFStreamer::emitAttribute(unsigned Attribute, unsigned Value) {
774  setAttributeItem(Attribute, Value, /* OverwriteExisting= */ true);
775}
776
777void ARMTargetELFStreamer::emitTextAttribute(unsigned Attribute,
778                                             StringRef Value) {
779  setAttributeItem(Attribute, Value, /* OverwriteExisting= */ true);
780}
781
782void ARMTargetELFStreamer::emitIntTextAttribute(unsigned Attribute,
783                                                unsigned IntValue,
784                                                StringRef StringValue) {
785  setAttributeItems(Attribute, IntValue, StringValue,
786                    /* OverwriteExisting= */ true);
787}
788
789void ARMTargetELFStreamer::emitArch(ARM::ArchKind Value) {
790  Arch = Value;
791}
792
793void ARMTargetELFStreamer::emitObjectArch(ARM::ArchKind Value) {
794  EmittedArch = Value;
795}
796
797void ARMTargetELFStreamer::emitArchDefaultAttributes() {
798  using namespace ARMBuildAttrs;
799
800  setAttributeItem(CPU_name,
801                   ARM::getCPUAttr(Arch),
802                   false);
803
804  if (EmittedArch == ARM::ArchKind::INVALID)
805    setAttributeItem(CPU_arch,
806                     ARM::getArchAttr(Arch),
807                     false);
808  else
809    setAttributeItem(CPU_arch,
810                     ARM::getArchAttr(EmittedArch),
811                     false);
812
813  switch (Arch) {
814  case ARM::ArchKind::ARMV2:
815  case ARM::ArchKind::ARMV2A:
816  case ARM::ArchKind::ARMV3:
817  case ARM::ArchKind::ARMV3M:
818  case ARM::ArchKind::ARMV4:
819    setAttributeItem(ARM_ISA_use, Allowed, false);
820    break;
821
822  case ARM::ArchKind::ARMV4T:
823  case ARM::ArchKind::ARMV5T:
824  case ARM::ArchKind::ARMV5TE:
825  case ARM::ArchKind::ARMV6:
826    setAttributeItem(ARM_ISA_use, Allowed, false);
827    setAttributeItem(THUMB_ISA_use, Allowed, false);
828    break;
829
830  case ARM::ArchKind::ARMV6T2:
831    setAttributeItem(ARM_ISA_use, Allowed, false);
832    setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
833    break;
834
835  case ARM::ArchKind::ARMV6K:
836  case ARM::ArchKind::ARMV6KZ:
837    setAttributeItem(ARM_ISA_use, Allowed, false);
838    setAttributeItem(THUMB_ISA_use, Allowed, false);
839    setAttributeItem(Virtualization_use, AllowTZ, false);
840    break;
841
842  case ARM::ArchKind::ARMV6M:
843    setAttributeItem(THUMB_ISA_use, Allowed, false);
844    break;
845
846  case ARM::ArchKind::ARMV7A:
847    setAttributeItem(CPU_arch_profile, ApplicationProfile, false);
848    setAttributeItem(ARM_ISA_use, Allowed, false);
849    setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
850    break;
851
852  case ARM::ArchKind::ARMV7R:
853    setAttributeItem(CPU_arch_profile, RealTimeProfile, false);
854    setAttributeItem(ARM_ISA_use, Allowed, false);
855    setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
856    break;
857
858  case ARM::ArchKind::ARMV7EM:
859  case ARM::ArchKind::ARMV7M:
860    setAttributeItem(CPU_arch_profile, MicroControllerProfile, false);
861    setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
862    break;
863
864  case ARM::ArchKind::ARMV8A:
865  case ARM::ArchKind::ARMV8_1A:
866  case ARM::ArchKind::ARMV8_2A:
867  case ARM::ArchKind::ARMV8_3A:
868  case ARM::ArchKind::ARMV8_4A:
869  case ARM::ArchKind::ARMV8_5A:
870    setAttributeItem(CPU_arch_profile, ApplicationProfile, false);
871    setAttributeItem(ARM_ISA_use, Allowed, false);
872    setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
873    setAttributeItem(MPextension_use, Allowed, false);
874    setAttributeItem(Virtualization_use, AllowTZVirtualization, false);
875    break;
876
877  case ARM::ArchKind::ARMV8MBaseline:
878  case ARM::ArchKind::ARMV8MMainline:
879    setAttributeItem(THUMB_ISA_use, AllowThumbDerived, false);
880    setAttributeItem(CPU_arch_profile, MicroControllerProfile, false);
881    break;
882
883  case ARM::ArchKind::IWMMXT:
884    setAttributeItem(ARM_ISA_use, Allowed, false);
885    setAttributeItem(THUMB_ISA_use, Allowed, false);
886    setAttributeItem(WMMX_arch, AllowWMMXv1, false);
887    break;
888
889  case ARM::ArchKind::IWMMXT2:
890    setAttributeItem(ARM_ISA_use, Allowed, false);
891    setAttributeItem(THUMB_ISA_use, Allowed, false);
892    setAttributeItem(WMMX_arch, AllowWMMXv2, false);
893    break;
894
895  default:
896    report_fatal_error("Unknown Arch: " + Twine(ARM::getArchName(Arch)));
897    break;
898  }
899}
900
901void ARMTargetELFStreamer::emitFPU(unsigned Value) {
902  FPU = Value;
903}
904
905void ARMTargetELFStreamer::emitFPUDefaultAttributes() {
906  switch (FPU) {
907  case ARM::FK_VFP:
908  case ARM::FK_VFPV2:
909    setAttributeItem(ARMBuildAttrs::FP_arch,
910                     ARMBuildAttrs::AllowFPv2,
911                     /* OverwriteExisting= */ false);
912    break;
913
914  case ARM::FK_VFPV3:
915    setAttributeItem(ARMBuildAttrs::FP_arch,
916                     ARMBuildAttrs::AllowFPv3A,
917                     /* OverwriteExisting= */ false);
918    break;
919
920  case ARM::FK_VFPV3_FP16:
921    setAttributeItem(ARMBuildAttrs::FP_arch,
922                     ARMBuildAttrs::AllowFPv3A,
923                     /* OverwriteExisting= */ false);
924    setAttributeItem(ARMBuildAttrs::FP_HP_extension,
925                     ARMBuildAttrs::AllowHPFP,
926                     /* OverwriteExisting= */ false);
927    break;
928
929  case ARM::FK_VFPV3_D16:
930    setAttributeItem(ARMBuildAttrs::FP_arch,
931                     ARMBuildAttrs::AllowFPv3B,
932                     /* OverwriteExisting= */ false);
933    break;
934
935  case ARM::FK_VFPV3_D16_FP16:
936    setAttributeItem(ARMBuildAttrs::FP_arch,
937                     ARMBuildAttrs::AllowFPv3B,
938                     /* OverwriteExisting= */ false);
939    setAttributeItem(ARMBuildAttrs::FP_HP_extension,
940                     ARMBuildAttrs::AllowHPFP,
941                     /* OverwriteExisting= */ false);
942    break;
943
944  case ARM::FK_VFPV3XD:
945    setAttributeItem(ARMBuildAttrs::FP_arch,
946                     ARMBuildAttrs::AllowFPv3B,
947                     /* OverwriteExisting= */ false);
948    break;
949  case ARM::FK_VFPV3XD_FP16:
950    setAttributeItem(ARMBuildAttrs::FP_arch,
951                     ARMBuildAttrs::AllowFPv3B,
952                     /* OverwriteExisting= */ false);
953    setAttributeItem(ARMBuildAttrs::FP_HP_extension,
954                     ARMBuildAttrs::AllowHPFP,
955                     /* OverwriteExisting= */ false);
956    break;
957
958  case ARM::FK_VFPV4:
959    setAttributeItem(ARMBuildAttrs::FP_arch,
960                     ARMBuildAttrs::AllowFPv4A,
961                     /* OverwriteExisting= */ false);
962    break;
963
964  // ABI_HardFP_use is handled in ARMAsmPrinter, so _SP_D16 is treated the same
965  // as _D16 here.
966  case ARM::FK_FPV4_SP_D16:
967  case ARM::FK_VFPV4_D16:
968    setAttributeItem(ARMBuildAttrs::FP_arch,
969                     ARMBuildAttrs::AllowFPv4B,
970                     /* OverwriteExisting= */ false);
971    break;
972
973  case ARM::FK_FP_ARMV8:
974    setAttributeItem(ARMBuildAttrs::FP_arch,
975                     ARMBuildAttrs::AllowFPARMv8A,
976                     /* OverwriteExisting= */ false);
977    break;
978
979  // FPV5_D16 is identical to FP_ARMV8 except for the number of D registers, so
980  // uses the FP_ARMV8_D16 build attribute.
981  case ARM::FK_FPV5_SP_D16:
982  case ARM::FK_FPV5_D16:
983    setAttributeItem(ARMBuildAttrs::FP_arch,
984                     ARMBuildAttrs::AllowFPARMv8B,
985                     /* OverwriteExisting= */ false);
986    break;
987
988  case ARM::FK_NEON:
989    setAttributeItem(ARMBuildAttrs::FP_arch,
990                     ARMBuildAttrs::AllowFPv3A,
991                     /* OverwriteExisting= */ false);
992    setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
993                     ARMBuildAttrs::AllowNeon,
994                     /* OverwriteExisting= */ false);
995    break;
996
997  case ARM::FK_NEON_FP16:
998    setAttributeItem(ARMBuildAttrs::FP_arch,
999                     ARMBuildAttrs::AllowFPv3A,
1000                     /* OverwriteExisting= */ false);
1001    setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
1002                     ARMBuildAttrs::AllowNeon,
1003                     /* OverwriteExisting= */ false);
1004    setAttributeItem(ARMBuildAttrs::FP_HP_extension,
1005                     ARMBuildAttrs::AllowHPFP,
1006                     /* OverwriteExisting= */ false);
1007    break;
1008
1009  case ARM::FK_NEON_VFPV4:
1010    setAttributeItem(ARMBuildAttrs::FP_arch,
1011                     ARMBuildAttrs::AllowFPv4A,
1012                     /* OverwriteExisting= */ false);
1013    setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
1014                     ARMBuildAttrs::AllowNeon2,
1015                     /* OverwriteExisting= */ false);
1016    break;
1017
1018  case ARM::FK_NEON_FP_ARMV8:
1019  case ARM::FK_CRYPTO_NEON_FP_ARMV8:
1020    setAttributeItem(ARMBuildAttrs::FP_arch,
1021                     ARMBuildAttrs::AllowFPARMv8A,
1022                     /* OverwriteExisting= */ false);
1023    // 'Advanced_SIMD_arch' must be emitted not here, but within
1024    // ARMAsmPrinter::emitAttributes(), depending on hasV8Ops() and hasV8_1a()
1025    break;
1026
1027  case ARM::FK_SOFTVFP:
1028  case ARM::FK_NONE:
1029    break;
1030
1031  default:
1032    report_fatal_error("Unknown FPU: " + Twine(FPU));
1033    break;
1034  }
1035}
1036
1037size_t ARMTargetELFStreamer::calculateContentSize() const {
1038  size_t Result = 0;
1039  for (size_t i = 0; i < Contents.size(); ++i) {
1040    AttributeItem item = Contents[i];
1041    switch (item.Type) {
1042    case AttributeItem::HiddenAttribute:
1043      break;
1044    case AttributeItem::NumericAttribute:
1045      Result += getULEB128Size(item.Tag);
1046      Result += getULEB128Size(item.IntValue);
1047      break;
1048    case AttributeItem::TextAttribute:
1049      Result += getULEB128Size(item.Tag);
1050      Result += item.StringValue.size() + 1; // string + '\0'
1051      break;
1052    case AttributeItem::NumericAndTextAttributes:
1053      Result += getULEB128Size(item.Tag);
1054      Result += getULEB128Size(item.IntValue);
1055      Result += item.StringValue.size() + 1; // string + '\0';
1056      break;
1057    }
1058  }
1059  return Result;
1060}
1061
1062void ARMTargetELFStreamer::finishAttributeSection() {
1063  // <format-version>
1064  // [ <section-length> "vendor-name"
1065  // [ <file-tag> <size> <attribute>*
1066  //   | <section-tag> <size> <section-number>* 0 <attribute>*
1067  //   | <symbol-tag> <size> <symbol-number>* 0 <attribute>*
1068  //   ]+
1069  // ]*
1070
1071  if (FPU != ARM::FK_INVALID)
1072    emitFPUDefaultAttributes();
1073
1074  if (Arch != ARM::ArchKind::INVALID)
1075    emitArchDefaultAttributes();
1076
1077  if (Contents.empty())
1078    return;
1079
1080  llvm::sort(Contents, AttributeItem::LessTag);
1081
1082  ARMELFStreamer &Streamer = getStreamer();
1083
1084  // Switch to .ARM.attributes section
1085  if (AttributeSection) {
1086    Streamer.SwitchSection(AttributeSection);
1087  } else {
1088    AttributeSection = Streamer.getContext().getELFSection(
1089        ".ARM.attributes", ELF::SHT_ARM_ATTRIBUTES, 0);
1090    Streamer.SwitchSection(AttributeSection);
1091
1092    // Format version
1093    Streamer.EmitIntValue(0x41, 1);
1094  }
1095
1096  // Vendor size + Vendor name + '\0'
1097  const size_t VendorHeaderSize = 4 + CurrentVendor.size() + 1;
1098
1099  // Tag + Tag Size
1100  const size_t TagHeaderSize = 1 + 4;
1101
1102  const size_t ContentsSize = calculateContentSize();
1103
1104  Streamer.EmitIntValue(VendorHeaderSize + TagHeaderSize + ContentsSize, 4);
1105  Streamer.EmitBytes(CurrentVendor);
1106  Streamer.EmitIntValue(0, 1); // '\0'
1107
1108  Streamer.EmitIntValue(ARMBuildAttrs::File, 1);
1109  Streamer.EmitIntValue(TagHeaderSize + ContentsSize, 4);
1110
1111  // Size should have been accounted for already, now
1112  // emit each field as its type (ULEB or String)
1113  for (size_t i = 0; i < Contents.size(); ++i) {
1114    AttributeItem item = Contents[i];
1115    Streamer.EmitULEB128IntValue(item.Tag);
1116    switch (item.Type) {
1117    default: llvm_unreachable("Invalid attribute type");
1118    case AttributeItem::NumericAttribute:
1119      Streamer.EmitULEB128IntValue(item.IntValue);
1120      break;
1121    case AttributeItem::TextAttribute:
1122      Streamer.EmitBytes(item.StringValue);
1123      Streamer.EmitIntValue(0, 1); // '\0'
1124      break;
1125    case AttributeItem::NumericAndTextAttributes:
1126      Streamer.EmitULEB128IntValue(item.IntValue);
1127      Streamer.EmitBytes(item.StringValue);
1128      Streamer.EmitIntValue(0, 1); // '\0'
1129      break;
1130    }
1131  }
1132
1133  Contents.clear();
1134  FPU = ARM::FK_INVALID;
1135}
1136
1137void ARMTargetELFStreamer::emitLabel(MCSymbol *Symbol) {
1138  ARMELFStreamer &Streamer = getStreamer();
1139  if (!Streamer.IsThumb)
1140    return;
1141
1142  Streamer.getAssembler().registerSymbol(*Symbol);
1143  unsigned Type = cast<MCSymbolELF>(Symbol)->getType();
1144  if (Type == ELF::STT_FUNC || Type == ELF::STT_GNU_IFUNC)
1145    Streamer.EmitThumbFunc(Symbol);
1146}
1147
1148void
1149ARMTargetELFStreamer::AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *S) {
1150  getStreamer().EmitFixup(S, FK_Data_4);
1151}
1152
1153void ARMTargetELFStreamer::emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) {
1154  if (const MCSymbolRefExpr *SRE = dyn_cast<MCSymbolRefExpr>(Value)) {
1155    const MCSymbol &Sym = SRE->getSymbol();
1156    if (!Sym.isDefined()) {
1157      getStreamer().EmitAssignment(Symbol, Value);
1158      return;
1159    }
1160  }
1161
1162  getStreamer().EmitThumbFunc(Symbol);
1163  getStreamer().EmitAssignment(Symbol, Value);
1164}
1165
1166void ARMTargetELFStreamer::emitInst(uint32_t Inst, char Suffix) {
1167  getStreamer().emitInst(Inst, Suffix);
1168}
1169
1170void ARMTargetELFStreamer::reset() { AttributeSection = nullptr; }
1171
1172void ARMELFStreamer::FinishImpl() {
1173  MCTargetStreamer &TS = *getTargetStreamer();
1174  ARMTargetStreamer &ATS = static_cast<ARMTargetStreamer &>(TS);
1175  ATS.finishAttributeSection();
1176
1177  MCELFStreamer::FinishImpl();
1178}
1179
1180void ARMELFStreamer::reset() {
1181  MCTargetStreamer &TS = *getTargetStreamer();
1182  ARMTargetStreamer &ATS = static_cast<ARMTargetStreamer &>(TS);
1183  ATS.reset();
1184  MappingSymbolCounter = 0;
1185  MCELFStreamer::reset();
1186  LastMappingSymbols.clear();
1187  LastEMSInfo.reset();
1188  // MCELFStreamer clear's the assembler's e_flags. However, for
1189  // arm we manually set the ABI version on streamer creation, so
1190  // do the same here
1191  getAssembler().setELFHeaderEFlags(ELF::EF_ARM_EABI_VER5);
1192}
1193
1194inline void ARMELFStreamer::SwitchToEHSection(StringRef Prefix,
1195                                              unsigned Type,
1196                                              unsigned Flags,
1197                                              SectionKind Kind,
1198                                              const MCSymbol &Fn) {
1199  const MCSectionELF &FnSection =
1200    static_cast<const MCSectionELF &>(Fn.getSection());
1201
1202  // Create the name for new section
1203  StringRef FnSecName(FnSection.getSectionName());
1204  SmallString<128> EHSecName(Prefix);
1205  if (FnSecName != ".text") {
1206    EHSecName += FnSecName;
1207  }
1208
1209  // Get .ARM.extab or .ARM.exidx section
1210  const MCSymbolELF *Group = FnSection.getGroup();
1211  if (Group)
1212    Flags |= ELF::SHF_GROUP;
1213  MCSectionELF *EHSection = getContext().getELFSection(
1214      EHSecName, Type, Flags, 0, Group, FnSection.getUniqueID(),
1215      static_cast<const MCSymbolELF *>(&Fn));
1216
1217  assert(EHSection && "Failed to get the required EH section");
1218
1219  // Switch to .ARM.extab or .ARM.exidx section
1220  SwitchSection(EHSection);
1221  EmitCodeAlignment(4);
1222}
1223
1224inline void ARMELFStreamer::SwitchToExTabSection(const MCSymbol &FnStart) {
1225  SwitchToEHSection(".ARM.extab", ELF::SHT_PROGBITS, ELF::SHF_ALLOC,
1226                    SectionKind::getData(), FnStart);
1227}
1228
1229inline void ARMELFStreamer::SwitchToExIdxSection(const MCSymbol &FnStart) {
1230  SwitchToEHSection(".ARM.exidx", ELF::SHT_ARM_EXIDX,
1231                    ELF::SHF_ALLOC | ELF::SHF_LINK_ORDER,
1232                    SectionKind::getData(), FnStart);
1233}
1234
1235void ARMELFStreamer::EmitFixup(const MCExpr *Expr, MCFixupKind Kind) {
1236  MCDataFragment *Frag = getOrCreateDataFragment();
1237  Frag->getFixups().push_back(MCFixup::create(Frag->getContents().size(), Expr,
1238                                              Kind));
1239}
1240
1241void ARMELFStreamer::EHReset() {
1242  ExTab = nullptr;
1243  FnStart = nullptr;
1244  Personality = nullptr;
1245  PersonalityIndex = ARM::EHABI::NUM_PERSONALITY_INDEX;
1246  FPReg = ARM::SP;
1247  FPOffset = 0;
1248  SPOffset = 0;
1249  PendingOffset = 0;
1250  UsedFP = false;
1251  CantUnwind = false;
1252
1253  Opcodes.clear();
1254  UnwindOpAsm.Reset();
1255}
1256
1257void ARMELFStreamer::emitFnStart() {
1258  assert(FnStart == nullptr);
1259  FnStart = getContext().createTempSymbol();
1260  EmitLabel(FnStart);
1261}
1262
1263void ARMELFStreamer::emitFnEnd() {
1264  assert(FnStart && ".fnstart must precedes .fnend");
1265
1266  // Emit unwind opcodes if there is no .handlerdata directive
1267  if (!ExTab && !CantUnwind)
1268    FlushUnwindOpcodes(true);
1269
1270  // Emit the exception index table entry
1271  SwitchToExIdxSection(*FnStart);
1272
1273  if (PersonalityIndex < ARM::EHABI::NUM_PERSONALITY_INDEX)
1274    EmitPersonalityFixup(GetAEABIUnwindPersonalityName(PersonalityIndex));
1275
1276  const MCSymbolRefExpr *FnStartRef =
1277    MCSymbolRefExpr::create(FnStart,
1278                            MCSymbolRefExpr::VK_ARM_PREL31,
1279                            getContext());
1280
1281  EmitValue(FnStartRef, 4);
1282
1283  if (CantUnwind) {
1284    EmitIntValue(ARM::EHABI::EXIDX_CANTUNWIND, 4);
1285  } else if (ExTab) {
1286    // Emit a reference to the unwind opcodes in the ".ARM.extab" section.
1287    const MCSymbolRefExpr *ExTabEntryRef =
1288      MCSymbolRefExpr::create(ExTab,
1289                              MCSymbolRefExpr::VK_ARM_PREL31,
1290                              getContext());
1291    EmitValue(ExTabEntryRef, 4);
1292  } else {
1293    // For the __aeabi_unwind_cpp_pr0, we have to emit the unwind opcodes in
1294    // the second word of exception index table entry.  The size of the unwind
1295    // opcodes should always be 4 bytes.
1296    assert(PersonalityIndex == ARM::EHABI::AEABI_UNWIND_CPP_PR0 &&
1297           "Compact model must use __aeabi_unwind_cpp_pr0 as personality");
1298    assert(Opcodes.size() == 4u &&
1299           "Unwind opcode size for __aeabi_unwind_cpp_pr0 must be equal to 4");
1300    uint64_t Intval = Opcodes[0] |
1301                      Opcodes[1] << 8 |
1302                      Opcodes[2] << 16 |
1303                      Opcodes[3] << 24;
1304    EmitIntValue(Intval, Opcodes.size());
1305  }
1306
1307  // Switch to the section containing FnStart
1308  SwitchSection(&FnStart->getSection());
1309
1310  // Clean exception handling frame information
1311  EHReset();
1312}
1313
1314void ARMELFStreamer::emitCantUnwind() { CantUnwind = true; }
1315
1316// Add the R_ARM_NONE fixup at the same position
1317void ARMELFStreamer::EmitPersonalityFixup(StringRef Name) {
1318  const MCSymbol *PersonalitySym = getContext().getOrCreateSymbol(Name);
1319
1320  const MCSymbolRefExpr *PersonalityRef = MCSymbolRefExpr::create(
1321      PersonalitySym, MCSymbolRefExpr::VK_ARM_NONE, getContext());
1322
1323  visitUsedExpr(*PersonalityRef);
1324  MCDataFragment *DF = getOrCreateDataFragment();
1325  DF->getFixups().push_back(MCFixup::create(DF->getContents().size(),
1326                                            PersonalityRef,
1327                                            MCFixup::getKindForSize(4, false)));
1328}
1329
1330void ARMELFStreamer::FlushPendingOffset() {
1331  if (PendingOffset != 0) {
1332    UnwindOpAsm.EmitSPOffset(-PendingOffset);
1333    PendingOffset = 0;
1334  }
1335}
1336
1337void ARMELFStreamer::FlushUnwindOpcodes(bool NoHandlerData) {
1338  // Emit the unwind opcode to restore $sp.
1339  if (UsedFP) {
1340    const MCRegisterInfo *MRI = getContext().getRegisterInfo();
1341    int64_t LastRegSaveSPOffset = SPOffset - PendingOffset;
1342    UnwindOpAsm.EmitSPOffset(LastRegSaveSPOffset - FPOffset);
1343    UnwindOpAsm.EmitSetSP(MRI->getEncodingValue(FPReg));
1344  } else {
1345    FlushPendingOffset();
1346  }
1347
1348  // Finalize the unwind opcode sequence
1349  UnwindOpAsm.Finalize(PersonalityIndex, Opcodes);
1350
1351  // For compact model 0, we have to emit the unwind opcodes in the .ARM.exidx
1352  // section.  Thus, we don't have to create an entry in the .ARM.extab
1353  // section.
1354  if (NoHandlerData && PersonalityIndex == ARM::EHABI::AEABI_UNWIND_CPP_PR0)
1355    return;
1356
1357  // Switch to .ARM.extab section.
1358  SwitchToExTabSection(*FnStart);
1359
1360  // Create .ARM.extab label for offset in .ARM.exidx
1361  assert(!ExTab);
1362  ExTab = getContext().createTempSymbol();
1363  EmitLabel(ExTab);
1364
1365  // Emit personality
1366  if (Personality) {
1367    const MCSymbolRefExpr *PersonalityRef =
1368      MCSymbolRefExpr::create(Personality,
1369                              MCSymbolRefExpr::VK_ARM_PREL31,
1370                              getContext());
1371
1372    EmitValue(PersonalityRef, 4);
1373  }
1374
1375  // Emit unwind opcodes
1376  assert((Opcodes.size() % 4) == 0 &&
1377         "Unwind opcode size for __aeabi_cpp_unwind_pr0 must be multiple of 4");
1378  for (unsigned I = 0; I != Opcodes.size(); I += 4) {
1379    uint64_t Intval = Opcodes[I] |
1380                      Opcodes[I + 1] << 8 |
1381                      Opcodes[I + 2] << 16 |
1382                      Opcodes[I + 3] << 24;
1383    EmitIntValue(Intval, 4);
1384  }
1385
1386  // According to ARM EHABI section 9.2, if the __aeabi_unwind_cpp_pr1() or
1387  // __aeabi_unwind_cpp_pr2() is used, then the handler data must be emitted
1388  // after the unwind opcodes.  The handler data consists of several 32-bit
1389  // words, and should be terminated by zero.
1390  //
1391  // In case that the .handlerdata directive is not specified by the
1392  // programmer, we should emit zero to terminate the handler data.
1393  if (NoHandlerData && !Personality)
1394    EmitIntValue(0, 4);
1395}
1396
1397void ARMELFStreamer::emitHandlerData() { FlushUnwindOpcodes(false); }
1398
1399void ARMELFStreamer::emitPersonality(const MCSymbol *Per) {
1400  Personality = Per;
1401  UnwindOpAsm.setPersonality(Per);
1402}
1403
1404void ARMELFStreamer::emitPersonalityIndex(unsigned Index) {
1405  assert(Index < ARM::EHABI::NUM_PERSONALITY_INDEX && "invalid index");
1406  PersonalityIndex = Index;
1407}
1408
1409void ARMELFStreamer::emitSetFP(unsigned NewFPReg, unsigned NewSPReg,
1410                               int64_t Offset) {
1411  assert((NewSPReg == ARM::SP || NewSPReg == FPReg) &&
1412         "the operand of .setfp directive should be either $sp or $fp");
1413
1414  UsedFP = true;
1415  FPReg = NewFPReg;
1416
1417  if (NewSPReg == ARM::SP)
1418    FPOffset = SPOffset + Offset;
1419  else
1420    FPOffset += Offset;
1421}
1422
1423void ARMELFStreamer::emitMovSP(unsigned Reg, int64_t Offset) {
1424  assert((Reg != ARM::SP && Reg != ARM::PC) &&
1425         "the operand of .movsp cannot be either sp or pc");
1426  assert(FPReg == ARM::SP && "current FP must be SP");
1427
1428  FlushPendingOffset();
1429
1430  FPReg = Reg;
1431  FPOffset = SPOffset + Offset;
1432
1433  const MCRegisterInfo *MRI = getContext().getRegisterInfo();
1434  UnwindOpAsm.EmitSetSP(MRI->getEncodingValue(FPReg));
1435}
1436
1437void ARMELFStreamer::emitPad(int64_t Offset) {
1438  // Track the change of the $sp offset
1439  SPOffset -= Offset;
1440
1441  // To squash multiple .pad directives, we should delay the unwind opcode
1442  // until the .save, .vsave, .handlerdata, or .fnend directives.
1443  PendingOffset -= Offset;
1444}
1445
1446void ARMELFStreamer::emitRegSave(const SmallVectorImpl<unsigned> &RegList,
1447                                 bool IsVector) {
1448  // Collect the registers in the register list
1449  unsigned Count = 0;
1450  uint32_t Mask = 0;
1451  const MCRegisterInfo *MRI = getContext().getRegisterInfo();
1452  for (size_t i = 0; i < RegList.size(); ++i) {
1453    unsigned Reg = MRI->getEncodingValue(RegList[i]);
1454    assert(Reg < (IsVector ? 32U : 16U) && "Register out of range");
1455    unsigned Bit = (1u << Reg);
1456    if ((Mask & Bit) == 0) {
1457      Mask |= Bit;
1458      ++Count;
1459    }
1460  }
1461
1462  // Track the change the $sp offset: For the .save directive, the
1463  // corresponding push instruction will decrease the $sp by (4 * Count).
1464  // For the .vsave directive, the corresponding vpush instruction will
1465  // decrease $sp by (8 * Count).
1466  SPOffset -= Count * (IsVector ? 8 : 4);
1467
1468  // Emit the opcode
1469  FlushPendingOffset();
1470  if (IsVector)
1471    UnwindOpAsm.EmitVFPRegSave(Mask);
1472  else
1473    UnwindOpAsm.EmitRegSave(Mask);
1474}
1475
1476void ARMELFStreamer::emitUnwindRaw(int64_t Offset,
1477                                   const SmallVectorImpl<uint8_t> &Opcodes) {
1478  FlushPendingOffset();
1479  SPOffset = SPOffset - Offset;
1480  UnwindOpAsm.EmitRaw(Opcodes);
1481}
1482
1483namespace llvm {
1484
1485MCTargetStreamer *createARMTargetAsmStreamer(MCStreamer &S,
1486                                             formatted_raw_ostream &OS,
1487                                             MCInstPrinter *InstPrint,
1488                                             bool isVerboseAsm) {
1489  return new ARMTargetAsmStreamer(S, OS, *InstPrint, isVerboseAsm);
1490}
1491
1492MCTargetStreamer *createARMNullTargetStreamer(MCStreamer &S) {
1493  return new ARMTargetStreamer(S);
1494}
1495
1496MCTargetStreamer *createARMObjectTargetStreamer(MCStreamer &S,
1497                                                const MCSubtargetInfo &STI) {
1498  const Triple &TT = STI.getTargetTriple();
1499  if (TT.isOSBinFormatELF())
1500    return new ARMTargetELFStreamer(S);
1501  return new ARMTargetStreamer(S);
1502}
1503
1504MCELFStreamer *createARMELFStreamer(MCContext &Context,
1505                                    std::unique_ptr<MCAsmBackend> TAB,
1506                                    std::unique_ptr<MCObjectWriter> OW,
1507                                    std::unique_ptr<MCCodeEmitter> Emitter,
1508                                    bool RelaxAll, bool IsThumb) {
1509  ARMELFStreamer *S = new ARMELFStreamer(Context, std::move(TAB), std::move(OW),
1510                                         std::move(Emitter), IsThumb);
1511  // FIXME: This should eventually end up somewhere else where more
1512  // intelligent flag decisions can be made. For now we are just maintaining
1513  // the status quo for ARM and setting EF_ARM_EABI_VER5 as the default.
1514  S->getAssembler().setELFHeaderEFlags(ELF::EF_ARM_EABI_VER5);
1515
1516  if (RelaxAll)
1517    S->getAssembler().setRelaxAll(true);
1518  return S;
1519}
1520
1521} // end namespace llvm
1522