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/StringExtras.h"
19#include "llvm/ADT/Twine.h"
20#include "llvm/MC/MCAsmBackend.h"
21#include "llvm/MC/MCAsmInfo.h"
22#include "llvm/MC/MCAssembler.h"
23#include "llvm/MC/MCCodeEmitter.h"
24#include "llvm/MC/MCContext.h"
25#include "llvm/MC/MCELFStreamer.h"
26#include "llvm/MC/MCExpr.h"
27#include "llvm/MC/MCInst.h"
28#include "llvm/MC/MCInstPrinter.h"
29#include "llvm/MC/MCObjectFileInfo.h"
30#include "llvm/MC/MCObjectStreamer.h"
31#include "llvm/MC/MCRegisterInfo.h"
32#include "llvm/MC/MCSection.h"
33#include "llvm/MC/MCSectionELF.h"
34#include "llvm/MC/MCStreamer.h"
35#include "llvm/MC/MCSymbolELF.h"
36#include "llvm/MC/MCValue.h"
37#include "llvm/Support/ARMBuildAttributes.h"
38#include "llvm/Support/ARMEHABI.h"
39#include "llvm/Support/TargetParser.h"
40#include "llvm/Support/Debug.h"
41#include "llvm/Support/ELF.h"
42#include "llvm/Support/FormattedStream.h"
43#include "llvm/Support/LEB128.h"
44#include "llvm/Support/raw_ostream.h"
45#include <algorithm>
46
47using namespace llvm;
48
49static std::string GetAEABIUnwindPersonalityName(unsigned Index) {
50  assert(Index < ARM::EHABI::NUM_PERSONALITY_INDEX &&
51         "Invalid personality index");
52  return (Twine("__aeabi_unwind_cpp_pr") + Twine(Index)).str();
53}
54
55namespace {
56
57class ARMELFStreamer;
58
59class ARMTargetAsmStreamer : public ARMTargetStreamer {
60  formatted_raw_ostream &OS;
61  MCInstPrinter &InstPrinter;
62  bool IsVerboseAsm;
63
64  void emitFnStart() override;
65  void emitFnEnd() override;
66  void emitCantUnwind() override;
67  void emitPersonality(const MCSymbol *Personality) override;
68  void emitPersonalityIndex(unsigned Index) override;
69  void emitHandlerData() override;
70  void emitSetFP(unsigned FpReg, unsigned SpReg, int64_t Offset = 0) override;
71  void emitMovSP(unsigned Reg, int64_t Offset = 0) override;
72  void emitPad(int64_t Offset) override;
73  void emitRegSave(const SmallVectorImpl<unsigned> &RegList,
74                   bool isVector) override;
75  void emitUnwindRaw(int64_t Offset,
76                     const SmallVectorImpl<uint8_t> &Opcodes) override;
77
78  void switchVendor(StringRef Vendor) override;
79  void emitAttribute(unsigned Attribute, unsigned Value) override;
80  void emitTextAttribute(unsigned Attribute, StringRef String) override;
81  void emitIntTextAttribute(unsigned Attribute, unsigned IntValue,
82                            StringRef StringValue) override;
83  void emitArch(unsigned Arch) override;
84  void emitArchExtension(unsigned ArchExt) override;
85  void emitObjectArch(unsigned Arch) override;
86  void emitFPU(unsigned FPU) override;
87  void emitInst(uint32_t Inst, char Suffix = '\0') override;
88  void finishAttributeSection() override;
89
90  void AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *SRE) override;
91  void emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) override;
92
93public:
94  ARMTargetAsmStreamer(MCStreamer &S, formatted_raw_ostream &OS,
95                       MCInstPrinter &InstPrinter, bool VerboseAsm);
96};
97
98ARMTargetAsmStreamer::ARMTargetAsmStreamer(MCStreamer &S,
99                                           formatted_raw_ostream &OS,
100                                           MCInstPrinter &InstPrinter,
101                                           bool VerboseAsm)
102    : ARMTargetStreamer(S), OS(OS), InstPrinter(InstPrinter),
103      IsVerboseAsm(VerboseAsm) {}
104void ARMTargetAsmStreamer::emitFnStart() { OS << "\t.fnstart\n"; }
105void ARMTargetAsmStreamer::emitFnEnd() { OS << "\t.fnend\n"; }
106void ARMTargetAsmStreamer::emitCantUnwind() { OS << "\t.cantunwind\n"; }
107void ARMTargetAsmStreamer::emitPersonality(const MCSymbol *Personality) {
108  OS << "\t.personality " << Personality->getName() << '\n';
109}
110void ARMTargetAsmStreamer::emitPersonalityIndex(unsigned Index) {
111  OS << "\t.personalityindex " << Index << '\n';
112}
113void ARMTargetAsmStreamer::emitHandlerData() { OS << "\t.handlerdata\n"; }
114void ARMTargetAsmStreamer::emitSetFP(unsigned FpReg, unsigned SpReg,
115                                     int64_t Offset) {
116  OS << "\t.setfp\t";
117  InstPrinter.printRegName(OS, FpReg);
118  OS << ", ";
119  InstPrinter.printRegName(OS, SpReg);
120  if (Offset)
121    OS << ", #" << Offset;
122  OS << '\n';
123}
124void ARMTargetAsmStreamer::emitMovSP(unsigned Reg, int64_t Offset) {
125  assert((Reg != ARM::SP && Reg != ARM::PC) &&
126         "the operand of .movsp cannot be either sp or pc");
127
128  OS << "\t.movsp\t";
129  InstPrinter.printRegName(OS, Reg);
130  if (Offset)
131    OS << ", #" << Offset;
132  OS << '\n';
133}
134void ARMTargetAsmStreamer::emitPad(int64_t Offset) {
135  OS << "\t.pad\t#" << Offset << '\n';
136}
137void ARMTargetAsmStreamer::emitRegSave(const SmallVectorImpl<unsigned> &RegList,
138                                       bool isVector) {
139  assert(RegList.size() && "RegList should not be empty");
140  if (isVector)
141    OS << "\t.vsave\t{";
142  else
143    OS << "\t.save\t{";
144
145  InstPrinter.printRegName(OS, RegList[0]);
146
147  for (unsigned i = 1, e = RegList.size(); i != e; ++i) {
148    OS << ", ";
149    InstPrinter.printRegName(OS, RegList[i]);
150  }
151
152  OS << "}\n";
153}
154void ARMTargetAsmStreamer::switchVendor(StringRef Vendor) {
155}
156void ARMTargetAsmStreamer::emitAttribute(unsigned Attribute, unsigned Value) {
157  OS << "\t.eabi_attribute\t" << Attribute << ", " << Twine(Value);
158  if (IsVerboseAsm) {
159    StringRef Name = ARMBuildAttrs::AttrTypeAsString(Attribute);
160    if (!Name.empty())
161      OS << "\t@ " << Name;
162  }
163  OS << "\n";
164}
165void ARMTargetAsmStreamer::emitTextAttribute(unsigned Attribute,
166                                             StringRef String) {
167  switch (Attribute) {
168  case ARMBuildAttrs::CPU_name:
169    OS << "\t.cpu\t" << String.lower();
170    break;
171  default:
172    OS << "\t.eabi_attribute\t" << Attribute << ", \"" << String << "\"";
173    if (IsVerboseAsm) {
174      StringRef Name = ARMBuildAttrs::AttrTypeAsString(Attribute);
175      if (!Name.empty())
176        OS << "\t@ " << Name;
177    }
178    break;
179  }
180  OS << "\n";
181}
182void ARMTargetAsmStreamer::emitIntTextAttribute(unsigned Attribute,
183                                                unsigned IntValue,
184                                                StringRef StringValue) {
185  switch (Attribute) {
186  default: llvm_unreachable("unsupported multi-value attribute in asm mode");
187  case ARMBuildAttrs::compatibility:
188    OS << "\t.eabi_attribute\t" << Attribute << ", " << IntValue;
189    if (!StringValue.empty())
190      OS << ", \"" << StringValue << "\"";
191    if (IsVerboseAsm)
192      OS << "\t@ " << ARMBuildAttrs::AttrTypeAsString(Attribute);
193    break;
194  }
195  OS << "\n";
196}
197void ARMTargetAsmStreamer::emitArch(unsigned Arch) {
198  OS << "\t.arch\t" << ARM::getArchName(Arch) << "\n";
199}
200void ARMTargetAsmStreamer::emitArchExtension(unsigned ArchExt) {
201  OS << "\t.arch_extension\t" << ARM::getArchExtName(ArchExt) << "\n";
202}
203void ARMTargetAsmStreamer::emitObjectArch(unsigned Arch) {
204  OS << "\t.object_arch\t" << ARM::getArchName(Arch) << '\n';
205}
206void ARMTargetAsmStreamer::emitFPU(unsigned FPU) {
207  OS << "\t.fpu\t" << ARM::getFPUName(FPU) << "\n";
208}
209void ARMTargetAsmStreamer::finishAttributeSection() {
210}
211void
212ARMTargetAsmStreamer::AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *S) {
213  OS << "\t.tlsdescseq\t" << S->getSymbol().getName();
214}
215
216void ARMTargetAsmStreamer::emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) {
217  const MCAsmInfo *MAI = Streamer.getContext().getAsmInfo();
218
219  OS << "\t.thumb_set\t";
220  Symbol->print(OS, MAI);
221  OS << ", ";
222  Value->print(OS, MAI);
223  OS << '\n';
224}
225
226void ARMTargetAsmStreamer::emitInst(uint32_t Inst, char Suffix) {
227  OS << "\t.inst";
228  if (Suffix)
229    OS << "." << Suffix;
230  OS << "\t0x" << Twine::utohexstr(Inst) << "\n";
231}
232
233void ARMTargetAsmStreamer::emitUnwindRaw(int64_t Offset,
234                                      const SmallVectorImpl<uint8_t> &Opcodes) {
235  OS << "\t.unwind_raw " << Offset;
236  for (SmallVectorImpl<uint8_t>::const_iterator OCI = Opcodes.begin(),
237                                                OCE = Opcodes.end();
238       OCI != OCE; ++OCI)
239    OS << ", 0x" << Twine::utohexstr(*OCI);
240  OS << '\n';
241}
242
243class ARMTargetELFStreamer : public ARMTargetStreamer {
244private:
245  // This structure holds all attributes, accounting for
246  // their string/numeric value, so we can later emit them
247  // in declaration order, keeping all in the same vector
248  struct AttributeItem {
249    enum {
250      HiddenAttribute = 0,
251      NumericAttribute,
252      TextAttribute,
253      NumericAndTextAttributes
254    } Type;
255    unsigned Tag;
256    unsigned IntValue;
257    std::string StringValue;
258
259    static bool LessTag(const AttributeItem &LHS, const AttributeItem &RHS) {
260      // The conformance tag must be emitted first when serialised
261      // into an object file. Specifically, the addenda to the ARM ABI
262      // states that (2.3.7.4):
263      //
264      // "To simplify recognition by consumers in the common case of
265      // claiming conformity for the whole file, this tag should be
266      // emitted first in a file-scope sub-subsection of the first
267      // public subsection of the attributes section."
268      //
269      // So it is special-cased in this comparison predicate when the
270      // attributes are sorted in finishAttributeSection().
271      return (RHS.Tag != ARMBuildAttrs::conformance) &&
272             ((LHS.Tag == ARMBuildAttrs::conformance) || (LHS.Tag < RHS.Tag));
273    }
274  };
275
276  StringRef CurrentVendor;
277  unsigned FPU;
278  unsigned Arch;
279  unsigned EmittedArch;
280  SmallVector<AttributeItem, 64> Contents;
281
282  MCSection *AttributeSection;
283
284  AttributeItem *getAttributeItem(unsigned Attribute) {
285    for (size_t i = 0; i < Contents.size(); ++i)
286      if (Contents[i].Tag == Attribute)
287        return &Contents[i];
288    return nullptr;
289  }
290
291  void setAttributeItem(unsigned Attribute, unsigned Value,
292                        bool OverwriteExisting) {
293    // Look for existing attribute item
294    if (AttributeItem *Item = getAttributeItem(Attribute)) {
295      if (!OverwriteExisting)
296        return;
297      Item->Type = AttributeItem::NumericAttribute;
298      Item->IntValue = Value;
299      return;
300    }
301
302    // Create new attribute item
303    AttributeItem Item = {
304      AttributeItem::NumericAttribute,
305      Attribute,
306      Value,
307      StringRef("")
308    };
309    Contents.push_back(Item);
310  }
311
312  void setAttributeItem(unsigned Attribute, StringRef Value,
313                        bool OverwriteExisting) {
314    // Look for existing attribute item
315    if (AttributeItem *Item = getAttributeItem(Attribute)) {
316      if (!OverwriteExisting)
317        return;
318      Item->Type = AttributeItem::TextAttribute;
319      Item->StringValue = Value;
320      return;
321    }
322
323    // Create new attribute item
324    AttributeItem Item = {
325      AttributeItem::TextAttribute,
326      Attribute,
327      0,
328      Value
329    };
330    Contents.push_back(Item);
331  }
332
333  void setAttributeItems(unsigned Attribute, unsigned IntValue,
334                         StringRef StringValue, bool OverwriteExisting) {
335    // Look for existing attribute item
336    if (AttributeItem *Item = getAttributeItem(Attribute)) {
337      if (!OverwriteExisting)
338        return;
339      Item->Type = AttributeItem::NumericAndTextAttributes;
340      Item->IntValue = IntValue;
341      Item->StringValue = StringValue;
342      return;
343    }
344
345    // Create new attribute item
346    AttributeItem Item = {
347      AttributeItem::NumericAndTextAttributes,
348      Attribute,
349      IntValue,
350      StringValue
351    };
352    Contents.push_back(Item);
353  }
354
355  void emitArchDefaultAttributes();
356  void emitFPUDefaultAttributes();
357
358  ARMELFStreamer &getStreamer();
359
360  void emitFnStart() override;
361  void emitFnEnd() override;
362  void emitCantUnwind() override;
363  void emitPersonality(const MCSymbol *Personality) override;
364  void emitPersonalityIndex(unsigned Index) override;
365  void emitHandlerData() override;
366  void emitSetFP(unsigned FpReg, unsigned SpReg, int64_t Offset = 0) override;
367  void emitMovSP(unsigned Reg, int64_t Offset = 0) override;
368  void emitPad(int64_t Offset) override;
369  void emitRegSave(const SmallVectorImpl<unsigned> &RegList,
370                   bool isVector) override;
371  void emitUnwindRaw(int64_t Offset,
372                     const SmallVectorImpl<uint8_t> &Opcodes) override;
373
374  void switchVendor(StringRef Vendor) override;
375  void emitAttribute(unsigned Attribute, unsigned Value) override;
376  void emitTextAttribute(unsigned Attribute, StringRef String) override;
377  void emitIntTextAttribute(unsigned Attribute, unsigned IntValue,
378                            StringRef StringValue) override;
379  void emitArch(unsigned Arch) override;
380  void emitObjectArch(unsigned Arch) override;
381  void emitFPU(unsigned FPU) override;
382  void emitInst(uint32_t Inst, char Suffix = '\0') override;
383  void finishAttributeSection() override;
384  void emitLabel(MCSymbol *Symbol) override;
385
386  void AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *SRE) override;
387  void emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) override;
388
389  size_t calculateContentSize() const;
390
391  // Reset state between object emissions
392  void reset() override;
393
394public:
395  ARMTargetELFStreamer(MCStreamer &S)
396    : ARMTargetStreamer(S), CurrentVendor("aeabi"), FPU(ARM::FK_INVALID),
397      Arch(ARM::AK_INVALID), EmittedArch(ARM::AK_INVALID),
398      AttributeSection(nullptr) {}
399};
400
401/// Extend the generic ELFStreamer class so that it can emit mapping symbols at
402/// the appropriate points in the object files. These symbols are defined in the
403/// ARM ELF ABI: infocenter.arm.com/help/topic/com.arm.../IHI0044D_aaelf.pdf.
404///
405/// In brief: $a, $t or $d should be emitted at the start of each contiguous
406/// region of ARM code, Thumb code or data in a section. In practice, this
407/// emission does not rely on explicit assembler directives but on inherent
408/// properties of the directives doing the emission (e.g. ".byte" is data, "add
409/// r0, r0, r0" an instruction).
410///
411/// As a result this system is orthogonal to the DataRegion infrastructure used
412/// by MachO. Beware!
413class ARMELFStreamer : public MCELFStreamer {
414public:
415  friend class ARMTargetELFStreamer;
416
417  ARMELFStreamer(MCContext &Context, MCAsmBackend &TAB, raw_pwrite_stream &OS,
418                 MCCodeEmitter *Emitter, bool IsThumb)
419      : MCELFStreamer(Context, TAB, OS, Emitter), IsThumb(IsThumb),
420        MappingSymbolCounter(0), LastEMS(EMS_None) {
421    EHReset();
422  }
423
424  ~ARMELFStreamer() {}
425
426  void FinishImpl() override;
427
428  // ARM exception handling directives
429  void emitFnStart();
430  void emitFnEnd();
431  void emitCantUnwind();
432  void emitPersonality(const MCSymbol *Per);
433  void emitPersonalityIndex(unsigned index);
434  void emitHandlerData();
435  void emitSetFP(unsigned NewFpReg, unsigned NewSpReg, int64_t Offset = 0);
436  void emitMovSP(unsigned Reg, int64_t Offset = 0);
437  void emitPad(int64_t Offset);
438  void emitRegSave(const SmallVectorImpl<unsigned> &RegList, bool isVector);
439  void emitUnwindRaw(int64_t Offset, const SmallVectorImpl<uint8_t> &Opcodes);
440
441  void ChangeSection(MCSection *Section, const MCExpr *Subsection) override {
442    // We have to keep track of the mapping symbol state of any sections we
443    // use. Each one should start off as EMS_None, which is provided as the
444    // default constructor by DenseMap::lookup.
445    LastMappingSymbols[getPreviousSection().first] = LastEMS;
446    LastEMS = LastMappingSymbols.lookup(Section);
447
448    MCELFStreamer::ChangeSection(Section, Subsection);
449  }
450
451  /// This function is the one used to emit instruction data into the ELF
452  /// streamer. We override it to add the appropriate mapping symbol if
453  /// necessary.
454  void EmitInstruction(const MCInst& Inst,
455                       const MCSubtargetInfo &STI) override {
456    if (IsThumb)
457      EmitThumbMappingSymbol();
458    else
459      EmitARMMappingSymbol();
460
461    MCELFStreamer::EmitInstruction(Inst, STI);
462  }
463
464  void emitInst(uint32_t Inst, char Suffix) {
465    unsigned Size;
466    char Buffer[4];
467    const bool LittleEndian = getContext().getAsmInfo()->isLittleEndian();
468
469    switch (Suffix) {
470    case '\0':
471      Size = 4;
472
473      assert(!IsThumb);
474      EmitARMMappingSymbol();
475      for (unsigned II = 0, IE = Size; II != IE; II++) {
476        const unsigned I = LittleEndian ? (Size - II - 1) : II;
477        Buffer[Size - II - 1] = uint8_t(Inst >> I * CHAR_BIT);
478      }
479
480      break;
481    case 'n':
482    case 'w':
483      Size = (Suffix == 'n' ? 2 : 4);
484
485      assert(IsThumb);
486      EmitThumbMappingSymbol();
487      for (unsigned II = 0, IE = Size; II != IE; II = II + 2) {
488        const unsigned I0 = LittleEndian ? II + 0 : (Size - II - 1);
489        const unsigned I1 = LittleEndian ? II + 1 : (Size - II - 2);
490        Buffer[Size - II - 2] = uint8_t(Inst >> I0 * CHAR_BIT);
491        Buffer[Size - II - 1] = uint8_t(Inst >> I1 * CHAR_BIT);
492      }
493
494      break;
495    default:
496      llvm_unreachable("Invalid Suffix");
497    }
498
499    MCELFStreamer::EmitBytes(StringRef(Buffer, Size));
500  }
501
502  /// This is one of the functions used to emit data into an ELF section, so the
503  /// ARM streamer overrides it to add the appropriate mapping symbol ($d) if
504  /// necessary.
505  void EmitBytes(StringRef Data) override {
506    EmitDataMappingSymbol();
507    MCELFStreamer::EmitBytes(Data);
508  }
509
510  /// This is one of the functions used to emit data into an ELF section, so the
511  /// ARM streamer overrides it to add the appropriate mapping symbol ($d) if
512  /// necessary.
513  void EmitValueImpl(const MCExpr *Value, unsigned Size, SMLoc Loc) override {
514    if (const MCSymbolRefExpr *SRE = dyn_cast_or_null<MCSymbolRefExpr>(Value))
515      if (SRE->getKind() == MCSymbolRefExpr::VK_ARM_SBREL && !(Size == 4)) {
516        getContext().reportError(Loc, "relocated expression must be 32-bit");
517        return;
518      }
519
520    EmitDataMappingSymbol();
521    MCELFStreamer::EmitValueImpl(Value, Size, Loc);
522  }
523
524  void EmitAssemblerFlag(MCAssemblerFlag Flag) override {
525    MCELFStreamer::EmitAssemblerFlag(Flag);
526
527    switch (Flag) {
528    case MCAF_SyntaxUnified:
529      return; // no-op here.
530    case MCAF_Code16:
531      IsThumb = true;
532      return; // Change to Thumb mode
533    case MCAF_Code32:
534      IsThumb = false;
535      return; // Change to ARM mode
536    case MCAF_Code64:
537      return;
538    case MCAF_SubsectionsViaSymbols:
539      return;
540    }
541  }
542
543private:
544  enum ElfMappingSymbol {
545    EMS_None,
546    EMS_ARM,
547    EMS_Thumb,
548    EMS_Data
549  };
550
551  void EmitDataMappingSymbol() {
552    if (LastEMS == EMS_Data) return;
553    EmitMappingSymbol("$d");
554    LastEMS = EMS_Data;
555  }
556
557  void EmitThumbMappingSymbol() {
558    if (LastEMS == EMS_Thumb) return;
559    EmitMappingSymbol("$t");
560    LastEMS = EMS_Thumb;
561  }
562
563  void EmitARMMappingSymbol() {
564    if (LastEMS == EMS_ARM) return;
565    EmitMappingSymbol("$a");
566    LastEMS = EMS_ARM;
567  }
568
569  void EmitMappingSymbol(StringRef Name) {
570    auto *Symbol = cast<MCSymbolELF>(getContext().getOrCreateSymbol(
571        Name + "." + Twine(MappingSymbolCounter++)));
572    EmitLabel(Symbol);
573
574    Symbol->setType(ELF::STT_NOTYPE);
575    Symbol->setBinding(ELF::STB_LOCAL);
576    Symbol->setExternal(false);
577  }
578
579  void EmitThumbFunc(MCSymbol *Func) override {
580    getAssembler().setIsThumbFunc(Func);
581    EmitSymbolAttribute(Func, MCSA_ELF_TypeFunction);
582  }
583
584  // Helper functions for ARM exception handling directives
585  void EHReset();
586
587  // Reset state between object emissions
588  void reset() override;
589
590  void EmitPersonalityFixup(StringRef Name);
591  void FlushPendingOffset();
592  void FlushUnwindOpcodes(bool NoHandlerData);
593
594  void SwitchToEHSection(const char *Prefix, unsigned Type, unsigned Flags,
595                         SectionKind Kind, const MCSymbol &Fn);
596  void SwitchToExTabSection(const MCSymbol &FnStart);
597  void SwitchToExIdxSection(const MCSymbol &FnStart);
598
599  void EmitFixup(const MCExpr *Expr, MCFixupKind Kind);
600
601  bool IsThumb;
602  int64_t MappingSymbolCounter;
603
604  DenseMap<const MCSection *, ElfMappingSymbol> LastMappingSymbols;
605  ElfMappingSymbol LastEMS;
606
607  // ARM Exception Handling Frame Information
608  MCSymbol *ExTab;
609  MCSymbol *FnStart;
610  const MCSymbol *Personality;
611  unsigned PersonalityIndex;
612  unsigned FPReg; // Frame pointer register
613  int64_t FPOffset; // Offset: (final frame pointer) - (initial $sp)
614  int64_t SPOffset; // Offset: (final $sp) - (initial $sp)
615  int64_t PendingOffset; // Offset: (final $sp) - (emitted $sp)
616  bool UsedFP;
617  bool CantUnwind;
618  SmallVector<uint8_t, 64> Opcodes;
619  UnwindOpcodeAssembler UnwindOpAsm;
620};
621} // end anonymous namespace
622
623ARMELFStreamer &ARMTargetELFStreamer::getStreamer() {
624  return static_cast<ARMELFStreamer &>(Streamer);
625}
626
627void ARMTargetELFStreamer::emitFnStart() { getStreamer().emitFnStart(); }
628void ARMTargetELFStreamer::emitFnEnd() { getStreamer().emitFnEnd(); }
629void ARMTargetELFStreamer::emitCantUnwind() { getStreamer().emitCantUnwind(); }
630void ARMTargetELFStreamer::emitPersonality(const MCSymbol *Personality) {
631  getStreamer().emitPersonality(Personality);
632}
633void ARMTargetELFStreamer::emitPersonalityIndex(unsigned Index) {
634  getStreamer().emitPersonalityIndex(Index);
635}
636void ARMTargetELFStreamer::emitHandlerData() {
637  getStreamer().emitHandlerData();
638}
639void ARMTargetELFStreamer::emitSetFP(unsigned FpReg, unsigned SpReg,
640                                     int64_t Offset) {
641  getStreamer().emitSetFP(FpReg, SpReg, Offset);
642}
643void ARMTargetELFStreamer::emitMovSP(unsigned Reg, int64_t Offset) {
644  getStreamer().emitMovSP(Reg, Offset);
645}
646void ARMTargetELFStreamer::emitPad(int64_t Offset) {
647  getStreamer().emitPad(Offset);
648}
649void ARMTargetELFStreamer::emitRegSave(const SmallVectorImpl<unsigned> &RegList,
650                                       bool isVector) {
651  getStreamer().emitRegSave(RegList, isVector);
652}
653void ARMTargetELFStreamer::emitUnwindRaw(int64_t Offset,
654                                      const SmallVectorImpl<uint8_t> &Opcodes) {
655  getStreamer().emitUnwindRaw(Offset, Opcodes);
656}
657void ARMTargetELFStreamer::switchVendor(StringRef Vendor) {
658  assert(!Vendor.empty() && "Vendor cannot be empty.");
659
660  if (CurrentVendor == Vendor)
661    return;
662
663  if (!CurrentVendor.empty())
664    finishAttributeSection();
665
666  assert(Contents.empty() &&
667         ".ARM.attributes should be flushed before changing vendor");
668  CurrentVendor = Vendor;
669
670}
671void ARMTargetELFStreamer::emitAttribute(unsigned Attribute, unsigned Value) {
672  setAttributeItem(Attribute, Value, /* OverwriteExisting= */ true);
673}
674void ARMTargetELFStreamer::emitTextAttribute(unsigned Attribute,
675                                             StringRef Value) {
676  setAttributeItem(Attribute, Value, /* OverwriteExisting= */ true);
677}
678void ARMTargetELFStreamer::emitIntTextAttribute(unsigned Attribute,
679                                                unsigned IntValue,
680                                                StringRef StringValue) {
681  setAttributeItems(Attribute, IntValue, StringValue,
682                    /* OverwriteExisting= */ true);
683}
684void ARMTargetELFStreamer::emitArch(unsigned Value) {
685  Arch = Value;
686}
687void ARMTargetELFStreamer::emitObjectArch(unsigned Value) {
688  EmittedArch = Value;
689}
690void ARMTargetELFStreamer::emitArchDefaultAttributes() {
691  using namespace ARMBuildAttrs;
692
693  setAttributeItem(CPU_name,
694                   ARM::getCPUAttr(Arch),
695                   false);
696
697  if (EmittedArch == ARM::AK_INVALID)
698    setAttributeItem(CPU_arch,
699                     ARM::getArchAttr(Arch),
700                     false);
701  else
702    setAttributeItem(CPU_arch,
703                     ARM::getArchAttr(EmittedArch),
704                     false);
705
706  switch (Arch) {
707  case ARM::AK_ARMV2:
708  case ARM::AK_ARMV2A:
709  case ARM::AK_ARMV3:
710  case ARM::AK_ARMV3M:
711  case ARM::AK_ARMV4:
712    setAttributeItem(ARM_ISA_use, Allowed, false);
713    break;
714
715  case ARM::AK_ARMV4T:
716  case ARM::AK_ARMV5T:
717  case ARM::AK_ARMV5TE:
718  case ARM::AK_ARMV6:
719    setAttributeItem(ARM_ISA_use, Allowed, false);
720    setAttributeItem(THUMB_ISA_use, Allowed, false);
721    break;
722
723  case ARM::AK_ARMV6T2:
724    setAttributeItem(ARM_ISA_use, Allowed, false);
725    setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
726    break;
727
728  case ARM::AK_ARMV6K:
729  case ARM::AK_ARMV6KZ:
730    setAttributeItem(ARM_ISA_use, Allowed, false);
731    setAttributeItem(THUMB_ISA_use, Allowed, false);
732    setAttributeItem(Virtualization_use, AllowTZ, false);
733    break;
734
735  case ARM::AK_ARMV6M:
736    setAttributeItem(THUMB_ISA_use, Allowed, false);
737    break;
738
739  case ARM::AK_ARMV7A:
740    setAttributeItem(CPU_arch_profile, ApplicationProfile, false);
741    setAttributeItem(ARM_ISA_use, Allowed, false);
742    setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
743    break;
744
745  case ARM::AK_ARMV7R:
746    setAttributeItem(CPU_arch_profile, RealTimeProfile, false);
747    setAttributeItem(ARM_ISA_use, Allowed, false);
748    setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
749    break;
750
751  case ARM::AK_ARMV7M:
752    setAttributeItem(CPU_arch_profile, MicroControllerProfile, false);
753    setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
754    break;
755
756  case ARM::AK_ARMV8A:
757  case ARM::AK_ARMV8_1A:
758  case ARM::AK_ARMV8_2A:
759    setAttributeItem(CPU_arch_profile, ApplicationProfile, false);
760    setAttributeItem(ARM_ISA_use, Allowed, false);
761    setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
762    setAttributeItem(MPextension_use, Allowed, false);
763    setAttributeItem(Virtualization_use, AllowTZVirtualization, false);
764    break;
765
766  case ARM::AK_ARMV8MBaseline:
767  case ARM::AK_ARMV8MMainline:
768    setAttributeItem(THUMB_ISA_use, AllowThumbDerived, false);
769    setAttributeItem(CPU_arch_profile, MicroControllerProfile, false);
770    break;
771
772  case ARM::AK_IWMMXT:
773    setAttributeItem(ARM_ISA_use, Allowed, false);
774    setAttributeItem(THUMB_ISA_use, Allowed, false);
775    setAttributeItem(WMMX_arch, AllowWMMXv1, false);
776    break;
777
778  case ARM::AK_IWMMXT2:
779    setAttributeItem(ARM_ISA_use, Allowed, false);
780    setAttributeItem(THUMB_ISA_use, Allowed, false);
781    setAttributeItem(WMMX_arch, AllowWMMXv2, false);
782    break;
783
784  default:
785    report_fatal_error("Unknown Arch: " + Twine(Arch));
786    break;
787  }
788}
789void ARMTargetELFStreamer::emitFPU(unsigned Value) {
790  FPU = Value;
791}
792void ARMTargetELFStreamer::emitFPUDefaultAttributes() {
793  switch (FPU) {
794  case ARM::FK_VFP:
795  case ARM::FK_VFPV2:
796    setAttributeItem(ARMBuildAttrs::FP_arch,
797                     ARMBuildAttrs::AllowFPv2,
798                     /* OverwriteExisting= */ false);
799    break;
800
801  case ARM::FK_VFPV3:
802    setAttributeItem(ARMBuildAttrs::FP_arch,
803                     ARMBuildAttrs::AllowFPv3A,
804                     /* OverwriteExisting= */ false);
805    break;
806
807  case ARM::FK_VFPV3_FP16:
808    setAttributeItem(ARMBuildAttrs::FP_arch,
809                     ARMBuildAttrs::AllowFPv3A,
810                     /* OverwriteExisting= */ false);
811    setAttributeItem(ARMBuildAttrs::FP_HP_extension,
812                     ARMBuildAttrs::AllowHPFP,
813                     /* OverwriteExisting= */ false);
814    break;
815
816  case ARM::FK_VFPV3_D16:
817    setAttributeItem(ARMBuildAttrs::FP_arch,
818                     ARMBuildAttrs::AllowFPv3B,
819                     /* OverwriteExisting= */ false);
820    break;
821
822  case ARM::FK_VFPV3_D16_FP16:
823    setAttributeItem(ARMBuildAttrs::FP_arch,
824                     ARMBuildAttrs::AllowFPv3B,
825                     /* OverwriteExisting= */ false);
826    setAttributeItem(ARMBuildAttrs::FP_HP_extension,
827                     ARMBuildAttrs::AllowHPFP,
828                     /* OverwriteExisting= */ false);
829    break;
830
831  case ARM::FK_VFPV3XD:
832    setAttributeItem(ARMBuildAttrs::FP_arch,
833                     ARMBuildAttrs::AllowFPv3B,
834                     /* OverwriteExisting= */ false);
835    break;
836  case ARM::FK_VFPV3XD_FP16:
837    setAttributeItem(ARMBuildAttrs::FP_arch,
838                     ARMBuildAttrs::AllowFPv3B,
839                     /* OverwriteExisting= */ false);
840    setAttributeItem(ARMBuildAttrs::FP_HP_extension,
841                     ARMBuildAttrs::AllowHPFP,
842                     /* OverwriteExisting= */ false);
843    break;
844
845  case ARM::FK_VFPV4:
846    setAttributeItem(ARMBuildAttrs::FP_arch,
847                     ARMBuildAttrs::AllowFPv4A,
848                     /* OverwriteExisting= */ false);
849    break;
850
851  // ABI_HardFP_use is handled in ARMAsmPrinter, so _SP_D16 is treated the same
852  // as _D16 here.
853  case ARM::FK_FPV4_SP_D16:
854  case ARM::FK_VFPV4_D16:
855    setAttributeItem(ARMBuildAttrs::FP_arch,
856                     ARMBuildAttrs::AllowFPv4B,
857                     /* OverwriteExisting= */ false);
858    break;
859
860  case ARM::FK_FP_ARMV8:
861    setAttributeItem(ARMBuildAttrs::FP_arch,
862                     ARMBuildAttrs::AllowFPARMv8A,
863                     /* OverwriteExisting= */ false);
864    break;
865
866  // FPV5_D16 is identical to FP_ARMV8 except for the number of D registers, so
867  // uses the FP_ARMV8_D16 build attribute.
868  case ARM::FK_FPV5_SP_D16:
869  case ARM::FK_FPV5_D16:
870    setAttributeItem(ARMBuildAttrs::FP_arch,
871                     ARMBuildAttrs::AllowFPARMv8B,
872                     /* OverwriteExisting= */ false);
873    break;
874
875  case ARM::FK_NEON:
876    setAttributeItem(ARMBuildAttrs::FP_arch,
877                     ARMBuildAttrs::AllowFPv3A,
878                     /* OverwriteExisting= */ false);
879    setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
880                     ARMBuildAttrs::AllowNeon,
881                     /* OverwriteExisting= */ false);
882    break;
883
884  case ARM::FK_NEON_FP16:
885    setAttributeItem(ARMBuildAttrs::FP_arch,
886                     ARMBuildAttrs::AllowFPv3A,
887                     /* OverwriteExisting= */ false);
888    setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
889                     ARMBuildAttrs::AllowNeon,
890                     /* OverwriteExisting= */ false);
891    setAttributeItem(ARMBuildAttrs::FP_HP_extension,
892                     ARMBuildAttrs::AllowHPFP,
893                     /* OverwriteExisting= */ false);
894    break;
895
896  case ARM::FK_NEON_VFPV4:
897    setAttributeItem(ARMBuildAttrs::FP_arch,
898                     ARMBuildAttrs::AllowFPv4A,
899                     /* OverwriteExisting= */ false);
900    setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
901                     ARMBuildAttrs::AllowNeon2,
902                     /* OverwriteExisting= */ false);
903    break;
904
905  case ARM::FK_NEON_FP_ARMV8:
906  case ARM::FK_CRYPTO_NEON_FP_ARMV8:
907    setAttributeItem(ARMBuildAttrs::FP_arch,
908                     ARMBuildAttrs::AllowFPARMv8A,
909                     /* OverwriteExisting= */ false);
910    // 'Advanced_SIMD_arch' must be emitted not here, but within
911    // ARMAsmPrinter::emitAttributes(), depending on hasV8Ops() and hasV8_1a()
912    break;
913
914  case ARM::FK_SOFTVFP:
915  case ARM::FK_NONE:
916    break;
917
918  default:
919    report_fatal_error("Unknown FPU: " + Twine(FPU));
920    break;
921  }
922}
923size_t ARMTargetELFStreamer::calculateContentSize() const {
924  size_t Result = 0;
925  for (size_t i = 0; i < Contents.size(); ++i) {
926    AttributeItem item = Contents[i];
927    switch (item.Type) {
928    case AttributeItem::HiddenAttribute:
929      break;
930    case AttributeItem::NumericAttribute:
931      Result += getULEB128Size(item.Tag);
932      Result += getULEB128Size(item.IntValue);
933      break;
934    case AttributeItem::TextAttribute:
935      Result += getULEB128Size(item.Tag);
936      Result += item.StringValue.size() + 1; // string + '\0'
937      break;
938    case AttributeItem::NumericAndTextAttributes:
939      Result += getULEB128Size(item.Tag);
940      Result += getULEB128Size(item.IntValue);
941      Result += item.StringValue.size() + 1; // string + '\0';
942      break;
943    }
944  }
945  return Result;
946}
947void ARMTargetELFStreamer::finishAttributeSection() {
948  // <format-version>
949  // [ <section-length> "vendor-name"
950  // [ <file-tag> <size> <attribute>*
951  //   | <section-tag> <size> <section-number>* 0 <attribute>*
952  //   | <symbol-tag> <size> <symbol-number>* 0 <attribute>*
953  //   ]+
954  // ]*
955
956  if (FPU != ARM::FK_INVALID)
957    emitFPUDefaultAttributes();
958
959  if (Arch != ARM::AK_INVALID)
960    emitArchDefaultAttributes();
961
962  if (Contents.empty())
963    return;
964
965  std::sort(Contents.begin(), Contents.end(), AttributeItem::LessTag);
966
967  ARMELFStreamer &Streamer = getStreamer();
968
969  // Switch to .ARM.attributes section
970  if (AttributeSection) {
971    Streamer.SwitchSection(AttributeSection);
972  } else {
973    AttributeSection = Streamer.getContext().getELFSection(
974        ".ARM.attributes", ELF::SHT_ARM_ATTRIBUTES, 0);
975    Streamer.SwitchSection(AttributeSection);
976
977    // Format version
978    Streamer.EmitIntValue(0x41, 1);
979  }
980
981  // Vendor size + Vendor name + '\0'
982  const size_t VendorHeaderSize = 4 + CurrentVendor.size() + 1;
983
984  // Tag + Tag Size
985  const size_t TagHeaderSize = 1 + 4;
986
987  const size_t ContentsSize = calculateContentSize();
988
989  Streamer.EmitIntValue(VendorHeaderSize + TagHeaderSize + ContentsSize, 4);
990  Streamer.EmitBytes(CurrentVendor);
991  Streamer.EmitIntValue(0, 1); // '\0'
992
993  Streamer.EmitIntValue(ARMBuildAttrs::File, 1);
994  Streamer.EmitIntValue(TagHeaderSize + ContentsSize, 4);
995
996  // Size should have been accounted for already, now
997  // emit each field as its type (ULEB or String)
998  for (size_t i = 0; i < Contents.size(); ++i) {
999    AttributeItem item = Contents[i];
1000    Streamer.EmitULEB128IntValue(item.Tag);
1001    switch (item.Type) {
1002    default: llvm_unreachable("Invalid attribute type");
1003    case AttributeItem::NumericAttribute:
1004      Streamer.EmitULEB128IntValue(item.IntValue);
1005      break;
1006    case AttributeItem::TextAttribute:
1007      Streamer.EmitBytes(item.StringValue);
1008      Streamer.EmitIntValue(0, 1); // '\0'
1009      break;
1010    case AttributeItem::NumericAndTextAttributes:
1011      Streamer.EmitULEB128IntValue(item.IntValue);
1012      Streamer.EmitBytes(item.StringValue);
1013      Streamer.EmitIntValue(0, 1); // '\0'
1014      break;
1015    }
1016  }
1017
1018  Contents.clear();
1019  FPU = ARM::FK_INVALID;
1020}
1021
1022void ARMTargetELFStreamer::emitLabel(MCSymbol *Symbol) {
1023  ARMELFStreamer &Streamer = getStreamer();
1024  if (!Streamer.IsThumb)
1025    return;
1026
1027  Streamer.getAssembler().registerSymbol(*Symbol);
1028  unsigned Type = cast<MCSymbolELF>(Symbol)->getType();
1029  if (Type == ELF::STT_FUNC || Type == ELF::STT_GNU_IFUNC)
1030    Streamer.EmitThumbFunc(Symbol);
1031}
1032
1033void
1034ARMTargetELFStreamer::AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *S) {
1035  getStreamer().EmitFixup(S, FK_Data_4);
1036}
1037
1038void ARMTargetELFStreamer::emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) {
1039  if (const MCSymbolRefExpr *SRE = dyn_cast<MCSymbolRefExpr>(Value)) {
1040    const MCSymbol &Sym = SRE->getSymbol();
1041    if (!Sym.isDefined()) {
1042      getStreamer().EmitAssignment(Symbol, Value);
1043      return;
1044    }
1045  }
1046
1047  getStreamer().EmitThumbFunc(Symbol);
1048  getStreamer().EmitAssignment(Symbol, Value);
1049}
1050
1051void ARMTargetELFStreamer::emitInst(uint32_t Inst, char Suffix) {
1052  getStreamer().emitInst(Inst, Suffix);
1053}
1054
1055void ARMTargetELFStreamer::reset() { AttributeSection = nullptr; }
1056
1057void ARMELFStreamer::FinishImpl() {
1058  MCTargetStreamer &TS = *getTargetStreamer();
1059  ARMTargetStreamer &ATS = static_cast<ARMTargetStreamer &>(TS);
1060  ATS.finishAttributeSection();
1061
1062  MCELFStreamer::FinishImpl();
1063}
1064
1065void ARMELFStreamer::reset() {
1066  MCTargetStreamer &TS = *getTargetStreamer();
1067  ARMTargetStreamer &ATS = static_cast<ARMTargetStreamer &>(TS);
1068  ATS.reset();
1069  MappingSymbolCounter = 0;
1070  MCELFStreamer::reset();
1071  // MCELFStreamer clear's the assembler's e_flags. However, for
1072  // arm we manually set the ABI version on streamer creation, so
1073  // do the same here
1074  getAssembler().setELFHeaderEFlags(ELF::EF_ARM_EABI_VER5);
1075}
1076
1077inline void ARMELFStreamer::SwitchToEHSection(const char *Prefix,
1078                                              unsigned Type,
1079                                              unsigned Flags,
1080                                              SectionKind Kind,
1081                                              const MCSymbol &Fn) {
1082  const MCSectionELF &FnSection =
1083    static_cast<const MCSectionELF &>(Fn.getSection());
1084
1085  // Create the name for new section
1086  StringRef FnSecName(FnSection.getSectionName());
1087  SmallString<128> EHSecName(Prefix);
1088  if (FnSecName != ".text") {
1089    EHSecName += FnSecName;
1090  }
1091
1092  // Get .ARM.extab or .ARM.exidx section
1093  const MCSymbolELF *Group = FnSection.getGroup();
1094  if (Group)
1095    Flags |= ELF::SHF_GROUP;
1096  MCSectionELF *EHSection =
1097      getContext().getELFSection(EHSecName, Type, Flags, 0, Group,
1098                                 FnSection.getUniqueID(), nullptr, &FnSection);
1099
1100  assert(EHSection && "Failed to get the required EH section");
1101
1102  // Switch to .ARM.extab or .ARM.exidx section
1103  SwitchSection(EHSection);
1104  EmitCodeAlignment(4);
1105}
1106
1107inline void ARMELFStreamer::SwitchToExTabSection(const MCSymbol &FnStart) {
1108  SwitchToEHSection(".ARM.extab", ELF::SHT_PROGBITS, ELF::SHF_ALLOC,
1109                    SectionKind::getData(), FnStart);
1110}
1111
1112inline void ARMELFStreamer::SwitchToExIdxSection(const MCSymbol &FnStart) {
1113  SwitchToEHSection(".ARM.exidx", ELF::SHT_ARM_EXIDX,
1114                    ELF::SHF_ALLOC | ELF::SHF_LINK_ORDER,
1115                    SectionKind::getData(), FnStart);
1116}
1117void ARMELFStreamer::EmitFixup(const MCExpr *Expr, MCFixupKind Kind) {
1118  MCDataFragment *Frag = getOrCreateDataFragment();
1119  Frag->getFixups().push_back(MCFixup::create(Frag->getContents().size(), Expr,
1120                                              Kind));
1121}
1122
1123void ARMELFStreamer::EHReset() {
1124  ExTab = nullptr;
1125  FnStart = nullptr;
1126  Personality = nullptr;
1127  PersonalityIndex = ARM::EHABI::NUM_PERSONALITY_INDEX;
1128  FPReg = ARM::SP;
1129  FPOffset = 0;
1130  SPOffset = 0;
1131  PendingOffset = 0;
1132  UsedFP = false;
1133  CantUnwind = false;
1134
1135  Opcodes.clear();
1136  UnwindOpAsm.Reset();
1137}
1138
1139void ARMELFStreamer::emitFnStart() {
1140  assert(FnStart == nullptr);
1141  FnStart = getContext().createTempSymbol();
1142  EmitLabel(FnStart);
1143}
1144
1145void ARMELFStreamer::emitFnEnd() {
1146  assert(FnStart && ".fnstart must precedes .fnend");
1147
1148  // Emit unwind opcodes if there is no .handlerdata directive
1149  if (!ExTab && !CantUnwind)
1150    FlushUnwindOpcodes(true);
1151
1152  // Emit the exception index table entry
1153  SwitchToExIdxSection(*FnStart);
1154
1155  if (PersonalityIndex < ARM::EHABI::NUM_PERSONALITY_INDEX)
1156    EmitPersonalityFixup(GetAEABIUnwindPersonalityName(PersonalityIndex));
1157
1158  const MCSymbolRefExpr *FnStartRef =
1159    MCSymbolRefExpr::create(FnStart,
1160                            MCSymbolRefExpr::VK_ARM_PREL31,
1161                            getContext());
1162
1163  EmitValue(FnStartRef, 4);
1164
1165  if (CantUnwind) {
1166    EmitIntValue(ARM::EHABI::EXIDX_CANTUNWIND, 4);
1167  } else if (ExTab) {
1168    // Emit a reference to the unwind opcodes in the ".ARM.extab" section.
1169    const MCSymbolRefExpr *ExTabEntryRef =
1170      MCSymbolRefExpr::create(ExTab,
1171                              MCSymbolRefExpr::VK_ARM_PREL31,
1172                              getContext());
1173    EmitValue(ExTabEntryRef, 4);
1174  } else {
1175    // For the __aeabi_unwind_cpp_pr0, we have to emit the unwind opcodes in
1176    // the second word of exception index table entry.  The size of the unwind
1177    // opcodes should always be 4 bytes.
1178    assert(PersonalityIndex == ARM::EHABI::AEABI_UNWIND_CPP_PR0 &&
1179           "Compact model must use __aeabi_unwind_cpp_pr0 as personality");
1180    assert(Opcodes.size() == 4u &&
1181           "Unwind opcode size for __aeabi_unwind_cpp_pr0 must be equal to 4");
1182    uint64_t Intval = Opcodes[0] |
1183                      Opcodes[1] << 8 |
1184                      Opcodes[2] << 16 |
1185                      Opcodes[3] << 24;
1186    EmitIntValue(Intval, Opcodes.size());
1187  }
1188
1189  // Switch to the section containing FnStart
1190  SwitchSection(&FnStart->getSection());
1191
1192  // Clean exception handling frame information
1193  EHReset();
1194}
1195
1196void ARMELFStreamer::emitCantUnwind() { CantUnwind = true; }
1197
1198// Add the R_ARM_NONE fixup at the same position
1199void ARMELFStreamer::EmitPersonalityFixup(StringRef Name) {
1200  const MCSymbol *PersonalitySym = getContext().getOrCreateSymbol(Name);
1201
1202  const MCSymbolRefExpr *PersonalityRef = MCSymbolRefExpr::create(
1203      PersonalitySym, MCSymbolRefExpr::VK_ARM_NONE, getContext());
1204
1205  visitUsedExpr(*PersonalityRef);
1206  MCDataFragment *DF = getOrCreateDataFragment();
1207  DF->getFixups().push_back(MCFixup::create(DF->getContents().size(),
1208                                            PersonalityRef,
1209                                            MCFixup::getKindForSize(4, false)));
1210}
1211
1212void ARMELFStreamer::FlushPendingOffset() {
1213  if (PendingOffset != 0) {
1214    UnwindOpAsm.EmitSPOffset(-PendingOffset);
1215    PendingOffset = 0;
1216  }
1217}
1218
1219void ARMELFStreamer::FlushUnwindOpcodes(bool NoHandlerData) {
1220  // Emit the unwind opcode to restore $sp.
1221  if (UsedFP) {
1222    const MCRegisterInfo *MRI = getContext().getRegisterInfo();
1223    int64_t LastRegSaveSPOffset = SPOffset - PendingOffset;
1224    UnwindOpAsm.EmitSPOffset(LastRegSaveSPOffset - FPOffset);
1225    UnwindOpAsm.EmitSetSP(MRI->getEncodingValue(FPReg));
1226  } else {
1227    FlushPendingOffset();
1228  }
1229
1230  // Finalize the unwind opcode sequence
1231  UnwindOpAsm.Finalize(PersonalityIndex, Opcodes);
1232
1233  // For compact model 0, we have to emit the unwind opcodes in the .ARM.exidx
1234  // section.  Thus, we don't have to create an entry in the .ARM.extab
1235  // section.
1236  if (NoHandlerData && PersonalityIndex == ARM::EHABI::AEABI_UNWIND_CPP_PR0)
1237    return;
1238
1239  // Switch to .ARM.extab section.
1240  SwitchToExTabSection(*FnStart);
1241
1242  // Create .ARM.extab label for offset in .ARM.exidx
1243  assert(!ExTab);
1244  ExTab = getContext().createTempSymbol();
1245  EmitLabel(ExTab);
1246
1247  // Emit personality
1248  if (Personality) {
1249    const MCSymbolRefExpr *PersonalityRef =
1250      MCSymbolRefExpr::create(Personality,
1251                              MCSymbolRefExpr::VK_ARM_PREL31,
1252                              getContext());
1253
1254    EmitValue(PersonalityRef, 4);
1255  }
1256
1257  // Emit unwind opcodes
1258  assert((Opcodes.size() % 4) == 0 &&
1259         "Unwind opcode size for __aeabi_cpp_unwind_pr0 must be multiple of 4");
1260  for (unsigned I = 0; I != Opcodes.size(); I += 4) {
1261    uint64_t Intval = Opcodes[I] |
1262                      Opcodes[I + 1] << 8 |
1263                      Opcodes[I + 2] << 16 |
1264                      Opcodes[I + 3] << 24;
1265    EmitIntValue(Intval, 4);
1266  }
1267
1268  // According to ARM EHABI section 9.2, if the __aeabi_unwind_cpp_pr1() or
1269  // __aeabi_unwind_cpp_pr2() is used, then the handler data must be emitted
1270  // after the unwind opcodes.  The handler data consists of several 32-bit
1271  // words, and should be terminated by zero.
1272  //
1273  // In case that the .handlerdata directive is not specified by the
1274  // programmer, we should emit zero to terminate the handler data.
1275  if (NoHandlerData && !Personality)
1276    EmitIntValue(0, 4);
1277}
1278
1279void ARMELFStreamer::emitHandlerData() { FlushUnwindOpcodes(false); }
1280
1281void ARMELFStreamer::emitPersonality(const MCSymbol *Per) {
1282  Personality = Per;
1283  UnwindOpAsm.setPersonality(Per);
1284}
1285
1286void ARMELFStreamer::emitPersonalityIndex(unsigned Index) {
1287  assert(Index < ARM::EHABI::NUM_PERSONALITY_INDEX && "invalid index");
1288  PersonalityIndex = Index;
1289}
1290
1291void ARMELFStreamer::emitSetFP(unsigned NewFPReg, unsigned NewSPReg,
1292                               int64_t Offset) {
1293  assert((NewSPReg == ARM::SP || NewSPReg == FPReg) &&
1294         "the operand of .setfp directive should be either $sp or $fp");
1295
1296  UsedFP = true;
1297  FPReg = NewFPReg;
1298
1299  if (NewSPReg == ARM::SP)
1300    FPOffset = SPOffset + Offset;
1301  else
1302    FPOffset += Offset;
1303}
1304
1305void ARMELFStreamer::emitMovSP(unsigned Reg, int64_t Offset) {
1306  assert((Reg != ARM::SP && Reg != ARM::PC) &&
1307         "the operand of .movsp cannot be either sp or pc");
1308  assert(FPReg == ARM::SP && "current FP must be SP");
1309
1310  FlushPendingOffset();
1311
1312  FPReg = Reg;
1313  FPOffset = SPOffset + Offset;
1314
1315  const MCRegisterInfo *MRI = getContext().getRegisterInfo();
1316  UnwindOpAsm.EmitSetSP(MRI->getEncodingValue(FPReg));
1317}
1318
1319void ARMELFStreamer::emitPad(int64_t Offset) {
1320  // Track the change of the $sp offset
1321  SPOffset -= Offset;
1322
1323  // To squash multiple .pad directives, we should delay the unwind opcode
1324  // until the .save, .vsave, .handlerdata, or .fnend directives.
1325  PendingOffset -= Offset;
1326}
1327
1328void ARMELFStreamer::emitRegSave(const SmallVectorImpl<unsigned> &RegList,
1329                                 bool IsVector) {
1330  // Collect the registers in the register list
1331  unsigned Count = 0;
1332  uint32_t Mask = 0;
1333  const MCRegisterInfo *MRI = getContext().getRegisterInfo();
1334  for (size_t i = 0; i < RegList.size(); ++i) {
1335    unsigned Reg = MRI->getEncodingValue(RegList[i]);
1336    assert(Reg < (IsVector ? 32U : 16U) && "Register out of range");
1337    unsigned Bit = (1u << Reg);
1338    if ((Mask & Bit) == 0) {
1339      Mask |= Bit;
1340      ++Count;
1341    }
1342  }
1343
1344  // Track the change the $sp offset: For the .save directive, the
1345  // corresponding push instruction will decrease the $sp by (4 * Count).
1346  // For the .vsave directive, the corresponding vpush instruction will
1347  // decrease $sp by (8 * Count).
1348  SPOffset -= Count * (IsVector ? 8 : 4);
1349
1350  // Emit the opcode
1351  FlushPendingOffset();
1352  if (IsVector)
1353    UnwindOpAsm.EmitVFPRegSave(Mask);
1354  else
1355    UnwindOpAsm.EmitRegSave(Mask);
1356}
1357
1358void ARMELFStreamer::emitUnwindRaw(int64_t Offset,
1359                                   const SmallVectorImpl<uint8_t> &Opcodes) {
1360  FlushPendingOffset();
1361  SPOffset = SPOffset - Offset;
1362  UnwindOpAsm.EmitRaw(Opcodes);
1363}
1364
1365namespace llvm {
1366
1367MCTargetStreamer *createARMTargetAsmStreamer(MCStreamer &S,
1368                                             formatted_raw_ostream &OS,
1369                                             MCInstPrinter *InstPrint,
1370                                             bool isVerboseAsm) {
1371  return new ARMTargetAsmStreamer(S, OS, *InstPrint, isVerboseAsm);
1372}
1373
1374MCTargetStreamer *createARMNullTargetStreamer(MCStreamer &S) {
1375  return new ARMTargetStreamer(S);
1376}
1377
1378MCTargetStreamer *createARMObjectTargetStreamer(MCStreamer &S,
1379                                                const MCSubtargetInfo &STI) {
1380  const Triple &TT = STI.getTargetTriple();
1381  if (TT.isOSBinFormatELF())
1382    return new ARMTargetELFStreamer(S);
1383  return new ARMTargetStreamer(S);
1384}
1385
1386MCELFStreamer *createARMELFStreamer(MCContext &Context, MCAsmBackend &TAB,
1387                                    raw_pwrite_stream &OS,
1388                                    MCCodeEmitter *Emitter, bool RelaxAll,
1389                                    bool IsThumb) {
1390    ARMELFStreamer *S = new ARMELFStreamer(Context, TAB, OS, Emitter, IsThumb);
1391    // FIXME: This should eventually end up somewhere else where more
1392    // intelligent flag decisions can be made. For now we are just maintaining
1393    // the status quo for ARM and setting EF_ARM_EABI_VER5 as the default.
1394    S->getAssembler().setELFHeaderEFlags(ELF::EF_ARM_EABI_VER5);
1395
1396    if (RelaxAll)
1397      S->getAssembler().setRelaxAll(true);
1398    return S;
1399  }
1400
1401}
1402
1403
1404