ARMELFStreamer.cpp revision 288943 
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 StrinValue) 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" << ARMTargetParser::getArchName(Arch) << "\n";
199}
200void ARMTargetAsmStreamer::emitArchExtension(unsigned ArchExt) {
201  OS << "\t.arch_extension\t" << ARMTargetParser::getArchExtName(ArchExt) << "\n";
202}
203void ARMTargetAsmStreamer::emitObjectArch(unsigned Arch) {
204  OS << "\t.object_arch\t" << ARMTargetParser::getArchName(Arch) << '\n';
205}
206void ARMTargetAsmStreamer::emitFPU(unsigned FPU) {
207  OS << "\t.fpu\t" << ARMTargetParser::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 emmit 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    StringRef 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
391public:
392  ARMTargetELFStreamer(MCStreamer &S)
393    : ARMTargetStreamer(S), CurrentVendor("aeabi"), FPU(ARM::FK_INVALID),
394      Arch(ARM::AK_INVALID), EmittedArch(ARM::AK_INVALID),
395      AttributeSection(nullptr) {}
396};
397
398/// Extend the generic ELFStreamer class so that it can emit mapping symbols at
399/// the appropriate points in the object files. These symbols are defined in the
400/// ARM ELF ABI: infocenter.arm.com/help/topic/com.arm.../IHI0044D_aaelf.pdf.
401///
402/// In brief: $a, $t or $d should be emitted at the start of each contiguous
403/// region of ARM code, Thumb code or data in a section. In practice, this
404/// emission does not rely on explicit assembler directives but on inherent
405/// properties of the directives doing the emission (e.g. ".byte" is data, "add
406/// r0, r0, r0" an instruction).
407///
408/// As a result this system is orthogonal to the DataRegion infrastructure used
409/// by MachO. Beware!
410class ARMELFStreamer : public MCELFStreamer {
411public:
412  friend class ARMTargetELFStreamer;
413
414  ARMELFStreamer(MCContext &Context, MCAsmBackend &TAB, raw_pwrite_stream &OS,
415                 MCCodeEmitter *Emitter, bool IsThumb)
416      : MCELFStreamer(Context, TAB, OS, Emitter), IsThumb(IsThumb),
417        MappingSymbolCounter(0), LastEMS(EMS_None) {
418    Reset();
419  }
420
421  ~ARMELFStreamer() {}
422
423  void FinishImpl() override;
424
425  // ARM exception handling directives
426  void emitFnStart();
427  void emitFnEnd();
428  void emitCantUnwind();
429  void emitPersonality(const MCSymbol *Per);
430  void emitPersonalityIndex(unsigned index);
431  void emitHandlerData();
432  void emitSetFP(unsigned NewFpReg, unsigned NewSpReg, int64_t Offset = 0);
433  void emitMovSP(unsigned Reg, int64_t Offset = 0);
434  void emitPad(int64_t Offset);
435  void emitRegSave(const SmallVectorImpl<unsigned> &RegList, bool isVector);
436  void emitUnwindRaw(int64_t Offset, const SmallVectorImpl<uint8_t> &Opcodes);
437
438  void ChangeSection(MCSection *Section, const MCExpr *Subsection) override {
439    // We have to keep track of the mapping symbol state of any sections we
440    // use. Each one should start off as EMS_None, which is provided as the
441    // default constructor by DenseMap::lookup.
442    LastMappingSymbols[getPreviousSection().first] = LastEMS;
443    LastEMS = LastMappingSymbols.lookup(Section);
444
445    MCELFStreamer::ChangeSection(Section, Subsection);
446  }
447
448  /// This function is the one used to emit instruction data into the ELF
449  /// streamer. We override it to add the appropriate mapping symbol if
450  /// necessary.
451  void EmitInstruction(const MCInst& Inst,
452                       const MCSubtargetInfo &STI) override {
453    if (IsThumb)
454      EmitThumbMappingSymbol();
455    else
456      EmitARMMappingSymbol();
457
458    MCELFStreamer::EmitInstruction(Inst, STI);
459  }
460
461  void emitInst(uint32_t Inst, char Suffix) {
462    unsigned Size;
463    char Buffer[4];
464    const bool LittleEndian = getContext().getAsmInfo()->isLittleEndian();
465
466    switch (Suffix) {
467    case '\0':
468      Size = 4;
469
470      assert(!IsThumb);
471      EmitARMMappingSymbol();
472      for (unsigned II = 0, IE = Size; II != IE; II++) {
473        const unsigned I = LittleEndian ? (Size - II - 1) : II;
474        Buffer[Size - II - 1] = uint8_t(Inst >> I * CHAR_BIT);
475      }
476
477      break;
478    case 'n':
479    case 'w':
480      Size = (Suffix == 'n' ? 2 : 4);
481
482      assert(IsThumb);
483      EmitThumbMappingSymbol();
484      for (unsigned II = 0, IE = Size; II != IE; II = II + 2) {
485        const unsigned I0 = LittleEndian ? II + 0 : (Size - II - 1);
486        const unsigned I1 = LittleEndian ? II + 1 : (Size - II - 2);
487        Buffer[Size - II - 2] = uint8_t(Inst >> I0 * CHAR_BIT);
488        Buffer[Size - II - 1] = uint8_t(Inst >> I1 * CHAR_BIT);
489      }
490
491      break;
492    default:
493      llvm_unreachable("Invalid Suffix");
494    }
495
496    MCELFStreamer::EmitBytes(StringRef(Buffer, Size));
497  }
498
499  /// This is one of the functions used to emit data into an ELF section, so the
500  /// ARM streamer overrides it to add the appropriate mapping symbol ($d) if
501  /// necessary.
502  void EmitBytes(StringRef Data) override {
503    EmitDataMappingSymbol();
504    MCELFStreamer::EmitBytes(Data);
505  }
506
507  /// This is one of the functions used to emit data into an ELF section, so the
508  /// ARM streamer overrides it to add the appropriate mapping symbol ($d) if
509  /// necessary.
510  void EmitValueImpl(const MCExpr *Value, unsigned Size,
511                     const SMLoc &Loc) override {
512    if (const MCSymbolRefExpr *SRE = dyn_cast_or_null<MCSymbolRefExpr>(Value))
513      if (SRE->getKind() == MCSymbolRefExpr::VK_ARM_SBREL && !(Size == 4))
514        getContext().reportFatalError(Loc, "relocated expression must be 32-bit");
515
516    EmitDataMappingSymbol();
517    MCELFStreamer::EmitValueImpl(Value, Size);
518  }
519
520  void EmitAssemblerFlag(MCAssemblerFlag Flag) override {
521    MCELFStreamer::EmitAssemblerFlag(Flag);
522
523    switch (Flag) {
524    case MCAF_SyntaxUnified:
525      return; // no-op here.
526    case MCAF_Code16:
527      IsThumb = true;
528      return; // Change to Thumb mode
529    case MCAF_Code32:
530      IsThumb = false;
531      return; // Change to ARM mode
532    case MCAF_Code64:
533      return;
534    case MCAF_SubsectionsViaSymbols:
535      return;
536    }
537  }
538
539private:
540  enum ElfMappingSymbol {
541    EMS_None,
542    EMS_ARM,
543    EMS_Thumb,
544    EMS_Data
545  };
546
547  void EmitDataMappingSymbol() {
548    if (LastEMS == EMS_Data) return;
549    EmitMappingSymbol("$d");
550    LastEMS = EMS_Data;
551  }
552
553  void EmitThumbMappingSymbol() {
554    if (LastEMS == EMS_Thumb) return;
555    EmitMappingSymbol("$t");
556    LastEMS = EMS_Thumb;
557  }
558
559  void EmitARMMappingSymbol() {
560    if (LastEMS == EMS_ARM) return;
561    EmitMappingSymbol("$a");
562    LastEMS = EMS_ARM;
563  }
564
565  void EmitMappingSymbol(StringRef Name) {
566    auto *Symbol = cast<MCSymbolELF>(getContext().getOrCreateSymbol(
567        Name + "." + Twine(MappingSymbolCounter++)));
568    EmitLabel(Symbol);
569
570    Symbol->setType(ELF::STT_NOTYPE);
571    Symbol->setBinding(ELF::STB_LOCAL);
572    Symbol->setExternal(false);
573  }
574
575  void EmitThumbFunc(MCSymbol *Func) override {
576    getAssembler().setIsThumbFunc(Func);
577    EmitSymbolAttribute(Func, MCSA_ELF_TypeFunction);
578  }
579
580  // Helper functions for ARM exception handling directives
581  void Reset();
582
583  void EmitPersonalityFixup(StringRef Name);
584  void FlushPendingOffset();
585  void FlushUnwindOpcodes(bool NoHandlerData);
586
587  void SwitchToEHSection(const char *Prefix, unsigned Type, unsigned Flags,
588                         SectionKind Kind, const MCSymbol &Fn);
589  void SwitchToExTabSection(const MCSymbol &FnStart);
590  void SwitchToExIdxSection(const MCSymbol &FnStart);
591
592  void EmitFixup(const MCExpr *Expr, MCFixupKind Kind);
593
594  bool IsThumb;
595  int64_t MappingSymbolCounter;
596
597  DenseMap<const MCSection *, ElfMappingSymbol> LastMappingSymbols;
598  ElfMappingSymbol LastEMS;
599
600  // ARM Exception Handling Frame Information
601  MCSymbol *ExTab;
602  MCSymbol *FnStart;
603  const MCSymbol *Personality;
604  unsigned PersonalityIndex;
605  unsigned FPReg; // Frame pointer register
606  int64_t FPOffset; // Offset: (final frame pointer) - (initial $sp)
607  int64_t SPOffset; // Offset: (final $sp) - (initial $sp)
608  int64_t PendingOffset; // Offset: (final $sp) - (emitted $sp)
609  bool UsedFP;
610  bool CantUnwind;
611  SmallVector<uint8_t, 64> Opcodes;
612  UnwindOpcodeAssembler UnwindOpAsm;
613};
614} // end anonymous namespace
615
616ARMELFStreamer &ARMTargetELFStreamer::getStreamer() {
617  return static_cast<ARMELFStreamer &>(Streamer);
618}
619
620void ARMTargetELFStreamer::emitFnStart() { getStreamer().emitFnStart(); }
621void ARMTargetELFStreamer::emitFnEnd() { getStreamer().emitFnEnd(); }
622void ARMTargetELFStreamer::emitCantUnwind() { getStreamer().emitCantUnwind(); }
623void ARMTargetELFStreamer::emitPersonality(const MCSymbol *Personality) {
624  getStreamer().emitPersonality(Personality);
625}
626void ARMTargetELFStreamer::emitPersonalityIndex(unsigned Index) {
627  getStreamer().emitPersonalityIndex(Index);
628}
629void ARMTargetELFStreamer::emitHandlerData() {
630  getStreamer().emitHandlerData();
631}
632void ARMTargetELFStreamer::emitSetFP(unsigned FpReg, unsigned SpReg,
633                                     int64_t Offset) {
634  getStreamer().emitSetFP(FpReg, SpReg, Offset);
635}
636void ARMTargetELFStreamer::emitMovSP(unsigned Reg, int64_t Offset) {
637  getStreamer().emitMovSP(Reg, Offset);
638}
639void ARMTargetELFStreamer::emitPad(int64_t Offset) {
640  getStreamer().emitPad(Offset);
641}
642void ARMTargetELFStreamer::emitRegSave(const SmallVectorImpl<unsigned> &RegList,
643                                       bool isVector) {
644  getStreamer().emitRegSave(RegList, isVector);
645}
646void ARMTargetELFStreamer::emitUnwindRaw(int64_t Offset,
647                                      const SmallVectorImpl<uint8_t> &Opcodes) {
648  getStreamer().emitUnwindRaw(Offset, Opcodes);
649}
650void ARMTargetELFStreamer::switchVendor(StringRef Vendor) {
651  assert(!Vendor.empty() && "Vendor cannot be empty.");
652
653  if (CurrentVendor == Vendor)
654    return;
655
656  if (!CurrentVendor.empty())
657    finishAttributeSection();
658
659  assert(Contents.empty() &&
660         ".ARM.attributes should be flushed before changing vendor");
661  CurrentVendor = Vendor;
662
663}
664void ARMTargetELFStreamer::emitAttribute(unsigned Attribute, unsigned Value) {
665  setAttributeItem(Attribute, Value, /* OverwriteExisting= */ true);
666}
667void ARMTargetELFStreamer::emitTextAttribute(unsigned Attribute,
668                                             StringRef Value) {
669  setAttributeItem(Attribute, Value, /* OverwriteExisting= */ true);
670}
671void ARMTargetELFStreamer::emitIntTextAttribute(unsigned Attribute,
672                                                unsigned IntValue,
673                                                StringRef StringValue) {
674  setAttributeItems(Attribute, IntValue, StringValue,
675                    /* OverwriteExisting= */ true);
676}
677void ARMTargetELFStreamer::emitArch(unsigned Value) {
678  Arch = Value;
679}
680void ARMTargetELFStreamer::emitObjectArch(unsigned Value) {
681  EmittedArch = Value;
682}
683void ARMTargetELFStreamer::emitArchDefaultAttributes() {
684  using namespace ARMBuildAttrs;
685
686  setAttributeItem(CPU_name,
687                   ARMTargetParser::getCPUAttr(Arch),
688                   false);
689
690  if (EmittedArch == ARM::AK_INVALID)
691    setAttributeItem(CPU_arch,
692                     ARMTargetParser::getArchAttr(Arch),
693                     false);
694  else
695    setAttributeItem(CPU_arch,
696                     ARMTargetParser::getArchAttr(EmittedArch),
697                     false);
698
699  switch (Arch) {
700  case ARM::AK_ARMV2:
701  case ARM::AK_ARMV2A:
702  case ARM::AK_ARMV3:
703  case ARM::AK_ARMV3M:
704  case ARM::AK_ARMV4:
705  case ARM::AK_ARMV5:
706    setAttributeItem(ARM_ISA_use, Allowed, false);
707    break;
708
709  case ARM::AK_ARMV4T:
710  case ARM::AK_ARMV5T:
711  case ARM::AK_ARMV5TE:
712  case ARM::AK_ARMV6:
713  case ARM::AK_ARMV6J:
714    setAttributeItem(ARM_ISA_use, Allowed, false);
715    setAttributeItem(THUMB_ISA_use, Allowed, false);
716    break;
717
718  case ARM::AK_ARMV6T2:
719    setAttributeItem(ARM_ISA_use, Allowed, false);
720    setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
721    break;
722
723  case ARM::AK_ARMV6K:
724  case ARM::AK_ARMV6Z:
725  case ARM::AK_ARMV6ZK:
726    setAttributeItem(ARM_ISA_use, Allowed, false);
727    setAttributeItem(THUMB_ISA_use, Allowed, false);
728    setAttributeItem(Virtualization_use, AllowTZ, false);
729    break;
730
731  case ARM::AK_ARMV6M:
732    setAttributeItem(THUMB_ISA_use, Allowed, false);
733    break;
734
735  case ARM::AK_ARMV7:
736    setAttributeItem(THUMB_ISA_use, AllowThumb32, 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    setAttributeItem(CPU_arch_profile, ApplicationProfile, false);
759    setAttributeItem(ARM_ISA_use, Allowed, false);
760    setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
761    setAttributeItem(MPextension_use, Allowed, false);
762    setAttributeItem(Virtualization_use, AllowTZVirtualization, false);
763    break;
764
765  case ARM::AK_IWMMXT:
766    setAttributeItem(ARM_ISA_use, Allowed, false);
767    setAttributeItem(THUMB_ISA_use, Allowed, false);
768    setAttributeItem(WMMX_arch, AllowWMMXv1, false);
769    break;
770
771  case ARM::AK_IWMMXT2:
772    setAttributeItem(ARM_ISA_use, Allowed, false);
773    setAttributeItem(THUMB_ISA_use, Allowed, false);
774    setAttributeItem(WMMX_arch, AllowWMMXv2, false);
775    break;
776
777  default:
778    report_fatal_error("Unknown Arch: " + Twine(Arch));
779    break;
780  }
781}
782void ARMTargetELFStreamer::emitFPU(unsigned Value) {
783  FPU = Value;
784}
785void ARMTargetELFStreamer::emitFPUDefaultAttributes() {
786  switch (FPU) {
787  case ARM::FK_VFP:
788  case ARM::FK_VFPV2:
789    setAttributeItem(ARMBuildAttrs::FP_arch,
790                     ARMBuildAttrs::AllowFPv2,
791                     /* OverwriteExisting= */ false);
792    break;
793
794  case ARM::FK_VFPV3:
795    setAttributeItem(ARMBuildAttrs::FP_arch,
796                     ARMBuildAttrs::AllowFPv3A,
797                     /* OverwriteExisting= */ false);
798    break;
799
800  case ARM::FK_VFPV3_FP16:
801    setAttributeItem(ARMBuildAttrs::FP_arch,
802                     ARMBuildAttrs::AllowFPv3A,
803                     /* OverwriteExisting= */ false);
804    setAttributeItem(ARMBuildAttrs::FP_HP_extension,
805                     ARMBuildAttrs::AllowHPFP,
806                     /* OverwriteExisting= */ false);
807    break;
808
809  case ARM::FK_VFPV3_D16:
810    setAttributeItem(ARMBuildAttrs::FP_arch,
811                     ARMBuildAttrs::AllowFPv3B,
812                     /* OverwriteExisting= */ false);
813    break;
814
815  case ARM::FK_VFPV3_D16_FP16:
816    setAttributeItem(ARMBuildAttrs::FP_arch,
817                     ARMBuildAttrs::AllowFPv3B,
818                     /* OverwriteExisting= */ false);
819    setAttributeItem(ARMBuildAttrs::FP_HP_extension,
820                     ARMBuildAttrs::AllowHPFP,
821                     /* OverwriteExisting= */ false);
822    break;
823
824  case ARM::FK_VFPV3XD:
825    setAttributeItem(ARMBuildAttrs::FP_arch,
826                     ARMBuildAttrs::AllowFPv3B,
827                     /* OverwriteExisting= */ false);
828    break;
829  case ARM::FK_VFPV3XD_FP16:
830    setAttributeItem(ARMBuildAttrs::FP_arch,
831                     ARMBuildAttrs::AllowFPv3B,
832                     /* OverwriteExisting= */ false);
833    setAttributeItem(ARMBuildAttrs::FP_HP_extension,
834                     ARMBuildAttrs::AllowHPFP,
835                     /* OverwriteExisting= */ false);
836    break;
837
838  case ARM::FK_VFPV4:
839    setAttributeItem(ARMBuildAttrs::FP_arch,
840                     ARMBuildAttrs::AllowFPv4A,
841                     /* OverwriteExisting= */ false);
842    break;
843
844  // ABI_HardFP_use is handled in ARMAsmPrinter, so _SP_D16 is treated the same
845  // as _D16 here.
846  case ARM::FK_FPV4_SP_D16:
847  case ARM::FK_VFPV4_D16:
848    setAttributeItem(ARMBuildAttrs::FP_arch,
849                     ARMBuildAttrs::AllowFPv4B,
850                     /* OverwriteExisting= */ false);
851    break;
852
853  case ARM::FK_FP_ARMV8:
854    setAttributeItem(ARMBuildAttrs::FP_arch,
855                     ARMBuildAttrs::AllowFPARMv8A,
856                     /* OverwriteExisting= */ false);
857    break;
858
859  // FPV5_D16 is identical to FP_ARMV8 except for the number of D registers, so
860  // uses the FP_ARMV8_D16 build attribute.
861  case ARM::FK_FPV5_SP_D16:
862  case ARM::FK_FPV5_D16:
863    setAttributeItem(ARMBuildAttrs::FP_arch,
864                     ARMBuildAttrs::AllowFPARMv8B,
865                     /* OverwriteExisting= */ false);
866    break;
867
868  case ARM::FK_NEON:
869    setAttributeItem(ARMBuildAttrs::FP_arch,
870                     ARMBuildAttrs::AllowFPv3A,
871                     /* OverwriteExisting= */ false);
872    setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
873                     ARMBuildAttrs::AllowNeon,
874                     /* OverwriteExisting= */ false);
875    break;
876
877  case ARM::FK_NEON_FP16:
878    setAttributeItem(ARMBuildAttrs::FP_arch,
879                     ARMBuildAttrs::AllowFPv3A,
880                     /* OverwriteExisting= */ false);
881    setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
882                     ARMBuildAttrs::AllowNeon,
883                     /* OverwriteExisting= */ false);
884    setAttributeItem(ARMBuildAttrs::FP_HP_extension,
885                     ARMBuildAttrs::AllowHPFP,
886                     /* OverwriteExisting= */ false);
887    break;
888
889  case ARM::FK_NEON_VFPV4:
890    setAttributeItem(ARMBuildAttrs::FP_arch,
891                     ARMBuildAttrs::AllowFPv4A,
892                     /* OverwriteExisting= */ false);
893    setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
894                     ARMBuildAttrs::AllowNeon2,
895                     /* OverwriteExisting= */ false);
896    break;
897
898  case ARM::FK_NEON_FP_ARMV8:
899  case ARM::FK_CRYPTO_NEON_FP_ARMV8:
900    setAttributeItem(ARMBuildAttrs::FP_arch,
901                     ARMBuildAttrs::AllowFPARMv8A,
902                     /* OverwriteExisting= */ false);
903    // 'Advanced_SIMD_arch' must be emitted not here, but within
904    // ARMAsmPrinter::emitAttributes(), depending on hasV8Ops() and hasV8_1a()
905    break;
906
907  case ARM::FK_SOFTVFP:
908  case ARM::FK_NONE:
909    break;
910
911  default:
912    report_fatal_error("Unknown FPU: " + Twine(FPU));
913    break;
914  }
915}
916size_t ARMTargetELFStreamer::calculateContentSize() const {
917  size_t Result = 0;
918  for (size_t i = 0; i < Contents.size(); ++i) {
919    AttributeItem item = Contents[i];
920    switch (item.Type) {
921    case AttributeItem::HiddenAttribute:
922      break;
923    case AttributeItem::NumericAttribute:
924      Result += getULEB128Size(item.Tag);
925      Result += getULEB128Size(item.IntValue);
926      break;
927    case AttributeItem::TextAttribute:
928      Result += getULEB128Size(item.Tag);
929      Result += item.StringValue.size() + 1; // string + '\0'
930      break;
931    case AttributeItem::NumericAndTextAttributes:
932      Result += getULEB128Size(item.Tag);
933      Result += getULEB128Size(item.IntValue);
934      Result += item.StringValue.size() + 1; // string + '\0';
935      break;
936    }
937  }
938  return Result;
939}
940void ARMTargetELFStreamer::finishAttributeSection() {
941  // <format-version>
942  // [ <section-length> "vendor-name"
943  // [ <file-tag> <size> <attribute>*
944  //   | <section-tag> <size> <section-number>* 0 <attribute>*
945  //   | <symbol-tag> <size> <symbol-number>* 0 <attribute>*
946  //   ]+
947  // ]*
948
949  if (FPU != ARM::FK_INVALID)
950    emitFPUDefaultAttributes();
951
952  if (Arch != ARM::AK_INVALID)
953    emitArchDefaultAttributes();
954
955  if (Contents.empty())
956    return;
957
958  std::sort(Contents.begin(), Contents.end(), AttributeItem::LessTag);
959
960  ARMELFStreamer &Streamer = getStreamer();
961
962  // Switch to .ARM.attributes section
963  if (AttributeSection) {
964    Streamer.SwitchSection(AttributeSection);
965  } else {
966    AttributeSection = Streamer.getContext().getELFSection(
967        ".ARM.attributes", ELF::SHT_ARM_ATTRIBUTES, 0);
968    Streamer.SwitchSection(AttributeSection);
969
970    // Format version
971    Streamer.EmitIntValue(0x41, 1);
972  }
973
974  // Vendor size + Vendor name + '\0'
975  const size_t VendorHeaderSize = 4 + CurrentVendor.size() + 1;
976
977  // Tag + Tag Size
978  const size_t TagHeaderSize = 1 + 4;
979
980  const size_t ContentsSize = calculateContentSize();
981
982  Streamer.EmitIntValue(VendorHeaderSize + TagHeaderSize + ContentsSize, 4);
983  Streamer.EmitBytes(CurrentVendor);
984  Streamer.EmitIntValue(0, 1); // '\0'
985
986  Streamer.EmitIntValue(ARMBuildAttrs::File, 1);
987  Streamer.EmitIntValue(TagHeaderSize + ContentsSize, 4);
988
989  // Size should have been accounted for already, now
990  // emit each field as its type (ULEB or String)
991  for (size_t i = 0; i < Contents.size(); ++i) {
992    AttributeItem item = Contents[i];
993    Streamer.EmitULEB128IntValue(item.Tag);
994    switch (item.Type) {
995    default: llvm_unreachable("Invalid attribute type");
996    case AttributeItem::NumericAttribute:
997      Streamer.EmitULEB128IntValue(item.IntValue);
998      break;
999    case AttributeItem::TextAttribute:
1000      Streamer.EmitBytes(item.StringValue);
1001      Streamer.EmitIntValue(0, 1); // '\0'
1002      break;
1003    case AttributeItem::NumericAndTextAttributes:
1004      Streamer.EmitULEB128IntValue(item.IntValue);
1005      Streamer.EmitBytes(item.StringValue);
1006      Streamer.EmitIntValue(0, 1); // '\0'
1007      break;
1008    }
1009  }
1010
1011  Contents.clear();
1012  FPU = ARM::FK_INVALID;
1013}
1014
1015void ARMTargetELFStreamer::emitLabel(MCSymbol *Symbol) {
1016  ARMELFStreamer &Streamer = getStreamer();
1017  if (!Streamer.IsThumb)
1018    return;
1019
1020  Streamer.getAssembler().registerSymbol(*Symbol);
1021  unsigned Type = cast<MCSymbolELF>(Symbol)->getType();
1022  if (Type == ELF::STT_FUNC || Type == ELF::STT_GNU_IFUNC)
1023    Streamer.EmitThumbFunc(Symbol);
1024}
1025
1026void
1027ARMTargetELFStreamer::AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *S) {
1028  getStreamer().EmitFixup(S, FK_Data_4);
1029}
1030
1031void ARMTargetELFStreamer::emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) {
1032  if (const MCSymbolRefExpr *SRE = dyn_cast<MCSymbolRefExpr>(Value)) {
1033    const MCSymbol &Sym = SRE->getSymbol();
1034    if (!Sym.isDefined()) {
1035      getStreamer().EmitAssignment(Symbol, Value);
1036      return;
1037    }
1038  }
1039
1040  getStreamer().EmitThumbFunc(Symbol);
1041  getStreamer().EmitAssignment(Symbol, Value);
1042}
1043
1044void ARMTargetELFStreamer::emitInst(uint32_t Inst, char Suffix) {
1045  getStreamer().emitInst(Inst, Suffix);
1046}
1047
1048void ARMELFStreamer::FinishImpl() {
1049  MCTargetStreamer &TS = *getTargetStreamer();
1050  ARMTargetStreamer &ATS = static_cast<ARMTargetStreamer &>(TS);
1051  ATS.finishAttributeSection();
1052
1053  MCELFStreamer::FinishImpl();
1054}
1055
1056inline void ARMELFStreamer::SwitchToEHSection(const char *Prefix,
1057                                              unsigned Type,
1058                                              unsigned Flags,
1059                                              SectionKind Kind,
1060                                              const MCSymbol &Fn) {
1061  const MCSectionELF &FnSection =
1062    static_cast<const MCSectionELF &>(Fn.getSection());
1063
1064  // Create the name for new section
1065  StringRef FnSecName(FnSection.getSectionName());
1066  SmallString<128> EHSecName(Prefix);
1067  if (FnSecName != ".text") {
1068    EHSecName += FnSecName;
1069  }
1070
1071  // Get .ARM.extab or .ARM.exidx section
1072  const MCSymbolELF *Group = FnSection.getGroup();
1073  if (Group)
1074    Flags |= ELF::SHF_GROUP;
1075  MCSectionELF *EHSection =
1076      getContext().getELFSection(EHSecName, Type, Flags, 0, Group,
1077                                 FnSection.getUniqueID(), nullptr, &FnSection);
1078
1079  assert(EHSection && "Failed to get the required EH section");
1080
1081  // Switch to .ARM.extab or .ARM.exidx section
1082  SwitchSection(EHSection);
1083  EmitCodeAlignment(4);
1084}
1085
1086inline void ARMELFStreamer::SwitchToExTabSection(const MCSymbol &FnStart) {
1087  SwitchToEHSection(".ARM.extab",
1088                    ELF::SHT_PROGBITS,
1089                    ELF::SHF_ALLOC,
1090                    SectionKind::getDataRel(),
1091                    FnStart);
1092}
1093
1094inline void ARMELFStreamer::SwitchToExIdxSection(const MCSymbol &FnStart) {
1095  SwitchToEHSection(".ARM.exidx",
1096                    ELF::SHT_ARM_EXIDX,
1097                    ELF::SHF_ALLOC | ELF::SHF_LINK_ORDER,
1098                    SectionKind::getDataRel(),
1099                    FnStart);
1100}
1101void ARMELFStreamer::EmitFixup(const MCExpr *Expr, MCFixupKind Kind) {
1102  MCDataFragment *Frag = getOrCreateDataFragment();
1103  Frag->getFixups().push_back(MCFixup::create(Frag->getContents().size(), Expr,
1104                                              Kind));
1105}
1106
1107void ARMELFStreamer::Reset() {
1108  ExTab = nullptr;
1109  FnStart = nullptr;
1110  Personality = nullptr;
1111  PersonalityIndex = ARM::EHABI::NUM_PERSONALITY_INDEX;
1112  FPReg = ARM::SP;
1113  FPOffset = 0;
1114  SPOffset = 0;
1115  PendingOffset = 0;
1116  UsedFP = false;
1117  CantUnwind = false;
1118
1119  Opcodes.clear();
1120  UnwindOpAsm.Reset();
1121}
1122
1123void ARMELFStreamer::emitFnStart() {
1124  assert(FnStart == nullptr);
1125  FnStart = getContext().createTempSymbol();
1126  EmitLabel(FnStart);
1127}
1128
1129void ARMELFStreamer::emitFnEnd() {
1130  assert(FnStart && ".fnstart must precedes .fnend");
1131
1132  // Emit unwind opcodes if there is no .handlerdata directive
1133  if (!ExTab && !CantUnwind)
1134    FlushUnwindOpcodes(true);
1135
1136  // Emit the exception index table entry
1137  SwitchToExIdxSection(*FnStart);
1138
1139  if (PersonalityIndex < ARM::EHABI::NUM_PERSONALITY_INDEX)
1140    EmitPersonalityFixup(GetAEABIUnwindPersonalityName(PersonalityIndex));
1141
1142  const MCSymbolRefExpr *FnStartRef =
1143    MCSymbolRefExpr::create(FnStart,
1144                            MCSymbolRefExpr::VK_ARM_PREL31,
1145                            getContext());
1146
1147  EmitValue(FnStartRef, 4);
1148
1149  if (CantUnwind) {
1150    EmitIntValue(ARM::EHABI::EXIDX_CANTUNWIND, 4);
1151  } else if (ExTab) {
1152    // Emit a reference to the unwind opcodes in the ".ARM.extab" section.
1153    const MCSymbolRefExpr *ExTabEntryRef =
1154      MCSymbolRefExpr::create(ExTab,
1155                              MCSymbolRefExpr::VK_ARM_PREL31,
1156                              getContext());
1157    EmitValue(ExTabEntryRef, 4);
1158  } else {
1159    // For the __aeabi_unwind_cpp_pr0, we have to emit the unwind opcodes in
1160    // the second word of exception index table entry.  The size of the unwind
1161    // opcodes should always be 4 bytes.
1162    assert(PersonalityIndex == ARM::EHABI::AEABI_UNWIND_CPP_PR0 &&
1163           "Compact model must use __aeabi_unwind_cpp_pr0 as personality");
1164    assert(Opcodes.size() == 4u &&
1165           "Unwind opcode size for __aeabi_unwind_cpp_pr0 must be equal to 4");
1166    uint64_t Intval = Opcodes[0] |
1167                      Opcodes[1] << 8 |
1168                      Opcodes[2] << 16 |
1169                      Opcodes[3] << 24;
1170    EmitIntValue(Intval, Opcodes.size());
1171  }
1172
1173  // Switch to the section containing FnStart
1174  SwitchSection(&FnStart->getSection());
1175
1176  // Clean exception handling frame information
1177  Reset();
1178}
1179
1180void ARMELFStreamer::emitCantUnwind() { CantUnwind = true; }
1181
1182// Add the R_ARM_NONE fixup at the same position
1183void ARMELFStreamer::EmitPersonalityFixup(StringRef Name) {
1184  const MCSymbol *PersonalitySym = getContext().getOrCreateSymbol(Name);
1185
1186  const MCSymbolRefExpr *PersonalityRef = MCSymbolRefExpr::create(
1187      PersonalitySym, MCSymbolRefExpr::VK_ARM_NONE, getContext());
1188
1189  visitUsedExpr(*PersonalityRef);
1190  MCDataFragment *DF = getOrCreateDataFragment();
1191  DF->getFixups().push_back(MCFixup::create(DF->getContents().size(),
1192                                            PersonalityRef,
1193                                            MCFixup::getKindForSize(4, false)));
1194}
1195
1196void ARMELFStreamer::FlushPendingOffset() {
1197  if (PendingOffset != 0) {
1198    UnwindOpAsm.EmitSPOffset(-PendingOffset);
1199    PendingOffset = 0;
1200  }
1201}
1202
1203void ARMELFStreamer::FlushUnwindOpcodes(bool NoHandlerData) {
1204  // Emit the unwind opcode to restore $sp.
1205  if (UsedFP) {
1206    const MCRegisterInfo *MRI = getContext().getRegisterInfo();
1207    int64_t LastRegSaveSPOffset = SPOffset - PendingOffset;
1208    UnwindOpAsm.EmitSPOffset(LastRegSaveSPOffset - FPOffset);
1209    UnwindOpAsm.EmitSetSP(MRI->getEncodingValue(FPReg));
1210  } else {
1211    FlushPendingOffset();
1212  }
1213
1214  // Finalize the unwind opcode sequence
1215  UnwindOpAsm.Finalize(PersonalityIndex, Opcodes);
1216
1217  // For compact model 0, we have to emit the unwind opcodes in the .ARM.exidx
1218  // section.  Thus, we don't have to create an entry in the .ARM.extab
1219  // section.
1220  if (NoHandlerData && PersonalityIndex == ARM::EHABI::AEABI_UNWIND_CPP_PR0)
1221    return;
1222
1223  // Switch to .ARM.extab section.
1224  SwitchToExTabSection(*FnStart);
1225
1226  // Create .ARM.extab label for offset in .ARM.exidx
1227  assert(!ExTab);
1228  ExTab = getContext().createTempSymbol();
1229  EmitLabel(ExTab);
1230
1231  // Emit personality
1232  if (Personality) {
1233    const MCSymbolRefExpr *PersonalityRef =
1234      MCSymbolRefExpr::create(Personality,
1235                              MCSymbolRefExpr::VK_ARM_PREL31,
1236                              getContext());
1237
1238    EmitValue(PersonalityRef, 4);
1239  }
1240
1241  // Emit unwind opcodes
1242  assert((Opcodes.size() % 4) == 0 &&
1243         "Unwind opcode size for __aeabi_cpp_unwind_pr0 must be multiple of 4");
1244  for (unsigned I = 0; I != Opcodes.size(); I += 4) {
1245    uint64_t Intval = Opcodes[I] |
1246                      Opcodes[I + 1] << 8 |
1247                      Opcodes[I + 2] << 16 |
1248                      Opcodes[I + 3] << 24;
1249    EmitIntValue(Intval, 4);
1250  }
1251
1252  // According to ARM EHABI section 9.2, if the __aeabi_unwind_cpp_pr1() or
1253  // __aeabi_unwind_cpp_pr2() is used, then the handler data must be emitted
1254  // after the unwind opcodes.  The handler data consists of several 32-bit
1255  // words, and should be terminated by zero.
1256  //
1257  // In case that the .handlerdata directive is not specified by the
1258  // programmer, we should emit zero to terminate the handler data.
1259  if (NoHandlerData && !Personality)
1260    EmitIntValue(0, 4);
1261}
1262
1263void ARMELFStreamer::emitHandlerData() { FlushUnwindOpcodes(false); }
1264
1265void ARMELFStreamer::emitPersonality(const MCSymbol *Per) {
1266  Personality = Per;
1267  UnwindOpAsm.setPersonality(Per);
1268}
1269
1270void ARMELFStreamer::emitPersonalityIndex(unsigned Index) {
1271  assert(Index < ARM::EHABI::NUM_PERSONALITY_INDEX && "invalid index");
1272  PersonalityIndex = Index;
1273}
1274
1275void ARMELFStreamer::emitSetFP(unsigned NewFPReg, unsigned NewSPReg,
1276                               int64_t Offset) {
1277  assert((NewSPReg == ARM::SP || NewSPReg == FPReg) &&
1278         "the operand of .setfp directive should be either $sp or $fp");
1279
1280  UsedFP = true;
1281  FPReg = NewFPReg;
1282
1283  if (NewSPReg == ARM::SP)
1284    FPOffset = SPOffset + Offset;
1285  else
1286    FPOffset += Offset;
1287}
1288
1289void ARMELFStreamer::emitMovSP(unsigned Reg, int64_t Offset) {
1290  assert((Reg != ARM::SP && Reg != ARM::PC) &&
1291         "the operand of .movsp cannot be either sp or pc");
1292  assert(FPReg == ARM::SP && "current FP must be SP");
1293
1294  FlushPendingOffset();
1295
1296  FPReg = Reg;
1297  FPOffset = SPOffset + Offset;
1298
1299  const MCRegisterInfo *MRI = getContext().getRegisterInfo();
1300  UnwindOpAsm.EmitSetSP(MRI->getEncodingValue(FPReg));
1301}
1302
1303void ARMELFStreamer::emitPad(int64_t Offset) {
1304  // Track the change of the $sp offset
1305  SPOffset -= Offset;
1306
1307  // To squash multiple .pad directives, we should delay the unwind opcode
1308  // until the .save, .vsave, .handlerdata, or .fnend directives.
1309  PendingOffset -= Offset;
1310}
1311
1312void ARMELFStreamer::emitRegSave(const SmallVectorImpl<unsigned> &RegList,
1313                                 bool IsVector) {
1314  // Collect the registers in the register list
1315  unsigned Count = 0;
1316  uint32_t Mask = 0;
1317  const MCRegisterInfo *MRI = getContext().getRegisterInfo();
1318  for (size_t i = 0; i < RegList.size(); ++i) {
1319    unsigned Reg = MRI->getEncodingValue(RegList[i]);
1320    assert(Reg < (IsVector ? 32U : 16U) && "Register out of range");
1321    unsigned Bit = (1u << Reg);
1322    if ((Mask & Bit) == 0) {
1323      Mask |= Bit;
1324      ++Count;
1325    }
1326  }
1327
1328  // Track the change the $sp offset: For the .save directive, the
1329  // corresponding push instruction will decrease the $sp by (4 * Count).
1330  // For the .vsave directive, the corresponding vpush instruction will
1331  // decrease $sp by (8 * Count).
1332  SPOffset -= Count * (IsVector ? 8 : 4);
1333
1334  // Emit the opcode
1335  FlushPendingOffset();
1336  if (IsVector)
1337    UnwindOpAsm.EmitVFPRegSave(Mask);
1338  else
1339    UnwindOpAsm.EmitRegSave(Mask);
1340}
1341
1342void ARMELFStreamer::emitUnwindRaw(int64_t Offset,
1343                                   const SmallVectorImpl<uint8_t> &Opcodes) {
1344  FlushPendingOffset();
1345  SPOffset = SPOffset - Offset;
1346  UnwindOpAsm.EmitRaw(Opcodes);
1347}
1348
1349namespace llvm {
1350
1351MCTargetStreamer *createARMTargetAsmStreamer(MCStreamer &S,
1352                                             formatted_raw_ostream &OS,
1353                                             MCInstPrinter *InstPrint,
1354                                             bool isVerboseAsm) {
1355  return new ARMTargetAsmStreamer(S, OS, *InstPrint, isVerboseAsm);
1356}
1357
1358MCTargetStreamer *createARMNullTargetStreamer(MCStreamer &S) {
1359  return new ARMTargetStreamer(S);
1360}
1361
1362MCTargetStreamer *createARMObjectTargetStreamer(MCStreamer &S,
1363                                                const MCSubtargetInfo &STI) {
1364  const Triple &TT = STI.getTargetTriple();
1365  if (TT.isOSBinFormatELF())
1366    return new ARMTargetELFStreamer(S);
1367  return new ARMTargetStreamer(S);
1368}
1369
1370MCELFStreamer *createARMELFStreamer(MCContext &Context, MCAsmBackend &TAB,
1371                                    raw_pwrite_stream &OS,
1372                                    MCCodeEmitter *Emitter, bool RelaxAll,
1373                                    bool IsThumb) {
1374    ARMELFStreamer *S = new ARMELFStreamer(Context, TAB, OS, Emitter, IsThumb);
1375    // FIXME: This should eventually end up somewhere else where more
1376    // intelligent flag decisions can be made. For now we are just maintaining
1377    // the status quo for ARM and setting EF_ARM_EABI_VER5 as the default.
1378    S->getAssembler().setELFHeaderEFlags(ELF::EF_ARM_EABI_VER5);
1379
1380    if (RelaxAll)
1381      S->getAssembler().setRelaxAll(true);
1382    return S;
1383  }
1384
1385}
1386
1387
1388