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ARMELFStreamer.cpp
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1 //===- lib/MC/ARMELFStreamer.cpp - ELF Object Output for ARM --------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file assembles .s files and emits ARM ELF .o object files. Different
11 // from generic ELF streamer in emitting mapping symbols ($a, $t and $d) to
12 // delimit regions of data and code.
13 //
14 //===----------------------------------------------------------------------===//
15 
16 #include "ARMRegisterInfo.h"
17 #include "ARMUnwindOpAsm.h"
18 #include "llvm/ADT/DenseMap.h"
19 #include "llvm/ADT/SmallString.h"
20 #include "llvm/ADT/SmallVector.h"
21 #include "llvm/ADT/StringRef.h"
22 #include "llvm/ADT/Triple.h"
23 #include "llvm/ADT/Twine.h"
24 #include "llvm/BinaryFormat/ELF.h"
25 #include "llvm/MC/MCAsmBackend.h"
26 #include "llvm/MC/MCAsmInfo.h"
27 #include "llvm/MC/MCAssembler.h"
28 #include "llvm/MC/MCCodeEmitter.h"
29 #include "llvm/MC/MCContext.h"
30 #include "llvm/MC/MCELFStreamer.h"
31 #include "llvm/MC/MCExpr.h"
32 #include "llvm/MC/MCFixup.h"
33 #include "llvm/MC/MCFragment.h"
34 #include "llvm/MC/MCInst.h"
35 #include "llvm/MC/MCInstPrinter.h"
36 #include "llvm/MC/MCRegisterInfo.h"
37 #include "llvm/MC/MCSection.h"
38 #include "llvm/MC/MCSectionELF.h"
39 #include "llvm/MC/MCStreamer.h"
41 #include "llvm/MC/MCSymbol.h"
42 #include "llvm/MC/MCSymbolELF.h"
43 #include "llvm/MC/SectionKind.h"
45 #include "llvm/Support/ARMEHABI.h"
46 #include "llvm/Support/Casting.h"
49 #include "llvm/Support/LEB128.h"
52 #include <algorithm>
53 #include <cassert>
54 #include <climits>
55 #include <cstddef>
56 #include <cstdint>
57 #include <string>
58 
59 using namespace llvm;
60 
61 static std::string GetAEABIUnwindPersonalityName(unsigned Index) {
63  "Invalid personality index");
64  return (Twine("__aeabi_unwind_cpp_pr") + Twine(Index)).str();
65 }
66 
67 namespace {
68 
69 class ARMELFStreamer;
70 
71 class ARMTargetAsmStreamer : public ARMTargetStreamer {
73  MCInstPrinter &InstPrinter;
74  bool IsVerboseAsm;
75 
76  void emitFnStart() override;
77  void emitFnEnd() override;
78  void emitCantUnwind() override;
79  void emitPersonality(const MCSymbol *Personality) override;
80  void emitPersonalityIndex(unsigned Index) override;
81  void emitHandlerData() override;
82  void emitSetFP(unsigned FpReg, unsigned SpReg, int64_t Offset = 0) override;
83  void emitMovSP(unsigned Reg, int64_t Offset = 0) override;
84  void emitPad(int64_t Offset) override;
85  void emitRegSave(const SmallVectorImpl<unsigned> &RegList,
86  bool isVector) override;
87  void emitUnwindRaw(int64_t Offset,
88  const SmallVectorImpl<uint8_t> &Opcodes) override;
89 
90  void switchVendor(StringRef Vendor) override;
91  void emitAttribute(unsigned Attribute, unsigned Value) override;
92  void emitTextAttribute(unsigned Attribute, StringRef String) override;
93  void emitIntTextAttribute(unsigned Attribute, unsigned IntValue,
94  StringRef StringValue) override;
95  void emitArch(ARM::ArchKind Arch) override;
96  void emitArchExtension(unsigned ArchExt) override;
97  void emitObjectArch(ARM::ArchKind Arch) override;
98  void emitFPU(unsigned FPU) override;
99  void emitInst(uint32_t Inst, char Suffix = '\0') override;
100  void finishAttributeSection() override;
101 
102  void AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *SRE) override;
103  void emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) override;
104 
105 public:
106  ARMTargetAsmStreamer(MCStreamer &S, formatted_raw_ostream &OS,
107  MCInstPrinter &InstPrinter, bool VerboseAsm);
108 };
109 
110 ARMTargetAsmStreamer::ARMTargetAsmStreamer(MCStreamer &S,
112  MCInstPrinter &InstPrinter,
113  bool VerboseAsm)
114  : ARMTargetStreamer(S), OS(OS), InstPrinter(InstPrinter),
115  IsVerboseAsm(VerboseAsm) {}
116 
117 void ARMTargetAsmStreamer::emitFnStart() { OS << "\t.fnstart\n"; }
118 void ARMTargetAsmStreamer::emitFnEnd() { OS << "\t.fnend\n"; }
119 void ARMTargetAsmStreamer::emitCantUnwind() { OS << "\t.cantunwind\n"; }
120 
121 void ARMTargetAsmStreamer::emitPersonality(const MCSymbol *Personality) {
122  OS << "\t.personality " << Personality->getName() << '\n';
123 }
124 
125 void ARMTargetAsmStreamer::emitPersonalityIndex(unsigned Index) {
126  OS << "\t.personalityindex " << Index << '\n';
127 }
128 
129 void ARMTargetAsmStreamer::emitHandlerData() { OS << "\t.handlerdata\n"; }
130 
131 void ARMTargetAsmStreamer::emitSetFP(unsigned FpReg, unsigned SpReg,
132  int64_t Offset) {
133  OS << "\t.setfp\t";
134  InstPrinter.printRegName(OS, FpReg);
135  OS << ", ";
136  InstPrinter.printRegName(OS, SpReg);
137  if (Offset)
138  OS << ", #" << Offset;
139  OS << '\n';
140 }
141 
142 void ARMTargetAsmStreamer::emitMovSP(unsigned Reg, int64_t Offset) {
143  assert((Reg != ARM::SP && Reg != ARM::PC) &&
144  "the operand of .movsp cannot be either sp or pc");
145 
146  OS << "\t.movsp\t";
147  InstPrinter.printRegName(OS, Reg);
148  if (Offset)
149  OS << ", #" << Offset;
150  OS << '\n';
151 }
152 
153 void ARMTargetAsmStreamer::emitPad(int64_t Offset) {
154  OS << "\t.pad\t#" << Offset << '\n';
155 }
156 
157 void ARMTargetAsmStreamer::emitRegSave(const SmallVectorImpl<unsigned> &RegList,
158  bool isVector) {
159  assert(RegList.size() && "RegList should not be empty");
160  if (isVector)
161  OS << "\t.vsave\t{";
162  else
163  OS << "\t.save\t{";
164 
165  InstPrinter.printRegName(OS, RegList[0]);
166 
167  for (unsigned i = 1, e = RegList.size(); i != e; ++i) {
168  OS << ", ";
169  InstPrinter.printRegName(OS, RegList[i]);
170  }
171 
172  OS << "}\n";
173 }
174 
175 void ARMTargetAsmStreamer::switchVendor(StringRef Vendor) {}
176 
177 void ARMTargetAsmStreamer::emitAttribute(unsigned Attribute, unsigned Value) {
178  OS << "\t.eabi_attribute\t" << Attribute << ", " << Twine(Value);
179  if (IsVerboseAsm) {
181  if (!Name.empty())
182  OS << "\t@ " << Name;
183  }
184  OS << "\n";
185 }
186 
187 void ARMTargetAsmStreamer::emitTextAttribute(unsigned Attribute,
188  StringRef String) {
189  switch (Attribute) {
191  OS << "\t.cpu\t" << String.lower();
192  break;
193  default:
194  OS << "\t.eabi_attribute\t" << Attribute << ", \"" << String << "\"";
195  if (IsVerboseAsm) {
197  if (!Name.empty())
198  OS << "\t@ " << Name;
199  }
200  break;
201  }
202  OS << "\n";
203 }
204 
205 void ARMTargetAsmStreamer::emitIntTextAttribute(unsigned Attribute,
206  unsigned IntValue,
207  StringRef StringValue) {
208  switch (Attribute) {
209  default: llvm_unreachable("unsupported multi-value attribute in asm mode");
211  OS << "\t.eabi_attribute\t" << Attribute << ", " << IntValue;
212  if (!StringValue.empty())
213  OS << ", \"" << StringValue << "\"";
214  if (IsVerboseAsm)
215  OS << "\t@ " << ARMBuildAttrs::AttrTypeAsString(Attribute);
216  break;
217  }
218  OS << "\n";
219 }
220 
221 void ARMTargetAsmStreamer::emitArch(ARM::ArchKind Arch) {
222  OS << "\t.arch\t" << ARM::getArchName(Arch) << "\n";
223 }
224 
225 void ARMTargetAsmStreamer::emitArchExtension(unsigned ArchExt) {
226  OS << "\t.arch_extension\t" << ARM::getArchExtName(ArchExt) << "\n";
227 }
228 
229 void ARMTargetAsmStreamer::emitObjectArch(ARM::ArchKind Arch) {
230  OS << "\t.object_arch\t" << ARM::getArchName(Arch) << '\n';
231 }
232 
233 void ARMTargetAsmStreamer::emitFPU(unsigned FPU) {
234  OS << "\t.fpu\t" << ARM::getFPUName(FPU) << "\n";
235 }
236 
237 void ARMTargetAsmStreamer::finishAttributeSection() {}
238 
239 void
240 ARMTargetAsmStreamer::AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *S) {
241  OS << "\t.tlsdescseq\t" << S->getSymbol().getName();
242 }
243 
244 void ARMTargetAsmStreamer::emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) {
245  const MCAsmInfo *MAI = Streamer.getContext().getAsmInfo();
246 
247  OS << "\t.thumb_set\t";
248  Symbol->print(OS, MAI);
249  OS << ", ";
250  Value->print(OS, MAI);
251  OS << '\n';
252 }
253 
254 void ARMTargetAsmStreamer::emitInst(uint32_t Inst, char Suffix) {
255  OS << "\t.inst";
256  if (Suffix)
257  OS << "." << Suffix;
258  OS << "\t0x" << Twine::utohexstr(Inst) << "\n";
259 }
260 
261 void ARMTargetAsmStreamer::emitUnwindRaw(int64_t Offset,
262  const SmallVectorImpl<uint8_t> &Opcodes) {
263  OS << "\t.unwind_raw " << Offset;
264  for (SmallVectorImpl<uint8_t>::const_iterator OCI = Opcodes.begin(),
265  OCE = Opcodes.end();
266  OCI != OCE; ++OCI)
267  OS << ", 0x" << Twine::utohexstr(*OCI);
268  OS << '\n';
269 }
270 
271 class ARMTargetELFStreamer : public ARMTargetStreamer {
272 private:
273  // This structure holds all attributes, accounting for
274  // their string/numeric value, so we can later emit them
275  // in declaration order, keeping all in the same vector
276  struct AttributeItem {
277  enum {
278  HiddenAttribute = 0,
279  NumericAttribute,
280  TextAttribute,
281  NumericAndTextAttributes
282  } Type;
283  unsigned Tag;
284  unsigned IntValue;
285  std::string StringValue;
286 
287  static bool LessTag(const AttributeItem &LHS, const AttributeItem &RHS) {
288  // The conformance tag must be emitted first when serialised
289  // into an object file. Specifically, the addenda to the ARM ABI
290  // states that (2.3.7.4):
291  //
292  // "To simplify recognition by consumers in the common case of
293  // claiming conformity for the whole file, this tag should be
294  // emitted first in a file-scope sub-subsection of the first
295  // public subsection of the attributes section."
296  //
297  // So it is special-cased in this comparison predicate when the
298  // attributes are sorted in finishAttributeSection().
299  return (RHS.Tag != ARMBuildAttrs::conformance) &&
300  ((LHS.Tag == ARMBuildAttrs::conformance) || (LHS.Tag < RHS.Tag));
301  }
302  };
303 
304  StringRef CurrentVendor;
305  unsigned FPU = ARM::FK_INVALID;
309 
310  MCSection *AttributeSection = nullptr;
311 
312  AttributeItem *getAttributeItem(unsigned Attribute) {
313  for (size_t i = 0; i < Contents.size(); ++i)
314  if (Contents[i].Tag == Attribute)
315  return &Contents[i];
316  return nullptr;
317  }
318 
319  void setAttributeItem(unsigned Attribute, unsigned Value,
320  bool OverwriteExisting) {
321  // Look for existing attribute item
322  if (AttributeItem *Item = getAttributeItem(Attribute)) {
323  if (!OverwriteExisting)
324  return;
325  Item->Type = AttributeItem::NumericAttribute;
326  Item->IntValue = Value;
327  return;
328  }
329 
330  // Create new attribute item
331  AttributeItem Item = {
332  AttributeItem::NumericAttribute,
333  Attribute,
334  Value,
335  StringRef("")
336  };
337  Contents.push_back(Item);
338  }
339 
340  void setAttributeItem(unsigned Attribute, StringRef Value,
341  bool OverwriteExisting) {
342  // Look for existing attribute item
343  if (AttributeItem *Item = getAttributeItem(Attribute)) {
344  if (!OverwriteExisting)
345  return;
346  Item->Type = AttributeItem::TextAttribute;
347  Item->StringValue = Value;
348  return;
349  }
350 
351  // Create new attribute item
352  AttributeItem Item = {
353  AttributeItem::TextAttribute,
354  Attribute,
355  0,
356  Value
357  };
358  Contents.push_back(Item);
359  }
360 
361  void setAttributeItems(unsigned Attribute, unsigned IntValue,
362  StringRef StringValue, bool OverwriteExisting) {
363  // Look for existing attribute item
364  if (AttributeItem *Item = getAttributeItem(Attribute)) {
365  if (!OverwriteExisting)
366  return;
367  Item->Type = AttributeItem::NumericAndTextAttributes;
368  Item->IntValue = IntValue;
369  Item->StringValue = StringValue;
370  return;
371  }
372 
373  // Create new attribute item
374  AttributeItem Item = {
375  AttributeItem::NumericAndTextAttributes,
376  Attribute,
377  IntValue,
378  StringValue
379  };
380  Contents.push_back(Item);
381  }
382 
383  void emitArchDefaultAttributes();
384  void emitFPUDefaultAttributes();
385 
386  ARMELFStreamer &getStreamer();
387 
388  void emitFnStart() override;
389  void emitFnEnd() override;
390  void emitCantUnwind() override;
391  void emitPersonality(const MCSymbol *Personality) override;
392  void emitPersonalityIndex(unsigned Index) override;
393  void emitHandlerData() override;
394  void emitSetFP(unsigned FpReg, unsigned SpReg, int64_t Offset = 0) override;
395  void emitMovSP(unsigned Reg, int64_t Offset = 0) override;
396  void emitPad(int64_t Offset) override;
397  void emitRegSave(const SmallVectorImpl<unsigned> &RegList,
398  bool isVector) override;
399  void emitUnwindRaw(int64_t Offset,
400  const SmallVectorImpl<uint8_t> &Opcodes) override;
401 
402  void switchVendor(StringRef Vendor) override;
403  void emitAttribute(unsigned Attribute, unsigned Value) override;
404  void emitTextAttribute(unsigned Attribute, StringRef String) override;
405  void emitIntTextAttribute(unsigned Attribute, unsigned IntValue,
406  StringRef StringValue) override;
407  void emitArch(ARM::ArchKind Arch) override;
408  void emitObjectArch(ARM::ArchKind Arch) override;
409  void emitFPU(unsigned FPU) override;
410  void emitInst(uint32_t Inst, char Suffix = '\0') override;
411  void finishAttributeSection() override;
412  void emitLabel(MCSymbol *Symbol) override;
413 
414  void AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *SRE) override;
415  void emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) override;
416 
417  size_t calculateContentSize() const;
418 
419  // Reset state between object emissions
420  void reset() override;
421 
422 public:
423  ARMTargetELFStreamer(MCStreamer &S)
424  : ARMTargetStreamer(S), CurrentVendor("aeabi") {}
425 };
426 
427 /// Extend the generic ELFStreamer class so that it can emit mapping symbols at
428 /// the appropriate points in the object files. These symbols are defined in the
429 /// ARM ELF ABI: infocenter.arm.com/help/topic/com.arm.../IHI0044D_aaelf.pdf.
430 ///
431 /// In brief: $a, $t or $d should be emitted at the start of each contiguous
432 /// region of ARM code, Thumb code or data in a section. In practice, this
433 /// emission does not rely on explicit assembler directives but on inherent
434 /// properties of the directives doing the emission (e.g. ".byte" is data, "add
435 /// r0, r0, r0" an instruction).
436 ///
437 /// As a result this system is orthogonal to the DataRegion infrastructure used
438 /// by MachO. Beware!
439 class ARMELFStreamer : public MCELFStreamer {
440 public:
441  friend class ARMTargetELFStreamer;
442 
443  ARMELFStreamer(MCContext &Context, std::unique_ptr<MCAsmBackend> TAB,
444  raw_pwrite_stream &OS, std::unique_ptr<MCCodeEmitter> Emitter,
445  bool IsThumb)
446  : MCELFStreamer(Context, std::move(TAB), OS, std::move(Emitter)),
447  IsThumb(IsThumb) {
448  EHReset();
449  }
450 
451  ~ARMELFStreamer() override = default;
452 
453  void FinishImpl() override;
454 
455  // ARM exception handling directives
456  void emitFnStart();
457  void emitFnEnd();
458  void emitCantUnwind();
459  void emitPersonality(const MCSymbol *Per);
460  void emitPersonalityIndex(unsigned index);
461  void emitHandlerData();
462  void emitSetFP(unsigned NewFpReg, unsigned NewSpReg, int64_t Offset = 0);
463  void emitMovSP(unsigned Reg, int64_t Offset = 0);
464  void emitPad(int64_t Offset);
465  void emitRegSave(const SmallVectorImpl<unsigned> &RegList, bool isVector);
466  void emitUnwindRaw(int64_t Offset, const SmallVectorImpl<uint8_t> &Opcodes);
467 
468  void ChangeSection(MCSection *Section, const MCExpr *Subsection) override {
469  LastMappingSymbols[getCurrentSection().first] = std::move(LastEMSInfo);
470  MCELFStreamer::ChangeSection(Section, Subsection);
471  auto LastMappingSymbol = LastMappingSymbols.find(Section);
472  if (LastMappingSymbol != LastMappingSymbols.end()) {
473  LastEMSInfo = std::move(LastMappingSymbol->second);
474  return;
475  }
476  LastEMSInfo.reset(new ElfMappingSymbolInfo(SMLoc(), nullptr, 0));
477  }
478 
479  /// This function is the one used to emit instruction data into the ELF
480  /// streamer. We override it to add the appropriate mapping symbol if
481  /// necessary.
482  void EmitInstruction(const MCInst &Inst, const MCSubtargetInfo &STI,
483  bool) override {
484  if (IsThumb)
485  EmitThumbMappingSymbol();
486  else
487  EmitARMMappingSymbol();
488 
490  }
491 
492  void emitInst(uint32_t Inst, char Suffix) {
493  unsigned Size;
494  char Buffer[4];
495  const bool LittleEndian = getContext().getAsmInfo()->isLittleEndian();
496 
497  switch (Suffix) {
498  case '\0':
499  Size = 4;
500 
501  assert(!IsThumb);
502  EmitARMMappingSymbol();
503  for (unsigned II = 0, IE = Size; II != IE; II++) {
504  const unsigned I = LittleEndian ? (Size - II - 1) : II;
505  Buffer[Size - II - 1] = uint8_t(Inst >> I * CHAR_BIT);
506  }
507 
508  break;
509  case 'n':
510  case 'w':
511  Size = (Suffix == 'n' ? 2 : 4);
512 
513  assert(IsThumb);
514  EmitThumbMappingSymbol();
515  for (unsigned II = 0, IE = Size; II != IE; II = II + 2) {
516  const unsigned I0 = LittleEndian ? II + 0 : (Size - II - 1);
517  const unsigned I1 = LittleEndian ? II + 1 : (Size - II - 2);
518  Buffer[Size - II - 2] = uint8_t(Inst >> I0 * CHAR_BIT);
519  Buffer[Size - II - 1] = uint8_t(Inst >> I1 * CHAR_BIT);
520  }
521 
522  break;
523  default:
524  llvm_unreachable("Invalid Suffix");
525  }
526 
527  MCELFStreamer::EmitBytes(StringRef(Buffer, Size));
528  }
529 
530  /// This is one of the functions used to emit data into an ELF section, so the
531  /// ARM streamer overrides it to add the appropriate mapping symbol ($d) if
532  /// necessary.
533  void EmitBytes(StringRef Data) override {
534  EmitDataMappingSymbol();
536  }
537 
538  void FlushPendingMappingSymbol() {
539  if (!LastEMSInfo->hasInfo())
540  return;
541  ElfMappingSymbolInfo *EMS = LastEMSInfo.get();
542  EmitMappingSymbol("$d", EMS->Loc, EMS->F, EMS->Offset);
543  EMS->resetInfo();
544  }
545 
546  /// This is one of the functions used to emit data into an ELF section, so the
547  /// ARM streamer overrides it to add the appropriate mapping symbol ($d) if
548  /// necessary.
549  void EmitValueImpl(const MCExpr *Value, unsigned Size, SMLoc Loc) override {
550  if (const MCSymbolRefExpr *SRE = dyn_cast_or_null<MCSymbolRefExpr>(Value)) {
551  if (SRE->getKind() == MCSymbolRefExpr::VK_ARM_SBREL && !(Size == 4)) {
552  getContext().reportError(Loc, "relocated expression must be 32-bit");
553  return;
554  }
555  getOrCreateDataFragment();
556  }
557 
558  EmitDataMappingSymbol();
559  MCELFStreamer::EmitValueImpl(Value, Size, Loc);
560  }
561 
562  void EmitAssemblerFlag(MCAssemblerFlag Flag) override {
564 
565  switch (Flag) {
566  case MCAF_SyntaxUnified:
567  return; // no-op here.
568  case MCAF_Code16:
569  IsThumb = true;
570  return; // Change to Thumb mode
571  case MCAF_Code32:
572  IsThumb = false;
573  return; // Change to ARM mode
574  case MCAF_Code64:
575  return;
577  return;
578  }
579  }
580 
581 private:
582  enum ElfMappingSymbol {
583  EMS_None,
584  EMS_ARM,
585  EMS_Thumb,
586  EMS_Data
587  };
588 
589  struct ElfMappingSymbolInfo {
590  explicit ElfMappingSymbolInfo(SMLoc Loc, MCFragment *F, uint64_t O)
591  : Loc(Loc), F(F), Offset(O), State(EMS_None) {}
592  void resetInfo() {
593  F = nullptr;
594  Offset = 0;
595  }
596  bool hasInfo() { return F != nullptr; }
597  SMLoc Loc;
598  MCFragment *F;
599  uint64_t Offset;
600  ElfMappingSymbol State;
601  };
602 
603  void EmitDataMappingSymbol() {
604  if (LastEMSInfo->State == EMS_Data)
605  return;
606  else if (LastEMSInfo->State == EMS_None) {
607  // This is a tentative symbol, it won't really be emitted until it's
608  // actually needed.
609  ElfMappingSymbolInfo *EMS = LastEMSInfo.get();
610  auto *DF = dyn_cast_or_null<MCDataFragment>(getCurrentFragment());
611  if (!DF)
612  return;
613  EMS->Loc = SMLoc();
614  EMS->F = getCurrentFragment();
615  EMS->Offset = DF->getContents().size();
616  LastEMSInfo->State = EMS_Data;
617  return;
618  }
619  EmitMappingSymbol("$d");
620  LastEMSInfo->State = EMS_Data;
621  }
622 
623  void EmitThumbMappingSymbol() {
624  if (LastEMSInfo->State == EMS_Thumb)
625  return;
626  FlushPendingMappingSymbol();
627  EmitMappingSymbol("$t");
628  LastEMSInfo->State = EMS_Thumb;
629  }
630 
631  void EmitARMMappingSymbol() {
632  if (LastEMSInfo->State == EMS_ARM)
633  return;
634  FlushPendingMappingSymbol();
635  EmitMappingSymbol("$a");
636  LastEMSInfo->State = EMS_ARM;
637  }
638 
639  void EmitMappingSymbol(StringRef Name) {
640  auto *Symbol = cast<MCSymbolELF>(getContext().getOrCreateSymbol(
641  Name + "." + Twine(MappingSymbolCounter++)));
642  EmitLabel(Symbol);
643 
644  Symbol->setType(ELF::STT_NOTYPE);
645  Symbol->setBinding(ELF::STB_LOCAL);
646  Symbol->setExternal(false);
647  }
648 
649  void EmitMappingSymbol(StringRef Name, SMLoc Loc, MCFragment *F,
650  uint64_t Offset) {
651  auto *Symbol = cast<MCSymbolELF>(getContext().getOrCreateSymbol(
652  Name + "." + Twine(MappingSymbolCounter++)));
653  EmitLabel(Symbol, Loc, F);
654  Symbol->setType(ELF::STT_NOTYPE);
655  Symbol->setBinding(ELF::STB_LOCAL);
656  Symbol->setExternal(false);
657  Symbol->setOffset(Offset);
658  }
659 
660  void EmitThumbFunc(MCSymbol *Func) override {
661  getAssembler().setIsThumbFunc(Func);
662  EmitSymbolAttribute(Func, MCSA_ELF_TypeFunction);
663  }
664 
665  // Helper functions for ARM exception handling directives
666  void EHReset();
667 
668  // Reset state between object emissions
669  void reset() override;
670 
671  void EmitPersonalityFixup(StringRef Name);
672  void FlushPendingOffset();
673  void FlushUnwindOpcodes(bool NoHandlerData);
674 
675  void SwitchToEHSection(StringRef Prefix, unsigned Type, unsigned Flags,
676  SectionKind Kind, const MCSymbol &Fn);
677  void SwitchToExTabSection(const MCSymbol &FnStart);
678  void SwitchToExIdxSection(const MCSymbol &FnStart);
679 
680  void EmitFixup(const MCExpr *Expr, MCFixupKind Kind);
681 
682  bool IsThumb;
683  int64_t MappingSymbolCounter = 0;
684 
686  LastMappingSymbols;
687 
688  std::unique_ptr<ElfMappingSymbolInfo> LastEMSInfo;
689 
690  // ARM Exception Handling Frame Information
691  MCSymbol *ExTab;
692  MCSymbol *FnStart;
693  const MCSymbol *Personality;
694  unsigned PersonalityIndex;
695  unsigned FPReg; // Frame pointer register
696  int64_t FPOffset; // Offset: (final frame pointer) - (initial $sp)
697  int64_t SPOffset; // Offset: (final $sp) - (initial $sp)
698  int64_t PendingOffset; // Offset: (final $sp) - (emitted $sp)
699  bool UsedFP;
700  bool CantUnwind;
701  SmallVector<uint8_t, 64> Opcodes;
702  UnwindOpcodeAssembler UnwindOpAsm;
703 };
704 
705 } // end anonymous namespace
706 
707 ARMELFStreamer &ARMTargetELFStreamer::getStreamer() {
708  return static_cast<ARMELFStreamer &>(Streamer);
709 }
710 
711 void ARMTargetELFStreamer::emitFnStart() { getStreamer().emitFnStart(); }
712 void ARMTargetELFStreamer::emitFnEnd() { getStreamer().emitFnEnd(); }
713 void ARMTargetELFStreamer::emitCantUnwind() { getStreamer().emitCantUnwind(); }
714 
715 void ARMTargetELFStreamer::emitPersonality(const MCSymbol *Personality) {
716  getStreamer().emitPersonality(Personality);
717 }
718 
719 void ARMTargetELFStreamer::emitPersonalityIndex(unsigned Index) {
720  getStreamer().emitPersonalityIndex(Index);
721 }
722 
723 void ARMTargetELFStreamer::emitHandlerData() {
724  getStreamer().emitHandlerData();
725 }
726 
727 void ARMTargetELFStreamer::emitSetFP(unsigned FpReg, unsigned SpReg,
728  int64_t Offset) {
729  getStreamer().emitSetFP(FpReg, SpReg, Offset);
730 }
731 
732 void ARMTargetELFStreamer::emitMovSP(unsigned Reg, int64_t Offset) {
733  getStreamer().emitMovSP(Reg, Offset);
734 }
735 
736 void ARMTargetELFStreamer::emitPad(int64_t Offset) {
737  getStreamer().emitPad(Offset);
738 }
739 
740 void ARMTargetELFStreamer::emitRegSave(const SmallVectorImpl<unsigned> &RegList,
741  bool isVector) {
742  getStreamer().emitRegSave(RegList, isVector);
743 }
744 
745 void ARMTargetELFStreamer::emitUnwindRaw(int64_t Offset,
746  const SmallVectorImpl<uint8_t> &Opcodes) {
747  getStreamer().emitUnwindRaw(Offset, Opcodes);
748 }
749 
750 void ARMTargetELFStreamer::switchVendor(StringRef Vendor) {
751  assert(!Vendor.empty() && "Vendor cannot be empty.");
752 
753  if (CurrentVendor == Vendor)
754  return;
755 
756  if (!CurrentVendor.empty())
757  finishAttributeSection();
758 
759  assert(Contents.empty() &&
760  ".ARM.attributes should be flushed before changing vendor");
761  CurrentVendor = Vendor;
762 
763 }
764 
765 void ARMTargetELFStreamer::emitAttribute(unsigned Attribute, unsigned Value) {
766  setAttributeItem(Attribute, Value, /* OverwriteExisting= */ true);
767 }
768 
769 void ARMTargetELFStreamer::emitTextAttribute(unsigned Attribute,
770  StringRef Value) {
771  setAttributeItem(Attribute, Value, /* OverwriteExisting= */ true);
772 }
773 
774 void ARMTargetELFStreamer::emitIntTextAttribute(unsigned Attribute,
775  unsigned IntValue,
776  StringRef StringValue) {
777  setAttributeItems(Attribute, IntValue, StringValue,
778  /* OverwriteExisting= */ true);
779 }
780 
781 void ARMTargetELFStreamer::emitArch(ARM::ArchKind Value) {
782  Arch = Value;
783 }
784 
785 void ARMTargetELFStreamer::emitObjectArch(ARM::ArchKind Value) {
786  EmittedArch = Value;
787 }
788 
789 void ARMTargetELFStreamer::emitArchDefaultAttributes() {
790  using namespace ARMBuildAttrs;
791 
792  setAttributeItem(CPU_name,
793  ARM::getCPUAttr(Arch),
794  false);
795 
796  if (EmittedArch == ARM::ArchKind::INVALID)
797  setAttributeItem(CPU_arch,
798  ARM::getArchAttr(Arch),
799  false);
800  else
801  setAttributeItem(CPU_arch,
802  ARM::getArchAttr(EmittedArch),
803  false);
804 
805  switch (Arch) {
806  case ARM::ArchKind::ARMV2:
807  case ARM::ArchKind::ARMV2A:
808  case ARM::ArchKind::ARMV3:
809  case ARM::ArchKind::ARMV3M:
810  case ARM::ArchKind::ARMV4:
811  setAttributeItem(ARM_ISA_use, Allowed, false);
812  break;
813 
814  case ARM::ArchKind::ARMV4T:
815  case ARM::ArchKind::ARMV5T:
816  case ARM::ArchKind::ARMV5TE:
817  case ARM::ArchKind::ARMV6:
818  setAttributeItem(ARM_ISA_use, Allowed, false);
819  setAttributeItem(THUMB_ISA_use, Allowed, false);
820  break;
821 
822  case ARM::ArchKind::ARMV6T2:
823  setAttributeItem(ARM_ISA_use, Allowed, false);
824  setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
825  break;
826 
827  case ARM::ArchKind::ARMV6K:
828  case ARM::ArchKind::ARMV6KZ:
829  setAttributeItem(ARM_ISA_use, Allowed, false);
830  setAttributeItem(THUMB_ISA_use, Allowed, false);
831  setAttributeItem(Virtualization_use, AllowTZ, false);
832  break;
833 
834  case ARM::ArchKind::ARMV6M:
835  setAttributeItem(THUMB_ISA_use, Allowed, false);
836  break;
837 
838  case ARM::ArchKind::ARMV7A:
839  setAttributeItem(CPU_arch_profile, ApplicationProfile, false);
840  setAttributeItem(ARM_ISA_use, Allowed, false);
841  setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
842  break;
843 
844  case ARM::ArchKind::ARMV7R:
845  setAttributeItem(CPU_arch_profile, RealTimeProfile, false);
846  setAttributeItem(ARM_ISA_use, Allowed, false);
847  setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
848  break;
849 
850  case ARM::ArchKind::ARMV7M:
851  setAttributeItem(CPU_arch_profile, MicroControllerProfile, false);
852  setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
853  break;
854 
855  case ARM::ArchKind::ARMV8A:
856  case ARM::ArchKind::ARMV8_1A:
857  case ARM::ArchKind::ARMV8_2A:
858  setAttributeItem(CPU_arch_profile, ApplicationProfile, false);
859  setAttributeItem(ARM_ISA_use, Allowed, false);
860  setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
861  setAttributeItem(MPextension_use, Allowed, false);
862  setAttributeItem(Virtualization_use, AllowTZVirtualization, false);
863  break;
864 
865  case ARM::ArchKind::ARMV8MBaseline:
866  case ARM::ArchKind::ARMV8MMainline:
867  setAttributeItem(THUMB_ISA_use, AllowThumbDerived, false);
868  setAttributeItem(CPU_arch_profile, MicroControllerProfile, false);
869  break;
870 
871  case ARM::ArchKind::IWMMXT:
872  setAttributeItem(ARM_ISA_use, Allowed, false);
873  setAttributeItem(THUMB_ISA_use, Allowed, false);
874  setAttributeItem(WMMX_arch, AllowWMMXv1, false);
875  break;
876 
877  case ARM::ArchKind::IWMMXT2:
878  setAttributeItem(ARM_ISA_use, Allowed, false);
879  setAttributeItem(THUMB_ISA_use, Allowed, false);
880  setAttributeItem(WMMX_arch, AllowWMMXv2, false);
881  break;
882 
883  default:
884  report_fatal_error("Unknown Arch: " + Twine(ARM::getArchName(Arch)));
885  break;
886  }
887 }
888 
889 void ARMTargetELFStreamer::emitFPU(unsigned Value) {
890  FPU = Value;
891 }
892 
893 void ARMTargetELFStreamer::emitFPUDefaultAttributes() {
894  switch (FPU) {
895  case ARM::FK_VFP:
896  case ARM::FK_VFPV2:
897  setAttributeItem(ARMBuildAttrs::FP_arch,
899  /* OverwriteExisting= */ false);
900  break;
901 
902  case ARM::FK_VFPV3:
903  setAttributeItem(ARMBuildAttrs::FP_arch,
905  /* OverwriteExisting= */ false);
906  break;
907 
908  case ARM::FK_VFPV3_FP16:
909  setAttributeItem(ARMBuildAttrs::FP_arch,
911  /* OverwriteExisting= */ false);
912  setAttributeItem(ARMBuildAttrs::FP_HP_extension,
914  /* OverwriteExisting= */ false);
915  break;
916 
917  case ARM::FK_VFPV3_D16:
918  setAttributeItem(ARMBuildAttrs::FP_arch,
920  /* OverwriteExisting= */ false);
921  break;
922 
923  case ARM::FK_VFPV3_D16_FP16:
924  setAttributeItem(ARMBuildAttrs::FP_arch,
926  /* OverwriteExisting= */ false);
927  setAttributeItem(ARMBuildAttrs::FP_HP_extension,
929  /* OverwriteExisting= */ false);
930  break;
931 
932  case ARM::FK_VFPV3XD:
933  setAttributeItem(ARMBuildAttrs::FP_arch,
935  /* OverwriteExisting= */ false);
936  break;
937  case ARM::FK_VFPV3XD_FP16:
938  setAttributeItem(ARMBuildAttrs::FP_arch,
940  /* OverwriteExisting= */ false);
941  setAttributeItem(ARMBuildAttrs::FP_HP_extension,
943  /* OverwriteExisting= */ false);
944  break;
945 
946  case ARM::FK_VFPV4:
947  setAttributeItem(ARMBuildAttrs::FP_arch,
949  /* OverwriteExisting= */ false);
950  break;
951 
952  // ABI_HardFP_use is handled in ARMAsmPrinter, so _SP_D16 is treated the same
953  // as _D16 here.
954  case ARM::FK_FPV4_SP_D16:
955  case ARM::FK_VFPV4_D16:
956  setAttributeItem(ARMBuildAttrs::FP_arch,
958  /* OverwriteExisting= */ false);
959  break;
960 
961  case ARM::FK_FP_ARMV8:
962  setAttributeItem(ARMBuildAttrs::FP_arch,
964  /* OverwriteExisting= */ false);
965  break;
966 
967  // FPV5_D16 is identical to FP_ARMV8 except for the number of D registers, so
968  // uses the FP_ARMV8_D16 build attribute.
969  case ARM::FK_FPV5_SP_D16:
970  case ARM::FK_FPV5_D16:
971  setAttributeItem(ARMBuildAttrs::FP_arch,
973  /* OverwriteExisting= */ false);
974  break;
975 
976  case ARM::FK_NEON:
977  setAttributeItem(ARMBuildAttrs::FP_arch,
979  /* OverwriteExisting= */ false);
980  setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
982  /* OverwriteExisting= */ false);
983  break;
984 
985  case ARM::FK_NEON_FP16:
986  setAttributeItem(ARMBuildAttrs::FP_arch,
988  /* OverwriteExisting= */ false);
989  setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
991  /* OverwriteExisting= */ false);
992  setAttributeItem(ARMBuildAttrs::FP_HP_extension,
994  /* OverwriteExisting= */ false);
995  break;
996 
997  case ARM::FK_NEON_VFPV4:
998  setAttributeItem(ARMBuildAttrs::FP_arch,
1000  /* OverwriteExisting= */ false);
1001  setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
1003  /* OverwriteExisting= */ false);
1004  break;
1005 
1006  case ARM::FK_NEON_FP_ARMV8:
1007  case ARM::FK_CRYPTO_NEON_FP_ARMV8:
1008  setAttributeItem(ARMBuildAttrs::FP_arch,
1010  /* OverwriteExisting= */ false);
1011  // 'Advanced_SIMD_arch' must be emitted not here, but within
1012  // ARMAsmPrinter::emitAttributes(), depending on hasV8Ops() and hasV8_1a()
1013  break;
1014 
1015  case ARM::FK_SOFTVFP:
1016  case ARM::FK_NONE:
1017  break;
1018 
1019  default:
1020  report_fatal_error("Unknown FPU: " + Twine(FPU));
1021  break;
1022  }
1023 }
1024 
1025 size_t ARMTargetELFStreamer::calculateContentSize() const {
1026  size_t Result = 0;
1027  for (size_t i = 0; i < Contents.size(); ++i) {
1028  AttributeItem item = Contents[i];
1029  switch (item.Type) {
1030  case AttributeItem::HiddenAttribute:
1031  break;
1032  case AttributeItem::NumericAttribute:
1033  Result += getULEB128Size(item.Tag);
1034  Result += getULEB128Size(item.IntValue);
1035  break;
1036  case AttributeItem::TextAttribute:
1037  Result += getULEB128Size(item.Tag);
1038  Result += item.StringValue.size() + 1; // string + '\0'
1039  break;
1040  case AttributeItem::NumericAndTextAttributes:
1041  Result += getULEB128Size(item.Tag);
1042  Result += getULEB128Size(item.IntValue);
1043  Result += item.StringValue.size() + 1; // string + '\0';
1044  break;
1045  }
1046  }
1047  return Result;
1048 }
1049 
1050 void ARMTargetELFStreamer::finishAttributeSection() {
1051  // <format-version>
1052  // [ <section-length> "vendor-name"
1053  // [ <file-tag> <size> <attribute>*
1054  // | <section-tag> <size> <section-number>* 0 <attribute>*
1055  // | <symbol-tag> <size> <symbol-number>* 0 <attribute>*
1056  // ]+
1057  // ]*
1058 
1059  if (FPU != ARM::FK_INVALID)
1060  emitFPUDefaultAttributes();
1061 
1062  if (Arch != ARM::ArchKind::INVALID)
1063  emitArchDefaultAttributes();
1064 
1065  if (Contents.empty())
1066  return;
1067 
1068  std::sort(Contents.begin(), Contents.end(), AttributeItem::LessTag);
1069 
1070  ARMELFStreamer &Streamer = getStreamer();
1071 
1072  // Switch to .ARM.attributes section
1073  if (AttributeSection) {
1074  Streamer.SwitchSection(AttributeSection);
1075  } else {
1076  AttributeSection = Streamer.getContext().getELFSection(
1077  ".ARM.attributes", ELF::SHT_ARM_ATTRIBUTES, 0);
1078  Streamer.SwitchSection(AttributeSection);
1079 
1080  // Format version
1081  Streamer.EmitIntValue(0x41, 1);
1082  }
1083 
1084  // Vendor size + Vendor name + '\0'
1085  const size_t VendorHeaderSize = 4 + CurrentVendor.size() + 1;
1086 
1087  // Tag + Tag Size
1088  const size_t TagHeaderSize = 1 + 4;
1089 
1090  const size_t ContentsSize = calculateContentSize();
1091 
1092  Streamer.EmitIntValue(VendorHeaderSize + TagHeaderSize + ContentsSize, 4);
1093  Streamer.EmitBytes(CurrentVendor);
1094  Streamer.EmitIntValue(0, 1); // '\0'
1095 
1096  Streamer.EmitIntValue(ARMBuildAttrs::File, 1);
1097  Streamer.EmitIntValue(TagHeaderSize + ContentsSize, 4);
1098 
1099  // Size should have been accounted for already, now
1100  // emit each field as its type (ULEB or String)
1101  for (size_t i = 0; i < Contents.size(); ++i) {
1102  AttributeItem item = Contents[i];
1103  Streamer.EmitULEB128IntValue(item.Tag);
1104  switch (item.Type) {
1105  default: llvm_unreachable("Invalid attribute type");
1106  case AttributeItem::NumericAttribute:
1107  Streamer.EmitULEB128IntValue(item.IntValue);
1108  break;
1109  case AttributeItem::TextAttribute:
1110  Streamer.EmitBytes(item.StringValue);
1111  Streamer.EmitIntValue(0, 1); // '\0'
1112  break;
1113  case AttributeItem::NumericAndTextAttributes:
1114  Streamer.EmitULEB128IntValue(item.IntValue);
1115  Streamer.EmitBytes(item.StringValue);
1116  Streamer.EmitIntValue(0, 1); // '\0'
1117  break;
1118  }
1119  }
1120 
1121  Contents.clear();
1122  FPU = ARM::FK_INVALID;
1123 }
1124 
1125 void ARMTargetELFStreamer::emitLabel(MCSymbol *Symbol) {
1126  ARMELFStreamer &Streamer = getStreamer();
1127  if (!Streamer.IsThumb)
1128  return;
1129 
1130  Streamer.getAssembler().registerSymbol(*Symbol);
1131  unsigned Type = cast<MCSymbolELF>(Symbol)->getType();
1132  if (Type == ELF::STT_FUNC || Type == ELF::STT_GNU_IFUNC)
1133  Streamer.EmitThumbFunc(Symbol);
1134 }
1135 
1136 void
1137 ARMTargetELFStreamer::AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *S) {
1138  getStreamer().EmitFixup(S, FK_Data_4);
1139 }
1140 
1141 void ARMTargetELFStreamer::emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) {
1142  if (const MCSymbolRefExpr *SRE = dyn_cast<MCSymbolRefExpr>(Value)) {
1143  const MCSymbol &Sym = SRE->getSymbol();
1144  if (!Sym.isDefined()) {
1145  getStreamer().EmitAssignment(Symbol, Value);
1146  return;
1147  }
1148  }
1149 
1150  getStreamer().EmitThumbFunc(Symbol);
1151  getStreamer().EmitAssignment(Symbol, Value);
1152 }
1153 
1154 void ARMTargetELFStreamer::emitInst(uint32_t Inst, char Suffix) {
1155  getStreamer().emitInst(Inst, Suffix);
1156 }
1157 
1158 void ARMTargetELFStreamer::reset() { AttributeSection = nullptr; }
1159 
1160 void ARMELFStreamer::FinishImpl() {
1161  MCTargetStreamer &TS = *getTargetStreamer();
1162  ARMTargetStreamer &ATS = static_cast<ARMTargetStreamer &>(TS);
1163  ATS.finishAttributeSection();
1164 
1166 }
1167 
1168 void ARMELFStreamer::reset() {
1169  MCTargetStreamer &TS = *getTargetStreamer();
1170  ARMTargetStreamer &ATS = static_cast<ARMTargetStreamer &>(TS);
1171  ATS.reset();
1172  MappingSymbolCounter = 0;
1174  LastMappingSymbols.clear();
1175  LastEMSInfo.reset();
1176  // MCELFStreamer clear's the assembler's e_flags. However, for
1177  // arm we manually set the ABI version on streamer creation, so
1178  // do the same here
1179  getAssembler().setELFHeaderEFlags(ELF::EF_ARM_EABI_VER5);
1180 }
1181 
1182 inline void ARMELFStreamer::SwitchToEHSection(StringRef Prefix,
1183  unsigned Type,
1184  unsigned Flags,
1185  SectionKind Kind,
1186  const MCSymbol &Fn) {
1187  const MCSectionELF &FnSection =
1188  static_cast<const MCSectionELF &>(Fn.getSection());
1189 
1190  // Create the name for new section
1191  StringRef FnSecName(FnSection.getSectionName());
1192  SmallString<128> EHSecName(Prefix);
1193  if (FnSecName != ".text") {
1194  EHSecName += FnSecName;
1195  }
1196 
1197  // Get .ARM.extab or .ARM.exidx section
1198  const MCSymbolELF *Group = FnSection.getGroup();
1199  if (Group)
1200  Flags |= ELF::SHF_GROUP;
1201  MCSectionELF *EHSection = getContext().getELFSection(
1202  EHSecName, Type, Flags, 0, Group, FnSection.getUniqueID(),
1203  static_cast<const MCSymbolELF *>(&Fn));
1204 
1205  assert(EHSection && "Failed to get the required EH section");
1206 
1207  // Switch to .ARM.extab or .ARM.exidx section
1208  SwitchSection(EHSection);
1209  EmitCodeAlignment(4);
1210 }
1211 
1212 inline void ARMELFStreamer::SwitchToExTabSection(const MCSymbol &FnStart) {
1213  SwitchToEHSection(".ARM.extab", ELF::SHT_PROGBITS, ELF::SHF_ALLOC,
1214  SectionKind::getData(), FnStart);
1215 }
1216 
1217 inline void ARMELFStreamer::SwitchToExIdxSection(const MCSymbol &FnStart) {
1218  SwitchToEHSection(".ARM.exidx", ELF::SHT_ARM_EXIDX,
1220  SectionKind::getData(), FnStart);
1221 }
1222 
1223 void ARMELFStreamer::EmitFixup(const MCExpr *Expr, MCFixupKind Kind) {
1224  MCDataFragment *Frag = getOrCreateDataFragment();
1225  Frag->getFixups().push_back(MCFixup::create(Frag->getContents().size(), Expr,
1226  Kind));
1227 }
1228 
1229 void ARMELFStreamer::EHReset() {
1230  ExTab = nullptr;
1231  FnStart = nullptr;
1232  Personality = nullptr;
1233  PersonalityIndex = ARM::EHABI::NUM_PERSONALITY_INDEX;
1234  FPReg = ARM::SP;
1235  FPOffset = 0;
1236  SPOffset = 0;
1237  PendingOffset = 0;
1238  UsedFP = false;
1239  CantUnwind = false;
1240 
1241  Opcodes.clear();
1242  UnwindOpAsm.Reset();
1243 }
1244 
1245 void ARMELFStreamer::emitFnStart() {
1246  assert(FnStart == nullptr);
1247  FnStart = getContext().createTempSymbol();
1248  EmitLabel(FnStart);
1249 }
1250 
1251 void ARMELFStreamer::emitFnEnd() {
1252  assert(FnStart && ".fnstart must precedes .fnend");
1253 
1254  // Emit unwind opcodes if there is no .handlerdata directive
1255  if (!ExTab && !CantUnwind)
1256  FlushUnwindOpcodes(true);
1257 
1258  // Emit the exception index table entry
1259  SwitchToExIdxSection(*FnStart);
1260 
1261  if (PersonalityIndex < ARM::EHABI::NUM_PERSONALITY_INDEX)
1262  EmitPersonalityFixup(GetAEABIUnwindPersonalityName(PersonalityIndex));
1263 
1264  const MCSymbolRefExpr *FnStartRef =
1265  MCSymbolRefExpr::create(FnStart,
1267  getContext());
1268 
1269  EmitValue(FnStartRef, 4);
1270 
1271  if (CantUnwind) {
1272  EmitIntValue(ARM::EHABI::EXIDX_CANTUNWIND, 4);
1273  } else if (ExTab) {
1274  // Emit a reference to the unwind opcodes in the ".ARM.extab" section.
1275  const MCSymbolRefExpr *ExTabEntryRef =
1278  getContext());
1279  EmitValue(ExTabEntryRef, 4);
1280  } else {
1281  // For the __aeabi_unwind_cpp_pr0, we have to emit the unwind opcodes in
1282  // the second word of exception index table entry. The size of the unwind
1283  // opcodes should always be 4 bytes.
1284  assert(PersonalityIndex == ARM::EHABI::AEABI_UNWIND_CPP_PR0 &&
1285  "Compact model must use __aeabi_unwind_cpp_pr0 as personality");
1286  assert(Opcodes.size() == 4u &&
1287  "Unwind opcode size for __aeabi_unwind_cpp_pr0 must be equal to 4");
1288  uint64_t Intval = Opcodes[0] |
1289  Opcodes[1] << 8 |
1290  Opcodes[2] << 16 |
1291  Opcodes[3] << 24;
1292  EmitIntValue(Intval, Opcodes.size());
1293  }
1294 
1295  // Switch to the section containing FnStart
1296  SwitchSection(&FnStart->getSection());
1297 
1298  // Clean exception handling frame information
1299  EHReset();
1300 }
1301 
1302 void ARMELFStreamer::emitCantUnwind() { CantUnwind = true; }
1303 
1304 // Add the R_ARM_NONE fixup at the same position
1305 void ARMELFStreamer::EmitPersonalityFixup(StringRef Name) {
1306  const MCSymbol *PersonalitySym = getContext().getOrCreateSymbol(Name);
1307 
1308  const MCSymbolRefExpr *PersonalityRef = MCSymbolRefExpr::create(
1309  PersonalitySym, MCSymbolRefExpr::VK_ARM_NONE, getContext());
1310 
1311  visitUsedExpr(*PersonalityRef);
1312  MCDataFragment *DF = getOrCreateDataFragment();
1313  DF->getFixups().push_back(MCFixup::create(DF->getContents().size(),
1314  PersonalityRef,
1315  MCFixup::getKindForSize(4, false)));
1316 }
1317 
1318 void ARMELFStreamer::FlushPendingOffset() {
1319  if (PendingOffset != 0) {
1320  UnwindOpAsm.EmitSPOffset(-PendingOffset);
1321  PendingOffset = 0;
1322  }
1323 }
1324 
1325 void ARMELFStreamer::FlushUnwindOpcodes(bool NoHandlerData) {
1326  // Emit the unwind opcode to restore $sp.
1327  if (UsedFP) {
1328  const MCRegisterInfo *MRI = getContext().getRegisterInfo();
1329  int64_t LastRegSaveSPOffset = SPOffset - PendingOffset;
1330  UnwindOpAsm.EmitSPOffset(LastRegSaveSPOffset - FPOffset);
1331  UnwindOpAsm.EmitSetSP(MRI->getEncodingValue(FPReg));
1332  } else {
1333  FlushPendingOffset();
1334  }
1335 
1336  // Finalize the unwind opcode sequence
1337  UnwindOpAsm.Finalize(PersonalityIndex, Opcodes);
1338 
1339  // For compact model 0, we have to emit the unwind opcodes in the .ARM.exidx
1340  // section. Thus, we don't have to create an entry in the .ARM.extab
1341  // section.
1342  if (NoHandlerData && PersonalityIndex == ARM::EHABI::AEABI_UNWIND_CPP_PR0)
1343  return;
1344 
1345  // Switch to .ARM.extab section.
1346  SwitchToExTabSection(*FnStart);
1347 
1348  // Create .ARM.extab label for offset in .ARM.exidx
1349  assert(!ExTab);
1350  ExTab = getContext().createTempSymbol();
1351  EmitLabel(ExTab);
1352 
1353  // Emit personality
1354  if (Personality) {
1355  const MCSymbolRefExpr *PersonalityRef =
1356  MCSymbolRefExpr::create(Personality,
1358  getContext());
1359 
1360  EmitValue(PersonalityRef, 4);
1361  }
1362 
1363  // Emit unwind opcodes
1364  assert((Opcodes.size() % 4) == 0 &&
1365  "Unwind opcode size for __aeabi_cpp_unwind_pr0 must be multiple of 4");
1366  for (unsigned I = 0; I != Opcodes.size(); I += 4) {
1367  uint64_t Intval = Opcodes[I] |
1368  Opcodes[I + 1] << 8 |
1369  Opcodes[I + 2] << 16 |
1370  Opcodes[I + 3] << 24;
1371  EmitIntValue(Intval, 4);
1372  }
1373 
1374  // According to ARM EHABI section 9.2, if the __aeabi_unwind_cpp_pr1() or
1375  // __aeabi_unwind_cpp_pr2() is used, then the handler data must be emitted
1376  // after the unwind opcodes. The handler data consists of several 32-bit
1377  // words, and should be terminated by zero.
1378  //
1379  // In case that the .handlerdata directive is not specified by the
1380  // programmer, we should emit zero to terminate the handler data.
1381  if (NoHandlerData && !Personality)
1382  EmitIntValue(0, 4);
1383 }
1384 
1385 void ARMELFStreamer::emitHandlerData() { FlushUnwindOpcodes(false); }
1386 
1387 void ARMELFStreamer::emitPersonality(const MCSymbol *Per) {
1388  Personality = Per;
1389  UnwindOpAsm.setPersonality(Per);
1390 }
1391 
1392 void ARMELFStreamer::emitPersonalityIndex(unsigned Index) {
1393  assert(Index < ARM::EHABI::NUM_PERSONALITY_INDEX && "invalid index");
1394  PersonalityIndex = Index;
1395 }
1396 
1397 void ARMELFStreamer::emitSetFP(unsigned NewFPReg, unsigned NewSPReg,
1398  int64_t Offset) {
1399  assert((NewSPReg == ARM::SP || NewSPReg == FPReg) &&
1400  "the operand of .setfp directive should be either $sp or $fp");
1401 
1402  UsedFP = true;
1403  FPReg = NewFPReg;
1404 
1405  if (NewSPReg == ARM::SP)
1406  FPOffset = SPOffset + Offset;
1407  else
1408  FPOffset += Offset;
1409 }
1410 
1411 void ARMELFStreamer::emitMovSP(unsigned Reg, int64_t Offset) {
1412  assert((Reg != ARM::SP && Reg != ARM::PC) &&
1413  "the operand of .movsp cannot be either sp or pc");
1414  assert(FPReg == ARM::SP && "current FP must be SP");
1415 
1416  FlushPendingOffset();
1417 
1418  FPReg = Reg;
1419  FPOffset = SPOffset + Offset;
1420 
1421  const MCRegisterInfo *MRI = getContext().getRegisterInfo();
1422  UnwindOpAsm.EmitSetSP(MRI->getEncodingValue(FPReg));
1423 }
1424 
1425 void ARMELFStreamer::emitPad(int64_t Offset) {
1426  // Track the change of the $sp offset
1427  SPOffset -= Offset;
1428 
1429  // To squash multiple .pad directives, we should delay the unwind opcode
1430  // until the .save, .vsave, .handlerdata, or .fnend directives.
1431  PendingOffset -= Offset;
1432 }
1433 
1434 void ARMELFStreamer::emitRegSave(const SmallVectorImpl<unsigned> &RegList,
1435  bool IsVector) {
1436  // Collect the registers in the register list
1437  unsigned Count = 0;
1438  uint32_t Mask = 0;
1439  const MCRegisterInfo *MRI = getContext().getRegisterInfo();
1440  for (size_t i = 0; i < RegList.size(); ++i) {
1441  unsigned Reg = MRI->getEncodingValue(RegList[i]);
1442  assert(Reg < (IsVector ? 32U : 16U) && "Register out of range");
1443  unsigned Bit = (1u << Reg);
1444  if ((Mask & Bit) == 0) {
1445  Mask |= Bit;
1446  ++Count;
1447  }
1448  }
1449 
1450  // Track the change the $sp offset: For the .save directive, the
1451  // corresponding push instruction will decrease the $sp by (4 * Count).
1452  // For the .vsave directive, the corresponding vpush instruction will
1453  // decrease $sp by (8 * Count).
1454  SPOffset -= Count * (IsVector ? 8 : 4);
1455 
1456  // Emit the opcode
1457  FlushPendingOffset();
1458  if (IsVector)
1459  UnwindOpAsm.EmitVFPRegSave(Mask);
1460  else
1461  UnwindOpAsm.EmitRegSave(Mask);
1462 }
1463 
1464 void ARMELFStreamer::emitUnwindRaw(int64_t Offset,
1465  const SmallVectorImpl<uint8_t> &Opcodes) {
1466  FlushPendingOffset();
1467  SPOffset = SPOffset - Offset;
1468  UnwindOpAsm.EmitRaw(Opcodes);
1469 }
1470 
1471 namespace llvm {
1472 
1475  MCInstPrinter *InstPrint,
1476  bool isVerboseAsm) {
1477  return new ARMTargetAsmStreamer(S, OS, *InstPrint, isVerboseAsm);
1478 }
1479 
1481  return new ARMTargetStreamer(S);
1482 }
1483 
1485  const MCSubtargetInfo &STI) {
1486  const Triple &TT = STI.getTargetTriple();
1487  if (TT.isOSBinFormatELF())
1488  return new ARMTargetELFStreamer(S);
1489  return new ARMTargetStreamer(S);
1490 }
1491 
1493  std::unique_ptr<MCAsmBackend> TAB,
1494  raw_pwrite_stream &OS,
1495  std::unique_ptr<MCCodeEmitter> Emitter,
1496  bool RelaxAll, bool IsThumb) {
1497  ARMELFStreamer *S = new ARMELFStreamer(Context, std::move(TAB), OS,
1498  std::move(Emitter), IsThumb);
1499  // FIXME: This should eventually end up somewhere else where more
1500  // intelligent flag decisions can be made. For now we are just maintaining
1501  // the status quo for ARM and setting EF_ARM_EABI_VER5 as the default.
1502  S->getAssembler().setELFHeaderEFlags(ELF::EF_ARM_EABI_VER5);
1503 
1504  if (RelaxAll)
1505  S->getAssembler().setRelaxAll(true);
1506  return S;
1507 }
1508 
1509 } // end namespace llvm
Instances of this class represent a uniqued identifier for a section in the current translation unit...
Definition: MCSection.h:39
static SectionKind getData()
Definition: SectionKind.h:202
void EmitBytes(StringRef Data) override
Emit the bytes in Data into the output.
LLVMContext & Context
static const MCSymbolRefExpr * create(const MCSymbol *Symbol, MCContext &Ctx)
Definition: MCExpr.h:305
LLVM_ATTRIBUTE_NORETURN void report_fatal_error(Error Err, bool gen_crash_diag=true)
Report a serious error, calling any installed error handler.
Definition: Error.cpp:115
Compute iterated dominance frontiers using a linear time algorithm.
Definition: AllocatorList.h:24
void reset() override
state management
Definition: MCELFStreamer.h:32
MCSymbol - Instances of this class represent a symbol name in the MC file, and MCSymbols are created ...
Definition: MCSymbol.h:42
MCSection & getSection(bool SetUsed=true) const
Get the section associated with a defined, non-absolute symbol.
Definition: MCSymbol.h:268
LLVM_ATTRIBUTE_ALWAYS_INLINE size_type size() const
Definition: SmallVector.h:136
bool isOSBinFormatELF() const
Tests whether the OS uses the ELF binary format.
Definition: Triple.h:588
formatted_raw_ostream - A raw_ostream that wraps another one and keeps track of line and column posit...
Attribute
Attributes.
Definition: Dwarf.h:107
Target specific streamer interface.
Definition: MCStreamer.h:80
virtual void printRegName(raw_ostream &OS, unsigned RegNo) const
Print the assembler register name.
static MCFixupKind getKindForSize(unsigned Size, bool isPCRel)
Return the generic fixup kind for a value with the given size.
Definition: MCFixup.h:102
virtual void finishAttributeSection()
F(f)
StringRef getCPUAttr(ArchKind AK)
StringRef getArchExtName(unsigned ArchExtKind)
StringRef getFPUName(unsigned FPUKind)
virtual void reset()
Reset any state between object emissions, i.e.
const Triple & getTargetTriple() const
getTargetTriple - Return the target triple string.
void setExternal(bool Value) const
Definition: MCSymbol.h:393
Twine - A lightweight data structure for efficiently representing the concatenation of temporary valu...
Definition: Twine.h:81
StringRef getArchName(ArchKind AK)
Base class for the full range of assembler expressions which are needed for parsing.
Definition: MCExpr.h:36
Reg
All possible values of the reg field in the ModR/M byte.
Represent a reference to a symbol from inside an expression.
Definition: MCExpr.h:165
A four-byte fixup.
Definition: MCFixup.h:26
Context object for machine code objects.
Definition: MCContext.h:59
.code16 (X86) / .code 16 (ARM)
Definition: MCDirectives.h:51
cl::opt< bool > RelaxAll("mc-relax-all", cl::desc("When used with filetype=obj, " "relax all fixups in the emitted object file"))
LLVM_NODISCARD LLVM_ATTRIBUTE_ALWAYS_INLINE bool empty() const
empty - Check if the string is empty.
Definition: StringRef.h:133
void EmitValueImpl(const MCExpr *Value, unsigned Size, SMLoc Loc=SMLoc()) override
Emit the expression Value into the output as a native integer of the given Size bytes.
Special entry for the function never unwind.
Definition: ARMEHABI.h:36
SmallVectorImpl< char > & getContents()
Definition: MCFragment.h:183
MCTargetStreamer * createARMTargetAsmStreamer(MCStreamer &S, formatted_raw_ostream &OS, MCInstPrinter *InstPrint, bool isVerboseAsm)
Instances of this class represent a single low-level machine instruction.
Definition: MCInst.h:159
Flag
These should be considered private to the implementation of the MCInstrDesc class.
Definition: MCInstrDesc.h:121
MCRegisterInfo base class - We assume that the target defines a static array of MCRegisterDesc object...
This class is intended to be used as a base class for asm properties and features specific to the tar...
Definition: MCAsmInfo.h:56
StringRef AttrTypeAsString(unsigned Attr, bool HasTagPrefix=true)
unsigned getUniqueID() const
Definition: MCSectionELF.h:87
void ChangeSection(MCSection *Section, const MCExpr *Subsection) override
Update streamer for a new active section.
MCTargetStreamer * createARMObjectTargetStreamer(MCStreamer &S, const MCSubtargetInfo &STI)
Streaming machine code generation interface.
Definition: MCStreamer.h:169
void print(raw_ostream &OS, const MCAsmInfo *MAI, bool InParens=false) const
Definition: MCExpr.cpp:40
unsigned const MachineRegisterInfo * MRI
const MCSymbolELF * getGroup() const
Definition: MCSectionELF.h:78
The instances of the Type class are immutable: once they are created, they are never changed...
Definition: Type.h:46
LLVM_ATTRIBUTE_ALWAYS_INLINE iterator begin()
Definition: SmallVector.h:116
MCFixupKind
Extensible enumeration to represent the type of a fixup.
Definition: MCFixup.h:23
SmallVectorImpl< MCFixup > & getFixups()
Definition: MCFragment.h:208
.subsections_via_symbols (MachO)
Definition: MCDirectives.h:50
SectionKind - This is a simple POD value that classifies the properties of a section.
Definition: SectionKind.h:23
void setOffset(uint64_t Value)
Definition: MCSymbol.h:326
static MCFixup create(uint32_t Offset, const MCExpr *Value, MCFixupKind Kind, SMLoc Loc=SMLoc())
Definition: MCFixup.h:82
static wasm::ValType getType(const TargetRegisterClass *RC)
#define llvm_unreachable(msg)
Marks that the current location is not supposed to be reachable.
Triple - Helper class for working with autoconf configuration names.
Definition: Triple.h:44
unsigned getULEB128Size(uint64_t Value)
Utility function to get the size of the ULEB128-encoded value.
Definition: LEB128.cpp:20
const MCSymbol & getSymbol() const
Definition: MCExpr.h:318
This is a &#39;vector&#39; (really, a variable-sized array), optimized for the case when the array is small...
Definition: SmallVector.h:864
bool isVector(MCInstrInfo const &MCII, MCInst const &MCI)
static Twine utohexstr(const uint64_t &Val)
Definition: Twine.h:385
.syntax (ARM/ELF)
Definition: MCDirectives.h:49
.code32 (X86) / .code 32 (ARM)
Definition: MCDirectives.h:52
.code64 (X86)
Definition: MCDirectives.h:53
LLVM_ATTRIBUTE_ALWAYS_INLINE iterator end()
Definition: SmallVector.h:120
This is an instance of a target assembly language printer that converts an MCInst to valid target ass...
Definition: MCInstPrinter.h:41
uint16_t getEncodingValue(unsigned RegNo) const
Returns the encoding for RegNo.
MCAssemblerFlag
Definition: MCDirectives.h:48
.type _foo, STT_FUNC # aka
Definition: MCDirectives.h:23
#define I(x, y, z)
Definition: MD5.cpp:58
bool isDefined(bool SetUsed=true) const
isDefined - Check if this symbol is defined (i.e., it has an address).
Definition: MCSymbol.h:249
MCSubtargetInfo - Generic base class for all target subtargets.
This represents a section on linux, lots of unix variants and some bare metal systems.
Definition: MCSectionELF.h:28
StringRef getName() const
getName - Get the symbol name.
Definition: MCSymbol.h:203
An abstract base class for streams implementations that also support a pwrite operation.
Definition: raw_ostream.h:337
const unsigned Kind
Fragment for data and encoded instructions.
Definition: MCFragment.h:226
LLVM_NODISCARD std::string lower() const
Definition: StringRef.cpp:123
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
MCTargetStreamer * createARMNullTargetStreamer(MCStreamer &S)
LLVM Value Representation.
Definition: Value.h:73
constexpr char Size[]
Key for Kernel::Arg::Metadata::mSize.
std::underlying_type< E >::type Mask()
Get a bitmask with 1s in all places up to the high-order bit of E&#39;s largest value.
Definition: BitmaskEnum.h:81
void EmitAssemblerFlag(MCAssemblerFlag Flag) override
Note in the output the specified Flag.
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:49
void sort(Policy policy, RandomAccessIterator Start, RandomAccessIterator End, const Comparator &Comp=Comparator())
Definition: Parallel.h:199
static std::string GetAEABIUnwindPersonalityName(unsigned Index)
Represents a location in source code.
Definition: SMLoc.h:24
unsigned getArchAttr(ArchKind AK)
void FinishImpl() override
Streamer specific finalization.
MCELFStreamer * createARMELFStreamer(MCContext &Context, std::unique_ptr< MCAsmBackend > TAB, raw_pwrite_stream &OS, std::unique_ptr< MCCodeEmitter > Emitter, bool RelaxAll, bool IsThumb)
StringRef getSectionName() const
Definition: MCSectionELF.h:73
void EmitInstruction(const MCInst &Inst, const MCSubtargetInfo &STI, bool=false) override
Emit the given Instruction into the current section.
void print(raw_ostream &OS, const MCAsmInfo *MAI) const
print - Print the value to the stream OS.
Definition: MCSymbol.cpp:59