xref: /freebsd/contrib/llvm-project/llvm/lib/Target/ARM/MCTargetDesc/ARMELFStreamer.cpp (revision 271171e0d97b88ba2a7c3bf750c9672b484c1c13) 
1 //===- lib/MC/ARMELFStreamer.cpp - ELF Object Output for ARM --------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file assembles .s files and emits ARM ELF .o object files. Different
10 // from generic ELF streamer in emitting mapping symbols ($a, $t and $d) to
11 // delimit regions of data and code.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #include "ARMRegisterInfo.h"
16 #include "ARMUnwindOpAsm.h"
17 #include "llvm/ADT/DenseMap.h"
18 #include "llvm/ADT/SmallString.h"
19 #include "llvm/ADT/SmallVector.h"
20 #include "llvm/ADT/StringRef.h"
21 #include "llvm/ADT/Triple.h"
22 #include "llvm/ADT/Twine.h"
23 #include "llvm/BinaryFormat/ELF.h"
24 #include "llvm/MC/MCAsmBackend.h"
25 #include "llvm/MC/MCAsmInfo.h"
26 #include "llvm/MC/MCAssembler.h"
27 #include "llvm/MC/MCCodeEmitter.h"
28 #include "llvm/MC/MCContext.h"
29 #include "llvm/MC/MCELFStreamer.h"
30 #include "llvm/MC/MCExpr.h"
31 #include "llvm/MC/MCFixup.h"
32 #include "llvm/MC/MCFragment.h"
33 #include "llvm/MC/MCInst.h"
34 #include "llvm/MC/MCInstPrinter.h"
35 #include "llvm/MC/MCObjectWriter.h"
36 #include "llvm/MC/MCRegisterInfo.h"
37 #include "llvm/MC/MCSection.h"
38 #include "llvm/MC/MCSectionELF.h"
39 #include "llvm/MC/MCStreamer.h"
40 #include "llvm/MC/MCSubtargetInfo.h"
41 #include "llvm/MC/MCSymbol.h"
42 #include "llvm/MC/MCSymbolELF.h"
43 #include "llvm/MC/SectionKind.h"
44 #include "llvm/Support/ARMBuildAttributes.h"
45 #include "llvm/Support/ARMEHABI.h"
46 #include "llvm/Support/Casting.h"
47 #include "llvm/Support/ErrorHandling.h"
48 #include "llvm/Support/FormattedStream.h"
49 #include "llvm/Support/TargetParser.h"
50 #include "llvm/Support/raw_ostream.h"
51 #include <algorithm>
52 #include <cassert>
53 #include <climits>
54 #include <cstddef>
55 #include <cstdint>
56 #include <string>
57 
58 using namespace llvm;
59 
60 static std::string GetAEABIUnwindPersonalityName(unsigned Index) {
61   assert(Index < ARM::EHABI::NUM_PERSONALITY_INDEX &&
62          "Invalid personality index");
63   return (Twine("__aeabi_unwind_cpp_pr") + Twine(Index)).str();
64 }
65 
66 namespace {
67 
68 class ARMELFStreamer;
69 
70 class ARMTargetAsmStreamer : public ARMTargetStreamer {
71   formatted_raw_ostream &OS;
72   MCInstPrinter &InstPrinter;
73   bool IsVerboseAsm;
74 
75   void emitFnStart() override;
76   void emitFnEnd() override;
77   void emitCantUnwind() override;
78   void emitPersonality(const MCSymbol *Personality) override;
79   void emitPersonalityIndex(unsigned Index) override;
80   void emitHandlerData() override;
81   void emitSetFP(unsigned FpReg, unsigned SpReg, int64_t Offset = 0) override;
82   void emitMovSP(unsigned Reg, int64_t Offset = 0) override;
83   void emitPad(int64_t Offset) override;
84   void emitRegSave(const SmallVectorImpl<unsigned> &RegList,
85                    bool isVector) override;
86   void emitUnwindRaw(int64_t Offset,
87                      const SmallVectorImpl<uint8_t> &Opcodes) override;
88 
89   void switchVendor(StringRef Vendor) override;
90   void emitAttribute(unsigned Attribute, unsigned Value) override;
91   void emitTextAttribute(unsigned Attribute, StringRef String) override;
92   void emitIntTextAttribute(unsigned Attribute, unsigned IntValue,
93                             StringRef StringValue) override;
94   void emitArch(ARM::ArchKind Arch) override;
95   void emitArchExtension(uint64_t ArchExt) override;
96   void emitObjectArch(ARM::ArchKind Arch) override;
97   void emitFPU(unsigned FPU) override;
98   void emitInst(uint32_t Inst, char Suffix = '\0') override;
99   void finishAttributeSection() override;
100 
101   void AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *SRE) override;
102   void emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) override;
103 
104 public:
105   ARMTargetAsmStreamer(MCStreamer &S, formatted_raw_ostream &OS,
106                        MCInstPrinter &InstPrinter, bool VerboseAsm);
107 };
108 
109 ARMTargetAsmStreamer::ARMTargetAsmStreamer(MCStreamer &S,
110                                            formatted_raw_ostream &OS,
111                                            MCInstPrinter &InstPrinter,
112                                            bool VerboseAsm)
113     : ARMTargetStreamer(S), OS(OS), InstPrinter(InstPrinter),
114       IsVerboseAsm(VerboseAsm) {}
115 
116 void ARMTargetAsmStreamer::emitFnStart() { OS << "\t.fnstart\n"; }
117 void ARMTargetAsmStreamer::emitFnEnd() { OS << "\t.fnend\n"; }
118 void ARMTargetAsmStreamer::emitCantUnwind() { OS << "\t.cantunwind\n"; }
119 
120 void ARMTargetAsmStreamer::emitPersonality(const MCSymbol *Personality) {
121   OS << "\t.personality " << Personality->getName() << '\n';
122 }
123 
124 void ARMTargetAsmStreamer::emitPersonalityIndex(unsigned Index) {
125   OS << "\t.personalityindex " << Index << '\n';
126 }
127 
128 void ARMTargetAsmStreamer::emitHandlerData() { OS << "\t.handlerdata\n"; }
129 
130 void ARMTargetAsmStreamer::emitSetFP(unsigned FpReg, unsigned SpReg,
131                                      int64_t Offset) {
132   OS << "\t.setfp\t";
133   InstPrinter.printRegName(OS, FpReg);
134   OS << ", ";
135   InstPrinter.printRegName(OS, SpReg);
136   if (Offset)
137     OS << ", #" << Offset;
138   OS << '\n';
139 }
140 
141 void ARMTargetAsmStreamer::emitMovSP(unsigned Reg, int64_t Offset) {
142   assert((Reg != ARM::SP && Reg != ARM::PC) &&
143          "the operand of .movsp cannot be either sp or pc");
144 
145   OS << "\t.movsp\t";
146   InstPrinter.printRegName(OS, Reg);
147   if (Offset)
148     OS << ", #" << Offset;
149   OS << '\n';
150 }
151 
152 void ARMTargetAsmStreamer::emitPad(int64_t Offset) {
153   OS << "\t.pad\t#" << Offset << '\n';
154 }
155 
156 void ARMTargetAsmStreamer::emitRegSave(const SmallVectorImpl<unsigned> &RegList,
157                                        bool isVector) {
158   assert(RegList.size() && "RegList should not be empty");
159   if (isVector)
160     OS << "\t.vsave\t{";
161   else
162     OS << "\t.save\t{";
163 
164   InstPrinter.printRegName(OS, RegList[0]);
165 
166   for (unsigned i = 1, e = RegList.size(); i != e; ++i) {
167     OS << ", ";
168     InstPrinter.printRegName(OS, RegList[i]);
169   }
170 
171   OS << "}\n";
172 }
173 
174 void ARMTargetAsmStreamer::switchVendor(StringRef Vendor) {}
175 
176 void ARMTargetAsmStreamer::emitAttribute(unsigned Attribute, unsigned Value) {
177   OS << "\t.eabi_attribute\t" << Attribute << ", " << Twine(Value);
178   if (IsVerboseAsm) {
179     StringRef Name = ELFAttrs::attrTypeAsString(
180         Attribute, ARMBuildAttrs::getARMAttributeTags());
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) {
190   case ARMBuildAttrs::CPU_name:
191     OS << "\t.cpu\t" << String.lower();
192     break;
193   default:
194     OS << "\t.eabi_attribute\t" << Attribute << ", \"" << String << "\"";
195     if (IsVerboseAsm) {
196       StringRef Name = ELFAttrs::attrTypeAsString(
197           Attribute, ARMBuildAttrs::getARMAttributeTags());
198       if (!Name.empty())
199         OS << "\t@ " << Name;
200     }
201     break;
202   }
203   OS << "\n";
204 }
205 
206 void ARMTargetAsmStreamer::emitIntTextAttribute(unsigned Attribute,
207                                                 unsigned IntValue,
208                                                 StringRef StringValue) {
209   switch (Attribute) {
210   default: llvm_unreachable("unsupported multi-value attribute in asm mode");
211   case ARMBuildAttrs::compatibility:
212     OS << "\t.eabi_attribute\t" << Attribute << ", " << IntValue;
213     if (!StringValue.empty())
214       OS << ", \"" << StringValue << "\"";
215     if (IsVerboseAsm)
216       OS << "\t@ "
217          << ELFAttrs::attrTypeAsString(Attribute,
218                                        ARMBuildAttrs::getARMAttributeTags());
219     break;
220   }
221   OS << "\n";
222 }
223 
224 void ARMTargetAsmStreamer::emitArch(ARM::ArchKind Arch) {
225   OS << "\t.arch\t" << ARM::getArchName(Arch) << "\n";
226 }
227 
228 void ARMTargetAsmStreamer::emitArchExtension(uint64_t ArchExt) {
229   OS << "\t.arch_extension\t" << ARM::getArchExtName(ArchExt) << "\n";
230 }
231 
232 void ARMTargetAsmStreamer::emitObjectArch(ARM::ArchKind Arch) {
233   OS << "\t.object_arch\t" << ARM::getArchName(Arch) << '\n';
234 }
235 
236 void ARMTargetAsmStreamer::emitFPU(unsigned FPU) {
237   OS << "\t.fpu\t" << ARM::getFPUName(FPU) << "\n";
238 }
239 
240 void ARMTargetAsmStreamer::finishAttributeSection() {}
241 
242 void
243 ARMTargetAsmStreamer::AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *S) {
244   OS << "\t.tlsdescseq\t" << S->getSymbol().getName() << "\n";
245 }
246 
247 void ARMTargetAsmStreamer::emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) {
248   const MCAsmInfo *MAI = Streamer.getContext().getAsmInfo();
249 
250   OS << "\t.thumb_set\t";
251   Symbol->print(OS, MAI);
252   OS << ", ";
253   Value->print(OS, MAI);
254   OS << '\n';
255 }
256 
257 void ARMTargetAsmStreamer::emitInst(uint32_t Inst, char Suffix) {
258   OS << "\t.inst";
259   if (Suffix)
260     OS << "." << Suffix;
261   OS << "\t0x" << Twine::utohexstr(Inst) << "\n";
262 }
263 
264 void ARMTargetAsmStreamer::emitUnwindRaw(int64_t Offset,
265                                       const SmallVectorImpl<uint8_t> &Opcodes) {
266   OS << "\t.unwind_raw " << Offset;
267   for (uint8_t Opcode : Opcodes)
268     OS << ", 0x" << Twine::utohexstr(Opcode);
269   OS << '\n';
270 }
271 
272 class ARMTargetELFStreamer : public ARMTargetStreamer {
273 private:
274   StringRef CurrentVendor;
275   unsigned FPU = ARM::FK_INVALID;
276   ARM::ArchKind Arch = ARM::ArchKind::INVALID;
277   ARM::ArchKind EmittedArch = ARM::ArchKind::INVALID;
278 
279   MCSection *AttributeSection = nullptr;
280 
281   void emitArchDefaultAttributes();
282   void emitFPUDefaultAttributes();
283 
284   ARMELFStreamer &getStreamer();
285 
286   void emitFnStart() override;
287   void emitFnEnd() override;
288   void emitCantUnwind() override;
289   void emitPersonality(const MCSymbol *Personality) override;
290   void emitPersonalityIndex(unsigned Index) override;
291   void emitHandlerData() override;
292   void emitSetFP(unsigned FpReg, unsigned SpReg, int64_t Offset = 0) override;
293   void emitMovSP(unsigned Reg, int64_t Offset = 0) override;
294   void emitPad(int64_t Offset) override;
295   void emitRegSave(const SmallVectorImpl<unsigned> &RegList,
296                    bool isVector) override;
297   void emitUnwindRaw(int64_t Offset,
298                      const SmallVectorImpl<uint8_t> &Opcodes) override;
299 
300   void switchVendor(StringRef Vendor) override;
301   void emitAttribute(unsigned Attribute, unsigned Value) override;
302   void emitTextAttribute(unsigned Attribute, StringRef String) override;
303   void emitIntTextAttribute(unsigned Attribute, unsigned IntValue,
304                             StringRef StringValue) override;
305   void emitArch(ARM::ArchKind Arch) override;
306   void emitObjectArch(ARM::ArchKind Arch) override;
307   void emitFPU(unsigned FPU) override;
308   void emitInst(uint32_t Inst, char Suffix = '\0') override;
309   void finishAttributeSection() override;
310   void emitLabel(MCSymbol *Symbol) override;
311 
312   void AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *SRE) override;
313   void emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) override;
314 
315   // Reset state between object emissions
316   void reset() override;
317 
318 public:
319   ARMTargetELFStreamer(MCStreamer &S)
320     : ARMTargetStreamer(S), CurrentVendor("aeabi") {}
321 };
322 
323 /// Extend the generic ELFStreamer class so that it can emit mapping symbols at
324 /// the appropriate points in the object files. These symbols are defined in the
325 /// ARM ELF ABI: infocenter.arm.com/help/topic/com.arm.../IHI0044D_aaelf.pdf.
326 ///
327 /// In brief: $a, $t or $d should be emitted at the start of each contiguous
328 /// region of ARM code, Thumb code or data in a section. In practice, this
329 /// emission does not rely on explicit assembler directives but on inherent
330 /// properties of the directives doing the emission (e.g. ".byte" is data, "add
331 /// r0, r0, r0" an instruction).
332 ///
333 /// As a result this system is orthogonal to the DataRegion infrastructure used
334 /// by MachO. Beware!
335 class ARMELFStreamer : public MCELFStreamer {
336 public:
337   friend class ARMTargetELFStreamer;
338 
339   ARMELFStreamer(MCContext &Context, std::unique_ptr<MCAsmBackend> TAB,
340                  std::unique_ptr<MCObjectWriter> OW,
341                  std::unique_ptr<MCCodeEmitter> Emitter, bool IsThumb,
342                  bool IsAndroid)
343       : MCELFStreamer(Context, std::move(TAB), std::move(OW),
344                       std::move(Emitter)),
345         IsThumb(IsThumb), IsAndroid(IsAndroid) {
346     EHReset();
347   }
348 
349   ~ARMELFStreamer() override = default;
350 
351   void finishImpl() override;
352 
353   // ARM exception handling directives
354   void emitFnStart();
355   void emitFnEnd();
356   void emitCantUnwind();
357   void emitPersonality(const MCSymbol *Per);
358   void emitPersonalityIndex(unsigned index);
359   void emitHandlerData();
360   void emitSetFP(unsigned NewFpReg, unsigned NewSpReg, int64_t Offset = 0);
361   void emitMovSP(unsigned Reg, int64_t Offset = 0);
362   void emitPad(int64_t Offset);
363   void emitRegSave(const SmallVectorImpl<unsigned> &RegList, bool isVector);
364   void emitUnwindRaw(int64_t Offset, const SmallVectorImpl<uint8_t> &Opcodes);
365   void emitFill(const MCExpr &NumBytes, uint64_t FillValue,
366                 SMLoc Loc) override {
367     emitDataMappingSymbol();
368     MCObjectStreamer::emitFill(NumBytes, FillValue, Loc);
369   }
370 
371   void changeSection(MCSection *Section, const MCExpr *Subsection) override {
372     LastMappingSymbols[getCurrentSection().first] = std::move(LastEMSInfo);
373     MCELFStreamer::changeSection(Section, Subsection);
374     auto LastMappingSymbol = LastMappingSymbols.find(Section);
375     if (LastMappingSymbol != LastMappingSymbols.end()) {
376       LastEMSInfo = std::move(LastMappingSymbol->second);
377       return;
378     }
379     LastEMSInfo.reset(new ElfMappingSymbolInfo(SMLoc(), nullptr, 0));
380   }
381 
382   /// This function is the one used to emit instruction data into the ELF
383   /// streamer. We override it to add the appropriate mapping symbol if
384   /// necessary.
385   void emitInstruction(const MCInst &Inst,
386                        const MCSubtargetInfo &STI) override {
387     if (IsThumb)
388       EmitThumbMappingSymbol();
389     else
390       EmitARMMappingSymbol();
391 
392     MCELFStreamer::emitInstruction(Inst, STI);
393   }
394 
395   void emitInst(uint32_t Inst, char Suffix) {
396     unsigned Size;
397     char Buffer[4];
398     const bool LittleEndian = getContext().getAsmInfo()->isLittleEndian();
399 
400     switch (Suffix) {
401     case '\0':
402       Size = 4;
403 
404       assert(!IsThumb);
405       EmitARMMappingSymbol();
406       for (unsigned II = 0, IE = Size; II != IE; II++) {
407         const unsigned I = LittleEndian ? (Size - II - 1) : II;
408         Buffer[Size - II - 1] = uint8_t(Inst >> I * CHAR_BIT);
409       }
410 
411       break;
412     case 'n':
413     case 'w':
414       Size = (Suffix == 'n' ? 2 : 4);
415 
416       assert(IsThumb);
417       EmitThumbMappingSymbol();
418       // Thumb wide instructions are emitted as a pair of 16-bit words of the
419       // appropriate endianness.
420       for (unsigned II = 0, IE = Size; II != IE; II = II + 2) {
421         const unsigned I0 = LittleEndian ? II + 0 : II + 1;
422         const unsigned I1 = LittleEndian ? II + 1 : II + 0;
423         Buffer[Size - II - 2] = uint8_t(Inst >> I0 * CHAR_BIT);
424         Buffer[Size - II - 1] = uint8_t(Inst >> I1 * CHAR_BIT);
425       }
426 
427       break;
428     default:
429       llvm_unreachable("Invalid Suffix");
430     }
431 
432     MCELFStreamer::emitBytes(StringRef(Buffer, Size));
433   }
434 
435   /// This is one of the functions used to emit data into an ELF section, so the
436   /// ARM streamer overrides it to add the appropriate mapping symbol ($d) if
437   /// necessary.
438   void emitBytes(StringRef Data) override {
439     emitDataMappingSymbol();
440     MCELFStreamer::emitBytes(Data);
441   }
442 
443   void FlushPendingMappingSymbol() {
444     if (!LastEMSInfo->hasInfo())
445       return;
446     ElfMappingSymbolInfo *EMS = LastEMSInfo.get();
447     EmitMappingSymbol("$d", EMS->Loc, EMS->F, EMS->Offset);
448     EMS->resetInfo();
449   }
450 
451   /// This is one of the functions used to emit data into an ELF section, so the
452   /// ARM streamer overrides it to add the appropriate mapping symbol ($d) if
453   /// necessary.
454   void emitValueImpl(const MCExpr *Value, unsigned Size, SMLoc Loc) override {
455     if (const MCSymbolRefExpr *SRE = dyn_cast_or_null<MCSymbolRefExpr>(Value)) {
456       if (SRE->getKind() == MCSymbolRefExpr::VK_ARM_SBREL && !(Size == 4)) {
457         getContext().reportError(Loc, "relocated expression must be 32-bit");
458         return;
459       }
460       getOrCreateDataFragment();
461     }
462 
463     emitDataMappingSymbol();
464     MCELFStreamer::emitValueImpl(Value, Size, Loc);
465   }
466 
467   void emitAssemblerFlag(MCAssemblerFlag Flag) override {
468     MCELFStreamer::emitAssemblerFlag(Flag);
469 
470     switch (Flag) {
471     case MCAF_SyntaxUnified:
472       return; // no-op here.
473     case MCAF_Code16:
474       IsThumb = true;
475       return; // Change to Thumb mode
476     case MCAF_Code32:
477       IsThumb = false;
478       return; // Change to ARM mode
479     case MCAF_Code64:
480       return;
481     case MCAF_SubsectionsViaSymbols:
482       return;
483     }
484   }
485 
486   /// If a label is defined before the .type directive sets the label's type
487   /// then the label can't be recorded as thumb function when the label is
488   /// defined. We override emitSymbolAttribute() which is called as part of the
489   /// parsing of .type so that if the symbol has already been defined we can
490   /// record the label as Thumb. FIXME: there is a corner case where the state
491   /// is changed in between the label definition and the .type directive, this
492   /// is not expected to occur in practice and handling it would require the
493   /// backend to track IsThumb for every label.
494   bool emitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute) override {
495     bool Val = MCELFStreamer::emitSymbolAttribute(Symbol, Attribute);
496 
497     if (!IsThumb)
498       return Val;
499 
500     unsigned Type = cast<MCSymbolELF>(Symbol)->getType();
501     if ((Type == ELF::STT_FUNC || Type == ELF::STT_GNU_IFUNC) &&
502         Symbol->isDefined())
503       getAssembler().setIsThumbFunc(Symbol);
504 
505     return Val;
506   };
507 
508 private:
509   enum ElfMappingSymbol {
510     EMS_None,
511     EMS_ARM,
512     EMS_Thumb,
513     EMS_Data
514   };
515 
516   struct ElfMappingSymbolInfo {
517     explicit ElfMappingSymbolInfo(SMLoc Loc, MCFragment *F, uint64_t O)
518         : Loc(Loc), F(F), Offset(O), State(EMS_None) {}
519     void resetInfo() {
520       F = nullptr;
521       Offset = 0;
522     }
523     bool hasInfo() { return F != nullptr; }
524     SMLoc Loc;
525     MCFragment *F;
526     uint64_t Offset;
527     ElfMappingSymbol State;
528   };
529 
530   void emitDataMappingSymbol() {
531     if (LastEMSInfo->State == EMS_Data)
532       return;
533     else if (LastEMSInfo->State == EMS_None) {
534       // This is a tentative symbol, it won't really be emitted until it's
535       // actually needed.
536       ElfMappingSymbolInfo *EMS = LastEMSInfo.get();
537       auto *DF = dyn_cast_or_null<MCDataFragment>(getCurrentFragment());
538       if (!DF)
539         return;
540       EMS->Loc = SMLoc();
541       EMS->F = getCurrentFragment();
542       EMS->Offset = DF->getContents().size();
543       LastEMSInfo->State = EMS_Data;
544       return;
545     }
546     EmitMappingSymbol("$d");
547     LastEMSInfo->State = EMS_Data;
548   }
549 
550   void EmitThumbMappingSymbol() {
551     if (LastEMSInfo->State == EMS_Thumb)
552       return;
553     FlushPendingMappingSymbol();
554     EmitMappingSymbol("$t");
555     LastEMSInfo->State = EMS_Thumb;
556   }
557 
558   void EmitARMMappingSymbol() {
559     if (LastEMSInfo->State == EMS_ARM)
560       return;
561     FlushPendingMappingSymbol();
562     EmitMappingSymbol("$a");
563     LastEMSInfo->State = EMS_ARM;
564   }
565 
566   void EmitMappingSymbol(StringRef Name) {
567     auto *Symbol = cast<MCSymbolELF>(getContext().getOrCreateSymbol(
568         Name + "." + Twine(MappingSymbolCounter++)));
569     emitLabel(Symbol);
570 
571     Symbol->setType(ELF::STT_NOTYPE);
572     Symbol->setBinding(ELF::STB_LOCAL);
573   }
574 
575   void EmitMappingSymbol(StringRef Name, SMLoc Loc, MCFragment *F,
576                          uint64_t Offset) {
577     auto *Symbol = cast<MCSymbolELF>(getContext().getOrCreateSymbol(
578         Name + "." + Twine(MappingSymbolCounter++)));
579     emitLabelAtPos(Symbol, Loc, F, Offset);
580     Symbol->setType(ELF::STT_NOTYPE);
581     Symbol->setBinding(ELF::STB_LOCAL);
582   }
583 
584   void emitThumbFunc(MCSymbol *Func) override {
585     getAssembler().setIsThumbFunc(Func);
586     emitSymbolAttribute(Func, MCSA_ELF_TypeFunction);
587   }
588 
589   // Helper functions for ARM exception handling directives
590   void EHReset();
591 
592   // Reset state between object emissions
593   void reset() override;
594 
595   void EmitPersonalityFixup(StringRef Name);
596   void FlushPendingOffset();
597   void FlushUnwindOpcodes(bool NoHandlerData);
598 
599   void SwitchToEHSection(StringRef Prefix, unsigned Type, unsigned Flags,
600                          SectionKind Kind, const MCSymbol &Fn);
601   void SwitchToExTabSection(const MCSymbol &FnStart);
602   void SwitchToExIdxSection(const MCSymbol &FnStart);
603 
604   void EmitFixup(const MCExpr *Expr, MCFixupKind Kind);
605 
606   bool IsThumb;
607   bool IsAndroid;
608   int64_t MappingSymbolCounter = 0;
609 
610   DenseMap<const MCSection *, std::unique_ptr<ElfMappingSymbolInfo>>
611       LastMappingSymbols;
612 
613   std::unique_ptr<ElfMappingSymbolInfo> LastEMSInfo;
614 
615   // ARM Exception Handling Frame Information
616   MCSymbol *ExTab;
617   MCSymbol *FnStart;
618   const MCSymbol *Personality;
619   unsigned PersonalityIndex;
620   unsigned FPReg; // Frame pointer register
621   int64_t FPOffset; // Offset: (final frame pointer) - (initial $sp)
622   int64_t SPOffset; // Offset: (final $sp) - (initial $sp)
623   int64_t PendingOffset; // Offset: (final $sp) - (emitted $sp)
624   bool UsedFP;
625   bool CantUnwind;
626   SmallVector<uint8_t, 64> Opcodes;
627   UnwindOpcodeAssembler UnwindOpAsm;
628 };
629 
630 } // end anonymous namespace
631 
632 ARMELFStreamer &ARMTargetELFStreamer::getStreamer() {
633   return static_cast<ARMELFStreamer &>(Streamer);
634 }
635 
636 void ARMTargetELFStreamer::emitFnStart() { getStreamer().emitFnStart(); }
637 void ARMTargetELFStreamer::emitFnEnd() { getStreamer().emitFnEnd(); }
638 void ARMTargetELFStreamer::emitCantUnwind() { getStreamer().emitCantUnwind(); }
639 
640 void ARMTargetELFStreamer::emitPersonality(const MCSymbol *Personality) {
641   getStreamer().emitPersonality(Personality);
642 }
643 
644 void ARMTargetELFStreamer::emitPersonalityIndex(unsigned Index) {
645   getStreamer().emitPersonalityIndex(Index);
646 }
647 
648 void ARMTargetELFStreamer::emitHandlerData() {
649   getStreamer().emitHandlerData();
650 }
651 
652 void ARMTargetELFStreamer::emitSetFP(unsigned FpReg, unsigned SpReg,
653                                      int64_t Offset) {
654   getStreamer().emitSetFP(FpReg, SpReg, Offset);
655 }
656 
657 void ARMTargetELFStreamer::emitMovSP(unsigned Reg, int64_t Offset) {
658   getStreamer().emitMovSP(Reg, Offset);
659 }
660 
661 void ARMTargetELFStreamer::emitPad(int64_t Offset) {
662   getStreamer().emitPad(Offset);
663 }
664 
665 void ARMTargetELFStreamer::emitRegSave(const SmallVectorImpl<unsigned> &RegList,
666                                        bool isVector) {
667   getStreamer().emitRegSave(RegList, isVector);
668 }
669 
670 void ARMTargetELFStreamer::emitUnwindRaw(int64_t Offset,
671                                       const SmallVectorImpl<uint8_t> &Opcodes) {
672   getStreamer().emitUnwindRaw(Offset, Opcodes);
673 }
674 
675 void ARMTargetELFStreamer::switchVendor(StringRef Vendor) {
676   assert(!Vendor.empty() && "Vendor cannot be empty.");
677 
678   if (CurrentVendor == Vendor)
679     return;
680 
681   if (!CurrentVendor.empty())
682     finishAttributeSection();
683 
684   assert(getStreamer().Contents.empty() &&
685          ".ARM.attributes should be flushed before changing vendor");
686   CurrentVendor = Vendor;
687 
688 }
689 
690 void ARMTargetELFStreamer::emitAttribute(unsigned Attribute, unsigned Value) {
691   getStreamer().setAttributeItem(Attribute, Value,
692                                  /* OverwriteExisting= */ true);
693 }
694 
695 void ARMTargetELFStreamer::emitTextAttribute(unsigned Attribute,
696                                              StringRef Value) {
697   getStreamer().setAttributeItem(Attribute, Value,
698                                  /* OverwriteExisting= */ true);
699 }
700 
701 void ARMTargetELFStreamer::emitIntTextAttribute(unsigned Attribute,
702                                                 unsigned IntValue,
703                                                 StringRef StringValue) {
704   getStreamer().setAttributeItems(Attribute, IntValue, StringValue,
705                                   /* OverwriteExisting= */ true);
706 }
707 
708 void ARMTargetELFStreamer::emitArch(ARM::ArchKind Value) {
709   Arch = Value;
710 }
711 
712 void ARMTargetELFStreamer::emitObjectArch(ARM::ArchKind Value) {
713   EmittedArch = Value;
714 }
715 
716 void ARMTargetELFStreamer::emitArchDefaultAttributes() {
717   using namespace ARMBuildAttrs;
718   ARMELFStreamer &S = getStreamer();
719 
720   S.setAttributeItem(CPU_name, ARM::getCPUAttr(Arch), false);
721 
722   if (EmittedArch == ARM::ArchKind::INVALID)
723     S.setAttributeItem(CPU_arch, ARM::getArchAttr(Arch), false);
724   else
725     S.setAttributeItem(CPU_arch, ARM::getArchAttr(EmittedArch), false);
726 
727   switch (Arch) {
728   case ARM::ArchKind::ARMV2:
729   case ARM::ArchKind::ARMV2A:
730   case ARM::ArchKind::ARMV3:
731   case ARM::ArchKind::ARMV3M:
732   case ARM::ArchKind::ARMV4:
733     S.setAttributeItem(ARM_ISA_use, Allowed, false);
734     break;
735 
736   case ARM::ArchKind::ARMV4T:
737   case ARM::ArchKind::ARMV5T:
738   case ARM::ArchKind::XSCALE:
739   case ARM::ArchKind::ARMV5TE:
740   case ARM::ArchKind::ARMV6:
741     S.setAttributeItem(ARM_ISA_use, Allowed, false);
742     S.setAttributeItem(THUMB_ISA_use, Allowed, false);
743     break;
744 
745   case ARM::ArchKind::ARMV6T2:
746     S.setAttributeItem(ARM_ISA_use, Allowed, false);
747     S.setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
748     break;
749 
750   case ARM::ArchKind::ARMV6K:
751   case ARM::ArchKind::ARMV6KZ:
752     S.setAttributeItem(ARM_ISA_use, Allowed, false);
753     S.setAttributeItem(THUMB_ISA_use, Allowed, false);
754     S.setAttributeItem(Virtualization_use, AllowTZ, false);
755     break;
756 
757   case ARM::ArchKind::ARMV6M:
758     S.setAttributeItem(THUMB_ISA_use, Allowed, false);
759     break;
760 
761   case ARM::ArchKind::ARMV7A:
762     S.setAttributeItem(CPU_arch_profile, ApplicationProfile, false);
763     S.setAttributeItem(ARM_ISA_use, Allowed, false);
764     S.setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
765     break;
766 
767   case ARM::ArchKind::ARMV7R:
768     S.setAttributeItem(CPU_arch_profile, RealTimeProfile, false);
769     S.setAttributeItem(ARM_ISA_use, Allowed, false);
770     S.setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
771     break;
772 
773   case ARM::ArchKind::ARMV7EM:
774   case ARM::ArchKind::ARMV7M:
775     S.setAttributeItem(CPU_arch_profile, MicroControllerProfile, false);
776     S.setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
777     break;
778 
779   case ARM::ArchKind::ARMV8A:
780   case ARM::ArchKind::ARMV8_1A:
781   case ARM::ArchKind::ARMV8_2A:
782   case ARM::ArchKind::ARMV8_3A:
783   case ARM::ArchKind::ARMV8_4A:
784   case ARM::ArchKind::ARMV8_5A:
785   case ARM::ArchKind::ARMV8_6A:
786   case ARM::ArchKind::ARMV9A:
787   case ARM::ArchKind::ARMV9_1A:
788   case ARM::ArchKind::ARMV9_2A:
789   case ARM::ArchKind::ARMV9_3A:
790     S.setAttributeItem(CPU_arch_profile, ApplicationProfile, false);
791     S.setAttributeItem(ARM_ISA_use, Allowed, false);
792     S.setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
793     S.setAttributeItem(MPextension_use, Allowed, false);
794     S.setAttributeItem(Virtualization_use, AllowTZVirtualization, false);
795     break;
796 
797   case ARM::ArchKind::ARMV8MBaseline:
798   case ARM::ArchKind::ARMV8MMainline:
799     S.setAttributeItem(THUMB_ISA_use, AllowThumbDerived, false);
800     S.setAttributeItem(CPU_arch_profile, MicroControllerProfile, false);
801     break;
802 
803   case ARM::ArchKind::IWMMXT:
804     S.setAttributeItem(ARM_ISA_use, Allowed, false);
805     S.setAttributeItem(THUMB_ISA_use, Allowed, false);
806     S.setAttributeItem(WMMX_arch, AllowWMMXv1, false);
807     break;
808 
809   case ARM::ArchKind::IWMMXT2:
810     S.setAttributeItem(ARM_ISA_use, Allowed, false);
811     S.setAttributeItem(THUMB_ISA_use, Allowed, false);
812     S.setAttributeItem(WMMX_arch, AllowWMMXv2, false);
813     break;
814 
815   default:
816     report_fatal_error("Unknown Arch: " + Twine(ARM::getArchName(Arch)));
817     break;
818   }
819 }
820 
821 void ARMTargetELFStreamer::emitFPU(unsigned Value) {
822   FPU = Value;
823 }
824 
825 void ARMTargetELFStreamer::emitFPUDefaultAttributes() {
826   ARMELFStreamer &S = getStreamer();
827 
828   switch (FPU) {
829   case ARM::FK_VFP:
830   case ARM::FK_VFPV2:
831     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPv2,
832                        /* OverwriteExisting= */ false);
833     break;
834 
835   case ARM::FK_VFPV3:
836     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPv3A,
837                        /* OverwriteExisting= */ false);
838     break;
839 
840   case ARM::FK_VFPV3_FP16:
841     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPv3A,
842                        /* OverwriteExisting= */ false);
843     S.setAttributeItem(ARMBuildAttrs::FP_HP_extension, ARMBuildAttrs::AllowHPFP,
844                        /* OverwriteExisting= */ false);
845     break;
846 
847   case ARM::FK_VFPV3_D16:
848     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPv3B,
849                        /* OverwriteExisting= */ false);
850     break;
851 
852   case ARM::FK_VFPV3_D16_FP16:
853     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPv3B,
854                        /* OverwriteExisting= */ false);
855     S.setAttributeItem(ARMBuildAttrs::FP_HP_extension, ARMBuildAttrs::AllowHPFP,
856                        /* OverwriteExisting= */ false);
857     break;
858 
859   case ARM::FK_VFPV3XD:
860     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPv3B,
861                        /* OverwriteExisting= */ false);
862     break;
863   case ARM::FK_VFPV3XD_FP16:
864     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPv3B,
865                        /* OverwriteExisting= */ false);
866     S.setAttributeItem(ARMBuildAttrs::FP_HP_extension, ARMBuildAttrs::AllowHPFP,
867                        /* OverwriteExisting= */ false);
868     break;
869 
870   case ARM::FK_VFPV4:
871     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPv4A,
872                        /* OverwriteExisting= */ false);
873     break;
874 
875   // ABI_HardFP_use is handled in ARMAsmPrinter, so _SP_D16 is treated the same
876   // as _D16 here.
877   case ARM::FK_FPV4_SP_D16:
878   case ARM::FK_VFPV4_D16:
879     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPv4B,
880                        /* OverwriteExisting= */ false);
881     break;
882 
883   case ARM::FK_FP_ARMV8:
884     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPARMv8A,
885                        /* OverwriteExisting= */ false);
886     break;
887 
888   // FPV5_D16 is identical to FP_ARMV8 except for the number of D registers, so
889   // uses the FP_ARMV8_D16 build attribute.
890   case ARM::FK_FPV5_SP_D16:
891   case ARM::FK_FPV5_D16:
892     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPARMv8B,
893                        /* OverwriteExisting= */ false);
894     break;
895 
896   case ARM::FK_NEON:
897     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPv3A,
898                        /* OverwriteExisting= */ false);
899     S.setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
900                        ARMBuildAttrs::AllowNeon,
901                        /* OverwriteExisting= */ false);
902     break;
903 
904   case ARM::FK_NEON_FP16:
905     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPv3A,
906                        /* OverwriteExisting= */ false);
907     S.setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
908                        ARMBuildAttrs::AllowNeon,
909                        /* OverwriteExisting= */ false);
910     S.setAttributeItem(ARMBuildAttrs::FP_HP_extension, ARMBuildAttrs::AllowHPFP,
911                        /* OverwriteExisting= */ false);
912     break;
913 
914   case ARM::FK_NEON_VFPV4:
915     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPv4A,
916                        /* OverwriteExisting= */ false);
917     S.setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
918                        ARMBuildAttrs::AllowNeon2,
919                        /* OverwriteExisting= */ false);
920     break;
921 
922   case ARM::FK_NEON_FP_ARMV8:
923   case ARM::FK_CRYPTO_NEON_FP_ARMV8:
924     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPARMv8A,
925                        /* OverwriteExisting= */ false);
926     // 'Advanced_SIMD_arch' must be emitted not here, but within
927     // ARMAsmPrinter::emitAttributes(), depending on hasV8Ops() and hasV8_1a()
928     break;
929 
930   case ARM::FK_SOFTVFP:
931   case ARM::FK_NONE:
932     break;
933 
934   default:
935     report_fatal_error("Unknown FPU: " + Twine(FPU));
936     break;
937   }
938 }
939 
940 void ARMTargetELFStreamer::finishAttributeSection() {
941   ARMELFStreamer &S = getStreamer();
942 
943   if (FPU != ARM::FK_INVALID)
944     emitFPUDefaultAttributes();
945 
946   if (Arch != ARM::ArchKind::INVALID)
947     emitArchDefaultAttributes();
948 
949   if (S.Contents.empty())
950     return;
951 
952   auto LessTag = [](const MCELFStreamer::AttributeItem &LHS,
953                     const MCELFStreamer::AttributeItem &RHS) -> bool {
954     // The conformance tag must be emitted first when serialised into an
955     // object file. Specifically, the addenda to the ARM ABI states that
956     // (2.3.7.4):
957     //
958     // "To simplify recognition by consumers in the common case of claiming
959     // conformity for the whole file, this tag should be emitted first in a
960     // file-scope sub-subsection of the first public subsection of the
961     // attributes section."
962     //
963     // So it is special-cased in this comparison predicate when the
964     // attributes are sorted in finishAttributeSection().
965     return (RHS.Tag != ARMBuildAttrs::conformance) &&
966            ((LHS.Tag == ARMBuildAttrs::conformance) || (LHS.Tag < RHS.Tag));
967   };
968   llvm::sort(S.Contents, LessTag);
969 
970   S.emitAttributesSection(CurrentVendor, ".ARM.attributes",
971                           ELF::SHT_ARM_ATTRIBUTES, AttributeSection);
972 
973   FPU = ARM::FK_INVALID;
974 }
975 
976 void ARMTargetELFStreamer::emitLabel(MCSymbol *Symbol) {
977   ARMELFStreamer &Streamer = getStreamer();
978   if (!Streamer.IsThumb)
979     return;
980 
981   Streamer.getAssembler().registerSymbol(*Symbol);
982   unsigned Type = cast<MCSymbolELF>(Symbol)->getType();
983   if (Type == ELF::STT_FUNC || Type == ELF::STT_GNU_IFUNC)
984     Streamer.emitThumbFunc(Symbol);
985 }
986 
987 void
988 ARMTargetELFStreamer::AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *S) {
989   getStreamer().EmitFixup(S, FK_Data_4);
990 }
991 
992 void ARMTargetELFStreamer::emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) {
993   if (const MCSymbolRefExpr *SRE = dyn_cast<MCSymbolRefExpr>(Value)) {
994     const MCSymbol &Sym = SRE->getSymbol();
995     if (!Sym.isDefined()) {
996       getStreamer().emitAssignment(Symbol, Value);
997       return;
998     }
999   }
1000 
1001   getStreamer().emitThumbFunc(Symbol);
1002   getStreamer().emitAssignment(Symbol, Value);
1003 }
1004 
1005 void ARMTargetELFStreamer::emitInst(uint32_t Inst, char Suffix) {
1006   getStreamer().emitInst(Inst, Suffix);
1007 }
1008 
1009 void ARMTargetELFStreamer::reset() { AttributeSection = nullptr; }
1010 
1011 void ARMELFStreamer::finishImpl() {
1012   MCTargetStreamer &TS = *getTargetStreamer();
1013   ARMTargetStreamer &ATS = static_cast<ARMTargetStreamer &>(TS);
1014   ATS.finishAttributeSection();
1015 
1016   MCELFStreamer::finishImpl();
1017 }
1018 
1019 void ARMELFStreamer::reset() {
1020   MCTargetStreamer &TS = *getTargetStreamer();
1021   ARMTargetStreamer &ATS = static_cast<ARMTargetStreamer &>(TS);
1022   ATS.reset();
1023   MappingSymbolCounter = 0;
1024   MCELFStreamer::reset();
1025   LastMappingSymbols.clear();
1026   LastEMSInfo.reset();
1027   // MCELFStreamer clear's the assembler's e_flags. However, for
1028   // arm we manually set the ABI version on streamer creation, so
1029   // do the same here
1030   getAssembler().setELFHeaderEFlags(ELF::EF_ARM_EABI_VER5);
1031 }
1032 
1033 inline void ARMELFStreamer::SwitchToEHSection(StringRef Prefix,
1034                                               unsigned Type,
1035                                               unsigned Flags,
1036                                               SectionKind Kind,
1037                                               const MCSymbol &Fn) {
1038   const MCSectionELF &FnSection =
1039     static_cast<const MCSectionELF &>(Fn.getSection());
1040 
1041   // Create the name for new section
1042   StringRef FnSecName(FnSection.getName());
1043   SmallString<128> EHSecName(Prefix);
1044   if (FnSecName != ".text") {
1045     EHSecName += FnSecName;
1046   }
1047 
1048   // Get .ARM.extab or .ARM.exidx section
1049   const MCSymbolELF *Group = FnSection.getGroup();
1050   if (Group)
1051     Flags |= ELF::SHF_GROUP;
1052   MCSectionELF *EHSection = getContext().getELFSection(
1053       EHSecName, Type, Flags, 0, Group, /*IsComdat=*/true,
1054       FnSection.getUniqueID(),
1055       static_cast<const MCSymbolELF *>(FnSection.getBeginSymbol()));
1056 
1057   assert(EHSection && "Failed to get the required EH section");
1058 
1059   // Switch to .ARM.extab or .ARM.exidx section
1060   SwitchSection(EHSection);
1061   emitValueToAlignment(4, 0, 1, 0);
1062 }
1063 
1064 inline void ARMELFStreamer::SwitchToExTabSection(const MCSymbol &FnStart) {
1065   SwitchToEHSection(".ARM.extab", ELF::SHT_PROGBITS, ELF::SHF_ALLOC,
1066                     SectionKind::getData(), FnStart);
1067 }
1068 
1069 inline void ARMELFStreamer::SwitchToExIdxSection(const MCSymbol &FnStart) {
1070   SwitchToEHSection(".ARM.exidx", ELF::SHT_ARM_EXIDX,
1071                     ELF::SHF_ALLOC | ELF::SHF_LINK_ORDER,
1072                     SectionKind::getData(), FnStart);
1073 }
1074 
1075 void ARMELFStreamer::EmitFixup(const MCExpr *Expr, MCFixupKind Kind) {
1076   MCDataFragment *Frag = getOrCreateDataFragment();
1077   Frag->getFixups().push_back(MCFixup::create(Frag->getContents().size(), Expr,
1078                                               Kind));
1079 }
1080 
1081 void ARMELFStreamer::EHReset() {
1082   ExTab = nullptr;
1083   FnStart = nullptr;
1084   Personality = nullptr;
1085   PersonalityIndex = ARM::EHABI::NUM_PERSONALITY_INDEX;
1086   FPReg = ARM::SP;
1087   FPOffset = 0;
1088   SPOffset = 0;
1089   PendingOffset = 0;
1090   UsedFP = false;
1091   CantUnwind = false;
1092 
1093   Opcodes.clear();
1094   UnwindOpAsm.Reset();
1095 }
1096 
1097 void ARMELFStreamer::emitFnStart() {
1098   assert(FnStart == nullptr);
1099   FnStart = getContext().createTempSymbol();
1100   emitLabel(FnStart);
1101 }
1102 
1103 void ARMELFStreamer::emitFnEnd() {
1104   assert(FnStart && ".fnstart must precedes .fnend");
1105 
1106   // Emit unwind opcodes if there is no .handlerdata directive
1107   if (!ExTab && !CantUnwind)
1108     FlushUnwindOpcodes(true);
1109 
1110   // Emit the exception index table entry
1111   SwitchToExIdxSection(*FnStart);
1112 
1113   // The EHABI requires a dependency preserving R_ARM_NONE relocation to the
1114   // personality routine to protect it from an arbitrary platform's static
1115   // linker garbage collection. We disable this for Android where the unwinder
1116   // is either dynamically linked or directly references the personality
1117   // routine.
1118   if (PersonalityIndex < ARM::EHABI::NUM_PERSONALITY_INDEX && !IsAndroid)
1119     EmitPersonalityFixup(GetAEABIUnwindPersonalityName(PersonalityIndex));
1120 
1121   const MCSymbolRefExpr *FnStartRef =
1122     MCSymbolRefExpr::create(FnStart,
1123                             MCSymbolRefExpr::VK_ARM_PREL31,
1124                             getContext());
1125 
1126   emitValue(FnStartRef, 4);
1127 
1128   if (CantUnwind) {
1129     emitInt32(ARM::EHABI::EXIDX_CANTUNWIND);
1130   } else if (ExTab) {
1131     // Emit a reference to the unwind opcodes in the ".ARM.extab" section.
1132     const MCSymbolRefExpr *ExTabEntryRef =
1133       MCSymbolRefExpr::create(ExTab,
1134                               MCSymbolRefExpr::VK_ARM_PREL31,
1135                               getContext());
1136     emitValue(ExTabEntryRef, 4);
1137   } else {
1138     // For the __aeabi_unwind_cpp_pr0, we have to emit the unwind opcodes in
1139     // the second word of exception index table entry.  The size of the unwind
1140     // opcodes should always be 4 bytes.
1141     assert(PersonalityIndex == ARM::EHABI::AEABI_UNWIND_CPP_PR0 &&
1142            "Compact model must use __aeabi_unwind_cpp_pr0 as personality");
1143     assert(Opcodes.size() == 4u &&
1144            "Unwind opcode size for __aeabi_unwind_cpp_pr0 must be equal to 4");
1145     uint64_t Intval = Opcodes[0] |
1146                       Opcodes[1] << 8 |
1147                       Opcodes[2] << 16 |
1148                       Opcodes[3] << 24;
1149     emitIntValue(Intval, Opcodes.size());
1150   }
1151 
1152   // Switch to the section containing FnStart
1153   SwitchSection(&FnStart->getSection());
1154 
1155   // Clean exception handling frame information
1156   EHReset();
1157 }
1158 
1159 void ARMELFStreamer::emitCantUnwind() { CantUnwind = true; }
1160 
1161 // Add the R_ARM_NONE fixup at the same position
1162 void ARMELFStreamer::EmitPersonalityFixup(StringRef Name) {
1163   const MCSymbol *PersonalitySym = getContext().getOrCreateSymbol(Name);
1164 
1165   const MCSymbolRefExpr *PersonalityRef = MCSymbolRefExpr::create(
1166       PersonalitySym, MCSymbolRefExpr::VK_ARM_NONE, getContext());
1167 
1168   visitUsedExpr(*PersonalityRef);
1169   MCDataFragment *DF = getOrCreateDataFragment();
1170   DF->getFixups().push_back(MCFixup::create(DF->getContents().size(),
1171                                             PersonalityRef,
1172                                             MCFixup::getKindForSize(4, false)));
1173 }
1174 
1175 void ARMELFStreamer::FlushPendingOffset() {
1176   if (PendingOffset != 0) {
1177     UnwindOpAsm.EmitSPOffset(-PendingOffset);
1178     PendingOffset = 0;
1179   }
1180 }
1181 
1182 void ARMELFStreamer::FlushUnwindOpcodes(bool NoHandlerData) {
1183   // Emit the unwind opcode to restore $sp.
1184   if (UsedFP) {
1185     const MCRegisterInfo *MRI = getContext().getRegisterInfo();
1186     int64_t LastRegSaveSPOffset = SPOffset - PendingOffset;
1187     UnwindOpAsm.EmitSPOffset(LastRegSaveSPOffset - FPOffset);
1188     UnwindOpAsm.EmitSetSP(MRI->getEncodingValue(FPReg));
1189   } else {
1190     FlushPendingOffset();
1191   }
1192 
1193   // Finalize the unwind opcode sequence
1194   UnwindOpAsm.Finalize(PersonalityIndex, Opcodes);
1195 
1196   // For compact model 0, we have to emit the unwind opcodes in the .ARM.exidx
1197   // section.  Thus, we don't have to create an entry in the .ARM.extab
1198   // section.
1199   if (NoHandlerData && PersonalityIndex == ARM::EHABI::AEABI_UNWIND_CPP_PR0)
1200     return;
1201 
1202   // Switch to .ARM.extab section.
1203   SwitchToExTabSection(*FnStart);
1204 
1205   // Create .ARM.extab label for offset in .ARM.exidx
1206   assert(!ExTab);
1207   ExTab = getContext().createTempSymbol();
1208   emitLabel(ExTab);
1209 
1210   // Emit personality
1211   if (Personality) {
1212     const MCSymbolRefExpr *PersonalityRef =
1213       MCSymbolRefExpr::create(Personality,
1214                               MCSymbolRefExpr::VK_ARM_PREL31,
1215                               getContext());
1216 
1217     emitValue(PersonalityRef, 4);
1218   }
1219 
1220   // Emit unwind opcodes
1221   assert((Opcodes.size() % 4) == 0 &&
1222          "Unwind opcode size for __aeabi_cpp_unwind_pr0 must be multiple of 4");
1223   for (unsigned I = 0; I != Opcodes.size(); I += 4) {
1224     uint64_t Intval = Opcodes[I] |
1225                       Opcodes[I + 1] << 8 |
1226                       Opcodes[I + 2] << 16 |
1227                       Opcodes[I + 3] << 24;
1228     emitInt32(Intval);
1229   }
1230 
1231   // According to ARM EHABI section 9.2, if the __aeabi_unwind_cpp_pr1() or
1232   // __aeabi_unwind_cpp_pr2() is used, then the handler data must be emitted
1233   // after the unwind opcodes.  The handler data consists of several 32-bit
1234   // words, and should be terminated by zero.
1235   //
1236   // In case that the .handlerdata directive is not specified by the
1237   // programmer, we should emit zero to terminate the handler data.
1238   if (NoHandlerData && !Personality)
1239     emitInt32(0);
1240 }
1241 
1242 void ARMELFStreamer::emitHandlerData() { FlushUnwindOpcodes(false); }
1243 
1244 void ARMELFStreamer::emitPersonality(const MCSymbol *Per) {
1245   Personality = Per;
1246   UnwindOpAsm.setPersonality(Per);
1247 }
1248 
1249 void ARMELFStreamer::emitPersonalityIndex(unsigned Index) {
1250   assert(Index < ARM::EHABI::NUM_PERSONALITY_INDEX && "invalid index");
1251   PersonalityIndex = Index;
1252 }
1253 
1254 void ARMELFStreamer::emitSetFP(unsigned NewFPReg, unsigned NewSPReg,
1255                                int64_t Offset) {
1256   assert((NewSPReg == ARM::SP || NewSPReg == FPReg) &&
1257          "the operand of .setfp directive should be either $sp or $fp");
1258 
1259   UsedFP = true;
1260   FPReg = NewFPReg;
1261 
1262   if (NewSPReg == ARM::SP)
1263     FPOffset = SPOffset + Offset;
1264   else
1265     FPOffset += Offset;
1266 }
1267 
1268 void ARMELFStreamer::emitMovSP(unsigned Reg, int64_t Offset) {
1269   assert((Reg != ARM::SP && Reg != ARM::PC) &&
1270          "the operand of .movsp cannot be either sp or pc");
1271   assert(FPReg == ARM::SP && "current FP must be SP");
1272 
1273   FlushPendingOffset();
1274 
1275   FPReg = Reg;
1276   FPOffset = SPOffset + Offset;
1277 
1278   const MCRegisterInfo *MRI = getContext().getRegisterInfo();
1279   UnwindOpAsm.EmitSetSP(MRI->getEncodingValue(FPReg));
1280 }
1281 
1282 void ARMELFStreamer::emitPad(int64_t Offset) {
1283   // Track the change of the $sp offset
1284   SPOffset -= Offset;
1285 
1286   // To squash multiple .pad directives, we should delay the unwind opcode
1287   // until the .save, .vsave, .handlerdata, or .fnend directives.
1288   PendingOffset -= Offset;
1289 }
1290 
1291 static std::pair<unsigned, unsigned>
1292 collectHWRegs(const MCRegisterInfo &MRI, unsigned Idx,
1293               const SmallVectorImpl<unsigned> &RegList, bool IsVector,
1294               uint32_t &Mask_) {
1295   uint32_t Mask = 0;
1296   unsigned Count = 0;
1297   while (Idx > 0) {
1298     unsigned Reg = RegList[Idx - 1];
1299     if (Reg == ARM::RA_AUTH_CODE)
1300       break;
1301     Reg = MRI.getEncodingValue(Reg);
1302     assert(Reg < (IsVector ? 32U : 16U) && "Register out of range");
1303     unsigned Bit = (1u << Reg);
1304     if ((Mask & Bit) == 0) {
1305       Mask |= Bit;
1306       ++Count;
1307     }
1308     --Idx;
1309   }
1310 
1311   Mask_ = Mask;
1312   return {Idx, Count};
1313 }
1314 
1315 void ARMELFStreamer::emitRegSave(const SmallVectorImpl<unsigned> &RegList,
1316                                  bool IsVector) {
1317   uint32_t Mask;
1318   unsigned Idx, Count;
1319   const MCRegisterInfo &MRI = *getContext().getRegisterInfo();
1320 
1321   // Collect the registers in the register list. Issue unwinding instructions in
1322   // three parts: ordinary hardware registers, return address authentication
1323   // code pseudo register, the rest of the registers. The RA PAC is kept in an
1324   // architectural register (usually r12), but we treat it as a special case in
1325   // order to distinguish between that register containing RA PAC or a general
1326   // value.
1327   Idx = RegList.size();
1328   while (Idx > 0) {
1329     std::tie(Idx, Count) = collectHWRegs(MRI, Idx, RegList, IsVector, Mask);
1330     if (Count) {
1331       // Track the change the $sp offset: For the .save directive, the
1332       // corresponding push instruction will decrease the $sp by (4 * Count).
1333       // For the .vsave directive, the corresponding vpush instruction will
1334       // decrease $sp by (8 * Count).
1335       SPOffset -= Count * (IsVector ? 8 : 4);
1336 
1337       // Emit the opcode
1338       FlushPendingOffset();
1339       if (IsVector)
1340         UnwindOpAsm.EmitVFPRegSave(Mask);
1341       else
1342         UnwindOpAsm.EmitRegSave(Mask);
1343     } else if (Idx > 0 && RegList[Idx - 1] == ARM::RA_AUTH_CODE) {
1344       --Idx;
1345       SPOffset -= 4;
1346       FlushPendingOffset();
1347       UnwindOpAsm.EmitRegSave(0);
1348     }
1349   }
1350 }
1351 
1352 void ARMELFStreamer::emitUnwindRaw(int64_t Offset,
1353                                    const SmallVectorImpl<uint8_t> &Opcodes) {
1354   FlushPendingOffset();
1355   SPOffset = SPOffset - Offset;
1356   UnwindOpAsm.EmitRaw(Opcodes);
1357 }
1358 
1359 namespace llvm {
1360 
1361 MCTargetStreamer *createARMTargetAsmStreamer(MCStreamer &S,
1362                                              formatted_raw_ostream &OS,
1363                                              MCInstPrinter *InstPrint,
1364                                              bool isVerboseAsm) {
1365   return new ARMTargetAsmStreamer(S, OS, *InstPrint, isVerboseAsm);
1366 }
1367 
1368 MCTargetStreamer *createARMNullTargetStreamer(MCStreamer &S) {
1369   return new ARMTargetStreamer(S);
1370 }
1371 
1372 MCTargetStreamer *createARMObjectTargetStreamer(MCStreamer &S,
1373                                                 const MCSubtargetInfo &STI) {
1374   const Triple &TT = STI.getTargetTriple();
1375   if (TT.isOSBinFormatELF())
1376     return new ARMTargetELFStreamer(S);
1377   return new ARMTargetStreamer(S);
1378 }
1379 
1380 MCELFStreamer *createARMELFStreamer(MCContext &Context,
1381                                     std::unique_ptr<MCAsmBackend> TAB,
1382                                     std::unique_ptr<MCObjectWriter> OW,
1383                                     std::unique_ptr<MCCodeEmitter> Emitter,
1384                                     bool RelaxAll, bool IsThumb,
1385                                     bool IsAndroid) {
1386   ARMELFStreamer *S =
1387       new ARMELFStreamer(Context, std::move(TAB), std::move(OW),
1388                          std::move(Emitter), IsThumb, IsAndroid);
1389   // FIXME: This should eventually end up somewhere else where more
1390   // intelligent flag decisions can be made. For now we are just maintaining
1391   // the status quo for ARM and setting EF_ARM_EABI_VER5 as the default.
1392   S->getAssembler().setELFHeaderEFlags(ELF::EF_ARM_EABI_VER5);
1393 
1394   if (RelaxAll)
1395     S->getAssembler().setRelaxAll(true);
1396   return S;
1397 }
1398 
1399 } // end namespace llvm
1400