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