1 //===- lib/MC/ARMELFStreamer.cpp - ELF Object Output for ARM --------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file assembles .s files and emits ARM ELF .o object files. Different
11 // from generic ELF streamer in emitting mapping symbols ($a, $t and $d) to
12 // delimit regions of data and code.
13 //
14 //===----------------------------------------------------------------------===//
15 
16 #include "ARMRegisterInfo.h"
17 #include "ARMUnwindOpAsm.h"
18 #include "llvm/ADT/StringExtras.h"
19 #include "llvm/ADT/Twine.h"
20 #include "llvm/MC/MCAsmBackend.h"
21 #include "llvm/MC/MCAsmInfo.h"
22 #include "llvm/MC/MCAssembler.h"
23 #include "llvm/MC/MCCodeEmitter.h"
24 #include "llvm/MC/MCContext.h"
25 #include "llvm/MC/MCELFStreamer.h"
26 #include "llvm/MC/MCExpr.h"
27 #include "llvm/MC/MCInst.h"
28 #include "llvm/MC/MCInstPrinter.h"
29 #include "llvm/MC/MCObjectFileInfo.h"
30 #include "llvm/MC/MCObjectStreamer.h"
31 #include "llvm/MC/MCRegisterInfo.h"
32 #include "llvm/MC/MCSection.h"
33 #include "llvm/MC/MCSectionELF.h"
34 #include "llvm/MC/MCStreamer.h"
35 #include "llvm/MC/MCSymbolELF.h"
36 #include "llvm/MC/MCValue.h"
37 #include "llvm/Support/ARMBuildAttributes.h"
38 #include "llvm/Support/ARMEHABI.h"
39 #include "llvm/Support/TargetParser.h"
40 #include "llvm/Support/Debug.h"
41 #include "llvm/Support/ELF.h"
42 #include "llvm/Support/FormattedStream.h"
43 #include "llvm/Support/LEB128.h"
44 #include "llvm/Support/raw_ostream.h"
45 #include <algorithm>
46 
47 using namespace llvm;
48 
49 static std::string GetAEABIUnwindPersonalityName(unsigned Index) {
50   assert(Index < ARM::EHABI::NUM_PERSONALITY_INDEX &&
51          "Invalid personality index");
52   return (Twine("__aeabi_unwind_cpp_pr") + Twine(Index)).str();
53 }
54 
55 namespace {
56 
57 class ARMELFStreamer;
58 
59 class ARMTargetAsmStreamer : public ARMTargetStreamer {
60   formatted_raw_ostream &OS;
61   MCInstPrinter &InstPrinter;
62   bool IsVerboseAsm;
63 
64   void emitFnStart() override;
65   void emitFnEnd() override;
66   void emitCantUnwind() override;
67   void emitPersonality(const MCSymbol *Personality) override;
68   void emitPersonalityIndex(unsigned Index) override;
69   void emitHandlerData() override;
70   void emitSetFP(unsigned FpReg, unsigned SpReg, int64_t Offset = 0) override;
71   void emitMovSP(unsigned Reg, int64_t Offset = 0) override;
72   void emitPad(int64_t Offset) override;
73   void emitRegSave(const SmallVectorImpl<unsigned> &RegList,
74                    bool isVector) override;
75   void emitUnwindRaw(int64_t Offset,
76                      const SmallVectorImpl<uint8_t> &Opcodes) override;
77 
78   void switchVendor(StringRef Vendor) override;
79   void emitAttribute(unsigned Attribute, unsigned Value) override;
80   void emitTextAttribute(unsigned Attribute, StringRef String) override;
81   void emitIntTextAttribute(unsigned Attribute, unsigned IntValue,
82                             StringRef StrinValue) override;
83   void emitArch(unsigned Arch) override;
84   void emitArchExtension(unsigned ArchExt) override;
85   void emitObjectArch(unsigned Arch) override;
86   void emitFPU(unsigned FPU) override;
87   void emitInst(uint32_t Inst, char Suffix = '\0') override;
88   void finishAttributeSection() override;
89 
90   void AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *SRE) override;
91   void emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) override;
92 
93 public:
94   ARMTargetAsmStreamer(MCStreamer &S, formatted_raw_ostream &OS,
95                        MCInstPrinter &InstPrinter, bool VerboseAsm);
96 };
97 
98 ARMTargetAsmStreamer::ARMTargetAsmStreamer(MCStreamer &S,
99                                            formatted_raw_ostream &OS,
100                                            MCInstPrinter &InstPrinter,
101                                            bool VerboseAsm)
102     : ARMTargetStreamer(S), OS(OS), InstPrinter(InstPrinter),
103       IsVerboseAsm(VerboseAsm) {}
104 void ARMTargetAsmStreamer::emitFnStart() { OS << "\t.fnstart\n"; }
105 void ARMTargetAsmStreamer::emitFnEnd() { OS << "\t.fnend\n"; }
106 void ARMTargetAsmStreamer::emitCantUnwind() { OS << "\t.cantunwind\n"; }
107 void ARMTargetAsmStreamer::emitPersonality(const MCSymbol *Personality) {
108   OS << "\t.personality " << Personality->getName() << '\n';
109 }
110 void ARMTargetAsmStreamer::emitPersonalityIndex(unsigned Index) {
111   OS << "\t.personalityindex " << Index << '\n';
112 }
113 void ARMTargetAsmStreamer::emitHandlerData() { OS << "\t.handlerdata\n"; }
114 void ARMTargetAsmStreamer::emitSetFP(unsigned FpReg, unsigned SpReg,
115                                      int64_t Offset) {
116   OS << "\t.setfp\t";
117   InstPrinter.printRegName(OS, FpReg);
118   OS << ", ";
119   InstPrinter.printRegName(OS, SpReg);
120   if (Offset)
121     OS << ", #" << Offset;
122   OS << '\n';
123 }
124 void ARMTargetAsmStreamer::emitMovSP(unsigned Reg, int64_t Offset) {
125   assert((Reg != ARM::SP && Reg != ARM::PC) &&
126          "the operand of .movsp cannot be either sp or pc");
127 
128   OS << "\t.movsp\t";
129   InstPrinter.printRegName(OS, Reg);
130   if (Offset)
131     OS << ", #" << Offset;
132   OS << '\n';
133 }
134 void ARMTargetAsmStreamer::emitPad(int64_t Offset) {
135   OS << "\t.pad\t#" << Offset << '\n';
136 }
137 void ARMTargetAsmStreamer::emitRegSave(const SmallVectorImpl<unsigned> &RegList,
138                                        bool isVector) {
139   assert(RegList.size() && "RegList should not be empty");
140   if (isVector)
141     OS << "\t.vsave\t{";
142   else
143     OS << "\t.save\t{";
144 
145   InstPrinter.printRegName(OS, RegList[0]);
146 
147   for (unsigned i = 1, e = RegList.size(); i != e; ++i) {
148     OS << ", ";
149     InstPrinter.printRegName(OS, RegList[i]);
150   }
151 
152   OS << "}\n";
153 }
154 void ARMTargetAsmStreamer::switchVendor(StringRef Vendor) {
155 }
156 void ARMTargetAsmStreamer::emitAttribute(unsigned Attribute, unsigned Value) {
157   OS << "\t.eabi_attribute\t" << Attribute << ", " << Twine(Value);
158   if (IsVerboseAsm) {
159     StringRef Name = ARMBuildAttrs::AttrTypeAsString(Attribute);
160     if (!Name.empty())
161       OS << "\t@ " << Name;
162   }
163   OS << "\n";
164 }
165 void ARMTargetAsmStreamer::emitTextAttribute(unsigned Attribute,
166                                              StringRef String) {
167   switch (Attribute) {
168   case ARMBuildAttrs::CPU_name:
169     OS << "\t.cpu\t" << String.lower();
170     break;
171   default:
172     OS << "\t.eabi_attribute\t" << Attribute << ", \"" << String << "\"";
173     if (IsVerboseAsm) {
174       StringRef Name = ARMBuildAttrs::AttrTypeAsString(Attribute);
175       if (!Name.empty())
176         OS << "\t@ " << Name;
177     }
178     break;
179   }
180   OS << "\n";
181 }
182 void ARMTargetAsmStreamer::emitIntTextAttribute(unsigned Attribute,
183                                                 unsigned IntValue,
184                                                 StringRef StringValue) {
185   switch (Attribute) {
186   default: llvm_unreachable("unsupported multi-value attribute in asm mode");
187   case ARMBuildAttrs::compatibility:
188     OS << "\t.eabi_attribute\t" << Attribute << ", " << IntValue;
189     if (!StringValue.empty())
190       OS << ", \"" << StringValue << "\"";
191     if (IsVerboseAsm)
192       OS << "\t@ " << ARMBuildAttrs::AttrTypeAsString(Attribute);
193     break;
194   }
195   OS << "\n";
196 }
197 void ARMTargetAsmStreamer::emitArch(unsigned Arch) {
198   OS << "\t.arch\t" << ARMTargetParser::getArchName(Arch) << "\n";
199 }
200 void ARMTargetAsmStreamer::emitArchExtension(unsigned ArchExt) {
201   OS << "\t.arch_extension\t" << ARMTargetParser::getArchExtName(ArchExt) << "\n";
202 }
203 void ARMTargetAsmStreamer::emitObjectArch(unsigned Arch) {
204   OS << "\t.object_arch\t" << ARMTargetParser::getArchName(Arch) << '\n';
205 }
206 void ARMTargetAsmStreamer::emitFPU(unsigned FPU) {
207   OS << "\t.fpu\t" << ARMTargetParser::getFPUName(FPU) << "\n";
208 }
209 void ARMTargetAsmStreamer::finishAttributeSection() {
210 }
211 void
212 ARMTargetAsmStreamer::AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *S) {
213   OS << "\t.tlsdescseq\t" << S->getSymbol().getName();
214 }
215 
216 void ARMTargetAsmStreamer::emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) {
217   const MCAsmInfo *MAI = Streamer.getContext().getAsmInfo();
218 
219   OS << "\t.thumb_set\t";
220   Symbol->print(OS, MAI);
221   OS << ", ";
222   Value->print(OS, MAI);
223   OS << '\n';
224 }
225 
226 void ARMTargetAsmStreamer::emitInst(uint32_t Inst, char Suffix) {
227   OS << "\t.inst";
228   if (Suffix)
229     OS << "." << Suffix;
230   OS << "\t0x" << Twine::utohexstr(Inst) << "\n";
231 }
232 
233 void ARMTargetAsmStreamer::emitUnwindRaw(int64_t Offset,
234                                       const SmallVectorImpl<uint8_t> &Opcodes) {
235   OS << "\t.unwind_raw " << Offset;
236   for (SmallVectorImpl<uint8_t>::const_iterator OCI = Opcodes.begin(),
237                                                 OCE = Opcodes.end();
238        OCI != OCE; ++OCI)
239     OS << ", 0x" << Twine::utohexstr(*OCI);
240   OS << '\n';
241 }
242 
243 class ARMTargetELFStreamer : public ARMTargetStreamer {
244 private:
245   // This structure holds all attributes, accounting for
246   // their string/numeric value, so we can later emmit them
247   // in declaration order, keeping all in the same vector
248   struct AttributeItem {
249     enum {
250       HiddenAttribute = 0,
251       NumericAttribute,
252       TextAttribute,
253       NumericAndTextAttributes
254     } Type;
255     unsigned Tag;
256     unsigned IntValue;
257     StringRef StringValue;
258 
259     static bool LessTag(const AttributeItem &LHS, const AttributeItem &RHS) {
260       // The conformance tag must be emitted first when serialised
261       // into an object file. Specifically, the addenda to the ARM ABI
262       // states that (2.3.7.4):
263       //
264       // "To simplify recognition by consumers in the common case of
265       // claiming conformity for the whole file, this tag should be
266       // emitted first in a file-scope sub-subsection of the first
267       // public subsection of the attributes section."
268       //
269       // So it is special-cased in this comparison predicate when the
270       // attributes are sorted in finishAttributeSection().
271       return (RHS.Tag != ARMBuildAttrs::conformance) &&
272              ((LHS.Tag == ARMBuildAttrs::conformance) || (LHS.Tag < RHS.Tag));
273     }
274   };
275 
276   StringRef CurrentVendor;
277   unsigned FPU;
278   unsigned Arch;
279   unsigned EmittedArch;
280   SmallVector<AttributeItem, 64> Contents;
281 
282   MCSection *AttributeSection;
283 
284   AttributeItem *getAttributeItem(unsigned Attribute) {
285     for (size_t i = 0; i < Contents.size(); ++i)
286       if (Contents[i].Tag == Attribute)
287         return &Contents[i];
288     return nullptr;
289   }
290 
291   void setAttributeItem(unsigned Attribute, unsigned Value,
292                         bool OverwriteExisting) {
293     // Look for existing attribute item
294     if (AttributeItem *Item = getAttributeItem(Attribute)) {
295       if (!OverwriteExisting)
296         return;
297       Item->Type = AttributeItem::NumericAttribute;
298       Item->IntValue = Value;
299       return;
300     }
301 
302     // Create new attribute item
303     AttributeItem Item = {
304       AttributeItem::NumericAttribute,
305       Attribute,
306       Value,
307       StringRef("")
308     };
309     Contents.push_back(Item);
310   }
311 
312   void setAttributeItem(unsigned Attribute, StringRef Value,
313                         bool OverwriteExisting) {
314     // Look for existing attribute item
315     if (AttributeItem *Item = getAttributeItem(Attribute)) {
316       if (!OverwriteExisting)
317         return;
318       Item->Type = AttributeItem::TextAttribute;
319       Item->StringValue = Value;
320       return;
321     }
322 
323     // Create new attribute item
324     AttributeItem Item = {
325       AttributeItem::TextAttribute,
326       Attribute,
327       0,
328       Value
329     };
330     Contents.push_back(Item);
331   }
332 
333   void setAttributeItems(unsigned Attribute, unsigned IntValue,
334                          StringRef StringValue, bool OverwriteExisting) {
335     // Look for existing attribute item
336     if (AttributeItem *Item = getAttributeItem(Attribute)) {
337       if (!OverwriteExisting)
338         return;
339       Item->Type = AttributeItem::NumericAndTextAttributes;
340       Item->IntValue = IntValue;
341       Item->StringValue = StringValue;
342       return;
343     }
344 
345     // Create new attribute item
346     AttributeItem Item = {
347       AttributeItem::NumericAndTextAttributes,
348       Attribute,
349       IntValue,
350       StringValue
351     };
352     Contents.push_back(Item);
353   }
354 
355   void emitArchDefaultAttributes();
356   void emitFPUDefaultAttributes();
357 
358   ARMELFStreamer &getStreamer();
359 
360   void emitFnStart() override;
361   void emitFnEnd() override;
362   void emitCantUnwind() override;
363   void emitPersonality(const MCSymbol *Personality) override;
364   void emitPersonalityIndex(unsigned Index) override;
365   void emitHandlerData() override;
366   void emitSetFP(unsigned FpReg, unsigned SpReg, int64_t Offset = 0) override;
367   void emitMovSP(unsigned Reg, int64_t Offset = 0) override;
368   void emitPad(int64_t Offset) override;
369   void emitRegSave(const SmallVectorImpl<unsigned> &RegList,
370                    bool isVector) override;
371   void emitUnwindRaw(int64_t Offset,
372                      const SmallVectorImpl<uint8_t> &Opcodes) override;
373 
374   void switchVendor(StringRef Vendor) override;
375   void emitAttribute(unsigned Attribute, unsigned Value) override;
376   void emitTextAttribute(unsigned Attribute, StringRef String) override;
377   void emitIntTextAttribute(unsigned Attribute, unsigned IntValue,
378                             StringRef StringValue) override;
379   void emitArch(unsigned Arch) override;
380   void emitObjectArch(unsigned Arch) override;
381   void emitFPU(unsigned FPU) override;
382   void emitInst(uint32_t Inst, char Suffix = '\0') override;
383   void finishAttributeSection() override;
384   void emitLabel(MCSymbol *Symbol) override;
385 
386   void AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *SRE) override;
387   void emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) override;
388 
389   size_t calculateContentSize() const;
390 
391 public:
392   ARMTargetELFStreamer(MCStreamer &S)
393     : ARMTargetStreamer(S), CurrentVendor("aeabi"), FPU(ARM::FK_INVALID),
394       Arch(ARM::AK_INVALID), EmittedArch(ARM::AK_INVALID),
395       AttributeSection(nullptr) {}
396 };
397 
398 /// Extend the generic ELFStreamer class so that it can emit mapping symbols at
399 /// the appropriate points in the object files. These symbols are defined in the
400 /// ARM ELF ABI: infocenter.arm.com/help/topic/com.arm.../IHI0044D_aaelf.pdf.
401 ///
402 /// In brief: $a, $t or $d should be emitted at the start of each contiguous
403 /// region of ARM code, Thumb code or data in a section. In practice, this
404 /// emission does not rely on explicit assembler directives but on inherent
405 /// properties of the directives doing the emission (e.g. ".byte" is data, "add
406 /// r0, r0, r0" an instruction).
407 ///
408 /// As a result this system is orthogonal to the DataRegion infrastructure used
409 /// by MachO. Beware!
410 class ARMELFStreamer : public MCELFStreamer {
411 public:
412   friend class ARMTargetELFStreamer;
413 
414   ARMELFStreamer(MCContext &Context, MCAsmBackend &TAB, raw_pwrite_stream &OS,
415                  MCCodeEmitter *Emitter, bool IsThumb)
416       : MCELFStreamer(Context, TAB, OS, Emitter), IsThumb(IsThumb),
417         MappingSymbolCounter(0), LastEMS(EMS_None) {
418     Reset();
419   }
420 
421   ~ARMELFStreamer() {}
422 
423   void FinishImpl() override;
424 
425   // ARM exception handling directives
426   void emitFnStart();
427   void emitFnEnd();
428   void emitCantUnwind();
429   void emitPersonality(const MCSymbol *Per);
430   void emitPersonalityIndex(unsigned index);
431   void emitHandlerData();
432   void emitSetFP(unsigned NewFpReg, unsigned NewSpReg, int64_t Offset = 0);
433   void emitMovSP(unsigned Reg, int64_t Offset = 0);
434   void emitPad(int64_t Offset);
435   void emitRegSave(const SmallVectorImpl<unsigned> &RegList, bool isVector);
436   void emitUnwindRaw(int64_t Offset, const SmallVectorImpl<uint8_t> &Opcodes);
437 
438   void ChangeSection(MCSection *Section, const MCExpr *Subsection) override {
439     // We have to keep track of the mapping symbol state of any sections we
440     // use. Each one should start off as EMS_None, which is provided as the
441     // default constructor by DenseMap::lookup.
442     LastMappingSymbols[getPreviousSection().first] = LastEMS;
443     LastEMS = LastMappingSymbols.lookup(Section);
444 
445     MCELFStreamer::ChangeSection(Section, Subsection);
446   }
447 
448   /// This function is the one used to emit instruction data into the ELF
449   /// streamer. We override it to add the appropriate mapping symbol if
450   /// necessary.
451   void EmitInstruction(const MCInst& Inst,
452                        const MCSubtargetInfo &STI) override {
453     if (IsThumb)
454       EmitThumbMappingSymbol();
455     else
456       EmitARMMappingSymbol();
457 
458     MCELFStreamer::EmitInstruction(Inst, STI);
459   }
460 
461   void emitInst(uint32_t Inst, char Suffix) {
462     unsigned Size;
463     char Buffer[4];
464     const bool LittleEndian = getContext().getAsmInfo()->isLittleEndian();
465 
466     switch (Suffix) {
467     case '\0':
468       Size = 4;
469 
470       assert(!IsThumb);
471       EmitARMMappingSymbol();
472       for (unsigned II = 0, IE = Size; II != IE; II++) {
473         const unsigned I = LittleEndian ? (Size - II - 1) : II;
474         Buffer[Size - II - 1] = uint8_t(Inst >> I * CHAR_BIT);
475       }
476 
477       break;
478     case 'n':
479     case 'w':
480       Size = (Suffix == 'n' ? 2 : 4);
481 
482       assert(IsThumb);
483       EmitThumbMappingSymbol();
484       for (unsigned II = 0, IE = Size; II != IE; II = II + 2) {
485         const unsigned I0 = LittleEndian ? II + 0 : (Size - II - 1);
486         const unsigned I1 = LittleEndian ? II + 1 : (Size - II - 2);
487         Buffer[Size - II - 2] = uint8_t(Inst >> I0 * CHAR_BIT);
488         Buffer[Size - II - 1] = uint8_t(Inst >> I1 * CHAR_BIT);
489       }
490 
491       break;
492     default:
493       llvm_unreachable("Invalid Suffix");
494     }
495 
496     MCELFStreamer::EmitBytes(StringRef(Buffer, Size));
497   }
498 
499   /// This is one of the functions used to emit data into an ELF section, so the
500   /// ARM streamer overrides it to add the appropriate mapping symbol ($d) if
501   /// necessary.
502   void EmitBytes(StringRef Data) override {
503     EmitDataMappingSymbol();
504     MCELFStreamer::EmitBytes(Data);
505   }
506 
507   /// This is one of the functions used to emit data into an ELF section, so the
508   /// ARM streamer overrides it to add the appropriate mapping symbol ($d) if
509   /// necessary.
510   void EmitValueImpl(const MCExpr *Value, unsigned Size,
511                      const SMLoc &Loc) override {
512     if (const MCSymbolRefExpr *SRE = dyn_cast_or_null<MCSymbolRefExpr>(Value))
513       if (SRE->getKind() == MCSymbolRefExpr::VK_ARM_SBREL && !(Size == 4))
514         getContext().reportFatalError(Loc, "relocated expression must be 32-bit");
515 
516     EmitDataMappingSymbol();
517     MCELFStreamer::EmitValueImpl(Value, Size);
518   }
519 
520   void EmitAssemblerFlag(MCAssemblerFlag Flag) override {
521     MCELFStreamer::EmitAssemblerFlag(Flag);
522 
523     switch (Flag) {
524     case MCAF_SyntaxUnified:
525       return; // no-op here.
526     case MCAF_Code16:
527       IsThumb = true;
528       return; // Change to Thumb mode
529     case MCAF_Code32:
530       IsThumb = false;
531       return; // Change to ARM mode
532     case MCAF_Code64:
533       return;
534     case MCAF_SubsectionsViaSymbols:
535       return;
536     }
537   }
538 
539 private:
540   enum ElfMappingSymbol {
541     EMS_None,
542     EMS_ARM,
543     EMS_Thumb,
544     EMS_Data
545   };
546 
547   void EmitDataMappingSymbol() {
548     if (LastEMS == EMS_Data) return;
549     EmitMappingSymbol("$d");
550     LastEMS = EMS_Data;
551   }
552 
553   void EmitThumbMappingSymbol() {
554     if (LastEMS == EMS_Thumb) return;
555     EmitMappingSymbol("$t");
556     LastEMS = EMS_Thumb;
557   }
558 
559   void EmitARMMappingSymbol() {
560     if (LastEMS == EMS_ARM) return;
561     EmitMappingSymbol("$a");
562     LastEMS = EMS_ARM;
563   }
564 
565   void EmitMappingSymbol(StringRef Name) {
566     MCSymbol *Start = getContext().createTempSymbol();
567     EmitLabel(Start);
568 
569     auto *Symbol = cast<MCSymbolELF>(getContext().getOrCreateSymbol(
570         Name + "." + Twine(MappingSymbolCounter++)));
571 
572     getAssembler().registerSymbol(*Symbol);
573     Symbol->setType(ELF::STT_NOTYPE);
574     Symbol->setBinding(ELF::STB_LOCAL);
575     Symbol->setExternal(false);
576     AssignSection(Symbol, getCurrentSection().first);
577 
578     const MCExpr *Value = MCSymbolRefExpr::create(Start, getContext());
579     Symbol->setVariableValue(Value);
580   }
581 
582   void EmitThumbFunc(MCSymbol *Func) override {
583     getAssembler().setIsThumbFunc(Func);
584     EmitSymbolAttribute(Func, MCSA_ELF_TypeFunction);
585   }
586 
587   // Helper functions for ARM exception handling directives
588   void Reset();
589 
590   void EmitPersonalityFixup(StringRef Name);
591   void FlushPendingOffset();
592   void FlushUnwindOpcodes(bool NoHandlerData);
593 
594   void SwitchToEHSection(const char *Prefix, unsigned Type, unsigned Flags,
595                          SectionKind Kind, const MCSymbol &Fn);
596   void SwitchToExTabSection(const MCSymbol &FnStart);
597   void SwitchToExIdxSection(const MCSymbol &FnStart);
598 
599   void EmitFixup(const MCExpr *Expr, MCFixupKind Kind);
600 
601   bool IsThumb;
602   int64_t MappingSymbolCounter;
603 
604   DenseMap<const MCSection *, ElfMappingSymbol> LastMappingSymbols;
605   ElfMappingSymbol LastEMS;
606 
607   // ARM Exception Handling Frame Information
608   MCSymbol *ExTab;
609   MCSymbol *FnStart;
610   const MCSymbol *Personality;
611   unsigned PersonalityIndex;
612   unsigned FPReg; // Frame pointer register
613   int64_t FPOffset; // Offset: (final frame pointer) - (initial $sp)
614   int64_t SPOffset; // Offset: (final $sp) - (initial $sp)
615   int64_t PendingOffset; // Offset: (final $sp) - (emitted $sp)
616   bool UsedFP;
617   bool CantUnwind;
618   SmallVector<uint8_t, 64> Opcodes;
619   UnwindOpcodeAssembler UnwindOpAsm;
620 };
621 } // end anonymous namespace
622 
623 ARMELFStreamer &ARMTargetELFStreamer::getStreamer() {
624   return static_cast<ARMELFStreamer &>(Streamer);
625 }
626 
627 void ARMTargetELFStreamer::emitFnStart() { getStreamer().emitFnStart(); }
628 void ARMTargetELFStreamer::emitFnEnd() { getStreamer().emitFnEnd(); }
629 void ARMTargetELFStreamer::emitCantUnwind() { getStreamer().emitCantUnwind(); }
630 void ARMTargetELFStreamer::emitPersonality(const MCSymbol *Personality) {
631   getStreamer().emitPersonality(Personality);
632 }
633 void ARMTargetELFStreamer::emitPersonalityIndex(unsigned Index) {
634   getStreamer().emitPersonalityIndex(Index);
635 }
636 void ARMTargetELFStreamer::emitHandlerData() {
637   getStreamer().emitHandlerData();
638 }
639 void ARMTargetELFStreamer::emitSetFP(unsigned FpReg, unsigned SpReg,
640                                      int64_t Offset) {
641   getStreamer().emitSetFP(FpReg, SpReg, Offset);
642 }
643 void ARMTargetELFStreamer::emitMovSP(unsigned Reg, int64_t Offset) {
644   getStreamer().emitMovSP(Reg, Offset);
645 }
646 void ARMTargetELFStreamer::emitPad(int64_t Offset) {
647   getStreamer().emitPad(Offset);
648 }
649 void ARMTargetELFStreamer::emitRegSave(const SmallVectorImpl<unsigned> &RegList,
650                                        bool isVector) {
651   getStreamer().emitRegSave(RegList, isVector);
652 }
653 void ARMTargetELFStreamer::emitUnwindRaw(int64_t Offset,
654                                       const SmallVectorImpl<uint8_t> &Opcodes) {
655   getStreamer().emitUnwindRaw(Offset, Opcodes);
656 }
657 void ARMTargetELFStreamer::switchVendor(StringRef Vendor) {
658   assert(!Vendor.empty() && "Vendor cannot be empty.");
659 
660   if (CurrentVendor == Vendor)
661     return;
662 
663   if (!CurrentVendor.empty())
664     finishAttributeSection();
665 
666   assert(Contents.empty() &&
667          ".ARM.attributes should be flushed before changing vendor");
668   CurrentVendor = Vendor;
669 
670 }
671 void ARMTargetELFStreamer::emitAttribute(unsigned Attribute, unsigned Value) {
672   setAttributeItem(Attribute, Value, /* OverwriteExisting= */ true);
673 }
674 void ARMTargetELFStreamer::emitTextAttribute(unsigned Attribute,
675                                              StringRef Value) {
676   setAttributeItem(Attribute, Value, /* OverwriteExisting= */ true);
677 }
678 void ARMTargetELFStreamer::emitIntTextAttribute(unsigned Attribute,
679                                                 unsigned IntValue,
680                                                 StringRef StringValue) {
681   setAttributeItems(Attribute, IntValue, StringValue,
682                     /* OverwriteExisting= */ true);
683 }
684 void ARMTargetELFStreamer::emitArch(unsigned Value) {
685   Arch = Value;
686 }
687 void ARMTargetELFStreamer::emitObjectArch(unsigned Value) {
688   EmittedArch = Value;
689 }
690 void ARMTargetELFStreamer::emitArchDefaultAttributes() {
691   using namespace ARMBuildAttrs;
692 
693   setAttributeItem(CPU_name,
694                    ARMTargetParser::getCPUAttr(Arch),
695                    false);
696 
697   if (EmittedArch == ARM::AK_INVALID)
698     setAttributeItem(CPU_arch,
699                      ARMTargetParser::getArchAttr(Arch),
700                      false);
701   else
702     setAttributeItem(CPU_arch,
703                      ARMTargetParser::getArchAttr(EmittedArch),
704                      false);
705 
706   switch (Arch) {
707   case ARM::AK_ARMV2:
708   case ARM::AK_ARMV2A:
709   case ARM::AK_ARMV3:
710   case ARM::AK_ARMV3M:
711   case ARM::AK_ARMV4:
712   case ARM::AK_ARMV5:
713     setAttributeItem(ARM_ISA_use, Allowed, false);
714     break;
715 
716   case ARM::AK_ARMV4T:
717   case ARM::AK_ARMV5T:
718   case ARM::AK_ARMV5TE:
719   case ARM::AK_ARMV6:
720   case ARM::AK_ARMV6J:
721     setAttributeItem(ARM_ISA_use, Allowed, false);
722     setAttributeItem(THUMB_ISA_use, Allowed, false);
723     break;
724 
725   case ARM::AK_ARMV6T2:
726     setAttributeItem(ARM_ISA_use, Allowed, false);
727     setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
728     break;
729 
730   case ARM::AK_ARMV6K:
731   case ARM::AK_ARMV6Z:
732   case ARM::AK_ARMV6ZK:
733     setAttributeItem(ARM_ISA_use, Allowed, false);
734     setAttributeItem(THUMB_ISA_use, Allowed, false);
735     setAttributeItem(Virtualization_use, AllowTZ, false);
736     break;
737 
738   case ARM::AK_ARMV6M:
739     setAttributeItem(THUMB_ISA_use, Allowed, false);
740     break;
741 
742   case ARM::AK_ARMV7:
743     setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
744     break;
745 
746   case ARM::AK_ARMV7A:
747     setAttributeItem(CPU_arch_profile, ApplicationProfile, false);
748     setAttributeItem(ARM_ISA_use, Allowed, false);
749     setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
750     break;
751 
752   case ARM::AK_ARMV7R:
753     setAttributeItem(CPU_arch_profile, RealTimeProfile, false);
754     setAttributeItem(ARM_ISA_use, Allowed, false);
755     setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
756     break;
757 
758   case ARM::AK_ARMV7M:
759     setAttributeItem(CPU_arch_profile, MicroControllerProfile, false);
760     setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
761     break;
762 
763   case ARM::AK_ARMV8A:
764   case ARM::AK_ARMV8_1A:
765     setAttributeItem(CPU_arch_profile, ApplicationProfile, false);
766     setAttributeItem(ARM_ISA_use, Allowed, false);
767     setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
768     setAttributeItem(MPextension_use, Allowed, false);
769     setAttributeItem(Virtualization_use, AllowTZVirtualization, false);
770     break;
771 
772   case ARM::AK_IWMMXT:
773     setAttributeItem(ARM_ISA_use, Allowed, false);
774     setAttributeItem(THUMB_ISA_use, Allowed, false);
775     setAttributeItem(WMMX_arch, AllowWMMXv1, false);
776     break;
777 
778   case ARM::AK_IWMMXT2:
779     setAttributeItem(ARM_ISA_use, Allowed, false);
780     setAttributeItem(THUMB_ISA_use, Allowed, false);
781     setAttributeItem(WMMX_arch, AllowWMMXv2, false);
782     break;
783 
784   default:
785     report_fatal_error("Unknown Arch: " + Twine(Arch));
786     break;
787   }
788 }
789 void ARMTargetELFStreamer::emitFPU(unsigned Value) {
790   FPU = Value;
791 }
792 void ARMTargetELFStreamer::emitFPUDefaultAttributes() {
793   switch (FPU) {
794   case ARM::FK_VFP:
795   case ARM::FK_VFPV2:
796     setAttributeItem(ARMBuildAttrs::FP_arch,
797                      ARMBuildAttrs::AllowFPv2,
798                      /* OverwriteExisting= */ false);
799     break;
800 
801   case ARM::FK_VFPV3:
802     setAttributeItem(ARMBuildAttrs::FP_arch,
803                      ARMBuildAttrs::AllowFPv3A,
804                      /* OverwriteExisting= */ false);
805     break;
806 
807   case ARM::FK_VFPV3_D16:
808     setAttributeItem(ARMBuildAttrs::FP_arch,
809                      ARMBuildAttrs::AllowFPv3B,
810                      /* OverwriteExisting= */ false);
811     break;
812 
813   case ARM::FK_VFPV4:
814     setAttributeItem(ARMBuildAttrs::FP_arch,
815                      ARMBuildAttrs::AllowFPv4A,
816                      /* OverwriteExisting= */ false);
817     break;
818 
819   // ABI_HardFP_use is handled in ARMAsmPrinter, so _SP_D16 is treated the same
820   // as _D16 here.
821   case ARM::FK_FPV4_SP_D16:
822   case ARM::FK_VFPV4_D16:
823     setAttributeItem(ARMBuildAttrs::FP_arch,
824                      ARMBuildAttrs::AllowFPv4B,
825                      /* OverwriteExisting= */ false);
826     break;
827 
828   case ARM::FK_FP_ARMV8:
829     setAttributeItem(ARMBuildAttrs::FP_arch,
830                      ARMBuildAttrs::AllowFPARMv8A,
831                      /* OverwriteExisting= */ false);
832     break;
833 
834   // FPV5_D16 is identical to FP_ARMV8 except for the number of D registers, so
835   // uses the FP_ARMV8_D16 build attribute.
836   case ARM::FK_FPV5_SP_D16:
837   case ARM::FK_FPV5_D16:
838     setAttributeItem(ARMBuildAttrs::FP_arch,
839                      ARMBuildAttrs::AllowFPARMv8B,
840                      /* OverwriteExisting= */ false);
841     break;
842 
843   case ARM::FK_NEON:
844     setAttributeItem(ARMBuildAttrs::FP_arch,
845                      ARMBuildAttrs::AllowFPv3A,
846                      /* OverwriteExisting= */ false);
847     setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
848                      ARMBuildAttrs::AllowNeon,
849                      /* OverwriteExisting= */ false);
850     break;
851 
852   case ARM::FK_NEON_VFPV4:
853     setAttributeItem(ARMBuildAttrs::FP_arch,
854                      ARMBuildAttrs::AllowFPv4A,
855                      /* OverwriteExisting= */ false);
856     setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
857                      ARMBuildAttrs::AllowNeon2,
858                      /* OverwriteExisting= */ false);
859     break;
860 
861   case ARM::FK_NEON_FP_ARMV8:
862   case ARM::FK_CRYPTO_NEON_FP_ARMV8:
863     setAttributeItem(ARMBuildAttrs::FP_arch,
864                      ARMBuildAttrs::AllowFPARMv8A,
865                      /* OverwriteExisting= */ false);
866     // 'Advanced_SIMD_arch' must be emitted not here, but within
867     // ARMAsmPrinter::emitAttributes(), depending on hasV8Ops() and hasV8_1a()
868     break;
869 
870   case ARM::FK_SOFTVFP:
871   case ARM::FK_NONE:
872     break;
873 
874   default:
875     report_fatal_error("Unknown FPU: " + Twine(FPU));
876     break;
877   }
878 }
879 size_t ARMTargetELFStreamer::calculateContentSize() const {
880   size_t Result = 0;
881   for (size_t i = 0; i < Contents.size(); ++i) {
882     AttributeItem item = Contents[i];
883     switch (item.Type) {
884     case AttributeItem::HiddenAttribute:
885       break;
886     case AttributeItem::NumericAttribute:
887       Result += getULEB128Size(item.Tag);
888       Result += getULEB128Size(item.IntValue);
889       break;
890     case AttributeItem::TextAttribute:
891       Result += getULEB128Size(item.Tag);
892       Result += item.StringValue.size() + 1; // string + '\0'
893       break;
894     case AttributeItem::NumericAndTextAttributes:
895       Result += getULEB128Size(item.Tag);
896       Result += getULEB128Size(item.IntValue);
897       Result += item.StringValue.size() + 1; // string + '\0';
898       break;
899     }
900   }
901   return Result;
902 }
903 void ARMTargetELFStreamer::finishAttributeSection() {
904   // <format-version>
905   // [ <section-length> "vendor-name"
906   // [ <file-tag> <size> <attribute>*
907   //   | <section-tag> <size> <section-number>* 0 <attribute>*
908   //   | <symbol-tag> <size> <symbol-number>* 0 <attribute>*
909   //   ]+
910   // ]*
911 
912   if (FPU != ARM::FK_INVALID)
913     emitFPUDefaultAttributes();
914 
915   if (Arch != ARM::AK_INVALID)
916     emitArchDefaultAttributes();
917 
918   if (Contents.empty())
919     return;
920 
921   std::sort(Contents.begin(), Contents.end(), AttributeItem::LessTag);
922 
923   ARMELFStreamer &Streamer = getStreamer();
924 
925   // Switch to .ARM.attributes section
926   if (AttributeSection) {
927     Streamer.SwitchSection(AttributeSection);
928   } else {
929     AttributeSection = Streamer.getContext().getELFSection(
930         ".ARM.attributes", ELF::SHT_ARM_ATTRIBUTES, 0);
931     Streamer.SwitchSection(AttributeSection);
932 
933     // Format version
934     Streamer.EmitIntValue(0x41, 1);
935   }
936 
937   // Vendor size + Vendor name + '\0'
938   const size_t VendorHeaderSize = 4 + CurrentVendor.size() + 1;
939 
940   // Tag + Tag Size
941   const size_t TagHeaderSize = 1 + 4;
942 
943   const size_t ContentsSize = calculateContentSize();
944 
945   Streamer.EmitIntValue(VendorHeaderSize + TagHeaderSize + ContentsSize, 4);
946   Streamer.EmitBytes(CurrentVendor);
947   Streamer.EmitIntValue(0, 1); // '\0'
948 
949   Streamer.EmitIntValue(ARMBuildAttrs::File, 1);
950   Streamer.EmitIntValue(TagHeaderSize + ContentsSize, 4);
951 
952   // Size should have been accounted for already, now
953   // emit each field as its type (ULEB or String)
954   for (size_t i = 0; i < Contents.size(); ++i) {
955     AttributeItem item = Contents[i];
956     Streamer.EmitULEB128IntValue(item.Tag);
957     switch (item.Type) {
958     default: llvm_unreachable("Invalid attribute type");
959     case AttributeItem::NumericAttribute:
960       Streamer.EmitULEB128IntValue(item.IntValue);
961       break;
962     case AttributeItem::TextAttribute:
963       Streamer.EmitBytes(item.StringValue);
964       Streamer.EmitIntValue(0, 1); // '\0'
965       break;
966     case AttributeItem::NumericAndTextAttributes:
967       Streamer.EmitULEB128IntValue(item.IntValue);
968       Streamer.EmitBytes(item.StringValue);
969       Streamer.EmitIntValue(0, 1); // '\0'
970       break;
971     }
972   }
973 
974   Contents.clear();
975   FPU = ARM::FK_INVALID;
976 }
977 
978 void ARMTargetELFStreamer::emitLabel(MCSymbol *Symbol) {
979   ARMELFStreamer &Streamer = getStreamer();
980   if (!Streamer.IsThumb)
981     return;
982 
983   Streamer.getAssembler().registerSymbol(*Symbol);
984   unsigned Type = cast<MCSymbolELF>(Symbol)->getType();
985   if (Type == ELF::STT_FUNC || Type == ELF::STT_GNU_IFUNC)
986     Streamer.EmitThumbFunc(Symbol);
987 }
988 
989 void
990 ARMTargetELFStreamer::AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *S) {
991   getStreamer().EmitFixup(S, FK_Data_4);
992 }
993 
994 void ARMTargetELFStreamer::emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) {
995   if (const MCSymbolRefExpr *SRE = dyn_cast<MCSymbolRefExpr>(Value)) {
996     const MCSymbol &Sym = SRE->getSymbol();
997     if (!Sym.isDefined()) {
998       getStreamer().EmitAssignment(Symbol, Value);
999       return;
1000     }
1001   }
1002 
1003   getStreamer().EmitThumbFunc(Symbol);
1004   getStreamer().EmitAssignment(Symbol, Value);
1005 }
1006 
1007 void ARMTargetELFStreamer::emitInst(uint32_t Inst, char Suffix) {
1008   getStreamer().emitInst(Inst, Suffix);
1009 }
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 inline void ARMELFStreamer::SwitchToEHSection(const char *Prefix,
1020                                               unsigned Type,
1021                                               unsigned Flags,
1022                                               SectionKind Kind,
1023                                               const MCSymbol &Fn) {
1024   const MCSectionELF &FnSection =
1025     static_cast<const MCSectionELF &>(Fn.getSection());
1026 
1027   // Create the name for new section
1028   StringRef FnSecName(FnSection.getSectionName());
1029   SmallString<128> EHSecName(Prefix);
1030   if (FnSecName != ".text") {
1031     EHSecName += FnSecName;
1032   }
1033 
1034   // Get .ARM.extab or .ARM.exidx section
1035   const MCSymbolELF *Group = FnSection.getGroup();
1036   if (Group)
1037     Flags |= ELF::SHF_GROUP;
1038   MCSectionELF *EHSection =
1039       getContext().getELFSection(EHSecName, Type, Flags, 0, Group,
1040                                  FnSection.getUniqueID(), nullptr, &FnSection);
1041 
1042   assert(EHSection && "Failed to get the required EH section");
1043 
1044   // Switch to .ARM.extab or .ARM.exidx section
1045   SwitchSection(EHSection);
1046   EmitCodeAlignment(4);
1047 }
1048 
1049 inline void ARMELFStreamer::SwitchToExTabSection(const MCSymbol &FnStart) {
1050   SwitchToEHSection(".ARM.extab",
1051                     ELF::SHT_PROGBITS,
1052                     ELF::SHF_ALLOC,
1053                     SectionKind::getDataRel(),
1054                     FnStart);
1055 }
1056 
1057 inline void ARMELFStreamer::SwitchToExIdxSection(const MCSymbol &FnStart) {
1058   SwitchToEHSection(".ARM.exidx",
1059                     ELF::SHT_ARM_EXIDX,
1060                     ELF::SHF_ALLOC | ELF::SHF_LINK_ORDER,
1061                     SectionKind::getDataRel(),
1062                     FnStart);
1063 }
1064 void ARMELFStreamer::EmitFixup(const MCExpr *Expr, MCFixupKind Kind) {
1065   MCDataFragment *Frag = getOrCreateDataFragment();
1066   Frag->getFixups().push_back(MCFixup::create(Frag->getContents().size(), Expr,
1067                                               Kind));
1068 }
1069 
1070 void ARMELFStreamer::Reset() {
1071   ExTab = nullptr;
1072   FnStart = nullptr;
1073   Personality = nullptr;
1074   PersonalityIndex = ARM::EHABI::NUM_PERSONALITY_INDEX;
1075   FPReg = ARM::SP;
1076   FPOffset = 0;
1077   SPOffset = 0;
1078   PendingOffset = 0;
1079   UsedFP = false;
1080   CantUnwind = false;
1081 
1082   Opcodes.clear();
1083   UnwindOpAsm.Reset();
1084 }
1085 
1086 void ARMELFStreamer::emitFnStart() {
1087   assert(FnStart == nullptr);
1088   FnStart = getContext().createTempSymbol();
1089   EmitLabel(FnStart);
1090 }
1091 
1092 void ARMELFStreamer::emitFnEnd() {
1093   assert(FnStart && ".fnstart must precedes .fnend");
1094 
1095   // Emit unwind opcodes if there is no .handlerdata directive
1096   if (!ExTab && !CantUnwind)
1097     FlushUnwindOpcodes(true);
1098 
1099   // Emit the exception index table entry
1100   SwitchToExIdxSection(*FnStart);
1101 
1102   if (PersonalityIndex < ARM::EHABI::NUM_PERSONALITY_INDEX)
1103     EmitPersonalityFixup(GetAEABIUnwindPersonalityName(PersonalityIndex));
1104 
1105   const MCSymbolRefExpr *FnStartRef =
1106     MCSymbolRefExpr::create(FnStart,
1107                             MCSymbolRefExpr::VK_ARM_PREL31,
1108                             getContext());
1109 
1110   EmitValue(FnStartRef, 4);
1111 
1112   if (CantUnwind) {
1113     EmitIntValue(ARM::EHABI::EXIDX_CANTUNWIND, 4);
1114   } else if (ExTab) {
1115     // Emit a reference to the unwind opcodes in the ".ARM.extab" section.
1116     const MCSymbolRefExpr *ExTabEntryRef =
1117       MCSymbolRefExpr::create(ExTab,
1118                               MCSymbolRefExpr::VK_ARM_PREL31,
1119                               getContext());
1120     EmitValue(ExTabEntryRef, 4);
1121   } else {
1122     // For the __aeabi_unwind_cpp_pr0, we have to emit the unwind opcodes in
1123     // the second word of exception index table entry.  The size of the unwind
1124     // opcodes should always be 4 bytes.
1125     assert(PersonalityIndex == ARM::EHABI::AEABI_UNWIND_CPP_PR0 &&
1126            "Compact model must use __aeabi_unwind_cpp_pr0 as personality");
1127     assert(Opcodes.size() == 4u &&
1128            "Unwind opcode size for __aeabi_unwind_cpp_pr0 must be equal to 4");
1129     uint64_t Intval = Opcodes[0] |
1130                       Opcodes[1] << 8 |
1131                       Opcodes[2] << 16 |
1132                       Opcodes[3] << 24;
1133     EmitIntValue(Intval, Opcodes.size());
1134   }
1135 
1136   // Switch to the section containing FnStart
1137   SwitchSection(&FnStart->getSection());
1138 
1139   // Clean exception handling frame information
1140   Reset();
1141 }
1142 
1143 void ARMELFStreamer::emitCantUnwind() { CantUnwind = true; }
1144 
1145 // Add the R_ARM_NONE fixup at the same position
1146 void ARMELFStreamer::EmitPersonalityFixup(StringRef Name) {
1147   const MCSymbol *PersonalitySym = getContext().getOrCreateSymbol(Name);
1148 
1149   const MCSymbolRefExpr *PersonalityRef = MCSymbolRefExpr::create(
1150       PersonalitySym, MCSymbolRefExpr::VK_ARM_NONE, getContext());
1151 
1152   visitUsedExpr(*PersonalityRef);
1153   MCDataFragment *DF = getOrCreateDataFragment();
1154   DF->getFixups().push_back(MCFixup::create(DF->getContents().size(),
1155                                             PersonalityRef,
1156                                             MCFixup::getKindForSize(4, false)));
1157 }
1158 
1159 void ARMELFStreamer::FlushPendingOffset() {
1160   if (PendingOffset != 0) {
1161     UnwindOpAsm.EmitSPOffset(-PendingOffset);
1162     PendingOffset = 0;
1163   }
1164 }
1165 
1166 void ARMELFStreamer::FlushUnwindOpcodes(bool NoHandlerData) {
1167   // Emit the unwind opcode to restore $sp.
1168   if (UsedFP) {
1169     const MCRegisterInfo *MRI = getContext().getRegisterInfo();
1170     int64_t LastRegSaveSPOffset = SPOffset - PendingOffset;
1171     UnwindOpAsm.EmitSPOffset(LastRegSaveSPOffset - FPOffset);
1172     UnwindOpAsm.EmitSetSP(MRI->getEncodingValue(FPReg));
1173   } else {
1174     FlushPendingOffset();
1175   }
1176 
1177   // Finalize the unwind opcode sequence
1178   UnwindOpAsm.Finalize(PersonalityIndex, Opcodes);
1179 
1180   // For compact model 0, we have to emit the unwind opcodes in the .ARM.exidx
1181   // section.  Thus, we don't have to create an entry in the .ARM.extab
1182   // section.
1183   if (NoHandlerData && PersonalityIndex == ARM::EHABI::AEABI_UNWIND_CPP_PR0)
1184     return;
1185 
1186   // Switch to .ARM.extab section.
1187   SwitchToExTabSection(*FnStart);
1188 
1189   // Create .ARM.extab label for offset in .ARM.exidx
1190   assert(!ExTab);
1191   ExTab = getContext().createTempSymbol();
1192   EmitLabel(ExTab);
1193 
1194   // Emit personality
1195   if (Personality) {
1196     const MCSymbolRefExpr *PersonalityRef =
1197       MCSymbolRefExpr::create(Personality,
1198                               MCSymbolRefExpr::VK_ARM_PREL31,
1199                               getContext());
1200 
1201     EmitValue(PersonalityRef, 4);
1202   }
1203 
1204   // Emit unwind opcodes
1205   assert((Opcodes.size() % 4) == 0 &&
1206          "Unwind opcode size for __aeabi_cpp_unwind_pr0 must be multiple of 4");
1207   for (unsigned I = 0; I != Opcodes.size(); I += 4) {
1208     uint64_t Intval = Opcodes[I] |
1209                       Opcodes[I + 1] << 8 |
1210                       Opcodes[I + 2] << 16 |
1211                       Opcodes[I + 3] << 24;
1212     EmitIntValue(Intval, 4);
1213   }
1214 
1215   // According to ARM EHABI section 9.2, if the __aeabi_unwind_cpp_pr1() or
1216   // __aeabi_unwind_cpp_pr2() is used, then the handler data must be emitted
1217   // after the unwind opcodes.  The handler data consists of several 32-bit
1218   // words, and should be terminated by zero.
1219   //
1220   // In case that the .handlerdata directive is not specified by the
1221   // programmer, we should emit zero to terminate the handler data.
1222   if (NoHandlerData && !Personality)
1223     EmitIntValue(0, 4);
1224 }
1225 
1226 void ARMELFStreamer::emitHandlerData() { FlushUnwindOpcodes(false); }
1227 
1228 void ARMELFStreamer::emitPersonality(const MCSymbol *Per) {
1229   Personality = Per;
1230   UnwindOpAsm.setPersonality(Per);
1231 }
1232 
1233 void ARMELFStreamer::emitPersonalityIndex(unsigned Index) {
1234   assert(Index < ARM::EHABI::NUM_PERSONALITY_INDEX && "invalid index");
1235   PersonalityIndex = Index;
1236 }
1237 
1238 void ARMELFStreamer::emitSetFP(unsigned NewFPReg, unsigned NewSPReg,
1239                                int64_t Offset) {
1240   assert((NewSPReg == ARM::SP || NewSPReg == FPReg) &&
1241          "the operand of .setfp directive should be either $sp or $fp");
1242 
1243   UsedFP = true;
1244   FPReg = NewFPReg;
1245 
1246   if (NewSPReg == ARM::SP)
1247     FPOffset = SPOffset + Offset;
1248   else
1249     FPOffset += Offset;
1250 }
1251 
1252 void ARMELFStreamer::emitMovSP(unsigned Reg, int64_t Offset) {
1253   assert((Reg != ARM::SP && Reg != ARM::PC) &&
1254          "the operand of .movsp cannot be either sp or pc");
1255   assert(FPReg == ARM::SP && "current FP must be SP");
1256 
1257   FlushPendingOffset();
1258 
1259   FPReg = Reg;
1260   FPOffset = SPOffset + Offset;
1261 
1262   const MCRegisterInfo *MRI = getContext().getRegisterInfo();
1263   UnwindOpAsm.EmitSetSP(MRI->getEncodingValue(FPReg));
1264 }
1265 
1266 void ARMELFStreamer::emitPad(int64_t Offset) {
1267   // Track the change of the $sp offset
1268   SPOffset -= Offset;
1269 
1270   // To squash multiple .pad directives, we should delay the unwind opcode
1271   // until the .save, .vsave, .handlerdata, or .fnend directives.
1272   PendingOffset -= Offset;
1273 }
1274 
1275 void ARMELFStreamer::emitRegSave(const SmallVectorImpl<unsigned> &RegList,
1276                                  bool IsVector) {
1277   // Collect the registers in the register list
1278   unsigned Count = 0;
1279   uint32_t Mask = 0;
1280   const MCRegisterInfo *MRI = getContext().getRegisterInfo();
1281   for (size_t i = 0; i < RegList.size(); ++i) {
1282     unsigned Reg = MRI->getEncodingValue(RegList[i]);
1283     assert(Reg < (IsVector ? 32U : 16U) && "Register out of range");
1284     unsigned Bit = (1u << Reg);
1285     if ((Mask & Bit) == 0) {
1286       Mask |= Bit;
1287       ++Count;
1288     }
1289   }
1290 
1291   // Track the change the $sp offset: For the .save directive, the
1292   // corresponding push instruction will decrease the $sp by (4 * Count).
1293   // For the .vsave directive, the corresponding vpush instruction will
1294   // decrease $sp by (8 * Count).
1295   SPOffset -= Count * (IsVector ? 8 : 4);
1296 
1297   // Emit the opcode
1298   FlushPendingOffset();
1299   if (IsVector)
1300     UnwindOpAsm.EmitVFPRegSave(Mask);
1301   else
1302     UnwindOpAsm.EmitRegSave(Mask);
1303 }
1304 
1305 void ARMELFStreamer::emitUnwindRaw(int64_t Offset,
1306                                    const SmallVectorImpl<uint8_t> &Opcodes) {
1307   FlushPendingOffset();
1308   SPOffset = SPOffset - Offset;
1309   UnwindOpAsm.EmitRaw(Opcodes);
1310 }
1311 
1312 namespace llvm {
1313 
1314 MCTargetStreamer *createARMTargetAsmStreamer(MCStreamer &S,
1315                                              formatted_raw_ostream &OS,
1316                                              MCInstPrinter *InstPrint,
1317                                              bool isVerboseAsm) {
1318   return new ARMTargetAsmStreamer(S, OS, *InstPrint, isVerboseAsm);
1319 }
1320 
1321 MCTargetStreamer *createARMNullTargetStreamer(MCStreamer &S) {
1322   return new ARMTargetStreamer(S);
1323 }
1324 
1325 MCTargetStreamer *createARMObjectTargetStreamer(MCStreamer &S,
1326                                                 const MCSubtargetInfo &STI) {
1327   Triple TT(STI.getTargetTriple());
1328   if (TT.getObjectFormat() == Triple::ELF)
1329     return new ARMTargetELFStreamer(S);
1330   return new ARMTargetStreamer(S);
1331 }
1332 
1333 MCELFStreamer *createARMELFStreamer(MCContext &Context, MCAsmBackend &TAB,
1334                                     raw_pwrite_stream &OS,
1335                                     MCCodeEmitter *Emitter, bool RelaxAll,
1336                                     bool IsThumb) {
1337     ARMELFStreamer *S = new ARMELFStreamer(Context, TAB, OS, Emitter, IsThumb);
1338     // FIXME: This should eventually end up somewhere else where more
1339     // intelligent flag decisions can be made. For now we are just maintaining
1340     // the status quo for ARM and setting EF_ARM_EABI_VER5 as the default.
1341     S->getAssembler().setELFHeaderEFlags(ELF::EF_ARM_EABI_VER5);
1342 
1343     if (RelaxAll)
1344       S->getAssembler().setRelaxAll(true);
1345     return S;
1346   }
1347 
1348 }
1349 
1350 
1351