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" << ARM::getArchName(Arch) << "\n";
199 }
200 void ARMTargetAsmStreamer::emitArchExtension(unsigned ArchExt) {
201   OS << "\t.arch_extension\t" << ARM::getArchExtName(ArchExt) << "\n";
202 }
203 void ARMTargetAsmStreamer::emitObjectArch(unsigned Arch) {
204   OS << "\t.object_arch\t" << ARM::getArchName(Arch) << '\n';
205 }
206 void ARMTargetAsmStreamer::emitFPU(unsigned FPU) {
207   OS << "\t.fpu\t" << ARM::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 ($d) if
509   /// necessary.
510   void EmitValueImpl(const MCExpr *Value, unsigned Size, SMLoc Loc) override {
511     if (const MCSymbolRefExpr *SRE = dyn_cast_or_null<MCSymbolRefExpr>(Value))
512       if (SRE->getKind() == MCSymbolRefExpr::VK_ARM_SBREL && !(Size == 4)) {
513         getContext().reportError(Loc, "relocated expression must be 32-bit");
514         return;
515       }
516 
517     EmitDataMappingSymbol();
518     MCELFStreamer::EmitValueImpl(Value, Size, Loc);
519   }
520 
521   void EmitAssemblerFlag(MCAssemblerFlag Flag) override {
522     MCELFStreamer::EmitAssemblerFlag(Flag);
523 
524     switch (Flag) {
525     case MCAF_SyntaxUnified:
526       return; // no-op here.
527     case MCAF_Code16:
528       IsThumb = true;
529       return; // Change to Thumb mode
530     case MCAF_Code32:
531       IsThumb = false;
532       return; // Change to ARM mode
533     case MCAF_Code64:
534       return;
535     case MCAF_SubsectionsViaSymbols:
536       return;
537     }
538   }
539 
540 private:
541   enum ElfMappingSymbol {
542     EMS_None,
543     EMS_ARM,
544     EMS_Thumb,
545     EMS_Data
546   };
547 
548   void EmitDataMappingSymbol() {
549     if (LastEMS == EMS_Data) return;
550     EmitMappingSymbol("$d");
551     LastEMS = EMS_Data;
552   }
553 
554   void EmitThumbMappingSymbol() {
555     if (LastEMS == EMS_Thumb) return;
556     EmitMappingSymbol("$t");
557     LastEMS = EMS_Thumb;
558   }
559 
560   void EmitARMMappingSymbol() {
561     if (LastEMS == EMS_ARM) return;
562     EmitMappingSymbol("$a");
563     LastEMS = EMS_ARM;
564   }
565 
566   void EmitMappingSymbol(StringRef Name) {
567     auto *Symbol = cast<MCSymbolELF>(getContext().getOrCreateSymbol(
568         Name + "." + Twine(MappingSymbolCounter++)));
569     EmitLabel(Symbol);
570 
571     Symbol->setType(ELF::STT_NOTYPE);
572     Symbol->setBinding(ELF::STB_LOCAL);
573     Symbol->setExternal(false);
574   }
575 
576   void EmitThumbFunc(MCSymbol *Func) override {
577     getAssembler().setIsThumbFunc(Func);
578     EmitSymbolAttribute(Func, MCSA_ELF_TypeFunction);
579   }
580 
581   // Helper functions for ARM exception handling directives
582   void Reset();
583 
584   void EmitPersonalityFixup(StringRef Name);
585   void FlushPendingOffset();
586   void FlushUnwindOpcodes(bool NoHandlerData);
587 
588   void SwitchToEHSection(const char *Prefix, unsigned Type, unsigned Flags,
589                          SectionKind Kind, const MCSymbol &Fn);
590   void SwitchToExTabSection(const MCSymbol &FnStart);
591   void SwitchToExIdxSection(const MCSymbol &FnStart);
592 
593   void EmitFixup(const MCExpr *Expr, MCFixupKind Kind);
594 
595   bool IsThumb;
596   int64_t MappingSymbolCounter;
597 
598   DenseMap<const MCSection *, ElfMappingSymbol> LastMappingSymbols;
599   ElfMappingSymbol LastEMS;
600 
601   // ARM Exception Handling Frame Information
602   MCSymbol *ExTab;
603   MCSymbol *FnStart;
604   const MCSymbol *Personality;
605   unsigned PersonalityIndex;
606   unsigned FPReg; // Frame pointer register
607   int64_t FPOffset; // Offset: (final frame pointer) - (initial $sp)
608   int64_t SPOffset; // Offset: (final $sp) - (initial $sp)
609   int64_t PendingOffset; // Offset: (final $sp) - (emitted $sp)
610   bool UsedFP;
611   bool CantUnwind;
612   SmallVector<uint8_t, 64> Opcodes;
613   UnwindOpcodeAssembler UnwindOpAsm;
614 };
615 } // end anonymous namespace
616 
617 ARMELFStreamer &ARMTargetELFStreamer::getStreamer() {
618   return static_cast<ARMELFStreamer &>(Streamer);
619 }
620 
621 void ARMTargetELFStreamer::emitFnStart() { getStreamer().emitFnStart(); }
622 void ARMTargetELFStreamer::emitFnEnd() { getStreamer().emitFnEnd(); }
623 void ARMTargetELFStreamer::emitCantUnwind() { getStreamer().emitCantUnwind(); }
624 void ARMTargetELFStreamer::emitPersonality(const MCSymbol *Personality) {
625   getStreamer().emitPersonality(Personality);
626 }
627 void ARMTargetELFStreamer::emitPersonalityIndex(unsigned Index) {
628   getStreamer().emitPersonalityIndex(Index);
629 }
630 void ARMTargetELFStreamer::emitHandlerData() {
631   getStreamer().emitHandlerData();
632 }
633 void ARMTargetELFStreamer::emitSetFP(unsigned FpReg, unsigned SpReg,
634                                      int64_t Offset) {
635   getStreamer().emitSetFP(FpReg, SpReg, Offset);
636 }
637 void ARMTargetELFStreamer::emitMovSP(unsigned Reg, int64_t Offset) {
638   getStreamer().emitMovSP(Reg, Offset);
639 }
640 void ARMTargetELFStreamer::emitPad(int64_t Offset) {
641   getStreamer().emitPad(Offset);
642 }
643 void ARMTargetELFStreamer::emitRegSave(const SmallVectorImpl<unsigned> &RegList,
644                                        bool isVector) {
645   getStreamer().emitRegSave(RegList, isVector);
646 }
647 void ARMTargetELFStreamer::emitUnwindRaw(int64_t Offset,
648                                       const SmallVectorImpl<uint8_t> &Opcodes) {
649   getStreamer().emitUnwindRaw(Offset, Opcodes);
650 }
651 void ARMTargetELFStreamer::switchVendor(StringRef Vendor) {
652   assert(!Vendor.empty() && "Vendor cannot be empty.");
653 
654   if (CurrentVendor == Vendor)
655     return;
656 
657   if (!CurrentVendor.empty())
658     finishAttributeSection();
659 
660   assert(Contents.empty() &&
661          ".ARM.attributes should be flushed before changing vendor");
662   CurrentVendor = Vendor;
663 
664 }
665 void ARMTargetELFStreamer::emitAttribute(unsigned Attribute, unsigned Value) {
666   setAttributeItem(Attribute, Value, /* OverwriteExisting= */ true);
667 }
668 void ARMTargetELFStreamer::emitTextAttribute(unsigned Attribute,
669                                              StringRef Value) {
670   setAttributeItem(Attribute, Value, /* OverwriteExisting= */ true);
671 }
672 void ARMTargetELFStreamer::emitIntTextAttribute(unsigned Attribute,
673                                                 unsigned IntValue,
674                                                 StringRef StringValue) {
675   setAttributeItems(Attribute, IntValue, StringValue,
676                     /* OverwriteExisting= */ true);
677 }
678 void ARMTargetELFStreamer::emitArch(unsigned Value) {
679   Arch = Value;
680 }
681 void ARMTargetELFStreamer::emitObjectArch(unsigned Value) {
682   EmittedArch = Value;
683 }
684 void ARMTargetELFStreamer::emitArchDefaultAttributes() {
685   using namespace ARMBuildAttrs;
686 
687   setAttributeItem(CPU_name,
688                    ARM::getCPUAttr(Arch),
689                    false);
690 
691   if (EmittedArch == ARM::AK_INVALID)
692     setAttributeItem(CPU_arch,
693                      ARM::getArchAttr(Arch),
694                      false);
695   else
696     setAttributeItem(CPU_arch,
697                      ARM::getArchAttr(EmittedArch),
698                      false);
699 
700   switch (Arch) {
701   case ARM::AK_ARMV2:
702   case ARM::AK_ARMV2A:
703   case ARM::AK_ARMV3:
704   case ARM::AK_ARMV3M:
705   case ARM::AK_ARMV4:
706     setAttributeItem(ARM_ISA_use, Allowed, false);
707     break;
708 
709   case ARM::AK_ARMV4T:
710   case ARM::AK_ARMV5T:
711   case ARM::AK_ARMV5TE:
712   case ARM::AK_ARMV6:
713     setAttributeItem(ARM_ISA_use, Allowed, false);
714     setAttributeItem(THUMB_ISA_use, Allowed, false);
715     break;
716 
717   case ARM::AK_ARMV6T2:
718     setAttributeItem(ARM_ISA_use, Allowed, false);
719     setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
720     break;
721 
722   case ARM::AK_ARMV6K:
723   case ARM::AK_ARMV6KZ:
724     setAttributeItem(ARM_ISA_use, Allowed, false);
725     setAttributeItem(THUMB_ISA_use, Allowed, false);
726     setAttributeItem(Virtualization_use, AllowTZ, false);
727     break;
728 
729   case ARM::AK_ARMV6M:
730     setAttributeItem(THUMB_ISA_use, Allowed, false);
731     break;
732 
733   case ARM::AK_ARMV7A:
734     setAttributeItem(CPU_arch_profile, ApplicationProfile, false);
735     setAttributeItem(ARM_ISA_use, Allowed, false);
736     setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
737     break;
738 
739   case ARM::AK_ARMV7R:
740     setAttributeItem(CPU_arch_profile, RealTimeProfile, false);
741     setAttributeItem(ARM_ISA_use, Allowed, false);
742     setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
743     break;
744 
745   case ARM::AK_ARMV7M:
746     setAttributeItem(CPU_arch_profile, MicroControllerProfile, false);
747     setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
748     break;
749 
750   case ARM::AK_ARMV8A:
751   case ARM::AK_ARMV8_1A:
752     setAttributeItem(CPU_arch_profile, ApplicationProfile, false);
753     setAttributeItem(ARM_ISA_use, Allowed, false);
754     setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
755     setAttributeItem(MPextension_use, Allowed, false);
756     setAttributeItem(Virtualization_use, AllowTZVirtualization, false);
757     break;
758 
759   case ARM::AK_IWMMXT:
760     setAttributeItem(ARM_ISA_use, Allowed, false);
761     setAttributeItem(THUMB_ISA_use, Allowed, false);
762     setAttributeItem(WMMX_arch, AllowWMMXv1, false);
763     break;
764 
765   case ARM::AK_IWMMXT2:
766     setAttributeItem(ARM_ISA_use, Allowed, false);
767     setAttributeItem(THUMB_ISA_use, Allowed, false);
768     setAttributeItem(WMMX_arch, AllowWMMXv2, false);
769     break;
770 
771   default:
772     report_fatal_error("Unknown Arch: " + Twine(Arch));
773     break;
774   }
775 }
776 void ARMTargetELFStreamer::emitFPU(unsigned Value) {
777   FPU = Value;
778 }
779 void ARMTargetELFStreamer::emitFPUDefaultAttributes() {
780   switch (FPU) {
781   case ARM::FK_VFP:
782   case ARM::FK_VFPV2:
783     setAttributeItem(ARMBuildAttrs::FP_arch,
784                      ARMBuildAttrs::AllowFPv2,
785                      /* OverwriteExisting= */ false);
786     break;
787 
788   case ARM::FK_VFPV3:
789     setAttributeItem(ARMBuildAttrs::FP_arch,
790                      ARMBuildAttrs::AllowFPv3A,
791                      /* OverwriteExisting= */ false);
792     break;
793 
794   case ARM::FK_VFPV3_FP16:
795     setAttributeItem(ARMBuildAttrs::FP_arch,
796                      ARMBuildAttrs::AllowFPv3A,
797                      /* OverwriteExisting= */ false);
798     setAttributeItem(ARMBuildAttrs::FP_HP_extension,
799                      ARMBuildAttrs::AllowHPFP,
800                      /* OverwriteExisting= */ false);
801     break;
802 
803   case ARM::FK_VFPV3_D16:
804     setAttributeItem(ARMBuildAttrs::FP_arch,
805                      ARMBuildAttrs::AllowFPv3B,
806                      /* OverwriteExisting= */ false);
807     break;
808 
809   case ARM::FK_VFPV3_D16_FP16:
810     setAttributeItem(ARMBuildAttrs::FP_arch,
811                      ARMBuildAttrs::AllowFPv3B,
812                      /* OverwriteExisting= */ false);
813     setAttributeItem(ARMBuildAttrs::FP_HP_extension,
814                      ARMBuildAttrs::AllowHPFP,
815                      /* OverwriteExisting= */ false);
816     break;
817 
818   case ARM::FK_VFPV3XD:
819     setAttributeItem(ARMBuildAttrs::FP_arch,
820                      ARMBuildAttrs::AllowFPv3B,
821                      /* OverwriteExisting= */ false);
822     break;
823   case ARM::FK_VFPV3XD_FP16:
824     setAttributeItem(ARMBuildAttrs::FP_arch,
825                      ARMBuildAttrs::AllowFPv3B,
826                      /* OverwriteExisting= */ false);
827     setAttributeItem(ARMBuildAttrs::FP_HP_extension,
828                      ARMBuildAttrs::AllowHPFP,
829                      /* OverwriteExisting= */ false);
830     break;
831 
832   case ARM::FK_VFPV4:
833     setAttributeItem(ARMBuildAttrs::FP_arch,
834                      ARMBuildAttrs::AllowFPv4A,
835                      /* OverwriteExisting= */ false);
836     break;
837 
838   // ABI_HardFP_use is handled in ARMAsmPrinter, so _SP_D16 is treated the same
839   // as _D16 here.
840   case ARM::FK_FPV4_SP_D16:
841   case ARM::FK_VFPV4_D16:
842     setAttributeItem(ARMBuildAttrs::FP_arch,
843                      ARMBuildAttrs::AllowFPv4B,
844                      /* OverwriteExisting= */ false);
845     break;
846 
847   case ARM::FK_FP_ARMV8:
848     setAttributeItem(ARMBuildAttrs::FP_arch,
849                      ARMBuildAttrs::AllowFPARMv8A,
850                      /* OverwriteExisting= */ false);
851     break;
852 
853   // FPV5_D16 is identical to FP_ARMV8 except for the number of D registers, so
854   // uses the FP_ARMV8_D16 build attribute.
855   case ARM::FK_FPV5_SP_D16:
856   case ARM::FK_FPV5_D16:
857     setAttributeItem(ARMBuildAttrs::FP_arch,
858                      ARMBuildAttrs::AllowFPARMv8B,
859                      /* OverwriteExisting= */ false);
860     break;
861 
862   case ARM::FK_NEON:
863     setAttributeItem(ARMBuildAttrs::FP_arch,
864                      ARMBuildAttrs::AllowFPv3A,
865                      /* OverwriteExisting= */ false);
866     setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
867                      ARMBuildAttrs::AllowNeon,
868                      /* OverwriteExisting= */ false);
869     break;
870 
871   case ARM::FK_NEON_FP16:
872     setAttributeItem(ARMBuildAttrs::FP_arch,
873                      ARMBuildAttrs::AllowFPv3A,
874                      /* OverwriteExisting= */ false);
875     setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
876                      ARMBuildAttrs::AllowNeon,
877                      /* OverwriteExisting= */ false);
878     setAttributeItem(ARMBuildAttrs::FP_HP_extension,
879                      ARMBuildAttrs::AllowHPFP,
880                      /* OverwriteExisting= */ false);
881     break;
882 
883   case ARM::FK_NEON_VFPV4:
884     setAttributeItem(ARMBuildAttrs::FP_arch,
885                      ARMBuildAttrs::AllowFPv4A,
886                      /* OverwriteExisting= */ false);
887     setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
888                      ARMBuildAttrs::AllowNeon2,
889                      /* OverwriteExisting= */ false);
890     break;
891 
892   case ARM::FK_NEON_FP_ARMV8:
893   case ARM::FK_CRYPTO_NEON_FP_ARMV8:
894     setAttributeItem(ARMBuildAttrs::FP_arch,
895                      ARMBuildAttrs::AllowFPARMv8A,
896                      /* OverwriteExisting= */ false);
897     // 'Advanced_SIMD_arch' must be emitted not here, but within
898     // ARMAsmPrinter::emitAttributes(), depending on hasV8Ops() and hasV8_1a()
899     break;
900 
901   case ARM::FK_SOFTVFP:
902   case ARM::FK_NONE:
903     break;
904 
905   default:
906     report_fatal_error("Unknown FPU: " + Twine(FPU));
907     break;
908   }
909 }
910 size_t ARMTargetELFStreamer::calculateContentSize() const {
911   size_t Result = 0;
912   for (size_t i = 0; i < Contents.size(); ++i) {
913     AttributeItem item = Contents[i];
914     switch (item.Type) {
915     case AttributeItem::HiddenAttribute:
916       break;
917     case AttributeItem::NumericAttribute:
918       Result += getULEB128Size(item.Tag);
919       Result += getULEB128Size(item.IntValue);
920       break;
921     case AttributeItem::TextAttribute:
922       Result += getULEB128Size(item.Tag);
923       Result += item.StringValue.size() + 1; // string + '\0'
924       break;
925     case AttributeItem::NumericAndTextAttributes:
926       Result += getULEB128Size(item.Tag);
927       Result += getULEB128Size(item.IntValue);
928       Result += item.StringValue.size() + 1; // string + '\0';
929       break;
930     }
931   }
932   return Result;
933 }
934 void ARMTargetELFStreamer::finishAttributeSection() {
935   // <format-version>
936   // [ <section-length> "vendor-name"
937   // [ <file-tag> <size> <attribute>*
938   //   | <section-tag> <size> <section-number>* 0 <attribute>*
939   //   | <symbol-tag> <size> <symbol-number>* 0 <attribute>*
940   //   ]+
941   // ]*
942 
943   if (FPU != ARM::FK_INVALID)
944     emitFPUDefaultAttributes();
945 
946   if (Arch != ARM::AK_INVALID)
947     emitArchDefaultAttributes();
948 
949   if (Contents.empty())
950     return;
951 
952   std::sort(Contents.begin(), Contents.end(), AttributeItem::LessTag);
953 
954   ARMELFStreamer &Streamer = getStreamer();
955 
956   // Switch to .ARM.attributes section
957   if (AttributeSection) {
958     Streamer.SwitchSection(AttributeSection);
959   } else {
960     AttributeSection = Streamer.getContext().getELFSection(
961         ".ARM.attributes", ELF::SHT_ARM_ATTRIBUTES, 0);
962     Streamer.SwitchSection(AttributeSection);
963 
964     // Format version
965     Streamer.EmitIntValue(0x41, 1);
966   }
967 
968   // Vendor size + Vendor name + '\0'
969   const size_t VendorHeaderSize = 4 + CurrentVendor.size() + 1;
970 
971   // Tag + Tag Size
972   const size_t TagHeaderSize = 1 + 4;
973 
974   const size_t ContentsSize = calculateContentSize();
975 
976   Streamer.EmitIntValue(VendorHeaderSize + TagHeaderSize + ContentsSize, 4);
977   Streamer.EmitBytes(CurrentVendor);
978   Streamer.EmitIntValue(0, 1); // '\0'
979 
980   Streamer.EmitIntValue(ARMBuildAttrs::File, 1);
981   Streamer.EmitIntValue(TagHeaderSize + ContentsSize, 4);
982 
983   // Size should have been accounted for already, now
984   // emit each field as its type (ULEB or String)
985   for (size_t i = 0; i < Contents.size(); ++i) {
986     AttributeItem item = Contents[i];
987     Streamer.EmitULEB128IntValue(item.Tag);
988     switch (item.Type) {
989     default: llvm_unreachable("Invalid attribute type");
990     case AttributeItem::NumericAttribute:
991       Streamer.EmitULEB128IntValue(item.IntValue);
992       break;
993     case AttributeItem::TextAttribute:
994       Streamer.EmitBytes(item.StringValue);
995       Streamer.EmitIntValue(0, 1); // '\0'
996       break;
997     case AttributeItem::NumericAndTextAttributes:
998       Streamer.EmitULEB128IntValue(item.IntValue);
999       Streamer.EmitBytes(item.StringValue);
1000       Streamer.EmitIntValue(0, 1); // '\0'
1001       break;
1002     }
1003   }
1004 
1005   Contents.clear();
1006   FPU = ARM::FK_INVALID;
1007 }
1008 
1009 void ARMTargetELFStreamer::emitLabel(MCSymbol *Symbol) {
1010   ARMELFStreamer &Streamer = getStreamer();
1011   if (!Streamer.IsThumb)
1012     return;
1013 
1014   Streamer.getAssembler().registerSymbol(*Symbol);
1015   unsigned Type = cast<MCSymbolELF>(Symbol)->getType();
1016   if (Type == ELF::STT_FUNC || Type == ELF::STT_GNU_IFUNC)
1017     Streamer.EmitThumbFunc(Symbol);
1018 }
1019 
1020 void
1021 ARMTargetELFStreamer::AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *S) {
1022   getStreamer().EmitFixup(S, FK_Data_4);
1023 }
1024 
1025 void ARMTargetELFStreamer::emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) {
1026   if (const MCSymbolRefExpr *SRE = dyn_cast<MCSymbolRefExpr>(Value)) {
1027     const MCSymbol &Sym = SRE->getSymbol();
1028     if (!Sym.isDefined()) {
1029       getStreamer().EmitAssignment(Symbol, Value);
1030       return;
1031     }
1032   }
1033 
1034   getStreamer().EmitThumbFunc(Symbol);
1035   getStreamer().EmitAssignment(Symbol, Value);
1036 }
1037 
1038 void ARMTargetELFStreamer::emitInst(uint32_t Inst, char Suffix) {
1039   getStreamer().emitInst(Inst, Suffix);
1040 }
1041 
1042 void ARMELFStreamer::FinishImpl() {
1043   MCTargetStreamer &TS = *getTargetStreamer();
1044   ARMTargetStreamer &ATS = static_cast<ARMTargetStreamer &>(TS);
1045   ATS.finishAttributeSection();
1046 
1047   MCELFStreamer::FinishImpl();
1048 }
1049 
1050 inline void ARMELFStreamer::SwitchToEHSection(const char *Prefix,
1051                                               unsigned Type,
1052                                               unsigned Flags,
1053                                               SectionKind Kind,
1054                                               const MCSymbol &Fn) {
1055   const MCSectionELF &FnSection =
1056     static_cast<const MCSectionELF &>(Fn.getSection());
1057 
1058   // Create the name for new section
1059   StringRef FnSecName(FnSection.getSectionName());
1060   SmallString<128> EHSecName(Prefix);
1061   if (FnSecName != ".text") {
1062     EHSecName += FnSecName;
1063   }
1064 
1065   // Get .ARM.extab or .ARM.exidx section
1066   const MCSymbolELF *Group = FnSection.getGroup();
1067   if (Group)
1068     Flags |= ELF::SHF_GROUP;
1069   MCSectionELF *EHSection =
1070       getContext().getELFSection(EHSecName, Type, Flags, 0, Group,
1071                                  FnSection.getUniqueID(), nullptr, &FnSection);
1072 
1073   assert(EHSection && "Failed to get the required EH section");
1074 
1075   // Switch to .ARM.extab or .ARM.exidx section
1076   SwitchSection(EHSection);
1077   EmitCodeAlignment(4);
1078 }
1079 
1080 inline void ARMELFStreamer::SwitchToExTabSection(const MCSymbol &FnStart) {
1081   SwitchToEHSection(".ARM.extab", ELF::SHT_PROGBITS, ELF::SHF_ALLOC,
1082                     SectionKind::getData(), FnStart);
1083 }
1084 
1085 inline void ARMELFStreamer::SwitchToExIdxSection(const MCSymbol &FnStart) {
1086   SwitchToEHSection(".ARM.exidx", ELF::SHT_ARM_EXIDX,
1087                     ELF::SHF_ALLOC | ELF::SHF_LINK_ORDER,
1088                     SectionKind::getData(), FnStart);
1089 }
1090 void ARMELFStreamer::EmitFixup(const MCExpr *Expr, MCFixupKind Kind) {
1091   MCDataFragment *Frag = getOrCreateDataFragment();
1092   Frag->getFixups().push_back(MCFixup::create(Frag->getContents().size(), Expr,
1093                                               Kind));
1094 }
1095 
1096 void ARMELFStreamer::Reset() {
1097   ExTab = nullptr;
1098   FnStart = nullptr;
1099   Personality = nullptr;
1100   PersonalityIndex = ARM::EHABI::NUM_PERSONALITY_INDEX;
1101   FPReg = ARM::SP;
1102   FPOffset = 0;
1103   SPOffset = 0;
1104   PendingOffset = 0;
1105   UsedFP = false;
1106   CantUnwind = false;
1107 
1108   Opcodes.clear();
1109   UnwindOpAsm.Reset();
1110 }
1111 
1112 void ARMELFStreamer::emitFnStart() {
1113   assert(FnStart == nullptr);
1114   FnStart = getContext().createTempSymbol();
1115   EmitLabel(FnStart);
1116 }
1117 
1118 void ARMELFStreamer::emitFnEnd() {
1119   assert(FnStart && ".fnstart must precedes .fnend");
1120 
1121   // Emit unwind opcodes if there is no .handlerdata directive
1122   if (!ExTab && !CantUnwind)
1123     FlushUnwindOpcodes(true);
1124 
1125   // Emit the exception index table entry
1126   SwitchToExIdxSection(*FnStart);
1127 
1128   if (PersonalityIndex < ARM::EHABI::NUM_PERSONALITY_INDEX)
1129     EmitPersonalityFixup(GetAEABIUnwindPersonalityName(PersonalityIndex));
1130 
1131   const MCSymbolRefExpr *FnStartRef =
1132     MCSymbolRefExpr::create(FnStart,
1133                             MCSymbolRefExpr::VK_ARM_PREL31,
1134                             getContext());
1135 
1136   EmitValue(FnStartRef, 4);
1137 
1138   if (CantUnwind) {
1139     EmitIntValue(ARM::EHABI::EXIDX_CANTUNWIND, 4);
1140   } else if (ExTab) {
1141     // Emit a reference to the unwind opcodes in the ".ARM.extab" section.
1142     const MCSymbolRefExpr *ExTabEntryRef =
1143       MCSymbolRefExpr::create(ExTab,
1144                               MCSymbolRefExpr::VK_ARM_PREL31,
1145                               getContext());
1146     EmitValue(ExTabEntryRef, 4);
1147   } else {
1148     // For the __aeabi_unwind_cpp_pr0, we have to emit the unwind opcodes in
1149     // the second word of exception index table entry.  The size of the unwind
1150     // opcodes should always be 4 bytes.
1151     assert(PersonalityIndex == ARM::EHABI::AEABI_UNWIND_CPP_PR0 &&
1152            "Compact model must use __aeabi_unwind_cpp_pr0 as personality");
1153     assert(Opcodes.size() == 4u &&
1154            "Unwind opcode size for __aeabi_unwind_cpp_pr0 must be equal to 4");
1155     uint64_t Intval = Opcodes[0] |
1156                       Opcodes[1] << 8 |
1157                       Opcodes[2] << 16 |
1158                       Opcodes[3] << 24;
1159     EmitIntValue(Intval, Opcodes.size());
1160   }
1161 
1162   // Switch to the section containing FnStart
1163   SwitchSection(&FnStart->getSection());
1164 
1165   // Clean exception handling frame information
1166   Reset();
1167 }
1168 
1169 void ARMELFStreamer::emitCantUnwind() { CantUnwind = true; }
1170 
1171 // Add the R_ARM_NONE fixup at the same position
1172 void ARMELFStreamer::EmitPersonalityFixup(StringRef Name) {
1173   const MCSymbol *PersonalitySym = getContext().getOrCreateSymbol(Name);
1174 
1175   const MCSymbolRefExpr *PersonalityRef = MCSymbolRefExpr::create(
1176       PersonalitySym, MCSymbolRefExpr::VK_ARM_NONE, getContext());
1177 
1178   visitUsedExpr(*PersonalityRef);
1179   MCDataFragment *DF = getOrCreateDataFragment();
1180   DF->getFixups().push_back(MCFixup::create(DF->getContents().size(),
1181                                             PersonalityRef,
1182                                             MCFixup::getKindForSize(4, false)));
1183 }
1184 
1185 void ARMELFStreamer::FlushPendingOffset() {
1186   if (PendingOffset != 0) {
1187     UnwindOpAsm.EmitSPOffset(-PendingOffset);
1188     PendingOffset = 0;
1189   }
1190 }
1191 
1192 void ARMELFStreamer::FlushUnwindOpcodes(bool NoHandlerData) {
1193   // Emit the unwind opcode to restore $sp.
1194   if (UsedFP) {
1195     const MCRegisterInfo *MRI = getContext().getRegisterInfo();
1196     int64_t LastRegSaveSPOffset = SPOffset - PendingOffset;
1197     UnwindOpAsm.EmitSPOffset(LastRegSaveSPOffset - FPOffset);
1198     UnwindOpAsm.EmitSetSP(MRI->getEncodingValue(FPReg));
1199   } else {
1200     FlushPendingOffset();
1201   }
1202 
1203   // Finalize the unwind opcode sequence
1204   UnwindOpAsm.Finalize(PersonalityIndex, Opcodes);
1205 
1206   // For compact model 0, we have to emit the unwind opcodes in the .ARM.exidx
1207   // section.  Thus, we don't have to create an entry in the .ARM.extab
1208   // section.
1209   if (NoHandlerData && PersonalityIndex == ARM::EHABI::AEABI_UNWIND_CPP_PR0)
1210     return;
1211 
1212   // Switch to .ARM.extab section.
1213   SwitchToExTabSection(*FnStart);
1214 
1215   // Create .ARM.extab label for offset in .ARM.exidx
1216   assert(!ExTab);
1217   ExTab = getContext().createTempSymbol();
1218   EmitLabel(ExTab);
1219 
1220   // Emit personality
1221   if (Personality) {
1222     const MCSymbolRefExpr *PersonalityRef =
1223       MCSymbolRefExpr::create(Personality,
1224                               MCSymbolRefExpr::VK_ARM_PREL31,
1225                               getContext());
1226 
1227     EmitValue(PersonalityRef, 4);
1228   }
1229 
1230   // Emit unwind opcodes
1231   assert((Opcodes.size() % 4) == 0 &&
1232          "Unwind opcode size for __aeabi_cpp_unwind_pr0 must be multiple of 4");
1233   for (unsigned I = 0; I != Opcodes.size(); I += 4) {
1234     uint64_t Intval = Opcodes[I] |
1235                       Opcodes[I + 1] << 8 |
1236                       Opcodes[I + 2] << 16 |
1237                       Opcodes[I + 3] << 24;
1238     EmitIntValue(Intval, 4);
1239   }
1240 
1241   // According to ARM EHABI section 9.2, if the __aeabi_unwind_cpp_pr1() or
1242   // __aeabi_unwind_cpp_pr2() is used, then the handler data must be emitted
1243   // after the unwind opcodes.  The handler data consists of several 32-bit
1244   // words, and should be terminated by zero.
1245   //
1246   // In case that the .handlerdata directive is not specified by the
1247   // programmer, we should emit zero to terminate the handler data.
1248   if (NoHandlerData && !Personality)
1249     EmitIntValue(0, 4);
1250 }
1251 
1252 void ARMELFStreamer::emitHandlerData() { FlushUnwindOpcodes(false); }
1253 
1254 void ARMELFStreamer::emitPersonality(const MCSymbol *Per) {
1255   Personality = Per;
1256   UnwindOpAsm.setPersonality(Per);
1257 }
1258 
1259 void ARMELFStreamer::emitPersonalityIndex(unsigned Index) {
1260   assert(Index < ARM::EHABI::NUM_PERSONALITY_INDEX && "invalid index");
1261   PersonalityIndex = Index;
1262 }
1263 
1264 void ARMELFStreamer::emitSetFP(unsigned NewFPReg, unsigned NewSPReg,
1265                                int64_t Offset) {
1266   assert((NewSPReg == ARM::SP || NewSPReg == FPReg) &&
1267          "the operand of .setfp directive should be either $sp or $fp");
1268 
1269   UsedFP = true;
1270   FPReg = NewFPReg;
1271 
1272   if (NewSPReg == ARM::SP)
1273     FPOffset = SPOffset + Offset;
1274   else
1275     FPOffset += Offset;
1276 }
1277 
1278 void ARMELFStreamer::emitMovSP(unsigned Reg, int64_t Offset) {
1279   assert((Reg != ARM::SP && Reg != ARM::PC) &&
1280          "the operand of .movsp cannot be either sp or pc");
1281   assert(FPReg == ARM::SP && "current FP must be SP");
1282 
1283   FlushPendingOffset();
1284 
1285   FPReg = Reg;
1286   FPOffset = SPOffset + Offset;
1287 
1288   const MCRegisterInfo *MRI = getContext().getRegisterInfo();
1289   UnwindOpAsm.EmitSetSP(MRI->getEncodingValue(FPReg));
1290 }
1291 
1292 void ARMELFStreamer::emitPad(int64_t Offset) {
1293   // Track the change of the $sp offset
1294   SPOffset -= Offset;
1295 
1296   // To squash multiple .pad directives, we should delay the unwind opcode
1297   // until the .save, .vsave, .handlerdata, or .fnend directives.
1298   PendingOffset -= Offset;
1299 }
1300 
1301 void ARMELFStreamer::emitRegSave(const SmallVectorImpl<unsigned> &RegList,
1302                                  bool IsVector) {
1303   // Collect the registers in the register list
1304   unsigned Count = 0;
1305   uint32_t Mask = 0;
1306   const MCRegisterInfo *MRI = getContext().getRegisterInfo();
1307   for (size_t i = 0; i < RegList.size(); ++i) {
1308     unsigned Reg = MRI->getEncodingValue(RegList[i]);
1309     assert(Reg < (IsVector ? 32U : 16U) && "Register out of range");
1310     unsigned Bit = (1u << Reg);
1311     if ((Mask & Bit) == 0) {
1312       Mask |= Bit;
1313       ++Count;
1314     }
1315   }
1316 
1317   // Track the change the $sp offset: For the .save directive, the
1318   // corresponding push instruction will decrease the $sp by (4 * Count).
1319   // For the .vsave directive, the corresponding vpush instruction will
1320   // decrease $sp by (8 * Count).
1321   SPOffset -= Count * (IsVector ? 8 : 4);
1322 
1323   // Emit the opcode
1324   FlushPendingOffset();
1325   if (IsVector)
1326     UnwindOpAsm.EmitVFPRegSave(Mask);
1327   else
1328     UnwindOpAsm.EmitRegSave(Mask);
1329 }
1330 
1331 void ARMELFStreamer::emitUnwindRaw(int64_t Offset,
1332                                    const SmallVectorImpl<uint8_t> &Opcodes) {
1333   FlushPendingOffset();
1334   SPOffset = SPOffset - Offset;
1335   UnwindOpAsm.EmitRaw(Opcodes);
1336 }
1337 
1338 namespace llvm {
1339 
1340 MCTargetStreamer *createARMTargetAsmStreamer(MCStreamer &S,
1341                                              formatted_raw_ostream &OS,
1342                                              MCInstPrinter *InstPrint,
1343                                              bool isVerboseAsm) {
1344   return new ARMTargetAsmStreamer(S, OS, *InstPrint, isVerboseAsm);
1345 }
1346 
1347 MCTargetStreamer *createARMNullTargetStreamer(MCStreamer &S) {
1348   return new ARMTargetStreamer(S);
1349 }
1350 
1351 MCTargetStreamer *createARMObjectTargetStreamer(MCStreamer &S,
1352                                                 const MCSubtargetInfo &STI) {
1353   const Triple &TT = STI.getTargetTriple();
1354   if (TT.isOSBinFormatELF())
1355     return new ARMTargetELFStreamer(S);
1356   return new ARMTargetStreamer(S);
1357 }
1358 
1359 MCELFStreamer *createARMELFStreamer(MCContext &Context, MCAsmBackend &TAB,
1360                                     raw_pwrite_stream &OS,
1361                                     MCCodeEmitter *Emitter, bool RelaxAll,
1362                                     bool IsThumb) {
1363     ARMELFStreamer *S = new ARMELFStreamer(Context, TAB, OS, Emitter, IsThumb);
1364     // FIXME: This should eventually end up somewhere else where more
1365     // intelligent flag decisions can be made. For now we are just maintaining
1366     // the status quo for ARM and setting EF_ARM_EABI_VER5 as the default.
1367     S->getAssembler().setELFHeaderEFlags(ELF::EF_ARM_EABI_VER5);
1368 
1369     if (RelaxAll)
1370       S->getAssembler().setRelaxAll(true);
1371     return S;
1372   }
1373 
1374 }
1375 
1376 
1377