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 "ARMArchName.h"
17 #include "ARMFPUName.h"
18 #include "ARMRegisterInfo.h"
19 #include "ARMUnwindOpAsm.h"
20 #include "llvm/ADT/StringExtras.h"
21 #include "llvm/ADT/Twine.h"
22 #include "llvm/MC/MCAsmBackend.h"
23 #include "llvm/MC/MCAsmInfo.h"
24 #include "llvm/MC/MCAssembler.h"
25 #include "llvm/MC/MCCodeEmitter.h"
26 #include "llvm/MC/MCContext.h"
27 #include "llvm/MC/MCELF.h"
28 #include "llvm/MC/MCELFStreamer.h"
29 #include "llvm/MC/MCELFSymbolFlags.h"
30 #include "llvm/MC/MCExpr.h"
31 #include "llvm/MC/MCInst.h"
32 #include "llvm/MC/MCInstPrinter.h"
33 #include "llvm/MC/MCObjectFileInfo.h"
34 #include "llvm/MC/MCObjectStreamer.h"
35 #include "llvm/MC/MCRegisterInfo.h"
36 #include "llvm/MC/MCSection.h"
37 #include "llvm/MC/MCSectionELF.h"
38 #include "llvm/MC/MCStreamer.h"
39 #include "llvm/MC/MCSymbol.h"
40 #include "llvm/MC/MCValue.h"
41 #include "llvm/Support/ARMBuildAttributes.h"
42 #include "llvm/Support/ARMEHABI.h"
43 #include "llvm/Support/Debug.h"
44 #include "llvm/Support/ELF.h"
45 #include "llvm/Support/FormattedStream.h"
46 #include "llvm/Support/LEB128.h"
47 #include "llvm/Support/raw_ostream.h"
48 #include <algorithm>
49 
50 using namespace llvm;
51 
52 static std::string GetAEABIUnwindPersonalityName(unsigned Index) {
53   assert(Index < ARM::EHABI::NUM_PERSONALITY_INDEX &&
54          "Invalid personality index");
55   return (Twine("__aeabi_unwind_cpp_pr") + Twine(Index)).str();
56 }
57 
58 static const char *GetFPUName(unsigned ID) {
59   switch (ID) {
60   default:
61     llvm_unreachable("Unknown FPU kind");
62     break;
63 #define ARM_FPU_NAME(NAME, ID) case ARM::ID: return NAME;
64 #include "ARMFPUName.def"
65   }
66   return nullptr;
67 }
68 
69 static const char *GetArchName(unsigned ID) {
70   switch (ID) {
71   default:
72     llvm_unreachable("Unknown ARCH kind");
73     break;
74 #define ARM_ARCH_NAME(NAME, ID, DEFAULT_CPU_NAME, DEFAULT_CPU_ARCH) \
75   case ARM::ID: return NAME;
76 #define ARM_ARCH_ALIAS(NAME, ID) /* empty */
77 #include "ARMArchName.def"
78   }
79   return nullptr;
80 }
81 
82 static const char *GetArchDefaultCPUName(unsigned ID) {
83   switch (ID) {
84   default:
85     llvm_unreachable("Unknown ARCH kind");
86     break;
87 #define ARM_ARCH_NAME(NAME, ID, DEFAULT_CPU_NAME, DEFAULT_CPU_ARCH) \
88   case ARM::ID: return DEFAULT_CPU_NAME;
89 #define ARM_ARCH_ALIAS(NAME, ID) /* empty */
90 #include "ARMArchName.def"
91   }
92   return nullptr;
93 }
94 
95 static unsigned GetArchDefaultCPUArch(unsigned ID) {
96   switch (ID) {
97   default:
98     llvm_unreachable("Unknown ARCH kind");
99     break;
100 #define ARM_ARCH_NAME(NAME, ID, DEFAULT_CPU_NAME, DEFAULT_CPU_ARCH) \
101   case ARM::ID: return ARMBuildAttrs::DEFAULT_CPU_ARCH;
102 #define ARM_ARCH_ALIAS(NAME, ID) /* empty */
103 #include "ARMArchName.def"
104   }
105   return 0;
106 }
107 
108 namespace {
109 
110 class ARMELFStreamer;
111 
112 class ARMTargetAsmStreamer : public ARMTargetStreamer {
113   formatted_raw_ostream &OS;
114   MCInstPrinter &InstPrinter;
115   bool IsVerboseAsm;
116 
117   void emitFnStart() override;
118   void emitFnEnd() override;
119   void emitCantUnwind() override;
120   void emitPersonality(const MCSymbol *Personality) override;
121   void emitPersonalityIndex(unsigned Index) override;
122   void emitHandlerData() override;
123   void emitSetFP(unsigned FpReg, unsigned SpReg, int64_t Offset = 0) override;
124   void emitMovSP(unsigned Reg, int64_t Offset = 0) override;
125   void emitPad(int64_t Offset) override;
126   void emitRegSave(const SmallVectorImpl<unsigned> &RegList,
127                    bool isVector) override;
128   void emitUnwindRaw(int64_t Offset,
129                      const SmallVectorImpl<uint8_t> &Opcodes) override;
130 
131   void switchVendor(StringRef Vendor) override;
132   void emitAttribute(unsigned Attribute, unsigned Value) override;
133   void emitTextAttribute(unsigned Attribute, StringRef String) override;
134   void emitIntTextAttribute(unsigned Attribute, unsigned IntValue,
135                             StringRef StrinValue) override;
136   void emitArch(unsigned Arch) override;
137   void emitObjectArch(unsigned Arch) override;
138   void emitFPU(unsigned FPU) override;
139   void emitInst(uint32_t Inst, char Suffix = '\0') override;
140   void finishAttributeSection() override;
141 
142   void AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *SRE) override;
143   void emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) override;
144 
145 public:
146   ARMTargetAsmStreamer(MCStreamer &S, formatted_raw_ostream &OS,
147                        MCInstPrinter &InstPrinter, bool VerboseAsm);
148 };
149 
150 ARMTargetAsmStreamer::ARMTargetAsmStreamer(MCStreamer &S,
151                                            formatted_raw_ostream &OS,
152                                            MCInstPrinter &InstPrinter,
153                                            bool VerboseAsm)
154     : ARMTargetStreamer(S), OS(OS), InstPrinter(InstPrinter),
155       IsVerboseAsm(VerboseAsm) {}
156 void ARMTargetAsmStreamer::emitFnStart() { OS << "\t.fnstart\n"; }
157 void ARMTargetAsmStreamer::emitFnEnd() { OS << "\t.fnend\n"; }
158 void ARMTargetAsmStreamer::emitCantUnwind() { OS << "\t.cantunwind\n"; }
159 void ARMTargetAsmStreamer::emitPersonality(const MCSymbol *Personality) {
160   OS << "\t.personality " << Personality->getName() << '\n';
161 }
162 void ARMTargetAsmStreamer::emitPersonalityIndex(unsigned Index) {
163   OS << "\t.personalityindex " << Index << '\n';
164 }
165 void ARMTargetAsmStreamer::emitHandlerData() { OS << "\t.handlerdata\n"; }
166 void ARMTargetAsmStreamer::emitSetFP(unsigned FpReg, unsigned SpReg,
167                                      int64_t Offset) {
168   OS << "\t.setfp\t";
169   InstPrinter.printRegName(OS, FpReg);
170   OS << ", ";
171   InstPrinter.printRegName(OS, SpReg);
172   if (Offset)
173     OS << ", #" << Offset;
174   OS << '\n';
175 }
176 void ARMTargetAsmStreamer::emitMovSP(unsigned Reg, int64_t Offset) {
177   assert((Reg != ARM::SP && Reg != ARM::PC) &&
178          "the operand of .movsp cannot be either sp or pc");
179 
180   OS << "\t.movsp\t";
181   InstPrinter.printRegName(OS, Reg);
182   if (Offset)
183     OS << ", #" << Offset;
184   OS << '\n';
185 }
186 void ARMTargetAsmStreamer::emitPad(int64_t Offset) {
187   OS << "\t.pad\t#" << Offset << '\n';
188 }
189 void ARMTargetAsmStreamer::emitRegSave(const SmallVectorImpl<unsigned> &RegList,
190                                        bool isVector) {
191   assert(RegList.size() && "RegList should not be empty");
192   if (isVector)
193     OS << "\t.vsave\t{";
194   else
195     OS << "\t.save\t{";
196 
197   InstPrinter.printRegName(OS, RegList[0]);
198 
199   for (unsigned i = 1, e = RegList.size(); i != e; ++i) {
200     OS << ", ";
201     InstPrinter.printRegName(OS, RegList[i]);
202   }
203 
204   OS << "}\n";
205 }
206 void ARMTargetAsmStreamer::switchVendor(StringRef Vendor) {
207 }
208 void ARMTargetAsmStreamer::emitAttribute(unsigned Attribute, unsigned Value) {
209   OS << "\t.eabi_attribute\t" << Attribute << ", " << Twine(Value);
210   if (IsVerboseAsm) {
211     StringRef Name = ARMBuildAttrs::AttrTypeAsString(Attribute);
212     if (!Name.empty())
213       OS << "\t@ " << Name;
214   }
215   OS << "\n";
216 }
217 void ARMTargetAsmStreamer::emitTextAttribute(unsigned Attribute,
218                                              StringRef String) {
219   switch (Attribute) {
220   case ARMBuildAttrs::CPU_name:
221     OS << "\t.cpu\t" << String.lower();
222     break;
223   default:
224     OS << "\t.eabi_attribute\t" << Attribute << ", \"" << String << "\"";
225     if (IsVerboseAsm) {
226       StringRef Name = ARMBuildAttrs::AttrTypeAsString(Attribute);
227       if (!Name.empty())
228         OS << "\t@ " << Name;
229     }
230     break;
231   }
232   OS << "\n";
233 }
234 void ARMTargetAsmStreamer::emitIntTextAttribute(unsigned Attribute,
235                                                 unsigned IntValue,
236                                                 StringRef StringValue) {
237   switch (Attribute) {
238   default: llvm_unreachable("unsupported multi-value attribute in asm mode");
239   case ARMBuildAttrs::compatibility:
240     OS << "\t.eabi_attribute\t" << Attribute << ", " << IntValue;
241     if (!StringValue.empty())
242       OS << ", \"" << StringValue << "\"";
243     if (IsVerboseAsm)
244       OS << "\t@ " << ARMBuildAttrs::AttrTypeAsString(Attribute);
245     break;
246   }
247   OS << "\n";
248 }
249 void ARMTargetAsmStreamer::emitArch(unsigned Arch) {
250   OS << "\t.arch\t" << GetArchName(Arch) << "\n";
251 }
252 void ARMTargetAsmStreamer::emitObjectArch(unsigned Arch) {
253   OS << "\t.object_arch\t" << GetArchName(Arch) << '\n';
254 }
255 void ARMTargetAsmStreamer::emitFPU(unsigned FPU) {
256   OS << "\t.fpu\t" << GetFPUName(FPU) << "\n";
257 }
258 void ARMTargetAsmStreamer::finishAttributeSection() {
259 }
260 void
261 ARMTargetAsmStreamer::AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *S) {
262   OS << "\t.tlsdescseq\t" << S->getSymbol().getName();
263 }
264 
265 void ARMTargetAsmStreamer::emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) {
266   OS << "\t.thumb_set\t" << *Symbol << ", " << *Value << '\n';
267 }
268 
269 void ARMTargetAsmStreamer::emitInst(uint32_t Inst, char Suffix) {
270   OS << "\t.inst";
271   if (Suffix)
272     OS << "." << Suffix;
273   OS << "\t0x" << utohexstr(Inst) << "\n";
274 }
275 
276 void ARMTargetAsmStreamer::emitUnwindRaw(int64_t Offset,
277                                       const SmallVectorImpl<uint8_t> &Opcodes) {
278   OS << "\t.unwind_raw " << Offset;
279   for (SmallVectorImpl<uint8_t>::const_iterator OCI = Opcodes.begin(),
280                                                 OCE = Opcodes.end();
281        OCI != OCE; ++OCI)
282     OS << ", 0x" << utohexstr(*OCI);
283   OS << '\n';
284 }
285 
286 class ARMTargetELFStreamer : public ARMTargetStreamer {
287 private:
288   // This structure holds all attributes, accounting for
289   // their string/numeric value, so we can later emmit them
290   // in declaration order, keeping all in the same vector
291   struct AttributeItem {
292     enum {
293       HiddenAttribute = 0,
294       NumericAttribute,
295       TextAttribute,
296       NumericAndTextAttributes
297     } Type;
298     unsigned Tag;
299     unsigned IntValue;
300     StringRef StringValue;
301 
302     static bool LessTag(const AttributeItem &LHS, const AttributeItem &RHS) {
303       return (LHS.Tag < RHS.Tag);
304     }
305   };
306 
307   StringRef CurrentVendor;
308   unsigned FPU;
309   unsigned Arch;
310   unsigned EmittedArch;
311   SmallVector<AttributeItem, 64> Contents;
312 
313   const MCSection *AttributeSection;
314 
315   AttributeItem *getAttributeItem(unsigned Attribute) {
316     for (size_t i = 0; i < Contents.size(); ++i)
317       if (Contents[i].Tag == Attribute)
318         return &Contents[i];
319     return nullptr;
320   }
321 
322   void setAttributeItem(unsigned Attribute, unsigned Value,
323                         bool OverwriteExisting) {
324     // Look for existing attribute item
325     if (AttributeItem *Item = getAttributeItem(Attribute)) {
326       if (!OverwriteExisting)
327         return;
328       Item->Type = AttributeItem::NumericAttribute;
329       Item->IntValue = Value;
330       return;
331     }
332 
333     // Create new attribute item
334     AttributeItem Item = {
335       AttributeItem::NumericAttribute,
336       Attribute,
337       Value,
338       StringRef("")
339     };
340     Contents.push_back(Item);
341   }
342 
343   void setAttributeItem(unsigned Attribute, StringRef Value,
344                         bool OverwriteExisting) {
345     // Look for existing attribute item
346     if (AttributeItem *Item = getAttributeItem(Attribute)) {
347       if (!OverwriteExisting)
348         return;
349       Item->Type = AttributeItem::TextAttribute;
350       Item->StringValue = Value;
351       return;
352     }
353 
354     // Create new attribute item
355     AttributeItem Item = {
356       AttributeItem::TextAttribute,
357       Attribute,
358       0,
359       Value
360     };
361     Contents.push_back(Item);
362   }
363 
364   void setAttributeItems(unsigned Attribute, unsigned IntValue,
365                          StringRef StringValue, bool OverwriteExisting) {
366     // Look for existing attribute item
367     if (AttributeItem *Item = getAttributeItem(Attribute)) {
368       if (!OverwriteExisting)
369         return;
370       Item->Type = AttributeItem::NumericAndTextAttributes;
371       Item->IntValue = IntValue;
372       Item->StringValue = StringValue;
373       return;
374     }
375 
376     // Create new attribute item
377     AttributeItem Item = {
378       AttributeItem::NumericAndTextAttributes,
379       Attribute,
380       IntValue,
381       StringValue
382     };
383     Contents.push_back(Item);
384   }
385 
386   void emitArchDefaultAttributes();
387   void emitFPUDefaultAttributes();
388 
389   ARMELFStreamer &getStreamer();
390 
391   void emitFnStart() override;
392   void emitFnEnd() override;
393   void emitCantUnwind() override;
394   void emitPersonality(const MCSymbol *Personality) override;
395   void emitPersonalityIndex(unsigned Index) override;
396   void emitHandlerData() override;
397   void emitSetFP(unsigned FpReg, unsigned SpReg, int64_t Offset = 0) override;
398   void emitMovSP(unsigned Reg, int64_t Offset = 0) override;
399   void emitPad(int64_t Offset) override;
400   void emitRegSave(const SmallVectorImpl<unsigned> &RegList,
401                    bool isVector) override;
402   void emitUnwindRaw(int64_t Offset,
403                      const SmallVectorImpl<uint8_t> &Opcodes) override;
404 
405   void switchVendor(StringRef Vendor) override;
406   void emitAttribute(unsigned Attribute, unsigned Value) override;
407   void emitTextAttribute(unsigned Attribute, StringRef String) override;
408   void emitIntTextAttribute(unsigned Attribute, unsigned IntValue,
409                             StringRef StringValue) override;
410   void emitArch(unsigned Arch) override;
411   void emitObjectArch(unsigned Arch) override;
412   void emitFPU(unsigned FPU) override;
413   void emitInst(uint32_t Inst, char Suffix = '\0') override;
414   void finishAttributeSection() override;
415   void emitLabel(MCSymbol *Symbol) override;
416 
417   void AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *SRE) override;
418   void emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) override;
419 
420   size_t calculateContentSize() const;
421 
422 public:
423   ARMTargetELFStreamer(MCStreamer &S)
424     : ARMTargetStreamer(S), CurrentVendor("aeabi"), FPU(ARM::INVALID_FPU),
425       Arch(ARM::INVALID_ARCH), EmittedArch(ARM::INVALID_ARCH),
426       AttributeSection(nullptr) {}
427 };
428 
429 /// Extend the generic ELFStreamer class so that it can emit mapping symbols at
430 /// the appropriate points in the object files. These symbols are defined in the
431 /// ARM ELF ABI: infocenter.arm.com/help/topic/com.arm.../IHI0044D_aaelf.pdf.
432 ///
433 /// In brief: $a, $t or $d should be emitted at the start of each contiguous
434 /// region of ARM code, Thumb code or data in a section. In practice, this
435 /// emission does not rely on explicit assembler directives but on inherent
436 /// properties of the directives doing the emission (e.g. ".byte" is data, "add
437 /// r0, r0, r0" an instruction).
438 ///
439 /// As a result this system is orthogonal to the DataRegion infrastructure used
440 /// by MachO. Beware!
441 class ARMELFStreamer : public MCELFStreamer {
442 public:
443   friend class ARMTargetELFStreamer;
444 
445   ARMELFStreamer(MCContext &Context, MCAsmBackend &TAB, raw_ostream &OS,
446                  MCCodeEmitter *Emitter, bool IsThumb)
447       : MCELFStreamer(Context, TAB, OS, Emitter), IsThumb(IsThumb),
448         MappingSymbolCounter(0), LastEMS(EMS_None) {
449     Reset();
450   }
451 
452   ~ARMELFStreamer() {}
453 
454   void FinishImpl() override;
455 
456   // ARM exception handling directives
457   void emitFnStart();
458   void emitFnEnd();
459   void emitCantUnwind();
460   void emitPersonality(const MCSymbol *Per);
461   void emitPersonalityIndex(unsigned index);
462   void emitHandlerData();
463   void emitSetFP(unsigned NewFpReg, unsigned NewSpReg, int64_t Offset = 0);
464   void emitMovSP(unsigned Reg, int64_t Offset = 0);
465   void emitPad(int64_t Offset);
466   void emitRegSave(const SmallVectorImpl<unsigned> &RegList, bool isVector);
467   void emitUnwindRaw(int64_t Offset, const SmallVectorImpl<uint8_t> &Opcodes);
468 
469   void ChangeSection(const MCSection *Section,
470                      const MCExpr *Subsection) override {
471     // We have to keep track of the mapping symbol state of any sections we
472     // use. Each one should start off as EMS_None, which is provided as the
473     // default constructor by DenseMap::lookup.
474     LastMappingSymbols[getPreviousSection().first] = LastEMS;
475     LastEMS = LastMappingSymbols.lookup(Section);
476 
477     MCELFStreamer::ChangeSection(Section, Subsection);
478   }
479 
480   /// This function is the one used to emit instruction data into the ELF
481   /// streamer. We override it to add the appropriate mapping symbol if
482   /// necessary.
483   void EmitInstruction(const MCInst& Inst,
484                        const MCSubtargetInfo &STI) override {
485     if (IsThumb)
486       EmitThumbMappingSymbol();
487     else
488       EmitARMMappingSymbol();
489 
490     MCELFStreamer::EmitInstruction(Inst, STI);
491   }
492 
493   void emitInst(uint32_t Inst, char Suffix) {
494     unsigned Size;
495     char Buffer[4];
496     const bool LittleEndian = getContext().getAsmInfo()->isLittleEndian();
497 
498     switch (Suffix) {
499     case '\0':
500       Size = 4;
501 
502       assert(!IsThumb);
503       EmitARMMappingSymbol();
504       for (unsigned II = 0, IE = Size; II != IE; II++) {
505         const unsigned I = LittleEndian ? (Size - II - 1) : II;
506         Buffer[Size - II - 1] = uint8_t(Inst >> I * CHAR_BIT);
507       }
508 
509       break;
510     case 'n':
511     case 'w':
512       Size = (Suffix == 'n' ? 2 : 4);
513 
514       assert(IsThumb);
515       EmitThumbMappingSymbol();
516       for (unsigned II = 0, IE = Size; II != IE; II = II + 2) {
517         const unsigned I0 = LittleEndian ? II + 0 : (Size - II - 1);
518         const unsigned I1 = LittleEndian ? II + 1 : (Size - II - 2);
519         Buffer[Size - II - 2] = uint8_t(Inst >> I0 * CHAR_BIT);
520         Buffer[Size - II - 1] = uint8_t(Inst >> I1 * CHAR_BIT);
521       }
522 
523       break;
524     default:
525       llvm_unreachable("Invalid Suffix");
526     }
527 
528     MCELFStreamer::EmitBytes(StringRef(Buffer, Size));
529   }
530 
531   /// This is one of the functions used to emit data into an ELF section, so the
532   /// ARM streamer overrides it to add the appropriate mapping symbol ($d) if
533   /// necessary.
534   void EmitBytes(StringRef Data) override {
535     EmitDataMappingSymbol();
536     MCELFStreamer::EmitBytes(Data);
537   }
538 
539   /// This is one of the functions used to emit data into an ELF section, so the
540   /// ARM streamer overrides it to add the appropriate mapping symbol ($d) if
541   /// necessary.
542   void EmitValueImpl(const MCExpr *Value, unsigned Size,
543                      const SMLoc &Loc) override {
544     EmitDataMappingSymbol();
545     MCELFStreamer::EmitValueImpl(Value, Size);
546   }
547 
548   void EmitAssemblerFlag(MCAssemblerFlag Flag) override {
549     MCELFStreamer::EmitAssemblerFlag(Flag);
550 
551     switch (Flag) {
552     case MCAF_SyntaxUnified:
553       return; // no-op here.
554     case MCAF_Code16:
555       IsThumb = true;
556       return; // Change to Thumb mode
557     case MCAF_Code32:
558       IsThumb = false;
559       return; // Change to ARM mode
560     case MCAF_Code64:
561       return;
562     case MCAF_SubsectionsViaSymbols:
563       return;
564     }
565   }
566 
567 private:
568   enum ElfMappingSymbol {
569     EMS_None,
570     EMS_ARM,
571     EMS_Thumb,
572     EMS_Data
573   };
574 
575   void EmitDataMappingSymbol() {
576     if (LastEMS == EMS_Data) return;
577     EmitMappingSymbol("$d");
578     LastEMS = EMS_Data;
579   }
580 
581   void EmitThumbMappingSymbol() {
582     if (LastEMS == EMS_Thumb) return;
583     EmitMappingSymbol("$t");
584     LastEMS = EMS_Thumb;
585   }
586 
587   void EmitARMMappingSymbol() {
588     if (LastEMS == EMS_ARM) return;
589     EmitMappingSymbol("$a");
590     LastEMS = EMS_ARM;
591   }
592 
593   void EmitMappingSymbol(StringRef Name) {
594     MCSymbol *Start = getContext().CreateTempSymbol();
595     EmitLabel(Start);
596 
597     MCSymbol *Symbol =
598       getContext().GetOrCreateSymbol(Name + "." +
599                                      Twine(MappingSymbolCounter++));
600 
601     MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
602     MCELF::SetType(SD, ELF::STT_NOTYPE);
603     MCELF::SetBinding(SD, ELF::STB_LOCAL);
604     SD.setExternal(false);
605     AssignSection(Symbol, getCurrentSection().first);
606 
607     const MCExpr *Value = MCSymbolRefExpr::Create(Start, getContext());
608     Symbol->setVariableValue(Value);
609   }
610 
611   void EmitThumbFunc(MCSymbol *Func) override {
612     getAssembler().setIsThumbFunc(Func);
613     EmitSymbolAttribute(Func, MCSA_ELF_TypeFunction);
614   }
615 
616   // Helper functions for ARM exception handling directives
617   void Reset();
618 
619   void EmitPersonalityFixup(StringRef Name);
620   void FlushPendingOffset();
621   void FlushUnwindOpcodes(bool NoHandlerData);
622 
623   void SwitchToEHSection(const char *Prefix, unsigned Type, unsigned Flags,
624                          SectionKind Kind, const MCSymbol &Fn);
625   void SwitchToExTabSection(const MCSymbol &FnStart);
626   void SwitchToExIdxSection(const MCSymbol &FnStart);
627 
628   void EmitFixup(const MCExpr *Expr, MCFixupKind Kind);
629 
630   bool IsThumb;
631   int64_t MappingSymbolCounter;
632 
633   DenseMap<const MCSection *, ElfMappingSymbol> LastMappingSymbols;
634   ElfMappingSymbol LastEMS;
635 
636   // ARM Exception Handling Frame Information
637   MCSymbol *ExTab;
638   MCSymbol *FnStart;
639   const MCSymbol *Personality;
640   unsigned PersonalityIndex;
641   unsigned FPReg; // Frame pointer register
642   int64_t FPOffset; // Offset: (final frame pointer) - (initial $sp)
643   int64_t SPOffset; // Offset: (final $sp) - (initial $sp)
644   int64_t PendingOffset; // Offset: (final $sp) - (emitted $sp)
645   bool UsedFP;
646   bool CantUnwind;
647   SmallVector<uint8_t, 64> Opcodes;
648   UnwindOpcodeAssembler UnwindOpAsm;
649 };
650 } // end anonymous namespace
651 
652 ARMELFStreamer &ARMTargetELFStreamer::getStreamer() {
653   return static_cast<ARMELFStreamer &>(Streamer);
654 }
655 
656 void ARMTargetELFStreamer::emitFnStart() { getStreamer().emitFnStart(); }
657 void ARMTargetELFStreamer::emitFnEnd() { getStreamer().emitFnEnd(); }
658 void ARMTargetELFStreamer::emitCantUnwind() { getStreamer().emitCantUnwind(); }
659 void ARMTargetELFStreamer::emitPersonality(const MCSymbol *Personality) {
660   getStreamer().emitPersonality(Personality);
661 }
662 void ARMTargetELFStreamer::emitPersonalityIndex(unsigned Index) {
663   getStreamer().emitPersonalityIndex(Index);
664 }
665 void ARMTargetELFStreamer::emitHandlerData() {
666   getStreamer().emitHandlerData();
667 }
668 void ARMTargetELFStreamer::emitSetFP(unsigned FpReg, unsigned SpReg,
669                                      int64_t Offset) {
670   getStreamer().emitSetFP(FpReg, SpReg, Offset);
671 }
672 void ARMTargetELFStreamer::emitMovSP(unsigned Reg, int64_t Offset) {
673   getStreamer().emitMovSP(Reg, Offset);
674 }
675 void ARMTargetELFStreamer::emitPad(int64_t Offset) {
676   getStreamer().emitPad(Offset);
677 }
678 void ARMTargetELFStreamer::emitRegSave(const SmallVectorImpl<unsigned> &RegList,
679                                        bool isVector) {
680   getStreamer().emitRegSave(RegList, isVector);
681 }
682 void ARMTargetELFStreamer::emitUnwindRaw(int64_t Offset,
683                                       const SmallVectorImpl<uint8_t> &Opcodes) {
684   getStreamer().emitUnwindRaw(Offset, Opcodes);
685 }
686 void ARMTargetELFStreamer::switchVendor(StringRef Vendor) {
687   assert(!Vendor.empty() && "Vendor cannot be empty.");
688 
689   if (CurrentVendor == Vendor)
690     return;
691 
692   if (!CurrentVendor.empty())
693     finishAttributeSection();
694 
695   assert(Contents.empty() &&
696          ".ARM.attributes should be flushed before changing vendor");
697   CurrentVendor = Vendor;
698 
699 }
700 void ARMTargetELFStreamer::emitAttribute(unsigned Attribute, unsigned Value) {
701   setAttributeItem(Attribute, Value, /* OverwriteExisting= */ true);
702 }
703 void ARMTargetELFStreamer::emitTextAttribute(unsigned Attribute,
704                                              StringRef Value) {
705   setAttributeItem(Attribute, Value, /* OverwriteExisting= */ true);
706 }
707 void ARMTargetELFStreamer::emitIntTextAttribute(unsigned Attribute,
708                                                 unsigned IntValue,
709                                                 StringRef StringValue) {
710   setAttributeItems(Attribute, IntValue, StringValue,
711                     /* OverwriteExisting= */ true);
712 }
713 void ARMTargetELFStreamer::emitArch(unsigned Value) {
714   Arch = Value;
715 }
716 void ARMTargetELFStreamer::emitObjectArch(unsigned Value) {
717   EmittedArch = Value;
718 }
719 void ARMTargetELFStreamer::emitArchDefaultAttributes() {
720   using namespace ARMBuildAttrs;
721 
722   setAttributeItem(CPU_name, GetArchDefaultCPUName(Arch), false);
723   if (EmittedArch == ARM::INVALID_ARCH)
724     setAttributeItem(CPU_arch, GetArchDefaultCPUArch(Arch), false);
725   else
726     setAttributeItem(CPU_arch, GetArchDefaultCPUArch(EmittedArch), false);
727 
728   switch (Arch) {
729   case ARM::ARMV2:
730   case ARM::ARMV2A:
731   case ARM::ARMV3:
732   case ARM::ARMV3M:
733   case ARM::ARMV4:
734   case ARM::ARMV5:
735     setAttributeItem(ARM_ISA_use, Allowed, false);
736     break;
737 
738   case ARM::ARMV4T:
739   case ARM::ARMV5T:
740   case ARM::ARMV5TE:
741   case ARM::ARMV6:
742   case ARM::ARMV6J:
743     setAttributeItem(ARM_ISA_use, Allowed, false);
744     setAttributeItem(THUMB_ISA_use, Allowed, false);
745     break;
746 
747   case ARM::ARMV6T2:
748     setAttributeItem(ARM_ISA_use, Allowed, false);
749     setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
750     break;
751 
752   case ARM::ARMV6Z:
753   case ARM::ARMV6ZK:
754     setAttributeItem(ARM_ISA_use, Allowed, false);
755     setAttributeItem(THUMB_ISA_use, Allowed, false);
756     setAttributeItem(Virtualization_use, AllowTZ, false);
757     break;
758 
759   case ARM::ARMV6M:
760     setAttributeItem(THUMB_ISA_use, Allowed, false);
761     break;
762 
763   case ARM::ARMV7:
764     setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
765     break;
766 
767   case ARM::ARMV7A:
768     setAttributeItem(CPU_arch_profile, ApplicationProfile, false);
769     setAttributeItem(ARM_ISA_use, Allowed, false);
770     setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
771     break;
772 
773   case ARM::ARMV7R:
774     setAttributeItem(CPU_arch_profile, RealTimeProfile, false);
775     setAttributeItem(ARM_ISA_use, Allowed, false);
776     setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
777     break;
778 
779   case ARM::ARMV7M:
780     setAttributeItem(CPU_arch_profile, MicroControllerProfile, false);
781     setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
782     break;
783 
784   case ARM::ARMV8A:
785     setAttributeItem(CPU_arch_profile, ApplicationProfile, false);
786     setAttributeItem(ARM_ISA_use, Allowed, false);
787     setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
788     setAttributeItem(MPextension_use, Allowed, false);
789     setAttributeItem(Virtualization_use, AllowTZVirtualization, false);
790     break;
791 
792   case ARM::IWMMXT:
793     setAttributeItem(ARM_ISA_use, Allowed, false);
794     setAttributeItem(THUMB_ISA_use, Allowed, false);
795     setAttributeItem(WMMX_arch, AllowWMMXv1, false);
796     break;
797 
798   case ARM::IWMMXT2:
799     setAttributeItem(ARM_ISA_use, Allowed, false);
800     setAttributeItem(THUMB_ISA_use, Allowed, false);
801     setAttributeItem(WMMX_arch, AllowWMMXv2, false);
802     break;
803 
804   default:
805     report_fatal_error("Unknown Arch: " + Twine(Arch));
806     break;
807   }
808 }
809 void ARMTargetELFStreamer::emitFPU(unsigned Value) {
810   FPU = Value;
811 }
812 void ARMTargetELFStreamer::emitFPUDefaultAttributes() {
813   switch (FPU) {
814   case ARM::VFP:
815   case ARM::VFPV2:
816     setAttributeItem(ARMBuildAttrs::FP_arch,
817                      ARMBuildAttrs::AllowFPv2,
818                      /* OverwriteExisting= */ false);
819     break;
820 
821   case ARM::VFPV3:
822     setAttributeItem(ARMBuildAttrs::FP_arch,
823                      ARMBuildAttrs::AllowFPv3A,
824                      /* OverwriteExisting= */ false);
825     break;
826 
827   case ARM::VFPV3_D16:
828     setAttributeItem(ARMBuildAttrs::FP_arch,
829                      ARMBuildAttrs::AllowFPv3B,
830                      /* OverwriteExisting= */ false);
831     break;
832 
833   case ARM::VFPV4:
834     setAttributeItem(ARMBuildAttrs::FP_arch,
835                      ARMBuildAttrs::AllowFPv4A,
836                      /* OverwriteExisting= */ false);
837     break;
838 
839   case ARM::VFPV4_D16:
840     setAttributeItem(ARMBuildAttrs::FP_arch,
841                      ARMBuildAttrs::AllowFPv4B,
842                      /* OverwriteExisting= */ false);
843     break;
844 
845   case ARM::FP_ARMV8:
846     setAttributeItem(ARMBuildAttrs::FP_arch,
847                      ARMBuildAttrs::AllowFPARMv8A,
848                      /* OverwriteExisting= */ false);
849     break;
850 
851   // FPV5_D16 is identical to FP_ARMV8 except for the number of D registers, so
852   // uses the FP_ARMV8_D16 build attribute.
853   case ARM::FPV5_D16:
854     setAttributeItem(ARMBuildAttrs::FP_arch,
855                      ARMBuildAttrs::AllowFPARMv8B,
856                      /* OverwriteExisting= */ false);
857     break;
858 
859   case ARM::NEON:
860     setAttributeItem(ARMBuildAttrs::FP_arch,
861                      ARMBuildAttrs::AllowFPv3A,
862                      /* OverwriteExisting= */ false);
863     setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
864                      ARMBuildAttrs::AllowNeon,
865                      /* OverwriteExisting= */ false);
866     break;
867 
868   case ARM::NEON_VFPV4:
869     setAttributeItem(ARMBuildAttrs::FP_arch,
870                      ARMBuildAttrs::AllowFPv4A,
871                      /* OverwriteExisting= */ false);
872     setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
873                      ARMBuildAttrs::AllowNeon2,
874                      /* OverwriteExisting= */ false);
875     break;
876 
877   case ARM::NEON_FP_ARMV8:
878   case ARM::CRYPTO_NEON_FP_ARMV8:
879     setAttributeItem(ARMBuildAttrs::FP_arch,
880                      ARMBuildAttrs::AllowFPARMv8A,
881                      /* OverwriteExisting= */ false);
882     setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
883                      ARMBuildAttrs::AllowNeonARMv8,
884                      /* OverwriteExisting= */ false);
885     break;
886 
887   case ARM::SOFTVFP:
888     break;
889 
890   default:
891     report_fatal_error("Unknown FPU: " + Twine(FPU));
892     break;
893   }
894 }
895 size_t ARMTargetELFStreamer::calculateContentSize() const {
896   size_t Result = 0;
897   for (size_t i = 0; i < Contents.size(); ++i) {
898     AttributeItem item = Contents[i];
899     switch (item.Type) {
900     case AttributeItem::HiddenAttribute:
901       break;
902     case AttributeItem::NumericAttribute:
903       Result += getULEB128Size(item.Tag);
904       Result += getULEB128Size(item.IntValue);
905       break;
906     case AttributeItem::TextAttribute:
907       Result += getULEB128Size(item.Tag);
908       Result += item.StringValue.size() + 1; // string + '\0'
909       break;
910     case AttributeItem::NumericAndTextAttributes:
911       Result += getULEB128Size(item.Tag);
912       Result += getULEB128Size(item.IntValue);
913       Result += item.StringValue.size() + 1; // string + '\0';
914       break;
915     }
916   }
917   return Result;
918 }
919 void ARMTargetELFStreamer::finishAttributeSection() {
920   // <format-version>
921   // [ <section-length> "vendor-name"
922   // [ <file-tag> <size> <attribute>*
923   //   | <section-tag> <size> <section-number>* 0 <attribute>*
924   //   | <symbol-tag> <size> <symbol-number>* 0 <attribute>*
925   //   ]+
926   // ]*
927 
928   if (FPU != ARM::INVALID_FPU)
929     emitFPUDefaultAttributes();
930 
931   if (Arch != ARM::INVALID_ARCH)
932     emitArchDefaultAttributes();
933 
934   if (Contents.empty())
935     return;
936 
937   std::sort(Contents.begin(), Contents.end(), AttributeItem::LessTag);
938 
939   ARMELFStreamer &Streamer = getStreamer();
940 
941   // Switch to .ARM.attributes section
942   if (AttributeSection) {
943     Streamer.SwitchSection(AttributeSection);
944   } else {
945     AttributeSection =
946       Streamer.getContext().getELFSection(".ARM.attributes",
947                                           ELF::SHT_ARM_ATTRIBUTES,
948                                           0,
949                                           SectionKind::getMetadata());
950     Streamer.SwitchSection(AttributeSection);
951 
952     // Format version
953     Streamer.EmitIntValue(0x41, 1);
954   }
955 
956   // Vendor size + Vendor name + '\0'
957   const size_t VendorHeaderSize = 4 + CurrentVendor.size() + 1;
958 
959   // Tag + Tag Size
960   const size_t TagHeaderSize = 1 + 4;
961 
962   const size_t ContentsSize = calculateContentSize();
963 
964   Streamer.EmitIntValue(VendorHeaderSize + TagHeaderSize + ContentsSize, 4);
965   Streamer.EmitBytes(CurrentVendor);
966   Streamer.EmitIntValue(0, 1); // '\0'
967 
968   Streamer.EmitIntValue(ARMBuildAttrs::File, 1);
969   Streamer.EmitIntValue(TagHeaderSize + ContentsSize, 4);
970 
971   // Size should have been accounted for already, now
972   // emit each field as its type (ULEB or String)
973   for (size_t i = 0; i < Contents.size(); ++i) {
974     AttributeItem item = Contents[i];
975     Streamer.EmitULEB128IntValue(item.Tag);
976     switch (item.Type) {
977     default: llvm_unreachable("Invalid attribute type");
978     case AttributeItem::NumericAttribute:
979       Streamer.EmitULEB128IntValue(item.IntValue);
980       break;
981     case AttributeItem::TextAttribute:
982       Streamer.EmitBytes(item.StringValue.upper());
983       Streamer.EmitIntValue(0, 1); // '\0'
984       break;
985     case AttributeItem::NumericAndTextAttributes:
986       Streamer.EmitULEB128IntValue(item.IntValue);
987       Streamer.EmitBytes(item.StringValue.upper());
988       Streamer.EmitIntValue(0, 1); // '\0'
989       break;
990     }
991   }
992 
993   Contents.clear();
994   FPU = ARM::INVALID_FPU;
995 }
996 
997 void ARMTargetELFStreamer::emitLabel(MCSymbol *Symbol) {
998   ARMELFStreamer &Streamer = getStreamer();
999   if (!Streamer.IsThumb)
1000     return;
1001 
1002   const MCSymbolData &SD = Streamer.getOrCreateSymbolData(Symbol);
1003   unsigned Type = MCELF::GetType(SD);
1004   if (Type == ELF_STT_Func || Type == ELF_STT_GnuIFunc)
1005     Streamer.EmitThumbFunc(Symbol);
1006 }
1007 
1008 void
1009 ARMTargetELFStreamer::AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *S) {
1010   getStreamer().EmitFixup(S, FK_Data_4);
1011 }
1012 
1013 void ARMTargetELFStreamer::emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) {
1014   if (const MCSymbolRefExpr *SRE = dyn_cast<MCSymbolRefExpr>(Value)) {
1015     const MCSymbol &Sym = SRE->getSymbol();
1016     if (!Sym.isDefined()) {
1017       getStreamer().EmitAssignment(Symbol, Value);
1018       return;
1019     }
1020   }
1021 
1022   getStreamer().EmitThumbFunc(Symbol);
1023   getStreamer().EmitAssignment(Symbol, Value);
1024 }
1025 
1026 void ARMTargetELFStreamer::emitInst(uint32_t Inst, char Suffix) {
1027   getStreamer().emitInst(Inst, Suffix);
1028 }
1029 
1030 void ARMELFStreamer::FinishImpl() {
1031   MCTargetStreamer &TS = *getTargetStreamer();
1032   ARMTargetStreamer &ATS = static_cast<ARMTargetStreamer &>(TS);
1033   ATS.finishAttributeSection();
1034 
1035   MCELFStreamer::FinishImpl();
1036 }
1037 
1038 inline void ARMELFStreamer::SwitchToEHSection(const char *Prefix,
1039                                               unsigned Type,
1040                                               unsigned Flags,
1041                                               SectionKind Kind,
1042                                               const MCSymbol &Fn) {
1043   const MCSectionELF &FnSection =
1044     static_cast<const MCSectionELF &>(Fn.getSection());
1045 
1046   // Create the name for new section
1047   StringRef FnSecName(FnSection.getSectionName());
1048   SmallString<128> EHSecName(Prefix);
1049   if (FnSecName != ".text") {
1050     EHSecName += FnSecName;
1051   }
1052 
1053   // Get .ARM.extab or .ARM.exidx section
1054   const MCSectionELF *EHSection = nullptr;
1055   if (const MCSymbol *Group = FnSection.getGroup()) {
1056     EHSection = getContext().getELFSection(
1057       EHSecName, Type, Flags | ELF::SHF_GROUP, Kind,
1058       FnSection.getEntrySize(), Group->getName());
1059   } else {
1060     EHSection = getContext().getELFSection(EHSecName, Type, Flags, Kind);
1061   }
1062   assert(EHSection && "Failed to get the required EH section");
1063 
1064   // Switch to .ARM.extab or .ARM.exidx section
1065   SwitchSection(EHSection);
1066   EmitCodeAlignment(4);
1067 }
1068 
1069 inline void ARMELFStreamer::SwitchToExTabSection(const MCSymbol &FnStart) {
1070   SwitchToEHSection(".ARM.extab",
1071                     ELF::SHT_PROGBITS,
1072                     ELF::SHF_ALLOC,
1073                     SectionKind::getDataRel(),
1074                     FnStart);
1075 }
1076 
1077 inline void ARMELFStreamer::SwitchToExIdxSection(const MCSymbol &FnStart) {
1078   SwitchToEHSection(".ARM.exidx",
1079                     ELF::SHT_ARM_EXIDX,
1080                     ELF::SHF_ALLOC | ELF::SHF_LINK_ORDER,
1081                     SectionKind::getDataRel(),
1082                     FnStart);
1083 }
1084 void ARMELFStreamer::EmitFixup(const MCExpr *Expr, MCFixupKind Kind) {
1085   MCDataFragment *Frag = getOrCreateDataFragment();
1086   Frag->getFixups().push_back(MCFixup::Create(Frag->getContents().size(), Expr,
1087                                               Kind));
1088 }
1089 
1090 void ARMELFStreamer::Reset() {
1091   ExTab = nullptr;
1092   FnStart = nullptr;
1093   Personality = nullptr;
1094   PersonalityIndex = ARM::EHABI::NUM_PERSONALITY_INDEX;
1095   FPReg = ARM::SP;
1096   FPOffset = 0;
1097   SPOffset = 0;
1098   PendingOffset = 0;
1099   UsedFP = false;
1100   CantUnwind = false;
1101 
1102   Opcodes.clear();
1103   UnwindOpAsm.Reset();
1104 }
1105 
1106 void ARMELFStreamer::emitFnStart() {
1107   assert(FnStart == nullptr);
1108   FnStart = getContext().CreateTempSymbol();
1109   EmitLabel(FnStart);
1110 }
1111 
1112 void ARMELFStreamer::emitFnEnd() {
1113   assert(FnStart && ".fnstart must precedes .fnend");
1114 
1115   // Emit unwind opcodes if there is no .handlerdata directive
1116   if (!ExTab && !CantUnwind)
1117     FlushUnwindOpcodes(true);
1118 
1119   // Emit the exception index table entry
1120   SwitchToExIdxSection(*FnStart);
1121 
1122   if (PersonalityIndex < ARM::EHABI::NUM_PERSONALITY_INDEX)
1123     EmitPersonalityFixup(GetAEABIUnwindPersonalityName(PersonalityIndex));
1124 
1125   const MCSymbolRefExpr *FnStartRef =
1126     MCSymbolRefExpr::Create(FnStart,
1127                             MCSymbolRefExpr::VK_ARM_PREL31,
1128                             getContext());
1129 
1130   EmitValue(FnStartRef, 4);
1131 
1132   if (CantUnwind) {
1133     EmitIntValue(ARM::EHABI::EXIDX_CANTUNWIND, 4);
1134   } else if (ExTab) {
1135     // Emit a reference to the unwind opcodes in the ".ARM.extab" section.
1136     const MCSymbolRefExpr *ExTabEntryRef =
1137       MCSymbolRefExpr::Create(ExTab,
1138                               MCSymbolRefExpr::VK_ARM_PREL31,
1139                               getContext());
1140     EmitValue(ExTabEntryRef, 4);
1141   } else {
1142     // For the __aeabi_unwind_cpp_pr0, we have to emit the unwind opcodes in
1143     // the second word of exception index table entry.  The size of the unwind
1144     // opcodes should always be 4 bytes.
1145     assert(PersonalityIndex == ARM::EHABI::AEABI_UNWIND_CPP_PR0 &&
1146            "Compact model must use __aeabi_unwind_cpp_pr0 as personality");
1147     assert(Opcodes.size() == 4u &&
1148            "Unwind opcode size for __aeabi_unwind_cpp_pr0 must be equal to 4");
1149     uint64_t Intval = Opcodes[0] |
1150                       Opcodes[1] << 8 |
1151                       Opcodes[2] << 16 |
1152                       Opcodes[3] << 24;
1153     EmitIntValue(Intval, Opcodes.size());
1154   }
1155 
1156   // Switch to the section containing FnStart
1157   SwitchSection(&FnStart->getSection());
1158 
1159   // Clean exception handling frame information
1160   Reset();
1161 }
1162 
1163 void ARMELFStreamer::emitCantUnwind() { CantUnwind = true; }
1164 
1165 // Add the R_ARM_NONE fixup at the same position
1166 void ARMELFStreamer::EmitPersonalityFixup(StringRef Name) {
1167   const MCSymbol *PersonalitySym = getContext().GetOrCreateSymbol(Name);
1168 
1169   const MCSymbolRefExpr *PersonalityRef = MCSymbolRefExpr::Create(
1170       PersonalitySym, MCSymbolRefExpr::VK_ARM_NONE, getContext());
1171 
1172   visitUsedExpr(*PersonalityRef);
1173   MCDataFragment *DF = getOrCreateDataFragment();
1174   DF->getFixups().push_back(MCFixup::Create(DF->getContents().size(),
1175                                             PersonalityRef,
1176                                             MCFixup::getKindForSize(4, false)));
1177 }
1178 
1179 void ARMELFStreamer::FlushPendingOffset() {
1180   if (PendingOffset != 0) {
1181     UnwindOpAsm.EmitSPOffset(-PendingOffset);
1182     PendingOffset = 0;
1183   }
1184 }
1185 
1186 void ARMELFStreamer::FlushUnwindOpcodes(bool NoHandlerData) {
1187   // Emit the unwind opcode to restore $sp.
1188   if (UsedFP) {
1189     const MCRegisterInfo *MRI = getContext().getRegisterInfo();
1190     int64_t LastRegSaveSPOffset = SPOffset - PendingOffset;
1191     UnwindOpAsm.EmitSPOffset(LastRegSaveSPOffset - FPOffset);
1192     UnwindOpAsm.EmitSetSP(MRI->getEncodingValue(FPReg));
1193   } else {
1194     FlushPendingOffset();
1195   }
1196 
1197   // Finalize the unwind opcode sequence
1198   UnwindOpAsm.Finalize(PersonalityIndex, Opcodes);
1199 
1200   // For compact model 0, we have to emit the unwind opcodes in the .ARM.exidx
1201   // section.  Thus, we don't have to create an entry in the .ARM.extab
1202   // section.
1203   if (NoHandlerData && PersonalityIndex == ARM::EHABI::AEABI_UNWIND_CPP_PR0)
1204     return;
1205 
1206   // Switch to .ARM.extab section.
1207   SwitchToExTabSection(*FnStart);
1208 
1209   // Create .ARM.extab label for offset in .ARM.exidx
1210   assert(!ExTab);
1211   ExTab = getContext().CreateTempSymbol();
1212   EmitLabel(ExTab);
1213 
1214   // Emit personality
1215   if (Personality) {
1216     const MCSymbolRefExpr *PersonalityRef =
1217       MCSymbolRefExpr::Create(Personality,
1218                               MCSymbolRefExpr::VK_ARM_PREL31,
1219                               getContext());
1220 
1221     EmitValue(PersonalityRef, 4);
1222   }
1223 
1224   // Emit unwind opcodes
1225   assert((Opcodes.size() % 4) == 0 &&
1226          "Unwind opcode size for __aeabi_cpp_unwind_pr0 must be multiple of 4");
1227   for (unsigned I = 0; I != Opcodes.size(); I += 4) {
1228     uint64_t Intval = Opcodes[I] |
1229                       Opcodes[I + 1] << 8 |
1230                       Opcodes[I + 2] << 16 |
1231                       Opcodes[I + 3] << 24;
1232     EmitIntValue(Intval, 4);
1233   }
1234 
1235   // According to ARM EHABI section 9.2, if the __aeabi_unwind_cpp_pr1() or
1236   // __aeabi_unwind_cpp_pr2() is used, then the handler data must be emitted
1237   // after the unwind opcodes.  The handler data consists of several 32-bit
1238   // words, and should be terminated by zero.
1239   //
1240   // In case that the .handlerdata directive is not specified by the
1241   // programmer, we should emit zero to terminate the handler data.
1242   if (NoHandlerData && !Personality)
1243     EmitIntValue(0, 4);
1244 }
1245 
1246 void ARMELFStreamer::emitHandlerData() { FlushUnwindOpcodes(false); }
1247 
1248 void ARMELFStreamer::emitPersonality(const MCSymbol *Per) {
1249   Personality = Per;
1250   UnwindOpAsm.setPersonality(Per);
1251 }
1252 
1253 void ARMELFStreamer::emitPersonalityIndex(unsigned Index) {
1254   assert(Index < ARM::EHABI::NUM_PERSONALITY_INDEX && "invalid index");
1255   PersonalityIndex = Index;
1256 }
1257 
1258 void ARMELFStreamer::emitSetFP(unsigned NewFPReg, unsigned NewSPReg,
1259                                int64_t Offset) {
1260   assert((NewSPReg == ARM::SP || NewSPReg == FPReg) &&
1261          "the operand of .setfp directive should be either $sp or $fp");
1262 
1263   UsedFP = true;
1264   FPReg = NewFPReg;
1265 
1266   if (NewSPReg == ARM::SP)
1267     FPOffset = SPOffset + Offset;
1268   else
1269     FPOffset += Offset;
1270 }
1271 
1272 void ARMELFStreamer::emitMovSP(unsigned Reg, int64_t Offset) {
1273   assert((Reg != ARM::SP && Reg != ARM::PC) &&
1274          "the operand of .movsp cannot be either sp or pc");
1275   assert(FPReg == ARM::SP && "current FP must be SP");
1276 
1277   FlushPendingOffset();
1278 
1279   FPReg = Reg;
1280   FPOffset = SPOffset + Offset;
1281 
1282   const MCRegisterInfo *MRI = getContext().getRegisterInfo();
1283   UnwindOpAsm.EmitSetSP(MRI->getEncodingValue(FPReg));
1284 }
1285 
1286 void ARMELFStreamer::emitPad(int64_t Offset) {
1287   // Track the change of the $sp offset
1288   SPOffset -= Offset;
1289 
1290   // To squash multiple .pad directives, we should delay the unwind opcode
1291   // until the .save, .vsave, .handlerdata, or .fnend directives.
1292   PendingOffset -= Offset;
1293 }
1294 
1295 void ARMELFStreamer::emitRegSave(const SmallVectorImpl<unsigned> &RegList,
1296                                  bool IsVector) {
1297   // Collect the registers in the register list
1298   unsigned Count = 0;
1299   uint32_t Mask = 0;
1300   const MCRegisterInfo *MRI = getContext().getRegisterInfo();
1301   for (size_t i = 0; i < RegList.size(); ++i) {
1302     unsigned Reg = MRI->getEncodingValue(RegList[i]);
1303     assert(Reg < (IsVector ? 32U : 16U) && "Register out of range");
1304     unsigned Bit = (1u << Reg);
1305     if ((Mask & Bit) == 0) {
1306       Mask |= Bit;
1307       ++Count;
1308     }
1309   }
1310 
1311   // Track the change the $sp offset: For the .save directive, the
1312   // corresponding push instruction will decrease the $sp by (4 * Count).
1313   // For the .vsave directive, the corresponding vpush instruction will
1314   // decrease $sp by (8 * Count).
1315   SPOffset -= Count * (IsVector ? 8 : 4);
1316 
1317   // Emit the opcode
1318   FlushPendingOffset();
1319   if (IsVector)
1320     UnwindOpAsm.EmitVFPRegSave(Mask);
1321   else
1322     UnwindOpAsm.EmitRegSave(Mask);
1323 }
1324 
1325 void ARMELFStreamer::emitUnwindRaw(int64_t Offset,
1326                                    const SmallVectorImpl<uint8_t> &Opcodes) {
1327   FlushPendingOffset();
1328   SPOffset = SPOffset - Offset;
1329   UnwindOpAsm.EmitRaw(Opcodes);
1330 }
1331 
1332 namespace llvm {
1333 
1334 MCStreamer *createMCAsmStreamer(MCContext &Ctx, formatted_raw_ostream &OS,
1335                                 bool isVerboseAsm, bool useDwarfDirectory,
1336                                 MCInstPrinter *InstPrint, MCCodeEmitter *CE,
1337                                 MCAsmBackend *TAB, bool ShowInst) {
1338   MCStreamer *S = llvm::createAsmStreamer(
1339       Ctx, OS, isVerboseAsm, useDwarfDirectory, InstPrint, CE, TAB, ShowInst);
1340   new ARMTargetAsmStreamer(*S, OS, *InstPrint, isVerboseAsm);
1341   return S;
1342 }
1343 
1344 MCStreamer *createARMNullStreamer(MCContext &Ctx) {
1345   MCStreamer *S = llvm::createNullStreamer(Ctx);
1346   new ARMTargetStreamer(*S);
1347   return S;
1348 }
1349 
1350 MCELFStreamer *createARMELFStreamer(MCContext &Context, MCAsmBackend &TAB,
1351                                     raw_ostream &OS, MCCodeEmitter *Emitter,
1352                                     bool RelaxAll, bool IsThumb) {
1353     ARMELFStreamer *S = new ARMELFStreamer(Context, TAB, OS, Emitter, IsThumb);
1354     new ARMTargetELFStreamer(*S);
1355     // FIXME: This should eventually end up somewhere else where more
1356     // intelligent flag decisions can be made. For now we are just maintaining
1357     // the status quo for ARM and setting EF_ARM_EABI_VER5 as the default.
1358     S->getAssembler().setELFHeaderEFlags(ELF::EF_ARM_EABI_VER5);
1359 
1360     if (RelaxAll)
1361       S->getAssembler().setRelaxAll(true);
1362     return S;
1363   }
1364 
1365 }
1366 
1367 
1368