1 //===- lib/MC/ARMELFStreamer.cpp - ELF Object Output for ARM --------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file assembles .s files and emits ARM ELF .o object files. Different
11 // from generic ELF streamer in emitting mapping symbols ($a, $t and $d) to
12 // delimit regions of data and code.
13 //
14 //===----------------------------------------------------------------------===//
15 
16 #include "ARMRegisterInfo.h"
17 #include "ARMUnwindOpAsm.h"
18 #include "llvm/ADT/DenseMap.h"
19 #include "llvm/ADT/SmallString.h"
20 #include "llvm/ADT/SmallVector.h"
21 #include "llvm/ADT/StringRef.h"
22 #include "llvm/ADT/Triple.h"
23 #include "llvm/ADT/Twine.h"
24 #include "llvm/BinaryFormat/ELF.h"
25 #include "llvm/MC/MCAsmBackend.h"
26 #include "llvm/MC/MCAsmInfo.h"
27 #include "llvm/MC/MCAssembler.h"
28 #include "llvm/MC/MCCodeEmitter.h"
29 #include "llvm/MC/MCContext.h"
30 #include "llvm/MC/MCELFStreamer.h"
31 #include "llvm/MC/MCExpr.h"
32 #include "llvm/MC/MCFixup.h"
33 #include "llvm/MC/MCFragment.h"
34 #include "llvm/MC/MCInst.h"
35 #include "llvm/MC/MCInstPrinter.h"
36 #include "llvm/MC/MCObjectWriter.h"
37 #include "llvm/MC/MCRegisterInfo.h"
38 #include "llvm/MC/MCSection.h"
39 #include "llvm/MC/MCSectionELF.h"
40 #include "llvm/MC/MCStreamer.h"
41 #include "llvm/MC/MCSubtargetInfo.h"
42 #include "llvm/MC/MCSymbol.h"
43 #include "llvm/MC/MCSymbolELF.h"
44 #include "llvm/MC/SectionKind.h"
45 #include "llvm/Support/ARMBuildAttributes.h"
46 #include "llvm/Support/ARMEHABI.h"
47 #include "llvm/Support/Casting.h"
48 #include "llvm/Support/ErrorHandling.h"
49 #include "llvm/Support/FormattedStream.h"
50 #include "llvm/Support/LEB128.h"
51 #include "llvm/Support/TargetParser.h"
52 #include "llvm/Support/raw_ostream.h"
53 #include <algorithm>
54 #include <cassert>
55 #include <climits>
56 #include <cstddef>
57 #include <cstdint>
58 #include <string>
59 
60 using namespace llvm;
61 
GetAEABIUnwindPersonalityName(unsigned Index)62 static std::string GetAEABIUnwindPersonalityName(unsigned Index) {
63   assert(Index < ARM::EHABI::NUM_PERSONALITY_INDEX &&
64          "Invalid personality index");
65   return (Twine("__aeabi_unwind_cpp_pr") + Twine(Index)).str();
66 }
67 
68 namespace {
69 
70 class ARMELFStreamer;
71 
72 class ARMTargetAsmStreamer : public ARMTargetStreamer {
73   formatted_raw_ostream &OS;
74   MCInstPrinter &InstPrinter;
75   bool IsVerboseAsm;
76 
77   void emitFnStart() override;
78   void emitFnEnd() override;
79   void emitCantUnwind() override;
80   void emitPersonality(const MCSymbol *Personality) override;
81   void emitPersonalityIndex(unsigned Index) override;
82   void emitHandlerData() override;
83   void emitSetFP(unsigned FpReg, unsigned SpReg, int64_t Offset = 0) override;
84   void emitMovSP(unsigned Reg, int64_t Offset = 0) override;
85   void emitPad(int64_t Offset) override;
86   void emitRegSave(const SmallVectorImpl<unsigned> &RegList,
87                    bool isVector) override;
88   void emitUnwindRaw(int64_t Offset,
89                      const SmallVectorImpl<uint8_t> &Opcodes) override;
90 
91   void switchVendor(StringRef Vendor) override;
92   void emitAttribute(unsigned Attribute, unsigned Value) override;
93   void emitTextAttribute(unsigned Attribute, StringRef String) override;
94   void emitIntTextAttribute(unsigned Attribute, unsigned IntValue,
95                             StringRef StringValue) override;
96   void emitArch(ARM::ArchKind Arch) override;
97   void emitArchExtension(unsigned ArchExt) override;
98   void emitObjectArch(ARM::ArchKind Arch) override;
99   void emitFPU(unsigned FPU) override;
100   void emitInst(uint32_t Inst, char Suffix = '\0') override;
101   void finishAttributeSection() override;
102 
103   void AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *SRE) override;
104   void emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) override;
105 
106 public:
107   ARMTargetAsmStreamer(MCStreamer &S, formatted_raw_ostream &OS,
108                        MCInstPrinter &InstPrinter, bool VerboseAsm);
109 };
110 
ARMTargetAsmStreamer(MCStreamer & S,formatted_raw_ostream & OS,MCInstPrinter & InstPrinter,bool VerboseAsm)111 ARMTargetAsmStreamer::ARMTargetAsmStreamer(MCStreamer &S,
112                                            formatted_raw_ostream &OS,
113                                            MCInstPrinter &InstPrinter,
114                                            bool VerboseAsm)
115     : ARMTargetStreamer(S), OS(OS), InstPrinter(InstPrinter),
116       IsVerboseAsm(VerboseAsm) {}
117 
emitFnStart()118 void ARMTargetAsmStreamer::emitFnStart() { OS << "\t.fnstart\n"; }
emitFnEnd()119 void ARMTargetAsmStreamer::emitFnEnd() { OS << "\t.fnend\n"; }
emitCantUnwind()120 void ARMTargetAsmStreamer::emitCantUnwind() { OS << "\t.cantunwind\n"; }
121 
emitPersonality(const MCSymbol * Personality)122 void ARMTargetAsmStreamer::emitPersonality(const MCSymbol *Personality) {
123   OS << "\t.personality " << Personality->getName() << '\n';
124 }
125 
emitPersonalityIndex(unsigned Index)126 void ARMTargetAsmStreamer::emitPersonalityIndex(unsigned Index) {
127   OS << "\t.personalityindex " << Index << '\n';
128 }
129 
emitHandlerData()130 void ARMTargetAsmStreamer::emitHandlerData() { OS << "\t.handlerdata\n"; }
131 
emitSetFP(unsigned FpReg,unsigned SpReg,int64_t Offset)132 void ARMTargetAsmStreamer::emitSetFP(unsigned FpReg, unsigned SpReg,
133                                      int64_t Offset) {
134   OS << "\t.setfp\t";
135   InstPrinter.printRegName(OS, FpReg);
136   OS << ", ";
137   InstPrinter.printRegName(OS, SpReg);
138   if (Offset)
139     OS << ", #" << Offset;
140   OS << '\n';
141 }
142 
emitMovSP(unsigned Reg,int64_t Offset)143 void ARMTargetAsmStreamer::emitMovSP(unsigned Reg, int64_t Offset) {
144   assert((Reg != ARM::SP && Reg != ARM::PC) &&
145          "the operand of .movsp cannot be either sp or pc");
146 
147   OS << "\t.movsp\t";
148   InstPrinter.printRegName(OS, Reg);
149   if (Offset)
150     OS << ", #" << Offset;
151   OS << '\n';
152 }
153 
emitPad(int64_t Offset)154 void ARMTargetAsmStreamer::emitPad(int64_t Offset) {
155   OS << "\t.pad\t#" << Offset << '\n';
156 }
157 
emitRegSave(const SmallVectorImpl<unsigned> & RegList,bool isVector)158 void ARMTargetAsmStreamer::emitRegSave(const SmallVectorImpl<unsigned> &RegList,
159                                        bool isVector) {
160   assert(RegList.size() && "RegList should not be empty");
161   if (isVector)
162     OS << "\t.vsave\t{";
163   else
164     OS << "\t.save\t{";
165 
166   InstPrinter.printRegName(OS, RegList[0]);
167 
168   for (unsigned i = 1, e = RegList.size(); i != e; ++i) {
169     OS << ", ";
170     InstPrinter.printRegName(OS, RegList[i]);
171   }
172 
173   OS << "}\n";
174 }
175 
switchVendor(StringRef Vendor)176 void ARMTargetAsmStreamer::switchVendor(StringRef Vendor) {}
177 
emitAttribute(unsigned Attribute,unsigned Value)178 void ARMTargetAsmStreamer::emitAttribute(unsigned Attribute, unsigned Value) {
179   OS << "\t.eabi_attribute\t" << Attribute << ", " << Twine(Value);
180   if (IsVerboseAsm) {
181     StringRef Name = ARMBuildAttrs::AttrTypeAsString(Attribute);
182     if (!Name.empty())
183       OS << "\t@ " << Name;
184   }
185   OS << "\n";
186 }
187 
emitTextAttribute(unsigned Attribute,StringRef String)188 void ARMTargetAsmStreamer::emitTextAttribute(unsigned Attribute,
189                                              StringRef String) {
190   switch (Attribute) {
191   case ARMBuildAttrs::CPU_name:
192     OS << "\t.cpu\t" << String.lower();
193     break;
194   default:
195     OS << "\t.eabi_attribute\t" << Attribute << ", \"" << String << "\"";
196     if (IsVerboseAsm) {
197       StringRef Name = ARMBuildAttrs::AttrTypeAsString(Attribute);
198       if (!Name.empty())
199         OS << "\t@ " << Name;
200     }
201     break;
202   }
203   OS << "\n";
204 }
205 
emitIntTextAttribute(unsigned Attribute,unsigned IntValue,StringRef StringValue)206 void ARMTargetAsmStreamer::emitIntTextAttribute(unsigned Attribute,
207                                                 unsigned IntValue,
208                                                 StringRef StringValue) {
209   switch (Attribute) {
210   default: llvm_unreachable("unsupported multi-value attribute in asm mode");
211   case ARMBuildAttrs::compatibility:
212     OS << "\t.eabi_attribute\t" << Attribute << ", " << IntValue;
213     if (!StringValue.empty())
214       OS << ", \"" << StringValue << "\"";
215     if (IsVerboseAsm)
216       OS << "\t@ " << ARMBuildAttrs::AttrTypeAsString(Attribute);
217     break;
218   }
219   OS << "\n";
220 }
221 
emitArch(ARM::ArchKind Arch)222 void ARMTargetAsmStreamer::emitArch(ARM::ArchKind Arch) {
223   OS << "\t.arch\t" << ARM::getArchName(Arch) << "\n";
224 }
225 
emitArchExtension(unsigned ArchExt)226 void ARMTargetAsmStreamer::emitArchExtension(unsigned ArchExt) {
227   OS << "\t.arch_extension\t" << ARM::getArchExtName(ArchExt) << "\n";
228 }
229 
emitObjectArch(ARM::ArchKind Arch)230 void ARMTargetAsmStreamer::emitObjectArch(ARM::ArchKind Arch) {
231   OS << "\t.object_arch\t" << ARM::getArchName(Arch) << '\n';
232 }
233 
emitFPU(unsigned FPU)234 void ARMTargetAsmStreamer::emitFPU(unsigned FPU) {
235   OS << "\t.fpu\t" << ARM::getFPUName(FPU) << "\n";
236 }
237 
finishAttributeSection()238 void ARMTargetAsmStreamer::finishAttributeSection() {}
239 
240 void
AnnotateTLSDescriptorSequence(const MCSymbolRefExpr * S)241 ARMTargetAsmStreamer::AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *S) {
242   OS << "\t.tlsdescseq\t" << S->getSymbol().getName();
243 }
244 
emitThumbSet(MCSymbol * Symbol,const MCExpr * Value)245 void ARMTargetAsmStreamer::emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) {
246   const MCAsmInfo *MAI = Streamer.getContext().getAsmInfo();
247 
248   OS << "\t.thumb_set\t";
249   Symbol->print(OS, MAI);
250   OS << ", ";
251   Value->print(OS, MAI);
252   OS << '\n';
253 }
254 
emitInst(uint32_t Inst,char Suffix)255 void ARMTargetAsmStreamer::emitInst(uint32_t Inst, char Suffix) {
256   OS << "\t.inst";
257   if (Suffix)
258     OS << "." << Suffix;
259   OS << "\t0x" << Twine::utohexstr(Inst) << "\n";
260 }
261 
emitUnwindRaw(int64_t Offset,const SmallVectorImpl<uint8_t> & Opcodes)262 void ARMTargetAsmStreamer::emitUnwindRaw(int64_t Offset,
263                                       const SmallVectorImpl<uint8_t> &Opcodes) {
264   OS << "\t.unwind_raw " << Offset;
265   for (SmallVectorImpl<uint8_t>::const_iterator OCI = Opcodes.begin(),
266                                                 OCE = Opcodes.end();
267        OCI != OCE; ++OCI)
268     OS << ", 0x" << Twine::utohexstr(*OCI);
269   OS << '\n';
270 }
271 
272 class ARMTargetELFStreamer : public ARMTargetStreamer {
273 private:
274   // This structure holds all attributes, accounting for
275   // their string/numeric value, so we can later emit them
276   // in declaration order, keeping all in the same vector
277   struct AttributeItem {
278     enum {
279       HiddenAttribute = 0,
280       NumericAttribute,
281       TextAttribute,
282       NumericAndTextAttributes
283     } Type;
284     unsigned Tag;
285     unsigned IntValue;
286     std::string StringValue;
287 
LessTag__anonb90111790111::ARMTargetELFStreamer::AttributeItem288     static bool LessTag(const AttributeItem &LHS, const AttributeItem &RHS) {
289       // The conformance tag must be emitted first when serialised
290       // into an object file. Specifically, the addenda to the ARM ABI
291       // states that (2.3.7.4):
292       //
293       // "To simplify recognition by consumers in the common case of
294       // claiming conformity for the whole file, this tag should be
295       // emitted first in a file-scope sub-subsection of the first
296       // public subsection of the attributes section."
297       //
298       // So it is special-cased in this comparison predicate when the
299       // attributes are sorted in finishAttributeSection().
300       return (RHS.Tag != ARMBuildAttrs::conformance) &&
301              ((LHS.Tag == ARMBuildAttrs::conformance) || (LHS.Tag < RHS.Tag));
302     }
303   };
304 
305   StringRef CurrentVendor;
306   unsigned FPU = ARM::FK_INVALID;
307   ARM::ArchKind Arch = ARM::ArchKind::INVALID;
308   ARM::ArchKind EmittedArch = ARM::ArchKind::INVALID;
309   SmallVector<AttributeItem, 64> Contents;
310 
311   MCSection *AttributeSection = nullptr;
312 
getAttributeItem(unsigned Attribute)313   AttributeItem *getAttributeItem(unsigned Attribute) {
314     for (size_t i = 0; i < Contents.size(); ++i)
315       if (Contents[i].Tag == Attribute)
316         return &Contents[i];
317     return nullptr;
318   }
319 
setAttributeItem(unsigned Attribute,unsigned Value,bool OverwriteExisting)320   void setAttributeItem(unsigned Attribute, unsigned Value,
321                         bool OverwriteExisting) {
322     // Look for existing attribute item
323     if (AttributeItem *Item = getAttributeItem(Attribute)) {
324       if (!OverwriteExisting)
325         return;
326       Item->Type = AttributeItem::NumericAttribute;
327       Item->IntValue = Value;
328       return;
329     }
330 
331     // Create new attribute item
332     AttributeItem Item = {
333       AttributeItem::NumericAttribute,
334       Attribute,
335       Value,
336       StringRef("")
337     };
338     Contents.push_back(Item);
339   }
340 
setAttributeItem(unsigned Attribute,StringRef Value,bool OverwriteExisting)341   void setAttributeItem(unsigned Attribute, StringRef Value,
342                         bool OverwriteExisting) {
343     // Look for existing attribute item
344     if (AttributeItem *Item = getAttributeItem(Attribute)) {
345       if (!OverwriteExisting)
346         return;
347       Item->Type = AttributeItem::TextAttribute;
348       Item->StringValue = Value;
349       return;
350     }
351 
352     // Create new attribute item
353     AttributeItem Item = {
354       AttributeItem::TextAttribute,
355       Attribute,
356       0,
357       Value
358     };
359     Contents.push_back(Item);
360   }
361 
setAttributeItems(unsigned Attribute,unsigned IntValue,StringRef StringValue,bool OverwriteExisting)362   void setAttributeItems(unsigned Attribute, unsigned IntValue,
363                          StringRef StringValue, bool OverwriteExisting) {
364     // Look for existing attribute item
365     if (AttributeItem *Item = getAttributeItem(Attribute)) {
366       if (!OverwriteExisting)
367         return;
368       Item->Type = AttributeItem::NumericAndTextAttributes;
369       Item->IntValue = IntValue;
370       Item->StringValue = StringValue;
371       return;
372     }
373 
374     // Create new attribute item
375     AttributeItem Item = {
376       AttributeItem::NumericAndTextAttributes,
377       Attribute,
378       IntValue,
379       StringValue
380     };
381     Contents.push_back(Item);
382   }
383 
384   void emitArchDefaultAttributes();
385   void emitFPUDefaultAttributes();
386 
387   ARMELFStreamer &getStreamer();
388 
389   void emitFnStart() override;
390   void emitFnEnd() override;
391   void emitCantUnwind() override;
392   void emitPersonality(const MCSymbol *Personality) override;
393   void emitPersonalityIndex(unsigned Index) override;
394   void emitHandlerData() override;
395   void emitSetFP(unsigned FpReg, unsigned SpReg, int64_t Offset = 0) override;
396   void emitMovSP(unsigned Reg, int64_t Offset = 0) override;
397   void emitPad(int64_t Offset) override;
398   void emitRegSave(const SmallVectorImpl<unsigned> &RegList,
399                    bool isVector) override;
400   void emitUnwindRaw(int64_t Offset,
401                      const SmallVectorImpl<uint8_t> &Opcodes) override;
402 
403   void switchVendor(StringRef Vendor) override;
404   void emitAttribute(unsigned Attribute, unsigned Value) override;
405   void emitTextAttribute(unsigned Attribute, StringRef String) override;
406   void emitIntTextAttribute(unsigned Attribute, unsigned IntValue,
407                             StringRef StringValue) override;
408   void emitArch(ARM::ArchKind Arch) override;
409   void emitObjectArch(ARM::ArchKind Arch) override;
410   void emitFPU(unsigned FPU) override;
411   void emitInst(uint32_t Inst, char Suffix = '\0') override;
412   void finishAttributeSection() override;
413   void emitLabel(MCSymbol *Symbol) override;
414 
415   void AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *SRE) override;
416   void emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) override;
417 
418   size_t calculateContentSize() const;
419 
420   // Reset state between object emissions
421   void reset() override;
422 
423 public:
ARMTargetELFStreamer(MCStreamer & S)424   ARMTargetELFStreamer(MCStreamer &S)
425     : ARMTargetStreamer(S), CurrentVendor("aeabi") {}
426 };
427 
428 /// Extend the generic ELFStreamer class so that it can emit mapping symbols at
429 /// the appropriate points in the object files. These symbols are defined in the
430 /// ARM ELF ABI: infocenter.arm.com/help/topic/com.arm.../IHI0044D_aaelf.pdf.
431 ///
432 /// In brief: $a, $t or $d should be emitted at the start of each contiguous
433 /// region of ARM code, Thumb code or data in a section. In practice, this
434 /// emission does not rely on explicit assembler directives but on inherent
435 /// properties of the directives doing the emission (e.g. ".byte" is data, "add
436 /// r0, r0, r0" an instruction).
437 ///
438 /// As a result this system is orthogonal to the DataRegion infrastructure used
439 /// by MachO. Beware!
440 class ARMELFStreamer : public MCELFStreamer {
441 public:
442   friend class ARMTargetELFStreamer;
443 
ARMELFStreamer(MCContext & Context,std::unique_ptr<MCAsmBackend> TAB,std::unique_ptr<MCObjectWriter> OW,std::unique_ptr<MCCodeEmitter> Emitter,bool IsThumb)444   ARMELFStreamer(MCContext &Context, std::unique_ptr<MCAsmBackend> TAB,
445                  std::unique_ptr<MCObjectWriter> OW, std::unique_ptr<MCCodeEmitter> Emitter,
446                  bool IsThumb)
447       : MCELFStreamer(Context, std::move(TAB), std::move(OW), std::move(Emitter)),
448         IsThumb(IsThumb) {
449     EHReset();
450   }
451 
452   ~ARMELFStreamer() override = default;
453 
454   void FinishImpl() override;
455 
456   // ARM exception handling directives
457   void emitFnStart();
458   void emitFnEnd();
459   void emitCantUnwind();
460   void emitPersonality(const MCSymbol *Per);
461   void emitPersonalityIndex(unsigned index);
462   void emitHandlerData();
463   void emitSetFP(unsigned NewFpReg, unsigned NewSpReg, int64_t Offset = 0);
464   void emitMovSP(unsigned Reg, int64_t Offset = 0);
465   void emitPad(int64_t Offset);
466   void emitRegSave(const SmallVectorImpl<unsigned> &RegList, bool isVector);
467   void emitUnwindRaw(int64_t Offset, const SmallVectorImpl<uint8_t> &Opcodes);
emitFill(const MCExpr & NumBytes,uint64_t FillValue,SMLoc Loc)468   void emitFill(const MCExpr &NumBytes, uint64_t FillValue,
469                 SMLoc Loc) override {
470     EmitDataMappingSymbol();
471     MCObjectStreamer::emitFill(NumBytes, FillValue, Loc);
472   }
473 
ChangeSection(MCSection * Section,const MCExpr * Subsection)474   void ChangeSection(MCSection *Section, const MCExpr *Subsection) override {
475     LastMappingSymbols[getCurrentSection().first] = std::move(LastEMSInfo);
476     MCELFStreamer::ChangeSection(Section, Subsection);
477     auto LastMappingSymbol = LastMappingSymbols.find(Section);
478     if (LastMappingSymbol != LastMappingSymbols.end()) {
479       LastEMSInfo = std::move(LastMappingSymbol->second);
480       return;
481     }
482     LastEMSInfo.reset(new ElfMappingSymbolInfo(SMLoc(), nullptr, 0));
483   }
484 
485   /// This function is the one used to emit instruction data into the ELF
486   /// streamer. We override it to add the appropriate mapping symbol if
487   /// necessary.
EmitInstruction(const MCInst & Inst,const MCSubtargetInfo & STI,bool)488   void EmitInstruction(const MCInst &Inst, const MCSubtargetInfo &STI,
489                        bool) override {
490     if (IsThumb)
491       EmitThumbMappingSymbol();
492     else
493       EmitARMMappingSymbol();
494 
495     MCELFStreamer::EmitInstruction(Inst, STI);
496   }
497 
emitInst(uint32_t Inst,char Suffix)498   void emitInst(uint32_t Inst, char Suffix) {
499     unsigned Size;
500     char Buffer[4];
501     const bool LittleEndian = getContext().getAsmInfo()->isLittleEndian();
502 
503     switch (Suffix) {
504     case '\0':
505       Size = 4;
506 
507       assert(!IsThumb);
508       EmitARMMappingSymbol();
509       for (unsigned II = 0, IE = Size; II != IE; II++) {
510         const unsigned I = LittleEndian ? (Size - II - 1) : II;
511         Buffer[Size - II - 1] = uint8_t(Inst >> I * CHAR_BIT);
512       }
513 
514       break;
515     case 'n':
516     case 'w':
517       Size = (Suffix == 'n' ? 2 : 4);
518 
519       assert(IsThumb);
520       EmitThumbMappingSymbol();
521       // Thumb wide instructions are emitted as a pair of 16-bit words of the
522       // appropriate endianness.
523       for (unsigned II = 0, IE = Size; II != IE; II = II + 2) {
524         const unsigned I0 = LittleEndian ? II + 0 : II + 1;
525         const unsigned I1 = LittleEndian ? II + 1 : II + 0;
526         Buffer[Size - II - 2] = uint8_t(Inst >> I0 * CHAR_BIT);
527         Buffer[Size - II - 1] = uint8_t(Inst >> I1 * CHAR_BIT);
528       }
529 
530       break;
531     default:
532       llvm_unreachable("Invalid Suffix");
533     }
534 
535     MCELFStreamer::EmitBytes(StringRef(Buffer, Size));
536   }
537 
538   /// This is one of the functions used to emit data into an ELF section, so the
539   /// ARM streamer overrides it to add the appropriate mapping symbol ($d) if
540   /// necessary.
EmitBytes(StringRef Data)541   void EmitBytes(StringRef Data) override {
542     EmitDataMappingSymbol();
543     MCELFStreamer::EmitBytes(Data);
544   }
545 
FlushPendingMappingSymbol()546   void FlushPendingMappingSymbol() {
547     if (!LastEMSInfo->hasInfo())
548       return;
549     ElfMappingSymbolInfo *EMS = LastEMSInfo.get();
550     EmitMappingSymbol("$d", EMS->Loc, EMS->F, EMS->Offset);
551     EMS->resetInfo();
552   }
553 
554   /// This is one of the functions used to emit data into an ELF section, so the
555   /// ARM streamer overrides it to add the appropriate mapping symbol ($d) if
556   /// necessary.
EmitValueImpl(const MCExpr * Value,unsigned Size,SMLoc Loc)557   void EmitValueImpl(const MCExpr *Value, unsigned Size, SMLoc Loc) override {
558     if (const MCSymbolRefExpr *SRE = dyn_cast_or_null<MCSymbolRefExpr>(Value)) {
559       if (SRE->getKind() == MCSymbolRefExpr::VK_ARM_SBREL && !(Size == 4)) {
560         getContext().reportError(Loc, "relocated expression must be 32-bit");
561         return;
562       }
563       getOrCreateDataFragment();
564     }
565 
566     EmitDataMappingSymbol();
567     MCELFStreamer::EmitValueImpl(Value, Size, Loc);
568   }
569 
EmitAssemblerFlag(MCAssemblerFlag Flag)570   void EmitAssemblerFlag(MCAssemblerFlag Flag) override {
571     MCELFStreamer::EmitAssemblerFlag(Flag);
572 
573     switch (Flag) {
574     case MCAF_SyntaxUnified:
575       return; // no-op here.
576     case MCAF_Code16:
577       IsThumb = true;
578       return; // Change to Thumb mode
579     case MCAF_Code32:
580       IsThumb = false;
581       return; // Change to ARM mode
582     case MCAF_Code64:
583       return;
584     case MCAF_SubsectionsViaSymbols:
585       return;
586     }
587   }
588 
589 private:
590   enum ElfMappingSymbol {
591     EMS_None,
592     EMS_ARM,
593     EMS_Thumb,
594     EMS_Data
595   };
596 
597   struct ElfMappingSymbolInfo {
ElfMappingSymbolInfo__anonb90111790111::ARMELFStreamer::ElfMappingSymbolInfo598     explicit ElfMappingSymbolInfo(SMLoc Loc, MCFragment *F, uint64_t O)
599         : Loc(Loc), F(F), Offset(O), State(EMS_None) {}
resetInfo__anonb90111790111::ARMELFStreamer::ElfMappingSymbolInfo600     void resetInfo() {
601       F = nullptr;
602       Offset = 0;
603     }
hasInfo__anonb90111790111::ARMELFStreamer::ElfMappingSymbolInfo604     bool hasInfo() { return F != nullptr; }
605     SMLoc Loc;
606     MCFragment *F;
607     uint64_t Offset;
608     ElfMappingSymbol State;
609   };
610 
EmitDataMappingSymbol()611   void EmitDataMappingSymbol() {
612     if (LastEMSInfo->State == EMS_Data)
613       return;
614     else if (LastEMSInfo->State == EMS_None) {
615       // This is a tentative symbol, it won't really be emitted until it's
616       // actually needed.
617       ElfMappingSymbolInfo *EMS = LastEMSInfo.get();
618       auto *DF = dyn_cast_or_null<MCDataFragment>(getCurrentFragment());
619       if (!DF)
620         return;
621       EMS->Loc = SMLoc();
622       EMS->F = getCurrentFragment();
623       EMS->Offset = DF->getContents().size();
624       LastEMSInfo->State = EMS_Data;
625       return;
626     }
627     EmitMappingSymbol("$d");
628     LastEMSInfo->State = EMS_Data;
629   }
630 
EmitThumbMappingSymbol()631   void EmitThumbMappingSymbol() {
632     if (LastEMSInfo->State == EMS_Thumb)
633       return;
634     FlushPendingMappingSymbol();
635     EmitMappingSymbol("$t");
636     LastEMSInfo->State = EMS_Thumb;
637   }
638 
EmitARMMappingSymbol()639   void EmitARMMappingSymbol() {
640     if (LastEMSInfo->State == EMS_ARM)
641       return;
642     FlushPendingMappingSymbol();
643     EmitMappingSymbol("$a");
644     LastEMSInfo->State = EMS_ARM;
645   }
646 
EmitMappingSymbol(StringRef Name)647   void EmitMappingSymbol(StringRef Name) {
648     auto *Symbol = cast<MCSymbolELF>(getContext().getOrCreateSymbol(
649         Name + "." + Twine(MappingSymbolCounter++)));
650     EmitLabel(Symbol);
651 
652     Symbol->setType(ELF::STT_NOTYPE);
653     Symbol->setBinding(ELF::STB_LOCAL);
654     Symbol->setExternal(false);
655   }
656 
EmitMappingSymbol(StringRef Name,SMLoc Loc,MCFragment * F,uint64_t Offset)657   void EmitMappingSymbol(StringRef Name, SMLoc Loc, MCFragment *F,
658                          uint64_t Offset) {
659     auto *Symbol = cast<MCSymbolELF>(getContext().getOrCreateSymbol(
660         Name + "." + Twine(MappingSymbolCounter++)));
661     EmitLabel(Symbol, Loc, F);
662     Symbol->setType(ELF::STT_NOTYPE);
663     Symbol->setBinding(ELF::STB_LOCAL);
664     Symbol->setExternal(false);
665     Symbol->setOffset(Offset);
666   }
667 
EmitThumbFunc(MCSymbol * Func)668   void EmitThumbFunc(MCSymbol *Func) override {
669     getAssembler().setIsThumbFunc(Func);
670     EmitSymbolAttribute(Func, MCSA_ELF_TypeFunction);
671   }
672 
673   // Helper functions for ARM exception handling directives
674   void EHReset();
675 
676   // Reset state between object emissions
677   void reset() override;
678 
679   void EmitPersonalityFixup(StringRef Name);
680   void FlushPendingOffset();
681   void FlushUnwindOpcodes(bool NoHandlerData);
682 
683   void SwitchToEHSection(StringRef Prefix, unsigned Type, unsigned Flags,
684                          SectionKind Kind, const MCSymbol &Fn);
685   void SwitchToExTabSection(const MCSymbol &FnStart);
686   void SwitchToExIdxSection(const MCSymbol &FnStart);
687 
688   void EmitFixup(const MCExpr *Expr, MCFixupKind Kind);
689 
690   bool IsThumb;
691   int64_t MappingSymbolCounter = 0;
692 
693   DenseMap<const MCSection *, std::unique_ptr<ElfMappingSymbolInfo>>
694       LastMappingSymbols;
695 
696   std::unique_ptr<ElfMappingSymbolInfo> LastEMSInfo;
697 
698   // ARM Exception Handling Frame Information
699   MCSymbol *ExTab;
700   MCSymbol *FnStart;
701   const MCSymbol *Personality;
702   unsigned PersonalityIndex;
703   unsigned FPReg; // Frame pointer register
704   int64_t FPOffset; // Offset: (final frame pointer) - (initial $sp)
705   int64_t SPOffset; // Offset: (final $sp) - (initial $sp)
706   int64_t PendingOffset; // Offset: (final $sp) - (emitted $sp)
707   bool UsedFP;
708   bool CantUnwind;
709   SmallVector<uint8_t, 64> Opcodes;
710   UnwindOpcodeAssembler UnwindOpAsm;
711 };
712 
713 } // end anonymous namespace
714 
getStreamer()715 ARMELFStreamer &ARMTargetELFStreamer::getStreamer() {
716   return static_cast<ARMELFStreamer &>(Streamer);
717 }
718 
emitFnStart()719 void ARMTargetELFStreamer::emitFnStart() { getStreamer().emitFnStart(); }
emitFnEnd()720 void ARMTargetELFStreamer::emitFnEnd() { getStreamer().emitFnEnd(); }
emitCantUnwind()721 void ARMTargetELFStreamer::emitCantUnwind() { getStreamer().emitCantUnwind(); }
722 
emitPersonality(const MCSymbol * Personality)723 void ARMTargetELFStreamer::emitPersonality(const MCSymbol *Personality) {
724   getStreamer().emitPersonality(Personality);
725 }
726 
emitPersonalityIndex(unsigned Index)727 void ARMTargetELFStreamer::emitPersonalityIndex(unsigned Index) {
728   getStreamer().emitPersonalityIndex(Index);
729 }
730 
emitHandlerData()731 void ARMTargetELFStreamer::emitHandlerData() {
732   getStreamer().emitHandlerData();
733 }
734 
emitSetFP(unsigned FpReg,unsigned SpReg,int64_t Offset)735 void ARMTargetELFStreamer::emitSetFP(unsigned FpReg, unsigned SpReg,
736                                      int64_t Offset) {
737   getStreamer().emitSetFP(FpReg, SpReg, Offset);
738 }
739 
emitMovSP(unsigned Reg,int64_t Offset)740 void ARMTargetELFStreamer::emitMovSP(unsigned Reg, int64_t Offset) {
741   getStreamer().emitMovSP(Reg, Offset);
742 }
743 
emitPad(int64_t Offset)744 void ARMTargetELFStreamer::emitPad(int64_t Offset) {
745   getStreamer().emitPad(Offset);
746 }
747 
emitRegSave(const SmallVectorImpl<unsigned> & RegList,bool isVector)748 void ARMTargetELFStreamer::emitRegSave(const SmallVectorImpl<unsigned> &RegList,
749                                        bool isVector) {
750   getStreamer().emitRegSave(RegList, isVector);
751 }
752 
emitUnwindRaw(int64_t Offset,const SmallVectorImpl<uint8_t> & Opcodes)753 void ARMTargetELFStreamer::emitUnwindRaw(int64_t Offset,
754                                       const SmallVectorImpl<uint8_t> &Opcodes) {
755   getStreamer().emitUnwindRaw(Offset, Opcodes);
756 }
757 
switchVendor(StringRef Vendor)758 void ARMTargetELFStreamer::switchVendor(StringRef Vendor) {
759   assert(!Vendor.empty() && "Vendor cannot be empty.");
760 
761   if (CurrentVendor == Vendor)
762     return;
763 
764   if (!CurrentVendor.empty())
765     finishAttributeSection();
766 
767   assert(Contents.empty() &&
768          ".ARM.attributes should be flushed before changing vendor");
769   CurrentVendor = Vendor;
770 
771 }
772 
emitAttribute(unsigned Attribute,unsigned Value)773 void ARMTargetELFStreamer::emitAttribute(unsigned Attribute, unsigned Value) {
774   setAttributeItem(Attribute, Value, /* OverwriteExisting= */ true);
775 }
776 
emitTextAttribute(unsigned Attribute,StringRef Value)777 void ARMTargetELFStreamer::emitTextAttribute(unsigned Attribute,
778                                              StringRef Value) {
779   setAttributeItem(Attribute, Value, /* OverwriteExisting= */ true);
780 }
781 
emitIntTextAttribute(unsigned Attribute,unsigned IntValue,StringRef StringValue)782 void ARMTargetELFStreamer::emitIntTextAttribute(unsigned Attribute,
783                                                 unsigned IntValue,
784                                                 StringRef StringValue) {
785   setAttributeItems(Attribute, IntValue, StringValue,
786                     /* OverwriteExisting= */ true);
787 }
788 
emitArch(ARM::ArchKind Value)789 void ARMTargetELFStreamer::emitArch(ARM::ArchKind Value) {
790   Arch = Value;
791 }
792 
emitObjectArch(ARM::ArchKind Value)793 void ARMTargetELFStreamer::emitObjectArch(ARM::ArchKind Value) {
794   EmittedArch = Value;
795 }
796 
emitArchDefaultAttributes()797 void ARMTargetELFStreamer::emitArchDefaultAttributes() {
798   using namespace ARMBuildAttrs;
799 
800   setAttributeItem(CPU_name,
801                    ARM::getCPUAttr(Arch),
802                    false);
803 
804   if (EmittedArch == ARM::ArchKind::INVALID)
805     setAttributeItem(CPU_arch,
806                      ARM::getArchAttr(Arch),
807                      false);
808   else
809     setAttributeItem(CPU_arch,
810                      ARM::getArchAttr(EmittedArch),
811                      false);
812 
813   switch (Arch) {
814   case ARM::ArchKind::ARMV2:
815   case ARM::ArchKind::ARMV2A:
816   case ARM::ArchKind::ARMV3:
817   case ARM::ArchKind::ARMV3M:
818   case ARM::ArchKind::ARMV4:
819     setAttributeItem(ARM_ISA_use, Allowed, false);
820     break;
821 
822   case ARM::ArchKind::ARMV4T:
823   case ARM::ArchKind::ARMV5T:
824   case ARM::ArchKind::ARMV5TE:
825   case ARM::ArchKind::ARMV6:
826     setAttributeItem(ARM_ISA_use, Allowed, false);
827     setAttributeItem(THUMB_ISA_use, Allowed, false);
828     break;
829 
830   case ARM::ArchKind::ARMV6T2:
831     setAttributeItem(ARM_ISA_use, Allowed, false);
832     setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
833     break;
834 
835   case ARM::ArchKind::ARMV6K:
836   case ARM::ArchKind::ARMV6KZ:
837     setAttributeItem(ARM_ISA_use, Allowed, false);
838     setAttributeItem(THUMB_ISA_use, Allowed, false);
839     setAttributeItem(Virtualization_use, AllowTZ, false);
840     break;
841 
842   case ARM::ArchKind::ARMV6M:
843     setAttributeItem(THUMB_ISA_use, Allowed, false);
844     break;
845 
846   case ARM::ArchKind::ARMV7A:
847     setAttributeItem(CPU_arch_profile, ApplicationProfile, false);
848     setAttributeItem(ARM_ISA_use, Allowed, false);
849     setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
850     break;
851 
852   case ARM::ArchKind::ARMV7R:
853     setAttributeItem(CPU_arch_profile, RealTimeProfile, false);
854     setAttributeItem(ARM_ISA_use, Allowed, false);
855     setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
856     break;
857 
858   case ARM::ArchKind::ARMV7EM:
859   case ARM::ArchKind::ARMV7M:
860     setAttributeItem(CPU_arch_profile, MicroControllerProfile, false);
861     setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
862     break;
863 
864   case ARM::ArchKind::ARMV8A:
865   case ARM::ArchKind::ARMV8_1A:
866   case ARM::ArchKind::ARMV8_2A:
867   case ARM::ArchKind::ARMV8_3A:
868   case ARM::ArchKind::ARMV8_4A:
869   case ARM::ArchKind::ARMV8_5A:
870     setAttributeItem(CPU_arch_profile, ApplicationProfile, false);
871     setAttributeItem(ARM_ISA_use, Allowed, false);
872     setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
873     setAttributeItem(MPextension_use, Allowed, false);
874     setAttributeItem(Virtualization_use, AllowTZVirtualization, false);
875     break;
876 
877   case ARM::ArchKind::ARMV8MBaseline:
878   case ARM::ArchKind::ARMV8MMainline:
879     setAttributeItem(THUMB_ISA_use, AllowThumbDerived, false);
880     setAttributeItem(CPU_arch_profile, MicroControllerProfile, false);
881     break;
882 
883   case ARM::ArchKind::IWMMXT:
884     setAttributeItem(ARM_ISA_use, Allowed, false);
885     setAttributeItem(THUMB_ISA_use, Allowed, false);
886     setAttributeItem(WMMX_arch, AllowWMMXv1, false);
887     break;
888 
889   case ARM::ArchKind::IWMMXT2:
890     setAttributeItem(ARM_ISA_use, Allowed, false);
891     setAttributeItem(THUMB_ISA_use, Allowed, false);
892     setAttributeItem(WMMX_arch, AllowWMMXv2, false);
893     break;
894 
895   default:
896     report_fatal_error("Unknown Arch: " + Twine(ARM::getArchName(Arch)));
897     break;
898   }
899 }
900 
emitFPU(unsigned Value)901 void ARMTargetELFStreamer::emitFPU(unsigned Value) {
902   FPU = Value;
903 }
904 
emitFPUDefaultAttributes()905 void ARMTargetELFStreamer::emitFPUDefaultAttributes() {
906   switch (FPU) {
907   case ARM::FK_VFP:
908   case ARM::FK_VFPV2:
909     setAttributeItem(ARMBuildAttrs::FP_arch,
910                      ARMBuildAttrs::AllowFPv2,
911                      /* OverwriteExisting= */ false);
912     break;
913 
914   case ARM::FK_VFPV3:
915     setAttributeItem(ARMBuildAttrs::FP_arch,
916                      ARMBuildAttrs::AllowFPv3A,
917                      /* OverwriteExisting= */ false);
918     break;
919 
920   case ARM::FK_VFPV3_FP16:
921     setAttributeItem(ARMBuildAttrs::FP_arch,
922                      ARMBuildAttrs::AllowFPv3A,
923                      /* OverwriteExisting= */ false);
924     setAttributeItem(ARMBuildAttrs::FP_HP_extension,
925                      ARMBuildAttrs::AllowHPFP,
926                      /* OverwriteExisting= */ false);
927     break;
928 
929   case ARM::FK_VFPV3_D16:
930     setAttributeItem(ARMBuildAttrs::FP_arch,
931                      ARMBuildAttrs::AllowFPv3B,
932                      /* OverwriteExisting= */ false);
933     break;
934 
935   case ARM::FK_VFPV3_D16_FP16:
936     setAttributeItem(ARMBuildAttrs::FP_arch,
937                      ARMBuildAttrs::AllowFPv3B,
938                      /* OverwriteExisting= */ false);
939     setAttributeItem(ARMBuildAttrs::FP_HP_extension,
940                      ARMBuildAttrs::AllowHPFP,
941                      /* OverwriteExisting= */ false);
942     break;
943 
944   case ARM::FK_VFPV3XD:
945     setAttributeItem(ARMBuildAttrs::FP_arch,
946                      ARMBuildAttrs::AllowFPv3B,
947                      /* OverwriteExisting= */ false);
948     break;
949   case ARM::FK_VFPV3XD_FP16:
950     setAttributeItem(ARMBuildAttrs::FP_arch,
951                      ARMBuildAttrs::AllowFPv3B,
952                      /* OverwriteExisting= */ false);
953     setAttributeItem(ARMBuildAttrs::FP_HP_extension,
954                      ARMBuildAttrs::AllowHPFP,
955                      /* OverwriteExisting= */ false);
956     break;
957 
958   case ARM::FK_VFPV4:
959     setAttributeItem(ARMBuildAttrs::FP_arch,
960                      ARMBuildAttrs::AllowFPv4A,
961                      /* OverwriteExisting= */ false);
962     break;
963 
964   // ABI_HardFP_use is handled in ARMAsmPrinter, so _SP_D16 is treated the same
965   // as _D16 here.
966   case ARM::FK_FPV4_SP_D16:
967   case ARM::FK_VFPV4_D16:
968     setAttributeItem(ARMBuildAttrs::FP_arch,
969                      ARMBuildAttrs::AllowFPv4B,
970                      /* OverwriteExisting= */ false);
971     break;
972 
973   case ARM::FK_FP_ARMV8:
974     setAttributeItem(ARMBuildAttrs::FP_arch,
975                      ARMBuildAttrs::AllowFPARMv8A,
976                      /* OverwriteExisting= */ false);
977     break;
978 
979   // FPV5_D16 is identical to FP_ARMV8 except for the number of D registers, so
980   // uses the FP_ARMV8_D16 build attribute.
981   case ARM::FK_FPV5_SP_D16:
982   case ARM::FK_FPV5_D16:
983     setAttributeItem(ARMBuildAttrs::FP_arch,
984                      ARMBuildAttrs::AllowFPARMv8B,
985                      /* OverwriteExisting= */ false);
986     break;
987 
988   case ARM::FK_NEON:
989     setAttributeItem(ARMBuildAttrs::FP_arch,
990                      ARMBuildAttrs::AllowFPv3A,
991                      /* OverwriteExisting= */ false);
992     setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
993                      ARMBuildAttrs::AllowNeon,
994                      /* OverwriteExisting= */ false);
995     break;
996 
997   case ARM::FK_NEON_FP16:
998     setAttributeItem(ARMBuildAttrs::FP_arch,
999                      ARMBuildAttrs::AllowFPv3A,
1000                      /* OverwriteExisting= */ false);
1001     setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
1002                      ARMBuildAttrs::AllowNeon,
1003                      /* OverwriteExisting= */ false);
1004     setAttributeItem(ARMBuildAttrs::FP_HP_extension,
1005                      ARMBuildAttrs::AllowHPFP,
1006                      /* OverwriteExisting= */ false);
1007     break;
1008 
1009   case ARM::FK_NEON_VFPV4:
1010     setAttributeItem(ARMBuildAttrs::FP_arch,
1011                      ARMBuildAttrs::AllowFPv4A,
1012                      /* OverwriteExisting= */ false);
1013     setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
1014                      ARMBuildAttrs::AllowNeon2,
1015                      /* OverwriteExisting= */ false);
1016     break;
1017 
1018   case ARM::FK_NEON_FP_ARMV8:
1019   case ARM::FK_CRYPTO_NEON_FP_ARMV8:
1020     setAttributeItem(ARMBuildAttrs::FP_arch,
1021                      ARMBuildAttrs::AllowFPARMv8A,
1022                      /* OverwriteExisting= */ false);
1023     // 'Advanced_SIMD_arch' must be emitted not here, but within
1024     // ARMAsmPrinter::emitAttributes(), depending on hasV8Ops() and hasV8_1a()
1025     break;
1026 
1027   case ARM::FK_SOFTVFP:
1028   case ARM::FK_NONE:
1029     break;
1030 
1031   default:
1032     report_fatal_error("Unknown FPU: " + Twine(FPU));
1033     break;
1034   }
1035 }
1036 
calculateContentSize() const1037 size_t ARMTargetELFStreamer::calculateContentSize() const {
1038   size_t Result = 0;
1039   for (size_t i = 0; i < Contents.size(); ++i) {
1040     AttributeItem item = Contents[i];
1041     switch (item.Type) {
1042     case AttributeItem::HiddenAttribute:
1043       break;
1044     case AttributeItem::NumericAttribute:
1045       Result += getULEB128Size(item.Tag);
1046       Result += getULEB128Size(item.IntValue);
1047       break;
1048     case AttributeItem::TextAttribute:
1049       Result += getULEB128Size(item.Tag);
1050       Result += item.StringValue.size() + 1; // string + '\0'
1051       break;
1052     case AttributeItem::NumericAndTextAttributes:
1053       Result += getULEB128Size(item.Tag);
1054       Result += getULEB128Size(item.IntValue);
1055       Result += item.StringValue.size() + 1; // string + '\0';
1056       break;
1057     }
1058   }
1059   return Result;
1060 }
1061 
finishAttributeSection()1062 void ARMTargetELFStreamer::finishAttributeSection() {
1063   // <format-version>
1064   // [ <section-length> "vendor-name"
1065   // [ <file-tag> <size> <attribute>*
1066   //   | <section-tag> <size> <section-number>* 0 <attribute>*
1067   //   | <symbol-tag> <size> <symbol-number>* 0 <attribute>*
1068   //   ]+
1069   // ]*
1070 
1071   if (FPU != ARM::FK_INVALID)
1072     emitFPUDefaultAttributes();
1073 
1074   if (Arch != ARM::ArchKind::INVALID)
1075     emitArchDefaultAttributes();
1076 
1077   if (Contents.empty())
1078     return;
1079 
1080   llvm::sort(Contents, AttributeItem::LessTag);
1081 
1082   ARMELFStreamer &Streamer = getStreamer();
1083 
1084   // Switch to .ARM.attributes section
1085   if (AttributeSection) {
1086     Streamer.SwitchSection(AttributeSection);
1087   } else {
1088     AttributeSection = Streamer.getContext().getELFSection(
1089         ".ARM.attributes", ELF::SHT_ARM_ATTRIBUTES, 0);
1090     Streamer.SwitchSection(AttributeSection);
1091 
1092     // Format version
1093     Streamer.EmitIntValue(0x41, 1);
1094   }
1095 
1096   // Vendor size + Vendor name + '\0'
1097   const size_t VendorHeaderSize = 4 + CurrentVendor.size() + 1;
1098 
1099   // Tag + Tag Size
1100   const size_t TagHeaderSize = 1 + 4;
1101 
1102   const size_t ContentsSize = calculateContentSize();
1103 
1104   Streamer.EmitIntValue(VendorHeaderSize + TagHeaderSize + ContentsSize, 4);
1105   Streamer.EmitBytes(CurrentVendor);
1106   Streamer.EmitIntValue(0, 1); // '\0'
1107 
1108   Streamer.EmitIntValue(ARMBuildAttrs::File, 1);
1109   Streamer.EmitIntValue(TagHeaderSize + ContentsSize, 4);
1110 
1111   // Size should have been accounted for already, now
1112   // emit each field as its type (ULEB or String)
1113   for (size_t i = 0; i < Contents.size(); ++i) {
1114     AttributeItem item = Contents[i];
1115     Streamer.EmitULEB128IntValue(item.Tag);
1116     switch (item.Type) {
1117     default: llvm_unreachable("Invalid attribute type");
1118     case AttributeItem::NumericAttribute:
1119       Streamer.EmitULEB128IntValue(item.IntValue);
1120       break;
1121     case AttributeItem::TextAttribute:
1122       Streamer.EmitBytes(item.StringValue);
1123       Streamer.EmitIntValue(0, 1); // '\0'
1124       break;
1125     case AttributeItem::NumericAndTextAttributes:
1126       Streamer.EmitULEB128IntValue(item.IntValue);
1127       Streamer.EmitBytes(item.StringValue);
1128       Streamer.EmitIntValue(0, 1); // '\0'
1129       break;
1130     }
1131   }
1132 
1133   Contents.clear();
1134   FPU = ARM::FK_INVALID;
1135 }
1136 
emitLabel(MCSymbol * Symbol)1137 void ARMTargetELFStreamer::emitLabel(MCSymbol *Symbol) {
1138   ARMELFStreamer &Streamer = getStreamer();
1139   if (!Streamer.IsThumb)
1140     return;
1141 
1142   Streamer.getAssembler().registerSymbol(*Symbol);
1143   unsigned Type = cast<MCSymbolELF>(Symbol)->getType();
1144   if (Type == ELF::STT_FUNC || Type == ELF::STT_GNU_IFUNC)
1145     Streamer.EmitThumbFunc(Symbol);
1146 }
1147 
1148 void
AnnotateTLSDescriptorSequence(const MCSymbolRefExpr * S)1149 ARMTargetELFStreamer::AnnotateTLSDescriptorSequence(const MCSymbolRefExpr *S) {
1150   getStreamer().EmitFixup(S, FK_Data_4);
1151 }
1152 
emitThumbSet(MCSymbol * Symbol,const MCExpr * Value)1153 void ARMTargetELFStreamer::emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) {
1154   if (const MCSymbolRefExpr *SRE = dyn_cast<MCSymbolRefExpr>(Value)) {
1155     const MCSymbol &Sym = SRE->getSymbol();
1156     if (!Sym.isDefined()) {
1157       getStreamer().EmitAssignment(Symbol, Value);
1158       return;
1159     }
1160   }
1161 
1162   getStreamer().EmitThumbFunc(Symbol);
1163   getStreamer().EmitAssignment(Symbol, Value);
1164 }
1165 
emitInst(uint32_t Inst,char Suffix)1166 void ARMTargetELFStreamer::emitInst(uint32_t Inst, char Suffix) {
1167   getStreamer().emitInst(Inst, Suffix);
1168 }
1169 
reset()1170 void ARMTargetELFStreamer::reset() { AttributeSection = nullptr; }
1171 
FinishImpl()1172 void ARMELFStreamer::FinishImpl() {
1173   MCTargetStreamer &TS = *getTargetStreamer();
1174   ARMTargetStreamer &ATS = static_cast<ARMTargetStreamer &>(TS);
1175   ATS.finishAttributeSection();
1176 
1177   MCELFStreamer::FinishImpl();
1178 }
1179 
reset()1180 void ARMELFStreamer::reset() {
1181   MCTargetStreamer &TS = *getTargetStreamer();
1182   ARMTargetStreamer &ATS = static_cast<ARMTargetStreamer &>(TS);
1183   ATS.reset();
1184   MappingSymbolCounter = 0;
1185   MCELFStreamer::reset();
1186   LastMappingSymbols.clear();
1187   LastEMSInfo.reset();
1188   // MCELFStreamer clear's the assembler's e_flags. However, for
1189   // arm we manually set the ABI version on streamer creation, so
1190   // do the same here
1191   getAssembler().setELFHeaderEFlags(ELF::EF_ARM_EABI_VER5);
1192 }
1193 
SwitchToEHSection(StringRef Prefix,unsigned Type,unsigned Flags,SectionKind Kind,const MCSymbol & Fn)1194 inline void ARMELFStreamer::SwitchToEHSection(StringRef Prefix,
1195                                               unsigned Type,
1196                                               unsigned Flags,
1197                                               SectionKind Kind,
1198                                               const MCSymbol &Fn) {
1199   const MCSectionELF &FnSection =
1200     static_cast<const MCSectionELF &>(Fn.getSection());
1201 
1202   // Create the name for new section
1203   StringRef FnSecName(FnSection.getSectionName());
1204   SmallString<128> EHSecName(Prefix);
1205   if (FnSecName != ".text") {
1206     EHSecName += FnSecName;
1207   }
1208 
1209   // Get .ARM.extab or .ARM.exidx section
1210   const MCSymbolELF *Group = FnSection.getGroup();
1211   if (Group)
1212     Flags |= ELF::SHF_GROUP;
1213   MCSectionELF *EHSection = getContext().getELFSection(
1214       EHSecName, Type, Flags, 0, Group, FnSection.getUniqueID(),
1215       static_cast<const MCSymbolELF *>(&Fn));
1216 
1217   assert(EHSection && "Failed to get the required EH section");
1218 
1219   // Switch to .ARM.extab or .ARM.exidx section
1220   SwitchSection(EHSection);
1221   EmitCodeAlignment(4);
1222 }
1223 
SwitchToExTabSection(const MCSymbol & FnStart)1224 inline void ARMELFStreamer::SwitchToExTabSection(const MCSymbol &FnStart) {
1225   SwitchToEHSection(".ARM.extab", ELF::SHT_PROGBITS, ELF::SHF_ALLOC,
1226                     SectionKind::getData(), FnStart);
1227 }
1228 
SwitchToExIdxSection(const MCSymbol & FnStart)1229 inline void ARMELFStreamer::SwitchToExIdxSection(const MCSymbol &FnStart) {
1230   SwitchToEHSection(".ARM.exidx", ELF::SHT_ARM_EXIDX,
1231                     ELF::SHF_ALLOC | ELF::SHF_LINK_ORDER,
1232                     SectionKind::getData(), FnStart);
1233 }
1234 
EmitFixup(const MCExpr * Expr,MCFixupKind Kind)1235 void ARMELFStreamer::EmitFixup(const MCExpr *Expr, MCFixupKind Kind) {
1236   MCDataFragment *Frag = getOrCreateDataFragment();
1237   Frag->getFixups().push_back(MCFixup::create(Frag->getContents().size(), Expr,
1238                                               Kind));
1239 }
1240 
EHReset()1241 void ARMELFStreamer::EHReset() {
1242   ExTab = nullptr;
1243   FnStart = nullptr;
1244   Personality = nullptr;
1245   PersonalityIndex = ARM::EHABI::NUM_PERSONALITY_INDEX;
1246   FPReg = ARM::SP;
1247   FPOffset = 0;
1248   SPOffset = 0;
1249   PendingOffset = 0;
1250   UsedFP = false;
1251   CantUnwind = false;
1252 
1253   Opcodes.clear();
1254   UnwindOpAsm.Reset();
1255 }
1256 
emitFnStart()1257 void ARMELFStreamer::emitFnStart() {
1258   assert(FnStart == nullptr);
1259   FnStart = getContext().createTempSymbol();
1260   EmitLabel(FnStart);
1261 }
1262 
emitFnEnd()1263 void ARMELFStreamer::emitFnEnd() {
1264   assert(FnStart && ".fnstart must precedes .fnend");
1265 
1266   // Emit unwind opcodes if there is no .handlerdata directive
1267   if (!ExTab && !CantUnwind)
1268     FlushUnwindOpcodes(true);
1269 
1270   // Emit the exception index table entry
1271   SwitchToExIdxSection(*FnStart);
1272 
1273   if (PersonalityIndex < ARM::EHABI::NUM_PERSONALITY_INDEX)
1274     EmitPersonalityFixup(GetAEABIUnwindPersonalityName(PersonalityIndex));
1275 
1276   const MCSymbolRefExpr *FnStartRef =
1277     MCSymbolRefExpr::create(FnStart,
1278                             MCSymbolRefExpr::VK_ARM_PREL31,
1279                             getContext());
1280 
1281   EmitValue(FnStartRef, 4);
1282 
1283   if (CantUnwind) {
1284     EmitIntValue(ARM::EHABI::EXIDX_CANTUNWIND, 4);
1285   } else if (ExTab) {
1286     // Emit a reference to the unwind opcodes in the ".ARM.extab" section.
1287     const MCSymbolRefExpr *ExTabEntryRef =
1288       MCSymbolRefExpr::create(ExTab,
1289                               MCSymbolRefExpr::VK_ARM_PREL31,
1290                               getContext());
1291     EmitValue(ExTabEntryRef, 4);
1292   } else {
1293     // For the __aeabi_unwind_cpp_pr0, we have to emit the unwind opcodes in
1294     // the second word of exception index table entry.  The size of the unwind
1295     // opcodes should always be 4 bytes.
1296     assert(PersonalityIndex == ARM::EHABI::AEABI_UNWIND_CPP_PR0 &&
1297            "Compact model must use __aeabi_unwind_cpp_pr0 as personality");
1298     assert(Opcodes.size() == 4u &&
1299            "Unwind opcode size for __aeabi_unwind_cpp_pr0 must be equal to 4");
1300     uint64_t Intval = Opcodes[0] |
1301                       Opcodes[1] << 8 |
1302                       Opcodes[2] << 16 |
1303                       Opcodes[3] << 24;
1304     EmitIntValue(Intval, Opcodes.size());
1305   }
1306 
1307   // Switch to the section containing FnStart
1308   SwitchSection(&FnStart->getSection());
1309 
1310   // Clean exception handling frame information
1311   EHReset();
1312 }
1313 
emitCantUnwind()1314 void ARMELFStreamer::emitCantUnwind() { CantUnwind = true; }
1315 
1316 // Add the R_ARM_NONE fixup at the same position
EmitPersonalityFixup(StringRef Name)1317 void ARMELFStreamer::EmitPersonalityFixup(StringRef Name) {
1318   const MCSymbol *PersonalitySym = getContext().getOrCreateSymbol(Name);
1319 
1320   const MCSymbolRefExpr *PersonalityRef = MCSymbolRefExpr::create(
1321       PersonalitySym, MCSymbolRefExpr::VK_ARM_NONE, getContext());
1322 
1323   visitUsedExpr(*PersonalityRef);
1324   MCDataFragment *DF = getOrCreateDataFragment();
1325   DF->getFixups().push_back(MCFixup::create(DF->getContents().size(),
1326                                             PersonalityRef,
1327                                             MCFixup::getKindForSize(4, false)));
1328 }
1329 
FlushPendingOffset()1330 void ARMELFStreamer::FlushPendingOffset() {
1331   if (PendingOffset != 0) {
1332     UnwindOpAsm.EmitSPOffset(-PendingOffset);
1333     PendingOffset = 0;
1334   }
1335 }
1336 
FlushUnwindOpcodes(bool NoHandlerData)1337 void ARMELFStreamer::FlushUnwindOpcodes(bool NoHandlerData) {
1338   // Emit the unwind opcode to restore $sp.
1339   if (UsedFP) {
1340     const MCRegisterInfo *MRI = getContext().getRegisterInfo();
1341     int64_t LastRegSaveSPOffset = SPOffset - PendingOffset;
1342     UnwindOpAsm.EmitSPOffset(LastRegSaveSPOffset - FPOffset);
1343     UnwindOpAsm.EmitSetSP(MRI->getEncodingValue(FPReg));
1344   } else {
1345     FlushPendingOffset();
1346   }
1347 
1348   // Finalize the unwind opcode sequence
1349   UnwindOpAsm.Finalize(PersonalityIndex, Opcodes);
1350 
1351   // For compact model 0, we have to emit the unwind opcodes in the .ARM.exidx
1352   // section.  Thus, we don't have to create an entry in the .ARM.extab
1353   // section.
1354   if (NoHandlerData && PersonalityIndex == ARM::EHABI::AEABI_UNWIND_CPP_PR0)
1355     return;
1356 
1357   // Switch to .ARM.extab section.
1358   SwitchToExTabSection(*FnStart);
1359 
1360   // Create .ARM.extab label for offset in .ARM.exidx
1361   assert(!ExTab);
1362   ExTab = getContext().createTempSymbol();
1363   EmitLabel(ExTab);
1364 
1365   // Emit personality
1366   if (Personality) {
1367     const MCSymbolRefExpr *PersonalityRef =
1368       MCSymbolRefExpr::create(Personality,
1369                               MCSymbolRefExpr::VK_ARM_PREL31,
1370                               getContext());
1371 
1372     EmitValue(PersonalityRef, 4);
1373   }
1374 
1375   // Emit unwind opcodes
1376   assert((Opcodes.size() % 4) == 0 &&
1377          "Unwind opcode size for __aeabi_cpp_unwind_pr0 must be multiple of 4");
1378   for (unsigned I = 0; I != Opcodes.size(); I += 4) {
1379     uint64_t Intval = Opcodes[I] |
1380                       Opcodes[I + 1] << 8 |
1381                       Opcodes[I + 2] << 16 |
1382                       Opcodes[I + 3] << 24;
1383     EmitIntValue(Intval, 4);
1384   }
1385 
1386   // According to ARM EHABI section 9.2, if the __aeabi_unwind_cpp_pr1() or
1387   // __aeabi_unwind_cpp_pr2() is used, then the handler data must be emitted
1388   // after the unwind opcodes.  The handler data consists of several 32-bit
1389   // words, and should be terminated by zero.
1390   //
1391   // In case that the .handlerdata directive is not specified by the
1392   // programmer, we should emit zero to terminate the handler data.
1393   if (NoHandlerData && !Personality)
1394     EmitIntValue(0, 4);
1395 }
1396 
emitHandlerData()1397 void ARMELFStreamer::emitHandlerData() { FlushUnwindOpcodes(false); }
1398 
emitPersonality(const MCSymbol * Per)1399 void ARMELFStreamer::emitPersonality(const MCSymbol *Per) {
1400   Personality = Per;
1401   UnwindOpAsm.setPersonality(Per);
1402 }
1403 
emitPersonalityIndex(unsigned Index)1404 void ARMELFStreamer::emitPersonalityIndex(unsigned Index) {
1405   assert(Index < ARM::EHABI::NUM_PERSONALITY_INDEX && "invalid index");
1406   PersonalityIndex = Index;
1407 }
1408 
emitSetFP(unsigned NewFPReg,unsigned NewSPReg,int64_t Offset)1409 void ARMELFStreamer::emitSetFP(unsigned NewFPReg, unsigned NewSPReg,
1410                                int64_t Offset) {
1411   assert((NewSPReg == ARM::SP || NewSPReg == FPReg) &&
1412          "the operand of .setfp directive should be either $sp or $fp");
1413 
1414   UsedFP = true;
1415   FPReg = NewFPReg;
1416 
1417   if (NewSPReg == ARM::SP)
1418     FPOffset = SPOffset + Offset;
1419   else
1420     FPOffset += Offset;
1421 }
1422 
emitMovSP(unsigned Reg,int64_t Offset)1423 void ARMELFStreamer::emitMovSP(unsigned Reg, int64_t Offset) {
1424   assert((Reg != ARM::SP && Reg != ARM::PC) &&
1425          "the operand of .movsp cannot be either sp or pc");
1426   assert(FPReg == ARM::SP && "current FP must be SP");
1427 
1428   FlushPendingOffset();
1429 
1430   FPReg = Reg;
1431   FPOffset = SPOffset + Offset;
1432 
1433   const MCRegisterInfo *MRI = getContext().getRegisterInfo();
1434   UnwindOpAsm.EmitSetSP(MRI->getEncodingValue(FPReg));
1435 }
1436 
emitPad(int64_t Offset)1437 void ARMELFStreamer::emitPad(int64_t Offset) {
1438   // Track the change of the $sp offset
1439   SPOffset -= Offset;
1440 
1441   // To squash multiple .pad directives, we should delay the unwind opcode
1442   // until the .save, .vsave, .handlerdata, or .fnend directives.
1443   PendingOffset -= Offset;
1444 }
1445 
emitRegSave(const SmallVectorImpl<unsigned> & RegList,bool IsVector)1446 void ARMELFStreamer::emitRegSave(const SmallVectorImpl<unsigned> &RegList,
1447                                  bool IsVector) {
1448   // Collect the registers in the register list
1449   unsigned Count = 0;
1450   uint32_t Mask = 0;
1451   const MCRegisterInfo *MRI = getContext().getRegisterInfo();
1452   for (size_t i = 0; i < RegList.size(); ++i) {
1453     unsigned Reg = MRI->getEncodingValue(RegList[i]);
1454     assert(Reg < (IsVector ? 32U : 16U) && "Register out of range");
1455     unsigned Bit = (1u << Reg);
1456     if ((Mask & Bit) == 0) {
1457       Mask |= Bit;
1458       ++Count;
1459     }
1460   }
1461 
1462   // Track the change the $sp offset: For the .save directive, the
1463   // corresponding push instruction will decrease the $sp by (4 * Count).
1464   // For the .vsave directive, the corresponding vpush instruction will
1465   // decrease $sp by (8 * Count).
1466   SPOffset -= Count * (IsVector ? 8 : 4);
1467 
1468   // Emit the opcode
1469   FlushPendingOffset();
1470   if (IsVector)
1471     UnwindOpAsm.EmitVFPRegSave(Mask);
1472   else
1473     UnwindOpAsm.EmitRegSave(Mask);
1474 }
1475 
emitUnwindRaw(int64_t Offset,const SmallVectorImpl<uint8_t> & Opcodes)1476 void ARMELFStreamer::emitUnwindRaw(int64_t Offset,
1477                                    const SmallVectorImpl<uint8_t> &Opcodes) {
1478   FlushPendingOffset();
1479   SPOffset = SPOffset - Offset;
1480   UnwindOpAsm.EmitRaw(Opcodes);
1481 }
1482 
1483 namespace llvm {
1484 
createARMTargetAsmStreamer(MCStreamer & S,formatted_raw_ostream & OS,MCInstPrinter * InstPrint,bool isVerboseAsm)1485 MCTargetStreamer *createARMTargetAsmStreamer(MCStreamer &S,
1486                                              formatted_raw_ostream &OS,
1487                                              MCInstPrinter *InstPrint,
1488                                              bool isVerboseAsm) {
1489   return new ARMTargetAsmStreamer(S, OS, *InstPrint, isVerboseAsm);
1490 }
1491 
createARMNullTargetStreamer(MCStreamer & S)1492 MCTargetStreamer *createARMNullTargetStreamer(MCStreamer &S) {
1493   return new ARMTargetStreamer(S);
1494 }
1495 
createARMObjectTargetStreamer(MCStreamer & S,const MCSubtargetInfo & STI)1496 MCTargetStreamer *createARMObjectTargetStreamer(MCStreamer &S,
1497                                                 const MCSubtargetInfo &STI) {
1498   const Triple &TT = STI.getTargetTriple();
1499   if (TT.isOSBinFormatELF())
1500     return new ARMTargetELFStreamer(S);
1501   return new ARMTargetStreamer(S);
1502 }
1503 
createARMELFStreamer(MCContext & Context,std::unique_ptr<MCAsmBackend> TAB,std::unique_ptr<MCObjectWriter> OW,std::unique_ptr<MCCodeEmitter> Emitter,bool RelaxAll,bool IsThumb)1504 MCELFStreamer *createARMELFStreamer(MCContext &Context,
1505                                     std::unique_ptr<MCAsmBackend> TAB,
1506                                     std::unique_ptr<MCObjectWriter> OW,
1507                                     std::unique_ptr<MCCodeEmitter> Emitter,
1508                                     bool RelaxAll, bool IsThumb) {
1509   ARMELFStreamer *S = new ARMELFStreamer(Context, std::move(TAB), std::move(OW),
1510                                          std::move(Emitter), IsThumb);
1511   // FIXME: This should eventually end up somewhere else where more
1512   // intelligent flag decisions can be made. For now we are just maintaining
1513   // the status quo for ARM and setting EF_ARM_EABI_VER5 as the default.
1514   S->getAssembler().setELFHeaderEFlags(ELF::EF_ARM_EABI_VER5);
1515 
1516   if (RelaxAll)
1517     S->getAssembler().setRelaxAll(true);
1518   return S;
1519 }
1520 
1521 } // end namespace llvm
1522