1 //===- lib/MC/ARMELFStreamer.cpp - ELF Object Output for ARM --------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file assembles .s files and emits ARM ELF .o object files. Different
10 // from generic ELF streamer in emitting mapping symbols ($a, $t and $d) to
11 // delimit regions of data and code.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #include "ARMRegisterInfo.h"
16 #include "ARMUnwindOpAsm.h"
17 #include "llvm/ADT/DenseMap.h"
18 #include "llvm/ADT/SmallString.h"
19 #include "llvm/ADT/SmallVector.h"
20 #include "llvm/ADT/StringExtras.h"
21 #include "llvm/ADT/StringRef.h"
22 #include "llvm/ADT/Twine.h"
23 #include "llvm/BinaryFormat/ELF.h"
24 #include "llvm/MC/MCAsmBackend.h"
25 #include "llvm/MC/MCAsmInfo.h"
26 #include "llvm/MC/MCAssembler.h"
27 #include "llvm/MC/MCCodeEmitter.h"
28 #include "llvm/MC/MCContext.h"
29 #include "llvm/MC/MCELFStreamer.h"
30 #include "llvm/MC/MCExpr.h"
31 #include "llvm/MC/MCFixup.h"
32 #include "llvm/MC/MCFragment.h"
33 #include "llvm/MC/MCInst.h"
34 #include "llvm/MC/MCInstPrinter.h"
35 #include "llvm/MC/MCObjectWriter.h"
36 #include "llvm/MC/MCRegisterInfo.h"
37 #include "llvm/MC/MCSection.h"
38 #include "llvm/MC/MCSectionELF.h"
39 #include "llvm/MC/MCStreamer.h"
40 #include "llvm/MC/MCSubtargetInfo.h"
41 #include "llvm/MC/MCSymbol.h"
42 #include "llvm/MC/MCSymbolELF.h"
43 #include "llvm/MC/SectionKind.h"
44 #include "llvm/Support/ARMBuildAttributes.h"
45 #include "llvm/Support/ARMEHABI.h"
46 #include "llvm/Support/Casting.h"
47 #include "llvm/Support/ErrorHandling.h"
48 #include "llvm/Support/FormattedStream.h"
49 #include "llvm/Support/TargetParser.h"
50 #include "llvm/Support/raw_ostream.h"
51 #include <algorithm>
52 #include <cassert>
53 #include <climits>
54 #include <cstddef>
55 #include <cstdint>
56 #include <string>
57 
58 using namespace llvm;
59 
GetAEABIUnwindPersonalityName(unsigned Index)60 static std::string GetAEABIUnwindPersonalityName(unsigned Index) {
61   assert(Index < ARM::EHABI::NUM_PERSONALITY_INDEX &&
62          "Invalid personality index");
63   return (Twine("__aeabi_unwind_cpp_pr") + Twine(Index)).str();
64 }
65 
66 namespace {
67 
68 class ARMELFStreamer;
69 
70 class ARMTargetAsmStreamer : public ARMTargetStreamer {
71   formatted_raw_ostream &OS;
72   MCInstPrinter &InstPrinter;
73   bool IsVerboseAsm;
74 
75   void emitFnStart() override;
76   void emitFnEnd() override;
77   void emitCantUnwind() override;
78   void emitPersonality(const MCSymbol *Personality) override;
79   void emitPersonalityIndex(unsigned Index) override;
80   void emitHandlerData() override;
81   void emitSetFP(unsigned FpReg, unsigned SpReg, int64_t Offset = 0) override;
82   void emitMovSP(unsigned Reg, int64_t Offset = 0) override;
83   void emitPad(int64_t Offset) override;
84   void emitRegSave(const SmallVectorImpl<unsigned> &RegList,
85                    bool isVector) override;
86   void emitUnwindRaw(int64_t Offset,
87                      const SmallVectorImpl<uint8_t> &Opcodes) override;
88 
89   void switchVendor(StringRef Vendor) override;
90   void emitAttribute(unsigned Attribute, unsigned Value) override;
91   void emitTextAttribute(unsigned Attribute, StringRef String) override;
92   void emitIntTextAttribute(unsigned Attribute, unsigned IntValue,
93                             StringRef StringValue) override;
94   void emitArch(ARM::ArchKind Arch) override;
95   void emitArchExtension(uint64_t ArchExt) override;
96   void emitObjectArch(ARM::ArchKind Arch) override;
97   void emitFPU(unsigned FPU) override;
98   void emitInst(uint32_t Inst, char Suffix = '\0') override;
99   void finishAttributeSection() override;
100 
101   void annotateTLSDescriptorSequence(const MCSymbolRefExpr *SRE) override;
102   void emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) override;
103 
104   void emitARMWinCFIAllocStack(unsigned Size, bool Wide) override;
105   void emitARMWinCFISaveRegMask(unsigned Mask, bool Wide) override;
106   void emitARMWinCFISaveSP(unsigned Reg) override;
107   void emitARMWinCFISaveFRegs(unsigned First, unsigned Last) override;
108   void emitARMWinCFISaveLR(unsigned Offset) override;
109   void emitARMWinCFIPrologEnd(bool Fragment) override;
110   void emitARMWinCFINop(bool Wide) override;
111   void emitARMWinCFIEpilogStart(unsigned Condition) override;
112   void emitARMWinCFIEpilogEnd() override;
113   void emitARMWinCFICustom(unsigned Opcode) override;
114 
115 public:
116   ARMTargetAsmStreamer(MCStreamer &S, formatted_raw_ostream &OS,
117                        MCInstPrinter &InstPrinter, bool VerboseAsm);
118 };
119 
ARMTargetAsmStreamer(MCStreamer & S,formatted_raw_ostream & OS,MCInstPrinter & InstPrinter,bool VerboseAsm)120 ARMTargetAsmStreamer::ARMTargetAsmStreamer(MCStreamer &S,
121                                            formatted_raw_ostream &OS,
122                                            MCInstPrinter &InstPrinter,
123                                            bool VerboseAsm)
124     : ARMTargetStreamer(S), OS(OS), InstPrinter(InstPrinter),
125       IsVerboseAsm(VerboseAsm) {}
126 
emitFnStart()127 void ARMTargetAsmStreamer::emitFnStart() { OS << "\t.fnstart\n"; }
emitFnEnd()128 void ARMTargetAsmStreamer::emitFnEnd() { OS << "\t.fnend\n"; }
emitCantUnwind()129 void ARMTargetAsmStreamer::emitCantUnwind() { OS << "\t.cantunwind\n"; }
130 
emitPersonality(const MCSymbol * Personality)131 void ARMTargetAsmStreamer::emitPersonality(const MCSymbol *Personality) {
132   OS << "\t.personality " << Personality->getName() << '\n';
133 }
134 
emitPersonalityIndex(unsigned Index)135 void ARMTargetAsmStreamer::emitPersonalityIndex(unsigned Index) {
136   OS << "\t.personalityindex " << Index << '\n';
137 }
138 
emitHandlerData()139 void ARMTargetAsmStreamer::emitHandlerData() { OS << "\t.handlerdata\n"; }
140 
emitSetFP(unsigned FpReg,unsigned SpReg,int64_t Offset)141 void ARMTargetAsmStreamer::emitSetFP(unsigned FpReg, unsigned SpReg,
142                                      int64_t Offset) {
143   OS << "\t.setfp\t";
144   InstPrinter.printRegName(OS, FpReg);
145   OS << ", ";
146   InstPrinter.printRegName(OS, SpReg);
147   if (Offset)
148     OS << ", #" << Offset;
149   OS << '\n';
150 }
151 
emitMovSP(unsigned Reg,int64_t Offset)152 void ARMTargetAsmStreamer::emitMovSP(unsigned Reg, int64_t Offset) {
153   assert((Reg != ARM::SP && Reg != ARM::PC) &&
154          "the operand of .movsp cannot be either sp or pc");
155 
156   OS << "\t.movsp\t";
157   InstPrinter.printRegName(OS, Reg);
158   if (Offset)
159     OS << ", #" << Offset;
160   OS << '\n';
161 }
162 
emitPad(int64_t Offset)163 void ARMTargetAsmStreamer::emitPad(int64_t Offset) {
164   OS << "\t.pad\t#" << Offset << '\n';
165 }
166 
emitRegSave(const SmallVectorImpl<unsigned> & RegList,bool isVector)167 void ARMTargetAsmStreamer::emitRegSave(const SmallVectorImpl<unsigned> &RegList,
168                                        bool isVector) {
169   assert(RegList.size() && "RegList should not be empty");
170   if (isVector)
171     OS << "\t.vsave\t{";
172   else
173     OS << "\t.save\t{";
174 
175   InstPrinter.printRegName(OS, RegList[0]);
176 
177   for (unsigned i = 1, e = RegList.size(); i != e; ++i) {
178     OS << ", ";
179     InstPrinter.printRegName(OS, RegList[i]);
180   }
181 
182   OS << "}\n";
183 }
184 
switchVendor(StringRef Vendor)185 void ARMTargetAsmStreamer::switchVendor(StringRef Vendor) {}
186 
emitAttribute(unsigned Attribute,unsigned Value)187 void ARMTargetAsmStreamer::emitAttribute(unsigned Attribute, unsigned Value) {
188   OS << "\t.eabi_attribute\t" << Attribute << ", " << Twine(Value);
189   if (IsVerboseAsm) {
190     StringRef Name = ELFAttrs::attrTypeAsString(
191         Attribute, ARMBuildAttrs::getARMAttributeTags());
192     if (!Name.empty())
193       OS << "\t@ " << Name;
194   }
195   OS << "\n";
196 }
197 
emitTextAttribute(unsigned Attribute,StringRef String)198 void ARMTargetAsmStreamer::emitTextAttribute(unsigned Attribute,
199                                              StringRef String) {
200   switch (Attribute) {
201   case ARMBuildAttrs::CPU_name:
202     OS << "\t.cpu\t" << String.lower();
203     break;
204   default:
205     OS << "\t.eabi_attribute\t" << Attribute << ", \"";
206     if (Attribute == ARMBuildAttrs::also_compatible_with)
207       OS.write_escaped(String);
208     else
209       OS << String;
210     OS << "\"";
211     if (IsVerboseAsm) {
212       StringRef Name = ELFAttrs::attrTypeAsString(
213           Attribute, ARMBuildAttrs::getARMAttributeTags());
214       if (!Name.empty())
215         OS << "\t@ " << Name;
216     }
217     break;
218   }
219   OS << "\n";
220 }
221 
emitIntTextAttribute(unsigned Attribute,unsigned IntValue,StringRef StringValue)222 void ARMTargetAsmStreamer::emitIntTextAttribute(unsigned Attribute,
223                                                 unsigned IntValue,
224                                                 StringRef StringValue) {
225   switch (Attribute) {
226   default: llvm_unreachable("unsupported multi-value attribute in asm mode");
227   case ARMBuildAttrs::compatibility:
228     OS << "\t.eabi_attribute\t" << Attribute << ", " << IntValue;
229     if (!StringValue.empty())
230       OS << ", \"" << StringValue << "\"";
231     if (IsVerboseAsm)
232       OS << "\t@ "
233          << ELFAttrs::attrTypeAsString(Attribute,
234                                        ARMBuildAttrs::getARMAttributeTags());
235     break;
236   }
237   OS << "\n";
238 }
239 
emitArch(ARM::ArchKind Arch)240 void ARMTargetAsmStreamer::emitArch(ARM::ArchKind Arch) {
241   OS << "\t.arch\t" << ARM::getArchName(Arch) << "\n";
242 }
243 
emitArchExtension(uint64_t ArchExt)244 void ARMTargetAsmStreamer::emitArchExtension(uint64_t ArchExt) {
245   OS << "\t.arch_extension\t" << ARM::getArchExtName(ArchExt) << "\n";
246 }
247 
emitObjectArch(ARM::ArchKind Arch)248 void ARMTargetAsmStreamer::emitObjectArch(ARM::ArchKind Arch) {
249   OS << "\t.object_arch\t" << ARM::getArchName(Arch) << '\n';
250 }
251 
emitFPU(unsigned FPU)252 void ARMTargetAsmStreamer::emitFPU(unsigned FPU) {
253   OS << "\t.fpu\t" << ARM::getFPUName(FPU) << "\n";
254 }
255 
finishAttributeSection()256 void ARMTargetAsmStreamer::finishAttributeSection() {}
257 
annotateTLSDescriptorSequence(const MCSymbolRefExpr * S)258 void ARMTargetAsmStreamer::annotateTLSDescriptorSequence(
259     const MCSymbolRefExpr *S) {
260   OS << "\t.tlsdescseq\t" << S->getSymbol().getName() << "\n";
261 }
262 
emitThumbSet(MCSymbol * Symbol,const MCExpr * Value)263 void ARMTargetAsmStreamer::emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) {
264   const MCAsmInfo *MAI = Streamer.getContext().getAsmInfo();
265 
266   OS << "\t.thumb_set\t";
267   Symbol->print(OS, MAI);
268   OS << ", ";
269   Value->print(OS, MAI);
270   OS << '\n';
271 }
272 
emitInst(uint32_t Inst,char Suffix)273 void ARMTargetAsmStreamer::emitInst(uint32_t Inst, char Suffix) {
274   OS << "\t.inst";
275   if (Suffix)
276     OS << "." << Suffix;
277   OS << "\t0x" << Twine::utohexstr(Inst) << "\n";
278 }
279 
emitUnwindRaw(int64_t Offset,const SmallVectorImpl<uint8_t> & Opcodes)280 void ARMTargetAsmStreamer::emitUnwindRaw(int64_t Offset,
281                                       const SmallVectorImpl<uint8_t> &Opcodes) {
282   OS << "\t.unwind_raw " << Offset;
283   for (uint8_t Opcode : Opcodes)
284     OS << ", 0x" << Twine::utohexstr(Opcode);
285   OS << '\n';
286 }
287 
emitARMWinCFIAllocStack(unsigned Size,bool Wide)288 void ARMTargetAsmStreamer::emitARMWinCFIAllocStack(unsigned Size, bool Wide) {
289   if (Wide)
290     OS << "\t.seh_stackalloc_w\t" << Size << "\n";
291   else
292     OS << "\t.seh_stackalloc\t" << Size << "\n";
293 }
294 
printRegs(formatted_raw_ostream & OS,ListSeparator & LS,int First,int Last)295 static void printRegs(formatted_raw_ostream &OS, ListSeparator &LS, int First,
296                       int Last) {
297   if (First != Last)
298     OS << LS << "r" << First << "-r" << Last;
299   else
300     OS << LS << "r" << First;
301 }
302 
emitARMWinCFISaveRegMask(unsigned Mask,bool Wide)303 void ARMTargetAsmStreamer::emitARMWinCFISaveRegMask(unsigned Mask, bool Wide) {
304   if (Wide)
305     OS << "\t.seh_save_regs_w\t";
306   else
307     OS << "\t.seh_save_regs\t";
308   ListSeparator LS;
309   int First = -1;
310   OS << "{";
311   for (int I = 0; I <= 12; I++) {
312     if (Mask & (1 << I)) {
313       if (First < 0)
314         First = I;
315     } else {
316       if (First >= 0) {
317         printRegs(OS, LS, First, I - 1);
318         First = -1;
319       }
320     }
321   }
322   if (First >= 0)
323     printRegs(OS, LS, First, 12);
324   if (Mask & (1 << 14))
325     OS << LS << "lr";
326   OS << "}\n";
327 }
328 
emitARMWinCFISaveSP(unsigned Reg)329 void ARMTargetAsmStreamer::emitARMWinCFISaveSP(unsigned Reg) {
330   OS << "\t.seh_save_sp\tr" << Reg << "\n";
331 }
332 
emitARMWinCFISaveFRegs(unsigned First,unsigned Last)333 void ARMTargetAsmStreamer::emitARMWinCFISaveFRegs(unsigned First,
334                                                   unsigned Last) {
335   if (First != Last)
336     OS << "\t.seh_save_fregs\t{d" << First << "-d" << Last << "}\n";
337   else
338     OS << "\t.seh_save_fregs\t{d" << First << "}\n";
339 }
340 
emitARMWinCFISaveLR(unsigned Offset)341 void ARMTargetAsmStreamer::emitARMWinCFISaveLR(unsigned Offset) {
342   OS << "\t.seh_save_lr\t" << Offset << "\n";
343 }
344 
emitARMWinCFIPrologEnd(bool Fragment)345 void ARMTargetAsmStreamer::emitARMWinCFIPrologEnd(bool Fragment) {
346   if (Fragment)
347     OS << "\t.seh_endprologue_fragment\n";
348   else
349     OS << "\t.seh_endprologue\n";
350 }
351 
emitARMWinCFINop(bool Wide)352 void ARMTargetAsmStreamer::emitARMWinCFINop(bool Wide) {
353   if (Wide)
354     OS << "\t.seh_nop_w\n";
355   else
356     OS << "\t.seh_nop\n";
357 }
358 
emitARMWinCFIEpilogStart(unsigned Condition)359 void ARMTargetAsmStreamer::emitARMWinCFIEpilogStart(unsigned Condition) {
360   if (Condition == ARMCC::AL)
361     OS << "\t.seh_startepilogue\n";
362   else
363     OS << "\t.seh_startepilogue_cond\t"
364        << ARMCondCodeToString(static_cast<ARMCC::CondCodes>(Condition)) << "\n";
365 }
366 
emitARMWinCFIEpilogEnd()367 void ARMTargetAsmStreamer::emitARMWinCFIEpilogEnd() {
368   OS << "\t.seh_endepilogue\n";
369 }
370 
emitARMWinCFICustom(unsigned Opcode)371 void ARMTargetAsmStreamer::emitARMWinCFICustom(unsigned Opcode) {
372   int I;
373   for (I = 3; I > 0; I--)
374     if (Opcode & (0xffu << (8 * I)))
375       break;
376   ListSeparator LS;
377   OS << "\t.seh_custom\t";
378   for (; I >= 0; I--)
379     OS << LS << ((Opcode >> (8 * I)) & 0xff);
380   OS << "\n";
381 }
382 
383 class ARMTargetELFStreamer : public ARMTargetStreamer {
384 private:
385   StringRef CurrentVendor;
386   unsigned FPU = ARM::FK_INVALID;
387   ARM::ArchKind Arch = ARM::ArchKind::INVALID;
388   ARM::ArchKind EmittedArch = ARM::ArchKind::INVALID;
389 
390   MCSection *AttributeSection = nullptr;
391 
392   void emitArchDefaultAttributes();
393   void emitFPUDefaultAttributes();
394 
395   ARMELFStreamer &getStreamer();
396 
397   void emitFnStart() override;
398   void emitFnEnd() override;
399   void emitCantUnwind() override;
400   void emitPersonality(const MCSymbol *Personality) override;
401   void emitPersonalityIndex(unsigned Index) override;
402   void emitHandlerData() override;
403   void emitSetFP(unsigned FpReg, unsigned SpReg, int64_t Offset = 0) override;
404   void emitMovSP(unsigned Reg, int64_t Offset = 0) override;
405   void emitPad(int64_t Offset) override;
406   void emitRegSave(const SmallVectorImpl<unsigned> &RegList,
407                    bool isVector) override;
408   void emitUnwindRaw(int64_t Offset,
409                      const SmallVectorImpl<uint8_t> &Opcodes) override;
410 
411   void switchVendor(StringRef Vendor) override;
412   void emitAttribute(unsigned Attribute, unsigned Value) override;
413   void emitTextAttribute(unsigned Attribute, StringRef String) override;
414   void emitIntTextAttribute(unsigned Attribute, unsigned IntValue,
415                             StringRef StringValue) override;
416   void emitArch(ARM::ArchKind Arch) override;
417   void emitObjectArch(ARM::ArchKind Arch) override;
418   void emitFPU(unsigned FPU) override;
419   void emitInst(uint32_t Inst, char Suffix = '\0') override;
420   void finishAttributeSection() override;
421   void emitLabel(MCSymbol *Symbol) override;
422 
423   void annotateTLSDescriptorSequence(const MCSymbolRefExpr *SRE) override;
424   void emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) override;
425 
426   // Reset state between object emissions
427   void reset() override;
428 
429 public:
ARMTargetELFStreamer(MCStreamer & S)430   ARMTargetELFStreamer(MCStreamer &S)
431     : ARMTargetStreamer(S), CurrentVendor("aeabi") {}
432 };
433 
434 /// Extend the generic ELFStreamer class so that it can emit mapping symbols at
435 /// the appropriate points in the object files. These symbols are defined in the
436 /// ARM ELF ABI: infocenter.arm.com/help/topic/com.arm.../IHI0044D_aaelf.pdf.
437 ///
438 /// In brief: $a, $t or $d should be emitted at the start of each contiguous
439 /// region of ARM code, Thumb code or data in a section. In practice, this
440 /// emission does not rely on explicit assembler directives but on inherent
441 /// properties of the directives doing the emission (e.g. ".byte" is data, "add
442 /// r0, r0, r0" an instruction).
443 ///
444 /// As a result this system is orthogonal to the DataRegion infrastructure used
445 /// by MachO. Beware!
446 class ARMELFStreamer : public MCELFStreamer {
447 public:
448   friend class ARMTargetELFStreamer;
449 
ARMELFStreamer(MCContext & Context,std::unique_ptr<MCAsmBackend> TAB,std::unique_ptr<MCObjectWriter> OW,std::unique_ptr<MCCodeEmitter> Emitter,bool IsThumb,bool IsAndroid)450   ARMELFStreamer(MCContext &Context, std::unique_ptr<MCAsmBackend> TAB,
451                  std::unique_ptr<MCObjectWriter> OW,
452                  std::unique_ptr<MCCodeEmitter> Emitter, bool IsThumb,
453                  bool IsAndroid)
454       : MCELFStreamer(Context, std::move(TAB), std::move(OW),
455                       std::move(Emitter)),
456         IsThumb(IsThumb), IsAndroid(IsAndroid) {
457     EHReset();
458   }
459 
460   ~ARMELFStreamer() override = default;
461 
462   void finishImpl() override;
463 
464   // ARM exception handling directives
465   void emitFnStart();
466   void emitFnEnd();
467   void emitCantUnwind();
468   void emitPersonality(const MCSymbol *Per);
469   void emitPersonalityIndex(unsigned index);
470   void emitHandlerData();
471   void emitSetFP(unsigned NewFpReg, unsigned NewSpReg, int64_t Offset = 0);
472   void emitMovSP(unsigned Reg, int64_t Offset = 0);
473   void emitPad(int64_t Offset);
474   void emitRegSave(const SmallVectorImpl<unsigned> &RegList, bool isVector);
475   void emitUnwindRaw(int64_t Offset, const SmallVectorImpl<uint8_t> &Opcodes);
emitFill(const MCExpr & NumBytes,uint64_t FillValue,SMLoc Loc)476   void emitFill(const MCExpr &NumBytes, uint64_t FillValue,
477                 SMLoc Loc) override {
478     emitDataMappingSymbol();
479     MCObjectStreamer::emitFill(NumBytes, FillValue, Loc);
480   }
481 
changeSection(MCSection * Section,const MCExpr * Subsection)482   void changeSection(MCSection *Section, const MCExpr *Subsection) override {
483     LastMappingSymbols[getCurrentSection().first] = std::move(LastEMSInfo);
484     MCELFStreamer::changeSection(Section, Subsection);
485     auto LastMappingSymbol = LastMappingSymbols.find(Section);
486     if (LastMappingSymbol != LastMappingSymbols.end()) {
487       LastEMSInfo = std::move(LastMappingSymbol->second);
488       return;
489     }
490     LastEMSInfo.reset(new ElfMappingSymbolInfo(SMLoc(), nullptr, 0));
491   }
492 
493   /// This function is the one used to emit instruction data into the ELF
494   /// streamer. We override it to add the appropriate mapping symbol if
495   /// necessary.
emitInstruction(const MCInst & Inst,const MCSubtargetInfo & STI)496   void emitInstruction(const MCInst &Inst,
497                        const MCSubtargetInfo &STI) override {
498     if (IsThumb)
499       EmitThumbMappingSymbol();
500     else
501       EmitARMMappingSymbol();
502 
503     MCELFStreamer::emitInstruction(Inst, STI);
504   }
505 
emitInst(uint32_t Inst,char Suffix)506   void emitInst(uint32_t Inst, char Suffix) {
507     unsigned Size;
508     char Buffer[4];
509     const bool LittleEndian = getContext().getAsmInfo()->isLittleEndian();
510 
511     switch (Suffix) {
512     case '\0':
513       Size = 4;
514 
515       assert(!IsThumb);
516       EmitARMMappingSymbol();
517       for (unsigned II = 0, IE = Size; II != IE; II++) {
518         const unsigned I = LittleEndian ? (Size - II - 1) : II;
519         Buffer[Size - II - 1] = uint8_t(Inst >> I * CHAR_BIT);
520       }
521 
522       break;
523     case 'n':
524     case 'w':
525       Size = (Suffix == 'n' ? 2 : 4);
526 
527       assert(IsThumb);
528       EmitThumbMappingSymbol();
529       // Thumb wide instructions are emitted as a pair of 16-bit words of the
530       // appropriate endianness.
531       for (unsigned II = 0, IE = Size; II != IE; II = II + 2) {
532         const unsigned I0 = LittleEndian ? II + 0 : II + 1;
533         const unsigned I1 = LittleEndian ? II + 1 : II + 0;
534         Buffer[Size - II - 2] = uint8_t(Inst >> I0 * CHAR_BIT);
535         Buffer[Size - II - 1] = uint8_t(Inst >> I1 * CHAR_BIT);
536       }
537 
538       break;
539     default:
540       llvm_unreachable("Invalid Suffix");
541     }
542 
543     MCELFStreamer::emitBytes(StringRef(Buffer, Size));
544   }
545 
546   /// This is one of the functions used to emit data into an ELF section, so the
547   /// ARM streamer overrides it to add the appropriate mapping symbol ($d) if
548   /// necessary.
emitBytes(StringRef Data)549   void emitBytes(StringRef Data) override {
550     emitDataMappingSymbol();
551     MCELFStreamer::emitBytes(Data);
552   }
553 
FlushPendingMappingSymbol()554   void FlushPendingMappingSymbol() {
555     if (!LastEMSInfo->hasInfo())
556       return;
557     ElfMappingSymbolInfo *EMS = LastEMSInfo.get();
558     EmitMappingSymbol("$d", EMS->Loc, EMS->F, EMS->Offset);
559     EMS->resetInfo();
560   }
561 
562   /// This is one of the functions used to emit data into an ELF section, so the
563   /// ARM streamer overrides it to add the appropriate mapping symbol ($d) if
564   /// necessary.
emitValueImpl(const MCExpr * Value,unsigned Size,SMLoc Loc)565   void emitValueImpl(const MCExpr *Value, unsigned Size, SMLoc Loc) override {
566     if (const MCSymbolRefExpr *SRE = dyn_cast_or_null<MCSymbolRefExpr>(Value)) {
567       if (SRE->getKind() == MCSymbolRefExpr::VK_ARM_SBREL && !(Size == 4)) {
568         getContext().reportError(Loc, "relocated expression must be 32-bit");
569         return;
570       }
571       getOrCreateDataFragment();
572     }
573 
574     emitDataMappingSymbol();
575     MCELFStreamer::emitValueImpl(Value, Size, Loc);
576   }
577 
emitAssemblerFlag(MCAssemblerFlag Flag)578   void emitAssemblerFlag(MCAssemblerFlag Flag) override {
579     MCELFStreamer::emitAssemblerFlag(Flag);
580 
581     switch (Flag) {
582     case MCAF_SyntaxUnified:
583       return; // no-op here.
584     case MCAF_Code16:
585       IsThumb = true;
586       return; // Change to Thumb mode
587     case MCAF_Code32:
588       IsThumb = false;
589       return; // Change to ARM mode
590     case MCAF_Code64:
591       return;
592     case MCAF_SubsectionsViaSymbols:
593       return;
594     }
595   }
596 
597   /// If a label is defined before the .type directive sets the label's type
598   /// then the label can't be recorded as thumb function when the label is
599   /// defined. We override emitSymbolAttribute() which is called as part of the
600   /// parsing of .type so that if the symbol has already been defined we can
601   /// record the label as Thumb. FIXME: there is a corner case where the state
602   /// is changed in between the label definition and the .type directive, this
603   /// is not expected to occur in practice and handling it would require the
604   /// backend to track IsThumb for every label.
emitSymbolAttribute(MCSymbol * Symbol,MCSymbolAttr Attribute)605   bool emitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute) override {
606     bool Val = MCELFStreamer::emitSymbolAttribute(Symbol, Attribute);
607 
608     if (!IsThumb)
609       return Val;
610 
611     unsigned Type = cast<MCSymbolELF>(Symbol)->getType();
612     if ((Type == ELF::STT_FUNC || Type == ELF::STT_GNU_IFUNC) &&
613         Symbol->isDefined())
614       getAssembler().setIsThumbFunc(Symbol);
615 
616     return Val;
617   };
618 
619 private:
620   enum ElfMappingSymbol {
621     EMS_None,
622     EMS_ARM,
623     EMS_Thumb,
624     EMS_Data
625   };
626 
627   struct ElfMappingSymbolInfo {
ElfMappingSymbolInfo__anon063f8e610111::ARMELFStreamer::ElfMappingSymbolInfo628     explicit ElfMappingSymbolInfo(SMLoc Loc, MCFragment *F, uint64_t O)
629         : Loc(Loc), F(F), Offset(O), State(EMS_None) {}
resetInfo__anon063f8e610111::ARMELFStreamer::ElfMappingSymbolInfo630     void resetInfo() {
631       F = nullptr;
632       Offset = 0;
633     }
hasInfo__anon063f8e610111::ARMELFStreamer::ElfMappingSymbolInfo634     bool hasInfo() { return F != nullptr; }
635     SMLoc Loc;
636     MCFragment *F;
637     uint64_t Offset;
638     ElfMappingSymbol State;
639   };
640 
emitDataMappingSymbol()641   void emitDataMappingSymbol() {
642     if (LastEMSInfo->State == EMS_Data)
643       return;
644     else if (LastEMSInfo->State == EMS_None) {
645       // This is a tentative symbol, it won't really be emitted until it's
646       // actually needed.
647       ElfMappingSymbolInfo *EMS = LastEMSInfo.get();
648       auto *DF = dyn_cast_or_null<MCDataFragment>(getCurrentFragment());
649       if (!DF)
650         return;
651       EMS->Loc = SMLoc();
652       EMS->F = getCurrentFragment();
653       EMS->Offset = DF->getContents().size();
654       LastEMSInfo->State = EMS_Data;
655       return;
656     }
657     EmitMappingSymbol("$d");
658     LastEMSInfo->State = EMS_Data;
659   }
660 
EmitThumbMappingSymbol()661   void EmitThumbMappingSymbol() {
662     if (LastEMSInfo->State == EMS_Thumb)
663       return;
664     FlushPendingMappingSymbol();
665     EmitMappingSymbol("$t");
666     LastEMSInfo->State = EMS_Thumb;
667   }
668 
EmitARMMappingSymbol()669   void EmitARMMappingSymbol() {
670     if (LastEMSInfo->State == EMS_ARM)
671       return;
672     FlushPendingMappingSymbol();
673     EmitMappingSymbol("$a");
674     LastEMSInfo->State = EMS_ARM;
675   }
676 
EmitMappingSymbol(StringRef Name)677   void EmitMappingSymbol(StringRef Name) {
678     auto *Symbol = cast<MCSymbolELF>(getContext().getOrCreateSymbol(
679         Name + "." + Twine(MappingSymbolCounter++)));
680     emitLabel(Symbol);
681 
682     Symbol->setType(ELF::STT_NOTYPE);
683     Symbol->setBinding(ELF::STB_LOCAL);
684   }
685 
EmitMappingSymbol(StringRef Name,SMLoc Loc,MCFragment * F,uint64_t Offset)686   void EmitMappingSymbol(StringRef Name, SMLoc Loc, MCFragment *F,
687                          uint64_t Offset) {
688     auto *Symbol = cast<MCSymbolELF>(getContext().getOrCreateSymbol(
689         Name + "." + Twine(MappingSymbolCounter++)));
690     emitLabelAtPos(Symbol, Loc, F, Offset);
691     Symbol->setType(ELF::STT_NOTYPE);
692     Symbol->setBinding(ELF::STB_LOCAL);
693   }
694 
emitThumbFunc(MCSymbol * Func)695   void emitThumbFunc(MCSymbol *Func) override {
696     getAssembler().setIsThumbFunc(Func);
697     emitSymbolAttribute(Func, MCSA_ELF_TypeFunction);
698   }
699 
700   // Helper functions for ARM exception handling directives
701   void EHReset();
702 
703   // Reset state between object emissions
704   void reset() override;
705 
706   void EmitPersonalityFixup(StringRef Name);
707   void FlushPendingOffset();
708   void FlushUnwindOpcodes(bool NoHandlerData);
709 
710   void SwitchToEHSection(StringRef Prefix, unsigned Type, unsigned Flags,
711                          SectionKind Kind, const MCSymbol &Fn);
712   void SwitchToExTabSection(const MCSymbol &FnStart);
713   void SwitchToExIdxSection(const MCSymbol &FnStart);
714 
715   void EmitFixup(const MCExpr *Expr, MCFixupKind Kind);
716 
717   bool IsThumb;
718   bool IsAndroid;
719   int64_t MappingSymbolCounter = 0;
720 
721   DenseMap<const MCSection *, std::unique_ptr<ElfMappingSymbolInfo>>
722       LastMappingSymbols;
723 
724   std::unique_ptr<ElfMappingSymbolInfo> LastEMSInfo;
725 
726   // ARM Exception Handling Frame Information
727   MCSymbol *ExTab;
728   MCSymbol *FnStart;
729   const MCSymbol *Personality;
730   unsigned PersonalityIndex;
731   unsigned FPReg; // Frame pointer register
732   int64_t FPOffset; // Offset: (final frame pointer) - (initial $sp)
733   int64_t SPOffset; // Offset: (final $sp) - (initial $sp)
734   int64_t PendingOffset; // Offset: (final $sp) - (emitted $sp)
735   bool UsedFP;
736   bool CantUnwind;
737   SmallVector<uint8_t, 64> Opcodes;
738   UnwindOpcodeAssembler UnwindOpAsm;
739 };
740 
741 } // end anonymous namespace
742 
getStreamer()743 ARMELFStreamer &ARMTargetELFStreamer::getStreamer() {
744   return static_cast<ARMELFStreamer &>(Streamer);
745 }
746 
emitFnStart()747 void ARMTargetELFStreamer::emitFnStart() { getStreamer().emitFnStart(); }
emitFnEnd()748 void ARMTargetELFStreamer::emitFnEnd() { getStreamer().emitFnEnd(); }
emitCantUnwind()749 void ARMTargetELFStreamer::emitCantUnwind() { getStreamer().emitCantUnwind(); }
750 
emitPersonality(const MCSymbol * Personality)751 void ARMTargetELFStreamer::emitPersonality(const MCSymbol *Personality) {
752   getStreamer().emitPersonality(Personality);
753 }
754 
emitPersonalityIndex(unsigned Index)755 void ARMTargetELFStreamer::emitPersonalityIndex(unsigned Index) {
756   getStreamer().emitPersonalityIndex(Index);
757 }
758 
emitHandlerData()759 void ARMTargetELFStreamer::emitHandlerData() {
760   getStreamer().emitHandlerData();
761 }
762 
emitSetFP(unsigned FpReg,unsigned SpReg,int64_t Offset)763 void ARMTargetELFStreamer::emitSetFP(unsigned FpReg, unsigned SpReg,
764                                      int64_t Offset) {
765   getStreamer().emitSetFP(FpReg, SpReg, Offset);
766 }
767 
emitMovSP(unsigned Reg,int64_t Offset)768 void ARMTargetELFStreamer::emitMovSP(unsigned Reg, int64_t Offset) {
769   getStreamer().emitMovSP(Reg, Offset);
770 }
771 
emitPad(int64_t Offset)772 void ARMTargetELFStreamer::emitPad(int64_t Offset) {
773   getStreamer().emitPad(Offset);
774 }
775 
emitRegSave(const SmallVectorImpl<unsigned> & RegList,bool isVector)776 void ARMTargetELFStreamer::emitRegSave(const SmallVectorImpl<unsigned> &RegList,
777                                        bool isVector) {
778   getStreamer().emitRegSave(RegList, isVector);
779 }
780 
emitUnwindRaw(int64_t Offset,const SmallVectorImpl<uint8_t> & Opcodes)781 void ARMTargetELFStreamer::emitUnwindRaw(int64_t Offset,
782                                       const SmallVectorImpl<uint8_t> &Opcodes) {
783   getStreamer().emitUnwindRaw(Offset, Opcodes);
784 }
785 
switchVendor(StringRef Vendor)786 void ARMTargetELFStreamer::switchVendor(StringRef Vendor) {
787   assert(!Vendor.empty() && "Vendor cannot be empty.");
788 
789   if (CurrentVendor == Vendor)
790     return;
791 
792   if (!CurrentVendor.empty())
793     finishAttributeSection();
794 
795   assert(getStreamer().Contents.empty() &&
796          ".ARM.attributes should be flushed before changing vendor");
797   CurrentVendor = Vendor;
798 
799 }
800 
emitAttribute(unsigned Attribute,unsigned Value)801 void ARMTargetELFStreamer::emitAttribute(unsigned Attribute, unsigned Value) {
802   getStreamer().setAttributeItem(Attribute, Value,
803                                  /* OverwriteExisting= */ true);
804 }
805 
emitTextAttribute(unsigned Attribute,StringRef Value)806 void ARMTargetELFStreamer::emitTextAttribute(unsigned Attribute,
807                                              StringRef Value) {
808   getStreamer().setAttributeItem(Attribute, Value,
809                                  /* OverwriteExisting= */ true);
810 }
811 
emitIntTextAttribute(unsigned Attribute,unsigned IntValue,StringRef StringValue)812 void ARMTargetELFStreamer::emitIntTextAttribute(unsigned Attribute,
813                                                 unsigned IntValue,
814                                                 StringRef StringValue) {
815   getStreamer().setAttributeItems(Attribute, IntValue, StringValue,
816                                   /* OverwriteExisting= */ true);
817 }
818 
emitArch(ARM::ArchKind Value)819 void ARMTargetELFStreamer::emitArch(ARM::ArchKind Value) {
820   Arch = Value;
821 }
822 
emitObjectArch(ARM::ArchKind Value)823 void ARMTargetELFStreamer::emitObjectArch(ARM::ArchKind Value) {
824   EmittedArch = Value;
825 }
826 
emitArchDefaultAttributes()827 void ARMTargetELFStreamer::emitArchDefaultAttributes() {
828   using namespace ARMBuildAttrs;
829   ARMELFStreamer &S = getStreamer();
830 
831   S.setAttributeItem(CPU_name, ARM::getCPUAttr(Arch), false);
832 
833   if (EmittedArch == ARM::ArchKind::INVALID)
834     S.setAttributeItem(CPU_arch, ARM::getArchAttr(Arch), false);
835   else
836     S.setAttributeItem(CPU_arch, ARM::getArchAttr(EmittedArch), false);
837 
838   switch (Arch) {
839   case ARM::ArchKind::ARMV4:
840     S.setAttributeItem(ARM_ISA_use, Allowed, false);
841     break;
842 
843   case ARM::ArchKind::ARMV4T:
844   case ARM::ArchKind::ARMV5T:
845   case ARM::ArchKind::XSCALE:
846   case ARM::ArchKind::ARMV5TE:
847   case ARM::ArchKind::ARMV6:
848     S.setAttributeItem(ARM_ISA_use, Allowed, false);
849     S.setAttributeItem(THUMB_ISA_use, Allowed, false);
850     break;
851 
852   case ARM::ArchKind::ARMV6T2:
853     S.setAttributeItem(ARM_ISA_use, Allowed, false);
854     S.setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
855     break;
856 
857   case ARM::ArchKind::ARMV6K:
858   case ARM::ArchKind::ARMV6KZ:
859     S.setAttributeItem(ARM_ISA_use, Allowed, false);
860     S.setAttributeItem(THUMB_ISA_use, Allowed, false);
861     S.setAttributeItem(Virtualization_use, AllowTZ, false);
862     break;
863 
864   case ARM::ArchKind::ARMV6M:
865     S.setAttributeItem(THUMB_ISA_use, Allowed, false);
866     break;
867 
868   case ARM::ArchKind::ARMV7A:
869     S.setAttributeItem(CPU_arch_profile, ApplicationProfile, false);
870     S.setAttributeItem(ARM_ISA_use, Allowed, false);
871     S.setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
872     break;
873 
874   case ARM::ArchKind::ARMV7R:
875     S.setAttributeItem(CPU_arch_profile, RealTimeProfile, false);
876     S.setAttributeItem(ARM_ISA_use, Allowed, false);
877     S.setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
878     break;
879 
880   case ARM::ArchKind::ARMV7EM:
881   case ARM::ArchKind::ARMV7M:
882     S.setAttributeItem(CPU_arch_profile, MicroControllerProfile, false);
883     S.setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
884     break;
885 
886   case ARM::ArchKind::ARMV8A:
887   case ARM::ArchKind::ARMV8_1A:
888   case ARM::ArchKind::ARMV8_2A:
889   case ARM::ArchKind::ARMV8_3A:
890   case ARM::ArchKind::ARMV8_4A:
891   case ARM::ArchKind::ARMV8_5A:
892   case ARM::ArchKind::ARMV8_6A:
893   case ARM::ArchKind::ARMV8_7A:
894   case ARM::ArchKind::ARMV8_8A:
895   case ARM::ArchKind::ARMV8_9A:
896   case ARM::ArchKind::ARMV9A:
897   case ARM::ArchKind::ARMV9_1A:
898   case ARM::ArchKind::ARMV9_2A:
899   case ARM::ArchKind::ARMV9_3A:
900   case ARM::ArchKind::ARMV9_4A:
901     S.setAttributeItem(CPU_arch_profile, ApplicationProfile, false);
902     S.setAttributeItem(ARM_ISA_use, Allowed, false);
903     S.setAttributeItem(THUMB_ISA_use, AllowThumb32, false);
904     S.setAttributeItem(MPextension_use, Allowed, false);
905     S.setAttributeItem(Virtualization_use, AllowTZVirtualization, false);
906     break;
907 
908   case ARM::ArchKind::ARMV8MBaseline:
909   case ARM::ArchKind::ARMV8MMainline:
910     S.setAttributeItem(THUMB_ISA_use, AllowThumbDerived, false);
911     S.setAttributeItem(CPU_arch_profile, MicroControllerProfile, false);
912     break;
913 
914   case ARM::ArchKind::IWMMXT:
915     S.setAttributeItem(ARM_ISA_use, Allowed, false);
916     S.setAttributeItem(THUMB_ISA_use, Allowed, false);
917     S.setAttributeItem(WMMX_arch, AllowWMMXv1, false);
918     break;
919 
920   case ARM::ArchKind::IWMMXT2:
921     S.setAttributeItem(ARM_ISA_use, Allowed, false);
922     S.setAttributeItem(THUMB_ISA_use, Allowed, false);
923     S.setAttributeItem(WMMX_arch, AllowWMMXv2, false);
924     break;
925 
926   default:
927     report_fatal_error("Unknown Arch: " + Twine(ARM::getArchName(Arch)));
928     break;
929   }
930 }
931 
emitFPU(unsigned Value)932 void ARMTargetELFStreamer::emitFPU(unsigned Value) {
933   FPU = Value;
934 }
935 
emitFPUDefaultAttributes()936 void ARMTargetELFStreamer::emitFPUDefaultAttributes() {
937   ARMELFStreamer &S = getStreamer();
938 
939   switch (FPU) {
940   case ARM::FK_VFP:
941   case ARM::FK_VFPV2:
942     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPv2,
943                        /* OverwriteExisting= */ false);
944     break;
945 
946   case ARM::FK_VFPV3:
947     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPv3A,
948                        /* OverwriteExisting= */ false);
949     break;
950 
951   case ARM::FK_VFPV3_FP16:
952     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPv3A,
953                        /* OverwriteExisting= */ false);
954     S.setAttributeItem(ARMBuildAttrs::FP_HP_extension, ARMBuildAttrs::AllowHPFP,
955                        /* OverwriteExisting= */ false);
956     break;
957 
958   case ARM::FK_VFPV3_D16:
959     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPv3B,
960                        /* OverwriteExisting= */ false);
961     break;
962 
963   case ARM::FK_VFPV3_D16_FP16:
964     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPv3B,
965                        /* OverwriteExisting= */ false);
966     S.setAttributeItem(ARMBuildAttrs::FP_HP_extension, ARMBuildAttrs::AllowHPFP,
967                        /* OverwriteExisting= */ false);
968     break;
969 
970   case ARM::FK_VFPV3XD:
971     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPv3B,
972                        /* OverwriteExisting= */ false);
973     break;
974   case ARM::FK_VFPV3XD_FP16:
975     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPv3B,
976                        /* OverwriteExisting= */ false);
977     S.setAttributeItem(ARMBuildAttrs::FP_HP_extension, ARMBuildAttrs::AllowHPFP,
978                        /* OverwriteExisting= */ false);
979     break;
980 
981   case ARM::FK_VFPV4:
982     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPv4A,
983                        /* OverwriteExisting= */ false);
984     break;
985 
986   // ABI_HardFP_use is handled in ARMAsmPrinter, so _SP_D16 is treated the same
987   // as _D16 here.
988   case ARM::FK_FPV4_SP_D16:
989   case ARM::FK_VFPV4_D16:
990     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPv4B,
991                        /* OverwriteExisting= */ false);
992     break;
993 
994   case ARM::FK_FP_ARMV8:
995     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPARMv8A,
996                        /* OverwriteExisting= */ false);
997     break;
998 
999   // FPV5_D16 is identical to FP_ARMV8 except for the number of D registers, so
1000   // uses the FP_ARMV8_D16 build attribute.
1001   case ARM::FK_FPV5_SP_D16:
1002   case ARM::FK_FPV5_D16:
1003     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPARMv8B,
1004                        /* OverwriteExisting= */ false);
1005     break;
1006 
1007   case ARM::FK_NEON:
1008     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPv3A,
1009                        /* OverwriteExisting= */ false);
1010     S.setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
1011                        ARMBuildAttrs::AllowNeon,
1012                        /* OverwriteExisting= */ false);
1013     break;
1014 
1015   case ARM::FK_NEON_FP16:
1016     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPv3A,
1017                        /* OverwriteExisting= */ false);
1018     S.setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
1019                        ARMBuildAttrs::AllowNeon,
1020                        /* OverwriteExisting= */ false);
1021     S.setAttributeItem(ARMBuildAttrs::FP_HP_extension, ARMBuildAttrs::AllowHPFP,
1022                        /* OverwriteExisting= */ false);
1023     break;
1024 
1025   case ARM::FK_NEON_VFPV4:
1026     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPv4A,
1027                        /* OverwriteExisting= */ false);
1028     S.setAttributeItem(ARMBuildAttrs::Advanced_SIMD_arch,
1029                        ARMBuildAttrs::AllowNeon2,
1030                        /* OverwriteExisting= */ false);
1031     break;
1032 
1033   case ARM::FK_NEON_FP_ARMV8:
1034   case ARM::FK_CRYPTO_NEON_FP_ARMV8:
1035     S.setAttributeItem(ARMBuildAttrs::FP_arch, ARMBuildAttrs::AllowFPARMv8A,
1036                        /* OverwriteExisting= */ false);
1037     // 'Advanced_SIMD_arch' must be emitted not here, but within
1038     // ARMAsmPrinter::emitAttributes(), depending on hasV8Ops() and hasV8_1a()
1039     break;
1040 
1041   case ARM::FK_SOFTVFP:
1042   case ARM::FK_NONE:
1043     break;
1044 
1045   default:
1046     report_fatal_error("Unknown FPU: " + Twine(FPU));
1047     break;
1048   }
1049 }
1050 
finishAttributeSection()1051 void ARMTargetELFStreamer::finishAttributeSection() {
1052   ARMELFStreamer &S = getStreamer();
1053 
1054   if (FPU != ARM::FK_INVALID)
1055     emitFPUDefaultAttributes();
1056 
1057   if (Arch != ARM::ArchKind::INVALID)
1058     emitArchDefaultAttributes();
1059 
1060   if (S.Contents.empty())
1061     return;
1062 
1063   auto LessTag = [](const MCELFStreamer::AttributeItem &LHS,
1064                     const MCELFStreamer::AttributeItem &RHS) -> bool {
1065     // The conformance tag must be emitted first when serialised into an
1066     // object file. Specifically, the addenda to the ARM ABI states that
1067     // (2.3.7.4):
1068     //
1069     // "To simplify recognition by consumers in the common case of claiming
1070     // conformity for the whole file, this tag should be emitted first in a
1071     // file-scope sub-subsection of the first public subsection of the
1072     // attributes section."
1073     //
1074     // So it is special-cased in this comparison predicate when the
1075     // attributes are sorted in finishAttributeSection().
1076     return (RHS.Tag != ARMBuildAttrs::conformance) &&
1077            ((LHS.Tag == ARMBuildAttrs::conformance) || (LHS.Tag < RHS.Tag));
1078   };
1079   llvm::sort(S.Contents, LessTag);
1080 
1081   S.emitAttributesSection(CurrentVendor, ".ARM.attributes",
1082                           ELF::SHT_ARM_ATTRIBUTES, AttributeSection);
1083 
1084   FPU = ARM::FK_INVALID;
1085 }
1086 
emitLabel(MCSymbol * Symbol)1087 void ARMTargetELFStreamer::emitLabel(MCSymbol *Symbol) {
1088   ARMELFStreamer &Streamer = getStreamer();
1089   if (!Streamer.IsThumb)
1090     return;
1091 
1092   Streamer.getAssembler().registerSymbol(*Symbol);
1093   unsigned Type = cast<MCSymbolELF>(Symbol)->getType();
1094   if (Type == ELF::STT_FUNC || Type == ELF::STT_GNU_IFUNC)
1095     Streamer.emitThumbFunc(Symbol);
1096 }
1097 
annotateTLSDescriptorSequence(const MCSymbolRefExpr * S)1098 void ARMTargetELFStreamer::annotateTLSDescriptorSequence(
1099     const MCSymbolRefExpr *S) {
1100   getStreamer().EmitFixup(S, FK_Data_4);
1101 }
1102 
emitThumbSet(MCSymbol * Symbol,const MCExpr * Value)1103 void ARMTargetELFStreamer::emitThumbSet(MCSymbol *Symbol, const MCExpr *Value) {
1104   if (const MCSymbolRefExpr *SRE = dyn_cast<MCSymbolRefExpr>(Value)) {
1105     const MCSymbol &Sym = SRE->getSymbol();
1106     if (!Sym.isDefined()) {
1107       getStreamer().emitAssignment(Symbol, Value);
1108       return;
1109     }
1110   }
1111 
1112   getStreamer().emitThumbFunc(Symbol);
1113   getStreamer().emitAssignment(Symbol, Value);
1114 }
1115 
emitInst(uint32_t Inst,char Suffix)1116 void ARMTargetELFStreamer::emitInst(uint32_t Inst, char Suffix) {
1117   getStreamer().emitInst(Inst, Suffix);
1118 }
1119 
reset()1120 void ARMTargetELFStreamer::reset() { AttributeSection = nullptr; }
1121 
finishImpl()1122 void ARMELFStreamer::finishImpl() {
1123   MCTargetStreamer &TS = *getTargetStreamer();
1124   ARMTargetStreamer &ATS = static_cast<ARMTargetStreamer &>(TS);
1125   ATS.finishAttributeSection();
1126 
1127   MCELFStreamer::finishImpl();
1128 }
1129 
reset()1130 void ARMELFStreamer::reset() {
1131   MCTargetStreamer &TS = *getTargetStreamer();
1132   ARMTargetStreamer &ATS = static_cast<ARMTargetStreamer &>(TS);
1133   ATS.reset();
1134   MappingSymbolCounter = 0;
1135   MCELFStreamer::reset();
1136   LastMappingSymbols.clear();
1137   LastEMSInfo.reset();
1138   // MCELFStreamer clear's the assembler's e_flags. However, for
1139   // arm we manually set the ABI version on streamer creation, so
1140   // do the same here
1141   getAssembler().setELFHeaderEFlags(ELF::EF_ARM_EABI_VER5);
1142 }
1143 
SwitchToEHSection(StringRef Prefix,unsigned Type,unsigned Flags,SectionKind Kind,const MCSymbol & Fn)1144 inline void ARMELFStreamer::SwitchToEHSection(StringRef Prefix,
1145                                               unsigned Type,
1146                                               unsigned Flags,
1147                                               SectionKind Kind,
1148                                               const MCSymbol &Fn) {
1149   const MCSectionELF &FnSection =
1150     static_cast<const MCSectionELF &>(Fn.getSection());
1151 
1152   // Create the name for new section
1153   StringRef FnSecName(FnSection.getName());
1154   SmallString<128> EHSecName(Prefix);
1155   if (FnSecName != ".text") {
1156     EHSecName += FnSecName;
1157   }
1158 
1159   // Get .ARM.extab or .ARM.exidx section
1160   const MCSymbolELF *Group = FnSection.getGroup();
1161   if (Group)
1162     Flags |= ELF::SHF_GROUP;
1163   MCSectionELF *EHSection = getContext().getELFSection(
1164       EHSecName, Type, Flags, 0, Group, /*IsComdat=*/true,
1165       FnSection.getUniqueID(),
1166       static_cast<const MCSymbolELF *>(FnSection.getBeginSymbol()));
1167 
1168   assert(EHSection && "Failed to get the required EH section");
1169 
1170   // Switch to .ARM.extab or .ARM.exidx section
1171   switchSection(EHSection);
1172   emitValueToAlignment(Align(4), 0, 1, 0);
1173 }
1174 
SwitchToExTabSection(const MCSymbol & FnStart)1175 inline void ARMELFStreamer::SwitchToExTabSection(const MCSymbol &FnStart) {
1176   SwitchToEHSection(".ARM.extab", ELF::SHT_PROGBITS, ELF::SHF_ALLOC,
1177                     SectionKind::getData(), FnStart);
1178 }
1179 
SwitchToExIdxSection(const MCSymbol & FnStart)1180 inline void ARMELFStreamer::SwitchToExIdxSection(const MCSymbol &FnStart) {
1181   SwitchToEHSection(".ARM.exidx", ELF::SHT_ARM_EXIDX,
1182                     ELF::SHF_ALLOC | ELF::SHF_LINK_ORDER,
1183                     SectionKind::getData(), FnStart);
1184 }
1185 
EmitFixup(const MCExpr * Expr,MCFixupKind Kind)1186 void ARMELFStreamer::EmitFixup(const MCExpr *Expr, MCFixupKind Kind) {
1187   MCDataFragment *Frag = getOrCreateDataFragment();
1188   Frag->getFixups().push_back(MCFixup::create(Frag->getContents().size(), Expr,
1189                                               Kind));
1190 }
1191 
EHReset()1192 void ARMELFStreamer::EHReset() {
1193   ExTab = nullptr;
1194   FnStart = nullptr;
1195   Personality = nullptr;
1196   PersonalityIndex = ARM::EHABI::NUM_PERSONALITY_INDEX;
1197   FPReg = ARM::SP;
1198   FPOffset = 0;
1199   SPOffset = 0;
1200   PendingOffset = 0;
1201   UsedFP = false;
1202   CantUnwind = false;
1203 
1204   Opcodes.clear();
1205   UnwindOpAsm.Reset();
1206 }
1207 
emitFnStart()1208 void ARMELFStreamer::emitFnStart() {
1209   assert(FnStart == nullptr);
1210   FnStart = getContext().createTempSymbol();
1211   emitLabel(FnStart);
1212 }
1213 
emitFnEnd()1214 void ARMELFStreamer::emitFnEnd() {
1215   assert(FnStart && ".fnstart must precedes .fnend");
1216 
1217   // Emit unwind opcodes if there is no .handlerdata directive
1218   if (!ExTab && !CantUnwind)
1219     FlushUnwindOpcodes(true);
1220 
1221   // Emit the exception index table entry
1222   SwitchToExIdxSection(*FnStart);
1223 
1224   // The EHABI requires a dependency preserving R_ARM_NONE relocation to the
1225   // personality routine to protect it from an arbitrary platform's static
1226   // linker garbage collection. We disable this for Android where the unwinder
1227   // is either dynamically linked or directly references the personality
1228   // routine.
1229   if (PersonalityIndex < ARM::EHABI::NUM_PERSONALITY_INDEX && !IsAndroid)
1230     EmitPersonalityFixup(GetAEABIUnwindPersonalityName(PersonalityIndex));
1231 
1232   const MCSymbolRefExpr *FnStartRef =
1233     MCSymbolRefExpr::create(FnStart,
1234                             MCSymbolRefExpr::VK_ARM_PREL31,
1235                             getContext());
1236 
1237   emitValue(FnStartRef, 4);
1238 
1239   if (CantUnwind) {
1240     emitInt32(ARM::EHABI::EXIDX_CANTUNWIND);
1241   } else if (ExTab) {
1242     // Emit a reference to the unwind opcodes in the ".ARM.extab" section.
1243     const MCSymbolRefExpr *ExTabEntryRef =
1244       MCSymbolRefExpr::create(ExTab,
1245                               MCSymbolRefExpr::VK_ARM_PREL31,
1246                               getContext());
1247     emitValue(ExTabEntryRef, 4);
1248   } else {
1249     // For the __aeabi_unwind_cpp_pr0, we have to emit the unwind opcodes in
1250     // the second word of exception index table entry.  The size of the unwind
1251     // opcodes should always be 4 bytes.
1252     assert(PersonalityIndex == ARM::EHABI::AEABI_UNWIND_CPP_PR0 &&
1253            "Compact model must use __aeabi_unwind_cpp_pr0 as personality");
1254     assert(Opcodes.size() == 4u &&
1255            "Unwind opcode size for __aeabi_unwind_cpp_pr0 must be equal to 4");
1256     uint64_t Intval = Opcodes[0] |
1257                       Opcodes[1] << 8 |
1258                       Opcodes[2] << 16 |
1259                       Opcodes[3] << 24;
1260     emitIntValue(Intval, Opcodes.size());
1261   }
1262 
1263   // Switch to the section containing FnStart
1264   switchSection(&FnStart->getSection());
1265 
1266   // Clean exception handling frame information
1267   EHReset();
1268 }
1269 
emitCantUnwind()1270 void ARMELFStreamer::emitCantUnwind() { CantUnwind = true; }
1271 
1272 // Add the R_ARM_NONE fixup at the same position
EmitPersonalityFixup(StringRef Name)1273 void ARMELFStreamer::EmitPersonalityFixup(StringRef Name) {
1274   const MCSymbol *PersonalitySym = getContext().getOrCreateSymbol(Name);
1275 
1276   const MCSymbolRefExpr *PersonalityRef = MCSymbolRefExpr::create(
1277       PersonalitySym, MCSymbolRefExpr::VK_ARM_NONE, getContext());
1278 
1279   visitUsedExpr(*PersonalityRef);
1280   MCDataFragment *DF = getOrCreateDataFragment();
1281   DF->getFixups().push_back(MCFixup::create(DF->getContents().size(),
1282                                             PersonalityRef,
1283                                             MCFixup::getKindForSize(4, false)));
1284 }
1285 
FlushPendingOffset()1286 void ARMELFStreamer::FlushPendingOffset() {
1287   if (PendingOffset != 0) {
1288     UnwindOpAsm.EmitSPOffset(-PendingOffset);
1289     PendingOffset = 0;
1290   }
1291 }
1292 
FlushUnwindOpcodes(bool NoHandlerData)1293 void ARMELFStreamer::FlushUnwindOpcodes(bool NoHandlerData) {
1294   // Emit the unwind opcode to restore $sp.
1295   if (UsedFP) {
1296     const MCRegisterInfo *MRI = getContext().getRegisterInfo();
1297     int64_t LastRegSaveSPOffset = SPOffset - PendingOffset;
1298     UnwindOpAsm.EmitSPOffset(LastRegSaveSPOffset - FPOffset);
1299     UnwindOpAsm.EmitSetSP(MRI->getEncodingValue(FPReg));
1300   } else {
1301     FlushPendingOffset();
1302   }
1303 
1304   // Finalize the unwind opcode sequence
1305   UnwindOpAsm.Finalize(PersonalityIndex, Opcodes);
1306 
1307   // For compact model 0, we have to emit the unwind opcodes in the .ARM.exidx
1308   // section.  Thus, we don't have to create an entry in the .ARM.extab
1309   // section.
1310   if (NoHandlerData && PersonalityIndex == ARM::EHABI::AEABI_UNWIND_CPP_PR0)
1311     return;
1312 
1313   // Switch to .ARM.extab section.
1314   SwitchToExTabSection(*FnStart);
1315 
1316   // Create .ARM.extab label for offset in .ARM.exidx
1317   assert(!ExTab);
1318   ExTab = getContext().createTempSymbol();
1319   emitLabel(ExTab);
1320 
1321   // Emit personality
1322   if (Personality) {
1323     const MCSymbolRefExpr *PersonalityRef =
1324       MCSymbolRefExpr::create(Personality,
1325                               MCSymbolRefExpr::VK_ARM_PREL31,
1326                               getContext());
1327 
1328     emitValue(PersonalityRef, 4);
1329   }
1330 
1331   // Emit unwind opcodes
1332   assert((Opcodes.size() % 4) == 0 &&
1333          "Unwind opcode size for __aeabi_cpp_unwind_pr0 must be multiple of 4");
1334   for (unsigned I = 0; I != Opcodes.size(); I += 4) {
1335     uint64_t Intval = Opcodes[I] |
1336                       Opcodes[I + 1] << 8 |
1337                       Opcodes[I + 2] << 16 |
1338                       Opcodes[I + 3] << 24;
1339     emitInt32(Intval);
1340   }
1341 
1342   // According to ARM EHABI section 9.2, if the __aeabi_unwind_cpp_pr1() or
1343   // __aeabi_unwind_cpp_pr2() is used, then the handler data must be emitted
1344   // after the unwind opcodes.  The handler data consists of several 32-bit
1345   // words, and should be terminated by zero.
1346   //
1347   // In case that the .handlerdata directive is not specified by the
1348   // programmer, we should emit zero to terminate the handler data.
1349   if (NoHandlerData && !Personality)
1350     emitInt32(0);
1351 }
1352 
emitHandlerData()1353 void ARMELFStreamer::emitHandlerData() { FlushUnwindOpcodes(false); }
1354 
emitPersonality(const MCSymbol * Per)1355 void ARMELFStreamer::emitPersonality(const MCSymbol *Per) {
1356   Personality = Per;
1357   UnwindOpAsm.setPersonality(Per);
1358 }
1359 
emitPersonalityIndex(unsigned Index)1360 void ARMELFStreamer::emitPersonalityIndex(unsigned Index) {
1361   assert(Index < ARM::EHABI::NUM_PERSONALITY_INDEX && "invalid index");
1362   PersonalityIndex = Index;
1363 }
1364 
emitSetFP(unsigned NewFPReg,unsigned NewSPReg,int64_t Offset)1365 void ARMELFStreamer::emitSetFP(unsigned NewFPReg, unsigned NewSPReg,
1366                                int64_t Offset) {
1367   assert((NewSPReg == ARM::SP || NewSPReg == FPReg) &&
1368          "the operand of .setfp directive should be either $sp or $fp");
1369 
1370   UsedFP = true;
1371   FPReg = NewFPReg;
1372 
1373   if (NewSPReg == ARM::SP)
1374     FPOffset = SPOffset + Offset;
1375   else
1376     FPOffset += Offset;
1377 }
1378 
emitMovSP(unsigned Reg,int64_t Offset)1379 void ARMELFStreamer::emitMovSP(unsigned Reg, int64_t Offset) {
1380   assert((Reg != ARM::SP && Reg != ARM::PC) &&
1381          "the operand of .movsp cannot be either sp or pc");
1382   assert(FPReg == ARM::SP && "current FP must be SP");
1383 
1384   FlushPendingOffset();
1385 
1386   FPReg = Reg;
1387   FPOffset = SPOffset + Offset;
1388 
1389   const MCRegisterInfo *MRI = getContext().getRegisterInfo();
1390   UnwindOpAsm.EmitSetSP(MRI->getEncodingValue(FPReg));
1391 }
1392 
emitPad(int64_t Offset)1393 void ARMELFStreamer::emitPad(int64_t Offset) {
1394   // Track the change of the $sp offset
1395   SPOffset -= Offset;
1396 
1397   // To squash multiple .pad directives, we should delay the unwind opcode
1398   // until the .save, .vsave, .handlerdata, or .fnend directives.
1399   PendingOffset -= Offset;
1400 }
1401 
1402 static std::pair<unsigned, unsigned>
collectHWRegs(const MCRegisterInfo & MRI,unsigned Idx,const SmallVectorImpl<unsigned> & RegList,bool IsVector,uint32_t & Mask_)1403 collectHWRegs(const MCRegisterInfo &MRI, unsigned Idx,
1404               const SmallVectorImpl<unsigned> &RegList, bool IsVector,
1405               uint32_t &Mask_) {
1406   uint32_t Mask = 0;
1407   unsigned Count = 0;
1408   while (Idx > 0) {
1409     unsigned Reg = RegList[Idx - 1];
1410     if (Reg == ARM::RA_AUTH_CODE)
1411       break;
1412     Reg = MRI.getEncodingValue(Reg);
1413     assert(Reg < (IsVector ? 32U : 16U) && "Register out of range");
1414     unsigned Bit = (1u << Reg);
1415     if ((Mask & Bit) == 0) {
1416       Mask |= Bit;
1417       ++Count;
1418     }
1419     --Idx;
1420   }
1421 
1422   Mask_ = Mask;
1423   return {Idx, Count};
1424 }
1425 
emitRegSave(const SmallVectorImpl<unsigned> & RegList,bool IsVector)1426 void ARMELFStreamer::emitRegSave(const SmallVectorImpl<unsigned> &RegList,
1427                                  bool IsVector) {
1428   uint32_t Mask;
1429   unsigned Idx, Count;
1430   const MCRegisterInfo &MRI = *getContext().getRegisterInfo();
1431 
1432   // Collect the registers in the register list. Issue unwinding instructions in
1433   // three parts: ordinary hardware registers, return address authentication
1434   // code pseudo register, the rest of the registers. The RA PAC is kept in an
1435   // architectural register (usually r12), but we treat it as a special case in
1436   // order to distinguish between that register containing RA PAC or a general
1437   // value.
1438   Idx = RegList.size();
1439   while (Idx > 0) {
1440     std::tie(Idx, Count) = collectHWRegs(MRI, Idx, RegList, IsVector, Mask);
1441     if (Count) {
1442       // Track the change the $sp offset: For the .save directive, the
1443       // corresponding push instruction will decrease the $sp by (4 * Count).
1444       // For the .vsave directive, the corresponding vpush instruction will
1445       // decrease $sp by (8 * Count).
1446       SPOffset -= Count * (IsVector ? 8 : 4);
1447 
1448       // Emit the opcode
1449       FlushPendingOffset();
1450       if (IsVector)
1451         UnwindOpAsm.EmitVFPRegSave(Mask);
1452       else
1453         UnwindOpAsm.EmitRegSave(Mask);
1454     } else if (Idx > 0 && RegList[Idx - 1] == ARM::RA_AUTH_CODE) {
1455       --Idx;
1456       SPOffset -= 4;
1457       FlushPendingOffset();
1458       UnwindOpAsm.EmitRegSave(0);
1459     }
1460   }
1461 }
1462 
emitUnwindRaw(int64_t Offset,const SmallVectorImpl<uint8_t> & Opcodes)1463 void ARMELFStreamer::emitUnwindRaw(int64_t Offset,
1464                                    const SmallVectorImpl<uint8_t> &Opcodes) {
1465   FlushPendingOffset();
1466   SPOffset = SPOffset - Offset;
1467   UnwindOpAsm.EmitRaw(Opcodes);
1468 }
1469 
1470 namespace llvm {
1471 
createARMTargetAsmStreamer(MCStreamer & S,formatted_raw_ostream & OS,MCInstPrinter * InstPrint,bool isVerboseAsm)1472 MCTargetStreamer *createARMTargetAsmStreamer(MCStreamer &S,
1473                                              formatted_raw_ostream &OS,
1474                                              MCInstPrinter *InstPrint,
1475                                              bool isVerboseAsm) {
1476   return new ARMTargetAsmStreamer(S, OS, *InstPrint, isVerboseAsm);
1477 }
1478 
createARMNullTargetStreamer(MCStreamer & S)1479 MCTargetStreamer *createARMNullTargetStreamer(MCStreamer &S) {
1480   return new ARMTargetStreamer(S);
1481 }
1482 
createARMObjectTargetELFStreamer(MCStreamer & S)1483 MCTargetStreamer *createARMObjectTargetELFStreamer(MCStreamer &S) {
1484   return new ARMTargetELFStreamer(S);
1485 }
1486 
createARMELFStreamer(MCContext & Context,std::unique_ptr<MCAsmBackend> TAB,std::unique_ptr<MCObjectWriter> OW,std::unique_ptr<MCCodeEmitter> Emitter,bool RelaxAll,bool IsThumb,bool IsAndroid)1487 MCELFStreamer *createARMELFStreamer(MCContext &Context,
1488                                     std::unique_ptr<MCAsmBackend> TAB,
1489                                     std::unique_ptr<MCObjectWriter> OW,
1490                                     std::unique_ptr<MCCodeEmitter> Emitter,
1491                                     bool RelaxAll, bool IsThumb,
1492                                     bool IsAndroid) {
1493   ARMELFStreamer *S =
1494       new ARMELFStreamer(Context, std::move(TAB), std::move(OW),
1495                          std::move(Emitter), IsThumb, IsAndroid);
1496   // FIXME: This should eventually end up somewhere else where more
1497   // intelligent flag decisions can be made. For now we are just maintaining
1498   // the status quo for ARM and setting EF_ARM_EABI_VER5 as the default.
1499   S->getAssembler().setELFHeaderEFlags(ELF::EF_ARM_EABI_VER5);
1500 
1501   if (RelaxAll)
1502     S->getAssembler().setRelaxAll(true);
1503   return S;
1504 }
1505 
1506 } // end namespace llvm
1507