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1 //===- lib/MC/MCELFStreamer.cpp - ELF Object Output -----------------------===//
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 ELF .o object files.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "llvm/MC/MCELFStreamer.h"
15 #include "llvm/ADT/SmallPtrSet.h"
16 #include "llvm/ADT/STLExtras.h"
17 #include "llvm/MC/MCAssembler.h"
18 #include "llvm/MC/MCCodeEmitter.h"
19 #include "llvm/MC/MCContext.h"
20 #include "llvm/MC/MCELF.h"
21 #include "llvm/MC/MCELFSymbolFlags.h"
22 #include "llvm/MC/MCExpr.h"
23 #include "llvm/MC/MCInst.h"
24 #include "llvm/MC/MCObjectStreamer.h"
25 #include "llvm/MC/MCSection.h"
26 #include "llvm/MC/MCSectionELF.h"
27 #include "llvm/MC/MCSymbol.h"
28 #include "llvm/MC/MCValue.h"
29 #include "llvm/Support/Debug.h"
30 #include "llvm/Support/ELF.h"
31 #include "llvm/Support/ErrorHandling.h"
32 #include "llvm/Support/raw_ostream.h"
33 
34 using namespace llvm;
35 
36 
SetSection(StringRef Section,unsigned Type,unsigned Flags,SectionKind Kind)37 inline void MCELFStreamer::SetSection(StringRef Section, unsigned Type,
38                                       unsigned Flags, SectionKind Kind) {
39   SwitchSection(getContext().getELFSection(Section, Type, Flags, Kind));
40 }
41 
SetSectionData()42 inline void MCELFStreamer::SetSectionData() {
43   SetSection(".data",
44              ELF::SHT_PROGBITS,
45              ELF::SHF_WRITE | ELF::SHF_ALLOC,
46              SectionKind::getDataRel());
47   EmitCodeAlignment(4, 0);
48 }
49 
SetSectionText()50 inline void MCELFStreamer::SetSectionText() {
51   SetSection(".text",
52              ELF::SHT_PROGBITS,
53              ELF::SHF_EXECINSTR | ELF::SHF_ALLOC,
54              SectionKind::getText());
55   EmitCodeAlignment(4, 0);
56 }
57 
SetSectionBss()58 inline void MCELFStreamer::SetSectionBss() {
59   SetSection(".bss",
60              ELF::SHT_NOBITS,
61              ELF::SHF_WRITE | ELF::SHF_ALLOC,
62              SectionKind::getBSS());
63   EmitCodeAlignment(4, 0);
64 }
65 
~MCELFStreamer()66 MCELFStreamer::~MCELFStreamer() {
67 }
68 
InitToTextSection()69 void MCELFStreamer::InitToTextSection() {
70   SetSectionText();
71 }
72 
InitSections()73 void MCELFStreamer::InitSections() {
74   // This emulates the same behavior of GNU as. This makes it easier
75   // to compare the output as the major sections are in the same order.
76   SetSectionText();
77   SetSectionData();
78   SetSectionBss();
79   SetSectionText();
80 }
81 
EmitLabel(MCSymbol * Symbol)82 void MCELFStreamer::EmitLabel(MCSymbol *Symbol) {
83   assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
84 
85   MCObjectStreamer::EmitLabel(Symbol);
86 
87   const MCSectionELF &Section =
88     static_cast<const MCSectionELF&>(Symbol->getSection());
89   MCSymbolData &SD = getAssembler().getSymbolData(*Symbol);
90   if (Section.getFlags() & ELF::SHF_TLS)
91     MCELF::SetType(SD, ELF::STT_TLS);
92 }
93 
EmitDebugLabel(MCSymbol * Symbol)94 void MCELFStreamer::EmitDebugLabel(MCSymbol *Symbol) {
95   EmitLabel(Symbol);
96 }
97 
EmitAssemblerFlag(MCAssemblerFlag Flag)98 void MCELFStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) {
99   switch (Flag) {
100   case MCAF_SyntaxUnified: return; // no-op here.
101   case MCAF_Code16: return; // Change parsing mode; no-op here.
102   case MCAF_Code32: return; // Change parsing mode; no-op here.
103   case MCAF_Code64: return; // Change parsing mode; no-op here.
104   case MCAF_SubsectionsViaSymbols:
105     getAssembler().setSubsectionsViaSymbols(true);
106     return;
107   }
108 
109   llvm_unreachable("invalid assembler flag!");
110 }
111 
ChangeSection(const MCSection * Section,const MCExpr * Subsection)112 void MCELFStreamer::ChangeSection(const MCSection *Section,
113                                   const MCExpr *Subsection) {
114   MCSectionData *CurSection = getCurrentSectionData();
115   if (CurSection && CurSection->isBundleLocked())
116     report_fatal_error("Unterminated .bundle_lock when changing a section");
117   const MCSymbol *Grp = static_cast<const MCSectionELF *>(Section)->getGroup();
118   if (Grp)
119     getAssembler().getOrCreateSymbolData(*Grp);
120   this->MCObjectStreamer::ChangeSection(Section, Subsection);
121 }
122 
EmitWeakReference(MCSymbol * Alias,const MCSymbol * Symbol)123 void MCELFStreamer::EmitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol) {
124   getAssembler().getOrCreateSymbolData(*Symbol);
125   MCSymbolData &AliasSD = getAssembler().getOrCreateSymbolData(*Alias);
126   AliasSD.setFlags(AliasSD.getFlags() | ELF_Other_Weakref);
127   const MCExpr *Value = MCSymbolRefExpr::Create(Symbol, getContext());
128   Alias->setVariableValue(Value);
129 }
130 
131 // When GNU as encounters more than one .type declaration for an object it seems
132 // to use a mechanism similar to the one below to decide which type is actually
133 // used in the object file.  The greater of T1 and T2 is selected based on the
134 // following ordering:
135 //  STT_NOTYPE < STT_OBJECT < STT_FUNC < STT_GNU_IFUNC < STT_TLS < anything else
136 // If neither T1 < T2 nor T2 < T1 according to this ordering, use T2 (the user
137 // provided type).
CombineSymbolTypes(unsigned T1,unsigned T2)138 static unsigned CombineSymbolTypes(unsigned T1, unsigned T2) {
139   unsigned TypeOrdering[] = {ELF::STT_NOTYPE, ELF::STT_OBJECT, ELF::STT_FUNC,
140                              ELF::STT_GNU_IFUNC, ELF::STT_TLS};
141   for (unsigned i = 0; i != array_lengthof(TypeOrdering); ++i) {
142     if (T1 == TypeOrdering[i])
143       return T2;
144     if (T2 == TypeOrdering[i])
145       return T1;
146   }
147 
148   return T2;
149 }
150 
EmitSymbolAttribute(MCSymbol * Symbol,MCSymbolAttr Attribute)151 void MCELFStreamer::EmitSymbolAttribute(MCSymbol *Symbol,
152                                           MCSymbolAttr Attribute) {
153   // Indirect symbols are handled differently, to match how 'as' handles
154   // them. This makes writing matching .o files easier.
155   if (Attribute == MCSA_IndirectSymbol) {
156     // Note that we intentionally cannot use the symbol data here; this is
157     // important for matching the string table that 'as' generates.
158     IndirectSymbolData ISD;
159     ISD.Symbol = Symbol;
160     ISD.SectionData = getCurrentSectionData();
161     getAssembler().getIndirectSymbols().push_back(ISD);
162     return;
163   }
164 
165   // Adding a symbol attribute always introduces the symbol, note that an
166   // important side effect of calling getOrCreateSymbolData here is to register
167   // the symbol with the assembler.
168   MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
169 
170   // The implementation of symbol attributes is designed to match 'as', but it
171   // leaves much to desired. It doesn't really make sense to arbitrarily add and
172   // remove flags, but 'as' allows this (in particular, see .desc).
173   //
174   // In the future it might be worth trying to make these operations more well
175   // defined.
176   switch (Attribute) {
177   case MCSA_LazyReference:
178   case MCSA_Reference:
179   case MCSA_SymbolResolver:
180   case MCSA_PrivateExtern:
181   case MCSA_WeakDefinition:
182   case MCSA_WeakDefAutoPrivate:
183   case MCSA_Invalid:
184   case MCSA_IndirectSymbol:
185     llvm_unreachable("Invalid symbol attribute for ELF!");
186 
187   case MCSA_NoDeadStrip:
188   case MCSA_ELF_TypeGnuUniqueObject:
189     // Ignore for now.
190     break;
191 
192   case MCSA_Global:
193     MCELF::SetBinding(SD, ELF::STB_GLOBAL);
194     SD.setExternal(true);
195     BindingExplicitlySet.insert(Symbol);
196     break;
197 
198   case MCSA_WeakReference:
199   case MCSA_Weak:
200     MCELF::SetBinding(SD, ELF::STB_WEAK);
201     SD.setExternal(true);
202     BindingExplicitlySet.insert(Symbol);
203     break;
204 
205   case MCSA_Local:
206     MCELF::SetBinding(SD, ELF::STB_LOCAL);
207     SD.setExternal(false);
208     BindingExplicitlySet.insert(Symbol);
209     break;
210 
211   case MCSA_ELF_TypeFunction:
212     MCELF::SetType(SD, CombineSymbolTypes(MCELF::GetType(SD),
213                                           ELF::STT_FUNC));
214     break;
215 
216   case MCSA_ELF_TypeIndFunction:
217     MCELF::SetType(SD, CombineSymbolTypes(MCELF::GetType(SD),
218                                           ELF::STT_GNU_IFUNC));
219     break;
220 
221   case MCSA_ELF_TypeObject:
222     MCELF::SetType(SD, CombineSymbolTypes(MCELF::GetType(SD),
223                                           ELF::STT_OBJECT));
224     break;
225 
226   case MCSA_ELF_TypeTLS:
227     MCELF::SetType(SD, CombineSymbolTypes(MCELF::GetType(SD),
228                                           ELF::STT_TLS));
229     break;
230 
231   case MCSA_ELF_TypeCommon:
232     // TODO: Emit these as a common symbol.
233     MCELF::SetType(SD, CombineSymbolTypes(MCELF::GetType(SD),
234                                           ELF::STT_OBJECT));
235     break;
236 
237   case MCSA_ELF_TypeNoType:
238     MCELF::SetType(SD, CombineSymbolTypes(MCELF::GetType(SD),
239                                           ELF::STT_NOTYPE));
240     break;
241 
242   case MCSA_Protected:
243     MCELF::SetVisibility(SD, ELF::STV_PROTECTED);
244     break;
245 
246   case MCSA_Hidden:
247     MCELF::SetVisibility(SD, ELF::STV_HIDDEN);
248     break;
249 
250   case MCSA_Internal:
251     MCELF::SetVisibility(SD, ELF::STV_INTERNAL);
252     break;
253   }
254 }
255 
EmitCommonSymbol(MCSymbol * Symbol,uint64_t Size,unsigned ByteAlignment)256 void MCELFStreamer::EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
257                                        unsigned ByteAlignment) {
258   MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
259 
260   if (!BindingExplicitlySet.count(Symbol)) {
261     MCELF::SetBinding(SD, ELF::STB_GLOBAL);
262     SD.setExternal(true);
263   }
264 
265   MCELF::SetType(SD, ELF::STT_OBJECT);
266 
267   if (MCELF::GetBinding(SD) == ELF_STB_Local) {
268     const MCSection *Section = getAssembler().getContext().getELFSection(".bss",
269                                                          ELF::SHT_NOBITS,
270                                                          ELF::SHF_WRITE |
271                                                          ELF::SHF_ALLOC,
272                                                          SectionKind::getBSS());
273     Symbol->setSection(*Section);
274 
275     struct LocalCommon L = {&SD, Size, ByteAlignment};
276     LocalCommons.push_back(L);
277   } else {
278     SD.setCommon(Size, ByteAlignment);
279   }
280 
281   SD.setSize(MCConstantExpr::Create(Size, getContext()));
282 }
283 
EmitELFSize(MCSymbol * Symbol,const MCExpr * Value)284 void MCELFStreamer::EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) {
285   MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
286   SD.setSize(Value);
287 }
288 
EmitLocalCommonSymbol(MCSymbol * Symbol,uint64_t Size,unsigned ByteAlignment)289 void MCELFStreamer::EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
290                                           unsigned ByteAlignment) {
291   // FIXME: Should this be caught and done earlier?
292   MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
293   MCELF::SetBinding(SD, ELF::STB_LOCAL);
294   SD.setExternal(false);
295   BindingExplicitlySet.insert(Symbol);
296   EmitCommonSymbol(Symbol, Size, ByteAlignment);
297 }
298 
EmitValueImpl(const MCExpr * Value,unsigned Size)299 void MCELFStreamer::EmitValueImpl(const MCExpr *Value, unsigned Size) {
300   if (getCurrentSectionData()->isBundleLocked())
301     report_fatal_error("Emitting values inside a locked bundle is forbidden");
302   fixSymbolsInTLSFixups(Value);
303   MCObjectStreamer::EmitValueImpl(Value, Size);
304 }
305 
EmitValueToAlignment(unsigned ByteAlignment,int64_t Value,unsigned ValueSize,unsigned MaxBytesToEmit)306 void MCELFStreamer::EmitValueToAlignment(unsigned ByteAlignment,
307                                          int64_t Value,
308                                          unsigned ValueSize,
309                                          unsigned MaxBytesToEmit) {
310   if (getCurrentSectionData()->isBundleLocked())
311     report_fatal_error("Emitting values inside a locked bundle is forbidden");
312   MCObjectStreamer::EmitValueToAlignment(ByteAlignment, Value,
313                                          ValueSize, MaxBytesToEmit);
314 }
315 
316 
317 // Add a symbol for the file name of this module. This is the second
318 // entry in the module's symbol table (the first being the null symbol).
EmitFileDirective(StringRef Filename)319 void MCELFStreamer::EmitFileDirective(StringRef Filename) {
320   MCSymbol *Symbol = getAssembler().getContext().GetOrCreateSymbol(Filename);
321   Symbol->setSection(*getCurrentSection().first);
322   Symbol->setAbsolute();
323 
324   MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
325 
326   SD.setFlags(ELF_STT_File | ELF_STB_Local | ELF_STV_Default);
327 }
328 
fixSymbolsInTLSFixups(const MCExpr * expr)329 void  MCELFStreamer::fixSymbolsInTLSFixups(const MCExpr *expr) {
330   switch (expr->getKind()) {
331   case MCExpr::Target:
332     cast<MCTargetExpr>(expr)->fixELFSymbolsInTLSFixups(getAssembler());
333     break;
334   case MCExpr::Constant:
335     break;
336 
337   case MCExpr::Binary: {
338     const MCBinaryExpr *be = cast<MCBinaryExpr>(expr);
339     fixSymbolsInTLSFixups(be->getLHS());
340     fixSymbolsInTLSFixups(be->getRHS());
341     break;
342   }
343 
344   case MCExpr::SymbolRef: {
345     const MCSymbolRefExpr &symRef = *cast<MCSymbolRefExpr>(expr);
346     switch (symRef.getKind()) {
347     default:
348       return;
349     case MCSymbolRefExpr::VK_GOTTPOFF:
350     case MCSymbolRefExpr::VK_INDNTPOFF:
351     case MCSymbolRefExpr::VK_NTPOFF:
352     case MCSymbolRefExpr::VK_GOTNTPOFF:
353     case MCSymbolRefExpr::VK_TLSGD:
354     case MCSymbolRefExpr::VK_TLSLD:
355     case MCSymbolRefExpr::VK_TLSLDM:
356     case MCSymbolRefExpr::VK_TPOFF:
357     case MCSymbolRefExpr::VK_DTPOFF:
358     case MCSymbolRefExpr::VK_ARM_TLSGD:
359     case MCSymbolRefExpr::VK_ARM_TPOFF:
360     case MCSymbolRefExpr::VK_ARM_GOTTPOFF:
361     case MCSymbolRefExpr::VK_Mips_TLSGD:
362     case MCSymbolRefExpr::VK_Mips_GOTTPREL:
363     case MCSymbolRefExpr::VK_Mips_TPREL_HI:
364     case MCSymbolRefExpr::VK_Mips_TPREL_LO:
365     case MCSymbolRefExpr::VK_PPC_DTPMOD:
366     case MCSymbolRefExpr::VK_PPC_TPREL:
367     case MCSymbolRefExpr::VK_PPC_TPREL_LO:
368     case MCSymbolRefExpr::VK_PPC_TPREL_HI:
369     case MCSymbolRefExpr::VK_PPC_TPREL_HA:
370     case MCSymbolRefExpr::VK_PPC_TPREL_HIGHER:
371     case MCSymbolRefExpr::VK_PPC_TPREL_HIGHERA:
372     case MCSymbolRefExpr::VK_PPC_TPREL_HIGHEST:
373     case MCSymbolRefExpr::VK_PPC_TPREL_HIGHESTA:
374     case MCSymbolRefExpr::VK_PPC_DTPREL:
375     case MCSymbolRefExpr::VK_PPC_DTPREL_LO:
376     case MCSymbolRefExpr::VK_PPC_DTPREL_HI:
377     case MCSymbolRefExpr::VK_PPC_DTPREL_HA:
378     case MCSymbolRefExpr::VK_PPC_DTPREL_HIGHER:
379     case MCSymbolRefExpr::VK_PPC_DTPREL_HIGHERA:
380     case MCSymbolRefExpr::VK_PPC_DTPREL_HIGHEST:
381     case MCSymbolRefExpr::VK_PPC_DTPREL_HIGHESTA:
382     case MCSymbolRefExpr::VK_PPC_GOT_TPREL:
383     case MCSymbolRefExpr::VK_PPC_GOT_TPREL_LO:
384     case MCSymbolRefExpr::VK_PPC_GOT_TPREL_HI:
385     case MCSymbolRefExpr::VK_PPC_GOT_TPREL_HA:
386     case MCSymbolRefExpr::VK_PPC_GOT_DTPREL:
387     case MCSymbolRefExpr::VK_PPC_GOT_DTPREL_LO:
388     case MCSymbolRefExpr::VK_PPC_GOT_DTPREL_HI:
389     case MCSymbolRefExpr::VK_PPC_GOT_DTPREL_HA:
390     case MCSymbolRefExpr::VK_PPC_TLS:
391     case MCSymbolRefExpr::VK_PPC_GOT_TLSGD:
392     case MCSymbolRefExpr::VK_PPC_GOT_TLSGD_LO:
393     case MCSymbolRefExpr::VK_PPC_GOT_TLSGD_HI:
394     case MCSymbolRefExpr::VK_PPC_GOT_TLSGD_HA:
395     case MCSymbolRefExpr::VK_PPC_TLSGD:
396     case MCSymbolRefExpr::VK_PPC_GOT_TLSLD:
397     case MCSymbolRefExpr::VK_PPC_GOT_TLSLD_LO:
398     case MCSymbolRefExpr::VK_PPC_GOT_TLSLD_HI:
399     case MCSymbolRefExpr::VK_PPC_GOT_TLSLD_HA:
400     case MCSymbolRefExpr::VK_PPC_TLSLD:
401       break;
402     }
403     MCSymbolData &SD = getAssembler().getOrCreateSymbolData(symRef.getSymbol());
404     MCELF::SetType(SD, ELF::STT_TLS);
405     break;
406   }
407 
408   case MCExpr::Unary:
409     fixSymbolsInTLSFixups(cast<MCUnaryExpr>(expr)->getSubExpr());
410     break;
411   }
412 }
413 
EmitInstToFragment(const MCInst & Inst)414 void MCELFStreamer::EmitInstToFragment(const MCInst &Inst) {
415   this->MCObjectStreamer::EmitInstToFragment(Inst);
416   MCRelaxableFragment &F = *cast<MCRelaxableFragment>(getCurrentFragment());
417 
418   for (unsigned i = 0, e = F.getFixups().size(); i != e; ++i)
419     fixSymbolsInTLSFixups(F.getFixups()[i].getValue());
420 }
421 
EmitInstToData(const MCInst & Inst)422 void MCELFStreamer::EmitInstToData(const MCInst &Inst) {
423   MCAssembler &Assembler = getAssembler();
424   SmallVector<MCFixup, 4> Fixups;
425   SmallString<256> Code;
426   raw_svector_ostream VecOS(Code);
427   Assembler.getEmitter().EncodeInstruction(Inst, VecOS, Fixups);
428   VecOS.flush();
429 
430   for (unsigned i = 0, e = Fixups.size(); i != e; ++i)
431     fixSymbolsInTLSFixups(Fixups[i].getValue());
432 
433   // There are several possibilities here:
434   //
435   // If bundling is disabled, append the encoded instruction to the current data
436   // fragment (or create a new such fragment if the current fragment is not a
437   // data fragment).
438   //
439   // If bundling is enabled:
440   // - If we're not in a bundle-locked group, emit the instruction into a
441   //   fragment of its own. If there are no fixups registered for the
442   //   instruction, emit a MCCompactEncodedInstFragment. Otherwise, emit a
443   //   MCDataFragment.
444   // - If we're in a bundle-locked group, append the instruction to the current
445   //   data fragment because we want all the instructions in a group to get into
446   //   the same fragment. Be careful not to do that for the first instruction in
447   //   the group, though.
448   MCDataFragment *DF;
449 
450   if (Assembler.isBundlingEnabled()) {
451     MCSectionData *SD = getCurrentSectionData();
452     if (SD->isBundleLocked() && !SD->isBundleGroupBeforeFirstInst())
453       // If we are bundle-locked, we re-use the current fragment.
454       // The bundle-locking directive ensures this is a new data fragment.
455       DF = cast<MCDataFragment>(getCurrentFragment());
456     else if (!SD->isBundleLocked() && Fixups.size() == 0) {
457       // Optimize memory usage by emitting the instruction to a
458       // MCCompactEncodedInstFragment when not in a bundle-locked group and
459       // there are no fixups registered.
460       MCCompactEncodedInstFragment *CEIF = new MCCompactEncodedInstFragment();
461       insert(CEIF);
462       CEIF->getContents().append(Code.begin(), Code.end());
463       return;
464     } else {
465       DF = new MCDataFragment();
466       insert(DF);
467       if (SD->getBundleLockState() == MCSectionData::BundleLockedAlignToEnd) {
468         // If this is a new fragment created for a bundle-locked group, and the
469         // group was marked as "align_to_end", set a flag in the fragment.
470         DF->setAlignToBundleEnd(true);
471       }
472     }
473 
474     // We're now emitting an instruction in a bundle group, so this flag has
475     // to be turned off.
476     SD->setBundleGroupBeforeFirstInst(false);
477   } else {
478     DF = getOrCreateDataFragment();
479   }
480 
481   // Add the fixups and data.
482   for (unsigned i = 0, e = Fixups.size(); i != e; ++i) {
483     Fixups[i].setOffset(Fixups[i].getOffset() + DF->getContents().size());
484     DF->getFixups().push_back(Fixups[i]);
485   }
486   DF->setHasInstructions(true);
487   DF->getContents().append(Code.begin(), Code.end());
488 }
489 
EmitBundleAlignMode(unsigned AlignPow2)490 void MCELFStreamer::EmitBundleAlignMode(unsigned AlignPow2) {
491   assert(AlignPow2 <= 30 && "Invalid bundle alignment");
492   MCAssembler &Assembler = getAssembler();
493   if (Assembler.getBundleAlignSize() == 0 && AlignPow2 > 0)
494     Assembler.setBundleAlignSize(1 << AlignPow2);
495   else
496     report_fatal_error(".bundle_align_mode should be only set once per file");
497 }
498 
EmitBundleLock(bool AlignToEnd)499 void MCELFStreamer::EmitBundleLock(bool AlignToEnd) {
500   MCSectionData *SD = getCurrentSectionData();
501 
502   // Sanity checks
503   //
504   if (!getAssembler().isBundlingEnabled())
505     report_fatal_error(".bundle_lock forbidden when bundling is disabled");
506   else if (SD->isBundleLocked())
507     report_fatal_error("Nesting of .bundle_lock is forbidden");
508 
509   SD->setBundleLockState(AlignToEnd ? MCSectionData::BundleLockedAlignToEnd :
510                                       MCSectionData::BundleLocked);
511   SD->setBundleGroupBeforeFirstInst(true);
512 }
513 
EmitBundleUnlock()514 void MCELFStreamer::EmitBundleUnlock() {
515   MCSectionData *SD = getCurrentSectionData();
516 
517   // Sanity checks
518   if (!getAssembler().isBundlingEnabled())
519     report_fatal_error(".bundle_unlock forbidden when bundling is disabled");
520   else if (!SD->isBundleLocked())
521     report_fatal_error(".bundle_unlock without matching lock");
522   else if (SD->isBundleGroupBeforeFirstInst())
523     report_fatal_error("Empty bundle-locked group is forbidden");
524 
525   SD->setBundleLockState(MCSectionData::NotBundleLocked);
526 }
527 
FinishImpl()528 void MCELFStreamer::FinishImpl() {
529   EmitFrames(true);
530 
531   for (std::vector<LocalCommon>::const_iterator i = LocalCommons.begin(),
532                                                 e = LocalCommons.end();
533        i != e; ++i) {
534     MCSymbolData *SD = i->SD;
535     uint64_t Size = i->Size;
536     unsigned ByteAlignment = i->ByteAlignment;
537     const MCSymbol &Symbol = SD->getSymbol();
538     const MCSection &Section = Symbol.getSection();
539 
540     MCSectionData &SectData = getAssembler().getOrCreateSectionData(Section);
541     new MCAlignFragment(ByteAlignment, 0, 1, ByteAlignment, &SectData);
542 
543     MCFragment *F = new MCFillFragment(0, 0, Size, &SectData);
544     SD->setFragment(F);
545 
546     // Update the maximum alignment of the section if necessary.
547     if (ByteAlignment > SectData.getAlignment())
548       SectData.setAlignment(ByteAlignment);
549   }
550 
551   this->MCObjectStreamer::FinishImpl();
552 }
EmitTCEntry(const MCSymbol & S)553 void MCELFStreamer::EmitTCEntry(const MCSymbol &S) {
554   // Creates a R_PPC64_TOC relocation
555   MCObjectStreamer::EmitSymbolValue(&S, 8);
556 }
557 
createELFStreamer(MCContext & Context,MCAsmBackend & MAB,raw_ostream & OS,MCCodeEmitter * CE,bool RelaxAll,bool NoExecStack)558 MCStreamer *llvm::createELFStreamer(MCContext &Context, MCAsmBackend &MAB,
559                                     raw_ostream &OS, MCCodeEmitter *CE,
560                                     bool RelaxAll, bool NoExecStack) {
561   MCELFStreamer *S = new MCELFStreamer(Context, MAB, OS, CE);
562   if (RelaxAll)
563     S->getAssembler().setRelaxAll(true);
564   if (NoExecStack)
565     S->getAssembler().setNoExecStack(true);
566   return S;
567 }
568 
EmitThumbFunc(MCSymbol * Func)569 void MCELFStreamer::EmitThumbFunc(MCSymbol *Func) {
570   llvm_unreachable("Generic ELF doesn't support this directive");
571 }
572 
getOrCreateSymbolData(MCSymbol * Symbol)573 MCSymbolData &MCELFStreamer::getOrCreateSymbolData(MCSymbol *Symbol) {
574   return getAssembler().getOrCreateSymbolData(*Symbol);
575 }
576 
EmitSymbolDesc(MCSymbol * Symbol,unsigned DescValue)577 void MCELFStreamer::EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {
578   llvm_unreachable("ELF doesn't support this directive");
579 }
580 
BeginCOFFSymbolDef(const MCSymbol * Symbol)581 void MCELFStreamer::BeginCOFFSymbolDef(const MCSymbol *Symbol) {
582   llvm_unreachable("ELF doesn't support this directive");
583 }
584 
EmitCOFFSymbolStorageClass(int StorageClass)585 void MCELFStreamer::EmitCOFFSymbolStorageClass(int StorageClass) {
586   llvm_unreachable("ELF doesn't support this directive");
587 }
588 
EmitCOFFSymbolType(int Type)589 void MCELFStreamer::EmitCOFFSymbolType(int Type) {
590   llvm_unreachable("ELF doesn't support this directive");
591 }
592 
EndCOFFSymbolDef()593 void MCELFStreamer::EndCOFFSymbolDef() {
594   llvm_unreachable("ELF doesn't support this directive");
595 }
596 
EmitZerofill(const MCSection * Section,MCSymbol * Symbol,uint64_t Size,unsigned ByteAlignment)597 void MCELFStreamer::EmitZerofill(const MCSection *Section, MCSymbol *Symbol,
598                                  uint64_t Size, unsigned ByteAlignment) {
599   llvm_unreachable("ELF doesn't support this directive");
600 }
601 
EmitTBSSSymbol(const MCSection * Section,MCSymbol * Symbol,uint64_t Size,unsigned ByteAlignment)602 void MCELFStreamer::EmitTBSSSymbol(const MCSection *Section, MCSymbol *Symbol,
603                                    uint64_t Size, unsigned ByteAlignment) {
604   llvm_unreachable("ELF doesn't support this directive");
605 }
606