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 "MCELF.h"
15 #include "llvm/ADT/SmallPtrSet.h"
16 #include "llvm/MC/MCAssembler.h"
17 #include "llvm/MC/MCCodeEmitter.h"
18 #include "llvm/MC/MCContext.h"
19 #include "llvm/MC/MCSectionELF.h"
20 #include "llvm/MC/MCStreamer.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/MCSymbol.h"
27 #include "llvm/MC/MCValue.h"
28 #include "llvm/MC/MCAsmBackend.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 namespace {
37 class MCELFStreamer : public MCObjectStreamer {
38 public:
MCELFStreamer(MCContext & Context,MCAsmBackend & TAB,raw_ostream & OS,MCCodeEmitter * Emitter)39 MCELFStreamer(MCContext &Context, MCAsmBackend &TAB,
40 raw_ostream &OS, MCCodeEmitter *Emitter)
41 : MCObjectStreamer(Context, TAB, OS, Emitter) {}
42
MCELFStreamer(MCContext & Context,MCAsmBackend & TAB,raw_ostream & OS,MCCodeEmitter * Emitter,MCAssembler * Assembler)43 MCELFStreamer(MCContext &Context, MCAsmBackend &TAB,
44 raw_ostream &OS, MCCodeEmitter *Emitter,
45 MCAssembler *Assembler)
46 : MCObjectStreamer(Context, TAB, OS, Emitter, Assembler) {}
47
48
~MCELFStreamer()49 ~MCELFStreamer() {}
50
51 /// @name MCStreamer Interface
52 /// @{
53
54 virtual void InitSections();
55 virtual void ChangeSection(const MCSection *Section);
56 virtual void EmitLabel(MCSymbol *Symbol);
57 virtual void EmitAssemblerFlag(MCAssemblerFlag Flag);
58 virtual void EmitThumbFunc(MCSymbol *Func);
59 virtual void EmitAssignment(MCSymbol *Symbol, const MCExpr *Value);
60 virtual void EmitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol);
61 virtual void EmitSymbolAttribute(MCSymbol *Symbol, MCSymbolAttr Attribute);
EmitSymbolDesc(MCSymbol * Symbol,unsigned DescValue)62 virtual void EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {
63 llvm_unreachable("ELF doesn't support this directive");
64 }
65 virtual void EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
66 unsigned ByteAlignment);
BeginCOFFSymbolDef(const MCSymbol * Symbol)67 virtual void BeginCOFFSymbolDef(const MCSymbol *Symbol) {
68 llvm_unreachable("ELF doesn't support this directive");
69 }
70
EmitCOFFSymbolStorageClass(int StorageClass)71 virtual void EmitCOFFSymbolStorageClass(int StorageClass) {
72 llvm_unreachable("ELF doesn't support this directive");
73 }
74
EmitCOFFSymbolType(int Type)75 virtual void EmitCOFFSymbolType(int Type) {
76 llvm_unreachable("ELF doesn't support this directive");
77 }
78
EndCOFFSymbolDef()79 virtual void EndCOFFSymbolDef() {
80 llvm_unreachable("ELF doesn't support this directive");
81 }
82
EmitELFSize(MCSymbol * Symbol,const MCExpr * Value)83 virtual void EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) {
84 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
85 SD.setSize(Value);
86 }
87
88 virtual void EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
89 unsigned ByteAlignment);
90
EmitZerofill(const MCSection * Section,MCSymbol * Symbol=0,unsigned Size=0,unsigned ByteAlignment=0)91 virtual void EmitZerofill(const MCSection *Section, MCSymbol *Symbol = 0,
92 unsigned Size = 0, unsigned ByteAlignment = 0) {
93 llvm_unreachable("ELF doesn't support this directive");
94 }
EmitTBSSSymbol(const MCSection * Section,MCSymbol * Symbol,uint64_t Size,unsigned ByteAlignment=0)95 virtual void EmitTBSSSymbol(const MCSection *Section, MCSymbol *Symbol,
96 uint64_t Size, unsigned ByteAlignment = 0) {
97 llvm_unreachable("ELF doesn't support this directive");
98 }
99 virtual void EmitBytes(StringRef Data, unsigned AddrSpace);
100 virtual void EmitValueToAlignment(unsigned ByteAlignment, int64_t Value = 0,
101 unsigned ValueSize = 1,
102 unsigned MaxBytesToEmit = 0);
103 virtual void EmitCodeAlignment(unsigned ByteAlignment,
104 unsigned MaxBytesToEmit = 0);
105 virtual void EmitValueImpl(const MCExpr *Value, unsigned Size,
106 unsigned AddrSpace);
107
108 virtual void EmitFileDirective(StringRef Filename);
109
110 virtual void FinishImpl();
111
112 private:
113 virtual void EmitInstToFragment(const MCInst &Inst);
114 virtual void EmitInstToData(const MCInst &Inst);
115
116 void fixSymbolsInTLSFixups(const MCExpr *expr);
117
118 struct LocalCommon {
119 MCSymbolData *SD;
120 uint64_t Size;
121 unsigned ByteAlignment;
122 };
123 std::vector<LocalCommon> LocalCommons;
124
125 SmallPtrSet<MCSymbol *, 16> BindingExplicitlySet;
126 /// @}
SetSection(StringRef Section,unsigned Type,unsigned Flags,SectionKind Kind)127 void SetSection(StringRef Section, unsigned Type, unsigned Flags,
128 SectionKind Kind) {
129 SwitchSection(getContext().getELFSection(Section, Type, Flags, Kind));
130 }
131
SetSectionData()132 void SetSectionData() {
133 SetSection(".data", ELF::SHT_PROGBITS,
134 ELF::SHF_WRITE |ELF::SHF_ALLOC,
135 SectionKind::getDataRel());
136 EmitCodeAlignment(4, 0);
137 }
SetSectionText()138 void SetSectionText() {
139 SetSection(".text", ELF::SHT_PROGBITS,
140 ELF::SHF_EXECINSTR |
141 ELF::SHF_ALLOC, SectionKind::getText());
142 EmitCodeAlignment(4, 0);
143 }
SetSectionBss()144 void SetSectionBss() {
145 SetSection(".bss", ELF::SHT_NOBITS,
146 ELF::SHF_WRITE |
147 ELF::SHF_ALLOC, SectionKind::getBSS());
148 EmitCodeAlignment(4, 0);
149 }
150 };
151 }
152
InitSections()153 void MCELFStreamer::InitSections() {
154 // This emulates the same behavior of GNU as. This makes it easier
155 // to compare the output as the major sections are in the same order.
156 SetSectionText();
157 SetSectionData();
158 SetSectionBss();
159 SetSectionText();
160 }
161
EmitLabel(MCSymbol * Symbol)162 void MCELFStreamer::EmitLabel(MCSymbol *Symbol) {
163 assert(Symbol->isUndefined() && "Cannot define a symbol twice!");
164
165 MCObjectStreamer::EmitLabel(Symbol);
166
167 const MCSectionELF &Section =
168 static_cast<const MCSectionELF&>(Symbol->getSection());
169 MCSymbolData &SD = getAssembler().getSymbolData(*Symbol);
170 if (Section.getFlags() & ELF::SHF_TLS)
171 MCELF::SetType(SD, ELF::STT_TLS);
172 }
173
EmitAssemblerFlag(MCAssemblerFlag Flag)174 void MCELFStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) {
175 switch (Flag) {
176 case MCAF_SyntaxUnified: return; // no-op here.
177 case MCAF_Code16: return; // Change parsing mode; no-op here.
178 case MCAF_Code32: return; // Change parsing mode; no-op here.
179 case MCAF_Code64: return; // Change parsing mode; no-op here.
180 case MCAF_SubsectionsViaSymbols:
181 getAssembler().setSubsectionsViaSymbols(true);
182 return;
183 }
184
185 llvm_unreachable("invalid assembler flag!");
186 }
187
EmitThumbFunc(MCSymbol * Func)188 void MCELFStreamer::EmitThumbFunc(MCSymbol *Func) {
189 // FIXME: Anything needed here to flag the function as thumb?
190
191 getAssembler().setIsThumbFunc(Func);
192
193 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Func);
194 SD.setFlags(SD.getFlags() | ELF_Other_ThumbFunc);
195 }
196
EmitAssignment(MCSymbol * Symbol,const MCExpr * Value)197 void MCELFStreamer::EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) {
198 // TODO: This is exactly the same as WinCOFFStreamer. Consider merging into
199 // MCObjectStreamer.
200 // FIXME: Lift context changes into super class.
201 getAssembler().getOrCreateSymbolData(*Symbol);
202 Symbol->setVariableValue(AddValueSymbols(Value));
203 }
204
ChangeSection(const MCSection * Section)205 void MCELFStreamer::ChangeSection(const MCSection *Section) {
206 const MCSymbol *Grp = static_cast<const MCSectionELF *>(Section)->getGroup();
207 if (Grp)
208 getAssembler().getOrCreateSymbolData(*Grp);
209 this->MCObjectStreamer::ChangeSection(Section);
210 }
211
EmitWeakReference(MCSymbol * Alias,const MCSymbol * Symbol)212 void MCELFStreamer::EmitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol) {
213 getAssembler().getOrCreateSymbolData(*Symbol);
214 MCSymbolData &AliasSD = getAssembler().getOrCreateSymbolData(*Alias);
215 AliasSD.setFlags(AliasSD.getFlags() | ELF_Other_Weakref);
216 const MCExpr *Value = MCSymbolRefExpr::Create(Symbol, getContext());
217 Alias->setVariableValue(Value);
218 }
219
EmitSymbolAttribute(MCSymbol * Symbol,MCSymbolAttr Attribute)220 void MCELFStreamer::EmitSymbolAttribute(MCSymbol *Symbol,
221 MCSymbolAttr Attribute) {
222 // Indirect symbols are handled differently, to match how 'as' handles
223 // them. This makes writing matching .o files easier.
224 if (Attribute == MCSA_IndirectSymbol) {
225 // Note that we intentionally cannot use the symbol data here; this is
226 // important for matching the string table that 'as' generates.
227 IndirectSymbolData ISD;
228 ISD.Symbol = Symbol;
229 ISD.SectionData = getCurrentSectionData();
230 getAssembler().getIndirectSymbols().push_back(ISD);
231 return;
232 }
233
234 // Adding a symbol attribute always introduces the symbol, note that an
235 // important side effect of calling getOrCreateSymbolData here is to register
236 // the symbol with the assembler.
237 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
238
239 // The implementation of symbol attributes is designed to match 'as', but it
240 // leaves much to desired. It doesn't really make sense to arbitrarily add and
241 // remove flags, but 'as' allows this (in particular, see .desc).
242 //
243 // In the future it might be worth trying to make these operations more well
244 // defined.
245 switch (Attribute) {
246 case MCSA_LazyReference:
247 case MCSA_Reference:
248 case MCSA_NoDeadStrip:
249 case MCSA_SymbolResolver:
250 case MCSA_PrivateExtern:
251 case MCSA_WeakDefinition:
252 case MCSA_WeakDefAutoPrivate:
253 case MCSA_Invalid:
254 case MCSA_IndirectSymbol:
255 llvm_unreachable("Invalid symbol attribute for ELF!");
256
257 case MCSA_ELF_TypeGnuUniqueObject:
258 // Ignore for now.
259 break;
260
261 case MCSA_Global:
262 MCELF::SetBinding(SD, ELF::STB_GLOBAL);
263 SD.setExternal(true);
264 BindingExplicitlySet.insert(Symbol);
265 break;
266
267 case MCSA_WeakReference:
268 case MCSA_Weak:
269 MCELF::SetBinding(SD, ELF::STB_WEAK);
270 SD.setExternal(true);
271 BindingExplicitlySet.insert(Symbol);
272 break;
273
274 case MCSA_Local:
275 MCELF::SetBinding(SD, ELF::STB_LOCAL);
276 SD.setExternal(false);
277 BindingExplicitlySet.insert(Symbol);
278 break;
279
280 case MCSA_ELF_TypeFunction:
281 MCELF::SetType(SD, ELF::STT_FUNC);
282 break;
283
284 case MCSA_ELF_TypeIndFunction:
285 MCELF::SetType(SD, ELF::STT_GNU_IFUNC);
286 break;
287
288 case MCSA_ELF_TypeObject:
289 MCELF::SetType(SD, ELF::STT_OBJECT);
290 break;
291
292 case MCSA_ELF_TypeTLS:
293 MCELF::SetType(SD, ELF::STT_TLS);
294 break;
295
296 case MCSA_ELF_TypeCommon:
297 MCELF::SetType(SD, ELF::STT_COMMON);
298 break;
299
300 case MCSA_ELF_TypeNoType:
301 MCELF::SetType(SD, ELF::STT_NOTYPE);
302 break;
303
304 case MCSA_Protected:
305 MCELF::SetVisibility(SD, ELF::STV_PROTECTED);
306 break;
307
308 case MCSA_Hidden:
309 MCELF::SetVisibility(SD, ELF::STV_HIDDEN);
310 break;
311
312 case MCSA_Internal:
313 MCELF::SetVisibility(SD, ELF::STV_INTERNAL);
314 break;
315 }
316 }
317
EmitCommonSymbol(MCSymbol * Symbol,uint64_t Size,unsigned ByteAlignment)318 void MCELFStreamer::EmitCommonSymbol(MCSymbol *Symbol, uint64_t Size,
319 unsigned ByteAlignment) {
320 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
321
322 if (!BindingExplicitlySet.count(Symbol)) {
323 MCELF::SetBinding(SD, ELF::STB_GLOBAL);
324 SD.setExternal(true);
325 }
326
327 MCELF::SetType(SD, ELF::STT_OBJECT);
328
329 if (MCELF::GetBinding(SD) == ELF_STB_Local) {
330 const MCSection *Section = getAssembler().getContext().getELFSection(".bss",
331 ELF::SHT_NOBITS,
332 ELF::SHF_WRITE |
333 ELF::SHF_ALLOC,
334 SectionKind::getBSS());
335 Symbol->setSection(*Section);
336
337 struct LocalCommon L = {&SD, Size, ByteAlignment};
338 LocalCommons.push_back(L);
339 } else {
340 SD.setCommon(Size, ByteAlignment);
341 }
342
343 SD.setSize(MCConstantExpr::Create(Size, getContext()));
344 }
345
EmitLocalCommonSymbol(MCSymbol * Symbol,uint64_t Size,unsigned ByteAlignment)346 void MCELFStreamer::EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
347 unsigned ByteAlignment) {
348 // FIXME: Should this be caught and done earlier?
349 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
350 MCELF::SetBinding(SD, ELF::STB_LOCAL);
351 SD.setExternal(false);
352 BindingExplicitlySet.insert(Symbol);
353 EmitCommonSymbol(Symbol, Size, ByteAlignment);
354 }
355
EmitBytes(StringRef Data,unsigned AddrSpace)356 void MCELFStreamer::EmitBytes(StringRef Data, unsigned AddrSpace) {
357 // TODO: This is exactly the same as WinCOFFStreamer. Consider merging into
358 // MCObjectStreamer.
359 getOrCreateDataFragment()->getContents().append(Data.begin(), Data.end());
360 }
361
EmitValueToAlignment(unsigned ByteAlignment,int64_t Value,unsigned ValueSize,unsigned MaxBytesToEmit)362 void MCELFStreamer::EmitValueToAlignment(unsigned ByteAlignment,
363 int64_t Value, unsigned ValueSize,
364 unsigned MaxBytesToEmit) {
365 // TODO: This is exactly the same as WinCOFFStreamer. Consider merging into
366 // MCObjectStreamer.
367 if (MaxBytesToEmit == 0)
368 MaxBytesToEmit = ByteAlignment;
369 new MCAlignFragment(ByteAlignment, Value, ValueSize, MaxBytesToEmit,
370 getCurrentSectionData());
371
372 // Update the maximum alignment on the current section if necessary.
373 if (ByteAlignment > getCurrentSectionData()->getAlignment())
374 getCurrentSectionData()->setAlignment(ByteAlignment);
375 }
376
EmitCodeAlignment(unsigned ByteAlignment,unsigned MaxBytesToEmit)377 void MCELFStreamer::EmitCodeAlignment(unsigned ByteAlignment,
378 unsigned MaxBytesToEmit) {
379 // TODO: This is exactly the same as WinCOFFStreamer. Consider merging into
380 // MCObjectStreamer.
381 if (MaxBytesToEmit == 0)
382 MaxBytesToEmit = ByteAlignment;
383 MCAlignFragment *F = new MCAlignFragment(ByteAlignment, 0, 1, MaxBytesToEmit,
384 getCurrentSectionData());
385 F->setEmitNops(true);
386
387 // Update the maximum alignment on the current section if necessary.
388 if (ByteAlignment > getCurrentSectionData()->getAlignment())
389 getCurrentSectionData()->setAlignment(ByteAlignment);
390 }
391
EmitValueImpl(const MCExpr * Value,unsigned Size,unsigned AddrSpace)392 void MCELFStreamer::EmitValueImpl(const MCExpr *Value, unsigned Size,
393 unsigned AddrSpace) {
394 fixSymbolsInTLSFixups(Value);
395 MCObjectStreamer::EmitValueImpl(Value, Size, AddrSpace);
396 }
397
398
399 // Add a symbol for the file name of this module. This is the second
400 // entry in the module's symbol table (the first being the null symbol).
EmitFileDirective(StringRef Filename)401 void MCELFStreamer::EmitFileDirective(StringRef Filename) {
402 MCSymbol *Symbol = getAssembler().getContext().GetOrCreateSymbol(Filename);
403 Symbol->setSection(*getCurrentSection());
404 Symbol->setAbsolute();
405
406 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(*Symbol);
407
408 SD.setFlags(ELF_STT_File | ELF_STB_Local | ELF_STV_Default);
409 }
410
fixSymbolsInTLSFixups(const MCExpr * expr)411 void MCELFStreamer::fixSymbolsInTLSFixups(const MCExpr *expr) {
412 switch (expr->getKind()) {
413 case MCExpr::Target: llvm_unreachable("Can't handle target exprs yet!");
414 case MCExpr::Constant:
415 break;
416
417 case MCExpr::Binary: {
418 const MCBinaryExpr *be = cast<MCBinaryExpr>(expr);
419 fixSymbolsInTLSFixups(be->getLHS());
420 fixSymbolsInTLSFixups(be->getRHS());
421 break;
422 }
423
424 case MCExpr::SymbolRef: {
425 const MCSymbolRefExpr &symRef = *cast<MCSymbolRefExpr>(expr);
426 switch (symRef.getKind()) {
427 default:
428 return;
429 case MCSymbolRefExpr::VK_GOTTPOFF:
430 case MCSymbolRefExpr::VK_INDNTPOFF:
431 case MCSymbolRefExpr::VK_NTPOFF:
432 case MCSymbolRefExpr::VK_GOTNTPOFF:
433 case MCSymbolRefExpr::VK_TLSGD:
434 case MCSymbolRefExpr::VK_TLSLD:
435 case MCSymbolRefExpr::VK_TLSLDM:
436 case MCSymbolRefExpr::VK_TPOFF:
437 case MCSymbolRefExpr::VK_DTPOFF:
438 case MCSymbolRefExpr::VK_ARM_TLSGD:
439 case MCSymbolRefExpr::VK_ARM_TPOFF:
440 case MCSymbolRefExpr::VK_ARM_GOTTPOFF:
441 case MCSymbolRefExpr::VK_Mips_TLSGD:
442 case MCSymbolRefExpr::VK_Mips_GOTTPREL:
443 case MCSymbolRefExpr::VK_Mips_TPREL_HI:
444 case MCSymbolRefExpr::VK_Mips_TPREL_LO:
445 break;
446 }
447 MCSymbolData &SD = getAssembler().getOrCreateSymbolData(symRef.getSymbol());
448 MCELF::SetType(SD, ELF::STT_TLS);
449 break;
450 }
451
452 case MCExpr::Unary:
453 fixSymbolsInTLSFixups(cast<MCUnaryExpr>(expr)->getSubExpr());
454 break;
455 }
456 }
457
EmitInstToFragment(const MCInst & Inst)458 void MCELFStreamer::EmitInstToFragment(const MCInst &Inst) {
459 this->MCObjectStreamer::EmitInstToFragment(Inst);
460 MCInstFragment &F = *cast<MCInstFragment>(getCurrentFragment());
461
462 for (unsigned i = 0, e = F.getFixups().size(); i != e; ++i)
463 fixSymbolsInTLSFixups(F.getFixups()[i].getValue());
464 }
465
EmitInstToData(const MCInst & Inst)466 void MCELFStreamer::EmitInstToData(const MCInst &Inst) {
467 MCDataFragment *DF = getOrCreateDataFragment();
468
469 SmallVector<MCFixup, 4> Fixups;
470 SmallString<256> Code;
471 raw_svector_ostream VecOS(Code);
472 getAssembler().getEmitter().EncodeInstruction(Inst, VecOS, Fixups);
473 VecOS.flush();
474
475 for (unsigned i = 0, e = Fixups.size(); i != e; ++i)
476 fixSymbolsInTLSFixups(Fixups[i].getValue());
477
478 // Add the fixups and data.
479 for (unsigned i = 0, e = Fixups.size(); i != e; ++i) {
480 Fixups[i].setOffset(Fixups[i].getOffset() + DF->getContents().size());
481 DF->addFixup(Fixups[i]);
482 }
483 DF->getContents().append(Code.begin(), Code.end());
484 }
485
FinishImpl()486 void MCELFStreamer::FinishImpl() {
487 EmitFrames(true);
488
489 for (std::vector<LocalCommon>::const_iterator i = LocalCommons.begin(),
490 e = LocalCommons.end();
491 i != e; ++i) {
492 MCSymbolData *SD = i->SD;
493 uint64_t Size = i->Size;
494 unsigned ByteAlignment = i->ByteAlignment;
495 const MCSymbol &Symbol = SD->getSymbol();
496 const MCSection &Section = Symbol.getSection();
497
498 MCSectionData &SectData = getAssembler().getOrCreateSectionData(Section);
499 new MCAlignFragment(ByteAlignment, 0, 1, ByteAlignment, &SectData);
500
501 MCFragment *F = new MCFillFragment(0, 0, Size, &SectData);
502 SD->setFragment(F);
503
504 // Update the maximum alignment of the section if necessary.
505 if (ByteAlignment > SectData.getAlignment())
506 SectData.setAlignment(ByteAlignment);
507 }
508
509 this->MCObjectStreamer::FinishImpl();
510 }
511
createELFStreamer(MCContext & Context,MCAsmBackend & MAB,raw_ostream & OS,MCCodeEmitter * CE,bool RelaxAll,bool NoExecStack)512 MCStreamer *llvm::createELFStreamer(MCContext &Context, MCAsmBackend &MAB,
513 raw_ostream &OS, MCCodeEmitter *CE,
514 bool RelaxAll, bool NoExecStack) {
515 MCELFStreamer *S = new MCELFStreamer(Context, MAB, OS, CE);
516 if (RelaxAll)
517 S->getAssembler().setRelaxAll(true);
518 if (NoExecStack)
519 S->getAssembler().setNoExecStack(true);
520 return S;
521 }
522