1 //===- lib/MC/MCObjectStreamer.cpp - Object File MCStreamer Interface -----===//
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 #include "llvm/MC/MCObjectStreamer.h"
11 #include "llvm/ADT/STLExtras.h"
12 #include "llvm/MC/MCAsmBackend.h"
13 #include "llvm/MC/MCAsmInfo.h"
14 #include "llvm/MC/MCAssembler.h"
15 #include "llvm/MC/MCCodeEmitter.h"
16 #include "llvm/MC/MCCodeView.h"
17 #include "llvm/MC/MCContext.h"
18 #include "llvm/MC/MCDwarf.h"
19 #include "llvm/MC/MCExpr.h"
20 #include "llvm/MC/MCObjectWriter.h"
21 #include "llvm/MC/MCSection.h"
22 #include "llvm/MC/MCSymbol.h"
23 #include "llvm/Support/ErrorHandling.h"
24 #include "llvm/Support/SourceMgr.h"
25 #include "llvm/Support/TargetRegistry.h"
26 using namespace llvm;
27 
28 MCObjectStreamer::MCObjectStreamer(MCContext &Context, MCAsmBackend &TAB,
29                                    raw_pwrite_stream &OS,
30                                    MCCodeEmitter *Emitter_)
31     : MCStreamer(Context),
32       Assembler(new MCAssembler(Context, TAB, *Emitter_,
33                                 *TAB.createObjectWriter(OS))),
34       EmitEHFrame(true), EmitDebugFrame(false) {}
35 
36 MCObjectStreamer::~MCObjectStreamer() {
37   delete &Assembler->getBackend();
38   delete &Assembler->getEmitter();
39   delete &Assembler->getWriter();
40   delete Assembler;
41 }
42 
43 void MCObjectStreamer::flushPendingLabels(MCFragment *F, uint64_t FOffset) {
44   if (PendingLabels.empty())
45     return;
46   if (!F) {
47     F = new MCDataFragment();
48     MCSection *CurSection = getCurrentSectionOnly();
49     CurSection->getFragmentList().insert(CurInsertionPoint, F);
50     F->setParent(CurSection);
51   }
52   for (MCSymbol *Sym : PendingLabels) {
53     Sym->setFragment(F);
54     Sym->setOffset(FOffset);
55   }
56   PendingLabels.clear();
57 }
58 
59 void MCObjectStreamer::emitAbsoluteSymbolDiff(const MCSymbol *Hi,
60                                               const MCSymbol *Lo,
61                                               unsigned Size) {
62   // If not assigned to the same (valid) fragment, fallback.
63   if (!Hi->getFragment() || Hi->getFragment() != Lo->getFragment() ||
64       Hi->isVariable() || Lo->isVariable()) {
65     MCStreamer::emitAbsoluteSymbolDiff(Hi, Lo, Size);
66     return;
67   }
68 
69   EmitIntValue(Hi->getOffset() - Lo->getOffset(), Size);
70 }
71 
72 void MCObjectStreamer::reset() {
73   if (Assembler)
74     Assembler->reset();
75   CurInsertionPoint = MCSection::iterator();
76   EmitEHFrame = true;
77   EmitDebugFrame = false;
78   PendingLabels.clear();
79   MCStreamer::reset();
80 }
81 
82 void MCObjectStreamer::EmitFrames(MCAsmBackend *MAB) {
83   if (!getNumFrameInfos())
84     return;
85 
86   if (EmitEHFrame)
87     MCDwarfFrameEmitter::Emit(*this, MAB, true);
88 
89   if (EmitDebugFrame)
90     MCDwarfFrameEmitter::Emit(*this, MAB, false);
91 }
92 
93 MCFragment *MCObjectStreamer::getCurrentFragment() const {
94   assert(getCurrentSectionOnly() && "No current section!");
95 
96   if (CurInsertionPoint != getCurrentSectionOnly()->getFragmentList().begin())
97     return &*std::prev(CurInsertionPoint);
98 
99   return nullptr;
100 }
101 
102 MCDataFragment *MCObjectStreamer::getOrCreateDataFragment() {
103   MCDataFragment *F = dyn_cast_or_null<MCDataFragment>(getCurrentFragment());
104   // When bundling is enabled, we don't want to add data to a fragment that
105   // already has instructions (see MCELFStreamer::EmitInstToData for details)
106   if (!F || (Assembler->isBundlingEnabled() && !Assembler->getRelaxAll() &&
107              F->hasInstructions())) {
108     F = new MCDataFragment();
109     insert(F);
110   }
111   return F;
112 }
113 
114 void MCObjectStreamer::visitUsedSymbol(const MCSymbol &Sym) {
115   Assembler->registerSymbol(Sym);
116 }
117 
118 void MCObjectStreamer::EmitCFISections(bool EH, bool Debug) {
119   MCStreamer::EmitCFISections(EH, Debug);
120   EmitEHFrame = EH;
121   EmitDebugFrame = Debug;
122 }
123 
124 void MCObjectStreamer::EmitValueImpl(const MCExpr *Value, unsigned Size,
125                                      SMLoc Loc) {
126   MCStreamer::EmitValueImpl(Value, Size, Loc);
127   MCDataFragment *DF = getOrCreateDataFragment();
128   flushPendingLabels(DF, DF->getContents().size());
129 
130   MCCVLineEntry::Make(this);
131   MCDwarfLineEntry::Make(this, getCurrentSectionOnly());
132 
133   // Avoid fixups when possible.
134   int64_t AbsValue;
135   if (Value->evaluateAsAbsolute(AbsValue, getAssembler())) {
136     EmitIntValue(AbsValue, Size);
137     return;
138   }
139   DF->getFixups().push_back(
140       MCFixup::create(DF->getContents().size(), Value,
141                       MCFixup::getKindForSize(Size, false), Loc));
142   DF->getContents().resize(DF->getContents().size() + Size, 0);
143 }
144 
145 void MCObjectStreamer::EmitCFIStartProcImpl(MCDwarfFrameInfo &Frame) {
146   // We need to create a local symbol to avoid relocations.
147   Frame.Begin = getContext().createTempSymbol();
148   EmitLabel(Frame.Begin);
149 }
150 
151 void MCObjectStreamer::EmitCFIEndProcImpl(MCDwarfFrameInfo &Frame) {
152   Frame.End = getContext().createTempSymbol();
153   EmitLabel(Frame.End);
154 }
155 
156 void MCObjectStreamer::EmitLabel(MCSymbol *Symbol) {
157   MCStreamer::EmitLabel(Symbol);
158 
159   getAssembler().registerSymbol(*Symbol);
160 
161   // If there is a current fragment, mark the symbol as pointing into it.
162   // Otherwise queue the label and set its fragment pointer when we emit the
163   // next fragment.
164   auto *F = dyn_cast_or_null<MCDataFragment>(getCurrentFragment());
165   if (F && !(getAssembler().isBundlingEnabled() &&
166              getAssembler().getRelaxAll())) {
167     Symbol->setFragment(F);
168     Symbol->setOffset(F->getContents().size());
169   } else {
170     PendingLabels.push_back(Symbol);
171   }
172 }
173 
174 void MCObjectStreamer::EmitULEB128Value(const MCExpr *Value) {
175   int64_t IntValue;
176   if (Value->evaluateAsAbsolute(IntValue, getAssembler())) {
177     EmitULEB128IntValue(IntValue);
178     return;
179   }
180   insert(new MCLEBFragment(*Value, false));
181 }
182 
183 void MCObjectStreamer::EmitSLEB128Value(const MCExpr *Value) {
184   int64_t IntValue;
185   if (Value->evaluateAsAbsolute(IntValue, getAssembler())) {
186     EmitSLEB128IntValue(IntValue);
187     return;
188   }
189   insert(new MCLEBFragment(*Value, true));
190 }
191 
192 void MCObjectStreamer::EmitWeakReference(MCSymbol *Alias,
193                                          const MCSymbol *Symbol) {
194   report_fatal_error("This file format doesn't support weak aliases.");
195 }
196 
197 void MCObjectStreamer::ChangeSection(MCSection *Section,
198                                      const MCExpr *Subsection) {
199   changeSectionImpl(Section, Subsection);
200 }
201 
202 bool MCObjectStreamer::changeSectionImpl(MCSection *Section,
203                                          const MCExpr *Subsection) {
204   assert(Section && "Cannot switch to a null section!");
205   flushPendingLabels(nullptr);
206 
207   bool Created = getAssembler().registerSection(*Section);
208 
209   int64_t IntSubsection = 0;
210   if (Subsection &&
211       !Subsection->evaluateAsAbsolute(IntSubsection, getAssembler()))
212     report_fatal_error("Cannot evaluate subsection number");
213   if (IntSubsection < 0 || IntSubsection > 8192)
214     report_fatal_error("Subsection number out of range");
215   CurInsertionPoint =
216       Section->getSubsectionInsertionPoint(unsigned(IntSubsection));
217   return Created;
218 }
219 
220 void MCObjectStreamer::EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) {
221   getAssembler().registerSymbol(*Symbol);
222   MCStreamer::EmitAssignment(Symbol, Value);
223 }
224 
225 bool MCObjectStreamer::mayHaveInstructions(MCSection &Sec) const {
226   return Sec.hasInstructions();
227 }
228 
229 void MCObjectStreamer::EmitInstruction(const MCInst &Inst,
230                                        const MCSubtargetInfo &STI) {
231   MCStreamer::EmitInstruction(Inst, STI);
232 
233   MCSection *Sec = getCurrentSectionOnly();
234   Sec->setHasInstructions(true);
235 
236   // Now that a machine instruction has been assembled into this section, make
237   // a line entry for any .loc directive that has been seen.
238   MCCVLineEntry::Make(this);
239   MCDwarfLineEntry::Make(this, getCurrentSectionOnly());
240 
241   // If this instruction doesn't need relaxation, just emit it as data.
242   MCAssembler &Assembler = getAssembler();
243   if (!Assembler.getBackend().mayNeedRelaxation(Inst)) {
244     EmitInstToData(Inst, STI);
245     return;
246   }
247 
248   // Otherwise, relax and emit it as data if either:
249   // - The RelaxAll flag was passed
250   // - Bundling is enabled and this instruction is inside a bundle-locked
251   //   group. We want to emit all such instructions into the same data
252   //   fragment.
253   if (Assembler.getRelaxAll() ||
254       (Assembler.isBundlingEnabled() && Sec->isBundleLocked())) {
255     MCInst Relaxed;
256     getAssembler().getBackend().relaxInstruction(Inst, STI, Relaxed);
257     while (getAssembler().getBackend().mayNeedRelaxation(Relaxed))
258       getAssembler().getBackend().relaxInstruction(Relaxed, STI, Relaxed);
259     EmitInstToData(Relaxed, STI);
260     return;
261   }
262 
263   // Otherwise emit to a separate fragment.
264   EmitInstToFragment(Inst, STI);
265 }
266 
267 void MCObjectStreamer::EmitInstToFragment(const MCInst &Inst,
268                                           const MCSubtargetInfo &STI) {
269   if (getAssembler().getRelaxAll() && getAssembler().isBundlingEnabled())
270     llvm_unreachable("All instructions should have already been relaxed");
271 
272   // Always create a new, separate fragment here, because its size can change
273   // during relaxation.
274   MCRelaxableFragment *IF = new MCRelaxableFragment(Inst, STI);
275   insert(IF);
276 
277   SmallString<128> Code;
278   raw_svector_ostream VecOS(Code);
279   getAssembler().getEmitter().encodeInstruction(Inst, VecOS, IF->getFixups(),
280                                                 STI);
281   IF->getContents().append(Code.begin(), Code.end());
282 }
283 
284 #ifndef NDEBUG
285 static const char *const BundlingNotImplementedMsg =
286   "Aligned bundling is not implemented for this object format";
287 #endif
288 
289 void MCObjectStreamer::EmitBundleAlignMode(unsigned AlignPow2) {
290   llvm_unreachable(BundlingNotImplementedMsg);
291 }
292 
293 void MCObjectStreamer::EmitBundleLock(bool AlignToEnd) {
294   llvm_unreachable(BundlingNotImplementedMsg);
295 }
296 
297 void MCObjectStreamer::EmitBundleUnlock() {
298   llvm_unreachable(BundlingNotImplementedMsg);
299 }
300 
301 void MCObjectStreamer::EmitDwarfLocDirective(unsigned FileNo, unsigned Line,
302                                              unsigned Column, unsigned Flags,
303                                              unsigned Isa,
304                                              unsigned Discriminator,
305                                              StringRef FileName) {
306   // In case we see two .loc directives in a row, make sure the
307   // first one gets a line entry.
308   MCDwarfLineEntry::Make(this, getCurrentSectionOnly());
309 
310   this->MCStreamer::EmitDwarfLocDirective(FileNo, Line, Column, Flags,
311                                           Isa, Discriminator, FileName);
312 }
313 
314 static const MCExpr *buildSymbolDiff(MCObjectStreamer &OS, const MCSymbol *A,
315                                      const MCSymbol *B) {
316   MCContext &Context = OS.getContext();
317   MCSymbolRefExpr::VariantKind Variant = MCSymbolRefExpr::VK_None;
318   const MCExpr *ARef = MCSymbolRefExpr::create(A, Variant, Context);
319   const MCExpr *BRef = MCSymbolRefExpr::create(B, Variant, Context);
320   const MCExpr *AddrDelta =
321       MCBinaryExpr::create(MCBinaryExpr::Sub, ARef, BRef, Context);
322   return AddrDelta;
323 }
324 
325 static void emitDwarfSetLineAddr(MCObjectStreamer &OS,
326                                  MCDwarfLineTableParams Params,
327                                  int64_t LineDelta, const MCSymbol *Label,
328                                  int PointerSize) {
329   // emit the sequence to set the address
330   OS.EmitIntValue(dwarf::DW_LNS_extended_op, 1);
331   OS.EmitULEB128IntValue(PointerSize + 1);
332   OS.EmitIntValue(dwarf::DW_LNE_set_address, 1);
333   OS.EmitSymbolValue(Label, PointerSize);
334 
335   // emit the sequence for the LineDelta (from 1) and a zero address delta.
336   MCDwarfLineAddr::Emit(&OS, Params, LineDelta, 0);
337 }
338 
339 void MCObjectStreamer::EmitDwarfAdvanceLineAddr(int64_t LineDelta,
340                                                 const MCSymbol *LastLabel,
341                                                 const MCSymbol *Label,
342                                                 unsigned PointerSize) {
343   if (!LastLabel) {
344     emitDwarfSetLineAddr(*this, Assembler->getDWARFLinetableParams(), LineDelta,
345                          Label, PointerSize);
346     return;
347   }
348   const MCExpr *AddrDelta = buildSymbolDiff(*this, Label, LastLabel);
349   int64_t Res;
350   if (AddrDelta->evaluateAsAbsolute(Res, getAssembler())) {
351     MCDwarfLineAddr::Emit(this, Assembler->getDWARFLinetableParams(), LineDelta,
352                           Res);
353     return;
354   }
355   insert(new MCDwarfLineAddrFragment(LineDelta, *AddrDelta));
356 }
357 
358 void MCObjectStreamer::EmitDwarfAdvanceFrameAddr(const MCSymbol *LastLabel,
359                                                  const MCSymbol *Label) {
360   const MCExpr *AddrDelta = buildSymbolDiff(*this, Label, LastLabel);
361   int64_t Res;
362   if (AddrDelta->evaluateAsAbsolute(Res, getAssembler())) {
363     MCDwarfFrameEmitter::EmitAdvanceLoc(*this, Res);
364     return;
365   }
366   insert(new MCDwarfCallFrameFragment(*AddrDelta));
367 }
368 
369 void MCObjectStreamer::EmitCVLocDirective(unsigned FunctionId, unsigned FileNo,
370                                           unsigned Line, unsigned Column,
371                                           bool PrologueEnd, bool IsStmt,
372                                           StringRef FileName, SMLoc Loc) {
373   // In case we see two .cv_loc directives in a row, make sure the
374   // first one gets a line entry.
375   MCCVLineEntry::Make(this);
376 
377   this->MCStreamer::EmitCVLocDirective(FunctionId, FileNo, Line, Column,
378                                        PrologueEnd, IsStmt, FileName, Loc);
379 }
380 
381 void MCObjectStreamer::EmitCVLinetableDirective(unsigned FunctionId,
382                                                 const MCSymbol *Begin,
383                                                 const MCSymbol *End) {
384   getContext().getCVContext().emitLineTableForFunction(*this, FunctionId, Begin,
385                                                        End);
386   this->MCStreamer::EmitCVLinetableDirective(FunctionId, Begin, End);
387 }
388 
389 void MCObjectStreamer::EmitCVInlineLinetableDirective(
390     unsigned PrimaryFunctionId, unsigned SourceFileId, unsigned SourceLineNum,
391     const MCSymbol *FnStartSym, const MCSymbol *FnEndSym) {
392   getContext().getCVContext().emitInlineLineTableForFunction(
393       *this, PrimaryFunctionId, SourceFileId, SourceLineNum, FnStartSym,
394       FnEndSym);
395   this->MCStreamer::EmitCVInlineLinetableDirective(
396       PrimaryFunctionId, SourceFileId, SourceLineNum, FnStartSym, FnEndSym);
397 }
398 
399 void MCObjectStreamer::EmitCVDefRangeDirective(
400     ArrayRef<std::pair<const MCSymbol *, const MCSymbol *>> Ranges,
401     StringRef FixedSizePortion) {
402   getContext().getCVContext().emitDefRange(*this, Ranges, FixedSizePortion);
403   this->MCStreamer::EmitCVDefRangeDirective(Ranges, FixedSizePortion);
404 }
405 
406 void MCObjectStreamer::EmitCVStringTableDirective() {
407   getContext().getCVContext().emitStringTable(*this);
408 }
409 void MCObjectStreamer::EmitCVFileChecksumsDirective() {
410   getContext().getCVContext().emitFileChecksums(*this);
411 }
412 
413 
414 void MCObjectStreamer::EmitBytes(StringRef Data) {
415   MCCVLineEntry::Make(this);
416   MCDwarfLineEntry::Make(this, getCurrentSectionOnly());
417   MCDataFragment *DF = getOrCreateDataFragment();
418   flushPendingLabels(DF, DF->getContents().size());
419   DF->getContents().append(Data.begin(), Data.end());
420 }
421 
422 void MCObjectStreamer::EmitValueToAlignment(unsigned ByteAlignment,
423                                             int64_t Value,
424                                             unsigned ValueSize,
425                                             unsigned MaxBytesToEmit) {
426   if (MaxBytesToEmit == 0)
427     MaxBytesToEmit = ByteAlignment;
428   insert(new MCAlignFragment(ByteAlignment, Value, ValueSize, MaxBytesToEmit));
429 
430   // Update the maximum alignment on the current section if necessary.
431   MCSection *CurSec = getCurrentSectionOnly();
432   if (ByteAlignment > CurSec->getAlignment())
433     CurSec->setAlignment(ByteAlignment);
434 }
435 
436 void MCObjectStreamer::EmitCodeAlignment(unsigned ByteAlignment,
437                                          unsigned MaxBytesToEmit) {
438   EmitValueToAlignment(ByteAlignment, 0, 1, MaxBytesToEmit);
439   cast<MCAlignFragment>(getCurrentFragment())->setEmitNops(true);
440 }
441 
442 void MCObjectStreamer::emitValueToOffset(const MCExpr *Offset,
443                                          unsigned char Value,
444                                          SMLoc Loc) {
445   insert(new MCOrgFragment(*Offset, Value, Loc));
446 }
447 
448 // Associate DTPRel32 fixup with data and resize data area
449 void MCObjectStreamer::EmitDTPRel32Value(const MCExpr *Value) {
450   MCDataFragment *DF = getOrCreateDataFragment();
451   flushPendingLabels(DF, DF->getContents().size());
452 
453   DF->getFixups().push_back(MCFixup::create(DF->getContents().size(),
454                                             Value, FK_DTPRel_4));
455   DF->getContents().resize(DF->getContents().size() + 4, 0);
456 }
457 
458 // Associate DTPRel64 fixup with data and resize data area
459 void MCObjectStreamer::EmitDTPRel64Value(const MCExpr *Value) {
460   MCDataFragment *DF = getOrCreateDataFragment();
461   flushPendingLabels(DF, DF->getContents().size());
462 
463   DF->getFixups().push_back(MCFixup::create(DF->getContents().size(),
464                                             Value, FK_DTPRel_8));
465   DF->getContents().resize(DF->getContents().size() + 8, 0);
466 }
467 
468 // Associate TPRel32 fixup with data and resize data area
469 void MCObjectStreamer::EmitTPRel32Value(const MCExpr *Value) {
470   MCDataFragment *DF = getOrCreateDataFragment();
471   flushPendingLabels(DF, DF->getContents().size());
472 
473   DF->getFixups().push_back(MCFixup::create(DF->getContents().size(),
474                                             Value, FK_TPRel_4));
475   DF->getContents().resize(DF->getContents().size() + 4, 0);
476 }
477 
478 // Associate TPRel64 fixup with data and resize data area
479 void MCObjectStreamer::EmitTPRel64Value(const MCExpr *Value) {
480   MCDataFragment *DF = getOrCreateDataFragment();
481   flushPendingLabels(DF, DF->getContents().size());
482 
483   DF->getFixups().push_back(MCFixup::create(DF->getContents().size(),
484                                             Value, FK_TPRel_8));
485   DF->getContents().resize(DF->getContents().size() + 8, 0);
486 }
487 
488 // Associate GPRel32 fixup with data and resize data area
489 void MCObjectStreamer::EmitGPRel32Value(const MCExpr *Value) {
490   MCDataFragment *DF = getOrCreateDataFragment();
491   flushPendingLabels(DF, DF->getContents().size());
492 
493   DF->getFixups().push_back(MCFixup::create(DF->getContents().size(),
494                                             Value, FK_GPRel_4));
495   DF->getContents().resize(DF->getContents().size() + 4, 0);
496 }
497 
498 // Associate GPRel64 fixup with data and resize data area
499 void MCObjectStreamer::EmitGPRel64Value(const MCExpr *Value) {
500   MCDataFragment *DF = getOrCreateDataFragment();
501   flushPendingLabels(DF, DF->getContents().size());
502 
503   DF->getFixups().push_back(MCFixup::create(DF->getContents().size(),
504                                             Value, FK_GPRel_4));
505   DF->getContents().resize(DF->getContents().size() + 8, 0);
506 }
507 
508 bool MCObjectStreamer::EmitRelocDirective(const MCExpr &Offset, StringRef Name,
509                                           const MCExpr *Expr, SMLoc Loc) {
510   int64_t OffsetValue;
511   if (!Offset.evaluateAsAbsolute(OffsetValue))
512     llvm_unreachable("Offset is not absolute");
513 
514   if (OffsetValue < 0)
515     llvm_unreachable("Offset is negative");
516 
517   MCDataFragment *DF = getOrCreateDataFragment();
518   flushPendingLabels(DF, DF->getContents().size());
519 
520   Optional<MCFixupKind> MaybeKind = Assembler->getBackend().getFixupKind(Name);
521   if (!MaybeKind.hasValue())
522     return true;
523 
524   MCFixupKind Kind = *MaybeKind;
525 
526   if (Expr == nullptr)
527     Expr =
528         MCSymbolRefExpr::create(getContext().createTempSymbol(), getContext());
529   DF->getFixups().push_back(MCFixup::create(OffsetValue, Expr, Kind, Loc));
530   return false;
531 }
532 
533 void MCObjectStreamer::emitFill(uint64_t NumBytes, uint8_t FillValue) {
534   assert(getCurrentSectionOnly() && "need a section");
535   insert(new MCFillFragment(FillValue, NumBytes));
536 }
537 
538 void MCObjectStreamer::emitFill(const MCExpr &NumBytes, uint64_t FillValue,
539                                 SMLoc Loc) {
540   MCDataFragment *DF = getOrCreateDataFragment();
541   flushPendingLabels(DF, DF->getContents().size());
542 
543   int64_t IntNumBytes;
544   if (!NumBytes.evaluateAsAbsolute(IntNumBytes, getAssembler())) {
545     getContext().reportError(Loc, "expected absolute expression");
546     return;
547   }
548 
549   if (IntNumBytes <= 0) {
550     getContext().reportError(Loc, "invalid number of bytes");
551     return;
552   }
553 
554   emitFill(IntNumBytes, FillValue);
555 }
556 
557 void MCObjectStreamer::emitFill(const MCExpr &NumValues, int64_t Size,
558                                 int64_t Expr, SMLoc Loc) {
559   int64_t IntNumValues;
560   if (!NumValues.evaluateAsAbsolute(IntNumValues, getAssembler())) {
561     getContext().reportError(Loc, "expected absolute expression");
562     return;
563   }
564 
565   if (IntNumValues < 0) {
566     getContext().getSourceManager()->PrintMessage(
567         Loc, SourceMgr::DK_Warning,
568         "'.fill' directive with negative repeat count has no effect");
569     return;
570   }
571 
572   MCStreamer::emitFill(IntNumValues, Size, Expr);
573 }
574 
575 void MCObjectStreamer::FinishImpl() {
576   // If we are generating dwarf for assembly source files dump out the sections.
577   if (getContext().getGenDwarfForAssembly())
578     MCGenDwarfInfo::Emit(this);
579 
580   // Dump out the dwarf file & directory tables and line tables.
581   MCDwarfLineTable::Emit(this, getAssembler().getDWARFLinetableParams());
582 
583   flushPendingLabels(nullptr);
584   getAssembler().Finish();
585 }
586