1 //===- lib/MC/MCStreamer.cpp - Streaming Machine Code 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 #include "llvm/MC/MCStreamer.h"
11 #include "llvm/ADT/SmallString.h"
12 #include "llvm/ADT/Twine.h"
13 #include "llvm/MC/MCAsmBackend.h"
14 #include "llvm/MC/MCAsmInfo.h"
15 #include "llvm/MC/MCContext.h"
16 #include "llvm/MC/MCExpr.h"
17 #include "llvm/MC/MCInst.h"
18 #include "llvm/MC/MCInstPrinter.h"
19 #include "llvm/MC/MCObjectFileInfo.h"
20 #include "llvm/MC/MCObjectWriter.h"
21 #include "llvm/MC/MCSection.h"
22 #include "llvm/MC/MCSectionCOFF.h"
23 #include "llvm/MC/MCSymbol.h"
24 #include "llvm/MC/MCWin64EH.h"
25 #include "llvm/Support/COFF.h"
26 #include "llvm/Support/ErrorHandling.h"
27 #include "llvm/Support/LEB128.h"
28 #include "llvm/Support/raw_ostream.h"
29 #include <cstdlib>
30 using namespace llvm;
31 
32 // Pin the vtables to this file.
33 MCTargetStreamer::~MCTargetStreamer() {}
34 
35 MCTargetStreamer::MCTargetStreamer(MCStreamer &S) : Streamer(S) {
36   S.setTargetStreamer(this);
37 }
38 
39 void MCTargetStreamer::emitLabel(MCSymbol *Symbol) {}
40 
41 void MCTargetStreamer::finish() {}
42 
43 void MCTargetStreamer::emitAssignment(MCSymbol *Symbol, const MCExpr *Value) {}
44 
45 MCStreamer::MCStreamer(MCContext &Ctx)
46     : Context(Ctx), CurrentWinFrameInfo(nullptr) {
47   SectionStack.push_back(std::pair<MCSectionSubPair, MCSectionSubPair>());
48 }
49 
50 MCStreamer::~MCStreamer() {
51   for (unsigned i = 0; i < getNumWinFrameInfos(); ++i)
52     delete WinFrameInfos[i];
53 }
54 
55 void MCStreamer::reset() {
56   DwarfFrameInfos.clear();
57   for (unsigned i = 0; i < getNumWinFrameInfos(); ++i)
58     delete WinFrameInfos[i];
59   WinFrameInfos.clear();
60   CurrentWinFrameInfo = nullptr;
61   SymbolOrdering.clear();
62   SectionStack.clear();
63   SectionStack.push_back(std::pair<MCSectionSubPair, MCSectionSubPair>());
64 }
65 
66 raw_ostream &MCStreamer::GetCommentOS() {
67   // By default, discard comments.
68   return nulls();
69 }
70 
71 void MCStreamer::emitRawComment(const Twine &T, bool TabPrefix) {}
72 
73 void MCStreamer::generateCompactUnwindEncodings(MCAsmBackend *MAB) {
74   for (auto &FI : DwarfFrameInfos)
75     FI.CompactUnwindEncoding =
76         (MAB ? MAB->generateCompactUnwindEncoding(FI.Instructions) : 0);
77 }
78 
79 /// EmitIntValue - Special case of EmitValue that avoids the client having to
80 /// pass in a MCExpr for constant integers.
81 void MCStreamer::EmitIntValue(uint64_t Value, unsigned Size) {
82   assert(1 <= Size && Size <= 8 && "Invalid size");
83   assert((isUIntN(8 * Size, Value) || isIntN(8 * Size, Value)) &&
84          "Invalid size");
85   char buf[8];
86   const bool isLittleEndian = Context.getAsmInfo()->isLittleEndian();
87   for (unsigned i = 0; i != Size; ++i) {
88     unsigned index = isLittleEndian ? i : (Size - i - 1);
89     buf[i] = uint8_t(Value >> (index * 8));
90   }
91   EmitBytes(StringRef(buf, Size));
92 }
93 
94 /// EmitULEB128Value - Special case of EmitULEB128Value that avoids the
95 /// client having to pass in a MCExpr for constant integers.
96 void MCStreamer::EmitULEB128IntValue(uint64_t Value, unsigned Padding) {
97   SmallString<128> Tmp;
98   raw_svector_ostream OSE(Tmp);
99   encodeULEB128(Value, OSE, Padding);
100   EmitBytes(OSE.str());
101 }
102 
103 /// EmitSLEB128Value - Special case of EmitSLEB128Value that avoids the
104 /// client having to pass in a MCExpr for constant integers.
105 void MCStreamer::EmitSLEB128IntValue(int64_t Value) {
106   SmallString<128> Tmp;
107   raw_svector_ostream OSE(Tmp);
108   encodeSLEB128(Value, OSE);
109   EmitBytes(OSE.str());
110 }
111 
112 void MCStreamer::EmitValue(const MCExpr *Value, unsigned Size, SMLoc Loc) {
113   EmitValueImpl(Value, Size, Loc);
114 }
115 
116 void MCStreamer::EmitSymbolValue(const MCSymbol *Sym, unsigned Size,
117                                  bool IsSectionRelative) {
118   assert((!IsSectionRelative || Size == 4) &&
119          "SectionRelative value requires 4-bytes");
120 
121   if (!IsSectionRelative)
122     EmitValueImpl(MCSymbolRefExpr::create(Sym, getContext()), Size);
123   else
124     EmitCOFFSecRel32(Sym);
125 }
126 
127 void MCStreamer::EmitGPRel64Value(const MCExpr *Value) {
128   report_fatal_error("unsupported directive in streamer");
129 }
130 
131 void MCStreamer::EmitGPRel32Value(const MCExpr *Value) {
132   report_fatal_error("unsupported directive in streamer");
133 }
134 
135 /// Emit NumBytes bytes worth of the value specified by FillValue.
136 /// This implements directives such as '.space'.
137 void MCStreamer::emitFill(uint64_t NumBytes, uint8_t FillValue) {
138   for (uint64_t i = 0, e = NumBytes; i != e; ++i)
139     EmitIntValue(FillValue, 1);
140 }
141 
142 void MCStreamer::emitFill(uint64_t NumValues, int64_t Size, int64_t Expr) {
143   int64_t NonZeroSize = Size > 4 ? 4 : Size;
144   Expr &= ~0ULL >> (64 - NonZeroSize * 8);
145   for (uint64_t i = 0, e = NumValues; i != e; ++i) {
146     EmitIntValue(Expr, NonZeroSize);
147     if (NonZeroSize < Size)
148       EmitIntValue(0, Size - NonZeroSize);
149   }
150 }
151 
152 /// The implementation in this class just redirects to emitFill.
153 void MCStreamer::EmitZeros(uint64_t NumBytes) {
154   emitFill(NumBytes, 0);
155 }
156 
157 unsigned MCStreamer::EmitDwarfFileDirective(unsigned FileNo,
158                                             StringRef Directory,
159                                             StringRef Filename, unsigned CUID) {
160   return getContext().getDwarfFile(Directory, Filename, FileNo, CUID);
161 }
162 
163 void MCStreamer::EmitDwarfLocDirective(unsigned FileNo, unsigned Line,
164                                        unsigned Column, unsigned Flags,
165                                        unsigned Isa,
166                                        unsigned Discriminator,
167                                        StringRef FileName) {
168   getContext().setCurrentDwarfLoc(FileNo, Line, Column, Flags, Isa,
169                                   Discriminator);
170 }
171 
172 MCSymbol *MCStreamer::getDwarfLineTableSymbol(unsigned CUID) {
173   MCDwarfLineTable &Table = getContext().getMCDwarfLineTable(CUID);
174   if (!Table.getLabel()) {
175     StringRef Prefix = Context.getAsmInfo()->getPrivateGlobalPrefix();
176     Table.setLabel(
177         Context.getOrCreateSymbol(Prefix + "line_table_start" + Twine(CUID)));
178   }
179   return Table.getLabel();
180 }
181 
182 MCDwarfFrameInfo *MCStreamer::getCurrentDwarfFrameInfo() {
183   if (DwarfFrameInfos.empty())
184     return nullptr;
185   return &DwarfFrameInfos.back();
186 }
187 
188 bool MCStreamer::hasUnfinishedDwarfFrameInfo() {
189   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
190   return CurFrame && !CurFrame->End;
191 }
192 
193 void MCStreamer::EnsureValidDwarfFrame() {
194   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
195   if (!CurFrame || CurFrame->End)
196     report_fatal_error("No open frame");
197 }
198 
199 unsigned MCStreamer::EmitCVFileDirective(unsigned FileNo, StringRef Filename) {
200   return getContext().getCVFile(Filename, FileNo);
201 }
202 
203 void MCStreamer::EmitCVLocDirective(unsigned FunctionId, unsigned FileNo,
204                                     unsigned Line, unsigned Column,
205                                     bool PrologueEnd, bool IsStmt,
206                                     StringRef FileName) {
207   getContext().setCurrentCVLoc(FunctionId, FileNo, Line, Column, PrologueEnd,
208                                IsStmt);
209 }
210 
211 void MCStreamer::EmitCVLinetableDirective(unsigned FunctionId,
212                                           const MCSymbol *Begin,
213                                           const MCSymbol *End) {}
214 
215 void MCStreamer::EmitCVInlineLinetableDirective(
216     unsigned PrimaryFunctionId, unsigned SourceFileId, unsigned SourceLineNum,
217     const MCSymbol *FnStartSym, const MCSymbol *FnEndSym,
218     ArrayRef<unsigned> SecondaryFunctionIds) {}
219 
220 void MCStreamer::EmitCVDefRangeDirective(
221     ArrayRef<std::pair<const MCSymbol *, const MCSymbol *>> Ranges,
222     StringRef FixedSizePortion) {}
223 
224 void MCStreamer::EmitEHSymAttributes(const MCSymbol *Symbol,
225                                      MCSymbol *EHSymbol) {
226 }
227 
228 void MCStreamer::InitSections(bool NoExecStack) {
229   SwitchSection(getContext().getObjectFileInfo()->getTextSection());
230 }
231 
232 void MCStreamer::AssignFragment(MCSymbol *Symbol, MCFragment *Fragment) {
233   assert(Fragment);
234   Symbol->setFragment(Fragment);
235 
236   // As we emit symbols into a section, track the order so that they can
237   // be sorted upon later. Zero is reserved to mean 'unemitted'.
238   SymbolOrdering[Symbol] = 1 + SymbolOrdering.size();
239 }
240 
241 void MCStreamer::EmitLabel(MCSymbol *Symbol) {
242   assert(!Symbol->isVariable() && "Cannot emit a variable symbol!");
243   assert(getCurrentSection().first && "Cannot emit before setting section!");
244   assert(!Symbol->getFragment() && "Unexpected fragment on symbol data!");
245   Symbol->setFragment(&getCurrentSectionOnly()->getDummyFragment());
246 
247   MCTargetStreamer *TS = getTargetStreamer();
248   if (TS)
249     TS->emitLabel(Symbol);
250 }
251 
252 void MCStreamer::EmitCFISections(bool EH, bool Debug) {
253   assert(EH || Debug);
254 }
255 
256 void MCStreamer::EmitCFIStartProc(bool IsSimple) {
257   if (hasUnfinishedDwarfFrameInfo())
258     report_fatal_error("Starting a frame before finishing the previous one!");
259 
260   MCDwarfFrameInfo Frame;
261   Frame.IsSimple = IsSimple;
262   EmitCFIStartProcImpl(Frame);
263 
264   const MCAsmInfo* MAI = Context.getAsmInfo();
265   if (MAI) {
266     for (const MCCFIInstruction& Inst : MAI->getInitialFrameState()) {
267       if (Inst.getOperation() == MCCFIInstruction::OpDefCfa ||
268           Inst.getOperation() == MCCFIInstruction::OpDefCfaRegister) {
269         Frame.CurrentCfaRegister = Inst.getRegister();
270       }
271     }
272   }
273 
274   DwarfFrameInfos.push_back(Frame);
275 }
276 
277 void MCStreamer::EmitCFIStartProcImpl(MCDwarfFrameInfo &Frame) {
278 }
279 
280 void MCStreamer::EmitCFIEndProc() {
281   EnsureValidDwarfFrame();
282   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
283   EmitCFIEndProcImpl(*CurFrame);
284 }
285 
286 void MCStreamer::EmitCFIEndProcImpl(MCDwarfFrameInfo &Frame) {
287   // Put a dummy non-null value in Frame.End to mark that this frame has been
288   // closed.
289   Frame.End = (MCSymbol *) 1;
290 }
291 
292 MCSymbol *MCStreamer::EmitCFICommon() {
293   EnsureValidDwarfFrame();
294   MCSymbol *Label = getContext().createTempSymbol();
295   EmitLabel(Label);
296   return Label;
297 }
298 
299 void MCStreamer::EmitCFIDefCfa(int64_t Register, int64_t Offset) {
300   MCSymbol *Label = EmitCFICommon();
301   MCCFIInstruction Instruction =
302     MCCFIInstruction::createDefCfa(Label, Register, Offset);
303   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
304   CurFrame->Instructions.push_back(Instruction);
305   CurFrame->CurrentCfaRegister = static_cast<unsigned>(Register);
306 }
307 
308 void MCStreamer::EmitCFIDefCfaOffset(int64_t Offset) {
309   MCSymbol *Label = EmitCFICommon();
310   MCCFIInstruction Instruction =
311     MCCFIInstruction::createDefCfaOffset(Label, Offset);
312   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
313   CurFrame->Instructions.push_back(Instruction);
314 }
315 
316 void MCStreamer::EmitCFIAdjustCfaOffset(int64_t Adjustment) {
317   MCSymbol *Label = EmitCFICommon();
318   MCCFIInstruction Instruction =
319     MCCFIInstruction::createAdjustCfaOffset(Label, Adjustment);
320   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
321   CurFrame->Instructions.push_back(Instruction);
322 }
323 
324 void MCStreamer::EmitCFIDefCfaRegister(int64_t Register) {
325   MCSymbol *Label = EmitCFICommon();
326   MCCFIInstruction Instruction =
327     MCCFIInstruction::createDefCfaRegister(Label, Register);
328   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
329   CurFrame->Instructions.push_back(Instruction);
330   CurFrame->CurrentCfaRegister = static_cast<unsigned>(Register);
331 }
332 
333 void MCStreamer::EmitCFIOffset(int64_t Register, int64_t Offset) {
334   MCSymbol *Label = EmitCFICommon();
335   MCCFIInstruction Instruction =
336     MCCFIInstruction::createOffset(Label, Register, Offset);
337   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
338   CurFrame->Instructions.push_back(Instruction);
339 }
340 
341 void MCStreamer::EmitCFIRelOffset(int64_t Register, int64_t Offset) {
342   MCSymbol *Label = EmitCFICommon();
343   MCCFIInstruction Instruction =
344     MCCFIInstruction::createRelOffset(Label, Register, Offset);
345   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
346   CurFrame->Instructions.push_back(Instruction);
347 }
348 
349 void MCStreamer::EmitCFIPersonality(const MCSymbol *Sym,
350                                     unsigned Encoding) {
351   EnsureValidDwarfFrame();
352   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
353   CurFrame->Personality = Sym;
354   CurFrame->PersonalityEncoding = Encoding;
355 }
356 
357 void MCStreamer::EmitCFILsda(const MCSymbol *Sym, unsigned Encoding) {
358   EnsureValidDwarfFrame();
359   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
360   CurFrame->Lsda = Sym;
361   CurFrame->LsdaEncoding = Encoding;
362 }
363 
364 void MCStreamer::EmitCFIRememberState() {
365   MCSymbol *Label = EmitCFICommon();
366   MCCFIInstruction Instruction = MCCFIInstruction::createRememberState(Label);
367   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
368   CurFrame->Instructions.push_back(Instruction);
369 }
370 
371 void MCStreamer::EmitCFIRestoreState() {
372   // FIXME: Error if there is no matching cfi_remember_state.
373   MCSymbol *Label = EmitCFICommon();
374   MCCFIInstruction Instruction = MCCFIInstruction::createRestoreState(Label);
375   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
376   CurFrame->Instructions.push_back(Instruction);
377 }
378 
379 void MCStreamer::EmitCFISameValue(int64_t Register) {
380   MCSymbol *Label = EmitCFICommon();
381   MCCFIInstruction Instruction =
382     MCCFIInstruction::createSameValue(Label, Register);
383   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
384   CurFrame->Instructions.push_back(Instruction);
385 }
386 
387 void MCStreamer::EmitCFIRestore(int64_t Register) {
388   MCSymbol *Label = EmitCFICommon();
389   MCCFIInstruction Instruction =
390     MCCFIInstruction::createRestore(Label, Register);
391   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
392   CurFrame->Instructions.push_back(Instruction);
393 }
394 
395 void MCStreamer::EmitCFIEscape(StringRef Values) {
396   MCSymbol *Label = EmitCFICommon();
397   MCCFIInstruction Instruction = MCCFIInstruction::createEscape(Label, Values);
398   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
399   CurFrame->Instructions.push_back(Instruction);
400 }
401 
402 void MCStreamer::EmitCFIGnuArgsSize(int64_t Size) {
403   MCSymbol *Label = EmitCFICommon();
404   MCCFIInstruction Instruction =
405     MCCFIInstruction::createGnuArgsSize(Label, Size);
406   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
407   CurFrame->Instructions.push_back(Instruction);
408 }
409 
410 void MCStreamer::EmitCFISignalFrame() {
411   EnsureValidDwarfFrame();
412   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
413   CurFrame->IsSignalFrame = true;
414 }
415 
416 void MCStreamer::EmitCFIUndefined(int64_t Register) {
417   MCSymbol *Label = EmitCFICommon();
418   MCCFIInstruction Instruction =
419     MCCFIInstruction::createUndefined(Label, Register);
420   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
421   CurFrame->Instructions.push_back(Instruction);
422 }
423 
424 void MCStreamer::EmitCFIRegister(int64_t Register1, int64_t Register2) {
425   MCSymbol *Label = EmitCFICommon();
426   MCCFIInstruction Instruction =
427     MCCFIInstruction::createRegister(Label, Register1, Register2);
428   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
429   CurFrame->Instructions.push_back(Instruction);
430 }
431 
432 void MCStreamer::EmitCFIWindowSave() {
433   MCSymbol *Label = EmitCFICommon();
434   MCCFIInstruction Instruction =
435     MCCFIInstruction::createWindowSave(Label);
436   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
437   CurFrame->Instructions.push_back(Instruction);
438 }
439 
440 void MCStreamer::EnsureValidWinFrameInfo() {
441   const MCAsmInfo *MAI = Context.getAsmInfo();
442   if (!MAI->usesWindowsCFI())
443     report_fatal_error(".seh_* directives are not supported on this target");
444   if (!CurrentWinFrameInfo || CurrentWinFrameInfo->End)
445     report_fatal_error("No open Win64 EH frame function!");
446 }
447 
448 void MCStreamer::EmitWinCFIStartProc(const MCSymbol *Symbol) {
449   const MCAsmInfo *MAI = Context.getAsmInfo();
450   if (!MAI->usesWindowsCFI())
451     report_fatal_error(".seh_* directives are not supported on this target");
452   if (CurrentWinFrameInfo && !CurrentWinFrameInfo->End)
453     report_fatal_error("Starting a function before ending the previous one!");
454 
455   MCSymbol *StartProc = getContext().createTempSymbol();
456   EmitLabel(StartProc);
457 
458   WinFrameInfos.push_back(new WinEH::FrameInfo(Symbol, StartProc));
459   CurrentWinFrameInfo = WinFrameInfos.back();
460   CurrentWinFrameInfo->TextSection = getCurrentSectionOnly();
461 }
462 
463 void MCStreamer::EmitWinCFIEndProc() {
464   EnsureValidWinFrameInfo();
465   if (CurrentWinFrameInfo->ChainedParent)
466     report_fatal_error("Not all chained regions terminated!");
467 
468   MCSymbol *Label = getContext().createTempSymbol();
469   EmitLabel(Label);
470   CurrentWinFrameInfo->End = Label;
471 }
472 
473 void MCStreamer::EmitWinCFIStartChained() {
474   EnsureValidWinFrameInfo();
475 
476   MCSymbol *StartProc = getContext().createTempSymbol();
477   EmitLabel(StartProc);
478 
479   WinFrameInfos.push_back(new WinEH::FrameInfo(CurrentWinFrameInfo->Function,
480                                                StartProc, CurrentWinFrameInfo));
481   CurrentWinFrameInfo = WinFrameInfos.back();
482   CurrentWinFrameInfo->TextSection = getCurrentSectionOnly();
483 }
484 
485 void MCStreamer::EmitWinCFIEndChained() {
486   EnsureValidWinFrameInfo();
487   if (!CurrentWinFrameInfo->ChainedParent)
488     report_fatal_error("End of a chained region outside a chained region!");
489 
490   MCSymbol *Label = getContext().createTempSymbol();
491   EmitLabel(Label);
492 
493   CurrentWinFrameInfo->End = Label;
494   CurrentWinFrameInfo =
495       const_cast<WinEH::FrameInfo *>(CurrentWinFrameInfo->ChainedParent);
496 }
497 
498 void MCStreamer::EmitWinEHHandler(const MCSymbol *Sym, bool Unwind,
499                                   bool Except) {
500   EnsureValidWinFrameInfo();
501   if (CurrentWinFrameInfo->ChainedParent)
502     report_fatal_error("Chained unwind areas can't have handlers!");
503   CurrentWinFrameInfo->ExceptionHandler = Sym;
504   if (!Except && !Unwind)
505     report_fatal_error("Don't know what kind of handler this is!");
506   if (Unwind)
507     CurrentWinFrameInfo->HandlesUnwind = true;
508   if (Except)
509     CurrentWinFrameInfo->HandlesExceptions = true;
510 }
511 
512 void MCStreamer::EmitWinEHHandlerData() {
513   EnsureValidWinFrameInfo();
514   if (CurrentWinFrameInfo->ChainedParent)
515     report_fatal_error("Chained unwind areas can't have handlers!");
516 }
517 
518 static MCSection *getWinCFISection(MCContext &Context, unsigned *NextWinCFIID,
519                                    MCSection *MainCFISec,
520                                    const MCSection *TextSec) {
521   // If this is the main .text section, use the main unwind info section.
522   if (TextSec == Context.getObjectFileInfo()->getTextSection())
523     return MainCFISec;
524 
525   const auto *TextSecCOFF = cast<MCSectionCOFF>(TextSec);
526   unsigned UniqueID = TextSecCOFF->getOrAssignWinCFISectionID(NextWinCFIID);
527 
528   // If this section is COMDAT, this unwind section should be COMDAT associative
529   // with its group.
530   const MCSymbol *KeySym = nullptr;
531   if (TextSecCOFF->getCharacteristics() & COFF::IMAGE_SCN_LNK_COMDAT)
532     KeySym = TextSecCOFF->getCOMDATSymbol();
533 
534   return Context.getAssociativeCOFFSection(cast<MCSectionCOFF>(MainCFISec),
535                                            KeySym, UniqueID);
536 }
537 
538 MCSection *MCStreamer::getAssociatedPDataSection(const MCSection *TextSec) {
539   return getWinCFISection(getContext(), &NextWinCFIID,
540                           getContext().getObjectFileInfo()->getPDataSection(),
541                           TextSec);
542 }
543 
544 MCSection *MCStreamer::getAssociatedXDataSection(const MCSection *TextSec) {
545   return getWinCFISection(getContext(), &NextWinCFIID,
546                           getContext().getObjectFileInfo()->getXDataSection(),
547                           TextSec);
548 }
549 
550 void MCStreamer::EmitSyntaxDirective() {}
551 
552 void MCStreamer::EmitWinCFIPushReg(unsigned Register) {
553   EnsureValidWinFrameInfo();
554 
555   MCSymbol *Label = getContext().createTempSymbol();
556   EmitLabel(Label);
557 
558   WinEH::Instruction Inst = Win64EH::Instruction::PushNonVol(Label, Register);
559   CurrentWinFrameInfo->Instructions.push_back(Inst);
560 }
561 
562 void MCStreamer::EmitWinCFISetFrame(unsigned Register, unsigned Offset) {
563   EnsureValidWinFrameInfo();
564   if (CurrentWinFrameInfo->LastFrameInst >= 0)
565     report_fatal_error("Frame register and offset already specified!");
566   if (Offset & 0x0F)
567     report_fatal_error("Misaligned frame pointer offset!");
568   if (Offset > 240)
569     report_fatal_error("Frame offset must be less than or equal to 240!");
570 
571   MCSymbol *Label = getContext().createTempSymbol();
572   EmitLabel(Label);
573 
574   WinEH::Instruction Inst =
575       Win64EH::Instruction::SetFPReg(Label, Register, Offset);
576   CurrentWinFrameInfo->LastFrameInst = CurrentWinFrameInfo->Instructions.size();
577   CurrentWinFrameInfo->Instructions.push_back(Inst);
578 }
579 
580 void MCStreamer::EmitWinCFIAllocStack(unsigned Size) {
581   EnsureValidWinFrameInfo();
582   if (Size == 0)
583     report_fatal_error("Allocation size must be non-zero!");
584   if (Size & 7)
585     report_fatal_error("Misaligned stack allocation!");
586 
587   MCSymbol *Label = getContext().createTempSymbol();
588   EmitLabel(Label);
589 
590   WinEH::Instruction Inst = Win64EH::Instruction::Alloc(Label, Size);
591   CurrentWinFrameInfo->Instructions.push_back(Inst);
592 }
593 
594 void MCStreamer::EmitWinCFISaveReg(unsigned Register, unsigned Offset) {
595   EnsureValidWinFrameInfo();
596   if (Offset & 7)
597     report_fatal_error("Misaligned saved register offset!");
598 
599   MCSymbol *Label = getContext().createTempSymbol();
600   EmitLabel(Label);
601 
602   WinEH::Instruction Inst =
603       Win64EH::Instruction::SaveNonVol(Label, Register, Offset);
604   CurrentWinFrameInfo->Instructions.push_back(Inst);
605 }
606 
607 void MCStreamer::EmitWinCFISaveXMM(unsigned Register, unsigned Offset) {
608   EnsureValidWinFrameInfo();
609   if (Offset & 0x0F)
610     report_fatal_error("Misaligned saved vector register offset!");
611 
612   MCSymbol *Label = getContext().createTempSymbol();
613   EmitLabel(Label);
614 
615   WinEH::Instruction Inst =
616       Win64EH::Instruction::SaveXMM(Label, Register, Offset);
617   CurrentWinFrameInfo->Instructions.push_back(Inst);
618 }
619 
620 void MCStreamer::EmitWinCFIPushFrame(bool Code) {
621   EnsureValidWinFrameInfo();
622   if (CurrentWinFrameInfo->Instructions.size() > 0)
623     report_fatal_error("If present, PushMachFrame must be the first UOP");
624 
625   MCSymbol *Label = getContext().createTempSymbol();
626   EmitLabel(Label);
627 
628   WinEH::Instruction Inst = Win64EH::Instruction::PushMachFrame(Label, Code);
629   CurrentWinFrameInfo->Instructions.push_back(Inst);
630 }
631 
632 void MCStreamer::EmitWinCFIEndProlog() {
633   EnsureValidWinFrameInfo();
634 
635   MCSymbol *Label = getContext().createTempSymbol();
636   EmitLabel(Label);
637 
638   CurrentWinFrameInfo->PrologEnd = Label;
639 }
640 
641 void MCStreamer::EmitCOFFSafeSEH(MCSymbol const *Symbol) {
642 }
643 
644 void MCStreamer::EmitCOFFSectionIndex(MCSymbol const *Symbol) {
645 }
646 
647 void MCStreamer::EmitCOFFSecRel32(MCSymbol const *Symbol) {
648 }
649 
650 /// EmitRawText - If this file is backed by an assembly streamer, this dumps
651 /// the specified string in the output .s file.  This capability is
652 /// indicated by the hasRawTextSupport() predicate.
653 void MCStreamer::EmitRawTextImpl(StringRef String) {
654   errs() << "EmitRawText called on an MCStreamer that doesn't support it, "
655   " something must not be fully mc'ized\n";
656   abort();
657 }
658 
659 void MCStreamer::EmitRawText(const Twine &T) {
660   SmallString<128> Str;
661   EmitRawTextImpl(T.toStringRef(Str));
662 }
663 
664 void MCStreamer::EmitWindowsUnwindTables() {
665 }
666 
667 void MCStreamer::Finish() {
668   if (!DwarfFrameInfos.empty() && !DwarfFrameInfos.back().End)
669     report_fatal_error("Unfinished frame!");
670 
671   MCTargetStreamer *TS = getTargetStreamer();
672   if (TS)
673     TS->finish();
674 
675   FinishImpl();
676 }
677 
678 void MCStreamer::EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) {
679   visitUsedExpr(*Value);
680   Symbol->setVariableValue(Value);
681 
682   MCTargetStreamer *TS = getTargetStreamer();
683   if (TS)
684     TS->emitAssignment(Symbol, Value);
685 }
686 
687 void MCTargetStreamer::prettyPrintAsm(MCInstPrinter &InstPrinter, raw_ostream &OS,
688                               const MCInst &Inst, const MCSubtargetInfo &STI) {
689   InstPrinter.printInst(&Inst, OS, "", STI);
690 }
691 
692 void MCStreamer::visitUsedSymbol(const MCSymbol &Sym) {
693 }
694 
695 void MCStreamer::visitUsedExpr(const MCExpr &Expr) {
696   switch (Expr.getKind()) {
697   case MCExpr::Target:
698     cast<MCTargetExpr>(Expr).visitUsedExpr(*this);
699     break;
700 
701   case MCExpr::Constant:
702     break;
703 
704   case MCExpr::Binary: {
705     const MCBinaryExpr &BE = cast<MCBinaryExpr>(Expr);
706     visitUsedExpr(*BE.getLHS());
707     visitUsedExpr(*BE.getRHS());
708     break;
709   }
710 
711   case MCExpr::SymbolRef:
712     visitUsedSymbol(cast<MCSymbolRefExpr>(Expr).getSymbol());
713     break;
714 
715   case MCExpr::Unary:
716     visitUsedExpr(*cast<MCUnaryExpr>(Expr).getSubExpr());
717     break;
718   }
719 }
720 
721 void MCStreamer::EmitInstruction(const MCInst &Inst,
722                                  const MCSubtargetInfo &STI) {
723   // Scan for values.
724   for (unsigned i = Inst.getNumOperands(); i--;)
725     if (Inst.getOperand(i).isExpr())
726       visitUsedExpr(*Inst.getOperand(i).getExpr());
727 }
728 
729 void MCStreamer::emitAbsoluteSymbolDiff(const MCSymbol *Hi, const MCSymbol *Lo,
730                                         unsigned Size) {
731   // Get the Hi-Lo expression.
732   const MCExpr *Diff =
733       MCBinaryExpr::createSub(MCSymbolRefExpr::create(Hi, Context),
734                               MCSymbolRefExpr::create(Lo, Context), Context);
735 
736   const MCAsmInfo *MAI = Context.getAsmInfo();
737   if (!MAI->doesSetDirectiveSuppressReloc()) {
738     EmitValue(Diff, Size);
739     return;
740   }
741 
742   // Otherwise, emit with .set (aka assignment).
743   MCSymbol *SetLabel = Context.createTempSymbol("set", true);
744   EmitAssignment(SetLabel, Diff);
745   EmitSymbolValue(SetLabel, Size);
746 }
747 
748 void MCStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) {}
749 void MCStreamer::EmitThumbFunc(MCSymbol *Func) {}
750 void MCStreamer::EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {}
751 void MCStreamer::BeginCOFFSymbolDef(const MCSymbol *Symbol) {}
752 void MCStreamer::EndCOFFSymbolDef() {}
753 void MCStreamer::EmitFileDirective(StringRef Filename) {}
754 void MCStreamer::EmitCOFFSymbolStorageClass(int StorageClass) {}
755 void MCStreamer::EmitCOFFSymbolType(int Type) {}
756 void MCStreamer::emitELFSize(MCSymbolELF *Symbol, const MCExpr *Value) {}
757 void MCStreamer::EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
758                                        unsigned ByteAlignment) {}
759 void MCStreamer::EmitTBSSSymbol(MCSection *Section, MCSymbol *Symbol,
760                                 uint64_t Size, unsigned ByteAlignment) {}
761 void MCStreamer::ChangeSection(MCSection *, const MCExpr *) {}
762 void MCStreamer::EmitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol) {}
763 void MCStreamer::EmitBytes(StringRef Data) {}
764 void MCStreamer::EmitBinaryData(StringRef Data) { EmitBytes(Data); }
765 void MCStreamer::EmitValueImpl(const MCExpr *Value, unsigned Size, SMLoc Loc) {
766   visitUsedExpr(*Value);
767 }
768 void MCStreamer::EmitULEB128Value(const MCExpr *Value) {}
769 void MCStreamer::EmitSLEB128Value(const MCExpr *Value) {}
770 void MCStreamer::emitFill(const MCExpr &NumBytes, uint64_t Value, SMLoc Loc) {}
771 void MCStreamer::emitFill(const MCExpr &NumValues, int64_t Size, int64_t Expr,
772                           SMLoc Loc) {}
773 void MCStreamer::EmitValueToAlignment(unsigned ByteAlignment, int64_t Value,
774                                       unsigned ValueSize,
775                                       unsigned MaxBytesToEmit) {}
776 void MCStreamer::EmitCodeAlignment(unsigned ByteAlignment,
777                                    unsigned MaxBytesToEmit) {}
778 void MCStreamer::emitValueToOffset(const MCExpr *Offset, unsigned char Value) {}
779 void MCStreamer::EmitBundleAlignMode(unsigned AlignPow2) {}
780 void MCStreamer::EmitBundleLock(bool AlignToEnd) {}
781 void MCStreamer::FinishImpl() {}
782 void MCStreamer::EmitBundleUnlock() {}
783 
784 void MCStreamer::SwitchSection(MCSection *Section, const MCExpr *Subsection) {
785   assert(Section && "Cannot switch to a null section!");
786   MCSectionSubPair curSection = SectionStack.back().first;
787   SectionStack.back().second = curSection;
788   if (MCSectionSubPair(Section, Subsection) != curSection) {
789     ChangeSection(Section, Subsection);
790     SectionStack.back().first = MCSectionSubPair(Section, Subsection);
791     assert(!Section->hasEnded() && "Section already ended");
792     MCSymbol *Sym = Section->getBeginSymbol();
793     if (Sym && !Sym->isInSection())
794       EmitLabel(Sym);
795   }
796 }
797 
798 MCSymbol *MCStreamer::endSection(MCSection *Section) {
799   // TODO: keep track of the last subsection so that this symbol appears in the
800   // correct place.
801   MCSymbol *Sym = Section->getEndSymbol(Context);
802   if (Sym->isInSection())
803     return Sym;
804 
805   SwitchSection(Section);
806   EmitLabel(Sym);
807   return Sym;
808 }
809