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/MCObjectFileInfo.h"
18 #include "llvm/MC/MCObjectWriter.h"
19 #include "llvm/MC/MCSymbol.h"
20 #include "llvm/MC/MCWin64EH.h"
21 #include "llvm/Support/ErrorHandling.h"
22 #include "llvm/Support/LEB128.h"
23 #include "llvm/Support/raw_ostream.h"
24 #include <cstdlib>
25 using namespace llvm;
26 
27 // Pin the vtables to this file.
28 MCTargetStreamer::~MCTargetStreamer() {}
29 
30 MCTargetStreamer::MCTargetStreamer(MCStreamer &S) : Streamer(S) {
31   S.setTargetStreamer(this);
32 }
33 
34 void MCTargetStreamer::emitLabel(MCSymbol *Symbol) {}
35 
36 void MCTargetStreamer::finish() {}
37 
38 void MCTargetStreamer::emitAssignment(MCSymbol *Symbol, const MCExpr *Value) {}
39 
40 MCStreamer::MCStreamer(MCContext &Ctx)
41     : Context(Ctx), CurrentWinFrameInfo(nullptr) {
42   SectionStack.push_back(std::pair<MCSectionSubPair, MCSectionSubPair>());
43 }
44 
45 MCStreamer::~MCStreamer() {
46   for (unsigned i = 0; i < getNumWinFrameInfos(); ++i)
47     delete WinFrameInfos[i];
48 }
49 
50 void MCStreamer::reset() {
51   for (unsigned i = 0; i < getNumWinFrameInfos(); ++i)
52     delete WinFrameInfos[i];
53   WinFrameInfos.clear();
54   CurrentWinFrameInfo = nullptr;
55   SectionStack.clear();
56   SectionStack.push_back(std::pair<MCSectionSubPair, MCSectionSubPair>());
57 }
58 
59 const MCExpr *MCStreamer::BuildSymbolDiff(MCContext &Context,
60                                           const MCSymbol *A,
61                                           const MCSymbol *B) {
62   MCSymbolRefExpr::VariantKind Variant = MCSymbolRefExpr::VK_None;
63   const MCExpr *ARef =
64     MCSymbolRefExpr::Create(A, Variant, Context);
65   const MCExpr *BRef =
66     MCSymbolRefExpr::Create(B, Variant, Context);
67   const MCExpr *AddrDelta =
68     MCBinaryExpr::Create(MCBinaryExpr::Sub, ARef, BRef, Context);
69   return AddrDelta;
70 }
71 
72 const MCExpr *MCStreamer::ForceExpAbs(const MCExpr* Expr) {
73   assert(!isa<MCSymbolRefExpr>(Expr));
74   if (Context.getAsmInfo()->hasAggressiveSymbolFolding())
75     return Expr;
76 
77   MCSymbol *ABS = Context.CreateTempSymbol();
78   EmitAssignment(ABS, Expr);
79   return MCSymbolRefExpr::Create(ABS, Context);
80 }
81 
82 raw_ostream &MCStreamer::GetCommentOS() {
83   // By default, discard comments.
84   return nulls();
85 }
86 
87 void MCStreamer::emitRawComment(const Twine &T, bool TabPrefix) {}
88 
89 void MCStreamer::generateCompactUnwindEncodings(MCAsmBackend *MAB) {
90   for (auto &FI : DwarfFrameInfos)
91     FI.CompactUnwindEncoding =
92         (MAB ? MAB->generateCompactUnwindEncoding(FI.Instructions) : 0);
93 }
94 
95 void MCStreamer::EmitDwarfSetLineAddr(int64_t LineDelta,
96                                       const MCSymbol *Label, int PointerSize) {
97   // emit the sequence to set the address
98   EmitIntValue(dwarf::DW_LNS_extended_op, 1);
99   EmitULEB128IntValue(PointerSize + 1);
100   EmitIntValue(dwarf::DW_LNE_set_address, 1);
101   EmitSymbolValue(Label, PointerSize);
102 
103   // emit the sequence for the LineDelta (from 1) and a zero address delta.
104   MCDwarfLineAddr::Emit(this, LineDelta, 0);
105 }
106 
107 /// EmitIntValue - Special case of EmitValue that avoids the client having to
108 /// pass in a MCExpr for constant integers.
109 void MCStreamer::EmitIntValue(uint64_t Value, unsigned Size) {
110   assert(Size <= 8 && "Invalid size");
111   assert((isUIntN(8 * Size, Value) || isIntN(8 * Size, Value)) &&
112          "Invalid size");
113   char buf[8];
114   const bool isLittleEndian = Context.getAsmInfo()->isLittleEndian();
115   for (unsigned i = 0; i != Size; ++i) {
116     unsigned index = isLittleEndian ? i : (Size - i - 1);
117     buf[i] = uint8_t(Value >> (index * 8));
118   }
119   EmitBytes(StringRef(buf, Size));
120 }
121 
122 /// EmitULEB128Value - Special case of EmitULEB128Value that avoids the
123 /// client having to pass in a MCExpr for constant integers.
124 void MCStreamer::EmitULEB128IntValue(uint64_t Value, unsigned Padding) {
125   SmallString<128> Tmp;
126   raw_svector_ostream OSE(Tmp);
127   encodeULEB128(Value, OSE, Padding);
128   EmitBytes(OSE.str());
129 }
130 
131 /// EmitSLEB128Value - Special case of EmitSLEB128Value that avoids the
132 /// client having to pass in a MCExpr for constant integers.
133 void MCStreamer::EmitSLEB128IntValue(int64_t Value) {
134   SmallString<128> Tmp;
135   raw_svector_ostream OSE(Tmp);
136   encodeSLEB128(Value, OSE);
137   EmitBytes(OSE.str());
138 }
139 
140 void MCStreamer::EmitAbsValue(const MCExpr *Value, unsigned Size) {
141   const MCExpr *ABS = ForceExpAbs(Value);
142   EmitValue(ABS, Size);
143 }
144 
145 
146 void MCStreamer::EmitValue(const MCExpr *Value, unsigned Size,
147                            const SMLoc &Loc) {
148   EmitValueImpl(Value, Size, Loc);
149 }
150 
151 void MCStreamer::EmitSymbolValue(const MCSymbol *Sym, unsigned Size,
152                                  bool IsSectionRelative) {
153   assert((!IsSectionRelative || Size == 4) &&
154          "SectionRelative value requires 4-bytes");
155 
156   if (!IsSectionRelative)
157     EmitValueImpl(MCSymbolRefExpr::Create(Sym, getContext()), Size);
158   else
159     EmitCOFFSecRel32(Sym);
160 }
161 
162 void MCStreamer::EmitGPRel64Value(const MCExpr *Value) {
163   report_fatal_error("unsupported directive in streamer");
164 }
165 
166 void MCStreamer::EmitGPRel32Value(const MCExpr *Value) {
167   report_fatal_error("unsupported directive in streamer");
168 }
169 
170 /// EmitFill - Emit NumBytes bytes worth of the value specified by
171 /// FillValue.  This implements directives such as '.space'.
172 void MCStreamer::EmitFill(uint64_t NumBytes, uint8_t FillValue) {
173   const MCExpr *E = MCConstantExpr::Create(FillValue, getContext());
174   for (uint64_t i = 0, e = NumBytes; i != e; ++i)
175     EmitValue(E, 1);
176 }
177 
178 /// The implementation in this class just redirects to EmitFill.
179 void MCStreamer::EmitZeros(uint64_t NumBytes) {
180   EmitFill(NumBytes, 0);
181 }
182 
183 unsigned MCStreamer::EmitDwarfFileDirective(unsigned FileNo,
184                                             StringRef Directory,
185                                             StringRef Filename, unsigned CUID) {
186   return getContext().GetDwarfFile(Directory, Filename, FileNo, CUID);
187 }
188 
189 void MCStreamer::EmitDwarfLocDirective(unsigned FileNo, unsigned Line,
190                                        unsigned Column, unsigned Flags,
191                                        unsigned Isa,
192                                        unsigned Discriminator,
193                                        StringRef FileName) {
194   getContext().setCurrentDwarfLoc(FileNo, Line, Column, Flags, Isa,
195                                   Discriminator);
196 }
197 
198 MCSymbol *MCStreamer::getDwarfLineTableSymbol(unsigned CUID) {
199   MCDwarfLineTable &Table = getContext().getMCDwarfLineTable(CUID);
200   if (!Table.getLabel()) {
201     StringRef Prefix = Context.getAsmInfo()->getPrivateGlobalPrefix();
202     Table.setLabel(
203         Context.GetOrCreateSymbol(Prefix + "line_table_start" + Twine(CUID)));
204   }
205   return Table.getLabel();
206 }
207 
208 MCDwarfFrameInfo *MCStreamer::getCurrentDwarfFrameInfo() {
209   if (DwarfFrameInfos.empty())
210     return nullptr;
211   return &DwarfFrameInfos.back();
212 }
213 
214 void MCStreamer::EnsureValidDwarfFrame() {
215   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
216   if (!CurFrame || CurFrame->End)
217     report_fatal_error("No open frame");
218 }
219 
220 void MCStreamer::EmitEHSymAttributes(const MCSymbol *Symbol,
221                                      MCSymbol *EHSymbol) {
222 }
223 
224 void MCStreamer::InitSections() {
225   SwitchSection(getContext().getObjectFileInfo()->getTextSection());
226 }
227 
228 void MCStreamer::AssignSection(MCSymbol *Symbol, const MCSection *Section) {
229   if (Section)
230     Symbol->setSection(*Section);
231   else
232     Symbol->setUndefined();
233 
234   // As we emit symbols into a section, track the order so that they can
235   // be sorted upon later. Zero is reserved to mean 'unemitted'.
236   SymbolOrdering[Symbol] = 1 + SymbolOrdering.size();
237 }
238 
239 void MCStreamer::EmitLabel(MCSymbol *Symbol) {
240   assert(!Symbol->isVariable() && "Cannot emit a variable symbol!");
241   assert(getCurrentSection().first && "Cannot emit before setting section!");
242   AssignSection(Symbol, getCurrentSection().first);
243 
244   MCTargetStreamer *TS = getTargetStreamer();
245   if (TS)
246     TS->emitLabel(Symbol);
247 }
248 
249 void MCStreamer::EmitCompactUnwindEncoding(uint32_t CompactUnwindEncoding) {
250   EnsureValidDwarfFrame();
251   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
252   CurFrame->CompactUnwindEncoding = CompactUnwindEncoding;
253 }
254 
255 void MCStreamer::EmitCFISections(bool EH, bool Debug) {
256   assert(EH || Debug);
257 }
258 
259 void MCStreamer::EmitCFIStartProc(bool IsSimple) {
260   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
261   if (CurFrame && !CurFrame->End)
262     report_fatal_error("Starting a frame before finishing the previous one!");
263 
264   MCDwarfFrameInfo Frame;
265   Frame.IsSimple = IsSimple;
266   EmitCFIStartProcImpl(Frame);
267 
268   DwarfFrameInfos.push_back(Frame);
269 }
270 
271 void MCStreamer::EmitCFIStartProcImpl(MCDwarfFrameInfo &Frame) {
272 }
273 
274 void MCStreamer::EmitCFIEndProc() {
275   EnsureValidDwarfFrame();
276   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
277   EmitCFIEndProcImpl(*CurFrame);
278 }
279 
280 void MCStreamer::EmitCFIEndProcImpl(MCDwarfFrameInfo &Frame) {
281   // Put a dummy non-null value in Frame.End to mark that this frame has been
282   // closed.
283   Frame.End = (MCSymbol *) 1;
284 }
285 
286 MCSymbol *MCStreamer::EmitCFICommon() {
287   EnsureValidDwarfFrame();
288   MCSymbol *Label = getContext().CreateTempSymbol();
289   EmitLabel(Label);
290   return Label;
291 }
292 
293 void MCStreamer::EmitCFIDefCfa(int64_t Register, int64_t Offset) {
294   MCSymbol *Label = EmitCFICommon();
295   MCCFIInstruction Instruction =
296     MCCFIInstruction::createDefCfa(Label, Register, Offset);
297   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
298   CurFrame->Instructions.push_back(Instruction);
299 }
300 
301 void MCStreamer::EmitCFIDefCfaOffset(int64_t Offset) {
302   MCSymbol *Label = EmitCFICommon();
303   MCCFIInstruction Instruction =
304     MCCFIInstruction::createDefCfaOffset(Label, Offset);
305   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
306   CurFrame->Instructions.push_back(Instruction);
307 }
308 
309 void MCStreamer::EmitCFIAdjustCfaOffset(int64_t Adjustment) {
310   MCSymbol *Label = EmitCFICommon();
311   MCCFIInstruction Instruction =
312     MCCFIInstruction::createAdjustCfaOffset(Label, Adjustment);
313   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
314   CurFrame->Instructions.push_back(Instruction);
315 }
316 
317 void MCStreamer::EmitCFIDefCfaRegister(int64_t Register) {
318   MCSymbol *Label = EmitCFICommon();
319   MCCFIInstruction Instruction =
320     MCCFIInstruction::createDefCfaRegister(Label, Register);
321   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
322   CurFrame->Instructions.push_back(Instruction);
323 }
324 
325 void MCStreamer::EmitCFIOffset(int64_t Register, int64_t Offset) {
326   MCSymbol *Label = EmitCFICommon();
327   MCCFIInstruction Instruction =
328     MCCFIInstruction::createOffset(Label, Register, Offset);
329   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
330   CurFrame->Instructions.push_back(Instruction);
331 }
332 
333 void MCStreamer::EmitCFIRelOffset(int64_t Register, int64_t Offset) {
334   MCSymbol *Label = EmitCFICommon();
335   MCCFIInstruction Instruction =
336     MCCFIInstruction::createRelOffset(Label, Register, Offset);
337   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
338   CurFrame->Instructions.push_back(Instruction);
339 }
340 
341 void MCStreamer::EmitCFIPersonality(const MCSymbol *Sym,
342                                     unsigned Encoding) {
343   EnsureValidDwarfFrame();
344   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
345   CurFrame->Personality = Sym;
346   CurFrame->PersonalityEncoding = Encoding;
347 }
348 
349 void MCStreamer::EmitCFILsda(const MCSymbol *Sym, unsigned Encoding) {
350   EnsureValidDwarfFrame();
351   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
352   CurFrame->Lsda = Sym;
353   CurFrame->LsdaEncoding = Encoding;
354 }
355 
356 void MCStreamer::EmitCFIRememberState() {
357   MCSymbol *Label = EmitCFICommon();
358   MCCFIInstruction Instruction = MCCFIInstruction::createRememberState(Label);
359   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
360   CurFrame->Instructions.push_back(Instruction);
361 }
362 
363 void MCStreamer::EmitCFIRestoreState() {
364   // FIXME: Error if there is no matching cfi_remember_state.
365   MCSymbol *Label = EmitCFICommon();
366   MCCFIInstruction Instruction = MCCFIInstruction::createRestoreState(Label);
367   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
368   CurFrame->Instructions.push_back(Instruction);
369 }
370 
371 void MCStreamer::EmitCFISameValue(int64_t Register) {
372   MCSymbol *Label = EmitCFICommon();
373   MCCFIInstruction Instruction =
374     MCCFIInstruction::createSameValue(Label, Register);
375   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
376   CurFrame->Instructions.push_back(Instruction);
377 }
378 
379 void MCStreamer::EmitCFIRestore(int64_t Register) {
380   MCSymbol *Label = EmitCFICommon();
381   MCCFIInstruction Instruction =
382     MCCFIInstruction::createRestore(Label, Register);
383   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
384   CurFrame->Instructions.push_back(Instruction);
385 }
386 
387 void MCStreamer::EmitCFIEscape(StringRef Values) {
388   MCSymbol *Label = EmitCFICommon();
389   MCCFIInstruction Instruction = MCCFIInstruction::createEscape(Label, Values);
390   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
391   CurFrame->Instructions.push_back(Instruction);
392 }
393 
394 void MCStreamer::EmitCFISignalFrame() {
395   EnsureValidDwarfFrame();
396   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
397   CurFrame->IsSignalFrame = true;
398 }
399 
400 void MCStreamer::EmitCFIUndefined(int64_t Register) {
401   MCSymbol *Label = EmitCFICommon();
402   MCCFIInstruction Instruction =
403     MCCFIInstruction::createUndefined(Label, Register);
404   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
405   CurFrame->Instructions.push_back(Instruction);
406 }
407 
408 void MCStreamer::EmitCFIRegister(int64_t Register1, int64_t Register2) {
409   MCSymbol *Label = EmitCFICommon();
410   MCCFIInstruction Instruction =
411     MCCFIInstruction::createRegister(Label, Register1, Register2);
412   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
413   CurFrame->Instructions.push_back(Instruction);
414 }
415 
416 void MCStreamer::EmitCFIWindowSave() {
417   MCSymbol *Label = EmitCFICommon();
418   MCCFIInstruction Instruction =
419     MCCFIInstruction::createWindowSave(Label);
420   MCDwarfFrameInfo *CurFrame = getCurrentDwarfFrameInfo();
421   CurFrame->Instructions.push_back(Instruction);
422 }
423 
424 void MCStreamer::EnsureValidWinFrameInfo() {
425   if (!CurrentWinFrameInfo || CurrentWinFrameInfo->End)
426     report_fatal_error("No open Win64 EH frame function!");
427 }
428 
429 void MCStreamer::EmitWinCFIStartProc(const MCSymbol *Symbol) {
430   if (CurrentWinFrameInfo && !CurrentWinFrameInfo->End)
431     report_fatal_error("Starting a function before ending the previous one!");
432   MCWinFrameInfo *Frame = new MCWinFrameInfo;
433   Frame->Begin = getContext().CreateTempSymbol();
434   Frame->Function = Symbol;
435   EmitLabel(Frame->Begin);
436   WinFrameInfos.push_back(Frame);
437   CurrentWinFrameInfo = WinFrameInfos.back();
438 }
439 
440 void MCStreamer::EmitWinCFIEndProc() {
441   EnsureValidWinFrameInfo();
442   if (CurrentWinFrameInfo->ChainedParent)
443     report_fatal_error("Not all chained regions terminated!");
444   CurrentWinFrameInfo->End = getContext().CreateTempSymbol();
445   EmitLabel(CurrentWinFrameInfo->End);
446 }
447 
448 void MCStreamer::EmitWinCFIStartChained() {
449   EnsureValidWinFrameInfo();
450   MCWinFrameInfo *Frame = new MCWinFrameInfo;
451   Frame->Begin = getContext().CreateTempSymbol();
452   Frame->Function = CurrentWinFrameInfo->Function;
453   Frame->ChainedParent = CurrentWinFrameInfo;
454   EmitLabel(Frame->Begin);
455   WinFrameInfos.push_back(Frame);
456   CurrentWinFrameInfo = WinFrameInfos.back();
457 }
458 
459 void MCStreamer::EmitWinCFIEndChained() {
460   EnsureValidWinFrameInfo();
461   if (!CurrentWinFrameInfo->ChainedParent)
462     report_fatal_error("End of a chained region outside a chained region!");
463   CurrentWinFrameInfo->End = getContext().CreateTempSymbol();
464   EmitLabel(CurrentWinFrameInfo->End);
465   CurrentWinFrameInfo = CurrentWinFrameInfo->ChainedParent;
466 }
467 
468 void MCStreamer::EmitWinEHHandler(const MCSymbol *Sym, bool Unwind,
469                                   bool Except) {
470   EnsureValidWinFrameInfo();
471   if (CurrentWinFrameInfo->ChainedParent)
472     report_fatal_error("Chained unwind areas can't have handlers!");
473   CurrentWinFrameInfo->ExceptionHandler = Sym;
474   if (!Except && !Unwind)
475     report_fatal_error("Don't know what kind of handler this is!");
476   if (Unwind)
477     CurrentWinFrameInfo->HandlesUnwind = true;
478   if (Except)
479     CurrentWinFrameInfo->HandlesExceptions = true;
480 }
481 
482 void MCStreamer::EmitWinEHHandlerData() {
483   EnsureValidWinFrameInfo();
484   if (CurrentWinFrameInfo->ChainedParent)
485     report_fatal_error("Chained unwind areas can't have handlers!");
486 }
487 
488 void MCStreamer::EmitWinCFIPushReg(unsigned Register) {
489   EnsureValidWinFrameInfo();
490 
491   MCSymbol *Label = getContext().CreateTempSymbol();
492   EmitLabel(Label);
493 
494   WinEH::Instruction Inst = Win64EH::Instruction::PushNonVol(Label, Register);
495   CurrentWinFrameInfo->Instructions.push_back(Inst);
496 }
497 
498 void MCStreamer::EmitWinCFISetFrame(unsigned Register, unsigned Offset) {
499   EnsureValidWinFrameInfo();
500   if (CurrentWinFrameInfo->LastFrameInst >= 0)
501     report_fatal_error("Frame register and offset already specified!");
502   if (Offset & 0x0F)
503     report_fatal_error("Misaligned frame pointer offset!");
504   if (Offset > 240)
505     report_fatal_error("Frame offset must be less than or equal to 240!");
506 
507   MCSymbol *Label = getContext().CreateTempSymbol();
508   EmitLabel(Label);
509 
510   WinEH::Instruction Inst =
511       Win64EH::Instruction::SetFPReg(Label, Register, Offset);
512   CurrentWinFrameInfo->LastFrameInst = CurrentWinFrameInfo->Instructions.size();
513   CurrentWinFrameInfo->Instructions.push_back(Inst);
514 }
515 
516 void MCStreamer::EmitWinCFIAllocStack(unsigned Size) {
517   EnsureValidWinFrameInfo();
518   if (Size == 0)
519     report_fatal_error("Allocation size must be non-zero!");
520   if (Size & 7)
521     report_fatal_error("Misaligned stack allocation!");
522 
523   MCSymbol *Label = getContext().CreateTempSymbol();
524   EmitLabel(Label);
525 
526   WinEH::Instruction Inst = Win64EH::Instruction::Alloc(Label, Size);
527   CurrentWinFrameInfo->Instructions.push_back(Inst);
528 }
529 
530 void MCStreamer::EmitWinCFISaveReg(unsigned Register, unsigned Offset) {
531   EnsureValidWinFrameInfo();
532   if (Offset & 7)
533     report_fatal_error("Misaligned saved register offset!");
534 
535   MCSymbol *Label = getContext().CreateTempSymbol();
536   EmitLabel(Label);
537 
538   WinEH::Instruction Inst =
539       Win64EH::Instruction::SaveNonVol(Label, Register, Offset);
540   CurrentWinFrameInfo->Instructions.push_back(Inst);
541 }
542 
543 void MCStreamer::EmitWinCFISaveXMM(unsigned Register, unsigned Offset) {
544   EnsureValidWinFrameInfo();
545   if (Offset & 0x0F)
546     report_fatal_error("Misaligned saved vector register offset!");
547 
548   MCSymbol *Label = getContext().CreateTempSymbol();
549   EmitLabel(Label);
550 
551   WinEH::Instruction Inst =
552       Win64EH::Instruction::SaveXMM(Label, Register, Offset);
553   CurrentWinFrameInfo->Instructions.push_back(Inst);
554 }
555 
556 void MCStreamer::EmitWinCFIPushFrame(bool Code) {
557   EnsureValidWinFrameInfo();
558   if (CurrentWinFrameInfo->Instructions.size() > 0)
559     report_fatal_error("If present, PushMachFrame must be the first UOP");
560 
561   MCSymbol *Label = getContext().CreateTempSymbol();
562   EmitLabel(Label);
563 
564   WinEH::Instruction Inst = Win64EH::Instruction::PushMachFrame(Label, Code);
565   CurrentWinFrameInfo->Instructions.push_back(Inst);
566 }
567 
568 void MCStreamer::EmitWinCFIEndProlog() {
569   EnsureValidWinFrameInfo();
570   CurrentWinFrameInfo->PrologEnd = getContext().CreateTempSymbol();
571   EmitLabel(CurrentWinFrameInfo->PrologEnd);
572 }
573 
574 void MCStreamer::EmitCOFFSectionIndex(MCSymbol const *Symbol) {
575 }
576 
577 void MCStreamer::EmitCOFFSecRel32(MCSymbol const *Symbol) {
578 }
579 
580 /// EmitRawText - If this file is backed by an assembly streamer, this dumps
581 /// the specified string in the output .s file.  This capability is
582 /// indicated by the hasRawTextSupport() predicate.
583 void MCStreamer::EmitRawTextImpl(StringRef String) {
584   errs() << "EmitRawText called on an MCStreamer that doesn't support it, "
585   " something must not be fully mc'ized\n";
586   abort();
587 }
588 
589 void MCStreamer::EmitRawText(const Twine &T) {
590   SmallString<128> Str;
591   EmitRawTextImpl(T.toStringRef(Str));
592 }
593 
594 void MCStreamer::EmitWindowsUnwindTables() {
595   if (!getNumWinFrameInfos())
596     return;
597 
598   MCWin64EHUnwindEmitter::Emit(*this);
599 }
600 
601 void MCStreamer::Finish() {
602   if (!DwarfFrameInfos.empty() && !DwarfFrameInfos.back().End)
603     report_fatal_error("Unfinished frame!");
604 
605   MCTargetStreamer *TS = getTargetStreamer();
606   if (TS)
607     TS->finish();
608 
609   FinishImpl();
610 }
611 
612 void MCStreamer::EmitAssignment(MCSymbol *Symbol, const MCExpr *Value) {
613   visitUsedExpr(*Value);
614   Symbol->setVariableValue(Value);
615 
616   MCTargetStreamer *TS = getTargetStreamer();
617   if (TS)
618     TS->emitAssignment(Symbol, Value);
619 }
620 
621 void MCStreamer::visitUsedSymbol(const MCSymbol &Sym) {
622 }
623 
624 void MCStreamer::visitUsedExpr(const MCExpr &Expr) {
625   switch (Expr.getKind()) {
626   case MCExpr::Target:
627     cast<MCTargetExpr>(Expr).visitUsedExpr(*this);
628     break;
629 
630   case MCExpr::Constant:
631     break;
632 
633   case MCExpr::Binary: {
634     const MCBinaryExpr &BE = cast<MCBinaryExpr>(Expr);
635     visitUsedExpr(*BE.getLHS());
636     visitUsedExpr(*BE.getRHS());
637     break;
638   }
639 
640   case MCExpr::SymbolRef:
641     visitUsedSymbol(cast<MCSymbolRefExpr>(Expr).getSymbol());
642     break;
643 
644   case MCExpr::Unary:
645     visitUsedExpr(*cast<MCUnaryExpr>(Expr).getSubExpr());
646     break;
647   }
648 }
649 
650 void MCStreamer::EmitInstruction(const MCInst &Inst,
651                                  const MCSubtargetInfo &STI) {
652   // Scan for values.
653   for (unsigned i = Inst.getNumOperands(); i--;)
654     if (Inst.getOperand(i).isExpr())
655       visitUsedExpr(*Inst.getOperand(i).getExpr());
656 }
657 
658 void MCStreamer::EmitAssemblerFlag(MCAssemblerFlag Flag) {}
659 void MCStreamer::EmitThumbFunc(MCSymbol *Func) {}
660 void MCStreamer::EmitSymbolDesc(MCSymbol *Symbol, unsigned DescValue) {}
661 void MCStreamer::BeginCOFFSymbolDef(const MCSymbol *Symbol) {}
662 void MCStreamer::EndCOFFSymbolDef() {}
663 void MCStreamer::EmitFileDirective(StringRef Filename) {}
664 void MCStreamer::EmitCOFFSymbolStorageClass(int StorageClass) {}
665 void MCStreamer::EmitCOFFSymbolType(int Type) {}
666 void MCStreamer::EmitELFSize(MCSymbol *Symbol, const MCExpr *Value) {}
667 void MCStreamer::EmitLocalCommonSymbol(MCSymbol *Symbol, uint64_t Size,
668                                        unsigned ByteAlignment) {}
669 void MCStreamer::EmitTBSSSymbol(const MCSection *Section, MCSymbol *Symbol,
670                                 uint64_t Size, unsigned ByteAlignment) {}
671 void MCStreamer::ChangeSection(const MCSection *, const MCExpr *) {}
672 void MCStreamer::EmitWeakReference(MCSymbol *Alias, const MCSymbol *Symbol) {}
673 void MCStreamer::EmitBytes(StringRef Data) {}
674 void MCStreamer::EmitValueImpl(const MCExpr *Value, unsigned Size,
675                                const SMLoc &Loc) {
676   visitUsedExpr(*Value);
677 }
678 void MCStreamer::EmitULEB128Value(const MCExpr *Value) {}
679 void MCStreamer::EmitSLEB128Value(const MCExpr *Value) {}
680 void MCStreamer::EmitValueToAlignment(unsigned ByteAlignment, int64_t Value,
681                                       unsigned ValueSize,
682                                       unsigned MaxBytesToEmit) {}
683 void MCStreamer::EmitCodeAlignment(unsigned ByteAlignment,
684                                    unsigned MaxBytesToEmit) {}
685 bool MCStreamer::EmitValueToOffset(const MCExpr *Offset, unsigned char Value) {
686   return false;
687 }
688 void MCStreamer::EmitBundleAlignMode(unsigned AlignPow2) {}
689 void MCStreamer::EmitBundleLock(bool AlignToEnd) {}
690 void MCStreamer::FinishImpl() {}
691 void MCStreamer::EmitBundleUnlock() {}
692