LLVM  8.0.1
WinException.cpp
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1 //===-- CodeGen/AsmPrinter/WinException.cpp - Dwarf Exception Impl ------===//
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 contains support for writing Win64 exception info into asm files.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "WinException.h"
15 #include "llvm/ADT/Twine.h"
16 #include "llvm/BinaryFormat/COFF.h"
26 #include "llvm/IR/DataLayout.h"
27 #include "llvm/IR/Mangler.h"
28 #include "llvm/IR/Module.h"
29 #include "llvm/MC/MCAsmInfo.h"
30 #include "llvm/MC/MCContext.h"
31 #include "llvm/MC/MCExpr.h"
32 #include "llvm/MC/MCSection.h"
33 #include "llvm/MC/MCStreamer.h"
34 #include "llvm/MC/MCSymbol.h"
39 using namespace llvm;
40 
42  // MSVC's EH tables are always composed of 32-bit words. All known 64-bit
43  // platforms use an imagerel32 relocation to refer to symbols.
44  useImageRel32 = (A->getDataLayout().getPointerSizeInBits() == 64);
45  isAArch64 = Asm->TM.getTargetTriple().isAArch64();
46 }
47 
49 
50 /// endModule - Emit all exception information that should come after the
51 /// content.
53  auto &OS = *Asm->OutStreamer;
54  const Module *M = MMI->getModule();
55  for (const Function &F : *M)
56  if (F.hasFnAttribute("safeseh"))
57  OS.EmitCOFFSafeSEH(Asm->getSymbol(&F));
58 }
59 
61  shouldEmitMoves = shouldEmitPersonality = shouldEmitLSDA = false;
62 
63  // If any landing pads survive, we need an EH table.
64  bool hasLandingPads = !MF->getLandingPads().empty();
65  bool hasEHFunclets = MF->hasEHFunclets();
66 
67  const Function &F = MF->getFunction();
68 
69  shouldEmitMoves = Asm->needsSEHMoves() && MF->hasWinCFI();
70 
72  unsigned PerEncoding = TLOF.getPersonalityEncoding();
73 
75  const Function *PerFn = nullptr;
76  if (F.hasPersonalityFn()) {
78  Per = classifyEHPersonality(PerFn);
79  }
80 
81  bool forceEmitPersonality = F.hasPersonalityFn() &&
82  !isNoOpWithoutInvoke(Per) &&
84 
85  shouldEmitPersonality =
86  forceEmitPersonality || ((hasLandingPads || hasEHFunclets) &&
87  PerEncoding != dwarf::DW_EH_PE_omit && PerFn);
88 
89  unsigned LSDAEncoding = TLOF.getLSDAEncoding();
90  shouldEmitLSDA = shouldEmitPersonality &&
91  LSDAEncoding != dwarf::DW_EH_PE_omit;
92 
93  // If we're not using CFI, we don't want the CFI or the personality, but we
94  // might want EH tables if we had EH pads.
95  if (!Asm->MAI->usesWindowsCFI()) {
96  if (Per == EHPersonality::MSVC_X86SEH && !hasEHFunclets) {
97  // If this is 32-bit SEH and we don't have any funclets (really invokes),
98  // make sure we emit the parent offset label. Some unreferenced filter
99  // functions may still refer to it.
100  const WinEHFuncInfo &FuncInfo = *MF->getWinEHFuncInfo();
101  StringRef FLinkageName =
103  emitEHRegistrationOffsetLabel(FuncInfo, FLinkageName);
104  }
105  shouldEmitLSDA = hasEHFunclets;
106  shouldEmitPersonality = false;
107  return;
108  }
109 
111 }
112 
113 /// endFunction - Gather and emit post-function exception information.
114 ///
116  if (!shouldEmitPersonality && !shouldEmitMoves && !shouldEmitLSDA)
117  return;
118 
119  const Function &F = MF->getFunction();
121  if (F.hasPersonalityFn())
123 
124  // Get rid of any dead landing pads if we're not using funclets. In funclet
125  // schemes, the landing pad is not actually reachable. It only exists so
126  // that we can emit the right table data.
127  if (!isFuncletEHPersonality(Per)) {
128  MachineFunction *NonConstMF = const_cast<MachineFunction*>(MF);
129  NonConstMF->tidyLandingPads();
130  }
131 
132  endFunclet();
133 
134  // endFunclet will emit the necessary .xdata tables for x64 SEH.
135  if (Per == EHPersonality::MSVC_Win64SEH && MF->hasEHFunclets())
136  return;
137 
138  if (shouldEmitPersonality || shouldEmitLSDA) {
139  Asm->OutStreamer->PushSection();
140 
141  // Just switch sections to the right xdata section.
142  MCSection *XData = Asm->OutStreamer->getAssociatedXDataSection(
143  Asm->OutStreamer->getCurrentSectionOnly());
144  Asm->OutStreamer->SwitchSection(XData);
145 
146  // Emit the tables appropriate to the personality function in use. If we
147  // don't recognize the personality, assume it uses an Itanium-style LSDA.
148  if (Per == EHPersonality::MSVC_Win64SEH)
149  emitCSpecificHandlerTable(MF);
150  else if (Per == EHPersonality::MSVC_X86SEH)
151  emitExceptHandlerTable(MF);
152  else if (Per == EHPersonality::MSVC_CXX)
153  emitCXXFrameHandler3Table(MF);
154  else if (Per == EHPersonality::CoreCLR)
155  emitCLRExceptionTable(MF);
156  else
158 
159  Asm->OutStreamer->PopSection();
160  }
161 }
162 
163 /// Retrieve the MCSymbol for a GlobalValue or MachineBasicBlock.
165  const MachineBasicBlock *MBB) {
166  if (!MBB)
167  return nullptr;
168 
169  assert(MBB->isEHFuncletEntry());
170 
171  // Give catches and cleanups a name based off of their parent function and
172  // their funclet entry block's number.
173  const MachineFunction *MF = MBB->getParent();
174  const Function &F = MF->getFunction();
176  MCContext &Ctx = MF->getContext();
177  StringRef HandlerPrefix = MBB->isCleanupFuncletEntry() ? "dtor" : "catch";
178  return Ctx.getOrCreateSymbol("?" + HandlerPrefix + "$" +
179  Twine(MBB->getNumber()) + "@?0?" +
180  FuncLinkageName + "@4HA");
181 }
182 
184  MCSymbol *Sym) {
185  CurrentFuncletEntry = &MBB;
186 
187  const Function &F = Asm->MF->getFunction();
188  // If a symbol was not provided for the funclet, invent one.
189  if (!Sym) {
190  Sym = getMCSymbolForMBB(Asm, &MBB);
191 
192  // Describe our funclet symbol as a function with internal linkage.
193  Asm->OutStreamer->BeginCOFFSymbolDef(Sym);
194  Asm->OutStreamer->EmitCOFFSymbolStorageClass(COFF::IMAGE_SYM_CLASS_STATIC);
195  Asm->OutStreamer->EmitCOFFSymbolType(COFF::IMAGE_SYM_DTYPE_FUNCTION
197  Asm->OutStreamer->EndCOFFSymbolDef();
198 
199  // We want our funclet's entry point to be aligned such that no nops will be
200  // present after the label.
202  &F);
203 
204  // Now that we've emitted the alignment directive, point at our funclet.
205  Asm->OutStreamer->EmitLabel(Sym);
206  }
207 
208  // Mark 'Sym' as starting our funclet.
209  if (shouldEmitMoves || shouldEmitPersonality) {
210  CurrentFuncletTextSection = Asm->OutStreamer->getCurrentSectionOnly();
211  Asm->OutStreamer->EmitWinCFIStartProc(Sym);
212  }
213 
214  if (shouldEmitPersonality) {
216  const Function *PerFn = nullptr;
217 
218  // Determine which personality routine we are using for this funclet.
219  if (F.hasPersonalityFn())
220  PerFn = dyn_cast<Function>(F.getPersonalityFn()->stripPointerCasts());
221  const MCSymbol *PersHandlerSym =
222  TLOF.getCFIPersonalitySymbol(PerFn, Asm->TM, MMI);
223 
224  // Do not emit a .seh_handler directives for cleanup funclets.
225  // FIXME: This means cleanup funclets cannot handle exceptions. Given that
226  // Clang doesn't produce EH constructs inside cleanup funclets and LLVM's
227  // inliner doesn't allow inlining them, this isn't a major problem in
228  // practice.
229  if (!CurrentFuncletEntry->isCleanupFuncletEntry())
230  Asm->OutStreamer->EmitWinEHHandler(PersHandlerSym, true, true);
231  }
232 }
233 
235  // No funclet to process? Great, we have nothing to do.
236  if (!CurrentFuncletEntry)
237  return;
238 
239  const MachineFunction *MF = Asm->MF;
240  if (shouldEmitMoves || shouldEmitPersonality) {
241  const Function &F = MF->getFunction();
243  if (F.hasPersonalityFn())
245 
246  // On funclet exit, we emit a fake "function" end marker, so that the call
247  // to EmitWinEHHandlerData below can calculate the size of the funclet or
248  // function.
249  if (isAArch64) {
250  Asm->OutStreamer->SwitchSection(CurrentFuncletTextSection);
251  Asm->OutStreamer->EmitWinCFIFuncletOrFuncEnd();
252  MCSection *XData = Asm->OutStreamer->getAssociatedXDataSection(
253  Asm->OutStreamer->getCurrentSectionOnly());
254  Asm->OutStreamer->SwitchSection(XData);
255  }
256 
257  // Emit an UNWIND_INFO struct describing the prologue.
258  Asm->OutStreamer->EmitWinEHHandlerData();
259 
260  if (Per == EHPersonality::MSVC_CXX && shouldEmitPersonality &&
261  !CurrentFuncletEntry->isCleanupFuncletEntry()) {
262  // If this is a C++ catch funclet (or the parent function),
263  // emit a reference to the LSDA for the parent function.
265  MCSymbol *FuncInfoXData = Asm->OutContext.getOrCreateSymbol(
266  Twine("$cppxdata$", FuncLinkageName));
267  Asm->OutStreamer->EmitValue(create32bitRef(FuncInfoXData), 4);
268  } else if (Per == EHPersonality::MSVC_Win64SEH && MF->hasEHFunclets() &&
269  !CurrentFuncletEntry->isEHFuncletEntry()) {
270  // If this is the parent function in Win64 SEH, emit the LSDA immediately
271  // following .seh_handlerdata.
272  emitCSpecificHandlerTable(MF);
273  }
274 
275  // Switch back to the funclet start .text section now that we are done
276  // writing to .xdata, and emit an .seh_endproc directive to mark the end of
277  // the function.
278  Asm->OutStreamer->SwitchSection(CurrentFuncletTextSection);
279  Asm->OutStreamer->EmitWinCFIEndProc();
280  }
281 
282  // Let's make sure we don't try to end the same funclet twice.
283  CurrentFuncletEntry = nullptr;
284 }
285 
286 const MCExpr *WinException::create32bitRef(const MCSymbol *Value) {
287  if (!Value)
289  return MCSymbolRefExpr::create(Value, useImageRel32
292  Asm->OutContext);
293 }
294 
295 const MCExpr *WinException::create32bitRef(const GlobalValue *GV) {
296  if (!GV)
298  return create32bitRef(Asm->getSymbol(GV));
299 }
300 
301 const MCExpr *WinException::getLabel(const MCSymbol *Label) {
302  if (isAArch64)
304  Asm->OutContext);
305  return MCBinaryExpr::createAdd(create32bitRef(Label),
307  Asm->OutContext);
308 }
309 
310 const MCExpr *WinException::getOffset(const MCSymbol *OffsetOf,
311  const MCSymbol *OffsetFrom) {
315 }
316 
317 const MCExpr *WinException::getOffsetPlusOne(const MCSymbol *OffsetOf,
318  const MCSymbol *OffsetFrom) {
319  return MCBinaryExpr::createAdd(getOffset(OffsetOf, OffsetFrom),
321  Asm->OutContext);
322 }
323 
324 int WinException::getFrameIndexOffset(int FrameIndex,
325  const WinEHFuncInfo &FuncInfo) {
327  unsigned UnusedReg;
328  if (Asm->MAI->usesWindowsCFI()) {
329  int Offset =
331  /*IgnoreSPUpdates*/ true);
332  assert(UnusedReg ==
333  Asm->MF->getSubtarget()
336  return Offset;
337  }
338 
339  // For 32-bit, offsets should be relative to the end of the EH registration
340  // node. For 64-bit, it's relative to SP at the end of the prologue.
341  assert(FuncInfo.EHRegNodeEndOffset != INT_MAX);
342  int Offset = TFI.getFrameIndexReference(*Asm->MF, FrameIndex, UnusedReg);
343  Offset += FuncInfo.EHRegNodeEndOffset;
344  return Offset;
345 }
346 
347 namespace {
348 
349 /// Top-level state used to represent unwind to caller
350 const int NullState = -1;
351 
352 struct InvokeStateChange {
353  /// EH Label immediately after the last invoke in the previous state, or
354  /// nullptr if the previous state was the null state.
355  const MCSymbol *PreviousEndLabel;
356 
357  /// EH label immediately before the first invoke in the new state, or nullptr
358  /// if the new state is the null state.
359  const MCSymbol *NewStartLabel;
360 
361  /// State of the invoke following NewStartLabel, or NullState to indicate
362  /// the presence of calls which may unwind to caller.
363  int NewState;
364 };
365 
366 /// Iterator that reports all the invoke state changes in a range of machine
367 /// basic blocks. Changes to the null state are reported whenever a call that
368 /// may unwind to caller is encountered. The MBB range is expected to be an
369 /// entire function or funclet, and the start and end of the range are treated
370 /// as being in the NullState even if there's not an unwind-to-caller call
371 /// before the first invoke or after the last one (i.e., the first state change
372 /// reported is the first change to something other than NullState, and a
373 /// change back to NullState is always reported at the end of iteration).
374 class InvokeStateChangeIterator {
375  InvokeStateChangeIterator(const WinEHFuncInfo &EHInfo,
379  int BaseState)
380  : EHInfo(EHInfo), MFI(MFI), MFE(MFE), MBBI(MBBI), BaseState(BaseState) {
381  LastStateChange.PreviousEndLabel = nullptr;
382  LastStateChange.NewStartLabel = nullptr;
383  LastStateChange.NewState = BaseState;
384  scan();
385  }
386 
387 public:
389  range(const WinEHFuncInfo &EHInfo, MachineFunction::const_iterator Begin,
390  MachineFunction::const_iterator End, int BaseState = NullState) {
391  // Reject empty ranges to simplify bookkeeping by ensuring that we can get
392  // the end of the last block.
393  assert(Begin != End);
394  auto BlockBegin = Begin->begin();
395  auto BlockEnd = std::prev(End)->end();
396  return make_range(
397  InvokeStateChangeIterator(EHInfo, Begin, End, BlockBegin, BaseState),
398  InvokeStateChangeIterator(EHInfo, End, End, BlockEnd, BaseState));
399  }
400 
401  // Iterator methods.
402  bool operator==(const InvokeStateChangeIterator &O) const {
403  assert(BaseState == O.BaseState);
404  // Must be visiting same block.
405  if (MFI != O.MFI)
406  return false;
407  // Must be visiting same isntr.
408  if (MBBI != O.MBBI)
409  return false;
410  // At end of block/instr iteration, we can still have two distinct states:
411  // one to report the final EndLabel, and another indicating the end of the
412  // state change iteration. Check for CurrentEndLabel equality to
413  // distinguish these.
414  return CurrentEndLabel == O.CurrentEndLabel;
415  }
416 
417  bool operator!=(const InvokeStateChangeIterator &O) const {
418  return !operator==(O);
419  }
420  InvokeStateChange &operator*() { return LastStateChange; }
421  InvokeStateChange *operator->() { return &LastStateChange; }
422  InvokeStateChangeIterator &operator++() { return scan(); }
423 
424 private:
425  InvokeStateChangeIterator &scan();
426 
427  const WinEHFuncInfo &EHInfo;
428  const MCSymbol *CurrentEndLabel = nullptr;
432  InvokeStateChange LastStateChange;
433  bool VisitingInvoke = false;
434  int BaseState;
435 };
436 
437 } // end anonymous namespace
438 
439 InvokeStateChangeIterator &InvokeStateChangeIterator::scan() {
440  bool IsNewBlock = false;
441  for (; MFI != MFE; ++MFI, IsNewBlock = true) {
442  if (IsNewBlock)
443  MBBI = MFI->begin();
444  for (auto MBBE = MFI->end(); MBBI != MBBE; ++MBBI) {
445  const MachineInstr &MI = *MBBI;
446  if (!VisitingInvoke && LastStateChange.NewState != BaseState &&
448  // Indicate a change of state to the null state. We don't have
449  // start/end EH labels handy but the caller won't expect them for
450  // null state regions.
451  LastStateChange.PreviousEndLabel = CurrentEndLabel;
452  LastStateChange.NewStartLabel = nullptr;
453  LastStateChange.NewState = BaseState;
454  CurrentEndLabel = nullptr;
455  // Don't re-visit this instr on the next scan
456  ++MBBI;
457  return *this;
458  }
459 
460  // All other state changes are at EH labels before/after invokes.
461  if (!MI.isEHLabel())
462  continue;
463  MCSymbol *Label = MI.getOperand(0).getMCSymbol();
464  if (Label == CurrentEndLabel) {
465  VisitingInvoke = false;
466  continue;
467  }
468  auto InvokeMapIter = EHInfo.LabelToStateMap.find(Label);
469  // Ignore EH labels that aren't the ones inserted before an invoke
470  if (InvokeMapIter == EHInfo.LabelToStateMap.end())
471  continue;
472  auto &StateAndEnd = InvokeMapIter->second;
473  int NewState = StateAndEnd.first;
474  // Keep track of the fact that we're between EH start/end labels so
475  // we know not to treat the inoke we'll see as unwinding to caller.
476  VisitingInvoke = true;
477  if (NewState == LastStateChange.NewState) {
478  // The state isn't actually changing here. Record the new end and
479  // keep going.
480  CurrentEndLabel = StateAndEnd.second;
481  continue;
482  }
483  // Found a state change to report
484  LastStateChange.PreviousEndLabel = CurrentEndLabel;
485  LastStateChange.NewStartLabel = Label;
486  LastStateChange.NewState = NewState;
487  // Start keeping track of the new current end
488  CurrentEndLabel = StateAndEnd.second;
489  // Don't re-visit this instr on the next scan
490  ++MBBI;
491  return *this;
492  }
493  }
494  // Iteration hit the end of the block range.
495  if (LastStateChange.NewState != BaseState) {
496  // Report the end of the last new state
497  LastStateChange.PreviousEndLabel = CurrentEndLabel;
498  LastStateChange.NewStartLabel = nullptr;
499  LastStateChange.NewState = BaseState;
500  // Leave CurrentEndLabel non-null to distinguish this state from end.
501  assert(CurrentEndLabel != nullptr);
502  return *this;
503  }
504  // We've reported all state changes and hit the end state.
505  CurrentEndLabel = nullptr;
506  return *this;
507 }
508 
509 /// Emit the language-specific data that __C_specific_handler expects. This
510 /// handler lives in the x64 Microsoft C runtime and allows catching or cleaning
511 /// up after faults with __try, __except, and __finally. The typeinfo values
512 /// are not really RTTI data, but pointers to filter functions that return an
513 /// integer (1, 0, or -1) indicating how to handle the exception. For __finally
514 /// blocks and other cleanups, the landing pad label is zero, and the filter
515 /// function is actually a cleanup handler with the same prototype. A catch-all
516 /// entry is modeled with a null filter function field and a non-zero landing
517 /// pad label.
518 ///
519 /// Possible filter function return values:
520 /// EXCEPTION_EXECUTE_HANDLER (1):
521 /// Jump to the landing pad label after cleanups.
522 /// EXCEPTION_CONTINUE_SEARCH (0):
523 /// Continue searching this table or continue unwinding.
524 /// EXCEPTION_CONTINUE_EXECUTION (-1):
525 /// Resume execution at the trapping PC.
526 ///
527 /// Inferred table structure:
528 /// struct Table {
529 /// int NumEntries;
530 /// struct Entry {
531 /// imagerel32 LabelStart;
532 /// imagerel32 LabelEnd;
533 /// imagerel32 FilterOrFinally; // One means catch-all.
534 /// imagerel32 LabelLPad; // Zero means __finally.
535 /// } Entries[NumEntries];
536 /// };
537 void WinException::emitCSpecificHandlerTable(const MachineFunction *MF) {
538  auto &OS = *Asm->OutStreamer;
539  MCContext &Ctx = Asm->OutContext;
540  const WinEHFuncInfo &FuncInfo = *MF->getWinEHFuncInfo();
541 
542  bool VerboseAsm = OS.isVerboseAsm();
543  auto AddComment = [&](const Twine &Comment) {
544  if (VerboseAsm)
545  OS.AddComment(Comment);
546  };
547 
548  if (!isAArch64) {
549  // Emit a label assignment with the SEH frame offset so we can use it for
550  // llvm.eh.recoverfp.
551  StringRef FLinkageName =
553  MCSymbol *ParentFrameOffset =
554  Ctx.getOrCreateParentFrameOffsetSymbol(FLinkageName);
555  const MCExpr *MCOffset =
557  Asm->OutStreamer->EmitAssignment(ParentFrameOffset, MCOffset);
558  }
559 
560  // Use the assembler to compute the number of table entries through label
561  // difference and division.
562  MCSymbol *TableBegin =
563  Ctx.createTempSymbol("lsda_begin", /*AlwaysAddSuffix=*/true);
564  MCSymbol *TableEnd =
565  Ctx.createTempSymbol("lsda_end", /*AlwaysAddSuffix=*/true);
566  const MCExpr *LabelDiff = getOffset(TableEnd, TableBegin);
567  const MCExpr *EntrySize = MCConstantExpr::create(16, Ctx);
568  const MCExpr *EntryCount = MCBinaryExpr::createDiv(LabelDiff, EntrySize, Ctx);
569  AddComment("Number of call sites");
570  OS.EmitValue(EntryCount, 4);
571 
572  OS.EmitLabel(TableBegin);
573 
574  // Iterate over all the invoke try ranges. Unlike MSVC, LLVM currently only
575  // models exceptions from invokes. LLVM also allows arbitrary reordering of
576  // the code, so our tables end up looking a bit different. Rather than
577  // trying to match MSVC's tables exactly, we emit a denormalized table. For
578  // each range of invokes in the same state, we emit table entries for all
579  // the actions that would be taken in that state. This means our tables are
580  // slightly bigger, which is OK.
581  const MCSymbol *LastStartLabel = nullptr;
582  int LastEHState = -1;
583  // Break out before we enter into a finally funclet.
584  // FIXME: We need to emit separate EH tables for cleanups.
586  MachineFunction::const_iterator Stop = std::next(MF->begin());
587  while (Stop != End && !Stop->isEHFuncletEntry())
588  ++Stop;
589  for (const auto &StateChange :
590  InvokeStateChangeIterator::range(FuncInfo, MF->begin(), Stop)) {
591  // Emit all the actions for the state we just transitioned out of
592  // if it was not the null state
593  if (LastEHState != -1)
594  emitSEHActionsForRange(FuncInfo, LastStartLabel,
595  StateChange.PreviousEndLabel, LastEHState);
596  LastStartLabel = StateChange.NewStartLabel;
597  LastEHState = StateChange.NewState;
598  }
599 
600  OS.EmitLabel(TableEnd);
601 }
602 
603 void WinException::emitSEHActionsForRange(const WinEHFuncInfo &FuncInfo,
604  const MCSymbol *BeginLabel,
605  const MCSymbol *EndLabel, int State) {
606  auto &OS = *Asm->OutStreamer;
607  MCContext &Ctx = Asm->OutContext;
608  bool VerboseAsm = OS.isVerboseAsm();
609  auto AddComment = [&](const Twine &Comment) {
610  if (VerboseAsm)
611  OS.AddComment(Comment);
612  };
613 
614  assert(BeginLabel && EndLabel);
615  while (State != -1) {
616  const SEHUnwindMapEntry &UME = FuncInfo.SEHUnwindMap[State];
617  const MCExpr *FilterOrFinally;
618  const MCExpr *ExceptOrNull;
619  auto *Handler = UME.Handler.get<MachineBasicBlock *>();
620  if (UME.IsFinally) {
621  FilterOrFinally = create32bitRef(getMCSymbolForMBB(Asm, Handler));
622  ExceptOrNull = MCConstantExpr::create(0, Ctx);
623  } else {
624  // For an except, the filter can be 1 (catch-all) or a function
625  // label.
626  FilterOrFinally = UME.Filter ? create32bitRef(UME.Filter)
627  : MCConstantExpr::create(1, Ctx);
628  ExceptOrNull = create32bitRef(Handler->getSymbol());
629  }
630 
631  AddComment("LabelStart");
632  OS.EmitValue(getLabel(BeginLabel), 4);
633  AddComment("LabelEnd");
634  OS.EmitValue(getLabel(EndLabel), 4);
635  AddComment(UME.IsFinally ? "FinallyFunclet" : UME.Filter ? "FilterFunction"
636  : "CatchAll");
637  OS.EmitValue(FilterOrFinally, 4);
638  AddComment(UME.IsFinally ? "Null" : "ExceptionHandler");
639  OS.EmitValue(ExceptOrNull, 4);
640 
641  assert(UME.ToState < State && "states should decrease");
642  State = UME.ToState;
643  }
644 }
645 
646 void WinException::emitCXXFrameHandler3Table(const MachineFunction *MF) {
647  const Function &F = MF->getFunction();
648  auto &OS = *Asm->OutStreamer;
649  const WinEHFuncInfo &FuncInfo = *MF->getWinEHFuncInfo();
650 
652 
654  MCSymbol *FuncInfoXData = nullptr;
655  if (shouldEmitPersonality) {
656  // If we're 64-bit, emit a pointer to the C++ EH data, and build a map from
657  // IPs to state numbers.
658  FuncInfoXData =
659  Asm->OutContext.getOrCreateSymbol(Twine("$cppxdata$", FuncLinkageName));
660  computeIP2StateTable(MF, FuncInfo, IPToStateTable);
661  } else {
662  FuncInfoXData = Asm->OutContext.getOrCreateLSDASymbol(FuncLinkageName);
663  }
664 
665  int UnwindHelpOffset = 0;
666  if (Asm->MAI->usesWindowsCFI())
667  UnwindHelpOffset =
668  getFrameIndexOffset(FuncInfo.UnwindHelpFrameIdx, FuncInfo);
669 
670  MCSymbol *UnwindMapXData = nullptr;
671  MCSymbol *TryBlockMapXData = nullptr;
672  MCSymbol *IPToStateXData = nullptr;
673  if (!FuncInfo.CxxUnwindMap.empty())
674  UnwindMapXData = Asm->OutContext.getOrCreateSymbol(
675  Twine("$stateUnwindMap$", FuncLinkageName));
676  if (!FuncInfo.TryBlockMap.empty())
677  TryBlockMapXData =
678  Asm->OutContext.getOrCreateSymbol(Twine("$tryMap$", FuncLinkageName));
679  if (!IPToStateTable.empty())
680  IPToStateXData =
681  Asm->OutContext.getOrCreateSymbol(Twine("$ip2state$", FuncLinkageName));
682 
683  bool VerboseAsm = OS.isVerboseAsm();
684  auto AddComment = [&](const Twine &Comment) {
685  if (VerboseAsm)
686  OS.AddComment(Comment);
687  };
688 
689  // FuncInfo {
690  // uint32_t MagicNumber
691  // int32_t MaxState;
692  // UnwindMapEntry *UnwindMap;
693  // uint32_t NumTryBlocks;
694  // TryBlockMapEntry *TryBlockMap;
695  // uint32_t IPMapEntries; // always 0 for x86
696  // IPToStateMapEntry *IPToStateMap; // always 0 for x86
697  // uint32_t UnwindHelp; // non-x86 only
698  // ESTypeList *ESTypeList;
699  // int32_t EHFlags;
700  // }
701  // EHFlags & 1 -> Synchronous exceptions only, no async exceptions.
702  // EHFlags & 2 -> ???
703  // EHFlags & 4 -> The function is noexcept(true), unwinding can't continue.
704  OS.EmitValueToAlignment(4);
705  OS.EmitLabel(FuncInfoXData);
706 
707  AddComment("MagicNumber");
708  OS.EmitIntValue(0x19930522, 4);
709 
710  AddComment("MaxState");
711  OS.EmitIntValue(FuncInfo.CxxUnwindMap.size(), 4);
712 
713  AddComment("UnwindMap");
714  OS.EmitValue(create32bitRef(UnwindMapXData), 4);
715 
716  AddComment("NumTryBlocks");
717  OS.EmitIntValue(FuncInfo.TryBlockMap.size(), 4);
718 
719  AddComment("TryBlockMap");
720  OS.EmitValue(create32bitRef(TryBlockMapXData), 4);
721 
722  AddComment("IPMapEntries");
723  OS.EmitIntValue(IPToStateTable.size(), 4);
724 
725  AddComment("IPToStateXData");
726  OS.EmitValue(create32bitRef(IPToStateXData), 4);
727 
728  if (Asm->MAI->usesWindowsCFI()) {
729  AddComment("UnwindHelp");
730  OS.EmitIntValue(UnwindHelpOffset, 4);
731  }
732 
733  AddComment("ESTypeList");
734  OS.EmitIntValue(0, 4);
735 
736  AddComment("EHFlags");
737  OS.EmitIntValue(1, 4);
738 
739  // UnwindMapEntry {
740  // int32_t ToState;
741  // void (*Action)();
742  // };
743  if (UnwindMapXData) {
744  OS.EmitLabel(UnwindMapXData);
745  for (const CxxUnwindMapEntry &UME : FuncInfo.CxxUnwindMap) {
746  MCSymbol *CleanupSym =
748  AddComment("ToState");
749  OS.EmitIntValue(UME.ToState, 4);
750 
751  AddComment("Action");
752  OS.EmitValue(create32bitRef(CleanupSym), 4);
753  }
754  }
755 
756  // TryBlockMap {
757  // int32_t TryLow;
758  // int32_t TryHigh;
759  // int32_t CatchHigh;
760  // int32_t NumCatches;
761  // HandlerType *HandlerArray;
762  // };
763  if (TryBlockMapXData) {
764  OS.EmitLabel(TryBlockMapXData);
765  SmallVector<MCSymbol *, 1> HandlerMaps;
766  for (size_t I = 0, E = FuncInfo.TryBlockMap.size(); I != E; ++I) {
767  const WinEHTryBlockMapEntry &TBME = FuncInfo.TryBlockMap[I];
768 
769  MCSymbol *HandlerMapXData = nullptr;
770  if (!TBME.HandlerArray.empty())
771  HandlerMapXData =
772  Asm->OutContext.getOrCreateSymbol(Twine("$handlerMap$")
773  .concat(Twine(I))
774  .concat("$")
775  .concat(FuncLinkageName));
776  HandlerMaps.push_back(HandlerMapXData);
777 
778  // TBMEs should form intervals.
779  assert(0 <= TBME.TryLow && "bad trymap interval");
780  assert(TBME.TryLow <= TBME.TryHigh && "bad trymap interval");
781  assert(TBME.TryHigh < TBME.CatchHigh && "bad trymap interval");
782  assert(TBME.CatchHigh < int(FuncInfo.CxxUnwindMap.size()) &&
783  "bad trymap interval");
784 
785  AddComment("TryLow");
786  OS.EmitIntValue(TBME.TryLow, 4);
787 
788  AddComment("TryHigh");
789  OS.EmitIntValue(TBME.TryHigh, 4);
790 
791  AddComment("CatchHigh");
792  OS.EmitIntValue(TBME.CatchHigh, 4);
793 
794  AddComment("NumCatches");
795  OS.EmitIntValue(TBME.HandlerArray.size(), 4);
796 
797  AddComment("HandlerArray");
798  OS.EmitValue(create32bitRef(HandlerMapXData), 4);
799  }
800 
801  // All funclets use the same parent frame offset currently.
802  unsigned ParentFrameOffset = 0;
803  if (shouldEmitPersonality) {
805  ParentFrameOffset = TFI->getWinEHParentFrameOffset(*MF);
806  }
807 
808  for (size_t I = 0, E = FuncInfo.TryBlockMap.size(); I != E; ++I) {
809  const WinEHTryBlockMapEntry &TBME = FuncInfo.TryBlockMap[I];
810  MCSymbol *HandlerMapXData = HandlerMaps[I];
811  if (!HandlerMapXData)
812  continue;
813  // HandlerType {
814  // int32_t Adjectives;
815  // TypeDescriptor *Type;
816  // int32_t CatchObjOffset;
817  // void (*Handler)();
818  // int32_t ParentFrameOffset; // x64 and AArch64 only
819  // };
820  OS.EmitLabel(HandlerMapXData);
821  for (const WinEHHandlerType &HT : TBME.HandlerArray) {
822  // Get the frame escape label with the offset of the catch object. If
823  // the index is INT_MAX, then there is no catch object, and we should
824  // emit an offset of zero, indicating that no copy will occur.
825  const MCExpr *FrameAllocOffsetRef = nullptr;
826  if (HT.CatchObj.FrameIndex != INT_MAX) {
827  int Offset = getFrameIndexOffset(HT.CatchObj.FrameIndex, FuncInfo);
828  assert(Offset != 0 && "Illegal offset for catch object!");
829  FrameAllocOffsetRef = MCConstantExpr::create(Offset, Asm->OutContext);
830  } else {
831  FrameAllocOffsetRef = MCConstantExpr::create(0, Asm->OutContext);
832  }
833 
834  MCSymbol *HandlerSym =
836 
837  AddComment("Adjectives");
838  OS.EmitIntValue(HT.Adjectives, 4);
839 
840  AddComment("Type");
841  OS.EmitValue(create32bitRef(HT.TypeDescriptor), 4);
842 
843  AddComment("CatchObjOffset");
844  OS.EmitValue(FrameAllocOffsetRef, 4);
845 
846  AddComment("Handler");
847  OS.EmitValue(create32bitRef(HandlerSym), 4);
848 
849  if (shouldEmitPersonality) {
850  AddComment("ParentFrameOffset");
851  OS.EmitIntValue(ParentFrameOffset, 4);
852  }
853  }
854  }
855  }
856 
857  // IPToStateMapEntry {
858  // void *IP;
859  // int32_t State;
860  // };
861  if (IPToStateXData) {
862  OS.EmitLabel(IPToStateXData);
863  for (auto &IPStatePair : IPToStateTable) {
864  AddComment("IP");
865  OS.EmitValue(IPStatePair.first, 4);
866  AddComment("ToState");
867  OS.EmitIntValue(IPStatePair.second, 4);
868  }
869  }
870 }
871 
872 void WinException::computeIP2StateTable(
873  const MachineFunction *MF, const WinEHFuncInfo &FuncInfo,
874  SmallVectorImpl<std::pair<const MCExpr *, int>> &IPToStateTable) {
875 
876  for (MachineFunction::const_iterator FuncletStart = MF->begin(),
877  FuncletEnd = MF->begin(),
878  End = MF->end();
879  FuncletStart != End; FuncletStart = FuncletEnd) {
880  // Find the end of the funclet
881  while (++FuncletEnd != End) {
882  if (FuncletEnd->isEHFuncletEntry()) {
883  break;
884  }
885  }
886 
887  // Don't emit ip2state entries for cleanup funclets. Any interesting
888  // exceptional actions in cleanups must be handled in a separate IR
889  // function.
890  if (FuncletStart->isCleanupFuncletEntry())
891  continue;
892 
893  MCSymbol *StartLabel;
894  int BaseState;
895  if (FuncletStart == MF->begin()) {
896  BaseState = NullState;
897  StartLabel = Asm->getFunctionBegin();
898  } else {
899  auto *FuncletPad =
900  cast<FuncletPadInst>(FuncletStart->getBasicBlock()->getFirstNonPHI());
901  assert(FuncInfo.FuncletBaseStateMap.count(FuncletPad) != 0);
902  BaseState = FuncInfo.FuncletBaseStateMap.find(FuncletPad)->second;
903  StartLabel = getMCSymbolForMBB(Asm, &*FuncletStart);
904  }
905  assert(StartLabel && "need local function start label");
906  IPToStateTable.push_back(
907  std::make_pair(create32bitRef(StartLabel), BaseState));
908 
909  for (const auto &StateChange : InvokeStateChangeIterator::range(
910  FuncInfo, FuncletStart, FuncletEnd, BaseState)) {
911  // Compute the label to report as the start of this entry; use the EH
912  // start label for the invoke if we have one, otherwise (this is a call
913  // which may unwind to our caller and does not have an EH start label, so)
914  // use the previous end label.
915  const MCSymbol *ChangeLabel = StateChange.NewStartLabel;
916  if (!ChangeLabel)
917  ChangeLabel = StateChange.PreviousEndLabel;
918  // Emit an entry indicating that PCs after 'Label' have this EH state.
919  IPToStateTable.push_back(
920  std::make_pair(getLabel(ChangeLabel), StateChange.NewState));
921  // FIXME: assert that NewState is between CatchLow and CatchHigh.
922  }
923  }
924 }
925 
926 void WinException::emitEHRegistrationOffsetLabel(const WinEHFuncInfo &FuncInfo,
927  StringRef FLinkageName) {
928  // Outlined helpers called by the EH runtime need to know the offset of the EH
929  // registration in order to recover the parent frame pointer. Now that we know
930  // we've code generated the parent, we can emit the label assignment that
931  // those helpers use to get the offset of the registration node.
932 
933  // Compute the parent frame offset. The EHRegNodeFrameIndex will be invalid if
934  // after optimization all the invokes were eliminated. We still need to emit
935  // the parent frame offset label, but it should be garbage and should never be
936  // used.
937  int64_t Offset = 0;
938  int FI = FuncInfo.EHRegNodeFrameIndex;
939  if (FI != INT_MAX) {
941  unsigned UnusedReg;
942  // FIXME: getFrameIndexReference needs to match the behavior of
943  // AArch64RegisterInfo::hasBasePointer in which one of the scenarios where
944  // SP is used is if frame size >= 256.
945  Offset = TFI->getFrameIndexReference(*Asm->MF, FI, UnusedReg);
946  }
947 
948  MCContext &Ctx = Asm->OutContext;
949  MCSymbol *ParentFrameOffset =
950  Ctx.getOrCreateParentFrameOffsetSymbol(FLinkageName);
951  Asm->OutStreamer->EmitAssignment(ParentFrameOffset,
952  MCConstantExpr::create(Offset, Ctx));
953 }
954 
955 /// Emit the language-specific data that _except_handler3 and 4 expect. This is
956 /// functionally equivalent to the __C_specific_handler table, except it is
957 /// indexed by state number instead of IP.
958 void WinException::emitExceptHandlerTable(const MachineFunction *MF) {
959  MCStreamer &OS = *Asm->OutStreamer;
960  const Function &F = MF->getFunction();
962 
963  bool VerboseAsm = OS.isVerboseAsm();
964  auto AddComment = [&](const Twine &Comment) {
965  if (VerboseAsm)
966  OS.AddComment(Comment);
967  };
968 
969  const WinEHFuncInfo &FuncInfo = *MF->getWinEHFuncInfo();
970  emitEHRegistrationOffsetLabel(FuncInfo, FLinkageName);
971 
972  // Emit the __ehtable label that we use for llvm.x86.seh.lsda.
973  MCSymbol *LSDALabel = Asm->OutContext.getOrCreateLSDASymbol(FLinkageName);
974  OS.EmitValueToAlignment(4);
975  OS.EmitLabel(LSDALabel);
976 
977  const Function *Per =
979  StringRef PerName = Per->getName();
980  int BaseState = -1;
981  if (PerName == "_except_handler4") {
982  // The LSDA for _except_handler4 starts with this struct, followed by the
983  // scope table:
984  //
985  // struct EH4ScopeTable {
986  // int32_t GSCookieOffset;
987  // int32_t GSCookieXOROffset;
988  // int32_t EHCookieOffset;
989  // int32_t EHCookieXOROffset;
990  // ScopeTableEntry ScopeRecord[];
991  // };
992  //
993  // Offsets are %ebp relative.
994  //
995  // The GS cookie is present only if the function needs stack protection.
996  // GSCookieOffset = -2 means that GS cookie is not used.
997  //
998  // The EH cookie is always present.
999  //
1000  // Check is done the following way:
1001  // (ebp+CookieXOROffset) ^ [ebp+CookieOffset] == _security_cookie
1002 
1003  // Retrieve the Guard Stack slot.
1004  int GSCookieOffset = -2;
1005  const MachineFrameInfo &MFI = MF->getFrameInfo();
1006  if (MFI.hasStackProtectorIndex()) {
1007  unsigned UnusedReg;
1008  const TargetFrameLowering *TFI = MF->getSubtarget().getFrameLowering();
1009  int SSPIdx = MFI.getStackProtectorIndex();
1010  GSCookieOffset = TFI->getFrameIndexReference(*MF, SSPIdx, UnusedReg);
1011  }
1012 
1013  // Retrieve the EH Guard slot.
1014  // TODO(etienneb): Get rid of this value and change it for and assertion.
1015  int EHCookieOffset = 9999;
1016  if (FuncInfo.EHGuardFrameIndex != INT_MAX) {
1017  unsigned UnusedReg;
1018  const TargetFrameLowering *TFI = MF->getSubtarget().getFrameLowering();
1019  int EHGuardIdx = FuncInfo.EHGuardFrameIndex;
1020  EHCookieOffset = TFI->getFrameIndexReference(*MF, EHGuardIdx, UnusedReg);
1021  }
1022 
1023  AddComment("GSCookieOffset");
1024  OS.EmitIntValue(GSCookieOffset, 4);
1025  AddComment("GSCookieXOROffset");
1026  OS.EmitIntValue(0, 4);
1027  AddComment("EHCookieOffset");
1028  OS.EmitIntValue(EHCookieOffset, 4);
1029  AddComment("EHCookieXOROffset");
1030  OS.EmitIntValue(0, 4);
1031  BaseState = -2;
1032  }
1033 
1034  assert(!FuncInfo.SEHUnwindMap.empty());
1035  for (const SEHUnwindMapEntry &UME : FuncInfo.SEHUnwindMap) {
1036  auto *Handler = UME.Handler.get<MachineBasicBlock *>();
1037  const MCSymbol *ExceptOrFinally =
1038  UME.IsFinally ? getMCSymbolForMBB(Asm, Handler) : Handler->getSymbol();
1039  // -1 is usually the base state for "unwind to caller", but for
1040  // _except_handler4 it's -2. Do that replacement here if necessary.
1041  int ToState = UME.ToState == -1 ? BaseState : UME.ToState;
1042  AddComment("ToState");
1043  OS.EmitIntValue(ToState, 4);
1044  AddComment(UME.IsFinally ? "Null" : "FilterFunction");
1045  OS.EmitValue(create32bitRef(UME.Filter), 4);
1046  AddComment(UME.IsFinally ? "FinallyFunclet" : "ExceptionHandler");
1047  OS.EmitValue(create32bitRef(ExceptOrFinally), 4);
1048  }
1049 }
1050 
1051 static int getTryRank(const WinEHFuncInfo &FuncInfo, int State) {
1052  int Rank = 0;
1053  while (State != -1) {
1054  ++Rank;
1055  State = FuncInfo.ClrEHUnwindMap[State].TryParentState;
1056  }
1057  return Rank;
1058 }
1059 
1060 static int getTryAncestor(const WinEHFuncInfo &FuncInfo, int Left, int Right) {
1061  int LeftRank = getTryRank(FuncInfo, Left);
1062  int RightRank = getTryRank(FuncInfo, Right);
1063 
1064  while (LeftRank < RightRank) {
1065  Right = FuncInfo.ClrEHUnwindMap[Right].TryParentState;
1066  --RightRank;
1067  }
1068 
1069  while (RightRank < LeftRank) {
1070  Left = FuncInfo.ClrEHUnwindMap[Left].TryParentState;
1071  --LeftRank;
1072  }
1073 
1074  while (Left != Right) {
1075  Left = FuncInfo.ClrEHUnwindMap[Left].TryParentState;
1076  Right = FuncInfo.ClrEHUnwindMap[Right].TryParentState;
1077  }
1078 
1079  return Left;
1080 }
1081 
1082 void WinException::emitCLRExceptionTable(const MachineFunction *MF) {
1083  // CLR EH "states" are really just IDs that identify handlers/funclets;
1084  // states, handlers, and funclets all have 1:1 mappings between them, and a
1085  // handler/funclet's "state" is its index in the ClrEHUnwindMap.
1086  MCStreamer &OS = *Asm->OutStreamer;
1087  const WinEHFuncInfo &FuncInfo = *MF->getWinEHFuncInfo();
1088  MCSymbol *FuncBeginSym = Asm->getFunctionBegin();
1089  MCSymbol *FuncEndSym = Asm->getFunctionEnd();
1090 
1091  // A ClrClause describes a protected region.
1092  struct ClrClause {
1093  const MCSymbol *StartLabel; // Start of protected region
1094  const MCSymbol *EndLabel; // End of protected region
1095  int State; // Index of handler protecting the protected region
1096  int EnclosingState; // Index of funclet enclosing the protected region
1097  };
1098  SmallVector<ClrClause, 8> Clauses;
1099 
1100  // Build a map from handler MBBs to their corresponding states (i.e. their
1101  // indices in the ClrEHUnwindMap).
1102  int NumStates = FuncInfo.ClrEHUnwindMap.size();
1103  assert(NumStates > 0 && "Don't need exception table!");
1105  for (int State = 0; State < NumStates; ++State) {
1106  MachineBasicBlock *HandlerBlock =
1107  FuncInfo.ClrEHUnwindMap[State].Handler.get<MachineBasicBlock *>();
1108  HandlerStates[HandlerBlock] = State;
1109  // Use this loop through all handlers to verify our assumption (used in
1110  // the MinEnclosingState computation) that enclosing funclets have lower
1111  // state numbers than their enclosed funclets.
1112  assert(FuncInfo.ClrEHUnwindMap[State].HandlerParentState < State &&
1113  "ill-formed state numbering");
1114  }
1115  // Map the main function to the NullState.
1116  HandlerStates[&MF->front()] = NullState;
1117 
1118  // Write out a sentinel indicating the end of the standard (Windows) xdata
1119  // and the start of the additional (CLR) info.
1120  OS.EmitIntValue(0xffffffff, 4);
1121  // Write out the number of funclets
1122  OS.EmitIntValue(NumStates, 4);
1123 
1124  // Walk the machine blocks/instrs, computing and emitting a few things:
1125  // 1. Emit a list of the offsets to each handler entry, in lexical order.
1126  // 2. Compute a map (EndSymbolMap) from each funclet to the symbol at its end.
1127  // 3. Compute the list of ClrClauses, in the required order (inner before
1128  // outer, earlier before later; the order by which a forward scan with
1129  // early termination will find the innermost enclosing clause covering
1130  // a given address).
1131  // 4. A map (MinClauseMap) from each handler index to the index of the
1132  // outermost funclet/function which contains a try clause targeting the
1133  // key handler. This will be used to determine IsDuplicate-ness when
1134  // emitting ClrClauses. The NullState value is used to indicate that the
1135  // top-level function contains a try clause targeting the key handler.
1136  // HandlerStack is a stack of (PendingStartLabel, PendingState) pairs for
1137  // try regions we entered before entering the PendingState try but which
1138  // we haven't yet exited.
1140  // EndSymbolMap and MinClauseMap are maps described above.
1141  std::unique_ptr<MCSymbol *[]> EndSymbolMap(new MCSymbol *[NumStates]);
1142  SmallVector<int, 4> MinClauseMap((size_t)NumStates, NumStates);
1143 
1144  // Visit the root function and each funclet.
1145  for (MachineFunction::const_iterator FuncletStart = MF->begin(),
1146  FuncletEnd = MF->begin(),
1147  End = MF->end();
1148  FuncletStart != End; FuncletStart = FuncletEnd) {
1149  int FuncletState = HandlerStates[&*FuncletStart];
1150  // Find the end of the funclet
1151  MCSymbol *EndSymbol = FuncEndSym;
1152  while (++FuncletEnd != End) {
1153  if (FuncletEnd->isEHFuncletEntry()) {
1154  EndSymbol = getMCSymbolForMBB(Asm, &*FuncletEnd);
1155  break;
1156  }
1157  }
1158  // Emit the function/funclet end and, if this is a funclet (and not the
1159  // root function), record it in the EndSymbolMap.
1160  OS.EmitValue(getOffset(EndSymbol, FuncBeginSym), 4);
1161  if (FuncletState != NullState) {
1162  // Record the end of the handler.
1163  EndSymbolMap[FuncletState] = EndSymbol;
1164  }
1165 
1166  // Walk the state changes in this function/funclet and compute its clauses.
1167  // Funclets always start in the null state.
1168  const MCSymbol *CurrentStartLabel = nullptr;
1169  int CurrentState = NullState;
1170  assert(HandlerStack.empty());
1171  for (const auto &StateChange :
1172  InvokeStateChangeIterator::range(FuncInfo, FuncletStart, FuncletEnd)) {
1173  // Close any try regions we're not still under
1174  int StillPendingState =
1175  getTryAncestor(FuncInfo, CurrentState, StateChange.NewState);
1176  while (CurrentState != StillPendingState) {
1177  assert(CurrentState != NullState &&
1178  "Failed to find still-pending state!");
1179  // Close the pending clause
1180  Clauses.push_back({CurrentStartLabel, StateChange.PreviousEndLabel,
1181  CurrentState, FuncletState});
1182  // Now the next-outer try region is current
1183  CurrentState = FuncInfo.ClrEHUnwindMap[CurrentState].TryParentState;
1184  // Pop the new start label from the handler stack if we've exited all
1185  // inner try regions of the corresponding try region.
1186  if (HandlerStack.back().second == CurrentState)
1187  CurrentStartLabel = HandlerStack.pop_back_val().first;
1188  }
1189 
1190  if (StateChange.NewState != CurrentState) {
1191  // For each clause we're starting, update the MinClauseMap so we can
1192  // know which is the topmost funclet containing a clause targeting
1193  // it.
1194  for (int EnteredState = StateChange.NewState;
1195  EnteredState != CurrentState;
1196  EnteredState =
1197  FuncInfo.ClrEHUnwindMap[EnteredState].TryParentState) {
1198  int &MinEnclosingState = MinClauseMap[EnteredState];
1199  if (FuncletState < MinEnclosingState)
1200  MinEnclosingState = FuncletState;
1201  }
1202  // Save the previous current start/label on the stack and update to
1203  // the newly-current start/state.
1204  HandlerStack.emplace_back(CurrentStartLabel, CurrentState);
1205  CurrentStartLabel = StateChange.NewStartLabel;
1206  CurrentState = StateChange.NewState;
1207  }
1208  }
1209  assert(HandlerStack.empty());
1210  }
1211 
1212  // Now emit the clause info, starting with the number of clauses.
1213  OS.EmitIntValue(Clauses.size(), 4);
1214  for (ClrClause &Clause : Clauses) {
1215  // Emit a CORINFO_EH_CLAUSE :
1216  /*
1217  struct CORINFO_EH_CLAUSE
1218  {
1219  CORINFO_EH_CLAUSE_FLAGS Flags; // actually a CorExceptionFlag
1220  DWORD TryOffset;
1221  DWORD TryLength; // actually TryEndOffset
1222  DWORD HandlerOffset;
1223  DWORD HandlerLength; // actually HandlerEndOffset
1224  union
1225  {
1226  DWORD ClassToken; // use for catch clauses
1227  DWORD FilterOffset; // use for filter clauses
1228  };
1229  };
1230 
1231  enum CORINFO_EH_CLAUSE_FLAGS
1232  {
1233  CORINFO_EH_CLAUSE_NONE = 0,
1234  CORINFO_EH_CLAUSE_FILTER = 0x0001, // This clause is for a filter
1235  CORINFO_EH_CLAUSE_FINALLY = 0x0002, // This clause is a finally clause
1236  CORINFO_EH_CLAUSE_FAULT = 0x0004, // This clause is a fault clause
1237  };
1238  typedef enum CorExceptionFlag
1239  {
1240  COR_ILEXCEPTION_CLAUSE_NONE,
1241  COR_ILEXCEPTION_CLAUSE_FILTER = 0x0001, // This is a filter clause
1242  COR_ILEXCEPTION_CLAUSE_FINALLY = 0x0002, // This is a finally clause
1243  COR_ILEXCEPTION_CLAUSE_FAULT = 0x0004, // This is a fault clause
1244  COR_ILEXCEPTION_CLAUSE_DUPLICATED = 0x0008, // duplicated clause. This
1245  // clause was duplicated
1246  // to a funclet which was
1247  // pulled out of line
1248  } CorExceptionFlag;
1249  */
1250  // Add 1 to the start/end of the EH clause; the IP associated with a
1251  // call when the runtime does its scan is the IP of the next instruction
1252  // (the one to which control will return after the call), so we need
1253  // to add 1 to the end of the clause to cover that offset. We also add
1254  // 1 to the start of the clause to make sure that the ranges reported
1255  // for all clauses are disjoint. Note that we'll need some additional
1256  // logic when machine traps are supported, since in that case the IP
1257  // that the runtime uses is the offset of the faulting instruction
1258  // itself; if such an instruction immediately follows a call but the
1259  // two belong to different clauses, we'll need to insert a nop between
1260  // them so the runtime can distinguish the point to which the call will
1261  // return from the point at which the fault occurs.
1262 
1263  const MCExpr *ClauseBegin =
1264  getOffsetPlusOne(Clause.StartLabel, FuncBeginSym);
1265  const MCExpr *ClauseEnd = getOffsetPlusOne(Clause.EndLabel, FuncBeginSym);
1266 
1267  const ClrEHUnwindMapEntry &Entry = FuncInfo.ClrEHUnwindMap[Clause.State];
1268  MachineBasicBlock *HandlerBlock = Entry.Handler.get<MachineBasicBlock *>();
1269  MCSymbol *BeginSym = getMCSymbolForMBB(Asm, HandlerBlock);
1270  const MCExpr *HandlerBegin = getOffset(BeginSym, FuncBeginSym);
1271  MCSymbol *EndSym = EndSymbolMap[Clause.State];
1272  const MCExpr *HandlerEnd = getOffset(EndSym, FuncBeginSym);
1273 
1274  uint32_t Flags = 0;
1275  switch (Entry.HandlerType) {
1276  case ClrHandlerType::Catch:
1277  // Leaving bits 0-2 clear indicates catch.
1278  break;
1280  Flags |= 1;
1281  break;
1283  Flags |= 2;
1284  break;
1285  case ClrHandlerType::Fault:
1286  Flags |= 4;
1287  break;
1288  }
1289  if (Clause.EnclosingState != MinClauseMap[Clause.State]) {
1290  // This is a "duplicate" clause; the handler needs to be entered from a
1291  // frame above the one holding the invoke.
1292  assert(Clause.EnclosingState > MinClauseMap[Clause.State]);
1293  Flags |= 8;
1294  }
1295  OS.EmitIntValue(Flags, 4);
1296 
1297  // Write the clause start/end
1298  OS.EmitValue(ClauseBegin, 4);
1299  OS.EmitValue(ClauseEnd, 4);
1300 
1301  // Write out the handler start/end
1302  OS.EmitValue(HandlerBegin, 4);
1303  OS.EmitValue(HandlerEnd, 4);
1304 
1305  // Write out the type token or filter offset
1306  assert(Entry.HandlerType != ClrHandlerType::Filter && "NYI: filters");
1307  OS.EmitIntValue(Entry.TypeToken, 4);
1308  }
1309 }
detail::concat_range< ValueT, RangeTs... > concat(RangeTs &&... Ranges)
Concatenated range across two or more ranges.
Definition: STLExtras.h:947
MBBOrBasicBlock Handler
Definition: WinEHFuncInfo.h:83
const TargetLoweringObjectFile & getObjFileLowering() const
Return information about object file lowering.
Definition: AsmPrinter.cpp:212
Instances of this class represent a uniqued identifier for a section in the current translation unit...
Definition: MCSection.h:39
bool usesWindowsCFI() const
Definition: MCAsmInfo.h:584
SmallVector< WinEHHandlerType, 1 > HandlerArray
Definition: WinEHFuncInfo.h:77
GCNRegPressure max(const GCNRegPressure &P1, const GCNRegPressure &P2)
bool isCall(QueryType Type=AnyInBundle) const
Definition: MachineInstr.h:633
std::unique_ptr< MCStreamer > OutStreamer
This is the MCStreamer object for the file we are generating.
Definition: AsmPrinter.h:94
static int getTryAncestor(const WinEHFuncInfo &FuncInfo, int Left, int Right)
static const MCSymbolRefExpr * create(const MCSymbol *Symbol, MCContext &Ctx)
Definition: MCExpr.h:323
MBBOrBasicBlock Cleanup
Definition: WinEHFuncInfo.h:43
This class represents lattice values for constants.
Definition: AllocatorList.h:24
static MCSymbol * getMCSymbolForMBB(AsmPrinter *Asm, const MachineBasicBlock *MBB)
Retrieve the MCSymbol for a GlobalValue or MachineBasicBlock.
MCSymbol - Instances of this class represent a symbol name in the MC file, and MCSymbols are created ...
Definition: MCSymbol.h:42
A Module instance is used to store all the information related to an LLVM module. ...
Definition: Module.h:65
bool hasStackProtectorIndex() const
SmallVector< SEHUnwindMapEntry, 4 > SEHUnwindMap
Definition: WinEHFuncInfo.h:98
virtual int getFrameIndexReference(const MachineFunction &MF, int FI, unsigned &FrameReg) const
getFrameIndexReference - This method should return the base register and offset used to reference a f...
MCContext & OutContext
This is the context for the output file that we are streaming.
Definition: AsmPrinter.h:89
bool isCleanupFuncletEntry() const
Returns true if this is the entry block of a cleanup funclet.
void beginFunclet(const MachineBasicBlock &MBB, MCSymbol *Sym) override
Emit target-specific EH funclet machinery.
DenseMap< const FuncletPadInst *, int > FuncletBaseStateMap
Definition: WinEHFuncInfo.h:93
static bool callToNoUnwindFunction(const MachineInstr *MI)
Return `true&#39; if this is a call to a function marked `nounwind&#39;.
Definition: EHStreamer.cpp:169
virtual const TargetLowering * getTargetLowering() const
MCSymbol * getOrCreateParentFrameOffsetSymbol(StringRef FuncName)
Definition: MCContext.cpp:142
unsigned getPointerSizeInBits(unsigned AS=0) const
Layout pointer size, in bits FIXME: The defaults need to be removed once all of the backends/clients ...
Definition: DataLayout.h:363
F(f)
MachineFunction * MF
The current machine function.
Definition: AsmPrinter.h:97
virtual int getFrameIndexReferencePreferSP(const MachineFunction &MF, int FI, unsigned &FrameReg, bool IgnoreSPUpdates) const
Same as getFrameIndexReference, except that the stack pointer (as opposed to the frame pointer) will ...
union llvm::WinEHHandlerType::@189 CatchObj
The CatchObj starts out life as an LLVM alloca and is eventually turned frame index.
MachineModuleInfo * MMI
Collected machine module information.
Definition: EHStreamer.h:37
MBBOrBasicBlock Handler
Holds the __except or __finally basic block.
Definition: WinEHFuncInfo.h:58
void endModule() override
Emit all exception information that should come after the content.
Emits exception handling directives.
Definition: EHStreamer.h:31
Twine - A lightweight data structure for efficiently representing the concatenation of temporary valu...
Definition: Twine.h:81
bool isAArch64() const
Tests whether the target is AArch64 (little and big endian).
Definition: Triple.h:675
static const MCBinaryExpr * createDiv(const MCExpr *LHS, const MCExpr *RHS, MCContext &Ctx)
Definition: MCExpr.h:471
This class consists of common code factored out of the SmallVector class to reduce code duplication b...
Definition: APFloat.h:42
Base class for the full range of assembler expressions which are needed for parsing.
Definition: MCExpr.h:36
unsigned getAlignment() const
getAlignment - Return the alignment (log2, not bytes) of the function.
The MachineFrameInfo class represents an abstract stack frame until prolog/epilog code is inserted...
APInt operator*(APInt a, uint64_t RHS)
Definition: APInt.h:2091
virtual unsigned getWinEHParentFrameOffset(const MachineFunction &MF) const
int ToState
If unwinding continues through this handler, transition to the handler at this state.
Definition: WinEHFuncInfo.h:50
Context object for machine code objects.
Definition: MCContext.h:63
virtual void AddComment(const Twine &T, bool EOL=true)
Add a textual comment.
Definition: MCStreamer.h:312
static const MCBinaryExpr * createSub(const MCExpr *LHS, const MCExpr *RHS, MCContext &Ctx)
Definition: MCExpr.h:546
MCSymbol * getFunctionBegin() const
Definition: AsmPrinter.h:212
void tidyLandingPads(DenseMap< MCSymbol *, uintptr_t > *LPMap=nullptr, bool TidyIfNoBeginLabels=true)
Remap landing pad labels and remove any deleted landing pads.
bool hasPersonalityFn() const
Check whether this function has a personality function.
Definition: Function.h:702
int getNumber() const
MachineBasicBlocks are uniquely numbered at the function level, unless they&#39;re not in a MachineFuncti...
Type is formed as (base + (derived << SCT_COMPLEX_TYPE_SHIFT))
Definition: COFF.h:266
static const MCBinaryExpr * createAdd(const MCExpr *LHS, const MCExpr *RHS, MCContext &Ctx)
Definition: MCExpr.h:461
void endFunclet() override
virtual void EmitIntValue(uint64_t Value, unsigned Size)
Special case of EmitValue that avoids the client having to pass in a MCExpr for constant integers...
Definition: MCStreamer.cpp:124
void EmitValue(const MCExpr *Value, unsigned Size, SMLoc Loc=SMLoc())
Definition: MCStreamer.cpp:155
Similar to CxxUnwindMapEntry, but supports SEH filters.
Definition: WinEHFuncInfo.h:47
SmallVector< ClrEHUnwindMapEntry, 4 > ClrEHUnwindMap
Definition: WinEHFuncInfo.h:99
Streaming machine code generation interface.
Definition: MCStreamer.h:189
MCSymbol * createTempSymbol(bool CanBeUnnamed=true)
Create and return a new assembler temporary symbol with a unique but unspecified name.
Definition: MCContext.cpp:217
MCSymbol * CurrentFnSym
The symbol for the current function.
Definition: AsmPrinter.h:113
const MCAsmInfo * MAI
Target Asm Printer information.
Definition: AsmPrinter.h:85
const TargetSubtargetInfo & getSubtarget() const
getSubtarget - Return the subtarget for which this machine code is being compiled.
MachineFrameInfo & getFrameInfo()
getFrameInfo - Return the frame info object for the current function.
static GCRegistry::Add< CoreCLRGC > E("coreclr", "CoreCLR-compatible GC")
bool hasEHFunclets() const
WinException(AsmPrinter *A)
void EmitAlignment(unsigned NumBits, const GlobalObject *GV=nullptr) const
Emit an alignment directive to the specified power of two boundary.
unsigned getAlignment() const
Return alignment of the basic block.
TargetMachine & TM
Target machine description.
Definition: AsmPrinter.h:82
int getStackProtectorIndex() const
Return the index for the stack protector object.
This class is intended to be used as a driving class for all asm writers.
Definition: AsmPrinter.h:79
void endFunction(const MachineFunction *) override
Gather and emit post-function exception information.
EHPersonality classifyEHPersonality(const Value *Pers)
See if the given exception handling personality function is one that we understand.
virtual void EmitValueToAlignment(unsigned ByteAlignment, int64_t Value=0, unsigned ValueSize=1, unsigned MaxBytesToEmit=0)
Emit some number of copies of Value until the byte alignment ByteAlignment is reached.
bool isEHLabel() const
Definition: MachineInstr.h:979
const Triple & getTargetTriple() const
T dyn_cast() const
Returns the current pointer if it is of the specified pointer type, otherwises returns null...
Definition: PointerUnion.h:142
const Constant * stripPointerCasts() const
Definition: Constant.h:174
const MachineBasicBlock & front() const
size_t size() const
Definition: SmallVector.h:53
AsmPrinter * Asm
Target of directive emission.
Definition: EHStreamer.h:34
MBBOrBasicBlock Handler
Definition: WinEHFuncInfo.h:70
void beginFunction(const MachineFunction *MF) override
Gather pre-function exception information.
iterator_range< T > make_range(T x, T y)
Convenience function for iterating over sub-ranges.
SmallVector< CxxUnwindMapEntry, 4 > CxxUnwindMap
Definition: WinEHFuncInfo.h:96
const std::vector< LandingPadInfo > & getLandingPads() const
Return a reference to the landing pad info for the current function.
const Function * Filter
Holds the filter expression function.
Definition: WinEHFuncInfo.h:55
Iterator for intrusive lists based on ilist_node.
MCSymbol * getOrCreateLSDASymbol(StringRef FuncName)
Definition: MCContext.cpp:147
bool isFuncletEHPersonality(EHPersonality Pers)
Returns true if this is a personality function that invokes handler funclets (which must return to it...
MCSymbol * getSymbol(const GlobalValue *GV) const
Definition: AsmPrinter.cpp:430
This is a &#39;vector&#39; (really, a variable-sized array), optimized for the case when the array is small...
Definition: SmallVector.h:847
Module.h This file contains the declarations for the Module class.
Information about stack frame layout on the target.
LLVM_NODISCARD T pop_back_val()
Definition: SmallVector.h:381
const WinEHFuncInfo * getWinEHFuncInfo() const
getWinEHFuncInfo - Return information about how the current function uses Windows exception handling...
MCSymbol * getFunctionEnd() const
Definition: AsmPrinter.h:213
const Function & getFunction() const
Return the LLVM function that this machine code represents.
bool needsUnwindTableEntry() const
True if this function needs an unwind table.
Definition: Function.h:573
SmallVector< WinEHTryBlockMapEntry, 4 > TryBlockMap
Definition: WinEHFuncInfo.h:97
A range adaptor for a pair of iterators.
This file contains constants used for implementing Dwarf debug support.
static StringRef dropLLVMManglingEscape(StringRef Name)
If the given string begins with the GlobalValue name mangling escape character &#39;\1&#39;, drop it.
Definition: GlobalValue.h:472
GlobalVariable * TypeDescriptor
Definition: WinEHFuncInfo.h:69
~WinException() override
bool operator!=(uint64_t V1, const APInt &V2)
Definition: APInt.h:1969
Representation of each machine instruction.
Definition: MachineInstr.h:64
const MachineFunction * getParent() const
Return the MachineFunction containing this basic block.
void emplace_back(ArgTypes &&... Args)
Definition: SmallVector.h:652
MCSymbol * getOrCreateSymbol(const Twine &Name)
Lookup the symbol inside with the specified Name.
Definition: MCContext.cpp:123
LLVM_NODISCARD bool empty() const
Definition: SmallVector.h:56
bool isEHFuncletEntry() const
Returns true if this is the entry block of an EH funclet.
StringRef getName() const
Return a constant reference to the value&#39;s name.
Definition: Value.cpp:214
#define I(x, y, z)
Definition: MD5.cpp:58
virtual const TargetFrameLowering * getFrameLowering() const
LLVM_NODISCARD std::enable_if<!is_simple_type< Y >::value, typename cast_retty< X, const Y >::ret_type >::type dyn_cast(const Y &Val)
Definition: Casting.h:323
ClrHandlerType HandlerType
Definition: WinEHFuncInfo.h:88
const Module * getModule() const
static int getTryRank(const WinEHFuncInfo &FuncInfo, int State)
T get() const
Returns the value of the specified pointer type.
Definition: PointerUnion.h:135
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
MCSymbol * emitExceptionTable()
Emit landing pads and actions.
Definition: EHStreamer.cpp:350
MCSymbol * getMCSymbol() const
LLVM Value Representation.
Definition: Value.h:73
Constant * getPersonalityFn() const
Get the personality function associated with this function.
Definition: Function.cpp:1299
unsigned getStackPointerRegisterToSaveRestore() const
If a physical register, this specifies the register that llvm.savestack/llvm.restorestack should save...
virtual void EmitLabel(MCSymbol *Symbol, SMLoc Loc=SMLoc())
Emit a label for Symbol into the current section.
Definition: MCStreamer.cpp:347
const DataLayout & getDataLayout() const
Return information about data layout.
Definition: AsmPrinter.cpp:216
IRTranslator LLVM IR MI
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:49
bool operator==(uint64_t V1, const APInt &V2)
Definition: APInt.h:1967
virtual MCSymbol * getCFIPersonalitySymbol(const GlobalValue *GV, const TargetMachine &TM, MachineModuleInfo *MMI) const
virtual bool isVerboseAsm() const
Return true if this streamer supports verbose assembly and if it is enabled.
Definition: MCStreamer.h:289
const MachineOperand & getOperand(unsigned i) const
Definition: MachineInstr.h:414
bool isNoOpWithoutInvoke(EHPersonality Pers)
Return true if this personality may be safely removed if there are no invoke instructions remaining i...
static const MCConstantExpr * create(int64_t Value, MCContext &Ctx)
Definition: MCExpr.cpp:164
static Expected< BitVector > scan(StringRef &S, StringRef Original)
Definition: GlobPattern.cpp:67
This file describes how to lower LLVM code to machine code.
A function that returns a base type.
Definition: COFF.h:262