LLVM  8.0.0svn
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 }
46 
48 
49 /// endModule - Emit all exception information that should come after the
50 /// content.
52  auto &OS = *Asm->OutStreamer;
53  const Module *M = MMI->getModule();
54  for (const Function &F : *M)
55  if (F.hasFnAttribute("safeseh"))
56  OS.EmitCOFFSafeSEH(Asm->getSymbol(&F));
57 }
58 
60  shouldEmitMoves = shouldEmitPersonality = shouldEmitLSDA = false;
61 
62  // If any landing pads survive, we need an EH table.
63  bool hasLandingPads = !MF->getLandingPads().empty();
64  bool hasEHFunclets = MF->hasEHFunclets();
65 
66  const Function &F = MF->getFunction();
67 
68  shouldEmitMoves = Asm->needsSEHMoves() && MF->hasWinCFI();
69 
71  unsigned PerEncoding = TLOF.getPersonalityEncoding();
72 
74  const Function *PerFn = nullptr;
75  if (F.hasPersonalityFn()) {
77  Per = classifyEHPersonality(PerFn);
78  }
79 
80  bool forceEmitPersonality = F.hasPersonalityFn() &&
81  !isNoOpWithoutInvoke(Per) &&
83 
84  shouldEmitPersonality =
85  forceEmitPersonality || ((hasLandingPads || hasEHFunclets) &&
86  PerEncoding != dwarf::DW_EH_PE_omit && PerFn);
87 
88  unsigned LSDAEncoding = TLOF.getLSDAEncoding();
89  shouldEmitLSDA = shouldEmitPersonality &&
90  LSDAEncoding != dwarf::DW_EH_PE_omit;
91 
92  // If we're not using CFI, we don't want the CFI or the personality, but we
93  // might want EH tables if we had EH pads.
94  if (!Asm->MAI->usesWindowsCFI()) {
95  if (Per == EHPersonality::MSVC_X86SEH && !hasEHFunclets) {
96  // If this is 32-bit SEH and we don't have any funclets (really invokes),
97  // make sure we emit the parent offset label. Some unreferenced filter
98  // functions may still refer to it.
99  const WinEHFuncInfo &FuncInfo = *MF->getWinEHFuncInfo();
100  StringRef FLinkageName =
102  emitEHRegistrationOffsetLabel(FuncInfo, FLinkageName);
103  }
104  shouldEmitLSDA = hasEHFunclets;
105  shouldEmitPersonality = false;
106  return;
107  }
108 
110 }
111 
112 /// endFunction - Gather and emit post-function exception information.
113 ///
115  if (!shouldEmitPersonality && !shouldEmitMoves && !shouldEmitLSDA)
116  return;
117 
118  const Function &F = MF->getFunction();
120  if (F.hasPersonalityFn())
122 
123  // Get rid of any dead landing pads if we're not using funclets. In funclet
124  // schemes, the landing pad is not actually reachable. It only exists so
125  // that we can emit the right table data.
126  if (!isFuncletEHPersonality(Per)) {
127  MachineFunction *NonConstMF = const_cast<MachineFunction*>(MF);
128  NonConstMF->tidyLandingPads();
129  }
130 
131  endFunclet();
132 
133  // endFunclet will emit the necessary .xdata tables for x64 SEH.
134  if (Per == EHPersonality::MSVC_Win64SEH && MF->hasEHFunclets())
135  return;
136 
137  if (shouldEmitPersonality || shouldEmitLSDA) {
138  Asm->OutStreamer->PushSection();
139 
140  // Just switch sections to the right xdata section.
141  MCSection *XData = Asm->OutStreamer->getAssociatedXDataSection(
142  Asm->OutStreamer->getCurrentSectionOnly());
143  Asm->OutStreamer->SwitchSection(XData);
144 
145  // Emit the tables appropriate to the personality function in use. If we
146  // don't recognize the personality, assume it uses an Itanium-style LSDA.
147  if (Per == EHPersonality::MSVC_Win64SEH)
148  emitCSpecificHandlerTable(MF);
149  else if (Per == EHPersonality::MSVC_X86SEH)
150  emitExceptHandlerTable(MF);
151  else if (Per == EHPersonality::MSVC_CXX)
152  emitCXXFrameHandler3Table(MF);
153  else if (Per == EHPersonality::CoreCLR)
154  emitCLRExceptionTable(MF);
155  else
157 
158  Asm->OutStreamer->PopSection();
159  }
160 }
161 
162 /// Retrieve the MCSymbol for a GlobalValue or MachineBasicBlock.
164  const MachineBasicBlock *MBB) {
165  if (!MBB)
166  return nullptr;
167 
168  assert(MBB->isEHFuncletEntry());
169 
170  // Give catches and cleanups a name based off of their parent function and
171  // their funclet entry block's number.
172  const MachineFunction *MF = MBB->getParent();
173  const Function &F = MF->getFunction();
175  MCContext &Ctx = MF->getContext();
176  StringRef HandlerPrefix = MBB->isCleanupFuncletEntry() ? "dtor" : "catch";
177  return Ctx.getOrCreateSymbol("?" + HandlerPrefix + "$" +
178  Twine(MBB->getNumber()) + "@?0?" +
179  FuncLinkageName + "@4HA");
180 }
181 
183  MCSymbol *Sym) {
184  CurrentFuncletEntry = &MBB;
185 
186  const Function &F = Asm->MF->getFunction();
187  // If a symbol was not provided for the funclet, invent one.
188  if (!Sym) {
189  Sym = getMCSymbolForMBB(Asm, &MBB);
190 
191  // Describe our funclet symbol as a function with internal linkage.
192  Asm->OutStreamer->BeginCOFFSymbolDef(Sym);
193  Asm->OutStreamer->EmitCOFFSymbolStorageClass(COFF::IMAGE_SYM_CLASS_STATIC);
194  Asm->OutStreamer->EmitCOFFSymbolType(COFF::IMAGE_SYM_DTYPE_FUNCTION
196  Asm->OutStreamer->EndCOFFSymbolDef();
197 
198  // We want our funclet's entry point to be aligned such that no nops will be
199  // present after the label.
201  &F);
202 
203  // Now that we've emitted the alignment directive, point at our funclet.
204  Asm->OutStreamer->EmitLabel(Sym);
205  }
206 
207  // Mark 'Sym' as starting our funclet.
208  if (shouldEmitMoves || shouldEmitPersonality) {
209  CurrentFuncletTextSection = Asm->OutStreamer->getCurrentSectionOnly();
210  Asm->OutStreamer->EmitWinCFIStartProc(Sym);
211  }
212 
213  if (shouldEmitPersonality) {
215  const Function *PerFn = nullptr;
216 
217  // Determine which personality routine we are using for this funclet.
218  if (F.hasPersonalityFn())
219  PerFn = dyn_cast<Function>(F.getPersonalityFn()->stripPointerCasts());
220  const MCSymbol *PersHandlerSym =
221  TLOF.getCFIPersonalitySymbol(PerFn, Asm->TM, MMI);
222 
223  // Do not emit a .seh_handler directives for cleanup funclets.
224  // FIXME: This means cleanup funclets cannot handle exceptions. Given that
225  // Clang doesn't produce EH constructs inside cleanup funclets and LLVM's
226  // inliner doesn't allow inlining them, this isn't a major problem in
227  // practice.
228  if (!CurrentFuncletEntry->isCleanupFuncletEntry())
229  Asm->OutStreamer->EmitWinEHHandler(PersHandlerSym, true, true);
230  }
231 }
232 
234  // No funclet to process? Great, we have nothing to do.
235  if (!CurrentFuncletEntry)
236  return;
237 
238  const MachineFunction *MF = Asm->MF;
239  if (shouldEmitMoves || shouldEmitPersonality) {
240  const Function &F = MF->getFunction();
242  if (F.hasPersonalityFn())
244 
245  // Emit an UNWIND_INFO struct describing the prologue.
246  Asm->OutStreamer->EmitWinEHHandlerData();
247 
248  if (Per == EHPersonality::MSVC_CXX && shouldEmitPersonality &&
249  !CurrentFuncletEntry->isCleanupFuncletEntry()) {
250  // If this is a C++ catch funclet (or the parent function),
251  // emit a reference to the LSDA for the parent function.
253  MCSymbol *FuncInfoXData = Asm->OutContext.getOrCreateSymbol(
254  Twine("$cppxdata$", FuncLinkageName));
255  Asm->OutStreamer->EmitValue(create32bitRef(FuncInfoXData), 4);
256  } else if (Per == EHPersonality::MSVC_Win64SEH && MF->hasEHFunclets() &&
257  !CurrentFuncletEntry->isEHFuncletEntry()) {
258  // If this is the parent function in Win64 SEH, emit the LSDA immediately
259  // following .seh_handlerdata.
260  emitCSpecificHandlerTable(MF);
261  }
262 
263  // Switch back to the funclet start .text section now that we are done
264  // writing to .xdata, and emit an .seh_endproc directive to mark the end of
265  // the function.
266  Asm->OutStreamer->SwitchSection(CurrentFuncletTextSection);
267  Asm->OutStreamer->EmitWinCFIEndProc();
268  }
269 
270  // Let's make sure we don't try to end the same funclet twice.
271  CurrentFuncletEntry = nullptr;
272 }
273 
274 const MCExpr *WinException::create32bitRef(const MCSymbol *Value) {
275  if (!Value)
277  return MCSymbolRefExpr::create(Value, useImageRel32
280  Asm->OutContext);
281 }
282 
283 const MCExpr *WinException::create32bitRef(const GlobalValue *GV) {
284  if (!GV)
286  return create32bitRef(Asm->getSymbol(GV));
287 }
288 
289 const MCExpr *WinException::getLabelPlusOne(const MCSymbol *Label) {
290  return MCBinaryExpr::createAdd(create32bitRef(Label),
292  Asm->OutContext);
293 }
294 
295 const MCExpr *WinException::getOffset(const MCSymbol *OffsetOf,
296  const MCSymbol *OffsetFrom) {
300 }
301 
302 const MCExpr *WinException::getOffsetPlusOne(const MCSymbol *OffsetOf,
303  const MCSymbol *OffsetFrom) {
304  return MCBinaryExpr::createAdd(getOffset(OffsetOf, OffsetFrom),
306  Asm->OutContext);
307 }
308 
309 int WinException::getFrameIndexOffset(int FrameIndex,
310  const WinEHFuncInfo &FuncInfo) {
312  unsigned UnusedReg;
313  if (Asm->MAI->usesWindowsCFI()) {
314  int Offset =
316  /*IgnoreSPUpdates*/ true);
317  assert(UnusedReg ==
318  Asm->MF->getSubtarget()
321  return Offset;
322  }
323 
324  // For 32-bit, offsets should be relative to the end of the EH registration
325  // node. For 64-bit, it's relative to SP at the end of the prologue.
326  assert(FuncInfo.EHRegNodeEndOffset != INT_MAX);
327  int Offset = TFI.getFrameIndexReference(*Asm->MF, FrameIndex, UnusedReg);
328  Offset += FuncInfo.EHRegNodeEndOffset;
329  return Offset;
330 }
331 
332 namespace {
333 
334 /// Top-level state used to represent unwind to caller
335 const int NullState = -1;
336 
337 struct InvokeStateChange {
338  /// EH Label immediately after the last invoke in the previous state, or
339  /// nullptr if the previous state was the null state.
340  const MCSymbol *PreviousEndLabel;
341 
342  /// EH label immediately before the first invoke in the new state, or nullptr
343  /// if the new state is the null state.
344  const MCSymbol *NewStartLabel;
345 
346  /// State of the invoke following NewStartLabel, or NullState to indicate
347  /// the presence of calls which may unwind to caller.
348  int NewState;
349 };
350 
351 /// Iterator that reports all the invoke state changes in a range of machine
352 /// basic blocks. Changes to the null state are reported whenever a call that
353 /// may unwind to caller is encountered. The MBB range is expected to be an
354 /// entire function or funclet, and the start and end of the range are treated
355 /// as being in the NullState even if there's not an unwind-to-caller call
356 /// before the first invoke or after the last one (i.e., the first state change
357 /// reported is the first change to something other than NullState, and a
358 /// change back to NullState is always reported at the end of iteration).
359 class InvokeStateChangeIterator {
360  InvokeStateChangeIterator(const WinEHFuncInfo &EHInfo,
364  int BaseState)
365  : EHInfo(EHInfo), MFI(MFI), MFE(MFE), MBBI(MBBI), BaseState(BaseState) {
366  LastStateChange.PreviousEndLabel = nullptr;
367  LastStateChange.NewStartLabel = nullptr;
368  LastStateChange.NewState = BaseState;
369  scan();
370  }
371 
372 public:
374  range(const WinEHFuncInfo &EHInfo, MachineFunction::const_iterator Begin,
375  MachineFunction::const_iterator End, int BaseState = NullState) {
376  // Reject empty ranges to simplify bookkeeping by ensuring that we can get
377  // the end of the last block.
378  assert(Begin != End);
379  auto BlockBegin = Begin->begin();
380  auto BlockEnd = std::prev(End)->end();
381  return make_range(
382  InvokeStateChangeIterator(EHInfo, Begin, End, BlockBegin, BaseState),
383  InvokeStateChangeIterator(EHInfo, End, End, BlockEnd, BaseState));
384  }
385 
386  // Iterator methods.
387  bool operator==(const InvokeStateChangeIterator &O) const {
388  assert(BaseState == O.BaseState);
389  // Must be visiting same block.
390  if (MFI != O.MFI)
391  return false;
392  // Must be visiting same isntr.
393  if (MBBI != O.MBBI)
394  return false;
395  // At end of block/instr iteration, we can still have two distinct states:
396  // one to report the final EndLabel, and another indicating the end of the
397  // state change iteration. Check for CurrentEndLabel equality to
398  // distinguish these.
399  return CurrentEndLabel == O.CurrentEndLabel;
400  }
401 
402  bool operator!=(const InvokeStateChangeIterator &O) const {
403  return !operator==(O);
404  }
405  InvokeStateChange &operator*() { return LastStateChange; }
406  InvokeStateChange *operator->() { return &LastStateChange; }
407  InvokeStateChangeIterator &operator++() { return scan(); }
408 
409 private:
410  InvokeStateChangeIterator &scan();
411 
412  const WinEHFuncInfo &EHInfo;
413  const MCSymbol *CurrentEndLabel = nullptr;
417  InvokeStateChange LastStateChange;
418  bool VisitingInvoke = false;
419  int BaseState;
420 };
421 
422 } // end anonymous namespace
423 
424 InvokeStateChangeIterator &InvokeStateChangeIterator::scan() {
425  bool IsNewBlock = false;
426  for (; MFI != MFE; ++MFI, IsNewBlock = true) {
427  if (IsNewBlock)
428  MBBI = MFI->begin();
429  for (auto MBBE = MFI->end(); MBBI != MBBE; ++MBBI) {
430  const MachineInstr &MI = *MBBI;
431  if (!VisitingInvoke && LastStateChange.NewState != BaseState &&
433  // Indicate a change of state to the null state. We don't have
434  // start/end EH labels handy but the caller won't expect them for
435  // null state regions.
436  LastStateChange.PreviousEndLabel = CurrentEndLabel;
437  LastStateChange.NewStartLabel = nullptr;
438  LastStateChange.NewState = BaseState;
439  CurrentEndLabel = nullptr;
440  // Don't re-visit this instr on the next scan
441  ++MBBI;
442  return *this;
443  }
444 
445  // All other state changes are at EH labels before/after invokes.
446  if (!MI.isEHLabel())
447  continue;
448  MCSymbol *Label = MI.getOperand(0).getMCSymbol();
449  if (Label == CurrentEndLabel) {
450  VisitingInvoke = false;
451  continue;
452  }
453  auto InvokeMapIter = EHInfo.LabelToStateMap.find(Label);
454  // Ignore EH labels that aren't the ones inserted before an invoke
455  if (InvokeMapIter == EHInfo.LabelToStateMap.end())
456  continue;
457  auto &StateAndEnd = InvokeMapIter->second;
458  int NewState = StateAndEnd.first;
459  // Keep track of the fact that we're between EH start/end labels so
460  // we know not to treat the inoke we'll see as unwinding to caller.
461  VisitingInvoke = true;
462  if (NewState == LastStateChange.NewState) {
463  // The state isn't actually changing here. Record the new end and
464  // keep going.
465  CurrentEndLabel = StateAndEnd.second;
466  continue;
467  }
468  // Found a state change to report
469  LastStateChange.PreviousEndLabel = CurrentEndLabel;
470  LastStateChange.NewStartLabel = Label;
471  LastStateChange.NewState = NewState;
472  // Start keeping track of the new current end
473  CurrentEndLabel = StateAndEnd.second;
474  // Don't re-visit this instr on the next scan
475  ++MBBI;
476  return *this;
477  }
478  }
479  // Iteration hit the end of the block range.
480  if (LastStateChange.NewState != BaseState) {
481  // Report the end of the last new state
482  LastStateChange.PreviousEndLabel = CurrentEndLabel;
483  LastStateChange.NewStartLabel = nullptr;
484  LastStateChange.NewState = BaseState;
485  // Leave CurrentEndLabel non-null to distinguish this state from end.
486  assert(CurrentEndLabel != nullptr);
487  return *this;
488  }
489  // We've reported all state changes and hit the end state.
490  CurrentEndLabel = nullptr;
491  return *this;
492 }
493 
494 /// Emit the language-specific data that __C_specific_handler expects. This
495 /// handler lives in the x64 Microsoft C runtime and allows catching or cleaning
496 /// up after faults with __try, __except, and __finally. The typeinfo values
497 /// are not really RTTI data, but pointers to filter functions that return an
498 /// integer (1, 0, or -1) indicating how to handle the exception. For __finally
499 /// blocks and other cleanups, the landing pad label is zero, and the filter
500 /// function is actually a cleanup handler with the same prototype. A catch-all
501 /// entry is modeled with a null filter function field and a non-zero landing
502 /// pad label.
503 ///
504 /// Possible filter function return values:
505 /// EXCEPTION_EXECUTE_HANDLER (1):
506 /// Jump to the landing pad label after cleanups.
507 /// EXCEPTION_CONTINUE_SEARCH (0):
508 /// Continue searching this table or continue unwinding.
509 /// EXCEPTION_CONTINUE_EXECUTION (-1):
510 /// Resume execution at the trapping PC.
511 ///
512 /// Inferred table structure:
513 /// struct Table {
514 /// int NumEntries;
515 /// struct Entry {
516 /// imagerel32 LabelStart;
517 /// imagerel32 LabelEnd;
518 /// imagerel32 FilterOrFinally; // One means catch-all.
519 /// imagerel32 LabelLPad; // Zero means __finally.
520 /// } Entries[NumEntries];
521 /// };
522 void WinException::emitCSpecificHandlerTable(const MachineFunction *MF) {
523  auto &OS = *Asm->OutStreamer;
524  MCContext &Ctx = Asm->OutContext;
525  const WinEHFuncInfo &FuncInfo = *MF->getWinEHFuncInfo();
526 
527  bool VerboseAsm = OS.isVerboseAsm();
528  auto AddComment = [&](const Twine &Comment) {
529  if (VerboseAsm)
530  OS.AddComment(Comment);
531  };
532 
533  // Emit a label assignment with the SEH frame offset so we can use it for
534  // llvm.x86.seh.recoverfp.
535  StringRef FLinkageName =
537  MCSymbol *ParentFrameOffset =
538  Ctx.getOrCreateParentFrameOffsetSymbol(FLinkageName);
539  const MCExpr *MCOffset =
541  Asm->OutStreamer->EmitAssignment(ParentFrameOffset, MCOffset);
542 
543  // Use the assembler to compute the number of table entries through label
544  // difference and division.
545  MCSymbol *TableBegin =
546  Ctx.createTempSymbol("lsda_begin", /*AlwaysAddSuffix=*/true);
547  MCSymbol *TableEnd =
548  Ctx.createTempSymbol("lsda_end", /*AlwaysAddSuffix=*/true);
549  const MCExpr *LabelDiff = getOffset(TableEnd, TableBegin);
550  const MCExpr *EntrySize = MCConstantExpr::create(16, Ctx);
551  const MCExpr *EntryCount = MCBinaryExpr::createDiv(LabelDiff, EntrySize, Ctx);
552  AddComment("Number of call sites");
553  OS.EmitValue(EntryCount, 4);
554 
555  OS.EmitLabel(TableBegin);
556 
557  // Iterate over all the invoke try ranges. Unlike MSVC, LLVM currently only
558  // models exceptions from invokes. LLVM also allows arbitrary reordering of
559  // the code, so our tables end up looking a bit different. Rather than
560  // trying to match MSVC's tables exactly, we emit a denormalized table. For
561  // each range of invokes in the same state, we emit table entries for all
562  // the actions that would be taken in that state. This means our tables are
563  // slightly bigger, which is OK.
564  const MCSymbol *LastStartLabel = nullptr;
565  int LastEHState = -1;
566  // Break out before we enter into a finally funclet.
567  // FIXME: We need to emit separate EH tables for cleanups.
569  MachineFunction::const_iterator Stop = std::next(MF->begin());
570  while (Stop != End && !Stop->isEHFuncletEntry())
571  ++Stop;
572  for (const auto &StateChange :
573  InvokeStateChangeIterator::range(FuncInfo, MF->begin(), Stop)) {
574  // Emit all the actions for the state we just transitioned out of
575  // if it was not the null state
576  if (LastEHState != -1)
577  emitSEHActionsForRange(FuncInfo, LastStartLabel,
578  StateChange.PreviousEndLabel, LastEHState);
579  LastStartLabel = StateChange.NewStartLabel;
580  LastEHState = StateChange.NewState;
581  }
582 
583  OS.EmitLabel(TableEnd);
584 }
585 
586 void WinException::emitSEHActionsForRange(const WinEHFuncInfo &FuncInfo,
587  const MCSymbol *BeginLabel,
588  const MCSymbol *EndLabel, int State) {
589  auto &OS = *Asm->OutStreamer;
590  MCContext &Ctx = Asm->OutContext;
591 
592  bool VerboseAsm = OS.isVerboseAsm();
593  auto AddComment = [&](const Twine &Comment) {
594  if (VerboseAsm)
595  OS.AddComment(Comment);
596  };
597 
598  assert(BeginLabel && EndLabel);
599  while (State != -1) {
600  const SEHUnwindMapEntry &UME = FuncInfo.SEHUnwindMap[State];
601  const MCExpr *FilterOrFinally;
602  const MCExpr *ExceptOrNull;
603  auto *Handler = UME.Handler.get<MachineBasicBlock *>();
604  if (UME.IsFinally) {
605  FilterOrFinally = create32bitRef(getMCSymbolForMBB(Asm, Handler));
606  ExceptOrNull = MCConstantExpr::create(0, Ctx);
607  } else {
608  // For an except, the filter can be 1 (catch-all) or a function
609  // label.
610  FilterOrFinally = UME.Filter ? create32bitRef(UME.Filter)
611  : MCConstantExpr::create(1, Ctx);
612  ExceptOrNull = create32bitRef(Handler->getSymbol());
613  }
614 
615  AddComment("LabelStart");
616  OS.EmitValue(getLabelPlusOne(BeginLabel), 4);
617  AddComment("LabelEnd");
618  OS.EmitValue(getLabelPlusOne(EndLabel), 4);
619  AddComment(UME.IsFinally ? "FinallyFunclet" : UME.Filter ? "FilterFunction"
620  : "CatchAll");
621  OS.EmitValue(FilterOrFinally, 4);
622  AddComment(UME.IsFinally ? "Null" : "ExceptionHandler");
623  OS.EmitValue(ExceptOrNull, 4);
624 
625  assert(UME.ToState < State && "states should decrease");
626  State = UME.ToState;
627  }
628 }
629 
630 void WinException::emitCXXFrameHandler3Table(const MachineFunction *MF) {
631  const Function &F = MF->getFunction();
632  auto &OS = *Asm->OutStreamer;
633  const WinEHFuncInfo &FuncInfo = *MF->getWinEHFuncInfo();
634 
636 
638  MCSymbol *FuncInfoXData = nullptr;
639  if (shouldEmitPersonality) {
640  // If we're 64-bit, emit a pointer to the C++ EH data, and build a map from
641  // IPs to state numbers.
642  FuncInfoXData =
643  Asm->OutContext.getOrCreateSymbol(Twine("$cppxdata$", FuncLinkageName));
644  computeIP2StateTable(MF, FuncInfo, IPToStateTable);
645  } else {
646  FuncInfoXData = Asm->OutContext.getOrCreateLSDASymbol(FuncLinkageName);
647  }
648 
649  int UnwindHelpOffset = 0;
650  if (Asm->MAI->usesWindowsCFI())
651  UnwindHelpOffset =
652  getFrameIndexOffset(FuncInfo.UnwindHelpFrameIdx, FuncInfo);
653 
654  MCSymbol *UnwindMapXData = nullptr;
655  MCSymbol *TryBlockMapXData = nullptr;
656  MCSymbol *IPToStateXData = nullptr;
657  if (!FuncInfo.CxxUnwindMap.empty())
658  UnwindMapXData = Asm->OutContext.getOrCreateSymbol(
659  Twine("$stateUnwindMap$", FuncLinkageName));
660  if (!FuncInfo.TryBlockMap.empty())
661  TryBlockMapXData =
662  Asm->OutContext.getOrCreateSymbol(Twine("$tryMap$", FuncLinkageName));
663  if (!IPToStateTable.empty())
664  IPToStateXData =
665  Asm->OutContext.getOrCreateSymbol(Twine("$ip2state$", FuncLinkageName));
666 
667  bool VerboseAsm = OS.isVerboseAsm();
668  auto AddComment = [&](const Twine &Comment) {
669  if (VerboseAsm)
670  OS.AddComment(Comment);
671  };
672 
673  // FuncInfo {
674  // uint32_t MagicNumber
675  // int32_t MaxState;
676  // UnwindMapEntry *UnwindMap;
677  // uint32_t NumTryBlocks;
678  // TryBlockMapEntry *TryBlockMap;
679  // uint32_t IPMapEntries; // always 0 for x86
680  // IPToStateMapEntry *IPToStateMap; // always 0 for x86
681  // uint32_t UnwindHelp; // non-x86 only
682  // ESTypeList *ESTypeList;
683  // int32_t EHFlags;
684  // }
685  // EHFlags & 1 -> Synchronous exceptions only, no async exceptions.
686  // EHFlags & 2 -> ???
687  // EHFlags & 4 -> The function is noexcept(true), unwinding can't continue.
688  OS.EmitValueToAlignment(4);
689  OS.EmitLabel(FuncInfoXData);
690 
691  AddComment("MagicNumber");
692  OS.EmitIntValue(0x19930522, 4);
693 
694  AddComment("MaxState");
695  OS.EmitIntValue(FuncInfo.CxxUnwindMap.size(), 4);
696 
697  AddComment("UnwindMap");
698  OS.EmitValue(create32bitRef(UnwindMapXData), 4);
699 
700  AddComment("NumTryBlocks");
701  OS.EmitIntValue(FuncInfo.TryBlockMap.size(), 4);
702 
703  AddComment("TryBlockMap");
704  OS.EmitValue(create32bitRef(TryBlockMapXData), 4);
705 
706  AddComment("IPMapEntries");
707  OS.EmitIntValue(IPToStateTable.size(), 4);
708 
709  AddComment("IPToStateXData");
710  OS.EmitValue(create32bitRef(IPToStateXData), 4);
711 
712  if (Asm->MAI->usesWindowsCFI()) {
713  AddComment("UnwindHelp");
714  OS.EmitIntValue(UnwindHelpOffset, 4);
715  }
716 
717  AddComment("ESTypeList");
718  OS.EmitIntValue(0, 4);
719 
720  AddComment("EHFlags");
721  OS.EmitIntValue(1, 4);
722 
723  // UnwindMapEntry {
724  // int32_t ToState;
725  // void (*Action)();
726  // };
727  if (UnwindMapXData) {
728  OS.EmitLabel(UnwindMapXData);
729  for (const CxxUnwindMapEntry &UME : FuncInfo.CxxUnwindMap) {
730  MCSymbol *CleanupSym =
732  AddComment("ToState");
733  OS.EmitIntValue(UME.ToState, 4);
734 
735  AddComment("Action");
736  OS.EmitValue(create32bitRef(CleanupSym), 4);
737  }
738  }
739 
740  // TryBlockMap {
741  // int32_t TryLow;
742  // int32_t TryHigh;
743  // int32_t CatchHigh;
744  // int32_t NumCatches;
745  // HandlerType *HandlerArray;
746  // };
747  if (TryBlockMapXData) {
748  OS.EmitLabel(TryBlockMapXData);
749  SmallVector<MCSymbol *, 1> HandlerMaps;
750  for (size_t I = 0, E = FuncInfo.TryBlockMap.size(); I != E; ++I) {
751  const WinEHTryBlockMapEntry &TBME = FuncInfo.TryBlockMap[I];
752 
753  MCSymbol *HandlerMapXData = nullptr;
754  if (!TBME.HandlerArray.empty())
755  HandlerMapXData =
756  Asm->OutContext.getOrCreateSymbol(Twine("$handlerMap$")
757  .concat(Twine(I))
758  .concat("$")
759  .concat(FuncLinkageName));
760  HandlerMaps.push_back(HandlerMapXData);
761 
762  // TBMEs should form intervals.
763  assert(0 <= TBME.TryLow && "bad trymap interval");
764  assert(TBME.TryLow <= TBME.TryHigh && "bad trymap interval");
765  assert(TBME.TryHigh < TBME.CatchHigh && "bad trymap interval");
766  assert(TBME.CatchHigh < int(FuncInfo.CxxUnwindMap.size()) &&
767  "bad trymap interval");
768 
769  AddComment("TryLow");
770  OS.EmitIntValue(TBME.TryLow, 4);
771 
772  AddComment("TryHigh");
773  OS.EmitIntValue(TBME.TryHigh, 4);
774 
775  AddComment("CatchHigh");
776  OS.EmitIntValue(TBME.CatchHigh, 4);
777 
778  AddComment("NumCatches");
779  OS.EmitIntValue(TBME.HandlerArray.size(), 4);
780 
781  AddComment("HandlerArray");
782  OS.EmitValue(create32bitRef(HandlerMapXData), 4);
783  }
784 
785  // All funclets use the same parent frame offset currently.
786  unsigned ParentFrameOffset = 0;
787  if (shouldEmitPersonality) {
789  ParentFrameOffset = TFI->getWinEHParentFrameOffset(*MF);
790  }
791 
792  for (size_t I = 0, E = FuncInfo.TryBlockMap.size(); I != E; ++I) {
793  const WinEHTryBlockMapEntry &TBME = FuncInfo.TryBlockMap[I];
794  MCSymbol *HandlerMapXData = HandlerMaps[I];
795  if (!HandlerMapXData)
796  continue;
797  // HandlerType {
798  // int32_t Adjectives;
799  // TypeDescriptor *Type;
800  // int32_t CatchObjOffset;
801  // void (*Handler)();
802  // int32_t ParentFrameOffset; // x64 only
803  // };
804  OS.EmitLabel(HandlerMapXData);
805  for (const WinEHHandlerType &HT : TBME.HandlerArray) {
806  // Get the frame escape label with the offset of the catch object. If
807  // the index is INT_MAX, then there is no catch object, and we should
808  // emit an offset of zero, indicating that no copy will occur.
809  const MCExpr *FrameAllocOffsetRef = nullptr;
810  if (HT.CatchObj.FrameIndex != INT_MAX) {
811  int Offset = getFrameIndexOffset(HT.CatchObj.FrameIndex, FuncInfo);
812  assert(Offset != 0 && "Illegal offset for catch object!");
813  FrameAllocOffsetRef = MCConstantExpr::create(Offset, Asm->OutContext);
814  } else {
815  FrameAllocOffsetRef = MCConstantExpr::create(0, Asm->OutContext);
816  }
817 
818  MCSymbol *HandlerSym =
820 
821  AddComment("Adjectives");
822  OS.EmitIntValue(HT.Adjectives, 4);
823 
824  AddComment("Type");
825  OS.EmitValue(create32bitRef(HT.TypeDescriptor), 4);
826 
827  AddComment("CatchObjOffset");
828  OS.EmitValue(FrameAllocOffsetRef, 4);
829 
830  AddComment("Handler");
831  OS.EmitValue(create32bitRef(HandlerSym), 4);
832 
833  if (shouldEmitPersonality) {
834  AddComment("ParentFrameOffset");
835  OS.EmitIntValue(ParentFrameOffset, 4);
836  }
837  }
838  }
839  }
840 
841  // IPToStateMapEntry {
842  // void *IP;
843  // int32_t State;
844  // };
845  if (IPToStateXData) {
846  OS.EmitLabel(IPToStateXData);
847  for (auto &IPStatePair : IPToStateTable) {
848  AddComment("IP");
849  OS.EmitValue(IPStatePair.first, 4);
850  AddComment("ToState");
851  OS.EmitIntValue(IPStatePair.second, 4);
852  }
853  }
854 }
855 
856 void WinException::computeIP2StateTable(
857  const MachineFunction *MF, const WinEHFuncInfo &FuncInfo,
858  SmallVectorImpl<std::pair<const MCExpr *, int>> &IPToStateTable) {
859 
860  for (MachineFunction::const_iterator FuncletStart = MF->begin(),
861  FuncletEnd = MF->begin(),
862  End = MF->end();
863  FuncletStart != End; FuncletStart = FuncletEnd) {
864  // Find the end of the funclet
865  while (++FuncletEnd != End) {
866  if (FuncletEnd->isEHFuncletEntry()) {
867  break;
868  }
869  }
870 
871  // Don't emit ip2state entries for cleanup funclets. Any interesting
872  // exceptional actions in cleanups must be handled in a separate IR
873  // function.
874  if (FuncletStart->isCleanupFuncletEntry())
875  continue;
876 
877  MCSymbol *StartLabel;
878  int BaseState;
879  if (FuncletStart == MF->begin()) {
880  BaseState = NullState;
881  StartLabel = Asm->getFunctionBegin();
882  } else {
883  auto *FuncletPad =
884  cast<FuncletPadInst>(FuncletStart->getBasicBlock()->getFirstNonPHI());
885  assert(FuncInfo.FuncletBaseStateMap.count(FuncletPad) != 0);
886  BaseState = FuncInfo.FuncletBaseStateMap.find(FuncletPad)->second;
887  StartLabel = getMCSymbolForMBB(Asm, &*FuncletStart);
888  }
889  assert(StartLabel && "need local function start label");
890  IPToStateTable.push_back(
891  std::make_pair(create32bitRef(StartLabel), BaseState));
892 
893  for (const auto &StateChange : InvokeStateChangeIterator::range(
894  FuncInfo, FuncletStart, FuncletEnd, BaseState)) {
895  // Compute the label to report as the start of this entry; use the EH
896  // start label for the invoke if we have one, otherwise (this is a call
897  // which may unwind to our caller and does not have an EH start label, so)
898  // use the previous end label.
899  const MCSymbol *ChangeLabel = StateChange.NewStartLabel;
900  if (!ChangeLabel)
901  ChangeLabel = StateChange.PreviousEndLabel;
902  // Emit an entry indicating that PCs after 'Label' have this EH state.
903  IPToStateTable.push_back(
904  std::make_pair(getLabelPlusOne(ChangeLabel), StateChange.NewState));
905  // FIXME: assert that NewState is between CatchLow and CatchHigh.
906  }
907  }
908 }
909 
910 void WinException::emitEHRegistrationOffsetLabel(const WinEHFuncInfo &FuncInfo,
911  StringRef FLinkageName) {
912  // Outlined helpers called by the EH runtime need to know the offset of the EH
913  // registration in order to recover the parent frame pointer. Now that we know
914  // we've code generated the parent, we can emit the label assignment that
915  // those helpers use to get the offset of the registration node.
916 
917  // Compute the parent frame offset. The EHRegNodeFrameIndex will be invalid if
918  // after optimization all the invokes were eliminated. We still need to emit
919  // the parent frame offset label, but it should be garbage and should never be
920  // used.
921  int64_t Offset = 0;
922  int FI = FuncInfo.EHRegNodeFrameIndex;
923  if (FI != INT_MAX) {
925  unsigned UnusedReg;
926  Offset = TFI->getFrameIndexReference(*Asm->MF, FI, UnusedReg);
927  }
928 
929  MCContext &Ctx = Asm->OutContext;
930  MCSymbol *ParentFrameOffset =
931  Ctx.getOrCreateParentFrameOffsetSymbol(FLinkageName);
932  Asm->OutStreamer->EmitAssignment(ParentFrameOffset,
933  MCConstantExpr::create(Offset, Ctx));
934 }
935 
936 /// Emit the language-specific data that _except_handler3 and 4 expect. This is
937 /// functionally equivalent to the __C_specific_handler table, except it is
938 /// indexed by state number instead of IP.
939 void WinException::emitExceptHandlerTable(const MachineFunction *MF) {
940  MCStreamer &OS = *Asm->OutStreamer;
941  const Function &F = MF->getFunction();
943 
944  bool VerboseAsm = OS.isVerboseAsm();
945  auto AddComment = [&](const Twine &Comment) {
946  if (VerboseAsm)
947  OS.AddComment(Comment);
948  };
949 
950  const WinEHFuncInfo &FuncInfo = *MF->getWinEHFuncInfo();
951  emitEHRegistrationOffsetLabel(FuncInfo, FLinkageName);
952 
953  // Emit the __ehtable label that we use for llvm.x86.seh.lsda.
954  MCSymbol *LSDALabel = Asm->OutContext.getOrCreateLSDASymbol(FLinkageName);
955  OS.EmitValueToAlignment(4);
956  OS.EmitLabel(LSDALabel);
957 
958  const Function *Per =
960  StringRef PerName = Per->getName();
961  int BaseState = -1;
962  if (PerName == "_except_handler4") {
963  // The LSDA for _except_handler4 starts with this struct, followed by the
964  // scope table:
965  //
966  // struct EH4ScopeTable {
967  // int32_t GSCookieOffset;
968  // int32_t GSCookieXOROffset;
969  // int32_t EHCookieOffset;
970  // int32_t EHCookieXOROffset;
971  // ScopeTableEntry ScopeRecord[];
972  // };
973  //
974  // Offsets are %ebp relative.
975  //
976  // The GS cookie is present only if the function needs stack protection.
977  // GSCookieOffset = -2 means that GS cookie is not used.
978  //
979  // The EH cookie is always present.
980  //
981  // Check is done the following way:
982  // (ebp+CookieXOROffset) ^ [ebp+CookieOffset] == _security_cookie
983 
984  // Retrieve the Guard Stack slot.
985  int GSCookieOffset = -2;
986  const MachineFrameInfo &MFI = MF->getFrameInfo();
987  if (MFI.hasStackProtectorIndex()) {
988  unsigned UnusedReg;
990  int SSPIdx = MFI.getStackProtectorIndex();
991  GSCookieOffset = TFI->getFrameIndexReference(*MF, SSPIdx, UnusedReg);
992  }
993 
994  // Retrieve the EH Guard slot.
995  // TODO(etienneb): Get rid of this value and change it for and assertion.
996  int EHCookieOffset = 9999;
997  if (FuncInfo.EHGuardFrameIndex != INT_MAX) {
998  unsigned UnusedReg;
1000  int EHGuardIdx = FuncInfo.EHGuardFrameIndex;
1001  EHCookieOffset = TFI->getFrameIndexReference(*MF, EHGuardIdx, UnusedReg);
1002  }
1003 
1004  AddComment("GSCookieOffset");
1005  OS.EmitIntValue(GSCookieOffset, 4);
1006  AddComment("GSCookieXOROffset");
1007  OS.EmitIntValue(0, 4);
1008  AddComment("EHCookieOffset");
1009  OS.EmitIntValue(EHCookieOffset, 4);
1010  AddComment("EHCookieXOROffset");
1011  OS.EmitIntValue(0, 4);
1012  BaseState = -2;
1013  }
1014 
1015  assert(!FuncInfo.SEHUnwindMap.empty());
1016  for (const SEHUnwindMapEntry &UME : FuncInfo.SEHUnwindMap) {
1017  auto *Handler = UME.Handler.get<MachineBasicBlock *>();
1018  const MCSymbol *ExceptOrFinally =
1019  UME.IsFinally ? getMCSymbolForMBB(Asm, Handler) : Handler->getSymbol();
1020  // -1 is usually the base state for "unwind to caller", but for
1021  // _except_handler4 it's -2. Do that replacement here if necessary.
1022  int ToState = UME.ToState == -1 ? BaseState : UME.ToState;
1023  AddComment("ToState");
1024  OS.EmitIntValue(ToState, 4);
1025  AddComment(UME.IsFinally ? "Null" : "FilterFunction");
1026  OS.EmitValue(create32bitRef(UME.Filter), 4);
1027  AddComment(UME.IsFinally ? "FinallyFunclet" : "ExceptionHandler");
1028  OS.EmitValue(create32bitRef(ExceptOrFinally), 4);
1029  }
1030 }
1031 
1032 static int getTryRank(const WinEHFuncInfo &FuncInfo, int State) {
1033  int Rank = 0;
1034  while (State != -1) {
1035  ++Rank;
1036  State = FuncInfo.ClrEHUnwindMap[State].TryParentState;
1037  }
1038  return Rank;
1039 }
1040 
1041 static int getTryAncestor(const WinEHFuncInfo &FuncInfo, int Left, int Right) {
1042  int LeftRank = getTryRank(FuncInfo, Left);
1043  int RightRank = getTryRank(FuncInfo, Right);
1044 
1045  while (LeftRank < RightRank) {
1046  Right = FuncInfo.ClrEHUnwindMap[Right].TryParentState;
1047  --RightRank;
1048  }
1049 
1050  while (RightRank < LeftRank) {
1051  Left = FuncInfo.ClrEHUnwindMap[Left].TryParentState;
1052  --LeftRank;
1053  }
1054 
1055  while (Left != Right) {
1056  Left = FuncInfo.ClrEHUnwindMap[Left].TryParentState;
1057  Right = FuncInfo.ClrEHUnwindMap[Right].TryParentState;
1058  }
1059 
1060  return Left;
1061 }
1062 
1063 void WinException::emitCLRExceptionTable(const MachineFunction *MF) {
1064  // CLR EH "states" are really just IDs that identify handlers/funclets;
1065  // states, handlers, and funclets all have 1:1 mappings between them, and a
1066  // handler/funclet's "state" is its index in the ClrEHUnwindMap.
1067  MCStreamer &OS = *Asm->OutStreamer;
1068  const WinEHFuncInfo &FuncInfo = *MF->getWinEHFuncInfo();
1069  MCSymbol *FuncBeginSym = Asm->getFunctionBegin();
1070  MCSymbol *FuncEndSym = Asm->getFunctionEnd();
1071 
1072  // A ClrClause describes a protected region.
1073  struct ClrClause {
1074  const MCSymbol *StartLabel; // Start of protected region
1075  const MCSymbol *EndLabel; // End of protected region
1076  int State; // Index of handler protecting the protected region
1077  int EnclosingState; // Index of funclet enclosing the protected region
1078  };
1079  SmallVector<ClrClause, 8> Clauses;
1080 
1081  // Build a map from handler MBBs to their corresponding states (i.e. their
1082  // indices in the ClrEHUnwindMap).
1083  int NumStates = FuncInfo.ClrEHUnwindMap.size();
1084  assert(NumStates > 0 && "Don't need exception table!");
1086  for (int State = 0; State < NumStates; ++State) {
1087  MachineBasicBlock *HandlerBlock =
1088  FuncInfo.ClrEHUnwindMap[State].Handler.get<MachineBasicBlock *>();
1089  HandlerStates[HandlerBlock] = State;
1090  // Use this loop through all handlers to verify our assumption (used in
1091  // the MinEnclosingState computation) that enclosing funclets have lower
1092  // state numbers than their enclosed funclets.
1093  assert(FuncInfo.ClrEHUnwindMap[State].HandlerParentState < State &&
1094  "ill-formed state numbering");
1095  }
1096  // Map the main function to the NullState.
1097  HandlerStates[&MF->front()] = NullState;
1098 
1099  // Write out a sentinel indicating the end of the standard (Windows) xdata
1100  // and the start of the additional (CLR) info.
1101  OS.EmitIntValue(0xffffffff, 4);
1102  // Write out the number of funclets
1103  OS.EmitIntValue(NumStates, 4);
1104 
1105  // Walk the machine blocks/instrs, computing and emitting a few things:
1106  // 1. Emit a list of the offsets to each handler entry, in lexical order.
1107  // 2. Compute a map (EndSymbolMap) from each funclet to the symbol at its end.
1108  // 3. Compute the list of ClrClauses, in the required order (inner before
1109  // outer, earlier before later; the order by which a forward scan with
1110  // early termination will find the innermost enclosing clause covering
1111  // a given address).
1112  // 4. A map (MinClauseMap) from each handler index to the index of the
1113  // outermost funclet/function which contains a try clause targeting the
1114  // key handler. This will be used to determine IsDuplicate-ness when
1115  // emitting ClrClauses. The NullState value is used to indicate that the
1116  // top-level function contains a try clause targeting the key handler.
1117  // HandlerStack is a stack of (PendingStartLabel, PendingState) pairs for
1118  // try regions we entered before entering the PendingState try but which
1119  // we haven't yet exited.
1121  // EndSymbolMap and MinClauseMap are maps described above.
1122  std::unique_ptr<MCSymbol *[]> EndSymbolMap(new MCSymbol *[NumStates]);
1123  SmallVector<int, 4> MinClauseMap((size_t)NumStates, NumStates);
1124 
1125  // Visit the root function and each funclet.
1126  for (MachineFunction::const_iterator FuncletStart = MF->begin(),
1127  FuncletEnd = MF->begin(),
1128  End = MF->end();
1129  FuncletStart != End; FuncletStart = FuncletEnd) {
1130  int FuncletState = HandlerStates[&*FuncletStart];
1131  // Find the end of the funclet
1132  MCSymbol *EndSymbol = FuncEndSym;
1133  while (++FuncletEnd != End) {
1134  if (FuncletEnd->isEHFuncletEntry()) {
1135  EndSymbol = getMCSymbolForMBB(Asm, &*FuncletEnd);
1136  break;
1137  }
1138  }
1139  // Emit the function/funclet end and, if this is a funclet (and not the
1140  // root function), record it in the EndSymbolMap.
1141  OS.EmitValue(getOffset(EndSymbol, FuncBeginSym), 4);
1142  if (FuncletState != NullState) {
1143  // Record the end of the handler.
1144  EndSymbolMap[FuncletState] = EndSymbol;
1145  }
1146 
1147  // Walk the state changes in this function/funclet and compute its clauses.
1148  // Funclets always start in the null state.
1149  const MCSymbol *CurrentStartLabel = nullptr;
1150  int CurrentState = NullState;
1151  assert(HandlerStack.empty());
1152  for (const auto &StateChange :
1153  InvokeStateChangeIterator::range(FuncInfo, FuncletStart, FuncletEnd)) {
1154  // Close any try regions we're not still under
1155  int StillPendingState =
1156  getTryAncestor(FuncInfo, CurrentState, StateChange.NewState);
1157  while (CurrentState != StillPendingState) {
1158  assert(CurrentState != NullState &&
1159  "Failed to find still-pending state!");
1160  // Close the pending clause
1161  Clauses.push_back({CurrentStartLabel, StateChange.PreviousEndLabel,
1162  CurrentState, FuncletState});
1163  // Now the next-outer try region is current
1164  CurrentState = FuncInfo.ClrEHUnwindMap[CurrentState].TryParentState;
1165  // Pop the new start label from the handler stack if we've exited all
1166  // inner try regions of the corresponding try region.
1167  if (HandlerStack.back().second == CurrentState)
1168  CurrentStartLabel = HandlerStack.pop_back_val().first;
1169  }
1170 
1171  if (StateChange.NewState != CurrentState) {
1172  // For each clause we're starting, update the MinClauseMap so we can
1173  // know which is the topmost funclet containing a clause targeting
1174  // it.
1175  for (int EnteredState = StateChange.NewState;
1176  EnteredState != CurrentState;
1177  EnteredState =
1178  FuncInfo.ClrEHUnwindMap[EnteredState].TryParentState) {
1179  int &MinEnclosingState = MinClauseMap[EnteredState];
1180  if (FuncletState < MinEnclosingState)
1181  MinEnclosingState = FuncletState;
1182  }
1183  // Save the previous current start/label on the stack and update to
1184  // the newly-current start/state.
1185  HandlerStack.emplace_back(CurrentStartLabel, CurrentState);
1186  CurrentStartLabel = StateChange.NewStartLabel;
1187  CurrentState = StateChange.NewState;
1188  }
1189  }
1190  assert(HandlerStack.empty());
1191  }
1192 
1193  // Now emit the clause info, starting with the number of clauses.
1194  OS.EmitIntValue(Clauses.size(), 4);
1195  for (ClrClause &Clause : Clauses) {
1196  // Emit a CORINFO_EH_CLAUSE :
1197  /*
1198  struct CORINFO_EH_CLAUSE
1199  {
1200  CORINFO_EH_CLAUSE_FLAGS Flags; // actually a CorExceptionFlag
1201  DWORD TryOffset;
1202  DWORD TryLength; // actually TryEndOffset
1203  DWORD HandlerOffset;
1204  DWORD HandlerLength; // actually HandlerEndOffset
1205  union
1206  {
1207  DWORD ClassToken; // use for catch clauses
1208  DWORD FilterOffset; // use for filter clauses
1209  };
1210  };
1211 
1212  enum CORINFO_EH_CLAUSE_FLAGS
1213  {
1214  CORINFO_EH_CLAUSE_NONE = 0,
1215  CORINFO_EH_CLAUSE_FILTER = 0x0001, // This clause is for a filter
1216  CORINFO_EH_CLAUSE_FINALLY = 0x0002, // This clause is a finally clause
1217  CORINFO_EH_CLAUSE_FAULT = 0x0004, // This clause is a fault clause
1218  };
1219  typedef enum CorExceptionFlag
1220  {
1221  COR_ILEXCEPTION_CLAUSE_NONE,
1222  COR_ILEXCEPTION_CLAUSE_FILTER = 0x0001, // This is a filter clause
1223  COR_ILEXCEPTION_CLAUSE_FINALLY = 0x0002, // This is a finally clause
1224  COR_ILEXCEPTION_CLAUSE_FAULT = 0x0004, // This is a fault clause
1225  COR_ILEXCEPTION_CLAUSE_DUPLICATED = 0x0008, // duplicated clause. This
1226  // clause was duplicated
1227  // to a funclet which was
1228  // pulled out of line
1229  } CorExceptionFlag;
1230  */
1231  // Add 1 to the start/end of the EH clause; the IP associated with a
1232  // call when the runtime does its scan is the IP of the next instruction
1233  // (the one to which control will return after the call), so we need
1234  // to add 1 to the end of the clause to cover that offset. We also add
1235  // 1 to the start of the clause to make sure that the ranges reported
1236  // for all clauses are disjoint. Note that we'll need some additional
1237  // logic when machine traps are supported, since in that case the IP
1238  // that the runtime uses is the offset of the faulting instruction
1239  // itself; if such an instruction immediately follows a call but the
1240  // two belong to different clauses, we'll need to insert a nop between
1241  // them so the runtime can distinguish the point to which the call will
1242  // return from the point at which the fault occurs.
1243 
1244  const MCExpr *ClauseBegin =
1245  getOffsetPlusOne(Clause.StartLabel, FuncBeginSym);
1246  const MCExpr *ClauseEnd = getOffsetPlusOne(Clause.EndLabel, FuncBeginSym);
1247 
1248  const ClrEHUnwindMapEntry &Entry = FuncInfo.ClrEHUnwindMap[Clause.State];
1249  MachineBasicBlock *HandlerBlock = Entry.Handler.get<MachineBasicBlock *>();
1250  MCSymbol *BeginSym = getMCSymbolForMBB(Asm, HandlerBlock);
1251  const MCExpr *HandlerBegin = getOffset(BeginSym, FuncBeginSym);
1252  MCSymbol *EndSym = EndSymbolMap[Clause.State];
1253  const MCExpr *HandlerEnd = getOffset(EndSym, FuncBeginSym);
1254 
1255  uint32_t Flags = 0;
1256  switch (Entry.HandlerType) {
1257  case ClrHandlerType::Catch:
1258  // Leaving bits 0-2 clear indicates catch.
1259  break;
1261  Flags |= 1;
1262  break;
1264  Flags |= 2;
1265  break;
1266  case ClrHandlerType::Fault:
1267  Flags |= 4;
1268  break;
1269  }
1270  if (Clause.EnclosingState != MinClauseMap[Clause.State]) {
1271  // This is a "duplicate" clause; the handler needs to be entered from a
1272  // frame above the one holding the invoke.
1273  assert(Clause.EnclosingState > MinClauseMap[Clause.State]);
1274  Flags |= 8;
1275  }
1276  OS.EmitIntValue(Flags, 4);
1277 
1278  // Write the clause start/end
1279  OS.EmitValue(ClauseBegin, 4);
1280  OS.EmitValue(ClauseEnd, 4);
1281 
1282  // Write out the handler start/end
1283  OS.EmitValue(HandlerBegin, 4);
1284  OS.EmitValue(HandlerEnd, 4);
1285 
1286  // Write out the type token or filter offset
1287  assert(Entry.HandlerType != ClrHandlerType::Filter && "NYI: filters");
1288  OS.EmitIntValue(Entry.TypeToken, 4);
1289  }
1290 }
detail::concat_range< ValueT, RangeTs... > concat(RangeTs &&... Ranges)
Concatenated range across two or more ranges.
Definition: STLExtras.h:803
MBBOrBasicBlock Handler
Definition: WinEHFuncInfo.h:83
const TargetLoweringObjectFile & getObjFileLowering() const
Return information about object file lowering.
Definition: AsmPrinter.cpp:210
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:93
static int getTryAncestor(const WinEHFuncInfo &FuncInfo, int Left, int Right)
static const MCSymbolRefExpr * create(const MCSymbol *Symbol, MCContext &Ctx)
Definition: MCExpr.h:322
MBBOrBasicBlock Cleanup
Definition: WinEHFuncInfo.h:43
Compute iterated dominance frontiers using a linear time algorithm.
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:64
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:88
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:168
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:360
F(f)
MachineFunction * MF
The current machine function.
Definition: AsmPrinter.h:96
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 ...
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
static const MCBinaryExpr * createDiv(const MCExpr *LHS, const MCExpr *RHS, MCContext &Ctx)
Definition: MCExpr.h:470
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:2085
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:306
void emitExceptionTable()
Emit landing pads and actions.
Definition: EHStreamer.cpp:347
static const MCBinaryExpr * createSub(const MCExpr *LHS, const MCExpr *RHS, MCContext &Ctx)
Definition: MCExpr.h:545
MCSymbol * getFunctionBegin() const
Definition: AsmPrinter.h:208
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:460
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:112
void EmitValue(const MCExpr *Value, unsigned Size, SMLoc Loc=SMLoc())
Definition: MCStreamer.cpp:143
union llvm::WinEHHandlerType::@176 CatchObj
The CatchObj starts out life as an LLVM alloca and is eventually turned frame index.
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:183
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:112
const MCAsmInfo * MAI
Target Asm Printer information.
Definition: AsmPrinter.h:84
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:81
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:78
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.
Definition: MCStreamer.cpp:987
bool isEHLabel() const
Definition: MachineInstr.h:979
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:173
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:428
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:209
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:1963
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:224
#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 * getMCSymbol() const
LLVM Value Representation.
Definition: Value.h:73
Constant * getPersonalityFn() const
Get the personality function associated with this function.
Definition: Function.cpp:1302
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:328
const DataLayout & getDataLayout() const
Return information about data layout.
Definition: AsmPrinter.cpp:214
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:1961
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:283
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.
void tidyLandingPads(DenseMap< MCSymbol *, uintptr_t > *LPMap=nullptr)
Remap landing pad labels and remove any deleted landing pads.
A function that returns a base type.
Definition: COFF.h:262