LLVM  9.0.0svn
WinException.cpp
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1 //===-- CodeGen/AsmPrinter/WinException.cpp - Dwarf Exception Impl ------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file contains support for writing Win64 exception info into asm files.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "WinException.h"
14 #include "llvm/ADT/Twine.h"
15 #include "llvm/BinaryFormat/COFF.h"
25 #include "llvm/IR/DataLayout.h"
26 #include "llvm/IR/Mangler.h"
27 #include "llvm/IR/Module.h"
28 #include "llvm/MC/MCAsmInfo.h"
29 #include "llvm/MC/MCContext.h"
30 #include "llvm/MC/MCExpr.h"
31 #include "llvm/MC/MCSection.h"
32 #include "llvm/MC/MCStreamer.h"
33 #include "llvm/MC/MCSymbol.h"
38 using namespace llvm;
39 
41  // MSVC's EH tables are always composed of 32-bit words. All known 64-bit
42  // platforms use an imagerel32 relocation to refer to symbols.
43  useImageRel32 = (A->getDataLayout().getPointerSizeInBits() == 64);
44  isAArch64 = Asm->TM.getTargetTriple().isAArch64();
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  // On funclet exit, we emit a fake "function" end marker, so that the call
246  // to EmitWinEHHandlerData below can calculate the size of the funclet or
247  // function.
248  if (isAArch64) {
249  Asm->OutStreamer->SwitchSection(CurrentFuncletTextSection);
250  Asm->OutStreamer->EmitWinCFIFuncletOrFuncEnd();
251  MCSection *XData = Asm->OutStreamer->getAssociatedXDataSection(
252  Asm->OutStreamer->getCurrentSectionOnly());
253  Asm->OutStreamer->SwitchSection(XData);
254  }
255 
256  // Emit an UNWIND_INFO struct describing the prologue.
257  Asm->OutStreamer->EmitWinEHHandlerData();
258 
259  if (Per == EHPersonality::MSVC_CXX && shouldEmitPersonality &&
260  !CurrentFuncletEntry->isCleanupFuncletEntry()) {
261  // If this is a C++ catch funclet (or the parent function),
262  // emit a reference to the LSDA for the parent function.
264  MCSymbol *FuncInfoXData = Asm->OutContext.getOrCreateSymbol(
265  Twine("$cppxdata$", FuncLinkageName));
266  Asm->OutStreamer->EmitValue(create32bitRef(FuncInfoXData), 4);
267  } else if (Per == EHPersonality::MSVC_Win64SEH && MF->hasEHFunclets() &&
268  !CurrentFuncletEntry->isEHFuncletEntry()) {
269  // If this is the parent function in Win64 SEH, emit the LSDA immediately
270  // following .seh_handlerdata.
271  emitCSpecificHandlerTable(MF);
272  }
273 
274  // Switch back to the funclet start .text section now that we are done
275  // writing to .xdata, and emit an .seh_endproc directive to mark the end of
276  // the function.
277  Asm->OutStreamer->SwitchSection(CurrentFuncletTextSection);
278  Asm->OutStreamer->EmitWinCFIEndProc();
279  }
280 
281  // Let's make sure we don't try to end the same funclet twice.
282  CurrentFuncletEntry = nullptr;
283 }
284 
285 const MCExpr *WinException::create32bitRef(const MCSymbol *Value) {
286  if (!Value)
288  return MCSymbolRefExpr::create(Value, useImageRel32
291  Asm->OutContext);
292 }
293 
294 const MCExpr *WinException::create32bitRef(const GlobalValue *GV) {
295  if (!GV)
297  return create32bitRef(Asm->getSymbol(GV));
298 }
299 
300 const MCExpr *WinException::getLabel(const MCSymbol *Label) {
301  if (isAArch64)
303  Asm->OutContext);
304  return MCBinaryExpr::createAdd(create32bitRef(Label),
306  Asm->OutContext);
307 }
308 
309 const MCExpr *WinException::getOffset(const MCSymbol *OffsetOf,
310  const MCSymbol *OffsetFrom) {
314 }
315 
316 const MCExpr *WinException::getOffsetPlusOne(const MCSymbol *OffsetOf,
317  const MCSymbol *OffsetFrom) {
318  return MCBinaryExpr::createAdd(getOffset(OffsetOf, OffsetFrom),
320  Asm->OutContext);
321 }
322 
323 int WinException::getFrameIndexOffset(int FrameIndex,
324  const WinEHFuncInfo &FuncInfo) {
326  unsigned UnusedReg;
327  if (Asm->MAI->usesWindowsCFI()) {
328  int Offset =
330  /*IgnoreSPUpdates*/ true);
331  assert(UnusedReg ==
332  Asm->MF->getSubtarget()
335  return Offset;
336  }
337 
338  // For 32-bit, offsets should be relative to the end of the EH registration
339  // node. For 64-bit, it's relative to SP at the end of the prologue.
340  assert(FuncInfo.EHRegNodeEndOffset != INT_MAX);
341  int Offset = TFI.getFrameIndexReference(*Asm->MF, FrameIndex, UnusedReg);
342  Offset += FuncInfo.EHRegNodeEndOffset;
343  return Offset;
344 }
345 
346 namespace {
347 
348 /// Top-level state used to represent unwind to caller
349 const int NullState = -1;
350 
351 struct InvokeStateChange {
352  /// EH Label immediately after the last invoke in the previous state, or
353  /// nullptr if the previous state was the null state.
354  const MCSymbol *PreviousEndLabel;
355 
356  /// EH label immediately before the first invoke in the new state, or nullptr
357  /// if the new state is the null state.
358  const MCSymbol *NewStartLabel;
359 
360  /// State of the invoke following NewStartLabel, or NullState to indicate
361  /// the presence of calls which may unwind to caller.
362  int NewState;
363 };
364 
365 /// Iterator that reports all the invoke state changes in a range of machine
366 /// basic blocks. Changes to the null state are reported whenever a call that
367 /// may unwind to caller is encountered. The MBB range is expected to be an
368 /// entire function or funclet, and the start and end of the range are treated
369 /// as being in the NullState even if there's not an unwind-to-caller call
370 /// before the first invoke or after the last one (i.e., the first state change
371 /// reported is the first change to something other than NullState, and a
372 /// change back to NullState is always reported at the end of iteration).
373 class InvokeStateChangeIterator {
374  InvokeStateChangeIterator(const WinEHFuncInfo &EHInfo,
378  int BaseState)
379  : EHInfo(EHInfo), MFI(MFI), MFE(MFE), MBBI(MBBI), BaseState(BaseState) {
380  LastStateChange.PreviousEndLabel = nullptr;
381  LastStateChange.NewStartLabel = nullptr;
382  LastStateChange.NewState = BaseState;
383  scan();
384  }
385 
386 public:
388  range(const WinEHFuncInfo &EHInfo, MachineFunction::const_iterator Begin,
389  MachineFunction::const_iterator End, int BaseState = NullState) {
390  // Reject empty ranges to simplify bookkeeping by ensuring that we can get
391  // the end of the last block.
392  assert(Begin != End);
393  auto BlockBegin = Begin->begin();
394  auto BlockEnd = std::prev(End)->end();
395  return make_range(
396  InvokeStateChangeIterator(EHInfo, Begin, End, BlockBegin, BaseState),
397  InvokeStateChangeIterator(EHInfo, End, End, BlockEnd, BaseState));
398  }
399 
400  // Iterator methods.
401  bool operator==(const InvokeStateChangeIterator &O) const {
402  assert(BaseState == O.BaseState);
403  // Must be visiting same block.
404  if (MFI != O.MFI)
405  return false;
406  // Must be visiting same isntr.
407  if (MBBI != O.MBBI)
408  return false;
409  // At end of block/instr iteration, we can still have two distinct states:
410  // one to report the final EndLabel, and another indicating the end of the
411  // state change iteration. Check for CurrentEndLabel equality to
412  // distinguish these.
413  return CurrentEndLabel == O.CurrentEndLabel;
414  }
415 
416  bool operator!=(const InvokeStateChangeIterator &O) const {
417  return !operator==(O);
418  }
419  InvokeStateChange &operator*() { return LastStateChange; }
420  InvokeStateChange *operator->() { return &LastStateChange; }
421  InvokeStateChangeIterator &operator++() { return scan(); }
422 
423 private:
424  InvokeStateChangeIterator &scan();
425 
426  const WinEHFuncInfo &EHInfo;
427  const MCSymbol *CurrentEndLabel = nullptr;
431  InvokeStateChange LastStateChange;
432  bool VisitingInvoke = false;
433  int BaseState;
434 };
435 
436 } // end anonymous namespace
437 
438 InvokeStateChangeIterator &InvokeStateChangeIterator::scan() {
439  bool IsNewBlock = false;
440  for (; MFI != MFE; ++MFI, IsNewBlock = true) {
441  if (IsNewBlock)
442  MBBI = MFI->begin();
443  for (auto MBBE = MFI->end(); MBBI != MBBE; ++MBBI) {
444  const MachineInstr &MI = *MBBI;
445  if (!VisitingInvoke && LastStateChange.NewState != BaseState &&
447  // Indicate a change of state to the null state. We don't have
448  // start/end EH labels handy but the caller won't expect them for
449  // null state regions.
450  LastStateChange.PreviousEndLabel = CurrentEndLabel;
451  LastStateChange.NewStartLabel = nullptr;
452  LastStateChange.NewState = BaseState;
453  CurrentEndLabel = nullptr;
454  // Don't re-visit this instr on the next scan
455  ++MBBI;
456  return *this;
457  }
458 
459  // All other state changes are at EH labels before/after invokes.
460  if (!MI.isEHLabel())
461  continue;
462  MCSymbol *Label = MI.getOperand(0).getMCSymbol();
463  if (Label == CurrentEndLabel) {
464  VisitingInvoke = false;
465  continue;
466  }
467  auto InvokeMapIter = EHInfo.LabelToStateMap.find(Label);
468  // Ignore EH labels that aren't the ones inserted before an invoke
469  if (InvokeMapIter == EHInfo.LabelToStateMap.end())
470  continue;
471  auto &StateAndEnd = InvokeMapIter->second;
472  int NewState = StateAndEnd.first;
473  // Keep track of the fact that we're between EH start/end labels so
474  // we know not to treat the inoke we'll see as unwinding to caller.
475  VisitingInvoke = true;
476  if (NewState == LastStateChange.NewState) {
477  // The state isn't actually changing here. Record the new end and
478  // keep going.
479  CurrentEndLabel = StateAndEnd.second;
480  continue;
481  }
482  // Found a state change to report
483  LastStateChange.PreviousEndLabel = CurrentEndLabel;
484  LastStateChange.NewStartLabel = Label;
485  LastStateChange.NewState = NewState;
486  // Start keeping track of the new current end
487  CurrentEndLabel = StateAndEnd.second;
488  // Don't re-visit this instr on the next scan
489  ++MBBI;
490  return *this;
491  }
492  }
493  // Iteration hit the end of the block range.
494  if (LastStateChange.NewState != BaseState) {
495  // Report the end of the last new state
496  LastStateChange.PreviousEndLabel = CurrentEndLabel;
497  LastStateChange.NewStartLabel = nullptr;
498  LastStateChange.NewState = BaseState;
499  // Leave CurrentEndLabel non-null to distinguish this state from end.
500  assert(CurrentEndLabel != nullptr);
501  return *this;
502  }
503  // We've reported all state changes and hit the end state.
504  CurrentEndLabel = nullptr;
505  return *this;
506 }
507 
508 /// Emit the language-specific data that __C_specific_handler expects. This
509 /// handler lives in the x64 Microsoft C runtime and allows catching or cleaning
510 /// up after faults with __try, __except, and __finally. The typeinfo values
511 /// are not really RTTI data, but pointers to filter functions that return an
512 /// integer (1, 0, or -1) indicating how to handle the exception. For __finally
513 /// blocks and other cleanups, the landing pad label is zero, and the filter
514 /// function is actually a cleanup handler with the same prototype. A catch-all
515 /// entry is modeled with a null filter function field and a non-zero landing
516 /// pad label.
517 ///
518 /// Possible filter function return values:
519 /// EXCEPTION_EXECUTE_HANDLER (1):
520 /// Jump to the landing pad label after cleanups.
521 /// EXCEPTION_CONTINUE_SEARCH (0):
522 /// Continue searching this table or continue unwinding.
523 /// EXCEPTION_CONTINUE_EXECUTION (-1):
524 /// Resume execution at the trapping PC.
525 ///
526 /// Inferred table structure:
527 /// struct Table {
528 /// int NumEntries;
529 /// struct Entry {
530 /// imagerel32 LabelStart;
531 /// imagerel32 LabelEnd;
532 /// imagerel32 FilterOrFinally; // One means catch-all.
533 /// imagerel32 LabelLPad; // Zero means __finally.
534 /// } Entries[NumEntries];
535 /// };
536 void WinException::emitCSpecificHandlerTable(const MachineFunction *MF) {
537  auto &OS = *Asm->OutStreamer;
538  MCContext &Ctx = Asm->OutContext;
539  const WinEHFuncInfo &FuncInfo = *MF->getWinEHFuncInfo();
540 
541  bool VerboseAsm = OS.isVerboseAsm();
542  auto AddComment = [&](const Twine &Comment) {
543  if (VerboseAsm)
544  OS.AddComment(Comment);
545  };
546 
547  if (!isAArch64) {
548  // Emit a label assignment with the SEH frame offset so we can use it for
549  // llvm.eh.recoverfp.
550  StringRef FLinkageName =
552  MCSymbol *ParentFrameOffset =
553  Ctx.getOrCreateParentFrameOffsetSymbol(FLinkageName);
554  const MCExpr *MCOffset =
556  Asm->OutStreamer->EmitAssignment(ParentFrameOffset, MCOffset);
557  }
558 
559  // Use the assembler to compute the number of table entries through label
560  // difference and division.
561  MCSymbol *TableBegin =
562  Ctx.createTempSymbol("lsda_begin", /*AlwaysAddSuffix=*/true);
563  MCSymbol *TableEnd =
564  Ctx.createTempSymbol("lsda_end", /*AlwaysAddSuffix=*/true);
565  const MCExpr *LabelDiff = getOffset(TableEnd, TableBegin);
566  const MCExpr *EntrySize = MCConstantExpr::create(16, Ctx);
567  const MCExpr *EntryCount = MCBinaryExpr::createDiv(LabelDiff, EntrySize, Ctx);
568  AddComment("Number of call sites");
569  OS.EmitValue(EntryCount, 4);
570 
571  OS.EmitLabel(TableBegin);
572 
573  // Iterate over all the invoke try ranges. Unlike MSVC, LLVM currently only
574  // models exceptions from invokes. LLVM also allows arbitrary reordering of
575  // the code, so our tables end up looking a bit different. Rather than
576  // trying to match MSVC's tables exactly, we emit a denormalized table. For
577  // each range of invokes in the same state, we emit table entries for all
578  // the actions that would be taken in that state. This means our tables are
579  // slightly bigger, which is OK.
580  const MCSymbol *LastStartLabel = nullptr;
581  int LastEHState = -1;
582  // Break out before we enter into a finally funclet.
583  // FIXME: We need to emit separate EH tables for cleanups.
585  MachineFunction::const_iterator Stop = std::next(MF->begin());
586  while (Stop != End && !Stop->isEHFuncletEntry())
587  ++Stop;
588  for (const auto &StateChange :
589  InvokeStateChangeIterator::range(FuncInfo, MF->begin(), Stop)) {
590  // Emit all the actions for the state we just transitioned out of
591  // if it was not the null state
592  if (LastEHState != -1)
593  emitSEHActionsForRange(FuncInfo, LastStartLabel,
594  StateChange.PreviousEndLabel, LastEHState);
595  LastStartLabel = StateChange.NewStartLabel;
596  LastEHState = StateChange.NewState;
597  }
598 
599  OS.EmitLabel(TableEnd);
600 }
601 
602 void WinException::emitSEHActionsForRange(const WinEHFuncInfo &FuncInfo,
603  const MCSymbol *BeginLabel,
604  const MCSymbol *EndLabel, int State) {
605  auto &OS = *Asm->OutStreamer;
606  MCContext &Ctx = Asm->OutContext;
607  bool VerboseAsm = OS.isVerboseAsm();
608  auto AddComment = [&](const Twine &Comment) {
609  if (VerboseAsm)
610  OS.AddComment(Comment);
611  };
612 
613  assert(BeginLabel && EndLabel);
614  while (State != -1) {
615  const SEHUnwindMapEntry &UME = FuncInfo.SEHUnwindMap[State];
616  const MCExpr *FilterOrFinally;
617  const MCExpr *ExceptOrNull;
618  auto *Handler = UME.Handler.get<MachineBasicBlock *>();
619  if (UME.IsFinally) {
620  FilterOrFinally = create32bitRef(getMCSymbolForMBB(Asm, Handler));
621  ExceptOrNull = MCConstantExpr::create(0, Ctx);
622  } else {
623  // For an except, the filter can be 1 (catch-all) or a function
624  // label.
625  FilterOrFinally = UME.Filter ? create32bitRef(UME.Filter)
626  : MCConstantExpr::create(1, Ctx);
627  ExceptOrNull = create32bitRef(Handler->getSymbol());
628  }
629 
630  AddComment("LabelStart");
631  OS.EmitValue(getLabel(BeginLabel), 4);
632  AddComment("LabelEnd");
633  OS.EmitValue(getLabel(EndLabel), 4);
634  AddComment(UME.IsFinally ? "FinallyFunclet" : UME.Filter ? "FilterFunction"
635  : "CatchAll");
636  OS.EmitValue(FilterOrFinally, 4);
637  AddComment(UME.IsFinally ? "Null" : "ExceptionHandler");
638  OS.EmitValue(ExceptOrNull, 4);
639 
640  assert(UME.ToState < State && "states should decrease");
641  State = UME.ToState;
642  }
643 }
644 
645 void WinException::emitCXXFrameHandler3Table(const MachineFunction *MF) {
646  const Function &F = MF->getFunction();
647  auto &OS = *Asm->OutStreamer;
648  const WinEHFuncInfo &FuncInfo = *MF->getWinEHFuncInfo();
649 
651 
653  MCSymbol *FuncInfoXData = nullptr;
654  if (shouldEmitPersonality) {
655  // If we're 64-bit, emit a pointer to the C++ EH data, and build a map from
656  // IPs to state numbers.
657  FuncInfoXData =
658  Asm->OutContext.getOrCreateSymbol(Twine("$cppxdata$", FuncLinkageName));
659  computeIP2StateTable(MF, FuncInfo, IPToStateTable);
660  } else {
661  FuncInfoXData = Asm->OutContext.getOrCreateLSDASymbol(FuncLinkageName);
662  }
663 
664  int UnwindHelpOffset = 0;
665  if (Asm->MAI->usesWindowsCFI())
666  UnwindHelpOffset =
667  getFrameIndexOffset(FuncInfo.UnwindHelpFrameIdx, FuncInfo);
668 
669  MCSymbol *UnwindMapXData = nullptr;
670  MCSymbol *TryBlockMapXData = nullptr;
671  MCSymbol *IPToStateXData = nullptr;
672  if (!FuncInfo.CxxUnwindMap.empty())
673  UnwindMapXData = Asm->OutContext.getOrCreateSymbol(
674  Twine("$stateUnwindMap$", FuncLinkageName));
675  if (!FuncInfo.TryBlockMap.empty())
676  TryBlockMapXData =
677  Asm->OutContext.getOrCreateSymbol(Twine("$tryMap$", FuncLinkageName));
678  if (!IPToStateTable.empty())
679  IPToStateXData =
680  Asm->OutContext.getOrCreateSymbol(Twine("$ip2state$", FuncLinkageName));
681 
682  bool VerboseAsm = OS.isVerboseAsm();
683  auto AddComment = [&](const Twine &Comment) {
684  if (VerboseAsm)
685  OS.AddComment(Comment);
686  };
687 
688  // FuncInfo {
689  // uint32_t MagicNumber
690  // int32_t MaxState;
691  // UnwindMapEntry *UnwindMap;
692  // uint32_t NumTryBlocks;
693  // TryBlockMapEntry *TryBlockMap;
694  // uint32_t IPMapEntries; // always 0 for x86
695  // IPToStateMapEntry *IPToStateMap; // always 0 for x86
696  // uint32_t UnwindHelp; // non-x86 only
697  // ESTypeList *ESTypeList;
698  // int32_t EHFlags;
699  // }
700  // EHFlags & 1 -> Synchronous exceptions only, no async exceptions.
701  // EHFlags & 2 -> ???
702  // EHFlags & 4 -> The function is noexcept(true), unwinding can't continue.
703  OS.EmitValueToAlignment(4);
704  OS.EmitLabel(FuncInfoXData);
705 
706  AddComment("MagicNumber");
707  OS.EmitIntValue(0x19930522, 4);
708 
709  AddComment("MaxState");
710  OS.EmitIntValue(FuncInfo.CxxUnwindMap.size(), 4);
711 
712  AddComment("UnwindMap");
713  OS.EmitValue(create32bitRef(UnwindMapXData), 4);
714 
715  AddComment("NumTryBlocks");
716  OS.EmitIntValue(FuncInfo.TryBlockMap.size(), 4);
717 
718  AddComment("TryBlockMap");
719  OS.EmitValue(create32bitRef(TryBlockMapXData), 4);
720 
721  AddComment("IPMapEntries");
722  OS.EmitIntValue(IPToStateTable.size(), 4);
723 
724  AddComment("IPToStateXData");
725  OS.EmitValue(create32bitRef(IPToStateXData), 4);
726 
727  if (Asm->MAI->usesWindowsCFI()) {
728  AddComment("UnwindHelp");
729  OS.EmitIntValue(UnwindHelpOffset, 4);
730  }
731 
732  AddComment("ESTypeList");
733  OS.EmitIntValue(0, 4);
734 
735  AddComment("EHFlags");
736  OS.EmitIntValue(1, 4);
737 
738  // UnwindMapEntry {
739  // int32_t ToState;
740  // void (*Action)();
741  // };
742  if (UnwindMapXData) {
743  OS.EmitLabel(UnwindMapXData);
744  for (const CxxUnwindMapEntry &UME : FuncInfo.CxxUnwindMap) {
745  MCSymbol *CleanupSym =
747  AddComment("ToState");
748  OS.EmitIntValue(UME.ToState, 4);
749 
750  AddComment("Action");
751  OS.EmitValue(create32bitRef(CleanupSym), 4);
752  }
753  }
754 
755  // TryBlockMap {
756  // int32_t TryLow;
757  // int32_t TryHigh;
758  // int32_t CatchHigh;
759  // int32_t NumCatches;
760  // HandlerType *HandlerArray;
761  // };
762  if (TryBlockMapXData) {
763  OS.EmitLabel(TryBlockMapXData);
764  SmallVector<MCSymbol *, 1> HandlerMaps;
765  for (size_t I = 0, E = FuncInfo.TryBlockMap.size(); I != E; ++I) {
766  const WinEHTryBlockMapEntry &TBME = FuncInfo.TryBlockMap[I];
767 
768  MCSymbol *HandlerMapXData = nullptr;
769  if (!TBME.HandlerArray.empty())
770  HandlerMapXData =
771  Asm->OutContext.getOrCreateSymbol(Twine("$handlerMap$")
772  .concat(Twine(I))
773  .concat("$")
774  .concat(FuncLinkageName));
775  HandlerMaps.push_back(HandlerMapXData);
776 
777  // TBMEs should form intervals.
778  assert(0 <= TBME.TryLow && "bad trymap interval");
779  assert(TBME.TryLow <= TBME.TryHigh && "bad trymap interval");
780  assert(TBME.TryHigh < TBME.CatchHigh && "bad trymap interval");
781  assert(TBME.CatchHigh < int(FuncInfo.CxxUnwindMap.size()) &&
782  "bad trymap interval");
783 
784  AddComment("TryLow");
785  OS.EmitIntValue(TBME.TryLow, 4);
786 
787  AddComment("TryHigh");
788  OS.EmitIntValue(TBME.TryHigh, 4);
789 
790  AddComment("CatchHigh");
791  OS.EmitIntValue(TBME.CatchHigh, 4);
792 
793  AddComment("NumCatches");
794  OS.EmitIntValue(TBME.HandlerArray.size(), 4);
795 
796  AddComment("HandlerArray");
797  OS.EmitValue(create32bitRef(HandlerMapXData), 4);
798  }
799 
800  // All funclets use the same parent frame offset currently.
801  unsigned ParentFrameOffset = 0;
802  if (shouldEmitPersonality) {
804  ParentFrameOffset = TFI->getWinEHParentFrameOffset(*MF);
805  }
806 
807  for (size_t I = 0, E = FuncInfo.TryBlockMap.size(); I != E; ++I) {
808  const WinEHTryBlockMapEntry &TBME = FuncInfo.TryBlockMap[I];
809  MCSymbol *HandlerMapXData = HandlerMaps[I];
810  if (!HandlerMapXData)
811  continue;
812  // HandlerType {
813  // int32_t Adjectives;
814  // TypeDescriptor *Type;
815  // int32_t CatchObjOffset;
816  // void (*Handler)();
817  // int32_t ParentFrameOffset; // x64 and AArch64 only
818  // };
819  OS.EmitLabel(HandlerMapXData);
820  for (const WinEHHandlerType &HT : TBME.HandlerArray) {
821  // Get the frame escape label with the offset of the catch object. If
822  // the index is INT_MAX, then there is no catch object, and we should
823  // emit an offset of zero, indicating that no copy will occur.
824  const MCExpr *FrameAllocOffsetRef = nullptr;
825  if (HT.CatchObj.FrameIndex != INT_MAX) {
826  int Offset = getFrameIndexOffset(HT.CatchObj.FrameIndex, FuncInfo);
827  assert(Offset != 0 && "Illegal offset for catch object!");
828  FrameAllocOffsetRef = MCConstantExpr::create(Offset, Asm->OutContext);
829  } else {
830  FrameAllocOffsetRef = MCConstantExpr::create(0, Asm->OutContext);
831  }
832 
833  MCSymbol *HandlerSym =
835 
836  AddComment("Adjectives");
837  OS.EmitIntValue(HT.Adjectives, 4);
838 
839  AddComment("Type");
840  OS.EmitValue(create32bitRef(HT.TypeDescriptor), 4);
841 
842  AddComment("CatchObjOffset");
843  OS.EmitValue(FrameAllocOffsetRef, 4);
844 
845  AddComment("Handler");
846  OS.EmitValue(create32bitRef(HandlerSym), 4);
847 
848  if (shouldEmitPersonality) {
849  AddComment("ParentFrameOffset");
850  OS.EmitIntValue(ParentFrameOffset, 4);
851  }
852  }
853  }
854  }
855 
856  // IPToStateMapEntry {
857  // void *IP;
858  // int32_t State;
859  // };
860  if (IPToStateXData) {
861  OS.EmitLabel(IPToStateXData);
862  for (auto &IPStatePair : IPToStateTable) {
863  AddComment("IP");
864  OS.EmitValue(IPStatePair.first, 4);
865  AddComment("ToState");
866  OS.EmitIntValue(IPStatePair.second, 4);
867  }
868  }
869 }
870 
871 void WinException::computeIP2StateTable(
872  const MachineFunction *MF, const WinEHFuncInfo &FuncInfo,
873  SmallVectorImpl<std::pair<const MCExpr *, int>> &IPToStateTable) {
874 
875  for (MachineFunction::const_iterator FuncletStart = MF->begin(),
876  FuncletEnd = MF->begin(),
877  End = MF->end();
878  FuncletStart != End; FuncletStart = FuncletEnd) {
879  // Find the end of the funclet
880  while (++FuncletEnd != End) {
881  if (FuncletEnd->isEHFuncletEntry()) {
882  break;
883  }
884  }
885 
886  // Don't emit ip2state entries for cleanup funclets. Any interesting
887  // exceptional actions in cleanups must be handled in a separate IR
888  // function.
889  if (FuncletStart->isCleanupFuncletEntry())
890  continue;
891 
892  MCSymbol *StartLabel;
893  int BaseState;
894  if (FuncletStart == MF->begin()) {
895  BaseState = NullState;
896  StartLabel = Asm->getFunctionBegin();
897  } else {
898  auto *FuncletPad =
899  cast<FuncletPadInst>(FuncletStart->getBasicBlock()->getFirstNonPHI());
900  assert(FuncInfo.FuncletBaseStateMap.count(FuncletPad) != 0);
901  BaseState = FuncInfo.FuncletBaseStateMap.find(FuncletPad)->second;
902  StartLabel = getMCSymbolForMBB(Asm, &*FuncletStart);
903  }
904  assert(StartLabel && "need local function start label");
905  IPToStateTable.push_back(
906  std::make_pair(create32bitRef(StartLabel), BaseState));
907 
908  for (const auto &StateChange : InvokeStateChangeIterator::range(
909  FuncInfo, FuncletStart, FuncletEnd, BaseState)) {
910  // Compute the label to report as the start of this entry; use the EH
911  // start label for the invoke if we have one, otherwise (this is a call
912  // which may unwind to our caller and does not have an EH start label, so)
913  // use the previous end label.
914  const MCSymbol *ChangeLabel = StateChange.NewStartLabel;
915  if (!ChangeLabel)
916  ChangeLabel = StateChange.PreviousEndLabel;
917  // Emit an entry indicating that PCs after 'Label' have this EH state.
918  IPToStateTable.push_back(
919  std::make_pair(getLabel(ChangeLabel), StateChange.NewState));
920  // FIXME: assert that NewState is between CatchLow and CatchHigh.
921  }
922  }
923 }
924 
925 void WinException::emitEHRegistrationOffsetLabel(const WinEHFuncInfo &FuncInfo,
926  StringRef FLinkageName) {
927  // Outlined helpers called by the EH runtime need to know the offset of the EH
928  // registration in order to recover the parent frame pointer. Now that we know
929  // we've code generated the parent, we can emit the label assignment that
930  // those helpers use to get the offset of the registration node.
931 
932  // Compute the parent frame offset. The EHRegNodeFrameIndex will be invalid if
933  // after optimization all the invokes were eliminated. We still need to emit
934  // the parent frame offset label, but it should be garbage and should never be
935  // used.
936  int64_t Offset = 0;
937  int FI = FuncInfo.EHRegNodeFrameIndex;
938  if (FI != INT_MAX) {
940  Offset = TFI->getNonLocalFrameIndexReference(*Asm->MF, FI);
941  }
942 
943  MCContext &Ctx = Asm->OutContext;
944  MCSymbol *ParentFrameOffset =
945  Ctx.getOrCreateParentFrameOffsetSymbol(FLinkageName);
946  Asm->OutStreamer->EmitAssignment(ParentFrameOffset,
947  MCConstantExpr::create(Offset, Ctx));
948 }
949 
950 /// Emit the language-specific data that _except_handler3 and 4 expect. This is
951 /// functionally equivalent to the __C_specific_handler table, except it is
952 /// indexed by state number instead of IP.
953 void WinException::emitExceptHandlerTable(const MachineFunction *MF) {
954  MCStreamer &OS = *Asm->OutStreamer;
955  const Function &F = MF->getFunction();
957 
958  bool VerboseAsm = OS.isVerboseAsm();
959  auto AddComment = [&](const Twine &Comment) {
960  if (VerboseAsm)
961  OS.AddComment(Comment);
962  };
963 
964  const WinEHFuncInfo &FuncInfo = *MF->getWinEHFuncInfo();
965  emitEHRegistrationOffsetLabel(FuncInfo, FLinkageName);
966 
967  // Emit the __ehtable label that we use for llvm.x86.seh.lsda.
968  MCSymbol *LSDALabel = Asm->OutContext.getOrCreateLSDASymbol(FLinkageName);
969  OS.EmitValueToAlignment(4);
970  OS.EmitLabel(LSDALabel);
971 
972  const Function *Per =
974  StringRef PerName = Per->getName();
975  int BaseState = -1;
976  if (PerName == "_except_handler4") {
977  // The LSDA for _except_handler4 starts with this struct, followed by the
978  // scope table:
979  //
980  // struct EH4ScopeTable {
981  // int32_t GSCookieOffset;
982  // int32_t GSCookieXOROffset;
983  // int32_t EHCookieOffset;
984  // int32_t EHCookieXOROffset;
985  // ScopeTableEntry ScopeRecord[];
986  // };
987  //
988  // Offsets are %ebp relative.
989  //
990  // The GS cookie is present only if the function needs stack protection.
991  // GSCookieOffset = -2 means that GS cookie is not used.
992  //
993  // The EH cookie is always present.
994  //
995  // Check is done the following way:
996  // (ebp+CookieXOROffset) ^ [ebp+CookieOffset] == _security_cookie
997 
998  // Retrieve the Guard Stack slot.
999  int GSCookieOffset = -2;
1000  const MachineFrameInfo &MFI = MF->getFrameInfo();
1001  if (MFI.hasStackProtectorIndex()) {
1002  unsigned UnusedReg;
1003  const TargetFrameLowering *TFI = MF->getSubtarget().getFrameLowering();
1004  int SSPIdx = MFI.getStackProtectorIndex();
1005  GSCookieOffset = TFI->getFrameIndexReference(*MF, SSPIdx, UnusedReg);
1006  }
1007 
1008  // Retrieve the EH Guard slot.
1009  // TODO(etienneb): Get rid of this value and change it for and assertion.
1010  int EHCookieOffset = 9999;
1011  if (FuncInfo.EHGuardFrameIndex != INT_MAX) {
1012  unsigned UnusedReg;
1013  const TargetFrameLowering *TFI = MF->getSubtarget().getFrameLowering();
1014  int EHGuardIdx = FuncInfo.EHGuardFrameIndex;
1015  EHCookieOffset = TFI->getFrameIndexReference(*MF, EHGuardIdx, UnusedReg);
1016  }
1017 
1018  AddComment("GSCookieOffset");
1019  OS.EmitIntValue(GSCookieOffset, 4);
1020  AddComment("GSCookieXOROffset");
1021  OS.EmitIntValue(0, 4);
1022  AddComment("EHCookieOffset");
1023  OS.EmitIntValue(EHCookieOffset, 4);
1024  AddComment("EHCookieXOROffset");
1025  OS.EmitIntValue(0, 4);
1026  BaseState = -2;
1027  }
1028 
1029  assert(!FuncInfo.SEHUnwindMap.empty());
1030  for (const SEHUnwindMapEntry &UME : FuncInfo.SEHUnwindMap) {
1031  auto *Handler = UME.Handler.get<MachineBasicBlock *>();
1032  const MCSymbol *ExceptOrFinally =
1033  UME.IsFinally ? getMCSymbolForMBB(Asm, Handler) : Handler->getSymbol();
1034  // -1 is usually the base state for "unwind to caller", but for
1035  // _except_handler4 it's -2. Do that replacement here if necessary.
1036  int ToState = UME.ToState == -1 ? BaseState : UME.ToState;
1037  AddComment("ToState");
1038  OS.EmitIntValue(ToState, 4);
1039  AddComment(UME.IsFinally ? "Null" : "FilterFunction");
1040  OS.EmitValue(create32bitRef(UME.Filter), 4);
1041  AddComment(UME.IsFinally ? "FinallyFunclet" : "ExceptionHandler");
1042  OS.EmitValue(create32bitRef(ExceptOrFinally), 4);
1043  }
1044 }
1045 
1046 static int getTryRank(const WinEHFuncInfo &FuncInfo, int State) {
1047  int Rank = 0;
1048  while (State != -1) {
1049  ++Rank;
1050  State = FuncInfo.ClrEHUnwindMap[State].TryParentState;
1051  }
1052  return Rank;
1053 }
1054 
1055 static int getTryAncestor(const WinEHFuncInfo &FuncInfo, int Left, int Right) {
1056  int LeftRank = getTryRank(FuncInfo, Left);
1057  int RightRank = getTryRank(FuncInfo, Right);
1058 
1059  while (LeftRank < RightRank) {
1060  Right = FuncInfo.ClrEHUnwindMap[Right].TryParentState;
1061  --RightRank;
1062  }
1063 
1064  while (RightRank < LeftRank) {
1065  Left = FuncInfo.ClrEHUnwindMap[Left].TryParentState;
1066  --LeftRank;
1067  }
1068 
1069  while (Left != Right) {
1070  Left = FuncInfo.ClrEHUnwindMap[Left].TryParentState;
1071  Right = FuncInfo.ClrEHUnwindMap[Right].TryParentState;
1072  }
1073 
1074  return Left;
1075 }
1076 
1077 void WinException::emitCLRExceptionTable(const MachineFunction *MF) {
1078  // CLR EH "states" are really just IDs that identify handlers/funclets;
1079  // states, handlers, and funclets all have 1:1 mappings between them, and a
1080  // handler/funclet's "state" is its index in the ClrEHUnwindMap.
1081  MCStreamer &OS = *Asm->OutStreamer;
1082  const WinEHFuncInfo &FuncInfo = *MF->getWinEHFuncInfo();
1083  MCSymbol *FuncBeginSym = Asm->getFunctionBegin();
1084  MCSymbol *FuncEndSym = Asm->getFunctionEnd();
1085 
1086  // A ClrClause describes a protected region.
1087  struct ClrClause {
1088  const MCSymbol *StartLabel; // Start of protected region
1089  const MCSymbol *EndLabel; // End of protected region
1090  int State; // Index of handler protecting the protected region
1091  int EnclosingState; // Index of funclet enclosing the protected region
1092  };
1093  SmallVector<ClrClause, 8> Clauses;
1094 
1095  // Build a map from handler MBBs to their corresponding states (i.e. their
1096  // indices in the ClrEHUnwindMap).
1097  int NumStates = FuncInfo.ClrEHUnwindMap.size();
1098  assert(NumStates > 0 && "Don't need exception table!");
1100  for (int State = 0; State < NumStates; ++State) {
1101  MachineBasicBlock *HandlerBlock =
1102  FuncInfo.ClrEHUnwindMap[State].Handler.get<MachineBasicBlock *>();
1103  HandlerStates[HandlerBlock] = State;
1104  // Use this loop through all handlers to verify our assumption (used in
1105  // the MinEnclosingState computation) that enclosing funclets have lower
1106  // state numbers than their enclosed funclets.
1107  assert(FuncInfo.ClrEHUnwindMap[State].HandlerParentState < State &&
1108  "ill-formed state numbering");
1109  }
1110  // Map the main function to the NullState.
1111  HandlerStates[&MF->front()] = NullState;
1112 
1113  // Write out a sentinel indicating the end of the standard (Windows) xdata
1114  // and the start of the additional (CLR) info.
1115  OS.EmitIntValue(0xffffffff, 4);
1116  // Write out the number of funclets
1117  OS.EmitIntValue(NumStates, 4);
1118 
1119  // Walk the machine blocks/instrs, computing and emitting a few things:
1120  // 1. Emit a list of the offsets to each handler entry, in lexical order.
1121  // 2. Compute a map (EndSymbolMap) from each funclet to the symbol at its end.
1122  // 3. Compute the list of ClrClauses, in the required order (inner before
1123  // outer, earlier before later; the order by which a forward scan with
1124  // early termination will find the innermost enclosing clause covering
1125  // a given address).
1126  // 4. A map (MinClauseMap) from each handler index to the index of the
1127  // outermost funclet/function which contains a try clause targeting the
1128  // key handler. This will be used to determine IsDuplicate-ness when
1129  // emitting ClrClauses. The NullState value is used to indicate that the
1130  // top-level function contains a try clause targeting the key handler.
1131  // HandlerStack is a stack of (PendingStartLabel, PendingState) pairs for
1132  // try regions we entered before entering the PendingState try but which
1133  // we haven't yet exited.
1135  // EndSymbolMap and MinClauseMap are maps described above.
1136  std::unique_ptr<MCSymbol *[]> EndSymbolMap(new MCSymbol *[NumStates]);
1137  SmallVector<int, 4> MinClauseMap((size_t)NumStates, NumStates);
1138 
1139  // Visit the root function and each funclet.
1140  for (MachineFunction::const_iterator FuncletStart = MF->begin(),
1141  FuncletEnd = MF->begin(),
1142  End = MF->end();
1143  FuncletStart != End; FuncletStart = FuncletEnd) {
1144  int FuncletState = HandlerStates[&*FuncletStart];
1145  // Find the end of the funclet
1146  MCSymbol *EndSymbol = FuncEndSym;
1147  while (++FuncletEnd != End) {
1148  if (FuncletEnd->isEHFuncletEntry()) {
1149  EndSymbol = getMCSymbolForMBB(Asm, &*FuncletEnd);
1150  break;
1151  }
1152  }
1153  // Emit the function/funclet end and, if this is a funclet (and not the
1154  // root function), record it in the EndSymbolMap.
1155  OS.EmitValue(getOffset(EndSymbol, FuncBeginSym), 4);
1156  if (FuncletState != NullState) {
1157  // Record the end of the handler.
1158  EndSymbolMap[FuncletState] = EndSymbol;
1159  }
1160 
1161  // Walk the state changes in this function/funclet and compute its clauses.
1162  // Funclets always start in the null state.
1163  const MCSymbol *CurrentStartLabel = nullptr;
1164  int CurrentState = NullState;
1165  assert(HandlerStack.empty());
1166  for (const auto &StateChange :
1167  InvokeStateChangeIterator::range(FuncInfo, FuncletStart, FuncletEnd)) {
1168  // Close any try regions we're not still under
1169  int StillPendingState =
1170  getTryAncestor(FuncInfo, CurrentState, StateChange.NewState);
1171  while (CurrentState != StillPendingState) {
1172  assert(CurrentState != NullState &&
1173  "Failed to find still-pending state!");
1174  // Close the pending clause
1175  Clauses.push_back({CurrentStartLabel, StateChange.PreviousEndLabel,
1176  CurrentState, FuncletState});
1177  // Now the next-outer try region is current
1178  CurrentState = FuncInfo.ClrEHUnwindMap[CurrentState].TryParentState;
1179  // Pop the new start label from the handler stack if we've exited all
1180  // inner try regions of the corresponding try region.
1181  if (HandlerStack.back().second == CurrentState)
1182  CurrentStartLabel = HandlerStack.pop_back_val().first;
1183  }
1184 
1185  if (StateChange.NewState != CurrentState) {
1186  // For each clause we're starting, update the MinClauseMap so we can
1187  // know which is the topmost funclet containing a clause targeting
1188  // it.
1189  for (int EnteredState = StateChange.NewState;
1190  EnteredState != CurrentState;
1191  EnteredState =
1192  FuncInfo.ClrEHUnwindMap[EnteredState].TryParentState) {
1193  int &MinEnclosingState = MinClauseMap[EnteredState];
1194  if (FuncletState < MinEnclosingState)
1195  MinEnclosingState = FuncletState;
1196  }
1197  // Save the previous current start/label on the stack and update to
1198  // the newly-current start/state.
1199  HandlerStack.emplace_back(CurrentStartLabel, CurrentState);
1200  CurrentStartLabel = StateChange.NewStartLabel;
1201  CurrentState = StateChange.NewState;
1202  }
1203  }
1204  assert(HandlerStack.empty());
1205  }
1206 
1207  // Now emit the clause info, starting with the number of clauses.
1208  OS.EmitIntValue(Clauses.size(), 4);
1209  for (ClrClause &Clause : Clauses) {
1210  // Emit a CORINFO_EH_CLAUSE :
1211  /*
1212  struct CORINFO_EH_CLAUSE
1213  {
1214  CORINFO_EH_CLAUSE_FLAGS Flags; // actually a CorExceptionFlag
1215  DWORD TryOffset;
1216  DWORD TryLength; // actually TryEndOffset
1217  DWORD HandlerOffset;
1218  DWORD HandlerLength; // actually HandlerEndOffset
1219  union
1220  {
1221  DWORD ClassToken; // use for catch clauses
1222  DWORD FilterOffset; // use for filter clauses
1223  };
1224  };
1225 
1226  enum CORINFO_EH_CLAUSE_FLAGS
1227  {
1228  CORINFO_EH_CLAUSE_NONE = 0,
1229  CORINFO_EH_CLAUSE_FILTER = 0x0001, // This clause is for a filter
1230  CORINFO_EH_CLAUSE_FINALLY = 0x0002, // This clause is a finally clause
1231  CORINFO_EH_CLAUSE_FAULT = 0x0004, // This clause is a fault clause
1232  };
1233  typedef enum CorExceptionFlag
1234  {
1235  COR_ILEXCEPTION_CLAUSE_NONE,
1236  COR_ILEXCEPTION_CLAUSE_FILTER = 0x0001, // This is a filter clause
1237  COR_ILEXCEPTION_CLAUSE_FINALLY = 0x0002, // This is a finally clause
1238  COR_ILEXCEPTION_CLAUSE_FAULT = 0x0004, // This is a fault clause
1239  COR_ILEXCEPTION_CLAUSE_DUPLICATED = 0x0008, // duplicated clause. This
1240  // clause was duplicated
1241  // to a funclet which was
1242  // pulled out of line
1243  } CorExceptionFlag;
1244  */
1245  // Add 1 to the start/end of the EH clause; the IP associated with a
1246  // call when the runtime does its scan is the IP of the next instruction
1247  // (the one to which control will return after the call), so we need
1248  // to add 1 to the end of the clause to cover that offset. We also add
1249  // 1 to the start of the clause to make sure that the ranges reported
1250  // for all clauses are disjoint. Note that we'll need some additional
1251  // logic when machine traps are supported, since in that case the IP
1252  // that the runtime uses is the offset of the faulting instruction
1253  // itself; if such an instruction immediately follows a call but the
1254  // two belong to different clauses, we'll need to insert a nop between
1255  // them so the runtime can distinguish the point to which the call will
1256  // return from the point at which the fault occurs.
1257 
1258  const MCExpr *ClauseBegin =
1259  getOffsetPlusOne(Clause.StartLabel, FuncBeginSym);
1260  const MCExpr *ClauseEnd = getOffsetPlusOne(Clause.EndLabel, FuncBeginSym);
1261 
1262  const ClrEHUnwindMapEntry &Entry = FuncInfo.ClrEHUnwindMap[Clause.State];
1263  MachineBasicBlock *HandlerBlock = Entry.Handler.get<MachineBasicBlock *>();
1264  MCSymbol *BeginSym = getMCSymbolForMBB(Asm, HandlerBlock);
1265  const MCExpr *HandlerBegin = getOffset(BeginSym, FuncBeginSym);
1266  MCSymbol *EndSym = EndSymbolMap[Clause.State];
1267  const MCExpr *HandlerEnd = getOffset(EndSym, FuncBeginSym);
1268 
1269  uint32_t Flags = 0;
1270  switch (Entry.HandlerType) {
1271  case ClrHandlerType::Catch:
1272  // Leaving bits 0-2 clear indicates catch.
1273  break;
1275  Flags |= 1;
1276  break;
1278  Flags |= 2;
1279  break;
1280  case ClrHandlerType::Fault:
1281  Flags |= 4;
1282  break;
1283  }
1284  if (Clause.EnclosingState != MinClauseMap[Clause.State]) {
1285  // This is a "duplicate" clause; the handler needs to be entered from a
1286  // frame above the one holding the invoke.
1287  assert(Clause.EnclosingState > MinClauseMap[Clause.State]);
1288  Flags |= 8;
1289  }
1290  OS.EmitIntValue(Flags, 4);
1291 
1292  // Write the clause start/end
1293  OS.EmitValue(ClauseBegin, 4);
1294  OS.EmitValue(ClauseEnd, 4);
1295 
1296  // Write out the handler start/end
1297  OS.EmitValue(HandlerBegin, 4);
1298  OS.EmitValue(HandlerEnd, 4);
1299 
1300  // Write out the type token or filter offset
1301  assert(Entry.HandlerType != ClrHandlerType::Filter && "NYI: filters");
1302  OS.EmitIntValue(Entry.TypeToken, 4);
1303  }
1304 }
detail::concat_range< ValueT, RangeTs... > concat(RangeTs &&... Ranges)
Concatenated range across two or more ranges.
Definition: STLExtras.h:946
MBBOrBasicBlock Handler
Definition: WinEHFuncInfo.h:82
const TargetLoweringObjectFile & getObjFileLowering() const
Return information about object file lowering.
Definition: AsmPrinter.cpp:206
Instances of this class represent a uniqued identifier for a section in the current translation unit...
Definition: MCSection.h:38
bool usesWindowsCFI() const
Definition: MCAsmInfo.h:583
SmallVector< WinEHHandlerType, 1 > HandlerArray
Definition: WinEHFuncInfo.h:76
GCNRegPressure max(const GCNRegPressure &P1, const GCNRegPressure &P2)
bool isCall(QueryType Type=AnyInBundle) const
Definition: MachineInstr.h:632
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:42
This class represents lattice values for constants.
Definition: AllocatorList.h:23
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:41
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:97
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:92
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:141
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:365
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:36
MBBOrBasicBlock Handler
Holds the __except or __finally basic block.
Definition: WinEHFuncInfo.h:57
void endModule() override
Emit all exception information that should come after the content.
Emits exception handling directives.
Definition: EHStreamer.h:30
Twine - A lightweight data structure for efficiently representing the concatenation of temporary valu...
Definition: Twine.h:80
bool isAArch64() const
Tests whether the target is AArch64 (little and big endian).
Definition: Triple.h:673
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:41
Base class for the full range of assembler expressions which are needed for parsing.
Definition: MCExpr.h:35
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:2090
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:49
Context object for machine code objects.
Definition: MCContext.h:62
virtual void AddComment(const Twine &T, bool EOL=true)
Add a textual comment.
Definition: MCStreamer.h:311
static const MCBinaryExpr * createSub(const MCExpr *LHS, const MCExpr *RHS, MCContext &Ctx)
Definition: MCExpr.h:545
MCSymbol * getFunctionBegin() const
Definition: AsmPrinter.h:208
virtual int getNonLocalFrameIndexReference(const MachineFunction &MF, int FI) const
getNonLocalFrameIndexReference - This method returns the offset used to reference a frame index locat...
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:701
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:265
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:123
void EmitValue(const MCExpr *Value, unsigned Size, SMLoc Loc=SMLoc())
Definition: MCStreamer.cpp:154
Similar to CxxUnwindMapEntry, but supports SEH filters.
Definition: WinEHFuncInfo.h:46
SmallVector< ClrEHUnwindMapEntry, 4 > ClrEHUnwindMap
Definition: WinEHFuncInfo.h:98
Streaming machine code generation interface.
Definition: MCStreamer.h:188
MCSymbol * createTempSymbol(bool CanBeUnnamed=true)
Create and return a new assembler temporary symbol with a unique but unspecified name.
Definition: MCContext.cpp:216
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.
union llvm::WinEHHandlerType::@194 CatchObj
The CatchObj starts out life as an LLVM alloca and is eventually turned frame index.
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:978
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:141
const Constant * stripPointerCasts() const
Definition: Constant.h:173
const MachineBasicBlock & front() const
size_t size() const
Definition: SmallVector.h:52
AsmPrinter * Asm
Target of directive emission.
Definition: EHStreamer.h:33
MBBOrBasicBlock Handler
Definition: WinEHFuncInfo.h:69
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:95
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:54
Iterator for intrusive lists based on ilist_node.
MCSymbol * getOrCreateLSDASymbol(StringRef FuncName)
Definition: MCContext.cpp:146
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:839
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:373
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:572
SmallVector< WinEHTryBlockMapEntry, 4 > TryBlockMap
Definition: WinEHFuncInfo.h:96
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:471
GlobalVariable * TypeDescriptor
Definition: WinEHFuncInfo.h:68
~WinException() override
bool operator!=(uint64_t V1, const APInt &V2)
Definition: APInt.h:1968
Representation of each machine instruction.
Definition: MachineInstr.h:63
const MachineFunction * getParent() const
Return the MachineFunction containing this basic block.
void emplace_back(ArgTypes &&... Args)
Definition: SmallVector.h:644
MCSymbol * getOrCreateSymbol(const Twine &Name)
Lookup the symbol inside with the specified Name.
Definition: MCContext.cpp:122
LLVM_NODISCARD bool empty() const
Definition: SmallVector.h:55
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:322
ClrHandlerType HandlerType
Definition: WinEHFuncInfo.h:87
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:134
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
MCSymbol * emitExceptionTable()
Emit landing pads and actions.
Definition: EHStreamer.cpp:349
MCSymbol * getMCSymbol() const
LLVM Value Representation.
Definition: Value.h:72
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:346
const DataLayout & getDataLayout() const
Return information about data layout.
Definition: AsmPrinter.cpp:210
IRTranslator LLVM IR MI
StringRef - Represent a constant reference to a string, i.e.
Definition: StringRef.h:48
bool operator==(uint64_t V1, const APInt &V2)
Definition: APInt.h:1966
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:288
const MachineOperand & getOperand(unsigned i) const
Definition: MachineInstr.h:413
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:163
static Expected< BitVector > scan(StringRef &S, StringRef Original)
Definition: GlobPattern.cpp:66
This file describes how to lower LLVM code to machine code.
A function that returns a base type.
Definition: COFF.h:261