LLVM  11.0.0git
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"
39 using namespace llvm;
40 
42  // MSVC's EH tables are always composed of 32-bit words. All known 64-bit
43  // platforms use an imagerel32 relocation to refer to symbols.
44  useImageRel32 = (A->getDataLayout().getPointerSizeInBits() == 64);
45  isAArch64 = Asm->TM.getTargetTriple().isAArch64();
46 }
47 
49 
50 /// endModule - Emit all exception information that should come after the
51 /// content.
53  auto &OS = *Asm->OutStreamer;
54  const Module *M = MMI->getModule();
55  for (const Function &F : *M)
56  if (F.hasFnAttribute("safeseh"))
57  OS.EmitCOFFSafeSEH(Asm->getSymbol(&F));
58 }
59 
61  shouldEmitMoves = shouldEmitPersonality = shouldEmitLSDA = false;
62 
63  // If any landing pads survive, we need an EH table.
64  bool hasLandingPads = !MF->getLandingPads().empty();
65  bool hasEHFunclets = MF->hasEHFunclets();
66 
67  const Function &F = MF->getFunction();
68 
69  shouldEmitMoves = Asm->needsSEHMoves() && MF->hasWinCFI();
70 
72  unsigned PerEncoding = TLOF.getPersonalityEncoding();
73 
75  const Function *PerFn = nullptr;
76  if (F.hasPersonalityFn()) {
78  Per = classifyEHPersonality(PerFn);
79  }
80 
81  bool forceEmitPersonality = F.hasPersonalityFn() &&
82  !isNoOpWithoutInvoke(Per) &&
84 
85  shouldEmitPersonality =
86  forceEmitPersonality || ((hasLandingPads || hasEHFunclets) &&
87  PerEncoding != dwarf::DW_EH_PE_omit && PerFn);
88 
89  unsigned LSDAEncoding = TLOF.getLSDAEncoding();
90  shouldEmitLSDA = shouldEmitPersonality &&
91  LSDAEncoding != dwarf::DW_EH_PE_omit;
92 
93  // If we're not using CFI, we don't want the CFI or the personality, but we
94  // might want EH tables if we had EH pads.
95  if (!Asm->MAI->usesWindowsCFI()) {
96  if (Per == EHPersonality::MSVC_X86SEH && !hasEHFunclets) {
97  // If this is 32-bit SEH and we don't have any funclets (really invokes),
98  // make sure we emit the parent offset label. Some unreferenced filter
99  // functions may still refer to it.
100  const WinEHFuncInfo &FuncInfo = *MF->getWinEHFuncInfo();
101  StringRef FLinkageName =
103  emitEHRegistrationOffsetLabel(FuncInfo, FLinkageName);
104  }
105  shouldEmitLSDA = hasEHFunclets;
106  shouldEmitPersonality = false;
107  return;
108  }
109 
111 }
112 
114  if (isAArch64 && CurrentFuncletEntry &&
115  (shouldEmitMoves || shouldEmitPersonality))
116  Asm->OutStreamer->EmitWinCFIFuncletOrFuncEnd();
117 }
118 
119 /// endFunction - Gather and emit post-function exception information.
120 ///
122  if (!shouldEmitPersonality && !shouldEmitMoves && !shouldEmitLSDA)
123  return;
124 
125  const Function &F = MF->getFunction();
127  if (F.hasPersonalityFn())
129 
130  // Get rid of any dead landing pads if we're not using funclets. In funclet
131  // schemes, the landing pad is not actually reachable. It only exists so
132  // that we can emit the right table data.
133  if (!isFuncletEHPersonality(Per)) {
134  MachineFunction *NonConstMF = const_cast<MachineFunction*>(MF);
135  NonConstMF->tidyLandingPads();
136  }
137 
138  endFuncletImpl();
139 
140  // endFunclet will emit the necessary .xdata tables for x64 SEH.
141  if (Per == EHPersonality::MSVC_Win64SEH && MF->hasEHFunclets())
142  return;
143 
144  if (shouldEmitPersonality || shouldEmitLSDA) {
145  Asm->OutStreamer->PushSection();
146 
147  // Just switch sections to the right xdata section.
148  MCSection *XData = Asm->OutStreamer->getAssociatedXDataSection(
149  Asm->OutStreamer->getCurrentSectionOnly());
150  Asm->OutStreamer->SwitchSection(XData);
151 
152  // Emit the tables appropriate to the personality function in use. If we
153  // don't recognize the personality, assume it uses an Itanium-style LSDA.
154  if (Per == EHPersonality::MSVC_Win64SEH)
155  emitCSpecificHandlerTable(MF);
156  else if (Per == EHPersonality::MSVC_X86SEH)
157  emitExceptHandlerTable(MF);
158  else if (Per == EHPersonality::MSVC_CXX)
159  emitCXXFrameHandler3Table(MF);
160  else if (Per == EHPersonality::CoreCLR)
161  emitCLRExceptionTable(MF);
162  else
164 
165  Asm->OutStreamer->PopSection();
166  }
167 }
168 
169 /// Retrieve the MCSymbol for a GlobalValue or MachineBasicBlock.
171  const MachineBasicBlock *MBB) {
172  if (!MBB)
173  return nullptr;
174 
175  assert(MBB->isEHFuncletEntry());
176 
177  // Give catches and cleanups a name based off of their parent function and
178  // their funclet entry block's number.
179  const MachineFunction *MF = MBB->getParent();
180  const Function &F = MF->getFunction();
182  MCContext &Ctx = MF->getContext();
183  StringRef HandlerPrefix = MBB->isCleanupFuncletEntry() ? "dtor" : "catch";
184  return Ctx.getOrCreateSymbol("?" + HandlerPrefix + "$" +
185  Twine(MBB->getNumber()) + "@?0?" +
186  FuncLinkageName + "@4HA");
187 }
188 
190  MCSymbol *Sym) {
191  CurrentFuncletEntry = &MBB;
192 
193  const Function &F = Asm->MF->getFunction();
194  // If a symbol was not provided for the funclet, invent one.
195  if (!Sym) {
196  Sym = getMCSymbolForMBB(Asm, &MBB);
197 
198  // Describe our funclet symbol as a function with internal linkage.
199  Asm->OutStreamer->BeginCOFFSymbolDef(Sym);
200  Asm->OutStreamer->EmitCOFFSymbolStorageClass(COFF::IMAGE_SYM_CLASS_STATIC);
201  Asm->OutStreamer->EmitCOFFSymbolType(COFF::IMAGE_SYM_DTYPE_FUNCTION
203  Asm->OutStreamer->EndCOFFSymbolDef();
204 
205  // We want our funclet's entry point to be aligned such that no nops will be
206  // present after the label.
208  &F);
209 
210  // Now that we've emitted the alignment directive, point at our funclet.
211  Asm->OutStreamer->emitLabel(Sym);
212  }
213 
214  // Mark 'Sym' as starting our funclet.
215  if (shouldEmitMoves || shouldEmitPersonality) {
216  CurrentFuncletTextSection = Asm->OutStreamer->getCurrentSectionOnly();
217  Asm->OutStreamer->EmitWinCFIStartProc(Sym);
218  }
219 
220  if (shouldEmitPersonality) {
222  const Function *PerFn = nullptr;
223 
224  // Determine which personality routine we are using for this funclet.
225  if (F.hasPersonalityFn())
226  PerFn = dyn_cast<Function>(F.getPersonalityFn()->stripPointerCasts());
227  const MCSymbol *PersHandlerSym =
228  TLOF.getCFIPersonalitySymbol(PerFn, Asm->TM, MMI);
229 
230  // Do not emit a .seh_handler directives for cleanup funclets.
231  // FIXME: This means cleanup funclets cannot handle exceptions. Given that
232  // Clang doesn't produce EH constructs inside cleanup funclets and LLVM's
233  // inliner doesn't allow inlining them, this isn't a major problem in
234  // practice.
235  if (!CurrentFuncletEntry->isCleanupFuncletEntry())
236  Asm->OutStreamer->EmitWinEHHandler(PersHandlerSym, true, true);
237  }
238 }
239 
241  if (isAArch64 && CurrentFuncletEntry &&
242  (shouldEmitMoves || shouldEmitPersonality)) {
243  Asm->OutStreamer->SwitchSection(CurrentFuncletTextSection);
244  Asm->OutStreamer->EmitWinCFIFuncletOrFuncEnd();
245  }
246  endFuncletImpl();
247 }
248 
249 void WinException::endFuncletImpl() {
250  // No funclet to process? Great, we have nothing to do.
251  if (!CurrentFuncletEntry)
252  return;
253 
254  const MachineFunction *MF = Asm->MF;
255  if (shouldEmitMoves || shouldEmitPersonality) {
256  const Function &F = MF->getFunction();
258  if (F.hasPersonalityFn())
260 
261  // On funclet exit, we emit a fake "function" end marker, so that the call
262  // to EmitWinEHHandlerData below can calculate the size of the funclet or
263  // function.
264  if (isAArch64) {
265  MCSection *XData = Asm->OutStreamer->getAssociatedXDataSection(
266  Asm->OutStreamer->getCurrentSectionOnly());
267  Asm->OutStreamer->SwitchSection(XData);
268  }
269 
270  // Emit an UNWIND_INFO struct describing the prologue.
271  Asm->OutStreamer->EmitWinEHHandlerData();
272 
273  if (Per == EHPersonality::MSVC_CXX && shouldEmitPersonality &&
274  !CurrentFuncletEntry->isCleanupFuncletEntry()) {
275  // If this is a C++ catch funclet (or the parent function),
276  // emit a reference to the LSDA for the parent function.
278  MCSymbol *FuncInfoXData = Asm->OutContext.getOrCreateSymbol(
279  Twine("$cppxdata$", FuncLinkageName));
280  Asm->OutStreamer->emitValue(create32bitRef(FuncInfoXData), 4);
281  } else if (Per == EHPersonality::MSVC_Win64SEH && MF->hasEHFunclets() &&
282  !CurrentFuncletEntry->isEHFuncletEntry()) {
283  // If this is the parent function in Win64 SEH, emit the LSDA immediately
284  // following .seh_handlerdata.
285  emitCSpecificHandlerTable(MF);
286  }
287 
288  // Switch back to the funclet start .text section now that we are done
289  // writing to .xdata, and emit an .seh_endproc directive to mark the end of
290  // the function.
291  Asm->OutStreamer->SwitchSection(CurrentFuncletTextSection);
292  Asm->OutStreamer->EmitWinCFIEndProc();
293  }
294 
295  // Let's make sure we don't try to end the same funclet twice.
296  CurrentFuncletEntry = nullptr;
297 }
298 
299 const MCExpr *WinException::create32bitRef(const MCSymbol *Value) {
300  if (!Value)
302  return MCSymbolRefExpr::create(Value, useImageRel32
305  Asm->OutContext);
306 }
307 
308 const MCExpr *WinException::create32bitRef(const GlobalValue *GV) {
309  if (!GV)
311  return create32bitRef(Asm->getSymbol(GV));
312 }
313 
314 const MCExpr *WinException::getLabel(const MCSymbol *Label) {
315  if (isAArch64)
317  Asm->OutContext);
318  return MCBinaryExpr::createAdd(create32bitRef(Label),
320  Asm->OutContext);
321 }
322 
323 const MCExpr *WinException::getOffset(const MCSymbol *OffsetOf,
324  const MCSymbol *OffsetFrom) {
328 }
329 
330 const MCExpr *WinException::getOffsetPlusOne(const MCSymbol *OffsetOf,
331  const MCSymbol *OffsetFrom) {
332  return MCBinaryExpr::createAdd(getOffset(OffsetOf, OffsetFrom),
334  Asm->OutContext);
335 }
336 
337 int WinException::getFrameIndexOffset(int FrameIndex,
338  const WinEHFuncInfo &FuncInfo) {
340  Register UnusedReg;
341  if (Asm->MAI->usesWindowsCFI()) {
342  int Offset =
344  /*IgnoreSPUpdates*/ true);
345  assert(UnusedReg ==
346  Asm->MF->getSubtarget()
349  return Offset;
350  }
351 
352  // For 32-bit, offsets should be relative to the end of the EH registration
353  // node. For 64-bit, it's relative to SP at the end of the prologue.
354  assert(FuncInfo.EHRegNodeEndOffset != INT_MAX);
355  int Offset = TFI.getFrameIndexReference(*Asm->MF, FrameIndex, UnusedReg);
356  Offset += FuncInfo.EHRegNodeEndOffset;
357  return Offset;
358 }
359 
360 namespace {
361 
362 /// Top-level state used to represent unwind to caller
363 const int NullState = -1;
364 
365 struct InvokeStateChange {
366  /// EH Label immediately after the last invoke in the previous state, or
367  /// nullptr if the previous state was the null state.
368  const MCSymbol *PreviousEndLabel;
369 
370  /// EH label immediately before the first invoke in the new state, or nullptr
371  /// if the new state is the null state.
372  const MCSymbol *NewStartLabel;
373 
374  /// State of the invoke following NewStartLabel, or NullState to indicate
375  /// the presence of calls which may unwind to caller.
376  int NewState;
377 };
378 
379 /// Iterator that reports all the invoke state changes in a range of machine
380 /// basic blocks. Changes to the null state are reported whenever a call that
381 /// may unwind to caller is encountered. The MBB range is expected to be an
382 /// entire function or funclet, and the start and end of the range are treated
383 /// as being in the NullState even if there's not an unwind-to-caller call
384 /// before the first invoke or after the last one (i.e., the first state change
385 /// reported is the first change to something other than NullState, and a
386 /// change back to NullState is always reported at the end of iteration).
387 class InvokeStateChangeIterator {
388  InvokeStateChangeIterator(const WinEHFuncInfo &EHInfo,
392  int BaseState)
393  : EHInfo(EHInfo), MFI(MFI), MFE(MFE), MBBI(MBBI), BaseState(BaseState) {
394  LastStateChange.PreviousEndLabel = nullptr;
395  LastStateChange.NewStartLabel = nullptr;
396  LastStateChange.NewState = BaseState;
397  scan();
398  }
399 
400 public:
402  range(const WinEHFuncInfo &EHInfo, MachineFunction::const_iterator Begin,
403  MachineFunction::const_iterator End, int BaseState = NullState) {
404  // Reject empty ranges to simplify bookkeeping by ensuring that we can get
405  // the end of the last block.
406  assert(Begin != End);
407  auto BlockBegin = Begin->begin();
408  auto BlockEnd = std::prev(End)->end();
409  return make_range(
410  InvokeStateChangeIterator(EHInfo, Begin, End, BlockBegin, BaseState),
411  InvokeStateChangeIterator(EHInfo, End, End, BlockEnd, BaseState));
412  }
413 
414  // Iterator methods.
415  bool operator==(const InvokeStateChangeIterator &O) const {
416  assert(BaseState == O.BaseState);
417  // Must be visiting same block.
418  if (MFI != O.MFI)
419  return false;
420  // Must be visiting same isntr.
421  if (MBBI != O.MBBI)
422  return false;
423  // At end of block/instr iteration, we can still have two distinct states:
424  // one to report the final EndLabel, and another indicating the end of the
425  // state change iteration. Check for CurrentEndLabel equality to
426  // distinguish these.
427  return CurrentEndLabel == O.CurrentEndLabel;
428  }
429 
430  bool operator!=(const InvokeStateChangeIterator &O) const {
431  return !operator==(O);
432  }
433  InvokeStateChange &operator*() { return LastStateChange; }
434  InvokeStateChange *operator->() { return &LastStateChange; }
435  InvokeStateChangeIterator &operator++() { return scan(); }
436 
437 private:
438  InvokeStateChangeIterator &scan();
439 
440  const WinEHFuncInfo &EHInfo;
441  const MCSymbol *CurrentEndLabel = nullptr;
445  InvokeStateChange LastStateChange;
446  bool VisitingInvoke = false;
447  int BaseState;
448 };
449 
450 } // end anonymous namespace
451 
452 InvokeStateChangeIterator &InvokeStateChangeIterator::scan() {
453  bool IsNewBlock = false;
454  for (; MFI != MFE; ++MFI, IsNewBlock = true) {
455  if (IsNewBlock)
456  MBBI = MFI->begin();
457  for (auto MBBE = MFI->end(); MBBI != MBBE; ++MBBI) {
458  const MachineInstr &MI = *MBBI;
459  if (!VisitingInvoke && LastStateChange.NewState != BaseState &&
461  // Indicate a change of state to the null state. We don't have
462  // start/end EH labels handy but the caller won't expect them for
463  // null state regions.
464  LastStateChange.PreviousEndLabel = CurrentEndLabel;
465  LastStateChange.NewStartLabel = nullptr;
466  LastStateChange.NewState = BaseState;
467  CurrentEndLabel = nullptr;
468  // Don't re-visit this instr on the next scan
469  ++MBBI;
470  return *this;
471  }
472 
473  // All other state changes are at EH labels before/after invokes.
474  if (!MI.isEHLabel())
475  continue;
476  MCSymbol *Label = MI.getOperand(0).getMCSymbol();
477  if (Label == CurrentEndLabel) {
478  VisitingInvoke = false;
479  continue;
480  }
481  auto InvokeMapIter = EHInfo.LabelToStateMap.find(Label);
482  // Ignore EH labels that aren't the ones inserted before an invoke
483  if (InvokeMapIter == EHInfo.LabelToStateMap.end())
484  continue;
485  auto &StateAndEnd = InvokeMapIter->second;
486  int NewState = StateAndEnd.first;
487  // Keep track of the fact that we're between EH start/end labels so
488  // we know not to treat the inoke we'll see as unwinding to caller.
489  VisitingInvoke = true;
490  if (NewState == LastStateChange.NewState) {
491  // The state isn't actually changing here. Record the new end and
492  // keep going.
493  CurrentEndLabel = StateAndEnd.second;
494  continue;
495  }
496  // Found a state change to report
497  LastStateChange.PreviousEndLabel = CurrentEndLabel;
498  LastStateChange.NewStartLabel = Label;
499  LastStateChange.NewState = NewState;
500  // Start keeping track of the new current end
501  CurrentEndLabel = StateAndEnd.second;
502  // Don't re-visit this instr on the next scan
503  ++MBBI;
504  return *this;
505  }
506  }
507  // Iteration hit the end of the block range.
508  if (LastStateChange.NewState != BaseState) {
509  // Report the end of the last new state
510  LastStateChange.PreviousEndLabel = CurrentEndLabel;
511  LastStateChange.NewStartLabel = nullptr;
512  LastStateChange.NewState = BaseState;
513  // Leave CurrentEndLabel non-null to distinguish this state from end.
514  assert(CurrentEndLabel != nullptr);
515  return *this;
516  }
517  // We've reported all state changes and hit the end state.
518  CurrentEndLabel = nullptr;
519  return *this;
520 }
521 
522 /// Emit the language-specific data that __C_specific_handler expects. This
523 /// handler lives in the x64 Microsoft C runtime and allows catching or cleaning
524 /// up after faults with __try, __except, and __finally. The typeinfo values
525 /// are not really RTTI data, but pointers to filter functions that return an
526 /// integer (1, 0, or -1) indicating how to handle the exception. For __finally
527 /// blocks and other cleanups, the landing pad label is zero, and the filter
528 /// function is actually a cleanup handler with the same prototype. A catch-all
529 /// entry is modeled with a null filter function field and a non-zero landing
530 /// pad label.
531 ///
532 /// Possible filter function return values:
533 /// EXCEPTION_EXECUTE_HANDLER (1):
534 /// Jump to the landing pad label after cleanups.
535 /// EXCEPTION_CONTINUE_SEARCH (0):
536 /// Continue searching this table or continue unwinding.
537 /// EXCEPTION_CONTINUE_EXECUTION (-1):
538 /// Resume execution at the trapping PC.
539 ///
540 /// Inferred table structure:
541 /// struct Table {
542 /// int NumEntries;
543 /// struct Entry {
544 /// imagerel32 LabelStart;
545 /// imagerel32 LabelEnd;
546 /// imagerel32 FilterOrFinally; // One means catch-all.
547 /// imagerel32 LabelLPad; // Zero means __finally.
548 /// } Entries[NumEntries];
549 /// };
550 void WinException::emitCSpecificHandlerTable(const MachineFunction *MF) {
551  auto &OS = *Asm->OutStreamer;
552  MCContext &Ctx = Asm->OutContext;
553  const WinEHFuncInfo &FuncInfo = *MF->getWinEHFuncInfo();
554 
555  bool VerboseAsm = OS.isVerboseAsm();
556  auto AddComment = [&](const Twine &Comment) {
557  if (VerboseAsm)
558  OS.AddComment(Comment);
559  };
560 
561  if (!isAArch64) {
562  // Emit a label assignment with the SEH frame offset so we can use it for
563  // llvm.eh.recoverfp.
564  StringRef FLinkageName =
566  MCSymbol *ParentFrameOffset =
567  Ctx.getOrCreateParentFrameOffsetSymbol(FLinkageName);
568  const MCExpr *MCOffset =
570  Asm->OutStreamer->emitAssignment(ParentFrameOffset, MCOffset);
571  }
572 
573  // Use the assembler to compute the number of table entries through label
574  // difference and division.
575  MCSymbol *TableBegin =
576  Ctx.createTempSymbol("lsda_begin", /*AlwaysAddSuffix=*/true);
577  MCSymbol *TableEnd =
578  Ctx.createTempSymbol("lsda_end", /*AlwaysAddSuffix=*/true);
579  const MCExpr *LabelDiff = getOffset(TableEnd, TableBegin);
580  const MCExpr *EntrySize = MCConstantExpr::create(16, Ctx);
581  const MCExpr *EntryCount = MCBinaryExpr::createDiv(LabelDiff, EntrySize, Ctx);
582  AddComment("Number of call sites");
583  OS.emitValue(EntryCount, 4);
584 
585  OS.emitLabel(TableBegin);
586 
587  // Iterate over all the invoke try ranges. Unlike MSVC, LLVM currently only
588  // models exceptions from invokes. LLVM also allows arbitrary reordering of
589  // the code, so our tables end up looking a bit different. Rather than
590  // trying to match MSVC's tables exactly, we emit a denormalized table. For
591  // each range of invokes in the same state, we emit table entries for all
592  // the actions that would be taken in that state. This means our tables are
593  // slightly bigger, which is OK.
594  const MCSymbol *LastStartLabel = nullptr;
595  int LastEHState = -1;
596  // Break out before we enter into a finally funclet.
597  // FIXME: We need to emit separate EH tables for cleanups.
599  MachineFunction::const_iterator Stop = std::next(MF->begin());
600  while (Stop != End && !Stop->isEHFuncletEntry())
601  ++Stop;
602  for (const auto &StateChange :
603  InvokeStateChangeIterator::range(FuncInfo, MF->begin(), Stop)) {
604  // Emit all the actions for the state we just transitioned out of
605  // if it was not the null state
606  if (LastEHState != -1)
607  emitSEHActionsForRange(FuncInfo, LastStartLabel,
608  StateChange.PreviousEndLabel, LastEHState);
609  LastStartLabel = StateChange.NewStartLabel;
610  LastEHState = StateChange.NewState;
611  }
612 
613  OS.emitLabel(TableEnd);
614 }
615 
616 void WinException::emitSEHActionsForRange(const WinEHFuncInfo &FuncInfo,
617  const MCSymbol *BeginLabel,
618  const MCSymbol *EndLabel, int State) {
619  auto &OS = *Asm->OutStreamer;
620  MCContext &Ctx = Asm->OutContext;
621  bool VerboseAsm = OS.isVerboseAsm();
622  auto AddComment = [&](const Twine &Comment) {
623  if (VerboseAsm)
624  OS.AddComment(Comment);
625  };
626 
627  assert(BeginLabel && EndLabel);
628  while (State != -1) {
629  const SEHUnwindMapEntry &UME = FuncInfo.SEHUnwindMap[State];
630  const MCExpr *FilterOrFinally;
631  const MCExpr *ExceptOrNull;
632  auto *Handler = UME.Handler.get<MachineBasicBlock *>();
633  if (UME.IsFinally) {
634  FilterOrFinally = create32bitRef(getMCSymbolForMBB(Asm, Handler));
635  ExceptOrNull = MCConstantExpr::create(0, Ctx);
636  } else {
637  // For an except, the filter can be 1 (catch-all) or a function
638  // label.
639  FilterOrFinally = UME.Filter ? create32bitRef(UME.Filter)
640  : MCConstantExpr::create(1, Ctx);
641  ExceptOrNull = create32bitRef(Handler->getSymbol());
642  }
643 
644  AddComment("LabelStart");
645  OS.emitValue(getLabel(BeginLabel), 4);
646  AddComment("LabelEnd");
647  OS.emitValue(getLabel(EndLabel), 4);
648  AddComment(UME.IsFinally ? "FinallyFunclet" : UME.Filter ? "FilterFunction"
649  : "CatchAll");
650  OS.emitValue(FilterOrFinally, 4);
651  AddComment(UME.IsFinally ? "Null" : "ExceptionHandler");
652  OS.emitValue(ExceptOrNull, 4);
653 
654  assert(UME.ToState < State && "states should decrease");
655  State = UME.ToState;
656  }
657 }
658 
659 void WinException::emitCXXFrameHandler3Table(const MachineFunction *MF) {
660  const Function &F = MF->getFunction();
661  auto &OS = *Asm->OutStreamer;
662  const WinEHFuncInfo &FuncInfo = *MF->getWinEHFuncInfo();
663 
665 
667  MCSymbol *FuncInfoXData = nullptr;
668  if (shouldEmitPersonality) {
669  // If we're 64-bit, emit a pointer to the C++ EH data, and build a map from
670  // IPs to state numbers.
671  FuncInfoXData =
672  Asm->OutContext.getOrCreateSymbol(Twine("$cppxdata$", FuncLinkageName));
673  computeIP2StateTable(MF, FuncInfo, IPToStateTable);
674  } else {
675  FuncInfoXData = Asm->OutContext.getOrCreateLSDASymbol(FuncLinkageName);
676  }
677 
678  int UnwindHelpOffset = 0;
679  if (Asm->MAI->usesWindowsCFI())
680  UnwindHelpOffset =
681  getFrameIndexOffset(FuncInfo.UnwindHelpFrameIdx, FuncInfo);
682 
683  MCSymbol *UnwindMapXData = nullptr;
684  MCSymbol *TryBlockMapXData = nullptr;
685  MCSymbol *IPToStateXData = nullptr;
686  if (!FuncInfo.CxxUnwindMap.empty())
687  UnwindMapXData = Asm->OutContext.getOrCreateSymbol(
688  Twine("$stateUnwindMap$", FuncLinkageName));
689  if (!FuncInfo.TryBlockMap.empty())
690  TryBlockMapXData =
691  Asm->OutContext.getOrCreateSymbol(Twine("$tryMap$", FuncLinkageName));
692  if (!IPToStateTable.empty())
693  IPToStateXData =
694  Asm->OutContext.getOrCreateSymbol(Twine("$ip2state$", FuncLinkageName));
695 
696  bool VerboseAsm = OS.isVerboseAsm();
697  auto AddComment = [&](const Twine &Comment) {
698  if (VerboseAsm)
699  OS.AddComment(Comment);
700  };
701 
702  // FuncInfo {
703  // uint32_t MagicNumber
704  // int32_t MaxState;
705  // UnwindMapEntry *UnwindMap;
706  // uint32_t NumTryBlocks;
707  // TryBlockMapEntry *TryBlockMap;
708  // uint32_t IPMapEntries; // always 0 for x86
709  // IPToStateMapEntry *IPToStateMap; // always 0 for x86
710  // uint32_t UnwindHelp; // non-x86 only
711  // ESTypeList *ESTypeList;
712  // int32_t EHFlags;
713  // }
714  // EHFlags & 1 -> Synchronous exceptions only, no async exceptions.
715  // EHFlags & 2 -> ???
716  // EHFlags & 4 -> The function is noexcept(true), unwinding can't continue.
717  OS.emitValueToAlignment(4);
718  OS.emitLabel(FuncInfoXData);
719 
720  AddComment("MagicNumber");
721  OS.emitInt32(0x19930522);
722 
723  AddComment("MaxState");
724  OS.emitInt32(FuncInfo.CxxUnwindMap.size());
725 
726  AddComment("UnwindMap");
727  OS.emitValue(create32bitRef(UnwindMapXData), 4);
728 
729  AddComment("NumTryBlocks");
730  OS.emitInt32(FuncInfo.TryBlockMap.size());
731 
732  AddComment("TryBlockMap");
733  OS.emitValue(create32bitRef(TryBlockMapXData), 4);
734 
735  AddComment("IPMapEntries");
736  OS.emitInt32(IPToStateTable.size());
737 
738  AddComment("IPToStateXData");
739  OS.emitValue(create32bitRef(IPToStateXData), 4);
740 
741  if (Asm->MAI->usesWindowsCFI()) {
742  AddComment("UnwindHelp");
743  OS.emitInt32(UnwindHelpOffset);
744  }
745 
746  AddComment("ESTypeList");
747  OS.emitInt32(0);
748 
749  AddComment("EHFlags");
750  OS.emitInt32(1);
751 
752  // UnwindMapEntry {
753  // int32_t ToState;
754  // void (*Action)();
755  // };
756  if (UnwindMapXData) {
757  OS.emitLabel(UnwindMapXData);
758  for (const CxxUnwindMapEntry &UME : FuncInfo.CxxUnwindMap) {
759  MCSymbol *CleanupSym =
761  AddComment("ToState");
762  OS.emitInt32(UME.ToState);
763 
764  AddComment("Action");
765  OS.emitValue(create32bitRef(CleanupSym), 4);
766  }
767  }
768 
769  // TryBlockMap {
770  // int32_t TryLow;
771  // int32_t TryHigh;
772  // int32_t CatchHigh;
773  // int32_t NumCatches;
774  // HandlerType *HandlerArray;
775  // };
776  if (TryBlockMapXData) {
777  OS.emitLabel(TryBlockMapXData);
778  SmallVector<MCSymbol *, 1> HandlerMaps;
779  for (size_t I = 0, E = FuncInfo.TryBlockMap.size(); I != E; ++I) {
780  const WinEHTryBlockMapEntry &TBME = FuncInfo.TryBlockMap[I];
781 
782  MCSymbol *HandlerMapXData = nullptr;
783  if (!TBME.HandlerArray.empty())
784  HandlerMapXData =
785  Asm->OutContext.getOrCreateSymbol(Twine("$handlerMap$")
786  .concat(Twine(I))
787  .concat("$")
788  .concat(FuncLinkageName));
789  HandlerMaps.push_back(HandlerMapXData);
790 
791  // TBMEs should form intervals.
792  assert(0 <= TBME.TryLow && "bad trymap interval");
793  assert(TBME.TryLow <= TBME.TryHigh && "bad trymap interval");
794  assert(TBME.TryHigh < TBME.CatchHigh && "bad trymap interval");
795  assert(TBME.CatchHigh < int(FuncInfo.CxxUnwindMap.size()) &&
796  "bad trymap interval");
797 
798  AddComment("TryLow");
799  OS.emitInt32(TBME.TryLow);
800 
801  AddComment("TryHigh");
802  OS.emitInt32(TBME.TryHigh);
803 
804  AddComment("CatchHigh");
805  OS.emitInt32(TBME.CatchHigh);
806 
807  AddComment("NumCatches");
808  OS.emitInt32(TBME.HandlerArray.size());
809 
810  AddComment("HandlerArray");
811  OS.emitValue(create32bitRef(HandlerMapXData), 4);
812  }
813 
814  // All funclets use the same parent frame offset currently.
815  unsigned ParentFrameOffset = 0;
816  if (shouldEmitPersonality) {
818  ParentFrameOffset = TFI->getWinEHParentFrameOffset(*MF);
819  }
820 
821  for (size_t I = 0, E = FuncInfo.TryBlockMap.size(); I != E; ++I) {
822  const WinEHTryBlockMapEntry &TBME = FuncInfo.TryBlockMap[I];
823  MCSymbol *HandlerMapXData = HandlerMaps[I];
824  if (!HandlerMapXData)
825  continue;
826  // HandlerType {
827  // int32_t Adjectives;
828  // TypeDescriptor *Type;
829  // int32_t CatchObjOffset;
830  // void (*Handler)();
831  // int32_t ParentFrameOffset; // x64 and AArch64 only
832  // };
833  OS.emitLabel(HandlerMapXData);
834  for (const WinEHHandlerType &HT : TBME.HandlerArray) {
835  // Get the frame escape label with the offset of the catch object. If
836  // the index is INT_MAX, then there is no catch object, and we should
837  // emit an offset of zero, indicating that no copy will occur.
838  const MCExpr *FrameAllocOffsetRef = nullptr;
839  if (HT.CatchObj.FrameIndex != INT_MAX) {
840  int Offset = getFrameIndexOffset(HT.CatchObj.FrameIndex, FuncInfo);
841  assert(Offset != 0 && "Illegal offset for catch object!");
842  FrameAllocOffsetRef = MCConstantExpr::create(Offset, Asm->OutContext);
843  } else {
844  FrameAllocOffsetRef = MCConstantExpr::create(0, Asm->OutContext);
845  }
846 
847  MCSymbol *HandlerSym =
849 
850  AddComment("Adjectives");
851  OS.emitInt32(HT.Adjectives);
852 
853  AddComment("Type");
854  OS.emitValue(create32bitRef(HT.TypeDescriptor), 4);
855 
856  AddComment("CatchObjOffset");
857  OS.emitValue(FrameAllocOffsetRef, 4);
858 
859  AddComment("Handler");
860  OS.emitValue(create32bitRef(HandlerSym), 4);
861 
862  if (shouldEmitPersonality) {
863  AddComment("ParentFrameOffset");
864  OS.emitInt32(ParentFrameOffset);
865  }
866  }
867  }
868  }
869 
870  // IPToStateMapEntry {
871  // void *IP;
872  // int32_t State;
873  // };
874  if (IPToStateXData) {
875  OS.emitLabel(IPToStateXData);
876  for (auto &IPStatePair : IPToStateTable) {
877  AddComment("IP");
878  OS.emitValue(IPStatePair.first, 4);
879  AddComment("ToState");
880  OS.emitInt32(IPStatePair.second);
881  }
882  }
883 }
884 
885 void WinException::computeIP2StateTable(
886  const MachineFunction *MF, const WinEHFuncInfo &FuncInfo,
887  SmallVectorImpl<std::pair<const MCExpr *, int>> &IPToStateTable) {
888 
889  for (MachineFunction::const_iterator FuncletStart = MF->begin(),
890  FuncletEnd = MF->begin(),
891  End = MF->end();
892  FuncletStart != End; FuncletStart = FuncletEnd) {
893  // Find the end of the funclet
894  while (++FuncletEnd != End) {
895  if (FuncletEnd->isEHFuncletEntry()) {
896  break;
897  }
898  }
899 
900  // Don't emit ip2state entries for cleanup funclets. Any interesting
901  // exceptional actions in cleanups must be handled in a separate IR
902  // function.
903  if (FuncletStart->isCleanupFuncletEntry())
904  continue;
905 
906  MCSymbol *StartLabel;
907  int BaseState;
908  if (FuncletStart == MF->begin()) {
909  BaseState = NullState;
910  StartLabel = Asm->getFunctionBegin();
911  } else {
912  auto *FuncletPad =
913  cast<FuncletPadInst>(FuncletStart->getBasicBlock()->getFirstNonPHI());
914  assert(FuncInfo.FuncletBaseStateMap.count(FuncletPad) != 0);
915  BaseState = FuncInfo.FuncletBaseStateMap.find(FuncletPad)->second;
916  StartLabel = getMCSymbolForMBB(Asm, &*FuncletStart);
917  }
918  assert(StartLabel && "need local function start label");
919  IPToStateTable.push_back(
920  std::make_pair(create32bitRef(StartLabel), BaseState));
921 
922  for (const auto &StateChange : InvokeStateChangeIterator::range(
923  FuncInfo, FuncletStart, FuncletEnd, BaseState)) {
924  // Compute the label to report as the start of this entry; use the EH
925  // start label for the invoke if we have one, otherwise (this is a call
926  // which may unwind to our caller and does not have an EH start label, so)
927  // use the previous end label.
928  const MCSymbol *ChangeLabel = StateChange.NewStartLabel;
929  if (!ChangeLabel)
930  ChangeLabel = StateChange.PreviousEndLabel;
931  // Emit an entry indicating that PCs after 'Label' have this EH state.
932  IPToStateTable.push_back(
933  std::make_pair(getLabel(ChangeLabel), StateChange.NewState));
934  // FIXME: assert that NewState is between CatchLow and CatchHigh.
935  }
936  }
937 }
938 
939 void WinException::emitEHRegistrationOffsetLabel(const WinEHFuncInfo &FuncInfo,
940  StringRef FLinkageName) {
941  // Outlined helpers called by the EH runtime need to know the offset of the EH
942  // registration in order to recover the parent frame pointer. Now that we know
943  // we've code generated the parent, we can emit the label assignment that
944  // those helpers use to get the offset of the registration node.
945 
946  // Compute the parent frame offset. The EHRegNodeFrameIndex will be invalid if
947  // after optimization all the invokes were eliminated. We still need to emit
948  // the parent frame offset label, but it should be garbage and should never be
949  // used.
950  int64_t Offset = 0;
951  int FI = FuncInfo.EHRegNodeFrameIndex;
952  if (FI != INT_MAX) {
954  Offset = TFI->getNonLocalFrameIndexReference(*Asm->MF, FI);
955  }
956 
957  MCContext &Ctx = Asm->OutContext;
958  MCSymbol *ParentFrameOffset =
959  Ctx.getOrCreateParentFrameOffsetSymbol(FLinkageName);
960  Asm->OutStreamer->emitAssignment(ParentFrameOffset,
961  MCConstantExpr::create(Offset, Ctx));
962 }
963 
964 /// Emit the language-specific data that _except_handler3 and 4 expect. This is
965 /// functionally equivalent to the __C_specific_handler table, except it is
966 /// indexed by state number instead of IP.
967 void WinException::emitExceptHandlerTable(const MachineFunction *MF) {
968  MCStreamer &OS = *Asm->OutStreamer;
969  const Function &F = MF->getFunction();
971 
972  bool VerboseAsm = OS.isVerboseAsm();
973  auto AddComment = [&](const Twine &Comment) {
974  if (VerboseAsm)
975  OS.AddComment(Comment);
976  };
977 
978  const WinEHFuncInfo &FuncInfo = *MF->getWinEHFuncInfo();
979  emitEHRegistrationOffsetLabel(FuncInfo, FLinkageName);
980 
981  // Emit the __ehtable label that we use for llvm.x86.seh.lsda.
982  MCSymbol *LSDALabel = Asm->OutContext.getOrCreateLSDASymbol(FLinkageName);
983  OS.emitValueToAlignment(4);
984  OS.emitLabel(LSDALabel);
985 
986  const auto *Per = cast<Function>(F.getPersonalityFn()->stripPointerCasts());
987  StringRef PerName = Per->getName();
988  int BaseState = -1;
989  if (PerName == "_except_handler4") {
990  // The LSDA for _except_handler4 starts with this struct, followed by the
991  // scope table:
992  //
993  // struct EH4ScopeTable {
994  // int32_t GSCookieOffset;
995  // int32_t GSCookieXOROffset;
996  // int32_t EHCookieOffset;
997  // int32_t EHCookieXOROffset;
998  // ScopeTableEntry ScopeRecord[];
999  // };
1000  //
1001  // Offsets are %ebp relative.
1002  //
1003  // The GS cookie is present only if the function needs stack protection.
1004  // GSCookieOffset = -2 means that GS cookie is not used.
1005  //
1006  // The EH cookie is always present.
1007  //
1008  // Check is done the following way:
1009  // (ebp+CookieXOROffset) ^ [ebp+CookieOffset] == _security_cookie
1010 
1011  // Retrieve the Guard Stack slot.
1012  int GSCookieOffset = -2;
1013  const MachineFrameInfo &MFI = MF->getFrameInfo();
1014  if (MFI.hasStackProtectorIndex()) {
1015  Register UnusedReg;
1016  const TargetFrameLowering *TFI = MF->getSubtarget().getFrameLowering();
1017  int SSPIdx = MFI.getStackProtectorIndex();
1018  GSCookieOffset = TFI->getFrameIndexReference(*MF, SSPIdx, UnusedReg);
1019  }
1020 
1021  // Retrieve the EH Guard slot.
1022  // TODO(etienneb): Get rid of this value and change it for and assertion.
1023  int EHCookieOffset = 9999;
1024  if (FuncInfo.EHGuardFrameIndex != INT_MAX) {
1025  Register UnusedReg;
1026  const TargetFrameLowering *TFI = MF->getSubtarget().getFrameLowering();
1027  int EHGuardIdx = FuncInfo.EHGuardFrameIndex;
1028  EHCookieOffset = TFI->getFrameIndexReference(*MF, EHGuardIdx, UnusedReg);
1029  }
1030 
1031  AddComment("GSCookieOffset");
1032  OS.emitInt32(GSCookieOffset);
1033  AddComment("GSCookieXOROffset");
1034  OS.emitInt32(0);
1035  AddComment("EHCookieOffset");
1036  OS.emitInt32(EHCookieOffset);
1037  AddComment("EHCookieXOROffset");
1038  OS.emitInt32(0);
1039  BaseState = -2;
1040  }
1041 
1042  assert(!FuncInfo.SEHUnwindMap.empty());
1043  for (const SEHUnwindMapEntry &UME : FuncInfo.SEHUnwindMap) {
1044  auto *Handler = UME.Handler.get<MachineBasicBlock *>();
1045  const MCSymbol *ExceptOrFinally =
1046  UME.IsFinally ? getMCSymbolForMBB(Asm, Handler) : Handler->getSymbol();
1047  // -1 is usually the base state for "unwind to caller", but for
1048  // _except_handler4 it's -2. Do that replacement here if necessary.
1049  int ToState = UME.ToState == -1 ? BaseState : UME.ToState;
1050  AddComment("ToState");
1051  OS.emitInt32(ToState);
1052  AddComment(UME.IsFinally ? "Null" : "FilterFunction");
1053  OS.emitValue(create32bitRef(UME.Filter), 4);
1054  AddComment(UME.IsFinally ? "FinallyFunclet" : "ExceptionHandler");
1055  OS.emitValue(create32bitRef(ExceptOrFinally), 4);
1056  }
1057 }
1058 
1059 static int getTryRank(const WinEHFuncInfo &FuncInfo, int State) {
1060  int Rank = 0;
1061  while (State != -1) {
1062  ++Rank;
1063  State = FuncInfo.ClrEHUnwindMap[State].TryParentState;
1064  }
1065  return Rank;
1066 }
1067 
1068 static int getTryAncestor(const WinEHFuncInfo &FuncInfo, int Left, int Right) {
1069  int LeftRank = getTryRank(FuncInfo, Left);
1070  int RightRank = getTryRank(FuncInfo, Right);
1071 
1072  while (LeftRank < RightRank) {
1073  Right = FuncInfo.ClrEHUnwindMap[Right].TryParentState;
1074  --RightRank;
1075  }
1076 
1077  while (RightRank < LeftRank) {
1078  Left = FuncInfo.ClrEHUnwindMap[Left].TryParentState;
1079  --LeftRank;
1080  }
1081 
1082  while (Left != Right) {
1083  Left = FuncInfo.ClrEHUnwindMap[Left].TryParentState;
1084  Right = FuncInfo.ClrEHUnwindMap[Right].TryParentState;
1085  }
1086 
1087  return Left;
1088 }
1089 
1090 void WinException::emitCLRExceptionTable(const MachineFunction *MF) {
1091  // CLR EH "states" are really just IDs that identify handlers/funclets;
1092  // states, handlers, and funclets all have 1:1 mappings between them, and a
1093  // handler/funclet's "state" is its index in the ClrEHUnwindMap.
1094  MCStreamer &OS = *Asm->OutStreamer;
1095  const WinEHFuncInfo &FuncInfo = *MF->getWinEHFuncInfo();
1096  MCSymbol *FuncBeginSym = Asm->getFunctionBegin();
1097  MCSymbol *FuncEndSym = Asm->getFunctionEnd();
1098 
1099  // A ClrClause describes a protected region.
1100  struct ClrClause {
1101  const MCSymbol *StartLabel; // Start of protected region
1102  const MCSymbol *EndLabel; // End of protected region
1103  int State; // Index of handler protecting the protected region
1104  int EnclosingState; // Index of funclet enclosing the protected region
1105  };
1106  SmallVector<ClrClause, 8> Clauses;
1107 
1108  // Build a map from handler MBBs to their corresponding states (i.e. their
1109  // indices in the ClrEHUnwindMap).
1110  int NumStates = FuncInfo.ClrEHUnwindMap.size();
1111  assert(NumStates > 0 && "Don't need exception table!");
1113  for (int State = 0; State < NumStates; ++State) {
1114  MachineBasicBlock *HandlerBlock =
1115  FuncInfo.ClrEHUnwindMap[State].Handler.get<MachineBasicBlock *>();
1116  HandlerStates[HandlerBlock] = State;
1117  // Use this loop through all handlers to verify our assumption (used in
1118  // the MinEnclosingState computation) that enclosing funclets have lower
1119  // state numbers than their enclosed funclets.
1120  assert(FuncInfo.ClrEHUnwindMap[State].HandlerParentState < State &&
1121  "ill-formed state numbering");
1122  }
1123  // Map the main function to the NullState.
1124  HandlerStates[&MF->front()] = NullState;
1125 
1126  // Write out a sentinel indicating the end of the standard (Windows) xdata
1127  // and the start of the additional (CLR) info.
1128  OS.emitInt32(0xffffffff);
1129  // Write out the number of funclets
1130  OS.emitInt32(NumStates);
1131 
1132  // Walk the machine blocks/instrs, computing and emitting a few things:
1133  // 1. Emit a list of the offsets to each handler entry, in lexical order.
1134  // 2. Compute a map (EndSymbolMap) from each funclet to the symbol at its end.
1135  // 3. Compute the list of ClrClauses, in the required order (inner before
1136  // outer, earlier before later; the order by which a forward scan with
1137  // early termination will find the innermost enclosing clause covering
1138  // a given address).
1139  // 4. A map (MinClauseMap) from each handler index to the index of the
1140  // outermost funclet/function which contains a try clause targeting the
1141  // key handler. This will be used to determine IsDuplicate-ness when
1142  // emitting ClrClauses. The NullState value is used to indicate that the
1143  // top-level function contains a try clause targeting the key handler.
1144  // HandlerStack is a stack of (PendingStartLabel, PendingState) pairs for
1145  // try regions we entered before entering the PendingState try but which
1146  // we haven't yet exited.
1148  // EndSymbolMap and MinClauseMap are maps described above.
1149  std::unique_ptr<MCSymbol *[]> EndSymbolMap(new MCSymbol *[NumStates]);
1150  SmallVector<int, 4> MinClauseMap((size_t)NumStates, NumStates);
1151 
1152  // Visit the root function and each funclet.
1153  for (MachineFunction::const_iterator FuncletStart = MF->begin(),
1154  FuncletEnd = MF->begin(),
1155  End = MF->end();
1156  FuncletStart != End; FuncletStart = FuncletEnd) {
1157  int FuncletState = HandlerStates[&*FuncletStart];
1158  // Find the end of the funclet
1159  MCSymbol *EndSymbol = FuncEndSym;
1160  while (++FuncletEnd != End) {
1161  if (FuncletEnd->isEHFuncletEntry()) {
1162  EndSymbol = getMCSymbolForMBB(Asm, &*FuncletEnd);
1163  break;
1164  }
1165  }
1166  // Emit the function/funclet end and, if this is a funclet (and not the
1167  // root function), record it in the EndSymbolMap.
1168  OS.emitValue(getOffset(EndSymbol, FuncBeginSym), 4);
1169  if (FuncletState != NullState) {
1170  // Record the end of the handler.
1171  EndSymbolMap[FuncletState] = EndSymbol;
1172  }
1173 
1174  // Walk the state changes in this function/funclet and compute its clauses.
1175  // Funclets always start in the null state.
1176  const MCSymbol *CurrentStartLabel = nullptr;
1177  int CurrentState = NullState;
1178  assert(HandlerStack.empty());
1179  for (const auto &StateChange :
1180  InvokeStateChangeIterator::range(FuncInfo, FuncletStart, FuncletEnd)) {
1181  // Close any try regions we're not still under
1182  int StillPendingState =
1183  getTryAncestor(FuncInfo, CurrentState, StateChange.NewState);
1184  while (CurrentState != StillPendingState) {
1185  assert(CurrentState != NullState &&
1186  "Failed to find still-pending state!");
1187  // Close the pending clause
1188  Clauses.push_back({CurrentStartLabel, StateChange.PreviousEndLabel,
1189  CurrentState, FuncletState});
1190  // Now the next-outer try region is current
1191  CurrentState = FuncInfo.ClrEHUnwindMap[CurrentState].TryParentState;
1192  // Pop the new start label from the handler stack if we've exited all
1193  // inner try regions of the corresponding try region.
1194  if (HandlerStack.back().second == CurrentState)
1195  CurrentStartLabel = HandlerStack.pop_back_val().first;
1196  }
1197 
1198  if (StateChange.NewState != CurrentState) {
1199  // For each clause we're starting, update the MinClauseMap so we can
1200  // know which is the topmost funclet containing a clause targeting
1201  // it.
1202  for (int EnteredState = StateChange.NewState;
1203  EnteredState != CurrentState;
1204  EnteredState =
1205  FuncInfo.ClrEHUnwindMap[EnteredState].TryParentState) {
1206  int &MinEnclosingState = MinClauseMap[EnteredState];
1207  if (FuncletState < MinEnclosingState)
1208  MinEnclosingState = FuncletState;
1209  }
1210  // Save the previous current start/label on the stack and update to
1211  // the newly-current start/state.
1212  HandlerStack.emplace_back(CurrentStartLabel, CurrentState);
1213  CurrentStartLabel = StateChange.NewStartLabel;
1214  CurrentState = StateChange.NewState;
1215  }
1216  }
1217  assert(HandlerStack.empty());
1218  }
1219 
1220  // Now emit the clause info, starting with the number of clauses.
1221  OS.emitInt32(Clauses.size());
1222  for (ClrClause &Clause : Clauses) {
1223  // Emit a CORINFO_EH_CLAUSE :
1224  /*
1225  struct CORINFO_EH_CLAUSE
1226  {
1227  CORINFO_EH_CLAUSE_FLAGS Flags; // actually a CorExceptionFlag
1228  DWORD TryOffset;
1229  DWORD TryLength; // actually TryEndOffset
1230  DWORD HandlerOffset;
1231  DWORD HandlerLength; // actually HandlerEndOffset
1232  union
1233  {
1234  DWORD ClassToken; // use for catch clauses
1235  DWORD FilterOffset; // use for filter clauses
1236  };
1237  };
1238 
1239  enum CORINFO_EH_CLAUSE_FLAGS
1240  {
1241  CORINFO_EH_CLAUSE_NONE = 0,
1242  CORINFO_EH_CLAUSE_FILTER = 0x0001, // This clause is for a filter
1243  CORINFO_EH_CLAUSE_FINALLY = 0x0002, // This clause is a finally clause
1244  CORINFO_EH_CLAUSE_FAULT = 0x0004, // This clause is a fault clause
1245  };
1246  typedef enum CorExceptionFlag
1247  {
1248  COR_ILEXCEPTION_CLAUSE_NONE,
1249  COR_ILEXCEPTION_CLAUSE_FILTER = 0x0001, // This is a filter clause
1250  COR_ILEXCEPTION_CLAUSE_FINALLY = 0x0002, // This is a finally clause
1251  COR_ILEXCEPTION_CLAUSE_FAULT = 0x0004, // This is a fault clause
1252  COR_ILEXCEPTION_CLAUSE_DUPLICATED = 0x0008, // duplicated clause. This
1253  // clause was duplicated
1254  // to a funclet which was
1255  // pulled out of line
1256  } CorExceptionFlag;
1257  */
1258  // Add 1 to the start/end of the EH clause; the IP associated with a
1259  // call when the runtime does its scan is the IP of the next instruction
1260  // (the one to which control will return after the call), so we need
1261  // to add 1 to the end of the clause to cover that offset. We also add
1262  // 1 to the start of the clause to make sure that the ranges reported
1263  // for all clauses are disjoint. Note that we'll need some additional
1264  // logic when machine traps are supported, since in that case the IP
1265  // that the runtime uses is the offset of the faulting instruction
1266  // itself; if such an instruction immediately follows a call but the
1267  // two belong to different clauses, we'll need to insert a nop between
1268  // them so the runtime can distinguish the point to which the call will
1269  // return from the point at which the fault occurs.
1270 
1271  const MCExpr *ClauseBegin =
1272  getOffsetPlusOne(Clause.StartLabel, FuncBeginSym);
1273  const MCExpr *ClauseEnd = getOffsetPlusOne(Clause.EndLabel, FuncBeginSym);
1274 
1275  const ClrEHUnwindMapEntry &Entry = FuncInfo.ClrEHUnwindMap[Clause.State];
1276  MachineBasicBlock *HandlerBlock = Entry.Handler.get<MachineBasicBlock *>();
1277  MCSymbol *BeginSym = getMCSymbolForMBB(Asm, HandlerBlock);
1278  const MCExpr *HandlerBegin = getOffset(BeginSym, FuncBeginSym);
1279  MCSymbol *EndSym = EndSymbolMap[Clause.State];
1280  const MCExpr *HandlerEnd = getOffset(EndSym, FuncBeginSym);
1281 
1282  uint32_t Flags = 0;
1283  switch (Entry.HandlerType) {
1284  case ClrHandlerType::Catch:
1285  // Leaving bits 0-2 clear indicates catch.
1286  break;
1288  Flags |= 1;
1289  break;
1291  Flags |= 2;
1292  break;
1293  case ClrHandlerType::Fault:
1294  Flags |= 4;
1295  break;
1296  }
1297  if (Clause.EnclosingState != MinClauseMap[Clause.State]) {
1298  // This is a "duplicate" clause; the handler needs to be entered from a
1299  // frame above the one holding the invoke.
1300  assert(Clause.EnclosingState > MinClauseMap[Clause.State]);
1301  Flags |= 8;
1302  }
1303  OS.emitInt32(Flags);
1304 
1305  // Write the clause start/end
1306  OS.emitValue(ClauseBegin, 4);
1307  OS.emitValue(ClauseEnd, 4);
1308 
1309  // Write out the handler start/end
1310  OS.emitValue(HandlerBegin, 4);
1311  OS.emitValue(HandlerEnd, 4);
1312 
1313  // Write out the type token or filter offset
1314  assert(Entry.HandlerType != ClrHandlerType::Filter && "NYI: filters");
1315  OS.emitInt32(Entry.TypeToken);
1316  }
1317 }
detail::concat_range< ValueT, RangeTs... > concat(RangeTs &&... Ranges)
Concatenated range across two or more ranges.
Definition: STLExtras.h:1023
MBBOrBasicBlock Handler
Definition: WinEHFuncInfo.h:82
virtual void emitLabel(MCSymbol *Symbol, SMLoc Loc=SMLoc())
Emit a label for Symbol into the current section.
Definition: MCStreamer.cpp:395
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
reference emplace_back(ArgTypes &&... Args)
Definition: SmallVector.h:687
bool usesWindowsCFI() const
Definition: MCAsmInfo.h:631
SmallVector< WinEHHandlerType, 1 > HandlerArray
Definition: WinEHFuncInfo.h:76
LLVM_NODISCARD std::enable_if_t< !is_simple_type< Y >::value, typename cast_retty< X, const Y >::ret_type > dyn_cast(const Y &Val)
Definition: Casting.h:334
bool isCall(QueryType Type=AnyInBundle) const
Definition: MachineInstr.h:760
std::unique_ptr< MCStreamer > OutStreamer
This is the MCStreamer object for the file we are generating.
Definition: AsmPrinter.h:96
static int getTryAncestor(const WinEHFuncInfo &FuncInfo, int Left, int Right)
static const MCSymbolRefExpr * create(const MCSymbol *Symbol, MCContext &Ctx)
Definition: MCExpr.h:369
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
Align getAlignment() const
getAlignment - Return the alignment of the function.
A Module instance is used to store all the information related to an LLVM module. ...
Definition: Module.h:67
bool hasStackProtectorIndex() const
SmallVector< SEHUnwindMapEntry, 4 > SEHUnwindMap
Definition: WinEHFuncInfo.h:97
MCContext & OutContext
This is the context for the output file that we are streaming.
Definition: AsmPrinter.h:91
union llvm::WinEHHandlerType::@212 CatchObj
The CatchObj starts out life as an LLVM alloca and is eventually turned frame index.
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:152
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:396
F(f)
MachineFunction * MF
The current machine function.
Definition: AsmPrinter.h:99
T get() const
Returns the value of the specified pointer type.
Definition: PointerUnion.h:194
Function & getFunction()
Return the LLVM function that this machine code represents.
MachineBasicBlock & MBB
MachineModuleInfo * MMI
Collected machine module information.
Definition: EHStreamer.h:36
MBBOrBasicBlock Handler
Holds the __except or __finally basic block.
Definition: WinEHFuncInfo.h:57
T dyn_cast() const
Returns the current pointer if it is of the specified pointer type, otherwise returns null...
Definition: PointerUnion.h:201
void endModule() override
Emit all exception information that should come after the content.
Emits exception handling directives.
Definition: EHStreamer.h:30
static const MCConstantExpr * create(int64_t Value, MCContext &Ctx, bool PrintInHex=false, unsigned SizeInBytes=0)
Definition: MCExpr.cpp:186
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:705
static const MCBinaryExpr * createDiv(const MCExpr *LHS, const MCExpr *RHS, MCContext &Ctx)
Definition: MCExpr.h:519
This class consists of common code factored out of the SmallVector class to reduce code duplication b...
Definition: APFloat.h:43
Base class for the full range of assembler expressions which are needed for parsing.
Definition: MCExpr.h:35
void emitInt32(uint64_t Value)
Definition: MCStreamer.h:676
The MachineFrameInfo class represents an abstract stack frame until prolog/epilog code is inserted...
Align getAlignment() const
Return alignment of the basic block.
APInt operator*(APInt a, uint64_t RHS)
Definition: APInt.h:2151
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:66
virtual void AddComment(const Twine &T, bool EOL=true)
Add a textual comment.
Definition: MCStreamer.h:327
static const MCBinaryExpr * createSub(const MCExpr *LHS, const MCExpr *RHS, MCContext &Ctx)
Definition: MCExpr.h:594
MCSymbol * getFunctionBegin() const
Definition: AsmPrinter.h:231
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:757
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:509
void endFunclet() override
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:196
MCSymbol * createTempSymbol(bool CanBeUnnamed=true)
Create and return a new assembler temporary symbol with a unique but unspecified name.
Definition: MCContext.cpp:239
MCSymbol * CurrentFnSym
The symbol for the current function.
Definition: AsmPrinter.h:118
const MCAsmInfo * MAI
Target Asm Printer information.
Definition: AsmPrinter.h:87
virtual int getFrameIndexReference(const MachineFunction &MF, int FI, Register &FrameReg) const
getFrameIndexReference - This method should return the base register and offset used to reference a f...
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)
TargetMachine & TM
Target machine description.
Definition: AsmPrinter.h:84
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:81
void endFunction(const MachineFunction *) override
Gather and emit post-function exception information.
virtual int getFrameIndexReferencePreferSP(const MachineFunction &MF, int FI, Register &FrameReg, bool IgnoreSPUpdates) const
Same as getFrameIndexReference, except that the stack pointer (as opposed to the frame pointer) will ...
EHPersonality classifyEHPersonality(const Value *Pers)
See if the given exception handling personality function is one that we understand.
bool isEHLabel() const
const Triple & getTargetTriple() const
const Constant * stripPointerCasts() const
Definition: Constant.h:191
const MachineBasicBlock & front() const
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.
Align max(MaybeAlign Lhs, Align Rhs)
Definition: Alignment.h:350
MCSymbol * getOrCreateLSDASymbol(StringRef FuncName)
Definition: MCContext.cpp:157
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:437
This is a &#39;vector&#39; (really, a variable-sized array), optimized for the case when the array is small...
Definition: SmallVector.h:883
Module.h This file contains the declarations for the Module class.
void markFunctionEnd() override
Information about stack frame layout on the target.
LLVM_NODISCARD T pop_back_val()
Definition: SmallVector.h:420
const WinEHFuncInfo * getWinEHFuncInfo() const
getWinEHFuncInfo - Return information about how the current function uses Windows exception handling...
MCSymbol * getFunctionEnd() const
Definition: AsmPrinter.h:232
bool needsUnwindTableEntry() const
True if this function needs an unwind table.
Definition: Function.h:619
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:482
GlobalVariable * TypeDescriptor
Definition: WinEHFuncInfo.h:68
~WinException() override
bool operator!=(uint64_t V1, const APInt &V2)
Definition: APInt.h:2029
Representation of each machine instruction.
Definition: MachineInstr.h:62
const MachineFunction * getParent() const
Return the MachineFunction containing this basic block.
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.
MCSymbol * getOrCreateSymbol(const Twine &Name)
Lookup the symbol inside with the specified Name.
Definition: MCContext.cpp:133
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:270
#define I(x, y, z)
Definition: MD5.cpp:59
virtual const TargetFrameLowering * getFrameLowering() const
void emitValue(const MCExpr *Value, unsigned Size, SMLoc Loc=SMLoc())
Definition: MCStreamer.cpp:160
ClrHandlerType HandlerType
Definition: WinEHFuncInfo.h:87
const Module * getModule() const
static int getTryRank(const WinEHFuncInfo &FuncInfo, int State)
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:74
Constant * getPersonalityFn() const
Get the personality function associated with this function.
Definition: Function.cpp:1512
unsigned getStackPointerRegisterToSaveRestore() const
If a physical register, this specifies the register that llvm.savestack/llvm.restorestack should save...
void emitAlignment(Align Alignment, const GlobalObject *GV=nullptr) const
Emit an alignment directive to the specified power of two boundary.
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:57
bool operator==(uint64_t V1, const APInt &V2)
Definition: APInt.h:2027
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:304
const MachineOperand & getOperand(unsigned i) const
Definition: MachineInstr.h:466
bool isNoOpWithoutInvoke(EHPersonality Pers)
Return true if this personality may be safely removed if there are no invoke instructions remaining i...
static Expected< BitVector > scan(StringRef &S, StringRef Original)
Definition: GlobPattern.cpp:67
MachineBasicBlock MachineBasicBlock::iterator MBBI
Wrapper class representing virtual and physical registers.
Definition: Register.h:19
This file describes how to lower LLVM code to machine code.
A function that returns a base type.
Definition: COFF.h:261