LLVM  8.0.0svn
EHStreamer.cpp
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1 //===- CodeGen/AsmPrinter/EHStreamer.cpp - Exception Directive Streamer ---===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file contains support for writing exception info into assembly files.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "EHStreamer.h"
15 #include "llvm/ADT/SmallVector.h"
16 #include "llvm/ADT/Twine.h"
23 #include "llvm/IR/DataLayout.h"
24 #include "llvm/IR/Function.h"
25 #include "llvm/MC/MCAsmInfo.h"
26 #include "llvm/MC/MCContext.h"
27 #include "llvm/MC/MCStreamer.h"
28 #include "llvm/MC/MCSymbol.h"
30 #include "llvm/Support/Casting.h"
31 #include "llvm/Support/LEB128.h"
33 #include <algorithm>
34 #include <cassert>
35 #include <cstdint>
36 #include <vector>
37 
38 using namespace llvm;
39 
40 EHStreamer::EHStreamer(AsmPrinter *A) : Asm(A), MMI(Asm->MMI) {}
41 
42 EHStreamer::~EHStreamer() = default;
43 
44 /// How many leading type ids two landing pads have in common.
46  const LandingPadInfo *R) {
47  const std::vector<int> &LIds = L->TypeIds, &RIds = R->TypeIds;
48  unsigned LSize = LIds.size(), RSize = RIds.size();
49  unsigned MinSize = LSize < RSize ? LSize : RSize;
50  unsigned Count = 0;
51 
52  for (; Count != MinSize; ++Count)
53  if (LIds[Count] != RIds[Count])
54  return Count;
55 
56  return Count;
57 }
58 
59 /// Compute the actions table and gather the first action index for each landing
60 /// pad site.
62  const SmallVectorImpl<const LandingPadInfo *> &LandingPads,
64  SmallVectorImpl<unsigned> &FirstActions) {
65  // The action table follows the call-site table in the LSDA. The individual
66  // records are of two types:
67  //
68  // * Catch clause
69  // * Exception specification
70  //
71  // The two record kinds have the same format, with only small differences.
72  // They are distinguished by the "switch value" field: Catch clauses
73  // (TypeInfos) have strictly positive switch values, and exception
74  // specifications (FilterIds) have strictly negative switch values. Value 0
75  // indicates a catch-all clause.
76  //
77  // Negative type IDs index into FilterIds. Positive type IDs index into
78  // TypeInfos. The value written for a positive type ID is just the type ID
79  // itself. For a negative type ID, however, the value written is the
80  // (negative) byte offset of the corresponding FilterIds entry. The byte
81  // offset is usually equal to the type ID (because the FilterIds entries are
82  // written using a variable width encoding, which outputs one byte per entry
83  // as long as the value written is not too large) but can differ. This kind
84  // of complication does not occur for positive type IDs because type infos are
85  // output using a fixed width encoding. FilterOffsets[i] holds the byte
86  // offset corresponding to FilterIds[i].
87 
88  const std::vector<unsigned> &FilterIds = Asm->MF->getFilterIds();
89  SmallVector<int, 16> FilterOffsets;
90  FilterOffsets.reserve(FilterIds.size());
91  int Offset = -1;
92 
93  for (std::vector<unsigned>::const_iterator
94  I = FilterIds.begin(), E = FilterIds.end(); I != E; ++I) {
95  FilterOffsets.push_back(Offset);
96  Offset -= getULEB128Size(*I);
97  }
98 
99  FirstActions.reserve(LandingPads.size());
100 
101  int FirstAction = 0;
102  unsigned SizeActions = 0; // Total size of all action entries for a function
103  const LandingPadInfo *PrevLPI = nullptr;
104 
106  I = LandingPads.begin(), E = LandingPads.end(); I != E; ++I) {
107  const LandingPadInfo *LPI = *I;
108  const std::vector<int> &TypeIds = LPI->TypeIds;
109  unsigned NumShared = PrevLPI ? sharedTypeIDs(LPI, PrevLPI) : 0;
110  unsigned SizeSiteActions = 0; // Total size of all entries for a landingpad
111 
112  if (NumShared < TypeIds.size()) {
113  // Size of one action entry (typeid + next action)
114  unsigned SizeActionEntry = 0;
115  unsigned PrevAction = (unsigned)-1;
116 
117  if (NumShared) {
118  unsigned SizePrevIds = PrevLPI->TypeIds.size();
119  assert(Actions.size());
120  PrevAction = Actions.size() - 1;
121  SizeActionEntry = getSLEB128Size(Actions[PrevAction].NextAction) +
122  getSLEB128Size(Actions[PrevAction].ValueForTypeID);
123 
124  for (unsigned j = NumShared; j != SizePrevIds; ++j) {
125  assert(PrevAction != (unsigned)-1 && "PrevAction is invalid!");
126  SizeActionEntry -= getSLEB128Size(Actions[PrevAction].ValueForTypeID);
127  SizeActionEntry += -Actions[PrevAction].NextAction;
128  PrevAction = Actions[PrevAction].Previous;
129  }
130  }
131 
132  // Compute the actions.
133  for (unsigned J = NumShared, M = TypeIds.size(); J != M; ++J) {
134  int TypeID = TypeIds[J];
135  assert(-1 - TypeID < (int)FilterOffsets.size() && "Unknown filter id!");
136  int ValueForTypeID =
137  isFilterEHSelector(TypeID) ? FilterOffsets[-1 - TypeID] : TypeID;
138  unsigned SizeTypeID = getSLEB128Size(ValueForTypeID);
139 
140  int NextAction = SizeActionEntry ? -(SizeActionEntry + SizeTypeID) : 0;
141  SizeActionEntry = SizeTypeID + getSLEB128Size(NextAction);
142  SizeSiteActions += SizeActionEntry;
143 
144  ActionEntry Action = { ValueForTypeID, NextAction, PrevAction };
145  Actions.push_back(Action);
146  PrevAction = Actions.size() - 1;
147  }
148 
149  // Record the first action of the landing pad site.
150  FirstAction = SizeActions + SizeSiteActions - SizeActionEntry + 1;
151  } // else identical - re-use previous FirstAction
152 
153  // Information used when creating the call-site table. The action record
154  // field of the call site record is the offset of the first associated
155  // action record, relative to the start of the actions table. This value is
156  // biased by 1 (1 indicating the start of the actions table), and 0
157  // indicates that there are no actions.
158  FirstActions.push_back(FirstAction);
159 
160  // Compute this sites contribution to size.
161  SizeActions += SizeSiteActions;
162 
163  PrevLPI = LPI;
164  }
165 }
166 
167 /// Return `true' if this is a call to a function marked `nounwind'. Return
168 /// `false' otherwise.
170  assert(MI->isCall() && "This should be a call instruction!");
171 
172  bool MarkedNoUnwind = false;
173  bool SawFunc = false;
174 
175  for (unsigned I = 0, E = MI->getNumOperands(); I != E; ++I) {
176  const MachineOperand &MO = MI->getOperand(I);
177 
178  if (!MO.isGlobal()) continue;
179 
180  const Function *F = dyn_cast<Function>(MO.getGlobal());
181  if (!F) continue;
182 
183  if (SawFunc) {
184  // Be conservative. If we have more than one function operand for this
185  // call, then we can't make the assumption that it's the callee and
186  // not a parameter to the call.
187  //
188  // FIXME: Determine if there's a way to say that `F' is the callee or
189  // parameter.
190  MarkedNoUnwind = false;
191  break;
192  }
193 
194  MarkedNoUnwind = F->doesNotThrow();
195  SawFunc = true;
196  }
197 
198  return MarkedNoUnwind;
199 }
200 
202  const SmallVectorImpl<const LandingPadInfo *> &LandingPads,
203  RangeMapType &PadMap) {
204  // Invokes and nounwind calls have entries in PadMap (due to being bracketed
205  // by try-range labels when lowered). Ordinary calls do not, so appropriate
206  // try-ranges for them need be deduced so we can put them in the LSDA.
207  for (unsigned i = 0, N = LandingPads.size(); i != N; ++i) {
208  const LandingPadInfo *LandingPad = LandingPads[i];
209  for (unsigned j = 0, E = LandingPad->BeginLabels.size(); j != E; ++j) {
210  MCSymbol *BeginLabel = LandingPad->BeginLabels[j];
211  assert(!PadMap.count(BeginLabel) && "Duplicate landing pad labels!");
212  PadRange P = { i, j };
213  PadMap[BeginLabel] = P;
214  }
215  }
216 }
217 
218 /// Compute the call-site table. The entry for an invoke has a try-range
219 /// containing the call, a non-zero landing pad, and an appropriate action. The
220 /// entry for an ordinary call has a try-range containing the call and zero for
221 /// the landing pad and the action. Calls marked 'nounwind' have no entry and
222 /// must not be contained in the try-range of any entry - they form gaps in the
223 /// table. Entries must be ordered by try-range address.
224 void EHStreamer::
226  const SmallVectorImpl<const LandingPadInfo *> &LandingPads,
227  const SmallVectorImpl<unsigned> &FirstActions) {
228  RangeMapType PadMap;
229  computePadMap(LandingPads, PadMap);
230 
231  // The end label of the previous invoke or nounwind try-range.
232  MCSymbol *LastLabel = nullptr;
233 
234  // Whether there is a potentially throwing instruction (currently this means
235  // an ordinary call) between the end of the previous try-range and now.
236  bool SawPotentiallyThrowing = false;
237 
238  // Whether the last CallSite entry was for an invoke.
239  bool PreviousIsInvoke = false;
240 
242 
243  // Visit all instructions in order of address.
244  for (const auto &MBB : *Asm->MF) {
245  for (const auto &MI : MBB) {
246  if (!MI.isEHLabel()) {
247  if (MI.isCall())
248  SawPotentiallyThrowing |= !callToNoUnwindFunction(&MI);
249  continue;
250  }
251 
252  // End of the previous try-range?
253  MCSymbol *BeginLabel = MI.getOperand(0).getMCSymbol();
254  if (BeginLabel == LastLabel)
255  SawPotentiallyThrowing = false;
256 
257  // Beginning of a new try-range?
258  RangeMapType::const_iterator L = PadMap.find(BeginLabel);
259  if (L == PadMap.end())
260  // Nope, it was just some random label.
261  continue;
262 
263  const PadRange &P = L->second;
264  const LandingPadInfo *LandingPad = LandingPads[P.PadIndex];
265  assert(BeginLabel == LandingPad->BeginLabels[P.RangeIndex] &&
266  "Inconsistent landing pad map!");
267 
268  // For Dwarf exception handling (SjLj handling doesn't use this). If some
269  // instruction between the previous try-range and this one may throw,
270  // create a call-site entry with no landing pad for the region between the
271  // try-ranges.
272  if (SawPotentiallyThrowing && Asm->MAI->usesCFIForEH()) {
273  CallSiteEntry Site = { LastLabel, BeginLabel, nullptr, 0 };
274  CallSites.push_back(Site);
275  PreviousIsInvoke = false;
276  }
277 
278  LastLabel = LandingPad->EndLabels[P.RangeIndex];
279  assert(BeginLabel && LastLabel && "Invalid landing pad!");
280 
281  if (!LandingPad->LandingPadLabel) {
282  // Create a gap.
283  PreviousIsInvoke = false;
284  } else {
285  // This try-range is for an invoke.
286  CallSiteEntry Site = {
287  BeginLabel,
288  LastLabel,
289  LandingPad,
290  FirstActions[P.PadIndex]
291  };
292 
293  // Try to merge with the previous call-site. SJLJ doesn't do this
294  if (PreviousIsInvoke && !IsSJLJ) {
295  CallSiteEntry &Prev = CallSites.back();
296  if (Site.LPad == Prev.LPad && Site.Action == Prev.Action) {
297  // Extend the range of the previous entry.
298  Prev.EndLabel = Site.EndLabel;
299  continue;
300  }
301  }
302 
303  // Otherwise, create a new call-site.
304  if (!IsSJLJ)
305  CallSites.push_back(Site);
306  else {
307  // SjLj EH must maintain the call sites in the order assigned
308  // to them by the SjLjPrepare pass.
309  unsigned SiteNo = Asm->MF->getCallSiteBeginLabel(BeginLabel);
310  if (CallSites.size() < SiteNo)
311  CallSites.resize(SiteNo);
312  CallSites[SiteNo - 1] = Site;
313  }
314  PreviousIsInvoke = true;
315  }
316  }
317  }
318 
319  // If some instruction between the previous try-range and the end of the
320  // function may throw, create a call-site entry with no landing pad for the
321  // region following the try-range.
322  if (SawPotentiallyThrowing && !IsSJLJ) {
323  CallSiteEntry Site = { LastLabel, nullptr, nullptr, 0 };
324  CallSites.push_back(Site);
325  }
326 }
327 
328 /// Emit landing pads and actions.
329 ///
330 /// The general organization of the table is complex, but the basic concepts are
331 /// easy. First there is a header which describes the location and organization
332 /// of the three components that follow.
333 ///
334 /// 1. The landing pad site information describes the range of code covered by
335 /// the try. In our case it's an accumulation of the ranges covered by the
336 /// invokes in the try. There is also a reference to the landing pad that
337 /// handles the exception once processed. Finally an index into the actions
338 /// table.
339 /// 2. The action table, in our case, is composed of pairs of type IDs and next
340 /// action offset. Starting with the action index from the landing pad
341 /// site, each type ID is checked for a match to the current exception. If
342 /// it matches then the exception and type id are passed on to the landing
343 /// pad. Otherwise the next action is looked up. This chain is terminated
344 /// with a next action of zero. If no type id is found then the frame is
345 /// unwound and handling continues.
346 /// 3. Type ID table contains references to all the C++ typeinfo for all
347 /// catches in the function. This tables is reverse indexed base 1.
349  const MachineFunction *MF = Asm->MF;
350  const std::vector<const GlobalValue *> &TypeInfos = MF->getTypeInfos();
351  const std::vector<unsigned> &FilterIds = MF->getFilterIds();
352  const std::vector<LandingPadInfo> &PadInfos = MF->getLandingPads();
353 
354  // Sort the landing pads in order of their type ids. This is used to fold
355  // duplicate actions.
357  LandingPads.reserve(PadInfos.size());
358 
359  for (unsigned i = 0, N = PadInfos.size(); i != N; ++i)
360  LandingPads.push_back(&PadInfos[i]);
361 
362  // Order landing pads lexicographically by type id.
363  llvm::sort(LandingPads, [](const LandingPadInfo *L, const LandingPadInfo *R) {
364  return L->TypeIds < R->TypeIds;
365  });
366 
367  // Compute the actions table and gather the first action index for each
368  // landing pad site.
370  SmallVector<unsigned, 64> FirstActions;
371  computeActionsTable(LandingPads, Actions, FirstActions);
372 
373  // Compute the call-site table.
375  computeCallSiteTable(CallSites, LandingPads, FirstActions);
376 
378  unsigned CallSiteEncoding =
380  bool HaveTTData = !TypeInfos.empty() || !FilterIds.empty();
381 
382  // Type infos.
383  MCSection *LSDASection = Asm->getObjFileLowering().getLSDASection();
384  unsigned TTypeEncoding;
385 
386  if (!HaveTTData) {
387  // If there is no TypeInfo, then we just explicitly say that we're omitting
388  // that bit.
389  TTypeEncoding = dwarf::DW_EH_PE_omit;
390  } else {
391  // Okay, we have actual filters or typeinfos to emit. As such, we need to
392  // pick a type encoding for them. We're about to emit a list of pointers to
393  // typeinfo objects at the end of the LSDA. However, unless we're in static
394  // mode, this reference will require a relocation by the dynamic linker.
395  //
396  // Because of this, we have a couple of options:
397  //
398  // 1) If we are in -static mode, we can always use an absolute reference
399  // from the LSDA, because the static linker will resolve it.
400  //
401  // 2) Otherwise, if the LSDA section is writable, we can output the direct
402  // reference to the typeinfo and allow the dynamic linker to relocate
403  // it. Since it is in a writable section, the dynamic linker won't
404  // have a problem.
405  //
406  // 3) Finally, if we're in PIC mode and the LDSA section isn't writable,
407  // we need to use some form of indirection. For example, on Darwin,
408  // we can output a statically-relocatable reference to a dyld stub. The
409  // offset to the stub is constant, but the contents are in a section
410  // that is updated by the dynamic linker. This is easy enough, but we
411  // need to tell the personality function of the unwinder to indirect
412  // through the dyld stub.
413  //
414  // FIXME: When (3) is actually implemented, we'll have to emit the stubs
415  // somewhere. This predicate should be moved to a shared location that is
416  // in target-independent code.
417  //
418  TTypeEncoding = Asm->getObjFileLowering().getTTypeEncoding();
419  }
420 
421  // Begin the exception table.
422  // Sometimes we want not to emit the data into separate section (e.g. ARM
423  // EHABI). In this case LSDASection will be NULL.
424  if (LSDASection)
425  Asm->OutStreamer->SwitchSection(LSDASection);
426  Asm->EmitAlignment(2);
427 
428  // Emit the LSDA.
429  MCSymbol *GCCETSym =
430  Asm->OutContext.getOrCreateSymbol(Twine("GCC_except_table")+
432  Asm->OutStreamer->EmitLabel(GCCETSym);
433  Asm->OutStreamer->EmitLabel(Asm->getCurExceptionSym());
434 
435  // Emit the LSDA header.
437  Asm->EmitEncodingByte(TTypeEncoding, "@TType");
438 
439  MCSymbol *TTBaseLabel = nullptr;
440  if (HaveTTData) {
441  // N.B.: There is a dependency loop between the size of the TTBase uleb128
442  // here and the amount of padding before the aligned type table. The
443  // assembler must sometimes pad this uleb128 or insert extra padding before
444  // the type table. See PR35809 or GNU as bug 4029.
445  MCSymbol *TTBaseRefLabel = Asm->createTempSymbol("ttbaseref");
446  TTBaseLabel = Asm->createTempSymbol("ttbase");
447  Asm->EmitLabelDifferenceAsULEB128(TTBaseLabel, TTBaseRefLabel);
448  Asm->OutStreamer->EmitLabel(TTBaseRefLabel);
449  }
450 
451  bool VerboseAsm = Asm->OutStreamer->isVerboseAsm();
452 
453  // Emit the landing pad call site table.
454  MCSymbol *CstBeginLabel = Asm->createTempSymbol("cst_begin");
455  MCSymbol *CstEndLabel = Asm->createTempSymbol("cst_end");
456  Asm->EmitEncodingByte(CallSiteEncoding, "Call site");
457  Asm->EmitLabelDifferenceAsULEB128(CstEndLabel, CstBeginLabel);
458  Asm->OutStreamer->EmitLabel(CstBeginLabel);
459 
460  // SjLj Exception handling
461  if (IsSJLJ) {
462  unsigned idx = 0;
464  I = CallSites.begin(), E = CallSites.end(); I != E; ++I, ++idx) {
465  const CallSiteEntry &S = *I;
466 
467  // Index of the call site entry.
468  if (VerboseAsm) {
469  Asm->OutStreamer->AddComment(">> Call Site " + Twine(idx) + " <<");
470  Asm->OutStreamer->AddComment(" On exception at call site "+Twine(idx));
471  }
472  Asm->EmitULEB128(idx);
473 
474  // Offset of the first associated action record, relative to the start of
475  // the action table. This value is biased by 1 (1 indicates the start of
476  // the action table), and 0 indicates that there are no actions.
477  if (VerboseAsm) {
478  if (S.Action == 0)
479  Asm->OutStreamer->AddComment(" Action: cleanup");
480  else
481  Asm->OutStreamer->AddComment(" Action: " +
482  Twine((S.Action - 1) / 2 + 1));
483  }
484  Asm->EmitULEB128(S.Action);
485  }
486  } else {
487  // Itanium LSDA exception handling
488 
489  // The call-site table is a list of all call sites that may throw an
490  // exception (including C++ 'throw' statements) in the procedure
491  // fragment. It immediately follows the LSDA header. Each entry indicates,
492  // for a given call, the first corresponding action record and corresponding
493  // landing pad.
494  //
495  // The table begins with the number of bytes, stored as an LEB128
496  // compressed, unsigned integer. The records immediately follow the record
497  // count. They are sorted in increasing call-site address. Each record
498  // indicates:
499  //
500  // * The position of the call-site.
501  // * The position of the landing pad.
502  // * The first action record for that call site.
503  //
504  // A missing entry in the call-site table indicates that a call is not
505  // supposed to throw.
506 
507  unsigned Entry = 0;
509  I = CallSites.begin(), E = CallSites.end(); I != E; ++I) {
510  const CallSiteEntry &S = *I;
511 
512  MCSymbol *EHFuncBeginSym = Asm->getFunctionBegin();
513 
514  MCSymbol *BeginLabel = S.BeginLabel;
515  if (!BeginLabel)
516  BeginLabel = EHFuncBeginSym;
517  MCSymbol *EndLabel = S.EndLabel;
518  if (!EndLabel)
519  EndLabel = Asm->getFunctionEnd();
520 
521  // Offset of the call site relative to the start of the procedure.
522  if (VerboseAsm)
523  Asm->OutStreamer->AddComment(">> Call Site " + Twine(++Entry) + " <<");
524  Asm->EmitLabelDifferenceAsULEB128(BeginLabel, EHFuncBeginSym);
525  if (VerboseAsm)
526  Asm->OutStreamer->AddComment(Twine(" Call between ") +
527  BeginLabel->getName() + " and " +
528  EndLabel->getName());
529  Asm->EmitLabelDifferenceAsULEB128(EndLabel, BeginLabel);
530 
531  // Offset of the landing pad relative to the start of the procedure.
532  if (!S.LPad) {
533  if (VerboseAsm)
534  Asm->OutStreamer->AddComment(" has no landing pad");
535  Asm->EmitULEB128(0);
536  } else {
537  if (VerboseAsm)
538  Asm->OutStreamer->AddComment(Twine(" jumps to ") +
541  EHFuncBeginSym);
542  }
543 
544  // Offset of the first associated action record, relative to the start of
545  // the action table. This value is biased by 1 (1 indicates the start of
546  // the action table), and 0 indicates that there are no actions.
547  if (VerboseAsm) {
548  if (S.Action == 0)
549  Asm->OutStreamer->AddComment(" On action: cleanup");
550  else
551  Asm->OutStreamer->AddComment(" On action: " +
552  Twine((S.Action - 1) / 2 + 1));
553  }
554  Asm->EmitULEB128(S.Action);
555  }
556  }
557  Asm->OutStreamer->EmitLabel(CstEndLabel);
558 
559  // Emit the Action Table.
560  int Entry = 0;
562  I = Actions.begin(), E = Actions.end(); I != E; ++I) {
563  const ActionEntry &Action = *I;
564 
565  if (VerboseAsm) {
566  // Emit comments that decode the action table.
567  Asm->OutStreamer->AddComment(">> Action Record " + Twine(++Entry) + " <<");
568  }
569 
570  // Type Filter
571  //
572  // Used by the runtime to match the type of the thrown exception to the
573  // type of the catch clauses or the types in the exception specification.
574  if (VerboseAsm) {
575  if (Action.ValueForTypeID > 0)
576  Asm->OutStreamer->AddComment(" Catch TypeInfo " +
577  Twine(Action.ValueForTypeID));
578  else if (Action.ValueForTypeID < 0)
579  Asm->OutStreamer->AddComment(" Filter TypeInfo " +
580  Twine(Action.ValueForTypeID));
581  else
582  Asm->OutStreamer->AddComment(" Cleanup");
583  }
584  Asm->EmitSLEB128(Action.ValueForTypeID);
585 
586  // Action Record
587  //
588  // Self-relative signed displacement in bytes of the next action record,
589  // or 0 if there is no next action record.
590  if (VerboseAsm) {
591  if (Action.NextAction == 0) {
592  Asm->OutStreamer->AddComment(" No further actions");
593  } else {
594  unsigned NextAction = Entry + (Action.NextAction + 1) / 2;
595  Asm->OutStreamer->AddComment(" Continue to action "+Twine(NextAction));
596  }
597  }
598  Asm->EmitSLEB128(Action.NextAction);
599  }
600 
601  if (HaveTTData) {
602  Asm->EmitAlignment(2);
603  emitTypeInfos(TTypeEncoding, TTBaseLabel);
604  }
605 
606  Asm->EmitAlignment(2);
607 }
608 
609 void EHStreamer::emitTypeInfos(unsigned TTypeEncoding, MCSymbol *TTBaseLabel) {
610  const MachineFunction *MF = Asm->MF;
611  const std::vector<const GlobalValue *> &TypeInfos = MF->getTypeInfos();
612  const std::vector<unsigned> &FilterIds = MF->getFilterIds();
613 
614  bool VerboseAsm = Asm->OutStreamer->isVerboseAsm();
615 
616  int Entry = 0;
617  // Emit the Catch TypeInfos.
618  if (VerboseAsm && !TypeInfos.empty()) {
619  Asm->OutStreamer->AddComment(">> Catch TypeInfos <<");
620  Asm->OutStreamer->AddBlankLine();
621  Entry = TypeInfos.size();
622  }
623 
624  for (const GlobalValue *GV : make_range(TypeInfos.rbegin(),
625  TypeInfos.rend())) {
626  if (VerboseAsm)
627  Asm->OutStreamer->AddComment("TypeInfo " + Twine(Entry--));
628  Asm->EmitTTypeReference(GV, TTypeEncoding);
629  }
630 
631  Asm->OutStreamer->EmitLabel(TTBaseLabel);
632 
633  // Emit the Exception Specifications.
634  if (VerboseAsm && !FilterIds.empty()) {
635  Asm->OutStreamer->AddComment(">> Filter TypeInfos <<");
636  Asm->OutStreamer->AddBlankLine();
637  Entry = 0;
638  }
639  for (std::vector<unsigned>::const_iterator
640  I = FilterIds.begin(), E = FilterIds.end(); I < E; ++I) {
641  unsigned TypeID = *I;
642  if (VerboseAsm) {
643  --Entry;
644  if (isFilterEHSelector(TypeID))
645  Asm->OutStreamer->AddComment("FilterInfo " + Twine(Entry));
646  }
647 
648  Asm->EmitULEB128(TypeID);
649  }
650 }
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
static unsigned sharedTypeIDs(const LandingPadInfo *L, const LandingPadInfo *R)
How many leading type ids two landing pads have in common.
Definition: EHStreamer.cpp:45
Structure describing an entry in the call-site table.
Definition: EHStreamer.h:62
bool isCall(QueryType Type=AnyInBundle) const
Definition: MachineInstr.h:633
typename SuperClass::const_iterator const_iterator
Definition: SmallVector.h:328
std::unique_ptr< MCStreamer > OutStreamer
This is the MCStreamer object for the file we are generating.
Definition: AsmPrinter.h:93
Compute iterated dominance frontiers using a linear time algorithm.
Definition: AllocatorList.h:24
MCSymbol - Instances of this class represent a symbol name in the MC file, and MCSymbols are created ...
Definition: MCSymbol.h:42
MCContext & OutContext
This is the context for the output file that we are streaming.
Definition: AsmPrinter.h:88
DWARF-like instruction based exceptions.
EHStreamer(AsmPrinter *A)
Definition: EHStreamer.cpp:40
This provides a very simple, boring adaptor for a begin and end iterator into a range type...
static bool callToNoUnwindFunction(const MachineInstr *MI)
Return `true&#39; if this is a call to a function marked `nounwind&#39;.
Definition: EHStreamer.cpp:169
unsigned getCallSiteBeginLabel(MCSymbol *BeginLabel) const
Get the call site number for a begin label.
F(f)
MachineFunction * MF
The current machine function.
Definition: AsmPrinter.h:96
Structure describing an entry in the actions table.
Definition: EHStreamer.h:55
void reserve(size_type N)
Definition: SmallVector.h:376
static bool isFilterEHSelector(int Selector)
Definition: EHStreamer.h:118
const LandingPadInfo * LPad
Definition: EHStreamer.h:68
const std::vector< unsigned > & getFilterIds() const
Return a reference to the typeids encoding filters used in the current function.
Twine - A lightweight data structure for efficiently representing the concatenation of temporary valu...
Definition: Twine.h:81
SmallVector< MCSymbol *, 1 > EndLabels
unsigned getNumOperands() const
Retuns the total number of operands.
Definition: MachineInstr.h:412
This class consists of common code factored out of the SmallVector class to reduce code duplication b...
Definition: APFloat.h:42
void computeActionsTable(const SmallVectorImpl< const LandingPadInfo *> &LandingPads, SmallVectorImpl< ActionEntry > &Actions, SmallVectorImpl< unsigned > &FirstActions)
Compute the actions table and gather the first action index for each landing pad site.
Definition: EHStreamer.cpp:61
TypeID
Definitions of all of the base types for the Type system.
Definition: Type.h:55
~EHStreamer() override
void emitExceptionTable()
Emit landing pads and actions.
Definition: EHStreamer.cpp:348
This structure is used to retain landing pad info for the current function.
MCSymbol * getFunctionBegin() const
Definition: AsmPrinter.h:208
void EmitLabelDifferenceAsULEB128(const MCSymbol *Hi, const MCSymbol *Lo) const
Emit something like ".uleb128 Hi-Lo".
iterator find(const_arg_type_t< KeyT > Val)
Definition: DenseMap.h:151
#define P(N)
const MCAsmInfo * MAI
Target Asm Printer information.
Definition: AsmPrinter.h:84
static GCRegistry::Add< CoreCLRGC > E("coreclr", "CoreCLR-compatible GC")
SmallVector< MCSymbol *, 1 > BeginLabels
LLVM_ATTRIBUTE_ALWAYS_INLINE iterator begin()
Definition: SmallVector.h:129
const GlobalValue * getGlobal() const
void EmitEncodingByte(unsigned Val, const char *Desc=nullptr) const
Emit a .byte 42 directive that corresponds to an encoding.
void EmitAlignment(unsigned NumBits, const GlobalObject *GV=nullptr) const
Emit an alignment directive to the specified power of two boundary.
This class is intended to be used as a driving class for all asm writers.
Definition: AsmPrinter.h:78
Type::TypeID TypeID
std::vector< int > TypeIds
size_t size() const
Definition: SmallVector.h:53
AsmPrinter * Asm
Target of directive emission.
Definition: EHStreamer.h:34
unsigned getULEB128Size(uint64_t Value)
Utility function to get the size of the ULEB128-encoded value.
Definition: LEB128.cpp:20
void sort(IteratorTy Start, IteratorTy End)
Definition: STLExtras.h:972
bool doesNotThrow() const
Determine if the function cannot unwind.
Definition: Function.h:520
iterator_range< T > make_range(T x, T y)
Convenience function for iterating over sub-ranges.
unsigned getFunctionNumber() const
Return a unique ID for the current function.
Definition: AsmPrinter.cpp:206
const std::vector< LandingPadInfo > & getLandingPads() const
Return a reference to the landing pad info for the current function.
void EmitSLEB128(int64_t Value, const char *Desc=nullptr) const
Emit the specified signed leb128 value.
bool isGlobal() const
isGlobal - Tests if this is a MO_GlobalAddress operand.
MachineOperand class - Representation of each machine instruction operand.
This is a &#39;vector&#39; (really, a variable-sized array), optimized for the case when the array is small...
Definition: SmallVector.h:847
virtual void emitTypeInfos(unsigned TTypeEncoding, MCSymbol *TTBaseLabel)
Definition: EHStreamer.cpp:609
void EmitTTypeReference(const GlobalValue *GV, unsigned Encoding) const
Emit reference to a ttype global with a specified encoding.
MCSymbol * getFunctionEnd() const
Definition: AsmPrinter.h:209
bool usesCFIForEH() const
Returns true if the exception handling method for the platform uses call frame information to unwind...
Definition: MCAsmInfo.h:579
void computeCallSiteTable(SmallVectorImpl< CallSiteEntry > &CallSites, const SmallVectorImpl< const LandingPadInfo *> &LandingPads, const SmallVectorImpl< unsigned > &FirstActions)
Compute the call-site table.
Definition: EHStreamer.cpp:225
This file contains constants used for implementing Dwarf debug support.
MCSymbol * getCurExceptionSym()
void computePadMap(const SmallVectorImpl< const LandingPadInfo *> &LandingPads, RangeMapType &PadMap)
Definition: EHStreamer.cpp:201
Representation of each machine instruction.
Definition: MachineInstr.h:64
LLVM_ATTRIBUTE_ALWAYS_INLINE iterator end()
Definition: SmallVector.h:133
MCSymbol * getOrCreateSymbol(const Twine &Name)
Lookup the symbol inside with the specified Name.
Definition: MCContext.cpp:123
#define I(x, y, z)
Definition: MD5.cpp:58
#define N
iterator end()
Definition: DenseMap.h:84
LLVM_NODISCARD std::enable_if<!is_simple_type< Y >::value, typename cast_retty< X, const Y >::ret_type >::type dyn_cast(const Y &Val)
Definition: Casting.h:323
size_type count(const_arg_type_t< KeyT > Val) const
Return 1 if the specified key is in the map, 0 otherwise.
Definition: DenseMap.h:146
unsigned getSLEB128Size(int64_t Value)
Utility function to get the size of the SLEB128-encoded value.
Definition: LEB128.cpp:30
StringRef getName() const
getName - Get the symbol name.
Definition: MCSymbol.h:203
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
void EmitULEB128(uint64_t Value, const char *Desc=nullptr) const
Emit the specified unsigned leb128 value.
ExceptionHandling getExceptionHandlingType() const
Definition: MCAsmInfo.h:570
MCSection * getLSDASection() const
IRTranslator LLVM IR MI
const std::vector< const GlobalValue * > & getTypeInfos() const
Return a reference to the C++ typeinfo for the current function.
const MachineOperand & getOperand(unsigned i) const
Definition: MachineInstr.h:414
Structure holding a try-range and the associated landing pad.
Definition: EHStreamer.h:44
MCSymbol * createTempSymbol(const Twine &Name) const
void resize(size_type N)
Definition: SmallVector.h:351