clang  3.9.0
CGCleanup.cpp
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1 //===--- CGCleanup.cpp - Bookkeeping and code emission for cleanups -------===//
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 code dealing with the IR generation for cleanups
11 // and related information.
12 //
13 // A "cleanup" is a piece of code which needs to be executed whenever
14 // control transfers out of a particular scope. This can be
15 // conditionalized to occur only on exceptional control flow, only on
16 // normal control flow, or both.
17 //
18 //===----------------------------------------------------------------------===//
19 
20 #include "CGCleanup.h"
21 #include "CodeGenFunction.h"
22 #include "llvm/Support/SaveAndRestore.h"
23 
24 using namespace clang;
25 using namespace CodeGen;
26 
28  if (rv.isScalar())
30  if (rv.isAggregate())
32  return true;
33 }
34 
37  if (rv.isScalar()) {
38  llvm::Value *V = rv.getScalarVal();
39 
40  // These automatically dominate and don't need to be saved.
42  return saved_type(V, ScalarLiteral);
43 
44  // Everything else needs an alloca.
45  Address addr =
46  CGF.CreateDefaultAlignTempAlloca(V->getType(), "saved-rvalue");
47  CGF.Builder.CreateStore(V, addr);
48  return saved_type(addr.getPointer(), ScalarAddress);
49  }
50 
51  if (rv.isComplex()) {
53  llvm::Type *ComplexTy =
54  llvm::StructType::get(V.first->getType(), V.second->getType(),
55  (void*) nullptr);
56  Address addr = CGF.CreateDefaultAlignTempAlloca(ComplexTy, "saved-complex");
57  CGF.Builder.CreateStore(V.first,
58  CGF.Builder.CreateStructGEP(addr, 0, CharUnits()));
60  CGF.CGM.getDataLayout().getTypeAllocSize(V.first->getType()));
61  CGF.Builder.CreateStore(V.second,
62  CGF.Builder.CreateStructGEP(addr, 1, offset));
63  return saved_type(addr.getPointer(), ComplexAddress);
64  }
65 
66  assert(rv.isAggregate());
67  Address V = rv.getAggregateAddress(); // TODO: volatile?
68  if (!DominatingLLVMValue::needsSaving(V.getPointer()))
69  return saved_type(V.getPointer(), AggregateLiteral,
70  V.getAlignment().getQuantity());
71 
72  Address addr =
73  CGF.CreateTempAlloca(V.getType(), CGF.getPointerAlign(), "saved-rvalue");
74  CGF.Builder.CreateStore(V.getPointer(), addr);
75  return saved_type(addr.getPointer(), AggregateAddress,
76  V.getAlignment().getQuantity());
77 }
78 
79 /// Given a saved r-value produced by SaveRValue, perform the code
80 /// necessary to restore it to usability at the current insertion
81 /// point.
83  auto getSavingAddress = [&](llvm::Value *value) {
84  auto alignment = cast<llvm::AllocaInst>(value)->getAlignment();
85  return Address(value, CharUnits::fromQuantity(alignment));
86  };
87  switch (K) {
88  case ScalarLiteral:
89  return RValue::get(Value);
90  case ScalarAddress:
91  return RValue::get(CGF.Builder.CreateLoad(getSavingAddress(Value)));
92  case AggregateLiteral:
94  case AggregateAddress: {
95  auto addr = CGF.Builder.CreateLoad(getSavingAddress(Value));
97  }
98  case ComplexAddress: {
99  Address address = getSavingAddress(Value);
100  llvm::Value *real = CGF.Builder.CreateLoad(
101  CGF.Builder.CreateStructGEP(address, 0, CharUnits()));
103  CGF.CGM.getDataLayout().getTypeAllocSize(real->getType()));
104  llvm::Value *imag = CGF.Builder.CreateLoad(
105  CGF.Builder.CreateStructGEP(address, 1, offset));
106  return RValue::getComplex(real, imag);
107  }
108  }
109 
110  llvm_unreachable("bad saved r-value kind");
111 }
112 
113 /// Push an entry of the given size onto this protected-scope stack.
114 char *EHScopeStack::allocate(size_t Size) {
115  Size = llvm::alignTo(Size, ScopeStackAlignment);
116  if (!StartOfBuffer) {
117  unsigned Capacity = 1024;
118  while (Capacity < Size) Capacity *= 2;
119  StartOfBuffer = new char[Capacity];
120  StartOfData = EndOfBuffer = StartOfBuffer + Capacity;
121  } else if (static_cast<size_t>(StartOfData - StartOfBuffer) < Size) {
122  unsigned CurrentCapacity = EndOfBuffer - StartOfBuffer;
123  unsigned UsedCapacity = CurrentCapacity - (StartOfData - StartOfBuffer);
124 
125  unsigned NewCapacity = CurrentCapacity;
126  do {
127  NewCapacity *= 2;
128  } while (NewCapacity < UsedCapacity + Size);
129 
130  char *NewStartOfBuffer = new char[NewCapacity];
131  char *NewEndOfBuffer = NewStartOfBuffer + NewCapacity;
132  char *NewStartOfData = NewEndOfBuffer - UsedCapacity;
133  memcpy(NewStartOfData, StartOfData, UsedCapacity);
134  delete [] StartOfBuffer;
135  StartOfBuffer = NewStartOfBuffer;
136  EndOfBuffer = NewEndOfBuffer;
137  StartOfData = NewStartOfData;
138  }
139 
140  assert(StartOfBuffer + Size <= StartOfData);
141  StartOfData -= Size;
142  return StartOfData;
143 }
144 
145 void EHScopeStack::deallocate(size_t Size) {
146  StartOfData += llvm::alignTo(Size, ScopeStackAlignment);
147 }
148 
150  EHScopeStack::stable_iterator Old) const {
151  for (EHScopeStack::iterator it = begin(); stabilize(it) != Old; it++) {
152  EHCleanupScope *cleanup = dyn_cast<EHCleanupScope>(&*it);
153  if (!cleanup || !cleanup->isLifetimeMarker())
154  return false;
155  }
156 
157  return true;
158 }
159 
161  for (stable_iterator si = getInnermostEHScope(); si != stable_end(); ) {
162  // Skip lifetime markers.
163  if (auto *cleanup = dyn_cast<EHCleanupScope>(&*find(si)))
164  if (cleanup->isLifetimeMarker()) {
165  si = cleanup->getEnclosingEHScope();
166  continue;
167  }
168  return true;
169  }
170 
171  return false;
172 }
173 
177  si != se; ) {
178  EHCleanupScope &cleanup = cast<EHCleanupScope>(*find(si));
179  if (cleanup.isActive()) return si;
180  si = cleanup.getEnclosingNormalCleanup();
181  }
182  return stable_end();
183 }
184 
185 
186 void *EHScopeStack::pushCleanup(CleanupKind Kind, size_t Size) {
187  char *Buffer = allocate(EHCleanupScope::getSizeForCleanupSize(Size));
188  bool IsNormalCleanup = Kind & NormalCleanup;
189  bool IsEHCleanup = Kind & EHCleanup;
190  bool IsActive = !(Kind & InactiveCleanup);
191  bool IsLifetimeMarker = Kind & LifetimeMarker;
193  new (Buffer) EHCleanupScope(IsNormalCleanup,
194  IsEHCleanup,
195  IsActive,
196  Size,
197  BranchFixups.size(),
198  InnermostNormalCleanup,
199  InnermostEHScope);
200  if (IsNormalCleanup)
201  InnermostNormalCleanup = stable_begin();
202  if (IsEHCleanup)
203  InnermostEHScope = stable_begin();
204  if (IsLifetimeMarker)
205  Scope->setLifetimeMarker();
206 
207  return Scope->getCleanupBuffer();
208 }
209 
211  assert(!empty() && "popping exception stack when not empty");
212 
213  assert(isa<EHCleanupScope>(*begin()));
214  EHCleanupScope &Cleanup = cast<EHCleanupScope>(*begin());
215  InnermostNormalCleanup = Cleanup.getEnclosingNormalCleanup();
216  InnermostEHScope = Cleanup.getEnclosingEHScope();
217  deallocate(Cleanup.getAllocatedSize());
218 
219  // Destroy the cleanup.
220  Cleanup.Destroy();
221 
222  // Check whether we can shrink the branch-fixups stack.
223  if (!BranchFixups.empty()) {
224  // If we no longer have any normal cleanups, all the fixups are
225  // complete.
226  if (!hasNormalCleanups())
227  BranchFixups.clear();
228 
229  // Otherwise we can still trim out unnecessary nulls.
230  else
231  popNullFixups();
232  }
233 }
234 
236  assert(getInnermostEHScope() == stable_end());
237  char *buffer = allocate(EHFilterScope::getSizeForNumFilters(numFilters));
238  EHFilterScope *filter = new (buffer) EHFilterScope(numFilters);
239  InnermostEHScope = stable_begin();
240  return filter;
241 }
242 
244  assert(!empty() && "popping exception stack when not empty");
245 
246  EHFilterScope &filter = cast<EHFilterScope>(*begin());
248 
249  InnermostEHScope = filter.getEnclosingEHScope();
250 }
251 
252 EHCatchScope *EHScopeStack::pushCatch(unsigned numHandlers) {
253  char *buffer = allocate(EHCatchScope::getSizeForNumHandlers(numHandlers));
254  EHCatchScope *scope =
255  new (buffer) EHCatchScope(numHandlers, InnermostEHScope);
256  InnermostEHScope = stable_begin();
257  return scope;
258 }
259 
261  char *Buffer = allocate(EHTerminateScope::getSize());
262  new (Buffer) EHTerminateScope(InnermostEHScope);
263  InnermostEHScope = stable_begin();
264 }
265 
266 /// Remove any 'null' fixups on the stack. However, we can't pop more
267 /// fixups than the fixup depth on the innermost normal cleanup, or
268 /// else fixups that we try to add to that cleanup will end up in the
269 /// wrong place. We *could* try to shrink fixup depths, but that's
270 /// actually a lot of work for little benefit.
272  // We expect this to only be called when there's still an innermost
273  // normal cleanup; otherwise there really shouldn't be any fixups.
274  assert(hasNormalCleanups());
275 
276  EHScopeStack::iterator it = find(InnermostNormalCleanup);
277  unsigned MinSize = cast<EHCleanupScope>(*it).getFixupDepth();
278  assert(BranchFixups.size() >= MinSize && "fixup stack out of order");
279 
280  while (BranchFixups.size() > MinSize &&
281  BranchFixups.back().Destination == nullptr)
282  BranchFixups.pop_back();
283 }
284 
286  // Create a variable to decide whether the cleanup needs to be run.
287  Address active = CreateTempAlloca(Builder.getInt1Ty(), CharUnits::One(),
288  "cleanup.cond");
289 
290  // Initialize it to false at a site that's guaranteed to be run
291  // before each evaluation.
292  setBeforeOutermostConditional(Builder.getFalse(), active);
293 
294  // Initialize it to true at the current location.
295  Builder.CreateStore(Builder.getTrue(), active);
296 
297  // Set that as the active flag in the cleanup.
298  EHCleanupScope &cleanup = cast<EHCleanupScope>(*EHStack.begin());
299  assert(!cleanup.hasActiveFlag() && "cleanup already has active flag?");
300  cleanup.setActiveFlag(active);
301 
302  if (cleanup.isNormalCleanup()) cleanup.setTestFlagInNormalCleanup();
303  if (cleanup.isEHCleanup()) cleanup.setTestFlagInEHCleanup();
304 }
305 
306 void EHScopeStack::Cleanup::anchor() {}
307 
308 static void createStoreInstBefore(llvm::Value *value, Address addr,
309  llvm::Instruction *beforeInst) {
310  auto store = new llvm::StoreInst(value, addr.getPointer(), beforeInst);
311  store->setAlignment(addr.getAlignment().getQuantity());
312 }
313 
314 static llvm::LoadInst *createLoadInstBefore(Address addr, const Twine &name,
315  llvm::Instruction *beforeInst) {
316  auto load = new llvm::LoadInst(addr.getPointer(), name, beforeInst);
317  load->setAlignment(addr.getAlignment().getQuantity());
318  return load;
319 }
320 
321 /// All the branch fixups on the EH stack have propagated out past the
322 /// outermost normal cleanup; resolve them all by adding cases to the
323 /// given switch instruction.
325  llvm::SwitchInst *Switch,
326  llvm::BasicBlock *CleanupEntry) {
327  llvm::SmallPtrSet<llvm::BasicBlock*, 4> CasesAdded;
328 
329  for (unsigned I = 0, E = CGF.EHStack.getNumBranchFixups(); I != E; ++I) {
330  // Skip this fixup if its destination isn't set.
331  BranchFixup &Fixup = CGF.EHStack.getBranchFixup(I);
332  if (Fixup.Destination == nullptr) continue;
333 
334  // If there isn't an OptimisticBranchBlock, then InitialBranch is
335  // still pointing directly to its destination; forward it to the
336  // appropriate cleanup entry. This is required in the specific
337  // case of
338  // { std::string s; goto lbl; }
339  // lbl:
340  // i.e. where there's an unresolved fixup inside a single cleanup
341  // entry which we're currently popping.
342  if (Fixup.OptimisticBranchBlock == nullptr) {
343  createStoreInstBefore(CGF.Builder.getInt32(Fixup.DestinationIndex),
345  Fixup.InitialBranch);
346  Fixup.InitialBranch->setSuccessor(0, CleanupEntry);
347  }
348 
349  // Don't add this case to the switch statement twice.
350  if (!CasesAdded.insert(Fixup.Destination).second)
351  continue;
352 
353  Switch->addCase(CGF.Builder.getInt32(Fixup.DestinationIndex),
354  Fixup.Destination);
355  }
356 
357  CGF.EHStack.clearFixups();
358 }
359 
360 /// Transitions the terminator of the given exit-block of a cleanup to
361 /// be a cleanup switch.
362 static llvm::SwitchInst *TransitionToCleanupSwitch(CodeGenFunction &CGF,
363  llvm::BasicBlock *Block) {
364  // If it's a branch, turn it into a switch whose default
365  // destination is its original target.
366  llvm::TerminatorInst *Term = Block->getTerminator();
367  assert(Term && "can't transition block without terminator");
368 
369  if (llvm::BranchInst *Br = dyn_cast<llvm::BranchInst>(Term)) {
370  assert(Br->isUnconditional());
372  "cleanup.dest", Term);
373  llvm::SwitchInst *Switch =
374  llvm::SwitchInst::Create(Load, Br->getSuccessor(0), 4, Block);
375  Br->eraseFromParent();
376  return Switch;
377  } else {
378  return cast<llvm::SwitchInst>(Term);
379  }
380 }
381 
382 void CodeGenFunction::ResolveBranchFixups(llvm::BasicBlock *Block) {
383  assert(Block && "resolving a null target block");
384  if (!EHStack.getNumBranchFixups()) return;
385 
386  assert(EHStack.hasNormalCleanups() &&
387  "branch fixups exist with no normal cleanups on stack");
388 
389  llvm::SmallPtrSet<llvm::BasicBlock*, 4> ModifiedOptimisticBlocks;
390  bool ResolvedAny = false;
391 
392  for (unsigned I = 0, E = EHStack.getNumBranchFixups(); I != E; ++I) {
393  // Skip this fixup if its destination doesn't match.
394  BranchFixup &Fixup = EHStack.getBranchFixup(I);
395  if (Fixup.Destination != Block) continue;
396 
397  Fixup.Destination = nullptr;
398  ResolvedAny = true;
399 
400  // If it doesn't have an optimistic branch block, LatestBranch is
401  // already pointing to the right place.
402  llvm::BasicBlock *BranchBB = Fixup.OptimisticBranchBlock;
403  if (!BranchBB)
404  continue;
405 
406  // Don't process the same optimistic branch block twice.
407  if (!ModifiedOptimisticBlocks.insert(BranchBB).second)
408  continue;
409 
410  llvm::SwitchInst *Switch = TransitionToCleanupSwitch(*this, BranchBB);
411 
412  // Add a case to the switch.
413  Switch->addCase(Builder.getInt32(Fixup.DestinationIndex), Block);
414  }
415 
416  if (ResolvedAny)
417  EHStack.popNullFixups();
418 }
419 
420 /// Pops cleanup blocks until the given savepoint is reached.
422  assert(Old.isValid());
423 
424  while (EHStack.stable_begin() != Old) {
425  EHCleanupScope &Scope = cast<EHCleanupScope>(*EHStack.begin());
426 
427  // As long as Old strictly encloses the scope's enclosing normal
428  // cleanup, we're going to emit another normal cleanup which
429  // fallthrough can propagate through.
430  bool FallThroughIsBranchThrough =
431  Old.strictlyEncloses(Scope.getEnclosingNormalCleanup());
432 
433  PopCleanupBlock(FallThroughIsBranchThrough);
434  }
435 }
436 
437 /// Pops cleanup blocks until the given savepoint is reached, then add the
438 /// cleanups from the given savepoint in the lifetime-extended cleanups stack.
439 void
441  size_t OldLifetimeExtendedSize) {
442  PopCleanupBlocks(Old);
443 
444  // Move our deferred cleanups onto the EH stack.
445  for (size_t I = OldLifetimeExtendedSize,
446  E = LifetimeExtendedCleanupStack.size(); I != E; /**/) {
447  // Alignment should be guaranteed by the vptrs in the individual cleanups.
448  assert((I % llvm::alignOf<LifetimeExtendedCleanupHeader>() == 0) &&
449  "misaligned cleanup stack entry");
450 
452  reinterpret_cast<LifetimeExtendedCleanupHeader&>(
453  LifetimeExtendedCleanupStack[I]);
454  I += sizeof(Header);
455 
456  EHStack.pushCopyOfCleanup(Header.getKind(),
457  &LifetimeExtendedCleanupStack[I],
458  Header.getSize());
459  I += Header.getSize();
460  }
461  LifetimeExtendedCleanupStack.resize(OldLifetimeExtendedSize);
462 }
463 
464 static llvm::BasicBlock *CreateNormalEntry(CodeGenFunction &CGF,
465  EHCleanupScope &Scope) {
466  assert(Scope.isNormalCleanup());
467  llvm::BasicBlock *Entry = Scope.getNormalBlock();
468  if (!Entry) {
469  Entry = CGF.createBasicBlock("cleanup");
470  Scope.setNormalBlock(Entry);
471  }
472  return Entry;
473 }
474 
475 /// Attempts to reduce a cleanup's entry block to a fallthrough. This
476 /// is basically llvm::MergeBlockIntoPredecessor, except
477 /// simplified/optimized for the tighter constraints on cleanup blocks.
478 ///
479 /// Returns the new block, whatever it is.
480 static llvm::BasicBlock *SimplifyCleanupEntry(CodeGenFunction &CGF,
481  llvm::BasicBlock *Entry) {
482  llvm::BasicBlock *Pred = Entry->getSinglePredecessor();
483  if (!Pred) return Entry;
484 
485  llvm::BranchInst *Br = dyn_cast<llvm::BranchInst>(Pred->getTerminator());
486  if (!Br || Br->isConditional()) return Entry;
487  assert(Br->getSuccessor(0) == Entry);
488 
489  // If we were previously inserting at the end of the cleanup entry
490  // block, we'll need to continue inserting at the end of the
491  // predecessor.
492  bool WasInsertBlock = CGF.Builder.GetInsertBlock() == Entry;
493  assert(!WasInsertBlock || CGF.Builder.GetInsertPoint() == Entry->end());
494 
495  // Kill the branch.
496  Br->eraseFromParent();
497 
498  // Replace all uses of the entry with the predecessor, in case there
499  // are phis in the cleanup.
500  Entry->replaceAllUsesWith(Pred);
501 
502  // Merge the blocks.
503  Pred->getInstList().splice(Pred->end(), Entry->getInstList());
504 
505  // Kill the entry block.
506  Entry->eraseFromParent();
507 
508  if (WasInsertBlock)
509  CGF.Builder.SetInsertPoint(Pred);
510 
511  return Pred;
512 }
513 
514 static void EmitCleanup(CodeGenFunction &CGF,
518  // If there's an active flag, load it and skip the cleanup if it's
519  // false.
520  llvm::BasicBlock *ContBB = nullptr;
521  if (ActiveFlag.isValid()) {
522  ContBB = CGF.createBasicBlock("cleanup.done");
523  llvm::BasicBlock *CleanupBB = CGF.createBasicBlock("cleanup.action");
524  llvm::Value *IsActive
525  = CGF.Builder.CreateLoad(ActiveFlag, "cleanup.is_active");
526  CGF.Builder.CreateCondBr(IsActive, CleanupBB, ContBB);
527  CGF.EmitBlock(CleanupBB);
528  }
529 
530  // Ask the cleanup to emit itself.
531  Fn->Emit(CGF, flags);
532  assert(CGF.HaveInsertPoint() && "cleanup ended with no insertion point?");
533 
534  // Emit the continuation block if there was an active flag.
535  if (ActiveFlag.isValid())
536  CGF.EmitBlock(ContBB);
537 }
538 
539 static void ForwardPrebranchedFallthrough(llvm::BasicBlock *Exit,
540  llvm::BasicBlock *From,
541  llvm::BasicBlock *To) {
542  // Exit is the exit block of a cleanup, so it always terminates in
543  // an unconditional branch or a switch.
544  llvm::TerminatorInst *Term = Exit->getTerminator();
545 
546  if (llvm::BranchInst *Br = dyn_cast<llvm::BranchInst>(Term)) {
547  assert(Br->isUnconditional() && Br->getSuccessor(0) == From);
548  Br->setSuccessor(0, To);
549  } else {
550  llvm::SwitchInst *Switch = cast<llvm::SwitchInst>(Term);
551  for (unsigned I = 0, E = Switch->getNumSuccessors(); I != E; ++I)
552  if (Switch->getSuccessor(I) == From)
553  Switch->setSuccessor(I, To);
554  }
555 }
556 
557 /// We don't need a normal entry block for the given cleanup.
558 /// Optimistic fixup branches can cause these blocks to come into
559 /// existence anyway; if so, destroy it.
560 ///
561 /// The validity of this transformation is very much specific to the
562 /// exact ways in which we form branches to cleanup entries.
564  EHCleanupScope &scope) {
565  llvm::BasicBlock *entry = scope.getNormalBlock();
566  if (!entry) return;
567 
568  // Replace all the uses with unreachable.
569  llvm::BasicBlock *unreachableBB = CGF.getUnreachableBlock();
570  for (llvm::BasicBlock::use_iterator
571  i = entry->use_begin(), e = entry->use_end(); i != e; ) {
572  llvm::Use &use = *i;
573  ++i;
574 
575  use.set(unreachableBB);
576 
577  // The only uses should be fixup switches.
578  llvm::SwitchInst *si = cast<llvm::SwitchInst>(use.getUser());
579  if (si->getNumCases() == 1 && si->getDefaultDest() == unreachableBB) {
580  // Replace the switch with a branch.
581  llvm::BranchInst::Create(si->case_begin().getCaseSuccessor(), si);
582 
583  // The switch operand is a load from the cleanup-dest alloca.
584  llvm::LoadInst *condition = cast<llvm::LoadInst>(si->getCondition());
585 
586  // Destroy the switch.
587  si->eraseFromParent();
588 
589  // Destroy the load.
590  assert(condition->getOperand(0) == CGF.NormalCleanupDest);
591  assert(condition->use_empty());
592  condition->eraseFromParent();
593  }
594  }
595 
596  assert(entry->use_empty());
597  delete entry;
598 }
599 
600 /// Pops a cleanup block. If the block includes a normal cleanup, the
601 /// current insertion point is threaded through the cleanup, as are
602 /// any branch fixups on the cleanup.
603 void CodeGenFunction::PopCleanupBlock(bool FallthroughIsBranchThrough) {
604  assert(!EHStack.empty() && "cleanup stack is empty!");
605  assert(isa<EHCleanupScope>(*EHStack.begin()) && "top not a cleanup!");
606  EHCleanupScope &Scope = cast<EHCleanupScope>(*EHStack.begin());
607  assert(Scope.getFixupDepth() <= EHStack.getNumBranchFixups());
608 
609  // Remember activation information.
610  bool IsActive = Scope.isActive();
611  Address NormalActiveFlag =
612  Scope.shouldTestFlagInNormalCleanup() ? Scope.getActiveFlag()
613  : Address::invalid();
614  Address EHActiveFlag =
615  Scope.shouldTestFlagInEHCleanup() ? Scope.getActiveFlag()
616  : Address::invalid();
617 
618  // Check whether we need an EH cleanup. This is only true if we've
619  // generated a lazy EH cleanup block.
620  llvm::BasicBlock *EHEntry = Scope.getCachedEHDispatchBlock();
621  assert(Scope.hasEHBranches() == (EHEntry != nullptr));
622  bool RequiresEHCleanup = (EHEntry != nullptr);
623  EHScopeStack::stable_iterator EHParent = Scope.getEnclosingEHScope();
624 
625  // Check the three conditions which might require a normal cleanup:
626 
627  // - whether there are branch fix-ups through this cleanup
628  unsigned FixupDepth = Scope.getFixupDepth();
629  bool HasFixups = EHStack.getNumBranchFixups() != FixupDepth;
630 
631  // - whether there are branch-throughs or branch-afters
632  bool HasExistingBranches = Scope.hasBranches();
633 
634  // - whether there's a fallthrough
635  llvm::BasicBlock *FallthroughSource = Builder.GetInsertBlock();
636  bool HasFallthrough = (FallthroughSource != nullptr && IsActive);
637 
638  // Branch-through fall-throughs leave the insertion point set to the
639  // end of the last cleanup, which points to the current scope. The
640  // rest of IR gen doesn't need to worry about this; it only happens
641  // during the execution of PopCleanupBlocks().
642  bool HasPrebranchedFallthrough =
643  (FallthroughSource && FallthroughSource->getTerminator());
644 
645  // If this is a normal cleanup, then having a prebranched
646  // fallthrough implies that the fallthrough source unconditionally
647  // jumps here.
648  assert(!Scope.isNormalCleanup() || !HasPrebranchedFallthrough ||
649  (Scope.getNormalBlock() &&
650  FallthroughSource->getTerminator()->getSuccessor(0)
651  == Scope.getNormalBlock()));
652 
653  bool RequiresNormalCleanup = false;
654  if (Scope.isNormalCleanup() &&
655  (HasFixups || HasExistingBranches || HasFallthrough)) {
656  RequiresNormalCleanup = true;
657  }
658 
659  // If we have a prebranched fallthrough into an inactive normal
660  // cleanup, rewrite it so that it leads to the appropriate place.
661  if (Scope.isNormalCleanup() && HasPrebranchedFallthrough && !IsActive) {
662  llvm::BasicBlock *prebranchDest;
663 
664  // If the prebranch is semantically branching through the next
665  // cleanup, just forward it to the next block, leaving the
666  // insertion point in the prebranched block.
667  if (FallthroughIsBranchThrough) {
668  EHScope &enclosing = *EHStack.find(Scope.getEnclosingNormalCleanup());
669  prebranchDest = CreateNormalEntry(*this, cast<EHCleanupScope>(enclosing));
670 
671  // Otherwise, we need to make a new block. If the normal cleanup
672  // isn't being used at all, we could actually reuse the normal
673  // entry block, but this is simpler, and it avoids conflicts with
674  // dead optimistic fixup branches.
675  } else {
676  prebranchDest = createBasicBlock("forwarded-prebranch");
677  EmitBlock(prebranchDest);
678  }
679 
680  llvm::BasicBlock *normalEntry = Scope.getNormalBlock();
681  assert(normalEntry && !normalEntry->use_empty());
682 
683  ForwardPrebranchedFallthrough(FallthroughSource,
684  normalEntry, prebranchDest);
685  }
686 
687  // If we don't need the cleanup at all, we're done.
688  if (!RequiresNormalCleanup && !RequiresEHCleanup) {
689  destroyOptimisticNormalEntry(*this, Scope);
690  EHStack.popCleanup(); // safe because there are no fixups
691  assert(EHStack.getNumBranchFixups() == 0 ||
692  EHStack.hasNormalCleanups());
693  return;
694  }
695 
696  // Copy the cleanup emission data out. This uses either a stack
697  // array or malloc'd memory, depending on the size, which is
698  // behavior that SmallVector would provide, if we could use it
699  // here. Unfortunately, if you ask for a SmallVector<char>, the
700  // alignment isn't sufficient.
701  auto *CleanupSource = reinterpret_cast<char *>(Scope.getCleanupBuffer());
702  llvm::AlignedCharArray<EHScopeStack::ScopeStackAlignment, 8 * sizeof(void *)> CleanupBufferStack;
703  std::unique_ptr<char[]> CleanupBufferHeap;
704  size_t CleanupSize = Scope.getCleanupSize();
706 
707  if (CleanupSize <= sizeof(CleanupBufferStack)) {
708  memcpy(CleanupBufferStack.buffer, CleanupSource, CleanupSize);
709  Fn = reinterpret_cast<EHScopeStack::Cleanup *>(CleanupBufferStack.buffer);
710  } else {
711  CleanupBufferHeap.reset(new char[CleanupSize]);
712  memcpy(CleanupBufferHeap.get(), CleanupSource, CleanupSize);
713  Fn = reinterpret_cast<EHScopeStack::Cleanup *>(CleanupBufferHeap.get());
714  }
715 
716  EHScopeStack::Cleanup::Flags cleanupFlags;
717  if (Scope.isNormalCleanup())
718  cleanupFlags.setIsNormalCleanupKind();
719  if (Scope.isEHCleanup())
720  cleanupFlags.setIsEHCleanupKind();
721 
722  if (!RequiresNormalCleanup) {
723  destroyOptimisticNormalEntry(*this, Scope);
724  EHStack.popCleanup();
725  } else {
726  // If we have a fallthrough and no other need for the cleanup,
727  // emit it directly.
728  if (HasFallthrough && !HasPrebranchedFallthrough &&
729  !HasFixups && !HasExistingBranches) {
730 
731  destroyOptimisticNormalEntry(*this, Scope);
732  EHStack.popCleanup();
733 
734  EmitCleanup(*this, Fn, cleanupFlags, NormalActiveFlag);
735 
736  // Otherwise, the best approach is to thread everything through
737  // the cleanup block and then try to clean up after ourselves.
738  } else {
739  // Force the entry block to exist.
740  llvm::BasicBlock *NormalEntry = CreateNormalEntry(*this, Scope);
741 
742  // I. Set up the fallthrough edge in.
743 
744  CGBuilderTy::InsertPoint savedInactiveFallthroughIP;
745 
746  // If there's a fallthrough, we need to store the cleanup
747  // destination index. For fall-throughs this is always zero.
748  if (HasFallthrough) {
749  if (!HasPrebranchedFallthrough)
750  Builder.CreateStore(Builder.getInt32(0), getNormalCleanupDestSlot());
751 
752  // Otherwise, save and clear the IP if we don't have fallthrough
753  // because the cleanup is inactive.
754  } else if (FallthroughSource) {
755  assert(!IsActive && "source without fallthrough for active cleanup");
756  savedInactiveFallthroughIP = Builder.saveAndClearIP();
757  }
758 
759  // II. Emit the entry block. This implicitly branches to it if
760  // we have fallthrough. All the fixups and existing branches
761  // should already be branched to it.
762  EmitBlock(NormalEntry);
763 
764  // III. Figure out where we're going and build the cleanup
765  // epilogue.
766 
767  bool HasEnclosingCleanups =
768  (Scope.getEnclosingNormalCleanup() != EHStack.stable_end());
769 
770  // Compute the branch-through dest if we need it:
771  // - if there are branch-throughs threaded through the scope
772  // - if fall-through is a branch-through
773  // - if there are fixups that will be optimistically forwarded
774  // to the enclosing cleanup
775  llvm::BasicBlock *BranchThroughDest = nullptr;
776  if (Scope.hasBranchThroughs() ||
777  (FallthroughSource && FallthroughIsBranchThrough) ||
778  (HasFixups && HasEnclosingCleanups)) {
779  assert(HasEnclosingCleanups);
780  EHScope &S = *EHStack.find(Scope.getEnclosingNormalCleanup());
781  BranchThroughDest = CreateNormalEntry(*this, cast<EHCleanupScope>(S));
782  }
783 
784  llvm::BasicBlock *FallthroughDest = nullptr;
786 
787  // If there's exactly one branch-after and no other threads,
788  // we can route it without a switch.
789  if (!Scope.hasBranchThroughs() && !HasFixups && !HasFallthrough &&
790  Scope.getNumBranchAfters() == 1) {
791  assert(!BranchThroughDest || !IsActive);
792 
793  // Clean up the possibly dead store to the cleanup dest slot.
794  llvm::Instruction *NormalCleanupDestSlot =
795  cast<llvm::Instruction>(getNormalCleanupDestSlot().getPointer());
796  if (NormalCleanupDestSlot->hasOneUse()) {
797  NormalCleanupDestSlot->user_back()->eraseFromParent();
798  NormalCleanupDestSlot->eraseFromParent();
799  NormalCleanupDest = nullptr;
800  }
801 
802  llvm::BasicBlock *BranchAfter = Scope.getBranchAfterBlock(0);
803  InstsToAppend.push_back(llvm::BranchInst::Create(BranchAfter));
804 
805  // Build a switch-out if we need it:
806  // - if there are branch-afters threaded through the scope
807  // - if fall-through is a branch-after
808  // - if there are fixups that have nowhere left to go and
809  // so must be immediately resolved
810  } else if (Scope.getNumBranchAfters() ||
811  (HasFallthrough && !FallthroughIsBranchThrough) ||
812  (HasFixups && !HasEnclosingCleanups)) {
813 
814  llvm::BasicBlock *Default =
815  (BranchThroughDest ? BranchThroughDest : getUnreachableBlock());
816 
817  // TODO: base this on the number of branch-afters and fixups
818  const unsigned SwitchCapacity = 10;
819 
820  llvm::LoadInst *Load =
821  createLoadInstBefore(getNormalCleanupDestSlot(), "cleanup.dest",
822  nullptr);
823  llvm::SwitchInst *Switch =
824  llvm::SwitchInst::Create(Load, Default, SwitchCapacity);
825 
826  InstsToAppend.push_back(Load);
827  InstsToAppend.push_back(Switch);
828 
829  // Branch-after fallthrough.
830  if (FallthroughSource && !FallthroughIsBranchThrough) {
831  FallthroughDest = createBasicBlock("cleanup.cont");
832  if (HasFallthrough)
833  Switch->addCase(Builder.getInt32(0), FallthroughDest);
834  }
835 
836  for (unsigned I = 0, E = Scope.getNumBranchAfters(); I != E; ++I) {
837  Switch->addCase(Scope.getBranchAfterIndex(I),
838  Scope.getBranchAfterBlock(I));
839  }
840 
841  // If there aren't any enclosing cleanups, we can resolve all
842  // the fixups now.
843  if (HasFixups && !HasEnclosingCleanups)
844  ResolveAllBranchFixups(*this, Switch, NormalEntry);
845  } else {
846  // We should always have a branch-through destination in this case.
847  assert(BranchThroughDest);
848  InstsToAppend.push_back(llvm::BranchInst::Create(BranchThroughDest));
849  }
850 
851  // IV. Pop the cleanup and emit it.
852  EHStack.popCleanup();
853  assert(EHStack.hasNormalCleanups() == HasEnclosingCleanups);
854 
855  EmitCleanup(*this, Fn, cleanupFlags, NormalActiveFlag);
856 
857  // Append the prepared cleanup prologue from above.
858  llvm::BasicBlock *NormalExit = Builder.GetInsertBlock();
859  for (unsigned I = 0, E = InstsToAppend.size(); I != E; ++I)
860  NormalExit->getInstList().push_back(InstsToAppend[I]);
861 
862  // Optimistically hope that any fixups will continue falling through.
863  for (unsigned I = FixupDepth, E = EHStack.getNumBranchFixups();
864  I < E; ++I) {
865  BranchFixup &Fixup = EHStack.getBranchFixup(I);
866  if (!Fixup.Destination) continue;
867  if (!Fixup.OptimisticBranchBlock) {
869  getNormalCleanupDestSlot(),
870  Fixup.InitialBranch);
871  Fixup.InitialBranch->setSuccessor(0, NormalEntry);
872  }
873  Fixup.OptimisticBranchBlock = NormalExit;
874  }
875 
876  // V. Set up the fallthrough edge out.
877 
878  // Case 1: a fallthrough source exists but doesn't branch to the
879  // cleanup because the cleanup is inactive.
880  if (!HasFallthrough && FallthroughSource) {
881  // Prebranched fallthrough was forwarded earlier.
882  // Non-prebranched fallthrough doesn't need to be forwarded.
883  // Either way, all we need to do is restore the IP we cleared before.
884  assert(!IsActive);
885  Builder.restoreIP(savedInactiveFallthroughIP);
886 
887  // Case 2: a fallthrough source exists and should branch to the
888  // cleanup, but we're not supposed to branch through to the next
889  // cleanup.
890  } else if (HasFallthrough && FallthroughDest) {
891  assert(!FallthroughIsBranchThrough);
892  EmitBlock(FallthroughDest);
893 
894  // Case 3: a fallthrough source exists and should branch to the
895  // cleanup and then through to the next.
896  } else if (HasFallthrough) {
897  // Everything is already set up for this.
898 
899  // Case 4: no fallthrough source exists.
900  } else {
901  Builder.ClearInsertionPoint();
902  }
903 
904  // VI. Assorted cleaning.
905 
906  // Check whether we can merge NormalEntry into a single predecessor.
907  // This might invalidate (non-IR) pointers to NormalEntry.
908  llvm::BasicBlock *NewNormalEntry =
909  SimplifyCleanupEntry(*this, NormalEntry);
910 
911  // If it did invalidate those pointers, and NormalEntry was the same
912  // as NormalExit, go back and patch up the fixups.
913  if (NewNormalEntry != NormalEntry && NormalEntry == NormalExit)
914  for (unsigned I = FixupDepth, E = EHStack.getNumBranchFixups();
915  I < E; ++I)
916  EHStack.getBranchFixup(I).OptimisticBranchBlock = NewNormalEntry;
917  }
918  }
919 
920  assert(EHStack.hasNormalCleanups() || EHStack.getNumBranchFixups() == 0);
921 
922  // Emit the EH cleanup if required.
923  if (RequiresEHCleanup) {
924  CGBuilderTy::InsertPoint SavedIP = Builder.saveAndClearIP();
925 
926  EmitBlock(EHEntry);
927 
928  llvm::BasicBlock *NextAction = getEHDispatchBlock(EHParent);
929 
930  // Push a terminate scope or cleanupendpad scope around the potentially
931  // throwing cleanups. For funclet EH personalities, the cleanupendpad models
932  // program termination when cleanups throw.
933  bool PushedTerminate = false;
934  SaveAndRestore<llvm::Instruction *> RestoreCurrentFuncletPad(
935  CurrentFuncletPad);
936  llvm::CleanupPadInst *CPI = nullptr;
937  if (!EHPersonality::get(*this).usesFuncletPads()) {
938  EHStack.pushTerminate();
939  PushedTerminate = true;
940  } else {
941  llvm::Value *ParentPad = CurrentFuncletPad;
942  if (!ParentPad)
943  ParentPad = llvm::ConstantTokenNone::get(CGM.getLLVMContext());
944  CurrentFuncletPad = CPI = Builder.CreateCleanupPad(ParentPad);
945  }
946 
947  // We only actually emit the cleanup code if the cleanup is either
948  // active or was used before it was deactivated.
949  if (EHActiveFlag.isValid() || IsActive) {
950  cleanupFlags.setIsForEHCleanup();
951  EmitCleanup(*this, Fn, cleanupFlags, EHActiveFlag);
952  }
953 
954  if (CPI)
955  Builder.CreateCleanupRet(CPI, NextAction);
956  else
957  Builder.CreateBr(NextAction);
958 
959  // Leave the terminate scope.
960  if (PushedTerminate)
961  EHStack.popTerminate();
962 
963  Builder.restoreIP(SavedIP);
964 
965  SimplifyCleanupEntry(*this, EHEntry);
966  }
967 }
968 
969 /// isObviouslyBranchWithoutCleanups - Return true if a branch to the
970 /// specified destination obviously has no cleanups to run. 'false' is always
971 /// a conservatively correct answer for this method.
973  assert(Dest.getScopeDepth().encloses(EHStack.stable_begin())
974  && "stale jump destination");
975 
976  // Calculate the innermost active normal cleanup.
977  EHScopeStack::stable_iterator TopCleanup =
978  EHStack.getInnermostActiveNormalCleanup();
979 
980  // If we're not in an active normal cleanup scope, or if the
981  // destination scope is within the innermost active normal cleanup
982  // scope, we don't need to worry about fixups.
983  if (TopCleanup == EHStack.stable_end() ||
984  TopCleanup.encloses(Dest.getScopeDepth())) // works for invalid
985  return true;
986 
987  // Otherwise, we might need some cleanups.
988  return false;
989 }
990 
991 
992 /// Terminate the current block by emitting a branch which might leave
993 /// the current cleanup-protected scope. The target scope may not yet
994 /// be known, in which case this will require a fixup.
995 ///
996 /// As a side-effect, this method clears the insertion point.
998  assert(Dest.getScopeDepth().encloses(EHStack.stable_begin())
999  && "stale jump destination");
1000 
1001  if (!HaveInsertPoint())
1002  return;
1003 
1004  // Create the branch.
1005  llvm::BranchInst *BI = Builder.CreateBr(Dest.getBlock());
1006 
1007  // Calculate the innermost active normal cleanup.
1009  TopCleanup = EHStack.getInnermostActiveNormalCleanup();
1010 
1011  // If we're not in an active normal cleanup scope, or if the
1012  // destination scope is within the innermost active normal cleanup
1013  // scope, we don't need to worry about fixups.
1014  if (TopCleanup == EHStack.stable_end() ||
1015  TopCleanup.encloses(Dest.getScopeDepth())) { // works for invalid
1016  Builder.ClearInsertionPoint();
1017  return;
1018  }
1019 
1020  // If we can't resolve the destination cleanup scope, just add this
1021  // to the current cleanup scope as a branch fixup.
1022  if (!Dest.getScopeDepth().isValid()) {
1023  BranchFixup &Fixup = EHStack.addBranchFixup();
1024  Fixup.Destination = Dest.getBlock();
1025  Fixup.DestinationIndex = Dest.getDestIndex();
1026  Fixup.InitialBranch = BI;
1027  Fixup.OptimisticBranchBlock = nullptr;
1028 
1029  Builder.ClearInsertionPoint();
1030  return;
1031  }
1032 
1033  // Otherwise, thread through all the normal cleanups in scope.
1034 
1035  // Store the index at the start.
1036  llvm::ConstantInt *Index = Builder.getInt32(Dest.getDestIndex());
1037  createStoreInstBefore(Index, getNormalCleanupDestSlot(), BI);
1038 
1039  // Adjust BI to point to the first cleanup block.
1040  {
1041  EHCleanupScope &Scope =
1042  cast<EHCleanupScope>(*EHStack.find(TopCleanup));
1043  BI->setSuccessor(0, CreateNormalEntry(*this, Scope));
1044  }
1045 
1046  // Add this destination to all the scopes involved.
1047  EHScopeStack::stable_iterator I = TopCleanup;
1049  if (E.strictlyEncloses(I)) {
1050  while (true) {
1051  EHCleanupScope &Scope = cast<EHCleanupScope>(*EHStack.find(I));
1052  assert(Scope.isNormalCleanup());
1053  I = Scope.getEnclosingNormalCleanup();
1054 
1055  // If this is the last cleanup we're propagating through, tell it
1056  // that there's a resolved jump moving through it.
1057  if (!E.strictlyEncloses(I)) {
1058  Scope.addBranchAfter(Index, Dest.getBlock());
1059  break;
1060  }
1061 
1062  // Otherwise, tell the scope that there's a jump propoagating
1063  // through it. If this isn't new information, all the rest of
1064  // the work has been done before.
1065  if (!Scope.addBranchThrough(Dest.getBlock()))
1066  break;
1067  }
1068  }
1069 
1070  Builder.ClearInsertionPoint();
1071 }
1072 
1075  // If we needed a normal block for any reason, that counts.
1076  if (cast<EHCleanupScope>(*EHStack.find(C)).getNormalBlock())
1077  return true;
1078 
1079  // Check whether any enclosed cleanups were needed.
1081  I = EHStack.getInnermostNormalCleanup();
1082  I != C; ) {
1083  assert(C.strictlyEncloses(I));
1084  EHCleanupScope &S = cast<EHCleanupScope>(*EHStack.find(I));
1085  if (S.getNormalBlock()) return true;
1086  I = S.getEnclosingNormalCleanup();
1087  }
1088 
1089  return false;
1090 }
1091 
1092 static bool IsUsedAsEHCleanup(EHScopeStack &EHStack,
1094  // If we needed an EH block for any reason, that counts.
1095  if (EHStack.find(cleanup)->hasEHBranches())
1096  return true;
1097 
1098  // Check whether any enclosed cleanups were needed.
1100  i = EHStack.getInnermostEHScope(); i != cleanup; ) {
1101  assert(cleanup.strictlyEncloses(i));
1102 
1103  EHScope &scope = *EHStack.find(i);
1104  if (scope.hasEHBranches())
1105  return true;
1106 
1107  i = scope.getEnclosingEHScope();
1108  }
1109 
1110  return false;
1111 }
1112 
1116 };
1117 
1118 /// The given cleanup block is changing activation state. Configure a
1119 /// cleanup variable if necessary.
1120 ///
1121 /// It would be good if we had some way of determining if there were
1122 /// extra uses *after* the change-over point.
1126  llvm::Instruction *dominatingIP) {
1127  EHCleanupScope &Scope = cast<EHCleanupScope>(*CGF.EHStack.find(C));
1128 
1129  // We always need the flag if we're activating the cleanup in a
1130  // conditional context, because we have to assume that the current
1131  // location doesn't necessarily dominate the cleanup's code.
1132  bool isActivatedInConditional =
1133  (kind == ForActivation && CGF.isInConditionalBranch());
1134 
1135  bool needFlag = false;
1136 
1137  // Calculate whether the cleanup was used:
1138 
1139  // - as a normal cleanup
1140  if (Scope.isNormalCleanup() &&
1141  (isActivatedInConditional || IsUsedAsNormalCleanup(CGF.EHStack, C))) {
1142  Scope.setTestFlagInNormalCleanup();
1143  needFlag = true;
1144  }
1145 
1146  // - as an EH cleanup
1147  if (Scope.isEHCleanup() &&
1148  (isActivatedInConditional || IsUsedAsEHCleanup(CGF.EHStack, C))) {
1149  Scope.setTestFlagInEHCleanup();
1150  needFlag = true;
1151  }
1152 
1153  // If it hasn't yet been used as either, we're done.
1154  if (!needFlag) return;
1155 
1156  Address var = Scope.getActiveFlag();
1157  if (!var.isValid()) {
1158  var = CGF.CreateTempAlloca(CGF.Builder.getInt1Ty(), CharUnits::One(),
1159  "cleanup.isactive");
1160  Scope.setActiveFlag(var);
1161 
1162  assert(dominatingIP && "no existing variable and no dominating IP!");
1163 
1164  // Initialize to true or false depending on whether it was
1165  // active up to this point.
1166  llvm::Constant *value = CGF.Builder.getInt1(kind == ForDeactivation);
1167 
1168  // If we're in a conditional block, ignore the dominating IP and
1169  // use the outermost conditional branch.
1170  if (CGF.isInConditionalBranch()) {
1171  CGF.setBeforeOutermostConditional(value, var);
1172  } else {
1173  createStoreInstBefore(value, var, dominatingIP);
1174  }
1175  }
1176 
1177  CGF.Builder.CreateStore(CGF.Builder.getInt1(kind == ForActivation), var);
1178 }
1179 
1180 /// Activate a cleanup that was created in an inactivated state.
1182  llvm::Instruction *dominatingIP) {
1183  assert(C != EHStack.stable_end() && "activating bottom of stack?");
1184  EHCleanupScope &Scope = cast<EHCleanupScope>(*EHStack.find(C));
1185  assert(!Scope.isActive() && "double activation");
1186 
1187  SetupCleanupBlockActivation(*this, C, ForActivation, dominatingIP);
1188 
1189  Scope.setActive(true);
1190 }
1191 
1192 /// Deactive a cleanup that was created in an active state.
1194  llvm::Instruction *dominatingIP) {
1195  assert(C != EHStack.stable_end() && "deactivating bottom of stack?");
1196  EHCleanupScope &Scope = cast<EHCleanupScope>(*EHStack.find(C));
1197  assert(Scope.isActive() && "double deactivation");
1198 
1199  // If it's the top of the stack, just pop it.
1200  if (C == EHStack.stable_begin()) {
1201  // If it's a normal cleanup, we need to pretend that the
1202  // fallthrough is unreachable.
1203  CGBuilderTy::InsertPoint SavedIP = Builder.saveAndClearIP();
1204  PopCleanupBlock();
1205  Builder.restoreIP(SavedIP);
1206  return;
1207  }
1208 
1209  // Otherwise, follow the general case.
1210  SetupCleanupBlockActivation(*this, C, ForDeactivation, dominatingIP);
1211 
1212  Scope.setActive(false);
1213 }
1214 
1216  if (!NormalCleanupDest)
1217  NormalCleanupDest =
1218  CreateTempAlloca(Builder.getInt32Ty(), "cleanup.dest.slot");
1219  return Address(NormalCleanupDest, CharUnits::fromQuantity(4));
1220 }
1221 
1222 /// Emits all the code to cause the given temporary to be cleaned up.
1224  QualType TempType,
1225  Address Ptr) {
1226  pushDestroy(NormalAndEHCleanup, Ptr, TempType, destroyCXXObject,
1227  /*useEHCleanup*/ true);
1228 }
void pushTerminate()
Push a terminate handler on the stack.
Definition: CGCleanup.cpp:260
static llvm::BasicBlock * CreateNormalEntry(CodeGenFunction &CGF, EHCleanupScope &Scope)
Definition: CGCleanup.cpp:464
void ActivateCleanupBlock(EHScopeStack::stable_iterator Cleanup, llvm::Instruction *DominatingIP)
ActivateCleanupBlock - Activates an initially-inactive cleanup.
Definition: CGCleanup.cpp:1181
tooling::Replacements cleanup(const FormatStyle &Style, SourceManager &SourceMgr, FileID ID, ArrayRef< CharSourceRange > Ranges)
Clean up any erroneous/redundant code in the given Ranges in the file ID.
Definition: Format.cpp:1639
A (possibly-)qualified type.
Definition: Type.h:598
static llvm::LoadInst * createLoadInstBefore(Address addr, const Twine &name, llvm::Instruction *beforeInst)
Definition: CGCleanup.cpp:314
static void destroyOptimisticNormalEntry(CodeGenFunction &CGF, EHCleanupScope &scope)
We don't need a normal entry block for the given cleanup.
Definition: CGCleanup.cpp:563
bool isInConditionalBranch() const
isInConditionalBranch - Return true if we're currently emitting one branch or the other of a conditio...
std::pair< llvm::Value *, llvm::Value * > getComplexVal() const
getComplexVal - Return the real/imag components of this complex value.
Definition: CGValue.h:65
static stable_iterator stable_end()
Create a stable reference to the bottom of the EH stack.
Definition: EHScopeStack.h:384
llvm::AllocaInst * CreateTempAlloca(llvm::Type *Ty, const Twine &Name="tmp")
CreateTempAlloca - This creates a alloca and inserts it into the entry block.
Definition: CGExpr.cpp:69
QuantityType getQuantity() const
getQuantity - Get the raw integer representation of this quantity.
Definition: CharUnits.h:179
static llvm::SwitchInst * TransitionToCleanupSwitch(CodeGenFunction &CGF, llvm::BasicBlock *Block)
Transitions the terminator of the given exit-block of a cleanup to be a cleanup switch.
Definition: CGCleanup.cpp:362
const llvm::DataLayout & getDataLayout() const
std::unique_ptr< llvm::MemoryBuffer > Buffer
static bool needsSaving(llvm::Value *value)
Answer whether the given value needs extra work to be saved.
static void EmitCleanup(CodeGenFunction &CGF, EHScopeStack::Cleanup *Fn, EHScopeStack::Cleanup::Flags flags, Address ActiveFlag)
Definition: CGCleanup.cpp:514
A protected scope for zero-cost EH handling.
Definition: CGCleanup.h:44
A scope which attempts to handle some, possibly all, types of exceptions.
Definition: CGCleanup.h:148
A jump destination is an abstract label, branching to which may require a jump out through normal cle...
An exceptions scope which calls std::terminate if any exception reaches it.
Definition: CGCleanup.h:481
stable_iterator stabilize(iterator it) const
Translates an iterator into a stable_iterator.
Definition: CGCleanup.h:599
bool requiresLandingPad() const
Definition: CGCleanup.cpp:160
CodeGenFunction - This class organizes the per-function state that is used while generating LLVM code...
ForActivation_t
Definition: CGCleanup.cpp:1113
Denotes a cleanup that should run when a scope is exited using exceptional control flow (a throw stat...
Definition: EHScopeStack.h:81
bool hasEHBranches() const
Definition: CGCleanup.h:132
static const EHPersonality & get(CodeGenModule &CGM, const FunctionDecl *FD)
A metaprogramming class for ensuring that a value will dominate an arbitrary position in a function...
Definition: EHScopeStack.h:66
class EHCatchScope * pushCatch(unsigned NumHandlers)
Push a set of catch handlers on the stack.
Definition: CGCleanup.cpp:252
iterator begin() const
Returns an iterator pointing to the innermost EH scope.
Definition: CGCleanup.h:568
unsigned FixupDepth
The number of fixups required by enclosing scopes (not including this one).
Definition: CGCleanup.h:265
BranchFixup & getBranchFixup(unsigned I)
Definition: EHScopeStack.h:403
CharUnits - This is an opaque type for sizes expressed in character units.
Definition: CharUnits.h:38
bool isObviouslyBranchWithoutCleanups(JumpDest Dest) const
isObviouslyBranchWithoutCleanups - Return true if a branch to the specified destination obviously has...
Definition: CGCleanup.cpp:972
Scope - A scope is a transient data structure that is used while parsing the program.
Definition: Scope.h:39
void initFullExprCleanup()
Set up the last cleaup that was pushed as a conditional full-expression cleanup.
Definition: CGCleanup.cpp:285
A stack of scopes which respond to exceptions, including cleanups and catch blocks.
Definition: EHScopeStack.h:100
llvm::BasicBlock * createBasicBlock(const Twine &name="", llvm::Function *parent=nullptr, llvm::BasicBlock *before=nullptr)
createBasicBlock - Create an LLVM basic block.
Denotes a cleanup that should run when a scope is exited using normal control flow (falling off the e...
Definition: EHScopeStack.h:85
void popFilter()
Pops an exceptions filter off the stack.
Definition: CGCleanup.cpp:243
bool isValid() const
Definition: Address.h:36
detail::InMemoryDirectory::const_iterator I
static bool IsUsedAsEHCleanup(EHScopeStack &EHStack, EHScopeStack::stable_iterator cleanup)
Definition: CGCleanup.cpp:1092
static size_t getSizeForNumHandlers(unsigned N)
Definition: CGCleanup.h:178
iterator find(stable_iterator save) const
Turn a stable reference to a scope depth into a unstable pointer to the EH stack. ...
Definition: CGCleanup.h:592
static CharUnits One()
One - Construct a CharUnits quantity of one.
Definition: CharUnits.h:58
std::pair< llvm::Value *, llvm::Value * > ComplexPairTy
unsigned getNumBranchFixups() const
Definition: EHScopeStack.h:402
static void createStoreInstBefore(llvm::Value *value, Address addr, llvm::Instruction *beforeInst)
Definition: CGCleanup.cpp:308
RValue - This trivial value class is used to represent the result of an expression that is evaluated...
Definition: CGValue.h:38
static void ResolveAllBranchFixups(CodeGenFunction &CGF, llvm::SwitchInst *Switch, llvm::BasicBlock *CleanupEntry)
All the branch fixups on the EH stack have propagated out past the outermost normal cleanup; resolve ...
Definition: CGCleanup.cpp:324
llvm::BranchInst * InitialBranch
The initial branch of the fixup.
Definition: EHScopeStack.h:53
Address CreateDefaultAlignTempAlloca(llvm::Type *Ty, const Twine &Name="tmp")
CreateDefaultAlignedTempAlloca - This creates an alloca with the default ABI alignment of the given L...
Definition: CGExpr.cpp:78
llvm::Value * getPointer() const
Definition: Address.h:38
bool empty() const
Determines whether the exception-scopes stack is empty.
Definition: EHScopeStack.h:345
static size_t getSizeForCleanupSize(size_t Size)
Gets the size required for a lazy cleanup scope with the given cleanup-data requirements.
Definition: CGCleanup.h:280
void clearFixups()
Clears the branch-fixups list.
Definition: EHScopeStack.h:415
static Address invalid()
Definition: Address.h:35
bool isAggregate() const
Definition: CGValue.h:53
llvm::AllocaInst * NormalCleanupDest
i32s containing the indexes of the cleanup destinations.
llvm::BasicBlock * getBlock() const
EHScopeStack::stable_iterator getScopeDepth() const
static CharUnits fromQuantity(QuantityType Quantity)
fromQuantity - Construct a CharUnits quantity from a raw integer type.
Definition: CharUnits.h:63
EHScopeStack::stable_iterator getEnclosingEHScope() const
Definition: CGCleanup.h:138
stable_iterator stable_begin() const
Create a stable reference to the top of the EH stack.
Definition: EHScopeStack.h:379
llvm::AllocaInst * ActiveFlag
An optional i1 variable indicating whether this cleanup has been activated yet.
Definition: CGCleanup.h:246
bool containsOnlyLifetimeMarkers(stable_iterator Old) const
Definition: CGCleanup.cpp:149
void ResolveBranchFixups(llvm::BasicBlock *Target)
Definition: CGCleanup.cpp:382
bool usesFuncletPads() const
Does this personality use landingpads or the family of pad instructions designed to form funclets...
Definition: CGCleanup.h:632
EHCleanupScope(bool isNormal, bool isEH, bool isActive, unsigned cleanupSize, unsigned fixupDepth, EHScopeStack::stable_iterator enclosingNormal, EHScopeStack::stable_iterator enclosingEH)
Definition: CGCleanup.h:288
llvm::BasicBlock * OptimisticBranchBlock
The block containing the terminator which needs to be modified into a switch if this fixup is resolve...
Definition: EHScopeStack.h:41
void popCleanup()
Pops a cleanup scope off the stack. This is private to CGCleanup.cpp.
Definition: CGCleanup.cpp:210
The l-value was considered opaque, so the alignment was determined from a type.
bool HaveInsertPoint() const
HaveInsertPoint - True if an insertion point is defined.
llvm::BasicBlock * Destination
The ultimate destination of the branch.
Definition: EHScopeStack.h:47
Kind
A saved depth on the scope stack.
Definition: EHScopeStack.h:107
Represents a C++ temporary.
Definition: ExprCXX.h:1088
llvm::BasicBlock * getUnreachableBlock()
void setBeforeOutermostConditional(llvm::Value *value, Address addr)
static OMPLinearClause * Create(const ASTContext &C, SourceLocation StartLoc, SourceLocation LParenLoc, OpenMPLinearClauseKind Modifier, SourceLocation ModifierLoc, SourceLocation ColonLoc, SourceLocation EndLoc, ArrayRef< Expr * > VL, ArrayRef< Expr * > PL, ArrayRef< Expr * > IL, Expr *Step, Expr *CalcStep, Stmt *PreInit, Expr *PostUpdate)
Creates clause with a list of variables VL and a linear step Step.
void DeactivateCleanupBlock(EHScopeStack::stable_iterator Cleanup, llvm::Instruction *DominatingIP)
DeactivateCleanupBlock - Deactivates the given cleanup block.
Definition: CGCleanup.cpp:1193
void EmitCXXTemporary(const CXXTemporary *Temporary, QualType TempType, Address Ptr)
Emits all the code to cause the given temporary to be cleaned up.
Definition: CGCleanup.cpp:1223
An aligned address.
Definition: Address.h:25
unsigned DestinationIndex
The destination index value.
Definition: EHScopeStack.h:50
virtual void Emit(CodeGenFunction &CGF, Flags flags)=0
Emit the cleanup.
static size_t getSizeForNumFilters(unsigned numFilters)
Definition: CGCleanup.h:458
static bool IsUsedAsNormalCleanup(EHScopeStack &EHStack, EHScopeStack::stable_iterator C)
Definition: CGCleanup.cpp:1073
static void ForwardPrebranchedFallthrough(llvm::BasicBlock *Exit, llvm::BasicBlock *From, llvm::BasicBlock *To)
Definition: CGCleanup.cpp:539
CharUnits getAlignment() const
Return the alignment of this pointer.
Definition: Address.h:67
class EHFilterScope * pushFilter(unsigned NumFilters)
Push an exceptions filter on the stack.
Definition: CGCleanup.cpp:235
llvm::Value * getAggregatePointer() const
Definition: CGValue.h:75
bool encloses(stable_iterator I) const
Returns true if this scope encloses I.
Definition: EHScopeStack.h:124
bool isScalar() const
Definition: CGValue.h:51
static RValue getComplex(llvm::Value *V1, llvm::Value *V2)
Definition: CGValue.h:92
void popNullFixups()
Pops lazily-removed fixups from the end of the list.
Definition: CGCleanup.cpp:271
llvm::Value * getScalarVal() const
getScalarVal() - Return the Value* of this scalar value.
Definition: CGValue.h:58
Address CreateStructGEP(Address Addr, unsigned Index, CharUnits Offset, const llvm::Twine &Name="")
Definition: CGBuilder.h:183
static llvm::BasicBlock * SimplifyCleanupEntry(CodeGenFunction &CGF, llvm::BasicBlock *Entry)
Attempts to reduce a cleanup's entry block to a fallthrough.
Definition: CGCleanup.cpp:480
llvm::LoadInst * CreateLoad(Address Addr, const llvm::Twine &Name="")
Definition: CGBuilder.h:70
Header for data within LifetimeExtendedCleanupStack.
detail::InMemoryDirectory::const_iterator E
llvm::StoreInst * CreateStore(llvm::Value *Val, Address Addr, bool IsVolatile=false)
Definition: CGBuilder.h:113
static void SetupCleanupBlockActivation(CodeGenFunction &CGF, EHScopeStack::stable_iterator C, ForActivation_t kind, llvm::Instruction *dominatingIP)
The given cleanup block is changing activation state.
Definition: CGCleanup.cpp:1123
bool isComplex() const
Definition: CGValue.h:52
void EmitBlock(llvm::BasicBlock *BB, bool IsFinished=false)
EmitBlock - Emit the given block.
Definition: CGStmt.cpp:397
llvm::BasicBlock * getNormalBlock() const
Definition: CGCleanup.h:313
BoundNodesTreeBuilder *const Builder
stable_iterator getInnermostActiveNormalCleanup() const
Definition: CGCleanup.cpp:175
void PopCleanupBlocks(EHScopeStack::stable_iterator OldCleanupStackSize)
Takes the old cleanup stack size and emits the cleanup blocks that have been added.
Definition: CGCleanup.cpp:421
unsigned kind
All of the diagnostics that can be emitted by the frontend.
Definition: DiagnosticIDs.h:43
Address getAggregateAddress() const
getAggregateAddr() - Return the Value* of the address of the aggregate.
Definition: CGValue.h:70
bool hasNormalCleanups() const
Determines whether there are any normal cleanups on the stack.
Definition: EHScopeStack.h:350
unsigned getNumFilters() const
Definition: CGCleanup.h:462
stable_iterator getInnermostEHScope() const
Definition: EHScopeStack.h:361
bool strictlyEncloses(stable_iterator I) const
Returns true if this scope strictly encloses I: that is, if it encloses I and is not I...
Definition: EHScopeStack.h:130
stable_iterator getInnermostNormalCleanup() const
Returns the innermost normal cleanup on the stack, or stable_end() if there are no normal cleanups...
Definition: EHScopeStack.h:356
An exceptions scope which filters exceptions thrown through it.
Definition: CGCleanup.h:439
static RValue get(llvm::Value *V)
Definition: CGValue.h:85
void EmitBranchThroughCleanup(JumpDest Dest)
EmitBranchThroughCleanup - Emit a branch from the current insert block through the normal cleanup han...
Definition: CGCleanup.cpp:997
static RValue getAggregate(Address addr, bool isVolatile=false)
Definition: CGValue.h:106
Information for lazily generating a cleanup.
Definition: EHScopeStack.h:147
A non-stable pointer into the scope stack.
Definition: CGCleanup.h:504
void PopCleanupBlock(bool FallThroughIsBranchThrough=false)
PopCleanupBlock - Will pop the cleanup entry on the stack and process all branch fixups.
Definition: CGCleanup.cpp:603