clang  8.0.0svn
CGException.cpp
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1 //===--- CGException.cpp - Emit LLVM Code for C++ exceptions ----*- C++ -*-===//
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 contains code dealing with C++ exception related code generation.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "CodeGenFunction.h"
15 #include "CGCXXABI.h"
16 #include "CGCleanup.h"
17 #include "CGObjCRuntime.h"
18 #include "ConstantEmitter.h"
19 #include "TargetInfo.h"
20 #include "clang/AST/Mangle.h"
21 #include "clang/AST/StmtCXX.h"
22 #include "clang/AST/StmtObjC.h"
23 #include "clang/AST/StmtVisitor.h"
25 #include "llvm/IR/CallSite.h"
26 #include "llvm/IR/Intrinsics.h"
27 #include "llvm/IR/IntrinsicInst.h"
28 #include "llvm/Support/SaveAndRestore.h"
29 
30 using namespace clang;
31 using namespace CodeGen;
32 
33 static llvm::Constant *getFreeExceptionFn(CodeGenModule &CGM) {
34  // void __cxa_free_exception(void *thrown_exception);
35 
36  llvm::FunctionType *FTy =
37  llvm::FunctionType::get(CGM.VoidTy, CGM.Int8PtrTy, /*IsVarArgs=*/false);
38 
39  return CGM.CreateRuntimeFunction(FTy, "__cxa_free_exception");
40 }
41 
42 static llvm::Constant *getUnexpectedFn(CodeGenModule &CGM) {
43  // void __cxa_call_unexpected(void *thrown_exception);
44 
45  llvm::FunctionType *FTy =
46  llvm::FunctionType::get(CGM.VoidTy, CGM.Int8PtrTy, /*IsVarArgs=*/false);
47 
48  return CGM.CreateRuntimeFunction(FTy, "__cxa_call_unexpected");
49 }
50 
51 llvm::Constant *CodeGenModule::getTerminateFn() {
52  // void __terminate();
53 
54  llvm::FunctionType *FTy =
55  llvm::FunctionType::get(VoidTy, /*IsVarArgs=*/false);
56 
57  StringRef name;
58 
59  // In C++, use std::terminate().
60  if (getLangOpts().CPlusPlus &&
61  getTarget().getCXXABI().isItaniumFamily()) {
62  name = "_ZSt9terminatev";
63  } else if (getLangOpts().CPlusPlus &&
64  getTarget().getCXXABI().isMicrosoft()) {
65  if (getLangOpts().isCompatibleWithMSVC(LangOptions::MSVC2015))
66  name = "__std_terminate";
67  else
68  name = "?terminate@@YAXXZ";
69  } else if (getLangOpts().ObjC1 &&
71  name = "objc_terminate";
72  else
73  name = "abort";
74  return CreateRuntimeFunction(FTy, name);
75 }
76 
77 static llvm::Constant *getCatchallRethrowFn(CodeGenModule &CGM,
78  StringRef Name) {
79  llvm::FunctionType *FTy =
80  llvm::FunctionType::get(CGM.VoidTy, CGM.Int8PtrTy, /*IsVarArgs=*/false);
81 
82  return CGM.CreateRuntimeFunction(FTy, Name);
83 }
84 
85 const EHPersonality EHPersonality::GNU_C = { "__gcc_personality_v0", nullptr };
86 const EHPersonality
87 EHPersonality::GNU_C_SJLJ = { "__gcc_personality_sj0", nullptr };
88 const EHPersonality
89 EHPersonality::GNU_C_SEH = { "__gcc_personality_seh0", nullptr };
90 const EHPersonality
91 EHPersonality::NeXT_ObjC = { "__objc_personality_v0", nullptr };
92 const EHPersonality
93 EHPersonality::GNU_CPlusPlus = { "__gxx_personality_v0", nullptr };
94 const EHPersonality
95 EHPersonality::GNU_CPlusPlus_SJLJ = { "__gxx_personality_sj0", nullptr };
96 const EHPersonality
97 EHPersonality::GNU_CPlusPlus_SEH = { "__gxx_personality_seh0", nullptr };
98 const EHPersonality
99 EHPersonality::GNU_ObjC = {"__gnu_objc_personality_v0", "objc_exception_throw"};
100 const EHPersonality
101 EHPersonality::GNU_ObjC_SJLJ = {"__gnu_objc_personality_sj0", "objc_exception_throw"};
102 const EHPersonality
103 EHPersonality::GNU_ObjC_SEH = {"__gnu_objc_personality_seh0", "objc_exception_throw"};
104 const EHPersonality
105 EHPersonality::GNU_ObjCXX = { "__gnustep_objcxx_personality_v0", nullptr };
106 const EHPersonality
107 EHPersonality::GNUstep_ObjC = { "__gnustep_objc_personality_v0", nullptr };
108 const EHPersonality
109 EHPersonality::MSVC_except_handler = { "_except_handler3", nullptr };
110 const EHPersonality
111 EHPersonality::MSVC_C_specific_handler = { "__C_specific_handler", nullptr };
112 const EHPersonality
113 EHPersonality::MSVC_CxxFrameHandler3 = { "__CxxFrameHandler3", nullptr };
114 const EHPersonality
115 EHPersonality::GNU_Wasm_CPlusPlus = { "__gxx_wasm_personality_v0", nullptr };
116 
117 static const EHPersonality &getCPersonality(const TargetInfo &Target,
118  const LangOptions &L) {
119  const llvm::Triple &T = Target.getTriple();
120  if (T.isWindowsMSVCEnvironment())
121  return EHPersonality::MSVC_CxxFrameHandler3;
122  if (L.SjLjExceptions)
124  if (L.DWARFExceptions)
125  return EHPersonality::GNU_C;
126  if (L.SEHExceptions)
128  return EHPersonality::GNU_C;
129 }
130 
131 static const EHPersonality &getObjCPersonality(const TargetInfo &Target,
132  const LangOptions &L) {
133  const llvm::Triple &T = Target.getTriple();
134  if (T.isWindowsMSVCEnvironment())
135  return EHPersonality::MSVC_CxxFrameHandler3;
136 
137  switch (L.ObjCRuntime.getKind()) {
139  return getCPersonality(Target, L);
140  case ObjCRuntime::MacOSX:
141  case ObjCRuntime::iOS:
145  if (L.ObjCRuntime.getVersion() >= VersionTuple(1, 7))
146  return EHPersonality::GNUstep_ObjC;
147  LLVM_FALLTHROUGH;
148  case ObjCRuntime::GCC:
149  case ObjCRuntime::ObjFW:
150  if (L.SjLjExceptions)
152  if (L.SEHExceptions)
155  }
156  llvm_unreachable("bad runtime kind");
157 }
158 
159 static const EHPersonality &getCXXPersonality(const TargetInfo &Target,
160  const LangOptions &L) {
161  const llvm::Triple &T = Target.getTriple();
162  if (T.isWindowsMSVCEnvironment())
163  return EHPersonality::MSVC_CxxFrameHandler3;
164  if (L.SjLjExceptions)
166  if (L.DWARFExceptions)
168  if (L.SEHExceptions)
170  // Wasm EH is a non-MVP feature for now.
171  if (Target.hasFeature("exception-handling") &&
172  (T.getArch() == llvm::Triple::wasm32 ||
173  T.getArch() == llvm::Triple::wasm64))
176 }
177 
178 /// Determines the personality function to use when both C++
179 /// and Objective-C exceptions are being caught.
180 static const EHPersonality &getObjCXXPersonality(const TargetInfo &Target,
181  const LangOptions &L) {
182  if (Target.getTriple().isWindowsMSVCEnvironment())
183  return EHPersonality::MSVC_CxxFrameHandler3;
184 
185  switch (L.ObjCRuntime.getKind()) {
186  // In the fragile ABI, just use C++ exception handling and hope
187  // they're not doing crazy exception mixing.
189  return getCXXPersonality(Target, L);
190 
191  // The ObjC personality defers to the C++ personality for non-ObjC
192  // handlers. Unlike the C++ case, we use the same personality
193  // function on targets using (backend-driven) SJLJ EH.
194  case ObjCRuntime::MacOSX:
195  case ObjCRuntime::iOS:
197  return getObjCPersonality(Target, L);
198 
201 
202  // The GCC runtime's personality function inherently doesn't support
203  // mixed EH. Use the ObjC personality just to avoid returning null.
204  case ObjCRuntime::GCC:
205  case ObjCRuntime::ObjFW:
206  return getObjCPersonality(Target, L);
207  }
208  llvm_unreachable("bad runtime kind");
209 }
210 
211 static const EHPersonality &getSEHPersonalityMSVC(const llvm::Triple &T) {
212  if (T.getArch() == llvm::Triple::x86)
213  return EHPersonality::MSVC_except_handler;
215 }
216 
218  const FunctionDecl *FD) {
219  const llvm::Triple &T = CGM.getTarget().getTriple();
220  const LangOptions &L = CGM.getLangOpts();
221  const TargetInfo &Target = CGM.getTarget();
222 
223  // Functions using SEH get an SEH personality.
224  if (FD && FD->usesSEHTry())
225  return getSEHPersonalityMSVC(T);
226 
227  if (L.ObjC1)
228  return L.CPlusPlus ? getObjCXXPersonality(Target, L)
229  : getObjCPersonality(Target, L);
230  return L.CPlusPlus ? getCXXPersonality(Target, L)
231  : getCPersonality(Target, L);
232 }
233 
235  const auto *FD = CGF.CurCodeDecl;
236  // For outlined finallys and filters, use the SEH personality in case they
237  // contain more SEH. This mostly only affects finallys. Filters could
238  // hypothetically use gnu statement expressions to sneak in nested SEH.
239  FD = FD ? FD : CGF.CurSEHParent;
240  return get(CGF.CGM, dyn_cast_or_null<FunctionDecl>(FD));
241 }
242 
243 static llvm::Constant *getPersonalityFn(CodeGenModule &CGM,
244  const EHPersonality &Personality) {
245  return CGM.CreateRuntimeFunction(llvm::FunctionType::get(CGM.Int32Ty, true),
246  Personality.PersonalityFn,
247  llvm::AttributeList(), /*Local=*/true);
248 }
249 
250 static llvm::Constant *getOpaquePersonalityFn(CodeGenModule &CGM,
251  const EHPersonality &Personality) {
252  llvm::Constant *Fn = getPersonalityFn(CGM, Personality);
253  return llvm::ConstantExpr::getBitCast(Fn, CGM.Int8PtrTy);
254 }
255 
256 /// Check whether a landingpad instruction only uses C++ features.
257 static bool LandingPadHasOnlyCXXUses(llvm::LandingPadInst *LPI) {
258  for (unsigned I = 0, E = LPI->getNumClauses(); I != E; ++I) {
259  // Look for something that would've been returned by the ObjC
260  // runtime's GetEHType() method.
261  llvm::Value *Val = LPI->getClause(I)->stripPointerCasts();
262  if (LPI->isCatch(I)) {
263  // Check if the catch value has the ObjC prefix.
264  if (llvm::GlobalVariable *GV = dyn_cast<llvm::GlobalVariable>(Val))
265  // ObjC EH selector entries are always global variables with
266  // names starting like this.
267  if (GV->getName().startswith("OBJC_EHTYPE"))
268  return false;
269  } else {
270  // Check if any of the filter values have the ObjC prefix.
271  llvm::Constant *CVal = cast<llvm::Constant>(Val);
272  for (llvm::User::op_iterator
273  II = CVal->op_begin(), IE = CVal->op_end(); II != IE; ++II) {
274  if (llvm::GlobalVariable *GV =
275  cast<llvm::GlobalVariable>((*II)->stripPointerCasts()))
276  // ObjC EH selector entries are always global variables with
277  // names starting like this.
278  if (GV->getName().startswith("OBJC_EHTYPE"))
279  return false;
280  }
281  }
282  }
283  return true;
284 }
285 
286 /// Check whether a personality function could reasonably be swapped
287 /// for a C++ personality function.
288 static bool PersonalityHasOnlyCXXUses(llvm::Constant *Fn) {
289  for (llvm::User *U : Fn->users()) {
290  // Conditionally white-list bitcasts.
291  if (llvm::ConstantExpr *CE = dyn_cast<llvm::ConstantExpr>(U)) {
292  if (CE->getOpcode() != llvm::Instruction::BitCast) return false;
293  if (!PersonalityHasOnlyCXXUses(CE))
294  return false;
295  continue;
296  }
297 
298  // Otherwise it must be a function.
299  llvm::Function *F = dyn_cast<llvm::Function>(U);
300  if (!F) return false;
301 
302  for (auto BB = F->begin(), E = F->end(); BB != E; ++BB) {
303  if (BB->isLandingPad())
304  if (!LandingPadHasOnlyCXXUses(BB->getLandingPadInst()))
305  return false;
306  }
307  }
308 
309  return true;
310 }
311 
312 /// Try to use the C++ personality function in ObjC++. Not doing this
313 /// can cause some incompatibilities with gcc, which is more
314 /// aggressive about only using the ObjC++ personality in a function
315 /// when it really needs it.
316 void CodeGenModule::SimplifyPersonality() {
317  // If we're not in ObjC++ -fexceptions, there's nothing to do.
318  if (!LangOpts.CPlusPlus || !LangOpts.ObjC1 || !LangOpts.Exceptions)
319  return;
320 
321  // Both the problem this endeavors to fix and the way the logic
322  // above works is specific to the NeXT runtime.
323  if (!LangOpts.ObjCRuntime.isNeXTFamily())
324  return;
325 
326  const EHPersonality &ObjCXX = EHPersonality::get(*this, /*FD=*/nullptr);
327  const EHPersonality &CXX = getCXXPersonality(getTarget(), LangOpts);
328  if (&ObjCXX == &CXX)
329  return;
330 
331  assert(std::strcmp(ObjCXX.PersonalityFn, CXX.PersonalityFn) != 0 &&
332  "Different EHPersonalities using the same personality function.");
333 
334  llvm::Function *Fn = getModule().getFunction(ObjCXX.PersonalityFn);
335 
336  // Nothing to do if it's unused.
337  if (!Fn || Fn->use_empty()) return;
338 
339  // Can't do the optimization if it has non-C++ uses.
340  if (!PersonalityHasOnlyCXXUses(Fn)) return;
341 
342  // Create the C++ personality function and kill off the old
343  // function.
344  llvm::Constant *CXXFn = getPersonalityFn(*this, CXX);
345 
346  // This can happen if the user is screwing with us.
347  if (Fn->getType() != CXXFn->getType()) return;
348 
349  Fn->replaceAllUsesWith(CXXFn);
350  Fn->eraseFromParent();
351 }
352 
353 /// Returns the value to inject into a selector to indicate the
354 /// presence of a catch-all.
355 static llvm::Constant *getCatchAllValue(CodeGenFunction &CGF) {
356  // Possibly we should use @llvm.eh.catch.all.value here.
357  return llvm::ConstantPointerNull::get(CGF.Int8PtrTy);
358 }
359 
360 namespace {
361  /// A cleanup to free the exception object if its initialization
362  /// throws.
363  struct FreeException final : EHScopeStack::Cleanup {
364  llvm::Value *exn;
365  FreeException(llvm::Value *exn) : exn(exn) {}
366  void Emit(CodeGenFunction &CGF, Flags flags) override {
368  }
369  };
370 } // end anonymous namespace
371 
372 // Emits an exception expression into the given location. This
373 // differs from EmitAnyExprToMem only in that, if a final copy-ctor
374 // call is required, an exception within that copy ctor causes
375 // std::terminate to be invoked.
377  // Make sure the exception object is cleaned up if there's an
378  // exception during initialization.
379  pushFullExprCleanup<FreeException>(EHCleanup, addr.getPointer());
380  EHScopeStack::stable_iterator cleanup = EHStack.stable_begin();
381 
382  // __cxa_allocate_exception returns a void*; we need to cast this
383  // to the appropriate type for the object.
384  llvm::Type *ty = ConvertTypeForMem(e->getType())->getPointerTo();
385  Address typedAddr = Builder.CreateBitCast(addr, ty);
386 
387  // FIXME: this isn't quite right! If there's a final unelided call
388  // to a copy constructor, then according to [except.terminate]p1 we
389  // must call std::terminate() if that constructor throws, because
390  // technically that copy occurs after the exception expression is
391  // evaluated but before the exception is caught. But the best way
392  // to handle that is to teach EmitAggExpr to do the final copy
393  // differently if it can't be elided.
394  EmitAnyExprToMem(e, typedAddr, e->getType().getQualifiers(),
395  /*IsInit*/ true);
396 
397  // Deactivate the cleanup block.
398  DeactivateCleanupBlock(cleanup,
399  cast<llvm::Instruction>(typedAddr.getPointer()));
400 }
401 
403  if (!ExceptionSlot)
404  ExceptionSlot = CreateTempAlloca(Int8PtrTy, "exn.slot");
405  return Address(ExceptionSlot, getPointerAlign());
406 }
407 
409  if (!EHSelectorSlot)
410  EHSelectorSlot = CreateTempAlloca(Int32Ty, "ehselector.slot");
411  return Address(EHSelectorSlot, CharUnits::fromQuantity(4));
412 }
413 
415  return Builder.CreateLoad(getExceptionSlot(), "exn");
416 }
417 
419  return Builder.CreateLoad(getEHSelectorSlot(), "sel");
420 }
421 
423  bool KeepInsertionPoint) {
424  if (const Expr *SubExpr = E->getSubExpr()) {
425  QualType ThrowType = SubExpr->getType();
426  if (ThrowType->isObjCObjectPointerType()) {
427  const Stmt *ThrowStmt = E->getSubExpr();
428  const ObjCAtThrowStmt S(E->getExprLoc(), const_cast<Stmt *>(ThrowStmt));
429  CGM.getObjCRuntime().EmitThrowStmt(*this, S, false);
430  } else {
431  CGM.getCXXABI().emitThrow(*this, E);
432  }
433  } else {
434  CGM.getCXXABI().emitRethrow(*this, /*isNoReturn=*/true);
435  }
436 
437  // throw is an expression, and the expression emitters expect us
438  // to leave ourselves at a valid insertion point.
439  if (KeepInsertionPoint)
440  EmitBlock(createBasicBlock("throw.cont"));
441 }
442 
444  if (!CGM.getLangOpts().CXXExceptions)
445  return;
446 
447  const FunctionDecl* FD = dyn_cast_or_null<FunctionDecl>(D);
448  if (!FD) {
449  // Check if CapturedDecl is nothrow and create terminate scope for it.
450  if (const CapturedDecl* CD = dyn_cast_or_null<CapturedDecl>(D)) {
451  if (CD->isNothrow())
452  EHStack.pushTerminate();
453  }
454  return;
455  }
456  const FunctionProtoType *Proto = FD->getType()->getAs<FunctionProtoType>();
457  if (!Proto)
458  return;
459 
461  if (isNoexceptExceptionSpec(EST) && Proto->canThrow() == CT_Cannot) {
462  // noexcept functions are simple terminate scopes.
463  EHStack.pushTerminate();
464  } else if (EST == EST_Dynamic || EST == EST_DynamicNone) {
465  // TODO: Revisit exception specifications for the MS ABI. There is a way to
466  // encode these in an object file but MSVC doesn't do anything with it.
467  if (getTarget().getCXXABI().isMicrosoft())
468  return;
469  unsigned NumExceptions = Proto->getNumExceptions();
470  EHFilterScope *Filter = EHStack.pushFilter(NumExceptions);
471 
472  for (unsigned I = 0; I != NumExceptions; ++I) {
473  QualType Ty = Proto->getExceptionType(I);
474  QualType ExceptType = Ty.getNonReferenceType().getUnqualifiedType();
475  llvm::Value *EHType = CGM.GetAddrOfRTTIDescriptor(ExceptType,
476  /*ForEH=*/true);
477  Filter->setFilter(I, EHType);
478  }
479  }
480 }
481 
482 /// Emit the dispatch block for a filter scope if necessary.
484  EHFilterScope &filterScope) {
485  llvm::BasicBlock *dispatchBlock = filterScope.getCachedEHDispatchBlock();
486  if (!dispatchBlock) return;
487  if (dispatchBlock->use_empty()) {
488  delete dispatchBlock;
489  return;
490  }
491 
492  CGF.EmitBlockAfterUses(dispatchBlock);
493 
494  // If this isn't a catch-all filter, we need to check whether we got
495  // here because the filter triggered.
496  if (filterScope.getNumFilters()) {
497  // Load the selector value.
498  llvm::Value *selector = CGF.getSelectorFromSlot();
499  llvm::BasicBlock *unexpectedBB = CGF.createBasicBlock("ehspec.unexpected");
500 
501  llvm::Value *zero = CGF.Builder.getInt32(0);
502  llvm::Value *failsFilter =
503  CGF.Builder.CreateICmpSLT(selector, zero, "ehspec.fails");
504  CGF.Builder.CreateCondBr(failsFilter, unexpectedBB,
505  CGF.getEHResumeBlock(false));
506 
507  CGF.EmitBlock(unexpectedBB);
508  }
509 
510  // Call __cxa_call_unexpected. This doesn't need to be an invoke
511  // because __cxa_call_unexpected magically filters exceptions
512  // according to the last landing pad the exception was thrown
513  // into. Seriously.
514  llvm::Value *exn = CGF.getExceptionFromSlot();
515  CGF.EmitRuntimeCall(getUnexpectedFn(CGF.CGM), exn)
516  ->setDoesNotReturn();
517  CGF.Builder.CreateUnreachable();
518 }
519 
521  if (!CGM.getLangOpts().CXXExceptions)
522  return;
523 
524  const FunctionDecl* FD = dyn_cast_or_null<FunctionDecl>(D);
525  if (!FD) {
526  // Check if CapturedDecl is nothrow and pop terminate scope for it.
527  if (const CapturedDecl* CD = dyn_cast_or_null<CapturedDecl>(D)) {
528  if (CD->isNothrow())
529  EHStack.popTerminate();
530  }
531  return;
532  }
533  const FunctionProtoType *Proto = FD->getType()->getAs<FunctionProtoType>();
534  if (!Proto)
535  return;
536 
538  if (isNoexceptExceptionSpec(EST) && Proto->canThrow() == CT_Cannot) {
539  EHStack.popTerminate();
540  } else if (EST == EST_Dynamic || EST == EST_DynamicNone) {
541  // TODO: Revisit exception specifications for the MS ABI. There is a way to
542  // encode these in an object file but MSVC doesn't do anything with it.
543  if (getTarget().getCXXABI().isMicrosoft())
544  return;
545  EHFilterScope &filterScope = cast<EHFilterScope>(*EHStack.begin());
546  emitFilterDispatchBlock(*this, filterScope);
547  EHStack.popFilter();
548  }
549 }
550 
552  EnterCXXTryStmt(S);
553  EmitStmt(S.getTryBlock());
554  ExitCXXTryStmt(S);
555 }
556 
557 void CodeGenFunction::EnterCXXTryStmt(const CXXTryStmt &S, bool IsFnTryBlock) {
558  unsigned NumHandlers = S.getNumHandlers();
559  EHCatchScope *CatchScope = EHStack.pushCatch(NumHandlers);
560 
561  for (unsigned I = 0; I != NumHandlers; ++I) {
562  const CXXCatchStmt *C = S.getHandler(I);
563 
564  llvm::BasicBlock *Handler = createBasicBlock("catch");
565  if (C->getExceptionDecl()) {
566  // FIXME: Dropping the reference type on the type into makes it
567  // impossible to correctly implement catch-by-reference
568  // semantics for pointers. Unfortunately, this is what all
569  // existing compilers do, and it's not clear that the standard
570  // personality routine is capable of doing this right. See C++ DR 388:
571  // http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#388
572  Qualifiers CaughtTypeQuals;
573  QualType CaughtType = CGM.getContext().getUnqualifiedArrayType(
574  C->getCaughtType().getNonReferenceType(), CaughtTypeQuals);
575 
576  CatchTypeInfo TypeInfo{nullptr, 0};
577  if (CaughtType->isObjCObjectPointerType())
578  TypeInfo.RTTI = CGM.getObjCRuntime().GetEHType(CaughtType);
579  else
580  TypeInfo = CGM.getCXXABI().getAddrOfCXXCatchHandlerType(
581  CaughtType, C->getCaughtType());
582  CatchScope->setHandler(I, TypeInfo, Handler);
583  } else {
584  // No exception decl indicates '...', a catch-all.
585  CatchScope->setHandler(I, CGM.getCXXABI().getCatchAllTypeInfo(), Handler);
586  }
587  }
588 }
589 
590 llvm::BasicBlock *
592  if (EHPersonality::get(*this).usesFuncletPads())
593  return getFuncletEHDispatchBlock(si);
594 
595  // The dispatch block for the end of the scope chain is a block that
596  // just resumes unwinding.
597  if (si == EHStack.stable_end())
598  return getEHResumeBlock(true);
599 
600  // Otherwise, we should look at the actual scope.
601  EHScope &scope = *EHStack.find(si);
602 
603  llvm::BasicBlock *dispatchBlock = scope.getCachedEHDispatchBlock();
604  if (!dispatchBlock) {
605  switch (scope.getKind()) {
606  case EHScope::Catch: {
607  // Apply a special case to a single catch-all.
608  EHCatchScope &catchScope = cast<EHCatchScope>(scope);
609  if (catchScope.getNumHandlers() == 1 &&
610  catchScope.getHandler(0).isCatchAll()) {
611  dispatchBlock = catchScope.getHandler(0).Block;
612 
613  // Otherwise, make a dispatch block.
614  } else {
615  dispatchBlock = createBasicBlock("catch.dispatch");
616  }
617  break;
618  }
619 
620  case EHScope::Cleanup:
621  dispatchBlock = createBasicBlock("ehcleanup");
622  break;
623 
624  case EHScope::Filter:
625  dispatchBlock = createBasicBlock("filter.dispatch");
626  break;
627 
628  case EHScope::Terminate:
629  dispatchBlock = getTerminateHandler();
630  break;
631 
632  case EHScope::PadEnd:
633  llvm_unreachable("PadEnd unnecessary for Itanium!");
634  }
635  scope.setCachedEHDispatchBlock(dispatchBlock);
636  }
637  return dispatchBlock;
638 }
639 
640 llvm::BasicBlock *
642  // Returning nullptr indicates that the previous dispatch block should unwind
643  // to caller.
644  if (SI == EHStack.stable_end())
645  return nullptr;
646 
647  // Otherwise, we should look at the actual scope.
648  EHScope &EHS = *EHStack.find(SI);
649 
650  llvm::BasicBlock *DispatchBlock = EHS.getCachedEHDispatchBlock();
651  if (DispatchBlock)
652  return DispatchBlock;
653 
654  if (EHS.getKind() == EHScope::Terminate)
655  DispatchBlock = getTerminateFunclet();
656  else
657  DispatchBlock = createBasicBlock();
658  CGBuilderTy Builder(*this, DispatchBlock);
659 
660  switch (EHS.getKind()) {
661  case EHScope::Catch:
662  DispatchBlock->setName("catch.dispatch");
663  break;
664 
665  case EHScope::Cleanup:
666  DispatchBlock->setName("ehcleanup");
667  break;
668 
669  case EHScope::Filter:
670  llvm_unreachable("exception specifications not handled yet!");
671 
672  case EHScope::Terminate:
673  DispatchBlock->setName("terminate");
674  break;
675 
676  case EHScope::PadEnd:
677  llvm_unreachable("PadEnd dispatch block missing!");
678  }
679  EHS.setCachedEHDispatchBlock(DispatchBlock);
680  return DispatchBlock;
681 }
682 
683 /// Check whether this is a non-EH scope, i.e. a scope which doesn't
684 /// affect exception handling. Currently, the only non-EH scopes are
685 /// normal-only cleanup scopes.
686 static bool isNonEHScope(const EHScope &S) {
687  switch (S.getKind()) {
688  case EHScope::Cleanup:
689  return !cast<EHCleanupScope>(S).isEHCleanup();
690  case EHScope::Filter:
691  case EHScope::Catch:
692  case EHScope::Terminate:
693  case EHScope::PadEnd:
694  return false;
695  }
696 
697  llvm_unreachable("Invalid EHScope Kind!");
698 }
699 
701  assert(EHStack.requiresLandingPad());
702  assert(!EHStack.empty());
703 
704  // If exceptions are disabled and SEH is not in use, then there is no invoke
705  // destination. SEH "works" even if exceptions are off. In practice, this
706  // means that C++ destructors and other EH cleanups don't run, which is
707  // consistent with MSVC's behavior.
708  const LangOptions &LO = CGM.getLangOpts();
709  if (!LO.Exceptions) {
710  if (!LO.Borland && !LO.MicrosoftExt)
711  return nullptr;
712  if (!currentFunctionUsesSEHTry())
713  return nullptr;
714  }
715 
716  // CUDA device code doesn't have exceptions.
717  if (LO.CUDA && LO.CUDAIsDevice)
718  return nullptr;
719 
720  // Check the innermost scope for a cached landing pad. If this is
721  // a non-EH cleanup, we'll check enclosing scopes in EmitLandingPad.
722  llvm::BasicBlock *LP = EHStack.begin()->getCachedLandingPad();
723  if (LP) return LP;
724 
725  const EHPersonality &Personality = EHPersonality::get(*this);
726 
727  if (!CurFn->hasPersonalityFn())
728  CurFn->setPersonalityFn(getOpaquePersonalityFn(CGM, Personality));
729 
730  if (Personality.usesFuncletPads()) {
731  // We don't need separate landing pads in the funclet model.
732  LP = getEHDispatchBlock(EHStack.getInnermostEHScope());
733  } else {
734  // Build the landing pad for this scope.
735  LP = EmitLandingPad();
736  }
737 
738  assert(LP);
739 
740  // Cache the landing pad on the innermost scope. If this is a
741  // non-EH scope, cache the landing pad on the enclosing scope, too.
742  for (EHScopeStack::iterator ir = EHStack.begin(); true; ++ir) {
743  ir->setCachedLandingPad(LP);
744  if (!isNonEHScope(*ir)) break;
745  }
746 
747  return LP;
748 }
749 
750 llvm::BasicBlock *CodeGenFunction::EmitLandingPad() {
751  assert(EHStack.requiresLandingPad());
752 
753  EHScope &innermostEHScope = *EHStack.find(EHStack.getInnermostEHScope());
754  switch (innermostEHScope.getKind()) {
755  case EHScope::Terminate:
756  return getTerminateLandingPad();
757 
758  case EHScope::PadEnd:
759  llvm_unreachable("PadEnd unnecessary for Itanium!");
760 
761  case EHScope::Catch:
762  case EHScope::Cleanup:
763  case EHScope::Filter:
764  if (llvm::BasicBlock *lpad = innermostEHScope.getCachedLandingPad())
765  return lpad;
766  }
767 
768  // Save the current IR generation state.
769  CGBuilderTy::InsertPoint savedIP = Builder.saveAndClearIP();
770  auto DL = ApplyDebugLocation::CreateDefaultArtificial(*this, CurEHLocation);
771 
772  // Create and configure the landing pad.
773  llvm::BasicBlock *lpad = createBasicBlock("lpad");
774  EmitBlock(lpad);
775 
776  llvm::LandingPadInst *LPadInst =
777  Builder.CreateLandingPad(llvm::StructType::get(Int8PtrTy, Int32Ty), 0);
778 
779  llvm::Value *LPadExn = Builder.CreateExtractValue(LPadInst, 0);
780  Builder.CreateStore(LPadExn, getExceptionSlot());
781  llvm::Value *LPadSel = Builder.CreateExtractValue(LPadInst, 1);
782  Builder.CreateStore(LPadSel, getEHSelectorSlot());
783 
784  // Save the exception pointer. It's safe to use a single exception
785  // pointer per function because EH cleanups can never have nested
786  // try/catches.
787  // Build the landingpad instruction.
788 
789  // Accumulate all the handlers in scope.
790  bool hasCatchAll = false;
791  bool hasCleanup = false;
792  bool hasFilter = false;
793  SmallVector<llvm::Value*, 4> filterTypes;
794  llvm::SmallPtrSet<llvm::Value*, 4> catchTypes;
795  for (EHScopeStack::iterator I = EHStack.begin(), E = EHStack.end(); I != E;
796  ++I) {
797 
798  switch (I->getKind()) {
799  case EHScope::Cleanup:
800  // If we have a cleanup, remember that.
801  hasCleanup = (hasCleanup || cast<EHCleanupScope>(*I).isEHCleanup());
802  continue;
803 
804  case EHScope::Filter: {
805  assert(I.next() == EHStack.end() && "EH filter is not end of EH stack");
806  assert(!hasCatchAll && "EH filter reached after catch-all");
807 
808  // Filter scopes get added to the landingpad in weird ways.
809  EHFilterScope &filter = cast<EHFilterScope>(*I);
810  hasFilter = true;
811 
812  // Add all the filter values.
813  for (unsigned i = 0, e = filter.getNumFilters(); i != e; ++i)
814  filterTypes.push_back(filter.getFilter(i));
815  goto done;
816  }
817 
818  case EHScope::Terminate:
819  // Terminate scopes are basically catch-alls.
820  assert(!hasCatchAll);
821  hasCatchAll = true;
822  goto done;
823 
824  case EHScope::Catch:
825  break;
826 
827  case EHScope::PadEnd:
828  llvm_unreachable("PadEnd unnecessary for Itanium!");
829  }
830 
831  EHCatchScope &catchScope = cast<EHCatchScope>(*I);
832  for (unsigned hi = 0, he = catchScope.getNumHandlers(); hi != he; ++hi) {
833  EHCatchScope::Handler handler = catchScope.getHandler(hi);
834  assert(handler.Type.Flags == 0 &&
835  "landingpads do not support catch handler flags");
836 
837  // If this is a catch-all, register that and abort.
838  if (!handler.Type.RTTI) {
839  assert(!hasCatchAll);
840  hasCatchAll = true;
841  goto done;
842  }
843 
844  // Check whether we already have a handler for this type.
845  if (catchTypes.insert(handler.Type.RTTI).second)
846  // If not, add it directly to the landingpad.
847  LPadInst->addClause(handler.Type.RTTI);
848  }
849  }
850 
851  done:
852  // If we have a catch-all, add null to the landingpad.
853  assert(!(hasCatchAll && hasFilter));
854  if (hasCatchAll) {
855  LPadInst->addClause(getCatchAllValue(*this));
856 
857  // If we have an EH filter, we need to add those handlers in the
858  // right place in the landingpad, which is to say, at the end.
859  } else if (hasFilter) {
860  // Create a filter expression: a constant array indicating which filter
861  // types there are. The personality routine only lands here if the filter
862  // doesn't match.
864  llvm::ArrayType *AType =
865  llvm::ArrayType::get(!filterTypes.empty() ?
866  filterTypes[0]->getType() : Int8PtrTy,
867  filterTypes.size());
868 
869  for (unsigned i = 0, e = filterTypes.size(); i != e; ++i)
870  Filters.push_back(cast<llvm::Constant>(filterTypes[i]));
871  llvm::Constant *FilterArray = llvm::ConstantArray::get(AType, Filters);
872  LPadInst->addClause(FilterArray);
873 
874  // Also check whether we need a cleanup.
875  if (hasCleanup)
876  LPadInst->setCleanup(true);
877 
878  // Otherwise, signal that we at least have cleanups.
879  } else if (hasCleanup) {
880  LPadInst->setCleanup(true);
881  }
882 
883  assert((LPadInst->getNumClauses() > 0 || LPadInst->isCleanup()) &&
884  "landingpad instruction has no clauses!");
885 
886  // Tell the backend how to generate the landing pad.
887  Builder.CreateBr(getEHDispatchBlock(EHStack.getInnermostEHScope()));
888 
889  // Restore the old IR generation state.
890  Builder.restoreIP(savedIP);
891 
892  return lpad;
893 }
894 
895 static void emitCatchPadBlock(CodeGenFunction &CGF, EHCatchScope &CatchScope) {
896  llvm::BasicBlock *DispatchBlock = CatchScope.getCachedEHDispatchBlock();
897  assert(DispatchBlock);
898 
899  CGBuilderTy::InsertPoint SavedIP = CGF.Builder.saveIP();
900  CGF.EmitBlockAfterUses(DispatchBlock);
901 
902  llvm::Value *ParentPad = CGF.CurrentFuncletPad;
903  if (!ParentPad)
904  ParentPad = llvm::ConstantTokenNone::get(CGF.getLLVMContext());
905  llvm::BasicBlock *UnwindBB =
906  CGF.getEHDispatchBlock(CatchScope.getEnclosingEHScope());
907 
908  unsigned NumHandlers = CatchScope.getNumHandlers();
909  llvm::CatchSwitchInst *CatchSwitch =
910  CGF.Builder.CreateCatchSwitch(ParentPad, UnwindBB, NumHandlers);
911 
912  // Test against each of the exception types we claim to catch.
913  for (unsigned I = 0; I < NumHandlers; ++I) {
914  const EHCatchScope::Handler &Handler = CatchScope.getHandler(I);
915 
916  CatchTypeInfo TypeInfo = Handler.Type;
917  if (!TypeInfo.RTTI)
918  TypeInfo.RTTI = llvm::Constant::getNullValue(CGF.VoidPtrTy);
919 
920  CGF.Builder.SetInsertPoint(Handler.Block);
921 
922  if (EHPersonality::get(CGF).isMSVCXXPersonality()) {
923  CGF.Builder.CreateCatchPad(
924  CatchSwitch, {TypeInfo.RTTI, CGF.Builder.getInt32(TypeInfo.Flags),
925  llvm::Constant::getNullValue(CGF.VoidPtrTy)});
926  } else {
927  CGF.Builder.CreateCatchPad(CatchSwitch, {TypeInfo.RTTI});
928  }
929 
930  CatchSwitch->addHandler(Handler.Block);
931  }
932  CGF.Builder.restoreIP(SavedIP);
933 }
934 
935 // Wasm uses Windows-style EH instructions, but it merges all catch clauses into
936 // one big catchpad, within which we use Itanium's landingpad-style selector
937 // comparison instructions.
939  EHCatchScope &CatchScope) {
940  llvm::BasicBlock *DispatchBlock = CatchScope.getCachedEHDispatchBlock();
941  assert(DispatchBlock);
942 
943  CGBuilderTy::InsertPoint SavedIP = CGF.Builder.saveIP();
944  CGF.EmitBlockAfterUses(DispatchBlock);
945 
946  llvm::Value *ParentPad = CGF.CurrentFuncletPad;
947  if (!ParentPad)
948  ParentPad = llvm::ConstantTokenNone::get(CGF.getLLVMContext());
949  llvm::BasicBlock *UnwindBB =
950  CGF.getEHDispatchBlock(CatchScope.getEnclosingEHScope());
951 
952  unsigned NumHandlers = CatchScope.getNumHandlers();
953  llvm::CatchSwitchInst *CatchSwitch =
954  CGF.Builder.CreateCatchSwitch(ParentPad, UnwindBB, NumHandlers);
955 
956  // We don't use a landingpad instruction, so generate intrinsic calls to
957  // provide exception and selector values.
958  llvm::BasicBlock *WasmCatchStartBlock = CGF.createBasicBlock("catch.start");
959  CatchSwitch->addHandler(WasmCatchStartBlock);
960  CGF.EmitBlockAfterUses(WasmCatchStartBlock);
961 
962  // Create a catchpad instruction.
964  for (unsigned I = 0, E = NumHandlers; I < E; ++I) {
965  const EHCatchScope::Handler &Handler = CatchScope.getHandler(I);
966  CatchTypeInfo TypeInfo = Handler.Type;
967  if (!TypeInfo.RTTI)
968  TypeInfo.RTTI = llvm::Constant::getNullValue(CGF.VoidPtrTy);
969  CatchTypes.push_back(TypeInfo.RTTI);
970  }
971  auto *CPI = CGF.Builder.CreateCatchPad(CatchSwitch, CatchTypes);
972 
973  // Create calls to wasm.get.exception and wasm.get.ehselector intrinsics.
974  // Before they are lowered appropriately later, they provide values for the
975  // exception and selector.
976  llvm::Value *GetExnFn =
977  CGF.CGM.getIntrinsic(llvm::Intrinsic::wasm_get_exception);
978  llvm::Value *GetSelectorFn =
979  CGF.CGM.getIntrinsic(llvm::Intrinsic::wasm_get_ehselector);
980  llvm::CallInst *Exn = CGF.Builder.CreateCall(GetExnFn, CPI);
981  CGF.Builder.CreateStore(Exn, CGF.getExceptionSlot());
982  llvm::CallInst *Selector = CGF.Builder.CreateCall(GetSelectorFn, CPI);
983 
984  llvm::Value *TypeIDFn = CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_typeid_for);
985 
986  // If there's only a single catch-all, branch directly to its handler.
987  if (CatchScope.getNumHandlers() == 1 &&
988  CatchScope.getHandler(0).isCatchAll()) {
989  CGF.Builder.CreateBr(CatchScope.getHandler(0).Block);
990  CGF.Builder.restoreIP(SavedIP);
991  return;
992  }
993 
994  // Test against each of the exception types we claim to catch.
995  for (unsigned I = 0, E = NumHandlers;; ++I) {
996  assert(I < E && "ran off end of handlers!");
997  const EHCatchScope::Handler &Handler = CatchScope.getHandler(I);
998  CatchTypeInfo TypeInfo = Handler.Type;
999  if (!TypeInfo.RTTI)
1000  TypeInfo.RTTI = llvm::Constant::getNullValue(CGF.VoidPtrTy);
1001 
1002  // Figure out the next block.
1003  llvm::BasicBlock *NextBlock;
1004 
1005  bool EmitNextBlock = false, NextIsEnd = false;
1006 
1007  // If this is the last handler, we're at the end, and the next block is a
1008  // block that contains a call to the rethrow function, so we can unwind to
1009  // the enclosing EH scope. The call itself will be generated later.
1010  if (I + 1 == E) {
1011  NextBlock = CGF.createBasicBlock("rethrow");
1012  EmitNextBlock = true;
1013  NextIsEnd = true;
1014 
1015  // If the next handler is a catch-all, we're at the end, and the
1016  // next block is that handler.
1017  } else if (CatchScope.getHandler(I + 1).isCatchAll()) {
1018  NextBlock = CatchScope.getHandler(I + 1).Block;
1019  NextIsEnd = true;
1020 
1021  // Otherwise, we're not at the end and we need a new block.
1022  } else {
1023  NextBlock = CGF.createBasicBlock("catch.fallthrough");
1024  EmitNextBlock = true;
1025  }
1026 
1027  // Figure out the catch type's index in the LSDA's type table.
1028  llvm::CallInst *TypeIndex = CGF.Builder.CreateCall(TypeIDFn, TypeInfo.RTTI);
1029  TypeIndex->setDoesNotThrow();
1030 
1031  llvm::Value *MatchesTypeIndex =
1032  CGF.Builder.CreateICmpEQ(Selector, TypeIndex, "matches");
1033  CGF.Builder.CreateCondBr(MatchesTypeIndex, Handler.Block, NextBlock);
1034 
1035  if (EmitNextBlock)
1036  CGF.EmitBlock(NextBlock);
1037  if (NextIsEnd)
1038  break;
1039  }
1040 
1041  CGF.Builder.restoreIP(SavedIP);
1042 }
1043 
1044 /// Emit the structure of the dispatch block for the given catch scope.
1045 /// It is an invariant that the dispatch block already exists.
1047  EHCatchScope &catchScope) {
1048  if (EHPersonality::get(CGF).isWasmPersonality())
1049  return emitWasmCatchPadBlock(CGF, catchScope);
1050  if (EHPersonality::get(CGF).usesFuncletPads())
1051  return emitCatchPadBlock(CGF, catchScope);
1052 
1053  llvm::BasicBlock *dispatchBlock = catchScope.getCachedEHDispatchBlock();
1054  assert(dispatchBlock);
1055 
1056  // If there's only a single catch-all, getEHDispatchBlock returned
1057  // that catch-all as the dispatch block.
1058  if (catchScope.getNumHandlers() == 1 &&
1059  catchScope.getHandler(0).isCatchAll()) {
1060  assert(dispatchBlock == catchScope.getHandler(0).Block);
1061  return;
1062  }
1063 
1064  CGBuilderTy::InsertPoint savedIP = CGF.Builder.saveIP();
1065  CGF.EmitBlockAfterUses(dispatchBlock);
1066 
1067  // Select the right handler.
1068  llvm::Value *llvm_eh_typeid_for =
1069  CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_typeid_for);
1070 
1071  // Load the selector value.
1072  llvm::Value *selector = CGF.getSelectorFromSlot();
1073 
1074  // Test against each of the exception types we claim to catch.
1075  for (unsigned i = 0, e = catchScope.getNumHandlers(); ; ++i) {
1076  assert(i < e && "ran off end of handlers!");
1077  const EHCatchScope::Handler &handler = catchScope.getHandler(i);
1078 
1079  llvm::Value *typeValue = handler.Type.RTTI;
1080  assert(handler.Type.Flags == 0 &&
1081  "landingpads do not support catch handler flags");
1082  assert(typeValue && "fell into catch-all case!");
1083  typeValue = CGF.Builder.CreateBitCast(typeValue, CGF.Int8PtrTy);
1084 
1085  // Figure out the next block.
1086  bool nextIsEnd;
1087  llvm::BasicBlock *nextBlock;
1088 
1089  // If this is the last handler, we're at the end, and the next
1090  // block is the block for the enclosing EH scope.
1091  if (i + 1 == e) {
1092  nextBlock = CGF.getEHDispatchBlock(catchScope.getEnclosingEHScope());
1093  nextIsEnd = true;
1094 
1095  // If the next handler is a catch-all, we're at the end, and the
1096  // next block is that handler.
1097  } else if (catchScope.getHandler(i+1).isCatchAll()) {
1098  nextBlock = catchScope.getHandler(i+1).Block;
1099  nextIsEnd = true;
1100 
1101  // Otherwise, we're not at the end and we need a new block.
1102  } else {
1103  nextBlock = CGF.createBasicBlock("catch.fallthrough");
1104  nextIsEnd = false;
1105  }
1106 
1107  // Figure out the catch type's index in the LSDA's type table.
1108  llvm::CallInst *typeIndex =
1109  CGF.Builder.CreateCall(llvm_eh_typeid_for, typeValue);
1110  typeIndex->setDoesNotThrow();
1111 
1112  llvm::Value *matchesTypeIndex =
1113  CGF.Builder.CreateICmpEQ(selector, typeIndex, "matches");
1114  CGF.Builder.CreateCondBr(matchesTypeIndex, handler.Block, nextBlock);
1115 
1116  // If the next handler is a catch-all, we're completely done.
1117  if (nextIsEnd) {
1118  CGF.Builder.restoreIP(savedIP);
1119  return;
1120  }
1121  // Otherwise we need to emit and continue at that block.
1122  CGF.EmitBlock(nextBlock);
1123  }
1124 }
1125 
1127  EHCatchScope &catchScope = cast<EHCatchScope>(*EHStack.begin());
1128  if (catchScope.hasEHBranches())
1129  emitCatchDispatchBlock(*this, catchScope);
1130  EHStack.popCatch();
1131 }
1132 
1133 void CodeGenFunction::ExitCXXTryStmt(const CXXTryStmt &S, bool IsFnTryBlock) {
1134  unsigned NumHandlers = S.getNumHandlers();
1135  EHCatchScope &CatchScope = cast<EHCatchScope>(*EHStack.begin());
1136  assert(CatchScope.getNumHandlers() == NumHandlers);
1137  llvm::BasicBlock *DispatchBlock = CatchScope.getCachedEHDispatchBlock();
1138 
1139  // If the catch was not required, bail out now.
1140  if (!CatchScope.hasEHBranches()) {
1141  CatchScope.clearHandlerBlocks();
1142  EHStack.popCatch();
1143  return;
1144  }
1145 
1146  // Emit the structure of the EH dispatch for this catch.
1147  emitCatchDispatchBlock(*this, CatchScope);
1148 
1149  // Copy the handler blocks off before we pop the EH stack. Emitting
1150  // the handlers might scribble on this memory.
1152  CatchScope.begin(), CatchScope.begin() + NumHandlers);
1153 
1154  EHStack.popCatch();
1155 
1156  // The fall-through block.
1157  llvm::BasicBlock *ContBB = createBasicBlock("try.cont");
1158 
1159  // We just emitted the body of the try; jump to the continue block.
1160  if (HaveInsertPoint())
1161  Builder.CreateBr(ContBB);
1162 
1163  // Determine if we need an implicit rethrow for all these catch handlers;
1164  // see the comment below.
1165  bool doImplicitRethrow = false;
1166  if (IsFnTryBlock)
1167  doImplicitRethrow = isa<CXXDestructorDecl>(CurCodeDecl) ||
1168  isa<CXXConstructorDecl>(CurCodeDecl);
1169 
1170  // Wasm uses Windows-style EH instructions, but merges all catch clauses into
1171  // one big catchpad. So we save the old funclet pad here before we traverse
1172  // each catch handler.
1173  SaveAndRestore<llvm::Instruction *> RestoreCurrentFuncletPad(
1174  CurrentFuncletPad);
1175  llvm::BasicBlock *WasmCatchStartBlock = nullptr;
1176  if (EHPersonality::get(*this).isWasmPersonality()) {
1177  auto *CatchSwitch =
1178  cast<llvm::CatchSwitchInst>(DispatchBlock->getFirstNonPHI());
1179  WasmCatchStartBlock = CatchSwitch->hasUnwindDest()
1180  ? CatchSwitch->getSuccessor(1)
1181  : CatchSwitch->getSuccessor(0);
1182  auto *CPI = cast<llvm::CatchPadInst>(WasmCatchStartBlock->getFirstNonPHI());
1183  CurrentFuncletPad = CPI;
1184  }
1185 
1186  // Perversely, we emit the handlers backwards precisely because we
1187  // want them to appear in source order. In all of these cases, the
1188  // catch block will have exactly one predecessor, which will be a
1189  // particular block in the catch dispatch. However, in the case of
1190  // a catch-all, one of the dispatch blocks will branch to two
1191  // different handlers, and EmitBlockAfterUses will cause the second
1192  // handler to be moved before the first.
1193  bool HasCatchAll = false;
1194  for (unsigned I = NumHandlers; I != 0; --I) {
1195  HasCatchAll |= Handlers[I - 1].isCatchAll();
1196  llvm::BasicBlock *CatchBlock = Handlers[I-1].Block;
1197  EmitBlockAfterUses(CatchBlock);
1198 
1199  // Catch the exception if this isn't a catch-all.
1200  const CXXCatchStmt *C = S.getHandler(I-1);
1201 
1202  // Enter a cleanup scope, including the catch variable and the
1203  // end-catch.
1204  RunCleanupsScope CatchScope(*this);
1205 
1206  // Initialize the catch variable and set up the cleanups.
1207  SaveAndRestore<llvm::Instruction *> RestoreCurrentFuncletPad(
1208  CurrentFuncletPad);
1209  CGM.getCXXABI().emitBeginCatch(*this, C);
1210 
1211  // Emit the PGO counter increment.
1212  incrementProfileCounter(C);
1213 
1214  // Perform the body of the catch.
1215  EmitStmt(C->getHandlerBlock());
1216 
1217  // [except.handle]p11:
1218  // The currently handled exception is rethrown if control
1219  // reaches the end of a handler of the function-try-block of a
1220  // constructor or destructor.
1221 
1222  // It is important that we only do this on fallthrough and not on
1223  // return. Note that it's illegal to put a return in a
1224  // constructor function-try-block's catch handler (p14), so this
1225  // really only applies to destructors.
1226  if (doImplicitRethrow && HaveInsertPoint()) {
1227  CGM.getCXXABI().emitRethrow(*this, /*isNoReturn*/false);
1228  Builder.CreateUnreachable();
1229  Builder.ClearInsertionPoint();
1230  }
1231 
1232  // Fall out through the catch cleanups.
1233  CatchScope.ForceCleanup();
1234 
1235  // Branch out of the try.
1236  if (HaveInsertPoint())
1237  Builder.CreateBr(ContBB);
1238  }
1239 
1240  // Because in wasm we merge all catch clauses into one big catchpad, in case
1241  // none of the types in catch handlers matches after we test against each of
1242  // them, we should unwind to the next EH enclosing scope. We generate a call
1243  // to rethrow function here to do that.
1244  if (EHPersonality::get(*this).isWasmPersonality() && !HasCatchAll) {
1245  assert(WasmCatchStartBlock);
1246  // Navigate for the "rethrow" block we created in emitWasmCatchPadBlock().
1247  // Wasm uses landingpad-style conditional branches to compare selectors, so
1248  // we follow the false destination for each of the cond branches to reach
1249  // the rethrow block.
1250  llvm::BasicBlock *RethrowBlock = WasmCatchStartBlock;
1251  while (llvm::TerminatorInst *TI = RethrowBlock->getTerminator()) {
1252  auto *BI = cast<llvm::BranchInst>(TI);
1253  assert(BI->isConditional());
1254  RethrowBlock = BI->getSuccessor(1);
1255  }
1256  assert(RethrowBlock != WasmCatchStartBlock && RethrowBlock->empty());
1257  Builder.SetInsertPoint(RethrowBlock);
1258  CGM.getCXXABI().emitRethrow(*this, /*isNoReturn=*/true);
1259  }
1260 
1261  EmitBlock(ContBB);
1262  incrementProfileCounter(&S);
1263 }
1264 
1265 namespace {
1266  struct CallEndCatchForFinally final : EHScopeStack::Cleanup {
1267  llvm::Value *ForEHVar;
1268  llvm::Value *EndCatchFn;
1269  CallEndCatchForFinally(llvm::Value *ForEHVar, llvm::Value *EndCatchFn)
1270  : ForEHVar(ForEHVar), EndCatchFn(EndCatchFn) {}
1271 
1272  void Emit(CodeGenFunction &CGF, Flags flags) override {
1273  llvm::BasicBlock *EndCatchBB = CGF.createBasicBlock("finally.endcatch");
1274  llvm::BasicBlock *CleanupContBB =
1275  CGF.createBasicBlock("finally.cleanup.cont");
1276 
1277  llvm::Value *ShouldEndCatch =
1278  CGF.Builder.CreateFlagLoad(ForEHVar, "finally.endcatch");
1279  CGF.Builder.CreateCondBr(ShouldEndCatch, EndCatchBB, CleanupContBB);
1280  CGF.EmitBlock(EndCatchBB);
1281  CGF.EmitRuntimeCallOrInvoke(EndCatchFn); // catch-all, so might throw
1282  CGF.EmitBlock(CleanupContBB);
1283  }
1284  };
1285 
1286  struct PerformFinally final : EHScopeStack::Cleanup {
1287  const Stmt *Body;
1288  llvm::Value *ForEHVar;
1289  llvm::Value *EndCatchFn;
1290  llvm::Value *RethrowFn;
1291  llvm::Value *SavedExnVar;
1292 
1293  PerformFinally(const Stmt *Body, llvm::Value *ForEHVar,
1294  llvm::Value *EndCatchFn,
1295  llvm::Value *RethrowFn, llvm::Value *SavedExnVar)
1296  : Body(Body), ForEHVar(ForEHVar), EndCatchFn(EndCatchFn),
1297  RethrowFn(RethrowFn), SavedExnVar(SavedExnVar) {}
1298 
1299  void Emit(CodeGenFunction &CGF, Flags flags) override {
1300  // Enter a cleanup to call the end-catch function if one was provided.
1301  if (EndCatchFn)
1302  CGF.EHStack.pushCleanup<CallEndCatchForFinally>(NormalAndEHCleanup,
1303  ForEHVar, EndCatchFn);
1304 
1305  // Save the current cleanup destination in case there are
1306  // cleanups in the finally block.
1307  llvm::Value *SavedCleanupDest =
1309  "cleanup.dest.saved");
1310 
1311  // Emit the finally block.
1312  CGF.EmitStmt(Body);
1313 
1314  // If the end of the finally is reachable, check whether this was
1315  // for EH. If so, rethrow.
1316  if (CGF.HaveInsertPoint()) {
1317  llvm::BasicBlock *RethrowBB = CGF.createBasicBlock("finally.rethrow");
1318  llvm::BasicBlock *ContBB = CGF.createBasicBlock("finally.cont");
1319 
1320  llvm::Value *ShouldRethrow =
1321  CGF.Builder.CreateFlagLoad(ForEHVar, "finally.shouldthrow");
1322  CGF.Builder.CreateCondBr(ShouldRethrow, RethrowBB, ContBB);
1323 
1324  CGF.EmitBlock(RethrowBB);
1325  if (SavedExnVar) {
1326  CGF.EmitRuntimeCallOrInvoke(RethrowFn,
1327  CGF.Builder.CreateAlignedLoad(SavedExnVar, CGF.getPointerAlign()));
1328  } else {
1329  CGF.EmitRuntimeCallOrInvoke(RethrowFn);
1330  }
1331  CGF.Builder.CreateUnreachable();
1332 
1333  CGF.EmitBlock(ContBB);
1334 
1335  // Restore the cleanup destination.
1336  CGF.Builder.CreateStore(SavedCleanupDest,
1337  CGF.getNormalCleanupDestSlot());
1338  }
1339 
1340  // Leave the end-catch cleanup. As an optimization, pretend that
1341  // the fallthrough path was inaccessible; we've dynamically proven
1342  // that we're not in the EH case along that path.
1343  if (EndCatchFn) {
1344  CGBuilderTy::InsertPoint SavedIP = CGF.Builder.saveAndClearIP();
1345  CGF.PopCleanupBlock();
1346  CGF.Builder.restoreIP(SavedIP);
1347  }
1348 
1349  // Now make sure we actually have an insertion point or the
1350  // cleanup gods will hate us.
1351  CGF.EnsureInsertPoint();
1352  }
1353  };
1354 } // end anonymous namespace
1355 
1356 /// Enters a finally block for an implementation using zero-cost
1357 /// exceptions. This is mostly general, but hard-codes some
1358 /// language/ABI-specific behavior in the catch-all sections.
1360  const Stmt *body,
1361  llvm::Constant *beginCatchFn,
1362  llvm::Constant *endCatchFn,
1363  llvm::Constant *rethrowFn) {
1364  assert((beginCatchFn != nullptr) == (endCatchFn != nullptr) &&
1365  "begin/end catch functions not paired");
1366  assert(rethrowFn && "rethrow function is required");
1367 
1368  BeginCatchFn = beginCatchFn;
1369 
1370  // The rethrow function has one of the following two types:
1371  // void (*)()
1372  // void (*)(void*)
1373  // In the latter case we need to pass it the exception object.
1374  // But we can't use the exception slot because the @finally might
1375  // have a landing pad (which would overwrite the exception slot).
1376  llvm::FunctionType *rethrowFnTy =
1377  cast<llvm::FunctionType>(
1378  cast<llvm::PointerType>(rethrowFn->getType())->getElementType());
1379  SavedExnVar = nullptr;
1380  if (rethrowFnTy->getNumParams())
1381  SavedExnVar = CGF.CreateTempAlloca(CGF.Int8PtrTy, "finally.exn");
1382 
1383  // A finally block is a statement which must be executed on any edge
1384  // out of a given scope. Unlike a cleanup, the finally block may
1385  // contain arbitrary control flow leading out of itself. In
1386  // addition, finally blocks should always be executed, even if there
1387  // are no catch handlers higher on the stack. Therefore, we
1388  // surround the protected scope with a combination of a normal
1389  // cleanup (to catch attempts to break out of the block via normal
1390  // control flow) and an EH catch-all (semantically "outside" any try
1391  // statement to which the finally block might have been attached).
1392  // The finally block itself is generated in the context of a cleanup
1393  // which conditionally leaves the catch-all.
1394 
1395  // Jump destination for performing the finally block on an exception
1396  // edge. We'll never actually reach this block, so unreachable is
1397  // fine.
1398  RethrowDest = CGF.getJumpDestInCurrentScope(CGF.getUnreachableBlock());
1399 
1400  // Whether the finally block is being executed for EH purposes.
1401  ForEHVar = CGF.CreateTempAlloca(CGF.Builder.getInt1Ty(), "finally.for-eh");
1402  CGF.Builder.CreateFlagStore(false, ForEHVar);
1403 
1404  // Enter a normal cleanup which will perform the @finally block.
1405  CGF.EHStack.pushCleanup<PerformFinally>(NormalCleanup, body,
1406  ForEHVar, endCatchFn,
1407  rethrowFn, SavedExnVar);
1408 
1409  // Enter a catch-all scope.
1410  llvm::BasicBlock *catchBB = CGF.createBasicBlock("finally.catchall");
1411  EHCatchScope *catchScope = CGF.EHStack.pushCatch(1);
1412  catchScope->setCatchAllHandler(0, catchBB);
1413 }
1414 
1416  // Leave the finally catch-all.
1417  EHCatchScope &catchScope = cast<EHCatchScope>(*CGF.EHStack.begin());
1418  llvm::BasicBlock *catchBB = catchScope.getHandler(0).Block;
1419 
1420  CGF.popCatchScope();
1421 
1422  // If there are any references to the catch-all block, emit it.
1423  if (catchBB->use_empty()) {
1424  delete catchBB;
1425  } else {
1426  CGBuilderTy::InsertPoint savedIP = CGF.Builder.saveAndClearIP();
1427  CGF.EmitBlock(catchBB);
1428 
1429  llvm::Value *exn = nullptr;
1430 
1431  // If there's a begin-catch function, call it.
1432  if (BeginCatchFn) {
1433  exn = CGF.getExceptionFromSlot();
1434  CGF.EmitNounwindRuntimeCall(BeginCatchFn, exn);
1435  }
1436 
1437  // If we need to remember the exception pointer to rethrow later, do so.
1438  if (SavedExnVar) {
1439  if (!exn) exn = CGF.getExceptionFromSlot();
1440  CGF.Builder.CreateAlignedStore(exn, SavedExnVar, CGF.getPointerAlign());
1441  }
1442 
1443  // Tell the cleanups in the finally block that we're do this for EH.
1444  CGF.Builder.CreateFlagStore(true, ForEHVar);
1445 
1446  // Thread a jump through the finally cleanup.
1447  CGF.EmitBranchThroughCleanup(RethrowDest);
1448 
1449  CGF.Builder.restoreIP(savedIP);
1450  }
1451 
1452  // Finally, leave the @finally cleanup.
1453  CGF.PopCleanupBlock();
1454 }
1455 
1457  if (TerminateLandingPad)
1458  return TerminateLandingPad;
1459 
1460  CGBuilderTy::InsertPoint SavedIP = Builder.saveAndClearIP();
1461 
1462  // This will get inserted at the end of the function.
1463  TerminateLandingPad = createBasicBlock("terminate.lpad");
1464  Builder.SetInsertPoint(TerminateLandingPad);
1465 
1466  // Tell the backend that this is a landing pad.
1467  const EHPersonality &Personality = EHPersonality::get(*this);
1468 
1469  if (!CurFn->hasPersonalityFn())
1470  CurFn->setPersonalityFn(getOpaquePersonalityFn(CGM, Personality));
1471 
1472  llvm::LandingPadInst *LPadInst =
1473  Builder.CreateLandingPad(llvm::StructType::get(Int8PtrTy, Int32Ty), 0);
1474  LPadInst->addClause(getCatchAllValue(*this));
1475 
1476  llvm::Value *Exn = nullptr;
1477  if (getLangOpts().CPlusPlus)
1478  Exn = Builder.CreateExtractValue(LPadInst, 0);
1479  llvm::CallInst *terminateCall =
1480  CGM.getCXXABI().emitTerminateForUnexpectedException(*this, Exn);
1481  terminateCall->setDoesNotReturn();
1482  Builder.CreateUnreachable();
1483 
1484  // Restore the saved insertion state.
1485  Builder.restoreIP(SavedIP);
1486 
1487  return TerminateLandingPad;
1488 }
1489 
1491  if (TerminateHandler)
1492  return TerminateHandler;
1493 
1494  // Set up the terminate handler. This block is inserted at the very
1495  // end of the function by FinishFunction.
1496  TerminateHandler = createBasicBlock("terminate.handler");
1497  CGBuilderTy::InsertPoint SavedIP = Builder.saveAndClearIP();
1498  Builder.SetInsertPoint(TerminateHandler);
1499 
1500  llvm::Value *Exn = nullptr;
1501  if (getLangOpts().CPlusPlus)
1502  Exn = getExceptionFromSlot();
1503  llvm::CallInst *terminateCall =
1504  CGM.getCXXABI().emitTerminateForUnexpectedException(*this, Exn);
1505  terminateCall->setDoesNotReturn();
1506  Builder.CreateUnreachable();
1507 
1508  // Restore the saved insertion state.
1509  Builder.restoreIP(SavedIP);
1510 
1511  return TerminateHandler;
1512 }
1513 
1515  assert(EHPersonality::get(*this).usesFuncletPads() &&
1516  "use getTerminateLandingPad for non-funclet EH");
1517 
1518  llvm::BasicBlock *&TerminateFunclet = TerminateFunclets[CurrentFuncletPad];
1519  if (TerminateFunclet)
1520  return TerminateFunclet;
1521 
1522  CGBuilderTy::InsertPoint SavedIP = Builder.saveAndClearIP();
1523 
1524  // Set up the terminate handler. This block is inserted at the very
1525  // end of the function by FinishFunction.
1526  TerminateFunclet = createBasicBlock("terminate.handler");
1527  Builder.SetInsertPoint(TerminateFunclet);
1528 
1529  // Create the cleanuppad using the current parent pad as its token. Use 'none'
1530  // if this is a top-level terminate scope, which is the common case.
1531  SaveAndRestore<llvm::Instruction *> RestoreCurrentFuncletPad(
1532  CurrentFuncletPad);
1533  llvm::Value *ParentPad = CurrentFuncletPad;
1534  if (!ParentPad)
1535  ParentPad = llvm::ConstantTokenNone::get(CGM.getLLVMContext());
1536  CurrentFuncletPad = Builder.CreateCleanupPad(ParentPad);
1537 
1538  // Emit the __std_terminate call.
1539  llvm::Value *Exn = nullptr;
1540  // In case of wasm personality, we need to pass the exception value to
1541  // __clang_call_terminate function.
1542  if (getLangOpts().CPlusPlus &&
1544  llvm::Value *GetExnFn =
1545  CGM.getIntrinsic(llvm::Intrinsic::wasm_get_exception);
1546  Exn = Builder.CreateCall(GetExnFn, CurrentFuncletPad);
1547  }
1548  llvm::CallInst *terminateCall =
1549  CGM.getCXXABI().emitTerminateForUnexpectedException(*this, Exn);
1550  terminateCall->setDoesNotReturn();
1551  Builder.CreateUnreachable();
1552 
1553  // Restore the saved insertion state.
1554  Builder.restoreIP(SavedIP);
1555 
1556  return TerminateFunclet;
1557 }
1558 
1559 llvm::BasicBlock *CodeGenFunction::getEHResumeBlock(bool isCleanup) {
1560  if (EHResumeBlock) return EHResumeBlock;
1561 
1562  CGBuilderTy::InsertPoint SavedIP = Builder.saveIP();
1563 
1564  // We emit a jump to a notional label at the outermost unwind state.
1565  EHResumeBlock = createBasicBlock("eh.resume");
1566  Builder.SetInsertPoint(EHResumeBlock);
1567 
1568  const EHPersonality &Personality = EHPersonality::get(*this);
1569 
1570  // This can always be a call because we necessarily didn't find
1571  // anything on the EH stack which needs our help.
1572  const char *RethrowName = Personality.CatchallRethrowFn;
1573  if (RethrowName != nullptr && !isCleanup) {
1574  EmitRuntimeCall(getCatchallRethrowFn(CGM, RethrowName),
1575  getExceptionFromSlot())->setDoesNotReturn();
1576  Builder.CreateUnreachable();
1577  Builder.restoreIP(SavedIP);
1578  return EHResumeBlock;
1579  }
1580 
1581  // Recreate the landingpad's return value for the 'resume' instruction.
1582  llvm::Value *Exn = getExceptionFromSlot();
1583  llvm::Value *Sel = getSelectorFromSlot();
1584 
1585  llvm::Type *LPadType = llvm::StructType::get(Exn->getType(), Sel->getType());
1586  llvm::Value *LPadVal = llvm::UndefValue::get(LPadType);
1587  LPadVal = Builder.CreateInsertValue(LPadVal, Exn, 0, "lpad.val");
1588  LPadVal = Builder.CreateInsertValue(LPadVal, Sel, 1, "lpad.val");
1589 
1590  Builder.CreateResume(LPadVal);
1591  Builder.restoreIP(SavedIP);
1592  return EHResumeBlock;
1593 }
1594 
1596  EnterSEHTryStmt(S);
1597  {
1598  JumpDest TryExit = getJumpDestInCurrentScope("__try.__leave");
1599 
1600  SEHTryEpilogueStack.push_back(&TryExit);
1601  EmitStmt(S.getTryBlock());
1602  SEHTryEpilogueStack.pop_back();
1603 
1604  if (!TryExit.getBlock()->use_empty())
1605  EmitBlock(TryExit.getBlock(), /*IsFinished=*/true);
1606  else
1607  delete TryExit.getBlock();
1608  }
1609  ExitSEHTryStmt(S);
1610 }
1611 
1612 namespace {
1613 struct PerformSEHFinally final : EHScopeStack::Cleanup {
1614  llvm::Function *OutlinedFinally;
1615  PerformSEHFinally(llvm::Function *OutlinedFinally)
1616  : OutlinedFinally(OutlinedFinally) {}
1617 
1618  void Emit(CodeGenFunction &CGF, Flags F) override {
1619  ASTContext &Context = CGF.getContext();
1620  CodeGenModule &CGM = CGF.CGM;
1621 
1622  CallArgList Args;
1623 
1624  // Compute the two argument values.
1625  QualType ArgTys[2] = {Context.UnsignedCharTy, Context.VoidPtrTy};
1626  llvm::Value *LocalAddrFn = CGM.getIntrinsic(llvm::Intrinsic::localaddress);
1627  llvm::Value *FP = CGF.Builder.CreateCall(LocalAddrFn);
1628  llvm::Value *IsForEH =
1629  llvm::ConstantInt::get(CGF.ConvertType(ArgTys[0]), F.isForEHCleanup());
1630  Args.add(RValue::get(IsForEH), ArgTys[0]);
1631  Args.add(RValue::get(FP), ArgTys[1]);
1632 
1633  // Arrange a two-arg function info and type.
1634  const CGFunctionInfo &FnInfo =
1635  CGM.getTypes().arrangeBuiltinFunctionCall(Context.VoidTy, Args);
1636 
1637  auto Callee = CGCallee::forDirect(OutlinedFinally);
1638  CGF.EmitCall(FnInfo, Callee, ReturnValueSlot(), Args);
1639  }
1640 };
1641 } // end anonymous namespace
1642 
1643 namespace {
1644 /// Find all local variable captures in the statement.
1645 struct CaptureFinder : ConstStmtVisitor<CaptureFinder> {
1646  CodeGenFunction &ParentCGF;
1647  const VarDecl *ParentThis;
1649  Address SEHCodeSlot = Address::invalid();
1650  CaptureFinder(CodeGenFunction &ParentCGF, const VarDecl *ParentThis)
1651  : ParentCGF(ParentCGF), ParentThis(ParentThis) {}
1652 
1653  // Return true if we need to do any capturing work.
1654  bool foundCaptures() {
1655  return !Captures.empty() || SEHCodeSlot.isValid();
1656  }
1657 
1658  void Visit(const Stmt *S) {
1659  // See if this is a capture, then recurse.
1661  for (const Stmt *Child : S->children())
1662  if (Child)
1663  Visit(Child);
1664  }
1665 
1666  void VisitDeclRefExpr(const DeclRefExpr *E) {
1667  // If this is already a capture, just make sure we capture 'this'.
1669  Captures.insert(ParentThis);
1670  return;
1671  }
1672 
1673  const auto *D = dyn_cast<VarDecl>(E->getDecl());
1674  if (D && D->isLocalVarDeclOrParm() && D->hasLocalStorage())
1675  Captures.insert(D);
1676  }
1677 
1678  void VisitCXXThisExpr(const CXXThisExpr *E) {
1679  Captures.insert(ParentThis);
1680  }
1681 
1682  void VisitCallExpr(const CallExpr *E) {
1683  // We only need to add parent frame allocations for these builtins in x86.
1684  if (ParentCGF.getTarget().getTriple().getArch() != llvm::Triple::x86)
1685  return;
1686 
1687  unsigned ID = E->getBuiltinCallee();
1688  switch (ID) {
1689  case Builtin::BI__exception_code:
1690  case Builtin::BI_exception_code:
1691  // This is the simple case where we are the outermost finally. All we
1692  // have to do here is make sure we escape this and recover it in the
1693  // outlined handler.
1694  if (!SEHCodeSlot.isValid())
1695  SEHCodeSlot = ParentCGF.SEHCodeSlotStack.back();
1696  break;
1697  }
1698  }
1699 };
1700 } // end anonymous namespace
1701 
1703  Address ParentVar,
1704  llvm::Value *ParentFP) {
1705  llvm::CallInst *RecoverCall = nullptr;
1706  CGBuilderTy Builder(*this, AllocaInsertPt);
1707  if (auto *ParentAlloca = dyn_cast<llvm::AllocaInst>(ParentVar.getPointer())) {
1708  // Mark the variable escaped if nobody else referenced it and compute the
1709  // localescape index.
1710  auto InsertPair = ParentCGF.EscapedLocals.insert(
1711  std::make_pair(ParentAlloca, ParentCGF.EscapedLocals.size()));
1712  int FrameEscapeIdx = InsertPair.first->second;
1713  // call i8* @llvm.localrecover(i8* bitcast(@parentFn), i8* %fp, i32 N)
1714  llvm::Function *FrameRecoverFn = llvm::Intrinsic::getDeclaration(
1715  &CGM.getModule(), llvm::Intrinsic::localrecover);
1716  llvm::Constant *ParentI8Fn =
1717  llvm::ConstantExpr::getBitCast(ParentCGF.CurFn, Int8PtrTy);
1718  RecoverCall = Builder.CreateCall(
1719  FrameRecoverFn, {ParentI8Fn, ParentFP,
1720  llvm::ConstantInt::get(Int32Ty, FrameEscapeIdx)});
1721 
1722  } else {
1723  // If the parent didn't have an alloca, we're doing some nested outlining.
1724  // Just clone the existing localrecover call, but tweak the FP argument to
1725  // use our FP value. All other arguments are constants.
1726  auto *ParentRecover =
1727  cast<llvm::IntrinsicInst>(ParentVar.getPointer()->stripPointerCasts());
1728  assert(ParentRecover->getIntrinsicID() == llvm::Intrinsic::localrecover &&
1729  "expected alloca or localrecover in parent LocalDeclMap");
1730  RecoverCall = cast<llvm::CallInst>(ParentRecover->clone());
1731  RecoverCall->setArgOperand(1, ParentFP);
1732  RecoverCall->insertBefore(AllocaInsertPt);
1733  }
1734 
1735  // Bitcast the variable, rename it, and insert it in the local decl map.
1736  llvm::Value *ChildVar =
1737  Builder.CreateBitCast(RecoverCall, ParentVar.getType());
1738  ChildVar->setName(ParentVar.getName());
1739  return Address(ChildVar, ParentVar.getAlignment());
1740 }
1741 
1743  const Stmt *OutlinedStmt,
1744  bool IsFilter) {
1745  // Find all captures in the Stmt.
1746  CaptureFinder Finder(ParentCGF, ParentCGF.CXXABIThisDecl);
1747  Finder.Visit(OutlinedStmt);
1748 
1749  // We can exit early on x86_64 when there are no captures. We just have to
1750  // save the exception code in filters so that __exception_code() works.
1751  if (!Finder.foundCaptures() &&
1752  CGM.getTarget().getTriple().getArch() != llvm::Triple::x86) {
1753  if (IsFilter)
1754  EmitSEHExceptionCodeSave(ParentCGF, nullptr, nullptr);
1755  return;
1756  }
1757 
1758  llvm::Value *EntryFP = nullptr;
1759  CGBuilderTy Builder(CGM, AllocaInsertPt);
1760  if (IsFilter && CGM.getTarget().getTriple().getArch() == llvm::Triple::x86) {
1761  // 32-bit SEH filters need to be careful about FP recovery. The end of the
1762  // EH registration is passed in as the EBP physical register. We can
1763  // recover that with llvm.frameaddress(1).
1764  EntryFP = Builder.CreateCall(
1765  CGM.getIntrinsic(llvm::Intrinsic::frameaddress), {Builder.getInt32(1)});
1766  } else {
1767  // Otherwise, for x64 and 32-bit finally functions, the parent FP is the
1768  // second parameter.
1769  auto AI = CurFn->arg_begin();
1770  ++AI;
1771  EntryFP = &*AI;
1772  }
1773 
1774  llvm::Value *ParentFP = EntryFP;
1775  if (IsFilter) {
1776  // Given whatever FP the runtime provided us in EntryFP, recover the true
1777  // frame pointer of the parent function. We only need to do this in filters,
1778  // since finally funclets recover the parent FP for us.
1779  llvm::Function *RecoverFPIntrin =
1780  CGM.getIntrinsic(llvm::Intrinsic::x86_seh_recoverfp);
1781  llvm::Constant *ParentI8Fn =
1782  llvm::ConstantExpr::getBitCast(ParentCGF.CurFn, Int8PtrTy);
1783  ParentFP = Builder.CreateCall(RecoverFPIntrin, {ParentI8Fn, EntryFP});
1784  }
1785 
1786  // Create llvm.localrecover calls for all captures.
1787  for (const VarDecl *VD : Finder.Captures) {
1788  if (isa<ImplicitParamDecl>(VD)) {
1789  CGM.ErrorUnsupported(VD, "'this' captured by SEH");
1790  CXXThisValue = llvm::UndefValue::get(ConvertTypeForMem(VD->getType()));
1791  continue;
1792  }
1793  if (VD->getType()->isVariablyModifiedType()) {
1794  CGM.ErrorUnsupported(VD, "VLA captured by SEH");
1795  continue;
1796  }
1797  assert((isa<ImplicitParamDecl>(VD) || VD->isLocalVarDeclOrParm()) &&
1798  "captured non-local variable");
1799 
1800  // If this decl hasn't been declared yet, it will be declared in the
1801  // OutlinedStmt.
1802  auto I = ParentCGF.LocalDeclMap.find(VD);
1803  if (I == ParentCGF.LocalDeclMap.end())
1804  continue;
1805 
1806  Address ParentVar = I->second;
1807  setAddrOfLocalVar(
1808  VD, recoverAddrOfEscapedLocal(ParentCGF, ParentVar, ParentFP));
1809  }
1810 
1811  if (Finder.SEHCodeSlot.isValid()) {
1812  SEHCodeSlotStack.push_back(
1813  recoverAddrOfEscapedLocal(ParentCGF, Finder.SEHCodeSlot, ParentFP));
1814  }
1815 
1816  if (IsFilter)
1817  EmitSEHExceptionCodeSave(ParentCGF, ParentFP, EntryFP);
1818 }
1819 
1820 /// Arrange a function prototype that can be called by Windows exception
1821 /// handling personalities. On Win64, the prototype looks like:
1822 /// RetTy func(void *EHPtrs, void *ParentFP);
1824  bool IsFilter,
1825  const Stmt *OutlinedStmt) {
1826  SourceLocation StartLoc = OutlinedStmt->getBeginLoc();
1827 
1828  // Get the mangled function name.
1829  SmallString<128> Name;
1830  {
1831  llvm::raw_svector_ostream OS(Name);
1832  const NamedDecl *ParentSEHFn = ParentCGF.CurSEHParent;
1833  assert(ParentSEHFn && "No CurSEHParent!");
1834  MangleContext &Mangler = CGM.getCXXABI().getMangleContext();
1835  if (IsFilter)
1836  Mangler.mangleSEHFilterExpression(ParentSEHFn, OS);
1837  else
1838  Mangler.mangleSEHFinallyBlock(ParentSEHFn, OS);
1839  }
1840 
1841  FunctionArgList Args;
1842  if (CGM.getTarget().getTriple().getArch() != llvm::Triple::x86 || !IsFilter) {
1843  // All SEH finally functions take two parameters. Win64 filters take two
1844  // parameters. Win32 filters take no parameters.
1845  if (IsFilter) {
1846  Args.push_back(ImplicitParamDecl::Create(
1847  getContext(), /*DC=*/nullptr, StartLoc,
1848  &getContext().Idents.get("exception_pointers"),
1850  } else {
1851  Args.push_back(ImplicitParamDecl::Create(
1852  getContext(), /*DC=*/nullptr, StartLoc,
1853  &getContext().Idents.get("abnormal_termination"),
1855  }
1856  Args.push_back(ImplicitParamDecl::Create(
1857  getContext(), /*DC=*/nullptr, StartLoc,
1858  &getContext().Idents.get("frame_pointer"), getContext().VoidPtrTy,
1860  }
1861 
1862  QualType RetTy = IsFilter ? getContext().LongTy : getContext().VoidTy;
1863 
1864  const CGFunctionInfo &FnInfo =
1865  CGM.getTypes().arrangeBuiltinFunctionDeclaration(RetTy, Args);
1866 
1867  llvm::FunctionType *FnTy = CGM.getTypes().GetFunctionType(FnInfo);
1868  llvm::Function *Fn = llvm::Function::Create(
1869  FnTy, llvm::GlobalValue::InternalLinkage, Name.str(), &CGM.getModule());
1870 
1871  IsOutlinedSEHHelper = true;
1872 
1873  StartFunction(GlobalDecl(), RetTy, Fn, FnInfo, Args,
1874  OutlinedStmt->getBeginLoc(), OutlinedStmt->getBeginLoc());
1875  CurSEHParent = ParentCGF.CurSEHParent;
1876 
1877  CGM.SetLLVMFunctionAttributes(nullptr, FnInfo, CurFn);
1878  EmitCapturedLocals(ParentCGF, OutlinedStmt, IsFilter);
1879 }
1880 
1881 /// Create a stub filter function that will ultimately hold the code of the
1882 /// filter expression. The EH preparation passes in LLVM will outline the code
1883 /// from the main function body into this stub.
1884 llvm::Function *
1886  const SEHExceptStmt &Except) {
1887  const Expr *FilterExpr = Except.getFilterExpr();
1888  startOutlinedSEHHelper(ParentCGF, true, FilterExpr);
1889 
1890  // Emit the original filter expression, convert to i32, and return.
1891  llvm::Value *R = EmitScalarExpr(FilterExpr);
1892  R = Builder.CreateIntCast(R, ConvertType(getContext().LongTy),
1893  FilterExpr->getType()->isSignedIntegerType());
1894  Builder.CreateStore(R, ReturnValue);
1895 
1896  FinishFunction(FilterExpr->getEndLoc());
1897 
1898  return CurFn;
1899 }
1900 
1901 llvm::Function *
1903  const SEHFinallyStmt &Finally) {
1904  const Stmt *FinallyBlock = Finally.getBlock();
1905  startOutlinedSEHHelper(ParentCGF, false, FinallyBlock);
1906 
1907  // Emit the original filter expression, convert to i32, and return.
1908  EmitStmt(FinallyBlock);
1909 
1910  FinishFunction(FinallyBlock->getEndLoc());
1911 
1912  return CurFn;
1913 }
1914 
1916  llvm::Value *ParentFP,
1917  llvm::Value *EntryFP) {
1918  // Get the pointer to the EXCEPTION_POINTERS struct. This is returned by the
1919  // __exception_info intrinsic.
1920  if (CGM.getTarget().getTriple().getArch() != llvm::Triple::x86) {
1921  // On Win64, the info is passed as the first parameter to the filter.
1922  SEHInfo = &*CurFn->arg_begin();
1923  SEHCodeSlotStack.push_back(
1924  CreateMemTemp(getContext().IntTy, "__exception_code"));
1925  } else {
1926  // On Win32, the EBP on entry to the filter points to the end of an
1927  // exception registration object. It contains 6 32-bit fields, and the info
1928  // pointer is stored in the second field. So, GEP 20 bytes backwards and
1929  // load the pointer.
1930  SEHInfo = Builder.CreateConstInBoundsGEP1_32(Int8Ty, EntryFP, -20);
1931  SEHInfo = Builder.CreateBitCast(SEHInfo, Int8PtrTy->getPointerTo());
1932  SEHInfo = Builder.CreateAlignedLoad(Int8PtrTy, SEHInfo, getPointerAlign());
1933  SEHCodeSlotStack.push_back(recoverAddrOfEscapedLocal(
1934  ParentCGF, ParentCGF.SEHCodeSlotStack.back(), ParentFP));
1935  }
1936 
1937  // Save the exception code in the exception slot to unify exception access in
1938  // the filter function and the landing pad.
1939  // struct EXCEPTION_POINTERS {
1940  // EXCEPTION_RECORD *ExceptionRecord;
1941  // CONTEXT *ContextRecord;
1942  // };
1943  // int exceptioncode = exception_pointers->ExceptionRecord->ExceptionCode;
1944  llvm::Type *RecordTy = CGM.Int32Ty->getPointerTo();
1945  llvm::Type *PtrsTy = llvm::StructType::get(RecordTy, CGM.VoidPtrTy);
1946  llvm::Value *Ptrs = Builder.CreateBitCast(SEHInfo, PtrsTy->getPointerTo());
1947  llvm::Value *Rec = Builder.CreateStructGEP(PtrsTy, Ptrs, 0);
1948  Rec = Builder.CreateAlignedLoad(Rec, getPointerAlign());
1949  llvm::Value *Code = Builder.CreateAlignedLoad(Rec, getIntAlign());
1950  assert(!SEHCodeSlotStack.empty() && "emitting EH code outside of __except");
1951  Builder.CreateStore(Code, SEHCodeSlotStack.back());
1952 }
1953 
1955  // Sema should diagnose calling this builtin outside of a filter context, but
1956  // don't crash if we screw up.
1957  if (!SEHInfo)
1958  return llvm::UndefValue::get(Int8PtrTy);
1959  assert(SEHInfo->getType() == Int8PtrTy);
1960  return SEHInfo;
1961 }
1962 
1964  assert(!SEHCodeSlotStack.empty() && "emitting EH code outside of __except");
1965  return Builder.CreateLoad(SEHCodeSlotStack.back());
1966 }
1967 
1969  // Abnormal termination is just the first parameter to the outlined finally
1970  // helper.
1971  auto AI = CurFn->arg_begin();
1972  return Builder.CreateZExt(&*AI, Int32Ty);
1973 }
1974 
1976  llvm::Function *FinallyFunc) {
1977  EHStack.pushCleanup<PerformSEHFinally>(Kind, FinallyFunc);
1978 }
1979 
1981  CodeGenFunction HelperCGF(CGM, /*suppressNewContext=*/true);
1982  if (const SEHFinallyStmt *Finally = S.getFinallyHandler()) {
1983  // Outline the finally block.
1984  llvm::Function *FinallyFunc =
1985  HelperCGF.GenerateSEHFinallyFunction(*this, *Finally);
1986 
1987  // Push a cleanup for __finally blocks.
1988  EHStack.pushCleanup<PerformSEHFinally>(NormalAndEHCleanup, FinallyFunc);
1989  return;
1990  }
1991 
1992  // Otherwise, we must have an __except block.
1993  const SEHExceptStmt *Except = S.getExceptHandler();
1994  assert(Except);
1995  EHCatchScope *CatchScope = EHStack.pushCatch(1);
1996  SEHCodeSlotStack.push_back(
1997  CreateMemTemp(getContext().IntTy, "__exception_code"));
1998 
1999  // If the filter is known to evaluate to 1, then we can use the clause
2000  // "catch i8* null". We can't do this on x86 because the filter has to save
2001  // the exception code.
2002  llvm::Constant *C =
2004  getContext().IntTy);
2005  if (CGM.getTarget().getTriple().getArch() != llvm::Triple::x86 && C &&
2006  C->isOneValue()) {
2007  CatchScope->setCatchAllHandler(0, createBasicBlock("__except"));
2008  return;
2009  }
2010 
2011  // In general, we have to emit an outlined filter function. Use the function
2012  // in place of the RTTI typeinfo global that C++ EH uses.
2013  llvm::Function *FilterFunc =
2014  HelperCGF.GenerateSEHFilterFunction(*this, *Except);
2015  llvm::Constant *OpaqueFunc =
2016  llvm::ConstantExpr::getBitCast(FilterFunc, Int8PtrTy);
2017  CatchScope->setHandler(0, OpaqueFunc, createBasicBlock("__except.ret"));
2018 }
2019 
2021  // Just pop the cleanup if it's a __finally block.
2022  if (S.getFinallyHandler()) {
2023  PopCleanupBlock();
2024  return;
2025  }
2026 
2027  // Otherwise, we must have an __except block.
2028  const SEHExceptStmt *Except = S.getExceptHandler();
2029  assert(Except && "__try must have __finally xor __except");
2030  EHCatchScope &CatchScope = cast<EHCatchScope>(*EHStack.begin());
2031 
2032  // Don't emit the __except block if the __try block lacked invokes.
2033  // TODO: Model unwind edges from instructions, either with iload / istore or
2034  // a try body function.
2035  if (!CatchScope.hasEHBranches()) {
2036  CatchScope.clearHandlerBlocks();
2037  EHStack.popCatch();
2038  SEHCodeSlotStack.pop_back();
2039  return;
2040  }
2041 
2042  // The fall-through block.
2043  llvm::BasicBlock *ContBB = createBasicBlock("__try.cont");
2044 
2045  // We just emitted the body of the __try; jump to the continue block.
2046  if (HaveInsertPoint())
2047  Builder.CreateBr(ContBB);
2048 
2049  // Check if our filter function returned true.
2050  emitCatchDispatchBlock(*this, CatchScope);
2051 
2052  // Grab the block before we pop the handler.
2053  llvm::BasicBlock *CatchPadBB = CatchScope.getHandler(0).Block;
2054  EHStack.popCatch();
2055 
2056  EmitBlockAfterUses(CatchPadBB);
2057 
2058  // __except blocks don't get outlined into funclets, so immediately do a
2059  // catchret.
2060  llvm::CatchPadInst *CPI =
2061  cast<llvm::CatchPadInst>(CatchPadBB->getFirstNonPHI());
2062  llvm::BasicBlock *ExceptBB = createBasicBlock("__except");
2063  Builder.CreateCatchRet(CPI, ExceptBB);
2064  EmitBlock(ExceptBB);
2065 
2066  // On Win64, the exception code is returned in EAX. Copy it into the slot.
2067  if (CGM.getTarget().getTriple().getArch() != llvm::Triple::x86) {
2068  llvm::Function *SEHCodeIntrin =
2069  CGM.getIntrinsic(llvm::Intrinsic::eh_exceptioncode);
2070  llvm::Value *Code = Builder.CreateCall(SEHCodeIntrin, {CPI});
2071  Builder.CreateStore(Code, SEHCodeSlotStack.back());
2072  }
2073 
2074  // Emit the __except body.
2075  EmitStmt(Except->getBlock());
2076 
2077  // End the lifetime of the exception code.
2078  SEHCodeSlotStack.pop_back();
2079 
2080  if (HaveInsertPoint())
2081  Builder.CreateBr(ContBB);
2082 
2083  EmitBlock(ContBB);
2084 }
2085 
2087  // If this code is reachable then emit a stop point (if generating
2088  // debug info). We have to do this ourselves because we are on the
2089  // "simple" statement path.
2090  if (HaveInsertPoint())
2091  EmitStopPoint(&S);
2092 
2093  // This must be a __leave from a __finally block, which we warn on and is UB.
2094  // Just emit unreachable.
2095  if (!isSEHTryScope()) {
2096  Builder.CreateUnreachable();
2097  Builder.ClearInsertionPoint();
2098  return;
2099  }
2100 
2101  EmitBranchThroughCleanup(*SEHTryEpilogueStack.back());
2102 }
virtual void mangleSEHFilterExpression(const NamedDecl *EnclosingDecl, raw_ostream &Out)=0
ReturnValueSlot - Contains the address where the return value of a function can be stored...
Definition: CGCall.h:361
Represents a function declaration or definition.
Definition: Decl.h:1722
llvm::IntegerType * IntTy
int
EHScopeStack::stable_iterator getEnclosingEHScope() const
Definition: CGCleanup.h:138
Other implicit parameter.
Definition: Decl.h:1501
CompoundStmt * getBlock() const
Definition: Stmt.h:2174
Smart pointer class that efficiently represents Objective-C method names.
void setCatchAllHandler(unsigned I, llvm::BasicBlock *Block)
Definition: CGCleanup.h:193
CanQualType VoidPtrTy
Definition: ASTContext.h:1051
A (possibly-)qualified type.
Definition: Type.h:640
void EmitSEHLeaveStmt(const SEHLeaveStmt &S)
bool usesFuncletPads() const
Does this personality use landingpads or the family of pad instructions designed to form funclets...
Definition: CGCleanup.h:634
unsigned getNumExceptions() const
Definition: Type.h:3733
const Expr * getSubExpr() const
Definition: ExprCXX.h:1116
ConstStmtVisitor - This class implements a simple visitor for Stmt subclasses.
Definition: StmtVisitor.h:195
llvm::BasicBlock * getCachedEHDispatchBlock() const
Definition: CGCleanup.h:124
bool HaveInsertPoint() const
HaveInsertPoint - True if an insertion point is defined.
static const EHPersonality GNU_C_SJLJ
Definition: CGCleanup.h:616
void EmitCXXTryStmt(const CXXTryStmt &S)
Stmt - This represents one statement.
Definition: Stmt.h:66
CXXCatchStmt * getHandler(unsigned i)
Definition: StmtCXX.h:120
static const EHPersonality MSVC_C_specific_handler
Definition: CGCleanup.h:628
const llvm::Triple & getTriple() const
Returns the target triple of the primary target.
Definition: TargetInfo.h:949
static const EHPersonality MSVC_CxxFrameHandler3
Definition: CGCleanup.h:629
tooling::Replacements cleanup(const FormatStyle &Style, StringRef Code, ArrayRef< tooling::Range > Ranges, StringRef FileName="<stdin>")
Clean up any erroneous/redundant code in the given Ranges in Code.
Definition: Format.cpp:2050
bool hasEHBranches() const
Definition: CGCleanup.h:132
Decl - This represents one declaration (or definition), e.g.
Definition: DeclBase.h:86
Stmt * getHandlerBlock() const
Definition: StmtCXX.h:60
const Decl * CurCodeDecl
CurCodeDecl - This is the inner-most code context, which includes blocks.
static const EHPersonality GNU_C
Definition: CGCleanup.h:615
virtual void mangleSEHFinallyBlock(const NamedDecl *EnclosingDecl, raw_ostream &Out)=0
QualType getNonReferenceType() const
If Type is a reference type (e.g., const int&), returns the type that the reference refers to ("const...
Definition: Type.h:6066
Represents Objective-C&#39;s @throw statement.
Definition: StmtObjC.h:353
CanQualType LongTy
Definition: ASTContext.h:1032
static llvm::Constant * getUnexpectedFn(CodeGenModule &CGM)
Definition: CGException.cpp:42
void EmitSEHExceptionCodeSave(CodeGenFunction &ParentCGF, llvm::Value *ParentFP, llvm::Value *EntryEBP)
bool usesSEHTry() const
Indicates the function uses __try.
Definition: Decl.h:2098
static const EHPersonality & getObjCXXPersonality(const TargetInfo &Target, const LangOptions &L)
Determines the personality function to use when both C++ and Objective-C exceptions are being caught...
static llvm::Constant * getPersonalityFn(CodeGenModule &CGM, const EHPersonality &Personality)
unsigned getNumFilters() const
Definition: CGCleanup.h:461
llvm::IntegerType * Int8Ty
i8, i16, i32, and i64
&#39;gcc&#39; is the Objective-C runtime shipped with GCC, implementing a fragile Objective-C ABI ...
Definition: ObjCRuntime.h:53
RValue EmitCall(const CGFunctionInfo &CallInfo, const CGCallee &Callee, ReturnValueSlot ReturnValue, const CallArgList &Args, llvm::Instruction **callOrInvoke, SourceLocation Loc)
EmitCall - Generate a call of the given function, expecting the given result type, and using the given argument list which specifies both the LLVM arguments and the types they were derived from.
Definition: CGCall.cpp:3782
Represents a variable declaration or definition.
Definition: Decl.h:820
const T * getAs() const
Member-template getAs<specific type>&#39;.
Definition: Type.h:6530
unsigned getNumHandlers() const
Definition: CGCleanup.h:189
llvm::Value * getPointer() const
Definition: Address.h:38
iterator begin() const
Returns an iterator pointing to the innermost EH scope.
Definition: CGCleanup.h:567
llvm::BasicBlock * EmitLandingPad()
Emits a landing pad for the current EH stack.
A protected scope for zero-cost EH handling.
Definition: CGCleanup.h:44
Defines the Objective-C statement AST node classes.
A C++ throw-expression (C++ [except.throw]).
Definition: ExprCXX.h:1094
static const EHPersonality & getObjCPersonality(const TargetInfo &Target, const LangOptions &L)
A scope which attempts to handle some, possibly all, types of exceptions.
Definition: CGCleanup.h:148
The collection of all-type qualifiers we support.
Definition: Type.h:139
void add(RValue rvalue, QualType type)
Definition: CGCall.h:285
A jump destination is an abstract label, branching to which may require a jump out through normal cle...
bool isNoexceptExceptionSpec(ExceptionSpecificationType ESpecType)
void popCatchScope()
popCatchScope - Pops the catch scope at the top of the EHScope stack, emitting any required code (oth...
const TargetInfo & getTarget() const
llvm::BasicBlock * getTerminateHandler()
getTerminateHandler - Return a handler (not a landing pad, just a catch handler) that just calls term...
&#39;macosx-fragile&#39; is the Apple-provided NeXT-derived runtime on Mac OS X platforms that use the fragil...
Definition: ObjCRuntime.h:40
const char * CatchallRethrowFn
Definition: CGCleanup.h:610
CodeGenFunction - This class organizes the per-function state that is used while generating LLVM code...
Holds long-lived AST nodes (such as types and decls) that can be referred to throughout the semantic ...
Definition: ASTContext.h:153
QualType getCaughtType() const
Definition: StmtCXX.cpp:20
SmallVector< Address, 1 > SEHCodeSlotStack
A stack of exception code slots.
SourceLocation getBeginLoc() const LLVM_READONLY
Definition: Stmt.cpp:280
static const EHPersonality GNU_CPlusPlus_SJLJ
Definition: CGCleanup.h:625
llvm::CallInst * EmitRuntimeCall(llvm::Value *callee, const Twine &name="")
Denotes a cleanup that should run when a scope is exited using exceptional control flow (a throw stat...
Definition: EHScopeStack.h:81
static const EHPersonality & get(CodeGenModule &CGM, const FunctionDecl *FD)
Keeps track of the various options that can be enabled, which controls the dialect of C or C++ that i...
Definition: LangOptions.h:50
Address getExceptionSlot()
Returns a pointer to the function&#39;s exception object and selector slot, which is assigned in every la...
void setFilter(unsigned i, llvm::Value *filterValue)
Definition: CGCleanup.h:463
class EHCatchScope * pushCatch(unsigned NumHandlers)
Push a set of catch handlers on the stack.
Definition: CGCleanup.cpp:251
bool isNeXTFamily() const
Is this runtime basically of the NeXT family of runtimes?
Definition: ObjCRuntime.h:135
static llvm::Constant * getFreeExceptionFn(CodeGenModule &CGM)
Definition: CGException.cpp:33
static llvm::Constant * getCatchAllValue(CodeGenFunction &CGF)
Returns the value to inject into a selector to indicate the presence of a catch-all.
void ExitSEHTryStmt(const SEHTryStmt &S)
QualType getExceptionType(unsigned i) const
Definition: Type.h:3734
iterator begin() const
Definition: CGCleanup.h:224
CharUnits getAlignment() const
Return the alignment of this pointer.
Definition: Address.h:67
child_range children()
Definition: Stmt.cpp:229
const Handler & getHandler(unsigned I) const
Definition: CGCleanup.h:209
static const EHPersonality GNUstep_ObjC
Definition: CGCleanup.h:621
llvm::Constant * getTerminateFn()
Get the declaration of std::terminate for the platform.
Definition: CGException.cpp:51
llvm::BasicBlock * getInvokeDestImpl()
llvm::Function * GenerateSEHFinallyFunction(CodeGenFunction &ParentCGF, const SEHFinallyStmt &Finally)
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 ForceCleanup(std::initializer_list< llvm::Value **> ValuesToReload={})
Force the emission of cleanups now, instead of waiting until this object is destroyed.
Represents the body of a CapturedStmt, and serves as its DeclContext.
Definition: Decl.h:4015
llvm::AllocaInst * CreateTempAlloca(llvm::Type *Ty, const Twine &Name="tmp", llvm::Value *ArraySize=nullptr)
CreateTempAlloca - This creates an alloca and inserts it into the entry block if ArraySize is nullptr...
Definition: CGExpr.cpp:106
CanQualType UnsignedCharTy
Definition: ASTContext.h:1033
Represents the this expression in C++.
Definition: ExprCXX.h:1046
llvm::Constant * CreateRuntimeFunction(llvm::FunctionType *Ty, StringRef Name, llvm::AttributeList ExtraAttrs=llvm::AttributeList(), bool Local=false)
Create a new runtime function with the specified type and name.
static ImplicitParamDecl * Create(ASTContext &C, DeclContext *DC, SourceLocation IdLoc, IdentifierInfo *Id, QualType T, ImplicitParamKind ParamKind)
Create implicit parameter.
Definition: Decl.cpp:4366
&#39;watchos&#39; is a variant of iOS for Apple&#39;s watchOS.
Definition: ObjCRuntime.h:49
bool isValid() const
Definition: Address.h:36
static const EHPersonality & getCPersonality(const TargetInfo &Target, const LangOptions &L)
Represents a prototype with parameter type info, e.g.
Definition: Type.h:3436
llvm::CallInst * EmitNounwindRuntimeCall(llvm::Value *callee, const Twine &name="")
static const EHPersonality MSVC_except_handler
Definition: CGCleanup.h:627
static llvm::Constant * getOpaquePersonalityFn(CodeGenModule &CGM, const EHPersonality &Personality)
Exposes information about the current target.
Definition: TargetInfo.h:54
CatchTypeInfo Type
A type info value, or null (C++ null, not an LLVM null pointer) for a catch-all.
Definition: CGCleanup.h:158
void EmitCapturedLocals(CodeGenFunction &ParentCGF, const Stmt *OutlinedStmt, bool IsFilter)
Scan the outlined statement for captures from the parent function.
Expr - This represents one expression.
Definition: Expr.h:106
void enter(CodeGenFunction &CGF, const Stmt *Finally, llvm::Constant *beginCatchFn, llvm::Constant *endCatchFn, llvm::Constant *rethrowFn)
Enters a finally block for an implementation using zero-cost exceptions.
static bool PersonalityHasOnlyCXXUses(llvm::Constant *Fn)
Check whether a personality function could reasonably be swapped for a C++ personality function...
&#39;macosx&#39; is the Apple-provided NeXT-derived runtime on Mac OS X platforms that use the non-fragile AB...
Definition: ObjCRuntime.h:35
static Address invalid()
Definition: Address.h:35
Enters a new scope for capturing cleanups, all of which will be executed once the scope is exited...
llvm::Function * GenerateSEHFilterFunction(CodeGenFunction &ParentCGF, const SEHExceptStmt &Except)
Create a stub filter function that will ultimately hold the code of the filter expression.
static CGCallee forDirect(llvm::Constant *functionPtr, const CGCalleeInfo &abstractInfo=CGCalleeInfo())
Definition: CGCall.h:134
VarDecl * getExceptionDecl() const
Definition: StmtCXX.h:58
llvm::PointerType * getType() const
Return the type of the pointer value.
Definition: Address.h:44
void EmitSEHTryStmt(const SEHTryStmt &S)
void pushSEHCleanup(CleanupKind kind, llvm::Function *FinallyFunc)
llvm::BasicBlock * Block
The catch handler for this type.
Definition: CGCleanup.h:161
static CharUnits fromQuantity(QuantityType Quantity)
fromQuantity - Construct a CharUnits quantity from a raw integer type.
Definition: CharUnits.h:63
CXXTryStmt - A C++ try block, including all handlers.
Definition: StmtCXX.h:73
bool refersToEnclosingVariableOrCapture() const
Does this DeclRefExpr refer to an enclosing local or a captured variable?
Definition: Expr.h:1197
llvm::Value * getExceptionFromSlot()
Returns the contents of the function&#39;s exception object and selector slots.
static void emitCatchDispatchBlock(CodeGenFunction &CGF, EHCatchScope &catchScope)
Emit the structure of the dispatch block for the given catch scope.
llvm::LLVMContext & getLLVMContext()
const CGFunctionInfo & arrangeBuiltinFunctionCall(QualType resultType, const CallArgList &args)
Definition: CGCall.cpp:640
bool isSignedIntegerType() const
Return true if this is an integer type that is signed, according to C99 6.2.5p4 [char, signed char, short, int, long..], or an enum decl which has a signed representation.
Definition: Type.cpp:1848
QualType getType() const
Definition: Expr.h:128
static const EHPersonality GNU_ObjCXX
Definition: CGCleanup.h:622
bool hasTerminate() const
Does this runtime provide an objc_terminate function?
Definition: ObjCRuntime.h:258
clang::ObjCRuntime ObjCRuntime
Definition: LangOptions.h:173
static const EHPersonality GNU_ObjC_SEH
Definition: CGCleanup.h:620
const TargetInfo & getTarget() const
ValueDecl * getDecl()
Definition: Expr.h:1065
&#39;gnustep&#39; is the modern non-fragile GNUstep runtime.
Definition: ObjCRuntime.h:56
const LangOptions & getLangOpts() const
ASTContext & getContext() const
llvm::StoreInst * CreateFlagStore(bool Value, llvm::Value *Addr)
Emit a store to an i1 flag variable.
Definition: CGBuilder.h:136
GlobalDecl - represents a global declaration.
Definition: GlobalDecl.h:35
SourceLocation getEndLoc() const LLVM_READONLY
Definition: Stmt.cpp:293
unsigned getBuiltinCallee() const
getBuiltinCallee - If this is a call to a builtin, return the builtin ID of the callee.
Definition: Expr.cpp:1314
llvm::BasicBlock * getEHDispatchBlock(EHScopeStack::stable_iterator scope)
The l-value was considered opaque, so the alignment was determined from a type.
static void emitFilterDispatchBlock(CodeGenFunction &CGF, EHFilterScope &filterScope)
Emit the dispatch block for a filter scope if necessary.
Address recoverAddrOfEscapedLocal(CodeGenFunction &ParentCGF, Address ParentVar, llvm::Value *ParentFP)
Recovers the address of a local in a parent function.
Enumerates target-specific builtins in their own namespaces within namespace clang.
Address CreateBitCast(Address Addr, llvm::Type *Ty, const llvm::Twine &Name="")
Definition: CGBuilder.h:142
Kind
Encodes a location in the source.
void EnsureInsertPoint()
EnsureInsertPoint - Ensure that an insertion point is defined so that emitted IR has a place to go...
A saved depth on the scope stack.
Definition: EHScopeStack.h:107
unsigned getNumHandlers() const
Definition: StmtCXX.h:119
bool isVariablyModifiedType() const
Whether this type is a variably-modified type (C99 6.7.5).
Definition: Type.h:1962
&#39;objfw&#39; is the Objective-C runtime included in ObjFW
Definition: ObjCRuntime.h:59
llvm::BasicBlock * getUnreachableBlock()
llvm::CallSite EmitRuntimeCallOrInvoke(llvm::Value *callee, ArrayRef< llvm::Value *> args, const Twine &name="")
Emits a call or invoke instruction to the given runtime function.
Definition: CGCall.cpp:3741
Kind getKind() const
Definition: ObjCRuntime.h:77
static const EHPersonality & getCXXPersonality(const TargetInfo &Target, const LangOptions &L)
MangleContext - Context for tracking state which persists across multiple calls to the C++ name mangl...
Definition: Mangle.h:43
void EmitStmt(const Stmt *S, ArrayRef< const Attr *> Attrs=None)
EmitStmt - Emit the code for the statement.
Definition: CGStmt.cpp:48
CanQualType VoidTy
Definition: ASTContext.h:1023
bool isObjCObjectPointerType() const
Definition: Type.h:6214
An aligned address.
Definition: Address.h:25
bool isWasmPersonality() const
Definition: CGCleanup.h:643
llvm::BasicBlock * getEHResumeBlock(bool isCleanup)
void setCachedEHDispatchBlock(llvm::BasicBlock *block)
Definition: CGCleanup.h:128
llvm::Instruction * CurrentFuncletPad
llvm::Value * getFilter(unsigned i) const
Definition: CGCleanup.h:468
JumpDest getJumpDestInCurrentScope(llvm::BasicBlock *Target)
The given basic block lies in the current EH scope, but may be a target of a potentially scope-crossi...
const VersionTuple & getVersion() const
Definition: ObjCRuntime.h:78
void EmitStartEHSpec(const Decl *D)
EmitStartEHSpec - Emit the start of the exception spec.
The MS C++ ABI needs a pointer to RTTI data plus some flags to describe the type of a catch handler...
Definition: CGCleanup.h:38
ExceptionSpecificationType getExceptionSpecType() const
Get the kind of exception specification on this function.
Definition: Type.h:3707
SourceLocation getExprLoc() const LLVM_READONLY
getExprLoc - Return the preferred location for the arrow when diagnosing a problem with a generic exp...
Definition: Expr.cpp:216
static const EHPersonality NeXT_ObjC
Definition: CGCleanup.h:623
llvm::BasicBlock * getFuncletEHDispatchBlock(EHScopeStack::stable_iterator scope)
FunctionArgList - Type for representing both the decl and type of parameters to a function...
Definition: CGCall.h:356
CGFunctionInfo - Class to encapsulate the information about a function definition.
Kind getKind() const
Definition: CGCleanup.h:114
This class organizes the cross-function state that is used while generating LLVM code.
Dataflow Directional Tag Classes.
static ApplyDebugLocation CreateDefaultArtificial(CodeGenFunction &CGF, SourceLocation TemporaryLocation)
Apply TemporaryLocation if it is valid.
Definition: CGDebugInfo.h:696
static bool LandingPadHasOnlyCXXUses(llvm::LandingPadInst *LPI)
Check whether a landingpad instruction only uses C++ features.
static const EHPersonality GNU_CPlusPlus_SEH
Definition: CGCleanup.h:626
The basic abstraction for the target Objective-C runtime.
Definition: ObjCRuntime.h:28
static const EHPersonality GNU_ObjC
Definition: CGCleanup.h:618
static bool isNonEHScope(const EHScope &S)
Check whether this is a non-EH scope, i.e.
void EmitAnyExprToExn(const Expr *E, Address Addr)
llvm::LoadInst * CreateAlignedLoad(llvm::Value *Addr, CharUnits Align, const llvm::Twine &Name="")
Definition: CGBuilder.h:91
llvm::LoadInst * CreateLoad(Address Addr, const llvm::Twine &Name="")
Definition: CGBuilder.h:70
SEHExceptStmt * getExceptHandler() const
Returns 0 if not defined.
Definition: Stmt.cpp:950
llvm::Function * getIntrinsic(unsigned IID, ArrayRef< llvm::Type *> Tys=None)
llvm::StoreInst * CreateStore(llvm::Value *Val, Address Addr, bool IsVolatile=false)
Definition: CGBuilder.h:108
llvm::Module & getModule() const
virtual bool hasFeature(StringRef Feature) const
Determine whether the given target has the given feature.
Definition: TargetInfo.h:1081
Represents a __leave statement.
Definition: Stmt.h:2242
&#39;ios&#39; is the Apple-provided NeXT-derived runtime on iOS or the iOS simulator; it is always non-fragil...
Definition: ObjCRuntime.h:45
llvm::BasicBlock * getTerminateFunclet()
getTerminateLandingPad - Return a cleanup funclet that just calls terminate.
CanThrowResult canThrow() const
Determine whether this function type has a non-throwing exception specification.
Definition: Type.cpp:2964
static const EHPersonality GNU_CPlusPlus
Definition: CGCleanup.h:624
llvm::LoadInst * CreateFlagLoad(llvm::Value *Addr, const llvm::Twine &Name="")
Emit a load from an i1 flag variable.
Definition: CGBuilder.h:129
llvm::StringRef getName() const
Return the IR name of the pointer value.
Definition: Address.h:62
static const EHPersonality GNU_ObjC_SJLJ
Definition: CGCleanup.h:619
Internal linkage, which indicates that the entity can be referred to from within the translation unit...
Definition: Linkage.h:32
ExceptionSpecificationType
The various types of exception specifications that exist in C++11.
void EmitBlock(llvm::BasicBlock *BB, bool IsFinished=false)
EmitBlock - Emit the given block.
Definition: CGStmt.cpp:445
void EnterCXXTryStmt(const CXXTryStmt &S, bool IsFnTryBlock=false)
SEHFinallyStmt * getFinallyHandler() const
Definition: Stmt.cpp:954
static const EHPersonality & getSEHPersonalityMSVC(const llvm::Triple &T)
QualType getUnqualifiedType() const
Retrieve the unqualified variant of the given type, removing as little sugar as possible.
Definition: Type.h:5973
Expr * getFilterExpr() const
Definition: Stmt.h:2129
llvm::BasicBlock * getTerminateLandingPad()
getTerminateLandingPad - Return a landing pad that just calls terminate.
CXXCatchStmt - This represents a C++ catch block.
Definition: StmtCXX.h:29
llvm::Type * ConvertType(QualType T)
Qualifiers getQualifiers() const
Retrieve the set of qualifiers applied to this type.
Definition: Type.h:5920
static const EHPersonality GNU_C_SEH
Definition: CGCleanup.h:617
The exceptions personality for a function.
Definition: CGCleanup.h:604
llvm::Constant * RTTI
Definition: CGCleanup.h:39
CompoundStmt * getTryBlock()
Definition: StmtCXX.h:112
llvm::Value * EmitSEHAbnormalTermination()
CallExpr - Represents a function call (C99 6.5.2.2, C++ [expr.call]).
Definition: Expr.h:2406
llvm::Constant * tryEmitAbstract(const Expr *E, QualType T)
Try to emit the result of the given expression as an abstract constant.
void EnterSEHTryStmt(const SEHTryStmt &S)
void startOutlinedSEHHelper(CodeGenFunction &ParentCGF, bool IsFilter, const Stmt *OutlinedStmt)
Arrange a function prototype that can be called by Windows exception handling personalities.
CGCXXABI & getCXXABI() const
CanQualType IntTy
Definition: ASTContext.h:1032
An exceptions scope which filters exceptions thrown through it.
Definition: CGCleanup.h:438
A reference to a declared variable, function, enum, etc.
Definition: Expr.h:980
static RValue get(llvm::Value *V)
Definition: CGValue.h:86
void ExitCXXTryStmt(const CXXTryStmt &S, bool IsFnTryBlock=false)
void EmitBranchThroughCleanup(JumpDest Dest)
EmitBranchThroughCleanup - Emit a branch from the current insert block through the normal cleanup han...
Definition: CGCleanup.cpp:1050
void EmitEndEHSpec(const Decl *D)
EmitEndEHSpec - Emit the end of the exception spec.
static llvm::Constant * getCatchallRethrowFn(CodeGenModule &CGM, StringRef Name)
Definition: CGException.cpp:77
llvm::StoreInst * CreateAlignedStore(llvm::Value *Val, llvm::Value *Addr, CharUnits Align, bool IsVolatile=false)
Definition: CGBuilder.h:115
static const EHPersonality GNU_Wasm_CPlusPlus
Definition: CGCleanup.h:630
QualType getType() const
Definition: Decl.h:651
Information for lazily generating a cleanup.
Definition: EHScopeStack.h:147
This represents a decl that may have a name.
Definition: Decl.h:248
A non-stable pointer into the scope stack.
Definition: CGCleanup.h:503
void EmitBlockAfterUses(llvm::BasicBlock *BB)
EmitBlockAfterUses - Emit the given block somewhere hopefully near its uses, and leave the insertion ...
Definition: CGStmt.cpp:482
static void emitCatchPadBlock(CodeGenFunction &CGF, EHCatchScope &CatchScope)
CallArgList - Type for representing both the value and type of arguments in a call.
Definition: CGCall.h:260
void PopCleanupBlock(bool FallThroughIsBranchThrough=false)
PopCleanupBlock - Will pop the cleanup entry on the stack and process all branch fixups.
Definition: CGCleanup.cpp:651
void setHandler(unsigned I, llvm::Constant *Type, llvm::BasicBlock *Block)
Definition: CGCleanup.h:197
CompoundStmt * getTryBlock() const
Definition: Stmt.h:2222
CompoundStmt * getBlock() const
Definition: Stmt.h:2133
void EmitCXXThrowExpr(const CXXThrowExpr *E, bool KeepInsertionPoint=true)
bool isLocalVarDeclOrParm() const
Similar to isLocalVarDecl but also includes parameters.
Definition: Decl.h:1119
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.
static void emitWasmCatchPadBlock(CodeGenFunction &CGF, EHCatchScope &CatchScope)