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().ObjC &&
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.ObjC)
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  llvm::PointerType* Int8PtrTy = llvm::PointerType::get(
254  llvm::Type::getInt8Ty(CGM.getLLVMContext()),
255  CGM.getDataLayout().getProgramAddressSpace());
256 
257  return llvm::ConstantExpr::getBitCast(Fn, Int8PtrTy);
258 }
259 
260 /// Check whether a landingpad instruction only uses C++ features.
261 static bool LandingPadHasOnlyCXXUses(llvm::LandingPadInst *LPI) {
262  for (unsigned I = 0, E = LPI->getNumClauses(); I != E; ++I) {
263  // Look for something that would've been returned by the ObjC
264  // runtime's GetEHType() method.
265  llvm::Value *Val = LPI->getClause(I)->stripPointerCasts();
266  if (LPI->isCatch(I)) {
267  // Check if the catch value has the ObjC prefix.
268  if (llvm::GlobalVariable *GV = dyn_cast<llvm::GlobalVariable>(Val))
269  // ObjC EH selector entries are always global variables with
270  // names starting like this.
271  if (GV->getName().startswith("OBJC_EHTYPE"))
272  return false;
273  } else {
274  // Check if any of the filter values have the ObjC prefix.
275  llvm::Constant *CVal = cast<llvm::Constant>(Val);
276  for (llvm::User::op_iterator
277  II = CVal->op_begin(), IE = CVal->op_end(); II != IE; ++II) {
278  if (llvm::GlobalVariable *GV =
279  cast<llvm::GlobalVariable>((*II)->stripPointerCasts()))
280  // ObjC EH selector entries are always global variables with
281  // names starting like this.
282  if (GV->getName().startswith("OBJC_EHTYPE"))
283  return false;
284  }
285  }
286  }
287  return true;
288 }
289 
290 /// Check whether a personality function could reasonably be swapped
291 /// for a C++ personality function.
292 static bool PersonalityHasOnlyCXXUses(llvm::Constant *Fn) {
293  for (llvm::User *U : Fn->users()) {
294  // Conditionally white-list bitcasts.
295  if (llvm::ConstantExpr *CE = dyn_cast<llvm::ConstantExpr>(U)) {
296  if (CE->getOpcode() != llvm::Instruction::BitCast) return false;
297  if (!PersonalityHasOnlyCXXUses(CE))
298  return false;
299  continue;
300  }
301 
302  // Otherwise it must be a function.
303  llvm::Function *F = dyn_cast<llvm::Function>(U);
304  if (!F) return false;
305 
306  for (auto BB = F->begin(), E = F->end(); BB != E; ++BB) {
307  if (BB->isLandingPad())
308  if (!LandingPadHasOnlyCXXUses(BB->getLandingPadInst()))
309  return false;
310  }
311  }
312 
313  return true;
314 }
315 
316 /// Try to use the C++ personality function in ObjC++. Not doing this
317 /// can cause some incompatibilities with gcc, which is more
318 /// aggressive about only using the ObjC++ personality in a function
319 /// when it really needs it.
320 void CodeGenModule::SimplifyPersonality() {
321  // If we're not in ObjC++ -fexceptions, there's nothing to do.
322  if (!LangOpts.CPlusPlus || !LangOpts.ObjC || !LangOpts.Exceptions)
323  return;
324 
325  // Both the problem this endeavors to fix and the way the logic
326  // above works is specific to the NeXT runtime.
327  if (!LangOpts.ObjCRuntime.isNeXTFamily())
328  return;
329 
330  const EHPersonality &ObjCXX = EHPersonality::get(*this, /*FD=*/nullptr);
331  const EHPersonality &CXX = getCXXPersonality(getTarget(), LangOpts);
332  if (&ObjCXX == &CXX)
333  return;
334 
335  assert(std::strcmp(ObjCXX.PersonalityFn, CXX.PersonalityFn) != 0 &&
336  "Different EHPersonalities using the same personality function.");
337 
338  llvm::Function *Fn = getModule().getFunction(ObjCXX.PersonalityFn);
339 
340  // Nothing to do if it's unused.
341  if (!Fn || Fn->use_empty()) return;
342 
343  // Can't do the optimization if it has non-C++ uses.
344  if (!PersonalityHasOnlyCXXUses(Fn)) return;
345 
346  // Create the C++ personality function and kill off the old
347  // function.
348  llvm::Constant *CXXFn = getPersonalityFn(*this, CXX);
349 
350  // This can happen if the user is screwing with us.
351  if (Fn->getType() != CXXFn->getType()) return;
352 
353  Fn->replaceAllUsesWith(CXXFn);
354  Fn->eraseFromParent();
355 }
356 
357 /// Returns the value to inject into a selector to indicate the
358 /// presence of a catch-all.
359 static llvm::Constant *getCatchAllValue(CodeGenFunction &CGF) {
360  // Possibly we should use @llvm.eh.catch.all.value here.
361  return llvm::ConstantPointerNull::get(CGF.Int8PtrTy);
362 }
363 
364 namespace {
365  /// A cleanup to free the exception object if its initialization
366  /// throws.
367  struct FreeException final : EHScopeStack::Cleanup {
368  llvm::Value *exn;
369  FreeException(llvm::Value *exn) : exn(exn) {}
370  void Emit(CodeGenFunction &CGF, Flags flags) override {
372  }
373  };
374 } // end anonymous namespace
375 
376 // Emits an exception expression into the given location. This
377 // differs from EmitAnyExprToMem only in that, if a final copy-ctor
378 // call is required, an exception within that copy ctor causes
379 // std::terminate to be invoked.
381  // Make sure the exception object is cleaned up if there's an
382  // exception during initialization.
383  pushFullExprCleanup<FreeException>(EHCleanup, addr.getPointer());
384  EHScopeStack::stable_iterator cleanup = EHStack.stable_begin();
385 
386  // __cxa_allocate_exception returns a void*; we need to cast this
387  // to the appropriate type for the object.
388  llvm::Type *ty = ConvertTypeForMem(e->getType())->getPointerTo();
389  Address typedAddr = Builder.CreateBitCast(addr, ty);
390 
391  // FIXME: this isn't quite right! If there's a final unelided call
392  // to a copy constructor, then according to [except.terminate]p1 we
393  // must call std::terminate() if that constructor throws, because
394  // technically that copy occurs after the exception expression is
395  // evaluated but before the exception is caught. But the best way
396  // to handle that is to teach EmitAggExpr to do the final copy
397  // differently if it can't be elided.
398  EmitAnyExprToMem(e, typedAddr, e->getType().getQualifiers(),
399  /*IsInit*/ true);
400 
401  // Deactivate the cleanup block.
402  DeactivateCleanupBlock(cleanup,
403  cast<llvm::Instruction>(typedAddr.getPointer()));
404 }
405 
407  if (!ExceptionSlot)
408  ExceptionSlot = CreateTempAlloca(Int8PtrTy, "exn.slot");
409  return Address(ExceptionSlot, getPointerAlign());
410 }
411 
413  if (!EHSelectorSlot)
414  EHSelectorSlot = CreateTempAlloca(Int32Ty, "ehselector.slot");
415  return Address(EHSelectorSlot, CharUnits::fromQuantity(4));
416 }
417 
419  return Builder.CreateLoad(getExceptionSlot(), "exn");
420 }
421 
423  return Builder.CreateLoad(getEHSelectorSlot(), "sel");
424 }
425 
427  bool KeepInsertionPoint) {
428  if (const Expr *SubExpr = E->getSubExpr()) {
429  QualType ThrowType = SubExpr->getType();
430  if (ThrowType->isObjCObjectPointerType()) {
431  const Stmt *ThrowStmt = E->getSubExpr();
432  const ObjCAtThrowStmt S(E->getExprLoc(), const_cast<Stmt *>(ThrowStmt));
433  CGM.getObjCRuntime().EmitThrowStmt(*this, S, false);
434  } else {
435  CGM.getCXXABI().emitThrow(*this, E);
436  }
437  } else {
438  CGM.getCXXABI().emitRethrow(*this, /*isNoReturn=*/true);
439  }
440 
441  // throw is an expression, and the expression emitters expect us
442  // to leave ourselves at a valid insertion point.
443  if (KeepInsertionPoint)
444  EmitBlock(createBasicBlock("throw.cont"));
445 }
446 
448  if (!CGM.getLangOpts().CXXExceptions)
449  return;
450 
451  const FunctionDecl* FD = dyn_cast_or_null<FunctionDecl>(D);
452  if (!FD) {
453  // Check if CapturedDecl is nothrow and create terminate scope for it.
454  if (const CapturedDecl* CD = dyn_cast_or_null<CapturedDecl>(D)) {
455  if (CD->isNothrow())
456  EHStack.pushTerminate();
457  }
458  return;
459  }
460  const FunctionProtoType *Proto = FD->getType()->getAs<FunctionProtoType>();
461  if (!Proto)
462  return;
463 
465  if (isNoexceptExceptionSpec(EST) && Proto->canThrow() == CT_Cannot) {
466  // noexcept functions are simple terminate scopes.
467  EHStack.pushTerminate();
468  } else if (EST == EST_Dynamic || EST == EST_DynamicNone) {
469  // TODO: Revisit exception specifications for the MS ABI. There is a way to
470  // encode these in an object file but MSVC doesn't do anything with it.
471  if (getTarget().getCXXABI().isMicrosoft())
472  return;
473  unsigned NumExceptions = Proto->getNumExceptions();
474  EHFilterScope *Filter = EHStack.pushFilter(NumExceptions);
475 
476  for (unsigned I = 0; I != NumExceptions; ++I) {
477  QualType Ty = Proto->getExceptionType(I);
478  QualType ExceptType = Ty.getNonReferenceType().getUnqualifiedType();
479  llvm::Value *EHType = CGM.GetAddrOfRTTIDescriptor(ExceptType,
480  /*ForEH=*/true);
481  Filter->setFilter(I, EHType);
482  }
483  }
484 }
485 
486 /// Emit the dispatch block for a filter scope if necessary.
488  EHFilterScope &filterScope) {
489  llvm::BasicBlock *dispatchBlock = filterScope.getCachedEHDispatchBlock();
490  if (!dispatchBlock) return;
491  if (dispatchBlock->use_empty()) {
492  delete dispatchBlock;
493  return;
494  }
495 
496  CGF.EmitBlockAfterUses(dispatchBlock);
497 
498  // If this isn't a catch-all filter, we need to check whether we got
499  // here because the filter triggered.
500  if (filterScope.getNumFilters()) {
501  // Load the selector value.
502  llvm::Value *selector = CGF.getSelectorFromSlot();
503  llvm::BasicBlock *unexpectedBB = CGF.createBasicBlock("ehspec.unexpected");
504 
505  llvm::Value *zero = CGF.Builder.getInt32(0);
506  llvm::Value *failsFilter =
507  CGF.Builder.CreateICmpSLT(selector, zero, "ehspec.fails");
508  CGF.Builder.CreateCondBr(failsFilter, unexpectedBB,
509  CGF.getEHResumeBlock(false));
510 
511  CGF.EmitBlock(unexpectedBB);
512  }
513 
514  // Call __cxa_call_unexpected. This doesn't need to be an invoke
515  // because __cxa_call_unexpected magically filters exceptions
516  // according to the last landing pad the exception was thrown
517  // into. Seriously.
518  llvm::Value *exn = CGF.getExceptionFromSlot();
519  CGF.EmitRuntimeCall(getUnexpectedFn(CGF.CGM), exn)
520  ->setDoesNotReturn();
521  CGF.Builder.CreateUnreachable();
522 }
523 
525  if (!CGM.getLangOpts().CXXExceptions)
526  return;
527 
528  const FunctionDecl* FD = dyn_cast_or_null<FunctionDecl>(D);
529  if (!FD) {
530  // Check if CapturedDecl is nothrow and pop terminate scope for it.
531  if (const CapturedDecl* CD = dyn_cast_or_null<CapturedDecl>(D)) {
532  if (CD->isNothrow())
533  EHStack.popTerminate();
534  }
535  return;
536  }
537  const FunctionProtoType *Proto = FD->getType()->getAs<FunctionProtoType>();
538  if (!Proto)
539  return;
540 
542  if (isNoexceptExceptionSpec(EST) && Proto->canThrow() == CT_Cannot) {
543  EHStack.popTerminate();
544  } else if (EST == EST_Dynamic || EST == EST_DynamicNone) {
545  // TODO: Revisit exception specifications for the MS ABI. There is a way to
546  // encode these in an object file but MSVC doesn't do anything with it.
547  if (getTarget().getCXXABI().isMicrosoft())
548  return;
549  EHFilterScope &filterScope = cast<EHFilterScope>(*EHStack.begin());
550  emitFilterDispatchBlock(*this, filterScope);
551  EHStack.popFilter();
552  }
553 }
554 
556  EnterCXXTryStmt(S);
557  EmitStmt(S.getTryBlock());
558  ExitCXXTryStmt(S);
559 }
560 
561 void CodeGenFunction::EnterCXXTryStmt(const CXXTryStmt &S, bool IsFnTryBlock) {
562  unsigned NumHandlers = S.getNumHandlers();
563  EHCatchScope *CatchScope = EHStack.pushCatch(NumHandlers);
564 
565  for (unsigned I = 0; I != NumHandlers; ++I) {
566  const CXXCatchStmt *C = S.getHandler(I);
567 
568  llvm::BasicBlock *Handler = createBasicBlock("catch");
569  if (C->getExceptionDecl()) {
570  // FIXME: Dropping the reference type on the type into makes it
571  // impossible to correctly implement catch-by-reference
572  // semantics for pointers. Unfortunately, this is what all
573  // existing compilers do, and it's not clear that the standard
574  // personality routine is capable of doing this right. See C++ DR 388:
575  // http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#388
576  Qualifiers CaughtTypeQuals;
577  QualType CaughtType = CGM.getContext().getUnqualifiedArrayType(
578  C->getCaughtType().getNonReferenceType(), CaughtTypeQuals);
579 
580  CatchTypeInfo TypeInfo{nullptr, 0};
581  if (CaughtType->isObjCObjectPointerType())
582  TypeInfo.RTTI = CGM.getObjCRuntime().GetEHType(CaughtType);
583  else
584  TypeInfo = CGM.getCXXABI().getAddrOfCXXCatchHandlerType(
585  CaughtType, C->getCaughtType());
586  CatchScope->setHandler(I, TypeInfo, Handler);
587  } else {
588  // No exception decl indicates '...', a catch-all.
589  CatchScope->setHandler(I, CGM.getCXXABI().getCatchAllTypeInfo(), Handler);
590  }
591  }
592 }
593 
594 llvm::BasicBlock *
596  if (EHPersonality::get(*this).usesFuncletPads())
597  return getFuncletEHDispatchBlock(si);
598 
599  // The dispatch block for the end of the scope chain is a block that
600  // just resumes unwinding.
601  if (si == EHStack.stable_end())
602  return getEHResumeBlock(true);
603 
604  // Otherwise, we should look at the actual scope.
605  EHScope &scope = *EHStack.find(si);
606 
607  llvm::BasicBlock *dispatchBlock = scope.getCachedEHDispatchBlock();
608  if (!dispatchBlock) {
609  switch (scope.getKind()) {
610  case EHScope::Catch: {
611  // Apply a special case to a single catch-all.
612  EHCatchScope &catchScope = cast<EHCatchScope>(scope);
613  if (catchScope.getNumHandlers() == 1 &&
614  catchScope.getHandler(0).isCatchAll()) {
615  dispatchBlock = catchScope.getHandler(0).Block;
616 
617  // Otherwise, make a dispatch block.
618  } else {
619  dispatchBlock = createBasicBlock("catch.dispatch");
620  }
621  break;
622  }
623 
624  case EHScope::Cleanup:
625  dispatchBlock = createBasicBlock("ehcleanup");
626  break;
627 
628  case EHScope::Filter:
629  dispatchBlock = createBasicBlock("filter.dispatch");
630  break;
631 
632  case EHScope::Terminate:
633  dispatchBlock = getTerminateHandler();
634  break;
635 
636  case EHScope::PadEnd:
637  llvm_unreachable("PadEnd unnecessary for Itanium!");
638  }
639  scope.setCachedEHDispatchBlock(dispatchBlock);
640  }
641  return dispatchBlock;
642 }
643 
644 llvm::BasicBlock *
646  // Returning nullptr indicates that the previous dispatch block should unwind
647  // to caller.
648  if (SI == EHStack.stable_end())
649  return nullptr;
650 
651  // Otherwise, we should look at the actual scope.
652  EHScope &EHS = *EHStack.find(SI);
653 
654  llvm::BasicBlock *DispatchBlock = EHS.getCachedEHDispatchBlock();
655  if (DispatchBlock)
656  return DispatchBlock;
657 
658  if (EHS.getKind() == EHScope::Terminate)
659  DispatchBlock = getTerminateFunclet();
660  else
661  DispatchBlock = createBasicBlock();
662  CGBuilderTy Builder(*this, DispatchBlock);
663 
664  switch (EHS.getKind()) {
665  case EHScope::Catch:
666  DispatchBlock->setName("catch.dispatch");
667  break;
668 
669  case EHScope::Cleanup:
670  DispatchBlock->setName("ehcleanup");
671  break;
672 
673  case EHScope::Filter:
674  llvm_unreachable("exception specifications not handled yet!");
675 
676  case EHScope::Terminate:
677  DispatchBlock->setName("terminate");
678  break;
679 
680  case EHScope::PadEnd:
681  llvm_unreachable("PadEnd dispatch block missing!");
682  }
683  EHS.setCachedEHDispatchBlock(DispatchBlock);
684  return DispatchBlock;
685 }
686 
687 /// Check whether this is a non-EH scope, i.e. a scope which doesn't
688 /// affect exception handling. Currently, the only non-EH scopes are
689 /// normal-only cleanup scopes.
690 static bool isNonEHScope(const EHScope &S) {
691  switch (S.getKind()) {
692  case EHScope::Cleanup:
693  return !cast<EHCleanupScope>(S).isEHCleanup();
694  case EHScope::Filter:
695  case EHScope::Catch:
696  case EHScope::Terminate:
697  case EHScope::PadEnd:
698  return false;
699  }
700 
701  llvm_unreachable("Invalid EHScope Kind!");
702 }
703 
705  assert(EHStack.requiresLandingPad());
706  assert(!EHStack.empty());
707 
708  // If exceptions are disabled and SEH is not in use, then there is no invoke
709  // destination. SEH "works" even if exceptions are off. In practice, this
710  // means that C++ destructors and other EH cleanups don't run, which is
711  // consistent with MSVC's behavior.
712  const LangOptions &LO = CGM.getLangOpts();
713  if (!LO.Exceptions) {
714  if (!LO.Borland && !LO.MicrosoftExt)
715  return nullptr;
716  if (!currentFunctionUsesSEHTry())
717  return nullptr;
718  }
719 
720  // CUDA device code doesn't have exceptions.
721  if (LO.CUDA && LO.CUDAIsDevice)
722  return nullptr;
723 
724  // Check the innermost scope for a cached landing pad. If this is
725  // a non-EH cleanup, we'll check enclosing scopes in EmitLandingPad.
726  llvm::BasicBlock *LP = EHStack.begin()->getCachedLandingPad();
727  if (LP) return LP;
728 
729  const EHPersonality &Personality = EHPersonality::get(*this);
730 
731  if (!CurFn->hasPersonalityFn())
732  CurFn->setPersonalityFn(getOpaquePersonalityFn(CGM, Personality));
733 
734  if (Personality.usesFuncletPads()) {
735  // We don't need separate landing pads in the funclet model.
736  LP = getEHDispatchBlock(EHStack.getInnermostEHScope());
737  } else {
738  // Build the landing pad for this scope.
739  LP = EmitLandingPad();
740  }
741 
742  assert(LP);
743 
744  // Cache the landing pad on the innermost scope. If this is a
745  // non-EH scope, cache the landing pad on the enclosing scope, too.
746  for (EHScopeStack::iterator ir = EHStack.begin(); true; ++ir) {
747  ir->setCachedLandingPad(LP);
748  if (!isNonEHScope(*ir)) break;
749  }
750 
751  return LP;
752 }
753 
754 llvm::BasicBlock *CodeGenFunction::EmitLandingPad() {
755  assert(EHStack.requiresLandingPad());
756 
757  EHScope &innermostEHScope = *EHStack.find(EHStack.getInnermostEHScope());
758  switch (innermostEHScope.getKind()) {
759  case EHScope::Terminate:
760  return getTerminateLandingPad();
761 
762  case EHScope::PadEnd:
763  llvm_unreachable("PadEnd unnecessary for Itanium!");
764 
765  case EHScope::Catch:
766  case EHScope::Cleanup:
767  case EHScope::Filter:
768  if (llvm::BasicBlock *lpad = innermostEHScope.getCachedLandingPad())
769  return lpad;
770  }
771 
772  // Save the current IR generation state.
773  CGBuilderTy::InsertPoint savedIP = Builder.saveAndClearIP();
774  auto DL = ApplyDebugLocation::CreateDefaultArtificial(*this, CurEHLocation);
775 
776  // Create and configure the landing pad.
777  llvm::BasicBlock *lpad = createBasicBlock("lpad");
778  EmitBlock(lpad);
779 
780  llvm::LandingPadInst *LPadInst =
781  Builder.CreateLandingPad(llvm::StructType::get(Int8PtrTy, Int32Ty), 0);
782 
783  llvm::Value *LPadExn = Builder.CreateExtractValue(LPadInst, 0);
784  Builder.CreateStore(LPadExn, getExceptionSlot());
785  llvm::Value *LPadSel = Builder.CreateExtractValue(LPadInst, 1);
786  Builder.CreateStore(LPadSel, getEHSelectorSlot());
787 
788  // Save the exception pointer. It's safe to use a single exception
789  // pointer per function because EH cleanups can never have nested
790  // try/catches.
791  // Build the landingpad instruction.
792 
793  // Accumulate all the handlers in scope.
794  bool hasCatchAll = false;
795  bool hasCleanup = false;
796  bool hasFilter = false;
797  SmallVector<llvm::Value*, 4> filterTypes;
798  llvm::SmallPtrSet<llvm::Value*, 4> catchTypes;
799  for (EHScopeStack::iterator I = EHStack.begin(), E = EHStack.end(); I != E;
800  ++I) {
801 
802  switch (I->getKind()) {
803  case EHScope::Cleanup:
804  // If we have a cleanup, remember that.
805  hasCleanup = (hasCleanup || cast<EHCleanupScope>(*I).isEHCleanup());
806  continue;
807 
808  case EHScope::Filter: {
809  assert(I.next() == EHStack.end() && "EH filter is not end of EH stack");
810  assert(!hasCatchAll && "EH filter reached after catch-all");
811 
812  // Filter scopes get added to the landingpad in weird ways.
813  EHFilterScope &filter = cast<EHFilterScope>(*I);
814  hasFilter = true;
815 
816  // Add all the filter values.
817  for (unsigned i = 0, e = filter.getNumFilters(); i != e; ++i)
818  filterTypes.push_back(filter.getFilter(i));
819  goto done;
820  }
821 
822  case EHScope::Terminate:
823  // Terminate scopes are basically catch-alls.
824  assert(!hasCatchAll);
825  hasCatchAll = true;
826  goto done;
827 
828  case EHScope::Catch:
829  break;
830 
831  case EHScope::PadEnd:
832  llvm_unreachable("PadEnd unnecessary for Itanium!");
833  }
834 
835  EHCatchScope &catchScope = cast<EHCatchScope>(*I);
836  for (unsigned hi = 0, he = catchScope.getNumHandlers(); hi != he; ++hi) {
837  EHCatchScope::Handler handler = catchScope.getHandler(hi);
838  assert(handler.Type.Flags == 0 &&
839  "landingpads do not support catch handler flags");
840 
841  // If this is a catch-all, register that and abort.
842  if (!handler.Type.RTTI) {
843  assert(!hasCatchAll);
844  hasCatchAll = true;
845  goto done;
846  }
847 
848  // Check whether we already have a handler for this type.
849  if (catchTypes.insert(handler.Type.RTTI).second)
850  // If not, add it directly to the landingpad.
851  LPadInst->addClause(handler.Type.RTTI);
852  }
853  }
854 
855  done:
856  // If we have a catch-all, add null to the landingpad.
857  assert(!(hasCatchAll && hasFilter));
858  if (hasCatchAll) {
859  LPadInst->addClause(getCatchAllValue(*this));
860 
861  // If we have an EH filter, we need to add those handlers in the
862  // right place in the landingpad, which is to say, at the end.
863  } else if (hasFilter) {
864  // Create a filter expression: a constant array indicating which filter
865  // types there are. The personality routine only lands here if the filter
866  // doesn't match.
868  llvm::ArrayType *AType =
869  llvm::ArrayType::get(!filterTypes.empty() ?
870  filterTypes[0]->getType() : Int8PtrTy,
871  filterTypes.size());
872 
873  for (unsigned i = 0, e = filterTypes.size(); i != e; ++i)
874  Filters.push_back(cast<llvm::Constant>(filterTypes[i]));
875  llvm::Constant *FilterArray = llvm::ConstantArray::get(AType, Filters);
876  LPadInst->addClause(FilterArray);
877 
878  // Also check whether we need a cleanup.
879  if (hasCleanup)
880  LPadInst->setCleanup(true);
881 
882  // Otherwise, signal that we at least have cleanups.
883  } else if (hasCleanup) {
884  LPadInst->setCleanup(true);
885  }
886 
887  assert((LPadInst->getNumClauses() > 0 || LPadInst->isCleanup()) &&
888  "landingpad instruction has no clauses!");
889 
890  // Tell the backend how to generate the landing pad.
891  Builder.CreateBr(getEHDispatchBlock(EHStack.getInnermostEHScope()));
892 
893  // Restore the old IR generation state.
894  Builder.restoreIP(savedIP);
895 
896  return lpad;
897 }
898 
899 static void emitCatchPadBlock(CodeGenFunction &CGF, EHCatchScope &CatchScope) {
900  llvm::BasicBlock *DispatchBlock = CatchScope.getCachedEHDispatchBlock();
901  assert(DispatchBlock);
902 
903  CGBuilderTy::InsertPoint SavedIP = CGF.Builder.saveIP();
904  CGF.EmitBlockAfterUses(DispatchBlock);
905 
906  llvm::Value *ParentPad = CGF.CurrentFuncletPad;
907  if (!ParentPad)
908  ParentPad = llvm::ConstantTokenNone::get(CGF.getLLVMContext());
909  llvm::BasicBlock *UnwindBB =
910  CGF.getEHDispatchBlock(CatchScope.getEnclosingEHScope());
911 
912  unsigned NumHandlers = CatchScope.getNumHandlers();
913  llvm::CatchSwitchInst *CatchSwitch =
914  CGF.Builder.CreateCatchSwitch(ParentPad, UnwindBB, NumHandlers);
915 
916  // Test against each of the exception types we claim to catch.
917  for (unsigned I = 0; I < NumHandlers; ++I) {
918  const EHCatchScope::Handler &Handler = CatchScope.getHandler(I);
919 
920  CatchTypeInfo TypeInfo = Handler.Type;
921  if (!TypeInfo.RTTI)
922  TypeInfo.RTTI = llvm::Constant::getNullValue(CGF.VoidPtrTy);
923 
924  CGF.Builder.SetInsertPoint(Handler.Block);
925 
926  if (EHPersonality::get(CGF).isMSVCXXPersonality()) {
927  CGF.Builder.CreateCatchPad(
928  CatchSwitch, {TypeInfo.RTTI, CGF.Builder.getInt32(TypeInfo.Flags),
929  llvm::Constant::getNullValue(CGF.VoidPtrTy)});
930  } else {
931  CGF.Builder.CreateCatchPad(CatchSwitch, {TypeInfo.RTTI});
932  }
933 
934  CatchSwitch->addHandler(Handler.Block);
935  }
936  CGF.Builder.restoreIP(SavedIP);
937 }
938 
939 // Wasm uses Windows-style EH instructions, but it merges all catch clauses into
940 // one big catchpad, within which we use Itanium's landingpad-style selector
941 // comparison instructions.
943  EHCatchScope &CatchScope) {
944  llvm::BasicBlock *DispatchBlock = CatchScope.getCachedEHDispatchBlock();
945  assert(DispatchBlock);
946 
947  CGBuilderTy::InsertPoint SavedIP = CGF.Builder.saveIP();
948  CGF.EmitBlockAfterUses(DispatchBlock);
949 
950  llvm::Value *ParentPad = CGF.CurrentFuncletPad;
951  if (!ParentPad)
952  ParentPad = llvm::ConstantTokenNone::get(CGF.getLLVMContext());
953  llvm::BasicBlock *UnwindBB =
954  CGF.getEHDispatchBlock(CatchScope.getEnclosingEHScope());
955 
956  unsigned NumHandlers = CatchScope.getNumHandlers();
957  llvm::CatchSwitchInst *CatchSwitch =
958  CGF.Builder.CreateCatchSwitch(ParentPad, UnwindBB, NumHandlers);
959 
960  // We don't use a landingpad instruction, so generate intrinsic calls to
961  // provide exception and selector values.
962  llvm::BasicBlock *WasmCatchStartBlock = CGF.createBasicBlock("catch.start");
963  CatchSwitch->addHandler(WasmCatchStartBlock);
964  CGF.EmitBlockAfterUses(WasmCatchStartBlock);
965 
966  // Create a catchpad instruction.
968  for (unsigned I = 0, E = NumHandlers; I < E; ++I) {
969  const EHCatchScope::Handler &Handler = CatchScope.getHandler(I);
970  CatchTypeInfo TypeInfo = Handler.Type;
971  if (!TypeInfo.RTTI)
972  TypeInfo.RTTI = llvm::Constant::getNullValue(CGF.VoidPtrTy);
973  CatchTypes.push_back(TypeInfo.RTTI);
974  }
975  auto *CPI = CGF.Builder.CreateCatchPad(CatchSwitch, CatchTypes);
976 
977  // Create calls to wasm.get.exception and wasm.get.ehselector intrinsics.
978  // Before they are lowered appropriately later, they provide values for the
979  // exception and selector.
980  llvm::Value *GetExnFn =
981  CGF.CGM.getIntrinsic(llvm::Intrinsic::wasm_get_exception);
982  llvm::Value *GetSelectorFn =
983  CGF.CGM.getIntrinsic(llvm::Intrinsic::wasm_get_ehselector);
984  llvm::CallInst *Exn = CGF.Builder.CreateCall(GetExnFn, CPI);
985  CGF.Builder.CreateStore(Exn, CGF.getExceptionSlot());
986  llvm::CallInst *Selector = CGF.Builder.CreateCall(GetSelectorFn, CPI);
987 
988  llvm::Value *TypeIDFn = CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_typeid_for);
989 
990  // If there's only a single catch-all, branch directly to its handler.
991  if (CatchScope.getNumHandlers() == 1 &&
992  CatchScope.getHandler(0).isCatchAll()) {
993  CGF.Builder.CreateBr(CatchScope.getHandler(0).Block);
994  CGF.Builder.restoreIP(SavedIP);
995  return;
996  }
997 
998  // Test against each of the exception types we claim to catch.
999  for (unsigned I = 0, E = NumHandlers;; ++I) {
1000  assert(I < E && "ran off end of handlers!");
1001  const EHCatchScope::Handler &Handler = CatchScope.getHandler(I);
1002  CatchTypeInfo TypeInfo = Handler.Type;
1003  if (!TypeInfo.RTTI)
1004  TypeInfo.RTTI = llvm::Constant::getNullValue(CGF.VoidPtrTy);
1005 
1006  // Figure out the next block.
1007  llvm::BasicBlock *NextBlock;
1008 
1009  bool EmitNextBlock = false, NextIsEnd = false;
1010 
1011  // If this is the last handler, we're at the end, and the next block is a
1012  // block that contains a call to the rethrow function, so we can unwind to
1013  // the enclosing EH scope. The call itself will be generated later.
1014  if (I + 1 == E) {
1015  NextBlock = CGF.createBasicBlock("rethrow");
1016  EmitNextBlock = true;
1017  NextIsEnd = true;
1018 
1019  // If the next handler is a catch-all, we're at the end, and the
1020  // next block is that handler.
1021  } else if (CatchScope.getHandler(I + 1).isCatchAll()) {
1022  NextBlock = CatchScope.getHandler(I + 1).Block;
1023  NextIsEnd = true;
1024 
1025  // Otherwise, we're not at the end and we need a new block.
1026  } else {
1027  NextBlock = CGF.createBasicBlock("catch.fallthrough");
1028  EmitNextBlock = true;
1029  }
1030 
1031  // Figure out the catch type's index in the LSDA's type table.
1032  llvm::CallInst *TypeIndex = CGF.Builder.CreateCall(TypeIDFn, TypeInfo.RTTI);
1033  TypeIndex->setDoesNotThrow();
1034 
1035  llvm::Value *MatchesTypeIndex =
1036  CGF.Builder.CreateICmpEQ(Selector, TypeIndex, "matches");
1037  CGF.Builder.CreateCondBr(MatchesTypeIndex, Handler.Block, NextBlock);
1038 
1039  if (EmitNextBlock)
1040  CGF.EmitBlock(NextBlock);
1041  if (NextIsEnd)
1042  break;
1043  }
1044 
1045  CGF.Builder.restoreIP(SavedIP);
1046 }
1047 
1048 /// Emit the structure of the dispatch block for the given catch scope.
1049 /// It is an invariant that the dispatch block already exists.
1051  EHCatchScope &catchScope) {
1052  if (EHPersonality::get(CGF).isWasmPersonality())
1053  return emitWasmCatchPadBlock(CGF, catchScope);
1054  if (EHPersonality::get(CGF).usesFuncletPads())
1055  return emitCatchPadBlock(CGF, catchScope);
1056 
1057  llvm::BasicBlock *dispatchBlock = catchScope.getCachedEHDispatchBlock();
1058  assert(dispatchBlock);
1059 
1060  // If there's only a single catch-all, getEHDispatchBlock returned
1061  // that catch-all as the dispatch block.
1062  if (catchScope.getNumHandlers() == 1 &&
1063  catchScope.getHandler(0).isCatchAll()) {
1064  assert(dispatchBlock == catchScope.getHandler(0).Block);
1065  return;
1066  }
1067 
1068  CGBuilderTy::InsertPoint savedIP = CGF.Builder.saveIP();
1069  CGF.EmitBlockAfterUses(dispatchBlock);
1070 
1071  // Select the right handler.
1072  llvm::Value *llvm_eh_typeid_for =
1073  CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_typeid_for);
1074 
1075  // Load the selector value.
1076  llvm::Value *selector = CGF.getSelectorFromSlot();
1077 
1078  // Test against each of the exception types we claim to catch.
1079  for (unsigned i = 0, e = catchScope.getNumHandlers(); ; ++i) {
1080  assert(i < e && "ran off end of handlers!");
1081  const EHCatchScope::Handler &handler = catchScope.getHandler(i);
1082 
1083  llvm::Value *typeValue = handler.Type.RTTI;
1084  assert(handler.Type.Flags == 0 &&
1085  "landingpads do not support catch handler flags");
1086  assert(typeValue && "fell into catch-all case!");
1087  typeValue = CGF.Builder.CreateBitCast(typeValue, CGF.Int8PtrTy);
1088 
1089  // Figure out the next block.
1090  bool nextIsEnd;
1091  llvm::BasicBlock *nextBlock;
1092 
1093  // If this is the last handler, we're at the end, and the next
1094  // block is the block for the enclosing EH scope.
1095  if (i + 1 == e) {
1096  nextBlock = CGF.getEHDispatchBlock(catchScope.getEnclosingEHScope());
1097  nextIsEnd = true;
1098 
1099  // If the next handler is a catch-all, we're at the end, and the
1100  // next block is that handler.
1101  } else if (catchScope.getHandler(i+1).isCatchAll()) {
1102  nextBlock = catchScope.getHandler(i+1).Block;
1103  nextIsEnd = true;
1104 
1105  // Otherwise, we're not at the end and we need a new block.
1106  } else {
1107  nextBlock = CGF.createBasicBlock("catch.fallthrough");
1108  nextIsEnd = false;
1109  }
1110 
1111  // Figure out the catch type's index in the LSDA's type table.
1112  llvm::CallInst *typeIndex =
1113  CGF.Builder.CreateCall(llvm_eh_typeid_for, typeValue);
1114  typeIndex->setDoesNotThrow();
1115 
1116  llvm::Value *matchesTypeIndex =
1117  CGF.Builder.CreateICmpEQ(selector, typeIndex, "matches");
1118  CGF.Builder.CreateCondBr(matchesTypeIndex, handler.Block, nextBlock);
1119 
1120  // If the next handler is a catch-all, we're completely done.
1121  if (nextIsEnd) {
1122  CGF.Builder.restoreIP(savedIP);
1123  return;
1124  }
1125  // Otherwise we need to emit and continue at that block.
1126  CGF.EmitBlock(nextBlock);
1127  }
1128 }
1129 
1131  EHCatchScope &catchScope = cast<EHCatchScope>(*EHStack.begin());
1132  if (catchScope.hasEHBranches())
1133  emitCatchDispatchBlock(*this, catchScope);
1134  EHStack.popCatch();
1135 }
1136 
1137 void CodeGenFunction::ExitCXXTryStmt(const CXXTryStmt &S, bool IsFnTryBlock) {
1138  unsigned NumHandlers = S.getNumHandlers();
1139  EHCatchScope &CatchScope = cast<EHCatchScope>(*EHStack.begin());
1140  assert(CatchScope.getNumHandlers() == NumHandlers);
1141  llvm::BasicBlock *DispatchBlock = CatchScope.getCachedEHDispatchBlock();
1142 
1143  // If the catch was not required, bail out now.
1144  if (!CatchScope.hasEHBranches()) {
1145  CatchScope.clearHandlerBlocks();
1146  EHStack.popCatch();
1147  return;
1148  }
1149 
1150  // Emit the structure of the EH dispatch for this catch.
1151  emitCatchDispatchBlock(*this, CatchScope);
1152 
1153  // Copy the handler blocks off before we pop the EH stack. Emitting
1154  // the handlers might scribble on this memory.
1156  CatchScope.begin(), CatchScope.begin() + NumHandlers);
1157 
1158  EHStack.popCatch();
1159 
1160  // The fall-through block.
1161  llvm::BasicBlock *ContBB = createBasicBlock("try.cont");
1162 
1163  // We just emitted the body of the try; jump to the continue block.
1164  if (HaveInsertPoint())
1165  Builder.CreateBr(ContBB);
1166 
1167  // Determine if we need an implicit rethrow for all these catch handlers;
1168  // see the comment below.
1169  bool doImplicitRethrow = false;
1170  if (IsFnTryBlock)
1171  doImplicitRethrow = isa<CXXDestructorDecl>(CurCodeDecl) ||
1172  isa<CXXConstructorDecl>(CurCodeDecl);
1173 
1174  // Wasm uses Windows-style EH instructions, but merges all catch clauses into
1175  // one big catchpad. So we save the old funclet pad here before we traverse
1176  // each catch handler.
1177  SaveAndRestore<llvm::Instruction *> RestoreCurrentFuncletPad(
1178  CurrentFuncletPad);
1179  llvm::BasicBlock *WasmCatchStartBlock = nullptr;
1180  if (EHPersonality::get(*this).isWasmPersonality()) {
1181  auto *CatchSwitch =
1182  cast<llvm::CatchSwitchInst>(DispatchBlock->getFirstNonPHI());
1183  WasmCatchStartBlock = CatchSwitch->hasUnwindDest()
1184  ? CatchSwitch->getSuccessor(1)
1185  : CatchSwitch->getSuccessor(0);
1186  auto *CPI = cast<llvm::CatchPadInst>(WasmCatchStartBlock->getFirstNonPHI());
1187  CurrentFuncletPad = CPI;
1188  }
1189 
1190  // Perversely, we emit the handlers backwards precisely because we
1191  // want them to appear in source order. In all of these cases, the
1192  // catch block will have exactly one predecessor, which will be a
1193  // particular block in the catch dispatch. However, in the case of
1194  // a catch-all, one of the dispatch blocks will branch to two
1195  // different handlers, and EmitBlockAfterUses will cause the second
1196  // handler to be moved before the first.
1197  bool HasCatchAll = false;
1198  for (unsigned I = NumHandlers; I != 0; --I) {
1199  HasCatchAll |= Handlers[I - 1].isCatchAll();
1200  llvm::BasicBlock *CatchBlock = Handlers[I-1].Block;
1201  EmitBlockAfterUses(CatchBlock);
1202 
1203  // Catch the exception if this isn't a catch-all.
1204  const CXXCatchStmt *C = S.getHandler(I-1);
1205 
1206  // Enter a cleanup scope, including the catch variable and the
1207  // end-catch.
1208  RunCleanupsScope CatchScope(*this);
1209 
1210  // Initialize the catch variable and set up the cleanups.
1211  SaveAndRestore<llvm::Instruction *> RestoreCurrentFuncletPad(
1212  CurrentFuncletPad);
1213  CGM.getCXXABI().emitBeginCatch(*this, C);
1214 
1215  // Emit the PGO counter increment.
1216  incrementProfileCounter(C);
1217 
1218  // Perform the body of the catch.
1219  EmitStmt(C->getHandlerBlock());
1220 
1221  // [except.handle]p11:
1222  // The currently handled exception is rethrown if control
1223  // reaches the end of a handler of the function-try-block of a
1224  // constructor or destructor.
1225 
1226  // It is important that we only do this on fallthrough and not on
1227  // return. Note that it's illegal to put a return in a
1228  // constructor function-try-block's catch handler (p14), so this
1229  // really only applies to destructors.
1230  if (doImplicitRethrow && HaveInsertPoint()) {
1231  CGM.getCXXABI().emitRethrow(*this, /*isNoReturn*/false);
1232  Builder.CreateUnreachable();
1233  Builder.ClearInsertionPoint();
1234  }
1235 
1236  // Fall out through the catch cleanups.
1237  CatchScope.ForceCleanup();
1238 
1239  // Branch out of the try.
1240  if (HaveInsertPoint())
1241  Builder.CreateBr(ContBB);
1242  }
1243 
1244  // Because in wasm we merge all catch clauses into one big catchpad, in case
1245  // none of the types in catch handlers matches after we test against each of
1246  // them, we should unwind to the next EH enclosing scope. We generate a call
1247  // to rethrow function here to do that.
1248  if (EHPersonality::get(*this).isWasmPersonality() && !HasCatchAll) {
1249  assert(WasmCatchStartBlock);
1250  // Navigate for the "rethrow" block we created in emitWasmCatchPadBlock().
1251  // Wasm uses landingpad-style conditional branches to compare selectors, so
1252  // we follow the false destination for each of the cond branches to reach
1253  // the rethrow block.
1254  llvm::BasicBlock *RethrowBlock = WasmCatchStartBlock;
1255  while (llvm::Instruction *TI = RethrowBlock->getTerminator()) {
1256  auto *BI = cast<llvm::BranchInst>(TI);
1257  assert(BI->isConditional());
1258  RethrowBlock = BI->getSuccessor(1);
1259  }
1260  assert(RethrowBlock != WasmCatchStartBlock && RethrowBlock->empty());
1261  Builder.SetInsertPoint(RethrowBlock);
1262  CGM.getCXXABI().emitRethrow(*this, /*isNoReturn=*/true);
1263  }
1264 
1265  EmitBlock(ContBB);
1266  incrementProfileCounter(&S);
1267 }
1268 
1269 namespace {
1270  struct CallEndCatchForFinally final : EHScopeStack::Cleanup {
1271  llvm::Value *ForEHVar;
1272  llvm::Value *EndCatchFn;
1273  CallEndCatchForFinally(llvm::Value *ForEHVar, llvm::Value *EndCatchFn)
1274  : ForEHVar(ForEHVar), EndCatchFn(EndCatchFn) {}
1275 
1276  void Emit(CodeGenFunction &CGF, Flags flags) override {
1277  llvm::BasicBlock *EndCatchBB = CGF.createBasicBlock("finally.endcatch");
1278  llvm::BasicBlock *CleanupContBB =
1279  CGF.createBasicBlock("finally.cleanup.cont");
1280 
1281  llvm::Value *ShouldEndCatch =
1282  CGF.Builder.CreateFlagLoad(ForEHVar, "finally.endcatch");
1283  CGF.Builder.CreateCondBr(ShouldEndCatch, EndCatchBB, CleanupContBB);
1284  CGF.EmitBlock(EndCatchBB);
1285  CGF.EmitRuntimeCallOrInvoke(EndCatchFn); // catch-all, so might throw
1286  CGF.EmitBlock(CleanupContBB);
1287  }
1288  };
1289 
1290  struct PerformFinally final : EHScopeStack::Cleanup {
1291  const Stmt *Body;
1292  llvm::Value *ForEHVar;
1293  llvm::Value *EndCatchFn;
1294  llvm::Value *RethrowFn;
1295  llvm::Value *SavedExnVar;
1296 
1297  PerformFinally(const Stmt *Body, llvm::Value *ForEHVar,
1298  llvm::Value *EndCatchFn,
1299  llvm::Value *RethrowFn, llvm::Value *SavedExnVar)
1300  : Body(Body), ForEHVar(ForEHVar), EndCatchFn(EndCatchFn),
1301  RethrowFn(RethrowFn), SavedExnVar(SavedExnVar) {}
1302 
1303  void Emit(CodeGenFunction &CGF, Flags flags) override {
1304  // Enter a cleanup to call the end-catch function if one was provided.
1305  if (EndCatchFn)
1306  CGF.EHStack.pushCleanup<CallEndCatchForFinally>(NormalAndEHCleanup,
1307  ForEHVar, EndCatchFn);
1308 
1309  // Save the current cleanup destination in case there are
1310  // cleanups in the finally block.
1311  llvm::Value *SavedCleanupDest =
1313  "cleanup.dest.saved");
1314 
1315  // Emit the finally block.
1316  CGF.EmitStmt(Body);
1317 
1318  // If the end of the finally is reachable, check whether this was
1319  // for EH. If so, rethrow.
1320  if (CGF.HaveInsertPoint()) {
1321  llvm::BasicBlock *RethrowBB = CGF.createBasicBlock("finally.rethrow");
1322  llvm::BasicBlock *ContBB = CGF.createBasicBlock("finally.cont");
1323 
1324  llvm::Value *ShouldRethrow =
1325  CGF.Builder.CreateFlagLoad(ForEHVar, "finally.shouldthrow");
1326  CGF.Builder.CreateCondBr(ShouldRethrow, RethrowBB, ContBB);
1327 
1328  CGF.EmitBlock(RethrowBB);
1329  if (SavedExnVar) {
1330  CGF.EmitRuntimeCallOrInvoke(RethrowFn,
1331  CGF.Builder.CreateAlignedLoad(SavedExnVar, CGF.getPointerAlign()));
1332  } else {
1333  CGF.EmitRuntimeCallOrInvoke(RethrowFn);
1334  }
1335  CGF.Builder.CreateUnreachable();
1336 
1337  CGF.EmitBlock(ContBB);
1338 
1339  // Restore the cleanup destination.
1340  CGF.Builder.CreateStore(SavedCleanupDest,
1341  CGF.getNormalCleanupDestSlot());
1342  }
1343 
1344  // Leave the end-catch cleanup. As an optimization, pretend that
1345  // the fallthrough path was inaccessible; we've dynamically proven
1346  // that we're not in the EH case along that path.
1347  if (EndCatchFn) {
1348  CGBuilderTy::InsertPoint SavedIP = CGF.Builder.saveAndClearIP();
1349  CGF.PopCleanupBlock();
1350  CGF.Builder.restoreIP(SavedIP);
1351  }
1352 
1353  // Now make sure we actually have an insertion point or the
1354  // cleanup gods will hate us.
1355  CGF.EnsureInsertPoint();
1356  }
1357  };
1358 } // end anonymous namespace
1359 
1360 /// Enters a finally block for an implementation using zero-cost
1361 /// exceptions. This is mostly general, but hard-codes some
1362 /// language/ABI-specific behavior in the catch-all sections.
1364  const Stmt *body,
1365  llvm::Constant *beginCatchFn,
1366  llvm::Constant *endCatchFn,
1367  llvm::Constant *rethrowFn) {
1368  assert((beginCatchFn != nullptr) == (endCatchFn != nullptr) &&
1369  "begin/end catch functions not paired");
1370  assert(rethrowFn && "rethrow function is required");
1371 
1372  BeginCatchFn = beginCatchFn;
1373 
1374  // The rethrow function has one of the following two types:
1375  // void (*)()
1376  // void (*)(void*)
1377  // In the latter case we need to pass it the exception object.
1378  // But we can't use the exception slot because the @finally might
1379  // have a landing pad (which would overwrite the exception slot).
1380  llvm::FunctionType *rethrowFnTy =
1381  cast<llvm::FunctionType>(
1382  cast<llvm::PointerType>(rethrowFn->getType())->getElementType());
1383  SavedExnVar = nullptr;
1384  if (rethrowFnTy->getNumParams())
1385  SavedExnVar = CGF.CreateTempAlloca(CGF.Int8PtrTy, "finally.exn");
1386 
1387  // A finally block is a statement which must be executed on any edge
1388  // out of a given scope. Unlike a cleanup, the finally block may
1389  // contain arbitrary control flow leading out of itself. In
1390  // addition, finally blocks should always be executed, even if there
1391  // are no catch handlers higher on the stack. Therefore, we
1392  // surround the protected scope with a combination of a normal
1393  // cleanup (to catch attempts to break out of the block via normal
1394  // control flow) and an EH catch-all (semantically "outside" any try
1395  // statement to which the finally block might have been attached).
1396  // The finally block itself is generated in the context of a cleanup
1397  // which conditionally leaves the catch-all.
1398 
1399  // Jump destination for performing the finally block on an exception
1400  // edge. We'll never actually reach this block, so unreachable is
1401  // fine.
1402  RethrowDest = CGF.getJumpDestInCurrentScope(CGF.getUnreachableBlock());
1403 
1404  // Whether the finally block is being executed for EH purposes.
1405  ForEHVar = CGF.CreateTempAlloca(CGF.Builder.getInt1Ty(), "finally.for-eh");
1406  CGF.Builder.CreateFlagStore(false, ForEHVar);
1407 
1408  // Enter a normal cleanup which will perform the @finally block.
1409  CGF.EHStack.pushCleanup<PerformFinally>(NormalCleanup, body,
1410  ForEHVar, endCatchFn,
1411  rethrowFn, SavedExnVar);
1412 
1413  // Enter a catch-all scope.
1414  llvm::BasicBlock *catchBB = CGF.createBasicBlock("finally.catchall");
1415  EHCatchScope *catchScope = CGF.EHStack.pushCatch(1);
1416  catchScope->setCatchAllHandler(0, catchBB);
1417 }
1418 
1420  // Leave the finally catch-all.
1421  EHCatchScope &catchScope = cast<EHCatchScope>(*CGF.EHStack.begin());
1422  llvm::BasicBlock *catchBB = catchScope.getHandler(0).Block;
1423 
1424  CGF.popCatchScope();
1425 
1426  // If there are any references to the catch-all block, emit it.
1427  if (catchBB->use_empty()) {
1428  delete catchBB;
1429  } else {
1430  CGBuilderTy::InsertPoint savedIP = CGF.Builder.saveAndClearIP();
1431  CGF.EmitBlock(catchBB);
1432 
1433  llvm::Value *exn = nullptr;
1434 
1435  // If there's a begin-catch function, call it.
1436  if (BeginCatchFn) {
1437  exn = CGF.getExceptionFromSlot();
1438  CGF.EmitNounwindRuntimeCall(BeginCatchFn, exn);
1439  }
1440 
1441  // If we need to remember the exception pointer to rethrow later, do so.
1442  if (SavedExnVar) {
1443  if (!exn) exn = CGF.getExceptionFromSlot();
1444  CGF.Builder.CreateAlignedStore(exn, SavedExnVar, CGF.getPointerAlign());
1445  }
1446 
1447  // Tell the cleanups in the finally block that we're do this for EH.
1448  CGF.Builder.CreateFlagStore(true, ForEHVar);
1449 
1450  // Thread a jump through the finally cleanup.
1451  CGF.EmitBranchThroughCleanup(RethrowDest);
1452 
1453  CGF.Builder.restoreIP(savedIP);
1454  }
1455 
1456  // Finally, leave the @finally cleanup.
1457  CGF.PopCleanupBlock();
1458 }
1459 
1461  if (TerminateLandingPad)
1462  return TerminateLandingPad;
1463 
1464  CGBuilderTy::InsertPoint SavedIP = Builder.saveAndClearIP();
1465 
1466  // This will get inserted at the end of the function.
1467  TerminateLandingPad = createBasicBlock("terminate.lpad");
1468  Builder.SetInsertPoint(TerminateLandingPad);
1469 
1470  // Tell the backend that this is a landing pad.
1471  const EHPersonality &Personality = EHPersonality::get(*this);
1472 
1473  if (!CurFn->hasPersonalityFn())
1474  CurFn->setPersonalityFn(getOpaquePersonalityFn(CGM, Personality));
1475 
1476  llvm::LandingPadInst *LPadInst =
1477  Builder.CreateLandingPad(llvm::StructType::get(Int8PtrTy, Int32Ty), 0);
1478  LPadInst->addClause(getCatchAllValue(*this));
1479 
1480  llvm::Value *Exn = nullptr;
1481  if (getLangOpts().CPlusPlus)
1482  Exn = Builder.CreateExtractValue(LPadInst, 0);
1483  llvm::CallInst *terminateCall =
1484  CGM.getCXXABI().emitTerminateForUnexpectedException(*this, Exn);
1485  terminateCall->setDoesNotReturn();
1486  Builder.CreateUnreachable();
1487 
1488  // Restore the saved insertion state.
1489  Builder.restoreIP(SavedIP);
1490 
1491  return TerminateLandingPad;
1492 }
1493 
1495  if (TerminateHandler)
1496  return TerminateHandler;
1497 
1498  // Set up the terminate handler. This block is inserted at the very
1499  // end of the function by FinishFunction.
1500  TerminateHandler = createBasicBlock("terminate.handler");
1501  CGBuilderTy::InsertPoint SavedIP = Builder.saveAndClearIP();
1502  Builder.SetInsertPoint(TerminateHandler);
1503 
1504  llvm::Value *Exn = nullptr;
1505  if (getLangOpts().CPlusPlus)
1506  Exn = getExceptionFromSlot();
1507  llvm::CallInst *terminateCall =
1508  CGM.getCXXABI().emitTerminateForUnexpectedException(*this, Exn);
1509  terminateCall->setDoesNotReturn();
1510  Builder.CreateUnreachable();
1511 
1512  // Restore the saved insertion state.
1513  Builder.restoreIP(SavedIP);
1514 
1515  return TerminateHandler;
1516 }
1517 
1519  assert(EHPersonality::get(*this).usesFuncletPads() &&
1520  "use getTerminateLandingPad for non-funclet EH");
1521 
1522  llvm::BasicBlock *&TerminateFunclet = TerminateFunclets[CurrentFuncletPad];
1523  if (TerminateFunclet)
1524  return TerminateFunclet;
1525 
1526  CGBuilderTy::InsertPoint SavedIP = Builder.saveAndClearIP();
1527 
1528  // Set up the terminate handler. This block is inserted at the very
1529  // end of the function by FinishFunction.
1530  TerminateFunclet = createBasicBlock("terminate.handler");
1531  Builder.SetInsertPoint(TerminateFunclet);
1532 
1533  // Create the cleanuppad using the current parent pad as its token. Use 'none'
1534  // if this is a top-level terminate scope, which is the common case.
1535  SaveAndRestore<llvm::Instruction *> RestoreCurrentFuncletPad(
1536  CurrentFuncletPad);
1537  llvm::Value *ParentPad = CurrentFuncletPad;
1538  if (!ParentPad)
1539  ParentPad = llvm::ConstantTokenNone::get(CGM.getLLVMContext());
1540  CurrentFuncletPad = Builder.CreateCleanupPad(ParentPad);
1541 
1542  // Emit the __std_terminate call.
1543  llvm::Value *Exn = nullptr;
1544  // In case of wasm personality, we need to pass the exception value to
1545  // __clang_call_terminate function.
1546  if (getLangOpts().CPlusPlus &&
1548  llvm::Value *GetExnFn =
1549  CGM.getIntrinsic(llvm::Intrinsic::wasm_get_exception);
1550  Exn = Builder.CreateCall(GetExnFn, CurrentFuncletPad);
1551  }
1552  llvm::CallInst *terminateCall =
1553  CGM.getCXXABI().emitTerminateForUnexpectedException(*this, Exn);
1554  terminateCall->setDoesNotReturn();
1555  Builder.CreateUnreachable();
1556 
1557  // Restore the saved insertion state.
1558  Builder.restoreIP(SavedIP);
1559 
1560  return TerminateFunclet;
1561 }
1562 
1563 llvm::BasicBlock *CodeGenFunction::getEHResumeBlock(bool isCleanup) {
1564  if (EHResumeBlock) return EHResumeBlock;
1565 
1566  CGBuilderTy::InsertPoint SavedIP = Builder.saveIP();
1567 
1568  // We emit a jump to a notional label at the outermost unwind state.
1569  EHResumeBlock = createBasicBlock("eh.resume");
1570  Builder.SetInsertPoint(EHResumeBlock);
1571 
1572  const EHPersonality &Personality = EHPersonality::get(*this);
1573 
1574  // This can always be a call because we necessarily didn't find
1575  // anything on the EH stack which needs our help.
1576  const char *RethrowName = Personality.CatchallRethrowFn;
1577  if (RethrowName != nullptr && !isCleanup) {
1578  EmitRuntimeCall(getCatchallRethrowFn(CGM, RethrowName),
1579  getExceptionFromSlot())->setDoesNotReturn();
1580  Builder.CreateUnreachable();
1581  Builder.restoreIP(SavedIP);
1582  return EHResumeBlock;
1583  }
1584 
1585  // Recreate the landingpad's return value for the 'resume' instruction.
1586  llvm::Value *Exn = getExceptionFromSlot();
1587  llvm::Value *Sel = getSelectorFromSlot();
1588 
1589  llvm::Type *LPadType = llvm::StructType::get(Exn->getType(), Sel->getType());
1590  llvm::Value *LPadVal = llvm::UndefValue::get(LPadType);
1591  LPadVal = Builder.CreateInsertValue(LPadVal, Exn, 0, "lpad.val");
1592  LPadVal = Builder.CreateInsertValue(LPadVal, Sel, 1, "lpad.val");
1593 
1594  Builder.CreateResume(LPadVal);
1595  Builder.restoreIP(SavedIP);
1596  return EHResumeBlock;
1597 }
1598 
1600  EnterSEHTryStmt(S);
1601  {
1602  JumpDest TryExit = getJumpDestInCurrentScope("__try.__leave");
1603 
1604  SEHTryEpilogueStack.push_back(&TryExit);
1605  EmitStmt(S.getTryBlock());
1606  SEHTryEpilogueStack.pop_back();
1607 
1608  if (!TryExit.getBlock()->use_empty())
1609  EmitBlock(TryExit.getBlock(), /*IsFinished=*/true);
1610  else
1611  delete TryExit.getBlock();
1612  }
1613  ExitSEHTryStmt(S);
1614 }
1615 
1616 namespace {
1617 struct PerformSEHFinally final : EHScopeStack::Cleanup {
1618  llvm::Function *OutlinedFinally;
1619  PerformSEHFinally(llvm::Function *OutlinedFinally)
1620  : OutlinedFinally(OutlinedFinally) {}
1621 
1622  void Emit(CodeGenFunction &CGF, Flags F) override {
1623  ASTContext &Context = CGF.getContext();
1624  CodeGenModule &CGM = CGF.CGM;
1625 
1626  CallArgList Args;
1627 
1628  // Compute the two argument values.
1629  QualType ArgTys[2] = {Context.UnsignedCharTy, Context.VoidPtrTy};
1630  llvm::Value *LocalAddrFn = CGM.getIntrinsic(llvm::Intrinsic::localaddress);
1631  llvm::Value *FP = CGF.Builder.CreateCall(LocalAddrFn);
1632  llvm::Value *IsForEH =
1633  llvm::ConstantInt::get(CGF.ConvertType(ArgTys[0]), F.isForEHCleanup());
1634  Args.add(RValue::get(IsForEH), ArgTys[0]);
1635  Args.add(RValue::get(FP), ArgTys[1]);
1636 
1637  // Arrange a two-arg function info and type.
1638  const CGFunctionInfo &FnInfo =
1639  CGM.getTypes().arrangeBuiltinFunctionCall(Context.VoidTy, Args);
1640 
1641  auto Callee = CGCallee::forDirect(OutlinedFinally);
1642  CGF.EmitCall(FnInfo, Callee, ReturnValueSlot(), Args);
1643  }
1644 };
1645 } // end anonymous namespace
1646 
1647 namespace {
1648 /// Find all local variable captures in the statement.
1649 struct CaptureFinder : ConstStmtVisitor<CaptureFinder> {
1650  CodeGenFunction &ParentCGF;
1651  const VarDecl *ParentThis;
1653  Address SEHCodeSlot = Address::invalid();
1654  CaptureFinder(CodeGenFunction &ParentCGF, const VarDecl *ParentThis)
1655  : ParentCGF(ParentCGF), ParentThis(ParentThis) {}
1656 
1657  // Return true if we need to do any capturing work.
1658  bool foundCaptures() {
1659  return !Captures.empty() || SEHCodeSlot.isValid();
1660  }
1661 
1662  void Visit(const Stmt *S) {
1663  // See if this is a capture, then recurse.
1665  for (const Stmt *Child : S->children())
1666  if (Child)
1667  Visit(Child);
1668  }
1669 
1670  void VisitDeclRefExpr(const DeclRefExpr *E) {
1671  // If this is already a capture, just make sure we capture 'this'.
1673  Captures.insert(ParentThis);
1674  return;
1675  }
1676 
1677  const auto *D = dyn_cast<VarDecl>(E->getDecl());
1678  if (D && D->isLocalVarDeclOrParm() && D->hasLocalStorage())
1679  Captures.insert(D);
1680  }
1681 
1682  void VisitCXXThisExpr(const CXXThisExpr *E) {
1683  Captures.insert(ParentThis);
1684  }
1685 
1686  void VisitCallExpr(const CallExpr *E) {
1687  // We only need to add parent frame allocations for these builtins in x86.
1688  if (ParentCGF.getTarget().getTriple().getArch() != llvm::Triple::x86)
1689  return;
1690 
1691  unsigned ID = E->getBuiltinCallee();
1692  switch (ID) {
1693  case Builtin::BI__exception_code:
1694  case Builtin::BI_exception_code:
1695  // This is the simple case where we are the outermost finally. All we
1696  // have to do here is make sure we escape this and recover it in the
1697  // outlined handler.
1698  if (!SEHCodeSlot.isValid())
1699  SEHCodeSlot = ParentCGF.SEHCodeSlotStack.back();
1700  break;
1701  }
1702  }
1703 };
1704 } // end anonymous namespace
1705 
1707  Address ParentVar,
1708  llvm::Value *ParentFP) {
1709  llvm::CallInst *RecoverCall = nullptr;
1710  CGBuilderTy Builder(*this, AllocaInsertPt);
1711  if (auto *ParentAlloca = dyn_cast<llvm::AllocaInst>(ParentVar.getPointer())) {
1712  // Mark the variable escaped if nobody else referenced it and compute the
1713  // localescape index.
1714  auto InsertPair = ParentCGF.EscapedLocals.insert(
1715  std::make_pair(ParentAlloca, ParentCGF.EscapedLocals.size()));
1716  int FrameEscapeIdx = InsertPair.first->second;
1717  // call i8* @llvm.localrecover(i8* bitcast(@parentFn), i8* %fp, i32 N)
1718  llvm::Function *FrameRecoverFn = llvm::Intrinsic::getDeclaration(
1719  &CGM.getModule(), llvm::Intrinsic::localrecover);
1720  llvm::Constant *ParentI8Fn =
1721  llvm::ConstantExpr::getBitCast(ParentCGF.CurFn, Int8PtrTy);
1722  RecoverCall = Builder.CreateCall(
1723  FrameRecoverFn, {ParentI8Fn, ParentFP,
1724  llvm::ConstantInt::get(Int32Ty, FrameEscapeIdx)});
1725 
1726  } else {
1727  // If the parent didn't have an alloca, we're doing some nested outlining.
1728  // Just clone the existing localrecover call, but tweak the FP argument to
1729  // use our FP value. All other arguments are constants.
1730  auto *ParentRecover =
1731  cast<llvm::IntrinsicInst>(ParentVar.getPointer()->stripPointerCasts());
1732  assert(ParentRecover->getIntrinsicID() == llvm::Intrinsic::localrecover &&
1733  "expected alloca or localrecover in parent LocalDeclMap");
1734  RecoverCall = cast<llvm::CallInst>(ParentRecover->clone());
1735  RecoverCall->setArgOperand(1, ParentFP);
1736  RecoverCall->insertBefore(AllocaInsertPt);
1737  }
1738 
1739  // Bitcast the variable, rename it, and insert it in the local decl map.
1740  llvm::Value *ChildVar =
1741  Builder.CreateBitCast(RecoverCall, ParentVar.getType());
1742  ChildVar->setName(ParentVar.getName());
1743  return Address(ChildVar, ParentVar.getAlignment());
1744 }
1745 
1747  const Stmt *OutlinedStmt,
1748  bool IsFilter) {
1749  // Find all captures in the Stmt.
1750  CaptureFinder Finder(ParentCGF, ParentCGF.CXXABIThisDecl);
1751  Finder.Visit(OutlinedStmt);
1752 
1753  // We can exit early on x86_64 when there are no captures. We just have to
1754  // save the exception code in filters so that __exception_code() works.
1755  if (!Finder.foundCaptures() &&
1756  CGM.getTarget().getTriple().getArch() != llvm::Triple::x86) {
1757  if (IsFilter)
1758  EmitSEHExceptionCodeSave(ParentCGF, nullptr, nullptr);
1759  return;
1760  }
1761 
1762  llvm::Value *EntryFP = nullptr;
1763  CGBuilderTy Builder(CGM, AllocaInsertPt);
1764  if (IsFilter && CGM.getTarget().getTriple().getArch() == llvm::Triple::x86) {
1765  // 32-bit SEH filters need to be careful about FP recovery. The end of the
1766  // EH registration is passed in as the EBP physical register. We can
1767  // recover that with llvm.frameaddress(1).
1768  EntryFP = Builder.CreateCall(
1769  CGM.getIntrinsic(llvm::Intrinsic::frameaddress), {Builder.getInt32(1)});
1770  } else {
1771  // Otherwise, for x64 and 32-bit finally functions, the parent FP is the
1772  // second parameter.
1773  auto AI = CurFn->arg_begin();
1774  ++AI;
1775  EntryFP = &*AI;
1776  }
1777 
1778  llvm::Value *ParentFP = EntryFP;
1779  if (IsFilter) {
1780  // Given whatever FP the runtime provided us in EntryFP, recover the true
1781  // frame pointer of the parent function. We only need to do this in filters,
1782  // since finally funclets recover the parent FP for us.
1783  llvm::Function *RecoverFPIntrin =
1784  CGM.getIntrinsic(llvm::Intrinsic::x86_seh_recoverfp);
1785  llvm::Constant *ParentI8Fn =
1786  llvm::ConstantExpr::getBitCast(ParentCGF.CurFn, Int8PtrTy);
1787  ParentFP = Builder.CreateCall(RecoverFPIntrin, {ParentI8Fn, EntryFP});
1788  }
1789 
1790  // Create llvm.localrecover calls for all captures.
1791  for (const VarDecl *VD : Finder.Captures) {
1792  if (isa<ImplicitParamDecl>(VD)) {
1793  CGM.ErrorUnsupported(VD, "'this' captured by SEH");
1794  CXXThisValue = llvm::UndefValue::get(ConvertTypeForMem(VD->getType()));
1795  continue;
1796  }
1797  if (VD->getType()->isVariablyModifiedType()) {
1798  CGM.ErrorUnsupported(VD, "VLA captured by SEH");
1799  continue;
1800  }
1801  assert((isa<ImplicitParamDecl>(VD) || VD->isLocalVarDeclOrParm()) &&
1802  "captured non-local variable");
1803 
1804  // If this decl hasn't been declared yet, it will be declared in the
1805  // OutlinedStmt.
1806  auto I = ParentCGF.LocalDeclMap.find(VD);
1807  if (I == ParentCGF.LocalDeclMap.end())
1808  continue;
1809 
1810  Address ParentVar = I->second;
1811  setAddrOfLocalVar(
1812  VD, recoverAddrOfEscapedLocal(ParentCGF, ParentVar, ParentFP));
1813  }
1814 
1815  if (Finder.SEHCodeSlot.isValid()) {
1816  SEHCodeSlotStack.push_back(
1817  recoverAddrOfEscapedLocal(ParentCGF, Finder.SEHCodeSlot, ParentFP));
1818  }
1819 
1820  if (IsFilter)
1821  EmitSEHExceptionCodeSave(ParentCGF, ParentFP, EntryFP);
1822 }
1823 
1824 /// Arrange a function prototype that can be called by Windows exception
1825 /// handling personalities. On Win64, the prototype looks like:
1826 /// RetTy func(void *EHPtrs, void *ParentFP);
1828  bool IsFilter,
1829  const Stmt *OutlinedStmt) {
1830  SourceLocation StartLoc = OutlinedStmt->getBeginLoc();
1831 
1832  // Get the mangled function name.
1833  SmallString<128> Name;
1834  {
1835  llvm::raw_svector_ostream OS(Name);
1836  const NamedDecl *ParentSEHFn = ParentCGF.CurSEHParent;
1837  assert(ParentSEHFn && "No CurSEHParent!");
1838  MangleContext &Mangler = CGM.getCXXABI().getMangleContext();
1839  if (IsFilter)
1840  Mangler.mangleSEHFilterExpression(ParentSEHFn, OS);
1841  else
1842  Mangler.mangleSEHFinallyBlock(ParentSEHFn, OS);
1843  }
1844 
1845  FunctionArgList Args;
1846  if (CGM.getTarget().getTriple().getArch() != llvm::Triple::x86 || !IsFilter) {
1847  // All SEH finally functions take two parameters. Win64 filters take two
1848  // parameters. Win32 filters take no parameters.
1849  if (IsFilter) {
1850  Args.push_back(ImplicitParamDecl::Create(
1851  getContext(), /*DC=*/nullptr, StartLoc,
1852  &getContext().Idents.get("exception_pointers"),
1854  } else {
1855  Args.push_back(ImplicitParamDecl::Create(
1856  getContext(), /*DC=*/nullptr, StartLoc,
1857  &getContext().Idents.get("abnormal_termination"),
1859  }
1860  Args.push_back(ImplicitParamDecl::Create(
1861  getContext(), /*DC=*/nullptr, StartLoc,
1862  &getContext().Idents.get("frame_pointer"), getContext().VoidPtrTy,
1864  }
1865 
1866  QualType RetTy = IsFilter ? getContext().LongTy : getContext().VoidTy;
1867 
1868  const CGFunctionInfo &FnInfo =
1869  CGM.getTypes().arrangeBuiltinFunctionDeclaration(RetTy, Args);
1870 
1871  llvm::FunctionType *FnTy = CGM.getTypes().GetFunctionType(FnInfo);
1872  llvm::Function *Fn = llvm::Function::Create(
1873  FnTy, llvm::GlobalValue::InternalLinkage, Name.str(), &CGM.getModule());
1874 
1875  IsOutlinedSEHHelper = true;
1876 
1877  StartFunction(GlobalDecl(), RetTy, Fn, FnInfo, Args,
1878  OutlinedStmt->getBeginLoc(), OutlinedStmt->getBeginLoc());
1879  CurSEHParent = ParentCGF.CurSEHParent;
1880 
1881  CGM.SetLLVMFunctionAttributes(GlobalDecl(), FnInfo, CurFn);
1882  EmitCapturedLocals(ParentCGF, OutlinedStmt, IsFilter);
1883 }
1884 
1885 /// Create a stub filter function that will ultimately hold the code of the
1886 /// filter expression. The EH preparation passes in LLVM will outline the code
1887 /// from the main function body into this stub.
1888 llvm::Function *
1890  const SEHExceptStmt &Except) {
1891  const Expr *FilterExpr = Except.getFilterExpr();
1892  startOutlinedSEHHelper(ParentCGF, true, FilterExpr);
1893 
1894  // Emit the original filter expression, convert to i32, and return.
1895  llvm::Value *R = EmitScalarExpr(FilterExpr);
1896  R = Builder.CreateIntCast(R, ConvertType(getContext().LongTy),
1897  FilterExpr->getType()->isSignedIntegerType());
1898  Builder.CreateStore(R, ReturnValue);
1899 
1900  FinishFunction(FilterExpr->getEndLoc());
1901 
1902  return CurFn;
1903 }
1904 
1905 llvm::Function *
1907  const SEHFinallyStmt &Finally) {
1908  const Stmt *FinallyBlock = Finally.getBlock();
1909  startOutlinedSEHHelper(ParentCGF, false, FinallyBlock);
1910 
1911  // Emit the original filter expression, convert to i32, and return.
1912  EmitStmt(FinallyBlock);
1913 
1914  FinishFunction(FinallyBlock->getEndLoc());
1915 
1916  return CurFn;
1917 }
1918 
1920  llvm::Value *ParentFP,
1921  llvm::Value *EntryFP) {
1922  // Get the pointer to the EXCEPTION_POINTERS struct. This is returned by the
1923  // __exception_info intrinsic.
1924  if (CGM.getTarget().getTriple().getArch() != llvm::Triple::x86) {
1925  // On Win64, the info is passed as the first parameter to the filter.
1926  SEHInfo = &*CurFn->arg_begin();
1927  SEHCodeSlotStack.push_back(
1928  CreateMemTemp(getContext().IntTy, "__exception_code"));
1929  } else {
1930  // On Win32, the EBP on entry to the filter points to the end of an
1931  // exception registration object. It contains 6 32-bit fields, and the info
1932  // pointer is stored in the second field. So, GEP 20 bytes backwards and
1933  // load the pointer.
1934  SEHInfo = Builder.CreateConstInBoundsGEP1_32(Int8Ty, EntryFP, -20);
1935  SEHInfo = Builder.CreateBitCast(SEHInfo, Int8PtrTy->getPointerTo());
1936  SEHInfo = Builder.CreateAlignedLoad(Int8PtrTy, SEHInfo, getPointerAlign());
1937  SEHCodeSlotStack.push_back(recoverAddrOfEscapedLocal(
1938  ParentCGF, ParentCGF.SEHCodeSlotStack.back(), ParentFP));
1939  }
1940 
1941  // Save the exception code in the exception slot to unify exception access in
1942  // the filter function and the landing pad.
1943  // struct EXCEPTION_POINTERS {
1944  // EXCEPTION_RECORD *ExceptionRecord;
1945  // CONTEXT *ContextRecord;
1946  // };
1947  // int exceptioncode = exception_pointers->ExceptionRecord->ExceptionCode;
1948  llvm::Type *RecordTy = CGM.Int32Ty->getPointerTo();
1949  llvm::Type *PtrsTy = llvm::StructType::get(RecordTy, CGM.VoidPtrTy);
1950  llvm::Value *Ptrs = Builder.CreateBitCast(SEHInfo, PtrsTy->getPointerTo());
1951  llvm::Value *Rec = Builder.CreateStructGEP(PtrsTy, Ptrs, 0);
1952  Rec = Builder.CreateAlignedLoad(Rec, getPointerAlign());
1953  llvm::Value *Code = Builder.CreateAlignedLoad(Rec, getIntAlign());
1954  assert(!SEHCodeSlotStack.empty() && "emitting EH code outside of __except");
1955  Builder.CreateStore(Code, SEHCodeSlotStack.back());
1956 }
1957 
1959  // Sema should diagnose calling this builtin outside of a filter context, but
1960  // don't crash if we screw up.
1961  if (!SEHInfo)
1962  return llvm::UndefValue::get(Int8PtrTy);
1963  assert(SEHInfo->getType() == Int8PtrTy);
1964  return SEHInfo;
1965 }
1966 
1968  assert(!SEHCodeSlotStack.empty() && "emitting EH code outside of __except");
1969  return Builder.CreateLoad(SEHCodeSlotStack.back());
1970 }
1971 
1973  // Abnormal termination is just the first parameter to the outlined finally
1974  // helper.
1975  auto AI = CurFn->arg_begin();
1976  return Builder.CreateZExt(&*AI, Int32Ty);
1977 }
1978 
1980  llvm::Function *FinallyFunc) {
1981  EHStack.pushCleanup<PerformSEHFinally>(Kind, FinallyFunc);
1982 }
1983 
1985  CodeGenFunction HelperCGF(CGM, /*suppressNewContext=*/true);
1986  if (const SEHFinallyStmt *Finally = S.getFinallyHandler()) {
1987  // Outline the finally block.
1988  llvm::Function *FinallyFunc =
1989  HelperCGF.GenerateSEHFinallyFunction(*this, *Finally);
1990 
1991  // Push a cleanup for __finally blocks.
1992  EHStack.pushCleanup<PerformSEHFinally>(NormalAndEHCleanup, FinallyFunc);
1993  return;
1994  }
1995 
1996  // Otherwise, we must have an __except block.
1997  const SEHExceptStmt *Except = S.getExceptHandler();
1998  assert(Except);
1999  EHCatchScope *CatchScope = EHStack.pushCatch(1);
2000  SEHCodeSlotStack.push_back(
2001  CreateMemTemp(getContext().IntTy, "__exception_code"));
2002 
2003  // If the filter is known to evaluate to 1, then we can use the clause
2004  // "catch i8* null". We can't do this on x86 because the filter has to save
2005  // the exception code.
2006  llvm::Constant *C =
2008  getContext().IntTy);
2009  if (CGM.getTarget().getTriple().getArch() != llvm::Triple::x86 && C &&
2010  C->isOneValue()) {
2011  CatchScope->setCatchAllHandler(0, createBasicBlock("__except"));
2012  return;
2013  }
2014 
2015  // In general, we have to emit an outlined filter function. Use the function
2016  // in place of the RTTI typeinfo global that C++ EH uses.
2017  llvm::Function *FilterFunc =
2018  HelperCGF.GenerateSEHFilterFunction(*this, *Except);
2019  llvm::Constant *OpaqueFunc =
2020  llvm::ConstantExpr::getBitCast(FilterFunc, Int8PtrTy);
2021  CatchScope->setHandler(0, OpaqueFunc, createBasicBlock("__except.ret"));
2022 }
2023 
2025  // Just pop the cleanup if it's a __finally block.
2026  if (S.getFinallyHandler()) {
2027  PopCleanupBlock();
2028  return;
2029  }
2030 
2031  // Otherwise, we must have an __except block.
2032  const SEHExceptStmt *Except = S.getExceptHandler();
2033  assert(Except && "__try must have __finally xor __except");
2034  EHCatchScope &CatchScope = cast<EHCatchScope>(*EHStack.begin());
2035 
2036  // Don't emit the __except block if the __try block lacked invokes.
2037  // TODO: Model unwind edges from instructions, either with iload / istore or
2038  // a try body function.
2039  if (!CatchScope.hasEHBranches()) {
2040  CatchScope.clearHandlerBlocks();
2041  EHStack.popCatch();
2042  SEHCodeSlotStack.pop_back();
2043  return;
2044  }
2045 
2046  // The fall-through block.
2047  llvm::BasicBlock *ContBB = createBasicBlock("__try.cont");
2048 
2049  // We just emitted the body of the __try; jump to the continue block.
2050  if (HaveInsertPoint())
2051  Builder.CreateBr(ContBB);
2052 
2053  // Check if our filter function returned true.
2054  emitCatchDispatchBlock(*this, CatchScope);
2055 
2056  // Grab the block before we pop the handler.
2057  llvm::BasicBlock *CatchPadBB = CatchScope.getHandler(0).Block;
2058  EHStack.popCatch();
2059 
2060  EmitBlockAfterUses(CatchPadBB);
2061 
2062  // __except blocks don't get outlined into funclets, so immediately do a
2063  // catchret.
2064  llvm::CatchPadInst *CPI =
2065  cast<llvm::CatchPadInst>(CatchPadBB->getFirstNonPHI());
2066  llvm::BasicBlock *ExceptBB = createBasicBlock("__except");
2067  Builder.CreateCatchRet(CPI, ExceptBB);
2068  EmitBlock(ExceptBB);
2069 
2070  // On Win64, the exception code is returned in EAX. Copy it into the slot.
2071  if (CGM.getTarget().getTriple().getArch() != llvm::Triple::x86) {
2072  llvm::Function *SEHCodeIntrin =
2073  CGM.getIntrinsic(llvm::Intrinsic::eh_exceptioncode);
2074  llvm::Value *Code = Builder.CreateCall(SEHCodeIntrin, {CPI});
2075  Builder.CreateStore(Code, SEHCodeSlotStack.back());
2076  }
2077 
2078  // Emit the __except body.
2079  EmitStmt(Except->getBlock());
2080 
2081  // End the lifetime of the exception code.
2082  SEHCodeSlotStack.pop_back();
2083 
2084  if (HaveInsertPoint())
2085  Builder.CreateBr(ContBB);
2086 
2087  EmitBlock(ContBB);
2088 }
2089 
2091  // If this code is reachable then emit a stop point (if generating
2092  // debug info). We have to do this ourselves because we are on the
2093  // "simple" statement path.
2094  if (HaveInsertPoint())
2095  EmitStopPoint(&S);
2096 
2097  // This must be a __leave from a __finally block, which we warn on and is UB.
2098  // Just emit unreachable.
2099  if (!isSEHTryScope()) {
2100  Builder.CreateUnreachable();
2101  Builder.ClearInsertionPoint();
2102  return;
2103  }
2104 
2105  EmitBranchThroughCleanup(*SEHTryEpilogueStack.back());
2106 }
virtual void mangleSEHFilterExpression(const NamedDecl *EnclosingDecl, raw_ostream &Out)=0
const llvm::DataLayout & getDataLayout() const
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:1739
llvm::IntegerType * IntTy
int
EHScopeStack::stable_iterator getEnclosingEHScope() const
Definition: CGCleanup.h:138
Other implicit parameter.
Definition: Decl.h:1511
CompoundStmt * getBlock() const
Definition: Stmt.h:2790
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:1043
A (possibly-)qualified type.
Definition: Type.h:642
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
Return the number of types in the exception specification.
Definition: Type.h:3939
const Expr * getSubExpr() const
Definition: ExprCXX.h:1032
ConstStmtVisitor - This class implements a simple visitor for Stmt subclasses.
Definition: StmtVisitor.h:193
llvm::BasicBlock * getCachedEHDispatchBlock() const
Definition: CGCleanup.h:124
bool HaveInsertPoint() const
HaveInsertPoint - True if an insertion point is defined.
llvm::LLVMContext & getLLVMContext()
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:104
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:2228
bool hasEHBranches() const
Definition: CGCleanup.h:132
Decl - This represents one declaration (or definition), e.g.
Definition: DeclBase.h:87
Stmt * getHandlerBlock() const
Definition: StmtCXX.h:52
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:6231
Represents Objective-C&#39;s @throw statement.
Definition: StmtObjC.h:313
CanQualType LongTy
Definition: ASTContext.h:1024
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:2115
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:3795
Represents a variable declaration or definition.
Definition: Decl.h:812
const T * getAs() const
Member-template getAs<specific type>&#39;.
Definition: Type.h:6716
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:1010
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:141
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:154
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:288
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
Return the ith exception type, where 0 <= i < getNumExceptions().
Definition: Type.h:3947
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:237
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:4053
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:1025
Represents the this expression in C++.
Definition: ExprCXX.h:971
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:4418
&#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:3686
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.
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:50
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:65
bool refersToEnclosingVariableOrCapture() const
Does this DeclRefExpr refer to an enclosing local or a captured variable?
Definition: Expr.h:1250
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:644
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:1844
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:295
clang::ObjCRuntime ObjCRuntime
Definition: LangOptions.h:199
static const EHPersonality GNU_ObjC_SEH
Definition: CGCleanup.h:620
const TargetInfo & getTarget() const
ValueDecl * getDecl()
Definition: Expr.h:1125
&#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:301
unsigned getBuiltinCallee() const
getBuiltinCallee - If this is a call to a builtin, return the builtin ID of the callee.
Definition: Expr.cpp:1317
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
llvm::cl::opt< std::string > Filter
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:103
bool isVariablyModifiedType() const
Whether this type is a variably-modified type (C99 6.7.5).
Definition: Type.h:2101
&#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:3754
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:46
CanQualType VoidTy
Definition: ASTContext.h:1015
bool isObjCObjectPointerType() const
Definition: Type.h:6379
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:3913
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:722
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:1113
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:2850
&#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:2976
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:443
void EnterCXXTryStmt(const CXXTryStmt &S, bool IsFnTryBlock=false)
SEHFinallyStmt * getFinallyHandler() const
Definition: Stmt.cpp:1117
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:6138
Expr * getFilterExpr() const
Definition: Stmt.h:2753
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:6085
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:96
llvm::Value * EmitSEHAbnormalTermination()
CallExpr - Represents a function call (C99 6.5.2.2, C++ [expr.call]).
Definition: Expr.h:2407
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:1024
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:1042
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:647
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:480
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:2830
CompoundStmt * getBlock() const
Definition: Stmt.h:2757
void EmitCXXThrowExpr(const CXXThrowExpr *E, bool KeepInsertionPoint=true)
bool isLocalVarDeclOrParm() const
Similar to isLocalVarDecl but also includes parameters.
Definition: Decl.h:1113
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)