clang  10.0.0git
CGException.cpp
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1 //===--- CGException.cpp - Emit LLVM Code for C++ exceptions ----*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This contains code dealing with C++ exception related code generation.
10 //
11 //===----------------------------------------------------------------------===//
12 
13 #include "CGCXXABI.h"
14 #include "CGCleanup.h"
15 #include "CGObjCRuntime.h"
16 #include "CodeGenFunction.h"
17 #include "ConstantEmitter.h"
18 #include "TargetInfo.h"
19 #include "clang/AST/Mangle.h"
20 #include "clang/AST/StmtCXX.h"
21 #include "clang/AST/StmtObjC.h"
22 #include "clang/AST/StmtVisitor.h"
24 #include "llvm/IR/IntrinsicInst.h"
25 #include "llvm/IR/Intrinsics.h"
26 #include "llvm/IR/IntrinsicsWebAssembly.h"
27 #include "llvm/Support/SaveAndRestore.h"
28 
29 using namespace clang;
30 using namespace CodeGen;
31 
32 static llvm::FunctionCallee getFreeExceptionFn(CodeGenModule &CGM) {
33  // void __cxa_free_exception(void *thrown_exception);
34 
35  llvm::FunctionType *FTy =
36  llvm::FunctionType::get(CGM.VoidTy, CGM.Int8PtrTy, /*isVarArg=*/false);
37 
38  return CGM.CreateRuntimeFunction(FTy, "__cxa_free_exception");
39 }
40 
41 static llvm::FunctionCallee getUnexpectedFn(CodeGenModule &CGM) {
42  // void __cxa_call_unexpected(void *thrown_exception);
43 
44  llvm::FunctionType *FTy =
45  llvm::FunctionType::get(CGM.VoidTy, CGM.Int8PtrTy, /*isVarArg=*/false);
46 
47  return CGM.CreateRuntimeFunction(FTy, "__cxa_call_unexpected");
48 }
49 
50 llvm::FunctionCallee CodeGenModule::getTerminateFn() {
51  // void __terminate();
52 
53  llvm::FunctionType *FTy =
54  llvm::FunctionType::get(VoidTy, /*isVarArg=*/false);
55 
56  StringRef name;
57 
58  // In C++, use std::terminate().
59  if (getLangOpts().CPlusPlus &&
60  getTarget().getCXXABI().isItaniumFamily()) {
61  name = "_ZSt9terminatev";
62  } else if (getLangOpts().CPlusPlus &&
63  getTarget().getCXXABI().isMicrosoft()) {
64  if (getLangOpts().isCompatibleWithMSVC(LangOptions::MSVC2015))
65  name = "__std_terminate";
66  else
67  name = "?terminate@@YAXXZ";
68  } else if (getLangOpts().ObjC &&
70  name = "objc_terminate";
71  else
72  name = "abort";
73  return CreateRuntimeFunction(FTy, name);
74 }
75 
76 static llvm::FunctionCallee getCatchallRethrowFn(CodeGenModule &CGM,
77  StringRef Name) {
78  llvm::FunctionType *FTy =
79  llvm::FunctionType::get(CGM.VoidTy, CGM.Int8PtrTy, /*isVarArg=*/false);
80 
81  return CGM.CreateRuntimeFunction(FTy, Name);
82 }
83 
84 const EHPersonality EHPersonality::GNU_C = { "__gcc_personality_v0", nullptr };
85 const EHPersonality
86 EHPersonality::GNU_C_SJLJ = { "__gcc_personality_sj0", nullptr };
87 const EHPersonality
88 EHPersonality::GNU_C_SEH = { "__gcc_personality_seh0", nullptr };
89 const EHPersonality
90 EHPersonality::NeXT_ObjC = { "__objc_personality_v0", nullptr };
91 const EHPersonality
92 EHPersonality::GNU_CPlusPlus = { "__gxx_personality_v0", nullptr };
93 const EHPersonality
94 EHPersonality::GNU_CPlusPlus_SJLJ = { "__gxx_personality_sj0", nullptr };
95 const EHPersonality
96 EHPersonality::GNU_CPlusPlus_SEH = { "__gxx_personality_seh0", nullptr };
97 const EHPersonality
98 EHPersonality::GNU_ObjC = {"__gnu_objc_personality_v0", "objc_exception_throw"};
99 const EHPersonality
100 EHPersonality::GNU_ObjC_SJLJ = {"__gnu_objc_personality_sj0", "objc_exception_throw"};
101 const EHPersonality
102 EHPersonality::GNU_ObjC_SEH = {"__gnu_objc_personality_seh0", "objc_exception_throw"};
103 const EHPersonality
104 EHPersonality::GNU_ObjCXX = { "__gnustep_objcxx_personality_v0", nullptr };
105 const EHPersonality
106 EHPersonality::GNUstep_ObjC = { "__gnustep_objc_personality_v0", nullptr };
107 const EHPersonality
108 EHPersonality::MSVC_except_handler = { "_except_handler3", nullptr };
109 const EHPersonality
110 EHPersonality::MSVC_C_specific_handler = { "__C_specific_handler", nullptr };
111 const EHPersonality
112 EHPersonality::MSVC_CxxFrameHandler3 = { "__CxxFrameHandler3", nullptr };
113 const EHPersonality
114 EHPersonality::GNU_Wasm_CPlusPlus = { "__gxx_wasm_personality_v0", nullptr };
115 
116 static const EHPersonality &getCPersonality(const TargetInfo &Target,
117  const LangOptions &L) {
118  const llvm::Triple &T = Target.getTriple();
119  if (T.isWindowsMSVCEnvironment())
120  return EHPersonality::MSVC_CxxFrameHandler3;
121  if (L.SjLjExceptions)
123  if (L.DWARFExceptions)
124  return EHPersonality::GNU_C;
125  if (L.SEHExceptions)
127  return EHPersonality::GNU_C;
128 }
129 
130 static const EHPersonality &getObjCPersonality(const TargetInfo &Target,
131  const LangOptions &L) {
132  const llvm::Triple &T = Target.getTriple();
133  if (T.isWindowsMSVCEnvironment())
134  return EHPersonality::MSVC_CxxFrameHandler3;
135 
136  switch (L.ObjCRuntime.getKind()) {
138  return getCPersonality(Target, L);
139  case ObjCRuntime::MacOSX:
140  case ObjCRuntime::iOS:
144  if (L.ObjCRuntime.getVersion() >= VersionTuple(1, 7))
145  return EHPersonality::GNUstep_ObjC;
146  LLVM_FALLTHROUGH;
147  case ObjCRuntime::GCC:
148  case ObjCRuntime::ObjFW:
149  if (L.SjLjExceptions)
151  if (L.SEHExceptions)
154  }
155  llvm_unreachable("bad runtime kind");
156 }
157 
158 static const EHPersonality &getCXXPersonality(const TargetInfo &Target,
159  const LangOptions &L) {
160  const llvm::Triple &T = Target.getTriple();
161  if (T.isWindowsMSVCEnvironment())
162  return EHPersonality::MSVC_CxxFrameHandler3;
163  if (L.SjLjExceptions)
165  if (L.DWARFExceptions)
167  if (L.SEHExceptions)
169  if (L.WasmExceptions)
172 }
173 
174 /// Determines the personality function to use when both C++
175 /// and Objective-C exceptions are being caught.
176 static const EHPersonality &getObjCXXPersonality(const TargetInfo &Target,
177  const LangOptions &L) {
178  if (Target.getTriple().isWindowsMSVCEnvironment())
179  return EHPersonality::MSVC_CxxFrameHandler3;
180 
181  switch (L.ObjCRuntime.getKind()) {
182  // In the fragile ABI, just use C++ exception handling and hope
183  // they're not doing crazy exception mixing.
185  return getCXXPersonality(Target, L);
186 
187  // The ObjC personality defers to the C++ personality for non-ObjC
188  // handlers. Unlike the C++ case, we use the same personality
189  // function on targets using (backend-driven) SJLJ EH.
190  case ObjCRuntime::MacOSX:
191  case ObjCRuntime::iOS:
193  return getObjCPersonality(Target, L);
194 
197 
198  // The GCC runtime's personality function inherently doesn't support
199  // mixed EH. Use the ObjC personality just to avoid returning null.
200  case ObjCRuntime::GCC:
201  case ObjCRuntime::ObjFW:
202  return getObjCPersonality(Target, L);
203  }
204  llvm_unreachable("bad runtime kind");
205 }
206 
207 static const EHPersonality &getSEHPersonalityMSVC(const llvm::Triple &T) {
208  if (T.getArch() == llvm::Triple::x86)
209  return EHPersonality::MSVC_except_handler;
211 }
212 
214  const FunctionDecl *FD) {
215  const llvm::Triple &T = CGM.getTarget().getTriple();
216  const LangOptions &L = CGM.getLangOpts();
217  const TargetInfo &Target = CGM.getTarget();
218 
219  // Functions using SEH get an SEH personality.
220  if (FD && FD->usesSEHTry())
221  return getSEHPersonalityMSVC(T);
222 
223  if (L.ObjC)
224  return L.CPlusPlus ? getObjCXXPersonality(Target, L)
225  : getObjCPersonality(Target, L);
226  return L.CPlusPlus ? getCXXPersonality(Target, L)
227  : getCPersonality(Target, L);
228 }
229 
231  const auto *FD = CGF.CurCodeDecl;
232  // For outlined finallys and filters, use the SEH personality in case they
233  // contain more SEH. This mostly only affects finallys. Filters could
234  // hypothetically use gnu statement expressions to sneak in nested SEH.
235  FD = FD ? FD : CGF.CurSEHParent;
236  return get(CGF.CGM, dyn_cast_or_null<FunctionDecl>(FD));
237 }
238 
239 static llvm::FunctionCallee getPersonalityFn(CodeGenModule &CGM,
240  const EHPersonality &Personality) {
241  return CGM.CreateRuntimeFunction(llvm::FunctionType::get(CGM.Int32Ty, true),
242  Personality.PersonalityFn,
243  llvm::AttributeList(), /*Local=*/true);
244 }
245 
246 static llvm::Constant *getOpaquePersonalityFn(CodeGenModule &CGM,
247  const EHPersonality &Personality) {
248  llvm::FunctionCallee Fn = getPersonalityFn(CGM, Personality);
249  llvm::PointerType* Int8PtrTy = llvm::PointerType::get(
250  llvm::Type::getInt8Ty(CGM.getLLVMContext()),
251  CGM.getDataLayout().getProgramAddressSpace());
252 
253  return llvm::ConstantExpr::getBitCast(cast<llvm::Constant>(Fn.getCallee()),
254  Int8PtrTy);
255 }
256 
257 /// Check whether a landingpad instruction only uses C++ features.
258 static bool LandingPadHasOnlyCXXUses(llvm::LandingPadInst *LPI) {
259  for (unsigned I = 0, E = LPI->getNumClauses(); I != E; ++I) {
260  // Look for something that would've been returned by the ObjC
261  // runtime's GetEHType() method.
262  llvm::Value *Val = LPI->getClause(I)->stripPointerCasts();
263  if (LPI->isCatch(I)) {
264  // Check if the catch value has the ObjC prefix.
265  if (llvm::GlobalVariable *GV = dyn_cast<llvm::GlobalVariable>(Val))
266  // ObjC EH selector entries are always global variables with
267  // names starting like this.
268  if (GV->getName().startswith("OBJC_EHTYPE"))
269  return false;
270  } else {
271  // Check if any of the filter values have the ObjC prefix.
272  llvm::Constant *CVal = cast<llvm::Constant>(Val);
273  for (llvm::User::op_iterator
274  II = CVal->op_begin(), IE = CVal->op_end(); II != IE; ++II) {
275  if (llvm::GlobalVariable *GV =
276  cast<llvm::GlobalVariable>((*II)->stripPointerCasts()))
277  // ObjC EH selector entries are always global variables with
278  // names starting like this.
279  if (GV->getName().startswith("OBJC_EHTYPE"))
280  return false;
281  }
282  }
283  }
284  return true;
285 }
286 
287 /// Check whether a personality function could reasonably be swapped
288 /// for a C++ personality function.
289 static bool PersonalityHasOnlyCXXUses(llvm::Constant *Fn) {
290  for (llvm::User *U : Fn->users()) {
291  // Conditionally white-list bitcasts.
292  if (llvm::ConstantExpr *CE = dyn_cast<llvm::ConstantExpr>(U)) {
293  if (CE->getOpcode() != llvm::Instruction::BitCast) return false;
294  if (!PersonalityHasOnlyCXXUses(CE))
295  return false;
296  continue;
297  }
298 
299  // Otherwise it must be a function.
300  llvm::Function *F = dyn_cast<llvm::Function>(U);
301  if (!F) return false;
302 
303  for (auto BB = F->begin(), E = F->end(); BB != E; ++BB) {
304  if (BB->isLandingPad())
305  if (!LandingPadHasOnlyCXXUses(BB->getLandingPadInst()))
306  return false;
307  }
308  }
309 
310  return true;
311 }
312 
313 /// Try to use the C++ personality function in ObjC++. Not doing this
314 /// can cause some incompatibilities with gcc, which is more
315 /// aggressive about only using the ObjC++ personality in a function
316 /// when it really needs it.
317 void CodeGenModule::SimplifyPersonality() {
318  // If we're not in ObjC++ -fexceptions, there's nothing to do.
319  if (!LangOpts.CPlusPlus || !LangOpts.ObjC || !LangOpts.Exceptions)
320  return;
321 
322  // Both the problem this endeavors to fix and the way the logic
323  // above works is specific to the NeXT runtime.
324  if (!LangOpts.ObjCRuntime.isNeXTFamily())
325  return;
326 
327  const EHPersonality &ObjCXX = EHPersonality::get(*this, /*FD=*/nullptr);
328  const EHPersonality &CXX = getCXXPersonality(getTarget(), LangOpts);
329  if (&ObjCXX == &CXX)
330  return;
331 
332  assert(std::strcmp(ObjCXX.PersonalityFn, CXX.PersonalityFn) != 0 &&
333  "Different EHPersonalities using the same personality function.");
334 
335  llvm::Function *Fn = getModule().getFunction(ObjCXX.PersonalityFn);
336 
337  // Nothing to do if it's unused.
338  if (!Fn || Fn->use_empty()) return;
339 
340  // Can't do the optimization if it has non-C++ uses.
341  if (!PersonalityHasOnlyCXXUses(Fn)) return;
342 
343  // Create the C++ personality function and kill off the old
344  // function.
345  llvm::FunctionCallee CXXFn = getPersonalityFn(*this, CXX);
346 
347  // This can happen if the user is screwing with us.
348  if (Fn->getType() != CXXFn.getCallee()->getType())
349  return;
350 
351  Fn->replaceAllUsesWith(CXXFn.getCallee());
352  Fn->eraseFromParent();
353 }
354 
355 /// Returns the value to inject into a selector to indicate the
356 /// presence of a catch-all.
357 static llvm::Constant *getCatchAllValue(CodeGenFunction &CGF) {
358  // Possibly we should use @llvm.eh.catch.all.value here.
359  return llvm::ConstantPointerNull::get(CGF.Int8PtrTy);
360 }
361 
362 namespace {
363  /// A cleanup to free the exception object if its initialization
364  /// throws.
365  struct FreeException final : EHScopeStack::Cleanup {
366  llvm::Value *exn;
367  FreeException(llvm::Value *exn) : exn(exn) {}
368  void Emit(CodeGenFunction &CGF, Flags flags) override {
370  }
371  };
372 } // end anonymous namespace
373 
374 // Emits an exception expression into the given location. This
375 // differs from EmitAnyExprToMem only in that, if a final copy-ctor
376 // call is required, an exception within that copy ctor causes
377 // std::terminate to be invoked.
379  // Make sure the exception object is cleaned up if there's an
380  // exception during initialization.
381  pushFullExprCleanup<FreeException>(EHCleanup, addr.getPointer());
382  EHScopeStack::stable_iterator cleanup = EHStack.stable_begin();
383 
384  // __cxa_allocate_exception returns a void*; we need to cast this
385  // to the appropriate type for the object.
386  llvm::Type *ty = ConvertTypeForMem(e->getType())->getPointerTo();
387  Address typedAddr = Builder.CreateBitCast(addr, ty);
388 
389  // FIXME: this isn't quite right! If there's a final unelided call
390  // to a copy constructor, then according to [except.terminate]p1 we
391  // must call std::terminate() if that constructor throws, because
392  // technically that copy occurs after the exception expression is
393  // evaluated but before the exception is caught. But the best way
394  // to handle that is to teach EmitAggExpr to do the final copy
395  // differently if it can't be elided.
396  EmitAnyExprToMem(e, typedAddr, e->getType().getQualifiers(),
397  /*IsInit*/ true);
398 
399  // Deactivate the cleanup block.
400  DeactivateCleanupBlock(cleanup,
401  cast<llvm::Instruction>(typedAddr.getPointer()));
402 }
403 
405  if (!ExceptionSlot)
406  ExceptionSlot = CreateTempAlloca(Int8PtrTy, "exn.slot");
407  return Address(ExceptionSlot, getPointerAlign());
408 }
409 
411  if (!EHSelectorSlot)
412  EHSelectorSlot = CreateTempAlloca(Int32Ty, "ehselector.slot");
413  return Address(EHSelectorSlot, CharUnits::fromQuantity(4));
414 }
415 
417  return Builder.CreateLoad(getExceptionSlot(), "exn");
418 }
419 
421  return Builder.CreateLoad(getEHSelectorSlot(), "sel");
422 }
423 
425  bool KeepInsertionPoint) {
426  if (const Expr *SubExpr = E->getSubExpr()) {
427  QualType ThrowType = SubExpr->getType();
428  if (ThrowType->isObjCObjectPointerType()) {
429  const Stmt *ThrowStmt = E->getSubExpr();
430  const ObjCAtThrowStmt S(E->getExprLoc(), const_cast<Stmt *>(ThrowStmt));
431  CGM.getObjCRuntime().EmitThrowStmt(*this, S, false);
432  } else {
433  CGM.getCXXABI().emitThrow(*this, E);
434  }
435  } else {
436  CGM.getCXXABI().emitRethrow(*this, /*isNoReturn=*/true);
437  }
438 
439  // throw is an expression, and the expression emitters expect us
440  // to leave ourselves at a valid insertion point.
441  if (KeepInsertionPoint)
442  EmitBlock(createBasicBlock("throw.cont"));
443 }
444 
446  if (!CGM.getLangOpts().CXXExceptions)
447  return;
448 
449  const FunctionDecl* FD = dyn_cast_or_null<FunctionDecl>(D);
450  if (!FD) {
451  // Check if CapturedDecl is nothrow and create terminate scope for it.
452  if (const CapturedDecl* CD = dyn_cast_or_null<CapturedDecl>(D)) {
453  if (CD->isNothrow())
454  EHStack.pushTerminate();
455  }
456  return;
457  }
458  const FunctionProtoType *Proto = FD->getType()->getAs<FunctionProtoType>();
459  if (!Proto)
460  return;
461 
463  if (isNoexceptExceptionSpec(EST) && Proto->canThrow() == CT_Cannot) {
464  // noexcept functions are simple terminate scopes.
465  EHStack.pushTerminate();
466  } else if (EST == EST_Dynamic || EST == EST_DynamicNone) {
467  // TODO: Revisit exception specifications for the MS ABI. There is a way to
468  // encode these in an object file but MSVC doesn't do anything with it.
469  if (getTarget().getCXXABI().isMicrosoft())
470  return;
471  unsigned NumExceptions = Proto->getNumExceptions();
472  EHFilterScope *Filter = EHStack.pushFilter(NumExceptions);
473 
474  for (unsigned I = 0; I != NumExceptions; ++I) {
475  QualType Ty = Proto->getExceptionType(I);
476  QualType ExceptType = Ty.getNonReferenceType().getUnqualifiedType();
477  llvm::Value *EHType = CGM.GetAddrOfRTTIDescriptor(ExceptType,
478  /*ForEH=*/true);
479  Filter->setFilter(I, EHType);
480  }
481  }
482 }
483 
484 /// Emit the dispatch block for a filter scope if necessary.
486  EHFilterScope &filterScope) {
487  llvm::BasicBlock *dispatchBlock = filterScope.getCachedEHDispatchBlock();
488  if (!dispatchBlock) return;
489  if (dispatchBlock->use_empty()) {
490  delete dispatchBlock;
491  return;
492  }
493 
494  CGF.EmitBlockAfterUses(dispatchBlock);
495 
496  // If this isn't a catch-all filter, we need to check whether we got
497  // here because the filter triggered.
498  if (filterScope.getNumFilters()) {
499  // Load the selector value.
500  llvm::Value *selector = CGF.getSelectorFromSlot();
501  llvm::BasicBlock *unexpectedBB = CGF.createBasicBlock("ehspec.unexpected");
502 
503  llvm::Value *zero = CGF.Builder.getInt32(0);
504  llvm::Value *failsFilter =
505  CGF.Builder.CreateICmpSLT(selector, zero, "ehspec.fails");
506  CGF.Builder.CreateCondBr(failsFilter, unexpectedBB,
507  CGF.getEHResumeBlock(false));
508 
509  CGF.EmitBlock(unexpectedBB);
510  }
511 
512  // Call __cxa_call_unexpected. This doesn't need to be an invoke
513  // because __cxa_call_unexpected magically filters exceptions
514  // according to the last landing pad the exception was thrown
515  // into. Seriously.
516  llvm::Value *exn = CGF.getExceptionFromSlot();
517  CGF.EmitRuntimeCall(getUnexpectedFn(CGF.CGM), exn)
518  ->setDoesNotReturn();
519  CGF.Builder.CreateUnreachable();
520 }
521 
523  if (!CGM.getLangOpts().CXXExceptions)
524  return;
525 
526  const FunctionDecl* FD = dyn_cast_or_null<FunctionDecl>(D);
527  if (!FD) {
528  // Check if CapturedDecl is nothrow and pop terminate scope for it.
529  if (const CapturedDecl* CD = dyn_cast_or_null<CapturedDecl>(D)) {
530  if (CD->isNothrow())
531  EHStack.popTerminate();
532  }
533  return;
534  }
535  const FunctionProtoType *Proto = FD->getType()->getAs<FunctionProtoType>();
536  if (!Proto)
537  return;
538 
540  if (isNoexceptExceptionSpec(EST) && Proto->canThrow() == CT_Cannot) {
541  EHStack.popTerminate();
542  } else if (EST == EST_Dynamic || EST == EST_DynamicNone) {
543  // TODO: Revisit exception specifications for the MS ABI. There is a way to
544  // encode these in an object file but MSVC doesn't do anything with it.
545  if (getTarget().getCXXABI().isMicrosoft())
546  return;
547  EHFilterScope &filterScope = cast<EHFilterScope>(*EHStack.begin());
548  emitFilterDispatchBlock(*this, filterScope);
549  EHStack.popFilter();
550  }
551 }
552 
554  EnterCXXTryStmt(S);
555  EmitStmt(S.getTryBlock());
556  ExitCXXTryStmt(S);
557 }
558 
559 void CodeGenFunction::EnterCXXTryStmt(const CXXTryStmt &S, bool IsFnTryBlock) {
560  unsigned NumHandlers = S.getNumHandlers();
561  EHCatchScope *CatchScope = EHStack.pushCatch(NumHandlers);
562 
563  for (unsigned I = 0; I != NumHandlers; ++I) {
564  const CXXCatchStmt *C = S.getHandler(I);
565 
566  llvm::BasicBlock *Handler = createBasicBlock("catch");
567  if (C->getExceptionDecl()) {
568  // FIXME: Dropping the reference type on the type into makes it
569  // impossible to correctly implement catch-by-reference
570  // semantics for pointers. Unfortunately, this is what all
571  // existing compilers do, and it's not clear that the standard
572  // personality routine is capable of doing this right. See C++ DR 388:
573  // http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#388
574  Qualifiers CaughtTypeQuals;
575  QualType CaughtType = CGM.getContext().getUnqualifiedArrayType(
576  C->getCaughtType().getNonReferenceType(), CaughtTypeQuals);
577 
578  CatchTypeInfo TypeInfo{nullptr, 0};
579  if (CaughtType->isObjCObjectPointerType())
580  TypeInfo.RTTI = CGM.getObjCRuntime().GetEHType(CaughtType);
581  else
582  TypeInfo = CGM.getCXXABI().getAddrOfCXXCatchHandlerType(
583  CaughtType, C->getCaughtType());
584  CatchScope->setHandler(I, TypeInfo, Handler);
585  } else {
586  // No exception decl indicates '...', a catch-all.
587  CatchScope->setHandler(I, CGM.getCXXABI().getCatchAllTypeInfo(), Handler);
588  }
589  }
590 }
591 
592 llvm::BasicBlock *
594  if (EHPersonality::get(*this).usesFuncletPads())
595  return getFuncletEHDispatchBlock(si);
596 
597  // The dispatch block for the end of the scope chain is a block that
598  // just resumes unwinding.
599  if (si == EHStack.stable_end())
600  return getEHResumeBlock(true);
601 
602  // Otherwise, we should look at the actual scope.
603  EHScope &scope = *EHStack.find(si);
604 
605  llvm::BasicBlock *dispatchBlock = scope.getCachedEHDispatchBlock();
606  if (!dispatchBlock) {
607  switch (scope.getKind()) {
608  case EHScope::Catch: {
609  // Apply a special case to a single catch-all.
610  EHCatchScope &catchScope = cast<EHCatchScope>(scope);
611  if (catchScope.getNumHandlers() == 1 &&
612  catchScope.getHandler(0).isCatchAll()) {
613  dispatchBlock = catchScope.getHandler(0).Block;
614 
615  // Otherwise, make a dispatch block.
616  } else {
617  dispatchBlock = createBasicBlock("catch.dispatch");
618  }
619  break;
620  }
621 
622  case EHScope::Cleanup:
623  dispatchBlock = createBasicBlock("ehcleanup");
624  break;
625 
626  case EHScope::Filter:
627  dispatchBlock = createBasicBlock("filter.dispatch");
628  break;
629 
630  case EHScope::Terminate:
631  dispatchBlock = getTerminateHandler();
632  break;
633 
634  case EHScope::PadEnd:
635  llvm_unreachable("PadEnd unnecessary for Itanium!");
636  }
637  scope.setCachedEHDispatchBlock(dispatchBlock);
638  }
639  return dispatchBlock;
640 }
641 
642 llvm::BasicBlock *
644  // Returning nullptr indicates that the previous dispatch block should unwind
645  // to caller.
646  if (SI == EHStack.stable_end())
647  return nullptr;
648 
649  // Otherwise, we should look at the actual scope.
650  EHScope &EHS = *EHStack.find(SI);
651 
652  llvm::BasicBlock *DispatchBlock = EHS.getCachedEHDispatchBlock();
653  if (DispatchBlock)
654  return DispatchBlock;
655 
656  if (EHS.getKind() == EHScope::Terminate)
657  DispatchBlock = getTerminateFunclet();
658  else
659  DispatchBlock = createBasicBlock();
660  CGBuilderTy Builder(*this, DispatchBlock);
661 
662  switch (EHS.getKind()) {
663  case EHScope::Catch:
664  DispatchBlock->setName("catch.dispatch");
665  break;
666 
667  case EHScope::Cleanup:
668  DispatchBlock->setName("ehcleanup");
669  break;
670 
671  case EHScope::Filter:
672  llvm_unreachable("exception specifications not handled yet!");
673 
674  case EHScope::Terminate:
675  DispatchBlock->setName("terminate");
676  break;
677 
678  case EHScope::PadEnd:
679  llvm_unreachable("PadEnd dispatch block missing!");
680  }
681  EHS.setCachedEHDispatchBlock(DispatchBlock);
682  return DispatchBlock;
683 }
684 
685 /// Check whether this is a non-EH scope, i.e. a scope which doesn't
686 /// affect exception handling. Currently, the only non-EH scopes are
687 /// normal-only cleanup scopes.
688 static bool isNonEHScope(const EHScope &S) {
689  switch (S.getKind()) {
690  case EHScope::Cleanup:
691  return !cast<EHCleanupScope>(S).isEHCleanup();
692  case EHScope::Filter:
693  case EHScope::Catch:
694  case EHScope::Terminate:
695  case EHScope::PadEnd:
696  return false;
697  }
698 
699  llvm_unreachable("Invalid EHScope Kind!");
700 }
701 
703  assert(EHStack.requiresLandingPad());
704  assert(!EHStack.empty());
705 
706  // If exceptions are disabled and SEH is not in use, then there is no invoke
707  // destination. SEH "works" even if exceptions are off. In practice, this
708  // means that C++ destructors and other EH cleanups don't run, which is
709  // consistent with MSVC's behavior.
710  const LangOptions &LO = CGM.getLangOpts();
711  if (!LO.Exceptions) {
712  if (!LO.Borland && !LO.MicrosoftExt)
713  return nullptr;
714  if (!currentFunctionUsesSEHTry())
715  return nullptr;
716  }
717 
718  // CUDA device code doesn't have exceptions.
719  if (LO.CUDA && LO.CUDAIsDevice)
720  return nullptr;
721 
722  // Check the innermost scope for a cached landing pad. If this is
723  // a non-EH cleanup, we'll check enclosing scopes in EmitLandingPad.
724  llvm::BasicBlock *LP = EHStack.begin()->getCachedLandingPad();
725  if (LP) return LP;
726 
727  const EHPersonality &Personality = EHPersonality::get(*this);
728 
729  if (!CurFn->hasPersonalityFn())
730  CurFn->setPersonalityFn(getOpaquePersonalityFn(CGM, Personality));
731 
732  if (Personality.usesFuncletPads()) {
733  // We don't need separate landing pads in the funclet model.
734  LP = getEHDispatchBlock(EHStack.getInnermostEHScope());
735  } else {
736  // Build the landing pad for this scope.
737  LP = EmitLandingPad();
738  }
739 
740  assert(LP);
741 
742  // Cache the landing pad on the innermost scope. If this is a
743  // non-EH scope, cache the landing pad on the enclosing scope, too.
744  for (EHScopeStack::iterator ir = EHStack.begin(); true; ++ir) {
745  ir->setCachedLandingPad(LP);
746  if (!isNonEHScope(*ir)) break;
747  }
748 
749  return LP;
750 }
751 
752 llvm::BasicBlock *CodeGenFunction::EmitLandingPad() {
753  assert(EHStack.requiresLandingPad());
754 
755  EHScope &innermostEHScope = *EHStack.find(EHStack.getInnermostEHScope());
756  switch (innermostEHScope.getKind()) {
757  case EHScope::Terminate:
758  return getTerminateLandingPad();
759 
760  case EHScope::PadEnd:
761  llvm_unreachable("PadEnd unnecessary for Itanium!");
762 
763  case EHScope::Catch:
764  case EHScope::Cleanup:
765  case EHScope::Filter:
766  if (llvm::BasicBlock *lpad = innermostEHScope.getCachedLandingPad())
767  return lpad;
768  }
769 
770  // Save the current IR generation state.
771  CGBuilderTy::InsertPoint savedIP = Builder.saveAndClearIP();
772  auto DL = ApplyDebugLocation::CreateDefaultArtificial(*this, CurEHLocation);
773 
774  // Create and configure the landing pad.
775  llvm::BasicBlock *lpad = createBasicBlock("lpad");
776  EmitBlock(lpad);
777 
778  llvm::LandingPadInst *LPadInst =
779  Builder.CreateLandingPad(llvm::StructType::get(Int8PtrTy, Int32Ty), 0);
780 
781  llvm::Value *LPadExn = Builder.CreateExtractValue(LPadInst, 0);
782  Builder.CreateStore(LPadExn, getExceptionSlot());
783  llvm::Value *LPadSel = Builder.CreateExtractValue(LPadInst, 1);
784  Builder.CreateStore(LPadSel, getEHSelectorSlot());
785 
786  // Save the exception pointer. It's safe to use a single exception
787  // pointer per function because EH cleanups can never have nested
788  // try/catches.
789  // Build the landingpad instruction.
790 
791  // Accumulate all the handlers in scope.
792  bool hasCatchAll = false;
793  bool hasCleanup = false;
794  bool hasFilter = false;
795  SmallVector<llvm::Value*, 4> filterTypes;
796  llvm::SmallPtrSet<llvm::Value*, 4> catchTypes;
797  for (EHScopeStack::iterator I = EHStack.begin(), E = EHStack.end(); I != E;
798  ++I) {
799 
800  switch (I->getKind()) {
801  case EHScope::Cleanup:
802  // If we have a cleanup, remember that.
803  hasCleanup = (hasCleanup || cast<EHCleanupScope>(*I).isEHCleanup());
804  continue;
805 
806  case EHScope::Filter: {
807  assert(I.next() == EHStack.end() && "EH filter is not end of EH stack");
808  assert(!hasCatchAll && "EH filter reached after catch-all");
809 
810  // Filter scopes get added to the landingpad in weird ways.
811  EHFilterScope &filter = cast<EHFilterScope>(*I);
812  hasFilter = true;
813 
814  // Add all the filter values.
815  for (unsigned i = 0, e = filter.getNumFilters(); i != e; ++i)
816  filterTypes.push_back(filter.getFilter(i));
817  goto done;
818  }
819 
820  case EHScope::Terminate:
821  // Terminate scopes are basically catch-alls.
822  assert(!hasCatchAll);
823  hasCatchAll = true;
824  goto done;
825 
826  case EHScope::Catch:
827  break;
828 
829  case EHScope::PadEnd:
830  llvm_unreachable("PadEnd unnecessary for Itanium!");
831  }
832 
833  EHCatchScope &catchScope = cast<EHCatchScope>(*I);
834  for (unsigned hi = 0, he = catchScope.getNumHandlers(); hi != he; ++hi) {
835  EHCatchScope::Handler handler = catchScope.getHandler(hi);
836  assert(handler.Type.Flags == 0 &&
837  "landingpads do not support catch handler flags");
838 
839  // If this is a catch-all, register that and abort.
840  if (!handler.Type.RTTI) {
841  assert(!hasCatchAll);
842  hasCatchAll = true;
843  goto done;
844  }
845 
846  // Check whether we already have a handler for this type.
847  if (catchTypes.insert(handler.Type.RTTI).second)
848  // If not, add it directly to the landingpad.
849  LPadInst->addClause(handler.Type.RTTI);
850  }
851  }
852 
853  done:
854  // If we have a catch-all, add null to the landingpad.
855  assert(!(hasCatchAll && hasFilter));
856  if (hasCatchAll) {
857  LPadInst->addClause(getCatchAllValue(*this));
858 
859  // If we have an EH filter, we need to add those handlers in the
860  // right place in the landingpad, which is to say, at the end.
861  } else if (hasFilter) {
862  // Create a filter expression: a constant array indicating which filter
863  // types there are. The personality routine only lands here if the filter
864  // doesn't match.
866  llvm::ArrayType *AType =
867  llvm::ArrayType::get(!filterTypes.empty() ?
868  filterTypes[0]->getType() : Int8PtrTy,
869  filterTypes.size());
870 
871  for (unsigned i = 0, e = filterTypes.size(); i != e; ++i)
872  Filters.push_back(cast<llvm::Constant>(filterTypes[i]));
873  llvm::Constant *FilterArray = llvm::ConstantArray::get(AType, Filters);
874  LPadInst->addClause(FilterArray);
875 
876  // Also check whether we need a cleanup.
877  if (hasCleanup)
878  LPadInst->setCleanup(true);
879 
880  // Otherwise, signal that we at least have cleanups.
881  } else if (hasCleanup) {
882  LPadInst->setCleanup(true);
883  }
884 
885  assert((LPadInst->getNumClauses() > 0 || LPadInst->isCleanup()) &&
886  "landingpad instruction has no clauses!");
887 
888  // Tell the backend how to generate the landing pad.
889  Builder.CreateBr(getEHDispatchBlock(EHStack.getInnermostEHScope()));
890 
891  // Restore the old IR generation state.
892  Builder.restoreIP(savedIP);
893 
894  return lpad;
895 }
896 
897 static void emitCatchPadBlock(CodeGenFunction &CGF, EHCatchScope &CatchScope) {
898  llvm::BasicBlock *DispatchBlock = CatchScope.getCachedEHDispatchBlock();
899  assert(DispatchBlock);
900 
901  CGBuilderTy::InsertPoint SavedIP = CGF.Builder.saveIP();
902  CGF.EmitBlockAfterUses(DispatchBlock);
903 
904  llvm::Value *ParentPad = CGF.CurrentFuncletPad;
905  if (!ParentPad)
906  ParentPad = llvm::ConstantTokenNone::get(CGF.getLLVMContext());
907  llvm::BasicBlock *UnwindBB =
908  CGF.getEHDispatchBlock(CatchScope.getEnclosingEHScope());
909 
910  unsigned NumHandlers = CatchScope.getNumHandlers();
911  llvm::CatchSwitchInst *CatchSwitch =
912  CGF.Builder.CreateCatchSwitch(ParentPad, UnwindBB, NumHandlers);
913 
914  // Test against each of the exception types we claim to catch.
915  for (unsigned I = 0; I < NumHandlers; ++I) {
916  const EHCatchScope::Handler &Handler = CatchScope.getHandler(I);
917 
918  CatchTypeInfo TypeInfo = Handler.Type;
919  if (!TypeInfo.RTTI)
920  TypeInfo.RTTI = llvm::Constant::getNullValue(CGF.VoidPtrTy);
921 
922  CGF.Builder.SetInsertPoint(Handler.Block);
923 
924  if (EHPersonality::get(CGF).isMSVCXXPersonality()) {
925  CGF.Builder.CreateCatchPad(
926  CatchSwitch, {TypeInfo.RTTI, CGF.Builder.getInt32(TypeInfo.Flags),
927  llvm::Constant::getNullValue(CGF.VoidPtrTy)});
928  } else {
929  CGF.Builder.CreateCatchPad(CatchSwitch, {TypeInfo.RTTI});
930  }
931 
932  CatchSwitch->addHandler(Handler.Block);
933  }
934  CGF.Builder.restoreIP(SavedIP);
935 }
936 
937 // Wasm uses Windows-style EH instructions, but it merges all catch clauses into
938 // one big catchpad, within which we use Itanium's landingpad-style selector
939 // comparison instructions.
941  EHCatchScope &CatchScope) {
942  llvm::BasicBlock *DispatchBlock = CatchScope.getCachedEHDispatchBlock();
943  assert(DispatchBlock);
944 
945  CGBuilderTy::InsertPoint SavedIP = CGF.Builder.saveIP();
946  CGF.EmitBlockAfterUses(DispatchBlock);
947 
948  llvm::Value *ParentPad = CGF.CurrentFuncletPad;
949  if (!ParentPad)
950  ParentPad = llvm::ConstantTokenNone::get(CGF.getLLVMContext());
951  llvm::BasicBlock *UnwindBB =
952  CGF.getEHDispatchBlock(CatchScope.getEnclosingEHScope());
953 
954  unsigned NumHandlers = CatchScope.getNumHandlers();
955  llvm::CatchSwitchInst *CatchSwitch =
956  CGF.Builder.CreateCatchSwitch(ParentPad, UnwindBB, NumHandlers);
957 
958  // We don't use a landingpad instruction, so generate intrinsic calls to
959  // provide exception and selector values.
960  llvm::BasicBlock *WasmCatchStartBlock = CGF.createBasicBlock("catch.start");
961  CatchSwitch->addHandler(WasmCatchStartBlock);
962  CGF.EmitBlockAfterUses(WasmCatchStartBlock);
963 
964  // Create a catchpad instruction.
966  for (unsigned I = 0, E = NumHandlers; I < E; ++I) {
967  const EHCatchScope::Handler &Handler = CatchScope.getHandler(I);
968  CatchTypeInfo TypeInfo = Handler.Type;
969  if (!TypeInfo.RTTI)
970  TypeInfo.RTTI = llvm::Constant::getNullValue(CGF.VoidPtrTy);
971  CatchTypes.push_back(TypeInfo.RTTI);
972  }
973  auto *CPI = CGF.Builder.CreateCatchPad(CatchSwitch, CatchTypes);
974 
975  // Create calls to wasm.get.exception and wasm.get.ehselector intrinsics.
976  // Before they are lowered appropriately later, they provide values for the
977  // exception and selector.
978  llvm::Function *GetExnFn =
979  CGF.CGM.getIntrinsic(llvm::Intrinsic::wasm_get_exception);
980  llvm::Function *GetSelectorFn =
981  CGF.CGM.getIntrinsic(llvm::Intrinsic::wasm_get_ehselector);
982  llvm::CallInst *Exn = CGF.Builder.CreateCall(GetExnFn, CPI);
983  CGF.Builder.CreateStore(Exn, CGF.getExceptionSlot());
984  llvm::CallInst *Selector = CGF.Builder.CreateCall(GetSelectorFn, CPI);
985 
986  llvm::Function *TypeIDFn = CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_typeid_for);
987 
988  // If there's only a single catch-all, branch directly to its handler.
989  if (CatchScope.getNumHandlers() == 1 &&
990  CatchScope.getHandler(0).isCatchAll()) {
991  CGF.Builder.CreateBr(CatchScope.getHandler(0).Block);
992  CGF.Builder.restoreIP(SavedIP);
993  return;
994  }
995 
996  // Test against each of the exception types we claim to catch.
997  for (unsigned I = 0, E = NumHandlers;; ++I) {
998  assert(I < E && "ran off end of handlers!");
999  const EHCatchScope::Handler &Handler = CatchScope.getHandler(I);
1000  CatchTypeInfo TypeInfo = Handler.Type;
1001  if (!TypeInfo.RTTI)
1002  TypeInfo.RTTI = llvm::Constant::getNullValue(CGF.VoidPtrTy);
1003 
1004  // Figure out the next block.
1005  llvm::BasicBlock *NextBlock;
1006 
1007  bool EmitNextBlock = false, NextIsEnd = false;
1008 
1009  // If this is the last handler, we're at the end, and the next block is a
1010  // block that contains a call to the rethrow function, so we can unwind to
1011  // the enclosing EH scope. The call itself will be generated later.
1012  if (I + 1 == E) {
1013  NextBlock = CGF.createBasicBlock("rethrow");
1014  EmitNextBlock = true;
1015  NextIsEnd = true;
1016 
1017  // If the next handler is a catch-all, we're at the end, and the
1018  // next block is that handler.
1019  } else if (CatchScope.getHandler(I + 1).isCatchAll()) {
1020  NextBlock = CatchScope.getHandler(I + 1).Block;
1021  NextIsEnd = true;
1022 
1023  // Otherwise, we're not at the end and we need a new block.
1024  } else {
1025  NextBlock = CGF.createBasicBlock("catch.fallthrough");
1026  EmitNextBlock = true;
1027  }
1028 
1029  // Figure out the catch type's index in the LSDA's type table.
1030  llvm::CallInst *TypeIndex = CGF.Builder.CreateCall(TypeIDFn, TypeInfo.RTTI);
1031  TypeIndex->setDoesNotThrow();
1032 
1033  llvm::Value *MatchesTypeIndex =
1034  CGF.Builder.CreateICmpEQ(Selector, TypeIndex, "matches");
1035  CGF.Builder.CreateCondBr(MatchesTypeIndex, Handler.Block, NextBlock);
1036 
1037  if (EmitNextBlock)
1038  CGF.EmitBlock(NextBlock);
1039  if (NextIsEnd)
1040  break;
1041  }
1042 
1043  CGF.Builder.restoreIP(SavedIP);
1044 }
1045 
1046 /// Emit the structure of the dispatch block for the given catch scope.
1047 /// It is an invariant that the dispatch block already exists.
1049  EHCatchScope &catchScope) {
1050  if (EHPersonality::get(CGF).isWasmPersonality())
1051  return emitWasmCatchPadBlock(CGF, catchScope);
1052  if (EHPersonality::get(CGF).usesFuncletPads())
1053  return emitCatchPadBlock(CGF, catchScope);
1054 
1055  llvm::BasicBlock *dispatchBlock = catchScope.getCachedEHDispatchBlock();
1056  assert(dispatchBlock);
1057 
1058  // If there's only a single catch-all, getEHDispatchBlock returned
1059  // that catch-all as the dispatch block.
1060  if (catchScope.getNumHandlers() == 1 &&
1061  catchScope.getHandler(0).isCatchAll()) {
1062  assert(dispatchBlock == catchScope.getHandler(0).Block);
1063  return;
1064  }
1065 
1066  CGBuilderTy::InsertPoint savedIP = CGF.Builder.saveIP();
1067  CGF.EmitBlockAfterUses(dispatchBlock);
1068 
1069  // Select the right handler.
1070  llvm::Function *llvm_eh_typeid_for =
1071  CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_typeid_for);
1072 
1073  // Load the selector value.
1074  llvm::Value *selector = CGF.getSelectorFromSlot();
1075 
1076  // Test against each of the exception types we claim to catch.
1077  for (unsigned i = 0, e = catchScope.getNumHandlers(); ; ++i) {
1078  assert(i < e && "ran off end of handlers!");
1079  const EHCatchScope::Handler &handler = catchScope.getHandler(i);
1080 
1081  llvm::Value *typeValue = handler.Type.RTTI;
1082  assert(handler.Type.Flags == 0 &&
1083  "landingpads do not support catch handler flags");
1084  assert(typeValue && "fell into catch-all case!");
1085  typeValue = CGF.Builder.CreateBitCast(typeValue, CGF.Int8PtrTy);
1086 
1087  // Figure out the next block.
1088  bool nextIsEnd;
1089  llvm::BasicBlock *nextBlock;
1090 
1091  // If this is the last handler, we're at the end, and the next
1092  // block is the block for the enclosing EH scope.
1093  if (i + 1 == e) {
1094  nextBlock = CGF.getEHDispatchBlock(catchScope.getEnclosingEHScope());
1095  nextIsEnd = true;
1096 
1097  // If the next handler is a catch-all, we're at the end, and the
1098  // next block is that handler.
1099  } else if (catchScope.getHandler(i+1).isCatchAll()) {
1100  nextBlock = catchScope.getHandler(i+1).Block;
1101  nextIsEnd = true;
1102 
1103  // Otherwise, we're not at the end and we need a new block.
1104  } else {
1105  nextBlock = CGF.createBasicBlock("catch.fallthrough");
1106  nextIsEnd = false;
1107  }
1108 
1109  // Figure out the catch type's index in the LSDA's type table.
1110  llvm::CallInst *typeIndex =
1111  CGF.Builder.CreateCall(llvm_eh_typeid_for, typeValue);
1112  typeIndex->setDoesNotThrow();
1113 
1114  llvm::Value *matchesTypeIndex =
1115  CGF.Builder.CreateICmpEQ(selector, typeIndex, "matches");
1116  CGF.Builder.CreateCondBr(matchesTypeIndex, handler.Block, nextBlock);
1117 
1118  // If the next handler is a catch-all, we're completely done.
1119  if (nextIsEnd) {
1120  CGF.Builder.restoreIP(savedIP);
1121  return;
1122  }
1123  // Otherwise we need to emit and continue at that block.
1124  CGF.EmitBlock(nextBlock);
1125  }
1126 }
1127 
1129  EHCatchScope &catchScope = cast<EHCatchScope>(*EHStack.begin());
1130  if (catchScope.hasEHBranches())
1131  emitCatchDispatchBlock(*this, catchScope);
1132  EHStack.popCatch();
1133 }
1134 
1135 void CodeGenFunction::ExitCXXTryStmt(const CXXTryStmt &S, bool IsFnTryBlock) {
1136  unsigned NumHandlers = S.getNumHandlers();
1137  EHCatchScope &CatchScope = cast<EHCatchScope>(*EHStack.begin());
1138  assert(CatchScope.getNumHandlers() == NumHandlers);
1139  llvm::BasicBlock *DispatchBlock = CatchScope.getCachedEHDispatchBlock();
1140 
1141  // If the catch was not required, bail out now.
1142  if (!CatchScope.hasEHBranches()) {
1143  CatchScope.clearHandlerBlocks();
1144  EHStack.popCatch();
1145  return;
1146  }
1147 
1148  // Emit the structure of the EH dispatch for this catch.
1149  emitCatchDispatchBlock(*this, CatchScope);
1150 
1151  // Copy the handler blocks off before we pop the EH stack. Emitting
1152  // the handlers might scribble on this memory.
1154  CatchScope.begin(), CatchScope.begin() + NumHandlers);
1155 
1156  EHStack.popCatch();
1157 
1158  // The fall-through block.
1159  llvm::BasicBlock *ContBB = createBasicBlock("try.cont");
1160 
1161  // We just emitted the body of the try; jump to the continue block.
1162  if (HaveInsertPoint())
1163  Builder.CreateBr(ContBB);
1164 
1165  // Determine if we need an implicit rethrow for all these catch handlers;
1166  // see the comment below.
1167  bool doImplicitRethrow = false;
1168  if (IsFnTryBlock)
1169  doImplicitRethrow = isa<CXXDestructorDecl>(CurCodeDecl) ||
1170  isa<CXXConstructorDecl>(CurCodeDecl);
1171 
1172  // Wasm uses Windows-style EH instructions, but merges all catch clauses into
1173  // one big catchpad. So we save the old funclet pad here before we traverse
1174  // each catch handler.
1175  SaveAndRestore<llvm::Instruction *> RestoreCurrentFuncletPad(
1176  CurrentFuncletPad);
1177  llvm::BasicBlock *WasmCatchStartBlock = nullptr;
1178  if (EHPersonality::get(*this).isWasmPersonality()) {
1179  auto *CatchSwitch =
1180  cast<llvm::CatchSwitchInst>(DispatchBlock->getFirstNonPHI());
1181  WasmCatchStartBlock = CatchSwitch->hasUnwindDest()
1182  ? CatchSwitch->getSuccessor(1)
1183  : CatchSwitch->getSuccessor(0);
1184  auto *CPI = cast<llvm::CatchPadInst>(WasmCatchStartBlock->getFirstNonPHI());
1185  CurrentFuncletPad = CPI;
1186  }
1187 
1188  // Perversely, we emit the handlers backwards precisely because we
1189  // want them to appear in source order. In all of these cases, the
1190  // catch block will have exactly one predecessor, which will be a
1191  // particular block in the catch dispatch. However, in the case of
1192  // a catch-all, one of the dispatch blocks will branch to two
1193  // different handlers, and EmitBlockAfterUses will cause the second
1194  // handler to be moved before the first.
1195  bool HasCatchAll = false;
1196  for (unsigned I = NumHandlers; I != 0; --I) {
1197  HasCatchAll |= Handlers[I - 1].isCatchAll();
1198  llvm::BasicBlock *CatchBlock = Handlers[I-1].Block;
1199  EmitBlockAfterUses(CatchBlock);
1200 
1201  // Catch the exception if this isn't a catch-all.
1202  const CXXCatchStmt *C = S.getHandler(I-1);
1203 
1204  // Enter a cleanup scope, including the catch variable and the
1205  // end-catch.
1206  RunCleanupsScope CatchScope(*this);
1207 
1208  // Initialize the catch variable and set up the cleanups.
1209  SaveAndRestore<llvm::Instruction *> RestoreCurrentFuncletPad(
1210  CurrentFuncletPad);
1211  CGM.getCXXABI().emitBeginCatch(*this, C);
1212 
1213  // Emit the PGO counter increment.
1214  incrementProfileCounter(C);
1215 
1216  // Perform the body of the catch.
1217  EmitStmt(C->getHandlerBlock());
1218 
1219  // [except.handle]p11:
1220  // The currently handled exception is rethrown if control
1221  // reaches the end of a handler of the function-try-block of a
1222  // constructor or destructor.
1223 
1224  // It is important that we only do this on fallthrough and not on
1225  // return. Note that it's illegal to put a return in a
1226  // constructor function-try-block's catch handler (p14), so this
1227  // really only applies to destructors.
1228  if (doImplicitRethrow && HaveInsertPoint()) {
1229  CGM.getCXXABI().emitRethrow(*this, /*isNoReturn*/false);
1230  Builder.CreateUnreachable();
1231  Builder.ClearInsertionPoint();
1232  }
1233 
1234  // Fall out through the catch cleanups.
1235  CatchScope.ForceCleanup();
1236 
1237  // Branch out of the try.
1238  if (HaveInsertPoint())
1239  Builder.CreateBr(ContBB);
1240  }
1241 
1242  // Because in wasm we merge all catch clauses into one big catchpad, in case
1243  // none of the types in catch handlers matches after we test against each of
1244  // them, we should unwind to the next EH enclosing scope. We generate a call
1245  // to rethrow function here to do that.
1246  if (EHPersonality::get(*this).isWasmPersonality() && !HasCatchAll) {
1247  assert(WasmCatchStartBlock);
1248  // Navigate for the "rethrow" block we created in emitWasmCatchPadBlock().
1249  // Wasm uses landingpad-style conditional branches to compare selectors, so
1250  // we follow the false destination for each of the cond branches to reach
1251  // the rethrow block.
1252  llvm::BasicBlock *RethrowBlock = WasmCatchStartBlock;
1253  while (llvm::Instruction *TI = RethrowBlock->getTerminator()) {
1254  auto *BI = cast<llvm::BranchInst>(TI);
1255  assert(BI->isConditional());
1256  RethrowBlock = BI->getSuccessor(1);
1257  }
1258  assert(RethrowBlock != WasmCatchStartBlock && RethrowBlock->empty());
1259  Builder.SetInsertPoint(RethrowBlock);
1260  llvm::Function *RethrowInCatchFn =
1261  CGM.getIntrinsic(llvm::Intrinsic::wasm_rethrow_in_catch);
1262  EmitNoreturnRuntimeCallOrInvoke(RethrowInCatchFn, {});
1263  }
1264 
1265  EmitBlock(ContBB);
1266  incrementProfileCounter(&S);
1267 }
1268 
1269 namespace {
1270  struct CallEndCatchForFinally final : EHScopeStack::Cleanup {
1271  llvm::Value *ForEHVar;
1272  llvm::FunctionCallee EndCatchFn;
1273  CallEndCatchForFinally(llvm::Value *ForEHVar,
1274  llvm::FunctionCallee EndCatchFn)
1275  : ForEHVar(ForEHVar), EndCatchFn(EndCatchFn) {}
1276 
1277  void Emit(CodeGenFunction &CGF, Flags flags) override {
1278  llvm::BasicBlock *EndCatchBB = CGF.createBasicBlock("finally.endcatch");
1279  llvm::BasicBlock *CleanupContBB =
1280  CGF.createBasicBlock("finally.cleanup.cont");
1281 
1282  llvm::Value *ShouldEndCatch =
1283  CGF.Builder.CreateFlagLoad(ForEHVar, "finally.endcatch");
1284  CGF.Builder.CreateCondBr(ShouldEndCatch, EndCatchBB, CleanupContBB);
1285  CGF.EmitBlock(EndCatchBB);
1286  CGF.EmitRuntimeCallOrInvoke(EndCatchFn); // catch-all, so might throw
1287  CGF.EmitBlock(CleanupContBB);
1288  }
1289  };
1290 
1291  struct PerformFinally final : EHScopeStack::Cleanup {
1292  const Stmt *Body;
1293  llvm::Value *ForEHVar;
1294  llvm::FunctionCallee EndCatchFn;
1295  llvm::FunctionCallee RethrowFn;
1296  llvm::Value *SavedExnVar;
1297 
1298  PerformFinally(const Stmt *Body, llvm::Value *ForEHVar,
1299  llvm::FunctionCallee EndCatchFn,
1300  llvm::FunctionCallee RethrowFn, llvm::Value *SavedExnVar)
1301  : Body(Body), ForEHVar(ForEHVar), EndCatchFn(EndCatchFn),
1302  RethrowFn(RethrowFn), SavedExnVar(SavedExnVar) {}
1303 
1304  void Emit(CodeGenFunction &CGF, Flags flags) override {
1305  // Enter a cleanup to call the end-catch function if one was provided.
1306  if (EndCatchFn)
1307  CGF.EHStack.pushCleanup<CallEndCatchForFinally>(NormalAndEHCleanup,
1308  ForEHVar, EndCatchFn);
1309 
1310  // Save the current cleanup destination in case there are
1311  // cleanups in the finally block.
1312  llvm::Value *SavedCleanupDest =
1314  "cleanup.dest.saved");
1315 
1316  // Emit the finally block.
1317  CGF.EmitStmt(Body);
1318 
1319  // If the end of the finally is reachable, check whether this was
1320  // for EH. If so, rethrow.
1321  if (CGF.HaveInsertPoint()) {
1322  llvm::BasicBlock *RethrowBB = CGF.createBasicBlock("finally.rethrow");
1323  llvm::BasicBlock *ContBB = CGF.createBasicBlock("finally.cont");
1324 
1325  llvm::Value *ShouldRethrow =
1326  CGF.Builder.CreateFlagLoad(ForEHVar, "finally.shouldthrow");
1327  CGF.Builder.CreateCondBr(ShouldRethrow, RethrowBB, ContBB);
1328 
1329  CGF.EmitBlock(RethrowBB);
1330  if (SavedExnVar) {
1331  CGF.EmitRuntimeCallOrInvoke(RethrowFn,
1332  CGF.Builder.CreateAlignedLoad(SavedExnVar, CGF.getPointerAlign()));
1333  } else {
1334  CGF.EmitRuntimeCallOrInvoke(RethrowFn);
1335  }
1336  CGF.Builder.CreateUnreachable();
1337 
1338  CGF.EmitBlock(ContBB);
1339 
1340  // Restore the cleanup destination.
1341  CGF.Builder.CreateStore(SavedCleanupDest,
1342  CGF.getNormalCleanupDestSlot());
1343  }
1344 
1345  // Leave the end-catch cleanup. As an optimization, pretend that
1346  // the fallthrough path was inaccessible; we've dynamically proven
1347  // that we're not in the EH case along that path.
1348  if (EndCatchFn) {
1349  CGBuilderTy::InsertPoint SavedIP = CGF.Builder.saveAndClearIP();
1350  CGF.PopCleanupBlock();
1351  CGF.Builder.restoreIP(SavedIP);
1352  }
1353 
1354  // Now make sure we actually have an insertion point or the
1355  // cleanup gods will hate us.
1356  CGF.EnsureInsertPoint();
1357  }
1358  };
1359 } // end anonymous namespace
1360 
1361 /// Enters a finally block for an implementation using zero-cost
1362 /// exceptions. This is mostly general, but hard-codes some
1363 /// language/ABI-specific behavior in the catch-all sections.
1365  llvm::FunctionCallee beginCatchFn,
1366  llvm::FunctionCallee endCatchFn,
1367  llvm::FunctionCallee rethrowFn) {
1368  assert((!!beginCatchFn) == (!!endCatchFn) &&
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 = rethrowFn.getFunctionType();
1381  SavedExnVar = nullptr;
1382  if (rethrowFnTy->getNumParams())
1383  SavedExnVar = CGF.CreateTempAlloca(CGF.Int8PtrTy, "finally.exn");
1384 
1385  // A finally block is a statement which must be executed on any edge
1386  // out of a given scope. Unlike a cleanup, the finally block may
1387  // contain arbitrary control flow leading out of itself. In
1388  // addition, finally blocks should always be executed, even if there
1389  // are no catch handlers higher on the stack. Therefore, we
1390  // surround the protected scope with a combination of a normal
1391  // cleanup (to catch attempts to break out of the block via normal
1392  // control flow) and an EH catch-all (semantically "outside" any try
1393  // statement to which the finally block might have been attached).
1394  // The finally block itself is generated in the context of a cleanup
1395  // which conditionally leaves the catch-all.
1396 
1397  // Jump destination for performing the finally block on an exception
1398  // edge. We'll never actually reach this block, so unreachable is
1399  // fine.
1400  RethrowDest = CGF.getJumpDestInCurrentScope(CGF.getUnreachableBlock());
1401 
1402  // Whether the finally block is being executed for EH purposes.
1403  ForEHVar = CGF.CreateTempAlloca(CGF.Builder.getInt1Ty(), "finally.for-eh");
1404  CGF.Builder.CreateFlagStore(false, ForEHVar);
1405 
1406  // Enter a normal cleanup which will perform the @finally block.
1407  CGF.EHStack.pushCleanup<PerformFinally>(NormalCleanup, body,
1408  ForEHVar, endCatchFn,
1409  rethrowFn, SavedExnVar);
1410 
1411  // Enter a catch-all scope.
1412  llvm::BasicBlock *catchBB = CGF.createBasicBlock("finally.catchall");
1413  EHCatchScope *catchScope = CGF.EHStack.pushCatch(1);
1414  catchScope->setCatchAllHandler(0, catchBB);
1415 }
1416 
1418  // Leave the finally catch-all.
1419  EHCatchScope &catchScope = cast<EHCatchScope>(*CGF.EHStack.begin());
1420  llvm::BasicBlock *catchBB = catchScope.getHandler(0).Block;
1421 
1422  CGF.popCatchScope();
1423 
1424  // If there are any references to the catch-all block, emit it.
1425  if (catchBB->use_empty()) {
1426  delete catchBB;
1427  } else {
1428  CGBuilderTy::InsertPoint savedIP = CGF.Builder.saveAndClearIP();
1429  CGF.EmitBlock(catchBB);
1430 
1431  llvm::Value *exn = nullptr;
1432 
1433  // If there's a begin-catch function, call it.
1434  if (BeginCatchFn) {
1435  exn = CGF.getExceptionFromSlot();
1436  CGF.EmitNounwindRuntimeCall(BeginCatchFn, exn);
1437  }
1438 
1439  // If we need to remember the exception pointer to rethrow later, do so.
1440  if (SavedExnVar) {
1441  if (!exn) exn = CGF.getExceptionFromSlot();
1442  CGF.Builder.CreateAlignedStore(exn, SavedExnVar, CGF.getPointerAlign());
1443  }
1444 
1445  // Tell the cleanups in the finally block that we're do this for EH.
1446  CGF.Builder.CreateFlagStore(true, ForEHVar);
1447 
1448  // Thread a jump through the finally cleanup.
1449  CGF.EmitBranchThroughCleanup(RethrowDest);
1450 
1451  CGF.Builder.restoreIP(savedIP);
1452  }
1453 
1454  // Finally, leave the @finally cleanup.
1455  CGF.PopCleanupBlock();
1456 }
1457 
1459  if (TerminateLandingPad)
1460  return TerminateLandingPad;
1461 
1462  CGBuilderTy::InsertPoint SavedIP = Builder.saveAndClearIP();
1463 
1464  // This will get inserted at the end of the function.
1465  TerminateLandingPad = createBasicBlock("terminate.lpad");
1466  Builder.SetInsertPoint(TerminateLandingPad);
1467 
1468  // Tell the backend that this is a landing pad.
1469  const EHPersonality &Personality = EHPersonality::get(*this);
1470 
1471  if (!CurFn->hasPersonalityFn())
1472  CurFn->setPersonalityFn(getOpaquePersonalityFn(CGM, Personality));
1473 
1474  llvm::LandingPadInst *LPadInst =
1475  Builder.CreateLandingPad(llvm::StructType::get(Int8PtrTy, Int32Ty), 0);
1476  LPadInst->addClause(getCatchAllValue(*this));
1477 
1478  llvm::Value *Exn = nullptr;
1479  if (getLangOpts().CPlusPlus)
1480  Exn = Builder.CreateExtractValue(LPadInst, 0);
1481  llvm::CallInst *terminateCall =
1482  CGM.getCXXABI().emitTerminateForUnexpectedException(*this, Exn);
1483  terminateCall->setDoesNotReturn();
1484  Builder.CreateUnreachable();
1485 
1486  // Restore the saved insertion state.
1487  Builder.restoreIP(SavedIP);
1488 
1489  return TerminateLandingPad;
1490 }
1491 
1493  if (TerminateHandler)
1494  return TerminateHandler;
1495 
1496  // Set up the terminate handler. This block is inserted at the very
1497  // end of the function by FinishFunction.
1498  TerminateHandler = createBasicBlock("terminate.handler");
1499  CGBuilderTy::InsertPoint SavedIP = Builder.saveAndClearIP();
1500  Builder.SetInsertPoint(TerminateHandler);
1501 
1502  llvm::Value *Exn = nullptr;
1503  if (getLangOpts().CPlusPlus)
1504  Exn = getExceptionFromSlot();
1505  llvm::CallInst *terminateCall =
1506  CGM.getCXXABI().emitTerminateForUnexpectedException(*this, Exn);
1507  terminateCall->setDoesNotReturn();
1508  Builder.CreateUnreachable();
1509 
1510  // Restore the saved insertion state.
1511  Builder.restoreIP(SavedIP);
1512 
1513  return TerminateHandler;
1514 }
1515 
1517  assert(EHPersonality::get(*this).usesFuncletPads() &&
1518  "use getTerminateLandingPad for non-funclet EH");
1519 
1520  llvm::BasicBlock *&TerminateFunclet = TerminateFunclets[CurrentFuncletPad];
1521  if (TerminateFunclet)
1522  return TerminateFunclet;
1523 
1524  CGBuilderTy::InsertPoint SavedIP = Builder.saveAndClearIP();
1525 
1526  // Set up the terminate handler. This block is inserted at the very
1527  // end of the function by FinishFunction.
1528  TerminateFunclet = createBasicBlock("terminate.handler");
1529  Builder.SetInsertPoint(TerminateFunclet);
1530 
1531  // Create the cleanuppad using the current parent pad as its token. Use 'none'
1532  // if this is a top-level terminate scope, which is the common case.
1533  SaveAndRestore<llvm::Instruction *> RestoreCurrentFuncletPad(
1534  CurrentFuncletPad);
1535  llvm::Value *ParentPad = CurrentFuncletPad;
1536  if (!ParentPad)
1537  ParentPad = llvm::ConstantTokenNone::get(CGM.getLLVMContext());
1538  CurrentFuncletPad = Builder.CreateCleanupPad(ParentPad);
1539 
1540  // Emit the __std_terminate call.
1541  llvm::Value *Exn = nullptr;
1542  // In case of wasm personality, we need to pass the exception value to
1543  // __clang_call_terminate function.
1544  if (getLangOpts().CPlusPlus &&
1546  llvm::Function *GetExnFn =
1547  CGM.getIntrinsic(llvm::Intrinsic::wasm_get_exception);
1548  Exn = Builder.CreateCall(GetExnFn, CurrentFuncletPad);
1549  }
1550  llvm::CallInst *terminateCall =
1551  CGM.getCXXABI().emitTerminateForUnexpectedException(*this, Exn);
1552  terminateCall->setDoesNotReturn();
1553  Builder.CreateUnreachable();
1554 
1555  // Restore the saved insertion state.
1556  Builder.restoreIP(SavedIP);
1557 
1558  return TerminateFunclet;
1559 }
1560 
1561 llvm::BasicBlock *CodeGenFunction::getEHResumeBlock(bool isCleanup) {
1562  if (EHResumeBlock) return EHResumeBlock;
1563 
1564  CGBuilderTy::InsertPoint SavedIP = Builder.saveIP();
1565 
1566  // We emit a jump to a notional label at the outermost unwind state.
1567  EHResumeBlock = createBasicBlock("eh.resume");
1568  Builder.SetInsertPoint(EHResumeBlock);
1569 
1570  const EHPersonality &Personality = EHPersonality::get(*this);
1571 
1572  // This can always be a call because we necessarily didn't find
1573  // anything on the EH stack which needs our help.
1574  const char *RethrowName = Personality.CatchallRethrowFn;
1575  if (RethrowName != nullptr && !isCleanup) {
1576  EmitRuntimeCall(getCatchallRethrowFn(CGM, RethrowName),
1577  getExceptionFromSlot())->setDoesNotReturn();
1578  Builder.CreateUnreachable();
1579  Builder.restoreIP(SavedIP);
1580  return EHResumeBlock;
1581  }
1582 
1583  // Recreate the landingpad's return value for the 'resume' instruction.
1584  llvm::Value *Exn = getExceptionFromSlot();
1585  llvm::Value *Sel = getSelectorFromSlot();
1586 
1587  llvm::Type *LPadType = llvm::StructType::get(Exn->getType(), Sel->getType());
1588  llvm::Value *LPadVal = llvm::UndefValue::get(LPadType);
1589  LPadVal = Builder.CreateInsertValue(LPadVal, Exn, 0, "lpad.val");
1590  LPadVal = Builder.CreateInsertValue(LPadVal, Sel, 1, "lpad.val");
1591 
1592  Builder.CreateResume(LPadVal);
1593  Builder.restoreIP(SavedIP);
1594  return EHResumeBlock;
1595 }
1596 
1598  EnterSEHTryStmt(S);
1599  {
1600  JumpDest TryExit = getJumpDestInCurrentScope("__try.__leave");
1601 
1602  SEHTryEpilogueStack.push_back(&TryExit);
1603  EmitStmt(S.getTryBlock());
1604  SEHTryEpilogueStack.pop_back();
1605 
1606  if (!TryExit.getBlock()->use_empty())
1607  EmitBlock(TryExit.getBlock(), /*IsFinished=*/true);
1608  else
1609  delete TryExit.getBlock();
1610  }
1611  ExitSEHTryStmt(S);
1612 }
1613 
1614 namespace {
1615 struct PerformSEHFinally final : EHScopeStack::Cleanup {
1616  llvm::Function *OutlinedFinally;
1617  PerformSEHFinally(llvm::Function *OutlinedFinally)
1618  : OutlinedFinally(OutlinedFinally) {}
1619 
1620  void Emit(CodeGenFunction &CGF, Flags F) override {
1621  ASTContext &Context = CGF.getContext();
1622  CodeGenModule &CGM = CGF.CGM;
1623 
1624  CallArgList Args;
1625 
1626  // Compute the two argument values.
1627  QualType ArgTys[2] = {Context.UnsignedCharTy, Context.VoidPtrTy};
1628  llvm::Value *FP = nullptr;
1629  // If CFG.IsOutlinedSEHHelper is true, then we are within a finally block.
1630  if (CGF.IsOutlinedSEHHelper) {
1631  FP = &CGF.CurFn->arg_begin()[1];
1632  } else {
1633  llvm::Function *LocalAddrFn =
1634  CGM.getIntrinsic(llvm::Intrinsic::localaddress);
1635  FP = CGF.Builder.CreateCall(LocalAddrFn);
1636  }
1637 
1638  llvm::Value *IsForEH =
1639  llvm::ConstantInt::get(CGF.ConvertType(ArgTys[0]), F.isForEHCleanup());
1640  Args.add(RValue::get(IsForEH), ArgTys[0]);
1641  Args.add(RValue::get(FP), ArgTys[1]);
1642 
1643  // Arrange a two-arg function info and type.
1644  const CGFunctionInfo &FnInfo =
1645  CGM.getTypes().arrangeBuiltinFunctionCall(Context.VoidTy, Args);
1646 
1647  auto Callee = CGCallee::forDirect(OutlinedFinally);
1648  CGF.EmitCall(FnInfo, Callee, ReturnValueSlot(), Args);
1649  }
1650 };
1651 } // end anonymous namespace
1652 
1653 namespace {
1654 /// Find all local variable captures in the statement.
1655 struct CaptureFinder : ConstStmtVisitor<CaptureFinder> {
1656  CodeGenFunction &ParentCGF;
1657  const VarDecl *ParentThis;
1659  Address SEHCodeSlot = Address::invalid();
1660  CaptureFinder(CodeGenFunction &ParentCGF, const VarDecl *ParentThis)
1661  : ParentCGF(ParentCGF), ParentThis(ParentThis) {}
1662 
1663  // Return true if we need to do any capturing work.
1664  bool foundCaptures() {
1665  return !Captures.empty() || SEHCodeSlot.isValid();
1666  }
1667 
1668  void Visit(const Stmt *S) {
1669  // See if this is a capture, then recurse.
1671  for (const Stmt *Child : S->children())
1672  if (Child)
1673  Visit(Child);
1674  }
1675 
1676  void VisitDeclRefExpr(const DeclRefExpr *E) {
1677  // If this is already a capture, just make sure we capture 'this'.
1679  Captures.insert(ParentThis);
1680  return;
1681  }
1682 
1683  const auto *D = dyn_cast<VarDecl>(E->getDecl());
1684  if (D && D->isLocalVarDeclOrParm() && D->hasLocalStorage())
1685  Captures.insert(D);
1686  }
1687 
1688  void VisitCXXThisExpr(const CXXThisExpr *E) {
1689  Captures.insert(ParentThis);
1690  }
1691 
1692  void VisitCallExpr(const CallExpr *E) {
1693  // We only need to add parent frame allocations for these builtins in x86.
1694  if (ParentCGF.getTarget().getTriple().getArch() != llvm::Triple::x86)
1695  return;
1696 
1697  unsigned ID = E->getBuiltinCallee();
1698  switch (ID) {
1699  case Builtin::BI__exception_code:
1700  case Builtin::BI_exception_code:
1701  // This is the simple case where we are the outermost finally. All we
1702  // have to do here is make sure we escape this and recover it in the
1703  // outlined handler.
1704  if (!SEHCodeSlot.isValid())
1705  SEHCodeSlot = ParentCGF.SEHCodeSlotStack.back();
1706  break;
1707  }
1708  }
1709 };
1710 } // end anonymous namespace
1711 
1713  Address ParentVar,
1714  llvm::Value *ParentFP) {
1715  llvm::CallInst *RecoverCall = nullptr;
1716  CGBuilderTy Builder(*this, AllocaInsertPt);
1717  if (auto *ParentAlloca = dyn_cast<llvm::AllocaInst>(ParentVar.getPointer())) {
1718  // Mark the variable escaped if nobody else referenced it and compute the
1719  // localescape index.
1720  auto InsertPair = ParentCGF.EscapedLocals.insert(
1721  std::make_pair(ParentAlloca, ParentCGF.EscapedLocals.size()));
1722  int FrameEscapeIdx = InsertPair.first->second;
1723  // call i8* @llvm.localrecover(i8* bitcast(@parentFn), i8* %fp, i32 N)
1724  llvm::Function *FrameRecoverFn = llvm::Intrinsic::getDeclaration(
1725  &CGM.getModule(), llvm::Intrinsic::localrecover);
1726  llvm::Constant *ParentI8Fn =
1727  llvm::ConstantExpr::getBitCast(ParentCGF.CurFn, Int8PtrTy);
1728  RecoverCall = Builder.CreateCall(
1729  FrameRecoverFn, {ParentI8Fn, ParentFP,
1730  llvm::ConstantInt::get(Int32Ty, FrameEscapeIdx)});
1731 
1732  } else {
1733  // If the parent didn't have an alloca, we're doing some nested outlining.
1734  // Just clone the existing localrecover call, but tweak the FP argument to
1735  // use our FP value. All other arguments are constants.
1736  auto *ParentRecover =
1737  cast<llvm::IntrinsicInst>(ParentVar.getPointer()->stripPointerCasts());
1738  assert(ParentRecover->getIntrinsicID() == llvm::Intrinsic::localrecover &&
1739  "expected alloca or localrecover in parent LocalDeclMap");
1740  RecoverCall = cast<llvm::CallInst>(ParentRecover->clone());
1741  RecoverCall->setArgOperand(1, ParentFP);
1742  RecoverCall->insertBefore(AllocaInsertPt);
1743  }
1744 
1745  // Bitcast the variable, rename it, and insert it in the local decl map.
1746  llvm::Value *ChildVar =
1747  Builder.CreateBitCast(RecoverCall, ParentVar.getType());
1748  ChildVar->setName(ParentVar.getName());
1749  return Address(ChildVar, ParentVar.getAlignment());
1750 }
1751 
1753  const Stmt *OutlinedStmt,
1754  bool IsFilter) {
1755  // Find all captures in the Stmt.
1756  CaptureFinder Finder(ParentCGF, ParentCGF.CXXABIThisDecl);
1757  Finder.Visit(OutlinedStmt);
1758 
1759  // We can exit early on x86_64 when there are no captures. We just have to
1760  // save the exception code in filters so that __exception_code() works.
1761  if (!Finder.foundCaptures() &&
1762  CGM.getTarget().getTriple().getArch() != llvm::Triple::x86) {
1763  if (IsFilter)
1764  EmitSEHExceptionCodeSave(ParentCGF, nullptr, nullptr);
1765  return;
1766  }
1767 
1768  llvm::Value *EntryFP = nullptr;
1769  CGBuilderTy Builder(CGM, AllocaInsertPt);
1770  if (IsFilter && CGM.getTarget().getTriple().getArch() == llvm::Triple::x86) {
1771  // 32-bit SEH filters need to be careful about FP recovery. The end of the
1772  // EH registration is passed in as the EBP physical register. We can
1773  // recover that with llvm.frameaddress(1).
1774  EntryFP = Builder.CreateCall(
1775  CGM.getIntrinsic(llvm::Intrinsic::frameaddress, AllocaInt8PtrTy),
1776  {Builder.getInt32(1)});
1777  } else {
1778  // Otherwise, for x64 and 32-bit finally functions, the parent FP is the
1779  // second parameter.
1780  auto AI = CurFn->arg_begin();
1781  ++AI;
1782  EntryFP = &*AI;
1783  }
1784 
1785  llvm::Value *ParentFP = EntryFP;
1786  if (IsFilter) {
1787  // Given whatever FP the runtime provided us in EntryFP, recover the true
1788  // frame pointer of the parent function. We only need to do this in filters,
1789  // since finally funclets recover the parent FP for us.
1790  llvm::Function *RecoverFPIntrin =
1791  CGM.getIntrinsic(llvm::Intrinsic::eh_recoverfp);
1792  llvm::Constant *ParentI8Fn =
1793  llvm::ConstantExpr::getBitCast(ParentCGF.CurFn, Int8PtrTy);
1794  ParentFP = Builder.CreateCall(RecoverFPIntrin, {ParentI8Fn, EntryFP});
1795  }
1796 
1797  // Create llvm.localrecover calls for all captures.
1798  for (const VarDecl *VD : Finder.Captures) {
1799  if (isa<ImplicitParamDecl>(VD)) {
1800  CGM.ErrorUnsupported(VD, "'this' captured by SEH");
1801  CXXThisValue = llvm::UndefValue::get(ConvertTypeForMem(VD->getType()));
1802  continue;
1803  }
1804  if (VD->getType()->isVariablyModifiedType()) {
1805  CGM.ErrorUnsupported(VD, "VLA captured by SEH");
1806  continue;
1807  }
1808  assert((isa<ImplicitParamDecl>(VD) || VD->isLocalVarDeclOrParm()) &&
1809  "captured non-local variable");
1810 
1811  // If this decl hasn't been declared yet, it will be declared in the
1812  // OutlinedStmt.
1813  auto I = ParentCGF.LocalDeclMap.find(VD);
1814  if (I == ParentCGF.LocalDeclMap.end())
1815  continue;
1816 
1817  Address ParentVar = I->second;
1818  setAddrOfLocalVar(
1819  VD, recoverAddrOfEscapedLocal(ParentCGF, ParentVar, ParentFP));
1820  }
1821 
1822  if (Finder.SEHCodeSlot.isValid()) {
1823  SEHCodeSlotStack.push_back(
1824  recoverAddrOfEscapedLocal(ParentCGF, Finder.SEHCodeSlot, ParentFP));
1825  }
1826 
1827  if (IsFilter)
1828  EmitSEHExceptionCodeSave(ParentCGF, ParentFP, EntryFP);
1829 }
1830 
1831 /// Arrange a function prototype that can be called by Windows exception
1832 /// handling personalities. On Win64, the prototype looks like:
1833 /// RetTy func(void *EHPtrs, void *ParentFP);
1835  bool IsFilter,
1836  const Stmt *OutlinedStmt) {
1837  SourceLocation StartLoc = OutlinedStmt->getBeginLoc();
1838 
1839  // Get the mangled function name.
1840  SmallString<128> Name;
1841  {
1842  llvm::raw_svector_ostream OS(Name);
1843  const NamedDecl *ParentSEHFn = ParentCGF.CurSEHParent;
1844  assert(ParentSEHFn && "No CurSEHParent!");
1845  MangleContext &Mangler = CGM.getCXXABI().getMangleContext();
1846  if (IsFilter)
1847  Mangler.mangleSEHFilterExpression(ParentSEHFn, OS);
1848  else
1849  Mangler.mangleSEHFinallyBlock(ParentSEHFn, OS);
1850  }
1851 
1852  FunctionArgList Args;
1853  if (CGM.getTarget().getTriple().getArch() != llvm::Triple::x86 || !IsFilter) {
1854  // All SEH finally functions take two parameters. Win64 filters take two
1855  // parameters. Win32 filters take no parameters.
1856  if (IsFilter) {
1857  Args.push_back(ImplicitParamDecl::Create(
1858  getContext(), /*DC=*/nullptr, StartLoc,
1859  &getContext().Idents.get("exception_pointers"),
1861  } else {
1862  Args.push_back(ImplicitParamDecl::Create(
1863  getContext(), /*DC=*/nullptr, StartLoc,
1864  &getContext().Idents.get("abnormal_termination"),
1866  }
1867  Args.push_back(ImplicitParamDecl::Create(
1868  getContext(), /*DC=*/nullptr, StartLoc,
1869  &getContext().Idents.get("frame_pointer"), getContext().VoidPtrTy,
1871  }
1872 
1873  QualType RetTy = IsFilter ? getContext().LongTy : getContext().VoidTy;
1874 
1875  const CGFunctionInfo &FnInfo =
1876  CGM.getTypes().arrangeBuiltinFunctionDeclaration(RetTy, Args);
1877 
1878  llvm::FunctionType *FnTy = CGM.getTypes().GetFunctionType(FnInfo);
1879  llvm::Function *Fn = llvm::Function::Create(
1880  FnTy, llvm::GlobalValue::InternalLinkage, Name.str(), &CGM.getModule());
1881 
1882  IsOutlinedSEHHelper = true;
1883 
1884  StartFunction(GlobalDecl(), RetTy, Fn, FnInfo, Args,
1885  OutlinedStmt->getBeginLoc(), OutlinedStmt->getBeginLoc());
1886  CurSEHParent = ParentCGF.CurSEHParent;
1887 
1888  CGM.SetLLVMFunctionAttributes(GlobalDecl(), FnInfo, CurFn);
1889  EmitCapturedLocals(ParentCGF, OutlinedStmt, IsFilter);
1890 }
1891 
1892 /// Create a stub filter function that will ultimately hold the code of the
1893 /// filter expression. The EH preparation passes in LLVM will outline the code
1894 /// from the main function body into this stub.
1895 llvm::Function *
1897  const SEHExceptStmt &Except) {
1898  const Expr *FilterExpr = Except.getFilterExpr();
1899  startOutlinedSEHHelper(ParentCGF, true, FilterExpr);
1900 
1901  // Emit the original filter expression, convert to i32, and return.
1902  llvm::Value *R = EmitScalarExpr(FilterExpr);
1903  R = Builder.CreateIntCast(R, ConvertType(getContext().LongTy),
1904  FilterExpr->getType()->isSignedIntegerType());
1905  Builder.CreateStore(R, ReturnValue);
1906 
1907  FinishFunction(FilterExpr->getEndLoc());
1908 
1909  return CurFn;
1910 }
1911 
1912 llvm::Function *
1914  const SEHFinallyStmt &Finally) {
1915  const Stmt *FinallyBlock = Finally.getBlock();
1916  startOutlinedSEHHelper(ParentCGF, false, FinallyBlock);
1917 
1918  // Emit the original filter expression, convert to i32, and return.
1919  EmitStmt(FinallyBlock);
1920 
1921  FinishFunction(FinallyBlock->getEndLoc());
1922 
1923  return CurFn;
1924 }
1925 
1927  llvm::Value *ParentFP,
1928  llvm::Value *EntryFP) {
1929  // Get the pointer to the EXCEPTION_POINTERS struct. This is returned by the
1930  // __exception_info intrinsic.
1931  if (CGM.getTarget().getTriple().getArch() != llvm::Triple::x86) {
1932  // On Win64, the info is passed as the first parameter to the filter.
1933  SEHInfo = &*CurFn->arg_begin();
1934  SEHCodeSlotStack.push_back(
1935  CreateMemTemp(getContext().IntTy, "__exception_code"));
1936  } else {
1937  // On Win32, the EBP on entry to the filter points to the end of an
1938  // exception registration object. It contains 6 32-bit fields, and the info
1939  // pointer is stored in the second field. So, GEP 20 bytes backwards and
1940  // load the pointer.
1941  SEHInfo = Builder.CreateConstInBoundsGEP1_32(Int8Ty, EntryFP, -20);
1942  SEHInfo = Builder.CreateBitCast(SEHInfo, Int8PtrTy->getPointerTo());
1943  SEHInfo = Builder.CreateAlignedLoad(Int8PtrTy, SEHInfo, getPointerAlign());
1944  SEHCodeSlotStack.push_back(recoverAddrOfEscapedLocal(
1945  ParentCGF, ParentCGF.SEHCodeSlotStack.back(), ParentFP));
1946  }
1947 
1948  // Save the exception code in the exception slot to unify exception access in
1949  // the filter function and the landing pad.
1950  // struct EXCEPTION_POINTERS {
1951  // EXCEPTION_RECORD *ExceptionRecord;
1952  // CONTEXT *ContextRecord;
1953  // };
1954  // int exceptioncode = exception_pointers->ExceptionRecord->ExceptionCode;
1955  llvm::Type *RecordTy = CGM.Int32Ty->getPointerTo();
1956  llvm::Type *PtrsTy = llvm::StructType::get(RecordTy, CGM.VoidPtrTy);
1957  llvm::Value *Ptrs = Builder.CreateBitCast(SEHInfo, PtrsTy->getPointerTo());
1958  llvm::Value *Rec = Builder.CreateStructGEP(PtrsTy, Ptrs, 0);
1959  Rec = Builder.CreateAlignedLoad(Rec, getPointerAlign());
1960  llvm::Value *Code = Builder.CreateAlignedLoad(Rec, getIntAlign());
1961  assert(!SEHCodeSlotStack.empty() && "emitting EH code outside of __except");
1962  Builder.CreateStore(Code, SEHCodeSlotStack.back());
1963 }
1964 
1966  // Sema should diagnose calling this builtin outside of a filter context, but
1967  // don't crash if we screw up.
1968  if (!SEHInfo)
1969  return llvm::UndefValue::get(Int8PtrTy);
1970  assert(SEHInfo->getType() == Int8PtrTy);
1971  return SEHInfo;
1972 }
1973 
1975  assert(!SEHCodeSlotStack.empty() && "emitting EH code outside of __except");
1976  return Builder.CreateLoad(SEHCodeSlotStack.back());
1977 }
1978 
1980  // Abnormal termination is just the first parameter to the outlined finally
1981  // helper.
1982  auto AI = CurFn->arg_begin();
1983  return Builder.CreateZExt(&*AI, Int32Ty);
1984 }
1985 
1987  llvm::Function *FinallyFunc) {
1988  EHStack.pushCleanup<PerformSEHFinally>(Kind, FinallyFunc);
1989 }
1990 
1992  CodeGenFunction HelperCGF(CGM, /*suppressNewContext=*/true);
1993  if (const SEHFinallyStmt *Finally = S.getFinallyHandler()) {
1994  // Outline the finally block.
1995  llvm::Function *FinallyFunc =
1996  HelperCGF.GenerateSEHFinallyFunction(*this, *Finally);
1997 
1998  // Push a cleanup for __finally blocks.
1999  EHStack.pushCleanup<PerformSEHFinally>(NormalAndEHCleanup, FinallyFunc);
2000  return;
2001  }
2002 
2003  // Otherwise, we must have an __except block.
2004  const SEHExceptStmt *Except = S.getExceptHandler();
2005  assert(Except);
2006  EHCatchScope *CatchScope = EHStack.pushCatch(1);
2007  SEHCodeSlotStack.push_back(
2008  CreateMemTemp(getContext().IntTy, "__exception_code"));
2009 
2010  // If the filter is known to evaluate to 1, then we can use the clause
2011  // "catch i8* null". We can't do this on x86 because the filter has to save
2012  // the exception code.
2013  llvm::Constant *C =
2015  getContext().IntTy);
2016  if (CGM.getTarget().getTriple().getArch() != llvm::Triple::x86 && C &&
2017  C->isOneValue()) {
2018  CatchScope->setCatchAllHandler(0, createBasicBlock("__except"));
2019  return;
2020  }
2021 
2022  // In general, we have to emit an outlined filter function. Use the function
2023  // in place of the RTTI typeinfo global that C++ EH uses.
2024  llvm::Function *FilterFunc =
2025  HelperCGF.GenerateSEHFilterFunction(*this, *Except);
2026  llvm::Constant *OpaqueFunc =
2027  llvm::ConstantExpr::getBitCast(FilterFunc, Int8PtrTy);
2028  CatchScope->setHandler(0, OpaqueFunc, createBasicBlock("__except.ret"));
2029 }
2030 
2032  // Just pop the cleanup if it's a __finally block.
2033  if (S.getFinallyHandler()) {
2034  PopCleanupBlock();
2035  return;
2036  }
2037 
2038  // Otherwise, we must have an __except block.
2039  const SEHExceptStmt *Except = S.getExceptHandler();
2040  assert(Except && "__try must have __finally xor __except");
2041  EHCatchScope &CatchScope = cast<EHCatchScope>(*EHStack.begin());
2042 
2043  // Don't emit the __except block if the __try block lacked invokes.
2044  // TODO: Model unwind edges from instructions, either with iload / istore or
2045  // a try body function.
2046  if (!CatchScope.hasEHBranches()) {
2047  CatchScope.clearHandlerBlocks();
2048  EHStack.popCatch();
2049  SEHCodeSlotStack.pop_back();
2050  return;
2051  }
2052 
2053  // The fall-through block.
2054  llvm::BasicBlock *ContBB = createBasicBlock("__try.cont");
2055 
2056  // We just emitted the body of the __try; jump to the continue block.
2057  if (HaveInsertPoint())
2058  Builder.CreateBr(ContBB);
2059 
2060  // Check if our filter function returned true.
2061  emitCatchDispatchBlock(*this, CatchScope);
2062 
2063  // Grab the block before we pop the handler.
2064  llvm::BasicBlock *CatchPadBB = CatchScope.getHandler(0).Block;
2065  EHStack.popCatch();
2066 
2067  EmitBlockAfterUses(CatchPadBB);
2068 
2069  // __except blocks don't get outlined into funclets, so immediately do a
2070  // catchret.
2071  llvm::CatchPadInst *CPI =
2072  cast<llvm::CatchPadInst>(CatchPadBB->getFirstNonPHI());
2073  llvm::BasicBlock *ExceptBB = createBasicBlock("__except");
2074  Builder.CreateCatchRet(CPI, ExceptBB);
2075  EmitBlock(ExceptBB);
2076 
2077  // On Win64, the exception code is returned in EAX. Copy it into the slot.
2078  if (CGM.getTarget().getTriple().getArch() != llvm::Triple::x86) {
2079  llvm::Function *SEHCodeIntrin =
2080  CGM.getIntrinsic(llvm::Intrinsic::eh_exceptioncode);
2081  llvm::Value *Code = Builder.CreateCall(SEHCodeIntrin, {CPI});
2082  Builder.CreateStore(Code, SEHCodeSlotStack.back());
2083  }
2084 
2085  // Emit the __except body.
2086  EmitStmt(Except->getBlock());
2087 
2088  // End the lifetime of the exception code.
2089  SEHCodeSlotStack.pop_back();
2090 
2091  if (HaveInsertPoint())
2092  Builder.CreateBr(ContBB);
2093 
2094  EmitBlock(ContBB);
2095 }
2096 
2098  // If this code is reachable then emit a stop point (if generating
2099  // debug info). We have to do this ourselves because we are on the
2100  // "simple" statement path.
2101  if (HaveInsertPoint())
2102  EmitStopPoint(&S);
2103 
2104  // This must be a __leave from a __finally block, which we warn on and is UB.
2105  // Just emit unreachable.
2106  if (!isSEHTryScope()) {
2107  Builder.CreateUnreachable();
2108  Builder.ClearInsertionPoint();
2109  return;
2110  }
2111 
2112  EmitBranchThroughCleanup(*SEHTryEpilogueStack.back());
2113 }
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:359
static llvm::FunctionCallee getFreeExceptionFn(CodeGenModule &CGM)
Definition: CGException.cpp:32
Represents a function declaration or definition.
Definition: Decl.h:1783
llvm::IntegerType * IntTy
int
EHScopeStack::stable_iterator getEnclosingEHScope() const
Definition: CGCleanup.h:137
Other implicit parameter.
Definition: Decl.h:1555
CompoundStmt * getBlock() const
Definition: Stmt.h:3269
Smart pointer class that efficiently represents Objective-C method names.
void setCatchAllHandler(unsigned I, llvm::BasicBlock *Block)
Definition: CGCleanup.h:192
CanQualType VoidPtrTy
Definition: ASTContext.h:1044
A (possibly-)qualified type.
Definition: Type.h:654
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:633
unsigned getNumExceptions() const
Return the number of types in the exception specification.
Definition: Type.h:4032
const Expr * getSubExpr() const
Definition: ExprCXX.h:1162
ConstStmtVisitor - This class implements a simple visitor for Stmt subclasses.
Definition: StmtVisitor.h:193
llvm::BasicBlock * getCachedEHDispatchBlock() const
Definition: CGCleanup.h:123
bool HaveInsertPoint() const
HaveInsertPoint - True if an insertion point is defined.
llvm::LLVMContext & getLLVMContext()
static const EHPersonality GNU_C_SJLJ
Definition: CGCleanup.h:615
void enter(CodeGenFunction &CGF, const Stmt *Finally, llvm::FunctionCallee beginCatchFn, llvm::FunctionCallee endCatchFn, llvm::FunctionCallee rethrowFn)
Enters a finally block for an implementation using zero-cost exceptions.
void EmitCXXTryStmt(const CXXTryStmt &S)
Stmt - This represents one statement.
Definition: Stmt.h:66
CXXCatchStmt * getHandler(unsigned i)
Definition: StmtCXX.h:107
static const EHPersonality MSVC_C_specific_handler
Definition: CGCleanup.h:627
const llvm::Triple & getTriple() const
Returns the target triple of the primary target.
Definition: TargetInfo.h:994
static const EHPersonality MSVC_CxxFrameHandler3
Definition: CGCleanup.h:628
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:2472
bool hasEHBranches() const
Definition: CGCleanup.h:131
Decl - This represents one declaration (or definition), e.g.
Definition: DeclBase.h:88
Stmt * getHandlerBlock() const
Definition: StmtCXX.h:51
const Decl * CurCodeDecl
CurCodeDecl - This is the inner-most code context, which includes blocks.
static const EHPersonality GNU_C
Definition: CGCleanup.h:614
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:6452
Represents Objective-C&#39;s @throw statement.
Definition: StmtObjC.h:332
CanQualType LongTy
Definition: ASTContext.h:1025
void EmitSEHExceptionCodeSave(CodeGenFunction &ParentCGF, llvm::Value *ParentFP, llvm::Value *EntryEBP)
bool usesSEHTry() const
Indicates the function uses __try.
Definition: Decl.h:2233
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...
unsigned getNumFilters() const
Definition: CGCleanup.h:460
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:52
bool ReturnValue(const T &V, APValue &R)
Convers a value to an APValue.
Definition: Interp.h:41
Represents a variable declaration or definition.
Definition: Decl.h:820
const T * getAs() const
Member-template getAs<specific type>&#39;.
Definition: Type.h:7002
llvm::FunctionCallee getTerminateFn()
Get the declaration of std::terminate for the platform.
Definition: CGException.cpp:50
unsigned getNumHandlers() const
Definition: CGCleanup.h:188
llvm::Value * getPointer() const
Definition: Address.h:37
iterator begin() const
Returns an iterator pointing to the innermost EH scope.
Definition: CGCleanup.h:566
llvm::BasicBlock * EmitLandingPad()
Emits a landing pad for the current EH stack.
A protected scope for zero-cost EH handling.
Definition: CGCleanup.h:43
Defines the Objective-C statement AST node classes.
A C++ throw-expression (C++ [except.throw]).
Definition: ExprCXX.h:1140
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:147
The collection of all-type qualifiers we support.
Definition: Type.h:143
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:39
const char * CatchallRethrowFn
Definition: CGCleanup.h:609
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:168
QualType getCaughtType() const
Definition: StmtCXX.cpp:19
SmallVector< Address, 1 > SEHCodeSlotStack
A stack of exception code slots.
SourceLocation getBeginLoc() const LLVM_READONLY
Definition: Stmt.cpp:275
static const EHPersonality GNU_CPlusPlus_SJLJ
Definition: CGCleanup.h:624
Denotes a cleanup that should run when a scope is exited using exceptional control flow (a throw stat...
Definition: EHScopeStack.h:80
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:53
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:462
class EHCatchScope * pushCatch(unsigned NumHandlers)
Push a set of catch handlers on the stack.
Definition: CGCleanup.cpp:244
bool isNeXTFamily() const
Is this runtime basically of the NeXT family of runtimes?
Definition: ObjCRuntime.h:134
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)
llvm::CallInst * EmitRuntimeCall(llvm::FunctionCallee callee, const Twine &name="")
QualType getExceptionType(unsigned i) const
Return the ith exception type, where 0 <= i < getNumExceptions().
Definition: Type.h:4040
iterator begin() const
Definition: CGCleanup.h:223
CharUnits getAlignment() const
Return the alignment of this pointer.
Definition: Address.h:66
child_range children()
Definition: Stmt.cpp:224
const Handler & getHandler(unsigned I) const
Definition: CGCleanup.h:208
static llvm::FunctionCallee getUnexpectedFn(CodeGenModule &CGM)
Definition: CGException.cpp:41
static const EHPersonality GNUstep_ObjC
Definition: CGCleanup.h:620
RangeSelector name(std::string ID)
Given a node with a "name", (like NamedDecl, DeclRefExpr or CxxCtorInitializer) selects the name&#39;s to...
bool IsOutlinedSEHHelper
True if the current function is an outlined SEH helper.
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:84
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:4226
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:1026
Represents the this expression in C++.
Definition: ExprCXX.h:1097
static ImplicitParamDecl * Create(ASTContext &C, DeclContext *DC, SourceLocation IdLoc, IdentifierInfo *Id, QualType T, ImplicitParamKind ParamKind)
Create implicit parameter.
Definition: Decl.cpp:4685
&#39;watchos&#39; is a variant of iOS for Apple&#39;s watchOS.
Definition: ObjCRuntime.h:48
bool isValid() const
Definition: Address.h:35
static const EHPersonality & getCPersonality(const TargetInfo &Target, const LangOptions &L)
Represents a prototype with parameter type info, e.g.
Definition: Type.h:3754
static const EHPersonality MSVC_except_handler
Definition: CGCleanup.h:626
static llvm::Constant * getOpaquePersonalityFn(CodeGenModule &CGM, const EHPersonality &Personality)
Exposes information about the current target.
Definition: TargetInfo.h:164
CatchTypeInfo Type
A type info value, or null (C++ null, not an LLVM null pointer) for a catch-all.
Definition: CGCleanup.h:157
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:108
static bool PersonalityHasOnlyCXXUses(llvm::Constant *Fn)
Check whether a personality function could reasonably be swapped for a C++ personality function...
static llvm::FunctionCallee getPersonalityFn(CodeGenModule &CGM, const EHPersonality &Personality)
&#39;macosx&#39; is the Apple-provided NeXT-derived runtime on Mac OS X platforms that use the non-fragile AB...
Definition: ObjCRuntime.h:34
static Address invalid()
Definition: Address.h:34
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:133
VarDecl * getExceptionDecl() const
Definition: StmtCXX.h:49
llvm::PointerType * getType() const
Return the type of the pointer value.
Definition: Address.h:43
void EmitSEHTryStmt(const SEHTryStmt &S)
void pushSEHCleanup(CleanupKind kind, llvm::Function *FinallyFunc)
llvm::BasicBlock * Block
The catch handler for this type.
Definition: CGCleanup.h:160
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:68
bool refersToEnclosingVariableOrCapture() const
Does this DeclRefExpr refer to an enclosing local or a captured variable?
Definition: Expr.h:1377
llvm::Value * getExceptionFromSlot()
Returns the contents of the function&#39;s exception object and selector slots.
static void emitCatchDispatchBlock(CodeGenFunction &CGF, EHCatchScope &catchScope)
Emit the structure of the dispatch block for the given catch scope.
llvm::LLVMContext & getLLVMContext()
const CGFunctionInfo & arrangeBuiltinFunctionCall(QualType resultType, const CallArgList &args)
Definition: CGCall.cpp:640
bool isSignedIntegerType() const
Return true if this is an integer type that is signed, according to C99 6.2.5p4 [char, signed char, short, int, long..], or an enum decl which has a signed representation.
Definition: Type.cpp:1928
QualType getType() const
Definition: Expr.h:137
static const EHPersonality GNU_ObjCXX
Definition: CGCleanup.h:621
bool hasTerminate() const
Does this runtime provide an objc_terminate function?
Definition: ObjCRuntime.h:347
clang::ObjCRuntime ObjCRuntime
Definition: LangOptions.h:257
llvm::PointerType * AllocaInt8PtrTy
static const EHPersonality GNU_ObjC_SEH
Definition: CGCleanup.h:619
const TargetInfo & getTarget() const
ValueDecl * getDecl()
Definition: Expr.h:1247
&#39;gnustep&#39; is the modern non-fragile GNUstep runtime.
Definition: ObjCRuntime.h:55
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:135
static llvm::FunctionCallee getCatchallRethrowFn(CodeGenModule &CGM, StringRef Name)
Definition: CGException.cpp:76
GlobalDecl - represents a global declaration.
Definition: GlobalDecl.h:40
SourceLocation getEndLoc() const LLVM_READONLY
Definition: Stmt.cpp:288
unsigned getBuiltinCallee() const
getBuiltinCallee - If this is a call to a builtin, return the builtin ID of the callee.
Definition: Expr.cpp:1471
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:141
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:106
unsigned getNumHandlers() const
Definition: StmtCXX.h:106
bool isVariablyModifiedType() const
Whether this type is a variably-modified type (C99 6.7.5).
Definition: Type.h:2166
&#39;objfw&#39; is the Objective-C runtime included in ObjFW
Definition: ObjCRuntime.h:58
llvm::BasicBlock * getUnreachableBlock()
RValue EmitCall(const CGFunctionInfo &CallInfo, const CGCallee &Callee, ReturnValueSlot ReturnValue, const CallArgList &Args, llvm::CallBase **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:3814
Kind getKind() const
Definition: ObjCRuntime.h:76
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:45
CanQualType VoidTy
Definition: ASTContext.h:1016
bool isObjCObjectPointerType() const
Definition: Type.h:6618
An aligned address.
Definition: Address.h:24
bool isWasmPersonality() const
Definition: CGCleanup.h:642
llvm::BasicBlock * getEHResumeBlock(bool isCleanup)
void setCachedEHDispatchBlock(llvm::BasicBlock *block)
Definition: CGCleanup.h:127
llvm::Instruction * CurrentFuncletPad
llvm::Value * getFilter(unsigned i) const
Definition: CGCleanup.h:467
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:77
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:37
ExceptionSpecificationType getExceptionSpecType() const
Get the kind of exception specification on this function.
Definition: Type.h:3989
SourceLocation getExprLoc() const LLVM_READONLY
getExprLoc - Return the preferred location for the arrow when diagnosing a problem with a generic exp...
Definition: Expr.cpp:224
static const EHPersonality NeXT_ObjC
Definition: CGCleanup.h:622
llvm::BasicBlock * getFuncletEHDispatchBlock(EHScopeStack::stable_iterator scope)
FunctionArgList - Type for representing both the decl and type of parameters to a function...
Definition: CGCall.h:355
CGFunctionInfo - Class to encapsulate the information about a function definition.
Kind getKind() const
Definition: CGCleanup.h:113
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:776
static bool LandingPadHasOnlyCXXUses(llvm::LandingPadInst *LPI)
Check whether a landingpad instruction only uses C++ features.
static const EHPersonality GNU_CPlusPlus_SEH
Definition: CGCleanup.h:625
The basic abstraction for the target Objective-C runtime.
Definition: ObjCRuntime.h:27
static const EHPersonality GNU_ObjC
Definition: CGCleanup.h:617
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:90
llvm::LoadInst * CreateLoad(Address Addr, const llvm::Twine &Name="")
Definition: CGBuilder.h:69
SEHExceptStmt * getExceptHandler() const
Returns 0 if not defined.
Definition: Stmt.cpp:1142
llvm::Function * getIntrinsic(unsigned IID, ArrayRef< llvm::Type *> Tys=None)
llvm::FunctionCallee CreateRuntimeFunction(llvm::FunctionType *Ty, StringRef Name, llvm::AttributeList ExtraAttrs=llvm::AttributeList(), bool Local=false, bool AssumeConvergent=false)
Create or return a runtime function declaration with the specified type and name. ...
llvm::StoreInst * CreateStore(llvm::Value *Val, Address Addr, bool IsVolatile=false)
Definition: CGBuilder.h:107
llvm::Module & getModule() const
Represents a __leave statement.
Definition: Stmt.h:3337
&#39;ios&#39; is the Apple-provided NeXT-derived runtime on iOS or the iOS simulator; it is always non-fragil...
Definition: ObjCRuntime.h:44
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:3098
static const EHPersonality GNU_CPlusPlus
Definition: CGCleanup.h:623
llvm::LoadInst * CreateFlagLoad(llvm::Value *Addr, const llvm::Twine &Name="")
Emit a load from an i1 flag variable.
Definition: CGBuilder.h:128
llvm::StringRef getName() const
Return the IR name of the pointer value.
Definition: Address.h:61
static const EHPersonality GNU_ObjC_SJLJ
Definition: CGCleanup.h:618
Internal linkage, which indicates that the entity can be referred to from within the translation unit...
Definition: Linkage.h:31
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:473
void EnterCXXTryStmt(const CXXTryStmt &S, bool IsFnTryBlock=false)
SEHFinallyStmt * getFinallyHandler() const
Definition: Stmt.cpp:1146
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:6336
Expr * getFilterExpr() const
Definition: Stmt.h:3228
llvm::BasicBlock * getTerminateLandingPad()
getTerminateLandingPad - Return a landing pad that just calls terminate.
CXXCatchStmt - This represents a C++ catch block.
Definition: StmtCXX.h:28
llvm::Type * ConvertType(QualType T)
Qualifiers getQualifiers() const
Retrieve the set of qualifiers applied to this type.
Definition: Type.h:6283
static const EHPersonality GNU_C_SEH
Definition: CGCleanup.h:616
The exceptions personality for a function.
Definition: CGCleanup.h:603
llvm::Constant * RTTI
Definition: CGCleanup.h:38
CompoundStmt * getTryBlock()
Definition: StmtCXX.h:99
llvm::Value * EmitSEHAbnormalTermination()
CallExpr - Represents a function call (C99 6.5.2.2, C++ [expr.call]).
Definition: Expr.h:2546
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:1025
An exceptions scope which filters exceptions thrown through it.
Definition: CGCleanup.h:437
A reference to a declared variable, function, enum, etc.
Definition: Expr.h:1171
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:1044
void EmitEndEHSpec(const Decl *D)
EmitEndEHSpec - Emit the end of the exception spec.
llvm::StoreInst * CreateAlignedStore(llvm::Value *Val, llvm::Value *Addr, CharUnits Align, bool IsVolatile=false)
Definition: CGBuilder.h:114
static const EHPersonality GNU_Wasm_CPlusPlus
Definition: CGCleanup.h:629
QualType getType() const
Definition: Decl.h:630
Information for lazily generating a cleanup.
Definition: EHScopeStack.h:146
This represents a decl that may have a name.
Definition: Decl.h:223
A non-stable pointer into the scope stack.
Definition: CGCleanup.h:502
void EmitBlockAfterUses(llvm::BasicBlock *BB)
EmitBlockAfterUses - Emit the given block somewhere hopefully near its uses, and leave the insertion ...
Definition: CGStmt.cpp:510
static void emitCatchPadBlock(CodeGenFunction &CGF, EHCatchScope &CatchScope)
llvm::CallInst * EmitNounwindRuntimeCall(llvm::FunctionCallee callee, const Twine &name="")
llvm::CallBase * EmitRuntimeCallOrInvoke(llvm::FunctionCallee callee, ArrayRef< llvm::Value *> args, const Twine &name="")
Emits a call or invoke instruction to the given runtime function.
Definition: CGCall.cpp:3774
CallArgList - Type for representing both the value and type of arguments in a call.
Definition: CGCall.h:261
void PopCleanupBlock(bool FallThroughIsBranchThrough=false)
PopCleanupBlock - Will pop the cleanup entry on the stack and process all branch fixups.
Definition: CGCleanup.cpp:644
void setHandler(unsigned I, llvm::Constant *Type, llvm::BasicBlock *Block)
Definition: CGCleanup.h:196
CompoundStmt * getTryBlock() const
Definition: Stmt.h:3313
CompoundStmt * getBlock() const
Definition: Stmt.h:3232
void EmitCXXThrowExpr(const CXXThrowExpr *E, bool KeepInsertionPoint=true)
bool isLocalVarDeclOrParm() const
Similar to isLocalVarDecl but also includes parameters.
Definition: Decl.h:1123
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)