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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 "CodeGenFunction.h"
14 #include "CGCXXABI.h"
15 #include "CGCleanup.h"
16 #include "CGObjCRuntime.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/Intrinsics.h"
25 #include "llvm/IR/IntrinsicInst.h"
26 #include "llvm/Support/SaveAndRestore.h"
27 
28 using namespace clang;
29 using namespace CodeGen;
30 
31 static llvm::FunctionCallee getFreeExceptionFn(CodeGenModule &CGM) {
32  // void __cxa_free_exception(void *thrown_exception);
33 
34  llvm::FunctionType *FTy =
35  llvm::FunctionType::get(CGM.VoidTy, CGM.Int8PtrTy, /*isVarArg=*/false);
36 
37  return CGM.CreateRuntimeFunction(FTy, "__cxa_free_exception");
38 }
39 
40 static llvm::FunctionCallee getUnexpectedFn(CodeGenModule &CGM) {
41  // void __cxa_call_unexpected(void *thrown_exception);
42 
43  llvm::FunctionType *FTy =
44  llvm::FunctionType::get(CGM.VoidTy, CGM.Int8PtrTy, /*isVarArg=*/false);
45 
46  return CGM.CreateRuntimeFunction(FTy, "__cxa_call_unexpected");
47 }
48 
49 llvm::FunctionCallee CodeGenModule::getTerminateFn() {
50  // void __terminate();
51 
52  llvm::FunctionType *FTy =
53  llvm::FunctionType::get(VoidTy, /*isVarArg=*/false);
54 
55  StringRef name;
56 
57  // In C++, use std::terminate().
58  if (getLangOpts().CPlusPlus &&
59  getTarget().getCXXABI().isItaniumFamily()) {
60  name = "_ZSt9terminatev";
61  } else if (getLangOpts().CPlusPlus &&
62  getTarget().getCXXABI().isMicrosoft()) {
63  if (getLangOpts().isCompatibleWithMSVC(LangOptions::MSVC2015))
64  name = "__std_terminate";
65  else
66  name = "?terminate@@YAXXZ";
67  } else if (getLangOpts().ObjC &&
69  name = "objc_terminate";
70  else
71  name = "abort";
72  return CreateRuntimeFunction(FTy, name);
73 }
74 
75 static llvm::FunctionCallee getCatchallRethrowFn(CodeGenModule &CGM,
76  StringRef Name) {
77  llvm::FunctionType *FTy =
78  llvm::FunctionType::get(CGM.VoidTy, CGM.Int8PtrTy, /*isVarArg=*/false);
79 
80  return CGM.CreateRuntimeFunction(FTy, Name);
81 }
82 
83 const EHPersonality EHPersonality::GNU_C = { "__gcc_personality_v0", nullptr };
84 const EHPersonality
85 EHPersonality::GNU_C_SJLJ = { "__gcc_personality_sj0", nullptr };
86 const EHPersonality
87 EHPersonality::GNU_C_SEH = { "__gcc_personality_seh0", nullptr };
88 const EHPersonality
89 EHPersonality::NeXT_ObjC = { "__objc_personality_v0", nullptr };
90 const EHPersonality
91 EHPersonality::GNU_CPlusPlus = { "__gxx_personality_v0", nullptr };
92 const EHPersonality
93 EHPersonality::GNU_CPlusPlus_SJLJ = { "__gxx_personality_sj0", nullptr };
94 const EHPersonality
95 EHPersonality::GNU_CPlusPlus_SEH = { "__gxx_personality_seh0", nullptr };
96 const EHPersonality
97 EHPersonality::GNU_ObjC = {"__gnu_objc_personality_v0", "objc_exception_throw"};
98 const EHPersonality
99 EHPersonality::GNU_ObjC_SJLJ = {"__gnu_objc_personality_sj0", "objc_exception_throw"};
100 const EHPersonality
101 EHPersonality::GNU_ObjC_SEH = {"__gnu_objc_personality_seh0", "objc_exception_throw"};
102 const EHPersonality
103 EHPersonality::GNU_ObjCXX = { "__gnustep_objcxx_personality_v0", nullptr };
104 const EHPersonality
105 EHPersonality::GNUstep_ObjC = { "__gnustep_objc_personality_v0", nullptr };
106 const EHPersonality
107 EHPersonality::MSVC_except_handler = { "_except_handler3", nullptr };
108 const EHPersonality
109 EHPersonality::MSVC_C_specific_handler = { "__C_specific_handler", nullptr };
110 const EHPersonality
111 EHPersonality::MSVC_CxxFrameHandler3 = { "__CxxFrameHandler3", nullptr };
112 const EHPersonality
113 EHPersonality::GNU_Wasm_CPlusPlus = { "__gxx_wasm_personality_v0", nullptr };
114 
115 static const EHPersonality &getCPersonality(const TargetInfo &Target,
116  const LangOptions &L) {
117  const llvm::Triple &T = Target.getTriple();
118  if (T.isWindowsMSVCEnvironment())
119  return EHPersonality::MSVC_CxxFrameHandler3;
120  if (L.SjLjExceptions)
122  if (L.DWARFExceptions)
123  return EHPersonality::GNU_C;
124  if (L.SEHExceptions)
126  return EHPersonality::GNU_C;
127 }
128 
129 static const EHPersonality &getObjCPersonality(const TargetInfo &Target,
130  const LangOptions &L) {
131  const llvm::Triple &T = Target.getTriple();
132  if (T.isWindowsMSVCEnvironment())
133  return EHPersonality::MSVC_CxxFrameHandler3;
134 
135  switch (L.ObjCRuntime.getKind()) {
137  return getCPersonality(Target, L);
138  case ObjCRuntime::MacOSX:
139  case ObjCRuntime::iOS:
143  if (L.ObjCRuntime.getVersion() >= VersionTuple(1, 7))
144  return EHPersonality::GNUstep_ObjC;
145  LLVM_FALLTHROUGH;
146  case ObjCRuntime::GCC:
147  case ObjCRuntime::ObjFW:
148  if (L.SjLjExceptions)
150  if (L.SEHExceptions)
153  }
154  llvm_unreachable("bad runtime kind");
155 }
156 
157 static const EHPersonality &getCXXPersonality(const TargetInfo &Target,
158  const LangOptions &L) {
159  const llvm::Triple &T = Target.getTriple();
160  if (T.isWindowsMSVCEnvironment())
161  return EHPersonality::MSVC_CxxFrameHandler3;
162  if (L.SjLjExceptions)
164  if (L.DWARFExceptions)
166  if (L.SEHExceptions)
168  if (L.WasmExceptions)
171 }
172 
173 /// Determines the personality function to use when both C++
174 /// and Objective-C exceptions are being caught.
175 static const EHPersonality &getObjCXXPersonality(const TargetInfo &Target,
176  const LangOptions &L) {
177  if (Target.getTriple().isWindowsMSVCEnvironment())
178  return EHPersonality::MSVC_CxxFrameHandler3;
179 
180  switch (L.ObjCRuntime.getKind()) {
181  // In the fragile ABI, just use C++ exception handling and hope
182  // they're not doing crazy exception mixing.
184  return getCXXPersonality(Target, L);
185 
186  // The ObjC personality defers to the C++ personality for non-ObjC
187  // handlers. Unlike the C++ case, we use the same personality
188  // function on targets using (backend-driven) SJLJ EH.
189  case ObjCRuntime::MacOSX:
190  case ObjCRuntime::iOS:
192  return getObjCPersonality(Target, L);
193 
196 
197  // The GCC runtime's personality function inherently doesn't support
198  // mixed EH. Use the ObjC personality just to avoid returning null.
199  case ObjCRuntime::GCC:
200  case ObjCRuntime::ObjFW:
201  return getObjCPersonality(Target, L);
202  }
203  llvm_unreachable("bad runtime kind");
204 }
205 
206 static const EHPersonality &getSEHPersonalityMSVC(const llvm::Triple &T) {
207  if (T.getArch() == llvm::Triple::x86)
208  return EHPersonality::MSVC_except_handler;
210 }
211 
213  const FunctionDecl *FD) {
214  const llvm::Triple &T = CGM.getTarget().getTriple();
215  const LangOptions &L = CGM.getLangOpts();
216  const TargetInfo &Target = CGM.getTarget();
217 
218  // Functions using SEH get an SEH personality.
219  if (FD && FD->usesSEHTry())
220  return getSEHPersonalityMSVC(T);
221 
222  if (L.ObjC)
223  return L.CPlusPlus ? getObjCXXPersonality(Target, L)
224  : getObjCPersonality(Target, L);
225  return L.CPlusPlus ? getCXXPersonality(Target, L)
226  : getCPersonality(Target, L);
227 }
228 
230  const auto *FD = CGF.CurCodeDecl;
231  // For outlined finallys and filters, use the SEH personality in case they
232  // contain more SEH. This mostly only affects finallys. Filters could
233  // hypothetically use gnu statement expressions to sneak in nested SEH.
234  FD = FD ? FD : CGF.CurSEHParent;
235  return get(CGF.CGM, dyn_cast_or_null<FunctionDecl>(FD));
236 }
237 
238 static llvm::FunctionCallee getPersonalityFn(CodeGenModule &CGM,
239  const EHPersonality &Personality) {
240  return CGM.CreateRuntimeFunction(llvm::FunctionType::get(CGM.Int32Ty, true),
241  Personality.PersonalityFn,
242  llvm::AttributeList(), /*Local=*/true);
243 }
244 
245 static llvm::Constant *getOpaquePersonalityFn(CodeGenModule &CGM,
246  const EHPersonality &Personality) {
247  llvm::FunctionCallee Fn = getPersonalityFn(CGM, Personality);
248  llvm::PointerType* Int8PtrTy = llvm::PointerType::get(
249  llvm::Type::getInt8Ty(CGM.getLLVMContext()),
250  CGM.getDataLayout().getProgramAddressSpace());
251 
252  return llvm::ConstantExpr::getBitCast(cast<llvm::Constant>(Fn.getCallee()),
253  Int8PtrTy);
254 }
255 
256 /// Check whether a landingpad instruction only uses C++ features.
257 static bool LandingPadHasOnlyCXXUses(llvm::LandingPadInst *LPI) {
258  for (unsigned I = 0, E = LPI->getNumClauses(); I != E; ++I) {
259  // Look for something that would've been returned by the ObjC
260  // runtime's GetEHType() method.
261  llvm::Value *Val = LPI->getClause(I)->stripPointerCasts();
262  if (LPI->isCatch(I)) {
263  // Check if the catch value has the ObjC prefix.
264  if (llvm::GlobalVariable *GV = dyn_cast<llvm::GlobalVariable>(Val))
265  // ObjC EH selector entries are always global variables with
266  // names starting like this.
267  if (GV->getName().startswith("OBJC_EHTYPE"))
268  return false;
269  } else {
270  // Check if any of the filter values have the ObjC prefix.
271  llvm::Constant *CVal = cast<llvm::Constant>(Val);
272  for (llvm::User::op_iterator
273  II = CVal->op_begin(), IE = CVal->op_end(); II != IE; ++II) {
274  if (llvm::GlobalVariable *GV =
275  cast<llvm::GlobalVariable>((*II)->stripPointerCasts()))
276  // ObjC EH selector entries are always global variables with
277  // names starting like this.
278  if (GV->getName().startswith("OBJC_EHTYPE"))
279  return false;
280  }
281  }
282  }
283  return true;
284 }
285 
286 /// Check whether a personality function could reasonably be swapped
287 /// for a C++ personality function.
288 static bool PersonalityHasOnlyCXXUses(llvm::Constant *Fn) {
289  for (llvm::User *U : Fn->users()) {
290  // Conditionally white-list bitcasts.
291  if (llvm::ConstantExpr *CE = dyn_cast<llvm::ConstantExpr>(U)) {
292  if (CE->getOpcode() != llvm::Instruction::BitCast) return false;
293  if (!PersonalityHasOnlyCXXUses(CE))
294  return false;
295  continue;
296  }
297 
298  // Otherwise it must be a function.
299  llvm::Function *F = dyn_cast<llvm::Function>(U);
300  if (!F) return false;
301 
302  for (auto BB = F->begin(), E = F->end(); BB != E; ++BB) {
303  if (BB->isLandingPad())
304  if (!LandingPadHasOnlyCXXUses(BB->getLandingPadInst()))
305  return false;
306  }
307  }
308 
309  return true;
310 }
311 
312 /// Try to use the C++ personality function in ObjC++. Not doing this
313 /// can cause some incompatibilities with gcc, which is more
314 /// aggressive about only using the ObjC++ personality in a function
315 /// when it really needs it.
316 void CodeGenModule::SimplifyPersonality() {
317  // If we're not in ObjC++ -fexceptions, there's nothing to do.
318  if (!LangOpts.CPlusPlus || !LangOpts.ObjC || !LangOpts.Exceptions)
319  return;
320 
321  // Both the problem this endeavors to fix and the way the logic
322  // above works is specific to the NeXT runtime.
323  if (!LangOpts.ObjCRuntime.isNeXTFamily())
324  return;
325 
326  const EHPersonality &ObjCXX = EHPersonality::get(*this, /*FD=*/nullptr);
327  const EHPersonality &CXX = getCXXPersonality(getTarget(), LangOpts);
328  if (&ObjCXX == &CXX)
329  return;
330 
331  assert(std::strcmp(ObjCXX.PersonalityFn, CXX.PersonalityFn) != 0 &&
332  "Different EHPersonalities using the same personality function.");
333 
334  llvm::Function *Fn = getModule().getFunction(ObjCXX.PersonalityFn);
335 
336  // Nothing to do if it's unused.
337  if (!Fn || Fn->use_empty()) return;
338 
339  // Can't do the optimization if it has non-C++ uses.
340  if (!PersonalityHasOnlyCXXUses(Fn)) return;
341 
342  // Create the C++ personality function and kill off the old
343  // function.
344  llvm::FunctionCallee CXXFn = getPersonalityFn(*this, CXX);
345 
346  // This can happen if the user is screwing with us.
347  if (Fn->getType() != CXXFn.getCallee()->getType())
348  return;
349 
350  Fn->replaceAllUsesWith(CXXFn.getCallee());
351  Fn->eraseFromParent();
352 }
353 
354 /// Returns the value to inject into a selector to indicate the
355 /// presence of a catch-all.
356 static llvm::Constant *getCatchAllValue(CodeGenFunction &CGF) {
357  // Possibly we should use @llvm.eh.catch.all.value here.
358  return llvm::ConstantPointerNull::get(CGF.Int8PtrTy);
359 }
360 
361 namespace {
362  /// A cleanup to free the exception object if its initialization
363  /// throws.
364  struct FreeException final : EHScopeStack::Cleanup {
365  llvm::Value *exn;
366  FreeException(llvm::Value *exn) : exn(exn) {}
367  void Emit(CodeGenFunction &CGF, Flags flags) override {
369  }
370  };
371 } // end anonymous namespace
372 
373 // Emits an exception expression into the given location. This
374 // differs from EmitAnyExprToMem only in that, if a final copy-ctor
375 // call is required, an exception within that copy ctor causes
376 // std::terminate to be invoked.
378  // Make sure the exception object is cleaned up if there's an
379  // exception during initialization.
380  pushFullExprCleanup<FreeException>(EHCleanup, addr.getPointer());
381  EHScopeStack::stable_iterator cleanup = EHStack.stable_begin();
382 
383  // __cxa_allocate_exception returns a void*; we need to cast this
384  // to the appropriate type for the object.
385  llvm::Type *ty = ConvertTypeForMem(e->getType())->getPointerTo();
386  Address typedAddr = Builder.CreateBitCast(addr, ty);
387 
388  // FIXME: this isn't quite right! If there's a final unelided call
389  // to a copy constructor, then according to [except.terminate]p1 we
390  // must call std::terminate() if that constructor throws, because
391  // technically that copy occurs after the exception expression is
392  // evaluated but before the exception is caught. But the best way
393  // to handle that is to teach EmitAggExpr to do the final copy
394  // differently if it can't be elided.
395  EmitAnyExprToMem(e, typedAddr, e->getType().getQualifiers(),
396  /*IsInit*/ true);
397 
398  // Deactivate the cleanup block.
399  DeactivateCleanupBlock(cleanup,
400  cast<llvm::Instruction>(typedAddr.getPointer()));
401 }
402 
404  if (!ExceptionSlot)
405  ExceptionSlot = CreateTempAlloca(Int8PtrTy, "exn.slot");
406  return Address(ExceptionSlot, getPointerAlign());
407 }
408 
410  if (!EHSelectorSlot)
411  EHSelectorSlot = CreateTempAlloca(Int32Ty, "ehselector.slot");
412  return Address(EHSelectorSlot, CharUnits::fromQuantity(4));
413 }
414 
416  return Builder.CreateLoad(getExceptionSlot(), "exn");
417 }
418 
420  return Builder.CreateLoad(getEHSelectorSlot(), "sel");
421 }
422 
424  bool KeepInsertionPoint) {
425  if (const Expr *SubExpr = E->getSubExpr()) {
426  QualType ThrowType = SubExpr->getType();
427  if (ThrowType->isObjCObjectPointerType()) {
428  const Stmt *ThrowStmt = E->getSubExpr();
429  const ObjCAtThrowStmt S(E->getExprLoc(), const_cast<Stmt *>(ThrowStmt));
430  CGM.getObjCRuntime().EmitThrowStmt(*this, S, false);
431  } else {
432  CGM.getCXXABI().emitThrow(*this, E);
433  }
434  } else {
435  CGM.getCXXABI().emitRethrow(*this, /*isNoReturn=*/true);
436  }
437 
438  // throw is an expression, and the expression emitters expect us
439  // to leave ourselves at a valid insertion point.
440  if (KeepInsertionPoint)
441  EmitBlock(createBasicBlock("throw.cont"));
442 }
443 
445  if (!CGM.getLangOpts().CXXExceptions)
446  return;
447 
448  const FunctionDecl* FD = dyn_cast_or_null<FunctionDecl>(D);
449  if (!FD) {
450  // Check if CapturedDecl is nothrow and create terminate scope for it.
451  if (const CapturedDecl* CD = dyn_cast_or_null<CapturedDecl>(D)) {
452  if (CD->isNothrow())
453  EHStack.pushTerminate();
454  }
455  return;
456  }
457  const FunctionProtoType *Proto = FD->getType()->getAs<FunctionProtoType>();
458  if (!Proto)
459  return;
460 
462  if (isNoexceptExceptionSpec(EST) && Proto->canThrow() == CT_Cannot) {
463  // noexcept functions are simple terminate scopes.
464  EHStack.pushTerminate();
465  } else if (EST == EST_Dynamic || EST == EST_DynamicNone) {
466  // TODO: Revisit exception specifications for the MS ABI. There is a way to
467  // encode these in an object file but MSVC doesn't do anything with it.
468  if (getTarget().getCXXABI().isMicrosoft())
469  return;
470  unsigned NumExceptions = Proto->getNumExceptions();
471  EHFilterScope *Filter = EHStack.pushFilter(NumExceptions);
472 
473  for (unsigned I = 0; I != NumExceptions; ++I) {
474  QualType Ty = Proto->getExceptionType(I);
475  QualType ExceptType = Ty.getNonReferenceType().getUnqualifiedType();
476  llvm::Value *EHType = CGM.GetAddrOfRTTIDescriptor(ExceptType,
477  /*ForEH=*/true);
478  Filter->setFilter(I, EHType);
479  }
480  }
481 }
482 
483 /// Emit the dispatch block for a filter scope if necessary.
485  EHFilterScope &filterScope) {
486  llvm::BasicBlock *dispatchBlock = filterScope.getCachedEHDispatchBlock();
487  if (!dispatchBlock) return;
488  if (dispatchBlock->use_empty()) {
489  delete dispatchBlock;
490  return;
491  }
492 
493  CGF.EmitBlockAfterUses(dispatchBlock);
494 
495  // If this isn't a catch-all filter, we need to check whether we got
496  // here because the filter triggered.
497  if (filterScope.getNumFilters()) {
498  // Load the selector value.
499  llvm::Value *selector = CGF.getSelectorFromSlot();
500  llvm::BasicBlock *unexpectedBB = CGF.createBasicBlock("ehspec.unexpected");
501 
502  llvm::Value *zero = CGF.Builder.getInt32(0);
503  llvm::Value *failsFilter =
504  CGF.Builder.CreateICmpSLT(selector, zero, "ehspec.fails");
505  CGF.Builder.CreateCondBr(failsFilter, unexpectedBB,
506  CGF.getEHResumeBlock(false));
507 
508  CGF.EmitBlock(unexpectedBB);
509  }
510 
511  // Call __cxa_call_unexpected. This doesn't need to be an invoke
512  // because __cxa_call_unexpected magically filters exceptions
513  // according to the last landing pad the exception was thrown
514  // into. Seriously.
515  llvm::Value *exn = CGF.getExceptionFromSlot();
516  CGF.EmitRuntimeCall(getUnexpectedFn(CGF.CGM), exn)
517  ->setDoesNotReturn();
518  CGF.Builder.CreateUnreachable();
519 }
520 
522  if (!CGM.getLangOpts().CXXExceptions)
523  return;
524 
525  const FunctionDecl* FD = dyn_cast_or_null<FunctionDecl>(D);
526  if (!FD) {
527  // Check if CapturedDecl is nothrow and pop terminate scope for it.
528  if (const CapturedDecl* CD = dyn_cast_or_null<CapturedDecl>(D)) {
529  if (CD->isNothrow())
530  EHStack.popTerminate();
531  }
532  return;
533  }
534  const FunctionProtoType *Proto = FD->getType()->getAs<FunctionProtoType>();
535  if (!Proto)
536  return;
537 
539  if (isNoexceptExceptionSpec(EST) && Proto->canThrow() == CT_Cannot) {
540  EHStack.popTerminate();
541  } else if (EST == EST_Dynamic || EST == EST_DynamicNone) {
542  // TODO: Revisit exception specifications for the MS ABI. There is a way to
543  // encode these in an object file but MSVC doesn't do anything with it.
544  if (getTarget().getCXXABI().isMicrosoft())
545  return;
546  EHFilterScope &filterScope = cast<EHFilterScope>(*EHStack.begin());
547  emitFilterDispatchBlock(*this, filterScope);
548  EHStack.popFilter();
549  }
550 }
551 
553  EnterCXXTryStmt(S);
554  EmitStmt(S.getTryBlock());
555  ExitCXXTryStmt(S);
556 }
557 
558 void CodeGenFunction::EnterCXXTryStmt(const CXXTryStmt &S, bool IsFnTryBlock) {
559  unsigned NumHandlers = S.getNumHandlers();
560  EHCatchScope *CatchScope = EHStack.pushCatch(NumHandlers);
561 
562  for (unsigned I = 0; I != NumHandlers; ++I) {
563  const CXXCatchStmt *C = S.getHandler(I);
564 
565  llvm::BasicBlock *Handler = createBasicBlock("catch");
566  if (C->getExceptionDecl()) {
567  // FIXME: Dropping the reference type on the type into makes it
568  // impossible to correctly implement catch-by-reference
569  // semantics for pointers. Unfortunately, this is what all
570  // existing compilers do, and it's not clear that the standard
571  // personality routine is capable of doing this right. See C++ DR 388:
572  // http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#388
573  Qualifiers CaughtTypeQuals;
574  QualType CaughtType = CGM.getContext().getUnqualifiedArrayType(
575  C->getCaughtType().getNonReferenceType(), CaughtTypeQuals);
576 
577  CatchTypeInfo TypeInfo{nullptr, 0};
578  if (CaughtType->isObjCObjectPointerType())
579  TypeInfo.RTTI = CGM.getObjCRuntime().GetEHType(CaughtType);
580  else
581  TypeInfo = CGM.getCXXABI().getAddrOfCXXCatchHandlerType(
582  CaughtType, C->getCaughtType());
583  CatchScope->setHandler(I, TypeInfo, Handler);
584  } else {
585  // No exception decl indicates '...', a catch-all.
586  CatchScope->setHandler(I, CGM.getCXXABI().getCatchAllTypeInfo(), Handler);
587  }
588  }
589 }
590 
591 llvm::BasicBlock *
593  if (EHPersonality::get(*this).usesFuncletPads())
594  return getFuncletEHDispatchBlock(si);
595 
596  // The dispatch block for the end of the scope chain is a block that
597  // just resumes unwinding.
598  if (si == EHStack.stable_end())
599  return getEHResumeBlock(true);
600 
601  // Otherwise, we should look at the actual scope.
602  EHScope &scope = *EHStack.find(si);
603 
604  llvm::BasicBlock *dispatchBlock = scope.getCachedEHDispatchBlock();
605  if (!dispatchBlock) {
606  switch (scope.getKind()) {
607  case EHScope::Catch: {
608  // Apply a special case to a single catch-all.
609  EHCatchScope &catchScope = cast<EHCatchScope>(scope);
610  if (catchScope.getNumHandlers() == 1 &&
611  catchScope.getHandler(0).isCatchAll()) {
612  dispatchBlock = catchScope.getHandler(0).Block;
613 
614  // Otherwise, make a dispatch block.
615  } else {
616  dispatchBlock = createBasicBlock("catch.dispatch");
617  }
618  break;
619  }
620 
621  case EHScope::Cleanup:
622  dispatchBlock = createBasicBlock("ehcleanup");
623  break;
624 
625  case EHScope::Filter:
626  dispatchBlock = createBasicBlock("filter.dispatch");
627  break;
628 
629  case EHScope::Terminate:
630  dispatchBlock = getTerminateHandler();
631  break;
632 
633  case EHScope::PadEnd:
634  llvm_unreachable("PadEnd unnecessary for Itanium!");
635  }
636  scope.setCachedEHDispatchBlock(dispatchBlock);
637  }
638  return dispatchBlock;
639 }
640 
641 llvm::BasicBlock *
643  // Returning nullptr indicates that the previous dispatch block should unwind
644  // to caller.
645  if (SI == EHStack.stable_end())
646  return nullptr;
647 
648  // Otherwise, we should look at the actual scope.
649  EHScope &EHS = *EHStack.find(SI);
650 
651  llvm::BasicBlock *DispatchBlock = EHS.getCachedEHDispatchBlock();
652  if (DispatchBlock)
653  return DispatchBlock;
654 
655  if (EHS.getKind() == EHScope::Terminate)
656  DispatchBlock = getTerminateFunclet();
657  else
658  DispatchBlock = createBasicBlock();
659  CGBuilderTy Builder(*this, DispatchBlock);
660 
661  switch (EHS.getKind()) {
662  case EHScope::Catch:
663  DispatchBlock->setName("catch.dispatch");
664  break;
665 
666  case EHScope::Cleanup:
667  DispatchBlock->setName("ehcleanup");
668  break;
669 
670  case EHScope::Filter:
671  llvm_unreachable("exception specifications not handled yet!");
672 
673  case EHScope::Terminate:
674  DispatchBlock->setName("terminate");
675  break;
676 
677  case EHScope::PadEnd:
678  llvm_unreachable("PadEnd dispatch block missing!");
679  }
680  EHS.setCachedEHDispatchBlock(DispatchBlock);
681  return DispatchBlock;
682 }
683 
684 /// Check whether this is a non-EH scope, i.e. a scope which doesn't
685 /// affect exception handling. Currently, the only non-EH scopes are
686 /// normal-only cleanup scopes.
687 static bool isNonEHScope(const EHScope &S) {
688  switch (S.getKind()) {
689  case EHScope::Cleanup:
690  return !cast<EHCleanupScope>(S).isEHCleanup();
691  case EHScope::Filter:
692  case EHScope::Catch:
693  case EHScope::Terminate:
694  case EHScope::PadEnd:
695  return false;
696  }
697 
698  llvm_unreachable("Invalid EHScope Kind!");
699 }
700 
702  assert(EHStack.requiresLandingPad());
703  assert(!EHStack.empty());
704 
705  // If exceptions are disabled and SEH is not in use, then there is no invoke
706  // destination. SEH "works" even if exceptions are off. In practice, this
707  // means that C++ destructors and other EH cleanups don't run, which is
708  // consistent with MSVC's behavior.
709  const LangOptions &LO = CGM.getLangOpts();
710  if (!LO.Exceptions) {
711  if (!LO.Borland && !LO.MicrosoftExt)
712  return nullptr;
713  if (!currentFunctionUsesSEHTry())
714  return nullptr;
715  }
716 
717  // CUDA device code doesn't have exceptions.
718  if (LO.CUDA && LO.CUDAIsDevice)
719  return nullptr;
720 
721  // Check the innermost scope for a cached landing pad. If this is
722  // a non-EH cleanup, we'll check enclosing scopes in EmitLandingPad.
723  llvm::BasicBlock *LP = EHStack.begin()->getCachedLandingPad();
724  if (LP) return LP;
725 
726  const EHPersonality &Personality = EHPersonality::get(*this);
727 
728  if (!CurFn->hasPersonalityFn())
729  CurFn->setPersonalityFn(getOpaquePersonalityFn(CGM, Personality));
730 
731  if (Personality.usesFuncletPads()) {
732  // We don't need separate landing pads in the funclet model.
733  LP = getEHDispatchBlock(EHStack.getInnermostEHScope());
734  } else {
735  // Build the landing pad for this scope.
736  LP = EmitLandingPad();
737  }
738 
739  assert(LP);
740 
741  // Cache the landing pad on the innermost scope. If this is a
742  // non-EH scope, cache the landing pad on the enclosing scope, too.
743  for (EHScopeStack::iterator ir = EHStack.begin(); true; ++ir) {
744  ir->setCachedLandingPad(LP);
745  if (!isNonEHScope(*ir)) break;
746  }
747 
748  return LP;
749 }
750 
751 llvm::BasicBlock *CodeGenFunction::EmitLandingPad() {
752  assert(EHStack.requiresLandingPad());
753 
754  EHScope &innermostEHScope = *EHStack.find(EHStack.getInnermostEHScope());
755  switch (innermostEHScope.getKind()) {
756  case EHScope::Terminate:
757  return getTerminateLandingPad();
758 
759  case EHScope::PadEnd:
760  llvm_unreachable("PadEnd unnecessary for Itanium!");
761 
762  case EHScope::Catch:
763  case EHScope::Cleanup:
764  case EHScope::Filter:
765  if (llvm::BasicBlock *lpad = innermostEHScope.getCachedLandingPad())
766  return lpad;
767  }
768 
769  // Save the current IR generation state.
770  CGBuilderTy::InsertPoint savedIP = Builder.saveAndClearIP();
771  auto DL = ApplyDebugLocation::CreateDefaultArtificial(*this, CurEHLocation);
772 
773  // Create and configure the landing pad.
774  llvm::BasicBlock *lpad = createBasicBlock("lpad");
775  EmitBlock(lpad);
776 
777  llvm::LandingPadInst *LPadInst =
778  Builder.CreateLandingPad(llvm::StructType::get(Int8PtrTy, Int32Ty), 0);
779 
780  llvm::Value *LPadExn = Builder.CreateExtractValue(LPadInst, 0);
781  Builder.CreateStore(LPadExn, getExceptionSlot());
782  llvm::Value *LPadSel = Builder.CreateExtractValue(LPadInst, 1);
783  Builder.CreateStore(LPadSel, getEHSelectorSlot());
784 
785  // Save the exception pointer. It's safe to use a single exception
786  // pointer per function because EH cleanups can never have nested
787  // try/catches.
788  // Build the landingpad instruction.
789 
790  // Accumulate all the handlers in scope.
791  bool hasCatchAll = false;
792  bool hasCleanup = false;
793  bool hasFilter = false;
794  SmallVector<llvm::Value*, 4> filterTypes;
795  llvm::SmallPtrSet<llvm::Value*, 4> catchTypes;
796  for (EHScopeStack::iterator I = EHStack.begin(), E = EHStack.end(); I != E;
797  ++I) {
798 
799  switch (I->getKind()) {
800  case EHScope::Cleanup:
801  // If we have a cleanup, remember that.
802  hasCleanup = (hasCleanup || cast<EHCleanupScope>(*I).isEHCleanup());
803  continue;
804 
805  case EHScope::Filter: {
806  assert(I.next() == EHStack.end() && "EH filter is not end of EH stack");
807  assert(!hasCatchAll && "EH filter reached after catch-all");
808 
809  // Filter scopes get added to the landingpad in weird ways.
810  EHFilterScope &filter = cast<EHFilterScope>(*I);
811  hasFilter = true;
812 
813  // Add all the filter values.
814  for (unsigned i = 0, e = filter.getNumFilters(); i != e; ++i)
815  filterTypes.push_back(filter.getFilter(i));
816  goto done;
817  }
818 
819  case EHScope::Terminate:
820  // Terminate scopes are basically catch-alls.
821  assert(!hasCatchAll);
822  hasCatchAll = true;
823  goto done;
824 
825  case EHScope::Catch:
826  break;
827 
828  case EHScope::PadEnd:
829  llvm_unreachable("PadEnd unnecessary for Itanium!");
830  }
831 
832  EHCatchScope &catchScope = cast<EHCatchScope>(*I);
833  for (unsigned hi = 0, he = catchScope.getNumHandlers(); hi != he; ++hi) {
834  EHCatchScope::Handler handler = catchScope.getHandler(hi);
835  assert(handler.Type.Flags == 0 &&
836  "landingpads do not support catch handler flags");
837 
838  // If this is a catch-all, register that and abort.
839  if (!handler.Type.RTTI) {
840  assert(!hasCatchAll);
841  hasCatchAll = true;
842  goto done;
843  }
844 
845  // Check whether we already have a handler for this type.
846  if (catchTypes.insert(handler.Type.RTTI).second)
847  // If not, add it directly to the landingpad.
848  LPadInst->addClause(handler.Type.RTTI);
849  }
850  }
851 
852  done:
853  // If we have a catch-all, add null to the landingpad.
854  assert(!(hasCatchAll && hasFilter));
855  if (hasCatchAll) {
856  LPadInst->addClause(getCatchAllValue(*this));
857 
858  // If we have an EH filter, we need to add those handlers in the
859  // right place in the landingpad, which is to say, at the end.
860  } else if (hasFilter) {
861  // Create a filter expression: a constant array indicating which filter
862  // types there are. The personality routine only lands here if the filter
863  // doesn't match.
865  llvm::ArrayType *AType =
866  llvm::ArrayType::get(!filterTypes.empty() ?
867  filterTypes[0]->getType() : Int8PtrTy,
868  filterTypes.size());
869 
870  for (unsigned i = 0, e = filterTypes.size(); i != e; ++i)
871  Filters.push_back(cast<llvm::Constant>(filterTypes[i]));
872  llvm::Constant *FilterArray = llvm::ConstantArray::get(AType, Filters);
873  LPadInst->addClause(FilterArray);
874 
875  // Also check whether we need a cleanup.
876  if (hasCleanup)
877  LPadInst->setCleanup(true);
878 
879  // Otherwise, signal that we at least have cleanups.
880  } else if (hasCleanup) {
881  LPadInst->setCleanup(true);
882  }
883 
884  assert((LPadInst->getNumClauses() > 0 || LPadInst->isCleanup()) &&
885  "landingpad instruction has no clauses!");
886 
887  // Tell the backend how to generate the landing pad.
888  Builder.CreateBr(getEHDispatchBlock(EHStack.getInnermostEHScope()));
889 
890  // Restore the old IR generation state.
891  Builder.restoreIP(savedIP);
892 
893  return lpad;
894 }
895 
896 static void emitCatchPadBlock(CodeGenFunction &CGF, EHCatchScope &CatchScope) {
897  llvm::BasicBlock *DispatchBlock = CatchScope.getCachedEHDispatchBlock();
898  assert(DispatchBlock);
899 
900  CGBuilderTy::InsertPoint SavedIP = CGF.Builder.saveIP();
901  CGF.EmitBlockAfterUses(DispatchBlock);
902 
903  llvm::Value *ParentPad = CGF.CurrentFuncletPad;
904  if (!ParentPad)
905  ParentPad = llvm::ConstantTokenNone::get(CGF.getLLVMContext());
906  llvm::BasicBlock *UnwindBB =
907  CGF.getEHDispatchBlock(CatchScope.getEnclosingEHScope());
908 
909  unsigned NumHandlers = CatchScope.getNumHandlers();
910  llvm::CatchSwitchInst *CatchSwitch =
911  CGF.Builder.CreateCatchSwitch(ParentPad, UnwindBB, NumHandlers);
912 
913  // Test against each of the exception types we claim to catch.
914  for (unsigned I = 0; I < NumHandlers; ++I) {
915  const EHCatchScope::Handler &Handler = CatchScope.getHandler(I);
916 
917  CatchTypeInfo TypeInfo = Handler.Type;
918  if (!TypeInfo.RTTI)
919  TypeInfo.RTTI = llvm::Constant::getNullValue(CGF.VoidPtrTy);
920 
921  CGF.Builder.SetInsertPoint(Handler.Block);
922 
923  if (EHPersonality::get(CGF).isMSVCXXPersonality()) {
924  CGF.Builder.CreateCatchPad(
925  CatchSwitch, {TypeInfo.RTTI, CGF.Builder.getInt32(TypeInfo.Flags),
926  llvm::Constant::getNullValue(CGF.VoidPtrTy)});
927  } else {
928  CGF.Builder.CreateCatchPad(CatchSwitch, {TypeInfo.RTTI});
929  }
930 
931  CatchSwitch->addHandler(Handler.Block);
932  }
933  CGF.Builder.restoreIP(SavedIP);
934 }
935 
936 // Wasm uses Windows-style EH instructions, but it merges all catch clauses into
937 // one big catchpad, within which we use Itanium's landingpad-style selector
938 // comparison instructions.
940  EHCatchScope &CatchScope) {
941  llvm::BasicBlock *DispatchBlock = CatchScope.getCachedEHDispatchBlock();
942  assert(DispatchBlock);
943 
944  CGBuilderTy::InsertPoint SavedIP = CGF.Builder.saveIP();
945  CGF.EmitBlockAfterUses(DispatchBlock);
946 
947  llvm::Value *ParentPad = CGF.CurrentFuncletPad;
948  if (!ParentPad)
949  ParentPad = llvm::ConstantTokenNone::get(CGF.getLLVMContext());
950  llvm::BasicBlock *UnwindBB =
951  CGF.getEHDispatchBlock(CatchScope.getEnclosingEHScope());
952 
953  unsigned NumHandlers = CatchScope.getNumHandlers();
954  llvm::CatchSwitchInst *CatchSwitch =
955  CGF.Builder.CreateCatchSwitch(ParentPad, UnwindBB, NumHandlers);
956 
957  // We don't use a landingpad instruction, so generate intrinsic calls to
958  // provide exception and selector values.
959  llvm::BasicBlock *WasmCatchStartBlock = CGF.createBasicBlock("catch.start");
960  CatchSwitch->addHandler(WasmCatchStartBlock);
961  CGF.EmitBlockAfterUses(WasmCatchStartBlock);
962 
963  // Create a catchpad instruction.
965  for (unsigned I = 0, E = NumHandlers; I < E; ++I) {
966  const EHCatchScope::Handler &Handler = CatchScope.getHandler(I);
967  CatchTypeInfo TypeInfo = Handler.Type;
968  if (!TypeInfo.RTTI)
969  TypeInfo.RTTI = llvm::Constant::getNullValue(CGF.VoidPtrTy);
970  CatchTypes.push_back(TypeInfo.RTTI);
971  }
972  auto *CPI = CGF.Builder.CreateCatchPad(CatchSwitch, CatchTypes);
973 
974  // Create calls to wasm.get.exception and wasm.get.ehselector intrinsics.
975  // Before they are lowered appropriately later, they provide values for the
976  // exception and selector.
977  llvm::Function *GetExnFn =
978  CGF.CGM.getIntrinsic(llvm::Intrinsic::wasm_get_exception);
979  llvm::Function *GetSelectorFn =
980  CGF.CGM.getIntrinsic(llvm::Intrinsic::wasm_get_ehselector);
981  llvm::CallInst *Exn = CGF.Builder.CreateCall(GetExnFn, CPI);
982  CGF.Builder.CreateStore(Exn, CGF.getExceptionSlot());
983  llvm::CallInst *Selector = CGF.Builder.CreateCall(GetSelectorFn, CPI);
984 
985  llvm::Function *TypeIDFn = CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_typeid_for);
986 
987  // If there's only a single catch-all, branch directly to its handler.
988  if (CatchScope.getNumHandlers() == 1 &&
989  CatchScope.getHandler(0).isCatchAll()) {
990  CGF.Builder.CreateBr(CatchScope.getHandler(0).Block);
991  CGF.Builder.restoreIP(SavedIP);
992  return;
993  }
994 
995  // Test against each of the exception types we claim to catch.
996  for (unsigned I = 0, E = NumHandlers;; ++I) {
997  assert(I < E && "ran off end of handlers!");
998  const EHCatchScope::Handler &Handler = CatchScope.getHandler(I);
999  CatchTypeInfo TypeInfo = Handler.Type;
1000  if (!TypeInfo.RTTI)
1001  TypeInfo.RTTI = llvm::Constant::getNullValue(CGF.VoidPtrTy);
1002 
1003  // Figure out the next block.
1004  llvm::BasicBlock *NextBlock;
1005 
1006  bool EmitNextBlock = false, NextIsEnd = false;
1007 
1008  // If this is the last handler, we're at the end, and the next block is a
1009  // block that contains a call to the rethrow function, so we can unwind to
1010  // the enclosing EH scope. The call itself will be generated later.
1011  if (I + 1 == E) {
1012  NextBlock = CGF.createBasicBlock("rethrow");
1013  EmitNextBlock = true;
1014  NextIsEnd = true;
1015 
1016  // If the next handler is a catch-all, we're at the end, and the
1017  // next block is that handler.
1018  } else if (CatchScope.getHandler(I + 1).isCatchAll()) {
1019  NextBlock = CatchScope.getHandler(I + 1).Block;
1020  NextIsEnd = true;
1021 
1022  // Otherwise, we're not at the end and we need a new block.
1023  } else {
1024  NextBlock = CGF.createBasicBlock("catch.fallthrough");
1025  EmitNextBlock = true;
1026  }
1027 
1028  // Figure out the catch type's index in the LSDA's type table.
1029  llvm::CallInst *TypeIndex = CGF.Builder.CreateCall(TypeIDFn, TypeInfo.RTTI);
1030  TypeIndex->setDoesNotThrow();
1031 
1032  llvm::Value *MatchesTypeIndex =
1033  CGF.Builder.CreateICmpEQ(Selector, TypeIndex, "matches");
1034  CGF.Builder.CreateCondBr(MatchesTypeIndex, Handler.Block, NextBlock);
1035 
1036  if (EmitNextBlock)
1037  CGF.EmitBlock(NextBlock);
1038  if (NextIsEnd)
1039  break;
1040  }
1041 
1042  CGF.Builder.restoreIP(SavedIP);
1043 }
1044 
1045 /// Emit the structure of the dispatch block for the given catch scope.
1046 /// It is an invariant that the dispatch block already exists.
1048  EHCatchScope &catchScope) {
1049  if (EHPersonality::get(CGF).isWasmPersonality())
1050  return emitWasmCatchPadBlock(CGF, catchScope);
1051  if (EHPersonality::get(CGF).usesFuncletPads())
1052  return emitCatchPadBlock(CGF, catchScope);
1053 
1054  llvm::BasicBlock *dispatchBlock = catchScope.getCachedEHDispatchBlock();
1055  assert(dispatchBlock);
1056 
1057  // If there's only a single catch-all, getEHDispatchBlock returned
1058  // that catch-all as the dispatch block.
1059  if (catchScope.getNumHandlers() == 1 &&
1060  catchScope.getHandler(0).isCatchAll()) {
1061  assert(dispatchBlock == catchScope.getHandler(0).Block);
1062  return;
1063  }
1064 
1065  CGBuilderTy::InsertPoint savedIP = CGF.Builder.saveIP();
1066  CGF.EmitBlockAfterUses(dispatchBlock);
1067 
1068  // Select the right handler.
1069  llvm::Function *llvm_eh_typeid_for =
1070  CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_typeid_for);
1071 
1072  // Load the selector value.
1073  llvm::Value *selector = CGF.getSelectorFromSlot();
1074 
1075  // Test against each of the exception types we claim to catch.
1076  for (unsigned i = 0, e = catchScope.getNumHandlers(); ; ++i) {
1077  assert(i < e && "ran off end of handlers!");
1078  const EHCatchScope::Handler &handler = catchScope.getHandler(i);
1079 
1080  llvm::Value *typeValue = handler.Type.RTTI;
1081  assert(handler.Type.Flags == 0 &&
1082  "landingpads do not support catch handler flags");
1083  assert(typeValue && "fell into catch-all case!");
1084  typeValue = CGF.Builder.CreateBitCast(typeValue, CGF.Int8PtrTy);
1085 
1086  // Figure out the next block.
1087  bool nextIsEnd;
1088  llvm::BasicBlock *nextBlock;
1089 
1090  // If this is the last handler, we're at the end, and the next
1091  // block is the block for the enclosing EH scope.
1092  if (i + 1 == e) {
1093  nextBlock = CGF.getEHDispatchBlock(catchScope.getEnclosingEHScope());
1094  nextIsEnd = true;
1095 
1096  // If the next handler is a catch-all, we're at the end, and the
1097  // next block is that handler.
1098  } else if (catchScope.getHandler(i+1).isCatchAll()) {
1099  nextBlock = catchScope.getHandler(i+1).Block;
1100  nextIsEnd = true;
1101 
1102  // Otherwise, we're not at the end and we need a new block.
1103  } else {
1104  nextBlock = CGF.createBasicBlock("catch.fallthrough");
1105  nextIsEnd = false;
1106  }
1107 
1108  // Figure out the catch type's index in the LSDA's type table.
1109  llvm::CallInst *typeIndex =
1110  CGF.Builder.CreateCall(llvm_eh_typeid_for, typeValue);
1111  typeIndex->setDoesNotThrow();
1112 
1113  llvm::Value *matchesTypeIndex =
1114  CGF.Builder.CreateICmpEQ(selector, typeIndex, "matches");
1115  CGF.Builder.CreateCondBr(matchesTypeIndex, handler.Block, nextBlock);
1116 
1117  // If the next handler is a catch-all, we're completely done.
1118  if (nextIsEnd) {
1119  CGF.Builder.restoreIP(savedIP);
1120  return;
1121  }
1122  // Otherwise we need to emit and continue at that block.
1123  CGF.EmitBlock(nextBlock);
1124  }
1125 }
1126 
1128  EHCatchScope &catchScope = cast<EHCatchScope>(*EHStack.begin());
1129  if (catchScope.hasEHBranches())
1130  emitCatchDispatchBlock(*this, catchScope);
1131  EHStack.popCatch();
1132 }
1133 
1134 void CodeGenFunction::ExitCXXTryStmt(const CXXTryStmt &S, bool IsFnTryBlock) {
1135  unsigned NumHandlers = S.getNumHandlers();
1136  EHCatchScope &CatchScope = cast<EHCatchScope>(*EHStack.begin());
1137  assert(CatchScope.getNumHandlers() == NumHandlers);
1138  llvm::BasicBlock *DispatchBlock = CatchScope.getCachedEHDispatchBlock();
1139 
1140  // If the catch was not required, bail out now.
1141  if (!CatchScope.hasEHBranches()) {
1142  CatchScope.clearHandlerBlocks();
1143  EHStack.popCatch();
1144  return;
1145  }
1146 
1147  // Emit the structure of the EH dispatch for this catch.
1148  emitCatchDispatchBlock(*this, CatchScope);
1149 
1150  // Copy the handler blocks off before we pop the EH stack. Emitting
1151  // the handlers might scribble on this memory.
1153  CatchScope.begin(), CatchScope.begin() + NumHandlers);
1154 
1155  EHStack.popCatch();
1156 
1157  // The fall-through block.
1158  llvm::BasicBlock *ContBB = createBasicBlock("try.cont");
1159 
1160  // We just emitted the body of the try; jump to the continue block.
1161  if (HaveInsertPoint())
1162  Builder.CreateBr(ContBB);
1163 
1164  // Determine if we need an implicit rethrow for all these catch handlers;
1165  // see the comment below.
1166  bool doImplicitRethrow = false;
1167  if (IsFnTryBlock)
1168  doImplicitRethrow = isa<CXXDestructorDecl>(CurCodeDecl) ||
1169  isa<CXXConstructorDecl>(CurCodeDecl);
1170 
1171  // Wasm uses Windows-style EH instructions, but merges all catch clauses into
1172  // one big catchpad. So we save the old funclet pad here before we traverse
1173  // each catch handler.
1174  SaveAndRestore<llvm::Instruction *> RestoreCurrentFuncletPad(
1175  CurrentFuncletPad);
1176  llvm::BasicBlock *WasmCatchStartBlock = nullptr;
1177  if (EHPersonality::get(*this).isWasmPersonality()) {
1178  auto *CatchSwitch =
1179  cast<llvm::CatchSwitchInst>(DispatchBlock->getFirstNonPHI());
1180  WasmCatchStartBlock = CatchSwitch->hasUnwindDest()
1181  ? CatchSwitch->getSuccessor(1)
1182  : CatchSwitch->getSuccessor(0);
1183  auto *CPI = cast<llvm::CatchPadInst>(WasmCatchStartBlock->getFirstNonPHI());
1184  CurrentFuncletPad = CPI;
1185  }
1186 
1187  // Perversely, we emit the handlers backwards precisely because we
1188  // want them to appear in source order. In all of these cases, the
1189  // catch block will have exactly one predecessor, which will be a
1190  // particular block in the catch dispatch. However, in the case of
1191  // a catch-all, one of the dispatch blocks will branch to two
1192  // different handlers, and EmitBlockAfterUses will cause the second
1193  // handler to be moved before the first.
1194  bool HasCatchAll = false;
1195  for (unsigned I = NumHandlers; I != 0; --I) {
1196  HasCatchAll |= Handlers[I - 1].isCatchAll();
1197  llvm::BasicBlock *CatchBlock = Handlers[I-1].Block;
1198  EmitBlockAfterUses(CatchBlock);
1199 
1200  // Catch the exception if this isn't a catch-all.
1201  const CXXCatchStmt *C = S.getHandler(I-1);
1202 
1203  // Enter a cleanup scope, including the catch variable and the
1204  // end-catch.
1205  RunCleanupsScope CatchScope(*this);
1206 
1207  // Initialize the catch variable and set up the cleanups.
1208  SaveAndRestore<llvm::Instruction *> RestoreCurrentFuncletPad(
1209  CurrentFuncletPad);
1210  CGM.getCXXABI().emitBeginCatch(*this, C);
1211 
1212  // Emit the PGO counter increment.
1213  incrementProfileCounter(C);
1214 
1215  // Perform the body of the catch.
1216  EmitStmt(C->getHandlerBlock());
1217 
1218  // [except.handle]p11:
1219  // The currently handled exception is rethrown if control
1220  // reaches the end of a handler of the function-try-block of a
1221  // constructor or destructor.
1222 
1223  // It is important that we only do this on fallthrough and not on
1224  // return. Note that it's illegal to put a return in a
1225  // constructor function-try-block's catch handler (p14), so this
1226  // really only applies to destructors.
1227  if (doImplicitRethrow && HaveInsertPoint()) {
1228  CGM.getCXXABI().emitRethrow(*this, /*isNoReturn*/false);
1229  Builder.CreateUnreachable();
1230  Builder.ClearInsertionPoint();
1231  }
1232 
1233  // Fall out through the catch cleanups.
1234  CatchScope.ForceCleanup();
1235 
1236  // Branch out of the try.
1237  if (HaveInsertPoint())
1238  Builder.CreateBr(ContBB);
1239  }
1240 
1241  // Because in wasm we merge all catch clauses into one big catchpad, in case
1242  // none of the types in catch handlers matches after we test against each of
1243  // them, we should unwind to the next EH enclosing scope. We generate a call
1244  // to rethrow function here to do that.
1245  if (EHPersonality::get(*this).isWasmPersonality() && !HasCatchAll) {
1246  assert(WasmCatchStartBlock);
1247  // Navigate for the "rethrow" block we created in emitWasmCatchPadBlock().
1248  // Wasm uses landingpad-style conditional branches to compare selectors, so
1249  // we follow the false destination for each of the cond branches to reach
1250  // the rethrow block.
1251  llvm::BasicBlock *RethrowBlock = WasmCatchStartBlock;
1252  while (llvm::Instruction *TI = RethrowBlock->getTerminator()) {
1253  auto *BI = cast<llvm::BranchInst>(TI);
1254  assert(BI->isConditional());
1255  RethrowBlock = BI->getSuccessor(1);
1256  }
1257  assert(RethrowBlock != WasmCatchStartBlock && RethrowBlock->empty());
1258  Builder.SetInsertPoint(RethrowBlock);
1259  llvm::Function *RethrowInCatchFn =
1260  CGM.getIntrinsic(llvm::Intrinsic::wasm_rethrow_in_catch);
1261  EmitNoreturnRuntimeCallOrInvoke(RethrowInCatchFn, {});
1262  }
1263 
1264  EmitBlock(ContBB);
1265  incrementProfileCounter(&S);
1266 }
1267 
1268 namespace {
1269  struct CallEndCatchForFinally final : EHScopeStack::Cleanup {
1270  llvm::Value *ForEHVar;
1271  llvm::FunctionCallee EndCatchFn;
1272  CallEndCatchForFinally(llvm::Value *ForEHVar,
1273  llvm::FunctionCallee EndCatchFn)
1274  : ForEHVar(ForEHVar), EndCatchFn(EndCatchFn) {}
1275 
1276  void Emit(CodeGenFunction &CGF, Flags flags) override {
1277  llvm::BasicBlock *EndCatchBB = CGF.createBasicBlock("finally.endcatch");
1278  llvm::BasicBlock *CleanupContBB =
1279  CGF.createBasicBlock("finally.cleanup.cont");
1280 
1281  llvm::Value *ShouldEndCatch =
1282  CGF.Builder.CreateFlagLoad(ForEHVar, "finally.endcatch");
1283  CGF.Builder.CreateCondBr(ShouldEndCatch, EndCatchBB, CleanupContBB);
1284  CGF.EmitBlock(EndCatchBB);
1285  CGF.EmitRuntimeCallOrInvoke(EndCatchFn); // catch-all, so might throw
1286  CGF.EmitBlock(CleanupContBB);
1287  }
1288  };
1289 
1290  struct PerformFinally final : EHScopeStack::Cleanup {
1291  const Stmt *Body;
1292  llvm::Value *ForEHVar;
1293  llvm::FunctionCallee EndCatchFn;
1294  llvm::FunctionCallee RethrowFn;
1295  llvm::Value *SavedExnVar;
1296 
1297  PerformFinally(const Stmt *Body, llvm::Value *ForEHVar,
1298  llvm::FunctionCallee EndCatchFn,
1299  llvm::FunctionCallee RethrowFn, llvm::Value *SavedExnVar)
1300  : Body(Body), ForEHVar(ForEHVar), EndCatchFn(EndCatchFn),
1301  RethrowFn(RethrowFn), SavedExnVar(SavedExnVar) {}
1302 
1303  void Emit(CodeGenFunction &CGF, Flags flags) override {
1304  // Enter a cleanup to call the end-catch function if one was provided.
1305  if (EndCatchFn)
1306  CGF.EHStack.pushCleanup<CallEndCatchForFinally>(NormalAndEHCleanup,
1307  ForEHVar, EndCatchFn);
1308 
1309  // Save the current cleanup destination in case there are
1310  // cleanups in the finally block.
1311  llvm::Value *SavedCleanupDest =
1313  "cleanup.dest.saved");
1314 
1315  // Emit the finally block.
1316  CGF.EmitStmt(Body);
1317 
1318  // If the end of the finally is reachable, check whether this was
1319  // for EH. If so, rethrow.
1320  if (CGF.HaveInsertPoint()) {
1321  llvm::BasicBlock *RethrowBB = CGF.createBasicBlock("finally.rethrow");
1322  llvm::BasicBlock *ContBB = CGF.createBasicBlock("finally.cont");
1323 
1324  llvm::Value *ShouldRethrow =
1325  CGF.Builder.CreateFlagLoad(ForEHVar, "finally.shouldthrow");
1326  CGF.Builder.CreateCondBr(ShouldRethrow, RethrowBB, ContBB);
1327 
1328  CGF.EmitBlock(RethrowBB);
1329  if (SavedExnVar) {
1330  CGF.EmitRuntimeCallOrInvoke(RethrowFn,
1331  CGF.Builder.CreateAlignedLoad(SavedExnVar, CGF.getPointerAlign()));
1332  } else {
1333  CGF.EmitRuntimeCallOrInvoke(RethrowFn);
1334  }
1335  CGF.Builder.CreateUnreachable();
1336 
1337  CGF.EmitBlock(ContBB);
1338 
1339  // Restore the cleanup destination.
1340  CGF.Builder.CreateStore(SavedCleanupDest,
1341  CGF.getNormalCleanupDestSlot());
1342  }
1343 
1344  // Leave the end-catch cleanup. As an optimization, pretend that
1345  // the fallthrough path was inaccessible; we've dynamically proven
1346  // that we're not in the EH case along that path.
1347  if (EndCatchFn) {
1348  CGBuilderTy::InsertPoint SavedIP = CGF.Builder.saveAndClearIP();
1349  CGF.PopCleanupBlock();
1350  CGF.Builder.restoreIP(SavedIP);
1351  }
1352 
1353  // Now make sure we actually have an insertion point or the
1354  // cleanup gods will hate us.
1355  CGF.EnsureInsertPoint();
1356  }
1357  };
1358 } // end anonymous namespace
1359 
1360 /// Enters a finally block for an implementation using zero-cost
1361 /// exceptions. This is mostly general, but hard-codes some
1362 /// language/ABI-specific behavior in the catch-all sections.
1364  llvm::FunctionCallee beginCatchFn,
1365  llvm::FunctionCallee endCatchFn,
1366  llvm::FunctionCallee rethrowFn) {
1367  assert((!!beginCatchFn) == (!!endCatchFn) &&
1368  "begin/end catch functions not paired");
1369  assert(rethrowFn && "rethrow function is required");
1370 
1371  BeginCatchFn = beginCatchFn;
1372 
1373  // The rethrow function has one of the following two types:
1374  // void (*)()
1375  // void (*)(void*)
1376  // In the latter case we need to pass it the exception object.
1377  // But we can't use the exception slot because the @finally might
1378  // have a landing pad (which would overwrite the exception slot).
1379  llvm::FunctionType *rethrowFnTy = rethrowFn.getFunctionType();
1380  SavedExnVar = nullptr;
1381  if (rethrowFnTy->getNumParams())
1382  SavedExnVar = CGF.CreateTempAlloca(CGF.Int8PtrTy, "finally.exn");
1383 
1384  // A finally block is a statement which must be executed on any edge
1385  // out of a given scope. Unlike a cleanup, the finally block may
1386  // contain arbitrary control flow leading out of itself. In
1387  // addition, finally blocks should always be executed, even if there
1388  // are no catch handlers higher on the stack. Therefore, we
1389  // surround the protected scope with a combination of a normal
1390  // cleanup (to catch attempts to break out of the block via normal
1391  // control flow) and an EH catch-all (semantically "outside" any try
1392  // statement to which the finally block might have been attached).
1393  // The finally block itself is generated in the context of a cleanup
1394  // which conditionally leaves the catch-all.
1395 
1396  // Jump destination for performing the finally block on an exception
1397  // edge. We'll never actually reach this block, so unreachable is
1398  // fine.
1399  RethrowDest = CGF.getJumpDestInCurrentScope(CGF.getUnreachableBlock());
1400 
1401  // Whether the finally block is being executed for EH purposes.
1402  ForEHVar = CGF.CreateTempAlloca(CGF.Builder.getInt1Ty(), "finally.for-eh");
1403  CGF.Builder.CreateFlagStore(false, ForEHVar);
1404 
1405  // Enter a normal cleanup which will perform the @finally block.
1406  CGF.EHStack.pushCleanup<PerformFinally>(NormalCleanup, body,
1407  ForEHVar, endCatchFn,
1408  rethrowFn, SavedExnVar);
1409 
1410  // Enter a catch-all scope.
1411  llvm::BasicBlock *catchBB = CGF.createBasicBlock("finally.catchall");
1412  EHCatchScope *catchScope = CGF.EHStack.pushCatch(1);
1413  catchScope->setCatchAllHandler(0, catchBB);
1414 }
1415 
1417  // Leave the finally catch-all.
1418  EHCatchScope &catchScope = cast<EHCatchScope>(*CGF.EHStack.begin());
1419  llvm::BasicBlock *catchBB = catchScope.getHandler(0).Block;
1420 
1421  CGF.popCatchScope();
1422 
1423  // If there are any references to the catch-all block, emit it.
1424  if (catchBB->use_empty()) {
1425  delete catchBB;
1426  } else {
1427  CGBuilderTy::InsertPoint savedIP = CGF.Builder.saveAndClearIP();
1428  CGF.EmitBlock(catchBB);
1429 
1430  llvm::Value *exn = nullptr;
1431 
1432  // If there's a begin-catch function, call it.
1433  if (BeginCatchFn) {
1434  exn = CGF.getExceptionFromSlot();
1435  CGF.EmitNounwindRuntimeCall(BeginCatchFn, exn);
1436  }
1437 
1438  // If we need to remember the exception pointer to rethrow later, do so.
1439  if (SavedExnVar) {
1440  if (!exn) exn = CGF.getExceptionFromSlot();
1441  CGF.Builder.CreateAlignedStore(exn, SavedExnVar, CGF.getPointerAlign());
1442  }
1443 
1444  // Tell the cleanups in the finally block that we're do this for EH.
1445  CGF.Builder.CreateFlagStore(true, ForEHVar);
1446 
1447  // Thread a jump through the finally cleanup.
1448  CGF.EmitBranchThroughCleanup(RethrowDest);
1449 
1450  CGF.Builder.restoreIP(savedIP);
1451  }
1452 
1453  // Finally, leave the @finally cleanup.
1454  CGF.PopCleanupBlock();
1455 }
1456 
1458  if (TerminateLandingPad)
1459  return TerminateLandingPad;
1460 
1461  CGBuilderTy::InsertPoint SavedIP = Builder.saveAndClearIP();
1462 
1463  // This will get inserted at the end of the function.
1464  TerminateLandingPad = createBasicBlock("terminate.lpad");
1465  Builder.SetInsertPoint(TerminateLandingPad);
1466 
1467  // Tell the backend that this is a landing pad.
1468  const EHPersonality &Personality = EHPersonality::get(*this);
1469 
1470  if (!CurFn->hasPersonalityFn())
1471  CurFn->setPersonalityFn(getOpaquePersonalityFn(CGM, Personality));
1472 
1473  llvm::LandingPadInst *LPadInst =
1474  Builder.CreateLandingPad(llvm::StructType::get(Int8PtrTy, Int32Ty), 0);
1475  LPadInst->addClause(getCatchAllValue(*this));
1476 
1477  llvm::Value *Exn = nullptr;
1478  if (getLangOpts().CPlusPlus)
1479  Exn = Builder.CreateExtractValue(LPadInst, 0);
1480  llvm::CallInst *terminateCall =
1481  CGM.getCXXABI().emitTerminateForUnexpectedException(*this, Exn);
1482  terminateCall->setDoesNotReturn();
1483  Builder.CreateUnreachable();
1484 
1485  // Restore the saved insertion state.
1486  Builder.restoreIP(SavedIP);
1487 
1488  return TerminateLandingPad;
1489 }
1490 
1492  if (TerminateHandler)
1493  return TerminateHandler;
1494 
1495  // Set up the terminate handler. This block is inserted at the very
1496  // end of the function by FinishFunction.
1497  TerminateHandler = createBasicBlock("terminate.handler");
1498  CGBuilderTy::InsertPoint SavedIP = Builder.saveAndClearIP();
1499  Builder.SetInsertPoint(TerminateHandler);
1500 
1501  llvm::Value *Exn = nullptr;
1502  if (getLangOpts().CPlusPlus)
1503  Exn = getExceptionFromSlot();
1504  llvm::CallInst *terminateCall =
1505  CGM.getCXXABI().emitTerminateForUnexpectedException(*this, Exn);
1506  terminateCall->setDoesNotReturn();
1507  Builder.CreateUnreachable();
1508 
1509  // Restore the saved insertion state.
1510  Builder.restoreIP(SavedIP);
1511 
1512  return TerminateHandler;
1513 }
1514 
1516  assert(EHPersonality::get(*this).usesFuncletPads() &&
1517  "use getTerminateLandingPad for non-funclet EH");
1518 
1519  llvm::BasicBlock *&TerminateFunclet = TerminateFunclets[CurrentFuncletPad];
1520  if (TerminateFunclet)
1521  return TerminateFunclet;
1522 
1523  CGBuilderTy::InsertPoint SavedIP = Builder.saveAndClearIP();
1524 
1525  // Set up the terminate handler. This block is inserted at the very
1526  // end of the function by FinishFunction.
1527  TerminateFunclet = createBasicBlock("terminate.handler");
1528  Builder.SetInsertPoint(TerminateFunclet);
1529 
1530  // Create the cleanuppad using the current parent pad as its token. Use 'none'
1531  // if this is a top-level terminate scope, which is the common case.
1532  SaveAndRestore<llvm::Instruction *> RestoreCurrentFuncletPad(
1533  CurrentFuncletPad);
1534  llvm::Value *ParentPad = CurrentFuncletPad;
1535  if (!ParentPad)
1536  ParentPad = llvm::ConstantTokenNone::get(CGM.getLLVMContext());
1537  CurrentFuncletPad = Builder.CreateCleanupPad(ParentPad);
1538 
1539  // Emit the __std_terminate call.
1540  llvm::Value *Exn = nullptr;
1541  // In case of wasm personality, we need to pass the exception value to
1542  // __clang_call_terminate function.
1543  if (getLangOpts().CPlusPlus &&
1545  llvm::Function *GetExnFn =
1546  CGM.getIntrinsic(llvm::Intrinsic::wasm_get_exception);
1547  Exn = Builder.CreateCall(GetExnFn, CurrentFuncletPad);
1548  }
1549  llvm::CallInst *terminateCall =
1550  CGM.getCXXABI().emitTerminateForUnexpectedException(*this, Exn);
1551  terminateCall->setDoesNotReturn();
1552  Builder.CreateUnreachable();
1553 
1554  // Restore the saved insertion state.
1555  Builder.restoreIP(SavedIP);
1556 
1557  return TerminateFunclet;
1558 }
1559 
1560 llvm::BasicBlock *CodeGenFunction::getEHResumeBlock(bool isCleanup) {
1561  if (EHResumeBlock) return EHResumeBlock;
1562 
1563  CGBuilderTy::InsertPoint SavedIP = Builder.saveIP();
1564 
1565  // We emit a jump to a notional label at the outermost unwind state.
1566  EHResumeBlock = createBasicBlock("eh.resume");
1567  Builder.SetInsertPoint(EHResumeBlock);
1568 
1569  const EHPersonality &Personality = EHPersonality::get(*this);
1570 
1571  // This can always be a call because we necessarily didn't find
1572  // anything on the EH stack which needs our help.
1573  const char *RethrowName = Personality.CatchallRethrowFn;
1574  if (RethrowName != nullptr && !isCleanup) {
1575  EmitRuntimeCall(getCatchallRethrowFn(CGM, RethrowName),
1576  getExceptionFromSlot())->setDoesNotReturn();
1577  Builder.CreateUnreachable();
1578  Builder.restoreIP(SavedIP);
1579  return EHResumeBlock;
1580  }
1581 
1582  // Recreate the landingpad's return value for the 'resume' instruction.
1583  llvm::Value *Exn = getExceptionFromSlot();
1584  llvm::Value *Sel = getSelectorFromSlot();
1585 
1586  llvm::Type *LPadType = llvm::StructType::get(Exn->getType(), Sel->getType());
1587  llvm::Value *LPadVal = llvm::UndefValue::get(LPadType);
1588  LPadVal = Builder.CreateInsertValue(LPadVal, Exn, 0, "lpad.val");
1589  LPadVal = Builder.CreateInsertValue(LPadVal, Sel, 1, "lpad.val");
1590 
1591  Builder.CreateResume(LPadVal);
1592  Builder.restoreIP(SavedIP);
1593  return EHResumeBlock;
1594 }
1595 
1597  EnterSEHTryStmt(S);
1598  {
1599  JumpDest TryExit = getJumpDestInCurrentScope("__try.__leave");
1600 
1601  SEHTryEpilogueStack.push_back(&TryExit);
1602  EmitStmt(S.getTryBlock());
1603  SEHTryEpilogueStack.pop_back();
1604 
1605  if (!TryExit.getBlock()->use_empty())
1606  EmitBlock(TryExit.getBlock(), /*IsFinished=*/true);
1607  else
1608  delete TryExit.getBlock();
1609  }
1610  ExitSEHTryStmt(S);
1611 }
1612 
1613 namespace {
1614 struct PerformSEHFinally final : EHScopeStack::Cleanup {
1615  llvm::Function *OutlinedFinally;
1616  PerformSEHFinally(llvm::Function *OutlinedFinally)
1617  : OutlinedFinally(OutlinedFinally) {}
1618 
1619  void Emit(CodeGenFunction &CGF, Flags F) override {
1620  ASTContext &Context = CGF.getContext();
1621  CodeGenModule &CGM = CGF.CGM;
1622 
1623  CallArgList Args;
1624 
1625  // Compute the two argument values.
1626  QualType ArgTys[2] = {Context.UnsignedCharTy, Context.VoidPtrTy};
1627  llvm::Value *FP = nullptr;
1628  // If CFG.IsOutlinedSEHHelper is true, then we are within a finally block.
1629  if (CGF.IsOutlinedSEHHelper) {
1630  FP = &CGF.CurFn->arg_begin()[1];
1631  } else {
1632  llvm::Function *LocalAddrFn =
1633  CGM.getIntrinsic(llvm::Intrinsic::localaddress);
1634  FP = CGF.Builder.CreateCall(LocalAddrFn);
1635  }
1636 
1637  llvm::Value *IsForEH =
1638  llvm::ConstantInt::get(CGF.ConvertType(ArgTys[0]), F.isForEHCleanup());
1639  Args.add(RValue::get(IsForEH), ArgTys[0]);
1640  Args.add(RValue::get(FP), ArgTys[1]);
1641 
1642  // Arrange a two-arg function info and type.
1643  const CGFunctionInfo &FnInfo =
1644  CGM.getTypes().arrangeBuiltinFunctionCall(Context.VoidTy, Args);
1645 
1646  auto Callee = CGCallee::forDirect(OutlinedFinally);
1647  CGF.EmitCall(FnInfo, Callee, ReturnValueSlot(), Args);
1648  }
1649 };
1650 } // end anonymous namespace
1651 
1652 namespace {
1653 /// Find all local variable captures in the statement.
1654 struct CaptureFinder : ConstStmtVisitor<CaptureFinder> {
1655  CodeGenFunction &ParentCGF;
1656  const VarDecl *ParentThis;
1658  Address SEHCodeSlot = Address::invalid();
1659  CaptureFinder(CodeGenFunction &ParentCGF, const VarDecl *ParentThis)
1660  : ParentCGF(ParentCGF), ParentThis(ParentThis) {}
1661 
1662  // Return true if we need to do any capturing work.
1663  bool foundCaptures() {
1664  return !Captures.empty() || SEHCodeSlot.isValid();
1665  }
1666 
1667  void Visit(const Stmt *S) {
1668  // See if this is a capture, then recurse.
1670  for (const Stmt *Child : S->children())
1671  if (Child)
1672  Visit(Child);
1673  }
1674 
1675  void VisitDeclRefExpr(const DeclRefExpr *E) {
1676  // If this is already a capture, just make sure we capture 'this'.
1678  Captures.insert(ParentThis);
1679  return;
1680  }
1681 
1682  const auto *D = dyn_cast<VarDecl>(E->getDecl());
1683  if (D && D->isLocalVarDeclOrParm() && D->hasLocalStorage())
1684  Captures.insert(D);
1685  }
1686 
1687  void VisitCXXThisExpr(const CXXThisExpr *E) {
1688  Captures.insert(ParentThis);
1689  }
1690 
1691  void VisitCallExpr(const CallExpr *E) {
1692  // We only need to add parent frame allocations for these builtins in x86.
1693  if (ParentCGF.getTarget().getTriple().getArch() != llvm::Triple::x86)
1694  return;
1695 
1696  unsigned ID = E->getBuiltinCallee();
1697  switch (ID) {
1698  case Builtin::BI__exception_code:
1699  case Builtin::BI_exception_code:
1700  // This is the simple case where we are the outermost finally. All we
1701  // have to do here is make sure we escape this and recover it in the
1702  // outlined handler.
1703  if (!SEHCodeSlot.isValid())
1704  SEHCodeSlot = ParentCGF.SEHCodeSlotStack.back();
1705  break;
1706  }
1707  }
1708 };
1709 } // end anonymous namespace
1710 
1712  Address ParentVar,
1713  llvm::Value *ParentFP) {
1714  llvm::CallInst *RecoverCall = nullptr;
1715  CGBuilderTy Builder(*this, AllocaInsertPt);
1716  if (auto *ParentAlloca = dyn_cast<llvm::AllocaInst>(ParentVar.getPointer())) {
1717  // Mark the variable escaped if nobody else referenced it and compute the
1718  // localescape index.
1719  auto InsertPair = ParentCGF.EscapedLocals.insert(
1720  std::make_pair(ParentAlloca, ParentCGF.EscapedLocals.size()));
1721  int FrameEscapeIdx = InsertPair.first->second;
1722  // call i8* @llvm.localrecover(i8* bitcast(@parentFn), i8* %fp, i32 N)
1723  llvm::Function *FrameRecoverFn = llvm::Intrinsic::getDeclaration(
1724  &CGM.getModule(), llvm::Intrinsic::localrecover);
1725  llvm::Constant *ParentI8Fn =
1726  llvm::ConstantExpr::getBitCast(ParentCGF.CurFn, Int8PtrTy);
1727  RecoverCall = Builder.CreateCall(
1728  FrameRecoverFn, {ParentI8Fn, ParentFP,
1729  llvm::ConstantInt::get(Int32Ty, FrameEscapeIdx)});
1730 
1731  } else {
1732  // If the parent didn't have an alloca, we're doing some nested outlining.
1733  // Just clone the existing localrecover call, but tweak the FP argument to
1734  // use our FP value. All other arguments are constants.
1735  auto *ParentRecover =
1736  cast<llvm::IntrinsicInst>(ParentVar.getPointer()->stripPointerCasts());
1737  assert(ParentRecover->getIntrinsicID() == llvm::Intrinsic::localrecover &&
1738  "expected alloca or localrecover in parent LocalDeclMap");
1739  RecoverCall = cast<llvm::CallInst>(ParentRecover->clone());
1740  RecoverCall->setArgOperand(1, ParentFP);
1741  RecoverCall->insertBefore(AllocaInsertPt);
1742  }
1743 
1744  // Bitcast the variable, rename it, and insert it in the local decl map.
1745  llvm::Value *ChildVar =
1746  Builder.CreateBitCast(RecoverCall, ParentVar.getType());
1747  ChildVar->setName(ParentVar.getName());
1748  return Address(ChildVar, ParentVar.getAlignment());
1749 }
1750 
1752  const Stmt *OutlinedStmt,
1753  bool IsFilter) {
1754  // Find all captures in the Stmt.
1755  CaptureFinder Finder(ParentCGF, ParentCGF.CXXABIThisDecl);
1756  Finder.Visit(OutlinedStmt);
1757 
1758  // We can exit early on x86_64 when there are no captures. We just have to
1759  // save the exception code in filters so that __exception_code() works.
1760  if (!Finder.foundCaptures() &&
1761  CGM.getTarget().getTriple().getArch() != llvm::Triple::x86) {
1762  if (IsFilter)
1763  EmitSEHExceptionCodeSave(ParentCGF, nullptr, nullptr);
1764  return;
1765  }
1766 
1767  llvm::Value *EntryFP = nullptr;
1768  CGBuilderTy Builder(CGM, AllocaInsertPt);
1769  if (IsFilter && CGM.getTarget().getTriple().getArch() == llvm::Triple::x86) {
1770  // 32-bit SEH filters need to be careful about FP recovery. The end of the
1771  // EH registration is passed in as the EBP physical register. We can
1772  // recover that with llvm.frameaddress(1).
1773  EntryFP = Builder.CreateCall(
1774  CGM.getIntrinsic(llvm::Intrinsic::frameaddress, AllocaInt8PtrTy),
1775  {Builder.getInt32(1)});
1776  } else {
1777  // Otherwise, for x64 and 32-bit finally functions, the parent FP is the
1778  // second parameter.
1779  auto AI = CurFn->arg_begin();
1780  ++AI;
1781  EntryFP = &*AI;
1782  }
1783 
1784  llvm::Value *ParentFP = EntryFP;
1785  if (IsFilter) {
1786  // Given whatever FP the runtime provided us in EntryFP, recover the true
1787  // frame pointer of the parent function. We only need to do this in filters,
1788  // since finally funclets recover the parent FP for us.
1789  llvm::Function *RecoverFPIntrin =
1790  CGM.getIntrinsic(llvm::Intrinsic::eh_recoverfp);
1791  llvm::Constant *ParentI8Fn =
1792  llvm::ConstantExpr::getBitCast(ParentCGF.CurFn, Int8PtrTy);
1793  ParentFP = Builder.CreateCall(RecoverFPIntrin, {ParentI8Fn, EntryFP});
1794  }
1795 
1796  // Create llvm.localrecover calls for all captures.
1797  for (const VarDecl *VD : Finder.Captures) {
1798  if (isa<ImplicitParamDecl>(VD)) {
1799  CGM.ErrorUnsupported(VD, "'this' captured by SEH");
1800  CXXThisValue = llvm::UndefValue::get(ConvertTypeForMem(VD->getType()));
1801  continue;
1802  }
1803  if (VD->getType()->isVariablyModifiedType()) {
1804  CGM.ErrorUnsupported(VD, "VLA captured by SEH");
1805  continue;
1806  }
1807  assert((isa<ImplicitParamDecl>(VD) || VD->isLocalVarDeclOrParm()) &&
1808  "captured non-local variable");
1809 
1810  // If this decl hasn't been declared yet, it will be declared in the
1811  // OutlinedStmt.
1812  auto I = ParentCGF.LocalDeclMap.find(VD);
1813  if (I == ParentCGF.LocalDeclMap.end())
1814  continue;
1815 
1816  Address ParentVar = I->second;
1817  setAddrOfLocalVar(
1818  VD, recoverAddrOfEscapedLocal(ParentCGF, ParentVar, ParentFP));
1819  }
1820 
1821  if (Finder.SEHCodeSlot.isValid()) {
1822  SEHCodeSlotStack.push_back(
1823  recoverAddrOfEscapedLocal(ParentCGF, Finder.SEHCodeSlot, ParentFP));
1824  }
1825 
1826  if (IsFilter)
1827  EmitSEHExceptionCodeSave(ParentCGF, ParentFP, EntryFP);
1828 }
1829 
1830 /// Arrange a function prototype that can be called by Windows exception
1831 /// handling personalities. On Win64, the prototype looks like:
1832 /// RetTy func(void *EHPtrs, void *ParentFP);
1834  bool IsFilter,
1835  const Stmt *OutlinedStmt) {
1836  SourceLocation StartLoc = OutlinedStmt->getBeginLoc();
1837 
1838  // Get the mangled function name.
1839  SmallString<128> Name;
1840  {
1841  llvm::raw_svector_ostream OS(Name);
1842  const NamedDecl *ParentSEHFn = ParentCGF.CurSEHParent;
1843  assert(ParentSEHFn && "No CurSEHParent!");
1844  MangleContext &Mangler = CGM.getCXXABI().getMangleContext();
1845  if (IsFilter)
1846  Mangler.mangleSEHFilterExpression(ParentSEHFn, OS);
1847  else
1848  Mangler.mangleSEHFinallyBlock(ParentSEHFn, OS);
1849  }
1850 
1851  FunctionArgList Args;
1852  if (CGM.getTarget().getTriple().getArch() != llvm::Triple::x86 || !IsFilter) {
1853  // All SEH finally functions take two parameters. Win64 filters take two
1854  // parameters. Win32 filters take no parameters.
1855  if (IsFilter) {
1856  Args.push_back(ImplicitParamDecl::Create(
1857  getContext(), /*DC=*/nullptr, StartLoc,
1858  &getContext().Idents.get("exception_pointers"),
1860  } else {
1861  Args.push_back(ImplicitParamDecl::Create(
1862  getContext(), /*DC=*/nullptr, StartLoc,
1863  &getContext().Idents.get("abnormal_termination"),
1865  }
1866  Args.push_back(ImplicitParamDecl::Create(
1867  getContext(), /*DC=*/nullptr, StartLoc,
1868  &getContext().Idents.get("frame_pointer"), getContext().VoidPtrTy,
1870  }
1871 
1872  QualType RetTy = IsFilter ? getContext().LongTy : getContext().VoidTy;
1873 
1874  const CGFunctionInfo &FnInfo =
1875  CGM.getTypes().arrangeBuiltinFunctionDeclaration(RetTy, Args);
1876 
1877  llvm::FunctionType *FnTy = CGM.getTypes().GetFunctionType(FnInfo);
1878  llvm::Function *Fn = llvm::Function::Create(
1879  FnTy, llvm::GlobalValue::InternalLinkage, Name.str(), &CGM.getModule());
1880 
1881  IsOutlinedSEHHelper = true;
1882 
1883  StartFunction(GlobalDecl(), RetTy, Fn, FnInfo, Args,
1884  OutlinedStmt->getBeginLoc(), OutlinedStmt->getBeginLoc());
1885  CurSEHParent = ParentCGF.CurSEHParent;
1886 
1887  CGM.SetLLVMFunctionAttributes(GlobalDecl(), FnInfo, CurFn);
1888  EmitCapturedLocals(ParentCGF, OutlinedStmt, IsFilter);
1889 }
1890 
1891 /// Create a stub filter function that will ultimately hold the code of the
1892 /// filter expression. The EH preparation passes in LLVM will outline the code
1893 /// from the main function body into this stub.
1894 llvm::Function *
1896  const SEHExceptStmt &Except) {
1897  const Expr *FilterExpr = Except.getFilterExpr();
1898  startOutlinedSEHHelper(ParentCGF, true, FilterExpr);
1899 
1900  // Emit the original filter expression, convert to i32, and return.
1901  llvm::Value *R = EmitScalarExpr(FilterExpr);
1902  R = Builder.CreateIntCast(R, ConvertType(getContext().LongTy),
1903  FilterExpr->getType()->isSignedIntegerType());
1904  Builder.CreateStore(R, ReturnValue);
1905 
1906  FinishFunction(FilterExpr->getEndLoc());
1907 
1908  return CurFn;
1909 }
1910 
1911 llvm::Function *
1913  const SEHFinallyStmt &Finally) {
1914  const Stmt *FinallyBlock = Finally.getBlock();
1915  startOutlinedSEHHelper(ParentCGF, false, FinallyBlock);
1916 
1917  // Emit the original filter expression, convert to i32, and return.
1918  EmitStmt(FinallyBlock);
1919 
1920  FinishFunction(FinallyBlock->getEndLoc());
1921 
1922  return CurFn;
1923 }
1924 
1926  llvm::Value *ParentFP,
1927  llvm::Value *EntryFP) {
1928  // Get the pointer to the EXCEPTION_POINTERS struct. This is returned by the
1929  // __exception_info intrinsic.
1930  if (CGM.getTarget().getTriple().getArch() != llvm::Triple::x86) {
1931  // On Win64, the info is passed as the first parameter to the filter.
1932  SEHInfo = &*CurFn->arg_begin();
1933  SEHCodeSlotStack.push_back(
1934  CreateMemTemp(getContext().IntTy, "__exception_code"));
1935  } else {
1936  // On Win32, the EBP on entry to the filter points to the end of an
1937  // exception registration object. It contains 6 32-bit fields, and the info
1938  // pointer is stored in the second field. So, GEP 20 bytes backwards and
1939  // load the pointer.
1940  SEHInfo = Builder.CreateConstInBoundsGEP1_32(Int8Ty, EntryFP, -20);
1941  SEHInfo = Builder.CreateBitCast(SEHInfo, Int8PtrTy->getPointerTo());
1942  SEHInfo = Builder.CreateAlignedLoad(Int8PtrTy, SEHInfo, getPointerAlign());
1943  SEHCodeSlotStack.push_back(recoverAddrOfEscapedLocal(
1944  ParentCGF, ParentCGF.SEHCodeSlotStack.back(), ParentFP));
1945  }
1946 
1947  // Save the exception code in the exception slot to unify exception access in
1948  // the filter function and the landing pad.
1949  // struct EXCEPTION_POINTERS {
1950  // EXCEPTION_RECORD *ExceptionRecord;
1951  // CONTEXT *ContextRecord;
1952  // };
1953  // int exceptioncode = exception_pointers->ExceptionRecord->ExceptionCode;
1954  llvm::Type *RecordTy = CGM.Int32Ty->getPointerTo();
1955  llvm::Type *PtrsTy = llvm::StructType::get(RecordTy, CGM.VoidPtrTy);
1956  llvm::Value *Ptrs = Builder.CreateBitCast(SEHInfo, PtrsTy->getPointerTo());
1957  llvm::Value *Rec = Builder.CreateStructGEP(PtrsTy, Ptrs, 0);
1958  Rec = Builder.CreateAlignedLoad(Rec, getPointerAlign());
1959  llvm::Value *Code = Builder.CreateAlignedLoad(Rec, getIntAlign());
1960  assert(!SEHCodeSlotStack.empty() && "emitting EH code outside of __except");
1961  Builder.CreateStore(Code, SEHCodeSlotStack.back());
1962 }
1963 
1965  // Sema should diagnose calling this builtin outside of a filter context, but
1966  // don't crash if we screw up.
1967  if (!SEHInfo)
1968  return llvm::UndefValue::get(Int8PtrTy);
1969  assert(SEHInfo->getType() == Int8PtrTy);
1970  return SEHInfo;
1971 }
1972 
1974  assert(!SEHCodeSlotStack.empty() && "emitting EH code outside of __except");
1975  return Builder.CreateLoad(SEHCodeSlotStack.back());
1976 }
1977 
1979  // Abnormal termination is just the first parameter to the outlined finally
1980  // helper.
1981  auto AI = CurFn->arg_begin();
1982  return Builder.CreateZExt(&*AI, Int32Ty);
1983 }
1984 
1986  llvm::Function *FinallyFunc) {
1987  EHStack.pushCleanup<PerformSEHFinally>(Kind, FinallyFunc);
1988 }
1989 
1991  CodeGenFunction HelperCGF(CGM, /*suppressNewContext=*/true);
1992  if (const SEHFinallyStmt *Finally = S.getFinallyHandler()) {
1993  // Outline the finally block.
1994  llvm::Function *FinallyFunc =
1995  HelperCGF.GenerateSEHFinallyFunction(*this, *Finally);
1996 
1997  // Push a cleanup for __finally blocks.
1998  EHStack.pushCleanup<PerformSEHFinally>(NormalAndEHCleanup, FinallyFunc);
1999  return;
2000  }
2001 
2002  // Otherwise, we must have an __except block.
2003  const SEHExceptStmt *Except = S.getExceptHandler();
2004  assert(Except);
2005  EHCatchScope *CatchScope = EHStack.pushCatch(1);
2006  SEHCodeSlotStack.push_back(
2007  CreateMemTemp(getContext().IntTy, "__exception_code"));
2008 
2009  // If the filter is known to evaluate to 1, then we can use the clause
2010  // "catch i8* null". We can't do this on x86 because the filter has to save
2011  // the exception code.
2012  llvm::Constant *C =
2014  getContext().IntTy);
2015  if (CGM.getTarget().getTriple().getArch() != llvm::Triple::x86 && C &&
2016  C->isOneValue()) {
2017  CatchScope->setCatchAllHandler(0, createBasicBlock("__except"));
2018  return;
2019  }
2020 
2021  // In general, we have to emit an outlined filter function. Use the function
2022  // in place of the RTTI typeinfo global that C++ EH uses.
2023  llvm::Function *FilterFunc =
2024  HelperCGF.GenerateSEHFilterFunction(*this, *Except);
2025  llvm::Constant *OpaqueFunc =
2026  llvm::ConstantExpr::getBitCast(FilterFunc, Int8PtrTy);
2027  CatchScope->setHandler(0, OpaqueFunc, createBasicBlock("__except.ret"));
2028 }
2029 
2031  // Just pop the cleanup if it's a __finally block.
2032  if (S.getFinallyHandler()) {
2033  PopCleanupBlock();
2034  return;
2035  }
2036 
2037  // Otherwise, we must have an __except block.
2038  const SEHExceptStmt *Except = S.getExceptHandler();
2039  assert(Except && "__try must have __finally xor __except");
2040  EHCatchScope &CatchScope = cast<EHCatchScope>(*EHStack.begin());
2041 
2042  // Don't emit the __except block if the __try block lacked invokes.
2043  // TODO: Model unwind edges from instructions, either with iload / istore or
2044  // a try body function.
2045  if (!CatchScope.hasEHBranches()) {
2046  CatchScope.clearHandlerBlocks();
2047  EHStack.popCatch();
2048  SEHCodeSlotStack.pop_back();
2049  return;
2050  }
2051 
2052  // The fall-through block.
2053  llvm::BasicBlock *ContBB = createBasicBlock("__try.cont");
2054 
2055  // We just emitted the body of the __try; jump to the continue block.
2056  if (HaveInsertPoint())
2057  Builder.CreateBr(ContBB);
2058 
2059  // Check if our filter function returned true.
2060  emitCatchDispatchBlock(*this, CatchScope);
2061 
2062  // Grab the block before we pop the handler.
2063  llvm::BasicBlock *CatchPadBB = CatchScope.getHandler(0).Block;
2064  EHStack.popCatch();
2065 
2066  EmitBlockAfterUses(CatchPadBB);
2067 
2068  // __except blocks don't get outlined into funclets, so immediately do a
2069  // catchret.
2070  llvm::CatchPadInst *CPI =
2071  cast<llvm::CatchPadInst>(CatchPadBB->getFirstNonPHI());
2072  llvm::BasicBlock *ExceptBB = createBasicBlock("__except");
2073  Builder.CreateCatchRet(CPI, ExceptBB);
2074  EmitBlock(ExceptBB);
2075 
2076  // On Win64, the exception code is returned in EAX. Copy it into the slot.
2077  if (CGM.getTarget().getTriple().getArch() != llvm::Triple::x86) {
2078  llvm::Function *SEHCodeIntrin =
2079  CGM.getIntrinsic(llvm::Intrinsic::eh_exceptioncode);
2080  llvm::Value *Code = Builder.CreateCall(SEHCodeIntrin, {CPI});
2081  Builder.CreateStore(Code, SEHCodeSlotStack.back());
2082  }
2083 
2084  // Emit the __except body.
2085  EmitStmt(Except->getBlock());
2086 
2087  // End the lifetime of the exception code.
2088  SEHCodeSlotStack.pop_back();
2089 
2090  if (HaveInsertPoint())
2091  Builder.CreateBr(ContBB);
2092 
2093  EmitBlock(ContBB);
2094 }
2095 
2097  // If this code is reachable then emit a stop point (if generating
2098  // debug info). We have to do this ourselves because we are on the
2099  // "simple" statement path.
2100  if (HaveInsertPoint())
2101  EmitStopPoint(&S);
2102 
2103  // This must be a __leave from a __finally block, which we warn on and is UB.
2104  // Just emit unreachable.
2105  if (!isSEHTryScope()) {
2106  Builder.CreateUnreachable();
2107  Builder.ClearInsertionPoint();
2108  return;
2109  }
2110 
2111  EmitBranchThroughCleanup(*SEHTryEpilogueStack.back());
2112 }
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:363
static llvm::FunctionCallee getFreeExceptionFn(CodeGenModule &CGM)
Definition: CGException.cpp:31
Represents a function declaration or definition.
Definition: Decl.h:1784
llvm::IntegerType * IntTy
int
EHScopeStack::stable_iterator getEnclosingEHScope() const
Definition: CGCleanup.h:137
Other implicit parameter.
Definition: Decl.h:1560
CompoundStmt * getBlock() const
Definition: Stmt.h:3253
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:1043
A (possibly-)qualified type.
Definition: Type.h:643
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:3987
const Expr * getSubExpr() const
Definition: ExprCXX.h:1162
ConstStmtVisitor - This class implements a simple visitor for Stmt subclasses.
Definition: StmtVisitor.h:192
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:991
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:2454
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:6339
Represents Objective-C&#39;s @throw statement.
Definition: StmtObjC.h:332
CanQualType LongTy
Definition: ASTContext.h:1024
void EmitSEHExceptionCodeSave(CodeGenFunction &ParentCGF, llvm::Value *ParentFP, llvm::Value *EntryEBP)
bool usesSEHTry() const
Indicates the function uses __try.
Definition: Decl.h:2177
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:827
const T * getAs() const
Member-template getAs<specific type>&#39;.
Definition: Type.h:6858
llvm::FunctionCallee getTerminateFn()
Get the declaration of std::terminate for the platform.
Definition: CGException.cpp:49
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:137
void add(RValue rvalue, QualType type)
Definition: CGCall.h:287
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:160
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:274
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:49
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:3995
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:223
const Handler & getHandler(unsigned I) const
Definition: CGCleanup.h:208
static llvm::FunctionCallee getUnexpectedFn(CodeGenModule &CGM)
Definition: CGException.cpp:40
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:4140
llvm::AllocaInst * CreateTempAlloca(llvm::Type *Ty, const Twine &Name="tmp", llvm::Value *ArraySize=nullptr)
CreateTempAlloca - This creates an alloca and inserts it into the entry block if ArraySize is nullptr...
Definition: CGExpr.cpp:106
CanQualType UnsignedCharTy
Definition: ASTContext.h:1025
Represents the this expression in C++.
Definition: ExprCXX.h:1097
static ImplicitParamDecl * Create(ASTContext &C, DeclContext *DC, SourceLocation IdLoc, IdentifierInfo *Id, QualType T, ImplicitParamKind ParamKind)
Create implicit parameter.
Definition: Decl.cpp:4603
&#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:3725
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:163
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:1352
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:639
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:1931
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:223
llvm::PointerType * AllocaInt8PtrTy
static const EHPersonality GNU_ObjC_SEH
Definition: CGCleanup.h:619
const TargetInfo & getTarget() const
ValueDecl * getDecl()
Definition: Expr.h:1222
&#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:75
GlobalDecl - represents a global declaration.
Definition: GlobalDecl.h:40
SourceLocation getEndLoc() const LLVM_READONLY
Definition: Stmt.cpp:287
unsigned getBuiltinCallee() const
getBuiltinCallee - If this is a call to a builtin, return the builtin ID of the callee.
Definition: Expr.cpp:1468
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:2137
&#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:3779
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:44
CanQualType VoidTy
Definition: ASTContext.h:1015
bool isObjCObjectPointerType() const
Definition: Type.h:6495
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:3961
SourceLocation getExprLoc() const LLVM_READONLY
getExprLoc - Return the preferred location for the arrow when diagnosing a problem with a generic exp...
Definition: Expr.cpp:221
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:358
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:749
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:1135
llvm::Function * getIntrinsic(unsigned IID, ArrayRef< llvm::Type *> Tys=None)
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:3321
&#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:3095
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.
llvm::FunctionCallee CreateRuntimeFunction(llvm::FunctionType *Ty, StringRef Name, llvm::AttributeList ExtraAttrs=llvm::AttributeList(), bool Local=false)
Create or return a runtime function declaration with the specified type and name. ...
void EmitBlock(llvm::BasicBlock *BB, bool IsFinished=false)
EmitBlock - Emit the given block.
Definition: CGStmt.cpp:465
void EnterCXXTryStmt(const CXXTryStmt &S, bool IsFnTryBlock=false)
SEHFinallyStmt * getFinallyHandler() const
Definition: Stmt.cpp:1139
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:6228
Expr * getFilterExpr() const
Definition: Stmt.h:3212
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:6175
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:2521
llvm::Constant * tryEmitAbstract(const Expr *E, QualType T)
Try to emit the result of the given expression as an abstract constant.
void EnterSEHTryStmt(const SEHTryStmt &S)
void startOutlinedSEHHelper(CodeGenFunction &ParentCGF, bool IsFilter, const Stmt *OutlinedStmt)
Arrange a function prototype that can be called by Windows exception handling personalities.
CGCXXABI & getCXXABI() const
CanQualType IntTy
Definition: ASTContext.h:1024
An exceptions scope which filters exceptions thrown through it.
Definition: CGCleanup.h:437
A reference to a declared variable, function, enum, etc.
Definition: Expr.h:1146
static RValue get(llvm::Value *V)
Definition: CGValue.h:85
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:655
Information for lazily generating a cleanup.
Definition: EHScopeStack.h:146
This represents a decl that may have a name.
Definition: Decl.h:248
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:502
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:3739
CallArgList - Type for representing both the value and type of arguments in a call.
Definition: CGCall.h:262
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:3297
CompoundStmt * getBlock() const
Definition: Stmt.h:3216
void EmitCXXThrowExpr(const CXXThrowExpr *E, bool KeepInsertionPoint=true)
bool isLocalVarDeclOrParm() const
Similar to isLocalVarDecl but also includes parameters.
Definition: Decl.h:1128
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)