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CGException.cpp
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1 //===--- CGException.cpp - Emit LLVM Code for C++ exceptions ----*- C++ -*-===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This contains code dealing with C++ exception related code generation.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "CodeGenFunction.h"
15 #include "CGCXXABI.h"
16 #include "CGCleanup.h"
17 #include "CGObjCRuntime.h"
18 #include "ConstantEmitter.h"
19 #include "TargetInfo.h"
20 #include "clang/AST/Mangle.h"
21 #include "clang/AST/StmtCXX.h"
22 #include "clang/AST/StmtObjC.h"
23 #include "clang/AST/StmtVisitor.h"
25 #include "llvm/IR/CallSite.h"
26 #include "llvm/IR/Intrinsics.h"
27 #include "llvm/IR/IntrinsicInst.h"
28 #include "llvm/Support/SaveAndRestore.h"
29 
30 using namespace clang;
31 using namespace CodeGen;
32 
33 static llvm::Constant *getFreeExceptionFn(CodeGenModule &CGM) {
34  // void __cxa_free_exception(void *thrown_exception);
35 
36  llvm::FunctionType *FTy =
37  llvm::FunctionType::get(CGM.VoidTy, CGM.Int8PtrTy, /*IsVarArgs=*/false);
38 
39  return CGM.CreateRuntimeFunction(FTy, "__cxa_free_exception");
40 }
41 
42 static llvm::Constant *getUnexpectedFn(CodeGenModule &CGM) {
43  // void __cxa_call_unexpected(void *thrown_exception);
44 
45  llvm::FunctionType *FTy =
46  llvm::FunctionType::get(CGM.VoidTy, CGM.Int8PtrTy, /*IsVarArgs=*/false);
47 
48  return CGM.CreateRuntimeFunction(FTy, "__cxa_call_unexpected");
49 }
50 
51 llvm::Constant *CodeGenModule::getTerminateFn() {
52  // void __terminate();
53 
54  llvm::FunctionType *FTy =
55  llvm::FunctionType::get(VoidTy, /*IsVarArgs=*/false);
56 
57  StringRef name;
58 
59  // In C++, use std::terminate().
60  if (getLangOpts().CPlusPlus &&
61  getTarget().getCXXABI().isItaniumFamily()) {
62  name = "_ZSt9terminatev";
63  } else if (getLangOpts().CPlusPlus &&
64  getTarget().getCXXABI().isMicrosoft()) {
65  if (getLangOpts().isCompatibleWithMSVC(LangOptions::MSVC2015))
66  name = "__std_terminate";
67  else
68  name = "\01?terminate@@YAXXZ";
69  } else if (getLangOpts().ObjC1 &&
71  name = "objc_terminate";
72  else
73  name = "abort";
74  return CreateRuntimeFunction(FTy, name);
75 }
76 
77 static llvm::Constant *getCatchallRethrowFn(CodeGenModule &CGM,
78  StringRef Name) {
79  llvm::FunctionType *FTy =
80  llvm::FunctionType::get(CGM.VoidTy, CGM.Int8PtrTy, /*IsVarArgs=*/false);
81 
82  return CGM.CreateRuntimeFunction(FTy, Name);
83 }
84 
85 const EHPersonality EHPersonality::GNU_C = { "__gcc_personality_v0", nullptr };
86 const EHPersonality
87 EHPersonality::GNU_C_SJLJ = { "__gcc_personality_sj0", nullptr };
88 const EHPersonality
89 EHPersonality::GNU_C_SEH = { "__gcc_personality_seh0", nullptr };
90 const EHPersonality
91 EHPersonality::NeXT_ObjC = { "__objc_personality_v0", nullptr };
92 const EHPersonality
93 EHPersonality::GNU_CPlusPlus = { "__gxx_personality_v0", nullptr };
94 const EHPersonality
95 EHPersonality::GNU_CPlusPlus_SJLJ = { "__gxx_personality_sj0", nullptr };
96 const EHPersonality
97 EHPersonality::GNU_CPlusPlus_SEH = { "__gxx_personality_seh0", nullptr };
98 const EHPersonality
99 EHPersonality::GNU_ObjC = {"__gnu_objc_personality_v0", "objc_exception_throw"};
100 const EHPersonality
101 EHPersonality::GNU_ObjC_SJLJ = {"__gnu_objc_personality_sj0", "objc_exception_throw"};
102 const EHPersonality
103 EHPersonality::GNU_ObjC_SEH = {"__gnu_objc_personality_seh0", "objc_exception_throw"};
104 const EHPersonality
105 EHPersonality::GNU_ObjCXX = { "__gnustep_objcxx_personality_v0", nullptr };
106 const EHPersonality
107 EHPersonality::GNUstep_ObjC = { "__gnustep_objc_personality_v0", nullptr };
108 const EHPersonality
109 EHPersonality::MSVC_except_handler = { "_except_handler3", nullptr };
110 const EHPersonality
111 EHPersonality::MSVC_C_specific_handler = { "__C_specific_handler", nullptr };
112 const EHPersonality
113 EHPersonality::MSVC_CxxFrameHandler3 = { "__CxxFrameHandler3", nullptr };
114 
115 /// On Win64, use libgcc's SEH personality function. We fall back to dwarf on
116 /// other platforms, unless the user asked for SjLj exceptions.
117 static bool useLibGCCSEHPersonality(const llvm::Triple &T) {
118  return T.isOSWindows() && T.getArch() == llvm::Triple::x86_64;
119 }
120 
121 static const EHPersonality &getCPersonality(const llvm::Triple &T,
122  const LangOptions &L) {
123  if (L.SjLjExceptions)
125  else if (useLibGCCSEHPersonality(T))
127  return EHPersonality::GNU_C;
128 }
129 
130 static const EHPersonality &getObjCPersonality(const llvm::Triple &T,
131  const LangOptions &L) {
132  switch (L.ObjCRuntime.getKind()) {
134  return getCPersonality(T, L);
135  case ObjCRuntime::MacOSX:
136  case ObjCRuntime::iOS:
140  if (L.ObjCRuntime.getVersion() >= VersionTuple(1, 7))
141  return EHPersonality::GNUstep_ObjC;
142  // fallthrough
143  case ObjCRuntime::GCC:
144  case ObjCRuntime::ObjFW:
145  if (L.SjLjExceptions)
147  else if (useLibGCCSEHPersonality(T))
148  return EHPersonality::GNU_ObjC_SEH;
150  }
151  llvm_unreachable("bad runtime kind");
152 }
153 
154 static const EHPersonality &getCXXPersonality(const llvm::Triple &T,
155  const LangOptions &L) {
156  if (L.SjLjExceptions)
158  else if (useLibGCCSEHPersonality(T))
161 }
162 
163 /// Determines the personality function to use when both C++
164 /// and Objective-C exceptions are being caught.
165 static const EHPersonality &getObjCXXPersonality(const llvm::Triple &T,
166  const LangOptions &L) {
167  switch (L.ObjCRuntime.getKind()) {
168  // The ObjC personality defers to the C++ personality for non-ObjC
169  // handlers. Unlike the C++ case, we use the same personality
170  // function on targets using (backend-driven) SJLJ EH.
171  case ObjCRuntime::MacOSX:
172  case ObjCRuntime::iOS:
175 
176  // In the fragile ABI, just use C++ exception handling and hope
177  // they're not doing crazy exception mixing.
179  return getCXXPersonality(T, L);
180 
181  // The GCC runtime's personality function inherently doesn't support
182  // mixed EH. Use the C++ personality just to avoid returning null.
183  case ObjCRuntime::GCC:
184  case ObjCRuntime::ObjFW:
185  return getObjCPersonality(T, L);
188  }
189  llvm_unreachable("bad runtime kind");
190 }
191 
192 static const EHPersonality &getSEHPersonalityMSVC(const llvm::Triple &T) {
193  if (T.getArch() == llvm::Triple::x86)
194  return EHPersonality::MSVC_except_handler;
196 }
197 
199  const FunctionDecl *FD) {
200  const llvm::Triple &T = CGM.getTarget().getTriple();
201  const LangOptions &L = CGM.getLangOpts();
202 
203  // Functions using SEH get an SEH personality.
204  if (FD && FD->usesSEHTry())
205  return getSEHPersonalityMSVC(T);
206 
207  // Try to pick a personality function that is compatible with MSVC if we're
208  // not compiling Obj-C. Obj-C users better have an Obj-C runtime that supports
209  // the GCC-style personality function.
210  if (T.isWindowsMSVCEnvironment() && !L.ObjC1) {
211  if (L.SjLjExceptions)
213  else
215  }
216 
217  if (L.CPlusPlus && L.ObjC1)
218  return getObjCXXPersonality(T, L);
219  else if (L.CPlusPlus)
220  return getCXXPersonality(T, L);
221  else if (L.ObjC1)
222  return getObjCPersonality(T, L);
223  else
224  return getCPersonality(T, L);
225 }
226 
228  const auto *FD = CGF.CurCodeDecl;
229  // For outlined finallys and filters, use the SEH personality in case they
230  // contain more SEH. This mostly only affects finallys. Filters could
231  // hypothetically use gnu statement expressions to sneak in nested SEH.
232  FD = FD ? FD : CGF.CurSEHParent;
233  return get(CGF.CGM, dyn_cast_or_null<FunctionDecl>(FD));
234 }
235 
236 static llvm::Constant *getPersonalityFn(CodeGenModule &CGM,
237  const EHPersonality &Personality) {
238  return CGM.CreateRuntimeFunction(llvm::FunctionType::get(CGM.Int32Ty, true),
239  Personality.PersonalityFn,
240  llvm::AttributeList(), /*Local=*/true);
241 }
242 
243 static llvm::Constant *getOpaquePersonalityFn(CodeGenModule &CGM,
244  const EHPersonality &Personality) {
245  llvm::Constant *Fn = getPersonalityFn(CGM, Personality);
246  return llvm::ConstantExpr::getBitCast(Fn, CGM.Int8PtrTy);
247 }
248 
249 /// Check whether a landingpad instruction only uses C++ features.
250 static bool LandingPadHasOnlyCXXUses(llvm::LandingPadInst *LPI) {
251  for (unsigned I = 0, E = LPI->getNumClauses(); I != E; ++I) {
252  // Look for something that would've been returned by the ObjC
253  // runtime's GetEHType() method.
254  llvm::Value *Val = LPI->getClause(I)->stripPointerCasts();
255  if (LPI->isCatch(I)) {
256  // Check if the catch value has the ObjC prefix.
257  if (llvm::GlobalVariable *GV = dyn_cast<llvm::GlobalVariable>(Val))
258  // ObjC EH selector entries are always global variables with
259  // names starting like this.
260  if (GV->getName().startswith("OBJC_EHTYPE"))
261  return false;
262  } else {
263  // Check if any of the filter values have the ObjC prefix.
264  llvm::Constant *CVal = cast<llvm::Constant>(Val);
265  for (llvm::User::op_iterator
266  II = CVal->op_begin(), IE = CVal->op_end(); II != IE; ++II) {
267  if (llvm::GlobalVariable *GV =
268  cast<llvm::GlobalVariable>((*II)->stripPointerCasts()))
269  // ObjC EH selector entries are always global variables with
270  // names starting like this.
271  if (GV->getName().startswith("OBJC_EHTYPE"))
272  return false;
273  }
274  }
275  }
276  return true;
277 }
278 
279 /// Check whether a personality function could reasonably be swapped
280 /// for a C++ personality function.
281 static bool PersonalityHasOnlyCXXUses(llvm::Constant *Fn) {
282  for (llvm::User *U : Fn->users()) {
283  // Conditionally white-list bitcasts.
284  if (llvm::ConstantExpr *CE = dyn_cast<llvm::ConstantExpr>(U)) {
285  if (CE->getOpcode() != llvm::Instruction::BitCast) return false;
286  if (!PersonalityHasOnlyCXXUses(CE))
287  return false;
288  continue;
289  }
290 
291  // Otherwise it must be a function.
292  llvm::Function *F = dyn_cast<llvm::Function>(U);
293  if (!F) return false;
294 
295  for (auto BB = F->begin(), E = F->end(); BB != E; ++BB) {
296  if (BB->isLandingPad())
297  if (!LandingPadHasOnlyCXXUses(BB->getLandingPadInst()))
298  return false;
299  }
300  }
301 
302  return true;
303 }
304 
305 /// Try to use the C++ personality function in ObjC++. Not doing this
306 /// can cause some incompatibilities with gcc, which is more
307 /// aggressive about only using the ObjC++ personality in a function
308 /// when it really needs it.
309 void CodeGenModule::SimplifyPersonality() {
310  // If we're not in ObjC++ -fexceptions, there's nothing to do.
311  if (!LangOpts.CPlusPlus || !LangOpts.ObjC1 || !LangOpts.Exceptions)
312  return;
313 
314  // Both the problem this endeavors to fix and the way the logic
315  // above works is specific to the NeXT runtime.
316  if (!LangOpts.ObjCRuntime.isNeXTFamily())
317  return;
318 
319  const EHPersonality &ObjCXX = EHPersonality::get(*this, /*FD=*/nullptr);
320  const EHPersonality &CXX =
321  getCXXPersonality(getTarget().getTriple(), LangOpts);
322  if (&ObjCXX == &CXX)
323  return;
324 
325  assert(std::strcmp(ObjCXX.PersonalityFn, CXX.PersonalityFn) != 0 &&
326  "Different EHPersonalities using the same personality function.");
327 
328  llvm::Function *Fn = getModule().getFunction(ObjCXX.PersonalityFn);
329 
330  // Nothing to do if it's unused.
331  if (!Fn || Fn->use_empty()) return;
332 
333  // Can't do the optimization if it has non-C++ uses.
334  if (!PersonalityHasOnlyCXXUses(Fn)) return;
335 
336  // Create the C++ personality function and kill off the old
337  // function.
338  llvm::Constant *CXXFn = getPersonalityFn(*this, CXX);
339 
340  // This can happen if the user is screwing with us.
341  if (Fn->getType() != CXXFn->getType()) return;
342 
343  Fn->replaceAllUsesWith(CXXFn);
344  Fn->eraseFromParent();
345 }
346 
347 /// Returns the value to inject into a selector to indicate the
348 /// presence of a catch-all.
349 static llvm::Constant *getCatchAllValue(CodeGenFunction &CGF) {
350  // Possibly we should use @llvm.eh.catch.all.value here.
351  return llvm::ConstantPointerNull::get(CGF.Int8PtrTy);
352 }
353 
354 namespace {
355  /// A cleanup to free the exception object if its initialization
356  /// throws.
357  struct FreeException final : EHScopeStack::Cleanup {
358  llvm::Value *exn;
359  FreeException(llvm::Value *exn) : exn(exn) {}
360  void Emit(CodeGenFunction &CGF, Flags flags) override {
362  }
363  };
364 } // end anonymous namespace
365 
366 // Emits an exception expression into the given location. This
367 // differs from EmitAnyExprToMem only in that, if a final copy-ctor
368 // call is required, an exception within that copy ctor causes
369 // std::terminate to be invoked.
371  // Make sure the exception object is cleaned up if there's an
372  // exception during initialization.
373  pushFullExprCleanup<FreeException>(EHCleanup, addr.getPointer());
374  EHScopeStack::stable_iterator cleanup = EHStack.stable_begin();
375 
376  // __cxa_allocate_exception returns a void*; we need to cast this
377  // to the appropriate type for the object.
378  llvm::Type *ty = ConvertTypeForMem(e->getType())->getPointerTo();
379  Address typedAddr = Builder.CreateBitCast(addr, ty);
380 
381  // FIXME: this isn't quite right! If there's a final unelided call
382  // to a copy constructor, then according to [except.terminate]p1 we
383  // must call std::terminate() if that constructor throws, because
384  // technically that copy occurs after the exception expression is
385  // evaluated but before the exception is caught. But the best way
386  // to handle that is to teach EmitAggExpr to do the final copy
387  // differently if it can't be elided.
388  EmitAnyExprToMem(e, typedAddr, e->getType().getQualifiers(),
389  /*IsInit*/ true);
390 
391  // Deactivate the cleanup block.
392  DeactivateCleanupBlock(cleanup,
393  cast<llvm::Instruction>(typedAddr.getPointer()));
394 }
395 
397  if (!ExceptionSlot)
398  ExceptionSlot = CreateTempAlloca(Int8PtrTy, "exn.slot");
399  return Address(ExceptionSlot, getPointerAlign());
400 }
401 
403  if (!EHSelectorSlot)
404  EHSelectorSlot = CreateTempAlloca(Int32Ty, "ehselector.slot");
405  return Address(EHSelectorSlot, CharUnits::fromQuantity(4));
406 }
407 
409  return Builder.CreateLoad(getExceptionSlot(), "exn");
410 }
411 
413  return Builder.CreateLoad(getEHSelectorSlot(), "sel");
414 }
415 
417  bool KeepInsertionPoint) {
418  if (const Expr *SubExpr = E->getSubExpr()) {
419  QualType ThrowType = SubExpr->getType();
420  if (ThrowType->isObjCObjectPointerType()) {
421  const Stmt *ThrowStmt = E->getSubExpr();
422  const ObjCAtThrowStmt S(E->getExprLoc(), const_cast<Stmt *>(ThrowStmt));
423  CGM.getObjCRuntime().EmitThrowStmt(*this, S, false);
424  } else {
425  CGM.getCXXABI().emitThrow(*this, E);
426  }
427  } else {
428  CGM.getCXXABI().emitRethrow(*this, /*isNoReturn=*/true);
429  }
430 
431  // throw is an expression, and the expression emitters expect us
432  // to leave ourselves at a valid insertion point.
433  if (KeepInsertionPoint)
434  EmitBlock(createBasicBlock("throw.cont"));
435 }
436 
438  if (!CGM.getLangOpts().CXXExceptions)
439  return;
440 
441  const FunctionDecl* FD = dyn_cast_or_null<FunctionDecl>(D);
442  if (!FD) {
443  // Check if CapturedDecl is nothrow and create terminate scope for it.
444  if (const CapturedDecl* CD = dyn_cast_or_null<CapturedDecl>(D)) {
445  if (CD->isNothrow())
446  EHStack.pushTerminate();
447  }
448  return;
449  }
450  const FunctionProtoType *Proto = FD->getType()->getAs<FunctionProtoType>();
451  if (!Proto)
452  return;
453 
455  if (isNoexceptExceptionSpec(EST)) {
457  // noexcept functions are simple terminate scopes.
458  EHStack.pushTerminate();
459  }
460  } else if (EST == EST_Dynamic || EST == EST_DynamicNone) {
461  // TODO: Revisit exception specifications for the MS ABI. There is a way to
462  // encode these in an object file but MSVC doesn't do anything with it.
463  if (getTarget().getCXXABI().isMicrosoft())
464  return;
465  unsigned NumExceptions = Proto->getNumExceptions();
466  EHFilterScope *Filter = EHStack.pushFilter(NumExceptions);
467 
468  for (unsigned I = 0; I != NumExceptions; ++I) {
469  QualType Ty = Proto->getExceptionType(I);
470  QualType ExceptType = Ty.getNonReferenceType().getUnqualifiedType();
471  llvm::Value *EHType = CGM.GetAddrOfRTTIDescriptor(ExceptType,
472  /*ForEH=*/true);
473  Filter->setFilter(I, EHType);
474  }
475  }
476 }
477 
478 /// Emit the dispatch block for a filter scope if necessary.
480  EHFilterScope &filterScope) {
481  llvm::BasicBlock *dispatchBlock = filterScope.getCachedEHDispatchBlock();
482  if (!dispatchBlock) return;
483  if (dispatchBlock->use_empty()) {
484  delete dispatchBlock;
485  return;
486  }
487 
488  CGF.EmitBlockAfterUses(dispatchBlock);
489 
490  // If this isn't a catch-all filter, we need to check whether we got
491  // here because the filter triggered.
492  if (filterScope.getNumFilters()) {
493  // Load the selector value.
494  llvm::Value *selector = CGF.getSelectorFromSlot();
495  llvm::BasicBlock *unexpectedBB = CGF.createBasicBlock("ehspec.unexpected");
496 
497  llvm::Value *zero = CGF.Builder.getInt32(0);
498  llvm::Value *failsFilter =
499  CGF.Builder.CreateICmpSLT(selector, zero, "ehspec.fails");
500  CGF.Builder.CreateCondBr(failsFilter, unexpectedBB,
501  CGF.getEHResumeBlock(false));
502 
503  CGF.EmitBlock(unexpectedBB);
504  }
505 
506  // Call __cxa_call_unexpected. This doesn't need to be an invoke
507  // because __cxa_call_unexpected magically filters exceptions
508  // according to the last landing pad the exception was thrown
509  // into. Seriously.
510  llvm::Value *exn = CGF.getExceptionFromSlot();
511  CGF.EmitRuntimeCall(getUnexpectedFn(CGF.CGM), exn)
512  ->setDoesNotReturn();
513  CGF.Builder.CreateUnreachable();
514 }
515 
517  if (!CGM.getLangOpts().CXXExceptions)
518  return;
519 
520  const FunctionDecl* FD = dyn_cast_or_null<FunctionDecl>(D);
521  if (!FD) {
522  // Check if CapturedDecl is nothrow and pop terminate scope for it.
523  if (const CapturedDecl* CD = dyn_cast_or_null<CapturedDecl>(D)) {
524  if (CD->isNothrow())
525  EHStack.popTerminate();
526  }
527  return;
528  }
529  const FunctionProtoType *Proto = FD->getType()->getAs<FunctionProtoType>();
530  if (!Proto)
531  return;
532 
534  if (isNoexceptExceptionSpec(EST)) {
536  EHStack.popTerminate();
537  }
538  } else if (EST == EST_Dynamic || EST == EST_DynamicNone) {
539  // TODO: Revisit exception specifications for the MS ABI. There is a way to
540  // encode these in an object file but MSVC doesn't do anything with it.
541  if (getTarget().getCXXABI().isMicrosoft())
542  return;
543  EHFilterScope &filterScope = cast<EHFilterScope>(*EHStack.begin());
544  emitFilterDispatchBlock(*this, filterScope);
545  EHStack.popFilter();
546  }
547 }
548 
550  EnterCXXTryStmt(S);
551  EmitStmt(S.getTryBlock());
552  ExitCXXTryStmt(S);
553 }
554 
555 void CodeGenFunction::EnterCXXTryStmt(const CXXTryStmt &S, bool IsFnTryBlock) {
556  unsigned NumHandlers = S.getNumHandlers();
557  EHCatchScope *CatchScope = EHStack.pushCatch(NumHandlers);
558 
559  for (unsigned I = 0; I != NumHandlers; ++I) {
560  const CXXCatchStmt *C = S.getHandler(I);
561 
562  llvm::BasicBlock *Handler = createBasicBlock("catch");
563  if (C->getExceptionDecl()) {
564  // FIXME: Dropping the reference type on the type into makes it
565  // impossible to correctly implement catch-by-reference
566  // semantics for pointers. Unfortunately, this is what all
567  // existing compilers do, and it's not clear that the standard
568  // personality routine is capable of doing this right. See C++ DR 388:
569  // http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_active.html#388
570  Qualifiers CaughtTypeQuals;
571  QualType CaughtType = CGM.getContext().getUnqualifiedArrayType(
572  C->getCaughtType().getNonReferenceType(), CaughtTypeQuals);
573 
574  CatchTypeInfo TypeInfo{nullptr, 0};
575  if (CaughtType->isObjCObjectPointerType())
576  TypeInfo.RTTI = CGM.getObjCRuntime().GetEHType(CaughtType);
577  else
578  TypeInfo = CGM.getCXXABI().getAddrOfCXXCatchHandlerType(
579  CaughtType, C->getCaughtType());
580  CatchScope->setHandler(I, TypeInfo, Handler);
581  } else {
582  // No exception decl indicates '...', a catch-all.
583  CatchScope->setHandler(I, CGM.getCXXABI().getCatchAllTypeInfo(), Handler);
584  }
585  }
586 }
587 
588 llvm::BasicBlock *
590  if (EHPersonality::get(*this).usesFuncletPads())
591  return getMSVCDispatchBlock(si);
592 
593  // The dispatch block for the end of the scope chain is a block that
594  // just resumes unwinding.
595  if (si == EHStack.stable_end())
596  return getEHResumeBlock(true);
597 
598  // Otherwise, we should look at the actual scope.
599  EHScope &scope = *EHStack.find(si);
600 
601  llvm::BasicBlock *dispatchBlock = scope.getCachedEHDispatchBlock();
602  if (!dispatchBlock) {
603  switch (scope.getKind()) {
604  case EHScope::Catch: {
605  // Apply a special case to a single catch-all.
606  EHCatchScope &catchScope = cast<EHCatchScope>(scope);
607  if (catchScope.getNumHandlers() == 1 &&
608  catchScope.getHandler(0).isCatchAll()) {
609  dispatchBlock = catchScope.getHandler(0).Block;
610 
611  // Otherwise, make a dispatch block.
612  } else {
613  dispatchBlock = createBasicBlock("catch.dispatch");
614  }
615  break;
616  }
617 
618  case EHScope::Cleanup:
619  dispatchBlock = createBasicBlock("ehcleanup");
620  break;
621 
622  case EHScope::Filter:
623  dispatchBlock = createBasicBlock("filter.dispatch");
624  break;
625 
626  case EHScope::Terminate:
627  dispatchBlock = getTerminateHandler();
628  break;
629 
630  case EHScope::PadEnd:
631  llvm_unreachable("PadEnd unnecessary for Itanium!");
632  }
633  scope.setCachedEHDispatchBlock(dispatchBlock);
634  }
635  return dispatchBlock;
636 }
637 
638 llvm::BasicBlock *
640  // Returning nullptr indicates that the previous dispatch block should unwind
641  // to caller.
642  if (SI == EHStack.stable_end())
643  return nullptr;
644 
645  // Otherwise, we should look at the actual scope.
646  EHScope &EHS = *EHStack.find(SI);
647 
648  llvm::BasicBlock *DispatchBlock = EHS.getCachedEHDispatchBlock();
649  if (DispatchBlock)
650  return DispatchBlock;
651 
652  if (EHS.getKind() == EHScope::Terminate)
653  DispatchBlock = getTerminateHandler();
654  else
655  DispatchBlock = createBasicBlock();
656  CGBuilderTy Builder(*this, DispatchBlock);
657 
658  switch (EHS.getKind()) {
659  case EHScope::Catch:
660  DispatchBlock->setName("catch.dispatch");
661  break;
662 
663  case EHScope::Cleanup:
664  DispatchBlock->setName("ehcleanup");
665  break;
666 
667  case EHScope::Filter:
668  llvm_unreachable("exception specifications not handled yet!");
669 
670  case EHScope::Terminate:
671  DispatchBlock->setName("terminate");
672  break;
673 
674  case EHScope::PadEnd:
675  llvm_unreachable("PadEnd dispatch block missing!");
676  }
677  EHS.setCachedEHDispatchBlock(DispatchBlock);
678  return DispatchBlock;
679 }
680 
681 /// Check whether this is a non-EH scope, i.e. a scope which doesn't
682 /// affect exception handling. Currently, the only non-EH scopes are
683 /// normal-only cleanup scopes.
684 static bool isNonEHScope(const EHScope &S) {
685  switch (S.getKind()) {
686  case EHScope::Cleanup:
687  return !cast<EHCleanupScope>(S).isEHCleanup();
688  case EHScope::Filter:
689  case EHScope::Catch:
690  case EHScope::Terminate:
691  case EHScope::PadEnd:
692  return false;
693  }
694 
695  llvm_unreachable("Invalid EHScope Kind!");
696 }
697 
699  assert(EHStack.requiresLandingPad());
700  assert(!EHStack.empty());
701 
702  // If exceptions are disabled and SEH is not in use, then there is no invoke
703  // destination. SEH "works" even if exceptions are off. In practice, this
704  // means that C++ destructors and other EH cleanups don't run, which is
705  // consistent with MSVC's behavior.
706  const LangOptions &LO = CGM.getLangOpts();
707  if (!LO.Exceptions) {
708  if (!LO.Borland && !LO.MicrosoftExt)
709  return nullptr;
710  if (!currentFunctionUsesSEHTry())
711  return nullptr;
712  }
713 
714  // CUDA device code doesn't have exceptions.
715  if (LO.CUDA && LO.CUDAIsDevice)
716  return nullptr;
717 
718  // Check the innermost scope for a cached landing pad. If this is
719  // a non-EH cleanup, we'll check enclosing scopes in EmitLandingPad.
720  llvm::BasicBlock *LP = EHStack.begin()->getCachedLandingPad();
721  if (LP) return LP;
722 
723  const EHPersonality &Personality = EHPersonality::get(*this);
724 
725  if (!CurFn->hasPersonalityFn())
726  CurFn->setPersonalityFn(getOpaquePersonalityFn(CGM, Personality));
727 
728  if (Personality.usesFuncletPads()) {
729  // We don't need separate landing pads in the funclet model.
730  LP = getEHDispatchBlock(EHStack.getInnermostEHScope());
731  } else {
732  // Build the landing pad for this scope.
733  LP = EmitLandingPad();
734  }
735 
736  assert(LP);
737 
738  // Cache the landing pad on the innermost scope. If this is a
739  // non-EH scope, cache the landing pad on the enclosing scope, too.
740  for (EHScopeStack::iterator ir = EHStack.begin(); true; ++ir) {
741  ir->setCachedLandingPad(LP);
742  if (!isNonEHScope(*ir)) break;
743  }
744 
745  return LP;
746 }
747 
748 llvm::BasicBlock *CodeGenFunction::EmitLandingPad() {
749  assert(EHStack.requiresLandingPad());
750 
751  EHScope &innermostEHScope = *EHStack.find(EHStack.getInnermostEHScope());
752  switch (innermostEHScope.getKind()) {
753  case EHScope::Terminate:
754  return getTerminateLandingPad();
755 
756  case EHScope::PadEnd:
757  llvm_unreachable("PadEnd unnecessary for Itanium!");
758 
759  case EHScope::Catch:
760  case EHScope::Cleanup:
761  case EHScope::Filter:
762  if (llvm::BasicBlock *lpad = innermostEHScope.getCachedLandingPad())
763  return lpad;
764  }
765 
766  // Save the current IR generation state.
767  CGBuilderTy::InsertPoint savedIP = Builder.saveAndClearIP();
768  auto DL = ApplyDebugLocation::CreateDefaultArtificial(*this, CurEHLocation);
769 
770  // Create and configure the landing pad.
771  llvm::BasicBlock *lpad = createBasicBlock("lpad");
772  EmitBlock(lpad);
773 
774  llvm::LandingPadInst *LPadInst =
775  Builder.CreateLandingPad(llvm::StructType::get(Int8PtrTy, Int32Ty), 0);
776 
777  llvm::Value *LPadExn = Builder.CreateExtractValue(LPadInst, 0);
778  Builder.CreateStore(LPadExn, getExceptionSlot());
779  llvm::Value *LPadSel = Builder.CreateExtractValue(LPadInst, 1);
780  Builder.CreateStore(LPadSel, getEHSelectorSlot());
781 
782  // Save the exception pointer. It's safe to use a single exception
783  // pointer per function because EH cleanups can never have nested
784  // try/catches.
785  // Build the landingpad instruction.
786 
787  // Accumulate all the handlers in scope.
788  bool hasCatchAll = false;
789  bool hasCleanup = false;
790  bool hasFilter = false;
791  SmallVector<llvm::Value*, 4> filterTypes;
792  llvm::SmallPtrSet<llvm::Value*, 4> catchTypes;
793  for (EHScopeStack::iterator I = EHStack.begin(), E = EHStack.end(); I != E;
794  ++I) {
795 
796  switch (I->getKind()) {
797  case EHScope::Cleanup:
798  // If we have a cleanup, remember that.
799  hasCleanup = (hasCleanup || cast<EHCleanupScope>(*I).isEHCleanup());
800  continue;
801 
802  case EHScope::Filter: {
803  assert(I.next() == EHStack.end() && "EH filter is not end of EH stack");
804  assert(!hasCatchAll && "EH filter reached after catch-all");
805 
806  // Filter scopes get added to the landingpad in weird ways.
807  EHFilterScope &filter = cast<EHFilterScope>(*I);
808  hasFilter = true;
809 
810  // Add all the filter values.
811  for (unsigned i = 0, e = filter.getNumFilters(); i != e; ++i)
812  filterTypes.push_back(filter.getFilter(i));
813  goto done;
814  }
815 
816  case EHScope::Terminate:
817  // Terminate scopes are basically catch-alls.
818  assert(!hasCatchAll);
819  hasCatchAll = true;
820  goto done;
821 
822  case EHScope::Catch:
823  break;
824 
825  case EHScope::PadEnd:
826  llvm_unreachable("PadEnd unnecessary for Itanium!");
827  }
828 
829  EHCatchScope &catchScope = cast<EHCatchScope>(*I);
830  for (unsigned hi = 0, he = catchScope.getNumHandlers(); hi != he; ++hi) {
831  EHCatchScope::Handler handler = catchScope.getHandler(hi);
832  assert(handler.Type.Flags == 0 &&
833  "landingpads do not support catch handler flags");
834 
835  // If this is a catch-all, register that and abort.
836  if (!handler.Type.RTTI) {
837  assert(!hasCatchAll);
838  hasCatchAll = true;
839  goto done;
840  }
841 
842  // Check whether we already have a handler for this type.
843  if (catchTypes.insert(handler.Type.RTTI).second)
844  // If not, add it directly to the landingpad.
845  LPadInst->addClause(handler.Type.RTTI);
846  }
847  }
848 
849  done:
850  // If we have a catch-all, add null to the landingpad.
851  assert(!(hasCatchAll && hasFilter));
852  if (hasCatchAll) {
853  LPadInst->addClause(getCatchAllValue(*this));
854 
855  // If we have an EH filter, we need to add those handlers in the
856  // right place in the landingpad, which is to say, at the end.
857  } else if (hasFilter) {
858  // Create a filter expression: a constant array indicating which filter
859  // types there are. The personality routine only lands here if the filter
860  // doesn't match.
862  llvm::ArrayType *AType =
863  llvm::ArrayType::get(!filterTypes.empty() ?
864  filterTypes[0]->getType() : Int8PtrTy,
865  filterTypes.size());
866 
867  for (unsigned i = 0, e = filterTypes.size(); i != e; ++i)
868  Filters.push_back(cast<llvm::Constant>(filterTypes[i]));
869  llvm::Constant *FilterArray = llvm::ConstantArray::get(AType, Filters);
870  LPadInst->addClause(FilterArray);
871 
872  // Also check whether we need a cleanup.
873  if (hasCleanup)
874  LPadInst->setCleanup(true);
875 
876  // Otherwise, signal that we at least have cleanups.
877  } else if (hasCleanup) {
878  LPadInst->setCleanup(true);
879  }
880 
881  assert((LPadInst->getNumClauses() > 0 || LPadInst->isCleanup()) &&
882  "landingpad instruction has no clauses!");
883 
884  // Tell the backend how to generate the landing pad.
885  Builder.CreateBr(getEHDispatchBlock(EHStack.getInnermostEHScope()));
886 
887  // Restore the old IR generation state.
888  Builder.restoreIP(savedIP);
889 
890  return lpad;
891 }
892 
893 static void emitCatchPadBlock(CodeGenFunction &CGF, EHCatchScope &CatchScope) {
894  llvm::BasicBlock *DispatchBlock = CatchScope.getCachedEHDispatchBlock();
895  assert(DispatchBlock);
896 
897  CGBuilderTy::InsertPoint SavedIP = CGF.Builder.saveIP();
898  CGF.EmitBlockAfterUses(DispatchBlock);
899 
900  llvm::Value *ParentPad = CGF.CurrentFuncletPad;
901  if (!ParentPad)
902  ParentPad = llvm::ConstantTokenNone::get(CGF.getLLVMContext());
903  llvm::BasicBlock *UnwindBB =
904  CGF.getEHDispatchBlock(CatchScope.getEnclosingEHScope());
905 
906  unsigned NumHandlers = CatchScope.getNumHandlers();
907  llvm::CatchSwitchInst *CatchSwitch =
908  CGF.Builder.CreateCatchSwitch(ParentPad, UnwindBB, NumHandlers);
909 
910  // Test against each of the exception types we claim to catch.
911  for (unsigned I = 0; I < NumHandlers; ++I) {
912  const EHCatchScope::Handler &Handler = CatchScope.getHandler(I);
913 
914  CatchTypeInfo TypeInfo = Handler.Type;
915  if (!TypeInfo.RTTI)
916  TypeInfo.RTTI = llvm::Constant::getNullValue(CGF.VoidPtrTy);
917 
918  CGF.Builder.SetInsertPoint(Handler.Block);
919 
920  if (EHPersonality::get(CGF).isMSVCXXPersonality()) {
921  CGF.Builder.CreateCatchPad(
922  CatchSwitch, {TypeInfo.RTTI, CGF.Builder.getInt32(TypeInfo.Flags),
923  llvm::Constant::getNullValue(CGF.VoidPtrTy)});
924  } else {
925  CGF.Builder.CreateCatchPad(CatchSwitch, {TypeInfo.RTTI});
926  }
927 
928  CatchSwitch->addHandler(Handler.Block);
929  }
930  CGF.Builder.restoreIP(SavedIP);
931 }
932 
933 /// Emit the structure of the dispatch block for the given catch scope.
934 /// It is an invariant that the dispatch block already exists.
936  EHCatchScope &catchScope) {
937  if (EHPersonality::get(CGF).usesFuncletPads())
938  return emitCatchPadBlock(CGF, catchScope);
939 
940  llvm::BasicBlock *dispatchBlock = catchScope.getCachedEHDispatchBlock();
941  assert(dispatchBlock);
942 
943  // If there's only a single catch-all, getEHDispatchBlock returned
944  // that catch-all as the dispatch block.
945  if (catchScope.getNumHandlers() == 1 &&
946  catchScope.getHandler(0).isCatchAll()) {
947  assert(dispatchBlock == catchScope.getHandler(0).Block);
948  return;
949  }
950 
951  CGBuilderTy::InsertPoint savedIP = CGF.Builder.saveIP();
952  CGF.EmitBlockAfterUses(dispatchBlock);
953 
954  // Select the right handler.
955  llvm::Value *llvm_eh_typeid_for =
956  CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_typeid_for);
957 
958  // Load the selector value.
959  llvm::Value *selector = CGF.getSelectorFromSlot();
960 
961  // Test against each of the exception types we claim to catch.
962  for (unsigned i = 0, e = catchScope.getNumHandlers(); ; ++i) {
963  assert(i < e && "ran off end of handlers!");
964  const EHCatchScope::Handler &handler = catchScope.getHandler(i);
965 
966  llvm::Value *typeValue = handler.Type.RTTI;
967  assert(handler.Type.Flags == 0 &&
968  "landingpads do not support catch handler flags");
969  assert(typeValue && "fell into catch-all case!");
970  typeValue = CGF.Builder.CreateBitCast(typeValue, CGF.Int8PtrTy);
971 
972  // Figure out the next block.
973  bool nextIsEnd;
974  llvm::BasicBlock *nextBlock;
975 
976  // If this is the last handler, we're at the end, and the next
977  // block is the block for the enclosing EH scope.
978  if (i + 1 == e) {
979  nextBlock = CGF.getEHDispatchBlock(catchScope.getEnclosingEHScope());
980  nextIsEnd = true;
981 
982  // If the next handler is a catch-all, we're at the end, and the
983  // next block is that handler.
984  } else if (catchScope.getHandler(i+1).isCatchAll()) {
985  nextBlock = catchScope.getHandler(i+1).Block;
986  nextIsEnd = true;
987 
988  // Otherwise, we're not at the end and we need a new block.
989  } else {
990  nextBlock = CGF.createBasicBlock("catch.fallthrough");
991  nextIsEnd = false;
992  }
993 
994  // Figure out the catch type's index in the LSDA's type table.
995  llvm::CallInst *typeIndex =
996  CGF.Builder.CreateCall(llvm_eh_typeid_for, typeValue);
997  typeIndex->setDoesNotThrow();
998 
999  llvm::Value *matchesTypeIndex =
1000  CGF.Builder.CreateICmpEQ(selector, typeIndex, "matches");
1001  CGF.Builder.CreateCondBr(matchesTypeIndex, handler.Block, nextBlock);
1002 
1003  // If the next handler is a catch-all, we're completely done.
1004  if (nextIsEnd) {
1005  CGF.Builder.restoreIP(savedIP);
1006  return;
1007  }
1008  // Otherwise we need to emit and continue at that block.
1009  CGF.EmitBlock(nextBlock);
1010  }
1011 }
1012 
1014  EHCatchScope &catchScope = cast<EHCatchScope>(*EHStack.begin());
1015  if (catchScope.hasEHBranches())
1016  emitCatchDispatchBlock(*this, catchScope);
1017  EHStack.popCatch();
1018 }
1019 
1020 void CodeGenFunction::ExitCXXTryStmt(const CXXTryStmt &S, bool IsFnTryBlock) {
1021  unsigned NumHandlers = S.getNumHandlers();
1022  EHCatchScope &CatchScope = cast<EHCatchScope>(*EHStack.begin());
1023  assert(CatchScope.getNumHandlers() == NumHandlers);
1024 
1025  // If the catch was not required, bail out now.
1026  if (!CatchScope.hasEHBranches()) {
1027  CatchScope.clearHandlerBlocks();
1028  EHStack.popCatch();
1029  return;
1030  }
1031 
1032  // Emit the structure of the EH dispatch for this catch.
1033  emitCatchDispatchBlock(*this, CatchScope);
1034 
1035  // Copy the handler blocks off before we pop the EH stack. Emitting
1036  // the handlers might scribble on this memory.
1038  CatchScope.begin(), CatchScope.begin() + NumHandlers);
1039 
1040  EHStack.popCatch();
1041 
1042  // The fall-through block.
1043  llvm::BasicBlock *ContBB = createBasicBlock("try.cont");
1044 
1045  // We just emitted the body of the try; jump to the continue block.
1046  if (HaveInsertPoint())
1047  Builder.CreateBr(ContBB);
1048 
1049  // Determine if we need an implicit rethrow for all these catch handlers;
1050  // see the comment below.
1051  bool doImplicitRethrow = false;
1052  if (IsFnTryBlock)
1053  doImplicitRethrow = isa<CXXDestructorDecl>(CurCodeDecl) ||
1054  isa<CXXConstructorDecl>(CurCodeDecl);
1055 
1056  // Perversely, we emit the handlers backwards precisely because we
1057  // want them to appear in source order. In all of these cases, the
1058  // catch block will have exactly one predecessor, which will be a
1059  // particular block in the catch dispatch. However, in the case of
1060  // a catch-all, one of the dispatch blocks will branch to two
1061  // different handlers, and EmitBlockAfterUses will cause the second
1062  // handler to be moved before the first.
1063  for (unsigned I = NumHandlers; I != 0; --I) {
1064  llvm::BasicBlock *CatchBlock = Handlers[I-1].Block;
1065  EmitBlockAfterUses(CatchBlock);
1066 
1067  // Catch the exception if this isn't a catch-all.
1068  const CXXCatchStmt *C = S.getHandler(I-1);
1069 
1070  // Enter a cleanup scope, including the catch variable and the
1071  // end-catch.
1072  RunCleanupsScope CatchScope(*this);
1073 
1074  // Initialize the catch variable and set up the cleanups.
1075  SaveAndRestore<llvm::Instruction *> RestoreCurrentFuncletPad(
1076  CurrentFuncletPad);
1077  CGM.getCXXABI().emitBeginCatch(*this, C);
1078 
1079  // Emit the PGO counter increment.
1080  incrementProfileCounter(C);
1081 
1082  // Perform the body of the catch.
1083  EmitStmt(C->getHandlerBlock());
1084 
1085  // [except.handle]p11:
1086  // The currently handled exception is rethrown if control
1087  // reaches the end of a handler of the function-try-block of a
1088  // constructor or destructor.
1089 
1090  // It is important that we only do this on fallthrough and not on
1091  // return. Note that it's illegal to put a return in a
1092  // constructor function-try-block's catch handler (p14), so this
1093  // really only applies to destructors.
1094  if (doImplicitRethrow && HaveInsertPoint()) {
1095  CGM.getCXXABI().emitRethrow(*this, /*isNoReturn*/false);
1096  Builder.CreateUnreachable();
1097  Builder.ClearInsertionPoint();
1098  }
1099 
1100  // Fall out through the catch cleanups.
1101  CatchScope.ForceCleanup();
1102 
1103  // Branch out of the try.
1104  if (HaveInsertPoint())
1105  Builder.CreateBr(ContBB);
1106  }
1107 
1108  EmitBlock(ContBB);
1109  incrementProfileCounter(&S);
1110 }
1111 
1112 namespace {
1113  struct CallEndCatchForFinally final : EHScopeStack::Cleanup {
1114  llvm::Value *ForEHVar;
1115  llvm::Value *EndCatchFn;
1116  CallEndCatchForFinally(llvm::Value *ForEHVar, llvm::Value *EndCatchFn)
1117  : ForEHVar(ForEHVar), EndCatchFn(EndCatchFn) {}
1118 
1119  void Emit(CodeGenFunction &CGF, Flags flags) override {
1120  llvm::BasicBlock *EndCatchBB = CGF.createBasicBlock("finally.endcatch");
1121  llvm::BasicBlock *CleanupContBB =
1122  CGF.createBasicBlock("finally.cleanup.cont");
1123 
1124  llvm::Value *ShouldEndCatch =
1125  CGF.Builder.CreateFlagLoad(ForEHVar, "finally.endcatch");
1126  CGF.Builder.CreateCondBr(ShouldEndCatch, EndCatchBB, CleanupContBB);
1127  CGF.EmitBlock(EndCatchBB);
1128  CGF.EmitRuntimeCallOrInvoke(EndCatchFn); // catch-all, so might throw
1129  CGF.EmitBlock(CleanupContBB);
1130  }
1131  };
1132 
1133  struct PerformFinally final : EHScopeStack::Cleanup {
1134  const Stmt *Body;
1135  llvm::Value *ForEHVar;
1136  llvm::Value *EndCatchFn;
1137  llvm::Value *RethrowFn;
1138  llvm::Value *SavedExnVar;
1139 
1140  PerformFinally(const Stmt *Body, llvm::Value *ForEHVar,
1141  llvm::Value *EndCatchFn,
1142  llvm::Value *RethrowFn, llvm::Value *SavedExnVar)
1143  : Body(Body), ForEHVar(ForEHVar), EndCatchFn(EndCatchFn),
1144  RethrowFn(RethrowFn), SavedExnVar(SavedExnVar) {}
1145 
1146  void Emit(CodeGenFunction &CGF, Flags flags) override {
1147  // Enter a cleanup to call the end-catch function if one was provided.
1148  if (EndCatchFn)
1149  CGF.EHStack.pushCleanup<CallEndCatchForFinally>(NormalAndEHCleanup,
1150  ForEHVar, EndCatchFn);
1151 
1152  // Save the current cleanup destination in case there are
1153  // cleanups in the finally block.
1154  llvm::Value *SavedCleanupDest =
1156  "cleanup.dest.saved");
1157 
1158  // Emit the finally block.
1159  CGF.EmitStmt(Body);
1160 
1161  // If the end of the finally is reachable, check whether this was
1162  // for EH. If so, rethrow.
1163  if (CGF.HaveInsertPoint()) {
1164  llvm::BasicBlock *RethrowBB = CGF.createBasicBlock("finally.rethrow");
1165  llvm::BasicBlock *ContBB = CGF.createBasicBlock("finally.cont");
1166 
1167  llvm::Value *ShouldRethrow =
1168  CGF.Builder.CreateFlagLoad(ForEHVar, "finally.shouldthrow");
1169  CGF.Builder.CreateCondBr(ShouldRethrow, RethrowBB, ContBB);
1170 
1171  CGF.EmitBlock(RethrowBB);
1172  if (SavedExnVar) {
1173  CGF.EmitRuntimeCallOrInvoke(RethrowFn,
1174  CGF.Builder.CreateAlignedLoad(SavedExnVar, CGF.getPointerAlign()));
1175  } else {
1176  CGF.EmitRuntimeCallOrInvoke(RethrowFn);
1177  }
1178  CGF.Builder.CreateUnreachable();
1179 
1180  CGF.EmitBlock(ContBB);
1181 
1182  // Restore the cleanup destination.
1183  CGF.Builder.CreateStore(SavedCleanupDest,
1184  CGF.getNormalCleanupDestSlot());
1185  }
1186 
1187  // Leave the end-catch cleanup. As an optimization, pretend that
1188  // the fallthrough path was inaccessible; we've dynamically proven
1189  // that we're not in the EH case along that path.
1190  if (EndCatchFn) {
1191  CGBuilderTy::InsertPoint SavedIP = CGF.Builder.saveAndClearIP();
1192  CGF.PopCleanupBlock();
1193  CGF.Builder.restoreIP(SavedIP);
1194  }
1195 
1196  // Now make sure we actually have an insertion point or the
1197  // cleanup gods will hate us.
1198  CGF.EnsureInsertPoint();
1199  }
1200  };
1201 } // end anonymous namespace
1202 
1203 /// Enters a finally block for an implementation using zero-cost
1204 /// exceptions. This is mostly general, but hard-codes some
1205 /// language/ABI-specific behavior in the catch-all sections.
1207  const Stmt *body,
1208  llvm::Constant *beginCatchFn,
1209  llvm::Constant *endCatchFn,
1210  llvm::Constant *rethrowFn) {
1211  assert((beginCatchFn != nullptr) == (endCatchFn != nullptr) &&
1212  "begin/end catch functions not paired");
1213  assert(rethrowFn && "rethrow function is required");
1214 
1215  BeginCatchFn = beginCatchFn;
1216 
1217  // The rethrow function has one of the following two types:
1218  // void (*)()
1219  // void (*)(void*)
1220  // In the latter case we need to pass it the exception object.
1221  // But we can't use the exception slot because the @finally might
1222  // have a landing pad (which would overwrite the exception slot).
1223  llvm::FunctionType *rethrowFnTy =
1224  cast<llvm::FunctionType>(
1225  cast<llvm::PointerType>(rethrowFn->getType())->getElementType());
1226  SavedExnVar = nullptr;
1227  if (rethrowFnTy->getNumParams())
1228  SavedExnVar = CGF.CreateTempAlloca(CGF.Int8PtrTy, "finally.exn");
1229 
1230  // A finally block is a statement which must be executed on any edge
1231  // out of a given scope. Unlike a cleanup, the finally block may
1232  // contain arbitrary control flow leading out of itself. In
1233  // addition, finally blocks should always be executed, even if there
1234  // are no catch handlers higher on the stack. Therefore, we
1235  // surround the protected scope with a combination of a normal
1236  // cleanup (to catch attempts to break out of the block via normal
1237  // control flow) and an EH catch-all (semantically "outside" any try
1238  // statement to which the finally block might have been attached).
1239  // The finally block itself is generated in the context of a cleanup
1240  // which conditionally leaves the catch-all.
1241 
1242  // Jump destination for performing the finally block on an exception
1243  // edge. We'll never actually reach this block, so unreachable is
1244  // fine.
1245  RethrowDest = CGF.getJumpDestInCurrentScope(CGF.getUnreachableBlock());
1246 
1247  // Whether the finally block is being executed for EH purposes.
1248  ForEHVar = CGF.CreateTempAlloca(CGF.Builder.getInt1Ty(), "finally.for-eh");
1249  CGF.Builder.CreateFlagStore(false, ForEHVar);
1250 
1251  // Enter a normal cleanup which will perform the @finally block.
1252  CGF.EHStack.pushCleanup<PerformFinally>(NormalCleanup, body,
1253  ForEHVar, endCatchFn,
1254  rethrowFn, SavedExnVar);
1255 
1256  // Enter a catch-all scope.
1257  llvm::BasicBlock *catchBB = CGF.createBasicBlock("finally.catchall");
1258  EHCatchScope *catchScope = CGF.EHStack.pushCatch(1);
1259  catchScope->setCatchAllHandler(0, catchBB);
1260 }
1261 
1263  // Leave the finally catch-all.
1264  EHCatchScope &catchScope = cast<EHCatchScope>(*CGF.EHStack.begin());
1265  llvm::BasicBlock *catchBB = catchScope.getHandler(0).Block;
1266 
1267  CGF.popCatchScope();
1268 
1269  // If there are any references to the catch-all block, emit it.
1270  if (catchBB->use_empty()) {
1271  delete catchBB;
1272  } else {
1273  CGBuilderTy::InsertPoint savedIP = CGF.Builder.saveAndClearIP();
1274  CGF.EmitBlock(catchBB);
1275 
1276  llvm::Value *exn = nullptr;
1277 
1278  // If there's a begin-catch function, call it.
1279  if (BeginCatchFn) {
1280  exn = CGF.getExceptionFromSlot();
1281  CGF.EmitNounwindRuntimeCall(BeginCatchFn, exn);
1282  }
1283 
1284  // If we need to remember the exception pointer to rethrow later, do so.
1285  if (SavedExnVar) {
1286  if (!exn) exn = CGF.getExceptionFromSlot();
1287  CGF.Builder.CreateAlignedStore(exn, SavedExnVar, CGF.getPointerAlign());
1288  }
1289 
1290  // Tell the cleanups in the finally block that we're do this for EH.
1291  CGF.Builder.CreateFlagStore(true, ForEHVar);
1292 
1293  // Thread a jump through the finally cleanup.
1294  CGF.EmitBranchThroughCleanup(RethrowDest);
1295 
1296  CGF.Builder.restoreIP(savedIP);
1297  }
1298 
1299  // Finally, leave the @finally cleanup.
1300  CGF.PopCleanupBlock();
1301 }
1302 
1304  if (TerminateLandingPad)
1305  return TerminateLandingPad;
1306 
1307  CGBuilderTy::InsertPoint SavedIP = Builder.saveAndClearIP();
1308 
1309  // This will get inserted at the end of the function.
1310  TerminateLandingPad = createBasicBlock("terminate.lpad");
1311  Builder.SetInsertPoint(TerminateLandingPad);
1312 
1313  // Tell the backend that this is a landing pad.
1314  const EHPersonality &Personality = EHPersonality::get(*this);
1315 
1316  if (!CurFn->hasPersonalityFn())
1317  CurFn->setPersonalityFn(getOpaquePersonalityFn(CGM, Personality));
1318 
1319  llvm::LandingPadInst *LPadInst =
1320  Builder.CreateLandingPad(llvm::StructType::get(Int8PtrTy, Int32Ty), 0);
1321  LPadInst->addClause(getCatchAllValue(*this));
1322 
1323  llvm::Value *Exn = nullptr;
1324  if (getLangOpts().CPlusPlus)
1325  Exn = Builder.CreateExtractValue(LPadInst, 0);
1326  llvm::CallInst *terminateCall =
1327  CGM.getCXXABI().emitTerminateForUnexpectedException(*this, Exn);
1328  terminateCall->setDoesNotReturn();
1329  Builder.CreateUnreachable();
1330 
1331  // Restore the saved insertion state.
1332  Builder.restoreIP(SavedIP);
1333 
1334  return TerminateLandingPad;
1335 }
1336 
1338  if (TerminateHandler)
1339  return TerminateHandler;
1340 
1341  CGBuilderTy::InsertPoint SavedIP = Builder.saveAndClearIP();
1342 
1343  // Set up the terminate handler. This block is inserted at the very
1344  // end of the function by FinishFunction.
1345  TerminateHandler = createBasicBlock("terminate.handler");
1346  Builder.SetInsertPoint(TerminateHandler);
1347  llvm::Value *Exn = nullptr;
1348  SaveAndRestore<llvm::Instruction *> RestoreCurrentFuncletPad(
1349  CurrentFuncletPad);
1350  if (EHPersonality::get(*this).usesFuncletPads()) {
1351  llvm::Value *ParentPad = CurrentFuncletPad;
1352  if (!ParentPad)
1353  ParentPad = llvm::ConstantTokenNone::get(CGM.getLLVMContext());
1354  CurrentFuncletPad = Builder.CreateCleanupPad(ParentPad);
1355  } else {
1356  if (getLangOpts().CPlusPlus)
1357  Exn = getExceptionFromSlot();
1358  }
1359  llvm::CallInst *terminateCall =
1360  CGM.getCXXABI().emitTerminateForUnexpectedException(*this, Exn);
1361  terminateCall->setDoesNotReturn();
1362  Builder.CreateUnreachable();
1363 
1364  // Restore the saved insertion state.
1365  Builder.restoreIP(SavedIP);
1366 
1367  return TerminateHandler;
1368 }
1369 
1370 llvm::BasicBlock *CodeGenFunction::getEHResumeBlock(bool isCleanup) {
1371  if (EHResumeBlock) return EHResumeBlock;
1372 
1373  CGBuilderTy::InsertPoint SavedIP = Builder.saveIP();
1374 
1375  // We emit a jump to a notional label at the outermost unwind state.
1376  EHResumeBlock = createBasicBlock("eh.resume");
1377  Builder.SetInsertPoint(EHResumeBlock);
1378 
1379  const EHPersonality &Personality = EHPersonality::get(*this);
1380 
1381  // This can always be a call because we necessarily didn't find
1382  // anything on the EH stack which needs our help.
1383  const char *RethrowName = Personality.CatchallRethrowFn;
1384  if (RethrowName != nullptr && !isCleanup) {
1385  EmitRuntimeCall(getCatchallRethrowFn(CGM, RethrowName),
1386  getExceptionFromSlot())->setDoesNotReturn();
1387  Builder.CreateUnreachable();
1388  Builder.restoreIP(SavedIP);
1389  return EHResumeBlock;
1390  }
1391 
1392  // Recreate the landingpad's return value for the 'resume' instruction.
1393  llvm::Value *Exn = getExceptionFromSlot();
1394  llvm::Value *Sel = getSelectorFromSlot();
1395 
1396  llvm::Type *LPadType = llvm::StructType::get(Exn->getType(), Sel->getType());
1397  llvm::Value *LPadVal = llvm::UndefValue::get(LPadType);
1398  LPadVal = Builder.CreateInsertValue(LPadVal, Exn, 0, "lpad.val");
1399  LPadVal = Builder.CreateInsertValue(LPadVal, Sel, 1, "lpad.val");
1400 
1401  Builder.CreateResume(LPadVal);
1402  Builder.restoreIP(SavedIP);
1403  return EHResumeBlock;
1404 }
1405 
1407  EnterSEHTryStmt(S);
1408  {
1409  JumpDest TryExit = getJumpDestInCurrentScope("__try.__leave");
1410 
1411  SEHTryEpilogueStack.push_back(&TryExit);
1412  EmitStmt(S.getTryBlock());
1413  SEHTryEpilogueStack.pop_back();
1414 
1415  if (!TryExit.getBlock()->use_empty())
1416  EmitBlock(TryExit.getBlock(), /*IsFinished=*/true);
1417  else
1418  delete TryExit.getBlock();
1419  }
1420  ExitSEHTryStmt(S);
1421 }
1422 
1423 namespace {
1424 struct PerformSEHFinally final : EHScopeStack::Cleanup {
1425  llvm::Function *OutlinedFinally;
1426  PerformSEHFinally(llvm::Function *OutlinedFinally)
1427  : OutlinedFinally(OutlinedFinally) {}
1428 
1429  void Emit(CodeGenFunction &CGF, Flags F) override {
1430  ASTContext &Context = CGF.getContext();
1431  CodeGenModule &CGM = CGF.CGM;
1432 
1433  CallArgList Args;
1434 
1435  // Compute the two argument values.
1436  QualType ArgTys[2] = {Context.UnsignedCharTy, Context.VoidPtrTy};
1437  llvm::Value *LocalAddrFn = CGM.getIntrinsic(llvm::Intrinsic::localaddress);
1438  llvm::Value *FP = CGF.Builder.CreateCall(LocalAddrFn);
1439  llvm::Value *IsForEH =
1440  llvm::ConstantInt::get(CGF.ConvertType(ArgTys[0]), F.isForEHCleanup());
1441  Args.add(RValue::get(IsForEH), ArgTys[0]);
1442  Args.add(RValue::get(FP), ArgTys[1]);
1443 
1444  // Arrange a two-arg function info and type.
1445  const CGFunctionInfo &FnInfo =
1446  CGM.getTypes().arrangeBuiltinFunctionCall(Context.VoidTy, Args);
1447 
1448  auto Callee = CGCallee::forDirect(OutlinedFinally);
1449  CGF.EmitCall(FnInfo, Callee, ReturnValueSlot(), Args);
1450  }
1451 };
1452 } // end anonymous namespace
1453 
1454 namespace {
1455 /// Find all local variable captures in the statement.
1456 struct CaptureFinder : ConstStmtVisitor<CaptureFinder> {
1457  CodeGenFunction &ParentCGF;
1458  const VarDecl *ParentThis;
1460  Address SEHCodeSlot = Address::invalid();
1461  CaptureFinder(CodeGenFunction &ParentCGF, const VarDecl *ParentThis)
1462  : ParentCGF(ParentCGF), ParentThis(ParentThis) {}
1463 
1464  // Return true if we need to do any capturing work.
1465  bool foundCaptures() {
1466  return !Captures.empty() || SEHCodeSlot.isValid();
1467  }
1468 
1469  void Visit(const Stmt *S) {
1470  // See if this is a capture, then recurse.
1472  for (const Stmt *Child : S->children())
1473  if (Child)
1474  Visit(Child);
1475  }
1476 
1477  void VisitDeclRefExpr(const DeclRefExpr *E) {
1478  // If this is already a capture, just make sure we capture 'this'.
1480  Captures.insert(ParentThis);
1481  return;
1482  }
1483 
1484  const auto *D = dyn_cast<VarDecl>(E->getDecl());
1485  if (D && D->isLocalVarDeclOrParm() && D->hasLocalStorage())
1486  Captures.insert(D);
1487  }
1488 
1489  void VisitCXXThisExpr(const CXXThisExpr *E) {
1490  Captures.insert(ParentThis);
1491  }
1492 
1493  void VisitCallExpr(const CallExpr *E) {
1494  // We only need to add parent frame allocations for these builtins in x86.
1495  if (ParentCGF.getTarget().getTriple().getArch() != llvm::Triple::x86)
1496  return;
1497 
1498  unsigned ID = E->getBuiltinCallee();
1499  switch (ID) {
1500  case Builtin::BI__exception_code:
1501  case Builtin::BI_exception_code:
1502  // This is the simple case where we are the outermost finally. All we
1503  // have to do here is make sure we escape this and recover it in the
1504  // outlined handler.
1505  if (!SEHCodeSlot.isValid())
1506  SEHCodeSlot = ParentCGF.SEHCodeSlotStack.back();
1507  break;
1508  }
1509  }
1510 };
1511 } // end anonymous namespace
1512 
1514  Address ParentVar,
1515  llvm::Value *ParentFP) {
1516  llvm::CallInst *RecoverCall = nullptr;
1517  CGBuilderTy Builder(*this, AllocaInsertPt);
1518  if (auto *ParentAlloca = dyn_cast<llvm::AllocaInst>(ParentVar.getPointer())) {
1519  // Mark the variable escaped if nobody else referenced it and compute the
1520  // localescape index.
1521  auto InsertPair = ParentCGF.EscapedLocals.insert(
1522  std::make_pair(ParentAlloca, ParentCGF.EscapedLocals.size()));
1523  int FrameEscapeIdx = InsertPair.first->second;
1524  // call i8* @llvm.localrecover(i8* bitcast(@parentFn), i8* %fp, i32 N)
1525  llvm::Function *FrameRecoverFn = llvm::Intrinsic::getDeclaration(
1526  &CGM.getModule(), llvm::Intrinsic::localrecover);
1527  llvm::Constant *ParentI8Fn =
1528  llvm::ConstantExpr::getBitCast(ParentCGF.CurFn, Int8PtrTy);
1529  RecoverCall = Builder.CreateCall(
1530  FrameRecoverFn, {ParentI8Fn, ParentFP,
1531  llvm::ConstantInt::get(Int32Ty, FrameEscapeIdx)});
1532 
1533  } else {
1534  // If the parent didn't have an alloca, we're doing some nested outlining.
1535  // Just clone the existing localrecover call, but tweak the FP argument to
1536  // use our FP value. All other arguments are constants.
1537  auto *ParentRecover =
1538  cast<llvm::IntrinsicInst>(ParentVar.getPointer()->stripPointerCasts());
1539  assert(ParentRecover->getIntrinsicID() == llvm::Intrinsic::localrecover &&
1540  "expected alloca or localrecover in parent LocalDeclMap");
1541  RecoverCall = cast<llvm::CallInst>(ParentRecover->clone());
1542  RecoverCall->setArgOperand(1, ParentFP);
1543  RecoverCall->insertBefore(AllocaInsertPt);
1544  }
1545 
1546  // Bitcast the variable, rename it, and insert it in the local decl map.
1547  llvm::Value *ChildVar =
1548  Builder.CreateBitCast(RecoverCall, ParentVar.getType());
1549  ChildVar->setName(ParentVar.getName());
1550  return Address(ChildVar, ParentVar.getAlignment());
1551 }
1552 
1554  const Stmt *OutlinedStmt,
1555  bool IsFilter) {
1556  // Find all captures in the Stmt.
1557  CaptureFinder Finder(ParentCGF, ParentCGF.CXXABIThisDecl);
1558  Finder.Visit(OutlinedStmt);
1559 
1560  // We can exit early on x86_64 when there are no captures. We just have to
1561  // save the exception code in filters so that __exception_code() works.
1562  if (!Finder.foundCaptures() &&
1563  CGM.getTarget().getTriple().getArch() != llvm::Triple::x86) {
1564  if (IsFilter)
1565  EmitSEHExceptionCodeSave(ParentCGF, nullptr, nullptr);
1566  return;
1567  }
1568 
1569  llvm::Value *EntryFP = nullptr;
1570  CGBuilderTy Builder(CGM, AllocaInsertPt);
1571  if (IsFilter && CGM.getTarget().getTriple().getArch() == llvm::Triple::x86) {
1572  // 32-bit SEH filters need to be careful about FP recovery. The end of the
1573  // EH registration is passed in as the EBP physical register. We can
1574  // recover that with llvm.frameaddress(1).
1575  EntryFP = Builder.CreateCall(
1576  CGM.getIntrinsic(llvm::Intrinsic::frameaddress), {Builder.getInt32(1)});
1577  } else {
1578  // Otherwise, for x64 and 32-bit finally functions, the parent FP is the
1579  // second parameter.
1580  auto AI = CurFn->arg_begin();
1581  ++AI;
1582  EntryFP = &*AI;
1583  }
1584 
1585  llvm::Value *ParentFP = EntryFP;
1586  if (IsFilter) {
1587  // Given whatever FP the runtime provided us in EntryFP, recover the true
1588  // frame pointer of the parent function. We only need to do this in filters,
1589  // since finally funclets recover the parent FP for us.
1590  llvm::Function *RecoverFPIntrin =
1591  CGM.getIntrinsic(llvm::Intrinsic::x86_seh_recoverfp);
1592  llvm::Constant *ParentI8Fn =
1593  llvm::ConstantExpr::getBitCast(ParentCGF.CurFn, Int8PtrTy);
1594  ParentFP = Builder.CreateCall(RecoverFPIntrin, {ParentI8Fn, EntryFP});
1595  }
1596 
1597  // Create llvm.localrecover calls for all captures.
1598  for (const VarDecl *VD : Finder.Captures) {
1599  if (isa<ImplicitParamDecl>(VD)) {
1600  CGM.ErrorUnsupported(VD, "'this' captured by SEH");
1601  CXXThisValue = llvm::UndefValue::get(ConvertTypeForMem(VD->getType()));
1602  continue;
1603  }
1604  if (VD->getType()->isVariablyModifiedType()) {
1605  CGM.ErrorUnsupported(VD, "VLA captured by SEH");
1606  continue;
1607  }
1608  assert((isa<ImplicitParamDecl>(VD) || VD->isLocalVarDeclOrParm()) &&
1609  "captured non-local variable");
1610 
1611  // If this decl hasn't been declared yet, it will be declared in the
1612  // OutlinedStmt.
1613  auto I = ParentCGF.LocalDeclMap.find(VD);
1614  if (I == ParentCGF.LocalDeclMap.end())
1615  continue;
1616 
1617  Address ParentVar = I->second;
1618  setAddrOfLocalVar(
1619  VD, recoverAddrOfEscapedLocal(ParentCGF, ParentVar, ParentFP));
1620  }
1621 
1622  if (Finder.SEHCodeSlot.isValid()) {
1623  SEHCodeSlotStack.push_back(
1624  recoverAddrOfEscapedLocal(ParentCGF, Finder.SEHCodeSlot, ParentFP));
1625  }
1626 
1627  if (IsFilter)
1628  EmitSEHExceptionCodeSave(ParentCGF, ParentFP, EntryFP);
1629 }
1630 
1631 /// Arrange a function prototype that can be called by Windows exception
1632 /// handling personalities. On Win64, the prototype looks like:
1633 /// RetTy func(void *EHPtrs, void *ParentFP);
1635  bool IsFilter,
1636  const Stmt *OutlinedStmt) {
1637  SourceLocation StartLoc = OutlinedStmt->getLocStart();
1638 
1639  // Get the mangled function name.
1640  SmallString<128> Name;
1641  {
1642  llvm::raw_svector_ostream OS(Name);
1643  const FunctionDecl *ParentSEHFn = ParentCGF.CurSEHParent;
1644  assert(ParentSEHFn && "No CurSEHParent!");
1645  MangleContext &Mangler = CGM.getCXXABI().getMangleContext();
1646  if (IsFilter)
1647  Mangler.mangleSEHFilterExpression(ParentSEHFn, OS);
1648  else
1649  Mangler.mangleSEHFinallyBlock(ParentSEHFn, OS);
1650  }
1651 
1652  FunctionArgList Args;
1653  if (CGM.getTarget().getTriple().getArch() != llvm::Triple::x86 || !IsFilter) {
1654  // All SEH finally functions take two parameters. Win64 filters take two
1655  // parameters. Win32 filters take no parameters.
1656  if (IsFilter) {
1657  Args.push_back(ImplicitParamDecl::Create(
1658  getContext(), /*DC=*/nullptr, StartLoc,
1659  &getContext().Idents.get("exception_pointers"),
1661  } else {
1662  Args.push_back(ImplicitParamDecl::Create(
1663  getContext(), /*DC=*/nullptr, StartLoc,
1664  &getContext().Idents.get("abnormal_termination"),
1666  }
1667  Args.push_back(ImplicitParamDecl::Create(
1668  getContext(), /*DC=*/nullptr, StartLoc,
1669  &getContext().Idents.get("frame_pointer"), getContext().VoidPtrTy,
1671  }
1672 
1673  QualType RetTy = IsFilter ? getContext().LongTy : getContext().VoidTy;
1674 
1675  const CGFunctionInfo &FnInfo =
1676  CGM.getTypes().arrangeBuiltinFunctionDeclaration(RetTy, Args);
1677 
1678  llvm::FunctionType *FnTy = CGM.getTypes().GetFunctionType(FnInfo);
1679  llvm::Function *Fn = llvm::Function::Create(
1680  FnTy, llvm::GlobalValue::InternalLinkage, Name.str(), &CGM.getModule());
1681 
1682  IsOutlinedSEHHelper = true;
1683 
1684  StartFunction(GlobalDecl(), RetTy, Fn, FnInfo, Args,
1685  OutlinedStmt->getLocStart(), OutlinedStmt->getLocStart());
1686  CurSEHParent = ParentCGF.CurSEHParent;
1687 
1688  CGM.SetLLVMFunctionAttributes(nullptr, FnInfo, CurFn);
1689  EmitCapturedLocals(ParentCGF, OutlinedStmt, IsFilter);
1690 }
1691 
1692 /// Create a stub filter function that will ultimately hold the code of the
1693 /// filter expression. The EH preparation passes in LLVM will outline the code
1694 /// from the main function body into this stub.
1695 llvm::Function *
1697  const SEHExceptStmt &Except) {
1698  const Expr *FilterExpr = Except.getFilterExpr();
1699  startOutlinedSEHHelper(ParentCGF, true, FilterExpr);
1700 
1701  // Emit the original filter expression, convert to i32, and return.
1702  llvm::Value *R = EmitScalarExpr(FilterExpr);
1703  R = Builder.CreateIntCast(R, ConvertType(getContext().LongTy),
1704  FilterExpr->getType()->isSignedIntegerType());
1705  Builder.CreateStore(R, ReturnValue);
1706 
1707  FinishFunction(FilterExpr->getLocEnd());
1708 
1709  return CurFn;
1710 }
1711 
1712 llvm::Function *
1714  const SEHFinallyStmt &Finally) {
1715  const Stmt *FinallyBlock = Finally.getBlock();
1716  startOutlinedSEHHelper(ParentCGF, false, FinallyBlock);
1717 
1718  // Emit the original filter expression, convert to i32, and return.
1719  EmitStmt(FinallyBlock);
1720 
1721  FinishFunction(FinallyBlock->getLocEnd());
1722 
1723  return CurFn;
1724 }
1725 
1727  llvm::Value *ParentFP,
1728  llvm::Value *EntryFP) {
1729  // Get the pointer to the EXCEPTION_POINTERS struct. This is returned by the
1730  // __exception_info intrinsic.
1731  if (CGM.getTarget().getTriple().getArch() != llvm::Triple::x86) {
1732  // On Win64, the info is passed as the first parameter to the filter.
1733  SEHInfo = &*CurFn->arg_begin();
1734  SEHCodeSlotStack.push_back(
1735  CreateMemTemp(getContext().IntTy, "__exception_code"));
1736  } else {
1737  // On Win32, the EBP on entry to the filter points to the end of an
1738  // exception registration object. It contains 6 32-bit fields, and the info
1739  // pointer is stored in the second field. So, GEP 20 bytes backwards and
1740  // load the pointer.
1741  SEHInfo = Builder.CreateConstInBoundsGEP1_32(Int8Ty, EntryFP, -20);
1742  SEHInfo = Builder.CreateBitCast(SEHInfo, Int8PtrTy->getPointerTo());
1743  SEHInfo = Builder.CreateAlignedLoad(Int8PtrTy, SEHInfo, getPointerAlign());
1744  SEHCodeSlotStack.push_back(recoverAddrOfEscapedLocal(
1745  ParentCGF, ParentCGF.SEHCodeSlotStack.back(), ParentFP));
1746  }
1747 
1748  // Save the exception code in the exception slot to unify exception access in
1749  // the filter function and the landing pad.
1750  // struct EXCEPTION_POINTERS {
1751  // EXCEPTION_RECORD *ExceptionRecord;
1752  // CONTEXT *ContextRecord;
1753  // };
1754  // int exceptioncode = exception_pointers->ExceptionRecord->ExceptionCode;
1755  llvm::Type *RecordTy = CGM.Int32Ty->getPointerTo();
1756  llvm::Type *PtrsTy = llvm::StructType::get(RecordTy, CGM.VoidPtrTy);
1757  llvm::Value *Ptrs = Builder.CreateBitCast(SEHInfo, PtrsTy->getPointerTo());
1758  llvm::Value *Rec = Builder.CreateStructGEP(PtrsTy, Ptrs, 0);
1759  Rec = Builder.CreateAlignedLoad(Rec, getPointerAlign());
1760  llvm::Value *Code = Builder.CreateAlignedLoad(Rec, getIntAlign());
1761  assert(!SEHCodeSlotStack.empty() && "emitting EH code outside of __except");
1762  Builder.CreateStore(Code, SEHCodeSlotStack.back());
1763 }
1764 
1766  // Sema should diagnose calling this builtin outside of a filter context, but
1767  // don't crash if we screw up.
1768  if (!SEHInfo)
1769  return llvm::UndefValue::get(Int8PtrTy);
1770  assert(SEHInfo->getType() == Int8PtrTy);
1771  return SEHInfo;
1772 }
1773 
1775  assert(!SEHCodeSlotStack.empty() && "emitting EH code outside of __except");
1776  return Builder.CreateLoad(SEHCodeSlotStack.back());
1777 }
1778 
1780  // Abnormal termination is just the first parameter to the outlined finally
1781  // helper.
1782  auto AI = CurFn->arg_begin();
1783  return Builder.CreateZExt(&*AI, Int32Ty);
1784 }
1785 
1787  CodeGenFunction HelperCGF(CGM, /*suppressNewContext=*/true);
1788  if (const SEHFinallyStmt *Finally = S.getFinallyHandler()) {
1789  // Outline the finally block.
1790  llvm::Function *FinallyFunc =
1791  HelperCGF.GenerateSEHFinallyFunction(*this, *Finally);
1792 
1793  // Push a cleanup for __finally blocks.
1794  EHStack.pushCleanup<PerformSEHFinally>(NormalAndEHCleanup, FinallyFunc);
1795  return;
1796  }
1797 
1798  // Otherwise, we must have an __except block.
1799  const SEHExceptStmt *Except = S.getExceptHandler();
1800  assert(Except);
1801  EHCatchScope *CatchScope = EHStack.pushCatch(1);
1802  SEHCodeSlotStack.push_back(
1803  CreateMemTemp(getContext().IntTy, "__exception_code"));
1804 
1805  // If the filter is known to evaluate to 1, then we can use the clause
1806  // "catch i8* null". We can't do this on x86 because the filter has to save
1807  // the exception code.
1808  llvm::Constant *C =
1810  getContext().IntTy);
1811  if (CGM.getTarget().getTriple().getArch() != llvm::Triple::x86 && C &&
1812  C->isOneValue()) {
1813  CatchScope->setCatchAllHandler(0, createBasicBlock("__except"));
1814  return;
1815  }
1816 
1817  // In general, we have to emit an outlined filter function. Use the function
1818  // in place of the RTTI typeinfo global that C++ EH uses.
1819  llvm::Function *FilterFunc =
1820  HelperCGF.GenerateSEHFilterFunction(*this, *Except);
1821  llvm::Constant *OpaqueFunc =
1822  llvm::ConstantExpr::getBitCast(FilterFunc, Int8PtrTy);
1823  CatchScope->setHandler(0, OpaqueFunc, createBasicBlock("__except.ret"));
1824 }
1825 
1827  // Just pop the cleanup if it's a __finally block.
1828  if (S.getFinallyHandler()) {
1829  PopCleanupBlock();
1830  return;
1831  }
1832 
1833  // Otherwise, we must have an __except block.
1834  const SEHExceptStmt *Except = S.getExceptHandler();
1835  assert(Except && "__try must have __finally xor __except");
1836  EHCatchScope &CatchScope = cast<EHCatchScope>(*EHStack.begin());
1837 
1838  // Don't emit the __except block if the __try block lacked invokes.
1839  // TODO: Model unwind edges from instructions, either with iload / istore or
1840  // a try body function.
1841  if (!CatchScope.hasEHBranches()) {
1842  CatchScope.clearHandlerBlocks();
1843  EHStack.popCatch();
1844  SEHCodeSlotStack.pop_back();
1845  return;
1846  }
1847 
1848  // The fall-through block.
1849  llvm::BasicBlock *ContBB = createBasicBlock("__try.cont");
1850 
1851  // We just emitted the body of the __try; jump to the continue block.
1852  if (HaveInsertPoint())
1853  Builder.CreateBr(ContBB);
1854 
1855  // Check if our filter function returned true.
1856  emitCatchDispatchBlock(*this, CatchScope);
1857 
1858  // Grab the block before we pop the handler.
1859  llvm::BasicBlock *CatchPadBB = CatchScope.getHandler(0).Block;
1860  EHStack.popCatch();
1861 
1862  EmitBlockAfterUses(CatchPadBB);
1863 
1864  // __except blocks don't get outlined into funclets, so immediately do a
1865  // catchret.
1866  llvm::CatchPadInst *CPI =
1867  cast<llvm::CatchPadInst>(CatchPadBB->getFirstNonPHI());
1868  llvm::BasicBlock *ExceptBB = createBasicBlock("__except");
1869  Builder.CreateCatchRet(CPI, ExceptBB);
1870  EmitBlock(ExceptBB);
1871 
1872  // On Win64, the exception code is returned in EAX. Copy it into the slot.
1873  if (CGM.getTarget().getTriple().getArch() != llvm::Triple::x86) {
1874  llvm::Function *SEHCodeIntrin =
1875  CGM.getIntrinsic(llvm::Intrinsic::eh_exceptioncode);
1876  llvm::Value *Code = Builder.CreateCall(SEHCodeIntrin, {CPI});
1877  Builder.CreateStore(Code, SEHCodeSlotStack.back());
1878  }
1879 
1880  // Emit the __except body.
1881  EmitStmt(Except->getBlock());
1882 
1883  // End the lifetime of the exception code.
1884  SEHCodeSlotStack.pop_back();
1885 
1886  if (HaveInsertPoint())
1887  Builder.CreateBr(ContBB);
1888 
1889  EmitBlock(ContBB);
1890 }
1891 
1893  // If this code is reachable then emit a stop point (if generating
1894  // debug info). We have to do this ourselves because we are on the
1895  // "simple" statement path.
1896  if (HaveInsertPoint())
1897  EmitStopPoint(&S);
1898 
1899  // This must be a __leave from a __finally block, which we warn on and is UB.
1900  // Just emit unreachable.
1901  if (!isSEHTryScope()) {
1902  Builder.CreateUnreachable();
1903  Builder.ClearInsertionPoint();
1904  return;
1905  }
1906 
1907  EmitBranchThroughCleanup(*SEHTryEpilogueStack.back());
1908 }
virtual void mangleSEHFilterExpression(const NamedDecl *EnclosingDecl, raw_ostream &Out)=0
ReturnValueSlot - Contains the address where the return value of a function can be stored...
Definition: CGCall.h:281
FunctionDecl - An instance of this class is created to represent a function declaration or definition...
Definition: Decl.h:1631
llvm::IntegerType * IntTy
int
EHScopeStack::stable_iterator getEnclosingEHScope() const
Definition: CGCleanup.h:138
Parameter for captured context.
Definition: Decl.h:1408
CompoundStmt * getBlock() const
Definition: Stmt.h:1936
void setCatchAllHandler(unsigned I, llvm::BasicBlock *Block)
Definition: CGCleanup.h:193
CanQualType VoidPtrTy
Definition: ASTContext.h:981
A (possibly-)qualified type.
Definition: Type.h:614
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
Represents a version number in the form major[.minor[.subminor[.build]]].
Definition: VersionTuple.h:26
unsigned getNumExceptions() const
Definition: Type.h:3456
const Expr * getSubExpr() const
Definition: ExprCXX.h:948
ConstStmtVisitor - This class implements a simple visitor for Stmt subclasses.
Definition: StmtVisitor.h:189
llvm::BasicBlock * getCachedEHDispatchBlock() const
Definition: CGCleanup.h:124
bool HaveInsertPoint() const
HaveInsertPoint - True if an insertion point is defined.
static const EHPersonality GNU_C_SJLJ
Definition: CGCleanup.h:616
void EmitCXXTryStmt(const CXXTryStmt &S)
Stmt - This represents one statement.
Definition: Stmt.h:60
CXXCatchStmt * getHandler(unsigned i)
Definition: StmtCXX.h:104
static const EHPersonality MSVC_C_specific_handler
Definition: CGCleanup.h:628
const llvm::Triple & getTriple() const
Returns the target triple of the primary target.
Definition: TargetInfo.h:782
static const EHPersonality MSVC_CxxFrameHandler3
Definition: CGCleanup.h:629
tooling::Replacements cleanup(const FormatStyle &Style, StringRef Code, ArrayRef< tooling::Range > Ranges, StringRef FileName="<stdin>")
Clean up any erroneous/redundant code in the given Ranges in Code.
Definition: Format.cpp:1969
bool hasEHBranches() const
Definition: CGCleanup.h:132
Decl - This represents one declaration (or definition), e.g.
Definition: DeclBase.h:81
Stmt * getHandlerBlock() const
Definition: StmtCXX.h:52
const Decl * CurCodeDecl
CurCodeDecl - This is the inner-most code context, which includes blocks.
static const EHPersonality GNU_C
Definition: CGCleanup.h:615
virtual void mangleSEHFinallyBlock(const NamedDecl *EnclosingDecl, raw_ostream &Out)=0
QualType getNonReferenceType() const
If Type is a reference type (e.g., const int&), returns the type that the reference refers to ("const...
Definition: Type.h:5716
Represents Objective-C&#39;s @throw statement.
Definition: StmtObjC.h:313
CanQualType LongTy
Definition: ASTContext.h:973
static llvm::Constant * getUnexpectedFn(CodeGenModule &CGM)
Definition: CGException.cpp:42
void EmitSEHExceptionCodeSave(CodeGenFunction &ParentCGF, llvm::Value *ParentFP, llvm::Value *EntryEBP)
bool usesSEHTry() const
Indicates the function uses __try.
Definition: Decl.h:1970
static llvm::Constant * getPersonalityFn(CodeGenModule &CGM, const EHPersonality &Personality)
unsigned getNumFilters() const
Definition: CGCleanup.h:461
llvm::IntegerType * Int8Ty
i8, i16, i32, and i64
&#39;gcc&#39; is the Objective-C runtime shipped with GCC, implementing a fragile Objective-C ABI ...
Definition: ObjCRuntime.h:50
VarDecl - An instance of this class is created to represent a variable declaration or definition...
Definition: Decl.h:771
const T * getAs() const
Member-template getAs<specific type>&#39;.
Definition: Type.h:6099
unsigned getNumHandlers() const
Definition: CGCleanup.h:189
llvm::Value * getPointer() const
Definition: Address.h:38
iterator begin() const
Returns an iterator pointing to the innermost EH scope.
Definition: CGCleanup.h:567
llvm::BasicBlock * EmitLandingPad()
Emits a landing pad for the current EH stack.
A protected scope for zero-cost EH handling.
Definition: CGCleanup.h:44
Defines the Objective-C statement AST node classes.
A C++ throw-expression (C++ [except.throw]).
Definition: ExprCXX.h:928
static bool useLibGCCSEHPersonality(const llvm::Triple &T)
On Win64, use libgcc&#39;s SEH personality function.
A scope which attempts to handle some, possibly all, types of exceptions.
Definition: CGCleanup.h:148
The collection of all-type qualifiers we support.
Definition: Type.h:116
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:37
const char * CatchallRethrowFn
Definition: CGCleanup.h:610
CodeGenFunction - This class organizes the per-function state that is used while generating LLVM code...
Holds long-lived AST nodes (such as types and decls) that can be referred to throughout the semantic ...
Definition: ASTContext.h:128
QualType getCaughtType() const
Definition: StmtCXX.cpp:20
SmallVector< Address, 1 > SEHCodeSlotStack
A stack of exception code slots.
static const EHPersonality GNU_CPlusPlus_SJLJ
Definition: CGCleanup.h:625
const FunctionDecl * CurSEHParent
llvm::CallInst * EmitRuntimeCall(llvm::Value *callee, const Twine &name="")
Denotes a cleanup that should run when a scope is exited using exceptional control flow (a throw stat...
Definition: EHScopeStack.h:81
static const EHPersonality & get(CodeGenModule &CGM, const FunctionDecl *FD)
Keeps track of the various options that can be enabled, which controls the dialect of C or C++ that i...
Definition: LangOptions.h:48
Address getExceptionSlot()
Returns a pointer to the function&#39;s exception object and selector slot, which is assigned in every la...
void setFilter(unsigned i, llvm::Value *filterValue)
Definition: CGCleanup.h:463
class EHCatchScope * pushCatch(unsigned NumHandlers)
Push a set of catch handlers on the stack.
Definition: CGCleanup.cpp:251
bool isNeXTFamily() const
Is this runtime basically of the NeXT family of runtimes?
Definition: ObjCRuntime.h:133
static llvm::Constant * getFreeExceptionFn(CodeGenModule &CGM)
Definition: CGException.cpp:33
static llvm::Constant * getCatchAllValue(CodeGenFunction &CGF)
Returns the value to inject into a selector to indicate the presence of a catch-all.
void ExitSEHTryStmt(const SEHTryStmt &S)
QualType getExceptionType(unsigned i) const
Definition: Type.h:3457
iterator begin() const
Definition: CGCleanup.h:224
CharUnits getAlignment() const
Return the alignment of this pointer.
Definition: Address.h:67
child_range children()
Definition: Stmt.cpp:208
const Handler & getHandler(unsigned I) const
Definition: CGCleanup.h:209
static const EHPersonality GNUstep_ObjC
Definition: CGCleanup.h:621
llvm::Constant * getTerminateFn()
Get the declaration of std::terminate for the platform.
Definition: CGException.cpp:51
llvm::BasicBlock * getInvokeDestImpl()
llvm::Function * GenerateSEHFinallyFunction(CodeGenFunction &ParentCGF, const SEHFinallyStmt &Finally)
llvm::BasicBlock * createBasicBlock(const Twine &name="", llvm::Function *parent=nullptr, llvm::BasicBlock *before=nullptr)
createBasicBlock - Create an LLVM basic block.
Denotes a cleanup that should run when a scope is exited using normal control flow (falling off the e...
Definition: EHScopeStack.h:85
void ForceCleanup(std::initializer_list< llvm::Value **> ValuesToReload={})
Force the emission of cleanups now, instead of waiting until this object is destroyed.
This represents the body of a CapturedStmt, and serves as its DeclContext.
Definition: Decl.h:3756
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:91
CanQualType UnsignedCharTy
Definition: ASTContext.h:974
Represents the this expression in C++.
Definition: ExprCXX.h:888
llvm::Constant * CreateRuntimeFunction(llvm::FunctionType *Ty, StringRef Name, llvm::AttributeList ExtraAttrs=llvm::AttributeList(), bool Local=false)
Create a new runtime function with the specified type and name.
static ImplicitParamDecl * Create(ASTContext &C, DeclContext *DC, SourceLocation IdLoc, IdentifierInfo *Id, QualType T, ImplicitParamKind ParamKind)
Create implicit parameter.
Definition: Decl.cpp:4155
&#39;watchos&#39; is a variant of iOS for Apple&#39;s watchOS.
Definition: ObjCRuntime.h:46
bool isValid() const
Definition: Address.h:36
Represents a prototype with parameter type info, e.g.
Definition: Type.h:3170
llvm::CallInst * EmitNounwindRuntimeCall(llvm::Value *callee, const Twine &name="")
static const EHPersonality MSVC_except_handler
Definition: CGCleanup.h:627
static llvm::Constant * getOpaquePersonalityFn(CodeGenModule &CGM, const EHPersonality &Personality)
SourceLocation getLocEnd() const LLVM_READONLY
Definition: Stmt.cpp:270
CatchTypeInfo Type
A type info value, or null (C++ null, not an LLVM null pointer) for a catch-all.
Definition: CGCleanup.h:158
void EmitCapturedLocals(CodeGenFunction &ParentCGF, const Stmt *OutlinedStmt, bool IsFilter)
Scan the outlined statement for captures from the parent function.
Expr - This represents one expression.
Definition: Expr.h:106
void enter(CodeGenFunction &CGF, const Stmt *Finally, llvm::Constant *beginCatchFn, llvm::Constant *endCatchFn, llvm::Constant *rethrowFn)
Enters a finally block for an implementation using zero-cost exceptions.
static bool PersonalityHasOnlyCXXUses(llvm::Constant *Fn)
Check whether a personality function could reasonably be swapped for a C++ personality function...
&#39;macosx&#39; is the Apple-provided NeXT-derived runtime on Mac OS X platforms that use the non-fragile AB...
Definition: ObjCRuntime.h:32
static Address invalid()
Definition: Address.h:35
Enters a new scope for capturing cleanups, all of which will be executed once the scope is exited...
const FunctionProtoType * T
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:125
VarDecl * getExceptionDecl() const
Definition: StmtCXX.h:50
llvm::PointerType * getType() const
Return the type of the pointer value.
Definition: Address.h:44
void EmitSEHTryStmt(const SEHTryStmt &S)
llvm::BasicBlock * Block
The catch handler for this type.
Definition: CGCleanup.h:161
static CharUnits fromQuantity(QuantityType Quantity)
fromQuantity - Construct a CharUnits quantity from a raw integer type.
Definition: CharUnits.h:63
CXXTryStmt - A C++ try block, including all handlers.
Definition: StmtCXX.h:65
void add(RValue rvalue, QualType type, bool needscopy=false)
Definition: CGCall.h:207
bool refersToEnclosingVariableOrCapture() const
Does this DeclRefExpr refer to an enclosing local or a captured variable?
Definition: Expr.h:1165
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:627
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:1765
QualType getType() const
Definition: Expr.h:128
static const EHPersonality & getObjCXXPersonality(const llvm::Triple &T, const LangOptions &L)
Determines the personality function to use when both C++ and Objective-C exceptions are being caught...
static const EHPersonality GNU_ObjCXX
Definition: CGCleanup.h:622
bool hasTerminate() const
Does this runtime provide an objc_terminate function?
Definition: ObjCRuntime.h:257
clang::ObjCRuntime ObjCRuntime
Definition: LangOptions.h:116
static const EHPersonality GNU_ObjC_SEH
Definition: CGCleanup.h:620
const TargetInfo & getTarget() const
ValueDecl * getDecl()
Definition: Expr.h:1041
&#39;gnustep&#39; is the modern non-fragile GNUstep runtime.
Definition: ObjCRuntime.h:53
const LangOptions & getLangOpts() const
ASTContext & getContext() const
llvm::StoreInst * CreateFlagStore(bool Value, llvm::Value *Addr)
Emit a store to an i1 flag variable.
Definition: CGBuilder.h:136
GlobalDecl - represents a global declaration.
Definition: GlobalDecl.h:29
unsigned getBuiltinCallee() const
getBuiltinCallee - If this is a call to a builtin, return the builtin ID of the callee.
Definition: Expr.cpp:1279
llvm::BasicBlock * getEHDispatchBlock(EHScopeStack::stable_iterator scope)
The l-value was considered opaque, so the alignment was determined from a type.
static void emitFilterDispatchBlock(CodeGenFunction &CGF, EHFilterScope &filterScope)
Emit the dispatch block for a filter scope if necessary.
Address recoverAddrOfEscapedLocal(CodeGenFunction &ParentCGF, Address ParentVar, llvm::Value *ParentFP)
Recovers the address of a local in a parent function.
Enumerates target-specific builtins in their own namespaces within namespace clang.
Address CreateBitCast(Address Addr, llvm::Type *Ty, const llvm::Twine &Name="")
Definition: CGBuilder.h:142
static const EHPersonality & getObjCPersonality(const llvm::Triple &T, const LangOptions &L)
Encodes a location in the source.
void EnsureInsertPoint()
EnsureInsertPoint - Ensure that an insertion point is defined so that emitted IR has a place to go...
A saved depth on the scope stack.
Definition: EHScopeStack.h:107
unsigned getNumHandlers() const
Definition: StmtCXX.h:103
bool isVariablyModifiedType() const
Whether this type is a variably-modified type (C99 6.7.5).
Definition: Type.h:1811
&#39;objfw&#39; is the Objective-C runtime included in ObjFW
Definition: ObjCRuntime.h:56
llvm::BasicBlock * getUnreachableBlock()
llvm::CallSite EmitRuntimeCallOrInvoke(llvm::Value *callee, ArrayRef< llvm::Value *> args, const Twine &name="")
Emits a call or invoke instruction to the given runtime function.
Definition: CGCall.cpp:3657
Kind getKind() const
Definition: ObjCRuntime.h:75
MangleContext - Context for tracking state which persists across multiple calls to the C++ name mangl...
Definition: Mangle.h:42
void EmitStmt(const Stmt *S, ArrayRef< const Attr *> Attrs=None)
EmitStmt - Emit the code for the statement.
Definition: CGStmt.cpp:48
The noexcept specifier evaluates to true.
Definition: Type.h:3452
CanQualType VoidTy
Definition: ASTContext.h:965
bool isObjCObjectPointerType() const
Definition: Type.h:5841
An aligned address.
Definition: Address.h:25
llvm::BasicBlock * getEHResumeBlock(bool isCleanup)
void setCachedEHDispatchBlock(llvm::BasicBlock *block)
Definition: CGCleanup.h:128
llvm::Instruction * CurrentFuncletPad
llvm::Value * getFilter(unsigned i) const
Definition: CGCleanup.h:468
JumpDest getJumpDestInCurrentScope(llvm::BasicBlock *Target)
The given basic block lies in the current EH scope, but may be a target of a potentially scope-crossi...
const VersionTuple & getVersion() const
Definition: ObjCRuntime.h:76
void EmitStartEHSpec(const Decl *D)
EmitStartEHSpec - Emit the start of the exception spec.
The MS C++ ABI needs a pointer to RTTI data plus some flags to describe the type of a catch handler...
Definition: CGCleanup.h:38
static const EHPersonality & getCXXPersonality(const llvm::Triple &T, const LangOptions &L)
ExceptionSpecificationType getExceptionSpecType() const
Get the kind of exception specification on this function.
Definition: Type.h:3426
SourceLocation getExprLoc() const LLVM_READONLY
getExprLoc - Return the preferred location for the arrow when diagnosing a problem with a generic exp...
Definition: Expr.cpp:216
static const EHPersonality NeXT_ObjC
Definition: CGCleanup.h:623
FunctionArgList - Type for representing both the decl and type of parameters to a function...
Definition: CGCall.h:276
llvm::BasicBlock * getMSVCDispatchBlock(EHScopeStack::stable_iterator scope)
CGFunctionInfo - Class to encapsulate the information about a function definition.
Kind getKind() const
Definition: CGCleanup.h:114
This class organizes the cross-function state that is used while generating LLVM code.
Dataflow Directional Tag Classes.
static ApplyDebugLocation CreateDefaultArtificial(CodeGenFunction &CGF, SourceLocation TemporaryLocation)
Apply TemporaryLocation if it is valid.
Definition: CGDebugInfo.h:658
static bool LandingPadHasOnlyCXXUses(llvm::LandingPadInst *LPI)
Check whether a landingpad instruction only uses C++ features.
static const EHPersonality GNU_CPlusPlus_SEH
Definition: CGCleanup.h:626
The basic abstraction for the target Objective-C runtime.
Definition: ObjCRuntime.h:25
static const EHPersonality GNU_ObjC
Definition: CGCleanup.h:618
static bool isNonEHScope(const EHScope &S)
Check whether this is a non-EH scope, i.e.
void EmitAnyExprToExn(const Expr *E, Address Addr)
llvm::LoadInst * CreateAlignedLoad(llvm::Value *Addr, CharUnits Align, const llvm::Twine &Name="")
Definition: CGBuilder.h:91
llvm::LoadInst * CreateLoad(Address Addr, const llvm::Twine &Name="")
Definition: CGBuilder.h:70
SEHExceptStmt * getExceptHandler() const
Returns 0 if not defined.
Definition: Stmt.cpp:930
llvm::Function * getIntrinsic(unsigned IID, ArrayRef< llvm::Type *> Tys=None)
llvm::StoreInst * CreateStore(llvm::Value *Val, Address Addr, bool IsVolatile=false)
Definition: CGBuilder.h:108
llvm::Module & getModule() const
Represents a __leave statement.
Definition: Stmt.h:1998
&#39;ios&#39; is the Apple-provided NeXT-derived runtime on iOS or the iOS simulator; it is always non-fragil...
Definition: ObjCRuntime.h:42
static const EHPersonality GNU_CPlusPlus
Definition: CGCleanup.h:624
llvm::LoadInst * CreateFlagLoad(llvm::Value *Addr, const llvm::Twine &Name="")
Emit a load from an i1 flag variable.
Definition: CGBuilder.h:129
llvm::StringRef getName() const
Return the IR name of the pointer value.
Definition: Address.h:62
static const EHPersonality GNU_ObjC_SJLJ
Definition: CGCleanup.h:619
Internal linkage, which indicates that the entity can be referred to from within the translation unit...
Definition: Linkage.h:33
ExceptionSpecificationType
The various types of exception specifications that exist in C++11.
void EmitBlock(llvm::BasicBlock *BB, bool IsFinished=false)
EmitBlock - Emit the given block.
Definition: CGStmt.cpp:436
void EnterCXXTryStmt(const CXXTryStmt &S, bool IsFnTryBlock=false)
SEHFinallyStmt * getFinallyHandler() const
Definition: Stmt.cpp:934
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:5623
Expr * getFilterExpr() const
Definition: Stmt.h:1896
llvm::BasicBlock * getTerminateLandingPad()
getTerminateLandingPad - Return a landing pad that just calls terminate.
CXXCatchStmt - This represents a C++ catch block.
Definition: StmtCXX.h:29
llvm::Type * ConvertType(QualType T)
Qualifiers getQualifiers() const
Retrieve the set of qualifiers applied to this type.
Definition: Type.h:5570
static const EHPersonality GNU_C_SEH
Definition: CGCleanup.h:617
static const EHPersonality & getCPersonality(const llvm::Triple &T, const LangOptions &L)
The exceptions personality for a function.
Definition: CGCleanup.h:604
llvm::Constant * RTTI
Definition: CGCleanup.h:39
CompoundStmt * getTryBlock()
Definition: StmtCXX.h:96
llvm::Value * EmitSEHAbnormalTermination()
CallExpr - Represents a function call (C99 6.5.2.2, C++ [expr.call]).
Definition: Expr.h:2209
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:973
An exceptions scope which filters exceptions thrown through it.
Definition: CGCleanup.h:438
A reference to a declared variable, function, enum, etc.
Definition: Expr.h:956
static RValue get(llvm::Value *V)
Definition: CGValue.h:86
void ExitCXXTryStmt(const CXXTryStmt &S, bool IsFnTryBlock=false)
void EmitBranchThroughCleanup(JumpDest Dest)
EmitBranchThroughCleanup - Emit a branch from the current insert block through the normal cleanup han...
Definition: CGCleanup.cpp:1034
void EmitEndEHSpec(const Decl *D)
EmitEndEHSpec - Emit the end of the exception spec.
static llvm::Constant * getCatchallRethrowFn(CodeGenModule &CGM, StringRef Name)
Definition: CGException.cpp:77
llvm::StoreInst * CreateAlignedStore(llvm::Value *Val, llvm::Value *Addr, CharUnits Align, bool IsVolatile=false)
Definition: CGBuilder.h:115
QualType getType() const
Definition: Decl.h:602
NoexceptResult getNoexceptSpec(const ASTContext &Ctx) const
Get the meaning of the noexcept spec on this function, if any.
Definition: Type.cpp:2802
Information for lazily generating a cleanup.
Definition: EHScopeStack.h:147
A non-stable pointer into the scope stack.
Definition: CGCleanup.h:503
void EmitBlockAfterUses(llvm::BasicBlock *BB)
EmitBlockAfterUses - Emit the given block somewhere hopefully near its uses, and leave the insertion ...
Definition: CGStmt.cpp:473
static void emitCatchPadBlock(CodeGenFunction &CGF, EHCatchScope &CatchScope)
SourceLocation getLocStart() const LLVM_READONLY
Definition: Stmt.cpp:257
CallArgList - Type for representing both the value and type of arguments in a call.
Definition: CGCall.h:182
void PopCleanupBlock(bool FallThroughIsBranchThrough=false)
PopCleanupBlock - Will pop the cleanup entry on the stack and process all branch fixups.
Definition: CGCleanup.cpp:640
void setHandler(unsigned I, llvm::Constant *Type, llvm::BasicBlock *Block)
Definition: CGCleanup.h:197
CompoundStmt * getTryBlock() const
Definition: Stmt.h:1977
CompoundStmt * getBlock() const
Definition: Stmt.h:1900
void EmitCXXThrowExpr(const CXXThrowExpr *E, bool KeepInsertionPoint=true)
bool isLocalVarDeclOrParm() const
Similar to isLocalVarDecl but also includes parameters.
Definition: Decl.h:1056
RValue EmitCall(const CGFunctionInfo &CallInfo, const CGCallee &Callee, ReturnValueSlot ReturnValue, const CallArgList &Args, llvm::Instruction **callOrInvoke=nullptr)
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:3708
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.
const llvm::Triple & getTriple() const