CGException.cpp revision 8755ec336108839b9621c3b18f0e175f8a3b671c 
1//===--- CGException.cpp - Emit LLVM Code for C++ exceptions --------------===//
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 "clang/AST/StmtCXX.h"
15
16#include "llvm/Intrinsics.h"
17
18#include "CodeGenFunction.h"
19using namespace clang;
20using namespace CodeGen;
21
22static llvm::Constant *getAllocateExceptionFn(CodeGenFunction &CGF) {
23  // void *__cxa_allocate_exception(size_t thrown_size);
24  const llvm::Type *SizeTy = CGF.ConvertType(CGF.getContext().getSizeType());
25  std::vector<const llvm::Type*> Args(1, SizeTy);
26
27  const llvm::FunctionType *FTy =
28  llvm::FunctionType::get(llvm::Type::getInt8PtrTy(CGF.getLLVMContext()),
29                          Args, false);
30
31  return CGF.CGM.CreateRuntimeFunction(FTy, "__cxa_allocate_exception");
32}
33
34static llvm::Constant *getFreeExceptionFn(CodeGenFunction &CGF) {
35  // void __cxa_free_exception(void *thrown_exception);
36  const llvm::Type *Int8PtrTy = llvm::Type::getInt8PtrTy(CGF.getLLVMContext());
37  std::vector<const llvm::Type*> Args(1, Int8PtrTy);
38
39  const llvm::FunctionType *FTy =
40  llvm::FunctionType::get(llvm::Type::getVoidTy(CGF.getLLVMContext()),
41                          Args, false);
42
43  return CGF.CGM.CreateRuntimeFunction(FTy, "__cxa_free_exception");
44}
45
46static llvm::Constant *getThrowFn(CodeGenFunction &CGF) {
47  // void __cxa_throw(void *thrown_exception, std::type_info *tinfo,
48  //                  void (*dest) (void *));
49
50  const llvm::Type *Int8PtrTy = llvm::Type::getInt8PtrTy(CGF.getLLVMContext());
51  std::vector<const llvm::Type*> Args(3, Int8PtrTy);
52
53  const llvm::FunctionType *FTy =
54    llvm::FunctionType::get(llvm::Type::getVoidTy(CGF.getLLVMContext()),
55                            Args, false);
56
57  return CGF.CGM.CreateRuntimeFunction(FTy, "__cxa_throw");
58}
59
60static llvm::Constant *getReThrowFn(CodeGenFunction &CGF) {
61  // void __cxa_rethrow();
62
63  const llvm::FunctionType *FTy =
64    llvm::FunctionType::get(llvm::Type::getVoidTy(CGF.getLLVMContext()), false);
65
66  return CGF.CGM.CreateRuntimeFunction(FTy, "__cxa_rethrow");
67}
68
69static llvm::Constant *getBeginCatchFn(CodeGenFunction &CGF) {
70  // void* __cxa_begin_catch();
71
72  const llvm::Type *Int8PtrTy = llvm::Type::getInt8PtrTy(CGF.getLLVMContext());
73  std::vector<const llvm::Type*> Args(1, Int8PtrTy);
74
75  const llvm::FunctionType *FTy =
76    llvm::FunctionType::get(Int8PtrTy, Args, false);
77
78  return CGF.CGM.CreateRuntimeFunction(FTy, "__cxa_begin_catch");
79}
80
81static llvm::Constant *getEndCatchFn(CodeGenFunction &CGF) {
82  // void __cxa_end_catch();
83
84  const llvm::FunctionType *FTy =
85    llvm::FunctionType::get(llvm::Type::getVoidTy(CGF.getLLVMContext()), false);
86
87  return CGF.CGM.CreateRuntimeFunction(FTy, "__cxa_end_catch");
88}
89
90static llvm::Constant *getUnexpectedFn(CodeGenFunction &CGF) {
91  // void __cxa_call_unexepcted(void *thrown_exception);
92
93  const llvm::Type *Int8PtrTy = llvm::Type::getInt8PtrTy(CGF.getLLVMContext());
94  std::vector<const llvm::Type*> Args(1, Int8PtrTy);
95
96  const llvm::FunctionType *FTy =
97    llvm::FunctionType::get(llvm::Type::getVoidTy(CGF.getLLVMContext()),
98                            Args, false);
99
100  return CGF.CGM.CreateRuntimeFunction(FTy, "__cxa_call_unexpected");
101}
102
103// FIXME: Eventually this will all go into the backend.  Set from the target for
104// now.
105static int using_sjlj_exceptions = 0;
106
107static llvm::Constant *getUnwindResumeOrRethrowFn(CodeGenFunction &CGF) {
108  const llvm::Type *Int8PtrTy = llvm::Type::getInt8PtrTy(CGF.getLLVMContext());
109  std::vector<const llvm::Type*> Args(1, Int8PtrTy);
110
111  const llvm::FunctionType *FTy =
112    llvm::FunctionType::get(llvm::Type::getVoidTy(CGF.getLLVMContext()), Args,
113                            false);
114
115  if (using_sjlj_exceptions)
116    return CGF.CGM.CreateRuntimeFunction(FTy, "_Unwind_SjLj_Resume");
117  return CGF.CGM.CreateRuntimeFunction(FTy, "_Unwind_Resume_or_Rethrow");
118}
119
120static llvm::Constant *getTerminateFn(CodeGenFunction &CGF) {
121  // void __terminate();
122
123  const llvm::FunctionType *FTy =
124    llvm::FunctionType::get(llvm::Type::getVoidTy(CGF.getLLVMContext()), false);
125
126  return CGF.CGM.CreateRuntimeFunction(FTy, "_ZSt9terminatev");
127}
128
129// CopyObject - Utility to copy an object.  Calls copy constructor as necessary.
130// N is casted to the right type.
131static void CopyObject(CodeGenFunction &CGF, const Expr *E, llvm::Value *N) {
132  QualType ObjectType = E->getType();
133
134  // Store the throw exception in the exception object.
135  if (!CGF.hasAggregateLLVMType(ObjectType)) {
136    llvm::Value *Value = CGF.EmitScalarExpr(E);
137    const llvm::Type *ValuePtrTy = Value->getType()->getPointerTo(0);
138
139    CGF.Builder.CreateStore(Value, CGF.Builder.CreateBitCast(N, ValuePtrTy));
140  } else {
141    const llvm::Type *Ty = CGF.ConvertType(ObjectType)->getPointerTo(0);
142    const CXXRecordDecl *RD;
143    RD = cast<CXXRecordDecl>(ObjectType->getAs<RecordType>()->getDecl());
144    llvm::Value *This = CGF.Builder.CreateBitCast(N, Ty);
145    if (RD->hasTrivialCopyConstructor()) {
146      CGF.EmitAggExpr(E, This, false);
147    } else if (CXXConstructorDecl *CopyCtor
148               = RD->getCopyConstructor(CGF.getContext(), 0)) {
149      // All temporaries end before we call __cxa_throw
150      // FIXME: Doesn't work well with eh31.C and PopCXXTemporary
151      // CodeGenFunction::CleanupScope TryScope(CGF);
152      {
153        // These actions are only on the exceptional edge.
154        if (0) {
155        // FIXME: Doesn't work well with eh31.C and PopCXXTemporary
156        CodeGenFunction::DelayedCleanupBlock Scope(CGF, true);
157
158        llvm::Constant *FreeExceptionFn = getFreeExceptionFn(CGF);
159        const llvm::Type *Int8PtrTy
160          = llvm::Type::getInt8PtrTy(CGF.getLLVMContext());
161        llvm::Value *ExceptionPtr = CGF.Builder.CreateBitCast(N, Int8PtrTy);
162        CGF.Builder.CreateCall(FreeExceptionFn, ExceptionPtr);
163        }
164      }
165
166      llvm::Value *Src = CGF.EmitLValue(E).getAddress();
167
168      llvm::BasicBlock *TerminateHandler = CGF.getTerminateHandler();
169      llvm::BasicBlock *PrevLandingPad = CGF.getInvokeDest();
170      CGF.setInvokeDest(TerminateHandler);
171
172      // Stolen from EmitClassAggrMemberwiseCopy
173      llvm::Value *Callee = CGF.CGM.GetAddrOfCXXConstructor(CopyCtor,
174                                                            Ctor_Complete);
175      CallArgList CallArgs;
176      CallArgs.push_back(std::make_pair(RValue::get(This),
177                                      CopyCtor->getThisType(CGF.getContext())));
178
179      // Push the Src ptr.
180      CallArgs.push_back(std::make_pair(RValue::get(Src),
181                                        CopyCtor->getParamDecl(0)->getType()));
182      QualType ResultType =
183        CopyCtor->getType()->getAs<FunctionType>()->getResultType();
184      CGF.EmitCall(CGF.CGM.getTypes().getFunctionInfo(ResultType, CallArgs),
185                   Callee, CallArgs, CopyCtor);
186      CGF.setInvokeDest(PrevLandingPad);
187    } else
188      llvm::llvm_unreachable("uncopyable object");
189  }
190}
191
192// CopyObject - Utility to copy an object.  Calls copy constructor as necessary.
193// N is casted to the right type.
194static void CopyObject(CodeGenFunction &CGF, QualType ObjectType,
195                       bool WasPointer, llvm::Value *E, llvm::Value *N) {
196  // Store the throw exception in the exception object.
197  if (WasPointer || !CGF.hasAggregateLLVMType(ObjectType)) {
198    llvm::Value *Value = E;
199    if (!WasPointer)
200      Value = CGF.Builder.CreateLoad(Value);
201    const llvm::Type *ValuePtrTy = Value->getType()->getPointerTo(0);
202    CGF.Builder.CreateStore(Value, CGF.Builder.CreateBitCast(N, ValuePtrTy));
203  } else {
204    const llvm::Type *Ty = CGF.ConvertType(ObjectType)->getPointerTo(0);
205    const CXXRecordDecl *RD;
206    RD = cast<CXXRecordDecl>(ObjectType->getAs<RecordType>()->getDecl());
207    llvm::Value *This = CGF.Builder.CreateBitCast(N, Ty);
208    if (RD->hasTrivialCopyConstructor()) {
209      CGF.EmitAggregateCopy(This, E, ObjectType);
210    } else if (CXXConstructorDecl *CopyCtor
211               = RD->getCopyConstructor(CGF.getContext(), 0)) {
212      llvm::Value *Src = E;
213
214      // Stolen from EmitClassAggrMemberwiseCopy
215      llvm::Value *Callee = CGF.CGM.GetAddrOfCXXConstructor(CopyCtor,
216                                                            Ctor_Complete);
217      CallArgList CallArgs;
218      CallArgs.push_back(std::make_pair(RValue::get(This),
219                                      CopyCtor->getThisType(CGF.getContext())));
220
221      // Push the Src ptr.
222      CallArgs.push_back(std::make_pair(RValue::get(Src),
223                                        CopyCtor->getParamDecl(0)->getType()));
224      QualType ResultType =
225        CopyCtor->getType()->getAs<FunctionType>()->getResultType();
226      CGF.EmitCall(CGF.CGM.getTypes().getFunctionInfo(ResultType, CallArgs),
227                   Callee, CallArgs, CopyCtor);
228    } else
229      llvm::llvm_unreachable("uncopyable object");
230  }
231}
232
233void CodeGenFunction::EmitCXXThrowExpr(const CXXThrowExpr *E) {
234  if (!E->getSubExpr()) {
235    if (getInvokeDest()) {
236      llvm::BasicBlock *Cont = createBasicBlock("invoke.cont");
237      Builder.CreateInvoke(getReThrowFn(*this), Cont, getInvokeDest())
238        ->setDoesNotReturn();
239      EmitBlock(Cont);
240    } else
241      Builder.CreateCall(getReThrowFn(*this))->setDoesNotReturn();
242    Builder.CreateUnreachable();
243
244    // Clear the insertion point to indicate we are in unreachable code.
245    Builder.ClearInsertionPoint();
246    return;
247  }
248
249  QualType ThrowType = E->getSubExpr()->getType();
250
251  // Now allocate the exception object.
252  const llvm::Type *SizeTy = ConvertType(getContext().getSizeType());
253  uint64_t TypeSize = getContext().getTypeSize(ThrowType) / 8;
254
255  llvm::Constant *AllocExceptionFn = getAllocateExceptionFn(*this);
256  llvm::Value *ExceptionPtr =
257    Builder.CreateCall(AllocExceptionFn,
258                       llvm::ConstantInt::get(SizeTy, TypeSize),
259                       "exception");
260
261  CopyObject(*this, E->getSubExpr(), ExceptionPtr);
262
263  // Now throw the exception.
264  const llvm::Type *Int8PtrTy = llvm::Type::getInt8PtrTy(getLLVMContext());
265  llvm::Constant *TypeInfo = CGM.GenerateRTTI(ThrowType);
266  llvm::Constant *Dtor = llvm::Constant::getNullValue(Int8PtrTy);
267
268  if (getInvokeDest()) {
269    llvm::BasicBlock *Cont = createBasicBlock("invoke.cont");
270    llvm::InvokeInst *ThrowCall =
271      Builder.CreateInvoke3(getThrowFn(*this), Cont, getInvokeDest(),
272                            ExceptionPtr, TypeInfo, Dtor);
273    ThrowCall->setDoesNotReturn();
274    EmitBlock(Cont);
275  } else {
276    llvm::CallInst *ThrowCall =
277      Builder.CreateCall3(getThrowFn(*this), ExceptionPtr, TypeInfo, Dtor);
278    ThrowCall->setDoesNotReturn();
279  }
280  Builder.CreateUnreachable();
281
282  // Clear the insertion point to indicate we are in unreachable code.
283  Builder.ClearInsertionPoint();
284
285  // FIXME: For now, emit a dummy basic block because expr emitters in generally
286  // are not ready to handle emitting expressions at unreachable points.
287  EnsureInsertPoint();
288}
289
290void CodeGenFunction::EmitStartEHSpec(const Decl *D) {
291  const FunctionDecl* FD = dyn_cast_or_null<FunctionDecl>(D);
292  if (FD == 0)
293    return;
294  const FunctionProtoType *Proto = FD->getType()->getAs<FunctionProtoType>();
295  if (Proto == 0)
296    return;
297
298  assert(!Proto->hasAnyExceptionSpec() && "function with parameter pack");
299
300  if (!Proto->hasExceptionSpec())
301    return;
302
303  llvm::Constant *Personality =
304    CGM.CreateRuntimeFunction(llvm::FunctionType::get(llvm::Type::getInt32Ty
305                                                      (VMContext),
306                                                      true),
307                              "__gxx_personality_v0");
308  Personality = llvm::ConstantExpr::getBitCast(Personality, PtrToInt8Ty);
309  llvm::Value *llvm_eh_exception =
310    CGM.getIntrinsic(llvm::Intrinsic::eh_exception);
311  llvm::Value *llvm_eh_selector =
312    CGM.getIntrinsic(llvm::Intrinsic::eh_selector);
313  const llvm::IntegerType *Int8Ty;
314  const llvm::PointerType *PtrToInt8Ty;
315  Int8Ty = llvm::Type::getInt8Ty(VMContext);
316  // C string type.  Used in lots of places.
317  PtrToInt8Ty = llvm::PointerType::getUnqual(Int8Ty);
318  llvm::Constant *Null = llvm::ConstantPointerNull::get(PtrToInt8Ty);
319  llvm::SmallVector<llvm::Value*, 8> SelectorArgs;
320
321  llvm::BasicBlock *PrevLandingPad = getInvokeDest();
322  llvm::BasicBlock *EHSpecHandler = createBasicBlock("ehspec.handler");
323  llvm::BasicBlock *Match = createBasicBlock("match");
324  llvm::BasicBlock *Unwind = 0;
325
326  assert(PrevLandingPad == 0 && "EHSpec has invoke context");
327
328  llvm::BasicBlock *Cont = createBasicBlock("cont");
329
330  EmitBranchThroughCleanup(Cont);
331
332  // Emit the statements in the try {} block
333  setInvokeDest(EHSpecHandler);
334
335  EmitBlock(EHSpecHandler);
336  // Exception object
337  llvm::Value *Exc = Builder.CreateCall(llvm_eh_exception, "exc");
338  llvm::Value *RethrowPtr = CreateTempAlloca(Exc->getType(), "_rethrow");
339
340  SelectorArgs.push_back(Exc);
341  SelectorArgs.push_back(Personality);
342  SelectorArgs.push_back(llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext),
343                                                Proto->getNumExceptions()+1));
344
345  for (unsigned i = 0; i < Proto->getNumExceptions(); ++i) {
346    QualType Ty = Proto->getExceptionType(i);
347    llvm::Value *EHType
348      = CGM.GenerateRTTI(Ty.getNonReferenceType());
349    SelectorArgs.push_back(EHType);
350  }
351  if (Proto->getNumExceptions())
352    SelectorArgs.push_back(Null);
353
354  // Find which handler was matched.
355  llvm::Value *Selector
356    = Builder.CreateCall(llvm_eh_selector, SelectorArgs.begin(),
357                         SelectorArgs.end(), "selector");
358  if (Proto->getNumExceptions()) {
359    Unwind = createBasicBlock("Unwind");
360
361    Builder.CreateStore(Exc, RethrowPtr);
362    Builder.CreateCondBr(Builder.CreateICmpSLT(Selector,
363                                               llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext),
364                                                                      0)),
365                         Match, Unwind);
366
367    EmitBlock(Match);
368  }
369  Builder.CreateCall(getUnexpectedFn(*this), Exc)->setDoesNotReturn();
370  Builder.CreateUnreachable();
371
372  if (Proto->getNumExceptions()) {
373    EmitBlock(Unwind);
374    Builder.CreateCall(getUnwindResumeOrRethrowFn(*this),
375                       Builder.CreateLoad(RethrowPtr));
376    Builder.CreateUnreachable();
377  }
378
379  EmitBlock(Cont);
380}
381
382void CodeGenFunction::EmitEndEHSpec(const Decl *D) {
383  const FunctionDecl* FD = dyn_cast_or_null<FunctionDecl>(D);
384  if (FD == 0)
385    return;
386  const FunctionProtoType *Proto = FD->getType()->getAs<FunctionProtoType>();
387  if (Proto == 0)
388    return;
389
390  if (!Proto->hasExceptionSpec())
391    return;
392
393  setInvokeDest(0);
394}
395
396void CodeGenFunction::EmitCXXTryStmt(const CXXTryStmt &S) {
397  // Pointer to the personality function
398  llvm::Constant *Personality =
399    CGM.CreateRuntimeFunction(llvm::FunctionType::get(llvm::Type::getInt32Ty
400                                                      (VMContext),
401                                                      true),
402                              "__gxx_personality_v0");
403  Personality = llvm::ConstantExpr::getBitCast(Personality, PtrToInt8Ty);
404  llvm::Value *llvm_eh_exception =
405    CGM.getIntrinsic(llvm::Intrinsic::eh_exception);
406  llvm::Value *llvm_eh_selector =
407    CGM.getIntrinsic(llvm::Intrinsic::eh_selector);
408
409  llvm::BasicBlock *PrevLandingPad = getInvokeDest();
410  llvm::BasicBlock *TryHandler = createBasicBlock("try.handler");
411  llvm::BasicBlock *FinallyBlock = createBasicBlock("finally");
412  llvm::BasicBlock *FinallyRethrow = createBasicBlock("finally.throw");
413  llvm::BasicBlock *FinallyEnd = createBasicBlock("finally.end");
414
415  // Push an EH context entry, used for handling rethrows.
416  PushCleanupBlock(FinallyBlock);
417
418  // Emit the statements in the try {} block
419  setInvokeDest(TryHandler);
420
421  // FIXME: We should not have to do this here.  The AST should have the member
422  // initializers under the CXXTryStmt's TryBlock.
423  if (OuterTryBlock == &S) {
424    GlobalDecl GD = CurGD;
425    const FunctionDecl *FD = cast<FunctionDecl>(GD.getDecl());
426
427    if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(FD)) {
428      size_t OldCleanupStackSize = CleanupEntries.size();
429      EmitCtorPrologue(CD, CurGD.getCtorType());
430      EmitStmt(S.getTryBlock());
431
432      // If any of the member initializers are temporaries bound to references
433      // make sure to emit their destructors.
434      EmitCleanupBlocks(OldCleanupStackSize);
435    } else if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(FD)) {
436      llvm::BasicBlock *DtorEpilogue  = createBasicBlock("dtor.epilogue");
437      PushCleanupBlock(DtorEpilogue);
438
439      EmitStmt(S.getTryBlock());
440
441      CleanupBlockInfo Info = PopCleanupBlock();
442
443      assert(Info.CleanupBlock == DtorEpilogue && "Block mismatch!");
444      EmitBlock(DtorEpilogue);
445      EmitDtorEpilogue(DD, GD.getDtorType());
446
447      if (Info.SwitchBlock)
448        EmitBlock(Info.SwitchBlock);
449      if (Info.EndBlock)
450        EmitBlock(Info.EndBlock);
451    } else
452      EmitStmt(S.getTryBlock());
453  } else
454    EmitStmt(S.getTryBlock());
455
456  // Jump to end if there is no exception
457  EmitBranchThroughCleanup(FinallyEnd);
458
459  llvm::BasicBlock *TerminateHandler = getTerminateHandler();
460
461  // Emit the handlers
462  EmitBlock(TryHandler);
463
464  const llvm::IntegerType *Int8Ty;
465  const llvm::PointerType *PtrToInt8Ty;
466  Int8Ty = llvm::Type::getInt8Ty(VMContext);
467  // C string type.  Used in lots of places.
468  PtrToInt8Ty = llvm::PointerType::getUnqual(Int8Ty);
469  llvm::Constant *Null = llvm::ConstantPointerNull::get(PtrToInt8Ty);
470  llvm::SmallVector<llvm::Value*, 8> SelectorArgs;
471  llvm::Value *llvm_eh_typeid_for =
472    CGM.getIntrinsic(llvm::Intrinsic::eh_typeid_for);
473  // Exception object
474  llvm::Value *Exc = Builder.CreateCall(llvm_eh_exception, "exc");
475  llvm::Value *RethrowPtr = CreateTempAlloca(Exc->getType(), "_rethrow");
476
477  llvm::SmallVector<llvm::Value*, 8> Args;
478  Args.clear();
479  SelectorArgs.push_back(Exc);
480  SelectorArgs.push_back(Personality);
481
482  bool HasCatchAll = false;
483  for (unsigned i = 0; i<S.getNumHandlers(); ++i) {
484    const CXXCatchStmt *C = S.getHandler(i);
485    VarDecl *CatchParam = C->getExceptionDecl();
486    if (CatchParam) {
487      llvm::Value *EHType
488        = CGM.GenerateRTTI(C->getCaughtType().getNonReferenceType());
489      SelectorArgs.push_back(EHType);
490    } else {
491      // null indicates catch all
492      SelectorArgs.push_back(Null);
493      HasCatchAll = true;
494    }
495  }
496
497  // We use a cleanup unless there was already a catch all.
498  if (!HasCatchAll) {
499    SelectorArgs.push_back(Null);
500  }
501
502  // Find which handler was matched.
503  llvm::Value *Selector
504    = Builder.CreateCall(llvm_eh_selector, SelectorArgs.begin(),
505                         SelectorArgs.end(), "selector");
506  for (unsigned i = 0; i<S.getNumHandlers(); ++i) {
507    const CXXCatchStmt *C = S.getHandler(i);
508    VarDecl *CatchParam = C->getExceptionDecl();
509    Stmt *CatchBody = C->getHandlerBlock();
510
511    llvm::BasicBlock *Next = 0;
512
513    if (SelectorArgs[i+2] != Null) {
514      llvm::BasicBlock *Match = createBasicBlock("match");
515      Next = createBasicBlock("catch.next");
516      const llvm::Type *Int8PtrTy = llvm::Type::getInt8PtrTy(getLLVMContext());
517      llvm::Value *Id
518        = Builder.CreateCall(llvm_eh_typeid_for,
519                             Builder.CreateBitCast(SelectorArgs[i+2],
520                                                   Int8PtrTy));
521      Builder.CreateCondBr(Builder.CreateICmpEQ(Selector, Id),
522                           Match, Next);
523      EmitBlock(Match);
524    }
525
526    llvm::BasicBlock *MatchEnd = createBasicBlock("match.end");
527    llvm::BasicBlock *MatchHandler = createBasicBlock("match.handler");
528
529    PushCleanupBlock(MatchEnd);
530    setInvokeDest(MatchHandler);
531
532    llvm::Value *ExcObject = Builder.CreateCall(getBeginCatchFn(*this), Exc);
533
534    {
535      CleanupScope CatchScope(*this);
536      // Bind the catch parameter if it exists.
537      if (CatchParam) {
538        QualType CatchType = CatchParam->getType().getNonReferenceType();
539        setInvokeDest(TerminateHandler);
540        bool WasPointer = true;
541        if (!CatchType.getTypePtr()->isPointerType()) {
542          if (!isa<ReferenceType>(CatchParam->getType()))
543            WasPointer = false;
544          CatchType = getContext().getPointerType(CatchType);
545        }
546        ExcObject = Builder.CreateBitCast(ExcObject, ConvertType(CatchType));
547        EmitLocalBlockVarDecl(*CatchParam);
548        // FIXME: we need to do this sooner so that the EH region for the
549        // cleanup doesn't start until after the ctor completes, use a decl
550        // init?
551        CopyObject(*this, CatchParam->getType().getNonReferenceType(),
552                   WasPointer, ExcObject, GetAddrOfLocalVar(CatchParam));
553        setInvokeDest(MatchHandler);
554      }
555
556      EmitStmt(CatchBody);
557    }
558
559    EmitBranchThroughCleanup(FinallyEnd);
560
561    EmitBlock(MatchHandler);
562
563    llvm::Value *Exc = Builder.CreateCall(llvm_eh_exception, "exc");
564    // We are required to emit this call to satisfy LLVM, even
565    // though we don't use the result.
566    Args.clear();
567    Args.push_back(Exc);
568    Args.push_back(Personality);
569    Args.push_back(llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext),
570                                          0));
571    Builder.CreateCall(llvm_eh_selector, Args.begin(), Args.end());
572    Builder.CreateStore(Exc, RethrowPtr);
573    EmitBranchThroughCleanup(FinallyRethrow);
574
575    CodeGenFunction::CleanupBlockInfo Info = PopCleanupBlock();
576
577    EmitBlock(MatchEnd);
578
579    llvm::BasicBlock *Cont = createBasicBlock("invoke.cont");
580    Builder.CreateInvoke(getEndCatchFn(*this),
581                         Cont, TerminateHandler,
582                         Args.begin(), Args.begin());
583    EmitBlock(Cont);
584    if (Info.SwitchBlock)
585      EmitBlock(Info.SwitchBlock);
586    if (Info.EndBlock)
587      EmitBlock(Info.EndBlock);
588
589    Exc = Builder.CreateCall(llvm_eh_exception, "exc");
590    Builder.CreateStore(Exc, RethrowPtr);
591    EmitBranchThroughCleanup(FinallyRethrow);
592
593    if (Next)
594      EmitBlock(Next);
595  }
596  if (!HasCatchAll) {
597    Builder.CreateStore(Exc, RethrowPtr);
598    EmitBranchThroughCleanup(FinallyRethrow);
599  }
600
601  CodeGenFunction::CleanupBlockInfo Info = PopCleanupBlock();
602
603  setInvokeDest(PrevLandingPad);
604
605  EmitBlock(FinallyBlock);
606
607  if (Info.SwitchBlock)
608    EmitBlock(Info.SwitchBlock);
609  if (Info.EndBlock)
610    EmitBlock(Info.EndBlock);
611
612  // Branch around the rethrow code.
613  EmitBranch(FinallyEnd);
614
615  EmitBlock(FinallyRethrow);
616  // FIXME: Eventually we can chain the handlers together and just do a call
617  // here.
618  if (getInvokeDest()) {
619    llvm::BasicBlock *Cont = createBasicBlock("invoke.cont");
620    Builder.CreateInvoke(getUnwindResumeOrRethrowFn(*this), Cont,
621                         getInvokeDest(),
622                         Builder.CreateLoad(RethrowPtr));
623    EmitBlock(Cont);
624  } else
625    Builder.CreateCall(getUnwindResumeOrRethrowFn(*this),
626                       Builder.CreateLoad(RethrowPtr));
627
628  Builder.CreateUnreachable();
629
630  EmitBlock(FinallyEnd);
631}
632
633CodeGenFunction::EHCleanupBlock::~EHCleanupBlock() {
634  llvm::BasicBlock *Cont1 = CGF.createBasicBlock("cont");
635  CGF.EmitBranch(Cont1);
636  CGF.setInvokeDest(PreviousInvokeDest);
637
638
639  CGF.EmitBlock(CleanupHandler);
640
641  llvm::Constant *Personality =
642    CGF.CGM.CreateRuntimeFunction(llvm::FunctionType::get(llvm::Type::getInt32Ty
643                                                          (CGF.VMContext),
644                                                          true),
645                                  "__gxx_personality_v0");
646  Personality = llvm::ConstantExpr::getBitCast(Personality, CGF.PtrToInt8Ty);
647  llvm::Value *llvm_eh_exception =
648    CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_exception);
649  llvm::Value *llvm_eh_selector =
650    CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_selector);
651
652  llvm::Value *Exc = CGF.Builder.CreateCall(llvm_eh_exception, "exc");
653  const llvm::IntegerType *Int8Ty;
654  const llvm::PointerType *PtrToInt8Ty;
655  Int8Ty = llvm::Type::getInt8Ty(CGF.VMContext);
656  // C string type.  Used in lots of places.
657  PtrToInt8Ty = llvm::PointerType::getUnqual(Int8Ty);
658  llvm::Constant *Null = llvm::ConstantPointerNull::get(PtrToInt8Ty);
659  llvm::SmallVector<llvm::Value*, 8> Args;
660  Args.clear();
661  Args.push_back(Exc);
662  Args.push_back(Personality);
663  Args.push_back(Null);
664  CGF.Builder.CreateCall(llvm_eh_selector, Args.begin(), Args.end());
665
666  CGF.EmitBlock(CleanupEntryBB);
667
668  CGF.EmitBlock(Cont1);
669
670  if (CGF.getInvokeDest()) {
671    llvm::BasicBlock *Cont = CGF.createBasicBlock("invoke.cont");
672    CGF.Builder.CreateInvoke(getUnwindResumeOrRethrowFn(CGF), Cont,
673                             CGF.getInvokeDest(), Exc);
674    CGF.EmitBlock(Cont);
675  } else
676    CGF.Builder.CreateCall(getUnwindResumeOrRethrowFn(CGF), Exc);
677
678  CGF.Builder.CreateUnreachable();
679
680  CGF.EmitBlock(Cont);
681  if (CGF.Exceptions)
682    CGF.setInvokeDest(CleanupHandler);
683}
684
685llvm::BasicBlock *CodeGenFunction::getTerminateHandler() {
686  if (TerminateHandler)
687    return TerminateHandler;
688
689  llvm::BasicBlock *Cont = 0;
690
691  if (HaveInsertPoint()) {
692    Cont = createBasicBlock("cont");
693    EmitBranch(Cont);
694  }
695
696  llvm::Constant *Personality =
697    CGM.CreateRuntimeFunction(llvm::FunctionType::get(llvm::Type::getInt32Ty
698                                                      (VMContext),
699                                                      true),
700                              "__gxx_personality_v0");
701  Personality = llvm::ConstantExpr::getBitCast(Personality, PtrToInt8Ty);
702  llvm::Value *llvm_eh_exception =
703    CGM.getIntrinsic(llvm::Intrinsic::eh_exception);
704  llvm::Value *llvm_eh_selector =
705    CGM.getIntrinsic(llvm::Intrinsic::eh_selector);
706
707  // Set up terminate handler
708  TerminateHandler = createBasicBlock("terminate.handler");
709  EmitBlock(TerminateHandler);
710  llvm::Value *Exc = Builder.CreateCall(llvm_eh_exception, "exc");
711  // We are required to emit this call to satisfy LLVM, even
712  // though we don't use the result.
713  llvm::SmallVector<llvm::Value*, 8> Args;
714  Args.push_back(Exc);
715  Args.push_back(Personality);
716  Args.push_back(llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext),
717                                        1));
718  Builder.CreateCall(llvm_eh_selector, Args.begin(), Args.end());
719  llvm::CallInst *TerminateCall =
720    Builder.CreateCall(getTerminateFn(*this));
721  TerminateCall->setDoesNotReturn();
722  TerminateCall->setDoesNotThrow();
723  Builder.CreateUnreachable();
724
725  // Clear the insertion point to indicate we are in unreachable code.
726  Builder.ClearInsertionPoint();
727
728  if (Cont)
729    EmitBlock(Cont);
730
731  return TerminateHandler;
732}
733