CGException.cpp revision 04a67a6aa3dfdc92d57f7f8d93ba397348c868a4 
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// DestPtr is casted to the right type.
131static void CopyObject(CodeGenFunction &CGF, const Expr *E,
132                       llvm::Value *DestPtr, llvm::Value *ExceptionPtrPtr) {
133  QualType ObjectType = E->getType();
134
135  // Store the throw exception in the exception object.
136  if (!CGF.hasAggregateLLVMType(ObjectType)) {
137    llvm::Value *Value = CGF.EmitScalarExpr(E);
138    const llvm::Type *ValuePtrTy = Value->getType()->getPointerTo();
139
140    CGF.Builder.CreateStore(Value,
141                            CGF.Builder.CreateBitCast(DestPtr, ValuePtrTy));
142  } else {
143    const llvm::Type *Ty = CGF.ConvertType(ObjectType)->getPointerTo();
144    const CXXRecordDecl *RD =
145      cast<CXXRecordDecl>(ObjectType->getAs<RecordType>()->getDecl());
146
147    llvm::Value *This = CGF.Builder.CreateBitCast(DestPtr, Ty);
148    if (RD->hasTrivialCopyConstructor()) {
149      CGF.EmitAggExpr(E, This, false);
150    } else if (CXXConstructorDecl *CopyCtor
151               = RD->getCopyConstructor(CGF.getContext(), 0)) {
152      llvm::Value *CondPtr = 0;
153      if (CGF.Exceptions) {
154        CodeGenFunction::EHCleanupBlock Cleanup(CGF);
155        llvm::Constant *FreeExceptionFn = getFreeExceptionFn(CGF);
156
157        llvm::BasicBlock *CondBlock = CGF.createBasicBlock("cond.free");
158        llvm::BasicBlock *Cont = CGF.createBasicBlock("cont");
159        CondPtr = CGF.CreateTempAlloca(llvm::Type::getInt1Ty(CGF.getLLVMContext()),
160                                       "doEHfree");
161
162        CGF.Builder.CreateCondBr(CGF.Builder.CreateLoad(CondPtr),
163                                 CondBlock, Cont);
164        CGF.EmitBlock(CondBlock);
165
166        // Load the exception pointer.
167        llvm::Value *ExceptionPtr = CGF.Builder.CreateLoad(ExceptionPtrPtr);
168        CGF.Builder.CreateCall(FreeExceptionFn, ExceptionPtr);
169
170        CGF.EmitBlock(Cont);
171      }
172
173      if (CondPtr)
174        CGF.Builder.CreateStore(llvm::ConstantInt::getTrue(CGF.getLLVMContext()),
175                                CondPtr);
176
177      llvm::Value *Src = CGF.EmitLValue(E).getAddress();
178
179      if (CondPtr)
180        CGF.Builder.CreateStore(llvm::ConstantInt::getFalse(CGF.getLLVMContext()),
181                                CondPtr);
182
183      llvm::BasicBlock *TerminateHandler = CGF.getTerminateHandler();
184      llvm::BasicBlock *PrevLandingPad = CGF.getInvokeDest();
185      CGF.setInvokeDest(TerminateHandler);
186
187      // Stolen from EmitClassAggrMemberwiseCopy
188      llvm::Value *Callee = CGF.CGM.GetAddrOfCXXConstructor(CopyCtor,
189                                                            Ctor_Complete);
190      CallArgList CallArgs;
191      CallArgs.push_back(std::make_pair(RValue::get(This),
192                                      CopyCtor->getThisType(CGF.getContext())));
193
194      // Push the Src ptr.
195      CallArgs.push_back(std::make_pair(RValue::get(Src),
196                                        CopyCtor->getParamDecl(0)->getType()));
197      const FunctionProtoType *FPT
198        = CopyCtor->getType()->getAs<FunctionProtoType>();
199      CGF.EmitCall(CGF.CGM.getTypes().getFunctionInfo(CallArgs, FPT),
200                   Callee, ReturnValueSlot(), CallArgs, CopyCtor);
201      CGF.setInvokeDest(PrevLandingPad);
202    } else
203      llvm_unreachable("uncopyable object");
204  }
205}
206
207// CopyObject - Utility to copy an object.  Calls copy constructor as necessary.
208// N is casted to the right type.
209static void CopyObject(CodeGenFunction &CGF, QualType ObjectType,
210                       bool WasPointer, bool WasPointerReference,
211                       llvm::Value *E, llvm::Value *N) {
212  // Store the throw exception in the exception object.
213  if (WasPointer || !CGF.hasAggregateLLVMType(ObjectType)) {
214    llvm::Value *Value = E;
215    if (!WasPointer)
216      Value = CGF.Builder.CreateLoad(Value);
217    const llvm::Type *ValuePtrTy = Value->getType()->getPointerTo(0);
218    if (WasPointerReference) {
219      llvm::Value *Tmp = CGF.CreateTempAlloca(Value->getType(), "catch.param");
220      CGF.Builder.CreateStore(Value, Tmp);
221      Value = Tmp;
222      ValuePtrTy = Value->getType()->getPointerTo(0);
223    }
224    N = CGF.Builder.CreateBitCast(N, ValuePtrTy);
225    CGF.Builder.CreateStore(Value, N);
226  } else {
227    const llvm::Type *Ty = CGF.ConvertType(ObjectType)->getPointerTo(0);
228    const CXXRecordDecl *RD;
229    RD = cast<CXXRecordDecl>(ObjectType->getAs<RecordType>()->getDecl());
230    llvm::Value *This = CGF.Builder.CreateBitCast(N, Ty);
231    if (RD->hasTrivialCopyConstructor()) {
232      CGF.EmitAggregateCopy(This, E, ObjectType);
233    } else if (CXXConstructorDecl *CopyCtor
234               = RD->getCopyConstructor(CGF.getContext(), 0)) {
235      llvm::Value *Src = E;
236
237      // Stolen from EmitClassAggrMemberwiseCopy
238      llvm::Value *Callee = CGF.CGM.GetAddrOfCXXConstructor(CopyCtor,
239                                                            Ctor_Complete);
240      CallArgList CallArgs;
241      CallArgs.push_back(std::make_pair(RValue::get(This),
242                                      CopyCtor->getThisType(CGF.getContext())));
243
244      // Push the Src ptr.
245      CallArgs.push_back(std::make_pair(RValue::get(Src),
246                                        CopyCtor->getParamDecl(0)->getType()));
247
248      const FunctionProtoType *FPT
249        = CopyCtor->getType()->getAs<FunctionProtoType>();
250      CGF.EmitCall(CGF.CGM.getTypes().getFunctionInfo(CallArgs, FPT),
251                   Callee, ReturnValueSlot(), CallArgs, CopyCtor);
252    } else
253      llvm_unreachable("uncopyable object");
254  }
255}
256
257void CodeGenFunction::EmitCXXThrowExpr(const CXXThrowExpr *E) {
258  if (!E->getSubExpr()) {
259    if (getInvokeDest()) {
260      llvm::BasicBlock *Cont = createBasicBlock("invoke.cont");
261      Builder.CreateInvoke(getReThrowFn(*this), Cont, getInvokeDest())
262        ->setDoesNotReturn();
263      EmitBlock(Cont);
264    } else
265      Builder.CreateCall(getReThrowFn(*this))->setDoesNotReturn();
266    Builder.CreateUnreachable();
267
268    // Clear the insertion point to indicate we are in unreachable code.
269    Builder.ClearInsertionPoint();
270    return;
271  }
272
273  QualType ThrowType = E->getSubExpr()->getType();
274
275  // Now allocate the exception object.
276  const llvm::Type *SizeTy = ConvertType(getContext().getSizeType());
277  uint64_t TypeSize = getContext().getTypeSize(ThrowType) / 8;
278
279  llvm::Constant *AllocExceptionFn = getAllocateExceptionFn(*this);
280  llvm::Value *ExceptionPtr =
281    Builder.CreateCall(AllocExceptionFn,
282                       llvm::ConstantInt::get(SizeTy, TypeSize),
283                       "exception");
284
285  llvm::Value *ExceptionPtrPtr =
286    CreateTempAlloca(ExceptionPtr->getType(), "exception.ptr");
287  Builder.CreateStore(ExceptionPtr, ExceptionPtrPtr);
288
289
290  CopyObject(*this, E->getSubExpr(), ExceptionPtr, ExceptionPtrPtr);
291
292  // Now throw the exception.
293  const llvm::Type *Int8PtrTy = llvm::Type::getInt8PtrTy(getLLVMContext());
294  llvm::Constant *TypeInfo = CGM.GetAddrOfRTTIDescriptor(ThrowType);
295  llvm::Constant *Dtor = llvm::Constant::getNullValue(Int8PtrTy);
296
297  if (getInvokeDest()) {
298    llvm::BasicBlock *Cont = createBasicBlock("invoke.cont");
299    llvm::InvokeInst *ThrowCall =
300      Builder.CreateInvoke3(getThrowFn(*this), Cont, getInvokeDest(),
301                            ExceptionPtr, TypeInfo, Dtor);
302    ThrowCall->setDoesNotReturn();
303    EmitBlock(Cont);
304  } else {
305    llvm::CallInst *ThrowCall =
306      Builder.CreateCall3(getThrowFn(*this), ExceptionPtr, TypeInfo, Dtor);
307    ThrowCall->setDoesNotReturn();
308  }
309  Builder.CreateUnreachable();
310
311  // Clear the insertion point to indicate we are in unreachable code.
312  Builder.ClearInsertionPoint();
313
314  // FIXME: For now, emit a dummy basic block because expr emitters in generally
315  // are not ready to handle emitting expressions at unreachable points.
316  EnsureInsertPoint();
317}
318
319void CodeGenFunction::EmitStartEHSpec(const Decl *D) {
320  const FunctionDecl* FD = dyn_cast_or_null<FunctionDecl>(D);
321  if (FD == 0)
322    return;
323  const FunctionProtoType *Proto = FD->getType()->getAs<FunctionProtoType>();
324  if (Proto == 0)
325    return;
326
327  assert(!Proto->hasAnyExceptionSpec() && "function with parameter pack");
328
329  if (!Proto->hasExceptionSpec())
330    return;
331
332  llvm::Constant *Personality =
333    CGM.CreateRuntimeFunction(llvm::FunctionType::get(llvm::Type::getInt32Ty
334                                                      (VMContext),
335                                                      true),
336                              "__gxx_personality_v0");
337  Personality = llvm::ConstantExpr::getBitCast(Personality, PtrToInt8Ty);
338  llvm::Value *llvm_eh_exception =
339    CGM.getIntrinsic(llvm::Intrinsic::eh_exception);
340  llvm::Value *llvm_eh_selector =
341    CGM.getIntrinsic(llvm::Intrinsic::eh_selector);
342  const llvm::IntegerType *Int8Ty;
343  const llvm::PointerType *PtrToInt8Ty;
344  Int8Ty = llvm::Type::getInt8Ty(VMContext);
345  // C string type.  Used in lots of places.
346  PtrToInt8Ty = llvm::PointerType::getUnqual(Int8Ty);
347  llvm::Constant *Null = llvm::ConstantPointerNull::get(PtrToInt8Ty);
348  llvm::SmallVector<llvm::Value*, 8> SelectorArgs;
349
350  llvm::BasicBlock *PrevLandingPad = getInvokeDest();
351  llvm::BasicBlock *EHSpecHandler = createBasicBlock("ehspec.handler");
352  llvm::BasicBlock *Match = createBasicBlock("match");
353  llvm::BasicBlock *Unwind = 0;
354
355  assert(PrevLandingPad == 0 && "EHSpec has invoke context");
356  (void)PrevLandingPad;
357
358  llvm::BasicBlock *Cont = createBasicBlock("cont");
359
360  EmitBranchThroughCleanup(Cont);
361
362  // Emit the statements in the try {} block
363  setInvokeDest(EHSpecHandler);
364
365  EmitBlock(EHSpecHandler);
366  // Exception object
367  llvm::Value *Exc = Builder.CreateCall(llvm_eh_exception, "exc");
368  llvm::Value *RethrowPtr = CreateTempAlloca(Exc->getType(), "_rethrow");
369
370  SelectorArgs.push_back(Exc);
371  SelectorArgs.push_back(Personality);
372  SelectorArgs.push_back(llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext),
373                                                Proto->getNumExceptions()+1));
374
375  for (unsigned i = 0; i < Proto->getNumExceptions(); ++i) {
376    QualType Ty = Proto->getExceptionType(i);
377    QualType ExceptType
378      = Ty.getNonReferenceType().getUnqualifiedType();
379    llvm::Value *EHType = CGM.GetAddrOfRTTIDescriptor(ExceptType);
380    SelectorArgs.push_back(EHType);
381  }
382  if (Proto->getNumExceptions())
383    SelectorArgs.push_back(Null);
384
385  // Find which handler was matched.
386  llvm::Value *Selector
387    = Builder.CreateCall(llvm_eh_selector, SelectorArgs.begin(),
388                         SelectorArgs.end(), "selector");
389  if (Proto->getNumExceptions()) {
390    Unwind = createBasicBlock("Unwind");
391
392    Builder.CreateStore(Exc, RethrowPtr);
393    Builder.CreateCondBr(Builder.CreateICmpSLT(Selector,
394                                               llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext),
395                                                                      0)),
396                         Match, Unwind);
397
398    EmitBlock(Match);
399  }
400  Builder.CreateCall(getUnexpectedFn(*this), Exc)->setDoesNotReturn();
401  Builder.CreateUnreachable();
402
403  if (Proto->getNumExceptions()) {
404    EmitBlock(Unwind);
405    Builder.CreateCall(getUnwindResumeOrRethrowFn(*this),
406                       Builder.CreateLoad(RethrowPtr));
407    Builder.CreateUnreachable();
408  }
409
410  EmitBlock(Cont);
411}
412
413void CodeGenFunction::EmitEndEHSpec(const Decl *D) {
414  const FunctionDecl* FD = dyn_cast_or_null<FunctionDecl>(D);
415  if (FD == 0)
416    return;
417  const FunctionProtoType *Proto = FD->getType()->getAs<FunctionProtoType>();
418  if (Proto == 0)
419    return;
420
421  if (!Proto->hasExceptionSpec())
422    return;
423
424  setInvokeDest(0);
425}
426
427void CodeGenFunction::EmitCXXTryStmt(const CXXTryStmt &S) {
428  // Pointer to the personality function
429  llvm::Constant *Personality =
430    CGM.CreateRuntimeFunction(llvm::FunctionType::get(llvm::Type::getInt32Ty
431                                                      (VMContext),
432                                                      true),
433                              "__gxx_personality_v0");
434  Personality = llvm::ConstantExpr::getBitCast(Personality, PtrToInt8Ty);
435  llvm::Value *llvm_eh_exception =
436    CGM.getIntrinsic(llvm::Intrinsic::eh_exception);
437  llvm::Value *llvm_eh_selector =
438    CGM.getIntrinsic(llvm::Intrinsic::eh_selector);
439
440  llvm::BasicBlock *PrevLandingPad = getInvokeDest();
441  llvm::BasicBlock *TryHandler = createBasicBlock("try.handler");
442  llvm::BasicBlock *FinallyBlock = createBasicBlock("finally");
443  llvm::BasicBlock *FinallyRethrow = createBasicBlock("finally.throw");
444  llvm::BasicBlock *FinallyEnd = createBasicBlock("finally.end");
445
446  // Push an EH context entry, used for handling rethrows.
447  PushCleanupBlock(FinallyBlock);
448
449  // Emit the statements in the try {} block
450  setInvokeDest(TryHandler);
451
452  // FIXME: We should not have to do this here.  The AST should have the member
453  // initializers under the CXXTryStmt's TryBlock.
454  if (OuterTryBlock == &S) {
455    GlobalDecl GD = CurGD;
456    const FunctionDecl *FD = cast<FunctionDecl>(GD.getDecl());
457
458    if (const CXXConstructorDecl *CD = dyn_cast<CXXConstructorDecl>(FD)) {
459      size_t OldCleanupStackSize = CleanupEntries.size();
460      EmitCtorPrologue(CD, CurGD.getCtorType());
461      EmitStmt(S.getTryBlock());
462
463      // If any of the member initializers are temporaries bound to references
464      // make sure to emit their destructors.
465      EmitCleanupBlocks(OldCleanupStackSize);
466    } else if (const CXXDestructorDecl *DD = dyn_cast<CXXDestructorDecl>(FD)) {
467      llvm::BasicBlock *DtorEpilogue  = createBasicBlock("dtor.epilogue");
468      PushCleanupBlock(DtorEpilogue);
469
470      EmitStmt(S.getTryBlock());
471
472      CleanupBlockInfo Info = PopCleanupBlock();
473
474      assert(Info.CleanupBlock == DtorEpilogue && "Block mismatch!");
475      EmitBlock(DtorEpilogue);
476      EmitDtorEpilogue(DD, GD.getDtorType());
477
478      if (Info.SwitchBlock)
479        EmitBlock(Info.SwitchBlock);
480      if (Info.EndBlock)
481        EmitBlock(Info.EndBlock);
482    } else
483      EmitStmt(S.getTryBlock());
484  } else
485    EmitStmt(S.getTryBlock());
486
487  // Jump to end if there is no exception
488  EmitBranchThroughCleanup(FinallyEnd);
489
490  llvm::BasicBlock *TerminateHandler = getTerminateHandler();
491
492  // Emit the handlers
493  EmitBlock(TryHandler);
494
495  const llvm::IntegerType *Int8Ty;
496  const llvm::PointerType *PtrToInt8Ty;
497  Int8Ty = llvm::Type::getInt8Ty(VMContext);
498  // C string type.  Used in lots of places.
499  PtrToInt8Ty = llvm::PointerType::getUnqual(Int8Ty);
500  llvm::Constant *Null = llvm::ConstantPointerNull::get(PtrToInt8Ty);
501  llvm::SmallVector<llvm::Value*, 8> SelectorArgs;
502  llvm::Value *llvm_eh_typeid_for =
503    CGM.getIntrinsic(llvm::Intrinsic::eh_typeid_for);
504  // Exception object
505  llvm::Value *Exc = Builder.CreateCall(llvm_eh_exception, "exc");
506  llvm::Value *RethrowPtr = CreateTempAlloca(Exc->getType(), "_rethrow");
507
508  llvm::SmallVector<llvm::Value*, 8> Args;
509  Args.clear();
510  SelectorArgs.push_back(Exc);
511  SelectorArgs.push_back(Personality);
512
513  bool HasCatchAll = false;
514  for (unsigned i = 0; i<S.getNumHandlers(); ++i) {
515    const CXXCatchStmt *C = S.getHandler(i);
516    VarDecl *CatchParam = C->getExceptionDecl();
517    if (CatchParam) {
518      // C++ [except.handle]p3 indicates that top-level cv-qualifiers
519      // are ignored.
520      QualType CaughtType = C->getCaughtType().getNonReferenceType();
521      llvm::Value *EHTypeInfo
522        = CGM.GetAddrOfRTTIDescriptor(CaughtType.getUnqualifiedType());
523      SelectorArgs.push_back(EHTypeInfo);
524    } else {
525      // null indicates catch all
526      SelectorArgs.push_back(Null);
527      HasCatchAll = true;
528    }
529  }
530
531  // We use a cleanup unless there was already a catch all.
532  if (!HasCatchAll) {
533    SelectorArgs.push_back(Null);
534  }
535
536  // Find which handler was matched.
537  llvm::Value *Selector
538    = Builder.CreateCall(llvm_eh_selector, SelectorArgs.begin(),
539                         SelectorArgs.end(), "selector");
540  for (unsigned i = 0; i<S.getNumHandlers(); ++i) {
541    const CXXCatchStmt *C = S.getHandler(i);
542    VarDecl *CatchParam = C->getExceptionDecl();
543    Stmt *CatchBody = C->getHandlerBlock();
544
545    llvm::BasicBlock *Next = 0;
546
547    if (SelectorArgs[i+2] != Null) {
548      llvm::BasicBlock *Match = createBasicBlock("match");
549      Next = createBasicBlock("catch.next");
550      const llvm::Type *Int8PtrTy = llvm::Type::getInt8PtrTy(getLLVMContext());
551      llvm::Value *Id
552        = Builder.CreateCall(llvm_eh_typeid_for,
553                             Builder.CreateBitCast(SelectorArgs[i+2],
554                                                   Int8PtrTy));
555      Builder.CreateCondBr(Builder.CreateICmpEQ(Selector, Id),
556                           Match, Next);
557      EmitBlock(Match);
558    }
559
560    llvm::BasicBlock *MatchEnd = createBasicBlock("match.end");
561    llvm::BasicBlock *MatchHandler = createBasicBlock("match.handler");
562
563    PushCleanupBlock(MatchEnd);
564    setInvokeDest(MatchHandler);
565
566    llvm::Value *ExcObject = Builder.CreateCall(getBeginCatchFn(*this), Exc);
567
568    {
569      CleanupScope CatchScope(*this);
570      // Bind the catch parameter if it exists.
571      if (CatchParam) {
572        QualType CatchType = CatchParam->getType().getNonReferenceType();
573        setInvokeDest(TerminateHandler);
574        bool WasPointer = true;
575        bool WasPointerReference = false;
576        CatchType = CGM.getContext().getCanonicalType(CatchType);
577        if (CatchType.getTypePtr()->isPointerType()) {
578          if (isa<ReferenceType>(CatchParam->getType()))
579            WasPointerReference = true;
580        } else {
581          if (!isa<ReferenceType>(CatchParam->getType()))
582            WasPointer = false;
583          CatchType = getContext().getPointerType(CatchType);
584        }
585        ExcObject = Builder.CreateBitCast(ExcObject, ConvertType(CatchType));
586        EmitLocalBlockVarDecl(*CatchParam);
587        // FIXME: we need to do this sooner so that the EH region for the
588        // cleanup doesn't start until after the ctor completes, use a decl
589        // init?
590        CopyObject(*this, CatchParam->getType().getNonReferenceType(),
591                   WasPointer, WasPointerReference, ExcObject,
592                   GetAddrOfLocalVar(CatchParam));
593        setInvokeDest(MatchHandler);
594      }
595
596      EmitStmt(CatchBody);
597    }
598
599    EmitBranchThroughCleanup(FinallyEnd);
600
601    EmitBlock(MatchHandler);
602
603    llvm::Value *Exc = Builder.CreateCall(llvm_eh_exception, "exc");
604    // We are required to emit this call to satisfy LLVM, even
605    // though we don't use the result.
606    Args.clear();
607    Args.push_back(Exc);
608    Args.push_back(Personality);
609    Args.push_back(llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext),
610                                          0));
611    Builder.CreateCall(llvm_eh_selector, Args.begin(), Args.end());
612    Builder.CreateStore(Exc, RethrowPtr);
613    EmitBranchThroughCleanup(FinallyRethrow);
614
615    CodeGenFunction::CleanupBlockInfo Info = PopCleanupBlock();
616
617    EmitBlock(MatchEnd);
618
619    llvm::BasicBlock *Cont = createBasicBlock("invoke.cont");
620    Builder.CreateInvoke(getEndCatchFn(*this),
621                         Cont, TerminateHandler,
622                         Args.begin(), Args.begin());
623    EmitBlock(Cont);
624    if (Info.SwitchBlock)
625      EmitBlock(Info.SwitchBlock);
626    if (Info.EndBlock)
627      EmitBlock(Info.EndBlock);
628
629    Exc = Builder.CreateCall(llvm_eh_exception, "exc");
630    Builder.CreateStore(Exc, RethrowPtr);
631    EmitBranchThroughCleanup(FinallyRethrow);
632
633    if (Next)
634      EmitBlock(Next);
635  }
636  if (!HasCatchAll) {
637    Builder.CreateStore(Exc, RethrowPtr);
638    EmitBranchThroughCleanup(FinallyRethrow);
639  }
640
641  CodeGenFunction::CleanupBlockInfo Info = PopCleanupBlock();
642
643  setInvokeDest(PrevLandingPad);
644
645  EmitBlock(FinallyBlock);
646
647  if (Info.SwitchBlock)
648    EmitBlock(Info.SwitchBlock);
649  if (Info.EndBlock)
650    EmitBlock(Info.EndBlock);
651
652  // Branch around the rethrow code.
653  EmitBranch(FinallyEnd);
654
655  EmitBlock(FinallyRethrow);
656  // FIXME: Eventually we can chain the handlers together and just do a call
657  // here.
658  if (getInvokeDest()) {
659    llvm::BasicBlock *Cont = createBasicBlock("invoke.cont");
660    Builder.CreateInvoke(getUnwindResumeOrRethrowFn(*this), Cont,
661                         getInvokeDest(),
662                         Builder.CreateLoad(RethrowPtr));
663    EmitBlock(Cont);
664  } else
665    Builder.CreateCall(getUnwindResumeOrRethrowFn(*this),
666                       Builder.CreateLoad(RethrowPtr));
667
668  Builder.CreateUnreachable();
669
670  EmitBlock(FinallyEnd);
671}
672
673CodeGenFunction::EHCleanupBlock::~EHCleanupBlock() {
674  llvm::BasicBlock *Cont1 = CGF.createBasicBlock("cont");
675  CGF.EmitBranch(Cont1);
676  CGF.setInvokeDest(PreviousInvokeDest);
677
678
679  CGF.EmitBlock(CleanupHandler);
680
681  llvm::Constant *Personality =
682    CGF.CGM.CreateRuntimeFunction(llvm::FunctionType::get(llvm::Type::getInt32Ty
683                                                          (CGF.VMContext),
684                                                          true),
685                                  "__gxx_personality_v0");
686  Personality = llvm::ConstantExpr::getBitCast(Personality, CGF.PtrToInt8Ty);
687  llvm::Value *llvm_eh_exception =
688    CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_exception);
689  llvm::Value *llvm_eh_selector =
690    CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_selector);
691
692  llvm::Value *Exc = CGF.Builder.CreateCall(llvm_eh_exception, "exc");
693  const llvm::IntegerType *Int8Ty;
694  const llvm::PointerType *PtrToInt8Ty;
695  Int8Ty = llvm::Type::getInt8Ty(CGF.VMContext);
696  // C string type.  Used in lots of places.
697  PtrToInt8Ty = llvm::PointerType::getUnqual(Int8Ty);
698  llvm::Constant *Null = llvm::ConstantPointerNull::get(PtrToInt8Ty);
699  llvm::SmallVector<llvm::Value*, 8> Args;
700  Args.clear();
701  Args.push_back(Exc);
702  Args.push_back(Personality);
703  Args.push_back(Null);
704  CGF.Builder.CreateCall(llvm_eh_selector, Args.begin(), Args.end());
705
706  CGF.EmitBlock(CleanupEntryBB);
707
708  CGF.EmitBlock(Cont1);
709
710  if (CGF.getInvokeDest()) {
711    llvm::BasicBlock *Cont = CGF.createBasicBlock("invoke.cont");
712    CGF.Builder.CreateInvoke(getUnwindResumeOrRethrowFn(CGF), Cont,
713                             CGF.getInvokeDest(), Exc);
714    CGF.EmitBlock(Cont);
715  } else
716    CGF.Builder.CreateCall(getUnwindResumeOrRethrowFn(CGF), Exc);
717
718  CGF.Builder.CreateUnreachable();
719
720  CGF.EmitBlock(Cont);
721  if (CGF.Exceptions)
722    CGF.setInvokeDest(CleanupHandler);
723}
724
725llvm::BasicBlock *CodeGenFunction::getTerminateHandler() {
726  if (TerminateHandler)
727    return TerminateHandler;
728
729  llvm::BasicBlock *Cont = 0;
730
731  if (HaveInsertPoint()) {
732    Cont = createBasicBlock("cont");
733    EmitBranch(Cont);
734  }
735
736  llvm::Constant *Personality =
737    CGM.CreateRuntimeFunction(llvm::FunctionType::get(llvm::Type::getInt32Ty
738                                                      (VMContext),
739                                                      true),
740                              "__gxx_personality_v0");
741  Personality = llvm::ConstantExpr::getBitCast(Personality, PtrToInt8Ty);
742  llvm::Value *llvm_eh_exception =
743    CGM.getIntrinsic(llvm::Intrinsic::eh_exception);
744  llvm::Value *llvm_eh_selector =
745    CGM.getIntrinsic(llvm::Intrinsic::eh_selector);
746
747  // Set up terminate handler
748  TerminateHandler = createBasicBlock("terminate.handler");
749  EmitBlock(TerminateHandler);
750  llvm::Value *Exc = Builder.CreateCall(llvm_eh_exception, "exc");
751  // We are required to emit this call to satisfy LLVM, even
752  // though we don't use the result.
753  llvm::SmallVector<llvm::Value*, 8> Args;
754  Args.push_back(Exc);
755  Args.push_back(Personality);
756  Args.push_back(llvm::ConstantInt::get(llvm::Type::getInt32Ty(VMContext),
757                                        1));
758  Builder.CreateCall(llvm_eh_selector, Args.begin(), Args.end());
759  llvm::CallInst *TerminateCall =
760    Builder.CreateCall(getTerminateFn(*this));
761  TerminateCall->setDoesNotReturn();
762  TerminateCall->setDoesNotThrow();
763  Builder.CreateUnreachable();
764
765  // Clear the insertion point to indicate we are in unreachable code.
766  Builder.ClearInsertionPoint();
767
768  if (Cont)
769    EmitBlock(Cont);
770
771  return TerminateHandler;
772}
773