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Simplify generate code for exceptions: 

- There is no need to branch on the rethrow variable to determine if
   we need to call objc_exception_try_exit. We know whether an
   exception was thrown, so just branch to a different target if we
   want to skip the try_exit. 

   This is a slight semantic departure from gcc, but only for throwing
   nil, which is undefined (and for which gcc emits broken code).

 - Also fixes a bug in current code which was calling try_exit too
   many times when an exception was uncaught (but there were some
   handlers).

Fix bug introduced in prev. commit, the type of the @catch parameter
was uninitialized.

llvm-svn: 56754
This commit is contained in:
Daniel Dunbar 2008-09-27 07:36:24 +00:00
parent aec553bfdb
commit 523208fb4a
1 changed files with 16 additions and 28 deletions
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44
clang/lib/CodeGen/CGObjCMac.cpp
View File

@ -1405,6 +1405,7 @@ void CGObjCMac::EmitTryStmt(CodeGen::CodeGenFunction &CGF,
llvm::BasicBlock *FinallyBlock = llvm::BasicBlock::Create("finally");
llvm::BasicBlock *FinallyNoExit = llvm::BasicBlock::Create("finally.noexit");
llvm::BasicBlock *TryBlock = llvm::BasicBlock::Create("try");
llvm::BasicBlock *ExceptionInTryBlock =
@ -1455,19 +1456,19 @@ void CGObjCMac::EmitTryStmt(CodeGen::CodeGenFunction &CGF,
for (; CatchStmt; CatchStmt = CatchStmt->getNextCatchStmt()) {
llvm::BasicBlock *NextCatchBlock = llvm::BasicBlock::Create("nextcatch");
QualType T;
const DeclStmt *CatchParam =
cast_or_null<DeclStmt>(CatchStmt->getCatchParamStmt());
const ValueDecl *VD = 0;
const VarDecl *VD = 0;
const PointerType *PT = 0;
// catch(...) always matches.
if (!CatchParam) {
AllMatched = true;
} else {
VD = cast<ValueDecl>(CatchParam->getDecl());
VD = cast<VarDecl>(CatchParam->getDecl());
PT = VD->getType()->getAsPointerType();
// catch(id e) always matches.
const PointerType *PT = VD->getType()->getAsPointerType();
if (PT && CGF.getContext().isObjCIdType(PT->getPointeeType()))
AllMatched = true;
}
@ -1475,12 +1476,7 @@ void CGObjCMac::EmitTryStmt(CodeGen::CodeGenFunction &CGF,
if (AllMatched) {
if (CatchParam) {
CGF.EmitStmt(CatchParam);
const VarDecl *VD = cast<VarDecl>(CatchParam->getDecl());
llvm::Value *V = CGF.GetAddrOfLocalVar(VD);
CGF.Builder.CreateStore(Caught, V);
CGF.Builder.CreateStore(Caught, CGF.GetAddrOfLocalVar(VD));
}
CGF.EmitStmt(CatchStmt->getCatchBody());
@ -1488,6 +1484,8 @@ void CGObjCMac::EmitTryStmt(CodeGen::CodeGenFunction &CGF,
break;
}
assert(PT && "Unexpected non-pointer type in @catch");
QualType T = PT->getPointeeType();
const ObjCInterfaceType *ObjCType = T->getAsObjCInterfaceType();
assert(ObjCType && "Catch parameter must have Objective-C type!");
@ -1508,8 +1506,6 @@ void CGObjCMac::EmitTryStmt(CodeGen::CodeGenFunction &CGF,
if (CatchParam) {
CGF.EmitStmt(CatchParam);
const VarDecl *VD = cast<VarDecl>(CatchParam->getDecl());
llvm::Value *Tmp =
CGF.Builder.CreateBitCast(Caught, CGF.ConvertType(VD->getType()),
"tmp");
@ -1526,7 +1522,6 @@ void CGObjCMac::EmitTryStmt(CodeGen::CodeGenFunction &CGF,
// None of the handlers caught the exception, so store it to be
// rethrown at the end of the @finally block.
CGF.Builder.CreateStore(Caught, RethrowPtr);
CGF.Builder.CreateCall(ObjCTypes.ExceptionTryExitFn, ExceptionData);
CGF.Builder.CreateBr(FinallyBlock);
}
@ -1535,30 +1530,23 @@ void CGObjCMac::EmitTryStmt(CodeGen::CodeGenFunction &CGF,
CGF.Builder.CreateStore(CGF.Builder.CreateCall(ObjCTypes.ExceptionExtractFn,
ExceptionData),
RethrowPtr);
CGF.Builder.CreateBr(FinallyNoExit);
} else {
CGF.Builder.CreateStore(Caught, RethrowPtr);
CGF.Builder.CreateBr(FinallyNoExit);
}
// Emit the @finally block.
CGF.EmitBlock(FinallyBlock);
llvm::Value *Rethrow = CGF.Builder.CreateLoad(RethrowPtr);
llvm::Value *ZeroPtr = llvm::Constant::getNullValue(ObjCTypes.ObjectPtrTy);
llvm::Value *RethrowIsZero = CGF.Builder.CreateICmpEQ(Rethrow, ZeroPtr);
llvm::BasicBlock *TryExitBlock = llvm::BasicBlock::Create("tryexit");
llvm::BasicBlock *AfterTryExitBlock =
llvm::BasicBlock::Create("aftertryexit");
CGF.Builder.CreateCondBr(RethrowIsZero, TryExitBlock, AfterTryExitBlock);
CGF.EmitBlock(TryExitBlock);
CGF.Builder.CreateCall(ObjCTypes.ExceptionTryExitFn, ExceptionData);
CGF.EmitBlock(AfterTryExitBlock);
CGF.EmitBlock(FinallyNoExit);
if (const ObjCAtFinallyStmt* FinallyStmt = S.getFinallyStmt())
CGF.EmitStmt(FinallyStmt->getFinallyBody());
llvm::Value *Rethrow = CGF.Builder.CreateLoad(RethrowPtr);
llvm::Value *ZeroPtr = llvm::Constant::getNullValue(ObjCTypes.ObjectPtrTy);
llvm::Value *RethrowIsNotZero = CGF.Builder.CreateICmpNE(Rethrow, ZeroPtr);
llvm::BasicBlock *RethrowBlock = llvm::BasicBlock::Create("rethrow");