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First cut at zero-cost EH support. 

- Still manually generates the EH code; the parts related to cleanup
   need to be integrated into the cleanup stack (for proper
   interaction with VLAs, etc.).

 - Some differences vs gcc in corner cases; I believe our behavior is
   correct but need to verify/file bugs vs gcc.

llvm-svn: 65809
This commit is contained in:
Daniel Dunbar 2009-03-02 06:08:11 +00:00
parent 7a38ce4f88
commit 76b7acc49f
1 changed files with 210 additions and 72 deletions
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282
clang/lib/CodeGen/CGObjCMac.cpp
View File

@ -614,12 +614,13 @@ private:
ObjCNonFragileABITypesHelper ObjCTypes;
llvm::GlobalVariable* ObjCEmptyCacheVar;
llvm::GlobalVariable* ObjCEmptyVtableVar;
/// MetaClassReferences - uniqued meta class references.
llvm::DenseMap<IdentifierInfo*, llvm::GlobalVariable*> MetaClassReferences;
/// EHTypeReferences - uniqued class ehtype references.
llvm::DenseMap<IdentifierInfo*, llvm::GlobalVariable*> EHTypeReferences;
/// FinishNonFragileABIModule - Write out global data structures at the end of
/// processing a translation unit.
void FinishNonFragileABIModule();
@ -708,7 +709,7 @@ private:
/// GetInterfaceEHType - Get the ehtype for the given Objective-C
/// interface. The return value has type EHTypePtrTy.
llvm::Value *GetInterfaceEHType(const ObjCInterfaceType *IT);
public:
CGObjCNonFragileABIMac(CodeGen::CodeGenModule &cgm);
// FIXME. All stubs for now!
@ -3383,7 +3384,6 @@ ObjCNonFragileABITypesHelper::ObjCNonFragileABITypesHelper(CodeGen::CodeGenModul
"__objc_personality_v0");
EHPersonalityPtr = llvm::ConstantExpr::getBitCast(Personality, Int8PtrTy);
Params.clear();
Params.push_back(Int8PtrTy);
UnwindResumeOrRethrowFn =
@ -3413,7 +3413,7 @@ ObjCNonFragileABITypesHelper::ObjCNonFragileABITypesHelper(CodeGen::CodeGenModul
Int8PtrTy,
ClassnfABIPtrTy,
NULL);
CGM.getModule().addTypeName("struct._objc_typeinfo", CategorynfABITy);
CGM.getModule().addTypeName("struct._objc_typeinfo", EHTypeTy);
EHTypePtrTy = llvm::PointerType::getUnqual(EHTypeTy);
}
@ -4729,16 +4729,12 @@ void CGObjCNonFragileABIMac::EmitObjCGlobalAssign(CodeGen::CodeGenFunction &CGF,
void
CGObjCNonFragileABIMac::EmitTryOrSynchronizedStmt(CodeGen::CodeGenFunction &CGF,
const Stmt &S) {
// We don't handle anything interesting yet.
if (const ObjCAtTryStmt *TS = dyn_cast<ObjCAtTryStmt>(&S))
if (TS->getCatchStmts())
return CGF.ErrorUnsupported(&S, "try (with catch) statement");
bool isTry = isa<ObjCAtTryStmt>(S);
llvm::BasicBlock *TryBlock = CGF.createBasicBlock("try");
llvm::BasicBlock *PrevLandingPad = CGF.getInvokeDest();
llvm::BasicBlock *LandingPad = CGF.createBasicBlock("try.pad");
llvm::BasicBlock *TryHandler = CGF.createBasicBlock("try.handler");
llvm::BasicBlock *FinallyBlock = CGF.createBasicBlock("finally");
llvm::BasicBlock *FinallyRethrow = CGF.createBasicBlock("finally.throw");
llvm::BasicBlock *FinallyEnd = CGF.createBasicBlock("finally.end");
// For @synchronized, call objc_sync_enter(sync.expr). The
@ -4757,13 +4753,193 @@ CGObjCNonFragileABIMac::EmitTryOrSynchronizedStmt(CodeGen::CodeGenFunction &CGF,
// through finally.
CGF.PushCleanupBlock(FinallyBlock);
CGF.setInvokeDest(LandingPad);
CGF.setInvokeDest(TryHandler);
CGF.EmitBlock(TryBlock);
CGF.EmitStmt(isTry ? cast<ObjCAtTryStmt>(S).getTryBody()
: cast<ObjCAtSynchronizedStmt>(S).getSynchBody());
CGF.EmitBranchThroughCleanup(FinallyEnd);
// Emit the exception handler.
CGF.EmitBlock(TryHandler);
llvm::Value *llvm_eh_exception =
CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_exception);
llvm::Value *llvm_eh_selector_i64 =
CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_selector_i64);
llvm::Value *llvm_eh_typeid_for_i64 =
CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_typeid_for_i64);
llvm::Value *Exc = CGF.Builder.CreateCall(llvm_eh_exception, "exc");
llvm::Value *RethrowPtr = CGF.CreateTempAlloca(Exc->getType(), "_rethrow");
llvm::SmallVector<llvm::Value*, 8> SelectorArgs;
SelectorArgs.push_back(Exc);
SelectorArgs.push_back(ObjCTypes.EHPersonalityPtr);
// Construct the lists of (type, catch body) to handle.
llvm::SmallVector<std::pair<const DeclStmt*, const Stmt*>, 8> Handlers;
bool HasCatchAll = false;
if (isTry) {
if (const ObjCAtCatchStmt* CatchStmt =
cast<ObjCAtTryStmt>(S).getCatchStmts()) {
for (; CatchStmt; CatchStmt = CatchStmt->getNextCatchStmt()) {
const DeclStmt *DS = CatchStmt->getCatchParamStmt();
Handlers.push_back(std::make_pair(DS, CatchStmt->getCatchBody()));
// catch(...) always matches.
if (!DS) {
// Use i8* null here to signal this is a catch all, not a cleanup.
llvm::Value *Null = llvm::Constant::getNullValue(ObjCTypes.Int8PtrTy);
SelectorArgs.push_back(Null);
HasCatchAll = true;
break;
}
const VarDecl *VD = cast<VarDecl>(DS->getSolitaryDecl());
if (CGF.getContext().isObjCIdType(VD->getType()) ||
VD->getType()->isObjCQualifiedIdType()) {
llvm::Value *IDEHType =
CGM.getModule().getGlobalVariable("OBJC_EHTYPE_id");
if (!IDEHType)
IDEHType =
new llvm::GlobalVariable(ObjCTypes.EHTypeTy, false,
llvm::GlobalValue::ExternalLinkage,
0, "OBJC_EHTYPE_id", &CGM.getModule());
SelectorArgs.push_back(IDEHType);
HasCatchAll = true;
break;
}
// All other types should be Objective-C interface pointer types.
const PointerType *PT = VD->getType()->getAsPointerType();
assert(PT && "Invalid @catch type.");
const ObjCInterfaceType *IT =
PT->getPointeeType()->getAsObjCInterfaceType();
assert(IT && "Invalid @catch type.");
llvm::Value *EHType = GetInterfaceEHType(IT);
SelectorArgs.push_back(EHType);
}
}
}
// We use a cleanup unless there was already a catch all.
if (!HasCatchAll) {
SelectorArgs.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, 0));
Handlers.push_back(std::make_pair((const DeclStmt*) 0, (const Stmt*) 0));
}
llvm::Value *Selector =
CGF.Builder.CreateCall(llvm_eh_selector_i64,
SelectorArgs.begin(), SelectorArgs.end(),
"selector");
for (unsigned i = 0, e = Handlers.size(); i != e; ++i) {
const DeclStmt *CatchParam = Handlers[i].first;
const Stmt *CatchBody = Handlers[i].second;
llvm::BasicBlock *Next = 0;
// The last handler always matches.
if (i + 1 != e) {
assert(CatchParam && "Only last handler can be a catch all.");
llvm::BasicBlock *Match = CGF.createBasicBlock("match");
Next = CGF.createBasicBlock("catch.next");
llvm::Value *Id =
CGF.Builder.CreateCall(llvm_eh_typeid_for_i64,
CGF.Builder.CreateBitCast(SelectorArgs[i+2],
ObjCTypes.Int8PtrTy));
CGF.Builder.CreateCondBr(CGF.Builder.CreateICmpEQ(Selector, Id),
Match, Next);
CGF.EmitBlock(Match);
}
if (CatchBody) {
llvm::BasicBlock *MatchEnd = CGF.createBasicBlock("match.end");
llvm::BasicBlock *MatchHandler = CGF.createBasicBlock("match.handler");
// Cleanups must call objc_end_catch.
//
// FIXME: It seems incorrect for objc_begin_catch to be inside
// this context, but this matches gcc.
CGF.PushCleanupBlock(MatchEnd);
CGF.setInvokeDest(MatchHandler);
llvm::Value *ExcObject =
CGF.Builder.CreateCall(ObjCTypes.ObjCBeginCatchFn, Exc);
// Bind the catch parameter if it exists.
if (CatchParam) {
const VarDecl *VD = cast<VarDecl>(CatchParam->getSolitaryDecl());
ExcObject = CGF.Builder.CreateBitCast(ExcObject,
CGF.ConvertType(VD->getType()));
CGF.EmitStmt(CatchParam);
CGF.Builder.CreateStore(ExcObject, CGF.GetAddrOfLocalVar(VD));
}
CGF.ObjCEHValueStack.push_back(ExcObject);
CGF.EmitStmt(CatchBody);
CGF.ObjCEHValueStack.pop_back();
CGF.EmitBranchThroughCleanup(FinallyEnd);
CGF.EmitBlock(MatchHandler);
llvm::Value *Exc = CGF.Builder.CreateCall(llvm_eh_exception, "exc");
// We are required to emit this call to satisfy LLVM, even
// though we don't use the result.
llvm::SmallVector<llvm::Value*, 8> Args;
Args.push_back(Exc);
Args.push_back(ObjCTypes.EHPersonalityPtr);
Args.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty,
0));
CGF.Builder.CreateCall(llvm_eh_selector_i64, Args.begin(), Args.end());
CGF.Builder.CreateStore(Exc, RethrowPtr);
CGF.EmitBranchThroughCleanup(FinallyRethrow);
CodeGenFunction::CleanupBlockInfo Info = CGF.PopCleanupBlock();
CGF.EmitBlock(MatchEnd);
// Unfortunately, we also have to generate another EH frame here
// in case this throws.
llvm::BasicBlock *MatchEndHandler =
CGF.createBasicBlock("match.end.handler");
llvm::BasicBlock *Cont = CGF.createBasicBlock("invoke.cont");
CGF.Builder.CreateInvoke(ObjCTypes.ObjCEndCatchFn,
Cont, MatchEndHandler,
Args.begin(), Args.begin());
CGF.EmitBlock(Cont);
if (Info.SwitchBlock)
CGF.EmitBlock(Info.SwitchBlock);
if (Info.EndBlock)
CGF.EmitBlock(Info.EndBlock);
CGF.EmitBlock(MatchEndHandler);
Exc = CGF.Builder.CreateCall(llvm_eh_exception, "exc");
// We are required to emit this call to satisfy LLVM, even
// though we don't use the result.
Args.clear();
Args.push_back(Exc);
Args.push_back(ObjCTypes.EHPersonalityPtr);
Args.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty,
0));
CGF.Builder.CreateCall(llvm_eh_selector_i64, Args.begin(), Args.end());
CGF.Builder.CreateStore(Exc, RethrowPtr);
CGF.EmitBranchThroughCleanup(FinallyRethrow);
if (Next)
CGF.EmitBlock(Next);
} else {
assert(!Next && "catchup should be last handler.");
CGF.Builder.CreateStore(Exc, RethrowPtr);
CGF.EmitBranchThroughCleanup(FinallyRethrow);
}
}
// Pop the cleanup entry, the @finally is outside this cleanup
// scope.
CodeGenFunction::CleanupBlockInfo Info = CGF.PopCleanupBlock();
@ -4779,57 +4955,19 @@ CGObjCNonFragileABIMac::EmitTryOrSynchronizedStmt(CodeGen::CodeGenFunction &CGF,
// Emit 'objc_sync_exit(expr)' as finally's sole statement for
// @synchronized.
CGF.Builder.CreateCall(ObjCTypes.SyncExitFn, SyncArg);
}
}
if (Info.SwitchBlock)
CGF.EmitBlock(Info.SwitchBlock);
if (Info.EndBlock)
CGF.EmitBlock(Info.EndBlock);
// Branch around the landing pad if necessary.
// Branch around the rethrow code.
CGF.EmitBranch(FinallyEnd);
// Emit the landing pad.
// Clear insertion point to avoid chaining.
CGF.Builder.ClearInsertionPoint();
CGF.EmitBlock(LandingPad);
llvm::Value *llvm_eh_exception =
CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_exception);
llvm::Value *llvm_eh_selector_i64 =
CGF.CGM.getIntrinsic(llvm::Intrinsic::eh_selector_i64);
llvm::Value *Exc = CGF.Builder.CreateCall(llvm_eh_exception, "exc");
llvm::SmallVector<llvm::Value*, 8> Args;
Args.push_back(Exc);
Args.push_back(ObjCTypes.EHPersonalityPtr);
Args.push_back(llvm::ConstantInt::get(llvm::Type::Int32Ty, 0));
llvm::Value *Selector =
CGF.Builder.CreateCall(llvm_eh_selector_i64, Args.begin(), Args.end());
// The only valid result for the limited case we are considering is
// the cleanup.
(void) Selector;
// Re-emit cleanup code for exceptional case.
if (isTry) {
// FIXME: This is horrible, in many ways: (a) it is broken because
// we are messing with some global data structures (like where
// labels point at), (b) it is exponential in the size of code
// generated, (c) seriously, its just gross.
if (const ObjCAtFinallyStmt* FinallyStmt =
cast<ObjCAtTryStmt>(S).getFinallyStmt())
CGF.EmitStmt(FinallyStmt->getFinallyBody());
} else {
// Emit 'objc_sync_exit(expr)' as finally's sole statement for
// @synchronized.
CGF.Builder.CreateCall(ObjCTypes.SyncExitFn, SyncArg);
}
CGF.EnsureInsertPoint();
CGF.Builder.CreateCall(ObjCTypes.UnwindResumeOrRethrowFn, Exc);
CGF.EmitBlock(FinallyRethrow);
CGF.Builder.CreateCall(ObjCTypes.UnwindResumeOrRethrowFn,
CGF.Builder.CreateLoad(RethrowPtr));
CGF.Builder.CreateUnreachable();
CGF.EmitBlock(FinallyEnd);
@ -4838,28 +4976,28 @@ CGObjCNonFragileABIMac::EmitTryOrSynchronizedStmt(CodeGen::CodeGenFunction &CGF,
/// EmitThrowStmt - Generate code for a throw statement.
void CGObjCNonFragileABIMac::EmitThrowStmt(CodeGen::CodeGenFunction &CGF,
const ObjCAtThrowStmt &S) {
llvm::Value *ExceptionAsObject;
llvm::Value *Exception;
if (const Expr *ThrowExpr = S.getThrowExpr()) {
llvm::Value *Exception = CGF.EmitScalarExpr(ThrowExpr);
ExceptionAsObject =
CGF.Builder.CreateBitCast(Exception, ObjCTypes.ObjectPtrTy, "tmp");
llvm::BasicBlock *InvokeDest = CGF.getInvokeDest();
if (InvokeDest) {
llvm::BasicBlock *Cont = CGF.createBasicBlock("invoke.cont");
CGF.Builder.CreateInvoke(ObjCTypes.ExceptionThrowFn,
Cont, InvokeDest,
&ExceptionAsObject, &ExceptionAsObject + 1);
CGF.EmitBlock(Cont);
} else
CGF.Builder.CreateCall(ObjCTypes.ExceptionThrowFn, ExceptionAsObject);
CGF.Builder.CreateUnreachable();
Exception = CGF.EmitScalarExpr(ThrowExpr);
} else {
CGF.ErrorUnsupported(&S, "rethrow statement");
assert((!CGF.ObjCEHValueStack.empty() && CGF.ObjCEHValueStack.back()) &&
"Unexpected rethrow outside @catch block.");
Exception = CGF.ObjCEHValueStack.back();
}
llvm::Value *ExceptionAsObject =
CGF.Builder.CreateBitCast(Exception, ObjCTypes.ObjectPtrTy, "tmp");
llvm::BasicBlock *InvokeDest = CGF.getInvokeDest();
if (InvokeDest) {
llvm::BasicBlock *Cont = CGF.createBasicBlock("invoke.cont");
CGF.Builder.CreateInvoke(ObjCTypes.ExceptionThrowFn,
Cont, InvokeDest,
&ExceptionAsObject, &ExceptionAsObject + 1);
CGF.EmitBlock(Cont);
} else
CGF.Builder.CreateCall(ObjCTypes.ExceptionThrowFn, ExceptionAsObject);
CGF.Builder.CreateUnreachable();
// Clear the insertion point to indicate we are in unreachable code.
CGF.Builder.ClearInsertionPoint();
}