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Initial code to convert ResumeInsts into calls to _Unwind_Resume.

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This should be the only code necessary for DWARF EH prepare.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@136387 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Bill Wendling 2011-07-28 20:48:05 +00:00
parent af7a46d5a6
commit b4904503de
1 changed files with 57 additions and 1 deletions
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58
lib/CodeGen/DwarfEHPrepare.cpp
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@ -63,6 +63,8 @@ namespace {
typedef SmallPtrSet<BasicBlock*, 8> BBSet;
BBSet LandingPads;
bool InsertUnwindResumeCalls();
bool NormalizeLandingPads();
bool LowerUnwindsAndResumes();
bool MoveExceptionValueCalls();
@ -658,13 +660,67 @@ Instruction *DwarfEHPrepare::CreateExceptionValueCall(BasicBlock *BB) {
return CallInst::Create(ExceptionValueIntrinsic, "eh.value.call", Start);
}
/// InsertUnwindResumeCalls - Convert the ResumeInsts that are still present
/// into calls to the appropriate _Unwind_Resume function.
bool DwarfEHPrepare::InsertUnwindResumeCalls() {
SmallVector<ResumeInst*, 16> Resumes;
for (Function::iterator I = F->begin(), E = F->end(); I != E; ++I)
for (BasicBlock::iterator II = I->begin(), IE = I->end(); II != IE; ++II)
if (ResumeInst *RI = dyn_cast<ResumeInst>(II))
Resumes.push_back(RI);
if (Resumes.empty())
return false;
// Find the rewind function if we didn't already.
if (!RewindFunction) {
LLVMContext &Ctx = Resumes[0]->getContext();
FunctionType *FTy = FunctionType::get(Type::getVoidTy(Ctx),
Type::getInt8PtrTy(Ctx), false);
const char *RewindName = TLI->getLibcallName(RTLIB::UNWIND_RESUME);
RewindFunction = F->getParent()->getOrInsertFunction(RewindName, FTy);
}
// Create the basic block where the _Unwind_Resume call will live.
LLVMContext &Ctx = F->getContext();
BasicBlock *UnwindBB = BasicBlock::Create(Ctx, "unwind_resume", F);
PHINode *PN = PHINode::Create(Type::getInt8PtrTy(Ctx), Resumes.size(),
"exn.obj", UnwindBB);
// Extract the exception object from the ResumeInst and add it to the PHI node
// that feeds the _Unwind_Resume call.
for (SmallVectorImpl<ResumeInst*>::iterator
I = Resumes.begin(), E = Resumes.end(); I != E; ++I) {
ResumeInst *RI = *I;
BranchInst::Create(UnwindBB, RI->getParent());
ExtractValueInst *ExnObj = ExtractValueInst::Create(RI->getOperand(0),
0, "exn.obj", RI);
PN->addIncoming(ExnObj, RI->getParent());
RI->eraseFromParent();
}
// Call the function.
CallInst *CI = CallInst::Create(RewindFunction, PN, "", UnwindBB);
CI->setCallingConv(TLI->getLibcallCallingConv(RTLIB::UNWIND_RESUME));
// We never expect _Unwind_Resume to return.
new UnreachableInst(Ctx, UnwindBB);
return true;
}
bool DwarfEHPrepare::runOnFunction(Function &Fn) {
bool Changed = false;
// Initialize internal state.
DT = &getAnalysis<DominatorTree>();
DT = &getAnalysis<DominatorTree>(); // FIXME: We won't need this with the new EH.
F = &Fn;
if (InsertUnwindResumeCalls()) {
// FIXME: The reset of this function can go once the new EH is done.
LandingPads.clear();
return true;
}
// Ensure that only unwind edges end at landing pads (a landing pad is a
// basic block where an invoke unwind edge ends).
Changed |= NormalizeLandingPads();