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There are some situations which can cause the URoR hack to infinitely recurse 

and then go kablooie. The problem was that it was tracking the PHI nodes anew
each time into this function. But it didn't need to. And because the recursion
didn't know that a PHINode was visited before, it would go ahead and call
itself.

There is a testcase, but unfortunately it's too big to add. This problem will go
away with the EH rewrite.
<rdar://problem/8856298>

llvm-svn: 127640
This commit is contained in:
Bill Wendling 2011-03-15 01:03:17 +00:00
parent 669b0b1521
commit 5c25a92011
1 changed files with 8 additions and 6 deletions
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14
llvm/lib/CodeGen/DwarfEHPrepare.cpp
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@ -93,7 +93,8 @@ namespace {
/// with the eh.exception call. This recursively looks past instructions
/// which don't change the EH pointer value, like casts or PHI nodes.
bool FindSelectorAndURoR(Instruction *Inst, bool &URoRInvoke,
SmallPtrSet<IntrinsicInst*, 8> &SelCalls);
SmallPtrSet<IntrinsicInst*, 8> &SelCalls,
SmallPtrSet<PHINode*, 32> &SeenPHIs);
public:
static char ID; // Pass identification, replacement for typeid.
@ -199,8 +200,8 @@ bool DwarfEHPrepare::CleanupSelectors(SmallPtrSet<IntrinsicInst*, 32> &Sels) {
/// change the EH pointer value, like casts or PHI nodes.
bool
DwarfEHPrepare::FindSelectorAndURoR(Instruction *Inst, bool &URoRInvoke,
SmallPtrSet<IntrinsicInst*, 8> &SelCalls) {
SmallPtrSet<PHINode*, 32> SeenPHIs;
SmallPtrSet<IntrinsicInst*, 8> &SelCalls,
SmallPtrSet<PHINode*, 32> &SeenPHIs) {
bool Changed = false;
for (Value::use_iterator
@ -215,11 +216,11 @@ DwarfEHPrepare::FindSelectorAndURoR(Instruction *Inst, bool &URoRInvoke,
if (Invoke->getCalledFunction() == URoR)
URoRInvoke = true;
} else if (CastInst *CI = dyn_cast<CastInst>(II)) {
Changed |= FindSelectorAndURoR(CI, URoRInvoke, SelCalls);
Changed |= FindSelectorAndURoR(CI, URoRInvoke, SelCalls, SeenPHIs);
} else if (PHINode *PN = dyn_cast<PHINode>(II)) {
if (SeenPHIs.insert(PN))
// Don't process a PHI node more than once.
Changed |= FindSelectorAndURoR(PN, URoRInvoke, SelCalls);
Changed |= FindSelectorAndURoR(PN, URoRInvoke, SelCalls, SeenPHIs);
}
}
@ -294,7 +295,8 @@ bool DwarfEHPrepare::HandleURoRInvokes() {
bool URoRInvoke = false;
SmallPtrSet<IntrinsicInst*, 8> SelCalls;
Changed |= FindSelectorAndURoR(EHPtr, URoRInvoke, SelCalls);
SmallPtrSet<PHINode*, 32> SeenPHIs;
Changed |= FindSelectorAndURoR(EHPtr, URoRInvoke, SelCalls, SeenPHIs);
if (URoRInvoke) {
// This EH pointer is being used by an invoke of an URoR instruction and