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Add a depth limit to avoid runaway recursion. 

llvm-svn: 148419
This commit is contained in:
Dan Gohman 2012-01-18 21:24:45 +00:00
parent 8715c517d5
commit 8f12faeb14
1 changed files with 7 additions and 3 deletions
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10
llvm/lib/Transforms/Scalar/ObjCARC.cpp
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@ -895,7 +895,7 @@ namespace {
virtual void getAnalysisUsage(AnalysisUsage &AU) const; virtual void getAnalysisUsage(AnalysisUsage &AU) const;
virtual bool runOnModule(Module &M); virtual bool runOnModule(Module &M);
bool MayAutorelease(CallSite CS); bool MayAutorelease(CallSite CS, unsigned Depth = 0);
bool OptimizeBB(BasicBlock *BB); bool OptimizeBB(BasicBlock *BB);
public: public:
@ -922,7 +922,7 @@ void ObjCARCAPElim::getAnalysisUsage(AnalysisUsage &AU) const {
/// MayAutorelease - Interprocedurally determine if calls made by the /// MayAutorelease - Interprocedurally determine if calls made by the
/// given call site can possibly produce autoreleases. /// given call site can possibly produce autoreleases.
bool ObjCARCAPElim::MayAutorelease(CallSite CS) { bool ObjCARCAPElim::MayAutorelease(CallSite CS, unsigned Depth) {
if (Function *Callee = CS.getCalledFunction()) { if (Function *Callee = CS.getCalledFunction()) {
if (Callee->isDeclaration() || Callee->mayBeOverridden()) if (Callee->isDeclaration() || Callee->mayBeOverridden())
return true; return true;
@ -931,7 +931,11 @@ bool ObjCARCAPElim::MayAutorelease(CallSite CS) {
BasicBlock *BB = I; BasicBlock *BB = I;
for (BasicBlock::iterator J = BB->begin(), F = BB->end(); J != F; ++J) for (BasicBlock::iterator J = BB->begin(), F = BB->end(); J != F; ++J)
if (CallSite JCS = CallSite(J)) if (CallSite JCS = CallSite(J))
if (!JCS.onlyReadsMemory() && MayAutorelease(JCS)) // This recursion depth limit is arbitrary. It's just great
// enough to cover known interesting testcases.
if (Depth < 3 &&
!JCS.onlyReadsMemory() &&
MayAutorelease(JCS, Depth + 1))
return true; return true;
} }
return false; return false;