diff options
Diffstat (limited to 'lib/Analysis/MemoryDependenceAnalysis.cpp')
| -rw-r--r-- | lib/Analysis/MemoryDependenceAnalysis.cpp | 14 |
1 files changed, 11 insertions, 3 deletions
diff --git a/lib/Analysis/MemoryDependenceAnalysis.cpp b/lib/Analysis/MemoryDependenceAnalysis.cpp index 059e57493b..5736c3569d 100644 --- a/lib/Analysis/MemoryDependenceAnalysis.cpp +++ b/lib/Analysis/MemoryDependenceAnalysis.cpp @@ -148,7 +148,7 @@ AliasAnalysis::ModRefResult GetLocation(const Instruction *Inst, return AliasAnalysis::ModRef; } - if (const CallInst *CI = isFreeCall(Inst)) { + if (const CallInst *CI = isFreeCall(Inst, AA->getTargetLibraryInfo())) { // calls to free() deallocate the entire structure Loc = AliasAnalysis::Location(CI->getArgOperand(0)); return AliasAnalysis::Mod; @@ -479,12 +479,20 @@ getPointerDependencyFrom(const AliasAnalysis::Location &MemLoc, bool isLoad, // a subsequent bitcast of the malloc call result. There can be stores to // the malloced memory between the malloc call and its bitcast uses, and we // need to continue scanning until the malloc call. - if (isa<AllocaInst>(Inst) || isNoAliasFn(Inst)) { + const TargetLibraryInfo *TLI = AA->getTargetLibraryInfo(); + if (isa<AllocaInst>(Inst) || isNoAliasFn(Inst, TLI)) { const Value *AccessPtr = GetUnderlyingObject(MemLoc.Ptr, TD); if (AccessPtr == Inst || AA->isMustAlias(Inst, AccessPtr)) return MemDepResult::getDef(Inst); - continue; + // Be conservative if the accessed pointer may alias the allocation. + if (AA->alias(Inst, AccessPtr) != AliasAnalysis::NoAlias) + return MemDepResult::getClobber(Inst); + // If the allocation is not aliased and does not read memory (like + // strdup), it is safe to ignore. + if (isa<AllocaInst>(Inst) || + isMallocLikeFn(Inst, TLI) || isCallocLikeFn(Inst, TLI)) + continue; } // See if this instruction (e.g. a call or vaarg) mod/ref's the pointer. |