-#ifndef NDEBUG
-static const Function *getParent(const Value *V) {
- if (const Instruction *inst = dyn_cast<Instruction>(V))
- return inst->getParent()->getParent();
-
- if (const Argument *arg = dyn_cast<Argument>(V))
- return arg->getParent();
-
- return nullptr;
-}
-
-static bool notDifferentParent(const Value *O1, const Value *O2) {
-
- const Function *F1 = getParent(O1);
- const Function *F2 = getParent(O2);
-
- return !F1 || !F2 || F1 == F2;
-}
-#endif
-
-namespace {
- /// BasicAliasAnalysis - This is the primary alias analysis implementation.
- struct BasicAliasAnalysis : public ImmutablePass, public AliasAnalysis {
- static char ID; // Class identification, replacement for typeinfo
- BasicAliasAnalysis() : ImmutablePass(ID) {
- initializeBasicAliasAnalysisPass(*PassRegistry::getPassRegistry());
- }
-
- void initializePass() override {
- InitializeAliasAnalysis(this);
- }
-
- void getAnalysisUsage(AnalysisUsage &AU) const override {
- AU.addRequired<AliasAnalysis>();
- AU.addRequired<TargetLibraryInfo>();
- }
-
- AliasResult alias(const Location &LocA, const Location &LocB) override {
- assert(AliasCache.empty() && "AliasCache must be cleared after use!");
- assert(notDifferentParent(LocA.Ptr, LocB.Ptr) &&
- "BasicAliasAnalysis doesn't support interprocedural queries.");
- AliasResult Alias = aliasCheck(LocA.Ptr, LocA.Size, LocA.TBAATag,
- LocB.Ptr, LocB.Size, LocB.TBAATag);
- // AliasCache rarely has more than 1 or 2 elements, always use
- // shrink_and_clear so it quickly returns to the inline capacity of the
- // SmallDenseMap if it ever grows larger.
- // FIXME: This should really be shrink_to_inline_capacity_and_clear().
- AliasCache.shrink_and_clear();
- VisitedPhiBBs.clear();
- return Alias;
- }
-
- ModRefResult getModRefInfo(ImmutableCallSite CS,
- const Location &Loc) override;
-
- ModRefResult getModRefInfo(ImmutableCallSite CS1,
- ImmutableCallSite CS2) override {
- // The AliasAnalysis base class has some smarts, lets use them.
- return AliasAnalysis::getModRefInfo(CS1, CS2);
- }
-
- /// pointsToConstantMemory - Chase pointers until we find a (constant
- /// global) or not.
- bool pointsToConstantMemory(const Location &Loc, bool OrLocal) override;
-
- /// getModRefBehavior - Return the behavior when calling the given
- /// call site.
- ModRefBehavior getModRefBehavior(ImmutableCallSite CS) override;
-
- /// getModRefBehavior - Return the behavior when calling the given function.
- /// For use when the call site is not known.
- ModRefBehavior getModRefBehavior(const Function *F) override;
-
- /// getAdjustedAnalysisPointer - This method is used when a pass implements
- /// an analysis interface through multiple inheritance. If needed, it
- /// should override this to adjust the this pointer as needed for the
- /// specified pass info.
- void *getAdjustedAnalysisPointer(const void *ID) override {
- if (ID == &AliasAnalysis::ID)
- return (AliasAnalysis*)this;
- return this;
- }
-
- private:
- // AliasCache - Track alias queries to guard against recursion.
- typedef std::pair<Location, Location> LocPair;
- typedef SmallDenseMap<LocPair, AliasResult, 8> AliasCacheTy;
- AliasCacheTy AliasCache;
-
- /// \brief Track phi nodes we have visited. When interpret "Value" pointer
- /// equality as value equality we need to make sure that the "Value" is not
- /// part of a cycle. Otherwise, two uses could come from different
- /// "iterations" of a cycle and see different values for the same "Value"
- /// pointer.
- /// The following example shows the problem:
- /// %p = phi(%alloca1, %addr2)
- /// %l = load %ptr
- /// %addr1 = gep, %alloca2, 0, %l
- /// %addr2 = gep %alloca2, 0, (%l + 1)
- /// alias(%p, %addr1) -> MayAlias !
- /// store %l, ...
- SmallPtrSet<const BasicBlock*, 8> VisitedPhiBBs;
-
- // Visited - Track instructions visited by pointsToConstantMemory.
- SmallPtrSet<const Value*, 16> Visited;
-
- /// \brief Check whether two Values can be considered equivalent.
- ///
- /// In addition to pointer equivalence of \p V1 and \p V2 this checks
- /// whether they can not be part of a cycle in the value graph by looking at
- /// all visited phi nodes an making sure that the phis cannot reach the
- /// value. We have to do this because we are looking through phi nodes (That
- /// is we say noalias(V, phi(VA, VB)) if noalias(V, VA) and noalias(V, VB).
- bool isValueEqualInPotentialCycles(const Value *V1, const Value *V2);
-
- /// \brief Dest and Src are the variable indices from two decomposed
- /// GetElementPtr instructions GEP1 and GEP2 which have common base
- /// pointers. Subtract the GEP2 indices from GEP1 to find the symbolic
- /// difference between the two pointers.
- void GetIndexDifference(SmallVectorImpl<VariableGEPIndex> &Dest,
- const SmallVectorImpl<VariableGEPIndex> &Src);
-
- // aliasGEP - Provide a bunch of ad-hoc rules to disambiguate a GEP
- // instruction against another.
- AliasResult aliasGEP(const GEPOperator *V1, uint64_t V1Size,
- const MDNode *V1TBAAInfo,
- const Value *V2, uint64_t V2Size,
- const MDNode *V2TBAAInfo,
- const Value *UnderlyingV1, const Value *UnderlyingV2);
-
- // aliasPHI - Provide a bunch of ad-hoc rules to disambiguate a PHI
- // instruction against another.
- AliasResult aliasPHI(const PHINode *PN, uint64_t PNSize,
- const MDNode *PNTBAAInfo,
- const Value *V2, uint64_t V2Size,
- const MDNode *V2TBAAInfo);
-
- /// aliasSelect - Disambiguate a Select instruction against another value.
- AliasResult aliasSelect(const SelectInst *SI, uint64_t SISize,
- const MDNode *SITBAAInfo,
- const Value *V2, uint64_t V2Size,
- const MDNode *V2TBAAInfo);
-
- AliasResult aliasCheck(const Value *V1, uint64_t V1Size,
- const MDNode *V1TBAATag,
- const Value *V2, uint64_t V2Size,
- const MDNode *V2TBAATag);
- };
-} // End of anonymous namespace
-
-// Register this pass...