bool AAResults::invalidate(Function &F, const PreservedAnalyses &PA,
FunctionAnalysisManager::Invalidator &Inv) {
// AAResults preserves the AAManager by default, due to the stateless nature
// of AliasAnalysis. There is no need to check whether it has been preserved
// explicitly. Check if any module dependency was invalidated and caused the
// AAManager to be invalidated. Invalidate ourselves in that case.
auto PAC = PA.getChecker<AAManager>();
if (!PAC.preservedWhenStateless())
return true;
// Check if any of the function dependencies were invalidated, and invalidate
// ourselves in that case.
for (AnalysisKey *ID : AADeps)
if (Inv.invalidate(ID, F, PA))
return true;
// Everything we depend on is still fine, so are we. Nothing to invalidate.
return false;
}
bool LoopAnalysisManagerFunctionProxy::Result::invalidate(
Function &F, const PreservedAnalyses &PA,
FunctionAnalysisManager::Invalidator &Inv) {
// First compute the sequence of IR units covered by this proxy. We will want
// to visit this in postorder, but because this is a tree structure we can do
// this by building a preorder sequence and walking it in reverse.
SmallVector<Loop *, 4> PreOrderLoops, PreOrderWorklist;
// Note that we want to walk the roots in reverse order because we will end
// up reversing the preorder sequence. However, it happens that the loop nest
// roots are in reverse order within the LoopInfo object. So we just walk
// forward here.
// FIXME: If we change the order of LoopInfo we will want to add a reverse
// here.
for (Loop *RootL : *LI) {
assert(PreOrderWorklist.empty() &&
"Must start with an empty preorder walk worklist.");
PreOrderWorklist.push_back(RootL);
do {
Loop *L = PreOrderWorklist.pop_back_val();
PreOrderWorklist.append(L->begin(), L->end());
PreOrderLoops.push_back(L);
} while (!PreOrderWorklist.empty());
}
// If this proxy or the loop info is going to be invalidated, we also need
// to clear all the keys coming from that analysis. We also completely blow
// away the loop analyses if any of the standard analyses provided by the
// loop pass manager go away so that loop analyses can freely use these
// without worrying about declaring dependencies on them etc.
// FIXME: It isn't clear if this is the right tradeoff. We could instead make
// loop analyses declare any dependencies on these and use the more general
// invalidation logic below to act on that.
auto PAC = PA.getChecker<LoopAnalysisManagerFunctionProxy>();
if (!(PAC.preserved() || PAC.preservedSet<AllAnalysesOn<Function>>()) ||
Inv.invalidate<AAManager>(F, PA) ||
Inv.invalidate<AssumptionAnalysis>(F, PA) ||
Inv.invalidate<DominatorTreeAnalysis>(F, PA) ||
Inv.invalidate<LoopAnalysis>(F, PA) ||
Inv.invalidate<ScalarEvolutionAnalysis>(F, PA)) {
// Note that the LoopInfo may be stale at this point, however the loop
// objects themselves remain the only viable keys that could be in the
// analysis manager's cache. So we just walk the keys and forcibly clear
// those results. Note that the order doesn't matter here as this will just
// directly destroy the results without calling methods on them.
for (Loop *L : PreOrderLoops)
InnerAM->clear(*L);
// We also need to null out the inner AM so that when the object gets
// destroyed as invalid we don't try to clear the inner AM again. At that
// point we won't be able to reliably walk the loops for this function and
// only clear results associated with those loops the way we do here.
// FIXME: Making InnerAM null at this point isn't very nice. Most analyses
// try to remain valid during invalidation. Maybe we should add an
// `IsClean` flag?
InnerAM = nullptr;
// Now return true to indicate this *is* invalid and a fresh proxy result
// needs to be built. This is especially important given the null InnerAM.
return true;
}
// Directly check if the relevant set is preserved so we can short circuit
// invalidating loops.
bool AreLoopAnalysesPreserved =
PA.allAnalysesInSetPreserved<AllAnalysesOn<Loop>>();
// Since we have a valid LoopInfo we can actually leave the cached results in
// the analysis manager associated with the Loop keys, but we need to
// propagate any necessary invalidation logic into them. We'd like to
// invalidate things in roughly the same order as they were put into the
// cache and so we walk the preorder list in reverse to form a valid
// postorder.
for (Loop *L : reverse(PreOrderLoops)) {
Optional<PreservedAnalyses> InnerPA;
// Check to see whether the preserved set needs to be adjusted based on
// function-level analysis invalidation triggering deferred invalidation
// for this loop.
if (auto *OuterProxy =
InnerAM->getCachedResult<FunctionAnalysisManagerLoopProxy>(*L))
for (const auto &OuterInvalidationPair :
OuterProxy->getOuterInvalidations()) {
AnalysisKey *OuterAnalysisID = OuterInvalidationPair.first;
const auto &InnerAnalysisIDs = OuterInvalidationPair.second;
if (Inv.invalidate(OuterAnalysisID, F, PA)) {
if (!InnerPA)
InnerPA = PA;
for (AnalysisKey *InnerAnalysisID : InnerAnalysisIDs)
InnerPA->abandon(InnerAnalysisID);
}
}
// Check if we needed a custom PA set. If so we'll need to run the inner
// invalidation.
if (InnerPA) {
InnerAM->invalidate(*L, *InnerPA);
continue;
}
// Otherwise we only need to do invalidation if the original PA set didn't
// preserve all Loop analyses.
if (!AreLoopAnalysesPreserved)
InnerAM->invalidate(*L, PA);
}
// Return false to indicate that this result is still a valid proxy.
return false;
}