[PM] Teach SCEV to invalidate itself when its dependencies become

invalid.

This fixes use-after-free bugs that will arise with any interesting use
of SCEV.

I've added a dedicated test that works diligently to trigger these kinds
of bugs in the new pass manager and also checks for them explicitly as
well as triggering ASan failures when things go squirly.

llvm-svn: 291426

1 files changed, 12 insertions, 0 deletions

diff --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp
index 5e566bcdaff..44f1a6dde0d 100644
--- a/llvm/lib/Analysis/ScalarEvolution.cpp
+++ b/llvm/lib/Analysis/ScalarEvolution.cpp
@@ -10012,6 +10012,18 @@ void ScalarEvolution::verify() const {
   // TODO: Verify more things.
 }
 
+bool ScalarEvolution::invalidate(
+    Function &F, const PreservedAnalyses &PA,
+    FunctionAnalysisManager::Invalidator &Inv) {
+  // Invalidate the ScalarEvolution object whenever it isn't preserved or one
+  // of its dependencies is invalidated.
+  auto PAC = PA.getChecker<ScalarEvolutionAnalysis>();
+  return !(PAC.preserved() || PAC.preservedSet<AllAnalysesOn<Function>>()) ||
+         Inv.invalidate<AssumptionAnalysis>(F, PA) ||
+         Inv.invalidate<DominatorTreeAnalysis>(F, PA) ||
+         Inv.invalidate<LoopAnalysis>(F, PA);
+}
+
 AnalysisKey ScalarEvolutionAnalysis::Key;
 
 ScalarEvolution ScalarEvolutionAnalysis::run(Function &F,