Fix a PassManager pointer use-after-free bug.

[oota-llvm.git] / lib / VMCore / PassManager.cpp

diff --git a/lib/VMCore/PassManager.cpp b/lib/VMCore/PassManager.cpp
index 8362034fcf2d5af9f3da40a74f702ca9fd12ef47..3a8a9e25e3cccea3ab185b107431b3082e08709f 100644 (file)
--- a/lib/VMCore/PassManager.cpp
+++ b/lib/VMCore/PassManager.cpp
@@ -1654,6 +1654,18 @@ void MPPassManager::addLowerLevelRequiredPass(Pass *P, Pass *RequiredPass) {
 
     OnTheFlyManagers[P] = FPP;
   }
+
+  // If RequiredPass is an analysis pass and it is available then do not
+  // generate the analysis again. Stale analysis info should not be
+  // available at this point.
+  const PassInfo *PI =
+    PassRegistry::getPassRegistry()->getPassInfo(RequiredPass->getPassID());
+  if (PI && PI->isAnalysis() && 
+      FPP->getTopLevelManager()->findAnalysisPass(RequiredPass->getPassID())) {
+    delete RequiredPass;
+    return;
+  }
+
   FPP->add(RequiredPass);
 
   // Register P as the last user of RequiredPass.