From 4dd1ce8e56b4d391c8d85c90bcc0d3ae68a6134e Mon Sep 17 00:00:00 2001
From: Frederich Munch <marsupial@users.noreply.github.com>
Date: Thu, 2 Feb 2017 12:44:32 -0500
Subject: [PATCH] Fix for Interpreter hanging on to states that can refer to a
 deleted llvm::Module.

---
 .../cling/Interpreter/ClangInternalState.h    |  4 +++
 lib/Interpreter/Interpreter.cpp               | 31 +++++++++++++++++--
 test/ErrorRecovery/StoredState.C              | 19 ++++++++++++
 3 files changed, 52 insertions(+), 2 deletions(-)
 create mode 100644 test/ErrorRecovery/StoredState.C

diff --git a/include/cling/Interpreter/ClangInternalState.h b/include/cling/Interpreter/ClangInternalState.h
index c6159628..e9972ca8 100644
--- a/include/cling/Interpreter/ClangInternalState.h
+++ b/include/cling/Interpreter/ClangInternalState.h
@@ -81,6 +81,10 @@ namespace cling {
                           const char* type = nullptr, bool verbose = false,
                const llvm::SmallVectorImpl<llvm::StringRef>* ignores = 0) const;
 
+    ///\brief Return the llvm::Module this state is bound too.
+    ///
+    const llvm::Module* getModule() const { return m_Module; }
+
     static void printLookupTables(llvm::raw_ostream& Out, const clang::ASTContext& C);
     static void printIncludedFiles(llvm::raw_ostream& Out,
                                    const clang::SourceManager& SM);
diff --git a/lib/Interpreter/Interpreter.cpp b/lib/Interpreter/Interpreter.cpp
index f89d19e2..6e9fdece 100644
--- a/lib/Interpreter/Interpreter.cpp
+++ b/lib/Interpreter/Interpreter.cpp
@@ -314,10 +314,14 @@ namespace cling {
   }
 
   Interpreter::~Interpreter() {
-    if (m_Executor)
-      m_Executor->shuttingDown();
+    // Do this first so m_StoredStates will be ignored if Interpreter::unload
+    // is called later on.
     for (size_t i = 0, e = m_StoredStates.size(); i != e; ++i)
       delete m_StoredStates[i];
+    m_StoredStates.clear();
+
+    if (m_Executor)
+      m_Executor->shuttingDown();
 
     if (CompilerInstance* CI = getCIOrNull())
       getCI()->getDiagnostics().getClient()->EndSourceFile();
@@ -1177,6 +1181,29 @@ namespace cling {
   }
 
   void Interpreter::unload(Transaction& T) {
+    // Clear any stored states that reference the llvm::Module.
+    // Do it first in case
+    if (!m_StoredStates.empty()) {
+      const llvm::Module* const module = T.getModule();
+      std::vector<unsigned> badStates;
+      for (unsigned i = 0, N = m_StoredStates.size(); i < N; ++i) {
+        if (m_StoredStates[i]->getModule() == module) {
+          badStates.push_back(i);
+          if (m_Opts.Verbose()) {
+            cling::errs() << "Unloading Transaction forced state '"
+                          << m_StoredStates[i]->getName()
+                          << "' to be destroyed\n";
+          }
+        }
+      }
+      // Pop off the back so as not to recompute index.
+      // Should the user be warned in verbose mode?
+      for (std::vector<unsigned>::reverse_iterator it = badStates.rbegin(),
+           e = badStates.rend(); it != e; ++it) {
+        m_StoredStates.erase(m_StoredStates.begin()+(*it));
+      }
+    }
+
     if (InterpreterCallbacks* callbacks = getCallbacks())
       callbacks->TransactionUnloaded(T);
     if (m_Executor) { // we also might be in fsyntax-only mode.
diff --git a/test/ErrorRecovery/StoredState.C b/test/ErrorRecovery/StoredState.C
new file mode 100644
index 00000000..2ad0f2bd
--- /dev/null
+++ b/test/ErrorRecovery/StoredState.C
@@ -0,0 +1,19 @@
+//------------------------------------------------------------------------------
+// CLING - the C++ LLVM-based InterpreterG :)
+//
+// This file is dual-licensed: you can choose to license it under the University
+// of Illinois Open Source License or the GNU Lesser General Public License. See
+// LICENSE.TXT for details.
+//------------------------------------------------------------------------------
+
+// RUN: cat %s | %cling -v -Xclang -verify 2>&1 | FileCheck %s
+
+int i = 0;
+.storeState "A"
+
+.undo
+// CHECK: Unloading Transaction forced state 'A' to be destroyed
+
+// expected-no-diagnostics
+
+.q