From 7390550dfe406b7e513995ccc4e80896dd7fe2bc Mon Sep 17 00:00:00 2001
From: Axel Naumann <Axel.Naumann@cern.ch>
Date: Sun, 23 Mar 2014 21:08:48 +0100
Subject: [PATCH] Add comment explaining (part of) the bootstrap sequencing.

---
 lib/Interpreter/IncrementalParser.cpp | 5 ++++-
 lib/Interpreter/Interpreter.cpp       | 4 +++-
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/lib/Interpreter/IncrementalParser.cpp b/lib/Interpreter/IncrementalParser.cpp
index b17324dc..7c1f6b1c 100644
--- a/lib/Interpreter/IncrementalParser.cpp
+++ b/lib/Interpreter/IncrementalParser.cpp
@@ -98,7 +98,6 @@ namespace cling {
     const std::string& PCHFileName
       = m_CI->getInvocation ().getPreprocessorOpts().ImplicitPCHInclude;
     if (!PCHFileName.empty()) {
-      
       Transaction* CurT = beginTransaction(CO);
       m_CI->createPCHExternalASTSource(PCHFileName,
                                        true /*DisablePCHValidation*/,
@@ -124,8 +123,12 @@ namespace cling {
     if (External)
       External->StartTranslationUnit(m_Consumer);
 
+    // DO NOT commit the transactions here: static initialization in these
+    // transactions requires gCling through local_cxa_atexit(), but that has not
+    // been defined yet!
     if (Transaction* EndedT = endTransaction(CurT))
       result.push_back(EndedT);
+
   }
 
   IncrementalParser::~IncrementalParser() {
diff --git a/lib/Interpreter/Interpreter.cpp b/lib/Interpreter/Interpreter.cpp
index d839c182..bc5c7c18 100644
--- a/lib/Interpreter/Interpreter.cpp
+++ b/lib/Interpreter/Interpreter.cpp
@@ -198,7 +198,9 @@ namespace cling {
     else
       IncludeCRuntime();
 
-   for (llvm::SmallVectorImpl<Transaction*>::const_iterator
+    // Commit the transactions, now that gCling is set up. It is needed for
+    // static initialization in these transactions through local_cxa_atexit().
+    for (llvm::SmallVectorImpl<Transaction*>::const_iterator
            I = IncrParserTransactions.begin(), E = IncrParserTransactions.end();
          I != E; ++I)
       m_IncrParser->commitTransaction(*I);