Remove the last improper use of getGlobalContext() from LLVM.

This caused a race condition where a thread calls ~LLVMContextImpl which calls
Module::dropAllReferences which calls begin() on an empty ilist that would
create the sentinel, which racily accesses the global context.

This can not be fixed by locking inside createSentinel because the lock would
need to be shared with all users of the global context, including those that
reside outside LLVM's own code.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@137546 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 1 insertions, 18 deletions

diff --git a/lib/VMCore/Module.cpp b/lib/VMCore/Module.cpp
index ee63d696d5..c29029bf6c 100644
--- a/lib/VMCore/Module.cpp
+++ b/lib/VMCore/Module.cpp
@@ -32,25 +32,10 @@ using namespace llvm;
 // Methods to implement the globals and functions lists.
 //
 
-GlobalVariable *ilist_traits<GlobalVariable>::createSentinel() {
-  GlobalVariable *Ret = new GlobalVariable(Type::getInt32Ty(getGlobalContext()),
-                                           false, GlobalValue::ExternalLinkage);
-  // This should not be garbage monitored.
-  LeakDetector::removeGarbageObject(Ret);
-  return Ret;
-}
-GlobalAlias *ilist_traits<GlobalAlias>::createSentinel() {
-  GlobalAlias *Ret = new GlobalAlias(Type::getInt32Ty(getGlobalContext()),
-                                     GlobalValue::ExternalLinkage);
-  // This should not be garbage monitored.
-  LeakDetector::removeGarbageObject(Ret);
-  return Ret;
-}
-
 // Explicit instantiations of SymbolTableListTraits since some of the methods
 // are not in the public header file.
-template class llvm::SymbolTableListTraits<GlobalVariable, Module>;
 template class llvm::SymbolTableListTraits<Function, Module>;
+template class llvm::SymbolTableListTraits<GlobalVariable, Module>;
 template class llvm::SymbolTableListTraits<GlobalAlias, Module>;
 
 //===----------------------------------------------------------------------===//
@@ -552,5 +537,3 @@ namespace {
 void Module::findUsedStructTypes(std::vector<StructType*> &StructTypes) const {
   TypeFinder(StructTypes).run(*this);
 }
-
-