aboutsummaryrefslogtreecommitdiffstats
path: root/lib/VMCore
diff options
context:
space:
mode:
authorOwen Anderson <resistor@mac.com>2009-06-17 22:53:57 +0000
committerOwen Anderson <resistor@mac.com>2009-06-17 22:53:57 +0000
commita23d2c126298b5193be46c7d4a1d079a9109ffaf (patch)
tree081a7c96cef91066a3f7630c6b6e9c583e9cf09f /lib/VMCore
parentb983d67465a939c43173e381f9063d9d9245f45b (diff)
downloadexternal_llvm-a23d2c126298b5193be46c7d4a1d079a9109ffaf.zip
external_llvm-a23d2c126298b5193be46c7d4a1d079a9109ffaf.tar.gz
external_llvm-a23d2c126298b5193be46c7d4a1d079a9109ffaf.tar.bz2
Use double-checked locking for this lazy initialization.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73653 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/VMCore')
-rw-r--r--lib/VMCore/Type.cpp23
1 files changed, 21 insertions, 2 deletions
diff --git a/lib/VMCore/Type.cpp b/lib/VMCore/Type.cpp
index b815eec..0add0af 100644
--- a/lib/VMCore/Type.cpp
+++ b/lib/VMCore/Type.cpp
@@ -453,8 +453,27 @@ void DerivedType::dropAllTypeUses() {
if (NumContainedTys != 0) {
// The type must stay abstract. To do this, we insert a pointer to a type
// that will never get resolved, thus will always be abstract.
- static Type *AlwaysOpaqueTy = OpaqueType::get();
- static PATypeHolder Holder(AlwaysOpaqueTy);
+ static Type *AlwaysOpaqueTy = 0;
+ static PATypeHolder* Holder = 0;
+ if (!AlwaysOpaqueTy) {
+ if (llvm_is_multithreaded()) {
+ llvm_acquire_global_lock();
+
+ if (!AlwaysOpaqueTy) {
+ Type *tmp = OpaqueType::get();
+ PATypeHolder* tmp2 = new PATypeHolder(AlwaysOpaqueTy);
+ sys::MemoryFence();
+ AlwaysOpaqueTy = tmp;
+ Holder = tmp2;
+ }
+
+ llvm_release_global_lock();
+ } else {
+ AlwaysOpaqueTy = OpaqueType::get();
+ Holder = new PATypeHolder(AlwaysOpaqueTy);
+ }
+ }
+
ContainedTys[0] = AlwaysOpaqueTy;
// Change the rest of the types to be Int32Ty's. It doesn't matter what we