Free the constants that have no uses in ~LLVMContext.

This fixes leaks from LLVMContext in multithreaded apps.
Since constants are only deleted if they have no uses, it is safe to not delete
a Module on shutdown, as many single-threaded tools do.
Multithreaded apps should however delete the Module before destroying the
Context to ensure that there are no leaks (assuming they use a different context
for each thread).

llvm-svn: 80590

1 files changed, 8 insertions, 0 deletions

diff --git a/llvm/lib/VMCore/ConstantsContext.h b/llvm/lib/VMCore/ConstantsContext.h
index 22aba7e1d35..f4a2cde5d0f 100644
--- a/llvm/lib/VMCore/ConstantsContext.h
+++ b/llvm/lib/VMCore/ConstantsContext.h
@@ -575,6 +575,14 @@ public:
   // to enforce proper synchronization.
   typename MapTy::iterator map_begin() { return Map.begin(); }
   typename MapTy::iterator map_end() { return Map.end(); }
+
+  void freeConstants() {
+    for (typename MapTy::iterator I=Map.begin(), E=Map.end();
+         I != E; ++I) {
+      if (I->second->use_empty())
+        delete I->second;
+    }
+  }
     
   /// InsertOrGetItem - Return an iterator for the specified element.
   /// If the element exists in the map, the returned iterator points to the