Eliminate the static constructors and locks from DynamicLibrary.cpp.

This fixes PR4512 and eliminating static ctors is always good.  Losing
thread safety is unfortunate, but the code is just incredibly poorly
designed.

If someone is interested, the "right" solution is to split
DynamicLibrary.cpp into two separate pieces: a stateless piece in
libsystem, and a simple support file in libsupport that has the
"state" (e.g.  AddSymbol) in managed static objects.

Doing this would both fix memory leaks we already have, as well as make
the code thread safe again.  it would also make sense to move all the
unix specific code in System/DynamicLibrary.cpp into 
System/Unix/DynamicLibrary.inc.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@74927 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 15 insertions, 0 deletions

diff --git a/include/llvm/System/DynamicLibrary.h b/include/llvm/System/DynamicLibrary.h
index f04734a..ac58407 100644
--- a/include/llvm/System/DynamicLibrary.h
+++ b/include/llvm/System/DynamicLibrary.h
@@ -36,6 +36,9 @@ namespace sys {
     /// and will only be unloaded when the program terminates.  This returns
     /// false on success or returns true and fills in *ErrMsg on failure.
     /// @brief Open a dynamic library permanently.
+    ///
+    /// NOTE: This function is not thread safe.
+    ///
     static bool LoadLibraryPermanently(const char *filename,
                                        std::string *ErrMsg = 0);
 
@@ -46,9 +49,15 @@ namespace sys {
     /// as ephemerally loaded libraries (constructors).
     /// @throws std::string on error.
     /// @brief Search through libraries for address of a symbol
+    ///
+    /// NOTE: This function is not thread safe.
+    ///
     static void *SearchForAddressOfSymbol(const char *symbolName);
 
     /// @brief Convenience function for C++ophiles.
+    ///
+    /// NOTE: This function is not thread safe.
+    ///
     static void *SearchForAddressOfSymbol(const std::string &symbolName) {
       return SearchForAddressOfSymbol(symbolName.c_str());
     }
@@ -57,9 +66,15 @@ namespace sys {
     /// value \p symbolValue.  These symbols are searched before any
     /// libraries.
     /// @brief Add searchable symbol/value pair.
+    ///
+    /// NOTE: This function is not thread safe.
+    ///
     static void AddSymbol(const char *symbolName, void *symbolValue);
 
     /// @brief Convenience function for C++ophiles.
+    ///
+    /// NOTE: This function is not thread safe.
+    ///
     static void AddSymbol(const std::string &symbolName, void *symbolValue) {
       AddSymbol(symbolName.c_str(), symbolValue);
     }