Windows: Use GetModuleHandleEx instead of LoadLibrary
We were using an anti-pattern of:
- LoadLibrary
- GetProcAddress
- FreeLibrary
This is problematic because of several reasons:
- We are holding on to pointers into a library we just unloaded.
- Calling LoadLibrary results in an increase in the reference count of
the library in question and any libraries that it depends on and
so-on and so-forth. This is none too quick.
Instead, use GetModuleHandleEx with GET_MODULE_HANDLE_EX_FLAG_PIN. This
is done because because we didn't bring the reference for the library
into existence and therefor shouldn't count on it being around later.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192550
91177308-0d34-0410-b5e6-
96231b3b80d8