[PATCH v5 0/43] MR6623: Draft: include/winnt.h: Add support for thread safety annotation attributes.

[Vibhav Pant (＠vibhavp)]

This MR introduces support for [thread safety annotations,](https://clang.llvm.org/docs/ThreadSafetyAnalysis.html#conditional-locks) currently supported by Clang. The feature is similar to `__WINE_MALLOC` attributes, allowing functions, data members and global variables to be optionally annotated with synchronization details.

As a proof of concept, I have annotated `RTL_CRITICAL_SECTION` and `dlls/ntdll`.

Because the feature was designed as a C++ extension first, a bit of stubbing is required to annotate struct fields about what lock they are guarded by. The macros `WINE_DECLARE_LOCK_FIELD_STUB` and `WINE_DEFINE_LOCK_FIELD_STUB` take care of that. For instance, in `dlls/ntdll/threadpool.c`:

```c
WINE_DECLARE_LOCK_FIELD_STUB(threadpool_group, CRITICAL_SECTION, cs);
struct threadpool_group
{
    LONG                    refcount;
    BOOL                    shutdown;
    CRITICAL_SECTION        cs;
    /* list of group members, locked via .cs */
    struct list             members __WINE_FIELD_GUARDED_BY(threadpool_group, cs);
};
WINE_DEFINE_LOCK_FIELD_STUB(threadpool_group, CRITICAL_SECTION, cs);
```

Clang will therefore warn if `members` is accessed without holding `cs`.

Note that the analyzer does not support conditional locking. For that reason, functions that hold and release a lock conditionally have been marked with `__WINE_NO_THREAD_SAFETY_ANALYSIS` to pre-empt false positives from Clang.

--
  v5: dlls/amstream/tests: Disable thread safety analysis for testfilter_wait_state.
 
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https://gitlab.winehq.org/wine/wine/-/merge_requests/6623