Cleanup: remove workarounds and version checks for unsupported compilers

Match minimum supported versions from the WIKI [0] by raising them to:

- GCC 9.3.1
- CLANG 8.0
- MVCS 2019 (16.9.16 / 1928)

Details:

- Add CMake checks that ensure supported compiler versions early on.
- Previously GCC per-processor version checks served to exclude
  `__clang__`, in some cases this has been replaced by explicitly
  excluding `__clang__`. This was needed as CLANG treated some of these
  flags differently to GCC, causing the build to fail.
- Remove USE_APPLE_OMP_FIX GCC-4.2 OpenMP workaround.
- Remove linking error workaround for old MSVC versions.

[0]: https://wiki.blender.org/wiki/Building_Blender

Reviewed by: brecht, LazyDodo

Ref D16068

1 files changed, 1 insertions, 27 deletions

diff --git a/source/blender/blenlib/intern/threads.cc b/source/blender/blenlib/intern/threads.cc
index 156f2a7b338..f99a27c2475 100644
--- a/source/blender/blenlib/intern/threads.cc
+++ b/source/blender/blenlib/intern/threads.cc
@@ -37,17 +37,6 @@
 
 #include "atomic_ops.h"
 
-#if defined(__APPLE__) && defined(_OPENMP) && (__GNUC__ == 4) && (__GNUC_MINOR__ == 2) && \
-    !defined(__clang__)
-#  define USE_APPLE_OMP_FIX
-#endif
-
-#ifdef USE_APPLE_OMP_FIX
-/* ************** libgomp (Apple gcc 4.2.1) TLS bug workaround *************** */
-extern pthread_key_t gomp_tls_key;
-static void *thread_tls_data;
-#endif
-
 /**
  * Basic Thread Control API
  * ========================
@@ -153,15 +142,7 @@ void BLI_threadpool_init(ListBase *threadbase, void *(*do_thread)(void *), int t
     }
   }
 
-  uint level = atomic_fetch_and_add_u(&thread_levels, 1);
-  if (level == 0) {
-#ifdef USE_APPLE_OMP_FIX
-    /* Workaround for Apple gcc 4.2.1 OMP vs background thread bug,
-     * we copy GOMP thread local storage pointer to setting it again
-     * inside the thread that we start. */
-    thread_tls_data = pthread_getspecific(gomp_tls_key);
-#endif
-  }
+  atomic_fetch_and_add_u(&thread_levels, 1);
 }
 
 int BLI_available_threads(ListBase *threadbase)
@@ -194,13 +175,6 @@ int BLI_threadpool_available_thread_index(ListBase *threadbase)
 static void *tslot_thread_start(void *tslot_p)
 {
   ThreadSlot *tslot = (ThreadSlot *)tslot_p;
-
-#ifdef USE_APPLE_OMP_FIX
-  /* Workaround for Apple gcc 4.2.1 OMP vs background thread bug,
-   * set GOMP thread local storage pointer which was copied beforehand */
-  pthread_setspecific(gomp_tls_key, thread_tls_data);
-#endif
-
   return tslot->do_thread(tslot->callerdata);
 }