[libcxx-commits] [libcxx] 6c5b0d6 - [libcxx] Base MSVC autolinking on _LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS

[Martin Storsjö via libcxx-commits]

Author: Martin Storsjö
Date: 2021-04-19T22:42:33+03:00
New Revision: 6c5b0d6beaaa634efce700e0c9cbd098e1c2e8a3

URL: https://github.com/llvm/llvm-project/commit/6c5b0d6beaaa634efce700e0c9cbd098e1c2e8a3
DIFF: https://github.com/llvm/llvm-project/commit/6c5b0d6beaaa634efce700e0c9cbd098e1c2e8a3.diff

LOG: [libcxx] Base MSVC autolinking on _LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS

Previously the decision of which library to try to autolink was
based on _DLL, however the _DLL define (which is set by the compiler)
is tied to whether using a dynamically linked CRT or not, and the choice
of dynamic or static CRT is entirely orthogonal to whether libc++ is
linked dynamically or statically.

If _LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS isn't defined, then all
declarations are decorated with dllimport, and there's no doubt that
the DLL version of the library is what must be linked.

_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS is defined if building with
LIBCXX_ENABLE_SHARED disabled, and thus the static library is what
should be linked.

If defining _LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS manually but wanting
to link against the DLL version of the library, that's not a canonical
configuration, and then it's probably reasonable to manually define
_LIBCPP_NO_AUTO_LINK too, and manually link against the desired
library.

This fixes, among other issues, running tests for the library if
built with LIBCXX_ENABLE_STATIC disabled.

Differential Revision: https://reviews.llvm.org/D100539

Added: 
    

Modified: 
    libcxx/include/__config

Removed: 
    


################################################################################
diff  --git a/libcxx/include/__config b/libcxx/include/__config
index ebef56833cbe..04dc90e67c48 100644
--- a/libcxx/include/__config
+++ b/libcxx/include/__config
@@ -1413,7 +1413,7 @@ extern "C" _LIBCPP_FUNC_VIS void __sanitizer_annotate_contiguous_container(
 
 #ifndef _LIBCPP_NO_AUTO_LINK
 #  if defined(_LIBCPP_ABI_MICROSOFT) && !defined(_LIBCPP_BUILDING_LIBRARY)
-#    if defined(_DLL)
+#    if !defined(_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS)
 #      pragma comment(lib, "c++.lib")
 #    else
 #      pragma comment(lib, "libc++.lib")