On Thu, 13 Apr 2023 20:04:15 GMT, Jiangli Zhou <jian...@openjdk.org> wrote:
>> src/jdk.management/share/native/libmanagement_ext/management_ext.c line 36: >> >>> 34: const JmmInterface* jmm_interface_management_ext = NULL; >>> 35: static JavaVM* jvm = NULL; >>> 36: jint jmm_version_management_ext = 0; >> >> Is there not a way to stop these from being exported from the library, as I >> assume they are not actually intended for external use. ?? > >> Is there not a way to stop these from being exported from the library, as I >> assume they are not actually intended for external use. ?? > > Good question. > > We could make those as weak symbols as long as there is no concern about > portability. In our current prototype on JDK 11, we use weak symbol to help > detect if we are dealing with a statically linked binary at runtime then > handle some of the cases conditionally (dynamic vs. static). Around the end > of last year, I became aware that there could be issues in some cases on > macos with weak symbols (e.g. without '-undefined dynamic_lookup'). I'm > planning to look into alternatives (besides using weak symbol) when porting > the support to the latest OpenJDK code base. > > Another approach is using 'objcopy' > (https://web.mit.edu/gnu/doc/html/binutils_4.html) to localize the > problematic symbols in the object file. It was suggested by our C++ > colleague. We used that to hide symbols in libfreetype and libharfbuzz (there > were problems when user code requires its own specific statically linked > libfreetype and libharfbuzz due to versioning difference). So we first > partially link all .o for the particular native library (in JDK) to form one > .o file, then run 'objcopy' to localize the symbols. That hides the affected > symbols during final link time. We had to do that since we don't control > libfreetype and libharfbuzz. It worked for our specific case (for linux). > It's probably not a general solution. > > The direct renaming in this case seems to be more strait forward. Any > thoughts? Forgot to mention that using 'static' effectively resolves the symbol issue when feasible, like the 'jvm' variable case. That doesn't work for the 'jmm_interface' and 'jmm_version' ... ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/13451#discussion_r1166010486
