On Fri, 14 Nov 2025 11:25:05 GMT, Matthias Baesken <[email protected]> wrote:

> The dead_strip linker option on macOS removes functions and data that are 
> unreachable by the entry point or exported symbols.
> Setting it can reduce the size of some binaries we generate quite a lot, for 
> example (product build, Xcode 15 is used) :
> (before -> after setting the option)
> 
> 1.4M -> 1.1M images/jdk/lib/libfontmanager.dylib
> 264K -> 248K images/jdk/lib/libjavajpeg.dylib
> 152K -> 132K images/jdk/lib/libjli.dylib
> 388K -> 296K images/jdk/lib/liblcms.dylib
> 164K -> 128K images/jdk/lib/libzip.dylib
> 
> 
> and libjvm :
> 
> 20M -> 18M images/jdk/lib/server/libjvm.dylib
> 146M -> 137M images/jdk/lib/server/libjvm.dylib.dSYM

The following is how you declare a reference to the vtable:

extern "C" void* _ZTV8Metadata[];

If you then reference _ZTV8Metadata from somewhere in a way that does not get 
dead stripped, that seems to fix the problem. The latter part is definitely 
very hacky. It would be nice to get a pragma working to keep the symbol from 
being deadstripped.

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PR Comment: https://git.openjdk.org/jdk/pull/28319#issuecomment-3553874175

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