We actually use this while linking on Windows, and hence we need to
extract symbols from this file, and not the DLL.
However, we cannot pass it instead of the DLL because it's an optional
output of the compiler. It will not be written out at all if there are
no symbols in the DLL, and we cannot know that at configure time. This
means we cannot describe it as an output of any ninja target, or the
input of any ninja target. We must pass it as an argument without
semantic meaning.
-g is --extern-only and -P is --format=posix. We were missing
--defined-only for some reason, which we pass to `nm` on Linux.
This avoids having to manually filter later.
If we change a symbol size (e.g. array) in a .c file that is a part of
.so, executables that use it are not re-linked resulting in a runtime
error:
"Symbol xyz has different size in shared object, consider re-linking"
Adding symbol sizes to .symbol files fixes this issue.
Instead of adding it everywhere manually, create a wrapper called
mesonlib.Popen_safe and use that everywhere that we call an executable
and extract its output.
This will also allow us to tweak it to do more/different things if
needed for some locales and/or systems.
Closes#1079
Nirbheek Chauhan
Dylan Baker
Arkadiusz Hiler
Igor Gnatenko
Marc-Antoine Perennou
Jussi Pakkanen
Elliott Sales de Andrade