lib.systems: introduce hasSharedLibraries

This commit adds `hasSharedLibraries` to `lib.systems`.

We need `plat.hasSharedLibraries` in order to know whether or not to
expect `gcc` (and many other tools) to emit shared libraries (like
`libgcc_s.so`).  Many of the GNU build scripts are smart enough that
if you configure them with `--enable-shared` on a platform (such as
`arm-none-eabi`) that doesn't support dynamic linking, they will
simply skip the shared libraries instead of aborting the
`configurePhase`.  Unfortunately the missing shared libraries in the
final build product cause very hard-to-troubleshoot problems later
on.

The alternative to introducing `hasSharedLibraries` would be to set
`isStatic` in these situations.  However doing so causes
`make-derivation.nix` to insert `-static` between the `pname` and
`hostPlatform` suffix, which is undesirable.

If at some point in the future we eliminate the `-static` suffix,
then `hasSharedLibraries` can be made equal to `!isStatic`.
This commit is contained in:
Adam Joseph 2023-06-28 23:49:38 -07:00
parent 931b8a4979
commit 6980e6b35a

View file

@ -86,7 +86,7 @@ rec {
# choice.
else "bfd";
extensions = rec {
sharedLibrary =
sharedLibrary = assert final.hasSharedLibraries;
/**/ if final.isDarwin then ".dylib"
else if final.isWindows then ".dll"
else ".so";
@ -132,6 +132,25 @@ rec {
# uname -r
release = null;
};
# It is important that hasSharedLibraries==false when the platform has no
# dynamic library loader. Various tools (including the gcc build system)
# have knowledge of which platforms are incapable of dynamic linking, and
# will still build on/for those platforms with --enable-shared, but simply
# omit any `.so` build products such as libgcc_s.so. When that happens,
# it causes hard-to-troubleshoot build failures.
hasSharedLibraries = with final;
(isAndroid || isGnu || isMusl # Linux (allows multiple libcs)
|| isDarwin || isSunOS || isOpenBSD || isFreeBSD || isNetBSD # BSDs
|| isCygwin || isMinGW # Windows
) && !isStatic;
# The difference between `isStatic` and `hasSharedLibraries` is mainly the
# addition of the `staticMarker` (see make-derivation.nix). Some
# platforms, like embedded machines without a libc (e.g. arm-none-eabi)
# don't support dynamic linking, but don't get the `staticMarker`.
# `pkgsStatic` sets `isStatic=true`, so `pkgsStatic.hostPlatform` always
# has the `staticMarker`.
isStatic = final.isWasm || final.isRedox;
# Just a guess, based on `system`