aee941559 ("rust: recursively pull proc-macro dependencies as well")
had to be reverted (in a66cb97e8) because it broke Mesa cross
compilation. This happened because a C shared library was linked with
a Rust C-ABI static library, which caused it to inherit the proc macro
dependency the Rust static library was linked with.
The right way to handle this is for only Rust targets to inherit proc
macro dependencies from static libraries they link with. A Rust
executable, library, or whatever will need the proc macros its Rust
dependencies use, as illustrated in the test case that I've
reintroduced here.
I've verified that Mesa still cross compiles correctly with this
change. The same failure was also identified by the "rust/21
transitive dependencies" test case, but only when cross compiling, so
it wasn't caught by CI.
Co-authored-by: Xavier Claessens <xavier.claessens@collabora.com>
In the case r1 -> s1 -> s2 where s1 and s2 are uninstalled C static
libraries, the libs1.a rule does not depend on libs2.a. That means that
r1 rule must depend on both s1 and s2.
Pass link arguments directly down to linker by using `-C link-args=`
instead of letting rustc/linker resolve `-l` arguments. This solves
problems with e.g. +verbatim not being portable. Note that we also pass
`-l` args as `-Clink-args=-l` because rustc would otherwise reorder
arguments and put `-lstdc++` before `-Clink-args=libfoo++.a`.
However, when building a rlib/staticlib we should still use `-l`
arguments because that allows rustc to bundle static libraries we
link-whole. In that case, since there is no platform specific dynamic
linker, +verbatim works.
This also fix installed staticlib that now bundle uninstalled static
libraries it links to (recursively). This is done by putting them all
into self.link_whole_targets instead of putting their objects into
self.objects, and let rustc do the bundling. This has the extra
advantage that rustc can bundle static libries built with CustomTarget.
Disable bundling in all other cases, otherwise we could end up with
duplicated objects in static libraries, in diamond dependency graph
case.
Fixes: #12484
Alyssa Ross
Xavier Claessens
Jussi Pakkanen
Sebastian Dröge