question for marcus about rust's compiler_builtins and macosx_deployment_target

[Gagan Sidhu]

hi marcus

i’m working on making a firefox that works all the way back to 10.9

right now i am using it on 10.14 without issue, and i think the only thing left is ensuring rust honours my macosx_deployment_target

it seems rustc from macports (1.77.1) honours this variable for the most part, but i noticed one unusual thing.

when i use the mozilla toolchain’s rust (1.78), which has an implicit minimum of 10.12, i would get this:

> 34:32.52 ld64.lld: warning: ../../../x86_64-apple-darwin/release/libgkrust.a(std-b3629cc59bb38ebe.std.991b467e8ac0a4ad-cgu.0.rcgu.o) has version 10.12.0, which is newer than target minimum of 10.9.0
> 34:32.52 ld64.lld: warning: ../../../x86_64-apple-darwin/release/libgkrust.a(panic_abort-e0744c14fcbc8bcc.panic_abort.c40177b90b1e9efd-cgu.0.rcgu.o) has version 10.12.0, which is newer than target minimum of 10.9.0
> 34:32.52 ld64.lld: warning: ../../../x86_64-apple-darwin/release/libgkrust.a(object-5c7ad728062c8a84.object.804ec97e1ad5a55c-cgu.0.rcgu.o) has version 10.12.0, which is newer than target minimum of 10.9.0
> 34:32.53 ld64.lld: warning: ../../../x86_64-apple-darwin/release/libgkrust.a(memchr-90583dbfcd2cd9d8.memchr.5e40ebe02bc7fee7-cgu.0.rcgu.o) has version 10.12.0, which is newer than target minimum of 10.9.0
> 34:32.53 ld64.lld: warning: ../../../x86_64-apple-darwin/release/libgkrust.a(addr2line-f8a104b41642d585.addr2line.738d67e118a72e5c-cgu.0.rcgu.o) has version 10.12.0, which is newer than target minimum of 10.9.0
> 34:32.53 ld64.lld: warning: ../../../x86_64-apple-darwin/release/libgkrust.a(gimli-2dd3c1cbaa8c6ac2.gimli.25cd2fd39526eafa-cgu.0.rcgu.o) has version 10.12.0, which is newer than target minimum of 10.9.0
> 34:32.53 ld64.lld: warning: ../../../x86_64-apple-darwin/release/libgkrust.a(rustc_demangle-4b94f82697827b68.rustc_demangle.f3e6ea9654b87c89-cgu.0.rcgu.o) has version 10.12.0, which is newer than target minimum of 10.9.0
> 34:32.54 ld64.lld: warning: ../../../x86_64-apple-darwin/release/libgkrust.a(std_detect-526c5fbf4504f5c2.std_detect.cc21ff6764f76c21-cgu.0.rcgu.o) has version 10.12.0, which is newer than target minimum of 10.9.0
> 34:32.54 ld64.lld: warning: ../../../x86_64-apple-darwin/release/libgkrust.a(hashbrown-8983e26402bf8df3.hashbrown.c235b46fdb144bda-cgu.0.rcgu.o) has version 10.12.0, which is newer than target minimum of 10.9.0
> 34:32.55 ld64.lld: warning: ../../../x86_64-apple-darwin/release/libgkrust.a(alloc-81d461325d712857.alloc.803e2326cde23ec3-cgu.0.rcgu.o) has version 10.12.0, which is newer than target minimum of 10.9.0
> 34:32.55 ld64.lld: warning: ../../../x86_64-apple-darwin/release/libgkrust.a(core-4015b3a6e383e0ad.core.b03ae248d863ca2a-cgu.0.rcgu.o) has version 10.12.0, which is newer than target minimum of 10.9.0
> 34:32.55 ld64.lld: warning: ../../../x86_64-apple-darwin/release/libgkrust.a(compiler_builtins-d6175b4ffbd6f2cb.compiler_builtins.c536cea08157bc6d-cgu.021.rcgu.o) has version 10.12.0, which is newer than target minimum of 10.9.0
> 34:32.55 ld64.lld: warning: ../../../x86_64-apple-darwin/release/libgkrust.a(compiler_builtins-d6175b4ffbd6f2cb.compiler_builtins.c536cea08157bc6d-cgu.027.rcgu.o) has version 10.12.0, which is newer than target minimum of 10.9.0
> 34:32.56 ld64.lld: warning: ../../../x86_64-apple-darwin/release/libgkrust.a(compiler_builtins-d6175b4ffbd6f2cb.compiler_builtins.c536cea08157bc6d-cgu.034.rcgu.o) has version 10.12.0, which is newer than target minimum of 10.9.0
> 34:32.56 ld64.lld: warning: ../../../x86_64-apple-darwin/release/libgkrust.a(compiler_builtins-d6175b4ffbd6f2cb.compiler_builtins.c536cea08157bc6d-cgu.035.rcgu.o) has version 10.12.0, which is newer than target minimum of 10.9.0
> 34:32.56 ld64.lld: warning: ../../../x86_64-apple-darwin/release/libgkrust.a(compiler_builtins-d6175b4ffbd6f2cb.compiler_builtins.c536cea08157bc6d-cgu.061.rcgu.o) has version 10.12.0, which is newer than target minimum of 10.9.0
> 34:32.56 ld64.lld: warning: ../../../x86_64-apple-darwin/release/libgkrust.a(compiler_builtins-d6175b4ffbd6f2cb.compiler_builtins.c536cea08157bc6d-cgu.080.rcgu.o) has version 10.12.0, which is newer than target minimum of 10.9.0
> 34:32.57 ld64.lld: warning: ../../../x86_64-apple-darwin/release/libgkrust.a(compiler_builtins-d6175b4ffbd6f2cb.compiler_builtins.c536cea08157bc6d-cgu.084.rcgu.o) has version 10.12.0, which is newer than target minimum of 10.9.0
> 34:32.57 ld64.lld: warning: ../../../x86_64-apple-darwin/release/libgkrust.a(compiler_builtins-d6175b4ffbd6f2cb.compiler_builtins.c536cea08157bc6d-cgu.097.rcgu.o) has version 10.12.0, which is newer than target minimum of 10.9.0
> 34:32.57 ld64.lld: warning: ../../../x86_64-apple-darwin/release/libgkrust.a(compiler_builtins-d6175b4ffbd6f2cb.compiler_builtins.c536cea08157bc6d-cgu.008.rcgu.o) has version 10.12.0, which is newer than target minimum of 10.9.0
> 34:32.57 ld64.lld: warning: ../../../x86_64-apple-darwin/release/libgkrust.a(compiler_builtins-d6175b4ffbd6f2cb.compiler_builtins.c536cea08157bc6d-cgu.101.rcgu.o) has version 10.12.0, which is newer than target minimum of 10.9.0


but when i use the macports rust, i get this:
>  1:37.62 ld64.lld: warning: ../../../x86_64-apple-darwin/release/libgkrust.a(compiler_builtins-5cf596999632f69b.compiler_builtins.5e29af35305e20ca-cgu.045.rcgu.o) has version 10.14.0, which is newer than target minimum of 10.9.0
>  1:37.62 ld64.lld: warning: ../../../x86_64-apple-darwin/release/libgkrust.a(compiler_builtins-5cf596999632f69b.compiler_builtins.5e29af35305e20ca-cgu.053.rcgu.o) has version 10.14.0, which is newer than target minimum of 10.9.0
>  1:37.63 ld64.lld: warning: ../../../x86_64-apple-darwin/release/libgkrust.a(compiler_builtins-5cf596999632f69b.compiler_builtins.5e29af35305e20ca-cgu.060.rcgu.o) has version 10.14.0, which is newer than target minimum of 10.9.0
>  1:37.63 ld64.lld: warning: ../../../x86_64-apple-darwin/release/libgkrust.a(compiler_builtins-5cf596999632f69b.compiler_builtins.5e29af35305e20ca-cgu.068.rcgu.o) has version 10.14.0, which is newer than target minimum of 10.9.0
> 
obviously the macports version is much better, since it has reduced the number of warnings. but i found it unusual that it still left 4 compiler_builtins at a version higher than the mozilla rust.

is there any insight i could provide, or maybe you could share, that could help me remove these last 4 warnings?

Thanks,
Gagan