Explicitly pass -no-pie

[sfackler]

Some linkers (e.g. Debian and Arch's) that are configured to make PIEs
by default will make dynamically linked executables that don't actually
dynamically link to anything. Fix that by explicitly passing -no-pie in
those cases.

Closes #43647

I wasn't able to test this out manually - is there an easy way to make a suitable musl root?

[rust-highfive]

r? @nikomatsakis

(rust_highfive has picked a reviewer for you, use r? to override)

[sfackler]

r? @alexcrichton

[mattico]

https://github.com/emk/rust-musl-builder could help test this.

[sfackler]

Is that setup to build rustc itself? It needs a somewhat specialized setup with a libunwind.a as well as just MUSL.

[mattico]

Ah, well the old rust buildbot images may still work: https://github.com/rust-lang/rust-buildbot/blob/master/slaves/linux/Dockerfile

[alexcrichton]

Looks good to me! There's a bunch of conditions that lead up to passing -pie, and shouldn't we always pass -no-pie if we don't hit the -pie path?

r=me w/ that tweak (if ok) and once you're happy with some testing

[aidanhs]

This is not going to interact well with PR #40113, where pie is enabled all the time.

However, there's something interesting in #40113 (comment), where pie is enabled but it actually does produce 'statically linked dynamic binaries'. For comparison, first the output from the issue that motivated this PR (#43647):

$ file ./target/x86_64-unknown-linux-musl/debug/bla
./target/x86_64-unknown-linux-musl/debug/bla: ELF 64-bit LSB shared object, x86-64, version 1 (GNU/Linux), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, BuildID[sha1]=8c6e0c77c39c031c76d95379bfe2593165b13a70, with debug_info, not stripped

And from the 'native musl' PR:

~ $ file hello
hello: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, not stripped, with debug_info

Note there's no interpreter in the latter.

Since this is something we're going to have to do anyway, it'd be nice if we could figure out how to actually generate static binaries with pie enabled. cc @shizmob

[sfackler]

Ah, this PR may not be needed at all then, right?

[aidanhs]

Potentially, but I'm not sure what about the arch linker is causing it to generate binaries like that so I've no idea if it'll be fixed. Worth a shot though I suppose.

[sfackler]

I think I'll close this for now and check back in after #40113 lands.

[sfackler]

Reopening - r? @alexcrichton

[sfackler]

Oh, nevermind github seems unhappy with that - opening a new PR