Replace -Zon-broken-pipe=... with Externally Implementable Item #[std::io::on_broken_pipe]

[Enselic]

The code in this PR also acts as a regression test for the fix to #150588 which I will split out in a separate PR.

TODO

• Fix Hundreds of missing stability attribute errors with trivial Externally Implementable Item (eii) function in library/std #150514 first in a separate PR (see compiler: Make Externally Implementable Items (eii) in std build #150592)
• Too many to enumerate...

Tracking Issues:

• Tracking Issue for Externally Implementable Item #[std::io::on_broken_pipe] #150588
• Tracking Issue for externally implementable items #125418

[RalfJung]

I assume this is just for testing for now, but this hack is definitely not something we'd want to land.

The proper fix here is to implement EII in Miri, so that the real implementation gets invoked. We already have hacks in place to ignore std trying to change the host SIGPIPE disposition.

[Enselic]

Yep that was indeed a hack and not intended for review. I just wanted to see how far away I was from getting PR CI to pass.

Your comment was still helpful however. I have removed the code and replaced it with

            #[cfg(not(miri))]
            let on_broken_pipe = crate::io::on_broken_pipe();
            #[cfg(miri)] // FIXME: Add proper miri support. See https://github.com/rust-lang/rust/pull/150591#discussion_r2665432118.
            let on_broken_pipe = OnBrokenPipe::BackwardsCompatible;

and will probably create a proper issue for it later.

(Note that this code is still not ready for review.)

[rust-log-analyzer]

The job pr-check-2 failed! Check out the build log: (web) (plain enhanced) (plain)

Click to see the possible cause of the failure (guessed by this bot)

    Checking rustc_codegen_cranelift v0.1.0 (/checkout/compiler/rustc_codegen_cranelift)
error[E0425]: cannot find value `sigpipe` in this scope
  --> compiler/rustc_codegen_cranelift/src/main_shim.rs:88:59
   |
88 |             let arg_sigpipe = bcx.ins().iconst(types::I8, sigpipe as i64);
   |                                                           ^^^^^^^ not found in this scope

warning: unused import: `rustc_session::config::EntryFnType`
 --> compiler/rustc_codegen_cranelift/src/main_shim.rs:4:5
  |
---
   |                    ^^^^^^^^ method not found in `(rustc_span::def_id::DefId, EntryFnType)`
   |
help: one of the expressions' fields has a method of the same name
   |
22 |     if main_def_id.0.is_local() {
   |                    ++

error[E0308]: mismatched types
   --> compiler/rustc_codegen_cranelift/src/main_shim.rs:23:44
    |
---
                found tuple `(rustc_span::def_id::DefId, EntryFnType)`
note: associated function defined here
   --> /checkout/compiler/rustc_middle/src/ty/instance.rs:465:12
    |
465 |     pub fn mono(tcx: TyCtxt<'tcx>, def_id: DefId) -> Instance<'tcx> {
    |            ^^^^

error[E0308]: mismatched types
  --> compiler/rustc_codegen_cranelift/src/main_shim.rs:31:34
   |
31 |     create_entry_fn(tcx, module, main_def_id, is_jit);
   |     ---------------              ^^^^^^^^^^^ expected `DefId`, found `(DefId, EntryFnType)`
   |     |
   |     arguments to this function are incorrect
   |
   = note: expected struct `rustc_span::def_id::DefId`
               found tuple `(rustc_span::def_id::DefId, EntryFnType)`