Support #[unix_sigpipe = "inherit|sig_dfl|sig_ign"] on fn main()

This makes it possible to instruct libstd to never touch the signal
handler for `SIGPIPE`, which makes programs pipeable by default (e.g.
with `./your-program | head -n 1`) without `ErrorKind::BrokenPipe`
errors.
This commit is contained in:
Martin Nordholts 2022-07-05 19:56:22 +02:00
parent ee285eab69
commit ddee45e1d7
46 changed files with 449 additions and 43 deletions

View file

@ -1,7 +1,7 @@
use rustc_hir::LangItem;
use rustc_middle::ty::subst::GenericArg;
use rustc_middle::ty::AssocKind;
use rustc_session::config::EntryFnType;
use rustc_session::config::{sigpipe, EntryFnType};
use rustc_span::symbol::Ident;
use crate::prelude::*;
@ -15,12 +15,12 @@ pub(crate) fn maybe_create_entry_wrapper(
is_jit: bool,
is_primary_cgu: bool,
) {
let (main_def_id, is_main_fn) = match tcx.entry_fn(()) {
let (main_def_id, (is_main_fn, sigpipe)) = match tcx.entry_fn(()) {
Some((def_id, entry_ty)) => (
def_id,
match entry_ty {
EntryFnType::Main => true,
EntryFnType::Start => false,
EntryFnType::Main { sigpipe } => (true, sigpipe),
EntryFnType::Start => (false, sigpipe::DEFAULT),
},
),
None => return,
@ -35,7 +35,7 @@ pub(crate) fn maybe_create_entry_wrapper(
return;
}
create_entry_fn(tcx, module, unwind_context, main_def_id, is_jit, is_main_fn);
create_entry_fn(tcx, module, unwind_context, main_def_id, is_jit, is_main_fn, sigpipe);
fn create_entry_fn(
tcx: TyCtxt<'_>,
@ -44,6 +44,7 @@ pub(crate) fn maybe_create_entry_wrapper(
rust_main_def_id: DefId,
ignore_lang_start_wrapper: bool,
is_main_fn: bool,
sigpipe: u8,
) {
let main_ret_ty = tcx.fn_sig(rust_main_def_id).output();
// Given that `main()` has no arguments,
@ -83,6 +84,7 @@ pub(crate) fn maybe_create_entry_wrapper(
bcx.switch_to_block(block);
let arg_argc = bcx.append_block_param(block, m.target_config().pointer_type());
let arg_argv = bcx.append_block_param(block, m.target_config().pointer_type());
let arg_sigpipe = bcx.ins().iconst(types::I8, sigpipe as i64);
let main_func_ref = m.declare_func_in_func(main_func_id, &mut bcx.func);
@ -143,7 +145,8 @@ pub(crate) fn maybe_create_entry_wrapper(
let main_val = bcx.ins().func_addr(m.target_config().pointer_type(), main_func_ref);
let func_ref = m.declare_func_in_func(start_func_id, &mut bcx.func);
let call_inst = bcx.ins().call(func_ref, &[main_val, arg_argc, arg_argv]);
let call_inst =
bcx.ins().call(func_ref, &[main_val, arg_argc, arg_argv, arg_sigpipe]);
bcx.inst_results(call_inst)[0]
} else {
// using user-defined start fn