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Flush executables to disk after linkage

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A problem caused by not doing so in Chrome has been reported here:
https://randomascii.wordpress.com/2018/02/25/compiler-bug-linker-bug-windows-kernel-bug/amp/

File::sync_all() calls FlushFileBuffers() down the line,
causing potentially unflushed buffers on high I/O-load systems to flush
and prevent nasty non-reproducible bugs.

The force-flush is only done on Windows and if the linker exited successfully

Closes #48545
This commit is contained in:
nabijaczleweli 2018-03-27 23:09:35 +02:00
parent 9c9424de51
commit cd09c2b2ab
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GPG key ID: BCFD0B018D2658F1
1 changed files with 33 additions and 3 deletions
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36
src/librustc_trans/back/link.rs
View file

@ -692,7 +692,7 @@ fn link_natively(sess: &Session,
loop {
i += 1;
prog = time(sess, "running linker", || {
exec_linker(sess, &mut cmd, tmpdir)
exec_linker(sess, &mut cmd, out_filename, tmpdir)
});
let output = match prog {
Ok(ref output) => output,
@ -819,7 +819,7 @@ fn link_natively(sess: &Session,
}
}
fn exec_linker(sess: &Session, cmd: &mut Command, tmpdir: &Path)
fn exec_linker(sess: &Session, cmd: &mut Command, out_filename: &Path, tmpdir: &Path)
-> io::Result<Output>
{
// When attempting to spawn the linker we run a risk of blowing out the
@ -867,7 +867,37 @@ fn exec_linker(sess: &Session, cmd: &mut Command, tmpdir: &Path)
fs::write(&file, &bytes)?;
cmd2.arg(format!("@{}", file.display()));
info!("invoking linker {:?}", cmd2);
return cmd2.output();
let output = cmd2.output();
flush_linked_file(&output, out_filename)?;
return output;
#[cfg(unix)]
fn flush_linked_file(_: &io::Result<Output>, _: &Path) -> io::Result<()> {
Ok(())
}
#[cfg(windows)]
fn flush_linked_file(command_output: &io::Result<Output>, out_filename: &Path)
-> io::Result<()>
{
// On Windows, under high I/O load, output buffers are sometimes not flushed,
// even long after process exit, causing nasty, non-reproducible output bugs.
//
// File::sync_all() calls FlushFileBuffers() down the line, which solves the problem.
//
// А full writeup of the original Chrome bug can be found at
// randomascii.wordpress.com/2018/02/25/compiler-bug-linker-bug-windows-kernel-bug/amp
if let &Ok(ref out) = command_output {
if out.status.success() {
if let Ok(of) = fs::File::open(out_filename) {
of.sync_all()?;
}
}
}
Ok(())
}
#[cfg(unix)]
fn command_line_too_big(err: &io::Error) -> bool {