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pass correct pie args to gcc linker 2

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Recent versions of gcc default to creating a position independent
executable and must be explicitly told not to with the -no-pie argument.

Old versions of gcc don't understand -no-pie and will throw an error.
Check for that case and retry without -no-pie. This is safe because
these old versions of gcc should never default to creating a position
independent executable.
This commit is contained in:
Jimmy Brush 2018-02-10 13:16:59 -05:00
parent 16350526d8
commit 8a72f589e5
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GPG key ID: 8C0A2907991F5664
1 changed files with 23 additions and 43 deletions
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64
src/librustc_trans/back/link.rs
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@ -652,9 +652,6 @@ fn link_natively(sess: &Session,
prog = time(sess.time_passes(), "running linker", || {
exec_linker(sess, &mut cmd, tmpdir)
});
if !retry_on_segfault || i > 3 {
break
}
let output = match prog {
Ok(ref output) => output,
Err(_) => break,
@ -665,6 +662,26 @@ fn link_natively(sess: &Session,
let mut out = output.stderr.clone();
out.extend(&output.stdout);
let out = String::from_utf8_lossy(&out);
// Check to see if the link failed with "unrecognized command line option:
// '-no-pie'". If so, reperform the link step without the -no-pie option. This
// is safe because if the linker doesn't support -no-pie then it should not
// default to linking executables as pie. Different versions of gcc seem to
// use different quotes in the error message so don't check for them.
if out.contains("unrecognized command line option") && out.contains("-no-pie") {
info!("linker output: {:?}", out);
warn!("Linker does not support -no-pie command line option. Retrying without.");
for arg in cmd.take_args() {
if arg.to_string_lossy() != "-no-pie" {
cmd.arg(arg);
}
}
info!("{:?}", &cmd);
continue;
}
if !retry_on_segfault || i > 3 {
break
}
let msg_segv = "clang: error: unable to execute command: Segmentation fault: 11";
let msg_bus = "clang: error: unable to execute command: Bus error: 10";
if !(out.contains(msg_segv) || out.contains(msg_bus)) {
@ -912,18 +929,10 @@ fn link_args(cmd: &mut Linker,
}
}
// Check to see if gcc defaults to generating a position independent
// executable. If so, tell it when to disable pie. Otherwise, tell it
// when to enable it. We can't do both because older versions of gcc
// don't understand -no-pie and will blow up.
if is_pie_default(sess) {
if !position_independent_executable {
cmd.no_position_independent_executable();
}
} else {
if position_independent_executable {
cmd.position_independent_executable();
}
} else {
cmd.no_position_independent_executable();
}
}
@ -1438,32 +1447,3 @@ fn is_full_lto_enabled(sess: &Session) -> bool {
Lto::ThinLocal => false,
}
}
fn is_pie_default(sess: &Session) -> bool {
match sess.linker_flavor() {
LinkerFlavor::Gcc => {
let (_, mut cmd, envs) = get_linker(sess);
// This will set PATH on windows
cmd.envs(envs);
cmd.arg("-v");
info!("{:?}", &cmd);
let output = cmd.command()
.stdout(Stdio::piped()).stderr(Stdio::piped())
.spawn()
.unwrap()
.wait_with_output()
.unwrap();
let ret = String::from_utf8_lossy(&output.stderr)
.contains("--enable-default-pie");
info!("gcc {} compiled with --enable-default-pie",
if ret { "IS" } else { "is NOT" });
ret
},
_ => false,
}
}