Is anyone running our gdb-based Android debuginfo tests?

[saethlin]

This is mostly directed at @chriswailes, @maurer, and @mgeisler because you are the target maintainers for our Android targets.

I've been looking through our debuginfo tests, and I've found that a few of them were disabled years ago never revisited. Some of those tests are disabled only on Android. Based on the history linked from #10381, the last attempt to re-enable some of the mass-ignored android debuginfo tests was in 2015. So I'm not expecting any of you to really know the history here.

But currently (and I do not know for how long) we do not run any debuginfo tests on Android: https://github.com/rust-lang-ci/rust/actions/runs/10409799292/job/28830241725#step:25:23109

It seems like this is because compiletest looks for a gdb:

rust/src/tools/compiletest/src/lib.rs

Lines 1038 to 1085 in 0f442e2

	/// Returns (Path to GDB, GDB Version, GDB has Rust Support)
	fn analyze_gdb(
	gdb: Option<String>,
	target: &str,
	android_cross_path: &PathBuf,
	) -> (Option<String>, Option<u32>, bool) {
	#[cfg(not(windows))]
	const GDB_FALLBACK: &str = "gdb";
	#[cfg(windows)]
	const GDB_FALLBACK: &str = "gdb.exe";
	const MIN_GDB_WITH_RUST: u32 = 7011010;
	let fallback_gdb = || {
	if is_android_gdb_target(target) {
	let mut gdb_path = match android_cross_path.to_str() {
	Some(x) => x.to_owned(),
	None => panic!("cannot find android cross path"),
	};
	gdb_path.push_str("/bin/gdb");
	gdb_path
	} else {
	GDB_FALLBACK.to_owned()
	}
	};
	let gdb = match gdb {
	None => fallback_gdb(),
	Some(ref s) if s.is_empty() => fallback_gdb(), // may be empty if configure found no gdb
	Some(ref s) => s.to_owned(),
	};
	let mut version_line = None;
	if let Ok(output) = Command::new(&gdb).arg("--version").output() {
	if let Some(first_line) = String::from_utf8_lossy(&output.stdout).lines().next() {
	version_line = Some(first_line.to_string());
	}
	}
	let version = match version_line {
	Some(line) => extract_gdb_version(&line),
	None => return (None, None, false),
	};
	let gdb_native_rust = version.map_or(false, |v| v >= MIN_GDB_WITH_RUST);
	(Some(gdb), version, gdb_native_rust)
	}

but since compiletest doesn't find one, we skip the entire suite.

There is a fair amount of code in compiletest for handling debuginfo tests on Android. Since none of any of the code associated with running debuginfo tests on Android is currently being exercised, I suspect all of that code is just a time bomb for whoever eventually decides that we need those tests to be enabled.

In #128913 I am removing a number of ignore-test annotations from the test suite, and replacing them with more specific ignores where required. Because the entire suite is ignored for Android, I cannot do this.

So I have a few questions:

• Is anyone running the debuginfo test suite on Android?
• Would anyone object if I blindly remove all the other ignore-android annotations from the test suite?
• Is anyone planning on working to re-enable the Android debuginfo tests? I've poked around, and it uses a bunch of Android SDK/emulator arcana that I do not understand. For example, I tried installing gdb-multiarch in the image, which results in the test suite managing to execute arm-linux-androideabi-gdb (which I cannot find in the container) but if I add set architecture to the gdb commands, the output is just i686/x86_64.
• In my searching around for explanations about how to debug on Android, I found some mentions that one should be using lldb instead. Is that right?

[maurer]

I'm not currently working to re-enable these tests, and I don't expect to have time to do so soon.

If someone wanted to do this, rather than installing gdb-multiarch, use either ndk-lldb or ndk-gdb which are installed as part of the NDK we're fetching. Those should:

1. Have the right arch support
2. Know how to connect to a process running in the emulator to debug it

If someone was going to spend time getting one set of tests working, lldb would be massively preferred.

[mgeier]

@saethlin I think you meant to tag someone else, I'm not a maintainer for any target.

[saethlin]

Right you are. Sorry about that.