lldb reports my remote aarch64 paltform as x86_64 (AOSP) - android-source

Question

I'm trying to remotely debug a process on my aarch64 hardware. Why does the triplet start with x86_64? I would expect aarch64
(lldb) platform select remote-android
Platform: remote-android
Connected: no
(lldb) platform connect connect://localhost:5039
Platform: remote-android
Triple: x86_64-unknown-linux-android
OS Version: 30 (5.4.47-07670-gd50c0c10c465)
Hostname: localhost
Connected: yes
WorkingDir: /
Kernel: #136 SMP PREEMPT Thu Nov 26 11:09:46 EST 2020
My Android hardware is aarch64. I pushed lldb-server to the target with
adb push prebuilts/clang/host/linux-x86/clang-r383902b/runtimes_ndk_cxx/aarch64/lldb-server /data/local/tmp/lldb-server
Ran it with:
adb shell /data/local/tmp/lldb-server platform --listen "*:5039" --server
And connected with lldb (from prebuilts/clang/host/linux-x86/clang-r383902b/bin/lldb)
I am able to attach to processes on the target, even list processes (which show x86_64 triplets again to my confusing) but I can't add any symbols files, or target create. Those commands yield arch errors which is what led me back to the triplet in the platform command. (side note, I do build with -Wl,--build-id=sha1 -g -glldb)
When I see tutorials online, they're triplets report arm.
Notes:
Everything is done from the shell (no IDE),
Not running in Docker,
My hardware is rooted and even in permissive mode right now
Everything here is based on AOSP 11
clang tag: clang-r383902b

Answer 1

The cause of this was the clang version I was using, clang-r383902b. Setting my local manifest to pull from master and using clang-r399163b everything worked.
Specifically:
Extend the clang prebuid project in a local manifest
<?xml version="1.0" encoding="UTF-8"?>
<manifest>
<remote name="aosp" fetch="https://android.googlesource.com/" review="https://android-review.googlesource.com/" />
<extend-project path="prebuilts/clang/host/linux-x86" name="platform/prebuilts/clang/host/linux-x86" groups="trusty" revision="refs/heads/master" clone-depth="1" remote="aosp" />
</manifest>
Sync: repo sync -d prebuilts/clang/host/linux-x86
Re-push: CLANG_TAG=clang-r399163b adb push prebuilts/clang/host/linux-x86/${CLANG_TAG}/runtimes_ndk_cxx/aarch64/lldb-server /data/local/tmp/lldb-server (or whatever the newest tag is)
Re-run lldb-server
I experimented with using the newest lldb-server with the existing lldb and it still worked.