[libcxx-commits] [PATCH] D78787: [libcxx][libcxxabi][libunwind] Use libgcc on Android

Shoaib Meenai via Phabricator via libcxx-commits libcxx-commits at lists.llvm.org
Wed Apr 29 22:09:40 PDT 2020


smeenai added a comment.

In D78787#2011769 <https://reviews.llvm.org/D78787#2011769>, @rprichard wrote:

> > Hmm. On an Android 10 device (a Pixel 3), my `/system/lib64/libc.so` doesn't appear to export any unwind symbols. Both the x86 and x86_64 libc.so on my API 29 emulator don't appear to export any unwind symbols either. Was this a problem on older OS versions?
>
> Prior to the upcoming Android R (Android 11) release, only the arm32 libc.so exported unwinder symbols. The arm32 libc.so exported libgcc's unwinder and many of the internal unwinder symbols.
>
> As of R, unwinder symbols are exported from libc.so for all architectures. They're visible in the current R AVD image available through Android Studio. Only the public unwinder API is exported. arm32 now exports LLVM's libunwind, but other architectures export the libgcc unwinder.


Ah. Is the plan to eventually transition those other architectures to LLVM's libunwind as well (at which point the libc for those architectures would also expose LLVM's unwinder)?

>> Also, does this change make sense now?
> 
> Yeah, I'm OK with the change. It definitely makes more sense than linking with gcc_s on Android, which doesn't exist.
> 
> (I'm not sure who needs to accept the change.)

Given that this is Android-specific, I think it'd make sense for an Android person to sign off.


Repository:
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  https://reviews.llvm.org/D78787/new/

https://reviews.llvm.org/D78787





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