[Mesa-dev] [PATCH v2 2/2] gallium/util: Android backtrace support

[Stefan Schake]

On Tue, Apr 24, 2018 at 8:10 PM, Rob Herring <robh at kernel.org> wrote:
> On Sun, Apr 15, 2018 at 5:45 PM, Stefan Schake <stschake at gmail.com> wrote:
>> We can't use any of the existing implementations in u_debug_stack.
>> Android technically has libunwind, but it's been modified to the point
>> where it no longer compiles with the Mesa usage. The library is also
>> not meant to be referenced by vendor libraries. The officially sanctioned
>> way of obtaining backtraces is through the Android own libbacktrace, a
>> C++ library. Access it through a separate C++ source file on Android only.
>
> I know this is committed already, but it was pointed out to me that
> libbacktrace is not a visible library in Treble-ized builds. It is in
> the vndk-sp-indirect list.
>

Hrm. I used this presentation for reference:

https://source.android.com/devices/architecture/images/vndk_design_android_o.pdf

And it seems to say SP-HAL may depend on VNDK-SP which
includes libbacktrace. Though looking into it I found this:

https://android.googlesource.com/platform/system/core/+/b7d92c4b96cebae6a60f5256c9173e46f325e860

Which does indeed seem to say not available to vendor. And instead
suggests yet another method of obtaining a call stack.

If this is runtime breaking for anyone, I'd suggest we simply revert the
series for now and I'll look into making it use the
now-really-vendor-available android::CallStack from libutils.

Sorry for the trouble,
Stefan