[cfe-dev] libc++/libc++abi - compilation on armv7

[Goncalo Carvalho]

Hi,


I've been trying to use libcxx and libcxxabi on an armv7 sbc running
arch linux. Although arch is distributing it is unusable since linking
with it fails with undefined references to

'undefined reference to `_Unwind_VRS_Interpret'

This is fine since it relies on the 'buildit' script which hasn't been
updated in a while, and it doesn't attempt to compile the sources in
the Unwind dir.

A readelf -s on the resulting .so confirms the symbol is undefined.

However, when using latest from the git repos I also get

"
/home/goncalo/swdev/llvm/projects/libcxxabi/src/cxa_personality.cpp:(.text._ZN10__cxxabiv113set_registersEP21_Unwind_Control_BlockP15_Unwind_ContextRKNS_12_GLOBAL__N_112scan_resultsE+0x50):
undefined reference to `_Unwind_SetIP'"

 since it appears to rely on
LIBCXXABI_USE_LLVM_UNWINDER, i.e,

cmake -DCMAKE_C_COMPILER=clang -DCMAKE_CXX_COMPILER=clang++
-DLIBCXXABI_USE_LLVM_UNWINDER=1 ..

but even with the above,

: undefined reference to `__aeabi_uidiv'

so it relies on linking against libgcc_s but that's missing from the
CMakeLists.txt. When adding it then I can build it :).

Although I haven't run the test suite a basic program links and
executes against it. A readelf -s against the .so confirms the symbols
exists.

The question then is the above expected, or simply arm sbc were never
considered as a possible platform and as such no one maintains it in
terms of getting it to compile and regression test?

Kind regards and thanks for reading!

Goncalo