Strange linking behaviour in conjunction with ARM-EABI unwinding routines (__cxa_begin_cleanup)

[Andreas Schwab]

On Sep 12 2017, "Thomas Schmid via binutils" <binutils@sourceware.org> wrote:

> When I compile and link a simple C++-library consisting of the files
> test.cpp, TestClass.cpp, TestClass.h
> some unwinding support routines like '__cxa_begin_cleanup' are
> weak-referenced from the library,
> 'objdump -T' showing them as
>    00000000  w   D  *UND*  00000000 __cxa_begin_cleanup
>    00000000  w   D  *UND*  00000000 __cxa_call_unexpected
>
> '__cxa_begin_cleanup' is implemented in libsupc++, which our library is
> linked with, but the function is not linked into the library.
> Why?

Weak references don't pull in archive members.

Andreas.

-- 
Andreas Schwab, SUSE Labs, schwab@suse.de
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