Errors when compiling C++ using cross GCC

[Mark G]

On Sun, Nov 20, 2016 at 1:09 PM, Florian Weimer <fw@deneb.enyo.de> wrote:

> next.  It seems to me it contains a statically-linked copy of libm.a,
> which really should not happen.

I think I can confirm this is what is happening. The other hypothesis
I had was that, during libstdc++ compilation _GLIBCXX_HAVE_FREXPL was
not defined. This would put in a stub that uses the double version of
frexp() in src/c++98/math_stubs_long_double.cc.

I confirmed that _GLIBCXX_HAVE_FREXPL is defined to 1 and I took a
peek at the assembly code of frexpl in libstdc++.so that was compiled
as part of the GCC build. It doesn't look like the wrapper was
compiled.

I went to go look at the assembly code for frexpl in libm.a and here I
came across something confusing:

$ grep -rH frexpl /emb-root/usr/lib/arm-linux-gnueabihf/libm.a
Binary file /emb-root/usr/lib/arm-linux-gnueabihf/libm.a matches

It sure is in there as a symbole. But...

$ arm-linux-gnueabihf-objdump -d
/emb-root/usr/lib/arm-linux-gnueabihf/libm.a |grep frexpl

Comes back with nothing. Odd.

Thanks,
Mark