Re: [PATCH] Fix implicit conversion warning produced by clang

[John Baldwin <jhb@freebsd.org>]

On Tuesday, June 14, 2016 10:55:42 AM Taras Tsugrii wrote:
> When compiling with clang, which is part of Xcode 7.3, following warnings
> are emitted:
> objcopy.c:224:50: error: implicit conversion from enumeration type 'enum bfd_link_elf_stt_common' to different enumeration type 'enum bfd_link_discard' [-Werror,-Wenum-conversion]
> static enum bfd_link_discard do_elf_stt_common = unchanged;
>                              ~~~~~~~~~~~~~~~~~   ^~~~~~~~~
> objcopy.c:4290:26: error: implicit conversion from enumeration type 'enum bfd_link_elf_stt_common' to different enumeration type 'enum bfd_link_discard' [-Werror,-Wenum-conversion]
>             do_elf_stt_common = elf_stt_common;
>                               ~ ^~~~~~~~~~~~~~
> objcopy.c:4292:26: error: implicit conversion from enumeration type 'enum bfd_link_elf_stt_common' to different enumeration type 'enum bfd_link_discard' [-Werror,-Wenum-conversion]
>             do_elf_stt_common = no_elf_stt_common;
>                               ~ ^~~~~~~~~~~~~~~~~
> 3 errors generated.
> 
> This is risky, since essentially there is a coupling between 2 different
> enum orderings. Also since by default warnings are promoted to errors
> it breaks default build.

I had the same patch in queue and just pushed it.  I have a few more patches
from clang warnings pending as well.  (I am testing with clang 3.8.0 in
FreeBSD.)  Some of clang's warnings are a bit noisy though and I haven't tried
to address the -Wunused-function spam from VEC() (I presume that GDB will
eventually switch the VEC stuff to templates which will fix that).  Also,
Some of the -Wtautological-compare warnings for things that do:

	if (foo >= 0 && foo <= bar)

where 'foo' is unsigned I haven't posted patches to "fix" as I'm not sure that
the existing code isn't more readable in its current form.

-- 
John Baldwin