[Buildroot] [PATCH 1/1] package/erlang-jiffy: needs -fPIC
Thomas Petazzoni
thomas.petazzoni at bootlin.com
Fri Jan 1 10:37:28 UTC 2021
Hello,
On Fri, 1 Jan 2021 11:01:53 +0100
"Yann E. MORIN" <yann.morin.1998 at free.fr> wrote:
> The thing with LTO, is that all files should (but in practice: must) be
> compiled with the same set of options; from the gcc man page:
>
> It is recommended that you compile all the files participating in
> the same link with the same options and also specify those options
> at link time.
>
> and later:
>
> There are some code generation flags preserved by GCC when generating
> bytecodes, as they need to be used during the final link. Currently,
> the following options and their settings are taken from the first
> object file that explicitly specifies them: -fPIC, [...]
>
> So, if one file is compiled with -fPIC, then this is recorded in the .o
> for that file, which gcc notices later when doing the link, and thus all
> files must be -fPIC.
>
> This can be a file compiled by the package itself, or it may come from
> an external (staging) static library.
Ah, this is indeed an interesting explanation, which could explain why
adding it just to LDFLAGS solves the problem.
Thomas
--
Thomas Petazzoni, CTO, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com
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