Re: [PATCH perf 3/4] perf tools: Fix unused variables: x86_{32,64}_regoffset_table

From: Arnaldo Carvalho de Melo
Date: Thu Jan 21 2016 - 10:38:59 EST


Em Thu, Jan 21, 2016 at 12:43:04PM +0800, Wangnan (F) escreveu:
> I think this problem is not introduced by my patch. In fact
> there's a fundamental problem in get_arch_regstr() that it is
> impossible to switch sub ISA.

> Not only x86_64 and x86_32, I think on arm64 we also have this
> problem when we try to setup uprobes on arm32 code. For me the
> later problem is more important because there are many legacy arm32
> applications on Android platform (and I have already seen the buggy
> unwind result in this case. It is another problem though).

Humm, and possibly to do something with arm code on a x86 workstation,
even if just analysis, yeah, I think these functions should take as an
argument the desired architecture instead of assuming it is the one in
the machine issuing the commands.

> So I suggest us to solve this problem first before considering
> gcc 6 Werror. At least x86_32_regoffset_table and x86_64_regoffset_table
> should both be compiled no matter which ISA we select for perf.
>
> Thank you.