linux-kernel - Re: [PATCH 17/17] perf annotate: Handle variables in 'sub', 'or' and many other instructions

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Message-ID: <20180417025628.GB31947@sejong>
Date:   Tue, 17 Apr 2018 11:56:28 +0900
From:   Namhyung Kim <namhyung@...nel.org>
To:     Andi Kleen <ak@...ux.intel.com>
Cc:     Arnaldo Carvalho de Melo <acme@...nel.org>,
        Ingo Molnar <mingo@...nel.org>,
        Clark Williams <williams@...hat.com>,
        linux-kernel@...r.kernel.org, linux-perf-users@...r.kernel.org,
        Arnaldo Carvalho de Melo <acme@...hat.com>,
        Adrian Hunter <adrian.hunter@...el.com>,
        David Ahern <dsahern@...il.com>,
        Jin Yao <yao.jin@...ux.intel.com>,
        Jiri Olsa <jolsa@...nel.org>,
        Martin Liška <mliska@...e.cz>,
        Ravi Bangoria <ravi.bangoria@...ux.vnet.ibm.com>,
        Thomas Richter <tmricht@...ux.vnet.ibm.com>,
        Wang Nan <wangnan0@...wei.com>, kernel-team@....com
Subject: Re: [PATCH 17/17] perf annotate: Handle variables in 'sub', 'or' and
 many other instructions

Hi,

On Fri, Apr 13, 2018 at 10:39:40AM -0700, Andi Kleen wrote:
> > What do I miss? Or where is it that I'm misinterpreting the calculations
> > that objdump did in its output?
> 
> The calculations are right, but these are still two different address modes.
> You cannot just turn one silently into the other.
> 
> I think it would be ok to use the syntax in the assembler
> 
> symbol(%rip)  with no # ...

One thing I find useful is to show string constant if the address is
in the rodata (and printable of course).  Maybe something like below..

  lea    0x1234(%rip),%rdi    # "hello world\n"
  callq  printf


Just an idea.

Thanks,
Namhyung


> 
> > About something mildly related: what do you think about this:
> > http://ref.x86asm.net/, there is a xml file there[1] I'm thinking about
> > using, if available on the developer's HOME or some other standard place,
> > to provide help about the instructions :-)
> 
> I don't know how well it's going to be maintained. x86 changes a lot
> and I've seen a lot of disassembler libraries etc. go stale as the
> owner cannot keep up.
> 
> The only semi official maintained descriptions are the XED tables (but those
> don't have descriptions) or the PDFs from Intel/AMD.
> I suppose could have some hack that talks to a PDF reader and automatically
> downloads/searches the PDF.
> 
> If unofficial is ok I would rather port some functionality
> from https://github.com/HJLebbink/asm-dude
> which has a lot of cool stuff.
> 
> -Andi