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From:   Namhyung Kim <namhyung@kernel.org>
Date:   Wed, 25 Oct 2023 22:26:32 -0700
Message-ID: <CAM9d7ciZ0axC1A=q2mT-5fCmNUZF=QtmfcQmfs8aR-tgYftYmA@mail.gmail.com>
Subject: Re: [PATCH 13/48] perf annotate: Add annotate_get_insn_location()
To:     Arnaldo Carvalho de Melo <acme@kernel.org>
Cc:     Jiri Olsa <jolsa@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Ian Rogers <irogers@google.com>,
        Adrian Hunter <adrian.hunter@intel.com>,
        Ingo Molnar <mingo@kernel.org>,
        LKML <linux-kernel@vger.kernel.org>,
        linux-perf-users@vger.kernel.org,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Stephane Eranian <eranian@google.com>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        linux-toolchains@vger.kernel.org, linux-trace-devel@vger.kernel.org
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On Tue, Oct 24, 2023 at 12:10 PM Namhyung Kim <namhyung@kernel.org> wrote:
>
> Hi Arnaldo,
>
> On Mon, Oct 23, 2023 at 9:38 AM Arnaldo Carvalho de Melo
> <acme@kernel.org> wrote:
> >
> > Em Wed, Oct 11, 2023 at 08:50:36PM -0700, Namhyung Kim escreveu:
> > > The annotate_get_insn_location() is to get the detailed information of
> > > instruction locations like registers and offset.  It has source and
> > > target operands locations in an array.  Each operand can have a
> > > register and an offset.  The offset is meaningful when mem_ref flag is
> > > set.
> >
> > This needs to be enclosed in HAVE_DWARF_SUPPORT, as the build is failing
> > in systems where this isn't available, see patch below.
>
> Thanks for the test and the patch, will add it to v2.

Hmm.. I think this function can work without DWARF.
If the only problem is get_dwarf_regnum() probably
I can add a dummy function when libdw is not found.
Maybe I need to use arch reg number here and
convert to DWARF later.

Thanks,
Namhyung


> >
> >   CC      /tmp/build/perf/arch/x86/util/pmu.o
> > util/annotate.c: In function 'extract_reg_offset':
> > util/annotate.c:3537:24: error: implicit declaration of function 'get_dwarf_regnum' [-Werror=implicit-function-declaration]
> >  3537 |         op_loc->reg1 = get_dwarf_regnum(regname, 0);
> >       |                        ^~~~~~~~~~~~~~~~
> >   CC      /tmp/build/perf/tests/vmlinux-kallsyms.o
> >
> > I tested it with 'make NO_DWARF=1'
> >
> > - Arnaldo
> >
> > diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c
> > index 9d653a1e84ce4889..b998c81c89be04fc 100644
> > --- a/tools/perf/util/annotate.c
> > +++ b/tools/perf/util/annotate.c
> > @@ -3486,6 +3486,7 @@ int annotate_check_args(struct annotation_options *args)
> >         return 0;
> >  }
> >
> > +#ifdef HAVE_DWARF_SUPPORT
> >  /*
> >   * Get register number and access offset from the given instruction.
> >   * It assumes AT&T x86 asm format like OFFSET(REG).  Maybe it needs
> > @@ -3591,3 +3592,4 @@ int annotate_get_insn_location(struct arch *arch, struct disasm_line *dl,
> >
> >         return 0;
> >  }
> > +#endif // HAVE_DWARF_SUPPORT
> > diff --git a/tools/perf/util/annotate.h b/tools/perf/util/annotate.h
> > index 4adda492233d2742..484be346a279c481 100644
> > --- a/tools/perf/util/annotate.h
> > +++ b/tools/perf/util/annotate.h
> > @@ -437,6 +437,7 @@ int annotate_parse_percent_type(const struct option *opt, const char *_str,
> >
> >  int annotate_check_args(struct annotation_options *args);
> >
> > +#ifdef HAVE_DWARF_SUPPORT
> >  /**
> >   * struct annotated_op_loc - Location info of instruction operand
> >   * @reg: Register in the operand
> > @@ -473,4 +474,5 @@ struct annotated_insn_loc {
> >  int annotate_get_insn_location(struct arch *arch, struct disasm_line *dl,
> >                                struct annotated_insn_loc *loc);
> >
> > +#endif /* HAVE_DWARF_SUPPORT */
> >  #endif /* __PERF_ANNOTATE_H */