Re: [PATCH 3/4] perf probe: Enable --range option according to libdw version

[Masami Hiramatsu]

On 2015/07/01 18:05, He Kuang wrote:
> The option --range uses functions in libdw (elfutils version >= 1.57),
> this patch check if elfutils version meets the requirements before
> enable this feature, so that perf can be built with old libdw.

Is that related to any libdw bug ? or you need to use newer API?
Please tell us more precise report or actual URL/bug number.

Thank you,

> 
> Reported-by: Alexei Starovoitov <alexei.starovoitov@xxxxxxxxx>
> Signed-off-by: He Kuang <hekuang@xxxxxxxxxx>
> ---
>  tools/perf/builtin-probe.c  |  2 ++
>  tools/perf/util/dwarf-aux.c |  2 ++
>  tools/perf/util/dwarf-aux.h | 13 ++++++++++++-
>  3 files changed, 16 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/perf/builtin-probe.c b/tools/perf/builtin-probe.c
> index 1272559..2760c06 100644
> --- a/tools/perf/builtin-probe.c
> +++ b/tools/perf/builtin-probe.c
> @@ -372,8 +372,10 @@ __cmd_probe(int argc, const char **argv, const char *prefix __maybe_unused)
>  		     "Show accessible variables on PROBEDEF", opt_show_vars),
>  	OPT_BOOLEAN('\0', "externs", &probe_conf.show_ext_vars,
>  		    "Show external variables too (with --vars only)"),
> +#if _ELFUTILS_PREREQ(0, 157)
>  	OPT_BOOLEAN('\0', "range", &probe_conf.show_location_range,
>  		"Show variables location range in scope (with --vars only)"),
> +#endif
>  	OPT_STRING('k', "vmlinux", &symbol_conf.vmlinux_name,
>  		   "file", "vmlinux pathname"),
>  	OPT_STRING('s', "source", &symbol_conf.source_prefix,
> diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c
> index 57f3ef4..2cb4c82 100644
> --- a/tools/perf/util/dwarf-aux.c
> +++ b/tools/perf/util/dwarf-aux.c
> @@ -950,6 +950,7 @@ int die_get_varname(Dwarf_Die *vr_die, struct strbuf *buf)
>  	return 0;
>  }
>  
> +#if _ELFUTILS_PREREQ(0, 157)
>  /**
>   * die_get_var_innermost_scope - Get innermost scope range of given variable DIE
>   * @sp_die: a subprogram DIE
> @@ -1071,3 +1072,4 @@ int die_get_var_range(Dwarf_Die *sp_die, Dwarf_Die *vr_die, struct strbuf *buf)
>  
>  	return ret;
>  }
> +#endif /* _ELFUTILS_PREREQ(0, 157) */
> diff --git a/tools/perf/util/dwarf-aux.h b/tools/perf/util/dwarf-aux.h
> index c42ec36..ade0c50 100644
> --- a/tools/perf/util/dwarf-aux.h
> +++ b/tools/perf/util/dwarf-aux.h
> @@ -125,6 +125,17 @@ extern int die_get_typename(Dwarf_Die *vr_die, struct strbuf *buf);
>  
>  /* Get the name and type of given variable DIE, stored as "type\tname" */
>  extern int die_get_varname(Dwarf_Die *vr_die, struct strbuf *buf);
> +#if _ELFUTILS_PREREQ(0, 157)
>  extern int die_get_var_range(Dwarf_Die *sp_die, Dwarf_Die *vr_die,
> -			struct strbuf *buf);
> +			     struct strbuf *buf);
> +#else
> +static inline
> +int die_get_var_range(Dwarf_Die *sp_die __maybe_unused,
> +		      Dwarf_Die *vr_die __maybe_unused,
> +		      struct strbuf *buf __maybe_unused)
> +{
> +	return -ENOTSUP;
> +}
> +
> +#endif /* _ELFUTILS_PREREQ(0, 157) */
>  #endif
> 


-- 
Masami HIRAMATSU
Linux Technology Research Center, System Productivity Research Dept.
Center for Technology Innovation - Systems Engineering
Hitachi, Ltd., Research & Development Group
E-mail: masami.hiramatsu.pt@xxxxxxxxxxx
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