Em Fri, Nov 27, 2020 at 02:48:55PM +0900, Masami Hiramatsu escreveu:
> Since some gcc generates a broken DWARF which lacks DW_AT_declaration
> attribute from the subprogram DIE of function prototype.
> (https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97060)
>
> So, in addition to the DW_AT_declaration check, we also check the
> subprogram DIE has DW_AT_inline or actual entry pc.
Thanks, applied and tested both patches on a fedora 33 system where
previously those tests were failing:
Committer testing:
# cat /etc/fedora-release
Fedora release 33 (Thirty Three)
#
Before:
# perf test vfs_getname
78: Use vfs_getname probe to get syscall args filenames :
FAILED!
79: Check open filename arg using perf trace + vfs_getname :
FAILED!
81: Add vfs_getname probe to get syscall args filenames :
FAILED!
#
After:
# perf test vfs_getname
78: Use vfs_getname probe to get syscall args filenames : Ok
79: Check open filename arg using perf trace + vfs_getname : Ok
81: Add vfs_getname probe to get syscall args filenames : Ok
#
- Arnaldo
> Reported-by: Thomas Richter
> Signed-off-by: Masami Hiramatsu
> ---
> tools/perf/util/dwarf-aux.c| 20 ++--
> tools/perf/util/probe-finder.c |3 +--
> 2 files changed, 19 insertions(+), 4 deletions(-)
>
> diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c
> index 03c1a39c312a..7b2d471a6419 100644
> --- a/tools/perf/util/dwarf-aux.c
> +++ b/tools/perf/util/dwarf-aux.c
> @@ -356,9 +356,25 @@ bool die_is_signed_type(Dwarf_Die *tp_die)
> bool die_is_func_def(Dwarf_Die *dw_die)
> {
> Dwarf_Attribute attr;
> + Dwarf_Addr addr = 0;
> +
> + if (dwarf_tag(dw_die) != DW_TAG_subprogram)
> + return false;
> +
> + if (dwarf_attr(dw_die, DW_AT_declaration, ))
> + return false;
>
> - return (dwarf_tag(dw_die) == DW_TAG_subprogram &&
> - dwarf_attr(dw_die, DW_AT_declaration, ) == NULL);
> + /*
> + * DW_AT_declaration can be lost from function declaration
> + * by gcc's bug #97060.
> + * So we need to check this subprogram DIE has DW_AT_inline
> + * or an entry address.
> + */
> + if (!dwarf_attr(dw_die, DW_AT_inline, ) &&
> + die_entrypc(dw_die, ) < 0)
> + return false;
> +
> + return true;
> }
>
> /**
> diff --git a/tools/perf/util/probe-finder.c b/tools/perf/util/probe-finder.c
> index 2c4061035f77..76dd349aa48d 100644
> --- a/tools/perf/util/probe-finder.c
> +++ b/tools/perf/util/probe-finder.c
> @@ -1885,8 +1885,7 @@ static int line_range_search_cb(Dwarf_Die *sp_die, void
> *data)
> if (lr->file && strtailcmp(lr->file, dwarf_decl_file(sp_die)))
> return DWARF_CB_OK;
>
> - if (die_is_func_def(sp_die) &&
> - die_match_name(sp_die, lr->function)) {
> + if (die_match_name(sp_die, lr->function) && die_is_func_def(sp_die)) {
> lf->fname = dwarf_decl_file(sp_die);
> dwarf_decl_line(sp_die, >offset);
> pr_debug("fname: %s, lineno:%d\n", lf->fname, lr->offset);
>
--
- Arnaldo
