diff options
| author | Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> | 2014-05-29 21:19:30 +0900 |
|---|---|---|
| committer | Jiri Olsa <jolsa@kernel.org> | 2014-06-04 14:49:20 +0200 |
| commit | 082f96a93eb5ba9bf771518a0dda590624568e8e (patch) | |
| tree | 99c66353045e9de25cf726d98a82bb371621341f /tools | |
| parent | 0c188a07b6a399e3df66534c29fef0a2082aaf57 (diff) | |
| download | lwn-082f96a93eb5ba9bf771518a0dda590624568e8e.tar.gz lwn-082f96a93eb5ba9bf771518a0dda590624568e8e.zip | |
perf probe: Fix perf probe to find correct variable DIE
Fix perf probe to find correct variable DIE which has location or
external instance by tracking down the lexical blocks.
Current die_find_variable() expects that the all variable DIEs
which has DW_TAG_variable have a location. However, since recent
dwarf information may have declaration variable DIEs at the
entry of function (subprogram), die_find_variable() returns it.
To solve this problem, it must track down the DIE tree to find
a DIE which has an actual location or a reference for external
instance.
e.g. finding a DIE which origin is <0xdc73>;
<1><11496>: Abbrev Number: 95 (DW_TAG_subprogram)
<11497> DW_AT_abstract_origin: <0xdc42>
<1149b> DW_AT_low_pc : 0x1850
[...]
<2><114cc>: Abbrev Number: 119 (DW_TAG_variable) <- this is a declaration
<114cd> DW_AT_abstract_origin: <0xdc73>
<2><114d1>: Abbrev Number: 119 (DW_TAG_variable)
[...]
<3><115a7>: Abbrev Number: 105 (DW_TAG_lexical_block)
<115a8> DW_AT_ranges : 0xaa0
<4><115ac>: Abbrev Number: 96 (DW_TAG_variable) <- this has a location
<115ad> DW_AT_abstract_origin: <0xdc73>
<115b1> DW_AT_location : 0x486c (location list)
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Tested-by: Arnaldo Carvalho de Melo <acme@kernel.org>
Acked-by: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/20140529121930.30879.87092.stgit@ltc230.yrl.intra.hitachi.co.jp
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/perf/util/dwarf-aux.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/tools/perf/util/dwarf-aux.c b/tools/perf/util/dwarf-aux.c index 7defd77105d0..cc66c4049e09 100644 --- a/tools/perf/util/dwarf-aux.c +++ b/tools/perf/util/dwarf-aux.c @@ -747,14 +747,17 @@ struct __find_variable_param { static int __die_find_variable_cb(Dwarf_Die *die_mem, void *data) { struct __find_variable_param *fvp = data; + Dwarf_Attribute attr; int tag; tag = dwarf_tag(die_mem); if ((tag == DW_TAG_formal_parameter || tag == DW_TAG_variable) && - die_compare_name(die_mem, fvp->name)) + die_compare_name(die_mem, fvp->name) && + /* Does the DIE have location information or external instance? */ + (dwarf_attr(die_mem, DW_AT_external, &attr) || + dwarf_attr(die_mem, DW_AT_location, &attr))) return DIE_FIND_CB_END; - if (dwarf_haspc(die_mem, fvp->addr)) return DIE_FIND_CB_CONTINUE; else |