korg/linux
0
0
Fork 0
mirror of https://mirrors.bfsu.edu.cn/git/linux.git synced 2024-11-11 20:48:49 +08:00
Code Issues Packages Projects Releases Wiki Activity

perf probe: Fix perf probe to find correct variable DIE

Browse Source 
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>
This commit is contained in:
Masami Hiramatsu 2014-05-29 21:19:30 +09:00 committed by Jiri Olsa
parent 0c188a07b6
commit 082f96a93e
1 changed files with 5 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
tools/perf/util/dwarf-aux.c
View File

@ -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