2011-06-27 14:27:27 +07:00
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#ifndef _DWARF_AUX_H
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#define _DWARF_AUX_H
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/*
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* dwarf-aux.h : libdw auxiliary interfaces
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*
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*/
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#include <dwarf.h>
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#include <elfutils/libdw.h>
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#include <elfutils/libdwfl.h>
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#include <elfutils/version.h>
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/* Find the realpath of the target file */
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extern const char *cu_find_realpath(Dwarf_Die *cu_die, const char *fname);
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/* Get DW_AT_comp_dir (should be NULL with older gcc) */
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extern const char *cu_get_comp_dir(Dwarf_Die *cu_die);
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/* Get a line number and file name for given address */
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extern int cu_find_lineinfo(Dwarf_Die *cudie, unsigned long addr,
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const char **fname, int *lineno);
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2011-08-11 18:02:59 +07:00
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/* Walk on funcitons at given address */
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extern int cu_walk_functions_at(Dwarf_Die *cu_die, Dwarf_Addr addr,
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int (*callback)(Dwarf_Die *, void *), void *data);
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2012-04-23 10:24:36 +07:00
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/* Ensure that this DIE is a subprogram and definition (not declaration) */
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extern bool die_is_func_def(Dwarf_Die *dw_die);
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2015-01-30 16:37:44 +07:00
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/* Ensure that this DIE is an instance of a subprogram */
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extern bool die_is_func_instance(Dwarf_Die *dw_die);
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2011-06-27 14:27:27 +07:00
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/* Compare diename and tname */
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extern bool die_compare_name(Dwarf_Die *dw_die, const char *tname);
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2015-05-08 08:03:35 +07:00
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/* Matching diename with glob pattern */
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extern bool die_match_name(Dwarf_Die *dw_die, const char *glob);
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2011-06-27 14:27:27 +07:00
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/* Get callsite line number of inline-function instance */
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extern int die_get_call_lineno(Dwarf_Die *in_die);
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perf probe: Fix to search nested inlined functions in CU
Fix perf probe to walk through the lines of all nested inlined function
call sites and declared lines when a whole CU is passed to the line
walker.
The die_walk_lines() can have two different type of DIEs, subprogram (or
inlined-subroutine) DIE and CU DIE.
If a caller passes a subprogram DIE, this means that the walker walk on
lines of given subprogram. In this case, it just needs to search on
direct children of DIE tree for finding call-site information of inlined
function which directly called from given subprogram.
On the other hand, if a caller passes a CU DIE to the walker, this means
that the walker have to walk on all lines in the source files included
in given CU DIE. In this case, it has to search whole DIE trees of all
subprograms to find the call-site information of all nested inlined
functions.
Without this patch:
$ perf probe --line kernel/cpu.c:151-157
</home/mhiramat/ksrc/linux-2.6/kernel/cpu.c:151>
static int cpu_notify(unsigned long val, void *v)
{
154 return __cpu_notify(val, v, -1, NULL);
}
With this:
$ perf probe --line kernel/cpu.c:151-157
</home/mhiramat/ksrc/linux-2.6/kernel/cpu.c:151>
152 static int cpu_notify(unsigned long val, void *v)
{
154 return __cpu_notify(val, v, -1, NULL);
}
As you can see, --line option with source line range shows the declared
lines as probe-able.
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: yrl.pp-manager.tt@hitachi.com
Link: http://lkml.kernel.org/r/20110811110241.19900.34994.stgit@fedora15
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2011-08-11 18:02:41 +07:00
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/* Get callsite file name of inlined function instance */
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extern const char *die_get_call_file(Dwarf_Die *in_die);
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2011-06-27 14:27:27 +07:00
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/* Get type die */
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extern Dwarf_Die *die_get_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem);
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/* Get a type die, but skip qualifiers and typedef */
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extern Dwarf_Die *die_get_real_type(Dwarf_Die *vr_die, Dwarf_Die *die_mem);
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/* Check whether the DIE is signed or not */
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extern bool die_is_signed_type(Dwarf_Die *tp_die);
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/* Get data_member_location offset */
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extern int die_get_data_member_location(Dwarf_Die *mb_die, Dwarf_Word *offs);
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/* Return values for die_find_child() callbacks */
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enum {
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DIE_FIND_CB_END = 0, /* End of Search */
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DIE_FIND_CB_CHILD = 1, /* Search only children */
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DIE_FIND_CB_SIBLING = 2, /* Search only siblings */
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DIE_FIND_CB_CONTINUE = 3, /* Search children and siblings */
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};
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/* Search child DIEs */
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extern Dwarf_Die *die_find_child(Dwarf_Die *rt_die,
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int (*callback)(Dwarf_Die *, void *),
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void *data, Dwarf_Die *die_mem);
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/* Search a non-inlined function including given address */
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extern Dwarf_Die *die_find_realfunc(Dwarf_Die *cu_die, Dwarf_Addr addr,
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Dwarf_Die *die_mem);
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perf probe: Fix to find line information for probe list
Fix to find the correct (as much as possible) line information for
listing probes. Without this fix, perf probe --list action will show
incorrect line information as below;
probe:getname_flags (on getname_flags@ksrc/linux-3/fs/namei.c)
probe:getname_flags_1 (on getname:-89@x86/include/asm/current.h)
probe:getname_flags_2 (on user_path_at_empty:-2054@x86/include/asm/current.h)
The minus line number is obviously wrong, and current.h is not related
to the probe point. Deeper investigation discovered that there were 2
issues related to this bug, and minor typos too.
The 1st issue is the rack of considering about nested inlined functions,
which causes the wrong (relative) line number.
The 2nd issue is that the dwarf line info is not correct at those
points. It points 14th line of current.h.
Since it seems that the line info includes somewhat unreliable
information, this fixes perf to try to find correct line information
from both of debuginfo and line info as below.
1) Probe address is the entry of a function instance
In this case, the line is set as the function declared line.
2) Probe address is the entry of an expanded inline function block
In this case, the line is set as the function call-site line.
This means that the line number is relative from the entry line
of caller function (which can be an inlined function if nested)
3) Probe address is inside a function instance or an expanded
inline function block
In this case, perf probe queries the line number from lineinfo
and verify the function declared file is same as the file name
queried from lineinfo.
If the file name is different, it is a failure case. The probe
address is shown as symbol+offset.
4) Probe address is not in the any function instance
This is a failure case, the probe address is shown as
symbol+offset.
With this fix, perf probe -l shows correct probe lines as below;
probe:getname_flags (on getname_flags@ksrc/linux-3/fs/namei.c)
probe:getname_flags_1 (on getname:2@ksrc/linux-3/fs/namei.c)
probe:getname_flags_2 (on user_path_at_empty:4@ksrc/linux-3/fs/namei.c)
Changes at v2:
- Fix typos in the function comments. (Thanks to Namhyung Kim)
- Use die_find_top_inlinefunc instead of die_find_inlinefunc_next.
Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20130930092144.1693.11058.stgit@udc4-manage.rcp.hitachi.co.jp
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2013-09-30 16:21:44 +07:00
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/* Search the top inlined function including given address */
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extern Dwarf_Die *die_find_top_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr,
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Dwarf_Die *die_mem);
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/* Search the deepest inlined function including given address */
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2011-06-27 14:27:27 +07:00
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extern Dwarf_Die *die_find_inlinefunc(Dwarf_Die *sp_die, Dwarf_Addr addr,
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Dwarf_Die *die_mem);
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2011-08-11 18:03:11 +07:00
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/* Walk on the instances of given DIE */
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extern int die_walk_instances(Dwarf_Die *in_die,
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int (*callback)(Dwarf_Die *, void *), void *data);
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2011-06-27 14:27:27 +07:00
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/* Walker on lines (Note: line number will not be sorted) */
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typedef int (* line_walk_callback_t) (const char *fname, int lineno,
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Dwarf_Addr addr, void *data);
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/*
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* Walk on lines inside given DIE. If the DIE is a subprogram, walk only on
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* the lines inside the subprogram, otherwise the DIE must be a CU DIE.
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*/
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extern int die_walk_lines(Dwarf_Die *rt_die, line_walk_callback_t callback,
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void *data);
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/* Find a variable called 'name' at given address */
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extern Dwarf_Die *die_find_variable_at(Dwarf_Die *sp_die, const char *name,
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Dwarf_Addr addr, Dwarf_Die *die_mem);
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/* Find a member called 'name' */
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extern Dwarf_Die *die_find_member(Dwarf_Die *st_die, const char *name,
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Dwarf_Die *die_mem);
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/* Get the name of given variable DIE */
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2015-05-11 16:25:02 +07:00
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extern int die_get_typename(Dwarf_Die *vr_die, struct strbuf *buf);
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2011-06-27 14:27:27 +07:00
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/* Get the name and type of given variable DIE, stored as "type\tname" */
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2015-05-11 16:25:02 +07:00
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extern int die_get_varname(Dwarf_Die *vr_die, struct strbuf *buf);
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perf probe: Add --range option to show a variable's location range
It is not easy for users to get the accurate byte offset or the line
number where a local variable can be probed.
With '--range' option, local variables in the scope of the probe point
are showed with a byte offset range, and can be added according to this
range information.
For example, there are some variables in the function
generic_perform_write():
<generic_perform_write@mm/filemap.c:0>
0 ssize_t generic_perform_write(struct file *file,
1 struct iov_iter *i, loff_t pos)
2 {
3 struct address_space *mapping = file->f_mapping;
4 const struct address_space_operations *a_ops = mapping->a_ops;
...
42 status = a_ops->write_begin(file, mapping, pos, bytes, flags,
&page, &fsdata);
44 if (unlikely(status < 0))
But we fail when we try to probe the variable 'a_ops' at line 42 or 44.
$ perf probe --add 'generic_perform_write:42 a_ops'
Failed to find the location of a_ops at this address.
Perhaps, it has been optimized out.
This is because the source code do not match the assembly, so a variable
may not be available in the source code line where it appears.
After this patch, we can lookup the accurate byte offset range of a
variable, 'INV' indicates that this variable is not valid at the given
point, but available in the scope:
$ perf probe --vars 'generic_perform_write:42' --range
Available variables at generic_perform_write:42
@<generic_perform_write+141>
[INV] ssize_t written @<generic_perform_write+[324-331]>
[INV] struct address_space_operations* a_ops @<generic_perform_write+[55-61,170-176,223-246]>
[VAL] (unknown_type) fsdata @<generic_perform_write+[70-307,346-411]>
[VAL] loff_t pos @<generic_perform_write+[0-286,286-336,346-411]>
[VAL] long int status @<generic_perform_write+[83-342,346-411]>
[VAL] long unsigned int bytes @<generic_perform_write+[122-311,320-338,346-403,403-411]>
[VAL] struct address_space* mapping @<generic_perform_write+[35-344,346-411]>
[VAL] struct iov_iter* i @<generic_perform_write+[0-340,346-411]>
[VAL] struct page* page @<generic_perform_write+[70-307,346-411]>
Then it is more clear for us to add a probe with this variable:
$ perf probe --add 'generic_perform_write+170 a_ops'
Added new event:
probe:generic_perform_write (on generic_perform_write+170 with a_ops)
Signed-off-by: He Kuang <hekuang@huawei.com>
Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1431336304-16863-2-git-send-email-hekuang@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-05-11 16:25:03 +07:00
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extern int die_get_var_range(Dwarf_Die *sp_die, Dwarf_Die *vr_die,
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struct strbuf *buf);
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2011-06-27 14:27:27 +07:00
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#endif
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