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e08cfd4bda
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>
119 lines
4.3 KiB
C
119 lines
4.3 KiB
C
#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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/* 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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/* 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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/* Compare diename and tname */
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extern bool die_compare_name(Dwarf_Die *dw_die, const char *tname);
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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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/* 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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/* 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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/* 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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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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/* 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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/* 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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extern int die_get_typename(Dwarf_Die *vr_die, char *buf, int len);
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/* Get the name and type of given variable DIE, stored as "type\tname" */
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extern int die_get_varname(Dwarf_Die *vr_die, char *buf, int len);
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#endif
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