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Message-ID: <aWVQ63NemEu5mNZo@x1>
Date: Mon, 12 Jan 2026 16:52:11 -0300
From: Arnaldo Carvalho de Melo <acme@...nel.org>
To: Ian Rogers <irogers@...gle.com>
Cc: Tony Jones <tonyj@...e.de>, Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...hat.com>, Namhyung Kim <namhyung@...nel.org>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
Jiri Olsa <jolsa@...nel.org>,
Adrian Hunter <adrian.hunter@...el.com>,
James Clark <james.clark@...aro.org>,
Howard Chu <howardchu95@...il.com>,
Stephen Brennan <stephen.s.brennan@...cle.com>,
linux-kernel@...r.kernel.org, linux-perf-users@...r.kernel.org
Subject: Re: [PATCH v3 2/7] perf addr2line: Add a libdw implementation
On Sat, Jan 10, 2026 at 08:13:33PM -0800, Ian Rogers wrote:
> Add an implementation of addr2line that uses libdw. Other addr2line
> implementations are slow, particularly in the case of forking
> addr2line. Add an implementation that caches the libdw information in
> the dso and uses it to find the file and line number
> information. Inline information is supported but because
> cu_walk_functions_at visits the leaf function last add a
> inline_list__append_tail to reverse the lists order.
So while testing I moved the inlineloop 'perf test' workload to the
front to test without this new libdw implementation and then with it,
and tested using perf probe on it:
root@...ber:/home/acme# perf probe -x ~/bin/perf libdw__addr2line%return 'ret=$retval'
Added new event:
probe_perf:libdw_addr2line__return (on libdw__addr2line%return in /home/acme/bin/perf with ret=$retval)
You can now use it in all perf tools, such as:
perf record -e probe_perf:libdw_addr2line__return -aR sleep 1
root@...ber:/home/acme# perf trace -e probe_perf:libdw_addr2line__return perf report -f --dso perf --stdio -s srcfile,srcline
0.000 :1204769/1204769 probe_perf:libdw_addr2line__return(__probe_func: 7698362, __probe_ret_ip: 7030548, ret: 1)
0.007 :1204769/1204769 probe_perf:libdw_addr2line__return(__probe_func: 7698362, __probe_ret_ip: 7030548)
0.680 perf/1204769 probe_perf:libdw_addr2line__return(__probe_func: 7698362, __probe_ret_ip: 7030548)
0.685 perf/1204769 probe_perf:libdw_addr2line__return(__probe_func: 7698362, __probe_ret_ip: 7030548)
0.689 perf/1204769 probe_perf:libdw_addr2line__return(__probe_func: 7698362, __probe_ret_ip: 7030548)
0.692 perf/1204769 probe_perf:libdw_addr2line__return(__probe_func: 7698362, __probe_ret_ip: 7030548)
0.696 perf/1204769 probe_perf:libdw_addr2line__return(__probe_func: 7698362, __probe_ret_ip: 7030548)
0.699 perf/1204769 probe_perf:libdw_addr2line__return(__probe_func: 7698362, __probe_ret_ip: 7030548)
0.702 perf/1204769 probe_perf:libdw_addr2line__return(__probe_func: 7698362, __probe_ret_ip: 7030548)
0.705 perf/1204769 probe_perf:libdw_addr2line__return(__probe_func: 7698362, __probe_ret_ip: 7030548)
0.709 perf/1204769 probe_perf:libdw_addr2line__return(__probe_func: 7698362, __probe_ret_ip: 7030548)
0.712 perf/1204769 probe_perf:libdw_addr2line__return(__probe_func: 7698362, __probe_ret_ip: 7030548)
0.715 perf/1204769 probe_perf:libdw_addr2line__return(__probe_func: 7698362, __probe_ret_ip: 7030548)
0.718 perf/1204769 probe_perf:libdw_addr2line__return(__probe_func: 7698362, __probe_ret_ip: 7030548)
0.721 perf/1204769 probe_perf:libdw_addr2line__return(__probe_func: 7698362, __probe_ret_ip: 7030548)
0.724 perf/1204769 probe_perf:libdw_addr2line__return(__probe_func: 7698362, __probe_ret_ip: 7030548)
0.727 perf/1204769 probe_perf:libdw_addr2line__return(__probe_func: 7698362, __probe_ret_ip: 7030548)
0.729 perf/1204769 probe_perf:libdw_addr2line__return(__probe_func: 7698362, __probe_ret_ip: 7030548)
0.732 perf/1204769 probe_perf:libdw_addr2line__return(__probe_func: 7698362, __probe_ret_ip: 7030548)
0.734 perf/1204769 probe_perf:libdw_addr2line__return(__probe_func: 7698362, __probe_ret_ip: 7030548)
0.737 perf/1204769 probe_perf:libdw_addr2line__return(__probe_func: 7698362, __probe_ret_ip: 7030548)
0.740 perf/1204769 probe_perf:libdw_addr2line__return(__probe_func: 7698362, __probe_ret_ip: 7030548)
0.771 perf/1204769 probe_perf:libdw_addr2line__return(__probe_func: 7698362, __probe_ret_ip: 7030548, ret: 1)
13.563 perf/1204769 probe_perf:libdw_addr2line__return(__probe_func: 7698362, __probe_ret_ip: 7030548, ret: 1)
13.766 perf/1204769 probe_perf:libdw_addr2line__return(__probe_func: 7698362, __probe_ret_ip: 7030548)
14.099 perf/1204769 probe_perf:libdw_addr2line__return(__probe_func: 7698362, __probe_ret_ip: 7030548)
14.103 perf/1204769 probe_perf:libdw_addr2line__return(__probe_func: 7698362, __probe_ret_ip: 7030548, ret: 1)
14.105 perf/1204769 probe_perf:libdw_addr2line__return(__probe_func: 7698362, __probe_ret_ip: 7030548, ret: 1)
14.134 perf/1204769 probe_perf:libdw_addr2line__return(__probe_func: 7698362, __probe_ret_ip: 7030548, ret: 1)
14.143 perf/1204769 probe_perf:libdw_addr2line__return(__probe_func: 7698362, __probe_ret_ip: 7030548, ret: 1)
14.242 perf/1204769 probe_perf:libdw_addr2line__return(__probe_func: 7698362, __probe_ret_ip: 7030548, ret: 1)
14.244 perf/1204769 probe_perf:libdw_addr2line__return(__probe_func: 7698362, __probe_ret_ip: 7030548, ret: 1)
14.245 perf/1204769 probe_perf:libdw_addr2line__return(__probe_func: 7698362, __probe_ret_ip: 7030548, ret: 1)
14.246 perf/1204769 probe_perf:libdw_addr2line__return(__probe_func: 7698362, __probe_ret_ip: 7030548, ret: 1)
14.248 perf/1204769 probe_perf:libdw_addr2line__return(__probe_func: 7698362, __probe_ret_ip: 7030548, ret: 1)
14.250 perf/1204769 probe_perf:libdw_addr2line__return(__probe_func: 7698362, __probe_ret_ip: 7030548, ret: 1)
14.251 perf/1204769 probe_perf:libdw_addr2line__return(__probe_func: 7698362, __probe_ret_ip: 7030548, ret: 1)
14.252 perf/1204769 probe_perf:libdw_addr2line__return(__probe_func: 7698362, __probe_ret_ip: 7030548, ret: 1)
14.258 perf/1204769 probe_perf:libdw_addr2line__return(__probe_func: 7698362, __probe_ret_ip: 7030548, ret: 1)
14.260 perf/1204769 probe_perf:libdw_addr2line__return(__probe_func: 7698362, __probe_ret_ip: 7030548, ret: 1)
14.265 perf/1204769 probe_perf:libdw_addr2line__return(__probe_func: 7698362, __probe_ret_ip: 7030548, ret: 1)
14.267 perf/1204769 probe_perf:libdw_addr2line__return(__probe_func: 7698362, __probe_ret_ip: 7030548, ret: 1)
14.268 perf/1204769 probe_perf:libdw_addr2line__return(__probe_func: 7698362, __probe_ret_ip: 7030548, ret: 1)
14.270 perf/1204769 probe_perf:libdw_addr2line__return(__probe_func: 7698362, __probe_ret_ip: 7030548, ret: 1)
# To display the perf.data header info, please use --header/--header-only options.
#
#
# Total Lost Samples: 0
#
# Samples: 4K of event 'cpu/cycles/Pu'
# Event count (approx.): 5535180842
#
# Overhead Source File Source:Line
# ........ ............ ...............
#
99.04% inlineloop.c inlineloop.c:21
0.46% inlineloop.c inlineloop.c:20
#
# (Tip: Save output of perf stat using: perf stat record <target workload>)
#
root@...ber:/home/acme#
Putting more probes to see the fallbacks...
root@...ber:/home/acme# perf probe -l
probe_perf:cmd_addr2line (on cmd__addr2line@...l/addr2line.c in /home/acme/bin/perf)
probe_perf:libbfd_addr2line (on libbfd__addr2line@...l/libbfd.h in /home/acme/bin/perf)
probe_perf:libdw_addr2line (on libdw__addr2line@...l/libdw.c in /home/acme/bin/perf)
probe_perf:llvm_addr2line (on llvm__addr2line@...l/llvm.c in /home/acme/bin/perf)
probe_perf:libdw_addr2line__return (on libdw__addr2line%return@...l/libdw.c in /home/acme/bin/perf with ret)
root@...ber:/home/acme#
As we have:
static int addr2line(const char *dso_name, u64 addr, char **file, unsigned int *line_nr,
struct dso *dso, bool unwind_inlines, struct inline_node *node,
struct symbol *sym)
{
int ret;
ret = libdw__addr2line(dso_name, addr, file, line_nr, dso, unwind_inlines, node, sym);
if (ret > 0)
return ret;
ret = llvm__addr2line(dso_name, addr, file, line_nr, dso, unwind_inlines, node, sym);
if (ret > 0)
return ret;
ret = libbfd__addr2line(dso_name, addr, file, line_nr, dso, unwind_inlines, node, sym);
if (ret > 0)
return ret;
return cmd__addr2line(dso_name, addr, file, line_nr, dso, unwind_inlines, node, sym);
}
root@...ber:/home/acme# perf stat -e probe_perf:*_addr2line perf report -f --dso perf --stdio -s srcfile,srcline
# To display the perf.data header info, please use --header/--header-only options.
#
#
# Total Lost Samples: 0
#
# Samples: 4K of event 'cpu/cycles/Pu'
# Event count (approx.): 5535180842
#
# Overhead Source File Source:Line
# ........ ............ ...............
#
99.04% inlineloop.c inlineloop.c:21
0.46% inlineloop.c inlineloop.c:20
#
# (Tip: To set sampling period of individual events use perf record -e cpu/cpu-cycles,period=100001/,cpu/branches,period=10001/ ...)
#
Performance counter stats for 'perf report -f --dso perf --stdio -s srcfile,srcline':
44 probe_perf:libdw_addr2line
23 probe_perf:llvm_addr2line
0 probe_perf:libbfd_addr2line
0 probe_perf:cmd_addr2line
0.036554827 seconds time elapsed
0.030570000 seconds user
0.006049000 seconds sys
root@...ber:/home/acme#
Maybe asking for the dso_name may help understand why it is falling back
23 times to the llvm based one...
root@...ber:/home/acme# perf probe -x ~/bin/perf llvm__addr2line dso_name:string
Target program is compiled without optimization. Skipping prologue.
Probe on address 0x5f73e4 to force probing at the function entry.
Added new event:
probe_perf:llvm_addr2line (on llvm__addr2line in /home/acme/bin/perf with dso_name:string)
You can now use it in all perf tools, such as:
perf record -e probe_perf:llvm_addr2line -aR sleep 1
root@...ber:/home/acme# perf trace --libtrace -e probe_perf:llvm_addr2line perf report -f --dso perf --stdio -s srcfile,srcline
0.000 perf/1205478 probe_perf:llvm_addr2line((5f7416) dso_name_string="/root/.debug/.build-id/cc/315df11334de01fb444465f08f6bca45a12bd2/elf")
0.697 perf/1205478 probe_perf:llvm_addr2line((5f7416) dso_name_string="/root/.debug/.build-id/cc/315df11334de01fb444465f08f6bca45a12bd2/elf")
0.704 perf/1205478 probe_perf:llvm_addr2line((5f7416) dso_name_string="/root/.debug/.build-id/cc/315df11334de01fb444465f08f6bca45a12bd2/elf")
0.708 perf/1205478 probe_perf:llvm_addr2line((5f7416) dso_name_string="/root/.debug/.build-id/cc/315df11334de01fb444465f08f6bca45a12bd2/elf")
0.712 perf/1205478 probe_perf:llvm_addr2line((5f7416) dso_name_string="/root/.debug/.build-id/cc/315df11334de01fb444465f08f6bca45a12bd2/elf")
<SNIP>
root@...ber:/home/acme# readelf -wi /root/.debug/.build-id/cc/315df11334de01fb444465f08f6bca45a12bd2/elf | head -30
Contents of the .debug_info section:
Compilation Unit @ offset 0:
Length: 0x20 (32-bit)
Version: 5
Unit Type: DW_UT_partial (3)
Abbrev Offset: 0xad87
Pointer Size: 8
<0><c>: Abbrev Number: 38 (DW_TAG_partial_unit)
<d> DW_AT_stmt_list : 0
<11> DW_AT_comp_dir : (indirect line string, offset: 0xc9c): /usr/src/debug/glibc-2.42-5.fc43.x86_64/elf
<1><15>: Abbrev Number: 57 (DW_TAG_base_type)
<16> DW_AT_byte_size : 8
<17> DW_AT_encoding : 7 (unsigned)
<18> DW_AT_name : (indirect string, offset: 0x9bf1): long unsigned int
<1><1c>: Abbrev Number: 57 (DW_TAG_base_type)
<1d> DW_AT_byte_size : 1
<1e> DW_AT_encoding : 6 (signed char)
<1f> DW_AT_name : (indirect string, offset: 0x7bab): char
<1><23>: Abbrev Number: 0
Compilation Unit @ offset 0x24:
Length: 0x20 (32-bit)
Version: 5
Unit Type: DW_UT_partial (3)
Abbrev Offset: 0xad87
Pointer Size: 8
<0><30>: Abbrev Number: 38 (DW_TAG_partial_unit)
<31> DW_AT_stmt_list : 0
<35> DW_AT_comp_dir : (indirect line string, offset: 0xc9c): /usr/src/debug/glibc-2.42-5.fc43.x86_64/elf
<1><39>: Abbrev Number: 57 (DW_TAG_base_type)
root@...ber:/home/acme#
Some partial unit glibc DWARF 5. I think we need some more libdw setup
to handle those?
But then we can merge what James already reviewed and go on from here,
right?
- Arnaldo
> Signed-off-by: Ian Rogers <irogers@...gle.com>
> ---
> tools/perf/util/Build | 1 +
> tools/perf/util/dso.c | 2 +
> tools/perf/util/dso.h | 11 +++
> tools/perf/util/libdw.c | 153 ++++++++++++++++++++++++++++++++++++++
> tools/perf/util/libdw.h | 60 +++++++++++++++
> tools/perf/util/srcline.c | 24 ++++++
> tools/perf/util/srcline.h | 1 +
> 7 files changed, 252 insertions(+)
> create mode 100644 tools/perf/util/libdw.c
> create mode 100644 tools/perf/util/libdw.h
>
> diff --git a/tools/perf/util/Build b/tools/perf/util/Build
> index 1c2a43e1dc68..2bed6274e248 100644
> --- a/tools/perf/util/Build
> +++ b/tools/perf/util/Build
> @@ -224,6 +224,7 @@ perf-util-$(CONFIG_LIBDW) += dwarf-regs-powerpc.o
> perf-util-$(CONFIG_LIBDW) += dwarf-regs-x86.o
> perf-util-$(CONFIG_LIBDW) += debuginfo.o
> perf-util-$(CONFIG_LIBDW) += annotate-data.o
> +perf-util-$(CONFIG_LIBDW) += libdw.o
>
> perf-util-$(CONFIG_LIBDW_DWARF_UNWIND) += unwind-libdw.o
> perf-util-$(CONFIG_LOCAL_LIBUNWIND) += unwind-libunwind-local.o
> diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c
> index 344e689567ee..06980844c014 100644
> --- a/tools/perf/util/dso.c
> +++ b/tools/perf/util/dso.c
> @@ -32,6 +32,7 @@
> #include "string2.h"
> #include "vdso.h"
> #include "annotate-data.h"
> +#include "libdw.h"
>
> static const char * const debuglink_paths[] = {
> "%.0s%s",
> @@ -1605,6 +1606,7 @@ void dso__delete(struct dso *dso)
> auxtrace_cache__free(RC_CHK_ACCESS(dso)->auxtrace_cache);
> dso_cache__free(dso);
> dso__free_a2l(dso);
> + dso__free_a2l_libdw(dso);
> dso__free_symsrc_filename(dso);
> nsinfo__zput(RC_CHK_ACCESS(dso)->nsinfo);
> mutex_destroy(dso__lock(dso));
> diff --git a/tools/perf/util/dso.h b/tools/perf/util/dso.h
> index f8ccb9816b89..4aee23775054 100644
> --- a/tools/perf/util/dso.h
> +++ b/tools/perf/util/dso.h
> @@ -268,6 +268,7 @@ DECLARE_RC_STRUCT(dso) {
> const char *short_name;
> const char *long_name;
> void *a2l;
> + void *a2l_libdw;
> char *symsrc_filename;
> #if defined(__powerpc__)
> void *dwfl; /* DWARF debug info */
> @@ -334,6 +335,16 @@ static inline void dso__set_a2l(struct dso *dso, void *val)
> RC_CHK_ACCESS(dso)->a2l = val;
> }
>
> +static inline void *dso__a2l_libdw(const struct dso *dso)
> +{
> + return RC_CHK_ACCESS(dso)->a2l_libdw;
> +}
> +
> +static inline void dso__set_a2l_libdw(struct dso *dso, void *val)
> +{
> + RC_CHK_ACCESS(dso)->a2l_libdw = val;
> +}
> +
> static inline unsigned int dso__a2l_fails(const struct dso *dso)
> {
> return RC_CHK_ACCESS(dso)->a2l_fails;
> diff --git a/tools/perf/util/libdw.c b/tools/perf/util/libdw.c
> new file mode 100644
> index 000000000000..e4bfd52bd172
> --- /dev/null
> +++ b/tools/perf/util/libdw.c
> @@ -0,0 +1,153 @@
> +// SPDX-License-Identifier: GPL-2.0
> +#include "dso.h"
> +#include "libdw.h"
> +#include "srcline.h"
> +#include "symbol.h"
> +#include "dwarf-aux.h"
> +#include <fcntl.h>
> +#include <unistd.h>
> +#include <elfutils/libdwfl.h>
> +
> +void dso__free_a2l_libdw(struct dso *dso)
> +{
> + Dwfl *dwfl = dso__a2l_libdw(dso);
> +
> + if (dwfl) {
> + dwfl_end(dwfl);
> + dso__set_a2l_libdw(dso, NULL);
> + }
> +}
> +
> +struct libdw_a2l_cb_args {
> + struct dso *dso;
> + struct symbol *sym;
> + struct inline_node *node;
> + char *leaf_srcline;
> + bool leaf_srcline_used;
> +};
> +
> +static int libdw_a2l_cb(Dwarf_Die *die, void *_args)
> +{
> + struct libdw_a2l_cb_args *args = _args;
> + struct symbol *inline_sym = new_inline_sym(args->dso, args->sym, dwarf_diename(die));
> + const char *call_fname = die_get_call_file(die);
> + char *call_srcline = srcline__unknown;
> + struct inline_list *ilist;
> +
> + if (!inline_sym)
> + return -ENOMEM;
> +
> + /* Assign caller information to the parent. */
> + if (call_fname)
> + call_srcline = srcline_from_fileline(call_fname, die_get_call_lineno(die));
> +
> + list_for_each_entry(ilist, &args->node->val, list) {
> + ilist->srcline = call_srcline;
> + call_srcline = NULL;
> + break;
> + }
> + if (call_srcline && call_fname)
> + free(call_srcline);
> +
> + /* Add this symbol to the chain as the leaf. */
> + inline_list__append_tail(inline_sym, args->leaf_srcline, args->node);
> + args->leaf_srcline_used = true;
> + return 0;
> +}
> +
> +int libdw__addr2line(const char *dso_name, u64 addr,
> + char **file, unsigned int *line_nr,
> + struct dso *dso, bool unwind_inlines,
> + struct inline_node *node, struct symbol *sym)
> +{
> + static const Dwfl_Callbacks offline_callbacks = {
> + .find_debuginfo = dwfl_standard_find_debuginfo,
> + .section_address = dwfl_offline_section_address,
> + .find_elf = dwfl_build_id_find_elf,
> + };
> + Dwfl *dwfl = dso__a2l_libdw(dso);
> + Dwfl_Module *mod;
> + Dwfl_Line *dwline;
> + Dwarf_Addr bias;
> + const char *src;
> + int lineno = 0;
> +
> + if (!dwfl) {
> + /*
> + * Initialize Dwfl session.
> + * We need to open the DSO file to report it to libdw.
> + */
> + int fd;
> +
> + fd = open(dso_name, O_RDONLY);
> + if (fd < 0)
> + return 0;
> +
> + dwfl = dwfl_begin(&offline_callbacks);
> + if (!dwfl) {
> + close(fd);
> + return 0;
> + }
> +
> + /*
> + * If the report is successful, the file descriptor fd is consumed
> + * and closed by the Dwfl. If not, it is not closed.
> + */
> + mod = dwfl_report_offline(dwfl, dso_name, dso_name, fd);
> + if (!mod) {
> + dwfl_end(dwfl);
> + close(fd);
> + return 0;
> + }
> +
> + dwfl_report_end(dwfl, /*removed=*/NULL, /*arg=*/NULL);
> + dso__set_a2l_libdw(dso, dwfl);
> + } else {
> + /* Dwfl session already initialized, get module for address. */
> + mod = dwfl_addrmodule(dwfl, addr);
> + }
> +
> + if (!mod)
> + return 0;
> +
> + /*
> + * Get/ignore the dwarf information. Determine the bias, difference
> + * between the regular ELF addr2line addresses and those to use with
> + * libdw.
> + */
> + if (!dwfl_module_getdwarf(mod, &bias))
> + return 0;
> +
> + /* Find source line information for the address. */
> + dwline = dwfl_module_getsrc(mod, addr + bias);
> + if (!dwline)
> + return 0;
> +
> + /* Get line information. */
> + src = dwfl_lineinfo(dwline, /*addr=*/NULL, &lineno, /*col=*/NULL, /*mtime=*/NULL,
> + /*length=*/NULL);
> +
> + if (file)
> + *file = src ? strdup(src) : NULL;
> + if (line_nr)
> + *line_nr = lineno;
> +
> + /* Optionally unwind inline function call chain. */
> + if (unwind_inlines && node) {
> + Dwarf_Addr unused_bias;
> + Dwarf_Die *cudie = dwfl_module_addrdie(mod, addr + bias, &unused_bias);
> + struct libdw_a2l_cb_args args = {
> + .dso = dso,
> + .sym = sym,
> + .node = node,
> + .leaf_srcline = srcline_from_fileline(src ?: "<unknown>", lineno),
> + };
> +
> + /* Walk from the parent down to the leaf. */
> + cu_walk_functions_at(cudie, addr, libdw_a2l_cb, &args);
> +
> + if (!args.leaf_srcline_used)
> + free(args.leaf_srcline);
> + }
> + return 1;
> +}
> diff --git a/tools/perf/util/libdw.h b/tools/perf/util/libdw.h
> new file mode 100644
> index 000000000000..0f8d7b4a11a5
> --- /dev/null
> +++ b/tools/perf/util/libdw.h
> @@ -0,0 +1,60 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +#ifndef PERF_LIBDW_H
> +#define PERF_LIBDW_H
> +
> +#include <linux/types.h>
> +
> +struct dso;
> +struct inline_node;
> +struct symbol;
> +
> +#ifdef HAVE_LIBDW_SUPPORT
> +/*
> + * libdw__addr2line - Convert address to source location using libdw
> + * @dso_name: Name of the DSO
> + * @addr: Address to resolve
> + * @file: Pointer to return filename (caller must free)
> + * @line_nr: Pointer to return line number
> + * @dso: The dso struct
> + * @unwind_inlines: Whether to unwind inline function calls
> + * @node: Inline node list to append to
> + * @sym: The symbol associated with the address
> + *
> + * This function initializes a Dwfl context for the DSO if not already present,
> + * finds the source line information for the given address, and optionally
> + * resolves inline function call chains.
> + *
> + * Returns 1 on success (found), 0 on failure (not found).
> + */
> +int libdw__addr2line(const char *dso_name, u64 addr, char **file,
> + unsigned int *line_nr, struct dso *dso,
> + bool unwind_inlines, struct inline_node *node,
> + struct symbol *sym);
> +
> +/*
> + * dso__free_a2l_libdw - Free libdw resources associated with the DSO
> + * @dso: The dso to free resources for
> + *
> + * This function cleans up the Dwfl context used for addr2line lookups.
> + */
> +void dso__free_a2l_libdw(struct dso *dso);
> +
> +#else /* HAVE_LIBDW_SUPPORT */
> +
> +static inline int libdw__addr2line(const char *dso_name __maybe_unused,
> + u64 addr __maybe_unused, char **file __maybe_unused,
> + unsigned int *line_nr __maybe_unused,
> + struct dso *dso __maybe_unused,
> + bool unwind_inlines __maybe_unused,
> + struct inline_node *node __maybe_unused,
> + struct symbol *sym __maybe_unused)
> +{
> + return 0;
> +}
> +
> +static inline void dso__free_a2l_libdw(struct dso *dso __maybe_unused)
> +{
> +}
> +#endif /* HAVE_LIBDW_SUPPORT */
> +
> +#endif /* PERF_LIBDW_H */
> diff --git a/tools/perf/util/srcline.c b/tools/perf/util/srcline.c
> index 27c0966611ab..e2d280678b02 100644
> --- a/tools/perf/util/srcline.c
> +++ b/tools/perf/util/srcline.c
> @@ -6,6 +6,7 @@
> #include "libbfd.h"
> #include "llvm.h"
> #include "symbol.h"
> +#include "libdw.h"
>
> #include <inttypes.h>
> #include <string.h>
> @@ -51,6 +52,25 @@ int inline_list__append(struct symbol *symbol, char *srcline, struct inline_node
> return 0;
> }
>
> +int inline_list__append_tail(struct symbol *symbol, char *srcline, struct inline_node *node)
> +{
> + struct inline_list *ilist;
> +
> + ilist = zalloc(sizeof(*ilist));
> + if (ilist == NULL)
> + return -1;
> +
> + ilist->symbol = symbol;
> + ilist->srcline = srcline;
> +
> + if (callchain_param.order == ORDER_CALLEE)
> + list_add(&ilist->list, &node->val);
> + else
> + list_add_tail(&ilist->list, &node->val);
> +
> + return 0;
> +}
> +
> /* basename version that takes a const input string */
> static const char *gnu_basename(const char *path)
> {
> @@ -120,6 +140,10 @@ static int addr2line(const char *dso_name, u64 addr, char **file, unsigned int *
> {
> int ret;
>
> + ret = libdw__addr2line(dso_name, addr, file, line_nr, dso, unwind_inlines, node, sym);
> + if (ret > 0)
> + return ret;
> +
> ret = llvm__addr2line(dso_name, addr, file, line_nr, dso, unwind_inlines, node, sym);
> if (ret > 0)
> return ret;
> diff --git a/tools/perf/util/srcline.h b/tools/perf/util/srcline.h
> index c36f573cd339..be9f002bf234 100644
> --- a/tools/perf/util/srcline.h
> +++ b/tools/perf/util/srcline.h
> @@ -57,6 +57,7 @@ struct inline_node *inlines__tree_find(struct rb_root_cached *tree, u64 addr);
> void inlines__tree_delete(struct rb_root_cached *tree);
>
> int inline_list__append(struct symbol *symbol, char *srcline, struct inline_node *node);
> +int inline_list__append_tail(struct symbol *symbol, char *srcline, struct inline_node *node);
> char *srcline_from_fileline(const char *file, unsigned int line);
> struct symbol *new_inline_sym(struct dso *dso,
> struct symbol *base_sym,
> --
> 2.52.0.457.g6b5491de43-goog
>
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