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Message-ID: <1136b408-7bf8-4cc8-98b6-e44c2ed45aaf@linaro.org>
Date: Fri, 28 Nov 2025 14:25:46 +0000
From: James Clark <james.clark@...aro.org>
To: Ian Rogers <irogers@...gle.com>
Cc: Namhyung Kim <namhyung@...nel.org>, Tony Jones <tonyj@...e.de>,
Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>,
Arnaldo Carvalho de Melo <acme@...nel.org>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
Jiri Olsa <jolsa@...nel.org>, Adrian Hunter <adrian.hunter@...el.com>,
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 v1] perf addr2line: Add a libdw implementation
On 28/11/2025 9:00 am, Ian Rogers wrote:
> On Thu, Nov 27, 2025 at 5:48 AM James Clark <james.clark@...aro.org> wrote:
>>
>>
>>
>> On 27/11/2025 1:19 pm, Ian Rogers wrote:
>>> On Thu, Nov 27, 2025 at 4:16 AM James Clark <james.clark@...aro.org> wrote:
>>>>
>>>>
>>>>
>>>> On 27/11/2025 11:43 am, Ian Rogers wrote:
>>>>> On Wed, Nov 26, 2025 at 10:27 AM Namhyung Kim <namhyung@...nel.org> wrote:
>>>>>>
>>>>>> On Sat, Nov 22, 2025 at 01:39:34AM -0800, Ian Rogers wrote:
>>>>>>> Add an implementation of addr2line that uses libdw. Other addr2line
>>>>>>> implementations or, in the case of forking addr2line, slow. Add an
>>>>>>> implementation that caches the libdw information in the dso and uses
>>>>>>> it to find the file and line number information.
>>>>>
>>>>> Thanks James and Namhyung for the reviews! I agree with James' comment
>>>>> about a typo in the commit message.
>>>>>
>>>>>> My concern is the limit in the open file descriptors in case the data
>>>>>> touched a lot of different libraries. The DSO code has some logic to
>>>>>> deal with it but I'm not sure if we can share that since libdw seems to
>>>>>> want to own the FD.
>>>>>
>>>>> The code opens the FD:
>>>>>
>>>>> + fd = open(dso_name, O_RDONLY);
>>>>> + if (fd < 0)
>>>>> + return 0;
>>>>> +
>>>>> + dwfl = dwfl_begin(&offline_callbacks);
>>>>> + if (!dwfl) {
>>>>> + close(fd);
>>>>> + return 0;
>>>>> + }
>>>>>
>>>>> It then uses the FD and closes it (the close is hidden in libdw itself):
>>>>>
>>>>> + /*
>>>>> + * 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);
>>>>>
>>>>> So it is possible we exhaust all the file descriptors if there are
>>>>> multiple concurrent calls to libdw__addr2line and every dso has
>>>>> missing libdw dwfl data... but because the open/close are close
>>>>> together and that 1 FD is say small to the FDs needed for the
>>>>> cmd__addr2line, I don't think it is a problem we need to specifically
>>>>> handle. Were the FD kept open until the dso was deleted, I'd agree
>>>>> with you.
>>>>>
>>>>>> Also, have you checked if this generates the exactly same output with
>>>>>> other implementations?
>>>>>
>>>>> So the code passes `perf test` and I was checking functionality with
>>>>> perf annotate, top, etc. What I saw looked good, but it may not have
>>>>> been exhaustive. I didn't specifically create a test that compares the
>>>>> output of the different addr2line implementations. Such a test would
>>>>> be possible, it's not something we've done elsewhere.
>>>>>
>>>>> Thanks,
>>>>> Ian
>>>>>
>>>>
>>>> I manually looked at a couple of line numbers and they looked
>>>> reasonable. I think an automated test that compared dwarf decoders would
>>>> be a bit of a nightmare because I'm sure there would always be subtle
>>>> differences.
>>>>
>>>> Doing a manual side by side comparison of libdw__addr2line() and
>>>> llvm__addr2line(), they seem to be quite different:
>>>>
>>>> $ perf record -- perf test -w leafloop
>>>> $ perf script -F ip,srcline > libdw_addr2line.txt
>>>> # Comment out libdw_addr2line() and rebuild
>>>> $ perf script -F ip,srcline > llvm_addr2line.txt
>>>> $ diff libdw_addr2line.txt llvm_addr2line.txt
>>>>
>>>> It gets all of the simple leafloop workload lines the same, but lots of
>>>> the libc stuff is different.
>>>>
>>>> For example libdw gives cpu-features.c:350 where llvm gives strcmp.S. At
>>>> least that one looks like inlining so llvm might be "better", but where
>>>> it gives dl-cache.c:490 isntead of llvm's mmap64.c:47, it's hard to see
>>>> how that can be inlining if they're in different compilation units.
>>>>
>>>> If the llvm addr2line implementation is also supposed to be slow, it
>>>> just means we're trading speed with accuracy with this change. Hard to
>>>> say what the default should be in that case.
>>>
>>> Agreed. We could do some kind of option scheme like with the disassemblers:
>>> https://web.git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools-next.git/tree/tools/perf/util/disasm.c?h=perf-tools-next#n1715
>>>
>>> I'm not sure there are currently any distributions using the LLVM
>>> options, this in part motivates:
>>> https://lore.kernel.org/lkml/20251007163835.3152881-1-irogers@google.com/
>>> but the addr2line APIs are a pain there - see the extra generated .so.
>>> Because of that it could be reasonable to delete the LLVM addr2line
>>> code and just focus on libdw. I kind of wish we could also delete the
>>> precarious command forking versions too. And libbfd... Perhaps with
>>> this code, those advocating libbfd have a fast enough alternative
>>> without bringing in large dependencies like libLLVM.
>>>
>>> Thanks,
>>> Ian
>>>
>>
>> Personally for debugging I would want the most accurate and detailed
>> information possible and don't care at all about the size of
>> dependencies. If Perf is a tool for debugging then surely that should be
>> the default? But right now I don't actually know which of the outputs is
>> most accurate although I'll assume that the llvm one is.
>
> I know LLVM got dwarf 5 support early. I'm not sure if accurate is the
> best word to compare libdw and LLVM as, if libdw supports the format,
> discrepancies are bugs in LLVM or libdw, .. Building around LLVM as a
> common base sgtm and my main use-case doesn't get impeded by the large
> dependency because of the dlopen patches. As libelf/libdw is pretty
> much a given for a perf build, as it is required for libbpf, then the
> code here can avoid the fork/exec fallback. I can see the sense in
> trying with LLVM first and then falling back to libdw.
>
Seems like my libc does have dwarf 5 symbols. Looking a bit more I still
think "accurate" is the right word. Comparing gdb, forked addr2line and
llvm_addr2line(), all 3 agree on the source line for every address in my
recording. The only one that disagrees is libdw_addr2line(). I don't
know if there's an issue with how it's being called, or there is a bug
in the library.
Digging even deeper, if I put breakpoints on the lines that
libdw_addr2line() gives, they aren't even hit. So it's not even like
it's not de-inlining stuff, which you could argue is fine. And there is
the issue that some of the results are in completely different C files.
It's hard to see why it's giving such different results without
debugging libdw line by line.
I'm not sure if you see the same thing with a simple recording or you
want me to send a perf archive?
>> Wanting the smallest application possible while trading away detail and
>> accuracy seems like an unusual special case that should be opt in. It
>> also seems to relate to this old discussion [1], in that if we're going
>> to keep the llvm depencency then it doesn't make sense to re-write
>> anything in Perf.
>
> So I think PE support in libdw wouldn't be a priority and so LLVM for
> the win there. I think distributions have been slow to pick up the
> LLVM dependency, I'm not sure what the issue is there. It would be
> nice to start removing some of the alternatives the perf build
> supports. The libbfd and libunwind code is only built with specific
> opt-ins, and I think the fork/exec addr2line is redundant after this
> change. For addr2line that'd bring the 2 implementations down to libdw
It might be a bit premature to drop the addr2line fork if libdw isn't
mature enough. Especially as it seems to fall over on such a basic test.
Hopefully it's just an issue with how it's called or the version that I
have.
> and LLVM. As the recent libbfd fixes show [1], inadvertently we can
> break these largely untested dependencies by exposing latent bugs in
> things like improper initialization.
>
> Thanks,
> Ian
>
> [1] https://lore.kernel.org/lkml/20251112074311.1440101-1-irogers@google.com/
>
>> [1]:
>> https://lore.kernel.org/linux-perf-users/549d3812-a606-4981-83f5-0a99b0ff9f6a@linaro.org/
>>
>>>>>> Thanks,
>>>>>> Namhyung
>>>>>>
>>>>>>>
>>>>>>> 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 | 136 ++++++++++++++++++++++++++++++++++++++
>>>>>>> tools/perf/util/libdw.h | 60 +++++++++++++++++
>>>>>>> tools/perf/util/srcline.c | 5 ++
>>>>>>> 6 files changed, 215 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..c4331fa8e1a3
>>>>>>> --- /dev/null
>>>>>>> +++ b/tools/perf/util/libdw.c
>>>>>>> @@ -0,0 +1,136 @@
>>>>>>> +// 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);
>>>>>>> + }
>>>>>>> +}
>>>>>>> +
>>>>>>> +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;
>>>>>>> +
>>>>>>> + 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;
>>>>>>> +
>>>>>>> + /* Find source line information for the address. */
>>>>>>> + dwline = dwfl_module_getsrc(mod, addr);
>>>>>>> + if (!dwline)
>>>>>>> + return 0;
>>>>>>> +
>>>>>>> + /* Get line information. */
>>>>>>> + src = dwfl_lineinfo(dwline, &addr, &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 && src) {
>>>>>>> + Dwarf_Die *cudie = dwfl_module_addrdie(mod, addr, &bias);
>>>>>>> + Dwarf_Die *scopes = NULL;
>>>>>>> + int nscopes;
>>>>>>> +
>>>>>>> + if (!cudie)
>>>>>>> + return 1;
>>>>>>> +
>>>>>>> + nscopes = die_get_scopes(cudie, addr, &scopes);
>>>>>>> + if (nscopes > 0) {
>>>>>>> + int i;
>>>>>>> + const char *call_file = src;
>>>>>>> + unsigned int call_line = lineno;
>>>>>>> +
>>>>>>> + for (i = 0; i < nscopes; i++) {
>>>>>>> + Dwarf_Die *die = &scopes[i];
>>>>>>> + struct symbol *inline_sym;
>>>>>>> + char *srcline = NULL;
>>>>>>> + int tag = dwarf_tag(die);
>>>>>>> +
>>>>>>> + /* We are interested in inlined subroutines. */
>>>>>>> + if (tag != DW_TAG_inlined_subroutine &&
>>>>>>> + tag != DW_TAG_subprogram)
>>>>>>> + continue;
>>>>>>> +
>>>>>>> + inline_sym = new_inline_sym(dso, sym, dwarf_diename(die));
>>>>>>> +
>>>>>>> + if (call_file)
>>>>>>> + srcline = srcline_from_fileline(call_file, call_line);
>>>>>>> +
>>>>>>> + inline_list__append(inline_sym, srcline, node);
>>>>>>> +
>>>>>>> + /* Update call site for next level. */
>>>>>>> + if (tag == DW_TAG_inlined_subroutine) {
>>>>>>> + call_file = die_get_call_file(die);
>>>>>>> + call_line = die_get_call_lineno(die);
>>>>>>> + } else {
>>>>>>> + /* Reached the root subprogram. */
>>>>>>> + break;
>>>>>>> + }
>>>>>>> + }
>>>>>>> + free(scopes);
>>>>>>> + }
>>>>>>> + }
>>>>>>> +
>>>>>>> + 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..4b456c4d4138 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>
>>>>>>> @@ -120,6 +121,10 @@ 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;
>>>>>>> --
>>>>>>> 2.52.0.rc2.455.g230fcf2819-goog
>>>>>>>
>>>>
>>
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