On Wed, Sep 04, 2013 at 08:04:14PM +0200, Jean Pihet wrote:
> On ARM the debug info is not present in the .eh_frame sections but
> instead in .debug_frame.
> Use libunwind to load and parse the debug info.
hum, cannot make final link:
$ make LIBUNWIND_DIR=/opt/libunwind/
CHK -fstack-protector-all
CHK -Wstack-protector
CHK -Wvolatile-register-var
CHK -D_FORTIFY_SOURCE=2
CHK bionic
CHK libelf
CHK libdw
CHK -DLIBELF_MMAP
CHK -DLIBELF_MMAP
CHK libunwind
CHK libaudit
...
make[1]: `liblk.a' is up to date.
SUBDIR /home/jolsa/linux-perf/tools/lib/traceevent/
LINK perf
libperf.a(unwind.o): In function `find_proc_info':
/home/jolsa/linux-perf/tools/perf/util/unwind.c:339: undefined reference to
`_Ux86_64_dwarf_find_debug_frame'
collect2: ld returned 1 exit status
make: *** [perf] Error 1
I'm using the latest code from git://git.sv.gnu.org/libunwind.git
Looks like dwarf_find_debug_frame is not exported, although
it looks like it is based on what I see in libunwind sources ;-)
What did I miss?
Also few typo comments below..
thanks,
jirka
>
> Signed-off-by: Jean Pihet <jean.pi...@linaro.org>
> ---
> tools/perf/util/unwind.c | 70
> +++++++++++++++++++++++++++++++++++++-----------
> 1 file changed, 54 insertions(+), 16 deletions(-)
>
> diff --git a/tools/perf/util/unwind.c b/tools/perf/util/unwind.c
> index 958723b..5353b32 100644
> --- a/tools/perf/util/unwind.c
> +++ b/tools/perf/util/unwind.c
> @@ -39,6 +39,14 @@ UNW_OBJ(dwarf_search_unwind_table) (unw_addr_space_t as,
>
> #define dwarf_search_unwind_table UNW_OBJ(dwarf_search_unwind_table)
>
> +extern int
> +UNW_OBJ(dwarf_find_debug_frame) (int found, unw_dyn_info_t *di_debug,
> + unw_word_t ip,
> unw_word_t segbase,
> + const char
> *obj_name, unw_word_t start,
> + unw_word_t
> end);
> +
> +#define dwarf_find_debug_frame UNW_OBJ(dwarf_find_debug_frame)
> +
> #define DW_EH_PE_FORMAT_MASK 0x0f /* format of the encoded value */
> #define DW_EH_PE_APPL_MASK 0x70 /* how the value is to be applied */
>
> @@ -245,8 +253,9 @@ static int unwind_spec_ehframe(struct dso *dso, struct
> machine *machine,
> return 0;
> }
>
> -static int read_unwind_spec(struct dso *dso, struct machine *machine,
> - u64 *table_data, u64 *segbase, u64 *fde_count)
> +static int read_unwind_spec_eh_frame(struct dso *dso, struct machine
> *machine,
> + u64 *table_data, u64 *segbase,
> + u64 *fde_count)
> {
> int ret = -EINVAL, fd;
> u64 offset;
> @@ -255,6 +264,7 @@ static int read_unwind_spec(struct dso *dso, struct
> machine *machine,
> if (fd < 0)
> return -EINVAL;
>
> + /* Check the .eh_frame section for unwinding info */
> offset = elf_section_offset(fd, ".eh_frame_hdr");
> close(fd);
>
> @@ -263,10 +273,27 @@ static int read_unwind_spec(struct dso *dso, struct
> machine *machine,
> table_data, segbase,
> fde_count);
>
> - /* TODO .debug_frame check if eh_frame_hdr fails */
> return ret;
> }
>
> +static int read_unwind_spec_debug_frame(struct dso *dso,
> +
> struct machine *machine, u64 *offset)
> +{
some strange formatting issue ^^^ ;-)
> + int fd = dso__data_fd(dso, machine);
> +
> + if (fd < 0)
> + return -EINVAL;
> +
> + /* Check the .debug_frame section for unwinding info */
> + *offset = elf_section_offset(fd, ".debug_frame");
> + close(fd);
> +
> + if (*offset)
> + return 0;
> +
> + return -EINVAL;
> +}
> +
> static struct map *find_map(unw_word_t ip, struct unwind_info *ui)
> {
> struct addr_location al;
> @@ -291,20 +318,31 @@ find_proc_info(unw_addr_space_t as, unw_word_t ip,
> unw_proc_info_t *pi,
>
> pr_debug("unwind: find_proc_info dso %s\n", map->dso->name);
>
> - if (read_unwind_spec(map->dso, ui->machine,
> - &table_data, &segbase, &fde_count))
> - return -EINVAL;
> + /* Check the .eh_frame section for unwinding info */
> + if (!read_unwind_spec_eh_frame(map->dso, ui->machine,
> + &table_data,
> &segbase, &fde_count)) {
ditto ^^^
> + memset(&di, 0, sizeof(di));
> + di.format = UNW_INFO_FORMAT_REMOTE_TABLE;
> + di.start_ip = map->start;
> + di.end_ip = map->end;
> + di.u.rti.segbase = map->start + segbase;
> + di.u.rti.table_data = map->start + table_data;
> + di.u.rti.table_len = fde_count * sizeof(struct table_entry)
> + / sizeof(unw_word_t);
> + return dwarf_search_unwind_table(as, ip, &di, pi,
> +
> need_unwind_info, arg);
ditto ^^^
> + }
> +
> + /* Check the .debug_frame section for unwinding info */
> + if (!read_unwind_spec_debug_frame(map->dso, ui->machine, &segbase)) {
> + memset(&di, 0, sizeof(di));
> + dwarf_find_debug_frame(0, &di, ip, 0, map->dso->name,
> + map->start,
> map->end);
> + return dwarf_search_unwind_table(as, ip, &di, pi,
> +
> need_unwind_info, arg);
ditto ^^^
> + }
>
> - memset(&di, 0, sizeof(di));
> - di.format = UNW_INFO_FORMAT_REMOTE_TABLE;
> - di.start_ip = map->start;
> - di.end_ip = map->end;
> - di.u.rti.segbase = map->start + segbase;
> - di.u.rti.table_data = map->start + table_data;
> - di.u.rti.table_len = fde_count * sizeof(struct table_entry)
> - / sizeof(unw_word_t);
> - return dwarf_search_unwind_table(as, ip, &di, pi,
> - need_unwind_info, arg);
> + return -EINVAL;
> }
>
> static int access_fpreg(unw_addr_space_t __maybe_unused as,
> --
> 1.7.11.7
>
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