On 10/05/16 14:38, Hekuang wrote: > > > 在 2016/5/10 18:34, Adrian Hunter 写道: >> On 10/05/16 12:49, Hekuang wrote: >>> hi >>> >>> 在 2016/5/10 16:08, Adrian Hunter 写道: >>>> On 10/05/16 10:40, He Kuang wrote: >>>>> 32-bit programs can be run on 64-bit machines, so we should choose >>>>> unwind methods according to 'thread->map' instead of the host >>>>> architecture. >>>>> >>>>> This patch adds methods to test whether a dso is 64-bit or 32-bit by >>>>> the class info in elf. >>>> What about using dso->is_64_bit set by dso__load_sym() ? >>> I've noticed this variable, but it's value is not as its name said: >>> >>> util/dso.c: 1067 dso->is_64_bit = (sizeof(void *) == 8); >> That is just initialization i.e. before we know what it is we assume it is >> the same as the host. >> >>> This is only related to the host architecture. >>> >>> A closer one is 'is_64_bit' in 'struct symsrc', but the value is assigned >>> after dso >>> loaded. So I think we should provide individual methods to get that value. >> Are you saying you don't load dsos? Or that is_64_bit is set incorrectly? >> > > Yes, I know it's the inital value, but the correct value is > assigned in function dso__load_sym(), and have a look at the call > stack(gdb): > > #0 dso__load_sym > #1 in dso__load > #2 in map__load > #3 in map__find_symbol > #4 in thread__find_addr_location > #5 in entry > #6 in get_entries > #7 in _Ux86__unwind__get_entries > #8 in thread__resolve_callchain > > I think we should choose the right unwind method before > dso__load_sym(). i.e. line#7, which is called before dso__load_sym(). > > I'm not very familiar with this, what's your opinion?
Have you considered calling map__load() instead of dso_is_64_bit()
