http://sourceware.org/bugzilla/show_bug.cgi?id=15200
--- Comment #10 from Doug Kwan <dougkwan at google dot com> 2013-03-13 03:57:35 UTC --- I have no object to what is proposed but the decision is Ian's. On Tue, Mar 12, 2013 at 7:03 PM, petechou at gmail dot com <sourceware-bugzi...@sourceware.org> wrote: > http://sourceware.org/bugzilla/show_bug.cgi?id=15200 > > --- Comment #9 from pete <petechou at gmail dot com> 2013-03-13 02:03:32 UTC > --- > If there is a libfoo.so, it's possible to implement part of functions in > libfoo.so and then link against libfoo.so again to produce a new library. I > think the "linker-defined" symbols should also have higher priority than the > symbols in DSO. > > And I also think we should have the same behavior on defining symbol value > whether only_if_ref is set or not? > > The patch will affect 4 ways to define output symbols: > 1. do_define_in_output_data > 2. do_define_in_output_segment > 3. do_define_as_constant > 4. add_undefined_symbol_from_command_line > > For 1, 2, and 3, it makes sense to use the given output section, segment, and > constant to define symbol values if the "linker-defined" symbols have higher > priority. > > As for 4, I think it doesn't matter. > > - > Thanks, > Pete > > (In reply to comment #8) >> Hi Pete, >> >> 1. My concern of your patch is that it affects all targets, not just >> ARM. While it may fix the problem on ARM, I cannot speak for authors >> of other backends. >> 2. I am don't have power approve a patch, you need to convince Ian >> Taylor that this is the right thing to do for all targets. >> 3. This bug only happens when DSOs incorrectly export __exidx_start & >> __exidx_end. These DSOs are considered broken and I strongly >> recommend you moving to a newer NDK version with DSOs that have proper >> visibility. Both ld & gold no longer export these symbols. The >> reason for not exporting is explained here in the ld patch: >> >> http://sourceware.org/ml/binutils/2009-11/msg00367.html >> >> -Doug >> >> >> On Wed, Mar 6, 2013 at 10:43 PM, petechou at gmail dot com >> <sourceware-bugzi...@sourceware.org> wrote: >> > http://sourceware.org/bugzilla/show_bug.cgi?id=15200 >> > >> > --- Comment #7 from pete <petechou at gmail dot com> 2013-03-07 06:43:08 >> > UTC --- >> > I can think visibility does matter, but only for exporting the symbol or >> > not. >> > In the previous case, gold does define the __bss symbols but not use the >> > definition in DSO, so I think we should still define section/segment >> > symbols >> > locally. >> > >> > -Pete >> > >> > (In reply to comment #6) >> >> The symbols do not have same visibility. gold in general is >> >> compatible with GNU ld. If you look at src/ld/emulparams/, you will >> >> set that the __bss symbols are exported but the __exidx symbols are >> >> defined hidden. gold matches the behaviour of ld. If you look at >> >> defstd.cc in gold, you will again see that some of these symbols are >> >> hidden but some are not. >> >> >> >> -Doug >> >> >> >> >> >> On Wed, Mar 6, 2013 at 9:31 PM, petechou at gmail dot com >> >> <sourceware-bugzi...@sourceware.org> wrote: >> >> > http://sourceware.org/bugzilla/show_bug.cgi?id=15200 >> >> > >> >> > --- Comment #5 from pete <petechou at gmail dot com> 2013-03-07 >> >> > 05:31:25 UTC --- >> >> > (In reply to comment #4) >> >> >> The symbols __exidx_end & __exidx_start were exported incorrectly in >> >> >> the past. This is fixed in both ld & gold in the sense that these >> >> >> symbols are defined by not exported. I think defining these symbols >> >> >> when there is a non-weak definition in a DSO is not the right thing to >> >> >> do. This is basically multiple definition and usually is an error. >> >> > >> >> > If so, all section/segment symbols should be defined (if needed) by not >> >> > exported? >> >> > >> >> > But when there is a non-weak definition in a DSO, it's still possible >> >> > to find >> >> > ld.gold define and export segment symbols like __bss_start (See >> >> > gold.defstd.cc:214. only_if_ref is set to false). And there is no >> >> > multiple >> >> > definition error. >> >> > >> >> > $ readelf -Ds libc.so | grep __bss_start >> >> > 268 311: 0000d898 0 NOTYPE GLOBAL DEFAULT ABS __bss_start__ >> >> > 619 470: 0000d898 0 NOTYPE GLOBAL DEFAULT ABS __bss_start >> >> > >> >> > $ arm-linux-androideabi-ld.gold -shared -o libplasma.so plasma.o libc.so >> >> > >> >> > $ readelf -s libplasma.so | grep __bss_start >> >> > 73: 00004148 0 NOTYPE GLOBAL DEFAULT ABS __bss_start >> >> > 168: 00004148 0 NOTYPE GLOBAL DEFAULT ABS __bss_start >> >> > >> >> >> I am not working on the Android NDK so I can't give you a good >> >> >> suggestion here. Does using the latest NDK fixes your problem? >> >> >> >> >> > >> >> > Yes, there is no this issue with the latest NDK. >> >> > >> >> > - >> >> > Thanks, >> >> > Pete >> >> > >> >> > -- >> >> > Configure bugmail: >> >> > http://sourceware.org/bugzilla/userprefs.cgi?tab=email >> >> > ------- You are receiving this mail because: ------- >> >> > You are on the CC list for the bug. >> > >> > -- >> > Configure bugmail: http://sourceware.org/bugzilla/userprefs.cgi?tab=email >> > ------- You are receiving this mail because: ------- >> > You are on the CC list for the bug. > > -- > Configure bugmail: http://sourceware.org/bugzilla/userprefs.cgi?tab=email > ------- You are receiving this mail because: ------- > You are on the CC list for the bug. -- Configure bugmail: http://sourceware.org/bugzilla/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are on the CC list for the bug. _______________________________________________ bug-binutils mailing list bug-binutils@gnu.org https://lists.gnu.org/mailman/listinfo/bug-binutils
