Fix gdb 7.12 C++ compilation on Solaris
Rainer Orth
ro@CeBiTec.Uni-Bielefeld.DE
Tue Oct 18 13:14:00 GMT 2016
Hi Pedro,
> On 10/14/2016 03:45 PM, Rainer Orth wrote:
>> gdb 7.12 doesn't compile as C++ (tried with g++ 4.9) on Solaris (tried
>> 10 and 12, sparc and x86). The following patch (relative to the 7.12
>> release, though I expect most if not all issues to be present on trunk,
>> too) fixes this.
>>
>> Only a few of the changes bear explanation:
>>
>> * Initially, compilation failed whereever defs.h. was included:
>>
>> In file included from /vol/src/gnu/gdb/gdb-7.12/gdb/gdb.c:19:0:
>> /vol/src/gnu/gdb/gdb-7.12/gdb/defs.h:630:33: error: 'double atof(const char*)' conflicts with a previous declaration
>> extern double atof (const char *); /* X3.159-1989 4.10.1.1 */
>> ^
>> In file included from /usr/include/stdlib.h:17:0,
>> from build-gnulib/import/stdlib.h:36,
>> from /vol/src/gnu/gdb/gdb-7.12/gdb/common/common-defs.h:32,
>> from /vol/src/gnu/gdb/gdb-7.12/gdb/defs.h:28,
>> from /vol/src/gnu/gdb/gdb-7.12/gdb/gdb.c:19:
>> /vol/gcc-4.9/lib/gcc/i386-pc-solaris2.10/4.9.0/include-fixed/iso/stdlib_iso.h:119:15: note: previous declaration 'double std::atof(const char*)'
>> extern double atof(const char *);
>> ^
>>
>> This is due to this gem in gdb/defs.h which seems to have been present
>> like forever:
>>
>> #ifndef atof
>> extern double atof (const char *); /* X3.159-1989 4.10.1.1 */
>> #endif
>>
>> In the Solaris headers, the appropriate functions are in namespace std,
>> thus the conflict. I've wrapped the defs.h declaration in !__cplusplus
>> to avoid this; perhaps it can go completely instead.
>
> master dropped support for building with a C compiler, it's C++-only.
> So for master, just delete the thing.
>
> On both branches, please delete the whole comment above as well:
>
> /* Global functions from other, non-gdb GNU thingies.
> Libiberty thingies are no longer declared here. We include libiberty.h
> above, instead. */
>
> /* From other system libraries */
>
> as it no longer makes any sense afterwards.
done in the attached revised patch.
>> * All the casts are necessary to appease g++ and should be pretty
>> obvious.
>>
>> * The sol-thread.c changes are here to handle
>>
>> /vol/src/gnu/gdb/gdb-7.12/gdb/sol-thread.c: In function 'void _initialize_sol_thread()':
>> /vol/src/gnu/gdb/gdb-7.12/gdb/sol-thread.c:1252:36: error: invalid conversion from 'void*' to 'void (*)(int)' [-fpermissive]
>> if (!(p_##X = dlsym (dlhandle, #X))) \
>> ^
>> /vol/src/gnu/gdb/gdb-7.12/gdb/sol-thread.c:1255:3: note: in expansion of macro 'resolve'
>> resolve (td_log);
>> ^
>>
>> and are modeled after linux-thread-db.c (try_thread_db_load_1).
>>
>> The patch allowed both 32 and 64-bit C++ builds on sparc-sun-solaris2.10
>> and i386-pc-solaris2.10 to complete. The resulting binary hasn't seen
>> more than a smoke test (invoke it on itself, b main, run) yet.
>>
>> Ok for mainline and 7.12 branch?
>
> Yes, with the tweak above on master. But, the process for getting
Thanks. When investigating the failure to detect -static-libstdc++
support (more below), I found two more issues which only show up with
-Werror:
/vol/src/gnu/gdb/gdb/local/gdb/procfs.c: In function 'ssd* proc_get_LDT_entry(procinfo*, int)':
/vol/src/gnu/gdb/gdb/local/gdb/procfs.c:2487:19: error: variable 'old_chain' set but not used [-Werror=unused-but-set-variable]
struct cleanup *old_chain = NULL;
^
Unless I'm mistaken, you need to run do_cleanups on every return from
the function.
Afterwards, I ran a 32-bit compilation, which (after adding
--disable-largefile to avoid
In file included from /usr/include/sys/procfs.h:28:0,
from /vol/src/gnu/gdb/gdb/local/gdb/i386-sol2-nat.c:23:
/usr/include/sys/old_procfs.h:39:2: error: #error "Cannot use procfs in the large file compilation environment"
#error "Cannot use procfs in the large file compilation environment"
^
and two more instances) revealed
/vol/src/gnu/gdb/gdb/local/gdb/top.c: In function 'void gdb_safe_append_history()':
/vol/src/gnu/gdb/gdb/local/gdb/top.c:1170:59: error: format '%d' expects argument of type 'int', but argument 3 has type 'pid_t {aka long int}' [-Werror=format=]
= xstrprintf ("%s-gdb%d~", history_filename, getpid ());
^
Fixed by casting pid_t to long and printing it as such.
Still ok for mainline?
> fixes into the branch involves filing a PR. The reason is that the
> PR's subject is later used to help create the release announcement
> (manually). So please file a bug ("gdb 7.12 doesn't build on Solaris"
> or some such, and paste an example build error log).
Done now (PR build/20712).
>> Besides, when I compiled with g++ 4.9 installed into a non-default
>> location, gdb wouldn't run initially since libstdc++.so.6 and
>> libgcc_s.so.1 weren't found. Maybe it would be good to handle this as
>> gcc does and just link with -static-libstdc++ -static-libgcc?
>
> That's already included in the link line for me on GNU/Linux.
> Maybe it's host-specific? I've wondered before about why don't
> we use rpath instead though.
This turned out to be (sort of) pilot error: since I'd started with
building a 64-bit gdb with a 32-bit-default gcc, I had to configure with
CFLAGS='-g -O2 -m64' and now added CXXFLAGS='$(CFLAGS)'. However, this
didn't work as intended, but passed a literal "$(CFLAGS)" to C++
compilations, breaking/confusing several configure tests like the one
for -static-libstdc++ or the -Werror one. Once I duplicated the
necessary options in CXXFLAGS, everything went fine and libstdc++ was
linked statically as expected.
Rainer
--
-----------------------------------------------------------------------------
Rainer Orth, Center for Biotechnology, Bielefeld University
2016-10-14 Rainer Orth <ro@CeBiTec.Uni-Bielefeld.DE>
* defs.h: Remove obsolete comment
(atof): Remove.
* procfs.c (do_destroy_procinfo_cleanup): Add cast.
(sysset_t_alloc): Likewise.
(proc_set_traced_sysentry): Likewise.
(proc_set_traced_sysexit): Likewise.
[!PIOCLSTATUS && NEW_PROC_API] (do_closedir_cleanup): Likewise.
(proc_get_LDT_entry): Initiate cleanups before returns.
(procfs_wait): Use GDB_SIGNAL_0.
(procfs_corefile_thread_callback): Add cast.
* sol-thread.c (td_log_ftype, td_ta_new_ftype, td_ta_delete_ftype)
(td_init_ftype, td_ta_get_ph_ftype, td_ta_get_nthreads_ftype)
(td_ta_tsd_iter_ftype, td_ta_thr_iter_ftype)
(td_thr_validate_ftype, td_thr_tsd_ftype, td_thr_get_info_ftype)
(td_thr_getfpregs_ftype, td_thr_getxregsize_ftype)
(td_thr_getxregs_ftype, td_thr_sigsetmask_ftype)
(td_thr_setprio_ftype, td_thr_setsigpending_ftype)
(td_thr_setfpregs_ftype, td_thr_setxregs_ftype)
(td_ta_map_id2thr_ftype, td_ta_map_lwp2thr_ftype)
(td_thr_getgregs_ftype, td_thr_setgregs_ftype): New typedefs.
(p_td_log, p_td_ta_new, p_td_ta_delete, p_td_init, p_td_ta_get_ph)
(p_td_ta_get_nthreads, p_td_ta_tsd_iter, p_td_ta_thr_iter)
(p_td_thr_validate, p_td_thr_tsd, p_td_thr_get_info)
(p_td_thr_getfpregs, p_td_thr_getxregsize, p_td_thr_getxregs)
(p_td_thr_sigsetmask, p_td_thr_setprio, p_td_thr_setsigpending)
(p_td_thr_setfpregs, p_td_thr_setxregs, p_td_ta_map_id2thr)
(p_td_ta_map_lwp2thr, p_td_thr_getgregs, p_td_thr_setgregs): Use them.
(ps_pdread): Add cast.
(ps_ptread): Likewise.
(resolve): Likewise.
* top.c (gdb_safe_append_history): Print pid_t as long.
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