problem in compiling gcc6.4.0 using gcc8.1.1

[C.J.]

Thank you for your informations!

However, there are still many bug in gcc-6.4.0 installation(see attachment
below). It seems something complicated, but it's necessary for the
installation of some soft.
Is there a solution for all the bugs, like a bug-fixed 6.4.0 version? I
need to install a old version gcc(<7.0). Thank you!

Regards!
Jianhao

= = = = = = = = = = = = = = =
attached message:

/home/rx/program/gcc-6.4.0/x86_64-pc-linux-gnu/libssp/../.././libssp/gets-chk.c:74:
warning: the `gets' function is dangerous and should not be used.
../../.././libsanitizer/sanitizer_common/sanitizer_posix.cc: In function
‘__sanitizer::fd_t __sanitizer::OpenFile(const char*,
__sanitizer::FileAccessMode, __sanitizer::error_t*)’:
../../.././libsanitizer/sanitizer_common/sanitizer_posix.cc:179:27:
warning: ‘flags’ may be used uninitialized in this function
[-Wmaybe-uninitialized]
   fd_t res = internal_open(filename, flags, 0660);
              ~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
In file included from
../../.././libsanitizer/asan/asan_interceptors.cc:196:0:
../../.././libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:
In function ‘__sanitizer::uptr __interceptor_ptrace(int, int, void*,
void*)’:
../../.././libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:2449:21:
warning: ‘local_iovec.__sanitizer::__sanitizer_iovec::iov_len’ may be used
uninitialized in this function [-Wmaybe-uninitialized]
   __sanitizer_iovec local_iovec;
                     ^~~~~~~~~~~
../../.././libsanitizer/asan/asan_interceptors.cc:56:34: warning:
‘local_iovec.__sanitizer::__sanitizer_iovec::iov_base’ may be used
uninitialized in this function [-Wmaybe-uninitialized]
     uptr __offset = (uptr)(offset);                                     \
                                  ^
In file included from
../../.././libsanitizer/asan/asan_interceptors.cc:196:0:
../../.././libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:2449:21:
note: ‘local_iovec.__sanitizer::__sanitizer_iovec::iov_base’ was declared
here
   __sanitizer_iovec local_iovec;
                     ^~~~~~~~~~~
In file included from
../../.././libsanitizer/tsan/tsan_interceptors.cc:2338:0:
../../.././libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:
In function ‘__sanitizer::uptr __interceptor_ptrace(int, int, void*,
void*)’:
../../.././libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:2498:58:
warning: ‘local_iovec.__sanitizer::__sanitizer_iovec::iov_len’ may be used
uninitialized in this function [-Wmaybe-uninitialized]
                                      local_iovec.iov_len);
                                                          ^
../../.././libsanitizer/tsan/tsan_interceptors.cc:2240:20: warning:
‘local_iovec.__sanitizer::__sanitizer_iovec::iov_base’ may be used
uninitialized in this function [-Wmaybe-uninitialized]
   MemoryAccessRange(((TsanInterceptorContext *)ctx)->thr,                 \
                    ^
In file included from
../../.././libsanitizer/tsan/tsan_interceptors.cc:2338:0:
../../.././libsanitizer/sanitizer_common/sanitizer_common_interceptors.inc:2449:21:
note: ‘local_iovec.__sanitizer::__sanitizer_iovec::iov_base’ was declared
here
   __sanitizer_iovec local_iovec;
                     ^~~~~~~~~~~

Jonathan Wakely <jwakely.gcc@gmail.com> 于2018年9月26日周三 下午4:58写道：

> On Wed, 26 Sep 2018 at 02:07, C.J. wrote:
> >
> > Dear specialists,
> >
> > I tried to install gcc6.4.0 in Fedora28, while something wrong happened
> as
> > following.
> >
> >     In file included from ../.././libgcc/unwind-dw2.c:401:0:
> >     ./md-unwind-support.h: In function ‘x86_64_fallback_frame_state’:
> >     ./md-unwind-support.h:65:47: error: dereferencing pointer to
> incomplete
> > type ‘struct ucontex_t’
>
> Are you sure the error says "ucontex_t"? That's not a valid type. It
> should be either "struct ucontext" or ucontext_t. Not "struct
> ucontex_t".
>
> Assuming it really says "struct ucontext" the fix you need is:
>
> https://gcc.gnu.org/viewcvs/gcc/trunk/libgcc/config/i386/linux-unwind.h?r1=249731&r2=249730&pathrev=249731
>


-- 
Best regards!
C.J.