Building Rtems 4.10 using RSB on Fedora 25

Worth Burruss worth at motioncontrol.org
Mon Jan 30 14:18:16 UTC 2017


Ricardo,

Your errors look similar to what I saw for the m68k processor under windows and MSYS2.

Look at ticket number:2724 and see if it has anything to solve your problem.

https://devel.rtems.org/ticket/2724

Worth


On 26 Jan 2017 at 2:05, rmd wrote:

> Hello all, Chris
> 
> I'm trying to build rtems4.10 and sparc toolchain using 
> rtems-source-builder on a Fedora 25 x86_64 host, but I ran into an error 
> building gcc.
> In report file 
> rsb-report-sparc-rtems4.10-gcc-4.4.7-newlib-1.18.0-x86_64-linux-gnu-1.txt 
> this error cannot be found since its a tail of build log file, but 
> peeking into rsb-log-xx.txt I found:
> 
> ../../gcc-4.4.7/gcc/toplev.c: At top level:
> ../../gcc-4.4.7/gcc/toplev.c:536:1: error: redefinition of 'floor_log2'
>   floor_log2 (unsigned HOST_WIDE_INT x)
>   ^~~~~~~~~~
> In file included from ../../gcc-4.4.7/gcc/toplev.c:58:0:
> ../../gcc-4.4.7/gcc/toplev.h:190:1: note: previous definition of 
> 'floor_log2' was here
>   floor_log2 (unsigned HOST_WIDE_INT x)
>   ^~~~~~~~~~
> ../../gcc-4.4.7/gcc/toplev.c:571:1: error: redefinition of 'exact_log2'
>   exact_log2 (unsigned HOST_WIDE_INT x)
>   ^~~~~~~~~~
> In file included from ../../gcc-4.4.7/gcc/toplev.c:58:0:
> ../../gcc-4.4.7/gcc/toplev.h:196:1: note: previous definition of 
> 'exact_log2' was here
>   exact_log2 (unsigned HOST_WIDE_INT x)
>   ^~~~~~~~~~
> 
> My host is an up-to-date Fedora 25 system, and the gcc version installed 
> is gcc (GCC) 6.3.1 20161221 (Red Hat 6.3.1-1).
> 
> In toplev.c , floor_log2 and exact_log2 are defined in this snippet:
> ----
> /* When compiling with a recent enough GCC, we use the GNU C "extern inline"
>     for floor_log2 and exact_log2; see toplev.h.  That construct, however,
>     conflicts with the ISO C++ One Definition Rule.   */
> 
> #if ((GCC_VERSION < 3004) || defined(__clang__)) || !defined (__cplusplus)
> 
> /* Given X, an unsigned number, return the largest int Y such that 2**Y 
> <= X.
>     If X is 0, return -1.  */
> 
> int floor_log2 (unsigned HOST_WIDE_INT x)
> {
>      int t = 0;
>      ...
>      ...
>      return t;
> }
> 
> /* Return the logarithm of X, base 2, considering X unsigned,
>     if X is a power of 2.  Otherwise, returns -1.  */
> 
> int exact_log2 (unsigned HOST_WIDE_INT x)
> {
>      ...
>      ...
> }
> #endif /*  GCC_VERSION < 3004 || !defined (__cplusplus)  */
> ----
> 
> and in toplev.h:
> /* Return log2, or -1 if not exact.  */
> extern int exact_log2                  (unsigned HOST_WIDE_INT);
> 
> /* Return floor of log2, with -1 for zero.  */
> extern int floor_log2                  (unsigned HOST_WIDE_INT);
> 
> /* Inline versions of the above for speed.  */
> #if (GCC_VERSION >= 3004) && !defined(__clang__)
> # if HOST_BITS_PER_WIDE_INT == HOST_BITS_PER_LONG
> #  define CLZ_HWI __builtin_clzl
> #  define CTZ_HWI __builtin_ctzl
> # elif HOST_BITS_PER_WIDE_INT == HOST_BITS_PER_LONGLONG
> #  define CLZ_HWI __builtin_clzll
> #  define CTZ_HWI __builtin_ctzll
> # else
> #  define CLZ_HWI __builtin_clz
> #  define CTZ_HWI __builtin_ctz
> # endif
> 
> extern inline int floor_log2 (unsigned HOST_WIDE_INT x)
> {
>    return x ? HOST_BITS_PER_WIDE_INT - 1 - (int) CLZ_HWI (x) : -1;
> }
> 
> extern inline int exact_log2 (unsigned HOST_WIDE_INT x)
> {
>    return x == (x & -x) && x ? (int) CTZ_HWI (x) : -1;
> }
> #endif /* GCC_VERSION >= 3004 */
> 
> I think that, as in message 
> https://lists.rtems.org/pipermail/users/2016-March/030034.html, the 
> problem lays in the macro that determines GCC version, apparently broken 
> in newer versions.
> In that message thread, host GCC version was 5.1.x, and no proper 
> solution was found except patching gcc code, repackaging it and also 
> modifying RSB due to hashes verification.
> Also, I see that rtems patch for gcc4.4.7 in RSB 
> (gcc-core-4.4.7-rtems4.10-20120314.diff) code already includes a patch 
> to toplev.c/h files, but only for compiling with clang.
> 
> Is there any other solution?
> Thank you very much
> 
> Ricardo
> 
> 
> 
> 
> 
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