Package: simgear
Version: 1.0.0-1
Severity: serious
simgear is now failing to build on alpha, hppa, and s390 with the following
error:
if gcc -DHAVE_CONFIG_H -I. -I. -I../../simgear -I../.. -fPIC -pipe -g -O2
-D_REENTRANT -MT bitslib.o -MD -MP -MF ".deps/bitslib.Tpo" -c -o bitslib.o
bitslib.c; \
then mv -f ".deps/bitslib.Tpo" ".deps/bitslib.Po"; else rm -f
".deps/bitslib.Tpo"; exit 1; fi
In file included from nasal.h:7,
from data.h:4,
from bitslib.c:2:
naref.h:20:3: error: #error Unrecognized CPU architecture
[...]
A full build log can be found at
<http://buildd.debian.org/fetch.cgi?pkg=simgear&arch=alpha&ver=1.0.0-1&stamp=1198415406&file=log&as=raw>.
The reason for this is the following code in naref.h:
/* Rather than play elaborate and complicated games with
* platform-dependent endianness headers, just detect the platforms we
* support. This list is simpler and smaller, yet still quite
* complete. */
#if (defined(__x86_64) && defined(__linux__)) || defined(__sparcv9) || \
defined(__powerpc64__)
/* Win64 and Irix should work with this too, but have not been
* tested */
# define NASAL_NAN64
#elif defined(_M_IX86) || defined(i386) || defined(__x86_64) || \
defined(__ia64__) || defined(_M_IA64) || defined(__ARMEL__)
# define NASAL_LE
#elif defined(__sparc) || defined(__ppc__) ||defined(__PPC) || \
defined(__mips) || defined(__ARMEB__)
# define NASAL_BE
#else
# error Unrecognized CPU architecture
#endif
... which is a cop-out, and a serious regression because the old code built
and ran fine on all architectures.
The above code should have __alpha__ added to the NASAL_LE list, and
__hppa__, __s390__, and __s390x__ added to the NASAL_BE list.
BTW, according to data.h, the NASAL_NAN64 option exists to support stupid
union tricks:
// On 64 bit systems, Nasal non-numeric references are stored with a
// bitmask that sets the top 16 bits. As a double, this is a
// signalling NaN that cannot itself be produced by normal numerics
// code. The pointer value can be reconstructed if (and only if) we
// are guaranteed that all memory that can be pointed to by a naRef
// (i.e. all memory returned by naAlloc) lives in the bottom 48 bits
// of memory. Linux on x86_64, Win64, Solaris and Irix all have such
// policies with address spaces:
[...] Linux doesn't document this rigorously, but testing
// shows that it allows 47 bits of address space (and current x86_64
// implementations are limited to 48 bits of virtual space anyway). So
// we choose 48 as the conservative compromise.
So this assumes the kernel will never expose more than 48bits of address
space to userspace processes -- a short-sighted and groundless assumption,
the reason Linux hasn't "documented this rigorously" is because there is no
such guarantee. The NASAL_NAN64 option should be thrown out for all Linux
variants.
--
Steve Langasek Give me a lever long enough and a Free OS
Debian Developer to set it on, and I can move the world.
Ubuntu Developer http://www.debian.org/
[EMAIL PROTECTED] [EMAIL PROTECTED]
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