Date: Thu, 21 Aug 2014 08:25:40 -0700 From: Khem Raj <raj.khem@...il.com> To: musl@...ts.openwall.com Subject: Re: the definition of (u)int64_t with gcc -m32 in stdint.h On Thu, Aug 21, 2014 at 8:15 AM, Natanael Copa <ncopa@...inelinux.org> wrote: > Hi, > > After migrating from uclibc to musl libc the Xen hvmloader broke. This > is a 32bit bootloader that is built on 64 bit hosts with gcc -m32. > > Someone told me breakage had to do with datastructs beeing 64 bit even > with -m32. I also saw someone comment that it shoudl been built with > -nostdinc. > > I tried this and it revealed that yes, indeed, the hvmloader does use > the host system stdint.h and stdarg.h. > > Curious on why it works on uclibc but not with musl i found out that > uclibc/glibc sets (u)int64_t depening on __WORDSIZE: > > # if __WORDSIZE == 64 > typedef long int int64_t; > # else > __extension__ > typedef long long int int64_t; > # endif > > > and wordsize is set in /usr/include/bits/wordsize.h: > /* Determine the wordsize from the preprocessor defines. */ > > #if defined __x86_64__ > # define __WORDSIZE 64 > /* This makes /var/run/utmp compatible with 32-bit environment: */ > # define __WORDSIZE_COMPAT32 1 > #else > # define __WORDSIZE 32 > #endif > > > the __x86_64__ define is set by gcc and is set differently when -m32 is > specified or not. > > A testcase. On uclibc 64 bit host: > dev-2-7-x86_64:~$ echo '#include <stdint.h>' | gcc -m32 -E - | grep int64 > typedef long long int int64_t; > typedef unsigned long long int uint64_t; > > > Same on musl libc 64 bit host: > $ echo '#include <stdint.h>' | gcc -m32 -E - | grep int64 > typedef long int64_t; > typedef unsigned long uint64_t; > typedef int64_t int_fast64_t; > typedef int64_t int_least64_t; > typedef uint64_t uint_fast64_t; > typedef uint64_t uint_least64_t; > > > so on musl it is 'long' but on uclibc its 'long long int'. > > That explains why it works on uclibc but not on musl. > > Now, what is the proper way to fix it? Preferible without replacing > all (u)int*_t all places in xen code. I doubt upstream will accept that. > Do we support multilib with musl yes ? > -nc
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