Date: Tue, 19 Feb 2013 20:29:58 +0200 From: Konstantin Belousov <kostikbel@gmail.com> To: mdf@FreeBSD.org Cc: freebsd-hackers@freebsd.org, Borja Marcos <borjam@sarenet.es> Subject: Re: Stupid question about integer sizes Message-ID: <20130219182958.GA2598@kib.kiev.ua> In-Reply-To: <CAMBSHm86GB1No3Zc97KYhDnH9nkUEuhawJu82WwScJE%2BqvS9Bg@mail.gmail.com> References: <77B93E04-9254-4EF1-8BDB-ED9214CEC2BC@sarenet.es> <CAMBSHm86GB1No3Zc97KYhDnH9nkUEuhawJu82WwScJE%2BqvS9Bg@mail.gmail.com>
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On Tue, Feb 19, 2013 at 06:52:34AM -0800, mdf@FreeBSD.org wrote:
> On Tue, Feb 19, 2013 at 5:11 AM, Borja Marcos <borjam@sarenet.es> wrote:
> >
> > Hello,
> >
> > I'm really sorry if this is a stupid question, but as far as I know, u_=
int64_t defined in /usr/include/sys/types.h should *always* be
> > a 64 bit unsigned integer, right?
> >
> > Seems there's a bug (or I need more and stronger coffee). Compiling a p=
rogram on a 64 bit system with -m32 gets the 64 bit integer types wrong.
> >
> > % cat tachin.c
> > #include <sys/types.h>
> > #include <stdio.h>
> >
> >
> > main()
> > {
> > printf("sizeof uint64_t =3D %d\n", sizeof(uint64_t));
> > printf("sizeof u_int64_t =3D %d\n", sizeof(u_int64_t));
> > }
> >
> >
> >
> > uname -a
> > FreeBSD splunk 9.1-RELEASE FreeBSD 9.1-RELEASE #14: Wed Jan 23 17:24:05=
CET 2013 root@splunk:/usr/obj/usr/src/sys/SPLUNK amd64
> >
> > % gcc -o tachin tachin.c
> > % ./tachin
> > sizeof uint64_t =3D 8
> > sizeof u_int64_t =3D 8
> >
> > % ./tachin
> > sizeof uint64_t =3D 4 <=3D=3D=3D=3D=3D=3D=3D WRON=
G!!
> > sizeof u_int64_t =3D 4 <=3D=3D=3D=3D=3D=3D=3D WRONG!!
> >
> > The same happens with clang.
> >
> > % clang -m32 -o tachin tachin.c
> > tachin.c:5:1: warning: type specifier missing, defaults to 'int' [-Wimp=
licit-int]
> > main()
> > ^~~~
> > 1 warning generated.
> > % ./tachin
> > sizeof uint64_t =3D 4 <=3D=3D=3D=3D=3D=3D=3D WRONG!!
> > sizeof u_int64_t =3D 4 <=3D=3D=3D=3D=3D=3D=3D WRONG!!
> >
> >
> > if I do the same on a i386 system (8.2-RELEASE, but it should be irrele=
vant) the u_int64 types have the correct size.
> >
> > %gcc -o tachin tachin.c
> > %./tachin
> > sizeof uint64_t =3D 8
> > sizeof u_int64_t =3D 8
> >
> >
> >
> >
> >
> > Am I missing anything? Seems like a too stupid problem to be a real bug=
=2E Sorry if I am wrong.
> >
>=20
> Last I knew -m32 still wasn't quite supported on 9.1. This is fixed
> in CURRENT. The problem in in the machine-dependent headers.
> sys/types.h includes sys/_types.h which includes machine/_types.h.
> But the machine alias can only point to one place; it's the amd64
> headers since you're running the amd64 kernel.
> sys/amd64/include/_types.h defines __uint64_t as unsigned long, which
> is correct in 64-bit mode but wrong in 32-bit mode.
>=20
> On CURRENT there is a merge x86/_types.h which uses #ifdef guards to
> define __uint64_t as unsigned long or unsigned long long, depending on
> __LP64__, so that the size is correct on a 32-bit compiler invocation.
Yes, but there are still some unconverted headers, mostly related to
the machine context and signal handlers.
Quick look:
machine/sigframe.h (probably not much useful for usermode)
machine/ucontext.h
machine/frame.h (again, usermode most likely does not need it)
machine/signal.h
machine/elf.h
libm machdep headers.
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