Re: [Xen-devel] [PATCH] xen: Deal with stdarg.h and -nostdinc

[Christoph Egger <Christoph.Egger@xxxxxxx>]

On 05/26/11 19:08, Keir Fraser wrote:
> On 26/05/2011 17:11, "Ian Jackson"<Ian.Jackson@xxxxxxxxxxxxx>  wrote:
>
> > Christoph Egger writes ("[Xen-devel] [PATCH] xen: Deal with stdarg.h and
> > -nostdinc"):
> > > For compiling the xen kernel we use -nostdinc which means
> > > we don't want to rely on any external headers.
> > > That also counts vor stdarg.h.
> > Right, OK, but:
> Not really. We are only doing the same as Linux right now. I do note that
> they add an -isystem option to their command line, with a gcc include path
> that they presumably dump out of gcc in some standard way. However, our
> current approach seems to work, if it fails to work in some situation it is
> likely to be pretty obvious (build or link failure), and we can fix it then.
The cross-compiling facility in NetBSD has been further improved which
made gcc more pendantic for this. -nostdinc is used and -isystem is 
*not* used.
> This stuff can be moderately fragile, and we've now had no actual bug
> reports about it in a long while.
Here is a full error message:

gcc -O2 -I/usr/include -I/usr/pkg/include -O2 -fomit-frame-pointer -m64 
-fno-strict-aliasing -std=gnu99 -Wall -Wstrict-prototypes 
-Wno-unused-value -Wdeclaration-after-statement  -O2 
-fomit-frame-pointer -m64 -fno-strict-aliasing -std=gnu99 -Wall 
-Wstrict-prototypes -Wno-unused-value -Wdeclaration-after-statement  -O2 
-fomit-frame-pointer -m64 -fno-strict-aliasing -std=gnu99 -Wall 
-Wstrict-prototypes -Wno-unused-value -Wdeclaration-after-statement 
-DNDEBUG -nostdinc -fno-builtin -fno-common -Wredundant-decls 
-iwithprefix include -Werror -Wno-pointer-arith -pipe 
-I/tmp/pkgsrc-obj/sysutils/xenkernel41/work.ixp/xen-4.1.0/xen/include 
-I/tmp/pkgsrc-obj/sysutils/xenkernel41/work.ixp/xen-4.1.0/xen/include/asm-x86/mach-generic 
-I/tmp/pkgsrc-obj/sysutils/xenkernel41/work.ixp/xen-4.1.0/xen/include/asm-x86/mach-default 
-msoft-float -fno-stack-protector -fno-exceptions -mno-red-zone
 -fpic -fno-asynchronous-unwind-tables -DGCC_HAS_VISIBILITY_ATTRIBUTE 
-g -D__XEN__ -MMD -MF .xen.d -O2 -fomit-frame-pointer -m64 
-fno-strict-aliasing -std=gnu99 -Wall -Wstrict-prototypes 
-Wno-unused-value -Wdeclaration-after-statement  -DNDEBUG -nostdinc 
-fno-builtin -fno-common -Wredundant-decls -iwithprefix include -Werror 
-Wno-pointer-arith -pipe 
-I/tmp/pkgsrc-obj/sysutils/xenkernel41/work.ixp/xen-4.1.0/xen/include 
-I/tmp/pkgsrc-obj/sysutils/xenkernel41/work.ixp/xen-4.1.0/xen/include/asm-x86/mach-generic 
-I/tmp/pkgsrc-obj/sysutils/xenkernel41/work.ixp/xen-4.1.0/xen/include/asm-x86/mach-default 
-msoft-float -fno-stack-protector -fno-exceptions -mno-red-zone -fpic 
-fno-asynchronous-unwind-tables -DGCC_HAS_VISIBILITY_ATTRIBUTE -g 
-D__XEN__ -MMD -MF .asm-offsets.s.d -S -o asm-offsets.s x86_64/asm-offsets.c
In file included from 
/tmp/pkgsrc-obj/sysutils/xenkernel41/work.ixp/xen-4.1.0/xen/include/xen/lib.h:5,
                 from 
/tmp/pkgsrc-obj/sysutils/xenkernel41/work.ixp/xen-4.1.0/xen/include/asm/system.h:4,
                 from 
/tmp/pkgsrc-obj/sysutils/xenkernel41/work.ixp/xen-4.1.0/xen/include/xen/spinlock.h:5,
                 from 
/tmp/pkgsrc-obj/sysutils/xenkernel41/work.ixp/xen-4.1.0/xen/include/xen/sched.h:7,
                 from x86_64/asm-offsets.c:10:
/tmp/pkgsrc-obj/sysutils/xenkernel41/work.ixp/xen-4.1.0/xen/include/xen/stdarg.h:4:22: 
error: stdarg.h: No such file or directory
In file included from 
/tmp/pkgsrc-obj/sysutils/xenkernel41/work.ixp/xen-4.1.0/xen/include/asm/system.h:4,
                 from 
/tmp/pkgsrc-obj/sysutils/xenkernel41/work.ixp/xen-4.1.0/xen/include/xen/spinlock.h:5,
                 from 
/tmp/pkgsrc-obj/sysutils/xenkernel41/work.ixp/xen-4.1.0/xen/include/xen/sched.h:7,
                 from x86_64/asm-offsets.c:10:
/tmp/pkgsrc-obj/sysutils/xenkernel41/work.ixp/xen-4.1.0/xen/include/xen/lib.h:86: 
error: expected declaration specifiers or '...' before 'va_list'
/tmp/pkgsrc-obj/sysutils/xenkernel41/work.ixp/xen-4.1.0/xen/include/xen/lib.h:90: 
error: expected declaration specifiers or '...' before 'va_list'
/tmp/pkgsrc-obj/sysutils/xenkernel41/work.ixp/xen-4.1.0/xen/include/xen/lib.h:94: 
error: expected declaration specifiers or '...' before 'va_list'
In file included from 
/tmp/pkgsrc-obj/sysutils/xenkernel41/work.ixp/xen-4.1.0/xen/include/acpi/acpi.h:61,
                 from 
/tmp/pkgsrc-obj/sysutils/xenkernel41/work.ixp/xen-4.1.0/xen/include/xen/acpi.h:34,
                 from 
/tmp/pkgsrc-obj/sysutils/xenkernel41/work.ixp/xen-4.1.0/xen/include/acpi/apei.h:8,
                 from 
/tmp/pkgsrc-obj/sysutils/xenkernel41/work.ixp/xen-4.1.0/xen/include/asm/fixmap.h:23,
                 from x86_64/asm-offsets.c:12:
/tmp/pkgsrc-obj/sysutils/xenkernel41/work.ixp/xen-4.1.0/xen/include/acpi/acpiosxf.h:257: 
error: expected declaration specifiers or '...' before 'va_list'
gmake[3]: *** [asm-offsets.s] Error 1
gmake[3]: Leaving directory 
`/tmp/pkgsrc-obj/sysutils/xenkernel41/work.ixp/xen-4.1.0/xen/arch/x86'
gmake[2]: *** 
[/tmp/pkgsrc-obj/sysutils/xenkernel41/work.ixp/xen-4.1.0/xen/xen] Error 2
gmake[2]: Leaving directory 
`/tmp/pkgsrc-obj/sysutils/xenkernel41/work.ixp/xen-4.1.0/xen'
gmake[1]: *** [install] Error 2
gmake[1]: Leaving directory 
`/tmp/pkgsrc-obj/sysutils/xenkernel41/work.ixp/xen-4.1.0/xen'

>   -- Keir
>
> > > Use the external header when we compile the tools.
> > > Adapt libelf-loader.c which is compiled in the kernel
> > > and with the tools.
> > -#include<stdarg.h>
> > +#include "../../include/xen/stdarg.h"
> >
> > Firstly, is this correct for all uses of libelf-loader ?  This file is
> > compiled both for use inside Xen and for use on the host.  In the
> > latter case it /should/ use the system's stdarg.h.
> >
> > Also, this kind of relative path should not be necessary.  The
> > relevant files should be on the include path.
> >
> > So I think this should be fixed by arranging that your new stdarg.h is
> > on the relevant include path, not by changing the .c file.
> >
> > Ian.
> >
> > _______________________________________________
> > Xen-devel mailing list
> > Xen-devel@xxxxxxxxxxxxxxxxxxx
> > http://lists.xensource.com/xen-devel

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