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Re: [Xen-devel] [PATCH] xen: Deal with stdarg.h and -nostdinc
On 05/27/11 11:21, Keir Fraser wrote:
On 27/05/2011 08:55, "Christoph Egger"<Christoph.Egger@xxxxxxx> wrote:
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:
Ah, okay, actually I see our stdarg support is a bit inconsistent already.
How about the attached alternative fix? A few notes about it:
Firstly, in xen/stdarg.h I handle NetBSD the same as OpenBSD -- I go and
grab /usr/include/stdarg.h directly. I don't know if that is really better
than including the compiler intrinsics directly as you did. If you prefer we
could do that instead, but whichever I think it makes sense to do the same
for both BSD variants.
No, the assumption what works for one BSD works for all BSDs is wrong.
In the NetBSD case I get the error
that <machine/ansi.h> and <sys/featuretest.h> are not found.
That way <stdarg.h> pulls in machine specific definitions on NetBSD.
Secondly, I wonder whether *BSD would be happier if we did not include
-nostdinc on the command line? See arch/x86/Rules.mk where SunOS is already
special cased. I don't know whether that would work for BSD too.
It works for NetBSD at least.
Finally, rather than referencing a hardcoded /usr/include path or including
gcc intrinsics in xen/stdarg.h, would *BSD prefer a -isystem command-line
option to include the gcc headers in the search path? Then we could perhaps
even get rid of xen/stdarg.h completely.
NetBSD is about to add clang/llvm support. If -isystem works for both
gcc and clang then this should be fine.
Christoph
-- Keir
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/spinlo
ck.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/spinlo
ck.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/acpio
sxf.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.
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