Re: [Xen-devel] [PATCH] xen: Don't use -nostdinc flags with CLANG

[Tim Deegan <tim@xxxxxxx>]

At 14:24 +0000 on 11 Feb (1392125052), Julien Grall wrote:
> (Add George as release manager)
> 
> On 11/02/14 13:59, Tim Deegan wrote:
> > At 13:20 +0000 on 11 Feb (1392121252), Julien Grall wrote:
> >>
> >>
> >> On 11/02/14 12:59, Tim Deegan wrote:
> >>> Are you using a very old version of clang?  As 06a9c7e points out,
> >>> our current runes didn't work before clang v3.0.
> >>
> >> I'm using clang 3.5 (which have other issue to compile Xen), but I have
> >> also tried 3.0 and 3.3.
> >>
> >>> If not, rather than chasing this around any further, I think we should
> >>> abandon trying to use the compiler-provided headers even on linux.
> >>> Does this patch fix your build issue?
> >>>
> >>> commit e7003f174e0df9192dde6fa8d33b0a20f99ce053
> >>> Author: Tim Deegan <tim@xxxxxxx>
> >>> Date:   Tue Feb 11 12:44:09 2014 +0000
> >>>
> >>>       xen: stop trying to use the system <stdarg.h> and <stdbool.h>
> >>
> >> With this patch, -iwithprefix include is not necessary now. I wondering
> >> if we can remove it from the command line.
> >
> > Yes, I think so.
> >
> >>>       We already have our own versions of the stdarg/stdbool definitions, 
> >>> for
> >>>       systems where those headers are installed in /usr/include.
> >>>
> >>>       On linux, they're typically installed in compiler-specific paths, 
> >>> but
> >>>       finding them has proved unreliable.  Drop that and use our own 
> >>> versions
> >>>       everywhere.
> >>>
> >>>       Signed-off-by: Tim Deegan <tim@xxxxxxx>
> >>
> >> This patch is working fine to build xen clang 3.0, 3.3.
> >> I have others issue to build with clang 3.5.
> >>
> >> Tested-by: Julien Grall <julien.grall@xxxxxxxxxx>
> >
> > Great!  Assuming you'll have a series of patches to fix the clang-3.5
> > build, do you want to just take this into that series, and drop the
> > -iwithprefix at the same time?
> 
> If it's possible I'd like this patch goes in Xen 4.4 to fix build with 
> official version of clang (until 3.4).
> 
> Clang 3.5 is still under development, so I don't think it's important to 
> have support for it in Xen 4.4.

Fair enough.  In that case it needs a release ack from George.  It:
 - fixes a compile issue on some version s of clang;
 - might cause a regression with other compilers, but the regression
   is likely to be obvious (i.e. a compile-time failure).

And it needs an ack from Keir, for changing common code. 

v2 is below, removing "-iwithprefix".  I've kept your tested-by; hope
that's OK.

Cheers,

Tim.

commit 1d62fcb9ad8d2b409ac2cf0e8a3824e19ca3313f
Author: Tim Deegan <tim@xxxxxxx>
Date:   Tue Feb 11 12:44:09 2014 +0000

    xen: stop trying to use the system <stdarg.h> and <stdbool.h>
    
    We already have our own versions of the stdarg/stdbool definitions, for
    systems where those headers are installed in /usr/include.
    
    On linux, they're typically installed in compiler-specific paths, but
    finding them has proved unreliable.  Drop that and use our own versions
    everywhere.
    
    Signed-off-by: Tim Deegan <tim@xxxxxxx>
    Tested-by: Julien Grall <julien.grall@xxxxxxxxxx>

diff --git a/xen/Rules.mk b/xen/Rules.mk
index df1428f..3a6cec5 100644
--- a/xen/Rules.mk
+++ b/xen/Rules.mk
@@ -44,10 +44,7 @@ ALL_OBJS-$(x86)          += $(BASEDIR)/crypto/built_in.o
 CFLAGS += -fno-builtin -fno-common
 CFLAGS += -Werror -Wredundant-decls -Wno-pointer-arith
 CFLAGS += -pipe -g -D__XEN__ -include $(BASEDIR)/include/xen/config.h
-# Solaris puts stdarg.h &c in the system include directory.
-ifneq ($(XEN_OS),SunOS)
-CFLAGS += -nostdinc -iwithprefix include
-endif
+CFLAGS += -nostdinc
 
 CFLAGS-$(XSM_ENABLE)    += -DXSM_ENABLE
 CFLAGS-$(FLASK_ENABLE)  += -DFLASK_ENABLE -DXSM_MAGIC=0xf97cff8c
diff --git a/xen/include/xen/stdarg.h b/xen/include/xen/stdarg.h
index d1b2540..0283f06 100644
--- a/xen/include/xen/stdarg.h
+++ b/xen/include/xen/stdarg.h
@@ -1,23 +1,21 @@
 #ifndef __XEN_STDARG_H__
 #define __XEN_STDARG_H__
 
-#if defined(__OpenBSD__) || defined(__NetBSD__) || defined(__FreeBSD__)
-   typedef __builtin_va_list va_list;
-#  ifdef __GNUC__
-#    define __GNUC_PREREQ__(x, y)                                       \
-        ((__GNUC__ == (x) && __GNUC_MINOR__ >= (y)) ||                  \
-         (__GNUC__ > (x)))
-#  else
-#    define __GNUC_PREREQ__(x, y)   0
-#  endif
-#  if !__GNUC_PREREQ__(4, 5)
-#    define __builtin_va_start(ap, last)    __builtin_stdarg_start((ap), 
(last))
-#  endif
-#  define va_start(ap, last)    __builtin_va_start((ap), (last))
-#  define va_end(ap)            __builtin_va_end(ap)
-#  define va_arg                __builtin_va_arg
+#ifdef __GNUC__
+#  define __GNUC_PREREQ__(x, y)                                       \
+      ((__GNUC__ == (x) && __GNUC_MINOR__ >= (y)) ||                  \
+       (__GNUC__ > (x)))
 #else
-#  include <stdarg.h>
+#  define __GNUC_PREREQ__(x, y)   0
 #endif
 
+#if !__GNUC_PREREQ__(4, 5)
+#  define __builtin_va_start(ap, last)    __builtin_stdarg_start((ap), (last))
+#endif
+
+typedef __builtin_va_list va_list;
+#define va_start(ap, last)    __builtin_va_start((ap), (last))
+#define va_end(ap)            __builtin_va_end(ap)
+#define va_arg                __builtin_va_arg
+
 #endif /* __XEN_STDARG_H__ */
diff --git a/xen/include/xen/stdbool.h b/xen/include/xen/stdbool.h
index f0faedf..b0947a6 100644
--- a/xen/include/xen/stdbool.h
+++ b/xen/include/xen/stdbool.h
@@ -1,13 +1,9 @@
 #ifndef __XEN_STDBOOL_H__
 #define __XEN_STDBOOL_H__
 
-#if defined(__OpenBSD__) || defined(__NetBSD__) || defined(__FreeBSD__)
-#  define bool _Bool
-#  define true 1
-#  define false 0
-#  define __bool_true_false_are_defined   1
-#else
-#  include <stdbool.h>
-#endif
+#define bool _Bool
+#define true 1
+#define false 0
+#define __bool_true_false_are_defined   1
 
 #endif /* __XEN_STDBOOL_H__ */

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