on 2011-5-28 6:23, Richard Purdie wrote:
> On Fri, 2011-05-27 at 22:24 +0100, Phil Blundell wrote:
>> On Fri, 2011-05-27 at 14:09 -0700, Saul Wold wrote:
>>> From: Yu Ke<ke.yu@intel.com>
>>>
>>> [YOCTO #737]
>>>
>>> The AC_CHECK_FUNC([dlopen], [], AC_CHECK_LIB([dl], [dlopen], DLOPEN_LIBS="-ldl"))
>>> macro seems not work well in ppc arch, so this patch force the DLOPEN_LIBS="-ldl"
>>>
>>
>> That's a bit of a weird report.  Do we know why it doesn't work?  I
>> guess we don't care all that much about Solaris targets, but equally I
>> can't think of any reason why ppc should be special.
>
> Seconded. I'd like to see the config.log of that failing on ppc...
>
> Cheers,
>
> Richard
>

The marco in question is in xorg-server-1.10.1/configure.ac
"
AC_CHECK_FUNC([dlopen], [],
     AC_CHECK_LIB([dl], [dlopen], DLOPEN_LIBS="-ldl"))
AC_SUBST(DLOPEN_LIBS)
"

Ideally, the dlopen test should fail since dlopen is not available in 
libc, and then DLOPEN_LIBS="-ldl" is executed. In this case, the later 
build will correctly link libdl. qemux86 fall into this case.

But in ppc case, the dlopen test unfortunately pass, and DLOPEN_LIBS 
become "", which caused later linker error of unresolved dlopen 
reference. but I did not yet understand why ppc is so special.

For detail, I've attached two config.log, one for ppc, one for qemux86.
in ppc,
configure:15235: checking for dlopen
configure:15235: result: yes

in qemux86:
configure:15235: checking for dlopen
configure:15235: i586-poky-linux-gcc -march=i586 
--sysroot=/home/kyu3/sdb/test/tmp/sysroots/qemux86 -std=gnu99 -o 
conftest -O2 -pipe -g -feliminate-unused-debug-types  -Wl,-O1 
-Wl,--as-needed conftest.c  >&5
/tmp/ccaQGSPX.o: In function `main':
/home/kyu3/sdb/test/tmp/work/i586-poky-linux/xserver-xf86-lite-1.10.1-r0/xorg-server-1.10.1/conftest.c:74: 
undefined reference to `dlopen'
collect2: ld returned 1 exit status
configure:15235: $? = 1
configure: failed program was:
| /* confdefs.h */
| #define PACKAGE_NAME "xorg-server"
| #define PACKAGE_TARNAME "xorg-server"
| #define PACKAGE_VERSION "1.10.1"
| #define PACKAGE_STRING "xorg-server 1.10.1"
| #define PACKAGE_BUGREPORT 
"https://bugs.freedesktop.org/enter_bug.cgi?product=xorg"
| #define PACKAGE_URL ""
| #define PACKAGE "xorg-server"
| #define VERSION "1.10.1"
| #define STDC_HEADERS 1
| #define HAVE_SYS_TYPES_H 1
| #define HAVE_SYS_STAT_H 1
| #define HAVE_STDLIB_H 1
| #define HAVE_STRING_H 1
| #define HAVE_MEMORY_H 1
| #define HAVE_STRINGS_H 1
| #define HAVE_INTTYPES_H 1
| #define HAVE_STDINT_H 1
| #define HAVE_UNISTD_H 1
| #define PACKAGE_VERSION_MAJOR 1
| #define PACKAGE_VERSION_MINOR 10
| #define PACKAGE_VERSION_PATCHLEVEL 1
| #define HAVE_DLFCN_H 1
| #define LT_OBJDIR ".libs/"
| #define YYTEXT_POINTER 1
| #define _FILE_OFFSET_BITS 64
| #define HAVE_DIRENT_H 1
| #define STDC_HEADERS 1
| #define HAVE_FCNTL_H 1
| #define HAVE_STDLIB_H 1
| #define HAVE_STRING_H 1
| #define HAVE_UNISTD_H 1
| #define HAVE_DLFCN_H 1
| #define HAVE_STROPTS_H 1
| #define HAVE_FNMATCH_H 1
| #define HAVE_SYS_UTSNAME_H 1
| #define SIZEOF_UNSIGNED_LONG 4
| #define HAVE_BYTESWAP_H 1
| /* end confdefs.h.  */
| /* Define dlopen to an innocuous variant, in case <limits.h> declares 
dlopen.
|    For example, HP-UX 11i <limits.h> declares gettimeofday.  */
| #define dlopen innocuous_dlopen
|
| /* System header to define __stub macros and hopefully few prototypes,
|     which can conflict with char dlopen (); below.
|     Prefer <limits.h> to <assert.h> if __STDC__ is defined, since
|     <limits.h> exists even on freestanding compilers.  */
|
| #ifdef __STDC__
| # include <limits.h>
| #else
| # include <assert.h>
| #endif
|
| #undef dlopen
|
| /* Override any GCC internal prototype to avoid an error.
|    Use char because int might match the return type of a GCC
|    builtin and then its argument prototype would still apply.  */
| #ifdef __cplusplus
| extern "C"
| #endif
| char dlopen ();
| /* The GNU C library defines this for functions which it implements
|     to always fail with ENOSYS.  Some functions are actually named
|     something starting with __ and the normal name is an alias.  */
| #if defined __stub_dlopen || defined __stub___dlopen
| choke me
| #endif
|
| int
| main ()
| {
| return dlopen ();
|   ;
|   return 0;
| }
configure:15235: result: no
configure:15239: checking for dlopen in -ldl
configure:15264: i586-poky-linux-gcc -march=i586 
--sysroot=/home/kyu3/sdb/test/tmp/sysroots/qemux86 -std=gnu99 -o 
conftest -O2 -pipe -g -feliminate-unused-debug-types  -Wl,-O1 
-Wl,--as-needed conftest.c -ldl   >&5
configure:15264: $? = 0
configure:15273: result: yes