ID: 42374
Comment by: crrodriguez at suse dot de
Reported By: galtgendo at o2 dot pl
Status: Assigned
Bug Type: Compile Failure
Operating System: Gentoo
PHP Version: 5.2CVS-2007-08-23
Assigned To: jani
New Comment:
>a) it seems to be experimental
yes, but it usually work.
>b) might cause problems in dynamic loading such as our shared
>extensions, f.e. php -> pdo -> pdo driver (haven't tested yet :)
I have tested it with some extensions and seem to work fine, except
that the IMAP extension does not compile because configure checks fail
for the same reason the reporter is showing here.
>d) PHP build system does not link with anything else than what is
>actually needed anyway (AFAIK)
ldd -u -r /usr/bin/php
Unused direct dependencies:
/lib/libnsl.so.1
/lib/libz.so.1
ldd -u -r xmlreader.so
/lib/libz.so.1
/lib/libm.so.6
dom.so
Unused direct dependencies:
/lib/libz.so.1
/lib/libm.so.6
gd.so
Unused direct dependencies:
/usr/lib/libX11.so.6
although in most cases the guilty stuff is "foobar_config" scripts or
pkgconfig scripts that inject "uneeded" dependencies (uneeded at least
on linux)
Previous Comments:
------------------------------------------------------------------------
[2007-08-23 23:01:01] [EMAIL PROTECTED]
After some investigation to this flag I'm leaning towards simply
filtering it out totally if someone tries to use it. Reasons being:
a) it seems to be experimental
b) might cause problems in dynamic loading such as our shared
extensions, f.e. php -> pdo -> pdo driver (haven't tested yet :)
c) requires that pretty much everything in the system has to be
compiled using it
d) PHP build system does not link with anything else than what is
actually needed anyway (AFAIK)
------------------------------------------------------------------------
[2007-08-23 15:30:49] galtgendo at o2 dot pl
For a simple test case:
#include <glib.h>
int main()
{
g_print("test done\n");
return 0;
}
gcc -o minitest -Wl,--as-needed `pkg-config glib-2.0 --cflags`
minitest.c `pkg-config glib-2.0 --libs`
- compiles fine
gcc -o minitest -Wl,--as-needed `pkg-config glib-2.0 --cflags`
`pkg-config glib-2.0 --libs` minitest.c
- gives
/tmp/ccKZrHDW.o: In function `main':
minitest.c:(.text+0x19): undefined reference to `g_print'
collect2: ld returned 1 exit status
------------------------------------------------------------------------
[2007-08-23 15:21:10] galtgendo at o2 dot pl
Well, that's incorrect.
PHP_CHECK_LIBRARY calls AC_CHECK_LIB.
without -Wl,--as-needed it does not matter whether libs are in LDFLAGS
or in LIBS, with that flag however all dependent libraries must appear
after the objects.
AC_CHECK_LIB does something like
i686-pc-linux-gnu-gcc -o conftest ${CFLAGS} ${LDFLAGS} conftest.c
${LIBS}
(more or less)
that check fails with --as-needed flag if lib is added to LDFLAGS
so it does not matter if it gets restored, cause the check already
failed - those are the false negatives I'm talking about.
All the other macros from the patch seem to do this, so that's why I
changed them. I'm not sure if something got broken, however it was
correct for the ext/ldap/config.m4 so there's at least a chance it will
work for the rest.
------------------------------------------------------------------------
[2007-08-23 10:38:24] [EMAIL PROTECTED]
PHP_CHECK_LIBRARY restores the LDFLAGS after doing the test so it
shouldn't be any problem?
And bug #41973 was about ext/ldap and that was fixed.
I'd fix these case by case rather than blindly changing places unlikely
to even cause any problems.
------------------------------------------------------------------------
[2007-08-22 15:40:41] galtgendo at o2 dot pl
Well, I'm not 100%, if I was, I would mentioned it, not asked for
futher testing.
And AFAIK that commit from bug #41973 was only
http://cvs.php.net/viewvc.cgi/php-src/ext/ldap/config.m4?r1=1.44&r2=1.45&diff_format=u
so only about ext/ldap/config.m4 (as in my patch).
What's more, although I can't recall if it made any difference you
should consider changes in acinclude.m4, cause in PHP_CHECK_LIBRARY
macro you were adding libraries to LDFLAGS instead of LIBS and that's
most common source of --as-needed bugs. That's why I'm talking about
false negatives - standard configure check would put those libraries in
wrong place and check would fail even if the library was OK.
------------------------------------------------------------------------
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the rest of the comments, please view the bug report online at
http://bugs.php.net/42374
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