KDE 3.4.3 and -fvisibility-inlines-hidden

Question

Hi folks,
First of... Arch is great (migrated from Slack ). And yea, it's great that it's optimised for i686 and such
However the KDE packages in Arch are a bit... slow I mean I have a decent (but not a high-end) system (Ath-XP 2500, 512 MB DDR400), but I still had to wait a bit for Konqueror to open (I use it as a file manager, my browser is Firefox).
Now, what I've heard was that -fivisibility-inlines-hidden thingy in gcc 4.0 speeds up C++ applications. Yea, I've heard that these flags are added automagically during ./configure while building KDE, but I've never been able to spot them in gcc compile commands while make'ing.
Thus, I've decided to give it a shot myself and recompile some (since I don't use the rest that often) KDE packages using the following flags:
export CFLAGS="-march=athlon-xp -O2 -pipe -fomit-frame-pointer"
export CXXFLAGS="-march=athlon-xp -O2 -pipe -fomit-frame-pointer -fvisibility-inlines-hidden"
And yea.. I know some of you will now say: hey, Arch is not an athlon-xp optimised distro, but a generic 686 one. Yea, I know. But AFAIK the athlon-xp specific optimisations don't have such a  big meaning (being SSE, 3dNow and such mostly) to normal aps.
I've recompiled the following packages:
kdelibs
kdebase
kdeutils
kdegraphics
And you know what? I don't have to wait for Konqueror anymore. It opens in a blink of an eye. So does Kpdf with large documents. And yea.. I know these aren't hard numbers but rather impressions...
I'm aware that there has been a discussion regarding these flags before... but I couldn't make out the final outcome of them So, could anyone enlighten me: are the Arch stock KDE package compiled with fvisibility-inslines-hidden already? My guess is no, since when I tried to build KDE using the vanilla PKGBUILDS from ABS, there were no fvisibility flags in the compilation commands invoked by make. Of course I can be wrong, but if the stock packages aren't built with them, mayby they should be?
Also, does anyone have clue why I can't use  -fvisibility=hidden with the stock GCC 4.03? During C++ program compilation it says  that the -fivisibility=hidden attribute is not recognized. -fvisibility-inlines-hidden worked well.. but that one doesn't. Anyone?[/code]

Answer 1

Neuro wrote:As far as I understand correctly, the bug report tpowa pointed us to says that there were some issues with KDE 3.4.x GCC 4.0.2 and -fvisibility. It was traced back to an issue with a missing visibility declaration somewhere in the STL lib of C++. I've stumbled upon an information that it is fixed in GCC 4.0.3, but if I get the bug info right, since then KDE builds without -fvisibility even if the compiler allows it.
Actually, I it seems that our libstdc++ is working properly. My logs for the kdelibs builds show:
checking grepping for visibility push/pop in headers... yes
The test above was added to fix Bug 111115, mentioned by tpowa above. I you look at the configure patch below you'll see that `yes' should indicate that our libstdc++ is handling visibility correctly:
AC_REQUIRE([AC_PATH_QT])
+ AC_MSG_CHECKING([grepping for visibility push/pop in headers])
+
if test "x$GXX" = "xyes"; then
+ AC_LANG_SAVE
+ AC_LANG_CPLUSPLUS
+ AC_EGREP_CPP(
+ [GCC visibility push],
+ [ #include <cassert>
+ ],
+ [
+ AC_MSG_RESULT(yes)
+ kde_stdc_visibility_patched=yes ],
+ [
+ AC_MSG_RESULT(no)
+ AC_MSG_WARN([Your libstdc++ doesn't appear to be patched for
+ visibility support. Disabling -fvisibility=hidden])
+
+ kde_stdc_visibility_patched=no ])
+ AC_LANG_RESTORE
+
kde_have_gcc_visibility=no
- KDE_CHECK_COMPILER_FLAG(fvisibility=hidden,
- kde_have_gcc_visibility=yes
- CXXFLAGS="$CXXFLAGS -fvisibility=hidden"
- KDE_CHECK_VISIBILITY_GCC_BUG
- HAVE_GCC_VISIBILITY=1
- AC_DEFINE_UNQUOTED(__KDE_HAVE_GCC_VISIBILITY, "$HAVE_GCC_VISIBILITY", [define to 1 if -fvisibility is supported])
+
+ if test x$kde_stdc_visibility_patched = xyes ; then
+ KDE_CHECK_COMPILER_FLAG(fvisibility=hidden,
+ [
+ kde_have_gcc_visibility=yes
+ CXXFLAGS="$CXXFLAGS -fvisibility=hidden"
+ KDE_CHECK_VISIBILITY_GCC_BUG
+ HAVE_GCC_VISIBILITY=1
+ AC_DEFINE_UNQUOTED(__KDE_HAVE_GCC_VISIBILITY, "$HAVE_GCC_VISIBILITY", [define to 1 if -fvisibility is supported])
+ ])
+ fi
fi
BTW: I've rebuilt kdelibs with `--enable-gcc-hidden-visibility' and all seems well.
Tpowa: Thanks for looking into this