On 12/09/13 08:22, Paolo Bonzini wrote:
Il 09/12/2013 13:47, Don Slutz ha scritto:
On 12/05/13 22:20, Don Slutz wrote:
On 12/05/13 16:24, Richard Henderson wrote:
On 12/06/2013 04:18 AM, Paolo Bonzini wrote:
$ gcc -shared -o f.so f.c -fPIE -fPIC
/usr/bin/ld: /tmp/ccQc9els.o: relocation R_X86_64_PC32 against `f'
can not be used when making a shared object; recompile with -fPIC
/usr/bin/ld: final link failed: Bad value
collect2: ld returned 1 exit status
The bug is simply that "-fPIE -fPIC" counts as -fPIE rather than -fPIC:
$ gcc -S -o - f.c -fPIE |grep call
call f # PC32 relocation
$ gcc -S -o - f.c -fPIC |grep call
call f@PLT # PLT32 relocation
The easy workaround is to drop -fPIE when we're adding -fPIC.
r~
[snip]
Attached is a much better version. It drops -fPIE and adds -fPIC for
libtool.
It's not much better, because using position-independent code for shared
libraries is really platform-dependent knowledge of the kind that
libtool is supposed to hide.
For example, on Mac OS X everything is position-independent by default.
And on some platforms you have -fpic instead of -fPIC.
So I prefer the patch you had that disabled libtool if the platform is
buggy.
Paolo
Well, the detection code is too simple:
FC17 system:
dcs-xen-52:~/tmp/libtool>uname -a
Linux dcs-xen-52 3.8.11-100.fc17.x86_64 #1 SMP Wed May 1 19:31:26
UTC 2013 x86_64 x86_64 x86_64 GNU/Linux
dcs-xen-52:~/tmp/libtool>gcc -shared -fPIE -DPIE f.c -fPIC -DPIC -o f.so
/usr/bin/ld: /tmp/ccl4By1r.o: relocation R_X86_64_PC32 against
symbol `f' can not be used when making a shared object; recompile
with -fPIC
/usr/bin/ld: final link failed: Bad value
collect2: error: ld returned 1 exit status
dcs-xen-52:~/tmp/libtool>libtool --mode=compile gcc -g -c -fPIE
-DPIE f.c
libtool: compile: gcc -g -c -DPIE f.c -fPIC -DPIC -o .libs/f.o
libtool: compile: gcc -g -c -DPIE f.c -fPIE -o f.o >/dev/null 2>&1
dcs-xen-52:~/tmp/libtool>libtool --mode=link gcc -g -o libf.la f.lo
-rpath /usr/local/lib
libtool: link: gcc -shared -fPIC -DPIC .libs/f.o -Wl,-soname
-Wl,libf.so.0 -o .libs/libf.so.0.0.0
libtool: link: (cd ".libs" && rm -f "libf.so.0" && ln -s
"libf.so.0.0.0" "libf.so.0")
libtool: link: (cd ".libs" && rm -f "libf.so" && ln -s
"libf.so.0.0.0" "libf.so")
libtool: link: ar cru .libs/libf.a f.o
libtool: link: ranlib .libs/libf.a
libtool: link: ( cd ".libs" && rm -f "libf.la" && ln -s "../libf.la"
"libf.la" )
CentOS 5.10:
dcs-xen-53:~/tmp/libtool>uname -a
Linux dcs-xen-53 2.6.18-371.el5xen #1 SMP Tue Oct 1 09:15:30 EDT
2013 x86_64 x86_64 x86_64 GNU/Linux
dcs-xen-53:~/tmp/libtool>gcc -shared -fPIE -DPIE f.c -fPIC -DPIC -o f.so
/usr/bin/ld: /tmp/ccAy1vZK.o: relocation R_X86_64_PC32 against `f'
can not be used when making a shared object; recompile with -fPIC
/usr/bin/ld: final link failed: Bad value
collect2: ld returned 1 exit status
dcs-xen-53:~/tmp/libtool>libtool --mode=compile gcc -g -c -fPIE
-DPIE f.c
mkdir .libs
gcc -g -c -fPIE -DPIE f.c -fPIC -DPIC -o .libs/f.o
gcc -g -c -fPIE -DPIE f.c -o f.o >/dev/null 2>&1
dcs-xen-53:~/tmp/libtool>libtool --mode=link gcc -g -o libf.la f.lo
-rpath /usr/local/lib
gcc -shared .libs/f.o -Wl,-soname -Wl,libf.so.0 -o
.libs/libf.so.0.0.0
/usr/bin/ld: .libs/f.o: relocation R_X86_64_PC32 against `f' can not
be used when making a shared object; recompile with -fPIC
/usr/bin/ld: final link failed: Bad value
collect2: ld returned 1 exit status
I have attached a patch that uses libtool to determine if gcc & libtool
is broken.
-Don
>From 4653e3e4df6abd55adb70b97cd8c7b1b10933a42 Mon Sep 17 00:00:00 2001
From: Don Slutz <dsl...@verizon.com>
Date: Sat, 14 Dec 2013 19:43:56 +0000
Subject: [PATCH] configure: Disable libtool if -fPIE does not work with it
(bug #1257099)
Adjust TMPO and added TMPB, TMPL, and TMPA. libtool needs the names to be fixed (TMPB).
Add new functions do_libtool and libtool_prog.
Add check for broken gcc and libtool.
Signed-off-by: Don Slutz <dsl...@verizon.com>
---
configure | 63 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 62 insertions(+), 1 deletion(-)
diff --git a/configure b/configure
index 0666228..ead34ae 100755
--- a/configure
+++ b/configure
@@ -12,7 +12,10 @@ else
fi
TMPC="${TMPDIR1}/qemu-conf-${RANDOM}-$$-${RANDOM}.c"
-TMPO="${TMPDIR1}/qemu-conf-${RANDOM}-$$-${RANDOM}.o"
+TMPB="qemu-conf-${RANDOM}-$$-${RANDOM}"
+TMPO="${TMPDIR1}/${TMPB}.o"
+TMPL="${TMPDIR1}/${TMPB}.lo"
+TMPA="${TMPDIR1}/lib${TMPB}.la"
TMPE="${TMPDIR1}/qemu-conf-${RANDOM}-$$-${RANDOM}.exe"
# NB: do not call "exit" in the trap handler; this is buggy with some shells;
@@ -86,6 +89,38 @@ compile_prog() {
do_cc $QEMU_CFLAGS $local_cflags -o $TMPE $TMPC $LDFLAGS $local_ldflags
}
+do_libtool() {
+ local mode=$1
+ shift
+ # Run the compiler, capturing its output to the log.
+ echo $libtool $mode --tag=CC $cc "$@" >> config.log
+ $libtool $mode --tag=CC $cc "$@" >> config.log 2>&1 || return $?
+ # Test passed. If this is an --enable-werror build, rerun
+ # the test with -Werror and bail out if it fails. This
+ # makes warning-generating-errors in configure test code
+ # obvious to developers.
+ if test "$werror" != "yes"; then
+ return 0
+ fi
+ # Don't bother rerunning the compile if we were already using -Werror
+ case "$*" in
+ *-Werror*)
+ return 0
+ ;;
+ esac
+ echo $libtool $mode --tag=CC $cc -Werror "$@" >> config.log
+ $libtool $mode --tag=CC $cc -Werror "$@" >> config.log 2>&1 && return $?
+ error_exit "configure test passed without -Werror but failed with -Werror." \
+ "This is probably a bug in the configure script. The failing command" \
+ "will be at the bottom of config.log." \
+ "You can run configure with --disable-werror to bypass this check."
+}
+
+libtool_prog() {
+ do_libtool --mode=compile $QEMU_CFLAGS -c -fPIE -DPIE -o $TMPO $TMPC || return $?
+ do_libtool --mode=link $LDFLAGS -o $TMPA $TMPL -rpath /usr/local/lib
+}
+
# symbolically link $1 to $2. Portable version of "ln -sf".
symlink() {
rm -rf "$2"
@@ -1328,6 +1363,32 @@ if test "$pie" = ""; then
esac
fi
+# check for broken gcc and libtool in RHEL5
+if test -n "$libtool" -a "$pie" != "no" ; then
+ cat > $TMPC <<EOF
+
+void *f(unsigned char *buf, int len);
+void *g(unsigned char *buf, int len);
+
+void *
+f(unsigned char *buf, int len)
+{
+ return (void*)0L;
+}
+
+void *
+g(unsigned char *buf, int len)
+{
+ return f(buf, len);
+}
+
+EOF
+ if ! libtool_prog; then
+ echo "Disabling libtool due to broken toolchain support"
+ libtool=
+ fi
+fi
+
if test "$pie" != "no" ; then
cat > $TMPC << EOF
--
1.8.2.1
