| Message ID | 1453885245-15562-1-git-send-email-berrange@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 27/01/2016 10:00, Daniel P. Berrange wrote: > Developers on 64-bit machines will often try to perform a > 32-bit build of QEMU by running > > ./configure --extra-cflags="-m32" > > Unfortunately if PKG_CONFIG_LIBDIR is not set to point to > the location of the 32-bit pkg-config files, then configure > will silently pick up the 64-bit pkg-config files and still > succeed. > > This causes a problem for glib because it means QEMU will > be pulling in /usr/lib64/glib-2.0/include/glibconfig.h > instead of /usr/lib/glib-2.0/include/glibconfig.h > > This causes problems because the 'gsize' type (defined as > 'unsigned long') will no longer be fully compatible with > the 'size_t' type (defined as 'unsigned int'). Although > both are the same size, the compiler refuses to allow > casts from 'unsigned long *' to 'unsigned int *' as they > are different pointer types. This results in non-obvious > compiler errors when building QEMU eg > > qga/commands-posix.c: In function ‘qmp_guest_set_user_password’: > qga/commands-posix.c:1912:55: error: passing argument 2 of ‘g_base64_decode’ from incompatible pointer type [-Werror=incompatible-pointer-types] > rawpasswddata = (char *)g_base64_decode(password, &rawpasswdlen); > ^ > In file included from /usr/include/glib-2.0/glib.h:35:0, > from qga/commands-posix.c:14: > /usr/include/glib-2.0/glib/gbase64.h:52:9: note: expected ‘gsize * {aka long unsigned int *}’ but argument is of type ‘size_t * {aka unsigned int *}’ > guchar *g_base64_decode (const gchar *text, > ^ > cc1: all warnings being treated as errors > > To detect this problem, add a check to configure that > verifies that GLIB_SIZEOF_SIZE_T matches sizeof(size_t). > If this fails print a warning suggesting that the dev > probably needs to set PKG_CONFIG_LIBDIR. > > On Fedora x86_64 it passes with any of: > > # ./configure > # PKG_CONFIG_LIBDIR=/usr/lib/pkgconfig ./configure --extra-cflags="-m32" > # PKG_CONFIG_LIBDIR=/usr/lib64/pkgconfig ./configure --extra-cflags="-m64" > > And fails with a mis-match > > # PKG_CONFIG_LIBDIR=/usr/lib64/pkgconfig ./configure --extra-cflags="-m32" > # PKG_CONFIG_LIBDIR=/usr/lib/pkgconfig ./configure --extra-cflags="-m64" > > ERROR: sizeof(size_t) doesn't match GLIB_SIZEOF_SIZE_T. > You probably need to set PKG_CONFIG_LIBDIR > to point to the right pkg-config files for your > build target > > Signed-off-by: Daniel P. Berrange <berrange@redhat.com> > --- > > Changed in v3: > > - Removed use of G_STATIC_ASSERT in favour of simplified > version of QEMU_BUILD_BUG_ON to avoid unused typedef > warning > > configure | 24 ++++++++++++++++++++++++ > 1 file changed, 24 insertions(+) > > diff --git a/configure b/configure > index 44ac9ab..fbd2482 100755 > --- a/configure > +++ b/configure > @@ -2997,6 +2997,30 @@ for i in $glib_modules; do > fi > done > > +# Sanity check that the current size_t matches the > +# size that glib thinks it should be. This catches > +# problems on multi-arch where people try to build > +# 32-bit QEMU while pointing at 64-bit glib headers > +cat > $TMPC <<EOF > +#include <glib.h> > +#include <unistd.h> > + > +#define QEMU_BUILD_BUG_ON(x) \ > + typedef char qemu_build_bug_on[(x)?-1:1] __attribute__((unused)); > + > +int main(void) { > + QEMU_BUILD_BUG_ON(sizeof(size_t) != GLIB_SIZEOF_SIZE_T); > + return 0; > +} > +EOF > + > +if ! compile_prog "-Werror $CFLAGS" "$LIBS" ; then > + error_exit "sizeof(size_t) doesn't match GLIB_SIZEOF_SIZE_T."\ > + "You probably need to set PKG_CONFIG_LIBDIR"\ > + "to point to the right pkg-config files for your"\ > + "build target" > +fi > + > # g_test_trap_subprocess added in 2.38. Used by some tests. > glib_subprocess=yes > if ! $pkg_config --atleast-version=2.38 glib-2.0; then > Queued, thanks. Paolo
diff --git a/configure b/configure index 44ac9ab..fbd2482 100755 --- a/configure +++ b/configure @@ -2997,6 +2997,30 @@ for i in $glib_modules; do fi done +# Sanity check that the current size_t matches the +# size that glib thinks it should be. This catches +# problems on multi-arch where people try to build +# 32-bit QEMU while pointing at 64-bit glib headers +cat > $TMPC <<EOF +#include <glib.h> +#include <unistd.h> + +#define QEMU_BUILD_BUG_ON(x) \ + typedef char qemu_build_bug_on[(x)?-1:1] __attribute__((unused)); + +int main(void) { + QEMU_BUILD_BUG_ON(sizeof(size_t) != GLIB_SIZEOF_SIZE_T); + return 0; +} +EOF + +if ! compile_prog "-Werror $CFLAGS" "$LIBS" ; then + error_exit "sizeof(size_t) doesn't match GLIB_SIZEOF_SIZE_T."\ + "You probably need to set PKG_CONFIG_LIBDIR"\ + "to point to the right pkg-config files for your"\ + "build target" +fi + # g_test_trap_subprocess added in 2.38. Used by some tests. glib_subprocess=yes if ! $pkg_config --atleast-version=2.38 glib-2.0; then
Developers on 64-bit machines will often try to perform a 32-bit build of QEMU by running ./configure --extra-cflags="-m32" Unfortunately if PKG_CONFIG_LIBDIR is not set to point to the location of the 32-bit pkg-config files, then configure will silently pick up the 64-bit pkg-config files and still succeed. This causes a problem for glib because it means QEMU will be pulling in /usr/lib64/glib-2.0/include/glibconfig.h instead of /usr/lib/glib-2.0/include/glibconfig.h This causes problems because the 'gsize' type (defined as 'unsigned long') will no longer be fully compatible with the 'size_t' type (defined as 'unsigned int'). Although both are the same size, the compiler refuses to allow casts from 'unsigned long *' to 'unsigned int *' as they are different pointer types. This results in non-obvious compiler errors when building QEMU eg qga/commands-posix.c: In function ‘qmp_guest_set_user_password’: qga/commands-posix.c:1912:55: error: passing argument 2 of ‘g_base64_decode’ from incompatible pointer type [-Werror=incompatible-pointer-types] rawpasswddata = (char *)g_base64_decode(password, &rawpasswdlen); ^ In file included from /usr/include/glib-2.0/glib.h:35:0, from qga/commands-posix.c:14: /usr/include/glib-2.0/glib/gbase64.h:52:9: note: expected ‘gsize * {aka long unsigned int *}’ but argument is of type ‘size_t * {aka unsigned int *}’ guchar *g_base64_decode (const gchar *text, ^ cc1: all warnings being treated as errors To detect this problem, add a check to configure that verifies that GLIB_SIZEOF_SIZE_T matches sizeof(size_t). If this fails print a warning suggesting that the dev probably needs to set PKG_CONFIG_LIBDIR. On Fedora x86_64 it passes with any of: # ./configure # PKG_CONFIG_LIBDIR=/usr/lib/pkgconfig ./configure --extra-cflags="-m32" # PKG_CONFIG_LIBDIR=/usr/lib64/pkgconfig ./configure --extra-cflags="-m64" And fails with a mis-match # PKG_CONFIG_LIBDIR=/usr/lib64/pkgconfig ./configure --extra-cflags="-m32" # PKG_CONFIG_LIBDIR=/usr/lib/pkgconfig ./configure --extra-cflags="-m64" ERROR: sizeof(size_t) doesn't match GLIB_SIZEOF_SIZE_T. You probably need to set PKG_CONFIG_LIBDIR to point to the right pkg-config files for your build target Signed-off-by: Daniel P. Berrange <berrange@redhat.com> --- Changed in v3: - Removed use of G_STATIC_ASSERT in favour of simplified version of QEMU_BUILD_BUG_ON to avoid unused typedef warning configure | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+)