From 977a82ab56daac83623d730174f47d5a7edd73c9 Mon Sep 17 00:00:00 2001 From: "Daniel P. Berrange" Date: Wed, 27 Jan 2016 09:00:45 +0000 Subject: configure: sanity check the glib library that pkg-config finds MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Message-Id: <1453885245-15562-1-git-send-email-berrange@redhat.com> Signed-off-by: Paolo Bonzini --- configure | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) (limited to 'configure') diff --git a/configure b/configure index d4411a1314..c9cf1c91f5 100755 --- a/configure +++ b/configure @@ -3063,6 +3063,30 @@ 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 < +#include + +#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 -- cgit v1.2.1