On 06/12/2023 8:52 am, Jan Beulich wrote: > On 05.12.2023 19:32, Julien Grall wrote: >> From: Julien Grall <jgr...@amazon.com> >> >> Right now, all tools and hypervisor will be complied with the option >> -Wdeclaration-after-statement. While most of the code in the hypervisor >> is controlled by us, for tools we may import external libraries. >> >> The build will fail if one of them are using the construct we are >> trying to prevent. This is the case when building against Python 3.12 >> and Yocto: >> >> | In file included from >> /srv/storage/alex/yocto/build-virt/tmp/work/core2-64-poky-linux/xen-tools/4.17+stable/recipe-sysroot/usr/include/python3.12/Python.h:44, >> | from xen/lowlevel/xc/xc.c:8: >> | >> /srv/storage/alex/yocto/build-virt/tmp/work/core2-64-poky-linux/xen-tools/4.17+stable/recipe-sysroot/usr/include/python3.12/object.h: >> In function 'Py_SIZE': >> | >> /srv/storage/alex/yocto/build-virt/tmp/work/core2-64-poky-linux/xen-tools/4.17+stable/recipe-sysroot/usr/include/python3.12/object.h:233:5: >> error: ISO C90 forbids mixed declarations and code >> [-Werror=declaration-after-statement] >> | 233 | PyVarObject *var_ob = _PyVarObject_CAST(ob); >> | | ^~~~~~~~~~~ >> | In file included from >> /srv/storage/alex/yocto/build-virt/tmp/work/core2-64-poky-linux/xen-tools/4.17+stable/recipe-sysroot/usr/include/python3.12/Python.h:53: >> | >> /srv/storage/alex/yocto/build-virt/tmp/work/core2-64-poky-linux/xen-tools/4.17+stable/recipe-sysroot/usr/include/python3.12/cpython/longintrepr.h: >> In function '_PyLong_CompactValue': >> | >> /srv/storage/alex/yocto/build-virt/tmp/work/core2-64-poky-linux/xen-tools/4.17+stable/recipe-sysroot/usr/include/python3.12/cpython/longintrepr.h:121:5: >> error: ISO C90 forbids mixed declarations and code >> [-Werror=declaration-after-statement] >> | 121 | Py_ssize_t sign = 1 - (op->long_value.lv_tag & >> _PyLong_SIGN_MASK); >> | | ^~~~~~~~~~ >> | cc1: all warnings being treated as errors >> >> Looking at the tools directory, a fair few directory already add >> -Wno-declaration-after-statement to inhibit the default behavior. >> >> We have always build the hypervisor with the flag, so for now remove >> only the flag for anything but the hypervisor. We can decide at later >> time whether we want to relax. >> >> Also remove the -Wno-declaration-after-statement in some subdirectory >> as the flag is now unnecessary. > With all these removals, don't you need to add the option centrally > somewhere? Or else are you sure that no compiler version, including > distro-customized ones, would ever come with the warning enabled by > default?
declaration-after-statement being permitted is covered by the -std we choose. No distro is plausibly going to ship a compiler which takes -std=gnu99 and has declaration-after-statement forced off if in that configuration. ~Andrew
