fd0e60530f
Test if ccache is interfering with semantic analysis of macros, disable its habit of trying to compile already pre-processed versions of code if so. ccache attempts to save time by compiling pre-processed versions of code, but this disturbs clang's static analysis enough to produce false positives. ccache allows us to disable this feature, opting instead to compile the original version instead of its preprocessed version. This makes ccache much slower for cache misses, but at least it becomes usable with QEMU/clang. This workaround only activates for users using ccache AND clang, and only if their configuration is observed to be producing warnings. You may need to clear your ccache for builds started without -Werror, as those may continue to produce warnings from the cache. Thanks to Peter Eisentraut for his writeup on the issue: http://peter.eisentraut.org/blog/2014/12/01/ccache-and-clang-part-3/ Signed-off-by: John Snow <jsnow@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-id: 1427324259-1481-5-git-send-email-jsnow@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Read the documentation in qemu-doc.html or on http://wiki.qemu-project.org - QEMU team