On Sun, 2 Aug 2020 at 19:49, Christian Ledergerber via ccache <ccache@lists.samba.org> wrote: > In the mean-time I have been thinking some more and what I am afraid of > is that the result will not be correct if the flags to clang-tidy change. > > A typical command run by make looks like this: > > cd /home/dev/erx-soft/cmake-build-debug/modules/utils && ccache > /home/dev/clion-2020.1.3/bin/cmake/linux/bin/cmake -E __run_co_compile [...]
If I interpret the example command correctly ccache is used as a prefix to cmake? That won't have any effect; ccache can't cache the result of cmake so it will just fall back to executing cmake with the given arguments (and increase some statistics counter). > --launcher=ccache I guess this means that cmake will execute "ccache $compiler ..." later. > [...] In other words: it seems like ccache could also hash the flags to > clang-tidy. The question: does it? No, since ccache doesn't see any clang-tidy arguments when cmake executes "ccache $compiler ..." as mentioned above. > Now that I am looking at the above command line: Will this require to > also modify the cmake binary to generate other command lines? I have no idea, but it sounds likely. Here's an idea to consider: You could write the clang-tidy arguments to a file and set CCACHE_EXTRAFILES to the file. Or just set it to preexisting .clang-tidy files? Then the ccache results will be invalidated when the clang-tidy arguments change. That in combination with the hypothetical mode where ccache would exit with failure on a cache miss would maybe enough for your initial idea. -- Joel _______________________________________________ ccache mailing list ccache@lists.samba.org https://lists.samba.org/mailman/listinfo/ccache
