On 2016/11/30 22:49, Jiri Olsa wrote:
On Tue, Nov 29, 2016 at 02:31:36PM +0100, Jiri Olsa wrote:
hi,
we noticed behaviour change in Fedora 25 gcc wrt -Wp option.
We use following command line to generate the dependency file:
gcc -Wp,-MD,krava,-MT,krava -c -o ex.o ex.c
and we get 'krava' file with:
krava: ex.c /usr/include/stdc-predef.h /usr/include/stdio.h \
But when we split -Wp option into 2 -Wp options like:
gcc -Wp,-MD,krava -Wp,MT,krava -c -o ex.o ex.c
we get:
ex.o krava: ex.c /usr/include/stdc-predef.h /usr/include/stdio.h \
notice the extra 'ex.o' target.
We see this behaviour in Fedora 25. It's ok in Fedora 24, which seems odd
because both have same gcc version 6.2.1. Please check full output below.
more info on this.. it's not fedora version related, it's related
to having ccache installed (kudos to Arnaldo ;-) )
with ccache installed above behaviour happens in both Fedora 24 and 25
Find in ccache releasenotes (https://ccache.samba.org/releasenotes.html)
ccache 3.3.2
Release date: 2016-09-28
Bug fixes
Fixed a regression in ccache 3.3 related to potentially bad content of
dependency files when compiling identical source code but with different
source paths.
Fixed a regression in ccache 3.3.1: ccache could get confused when using
the compiler option -Wp, to pass multiple options to the preprocessor,
resulting in missing dependency files from direct mode cache hits.
So please try a newer ccache and see the result?
thanks,
jirka
