On 11/08/2011 01:49 PM, Joel Rosdahl wrote:
On 5 November 2011 01:26, Frank Klotz<frank.kl...@alcatel-lucent.com> wrote:
[...] I remember quite clearly (and I just confirmed with a colleague who is
still there) that the file names in the cache contained BOTH the hash AND the
basename of the object file.
As far as I know, the object files have always been stored using only the hash.
However, temporary files (stored in $CCACHE_DIR in ccache<=2.4 and
$CCACHE_DIR/tmp in ccache>=3.0) include (a prefix of) the basename.
[...] (and another string that the ccache code refers to as "size", although
I can't quite figure out what it's the size OF)
It's the size of the hashed text, i.e. output from the preprocessor. This is
just a way of making filename collisions somewhat less likely.
One place we found the basenames invaluable was tracking down a corrupted
object file in the cache. Once we confirmed that we had a corrupt object file
foo.o, we simple searched for all "*foo.o" files in the cache, compared those
in size and content to an actual corrupted object file in the user directory,
and easily removed the corrupted file from the cache. Much harder (not
impossible, but harder) to do this without the basenames.
An easy way to do that is:
1. Remove foo.o from the build tree.
2. Build with CCACHE_LOGFILE set to a log file.
3. Look for "Created foo.o from X" (where X is a file in the cache) in the log
file.
4. Remove X.
Or even easier:
Suggestion: Put the below 2-line solution in the "Corrupt object files"
section of
http://ccache.samba.org/manual.html
1. Remove foo.o from the build tree.
2. Build with CCACHE_RECACHE set.
It's a LOT lighter-weight solution than clearing the cache, and much
easier than messing with the log.
Thanks,
Frank
[...] Anyway, is there a general consensus on whether this would be valuable?
It doesn't sound like a good idea to me, at least, since you would need to
store duplicate copies of the object file for two compilations where the source
content is the same but the file names differ.
-- Joel
_______________________________________________
ccache mailing list
ccache@lists.samba.org
https://lists.samba.org/mailman/listinfo/ccache
