On Mon, Jul 28, 2014 at 11:48:58AM -0700, Cary Coutant wrote: > > + /* ??? MD5 of another hash doesn't make a lot of sense... */ > > + hash = hstate.end(); > > CHECKSUM (hash); > > [citation needed] I don't see why you think that. Maybe it'd be nicer > if we could use hash_loc_operands() to feed its input directly into > the MD5 checksum, but I think in this case it's perfectly fine to use > the hash instead, in order to avoid reimplementing a rather > substantial function that already exists.
Well you're dropping information at least, and it's slower than it could be. > Maybe we could make hash_loc_operands() a template that can be used as > part of either inchash or MD5? > > In the case of loc_checksum(), we're tied to MD5 by the DWARF > standard. Otherwise, we could just rewrite it to use inchash > throughout. I'm not sure I understand the motivation. If gcc hashes in gcc specific stuff (and this hash, even before my changes is) then the output can never be re-created by anything but gcc. If the standard just wants a well hashed number at the end then any good hash should do. I haven't checked it for this case, but if the hashing shows up in profiles it may be worth using a faster but non secure hash. Anyways I can drop the comment if you don't agree with it. -Andi
