Re: [ccache] Why not cache link commands?

2012-09-19 Thread Andrew Stubbs
On 18/09/12 22:59, Mike Frysinger wrote: the linker's --build-id and associated .note.gnu.build-id section. you can't hash the entire object because it can change between compiles. build-id lets you say regardless of the hash of the entire object, we know the content that matters is unchanged.

Re: [ccache] Why not cache link commands?

2012-09-19 Thread Andrew Stubbs
On 19/09/12 13:18, Eitan Adler wrote: Under what circumstances can the binary change but the build-id remain the same? I'm aware of line number, and file path differences in the debug info. Is there anything else? differing -frandom-seed options perhaps? If you've changed the command line

Re: [ccache] Why not cache link commands?

2012-09-18 Thread Mike Frysinger
On Tuesday 18 September 2012 08:44:29 Andrew Stubbs wrote: Clearly there are some technical challenges in doing this: we'd have to hash all the object files and libraries (a la direct mode), but those problems are surmountable, I think. or just re-use build-id ... The linker does not use any

Re: [ccache] Why not cache link commands?

2012-09-18 Thread Mike Frysinger
On Tuesday 18 September 2012 17:07:53 Andrew Stubbs wrote: On 18/09/12 21:04, Mike Frysinger wrote: On Tuesday 18 September 2012 08:44:29 Andrew Stubbs wrote: Clearly there are some technical challenges in doing this: we'd have to hash all the object files and libraries (a la direct mode),