Re: [PING^4][PATCH v2] Generate reproducible output independently of the build-path

[Yury Gribov <tetra2005 dot patches at gmail dot com>]

On 03.08.2017 3:06, Ximin Luo wrote:
> Jeff Law:
> > On 07/21/2017 10:15 AM, Ximin Luo wrote:
> > > (Please keep me on CC, I am not subscribed)
> > >
> > >
> > > Proposal
> > > ========
> > >
> > > This patch series adds a new environment variable BUILD_PATH_PREFIX_MAP. When
> > > this is set, GCC will treat this as extra implicit "-fdebug-prefix-map=$value"
> > > command-line arguments that precede any explicit ones. This makes the final
> > > binary output reproducible, and also hides the unreproducible value (the source
> > > path prefixes) from CFLAGS et. al. which many build tools (understandably)
> > > embed as-is into their build output.
> > I'd *really* avoid doing this with magic environment variables.  Make it
> > a first class option to the compiler.  Yes, it means projects that want
> > this behavior have to arrange to pass that flag to their compiler, but
> > IMHO that's much preferred over environment variables.
> >
> > Jeff
>
> Hi Jeff,
>
> If by "first class option" you meant a command-line flag, GCC *already has* that (-fdebug-prefix-map) > and it wasn't enough to achieve reproducibility in many cases we tested.

Shouldn't -fdebug-prefix-map be updated to use the same syntax as 
BUILD_PATH_PREFIX_MAP?

-Y