On 08/02/2017 10:47 PM, Yury Gribov wrote: > 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? Or a different option to cover what Ximin is trying to do with BUILD_PATH_PREFIX_MAP. BUILD_PATH_PREFIX_MAP has to go, I'm not going to approve it in that form. But I would seriously consider the same functionality as a command line switch.
jeff
