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

[Yury Gribov <tetra2005.patches@gmail.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