Re: Debugging why Build Rebuilds Something

["Cohen, Eugene" <eugene@hp.com>]

Liming - thank you - this technique of diff'ing the Makefiles immediately identified the issue.

We were defining an environment variable that contained date/time values that was used in tools_def resulting in all this unnecessary rebuild behavior.

Thanks a ton!

Eugene

From: Cohen, Eugene
Sent: Thursday, March 21, 2019 4:15 AM
To: 'Gao, Liming' <liming.gao@intel.com>; edk2-devel@lists.01.org
Subject: RE: Debugging why Build Rebuilds Something

Great - I will try this now, thanks Liming!

From: Gao, Liming <liming.gao@intel.com<mailto:liming.gao@intel.com>>
Sent: Thursday, March 21, 2019 4:02 AM
To: Cohen, Eugene <eugene@hp.com<mailto:eugene@hp.com>>; edk2-devel@lists.01.org<mailto:edk2-devel@lists.01.org>
Subject: RE: Debugging why Build Rebuilds Something

Could you help check the timestamp of AutoGen files in OpenSslLib output directory?

After the first build, copy OpenSslLib output directory to another directory
After the second build, compare the output directory between two builds, please check whether there is the difference for AutoGen.h and Makefile. If no difference, please directly trig Makefile to see whether rebuild happen. If rebuild happen, it may be the issue in Makefile. Then, further check Makefile.

Thanks
Liming
>-----Original Message-----
>From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of
>Cohen, Eugene
>Sent: Thursday, March 21, 2019 5:50 PM
>To: edk2-devel@lists.01.org<mailto:edk2-devel@lists.01.org>
>Subject: [edk2] Debugging why Build Rebuilds Something
>
>I'm experiencing an annoying problem where OpenSslLib is constantly being
>rebuilt. I don't think I've done anything unusual or different to it but
>nevertheless it gets built almost every time I rebuild the same platform.
>
>I don't believe any source file timestamps are changing so I think this may be
>the build.py tool deciding to re-generate stuff. (As a side note: does the
>Autogen process only run when changes are detected on dependencies? I
>assume this must be the case otherwise everything would get rebuilt, right?)
>
>Is there a debug flag that can be turned on to see why build might choose to
>rebuild something? The normal build report and debug flags don't see to
>provide the information for "why" something is being rebuilt.
>
>Thanks,
>
>Eugene
>
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