[8u] RFR (S) 8079891: Store configure log in $BUILD/configure.log

[Aleksey Shipilev]

On 7/6/21 7:39 PM, Andrew Hughes wrote:
> It's not clear to me what this does.
> 
> Prior to this patch, I had a config.log in my build directory.

Yes, in the `pwd`:

jdk8u-dev $ find | grep config.log
./config.log

That one contains the messages that compilers produce when running ./configure.

> After this patch, I have both config.log and configure.log.old, which
> seems to contain largely the same information.
> 
> I don't see a configure.log.

It should be in per-config dir, and it contains the ./configure log, the same that you normally see 
in console, including configure warnings, etc.

jdk8u-dev $ find | grep configure.log
./build/linux-x86_64-normal-server-fastdebug/configure.log

It is symmetrical to the already existing build.log that captures the build output that you normally 
see in console as well.

jdk8u-dev $ find | grep build.log
./build/linux-x86_64-normal-server-fastdebug/build.log

> So what exactly is the problem we're trying to solve?

Exactly those logs are useful to see what is being built. Capturing them is a hassle, though.

Capturing ./configure output from stdout is doable, until you get into exit code handling, which is 
quite a mess (i.e. capturing the error code from the piped commands is sane mostly when forcing 
bash-isms like "set -o pipefail"). Configure output saved as file is significantly easier to deal with.

This backport helps at least my CIs to capture configure logs for jdk8u, as it is done for every 
other release already:
   https://builds.shipilev.net/openjdk-jdk8-dev/configure-logs/
   https://builds.shipilev.net/openjdk-jdk/configure-logs/

-- 
Thanks,
-Aleksey