[PATCH] (Title Corrected) Build fails to compile jchuff.c using gcc 4.8.5 on zLinux

[David Holmes]

Adam,

Erik or Magnus from the build team should step in here if this 
information is wrong but AFAIK the intent is that using the official 
toolchains the OpenJDK will build out-of-the-box using the supplied 
instructions and whatever the default settings are (which ideally would 
be without any warnings).

Anyone building with a different toolchain may encounter problems, and 
may need to disable warnings-as-errors. That should be in the build docs 
somewhere if it isn't now.

The build wiki has unfortunately not been updated for JDK 10, but we 
didn't make any changes to the official toolchains compared to JDK 9:

https://wiki.openjdk.java.net/display/Build/Supported+Build+Platforms

As gcc 4.8.5 is listed as an "other build platform" I would not have 
expected you to encounter this problem. Though it is not stated on the 
wiki whether building on these other platforms requires changing any of 
the build settings.

If an official, or even semi-official, toolchain encounters a problem 
then we may look into adding a toolchain specific workaround for the 
specific file(s) affected (ie disable the specific warning). Otherwise, 
as "John" (aka Adrian) states we don't play this game for every possible 
toolchain that may be used.

David

On 17/01/2018 10:56 PM, Adam Farley8 wrote:
> Hi John, David,
> 
>>> If you compile jchuff.c  (part of javajpeg) without
>>> "--disable-warnings-as-errors",
>>> then you get an error that kills the build. This is seen in these
>>> circumstances:
> 
>>Last time this particular discussion came up, the conclusion was that
>>hunting for warnings is a lost battle as the generated warnings depend
>>heavily on the toolchain used [1,2].
> 
>>So, I think for now we're not going to address build errors which occur
>>when omitting "--disable-warnings-as-errors" in the configure  line.
> 
> If this is the consensus, then perhaps we should consider setting
> --disable-warnings-as-errors by default (in the code), rather than
> depending on the user using an option which is not part of the formal
> build instructions.
> 
> Thoughts?
> 
> Best Regards
> 
> Adam Farley
> 
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