RFR: 8210647: libsaproc is being compiled without optimization.

[Severin Gehwolf]

Hi Thomas,

On Tue, 2018-09-18 at 11:08 +0200, Thomas Stüfe wrote:
> Hi Severin,
> 
> I get reproducable build errors with your fix on my machine (Ubuntu 16.4).
> 
> When I build release (no special build options), I get:
> 
> /shared/projects/openjdk/jdk-jdk/source/src/jdk.hotspot.agent/linux/native/libsaproc/ps_core.c:
> In function ‘read_exec_segments’:
> /shared/projects/openjdk/jdk-jdk/source/src/jdk.hotspot.agent/linux/native/libsaproc/ps_core.c:798:7:
> error: ignoring return value of ‘pread’, declared with attribute
> warn_unused_result [-Werror=unused-result]
>        pread(ph->core->exec_fd, interp_name, exec_php->p_filesz,
> exec_php->p_offset);
>        ^
> 
> When I remove your change (reset opt to NONE) error goes away. I have
> no idea why optimization influences warning level though. Any ideas?

It's rather strange, yes.

> (Of course, one could just fix the warning, but I wonder if I am the
> only one with this problem)

It's this (you are not the only one):
https://bugs.openjdk.java.net/browse/JDK-8210836

Would --disable-warnings-as-errors work for you?

We have to have this switched on for our distro builds, as there is
rarely a clean build unless you manage to have the blessed compiler
versions available, don't build with system libs, etc.

Sorry about this!

Cheers,
Severin

> Best Regards, Thomas
> 
> 
> 
> On Mon, Sep 17, 2018 at 6:25 AM, Sharath Ballal
> <sharath.ballal at oracle.com> wrote:
> > Hi Severin,
> > 
> > Looks good to me.
> > 
> > 
> > Thanks,
> > Sharath (not a Reviewer)
> > 
> > 
> > -----Original Message-----
> > From: Severin Gehwolf [mailto:sgehwolf at redhat.com]
> > Sent: Friday, September 14, 2018 7:04 PM
> > To: build-dev; serviceability-dev
> > Subject: RFR: 8210647: libsaproc is being compiled without optimization.
> > 
> > Hi,
> > 
> > Could I please get a review of this one-liner fix. It changes optimization of libsaproc from -O0 to -O3 (as per Magnus' suggestion).
> > I've run servicability tests and haven't seen any new failures.
> > Thoughts?
> > 
> > Bug: https://bugs.openjdk.java.net/browse/JDK-8210647
> > webrev: http://cr.openjdk.java.net/~sgehwolf/webrevs/JDK-8210647/webrev.01/
> > 
> > Thanks,
> > Severin
> > 
> >