RFR: 8234535: Cross compilation fails due to missing CFLAGS for the BUILD_CC

[christoph.goettschkes at microdoc.com]

Hi Erik,

thanks for looking into this. I created a new webrev which includes the 
changeset and you as a reviewer:

http://cr.openjdk.java.net/~cgo/8234535/webrev.02/

Could you please sponsor this changeset and commit it into the repository 
for me?

Thanks,
Christoph

Erik Joelsson <erik.joelsson at oracle.com> wrote on 2019-11-22 17:19:08:

> From: Erik Joelsson <erik.joelsson at oracle.com>
> To: christoph.goettschkes at microdoc.com, build-dev at openjdk.java.net
> Date: 2019-11-22 17:19
> Subject: Re: RFR: 8234535: Cross compilation fails due to missing 
> CFLAGS for the BUILD_CC
> 
> Hello Christoph,
> 
> On 2019-11-20 10:22, christoph.goettschkes at microdoc.com wrote:
> > Hi,
> >
> > please review the following change.
> >
> > Bug: https://bugs.openjdk.java.net/browse/JDK-8234535
> > Webrev: https://cr.openjdk.java.net/~cgo/8234535/webrev.00/
> >
> > The removed lines are completely out of place and have no use at all. 
for
> > the CC variable, for instance, the script does the following:
> >
> > CC_OLD="$CC"
> > CC="$BUILD_CC"
> > CC="$CC_OLD"
> >
> > without executing any function between those lines. I think that, 
while
> > restructuring the build system, those lines have been copied to the 
wrong
> > location. I copied them around the "FLAGS_SETUP_CFLAGS_CPU_DEP" call 
for
> > the BUILD_CC, in order to make configure not use the target CFLAGS 
while
> > discovering possible CFLAGS for the BUILD_CC, which was happening in 
our
> > case.
> Wow, I had not noticed that. Your fix looks correct.
> > I am also not sure if the variable BUILD_CC_DISABLE_WARNING_PREFIX is
> > actually used anywhere. I could not find any user and it might be 
possible
> > to simply remove it.
> It's used to override DISABLE_WARNING_PREFIX in buildjdk-spec.gmk so I 
> think it serves a purpose, even if we don't actually support different 
> toolchain types for cross and native compiler. If we ever will, then 
> this variable will be needed, so I think it should stay.
> > I tried the change and compiled on an amd64 linux machine for amd64, 
and
> > cross-compiled for linux on armv7 and linux on aarch64. I don't have
> > access to other cross-compilation environments and would like to ask
> > others to review and try out the change.
> 
> I applied the patch and tried a few of our configurations. Since we use 
> the same (or close to the same) compiler versions across architectures, 
> I don't actually see any difference in the generated spec files. The 
> reason you see this is the large version difference between your 
compilers.
> 
> Looks good, thanks for finding and fixing this!
> 
> /Erik
> 
> > Thanks,
> > Christoph
> >
>