gcc 7.3.1 build - warnings as errors in harfbuzz

[Baesken, Matthias]

Thanks.
I am a bit worried that

DISABLED_WARNINGS_gcc := format-truncation
DISABLED_WARNINGS_CXX_gcc := format-truncation  


Could bring errors on older gcc versions , any ideas about this ?
(will test with gcc 4.8 of course as well )

Best regards, Matthias



> -----Original Message-----
> From: Erik Joelsson <erik.joelsson at oracle.com>
> Sent: Mittwoch, 10. Oktober 2018 18:08
> To: Baesken, Matthias <matthias.baesken at sap.com>; 'build-
> dev at openjdk.java.net' <build-dev at openjdk.java.net>
> Subject: Re: gcc 7.3.1 build - warnings as errors in harfbuzz
> 
> I think that's fine. This is the granularity we have.
> 
> /Erik
> 
> 
> On 2018-10-10 09:02, Baesken, Matthias wrote:
> > Hi Erik,  so I think I could disable  the warning here :
> >
> >
> > Awt2dLibraries.gmk
> > ---------------------------------
> >
> > $(eval $(call SetupJdkLibrary, BUILD_LIBFONTMANAGER, \
> >      NAME := fontmanager, \
> >    ....
> >      WARNINGS_AS_ERRORS_xlc := false, \
> >      DISABLED_WARNINGS_gcc := format-truncation sign-compare int-to-
> pointer-cast \
> >          type-limits missing-field-initializers implicit-fallthrough \
> >          strict-aliasing undef unused-function, \
> >      DISABLED_WARNINGS_CXX_gcc := format-truncation  reorder delete-
> non-virtual-dtor strict-overflow \
> >          maybe-uninitialized, \
> >   ...
> >
> > (add   format-truncation    for gcc in the  warning-disabling section).
> > However this would disable it also for other versions of gcc  where the
> issue never showed up .
> >
> > Do you think this is fine  (and safe for older gcc) ?
> >
> >
> > Best regards, Matthias
> >
> >> -----Original Message-----
> >> From: Erik Joelsson <erik.joelsson at oracle.com>
> >> Sent: Mittwoch, 10. Oktober 2018 17:33
> >> To: Baesken, Matthias <matthias.baesken at sap.com>; 'build-
> >> dev at openjdk.java.net' <build-dev at openjdk.java.net>
> >> Subject: Re: gcc 7.3.1 build - warnings as errors in harfbuzz
> >>
> >> In this case, disabling the warning seems like the right thing to do.
> >>
> >> /Erik
> >>
> >>
> >> On 2018-10-10 06:14, Baesken, Matthias wrote:
> >>> Hello  , when  compiling   jdk/jdk   with  gcc 7.3.1    on linux x86_64 (or also
> >> on   linux ppc64)   I run into this build error :
> >>>
> >>>
> >>
> /open_jdk/jdk_just_clone/jdk/src/java.desktop/share/native/libfontmanag
> >> er/harfbuzz/hb-common.cc: In function 'void
> >> hb_variation_to_string(hb_variation_t*, char*, unsigned int)':
> >>
> /open_jdk/jdk_just_clone/jdk/src/java.desktop/share/native/libfontmanag
> >> er/harfbuzz/hb-common.cc:1066:27: error: '%g' directive output between
> 1
> >> and 18446744073709551615 bytes may cause result to exceed 'INT_MAX'
> [-
> >> Werror=format-truncation=]
> >>>      len += MAX (0, snprintf (s + len, ARRAY_LENGTH (s) - len, "%g",
> variation-
> >>> value));
> >>>
> >>
> ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >> ~~~~~~~~
> >>
> /open_jdk/jdk_just_clone/jdk/src/java.desktop/share/native/libfontmanag
> >> er/harfbuzz/hb-common.cc:1066:27: note: assuming directive output of
> >> 2147488582 bytes
> >>> cc1plus: all warnings being treated as errors
> >>>
> >>> (build is a product - build)
> >>>
> >>> Setting –disable-warnings-as-errors  works  as a workaround  ,  but of
> >> course this is not really   what we want to do .
> >>> Fixing  in the    harfbuzz   sources  in OpenJDk  might be also not so nice
> >> because it would clash with imports of new versions of harfbuzz .
> >>> Do you think we could disable  the specific warning for the library
> >> compilation ?
> >>> Any other great suggestions 😉 ?
> >>>
> >>>
> >>> Thanks, Matthias