gcc 7.3.1 build - warnings as errors in harfbuzz

[Erik Joelsson]

GCC (since some version older than we support now) ignores disabling of 
unknown warning labels. This is a feature we depend on for these 
constructs. Without that it wouldn't be possible to list all the labels 
like this.

(We used to check for this feature in GCC in configure and only use the 
warning disabling flags if GCC properly ignored unknowns, but since we 
require a newer version than that now, we no longer need to)

/Erik


On 2018-10-10 09:10, Baesken, Matthias wrote:
> 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