RFR: 8288759: GCC 12 fails to compile signature.cpp due to -Wstringop-overread bug

[Kim Barrett]

On Sat, 25 Jun 2022 07:31:55 GMT, Kim Barrett <kbarrett at openjdk.org> wrote:

>> Trying to compile with GCC 12.1.1 (current Fedora Rawhide) yields this failure:
>> 
>> 
>> In file included from /home/test/shipilev-jdk/src/hotspot/share/utilities/globalDefinitions_gcc.hpp:35,
>>                  from /home/test/shipilev-jdk/src/hotspot/share/utilities/globalDefinitions.hpp:35,
>>                  from /home/test/shipilev-jdk/src/hotspot/share/memory/allocation.hpp:29,
>>                  from /home/test/shipilev-jdk/src/hotspot/share/classfile/classLoaderData.hpp:28,
>>                  from /home/test/shipilev-jdk/src/hotspot/share/precompiled/precompiled.hpp:34:
>> In function 'const void* memchr(const void*, int, size_t)',
>>     inlined from 'int SignatureStream::scan_type(BasicType)' at /home/test/shipilev-jdk/src/hotspot/share/runtime/signature.cpp:343:32,
>>     inlined from 'void SignatureStream::next()' at /home/test/shipilev-jdk/src/hotspot/share/runtime/signature.cpp:373:19,
>>     inlined from 'void SignatureIterator::do_parameters_on(T*) [with T = Fingerprinter]' at /home/test/shipilev-jdk/src/hotspot/share/runtime/signature.hpp:635:41,
>>     inlined from 'void SignatureIterator::do_parameters_on(T*) [with T = Fingerprinter]' at /home/test/shipilev-jdk/src/hotspot/share/runtime/signature.hpp:629:6,
>>     inlined from 'void Fingerprinter::compute_fingerprint_and_return_type(bool)' at /home/test/shipilev-jdk/src/hotspot/share/runtime/signature.cpp:169:19:
>
> src/hotspot/share/utilities/compilerWarnings_gcc.hpp line 60:
> 
>> 58: #if !defined(__clang_major__) && (__GNUC__ >= 8)
>> 59: #define PRAGMA_STRINGOP_TRUNCATION_IGNORED PRAGMA_DISABLE_GCC_WARNING("-Wstringop-truncation")
>> 60: #endif
> 
> Why was `PRAGMA_STRINGOP_TRUNCATION` moved?  Oh, I see, you are reordering based on version.  I'd rather all three of these `-Wstringop-xxx` were together, perhaps sorted alphabetically.  I don't see the use of a version ordering.  So my preference would be that this part of the change wasn't made.

But note this part of the change shouldn't be done at all, per my comments elsewhere.

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PR: https://git.openjdk.org/jdk19/pull/49