On 02/17/17 14:15, Stephan Bergmann wrote: > On 02/17/2017 11:48 AM, Alex Peshkoff wrote: >> On 02/16/17 15:52, Stephan Bergmann wrote: >>> Forgive me if this has already been discussed or even fixed in later >>> versions: At least the Firebird 3.0 we build as part of LibreOffice >>> defines global operator new replacement functions in >>> src/common/classes/alloc.h (forwarding to MemoryPool) that do not in >>> general fulfil the alignment requirements for such functions. >>> >>> Came across this when Firebird compiled with a recent trunk Clang (with >>> -O, and DEBUG_GDS_ALLOC being undefined) on x86_64-unknown-linux-gnu >>> causes SEGV from misaligned MOVAPS instructions. >>> >> Yes - allocated memory is aligned at 8 bytes boundary now. >> I've tried to set alignment to 16 but looks like that's far not 5 lines >> patch - sometimes we were choosing between 4/8 bytes alignment, but last >> years only 8 bytes alignment was used. >> May be finding specific compiler flag to avoid this instruction is >> simpler choice for today? > (The way I work around this for now in LibreOffice is by always defining > DEBUG_GDS_ALLOC when building with Clang on Linux X86-64, > <https://cgit.freedesktop.org/libreoffice/core/commit/?id=8ea07101c1613d213fd7cea17f094a947b14cd00> > "external/firebird: Work around operator new alignment violations". > Since LibreOffice builds intended for widespread distribution are on > Linux usually done with GCC not Clang, this shouldn't have a performance > impact.)
Afraid that this work around is not too stable (not to say more). Certainly that macro does change details of memory allocation and may provide 16-bit alignment in some particular case but be sure it's not more than side effect and does not gurantee such alignment. ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, SlashDot.org! http://sdm.link/slashdot Firebird-Devel mailing list, web interface at https://lists.sourceforge.net/lists/listinfo/firebird-devel
