Edit report at https://bugs.php.net/bug.php?id=79356&edit=1
ID: 79356
Updated by: dmi...@php.net
Reported by: vibhutisawant18 at gmail dot com
Summary: FFI:structure/union alignment
[ext/ffi/tests/022.phpt] failure
-Status: Assigned
+Status: Closed
Type: Bug
Package: Testing related
Operating System: Ubuntu 16.04
PHP Version: master-Git-2020-03-09 (Git)
Assigned To: dmitry
Block user comment: N
Private report: N
New Comment:
ext/ffi/tests/022.phpt failure is fixed by exporting FFI::__BIGGEST_ALIGNMENT__
constant.
Anyway, __attribute__((aligned)) without argument may cause invalid alignment
assumption, if library and PHP were compiled with different options. The same
situation with C.
Previous Comments:
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[2020-03-11 12:34:34] dmi...@php.net
@nikic: I don't know, but in case GCC supports this, I would prefer to support
this as well.
The proposed fix https://github.com/php/php-src/pull/5256
------------------------------------------------------------------------
[2020-03-11 09:11:56] ni...@php.net
@dmitry: Do you know of some particular case where this is being used?
------------------------------------------------------------------------
[2020-03-11 09:07:00] dmi...@php.net
I'm not sure, if we should remove support for __attribute__((aligned)) without
specified alignment completely. Probably, we should export
__BIGGEST_ALIGNMENT__ constant and may be add a warning about dependency.
------------------------------------------------------------------------
[2020-03-09 10:24:04] ni...@php.net
@dmitry: I would suggest that we remove support for __attribute__((aligned))
without specified alignment, because it is not interoperable. If PHP was
combined with a different target architecture than the library we're linking
against, the alignment will be incorrect. We should force an explicit
specification of the alignment instead. What do you think?
------------------------------------------------------------------------
[2020-03-09 10:21:18] ni...@php.net
Okay, I see now. __attribute__((aligned)) is the same as
__attribute__((__BIGGEST_ALIGNMENT__)). I happened to use an -march=sandybridge
build, where __BIGGEST_ALIGNMENT__ is 32.
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