Bug #79356 [Opn]: FFI:structure/union alignment [ext/ffi/tests/022.phpt] failure

Edit report at https://bugs.php.net/bug.php?id=79356&edit=1 ID: 79356 Updated by: nikic@php.net Reported by: vibhutisawant18 at gmail dot com Summary: FFI:structure/union alignment [ext/ffi/tests/022.phpt] failure Status: Open Type: Bug Package: Testing related Operating System: Ubuntu 16.04 PHP Version: master-Git-2020-03-09 (Git) -Assigned To: +Assigned To: dmitry Block user comment: N Private report: N New Comment: @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? Previous Comments: ------------------------------------------------------------------------ [2020-03-09 10:21:18] nikic@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. ------------------------------------------------------------------------ [2020-03-09 10:09:21] nikic@php.net Something odd is going on here. The test passes for me on 7.4, but fails on master. Adding a bit more debug output I get: FAIL: sizeof(struct {char a; uint32_t b __attribute__((aligned));}) Expected: 32 Actual: 64 FAIL: alignof(struct {char a; uint32_t b __attribute__((aligned));}) Expected: 16 Actual: 32 So I'm seeing a higher size/alignment for some reason. ------------------------------------------------------------------------ [2020-03-09 09:50:26] vibhutisawant18 at gmail dot com ext/ffi/tests/022.phpt passed on x86-64.PFB the test log. root@a11efdc33877:~/php/php-src# sapi/cli/php -f "ext/ffi/tests/022.phpt" --TEST-- FFI 022: structure/union alignment --SKIPIF-- --INI-- ffi.enable=1 --FILE-- ok --EXPECT-- ok root@a11efdc33877:~/php/php-src# arch x86_64 root@a11efdc33877:~/php/php-src# ------------------------------------------------------------------------ [2020-03-09 08:17:12] nikic@php.net This test also fails for me on a x86-64, so not big endian specific. ------------------------------------------------------------------------ [2020-03-09 05:53:16] vibhutisawant18 at gmail dot com The following patch has been added/updated: Patch Name: FFI_structure_union_alignment_s390x Revision: 1583733196 URL: https://bugs.php.net/patch-display.php?bug=79356&patch=FFI_structure_union_alignment_s390x&revision=1583733196 ------------------------------------------------------------------------ The remainder of the comments for this report are too long. To view the rest of the comments, please view the bug report online at https://bugs.php.net/bug.php?id=79356 -- Edit this bug report at https://bugs.php.net/bug.php?id=79356&edit=1