Req #78270 [Opn->Fbk]: Usage of __vectorcall convention with FFI

Edit report at https://bugs.php.net/bug.php?id=78270&edit=1 ID: 78270 Updated by: ab@php.net Reported by: lisachenko dot it at gmail dot com Summary: Usage of __vectorcall convention with FFI -Status: Open +Status: Feedback Type: Feature/Change Request Package: Unknown/Other Function Operating System: Windows x64 PHP Version: 7.4.0alpha2 Block user comment: N Private report: N New Comment: Thanks for the report. The vectorcall calling convention for 64-bit is the analogue of fastcall on 32-bit. 64-bit supports a very few calling conventions, vectorcall is the most advanced one compared to both default 64-bit and to fastcall. The latest libffi has been released quite a long ago, it might make sense to check whether the latest dev supports vectorcall. It would be also the preferable way, as vectorcall is per se a far better option than the default x64 calling convention. Performance improvements was the reason switching to it back then, and removing it just out of hand without a good QA would be IMO a no go. On a case-by-case base, one could check where such a switch wouldn't impact, but for sure not just a blanket removal. Also not sure the note about x32, did you mean x86? Also, could you please put a piece of code one could start with? Perhaps a list of functions where the issue was met. Thanks. Previous Comments: ------------------------------------------------------------------------ [2019-07-10 13:37:41] lisachenko dot it at gmail dot com Description: ------------ I'm trying to import AST internal PHP functions with FFI, but for Windows platform this brings a lot of pain, because __vectorcall convention is used. It was introduced in https://github.com/php/php-src/commit/3b6cd5fe4ce81d3d219887339f3915140214708c Unfortunately, libffi doesn't support vectorcall convention, thus symbol could not be imported properly with FFI. Is it possible to remove such specific calling convention, used for ZEND_FASTCALL macros for 7.4.0 and just switch to traditional one: __fastcall for x32. For x64 platform Expected result: ---------------- All exported PHP functions don't use vectorcall convention anymore. Actual result: -------------- Some PHP functions are exported as vectorcall-functions (have double @@ at the end with number of additional bytes), for example, "zend_ast_evaluate@@24" and could not be imported with FFI under Windows platform. ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=78270&edit=1