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Subject: Re: clang 20.1.8+21.1.1: __stdcall__ warning only from Cygwin version
To: cygwin@cygwin.com
References: <5c3c354b-8662-c961-9e13-bdfd4b6a9a75@t-online.de>
 <82307f10-1fb1-9f84-1ecb-8081bf224d29@jdrake.com>
Message-ID: <e95644c4-0962-c0fa-6601-5ed6ddd537c8@t-online.de>
Date: Tue, 16 Sep 2025 13:09:42 +0200
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From: Christian Franke via Cygwin <cygwin@cygwin.com>
Reply-To: cygwin@cygwin.com
Cc: Christian Franke <Christian.Franke@t-online.de>
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Jeremy Drake via Cygwin wrote:
> On Fri, 12 Sep 2025, Christian Franke via Cygwin wrote:
>
>> Testcase:
>>
>> $ cat winapi.c
>> #include <windows.h>
>> int WINAPI SomeDllFunction(int, int, int, int, int);
>>
>> int call_it()
>> {
>>     return SomeDllFunction(1, 2, 3, 4, 5);
>> }
>>
>> $ clang -S winapi.c  # with 20.1.8 and 21.1.1
>> winapi.c:2:5: warning: '__stdcall__' calling convention is not supported
>> for this target
>>         [-Wignored-attributes]
>>       2 | int WINAPI SomeDllFunction(int, int, int, int, int);
>>         |     ^
>> /usr/include/w32api/minwindef.h:98:16: note: expanded from macro 'WINAPI'
>>      98 | #define WINAPI __stdcall
>>         |                ^
>> <built-in>:400:34: note: expanded from macro '__stdcall'
>>     400 | #define __stdcall __attribute__((__stdcall__))
>>         |                                  ^
>> ...
> This should be fixed in 21.1.1-2, just uploaded.  Thanks for the report.

Now no warnings occur for ABI attributes stdcall, cdecl, ms_abi and 
sysv_abi. Only the latter results in different function call code (6 
instead of 4 parameters in registers, additional push/pop if xmm 
registers). This is consistent with gcc.

clang and x86_64-w64-mingw32-clang generate identical assembly files.

-- 
Thanks,
Christian


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