[PATCH 0/1] MR1114: ntdll/tests: Force alignment of output structures.

[eric pouech (＠epo)]

Some Windows version expect output to be aligned on 4 bytes.

Notes (from i386 and x86_64 tests):
- MSVC and Mingw/gcc don't layout the two variables (sdki, sdki_ex)
  the same way.
- MSVC aligns each variable on 4-byte boundary,
- MingW/GCC stores them in a 8-byte chunk, but starting from the
  end of the buffer: hence none of them is on a 4-byte boundary.

So, fixing the alignment of variables is not sufficient to
workaround the compilers' discrepancy on all source code.

I didn't find a generic way to align on 4 bytes structures of size
smaller than 4 bytes (apart from adding the DECLSPEC_ALIGN to
each of the offending structures, likely not that many though).
Ideas welcomed.

Wine-Bugs: https://bugs.winehq.org/show_bug.cgi?id=53684

Signed-off-by: Eric Pouech <eric.pouech(a)gmail.com>

-- 
https://gitlab.winehq.org/wine/wine/-/merge_requests/1114

[PATCH 1/1] ntdll/tests: Force alignment of output structures.

[Eric Pouech]

From: Eric Pouech <eric.pouech(a)gmail.com>

Some Windows version expect output to be aligned on 4 bytes.

Notes (from i386 and x86_64 tests):
- MSVC and Mingw/gcc don't layout the two variables (sdki, sdki_ex)
  the same way.
- MSVC aligns each variable on 4-byte boundary,
- MingW/GCC stores them in a 8-byte chunk, but starting from the
  end of the buffer: hence none of them is on a 4-byte boundary.

So, fixing the alignment of variables is not sufficient to
workaround the compilers' discrepancy on all source code.

I didn't find a generic way to align on 4 bytes structures of size
smaller than 4 bytes (apart from adding the DECLSPEC_ALIGN to
each of the offending structures, likely not that many though).
Ideas welcomed.

Wine-Bugs: https://bugs.winehq.org/show_bug.cgi?id=53684

Signed-off-by: Eric Pouech <eric.pouech(a)gmail.com>
---
 dlls/ntdll/tests/info.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/dlls/ntdll/tests/info.c b/dlls/ntdll/tests/info.c
index 0af4259b85d..bef982b20b0 100644
--- a/dlls/ntdll/tests/info.c
+++ b/dlls/ntdll/tests/info.c
@@ -1066,8 +1066,9 @@ static void test_query_kerndebug(void)
 {
     NTSTATUS status;
     ULONG ReturnLength;
-    SYSTEM_KERNEL_DEBUGGER_INFORMATION_EX skdi_ex;
-    SYSTEM_KERNEL_DEBUGGER_INFORMATION skdi;
+    /* some Windows version expect alignment */
+    SYSTEM_KERNEL_DEBUGGER_INFORMATION_EX DECLSPEC_ALIGN(4) skdi_ex;
+    SYSTEM_KERNEL_DEBUGGER_INFORMATION DECLSPEC_ALIGN(4) skdi;
 
     status = pNtQuerySystemInformation(SystemKernelDebuggerInformation, &skdi, 0, &ReturnLength);
     ok( status == STATUS_INFO_LENGTH_MISMATCH, "Expected STATUS_INFO_LENGTH_MISMATCH, got %08lx\n", status);
-- 
GitLab

https://gitlab.winehq.org/wine/wine/-/merge_requests/1114

[PATCH 1/1] ntdll/tests: Force alignment of output structures.

[Zebediah Figura]

On 10/20/22 03:54, Eric Pouech wrote:
> From: Eric Pouech <eric.pouech(a)gmail.com>
>
> Some Windows version expect output to be aligned on 4 bytes.
>
> Notes (from i386 and x86_64 tests):
> - MSVC and Mingw/gcc don't layout the two variables (sdki, sdki_ex)
>    the same way.
> - MSVC aligns each variable on 4-byte boundary,
> - MingW/GCC stores them in a 8-byte chunk, but starting from the
>    end of the buffer: hence none of them is on a 4-byte boundary.
>
> So, fixing the alignment of variables is not sufficient to
> workaround the compilers' discrepancy on all source code.
>
> I didn't find a generic way to align on 4 bytes structures of size
> smaller than 4 bytes (apart from adding the DECLSPEC_ALIGN to
> each of the offending structures, likely not that many though).
> Ideas welcomed.

Should we put those structs in pshpack4/poppack in the header? (They 
aren't defined anywhere publicly on Windows, so we can't compare there.)