Pack MDEI struct to fix issue #4407

[tf2spi]

MINIDUMP_EXCEPTION_INFORMATION is expected to be packed (which is, of course, not documented by MSDN) so this packs it so that it can be used in MinidumpWriteDump.

[tf2spi]

Additional Note: I haven't looked at the AARCH64 headers for Windows yet so I don't know if that specific architecture also expects the struct to be packed or not.

[gingerBill]

So it's technically not #packed but you need #max_field_align(4).

[gingerBill]

struct #max_field_align(4)

[tf2spi]

Oh, cool! I didn't know that was a directive!

This seems good but I don't know if I'm applying the directive right? I'm getting alignment errors after using it.

Below is the disassembly from Visual Studio

        mdei: MINIDUMP_EXCEPTION_INFORMATION
00007FF74395AD64  movaps      xmmword ptr [rsp+1E0h],xmm0  
        mdei.ThreadId = GetCurrentThreadId()
00007FF74395AD6C  call        GetCurrentThreadId (07FF74395B412h)  
00007FF74395AD71  mov         ecx,eax  
00007FF74395AD73  mov         rax,qword ptr [rsp+0B8h]  
00007FF74395AD7B  mov         dword ptr [rsp+1E0h],ecx  
        mdei.ExceptionPointers = pException    // pass in 'nil' would make MiniDumpWriteDump() return TRUE
00007FF74395AD82  mov         qword ptr [rsp+1E8h],rax  
        mdei.ClientPointers = FALSE
00007FF74395AD8A  mov         dword ptr [rsp+1F0h],0  

Below is the LLVM IR

  %48 = getelementptr inbounds %sys_windows.MINIDUMP_EXCEPTION_INFORMATION, ptr %mdei, i32 0, i32 0, !dbg !341
  %49 = call x86_stdcallcc i32 @GetCurrentThreadId(), !dbg !341
  store i32 %49, ptr %48, align 4, !dbg !341
  %50 = getelementptr inbounds %sys_windows.MINIDUMP_EXCEPTION_INFORMATION, ptr %mdei, i32 0, i32 1, !dbg !342
  store ptr %0, ptr %50, align 8, !dbg !342
  %51 = getelementptr inbounds %sys_windows.MINIDUMP_EXCEPTION_INFORMATION, ptr %mdei, i32 0, i32 2, !dbg !343
  store i32 0, ptr %51, align 4, !dbg !343

This is the diff

diff --git a/core/sys/windows/dbghelp.odin b/core/sys/windows/dbghelp.odin
index 4bbad258d..e32b4c874 100644
--- a/core/sys/windows/dbghelp.odin
+++ b/core/sys/windows/dbghelp.odin
@@ -15,7 +15,7 @@ MINIDUMP_DIRECTORY :: struct {
        Location:   MINIDUMP_LOCATION_DESCRIPTOR,
 }

-MINIDUMP_EXCEPTION_INFORMATION :: struct #packed {
+MINIDUMP_EXCEPTION_INFORMATION :: struct #max_field_align(4) {
        ThreadId:          DWORD,
        ExceptionPointers: ^EXCEPTION_POINTERS,
        ClientPointers:    BOOL,

And here's the version to show I did update the compiler.

..\odin.exe version dev-2024-11:c4b273958

[tf2spi]

Other weirdness is also happening. The debug info says that it's packed.

and Odin code is crashing when using fmt.printf on the mdei

fmt.printf crashing is at least odd and I'll investigate this further

[tf2spi]

Now relies on #4611