Need help with Windows linkage ( DMD using ImportC)

[Gregor Mückl]

On Tuesday, 5 March 2024 at 00:20:36 UTC, Carl Sturtivant wrote:
> On Monday, 4 March 2024 at 21:21:20 UTC, Carl Sturtivant wrote:
>> ```
>> blah.obj: error LNK2019: unresolved external symbol _mul128 
>> referenced in function MultiplyExtract128
>> blah.obj: error LNK2019: unresolved external symbol 
>> __shiftright128 referenced in function MultiplyExtract128
>> blah.obj: error LNK2019: unresolved external symbol _umul128 
>> referenced in function UnsignedMultiplyExtract128
>> blah.obj: error LNK2019: unresolved external symbol __stosb 
>> referenced in function RtlSecureZeroMemory
>> blah.obj: error LNK2019: unresolved external symbol 
>> __readgsqword referenced in function NtCurrentTeb
>> blah.obj: error LNK2019: unresolved external symbol 
>> __imp_MapViewOfFileNuma2 referenced in function MapViewOfFile2
>> blah.obj: error LNK2019: unresolved external symbol 
>> __imp_CharUpperW referenced in function ua_CharUpperW
>> ```
>
> I forced linkage of these unused symbols as follows, but it 
> would be nice to have a clean way to proceed.
> ```D
> extern(C) {
>     int _InterlockedExchangeAdd(int* Addend, int Value) { 
> return 0; };
>     long _InterlockedExchangeAdd64(long* Addend, long Value) { 
> return 0; }
>     void _mul128() {};
>     void __shiftright128() {};
>     void _umul128() {};
>     void __stosb() {};
>     void __readgsqword() {};
>     void __imp_MapViewOfFileNuma2() {};
>     void __imp_CharUpperW() {};
> }
> ```
> I got the D signatures of the first two so as to generate the 
> correct linkage by using ImportC to translate the inclusion of 
> `Windows.h` into a .di file, and searching.

This looks like a combination of two issues:

1. Missing import libraries for Win32 API functions. Anything 
starting with `__imp_` is a symbol that should be provided by a 
DLL import library. MapViewOfFileNuma2 for example is provided  
by onecore.lib in the Windows SDK, according to Microsoft 
documentation.

2. C code referring to MSVC-specific compiler intrinsics. At 
least InterlockedExchangeAdd, InterlockedExchangeAdd64 and _stosb 
are such intrinsics. This is harder to resolve. There are two 
ways forward here: either implement a shim function that 
replicates the intrinsic's functionality if possible or add 
support for these intrinsics to DMD.