Hello,

I have a large project written in C99 handed to me that 32-bit builds in Windows with the mingw32 compiler that comes with msys2. I'm working on 64-bit Windows 10.

Need to solve some nasty problems and move the build to 64 bits using the mingw64 compiler that comes with msys2.

Want to use D to improve some parts of this monster. But am confused about ABI issues.

Which D compiler should be used to be ABI compatible with mingw32? And which to be ABI compatible with mingw64?

The most important is the D compiler that is ABI compatible with the 64-bit mingw compiler because that is where this project is going.

How can I use D in this situation, where I need it to work directly with C data? building DLLs is not going to work here for that reason.

On Wednesday, 20 May 2020 at 18:53:01 UTC, NonNull wrote:
> Which D compiler should be used to be ABI compatible with mingw32? And which to be ABI compatible with mingw64?
I am not expert here but doesnt all C compilers have the same ABI? If yes then compile your code in 32 bits for 32 bit C obj files. If you are on 64 bit OS then D compilers will produce 64 bit executables by default. To change that use https://dlang.org/dmd-linux.html#switch-m32

On Wednesday, 20 May 2020 at 18:53:01 UTC, NonNull wrote:
> Which D compiler should be used to be ABI compatible with mingw32? And which to be ABI compatible with mingw64?

The natural choice for coupling mingw[64]-gcc would be GDC. Especially wrt. ABI, gdc apparently doesn't have to do much by itself, in sharp contrast to LDC. No idea where gdc's MinGW[-w64] support is at though and whether you need more recent D features not available in gdc.

Wrt. LDC, I think the C ABI for the `-mtriple=x86_64-windows-gnu` target should be okay. IIRC, MinGW mostly adheres to Microsoft's official Win64 ABI and mostly just diverges wrt. `real` (80-bit x87 C `long double` vs. 64-bit double precision for MSVC), and that's covered by LDC IIRC. The C++ ABI (Itanium mangling, not the MSVC one) should be okay-ish; there might be differences wrt. what's considered a POD between MinGW and MSVC. Exception handling almost certainly doesn't work; TLS may likely not work either.

In general, druntime and Phobos don't fully support MinGW[-w64], but if you restrict yourself to -betterC code, that might not be a problem.

> How can I use D in this situation, where I need it to work directly with C data? building DLLs is not going to work here for that reason.

With -betterC, generating mixed DLLs shouldn't be any trouble at all.

On Wednesday, 20 May 2020 at 19:25:27 UTC, kinke wrote:
> On Wednesday, 20 May 2020 at 18:53:01 UTC, NonNull wrote:
>> Which D compiler should be used to be ABI compatible with mingw32? And which to be ABI compatible with mingw64?
>
> The natural choice for coupling mingw[64]-gcc would be GDC. Especially wrt. ABI, gdc apparently doesn't have to do much by itself, in sharp contrast to LDC. No idea where gdc's MinGW[-w64] support is at though and whether you need more recent D features not available in gdc.
> [...]

Thanks for the detailed information!

I see your point about gdc's ABI, but it seems gdc is not distributed for Windows at this juncture and I am looking for a simple way forward, so I will likely go with ldc2 with the option you suggested and see how it goes.

Thanks again!

On Wednesday, 20 May 2020 at 20:45:26 UTC, NonNull wrote:
> [...] so I will likely go with ldc2 with the option you suggested and see how it goes.
>
> Thanks again!

You're welcome. If you do come across an ABI issue, make sure to file an LDC issue. While I have no interest in MinGW, I want at least a working ABI.

On Wednesday, 20 May 2020 at 21:37:23 UTC, kinke wrote:
>
> You're welcome. If you do come across an ABI issue, make sure to file an LDC issue. While I have no interest in MinGW, I want at least a working ABI.

When you mention the ABI, is there something particular you have in mind or just in general?

On Wednesday, 20 May 2020 at 23:08:53 UTC, IGotD- wrote:
> On Wednesday, 20 May 2020 at 21:37:23 UTC, kinke wrote:
>>
>> You're welcome. If you do come across an ABI issue, make sure to file an LDC issue. While I have no interest in MinGW, I want at least a working ABI.
>
> When you mention the ABI, is there something particular you have in mind or just in general?

That's a question to TS, NonNull.

On Wednesday, 20 May 2020 at 23:10:12 UTC, IGotD- wrote:
> On Wednesday, 20 May 2020 at 23:08:53 UTC, IGotD- wrote:
>> On Wednesday, 20 May 2020 at 21:37:23 UTC, kinke wrote:
>>>
>>> You're welcome. If you do come across an ABI issue, make sure to file an LDC issue. While I have no interest in MinGW, I want at least a working ABI.
>>
>> When you mention the ABI, is there something particular you have in mind or just in general?
>
> That's a question to TS, NonNull.

General.

On Wednesday, 20 May 2020 at 23:08:53 UTC, IGotD- wrote:
> When you mention the ABI, is there something particular you have in mind or just in general?

The ABI for MinGW targets in general. - Judging by https://forum.dlang.org/post/anfwqjjsteeyelbdhdci@forum.dlang.org, you apparently use a very different definition of 'ABI'. See http://uclibc.org/docs/psABI-x86_64.pdf or https://docs.microsoft.com/en-us/cpp/build/x64-software-conventions?view=vs-2019 for what an ABI is.

I guess what you meant is the druntime API implicitly used by the compiler (mostly, the _d_* hooks like _d_assert, _d_newclass etc.). That's well-defined already, e.g., see https://github.com/ldc-developers/ldc/blob/master/gen/runtime.cpp.

On Wednesday, 20 May 2020 at 23:28:09 UTC, kinke wrote:
>
> The ABI for MinGW targets in general. - Judging by https://forum.dlang.org/post/anfwqjjsteeyelbdhdci@forum.dlang.org, you apparently use a very different definition of 'ABI'. See http://uclibc.org/docs/psABI-x86_64.pdf or https://docs.microsoft.com/en-us/cpp/build/x64-software-conventions?view=vs-2019 for what an ABI is.
>
> I guess what you meant is the druntime API implicitly used by the compiler (mostly, the _d_* hooks like _d_assert, _d_newclass etc.). That's well-defined already, e.g., see https://github.com/ldc-developers/ldc/blob/master/gen/runtime.cpp.

That's what I was thinking about, the ABI of x86-64 which originates from the ones that designed the ISA. The word ABI is used or misused in other areas as well, for example libc++abi which is a compatibility layer for libc++, that's why the word ABI turns up in a discussion about the druntime abstract interface.