dmd: Move all public C++ functions into a dmd namespace

[ibuclaw]

As discussed @kinke / @RazvanN7.

extern(C++) can/should be move to separate PR - I've just bundled it all in here, as it was simpler to fix them up so they didn't appear in the regexp I was using to match functions as I was going through them.

---

Update: now all extern(C++) top-level functions are in one (boilerplate) leaf module.

[dlang-bot]

Thanks for your pull request, @ibuclaw!

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[ibuclaw]

Might have to park this for a while, the ability to import symbols in C++ "namespaces" wasn't added until 2.087.

https://issues.dlang.org/show_bug.cgi?id=19893

Workaround is to (1) remove all selective imports, and (2) add these in the same module as the definition.

static if (__VERSION__ < 2087)
{
    public Expression ctfeInterpret(Expression e)
    {
        return __traits(getMember, dmd.dinterpret.dmd, "ctfeInterpret")(e);
    }
}

[ibuclaw]

Might have to park this for a while, the ability to import symbols in C++ "namespaces" wasn't added until 2.087.

https://issues.dlang.org/show_bug.cgi?id=19893

Workaround is to (1) remove all selective imports, and (2) add these in the same module as the definition.

static if (__VERSION__ < 2087)
{
    public Expression ctfeInterpret(Expression e)
    {
        return __traits(getMember, dmd.dinterpret.dmd, "ctfeInterpret")(e);
    }
}

Sitting on this, I think alternatively this could be turned on its head.

1. Remove extern(C++) from all these functions.

// dmd.mtype
extern (D) Type mutableOf(Type t) { ... }

2. Create a new leaf module for exposing D code to the C++ API.

module dmd.cxxfrontend;
static import dmd.mtype;
extern(C++, "dmd"):
Type mutableOf(Type t)
{
    return dmd.mtype.mutableOf(t);
}

@kinke any better ideas?

[ibuclaw]

Now all C++ definitions have been put in a leaf module - not compiled into DMD, but for the C++ FE unittester only - there's nothing blocking this. We can continue having 2.079 as our baseline version, this module is only for GDC and LDC anyway.

[ibuclaw]

@kinke I'm yet to give this a test against gdc, but please do have a glance at it regardless. I've put a few functions in version(IN_LLVM) because gdc doesn't call them from the C++ side.

[ibuclaw]

One extern(C++) definition escaped my regex - #16182 - with that additional change, everything links. For my own sanity, have tested bootstrapping from gdc-9, gdc-11, and gdc-13.

[RazvanN7]

Looks good to me. Mind the conflict and we are good to go.

@kinke any objections?

[kinke]

No objections, should be good. I probably won't be able to check this before merging v2.108 into LDC, so might follow up then.