Mostly rewrite debug info generation in terms of llvm/Analysis/DebugInfo.h. Add getCompilationModule to Dsymbol and fix template compile unit decision code. Runtime compiles with -g again.

module bug43;

struct S
{
    ubyte[3] vals;
}

void func(ubyte[3] v)
{
}

void main()
{
    S s;
    func(s.vals);
}