Dynamic by default on Windows

We don't currently support dynamic-by-default on Windows. The issue is that, when building a dynamically linked library on Windows, there is no equivalent of elf's RPATH to tell the executable where its libraries are. This means that, unless the libraries have been installed to a global directory such as c:/windows/system, ghc --make foo would have to copy all the DLLs used to the current directory.

Assemblies

Windows does actually have a similar concept to RPATHs: assemblies. These do allow us to give the location of DLLs that we use, but only as relative paths, and using at most 2 ../s. It's therefore not possible to use assemblies to say that we use c:/ghc/base/base.dll. This therefore doesn't generally allow us to solve the problem.

C stub

A simple option would be for ghc --make foo to link all of foo's code into foo.exe.dll, and then make foo.exe by generating and compiling a C stub that does

AddDllDirectory("...");
AddDllDirectory("...");
LoadLibrary("foo.exe.dll);

However, this is a little klunky, as there is now an extra file needed for every executable. It would also likely cause problems for build systems.

Loading DLL resource from memory

An improvement