Some signatures (involving out parameters) seem to be wrong

[TChatzigiannakis]

I think some of the signatures generated by the script are wrong. I will explain why I think this is the case, but I'd like someone else to validate it as well, as I haven't gotten around to testing it yet.

Consider the example of LLVMDiagnosticHandler. On the C side, it is defined as:

typedef void (*LLVMDiagnosticHandler)(LLVMDiagnosticInfoRef, void *);

Where LLVMDiagnosticInfoRef is:

typedef struct LLVMOpaqueDiagnosticInfo* LLVMDiagnosticInfoRef

Because of this, I'm guessing LLVMDiagnosticHandler is seen by the script as:

typedef void (*LLVMDiagnosticHandler)(LLVMOpaqueDiagnosticInfo*, void *);

And the script emits the following delegate type:

[UnmanagedFunctionPointer(CallingConvention.Cdecl)]
public delegate void LLVMDiagnosticHandler(out LLVMOpaqueDiagnosticInfo @param0, IntPtr @param1);

On the C++ side, setting the diagnostic handler simply saves the passed arguments and, at a later point, another function calls the function pointer and passes a const DiagnosticInfo& to it. I think this means that the C++ side expects that first parameter to be an input parameter passed by reference, while the C# side assumes it is an output parameter.

If this is the case, an LLVMSharp user might not be able to create a useful handler, because the C# compiler will force any handler to overwrite the out parameter explicitly (or the C# compiler will insert an implicit overwrite). This means that anything passed to the handler from the C++ side will be lost (and the handler could even corrupt the state of the C++ side). Changing the script to generate ref instead of out should fix that.

I don't know how many other types may have this issue -- this simply happened to be the first one I attempted to work on.

[mjsabby]

Fixed in eeb7e37