[LLVMdev] Improving cast<> failure messages.

[Chris Lattner]

Depends a lot on the details, but this would be really really useful!

-Chris

On Jun 21, 2011, at 7:54 PM, Sean Hunt wrote:

> Would anyone object to an attempt to improve cast<> error messages by 
> outputting the expected type and the type received?
> 
> The interface I'm thinking of is to use ADL to do visitor-style lookup, 
> so we don't need to change every client. In particular, for clients in 
> clang, we can just create these functions implicitly from our 
> TableGen-generated files. I'm not sure about clients in LLVM since I 
> don't do much work there.
> 
> This would have to introduce a dependency in llvm/Support/Casting.h on 
> some library for string concatenation; preferably <string> but a 
> lower-level interface could be used it someone objects (or it could be 
> done manually, but that seems horrible).
> 
> An example of what this would be like is:
> 
> // Before cast<> in llvm/Support/Casting.h
> const char *DebugTypeName(void*) {
> }
> 
> // In the header for the type at some reasonable point before cast<> is
> // instatiated for that type
> const char *DebugTypeName(Foo*) {
>   return "Foo";
> }
> 
> The pointer is only for ADL purposes and will always be 0.
> 
> Sean
> _______________________________________________
> LLVM Developers mailing list
> LLVMdev at cs.uiuc.edu         http://llvm.cs.uiuc.edu
> http://lists.cs.uiuc.edu/mailman/listinfo/llvmdev