llvm dev - Apr 2013 - [LLVMdev] Q: clang, obj-c: Hashing selectors to SEL's.

I'm trying to understand the method dispatch in objc_MsgSend.

At some point during compilation, ascii selectors are hashed
into integer SEL's. Is this hash somehow guaranteed to be unique?
If so, how? If not, how are collisions handled? Is this hashing
done during the link phase?

Any insights/pointers to the code/documentation related to this
hashing would be greatly appreciated.

Thanks,

Charlie

This is a question specific to Apple's Objective-C runtime and would be more
appropriately addressed to Apple's Objective-C mailing list.

David

On 13 Apr 2013, at 21:10, Charlie Burns <crb at sonic.net> wrote:
> 
> I'm trying to understand the method dispatch in objc_MsgSend.
> 
> At some point during compilation, ascii selectors are hashed
> into integer SEL's. Is this hash somehow guaranteed to be unique?
> If so, how? If not, how are collisions handled? Is this hashing
> done during the link phase?
> 
> Any insights/pointers to the code/documentation related to this
> hashing would be greatly appreciated.
> 
> Thanks,
> 
> Charlie
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