On Jul 16, 2012, at 3:58 PM, Duncan Sands wrote: > Hi Tristan, > >>> indeed, for two years already. Is there any reason not to do this for all >>> functions, rather than just limiting it to builtins? >> >> I don't understand what do you mean. We need to do this implicit conversion >> for builtins because they are known by the compiler. Which other functions >> (that aren't builtins) are you referring to ? > > all of them! First off, the LLVM optimizers do a better job if an argument > of a > user defined function that is really a pointer is declared as such, rather > than > declared as an integer then cast to a pointer before being used. I don't know > if the GCC optimizers are sensitive to this too. Also, the LLVM optimizers > recognize some standard library functions that the gcc optimizers do not, but > fail to recognize them when called from Ada because they have the wrong > prototype: an integer rather than a pointer argument. Finally I would argue > that as System.Address is really a pointer, playing pretty much exactly the > same role as void* in C, it is more philosophically correct to express it as a > void*. That said, it should probably just be declared as a pointer in the > System package rather than doing all this mucking around in the gcc interface.
Ah, what you want is the use of 'void *' for System.Address. We didn't choose that because the semantic of System.Address (which includes arithmetic on the whole address space) doesn't match the void * one. But, you can try to implement this scheme by modifying the runtime. I don't know if this is a small work or not. Tristan.
