🚀 go-pugleaf

In article <759@vaxb.calgary.UUCP> radford@calgary.UUCP writes:
>Shouldn't a compiler smart enough to allocate variables to registers be
>smart enough to see that a local variable is never the operand of the
>& (address-of) operator, and thus cannot be referenced by a pointer?
>Both of these tasks seem to require that the procedure be completely
>scanned before code generation.

Unfortunately, you don't have to take the address of a given variable
to use it, you merely have to take the address of a variable near it
and add an offset to it.  The way C is defined, this is quite legal.

For example, suppose I have a function f, declared as follows:
	f(p)
		struct { int a, b, c; } *p;
	{
	...
	}
And I call it as follows:
	b()
	{
		int a, b, c;

		f( &a );
	}
According to our venerable friends kerningham&ritchie, this is legal;
it is also used to some great extent in the older (v6 & v7) unix kernels.
>    Radford Neal
>    The University of Calgary


-- 
 Marc Mengel
 ...!ihnp4!cuuxb!mwm