Re: Pros and cons of high-level intermediate languages

nfsun!gchamber@uunet.UU.NET (Glenn Chambers) writes:
>[one could force references to GC-able pointers with]


> extern volatile void * __gc_sink;
> #define _GC_USE(x) __gc_sink = (void *) (x)


>[and in an assembler post-pass remove the dead code thereby generated]
>The way that we (Hans Boehm and I) see this going wrong is if "x" is
>reconstituted (say, from other induction variables) at the _GC_USE.


I think the following code might be safer plus avoid some of the register
pressure. A post-pass over the assembly language is still needed to
remove the unnecessary fetches (or other implementation-defined access to
volatiles). Of course, if the translator to C declares register x, then
this doesn't work.


      #define _GC_USE(x) *(volatile void *)&x;


--
Norman Diamond diamond@jit081.enet.dec.com
--

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