On Sep 12, 2007, at 11:14 AM, Gordon Henriksen wrote:
> Hm. Are you sure this is wise? I realize my patch didn't provide
> root initialization, but I have that fixed locally. Without
> liveness analysis, leaving stack roots uninitialized seems unwise,
> since gc points are not entirely predictable from the IR.
I think it is fine. trivially, any front-end that produced a call to
the gcroot intrinsic could emit that intrinsic and a store of null,
so there is no power lost here.
The reason it is useful is for things like this (C syntax):
void foo(object *P) {
gcroot(&P, 0);
... use P ...
}
when converted to LLVM, this turns into the equivalent of:
void foo(object *P) {
P_addr = alloca object*
store P -> P_addr
gcroot(P_addr, 0);
... use *P_addr...
}
With the null'ing property of gcroot, it would clobber the live in
value.
-Chris
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