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Re: needless deep recursion in gt-c-decl.h
Geoff Keating wrote:
This won't avoid the LABEL_REF. It will be encountered the first time
it's used in RTL, which will still be much earlier than the position
of the label.
Same point: Do we really need to follow LABEL_REFs? Aren't their
targets guaranteed to be referenced by something else?
General point: We're acting as if we're implementing a general-purpose
garbage collector that needs to work without any knowledge of the
semantics of its objects beyond being able to chase pointers. However,
we don't need a general gc - we just need something that works for gcc.
And gcc doesn't willy-nilly allocate chunks of rtl and stash them in
random places. We know how gcc allocates and uses rtl. Thus we don't
need to chase every cross-reference and back-pointer - they are
redundant, if the compiler isn't broken. (Of course having self-checks
in the compiler is good. But that's a separate issue.)
(Of course if we were implementing a general-purpose garbage collector
we should not use recursion to follow pointers!)
--
--Per Bothner
per@bothner.com http://www.bothner.com/per/