Before this patch, every time you cloned a formula, the clone
visitor would recurse into the entire AST to increment the
reference count of all nodes. When running ltl2tgba_fm on
the formula generated by "LTLcounterLinear.pl 8", approx 27% of
the time was spent in the clone visitor.
After this patch, cloning a formula is just an increment of the
reference count of the top node. Children are decremented only
when the top node's ref count is decremented to zero. With this
change, clone() and destroy() become constant time, the
ltl2tgba_fm spend only 0.01% of the time cloning formulae.
* src/ltlast/automatop.cc (~automatop): Decrement children.
(instance): Decrement children if the instance already exists.
* src/ltlast/binop.cc, src/ltlast/multop.cc, src/ltlast/unop.cc:
Likewise.
* src/ltlvisit/clone.cc (clone): Simplify, now we only need to
call ref().
* src/ltlvisit/destroy.cc (destroy): Simplify, now we only need
to call unref().
(destroy_visitor): Remove, no longer needed.
two unabbreviate_logic definitions (const and non-const) into a
function that takes a const formula* and return a non-const
formula*. Since formula* is convertible to const formula*, and
the const version of the function just called the non-onst one, it
makes no sense to keep both. Also, it confused Swig.
* src/ltlvisit/nenoform.cc, src/ltlvisit/nenoform.hh: Likewise
for negative_normal_form.
* src/ltlvisit/tunabbrev.cc, src/ltlvisit/tunabbrev.hh: Likewise
for unabbreviate_ltl.
* src/ltlvisit/clone.cc, src/ltlvisit/clone.hh: Likewise for clone.
* src/ltlvisit/destroy.cc, src/ltlvisit/destroy.hh: Likewise
for destroy.
* src/ltlast/atomic_prop.hh: Declare instance_count().
* src/ltlast/binop.hh, src/ltlast/unop.hh, src/ltlast/multop.hh:
Likewise. Also, really inherit for ref_formula this time.
* src/ltlast/atomic_prop.cc, src/ltlast/binop.cc,
src/ltlast/unop.cc, src/ltlast/multop.cc: On destruction, suppress
the instance from the instance map. Implement instance_count().
* src/ltlast/formula.cc, src/ltlast/formula.hh,
src/ltlast/ref_formula.cc, src/ltlast/ref_formula.hh: Add virtual
destructors.
* src/ltlparse/ltlparse.yy: Recover from binary operators with
missing right hand operand (the point is just to destroy the
the left hand operand).
* src/ltltest/equals.cc, src/ltltest/readltl.cc,
src/ltltest/tostring.cc: Destroy used formulae. Make sure
instance_count()s are null are the end.
* src/ltltest/parseerr.test: Adjust expected result, now
that the parser lnows about missing right hand operands.
* src/ltlvisit/destroy.hh, src/ltlvisit/destroy.cc,
src/ltlvisit/postfix.hh, src/ltlvisit/postfix.cc: New files.
* src/ltlvisit/Makefile.am (libltlvisit_la_SOURCES): Add them.
* src/ltlvisit/lunabbrev.cc (Xor, Equiv): Clone formulae
occurring twice in the rewritten expression.
