This allows one to place types like PointerIntPair and value types that wrap a
pointer into the pointer set.
I am making this change before I use this data structure in TransferNonSendable
and using ARC to validate that I haven't broken anything.
While doing bottom up dataflow, if we encounter an
unmatched retain instruction, that can pair with a 'KnownSafe'
already visited release instruction, we turn off KnownSafety if the two
RCIdentities mayAlias.
This is done in BottomUpRefCountState::checkAndResetKnownSafety.
In order to determine if a retain is umatched, we look at
IncToDecStateMap. If a retain was matched during bottom up dataflow, it
is always found in IncToDecStateMap with value of the matched release's
BottomUpRefCountState.
Similarly, during top down dataflow, if we encounter an unmatched
release instruction, that can pair with a 'KnownSafe' already
visited retain instruction, we turn off KnownSafety if the two RCIdentities
mayAlias.
This is done in TopDownRefCountState::checkAndResetKnownSafety.
In order to determine if a release is umatched, we look at
DecToIncStateMap. If a release was matched during top down dataflow, it
is always found in DecToIncStateMap with value of the matched retain's
TopDownRefCountState.
For ARCLoopOpts, during bottom up and top down traversal of a region with
a nested loop, we find if the retain/release in the loop summary was
matched or not by looking at the persistent RefCountInstToMatched map.
This map is populated when processing the nested loop region from the
IncToDecStateMap/DecToStateMap which gets thrown away after the loop
region is processed.
This fixes the bugs in both ARCSequenceOpts without loop
support and with loop support.
We've been running doxygen with the autobrief option for a couple of
years now. This makes the \brief markers into our comments
redundant. Since they are a visual distraction and we don't want to
encourage more \brief markers in new code either, this patch removes
them all.
Patch produced by
for i in $(git grep -l '\\brief'); do perl -pi -e 's/\\brief //g' $i & done
I see some small performance improvements on a few benchmarks, but they
are likely to be due to noise.
The compilation pipeline is very epilogue release friendly at the moment,i.e.
we do not move the epilogue release of a function till very late in the pipeline.
Therefore, this global data flow sort of an overkill. I am going to change
the pass pipeline next so that we can move epilogue releases freely and the data
flow will become useful.
I do not see compilation time increase.
rdar://26446587
This speeds and reduces memory consumption of test cases with large
CFGs. The specific test case that spawned this fix was a large function
with many dictionary assignments:
public func func_0(dictIn : [String : MyClass]) -> [String : MyClass] {
var dictOut : [String : MyClass] = [:]
dictOut["key5000"] = dictIn["key500"]
dictOut["key5010"] = dictIn["key501"]
dictOut["key5020"] = dictIn["key502"]
dictOut["key5030"] = dictIn["key503"]
dictOut["key5040"] = dictIn["key504"]
...
}
This continued for 10k - 20k values.
This commit reduces the compile time by 2.5x and reduces the amount of
memory allocated by ARC by 2.6x (the memory allocation number includes
memory that is subsequently freed).
rdar://24350646
Previously, we relied on a quirk in the ARC optimizer so that we only
need to visit terminators top down. This simplified the dataflow. Sadly,
try_apply changes this since it is a terminator that provides a call
with the value, causing this assumption to break program correctness.
Now during the bottom up traversal, while performing the dataflow for a
block B, we (after visiting all instructions), visit B's predecessors to
see if any of them have a terminator that is a use or decrement. We then
take the most conservative result among all of the terminators and
advance the sequence accordingly.
I do not think that we can have multiple such predecessors today since all
interesting terminators can not have any critical edges to successors. Thus if
our block is a successor of any such block, it can not have any other
predecessors. This is mainly for future proofing if we decide that this is able
to be done in the future.
rdar://23853221
SR-102
(libraries now)
It has been generally agreed that we need to do this reorg, and now
seems like the perfect time. Some major pass reorganization is in the
works.
This does not have to be the final word on the matter. The consensus
among those working on the code is that it's much better than what we
had and a better starting point for future bike shedding.
Note that the previous organization was designed to allow separate
analysis and optimization libraries. It turns out this is an
artificial distinction and not an important goal.
