NOTE: debug_value [moved] appearing in the source code implies a _move was
used. So this will not effect current stable swift code.
This is just a first version of this that I am using to commit/bring up tests
for IRGen supporting a full dataflow version of this patch.
Big picture is that there is a bunch of work that is done in the LLVM level in
the coroutine splitter to work around communicating live variables in the
various coroutine func-lets. This logic is all done with debug.declare and we
would need to update that logic in the coroutine splitter to handle
debug.addr. Rather than do this, after some conversation, AdrianP and I realized
that we could get the same effect of a debug.declare by just redeclaring the
current live set of debug_value after each possible coroutine funclet start. To
do this in full generality, we need a full dataflow but just to bring this up we
initially perform a dominance propagation algorithm of the following sort:
1. We walk the CFG along successors. By doing this we guarantee that we visit
blocks after their dominators.
2. When we visit a block, we walk the block from start->end. During this walk:
a. We grab a new block state from the centralized block->blockState map. This
state is a [SILDebugVariable : DebugValueInst].
b. If we see a debug_value, we map blockState[debug_value.getDbgVar()] =
debug_value. This ensures that when we get to the bottom of the block, we
have pairs of SILDebugVariable + last debug_value on it.
c. If we see any coroutine funclet boundaries, we clone the current tracked
set of our block state and then walk up the dom tree dumping in each block
any debug_value with a SILDebugVariable that we have not already
dumped. This is maintained by using a visited set of SILDebugVariable for
each funclet boundary.
The end result is that at the beginning of each funclet we will basically
declare the debug info for an addr.
This is insufficient of course for moves that are in conditional control flow,
e.x.:
```
let x = Klass()
if boolValue {
await asyncCall()
let _ = _move(x)
}
```
but this at least lets me begin to write tests for this in lldb using straight
line code and work out the rest of the issues in CodeGen using those tests.
Handle recursive non-escaping local functions.
Previously, it was thought that recursion would force a closure to be
escaping. This is not necessarilly true.
Update AccessEnforcementSelection to conservatively handle closure cycles.
Fixes rdar://88726092 (Compiler hangs when building)
We had two copies of this code that had drifted apart. Bring them back
together so there is just one place where we compute the type of a
reabstraction thunk.
The reason why I am doing this is that right now SelectionDAG seems to sink
certain llvm.dbg.addr to the end of block. By breaking the block, we ensure that
we initialize the debug value of values early enough. NOTE: We are relying on
code at -Onone not eliminating control flow which it does not today.
A few additional notes:
1. I also fixed a small issue where I was not setting the proper debug scope for
reinit debug_values. This came up when I was writing test cases for this commit.
So I just fixed it at the same time.
2. Since I am splitting blocks and I don't want to invalidate dominators/etc at
this point in the pipeline, I took advantage of the APIs ability to update
dominators/loopinfo at the same time.
3. I also expanded the tests in tree further by adding debug info tests for the
reinit copyable/addressonly cases in the multi-block case.
The new utility, to be run as part of copy propagation, hoists
destroy_values of owned lexical values up to deinit barriers. It is
heavily based on the rewritten ShrinkBorrowScope.
Replaced ShrinkBorrowScope's own data flow with the general
BackwardReachability.
Took this opportunity to refactor and document the utility.
Taken together these changes make ShrinkBorrowScope serve as a template
for a future LexicalDestroyHoisting which will operate on owned lexical
values (rather than guaranteed as here) and hoist destroy_values (rather
than end_borrows as here) but should otherwise be quite similar.
Previously, Reachability assumed that phis were not barriers. Here,
handling for barrier phis is added. To that end, a new delegate
callback `checkReachableBarrier(PhiValue)` is added. Before marking the
beginning of a block as reached (or any of its predecessors), check
whether each argument that is a phi is a barrier. If any is, then
reachability is done.
Implemented the new method in SSADestroyHoisting by splitting apart the
classification of an instruction and the work to do in response to
visiting an instruction. Then, when visiting a PhiValue, just check
whether any of the predecessors terminators are classified as barriers.
That way, seeing that they're classified that way doesn't result in
noting down that those terminators had been reached (which indeed they
will not have been if any of the terminators from which the values are
flowing into the phi are barriers).
RAUWing a lexical value with a non-lexical value is illegal because it
would result in the value's lifetime being shortened without regard to
deinit barriers. RAUWing _with_ a lexical value is LEGAL so long as
doing so doesn't extend its lifetime.
* Add the possibility to bisect the individual transforms of SILCombine and SimplifyCFG.
To do so, the `-sil-opt-pass-count` option now accepts the format `<n>.<m>`, where `m` is the sub-pass number.
The sub-pass number limits the number of individual transforms in SILCombine or SimplifyCFG.
* Add an option `-sil-print-last` to print the SIL of the currently optimized function before and after the last pass, which is specified with `-sil-opt-pass-count`.
C++ closures can implicitly malloc.
Avoid this by just capturing `this` and nothing else.
Reduces the time spent in the SIL pass pipeline by 25% when compiling the stdlib core.
rdar://88567996
The new utility folds patterns like
TOP:
// %borrowee is some owned value
%lifetime = begin_borrow %borrowee
BOTTOM:
// %copy is some transitive copy of %borrowee
apply %f(%copy)
end_borrow %lifetime
destroy_value %borrowee
into
TOP:
%move = move_value [lexical] %borrowee
%lifetime begin_borrow [lexical] %move
BOTTOM:
end_borrow %lifetime
apply %f(%move)
It is intended to be run after ShrinkBorrowScope moves the end_borrow up
to just before a relevant apply and after CanonicalizeOSSALifetime moves
destroy_value instructions up to just after their last guaranteed use,
at which point these patterns will exist.
Pulled out a simple check--that CanonicalizeOSSALifetime now uses to
determine whether to continue hoisting a destroy_value instruction--into
a predicate that can be used by LexicalDestroyFolding.
Flow-isolation is a diagnostic SIL pass that finds
unsafe accesses to properties in initializers and
deinitializers that cannot gain isolation to otherwise
protect those accesses from concurrent modifications.
See SE-327 for more details about how and why it exists.
This commit includes changes and features like:
- The removal of the escaping-use restriction
- Flow-isolation that works properly with `defer` statements
- Flow-isolation with an emphasis on helpful diagnostics.
It also includes known issues like:
- Local / nonescaping functions are not analyzed by
flow-isolation, despite it being technically possible.
The main challenge in supporting it efficiently is that
such functions do not have a single exit-point, like
a `defer`. In particular, arbitrary functions can throw
so there are points where nonisolation should _not_ flow
out of the function at a call-site in the initializer, etc.
- The implementation of the flow-isolation pass is not
particularly memory efficient; it relies on BitDataflow
even though the particular flow problem is simple.
So, a more efficient implementation would be specialized for
this particular problem, etc.
There are also some changes to the Swift language itself: defer
will respect its context when deciding its property access kind.
Previously, a defer in an initializer would always access a stored
property through its accessor methods, instead of doing so directly
like its enclosing function might. This inconsistency is unfortunate,
so for Swift 6+ we make this consistent. For Swift 5, only a defer
in a function that is a member of the following kinds of types
will gain this consistency:
- an actor type
- any nominal type that is actor-isolated, excluding UnsafeGlobalActor.
These types are still rather new, so there is much less of a chance of
breaking expected behaviors around defer. In particular, the danger is
that users are relying on the behavior of defer triggering a property
observer within an init or deinit, when it would not be triggering it
without the defer.
This optimizes keypath-closures, like
```
a.map { \.x }
```
It results in a significant performance improvement for such code patterns.
rdar://87968067
Squashed commit of the following:
commit e5a05ffe44
Author: Konrad `ktoso` Malawski <konrad_malawski@apple.com>
Date: Thu Jan 27 17:45:31 2022 +0900
cleanup
commit 1f751cea5a
Author: Konrad `ktoso` Malawski <konrad_malawski@apple.com>
Date: Thu Jan 27 14:50:33 2022 +0900
cleanups
commit c632f3215d
Author: Konrad `ktoso` Malawski <konrad_malawski@apple.com>
Date: Thu Jan 27 14:01:09 2022 +0900
add test for generic from actor decl
commit 09b8bd50a7
Author: Konrad `ktoso` Malawski <konrad_malawski@apple.com>
Date: Thu Jan 27 14:00:58 2022 +0900
cleanups
commit 31f4d0cffd
Author: Konrad `ktoso` Malawski <konrad_malawski@apple.com>
Date: Thu Jan 27 11:40:51 2022 +0900
fix test
commit ad4db2fb6c
Merge: 97227edcca07e2dfda56
Author: Konrad `ktoso` Malawski <konrad_malawski@apple.com>
Date: Wed Jan 26 23:31:41 2022 +0900
Merge branch 'main' into wip-zzz
commit 97227edcca
Author: Konrad `ktoso` Malawski <konrad_malawski@apple.com>
Date: Wed Jan 26 21:01:25 2022 +0900
remove @_dynamic methods!
fix tests
commit 1c79344dbb
Author: Konrad `ktoso` Malawski <konrad_malawski@apple.com>
Date: Wed Jan 19 12:51:09 2022 +0900
cleanup
wip
stuck
fixed the stack cleanups
cleanups pretty good now
weird load
rki
works
remove hack
add take + throw + return
fix test
more tests fixed
more tests fixed
more tests fixed
commit 3ed494c175
Author: Konrad `ktoso` Malawski <konrad_malawski@apple.com>
Date: Tue Jan 18 21:09:28 2022 +0900
stack issues in SIL verification
commit 5cf43a7f86
Author: Konrad `ktoso` Malawski <konrad_malawski@apple.com>
Date: Tue Jan 18 09:19:51 2022 +0900
about to call the remoteCall
goot to return, but missing subs
commit df8e47122a
Author: Konrad `ktoso` Malawski <konrad_malawski@apple.com>
Date: Thu Jan 13 14:09:49 2022 +0900
[Distributed] Refactor Invocation to Decoder/Encoder
getting there
done-recording
working on the string init
stuck trying to get String initializer SILFunction
created the remote call target
commit fc7bd62f32
Author: Konrad `ktoso` Malawski <konrad_malawski@apple.com>
Date: Wed Jan 12 23:01:14 2022 +0900
[Distributed] Pass arguments from Invocation to HBuffer
commit cafc2cc058
Author: Konrad `ktoso` Malawski <konrad_malawski@apple.com>
Date: Wed Jan 12 22:08:47 2022 +0900
works
commit a7d01837ff
Author: Pavel Yaskevich <pyaskevich@apple.com>
Date: Tue Jan 11 15:48:58 2022 -0800
[Distributed] Adjust interface of `swift_distributed_execute_target`
Since this is a special function, `calleeContext` doesn't point to
a direct parent but instead both parent context (uninitialized)
and resume function are passed as last arguments which means that
`callContext` has to act as an intermediate context in call to accessor.
commit c1f830be27
Author: Pavel Yaskevich <pyaskevich@apple.com>
Date: Tue Jan 11 17:00:08 2022 -0800
[Distributed] Drop optionality from result buffer in `_executeDistributedTarget`
`RawPointer?` is lowered into a two arguments since it's a struct,
to make it easy let's just allocate an empty pointer for `Void` result.
commit c83c2c37b6
Author: Pavel Yaskevich <pyaskevich@apple.com>
Date: Tue Jan 11 17:02:45 2022 -0800
[Distributed] NFC: Update _remoteCall test-case to check multiple different result types
commit 29e7cf50e4
Author: Konrad `ktoso` Malawski <konrad_malawski@apple.com>
Date: Wed Jan 12 21:32:37 2022 +0900
wip
commit 9128ecc6f8
Author: Konrad `ktoso` Malawski <konrad_malawski@apple.com>
Date: Wed Jan 12 20:46:20 2022 +0900
wip
commit a6b2a62a67
Author: Konrad `ktoso` Malawski <konrad_malawski@apple.com>
Date: Wed Jan 12 20:38:22 2022 +0900
wip
commit 8b188f0d43
Author: Konrad `ktoso` Malawski <konrad_malawski@apple.com>
Date: Wed Jan 12 16:55:10 2022 +0900
wip
commit 3796bec2b9
Author: Konrad `ktoso` Malawski <konrad_malawski@apple.com>
Date: Wed Jan 12 16:55:02 2022 +0900
wip
commit 0ffc68b5ef
Author: Konrad `ktoso` Malawski <konrad_malawski@apple.com>
Date: Tue Jan 11 21:44:58 2022 +0900
[Distributed] Implementing ad-hoc protocol requirements
commit 78862575e4
Author: Konrad `ktoso` Malawski <konrad_malawski@apple.com>
Date: Thu Jan 6 18:03:54 2022 +0900
cleanup
commit 5f4ab89e25
Merge: 24a628e7c0fdda6f2ee4
Author: Konrad `ktoso` Malawski <konrad_malawski@apple.com>
Date: Thu Jan 6 15:51:39 2022 +0900
Merge branch 'main' into wip-impl-execute-swift
commit 24a628e7c0
Author: Konrad `ktoso` Malawski <konrad_malawski@apple.com>
Date: Thu Jan 6 15:33:21 2022 +0900
wip
commit 69e7fed09d
Author: Konrad `ktoso` Malawski <konrad_malawski@apple.com>
Date: Wed Dec 22 06:36:45 2021 +0900
[Distributed] comment out distributed_actor_remoteCall for now
commit 376733a9f6
Author: Konrad `ktoso` Malawski <konrad_malawski@apple.com>
Date: Tue Dec 21 16:00:06 2021 +0900
reimplement distributed get type info impls
commit 74ab47886a
Author: Konrad `ktoso` Malawski <konrad_malawski@apple.com>
Date: Wed Dec 15 21:37:08 2021 +0900
[Distributed] Implement func metadata and executeDistributedTarget
dont expose new entrypoints
able to get all the way to calling _execute
The `run-unit-tests` is a "pseudo" pass which is invoked from sil-opt and runs all the unit tests, implemented in Swift.
This is done from the `swift-unit-tests.sil` lit test.
* add `BasicBlockSet`
* add `BasicBlockWorklist`
* add `BasicBlockRange`, which defines a range of blocks from a common dominating “begin” block to a set of “end” blocks.
* add `InstructionRange`, which is similar to `BasicBlockRange`, just on instruction level. It can be used for value lifetime analysis.
* rename `StackList` -> `Stack` and move it to `Optimizer/DataStructures`
* rename `PassContext.passContext` to `PassContext._bridged`
* add notify-functions to PassContext
Introduce a new instruction `dealloc_stack_ref ` and remove the `stack` flag from `dealloc_ref`.
The `dealloc_ref [stack]` was confusing, because all it does is to mark the deallocation of the stack space for a stack promoted object.
And a few other small related changes:
* remove libswiftPassInvocation from SILInstructionWorklist (because it's not needed)
* replace start/finishPassRun with start/finishFunction/InstructionPassRun
NFC
Extract and rewrite the destroy hoisting algorithm originally from
CopyForwarding (in 2014).
This is now a light-weight utility for hoisting destroy_addr
instructions. Shrinking an object's memory lifetime can allow removal
of copy_addr and other optimization.
This is extremely low-overhead and can run at any optimization level
without dependency on any analysis.
This algorithm is:
- Incremental
- SSA-based
- Canonical
- Free from alias analysis
See file-level comments.
The immediate purpose is to specify and test the constraints
introduced by adding lexical variable lifetimes to SIL semantics. It
can be used as a template for end_borrow hoisting.
Ultimately, this utility can be invoked within any pass that needs to
optimize a particular uniquely identified address. It will be used to
remove much of the complexity from CopyForwarding.
Pessimistic, non-iterative data flow for analyzing backward reachability
from a set of last uses to their dominating def or nearest barrier.
Meet: ReachableEnd(predecessor) = intersection(ReachableBegin, successors)
Intended for frequently called utilities where minimizing the cost of
data flow is more important than analyzing reachability across
loops. Expected to visit very few blocks because barriers often occur
close to a last use.
Note: this does not require initializing bitsets for all blocks in the
function for each SSA value being analyzed.
* rename the CrossModuleSerializationSetup pass to simply CrossModuleOptimization
* remove the CMO specific serializer pass. Instead run the CrossModuleSerializationSetup pass directly before the standard serializer pass.
* correctly handle shared functions (e.g. specializations)
* refactoring
So that CopyPropagation and other clients can react accordingly, pass
back a list of copy_value instructions that were rewritten by
ShrinkBorrowScope. In CopyPropagation, add each modified copy to the
copy worklist.
