Enhance the utility with the ability to end lifetimes of lexical values
at indicated instructions, overriding the usual behavior of maintaining
such lifetimes' previous endpoints (modulo non-deinit-barrier
instructions).
I was originally hoping to reuse mark_must_check for multiple types of checkers.
In practice, this is not what happened... so giving it a name specifically to do
with non copyable types makes more sense and makes the code clearer.
Just a pure rename.
llvm::SmallSetVector changed semantics
(https://reviews.llvm.org/D152497) resulting in build failures in Swift.
The old semantics allowed usage of types that did not have an
`operator==` because `SmallDenseSet` uses `DenseSetInfo<T>::isEqual` to
determine equality. The new implementation switched to using
`std::find`, which internally uses `operator==`. This type is used
pretty frequently with `swift::Type`, which intentionally deletes
`operator==` as it is not the canonical type and therefore cannot be
compared in normal circumstances.
This patch adds a new type-alias to the Swift namespace that provides
the old semantic behavior for `SmallSetVector`. I've also gone through
and replaced usages of `llvm::SmallSetVector` with the
`Swift::SmallSetVector` in places where we're storing a type that
doesn't implement or explicitly deletes `operator==`. The changes to
`llvm::SmallSetVector` should improve compile-time performance, so I
left the `llvm::SmallSetVector` where possible.
As part of SE-390, you're required to write either:
- `consume self`
- pass self as a `consuming` parameter to a function
- `discard self`
before the function ends in a context that contains a
`discard self` somewhere. This prevents people from accidentally
invoking the deinit due to implicit destruction of `self` before
exiting the function.
rdar://106099027
Previously, the utility bailed out on lexical lifetimes because it
didn't respect deinit barriers. Here, deinit barriers are found and
added to liveness if the value is lexical. This enables copies to be
propagated without hoisting destroys over deinit barriers.
rdar://104630103
Use BasicBlockBitfield to record per-block liveness state. This has
been the intention since BasicBlockBitfield was first introduced.
Remove the per-field bitfield from PrunedLiveBlocks. This
(re)specializes the data structure for scalar liveness and drastically
simplifies the implementation.
This utility is fundamental to all ownership utilities. It will be on
the critical path in many areas of the compiler, including at
-Onone. It needs to be minimal and as easy as possible for compiler
engineers to understand, investigate, and debug.
This is in preparation for fixing bugs related to multi-def liveness
as used by the move checker.
Otherwise, sometimes when the object checker emits a diagnostic and cleans up
the IR, some of the cleaned up copies are copies that should have been handled
by the address checker. The end result is that the address checker does not emit
diagnostics for that IR. I found this problem was exascerbated when writing code
for escaping closures.
This commit also cleans up the passes in preparation for at a future time moving
some of the transformations into the utils folder.
