Specifically this means that rather than always being owned, we now have owned
and guaranteed versions of copyable_to_moveonlywrapper. Similar to
moveonlywrapper_to_copyable, one chooses which variant one gets by using
specific SILBuilder APIs:
create{Owned,Guaranteed}CopyableToMoveOnlyWrapperValueInst. It is still
forwarding and the rest of the forwarding APIs work as expected except that the
forwarding ownership is fixed (and an assertion will result if one attempts to
do so).
NOTE: It is assumed that trivial operands are always passed to the owned
variant.
These instructions have the following attributes:
1. copyably_to_moveonlywrapper takes in a 'T' and maps it to a '@moveOnly
T'. This is semantically used when initializing a new moveOnly binding from a
copyable value. It semantically destroys its input @owned value and returns a
brand new independent @owned @moveOnly value. It also is used to convert a
trivial copyable value with type 'Trivial' into an owned non-trivial value of
type '@moveOnly Trivial'. If one thinks of '@moveOnly' as a monad, this is how
one injects a copyable value into the move only space.
2. moveonlywrapper_to_copyable takes in a '@moveOnly T' and produces a new 'T'
value. This is a 'forwarding' instruction where at parse time, we only allow for
one to choose it to be [owned] or [guaranteed].
* moveonlywrapper_to_copyable [owned] is used to signal the end of lifetime of
the '@moveOnly' wrapper. SILGen inserts these when ever a move only value has
its ownership passed to a situation where a copyable value is needed. Since it
is consuming, we know that the no implicit copy checker will ensure that if we
need a copy for it, the program will emit a diagnostic.
* moveonlywrapper_to_copyable [guaranteed] is used to pass a @moveOnly T value
as a copyable guaranteed parameter with type 'T' to a function. In the case of
using no-implicit-copy checking this is always fine since no-implicit-copy is a
local pattern. This would be an error when performing no escape
checking. Importantly, this instruction also is where in the case of an
@moveOnly trivial type, we convert from the non-trivial representation to the
trivial representation.
Some important notes:
1. In a forthcoming commit, I am going to rebase the no implicit copy checker on
top of these instructions. By using '@moveOnly' in the type system, we can
ensure that later in the SIL pipeline, we can have optimizations easily ignore
the code.
2. Be aware of is that due to SILGen only emitting '@moveOnly T' along immediate
accesses to the variable and always converts to a copyable representation when
calling other code, we can simply eliminate from the IR all moveonly-ness from
the IR using a lowering pass (that I am going to upstream). In the evil scheme
we are accomplishing here, we perform lowering of trivial values right after
ownership lowering and before diagnostics to simplify the pipeline.
On another note, I also fixed a few things in SILParsing around getASTType() vs
getRawASTType().
We didn't serialize the ownership kind, which resulted in a miscompile causing an over-release.
The unchecked_ref_cast is the only instruction for which we change the ownership in the optimizer, so that it doesn't match the operand's ownership. Therefore this fix is sufficient for now - we don't need to serialize the ownership of other instructions.
But this is really a design flaw of the `OwnershipForwardingMixin`. It should not allow to set the ownership to arbitrary values.
rdar://92696202
- Add a `[reflection]` bit to `alloc_box` instructions, to indicate that a box
should be allocated with reflection metadata attached.
- Add a `@captures_generics` attribute to SILLayouts, to indicate a type layout
that captures the generic arguments it's substituted with, meaning it can
recreate the generic environment without additional ABI-level arguments, like
a generic partial application can.
The main point of this change is to make sure that a shared function always has a body: both, in the optimizer pipeline and in the swiftmodule file.
This is important because the compiler always needs to emit code for a shared function. Shared functions cannot be referenced from outside the module.
In several corner cases we missed to maintain this invariant which resulted in unresolved-symbol linker errors.
As side-effect of this change we can drop the shared_external SIL linkage and the IsSerializable flag, which simplifies the serialization and linkage concept.
We now schedule conformance emissions in basically the same way
we do for types and declarations, which means that we'll emit them
uniquely in the module file instead of redundantly at every use.
This should produce substantially smaller module files overall,
especially for modules that heavily use generics. It also means
that we can remove all the unfortunate code to support using
different abbrev codes for them in different bitcode blocks.
Requirement lists are now emitted inline in the records that need
them instead of as trailing records. I think this will improve
space usage, but mostly it assists in eliminating the problem
where abbrev codes are shared between blocks.
Reduces the number of _ContiguousArrayStorage metadata.
In order to support constant time bridging we do need to set the correct
metadata when we bridge to Objective-C. This is so that the type check
succeeds when bridging back from Objective-C to reuse the storage
instance rather than bridging the elements.
To support dynamically setting the `_ContiguousArrayStorage` element
type i needed to add support for optimizing `alloc_ref_dynamic`
throughout the optimizer.
Possible future improvements:
* Use different metadata such that we can disambiguate native Swift
classes during destruction -- allowing native release rather then unknown
release usage.
* Optimize the newly added semantic function
getContiguousArrayStorageType
rdar://86171143
The main effect of this will be that in IRGen we will use llvm.dbg.addr instead
of llvm.dbg.declare. We must do this since llvm.dbg.declare implies that the
given address is valid throughout the program.
This just adds the instructions/printing/parsing/serialization/deserialization.
rdar://85020571
This is an instruction that I am going to use to drive some of the ownership
based dataflow optimizations that I am writing now. The instruction contains a
kind that allows one to know what type of checking is required and allows the
need to add a bunch of independent instructions for independent checkers. Each
checker is responsible for removing all of its own mark instructions. NOTE:
MarkMustCheckInst is only allowed in Raw SIL since once we are in Canonical SIL
we want to ensure that all such checking has already occurred.
Store a list of argument effects in a function, which specify if and how arguments escape.
Such effects can be specified in the Swift source code (for details see docs/ReferenceGuides/UnderscoredAttributes.md) or derived in an optimization pass.
For details see the documentation in SwiftCompilerSources/Sources/SIL/Effects.swift.
The new flag will be used to track whether a move_value corresponds to a
source-level lexical scope. Here, the flag is just added to the
instruction and represented in textual and serialized SIL.
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.
This instruction is similar to a copy_addr except that it marks a move of an
address that has to be checked. In order to keep the memory lifetime verifier
happy, the semantics before the checker runs are the mark_unresolved_move_addr is
equivalent to copy_addr [init] (not copy_addr [take][init]).
The use of this instruction is that Mandatory Inlining converts builtin "move"
to a mark_unresolved_move_addr when inlining the function "_move" (the only
place said builtin is invoked).
This is then run through a special checker (that is later in this PR) that
either proves that the mark_unresolved_move_addr can actually be a move in which
case it converts it to copy_addr [take][init] or if it can not be a move, emit
an error and convert the instruction to a copy_addr [init]. After this is done
for all instructions, we loop back through again and emit an error on any
mark_unresolved_move_addr that were not processed earlier allowing for us to
know that we have completeness.
NOTE: The move kills checker for addresses is going to run after Mandatory
Inlining, but before predictable memory opts and friends.
Required for UnsafeRawPointer.withMemoryReboud(to:).
%out_token = rebind_memory %0 : $Builtin.RawPointer to %in_token
%0 must be of $Builtin.RawPointer type
%in_token represents a cached set of bound types from a prior memory state.
%out_token is an opaque $Builtin.Word representing the previously bound
types for this memory region.
This instruction's semantics are identical to ``bind_memory``, except
that the types to which memory will be bound, and the extent of the
memory region is unknown at compile time. Instead, the bound-types are
represented by a token that was produced by a prior memory binding
operation. ``%in_token`` must be the result of bind_memory or
This is a signal to the move value kill analysis that this is a move that should
have diagnostics emitted for it. It is a temporary addition until we add
MoveOnly to the SIL type system.
I am purposely doing this in SILGen rather than at the type system level to
avoid having to have to add a bunch of boilerplate to the type system. Instead
of doing that, I am in SILGen checking for the isNoImplicitCopy bit on the
ParamDecl when we emit arguments. At that point, I set on the specific
SILArgument being emitted the bit that it is no implicit copy. In terms of
printing at the SIL level, I just printed it in front of the function argument
type like @owned, e.x.:
func myFunc(_ x: @_noImplicitCopy T) -> T {
...
}
becomes:
bb0(%0 : @noImplicitCopy @owned $T):
Some notes:
* Just to be explicit, I am making it so that no implicit copy parameters by
default are always passed at +1. The reason why I think this makes sense is
that this is the natural way of working with a move only value.
* As always, one can not write no implicit copy the attribute without passing
the flag -enable-experimental-move-only so this is NFC.
rdar://83957088
The key thing is that the move checker will not consider the explicit copy value
to be a copy_value that can be rewritten, ensuring that any uses of the result
of the explicit copy_value (consuming or other wise) are not checked.
Similar to the _move operator I recently introduced, this is a transparent
function so we can perform one level of specialization and thus at least be
generic over all concrete types.
This was a relict from the -sil-serialize-all days. This linkage doesn't make any sense because a private function cannot be referenced from another module (or file, in case of non-wmo compilation).
Changed the frontend flag to -enable-experimental-lexical-lifetimes from
-enable-experimental-defined-lifetimes.
Changed the attribute on begin_borrow from [defined] to [lexical].
The new flag will be used to track whether a borrow scope corresponds to
a source-level lexical scope. Here, the flag is just documented, added
to the instruction, represented in textual and serialized SIL, and
cloned.
Support for addresses with arbitrary alignment as opposed to their
element type's natural in-memory alignment.
Required for bytestream encoding/decoding without resorting to memcpy.
SIL instruction flag, documentation, printing, parsing, serialization,
and IRGen.
This is a new instruction that can be used by SILGen to perform a semantic move
in between two entities that are considered separate variables at the AST
level. I am going to use it to implement an experimental borrow checker.
This PR contains the following:
1. I define move_value, setup parsing, printing, serializing, deserializing,
cloning, and filled in all of the visitors as appropriate.
2. I added createMoveValue and emitMoveValueOperation SILBuilder
APIs. createMoveValue always creates a move and asserts is passed a trivial
type. emitMoveValueOperation in contrast, will short circuit if passed a
trivial value and just return the trivial value.
3. I added IRGen tests to show that we can push this through the entire system.
This is all just scaffolding for the instruction to live in SIL land and as of
this PR doesn't actually do anything.
The new flag will be used to track whether a borrow scope corresponds to
a source-level lexical scope. Here, the flag is just added to the
instruction and represented in textual and serialized SIL.
This makes sure that all analysis will get the `notifyAddedOrModifiedFunction` notifications.
This fixes a crash in CallerAnalysis, which relies that it's notified for all newly created functions.
This is related to following bug reports for cross-module-optimization:
https://bugs.swift.org/browse/SR-15048
rdar://81701218
Although I believe that there are more bugs involved which need to be fixed.
Unfortunately I don't have a test case for this fix.
SILGen this builtin to a mandatory hop_to_executor with an actor type
operand.
e.g.
Task.detached {
Builtin.hopToActor(MainActor.shared)
await suspend()
}
Required to fix a bug in _runAsyncMain.
This showed up when trying to convert swift-package-manager to build
using static linking on Windows. We would not correctly identify the
module as being static due to there being no DeclContext for emission.
Instead, put the archetype->instrution map into SIlModule.
SILOpenedArchetypesTracker tried to maintain and reconstruct the mapping locally, e.g. during a use of SILBuilder.
Having a "global" map in SILModule makes the whole logic _much_ simpler.
I'm wondering why we didn't do this in the first place.
This requires that opened archetypes must be unique in a module - which makes sense. This was the case anyway, except for keypath accessors (which I fixed in the previous commit) and in some sil test files.
Through various means, it is possible for a synchronous actor-isolated
function to escape to another concurrency domain and be called from
outside the actor. The problem existed previously, but has become far
easier to trigger now that `@escaping` closures and local functions
can be actor-isolated.
Introduce runtime detection of such data races, where a synchronous
actor-isolated function ends up being called from the wrong executor.
Do this by emitting an executor check in actor-isolated synchronous
functions, where we query the executor in thread-local storage and
ensure that it is what we expect. If it isn't, the runtime complains.
The runtime's complaints can be controlled with the environment
variable `SWIFT_UNEXPECTED_EXECUTOR_LOG_LEVEL`:
0 - disable checking
1 - warn when a data race is detected
2 - error and abort when a data race is detected
At an implementation level, this introduces a new concurrency runtime
entry point `_checkExpectedExecutor` that checks the given executor
(on which the function should always have been called) against the
executor on which is called (which is in thread-local storage). There
is a special carve-out here for `@MainActor` code, where we check
against the OS's notion of "main thread" as well, so that `@MainActor`
code can be called via (e.g.) the Dispatch library's
`DispatchQueue.main.async`.
The new SIL instruction `extract_executor` performs the lowering of an
actor down to its executor, which is implicit in the `hop_to_executor`
instruction. Extend the LowerHopToExecutor pass to perform said
lowering.
