This is exactly like copy_addr except that it is not viewed from the verifiers
perspective as an "invalid" copy of a move only value. It is intended to be used
in two contexts:
1. When the move checker emits a diagnostic since it could not eliminate a copy,
we still need to produce valid SIL without copy_addr on move only types since we
will hit canonical SIL eventually even if we don't actually codegen the SIL. The
pass can just convert said copy_addr to explicit_copy_addr and everyone is
happy.
2. To implement the explicit copy function for address only types.
Andy some time ago already created the new API but didn't go through and update
the old occurences. I did that in this PR and then deprecated the old API. The
tree is clean, so I could just remove it, but I decided to be nicer to
downstream people by deprecating it first.
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.
The main fixes are:
1. MoveOnlyWrapperToCopyableValue needed to be marked as a
FirstArgOwnershipForwardingSingleValueInst instead of just as being an
Ownership mixin. I discovered that in certain cases I was treating it that
way (in the isa check for FirstArgOwnershipForwardingSingleValueInst), but we
were inconsistent. Now we are consistent.
2. MoveOnlyWrapperToCopyableValue is always specified as being initialized as
owned or guaranteed. What is key to understand though is that the
owned/guaranteed property here is more a semantic property around whether the
lifetime of the move only value is ending or if we are allowing it to escape
as an moveonlywrapped unwrapped guaranteed parameter to a function. The main
implication of this is that we can not just use the actual ownership kind to
determine the type of moveonlywrapper_to_copyable we are using. This is b/c
after ownership lowering, the resulting ownership kind will be none, meaning
the instruction will be in an invalid state. Thus the need to represent this
as a separate bit in the instruction. It may make sense to rename the forms
of this instruction to be `[lifetime end]` and `[guaranteed function arg]`
that way it is semantically clear. But I am going to do that change at
another time.
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().
The only place outside of SILType that uses getRawASTType() is in SILPrinter. It
is really an inner detail of SILType that we don't want to expose. With that in
mind, in this commit we:
1. Made SILType::getRawASTType() private.
2. Forward declared SILPrinter in SILType.h. We don't define it so no one can
use it, but the declaration still lets us make it a friend class of SILType
(allowing SILPrinter to still access getRawASTType()).
This is done by introducing the API SILType::getSemanticASTType(). This can be
used in contexts for type queries like getStructOrBoundGenericStruct() where one
wants to look through the move only wrapper to the underlying type.
`salvageDebugInfo` is called during SIL Mem2Reg and could produce misleading debug info in the following case:
```
%a = alloc_stack $MyModel.TangentVector, var, name "self", argno 1, implicit, loc "debug2.swift":37:17 ...
...
store %b to %a : $*MyModel.TangentVector
```
Such SIL could be created as a result of inlining (where store comes from the inlined function).
Before this patch we'd end with `debug_value` instruction with variable information, but without or incorrect location.
This caused LLVM IR debug info verifier assertions when there might be another instruction with complete debug info (including location) for the same argument.
After this patch we always reuse it from destination alloca
Fixes#58660
- 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.
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 optimizes keypath-closures, like
```
a.map { \.x }
```
It results in a significant performance improvement for such code patterns.
rdar://87968067
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).
Fix two bugs:
- FirstArgOwnershipForwardingSingleValueInst needs to forward its first operand.
- select_value needs to be a ForwardedBorrow for all cases and the default.
The AsyncEntryPoint represents the thunk that is wrapped in a task. This
thunk is used to ensure that the main function explicitly calls "exit",
and to properly unwrap and report any unhandled errors returned from the
user-written main. The function takes on the name `@async_main` in the
emitted SIL.
Changed the frontend flag to -enable-experimental-lexical-lifetimes from
-enable-experimental-defined-lifetimes.
Changed the attribute on begin_borrow from [defined] to [lexical].
