The problem with `is_escaping_closure` was that it didn't consume its operand and therefore reference count checks were unreliable.
For example, copy-propagation could break it.
As this instruction was always used together with an immediately following `destroy_value` of the closure, it makes sense to combine both into a `destroy_not_escaped_closure`.
It
1. checks the reference count and returns true if it is 1
2. consumes and destroys the operand
Type annotations for instruction operands are omitted, e.g.
```
%3 = struct $S(%1, %2)
```
Operand types are redundant anyway and were only used for sanity checking in the SIL parser.
But: operand types _are_ printed if the definition of the operand value was not printed yet.
This happens:
* if the block with the definition appears after the block where the operand's instruction is located
* if a block or instruction is printed in isolation, e.g. in a debugger
The old behavior can be restored with `-Xllvm -sil-print-types`.
This option is added to many existing test files which check for operand types in their check-lines.
Optionally, the dependency to the initialization of the global can be specified with a dependency token `depends_on <token>`.
This is usually a `builtin "once"` which calls the initializer for the global variable.
* `alloc_vector`: allocates an uninitialized vector of elements on the stack or in a statically initialized global
* `vector`: creates an initialized vector in a statically initialized global
This instructions marks the point where all let-fields of a class are initialized.
This is important to ensure the correctness of ``ref_element_addr [immutable]`` for let-fields,
because in the initializer of a class, its let-fields are not immutable, yet.
Codegen is the same, but `begin_dealloc_ref` consumes the operand and produces a new SSA value.
This cleanly splits the liferange to the region before and within the destructor of a class.
It is necessary for opaque values where for casts that will newly start
out as checked_cast_brs and be lowered to checked_cast_addr_brs, since
the latter has the source formal type, IRGen relies on being able to
access it, and there's no way in general to obtain the source formal
type from the source lowered type.
The `bare` attribute indicates that the object header is not used throughout the lifetime of the value.
This means, no reference counting operations are performed on the object and its metadata is not used.
The header of bare objects doesn't need to be initialized.
The `bare` attribute indicates that the object header is not used throughout the lifetime of the object.
This means, no reference counting operations are performed on the object and its metadata is not used.
The header of bare objects doesn't need to be initialized.
This instruction can be inserted by Onone optimizations as a replacement for deleted instructions to
ensure that it's possible to single step on its location.
This lets us write optimizer unit tests and selectively debug the
optimizer in general. We'll be able trace analyses and control
optimization selectively for certain values.
Adding a trace flag to debug_value is the easiest way to start using
it experimentally and develop the rest of the infrastructure. If this
takes off, then we can consider a new `trace_value`
instruction. For now, reusing debug_value is the least intrusive way to
start writing liveness unit tests.
The old syntax was
@opened("UUID") constraintType
Where constraintType was the right hand side of a conformance requirement.
This would always create an archetype where the interface type was `Self`,
so it couldn't cope with member types of opened existential types.
Member types of opened existential types is now a thing with SE-0309, so
this lack of support prevented writing SIL test cases using this feature.
The new syntax is
@opened("UUID", constraintType) interfaceType
The interfaceType is a type parameter rooted in an implicit `Self`
generic parameter, which is understood to be the underlying type of the
existential.
Fixes rdar://problem/93771238.
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.
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.
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
Required for UnsafeRawPointer.withMemoryRebound(to:)
%token = bind_memory %0 : $Builtin.RawPointer, %1 : $Builtin.Word to $T
%0 must be of $Builtin.RawPointer type
%1 must be of $Builtin.Word type
%token is an opaque $Builtin.Word representing the previously bound types
for this memory region.
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 patch replace all in-memory objects of DebugValueAddrInst with
DebugValueInst + op_deref, and duplicates logics that handles
DebugValueAddrInst with the latter. All related check in the tests
have been updated as well.
Note that this patch neither remove the DebugValueAddrInst class nor
remove `debug_value_addr` syntax in the test inputs.
If the '[poison]' flag is set, then all references within this debug
value will be overwritten with a sentinel at this point in the
program. This is used in debug builds when shortening non-trivial
value lifetimes to ensure the debugger cannot inspect invalid
memory. `debug_value` instructions with the poison flag are not
generated until OSSA islowered. They are not expected to be serialized
within the module, and the pipeline is not expected to do any
significant code motion after lowering.
While removing an invalid cast and inserting traps, we are currently
inserting a store of undef to the cast destination and delete all
instructions after the cast except for dealloc_stack.
If the cast destination was an alloc_stack, the verifier could raise
an error saying the cast destination was initialized at the dealloc.
This PR deletes the store to undef, destroy_addr of the cast src,
and gets rid of the code that was retaining the dealloc_stack.
None of this is necessary anymore and the SIL is going to be legal
because we insert unreachable instruction.
Specifically, I made it so that assuming our instruction is inserted into a
block already that we:
1. Return a constraint of {OwnershipKind::Any, UseLifetimeConstraint::NonLifetimeEnding}.
2. Return OwnershipKind::None for all values.
Noticed above I said that if the instruction is already inserted into a block
then we do this. The reason why is that if this is called before an instruction
is inserted into a block, we can't get access to the SILFunction that has the
information on whether or not we are in OSSA form. The only time this can happen
is if one is using these APIs from within SILBuilder since SILBuilder is the
only place where we allow this to happen. In SILBuilder, we already know whether
or not our function is in ossa or not and already does different things as
appropriate (namely in non-ossa does not call getOwnershipKind()). So we know
that if these APIs are called in such a situation, we will only be calling it if
we are in OSSA already. Given that, we just assume we are in OSSA if we do not
have a function.
To make sure that no mistakes are made as a result of that assumption, I put in
a verifier check that all values when ownership is disabled return a
OwnershipKind::None from getOwnershipKind().
The main upside to this is this means that we can write code for both
OSSA/non-OSSA and write code for non-None ownership without needing to check if
ownership is enabled.
The ``base_addr_for_offset`` instruction creates a base address for offset calculations.
The result can be used by address projections, like ``struct_element_addr``, which themselves return the offset of the projected fields.
IR generation simply creates a null pointer for ``base_addr_for_offset``.
Private and internal classes shouldn't have ABI constraints on their concrete vtable layout, so if methods
don't have overrides in practice, we can elide their vtable entries.
* a new [immutable] attribute on ref_element_addr and ref_tail_addr
* new instructions: begin_cow_mutation and end_cow_mutation
These new instructions are intended to be used for the stdlib's COW containers, e.g. Array.
They allow more aggressive optimizations, especially for Array.
SIL type lowering erases DynamicSelfType, so we generate
incorrect code when casting to DynamicSelfType. Fixing this
requires a fair amount of plumbing, but most of the
changes are mechanical.
Note that the textual SIL syntax for casts has changed
slightly; the target type is now a formal type without a '$',
not a SIL type.
Also, the unconditional_checked_cast_value and
checked_cast_value_br instructions now take the _source_
formal type as well, just like the *_addr forms they are
intended to replace.
This removes it from the AST and largely replaces it with AnyObject
at the SIL and IRGen layers. Some notes:
- Reflection still uses the notion of "unknown object" to mean an
object with unknown refcounting. There's no real reason to make
this different from AnyObject (an existential containing a
single object with unknown refcounting), but this way nothing
changes for clients of Reflection, and it's consistent with how
native objects are represented.
- The value witness table and reflection descriptor for AnyObject
use the mangling "BO" instead of "yXl".
- The demangler and remangler continue to support "BO" because it's
still in use as a type encoding, even if it's not an AST-level
Type anymore.
- Type-based alias analysis for Builtin.UnknownObject was incorrect,
so it's a good thing we weren't using it.
- Same with enum layout. (This one assumed UnknownObject never
referred to an Objective-C tagged pointer. That certainly wasn't how
we were using it!)
This flag is set by DefinitInitialization if the lifetime of the stored value is controlled dynamically.
If the flag is set, it's not (easily) possibly to statically calculate the lifetime of the stored value.
