The typedef `swift::Module` was a temporary solution that allowed
`swift::Module` to be renamed to `swift::ModuleDecl` without requiring
every single callsite to be modified.
Modify all the callsites, and get rid of the typedef.
For this we need to store the linkage of the “original” method implementation in the vtable.
Otherwise DeadFunctionElimination thinks that the method implementation is not public but private (which is the linkage of the thunk).
The big part of this change is to extend SILVTable to store the linkage (+ serialization, printing, etc.).
fixes rdar://problem/29841635
Previously all of the following would strip off varying amounts of
MetatypeType, LValueType, InOutType, DynamicSelfType, etc:
- ConstraintSystem::performMemberLookup()
- ConstraintSystem::lookupMember()
- TypeChecker::lookupMember()
- DeclContext::lookupQualified()
- Type::getContextSubstitutions()
The problem is that the higher level methods that took a lookup type
would call the lower level methods, and post-process the result using
the given lookup type. Since different levels of sugar were stripped,
it made the code hard to reason about and opened up edge cases, eg
if a DynamicSelfType or InOutType appears where we didn't expect it.
Since filtering out static/instance and mutating/nonmutating members
is done at higher levels, there's no reason for these name lookup
operations to accept anything other than nominal types, existentials
and archetypes.
Make this so with assertions, and deal with the fallout.
In a generic signature like <T, U where T.A == U>, there is only
one primary archetype, 'T'. 'U' will not appear in SubstitutionMaps,
and the SubstitutionMap version of Type::subst() cannot handle an
interface type containing 'U'.
For interface types, there are two levels of canonicalization:
- The AST-level getCanonicalType() which strips away sugar
- The GenericSignature-level getCanonicalTypeInContext() which
replaces each interface type in an equivalence class with a
representative
SILFunctionTypes must be canonical with respect to a generic
signature.
When emitting re-abstraction thunks we could end up constructing
a SILFunctionType containing 'U', because we were calling
getCanonicalType() on the result of mapTypeOutOfContext().
Fix this by making sure to use getCanonicalTypeInContext() on
the result of mapTypeOutOfContext(), just as we do in capture
lowering.
Unfortunately I worry this problem will come up again in a
different form -- a more general fix would change
mapTypeOutOfContext() to always return "generic signature
canonical" types, and also fix SubstitutionMaps to understand
same type constraints better.
Fixes <https://bugs.swift.org/browse/SR-3326>.
Suppose we have a protocol requirement returning Self:
protocol Clonable {
func clone() -> Self
}
If we have a value 'x' of existential type 'Clonable',
the partial application 'x.clone' has formal type
'() -> Clonable'. However the actual type of the
method substitutes in an "opened" existential type
for 'Self'.
In order to implement the partial application we must
wrap the method in a thunk which 'erases' the opened
existential, so the thunk has type
<T : Clonable> (() -> T) -> () -> Clonable
The thunk is called with a substitution replacing 'T'
with the opened existential type.
Fixes <rdar://problem/21391055>.
Swift admits implicit conversions between tuple types to
introduce and eliminate argument labels, and re-order
argument labels. These are expressed as TupleShuffleExpr
in the AST.
SILGen has two different code paths for lowering TupleShuffleExpr,
which is also used for varargs and default arguments in call
argument emission.
These two code paths support different subsets of TupleShuffleExpr;
neither one supports the full generality of the other, but there
is some overlap.
Work around the damage by routing the two different "kinds" of
TupleShuffleExprs to the correct place in argument emission.
The next incremental step here would be to refactor ArgEmitter to
make it usable when lowering SubscriptExpr; then the RValueEmitter's
support for varargs in TupleShuffleExpr can go away. Once that's
done we can split off an ArgumentExpr from TupleShuffleExpr, and
in the fullness of time, fold ArgumentExpr into ApplyExpr.
At that point this dark corner of the AST will start to be sane...
Fixes <https://bugs.swift.org/browse/SR-2887>.
Otherwise we might miss emitting a local type that's inside
unreachable code. Normally such a type cannot be found via
name lookup either, but IRGen will walk the list of local types
and try to emit a class with no SIL vtable, which will crash.
Fixes <https://bugs.swift.org/browse/SR-1924>.
Recursive references of computed properties are allowed, but warned
about. Closures `var`s built like the one in 28396 should crash at
runtime, not crash the compiler.
The full design would require wrapping the nonescaping closure in an escapable box, and testing that box for uniqueness at the end of the evaluation, but for now just do the moral equivalent of a bitcast to make the functionality available to users and let us deprecate `unsafeBitCast`-ing for this purpose.
withoutActuallyEscaping has a signature like `<T..., U, V, W> (@nonescaping (T...) throws<U> -> V, (@escaping (T...) throws<U> -> V) -> W) -> W, but our type system for functions unfortunately isn't quite that expressive yet, so we need to special-case it. Set up the necessary type system when resolving an overload set to reference withoutActuallyEscaping, and if a type check succeeds, build a MakeTemporarilyEscapableExpr to represent it in the type-checked AST.
Fixes rdar://21782689: "Swift over-releases NSString when bridging".
The NSString -> String bridging function takes its input at +1 (@owned),
but the compiler seemed to be assuming it should be +0. The solution is
to make the compiler do a proper copy, rather than a borrow.
- The DeclContext versions of these methods have equivalents
on the DeclContext class; use them instead.
- The GenericEnvironment versions of these methods are now
static methods on the GenericEnvironment class. Note that
these are not made redundant by the instance methods on
GenericEnvironment, since the static methods can also be
called with a null GenericEnvironment, in which case they
just assert that the type is fully concrete.
- Remove some unnecessary #includes of ArchetypeBuilder.h
and GenericEnvironment.h. Now changes to these files
result in a lot less recompilation.
We preserve the current behavior of assuming Any ownership always and use
default arguments to hide this change most of the time. There are asserts now in
the SILBasicBlock::{create,replace,insert}{PHI,Function}Argument to ensure that
the people can only create SILFunctionArguments in entry blocks and
SILPHIArguments in non-entry blocks. This will ensure that the code in tree
maintains the API distinction even if we are not using the full distinction in
between the two.
Once the verifier is finished being upstreamed, I am going to audit the
createPHIArgument cases for the proper ownership. This is b/c I will be able to
use the verifier to properly debug the code. At that point, I will also start
serializing/printing/parsing the ownershipkind of SILPHIArguments, but lets take
things one step at a time and move incrementally.
In the process, I also discovered a CSE bug. I am not sure how it ever worked.
Basically we replace an argument with a new argument type but return the uses of
the old argument to refer to the old argument instead of a new argument.
rdar://29671437
Rename the old getMemberSubstitutions() to getContextSubstitutions()
and add a new getMemberSubstitutions() that takes a ValueDecl, rather
than the member's DeclContext.
This new method forwards generic parameters if the member is a generic
function.
Officially kick SILBoxType over to be "nominal" in its layout, with generic layouts structurally parameterized only by formal types. Change SIL to lower a capture to a nongeneric box when possible, or a box capturing the enclosing generic context when necessary.
Changes:
* Terminate all namespaces with the correct closing comment.
* Make sure argument names in comments match the corresponding parameter name.
* Remove redundant get() calls on smart pointers.
* Prefer using "override" or "final" instead of "virtual". Remove "virtual" where appropriate.
The substitution only replaces archetypes with abstract generic parameters, so no conformance lookup is necessary, and we can provide a "lookup" callback now that just vends abstract conformances.
(Ideally, we'd be able to do this for mapTypeIntoContext too, but we run into problems with generic signatures with same-type constraints on associated types with protocol requirements. Mapping `t_0_0.AssocType` into such a context will require conformance lookup for the concrete type replacement, since same-type Requirements don't preserve the conformances that satisfy the protocol requirements for the same-type relationship.)
This simplifies the SILType substitution APIs and brings them in line with Doug and Slava's refactorings to improve AST-level type substitution. NFC intended.
