This structure contains all of the type information that we use to build a
ResultPlanPtr. In a subsequent commit, I am going to move ResultPlanPtr creation
out of emitApply and place it before the creation of arguments. This is to
enable indirect result initializations to belong to the scope outside of any
argument based scopes.
Without this the lifetimes of the indirect result initializations and arguments
can not be separated without using hacks. There is no reason why we can't emit
the indirect result temporaries before we emit any arguments since they will
remain dormant until after the final apply/any future committed argument scopes
being popped.
rdar://30955427
Change emitApplyOfLibraryIntrinsic() to take a SubstitutionMap,
and use the correct abstractions to build the map.
This gets rid of the last remaining uses of gatherAllSubstitutions()
in SIL.
Previously, we would put a destroy_value directly on the value that we tried to
cast. Since checked_cast_br is consuming, this would cause the destroy_value on
the failure path to be flagged as a double consume.
This commit causes SILGen to emit the value consumed by checked_cast_br as an
@owned argument to the failure BB, allowing semantic arc rules to be respected.
As an additional benefit, I also upgraded the ownership_model_eliminator test to
use semantic sil verification.
One issue that did come up though is that I was unable to use the new code in
all locations in the compiler. Specifically, there is one location in
SILGenPattern that uses argument unforwarding. I am going to need to undo
argument unforwarding in SILGenPattern in order to completely eliminate the old
code path.
This is in preparation for removing the +0 self hack.
This commit in more detail does the following:
1. It adds Formal Evaluation Scopes to certain places where the scopes were
missing. Specifically:
a. The SILGenLValue cases are places where we are invoking accessors. In each
one of these cases, we had a formal evaluation scope in the accessor
itself, but we did not have a scope that closed over the base access and
the accessor access. The base access is a formal evaluation in the sense
that just like with inout bases, we must create a new reference to the
base and re-destroy the base in a chain of accesses. This is to ensure
that we do not extend the lifetime of the base inappropriately.
b. The SILGenPoly case is a place where we have never properly placed a
Formal Evaluation Scope and have completely been relying on the +0 self
hack to make sure that archetype callees are properly destroyed
immediately after a +0 call.
2. It changes all of the places in SILGen that emit self to using formal access
cleanups instead of normal cleanups.
rdar://29791263
Eventually I want to move all of these emit* APIs to SILGenBuilder and make them
private details of SILGenBuilder. But that is a refactoring for another time.
rdar://29791263
Previously, we were emitting these cleanups at the end of the lexical scope
instead of at the end of the formal evaluation scope. This change ensures that
we always emit the cleanup immediately at the end of the formal evaluation
scope.
Previously in most cases we got away with this due to the +0 self
hack. Basically we would emit a get for a self parameter and then immediately
use that self parameter as a guaranteed parameter. Then the hack would insert
the destroy value forwarding the lexical scope level cleanup at the same time.
rdar://29791263
As per John, WritebackScope was always an unfortunate name. Generally these
scopes are meant for formal evaluations of inout parameters. The cases that I am
interested in generalizing them to be used for are borrows of the base of a
class that will then be used as an lvalue.
This also eliminates the out of line vector of lvalue writebacks.
rdar://29791263
SubstitutionList is going to be a more compact representation of
a SubstitutionMap, suitable for inline allocation inside another
object.
For now, it's just a typedef for ArrayRef<Substitution>.
There was only one place where we lowered AST types with a non-zero
uncurry level, in SILGenApply.cpp. Add a new overload of the
getSILFunctionType() method that takes an uncurry level. All the
other methods no longer have to thread it through.
Separate formal lowered types from SIL types.
The SIL type of an argument will depend on the SIL module's conventions.
The module conventions are determined by the SIL stage and LangOpts.
Almost NFC, but specialized manglings are broken incidentally as a result of
fixes to the way passes handle book-keeping of aruments. The mangler is fixed in
the subsequent commit.
Otherwise, NFC is intended, but quite possible do to rewriting the logic in many
places.
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
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>.
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>.
Before this commit all code relating to handling arguments in SILBasicBlock had
somewhere in the name BB. This is redundant given that the class's name is
already SILBasicBlock. This commit drops those names.
Some examples:
getBBArg() => getArgument()
BBArgList => ArgumentList
bbarg_begin() => args_begin()
Keep in mind that these are approximations that will not impact correctness
since in all cases I ensured that the SIL will be the same after the
OwnershipModelEliminator has run. The cases that I was unsure of I commented
with SEMANTIC ARC TODO. Once we have the verifier any confusion that may have
occurred here will be dealt with.
rdar://28685236
When AnyHashable was added, SILGen gained support for lowering
AnyHashableErasureExpr, however we forgot to also add support
for AnyHashable parameter and result conversions to
FunctionConversionExpr.
Fixes <https://bugs.swift.org/browse/SR-2603>.
Previously IRGen was using a heuristic to assign the argument number
to the $error variable that was not generally correct for optimizaed
code. This patch inserts a debug_value instruction in SILGen and thus
assigns the ArgNo together with all the other function arguments. This
is more robust and faster than than the old heuristic.
<rdar://problem/28748323>
Sema produces a weird mix of requirement and witness archetypes when
it builds witness substitutions. Instead of hacking around this in
SILGen, just build new archetypes, since we already have to use an
ArchetypeBuilder to get the correct generic signature on the interface
type.
Then, we just have to map the witnessSubs provided by Sema to use our
new archetypes.
This unblocks some work on generic inlining.
Fixes <rdar://problem/28765006>.
The behaviour of ilist has changed in LLVM. It is no longer permissible to
dereference the `end()` value. Add a check to ensure that we do not
accidentally dereference the iterator.
When emitting an existential erasure to Error from an archetype, use
the _getEmbeddedNSError() witness. If it produces an NSError, erase
that; otherwise, go through the normal erasure path.
Of course, make NSError and CFError implement _getEmbeddedNSError() so
this kicks in for the obvious cases as well as the more obscure ones.
Fixes the rest of SR-1562 / rdar://problem/26370984.
Previously, if a generic type had a stored property with
a generic type and an initializer expression, we would
emit the expression directly in the body of each designated
initializer.
This is a problem if the designated initializer is defined
within an extension (even in the same source file), because
extensions have a different set of generic parameters and
archetypes.
Also, we've had bugs in the past where emitting an
expression multiple times didn't work properly. While these
might currently all be fixed, this is a tricky case to test
and it would be best to avoid it.
Fix both problems by emitting the initializer expression
inside its own function at the SIL level, and call the
initializer function from each designated initializer.
I'm using the existing 'variable initializer' mangling for this;
it doesn't seem to be used for anything else right now.
Currently, the default memberwise initializer does not use
this, because the machinery for emitting it is somewhat
duplicated and separate from the initializer expressions in
user-defined constructors. I'll clean this up in an upcoming
patch.
Fixes <https://bugs.swift.org/browse/SR-488>.
String literal expressions, as well as the magic literals #file and
tuple value that is then fed into one or two call expressions. For
string literals, that tuple value was implicitly splatted, breaking
AST invariants.
Instead, keep string literals and these magic literals that produce a
string as a single expression node, but store the declarations that
will be used to transform the raw literal into the complete
literal. SILGen will form the appropriate calls. This representation
is far simpler---the AST no longer has a bunch of implicit nodes---and
doesn't break AST invariants.
If a `T?` is converted to `Any?` to pass to a `_Nullable id` interface in ObjC, avoid the intermediate conversion and bridge straight to AnyObject? too.
Till now there was no way in SIL to explicitly express a dependency of an instruction on any opened archetypes used by it. This was a cause of many errors and correctness issues. In many cases the code was moved around without taking into account these dependencies, which resulted in breaking the invariant that any uses of an opened archetype should be dominated by the definition of this archetype.
This patch does the following:
- Map opened archetypes to the instructions defining them, i.e. to open_existential instructions.
- Introduce a helper class SILOpenedArchetypesTracker for creating and maintaining such mappings.
- Introduce a helper class SILOpenedArchetypesState for providing a read-only API for looking up available opened archetypes.
- Each SIL instruction which uses an opened archetype as a type gets an additional opened archetype operand representing a dependency of the instruction on this archetype. These opened archetypes operands are an in-memory representation. They are not serialized. Instead, they are re-constructed when reading binary or textual SIL files.
- SILVerifier was extended to conduct more thorough checks related to the usage of opened archetypes.
Till now there was no way in SIL to explicitly express a dependency of an instruction on any opened archetypes used by it. This was a cause of many errors and correctness issues. In many cases the code was moved around without taking into account these dependencies, which resulted in breaking the invariant that any uses of an opened archetype should be dominated by the definition of this archetype.
This patch does the following:
- Map opened archetypes to the instructions defining them, i.e. to open_existential instructions.
- Introduce a helper class SILOpenedArchetypesTracker for creating and maintaining such mappings.
- Introduce a helper class SILOpenedArchetypesState for providing a read-only API for looking up available opened archetypes.
- Each SIL instruction which uses an opened archetype as a type gets an additional opened archetype operand representing a dependency of the instruction on this archetype. These opened archetypes operands are an in-memory representation. They are not serialized. Instead, they are re-constructed when reading binary or textual SIL files.
- SILVerifier was extended to conduct more thorough checks related to the usage of opened archetypes.
