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.
This is useful to discover when a specific cleanup is being eliminated while
debugging. The implementation is compiled out when assertions are disabled.
rdar://29791263
In cases where a default value is used for a parameter with generic
type, the argument list might be empty. In that case, we don't need
to emit any arguments!
Storing this separately is unnecessary since we already
serialize the enum element's interface type. Also, this
eliminates one of the few remaining cases where we serialize
archetypes during AST serialization.
[NFC] Add -enable-sil-opaque-values frontend option.
This will be used to change the SIL-level calling convention for opaque values,
such as generics and resilient structs, to pass-by-value. Under this flag,
opaque values have SSA lifetimes, managed by copy_value and destroy_value.
This will make it easier to optimize copies and verify ownership.
* [SILGen] type lowering support for opaque values.
Add OpaqueValueTypeLowering.
Under EnableSILOpaqueValues, lower address-only types as opaque values.
* [SIL] Fix ValueOwnershipKind to support opaque SIL values.
* Test case: SILGen opaque value support for Parameter/ResultConvention.
* [SILGen] opaque value support for function arguments.
* Future Test case: SILGen opaque value specialDest arguments.
* Future Test case: SILGen opaque values: emitOpenExistential.
* Test case: SIL parsing support for EnableSILOpaqueValues.
* SILGen opaque values: prepareArchetypeCallee.
* [SIL Verify] allow copy_value for EnableSILOpaqueValues.
* Test cast: SIL serializer support for opaque values.
* Add a static_assert for ParameterConvention layout.
* Test case: Mandatory SILOpt support for EnableSILOpaqueValues.
* Test case: SILOpt support for EnableSILOpaqueValues.
* SILGen opaque values: TypeLowering emitCopyValue.
* SILBuilder createLoad. Allow loading opaque values.
* SIL Verifier. Allow loading and storing opaque values.
* SILGen emitSemanticStore support for opaque values.
* Test case for SILGen emitSemanticStore.
* Test case for SIL mandatory support for inout assignment.
* Fix SILGen opaque values test case after rebasing.
Formal types are defined by the language's type system. SIL types are
lowered. They are no longer part of that type system.
The important distinction here is between the SIL storage type and the SIL value
type. To make this distinction clear, I refer to the SILFunctionTypes "formal"
conventions. These conventions dictate the SIL storage type but *not* the SIL
value type. I call them "formal" conventions because they are an immutable
characteristic of the function's type and made explicit via qualifiers on the
function type's parameters and results. This is in contrast to to SIL
conventions which depend on the SIL stage, and in the short term whether the
opaque values flag is enabled.
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.
Most of this involved sprinkling ValueOwnershipKind::Owned in many places. In
some of these places, I am sure I was too cavalier and I expect some of them to
be trivial. The verifier will help me to track those down.
On the other hand, I do expect there to be some places where we are willing to
accept guaranteed+trivial or owned+trivial. In those cases, I am going to
provide an aggregate ValueOwnershipKind that will then tell SILArgument that it
should disambiguate using the type. This will eliminate the ackwardness from
such code.
I am going to use a verifier to fix such cases.
This commit also begins the serialization of ValueOwnershipKind of arguments,
but does not implement parsing of value ownership kinds. That and undef are the
last places that we still use ValueOwnershipKind::Any.
rdar://29791263
This is dead code and can be re-added if it is needed. Right now though there
really isnt a ValueOwnershipKind that corresponds to deallocating and I do not
want to add a new ValueOwnershipKind for dead code.
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.
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
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.
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.
The RValue(ArrayRef<ManagedValue>, CanType) constructor was intended as a semi-private interface for building an RValue from a pre-exploded array of elements, but was (understandably) widely being misused as a general ManagedValue-to-RValue constructor, causing crashes when working with tuples in various contexts where RValue's methods expected them to be exploded. Make the constructor private and update most improper uses of it to use the exploding RValue constructor, or to use a new `RValue::withPreExplodedElements` static method that more explicitly communicates the intent of the constructor. Fixes rdar://problem/29500731.
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
This ensures that ownership is properly propagated forward through the use-def
graph.
This was the work that was stymied by issues relating to SILBuilder performing
local ARC dataflow. I ripped out that local dataflow in 6f4e2ab and added a
cheap ARC guaranteed dataflow pass that performs the same optimization.
Also in the process of doing this work, I found that there were many SILGen
tests that were either pattern matching in the wrong functions or had wrong
CHECK lines (for instance CHECK_NEXT). I fixed all of these issues and also
expanded many of the tests so that they verify ownership. The only work I left
for a future PR is that there are certain places in tests where we are using the
projection from an original value, instead of a copy. I marked those with a
message SEMANTIC ARC TODO so that they are easy to find.
rdar://28685236
The `emitNativeToBridgedValue` code is not well-factored to pass down the formal type of the value being bridged, which is necessary to build a generic call to _bridgeAnythingToObjectiveC in the fallback case. To work around this issue, disable the expression peephole when the type is not a valid lowered SIL type as is. Short-term fix for rdar://problem/28318984.
This allows for slightly better codegen for nested functions that refer to other nested functions that don't transitively capture any local state, but more importantly, allows methods of local types to work while still referring to nested functions that don't capture local state, fixing rdar://problem/28015090.
