When emitting an ignored expression, we try not perform a load of an lvalue if we can prove that loading has no observable side effects. Previously we based this on whether the components of the lvalue are physical, however some physical components (such as force unwrapping and key-paths) have side effects.
This commit introduces a new method to determine whether a component has side effects, and also adds an additional case to `emitIgnoredExpr` to avoid loading in cases where we have a force unwrap of an lvalue load (instead, if possible, try to emit the precondition using the lvalue address).
Stop creating ImplicitlyUnwrappedOptional<T> so that we can remove it
from the type system.
Enable the code that generates disjunctions for Optional<T> and
rewrites expressions based on the original declared type being 'T!'.
Most of the changes supporting this were previously merged to master,
but some things were difficult to merge to master without actually
removing IUOs from the type system:
- Dynamic member lookup and dynamic subscripting
- Changes to ensure the bridging peephole still works
Past commits have attempted to retain as much fidelity with how we
were printing things as possible. There are some cases where we still
are not printing things the same way:
- In diagnostics we will print '?' rather than '!'
- Some SourceKit and Code Completion output where we print a Type
rather than Decl.
Things like module printing via swift-ide-test attempt to print '!'
any place that we now have Optional types that were declared as IUOs.
There are some diagnostics regressions related to the fact that we can
no longer "look through" IUOs. For the same reason some output and
functionality changes in Code Completion. I have an idea of how we can
restore these, and have opened a bug to investigate doing so.
There are some small source compatibility breaks that result from
this change:
- Results of dynamic lookup that are themselves declared IUO can in
rare circumstances be inferred differently. This shows up in
test/ClangImporter/objc_parse.swift, where we have
var optStr = obj.nsstringProperty
Rather than inferring optStr to be 'String!?', we now infer this to
be 'String??', which is in line with the expectations of SE-0054.
The fact that we were only inferring the outermost IUO to be an
Optional in Swift 4 was a result of the incomplete implementation of
SE-0054 as opposed to a particular design. This should rarely cause
problems since in the common-case of actually using the property rather
than just assigning it to a value with inferred type, we will behave
the same way.
- Overloading functions with inout parameters strictly by a difference
in optionality (i.e. Optional<T> vs. ImplicitlyUnwrappedOptional<T>)
will result in an error rather than the diagnostic that was added
in Swift 4.1.
- Any place where '!' was being used where it wasn't supposed to be
allowed by SE-0054 will now treat the '!' as if it were '?'.
Swift 4.1 generates warnings for these saying that putting '!'
in that location is deprecated. These locations include for example
typealiases or any place where '!' is nested in another type like
`Int!?` or `[Int!]`.
This commit effectively means ImplicitlyUnwrappedOptional<T> is no
longer part of the type system, although I haven't actually removed
all of the code dealing with it yet.
ImplicitlyUnwrappedOptional<T> is is dead, long live implicitly
unwrapped Optional<T>!
Resolves rdar://problem/33272674.
This has three principal advantages:
- It gives some additional type-safety when working
with known accessors.
- It makes it significantly easier to test whether a declaration
is an accessor and encourages the use of a common idiom.
- It saves a small amount of memory in both FuncDecl and its
serialized form.
This patch moves the ownership of profiling state from SILGenProfiling
to SILFunction, where it always belonged. Similarly, it moves ownership
of the profile reader from SILGenModule to SILModule.
The refactor sets us up to fix a few outstanding code coverage bugs and
does away with sad hacks like ProfilerRAII. It also allows us to locally
guarantee that a profile counter increment actually corresponds to the
SILFunction at hand.
That local guarantee causes a bugfix to accidentally fall out of this
refactor: we now set up the profiling state for delayed functions
correctly. Previously, we would set up a ProfilerRAII for the delayed
function, but its counter increment would never be emitted :(. This fix
constitutes the only functional change in this patch -- the rest is NFC.
As a follow-up, I plan on removing some dead code in the profiling
logic and fixing a few naming inconsistencies. I've left that for later
to keep this patch simple.
This expression node is only used when applying the results of
expression type checking. It initially appears above the function
reference that returns an optional that needs to be unwrapped, and
then when dealing with function application we remove this and insert
a node to force-unwrap the result of the function application.
This patch moves the ownership of profiling state from SILGenProfiling
to SILFunction, where it always belonged. Similarly, it moves ownership
of the profile reader from SILGenModule to SILModule.
The refactor sets us up to fix a few outstanding code coverage bugs and
does away with sad hacks like ProfilerRAII. It also allows us to locally
guarantee that a profile counter increment actually corresponds to the
SILFunction at hand.
That local guarantee causes a bugfix to accidentally fall out of this
refactor: we now set up the profiling state for delayed functions
correctly. Previously, we would set up a ProfilerRAII for the delayed
function, but its counter increment would never be emitted :(. This fix
constitutes the only functional change in this patch -- the rest is NFC.
As a follow-up, I plan on removing some dead code in the profiling
logic and fixing a few naming inconsistencies. I've left that for later
to keep this patch simple.
This takes a series of ManagedValues and combines them together into 1 tuple. It
assumes that all non-trivial ManagedValues are all at +1 or all at +0. It leaves
the verification to the ownership verifier since this would immediately trigger
the ownership verifier when the instruction is created by the SILBuilder.
rdar://34222540
We can only do this for two reasons:
1. There is a code path that should have gone through the non-exclusively
borrowed self entrypoints, but they were not implemented.
2. We are trying to access self for an argument.
By copying the value, we preserve invariants around ownership and also make it
easy for DI to catch 2 and not blow up in the case of 1. It is better to error
in DI incorrectly, than to hit an unreachable (especially since in non-assert
builds, we don't trap at unreachables and just continue to the next function in
the text segment).
SR-5682
rdar://35402738
This rename makes since since:
1. This is SILGen specific functionality.
2. In the next commit I am going to be adding a SIL SavedInsertionPoint class. I
want to make sure the two can not be confused.
Support for @noescape SILFunctionTypes.
These are the underlying SIL changes necessary to implement the new
closure capture ABI.
Note: This includes a change to function name mangling that
primarily affects reabstraction thunks.
The new ABI will allow stack allocation of non-escaping closures as a
simple optimization.
The new ABI, and the stack allocation optimization, also require
closure context to be @guaranteed. That will be implemented as the
next step.
Many SIL passes pattern match partial_apply sequences. These all
needed to be fixed to handle the convert_function that SILGen now
emits. The conversion is now needed whenever a function declaration,
which has an escaping type, is passed into a @NoEscape argument.
In addition to supporting new SIL patterns, some optimizations like
inlining and SIL combine are now stronger which could perturb some
benchmark results.
These underlying SIL changes should be merged now to avoid conflicting
with other work. Minor benchmark discrepancies can be investigated as part of
the stack-allocation work.
* Add a noescape attribute to SILFunctionType.
And set this attribute correctly when lowering formal function types to SILFunctionTypes based on @escaping.
This will allow stack allocation of closures, and unblock a related ABI change.
* Flip the polarity on @noescape on SILFunctionType and clarify that
we don't default it.
* Emit withoutActuallyEscaping using a convert_function instruction.
It might be better to use a specialized instruction here, but I'll leave that up to Andy.
Andy: And I'll leave that to Arnold who is implementing SIL support for guaranteed ownership of thick function types.
* Fix SILGen and SIL Parsing.
* Fix the LoadableByAddress pass.
* Fix ClosureSpecializer.
* Fix performance inliner constant propagation.
* Fix the PartialApplyCombiner.
* Adjust SILFunctionType for thunks.
* Add mangling for @noescape/@escaping.
* Fix test cases for @noescape attribute, mangling, convert_function, etc.
* Fix exclusivity test cases.
* Fix AccessEnforcement.
* Fix SILCombine of convert_function -> apply.
* Fix ObjC bridging thunks.
* Various MandatoryInlining fixes.
* Fix SILCombine optimizeApplyOfConvertFunction.
* Fix more test cases after merging (again).
* Fix ClosureSpecializer. Hande convert_function cloning.
Be conservative when combining convert_function. Most of our code doesn't know
how to deal with function type mismatches yet.
* Fix MandatoryInlining.
Be conservative with function conversion. The inliner does not yet know how to
cast arguments or convert between throwing forms.
* Fix PartialApplyCombiner.
Specifically, load profiler counts corresponding to 'if' AST nodes and
attach them to the corresponding CondBranchInst's in SIL.
This is done using dirty tricks and isn't tested well enough :(.
- Hack the SIL printer to make profile count loading testable.
- Hack the profiler's counter map to store the indices of parent
region counters in entries for 'else stmts' and 'else exprs'.
It's too early to hack up the SILOptimizer to propagate profile counts.
It doesn't seem too hard, but I definitely don't know the code well
enough to write tests for it :(. So that's still a TODO.
Next, we should be able to produce some acutual llvm branch_weight
metadata!
- Remove dead `if !genericEnv` checks
- Do conformance checks for subscript indexes `InExpression`
- Use `GenericEnvironment::mapTypeOutOfContext` static method instead of null checking everywhere
The base mutability of storage is part of the signature, so be sure
to compute that during validation. Also, serialize it as part of
the storage declaration, and fix some places that synthesize
declarations to set it correctly.
This eliminates a bunch of complexity from delegating init self since now we
have a clear bifurcation, before the begin of the super.init call, you use the
normal cleanup machinery, but once you have begun the super.init call, you use
the lvalue/formal evaluation machinery.
rdar://31521023
The specific exposed problem had to do with my using the same emission routine
for both lvalues using delegating init self (where we want formal accesses) and
for routines that wanted normal access to self. By splitting them the issue is
resolved.
As a benefit, I added a small peephole that I needed to add for my own purposes
(i.e. to maintain invariants), but that also incidentally improve codegen in
other places!
rdar://31521023
Use the ManagedValue forms of the SILInstruction constructors
where possible. This ensures that after emitting an instruction
such as an upcast, we rewrite the value's cleanup to destroy
the new value, and not the old value. This is important because
the ownership verifier asserts that instructions dominated by
a destroy cannot use the destroyed value.
Should be NFC, since the ownership verifier is off by default
for now.
A protocol extension initializer creates a new instance of the
static type of Self at the call site.
However a convenience initializer in a class is expected to
initialize an instance of the dynamic type of the 'self' value,
because convenience initializers can be inherited by subclasses.
This means that when a convenience initializer delegates to a
protocol extension initializer, we have to substitute the
'Self' type in the protocol extension generic signature with
the DynamicSelfType, and not the static type.
Since the substitution is formed from the type of the 'self'
parameter in the class convenience initializer, the solution is
to change the type of 'self' in a class convenience initializer
to DynamicSelfType, just like we do for methods that return
'Self'.
This fixes cases where we allowed code to type check that
should not type check (if the protocol extension initializer
has 'Self' in contravariant position, and we pass in an
instance of the static type).
It also fixes a miscompile with valid code -- if the protocol
extension initializer was implemented by calling 'Self()',
it would again use the static type and not the dynamic type.
Note that the SILGen change is necessary because Sema now creates
CovariantReturnExprs that convert a static class type to
DynamicSelfType, but the latter lowers to the former at the
SIL level, so we have to peephole away unnecessary unchecked_ref_cast
instructions in this case.
Because this change breaks source compatibility, it is guarded
by a '-swift-version 5' check.
