(containing just an uncond branch) when a shared block isn't actually shared.
This is a revised version of r26676 that makes sure to emit the cleanups for a
case pattern as soon as possible. Extending the lifetime of the case value
across the body of the switch caused extra copies of COW types.
Swift SVN r26685
This patch introduces a new kind of pattern for matching bool literals, i.e. true and false. Essentially, it is very similar to a pattern for matching enum elements, but simpler. Most of the code is just a boiler plate code copy/pasted from the code for enum element patterns. The only different thing is the emitBoolDispatch function, which emits a SIL code for matching bools.
With this patch, we don't get any false non-exhaustive switch diagnostics for switches on bools anymore. And we have a lot of radars complaining about it. For example rdar://16514545 and rdar://20130240.
Note, that this patch fixes the non-exhaustive switch diagnostics without changing the internal representation of bools. Implementing bool as an enum would have the same effect when it comes to these diagnostics and we would get this diagnostics fix for free, i.e. without any code committed here. But implementing bools-as-enums is an ongoing work and I'm investigating its performance implications. If we become confident that bool-as-enum does not have a negative impact on performance and decide to merge it, then we can revert this patch as it would not be necessary anymore. But if we decide to skip the enum-as-bool approach to its performance issues, then we would have at least fixed the false non-exhaustive diagnostics for bools by means of this patch.
Swift SVN r26650
Remove the semantic restrictions that prohibited extensions of
protocol types, and start making some systematic changes so that
protocol extensions start to make sense:
- Replace a lot of occurrences of isa<ProtocolDecl> and
dyn_cast<ProtocolDecl> on DeclContexts to use the new
DeclContext::isProtocolOrProtocolExtensionContext(), where we want
that behavior to apply equally to protocols and protocol extensions.
- Eliminate ProtocolDecl::getSelf() in favor of
DeclContext::getProtocolSelf(), which produces the appropriate
generic type parameter for the 'Self' of a protocol or protocol
extension. Update all of the callers of ProtocolDecl::getSelf()
appropriately.
- Update extension validation to appropriately form generic
parameter lists for protocol extensions.
- Methods in protocol extensions always use the witnesscc calling
convention.
At this point, we can type check and SILGen very basic definitions of
protocol extensions with methods that can call protocol requirements,
generic free functions, and other methods within the same protocol
extension.
Regresses four compiler crashers but improves three compiler
crashers... we'll call that "progress"; the four regressions all hit
the same assertion in the constraint system that will likely be
addressed as protocol extensions starts working.
Swift SVN r26579
We no longer need or use it since we can always refer to the same bit on
the applied function when deciding whether to inline during mandatory
inlining.
Resolves rdar://problem/19478366.
Swift SVN r26534
The string version of r26479. There's a lot of backstory and justification
there, so just read that commit message again. The one addition for String
is that global NSString constants are loaded as String as well, so that
also has to go through the bridging code even though there's no function
call involved.
Finishes rdar://problem/19734621.
Swift SVN r26510
...and similar for NSDictionary and NSSet.
For APIs that don't have a reason to distinguish "empty" and "absent" cases,
we encourage standardizing on "empty" and marking the result as non-optional
(or in Objective-C, __nonnull). However, there are system APIs whose
implementations currently do return nil rather than an empty collection
instance. In these cases, we recommend /changing/ the API to return the
appropriate "empty" value instead.
However, this can cause problems for backwards-deployment: while the API is
truly non-optional on system vN, a program may encounter a nil return value
if run on system vN-1. Objective-C can generally deal with this (especially
if the only thing you do is ask for the count or try to iterate over the
collection) but Swift can't. Therefore, we've decided to "play nice" and
accept nil return values for the collection types (NSArray, NSDictionary,
and NSSet) and implicitly treat them as "empty" values if they are the
result of an imported function or method.
Note that the current implementation has a hole regarding subscript getters,
since we still make an AST-level thunk for these in the Clang importer.
We can probably get rid of those these days, but I didn't want to touch
them at this point. It seems unlikely that there will be a subscript that
(a) is for a collection type, and (b) mistakenly returned nil in the past
rather than an empty collection.
There's another hole where an ObjC client calls one of these mistakenly-nil-
returning methods and then immediately hands the result off by calling a
Swift method. However, we have to draw the line somewhere.
(We're actually going to do this for strings as well; coming soon.)
rdar://problem/19734621
Swift SVN r26479
Currently a no-op, but effective access for entities within the current
module will soon need to take testability into account. This declaration:
internal func foo() {}
has a formal access of 'internal', but an effective access of 'public' if
we're in a testable mode.
Part of rdar://problem/17732115 (testability)
Swift SVN r26472
This change permits SILGen to make smarter decisions about
block placement by keeping related blocks together instead
of always inserting to the end to the function. The
flipside is that SILGen needs to be somewhat careful to
create blocks in the right order. Counter-intuitively,
that order is the reverse of the order in which the blocks
should be laid out, since blocks created later will be
inserted before blocks created earlier. Note, however,
that this produces the right results for recursive
emission.
To that end, adjust a couple of places in SILGen to
create blocks in properly nested order.
All of the block-order differences in the tests seem
to be desirable; several of them even had confused
comments wondering how on earth a block got injected
where it did.
Also, fix the implementation of SILBuilder::moveBlockTo,
and fix a latent bug in epilogue emission where epilogBB
was erased from its parent (deleting it) and then
queried multiple times (!).
Swift SVN r26428
This patch also introduces some SILGen infrastructure for
dividing the function into "ordinary" and "postmatter"
sections, with error-handling-like stuff going into the
final section. Currently, this is largely undermined by
SILBuilder, but I'm going to fix that in a follow-up.
Swift SVN r26422
Getting the protocols of an arbitrary type doesn't make sense, so start phasing this out by introducing specialized entry points that do make sense:
- get the inherited protocols of a ProtocolDecl
- get the conforming protocols for an associated type or generic
type parameter
- (already present) ask for the protocols to which a nominal type conforms
Swift SVN r26411
This means:
1. In_Guaranteed when preparing accessor base args is like @in not
@inout. This is because @in_guaranteed parameters are immutable. We
were not miscompiling since we were not inserting cleanups for these
parameters. Now with 2, we perform the copy so we have the immutable
property and then destroy_addr the result after the call.
2. If we have a guaranteed parameter, we put the destroy value right
after the call instead of at the end of expression.
The reason 2 is necessary is that if we destroy the value at the end of
scope situations like the following cause COW to fail:
struct Foo {
let object: AnyObject
var rawObject: Builtin.RawPointer {
return Builtin.bridgeToRawPointer(object) // Psuedoname of builtin.
}
mutating func isUnique() -> Bool {
return isUnique(rawObject)
}
}
What happens is that because Foo.isUnique is mutating, Foo is passed in
@inout. Since @inout is a guarantee related to memory, SILGen has to
increment the refcount of self to guarantee self's lifetime. Before this
patch we would have (in pseudo-sil).
%self = load %ptr_self
retain_value %self
%0 = getRawObject() // guaranteed call.
%result = isUnique(%0)
release_value %self
This causes the COW check to always fail. There is no reason to extend
the lifetime of %self so far, guaranteed only means that the object's
lifetime is guaranteed over the call in question. So now instead, we
release after the call.
<rdar://problem/20094305>
<rdar://problem/20234910>
Swift SVN r26351
Replace the loop over all known protocols with a query into the
actual conformance lookup table, which more properly deals with
out-of-order conformance queries, inheritance of protocol
conformances, and conformance queries in multi-file situtations.
The SILGen test change is because we're no longer emitting redundant
conformances, while the slight diagnostic regression in
circular-inheritance cases is because we handle circular inheritance
very poorly throughout the compiler.
While not the end, this is a major step toward finishing
rdar://problem/18448811.
Swift SVN r26299
Leave a cleanup to deinit the container after the uniquely-referenced opaque value is taken out of it. While we're here, stub out support for boxed existentials (though we can't test it since _ErrorType doesn't have any Self-returning methods, and we currently only produce OpenExistentialExprs in the AST for method calls involving covariant Self or metatypes).
Swift SVN r26284
Previously, a multi-pattern var/let decl like:
var x = 4, y = 17
would produce two pattern binding decls (one for x=4 one for y=17). This is convenient
in some ways, but is bad for source reproducibility from the ASTs (see, e.g. the improvements
in test/IDE/structure.swift and test/decl/inherit/initializer.swift).
The hardest part of this change was to get parseDeclVar to set up the AST in a way
compatible with our existing assumptions. I ended up with an approach that forms PBDs in
more erroneous cases than before. One downside of this is that we now produce a spurious
"type annotation missing in pattern"
diagnostic in some cases. I'll take care of that in a follow-on patch.
Swift SVN r26224
The deallocating parameter convention is a new convention put on a
non-trivial parameter if the caller function guarantees to the callee
that the parameter has the deallocating bit set in its object header.
This means that retains and releases do not need to be emitted on these
parameters even though they are non-trivial. This helps to solve a bug
in +0 self and makes it trivial for the optimizer to perform
optimizations based on this property.
It is not emitted yet by SILGen and will only be put on the self
argument of Deallocator functions.
Swift SVN r26179
- Rename getParentPattern() -> getParentPatternBinding(), since
it returns the pattern binding, not the pattern.
- Introduce new getParentPattern()/getParentInitializer() methods,
covering the most common uses of getParentPatternBinding().
NFC.
Swift SVN r26175
This changes 'if let' conditions to take general refutable patterns, instead of
taking a irrefutable pattern and implicitly matching against an optional.
Where before you might have written:
if let x = foo() {
you now need to write:
if let x? = foo() {
The upshot of this is that you can write anything in an 'if let' that you can
write in a 'case let' in a switch statement, which is pretty general.
To aid with migration, this special cases certain really common patterns like
the above (and any other irrefutable cases, like "if let (a,b) = foo()", and
tells you where to insert the ?. It also special cases type annotations like
"if let x : AnyObject = " since they are no longer allowed.
For transitional purposes, I have intentionally downgraded the most common
diagnostic into a warning instead of an error. This means that you'll get:
t.swift:26:10: warning: condition requires a refutable pattern match; did you mean to match an optional?
if let a = f() {
^
?
I think this is important to stage in, because this is a pretty significant
source breaking change and not everyone internally may want to deal with it
at the same time. I filed 20166013 to remember to upgrade this to an error.
In addition to being a nice user feature, this is a nice cleanup of the guts
of the compiler, since it eliminates the "isConditional()" bit from
PatternBindingDecl, along with the special case logic in the compiler to handle
it (which variously added and removed Optional around these things).
Swift SVN r26150
in terms of the pattern binding/emission facilities that are currently
used for switches. They are more general (handling all patterns,
not hacked up just for optionals).
This leads to us producing better code for if/let bindings, because we
don't alloc_stack a temporary and deal with memory for non-address-only
types (e.g. the common case of an optional pointer). Instead, the code
emits a select_enum{_addr} on the value.
While this changes the generated code in the compiler, there is no exposed
behavioral change to the developer.
Swift SVN r26142
John points out that we would still need to evaluate default arguments in an ignored context, and these cases aren't important to fixing the bug.
Swift SVN r26108
