radar rdar://problem/28434323
SILGen has no reason to insert shadow copies for inout parameters any more. They cannot be captured. We still emit these copies. Sometimes deshadowing removes them, but sometimes it does not.
In this PR we just avoid emitting the copies and remove the deshadowing pass.
This PR chery-picked some of @dduan work and built on top of it.
This flips the switch to have @noescape be the default semantics for
function types in argument positions, for everything except property
setters. Property setters are naturally escaping, so they keep their
escaping-by-default behavior.
Adds contentual printing, and updates the test cases.
There is some further (non-source-breaking) work to be done for
SE-0103:
- We need the withoutActuallyEscaping function
- Improve diagnostics and QoI to at least @noescape's standards
- Deprecate / drop @noescape, right now we allow it
- Update internal code completion printing to be contextual
- Add more tests to explore tricky corner cases
- Small regressions in fixits in attr/attr_availability.swift
Similarly to how we've always handled parameter types, we
now recursively expand tuples in result types and separately
determine a result convention for each result.
The most important code-generation change here is that
indirect results are now returned separately from each
other and from any direct results. It is generally far
better, when receiving an indirect result, to receive it
as an independent result; the caller is much more likely
to be able to directly receive the result in the address
they want to initialize, rather than having to receive it
in temporary memory and then copy parts of it into the
target.
The most important conceptual change here that clients and
producers of SIL must be aware of is the new distinction
between a SILFunctionType's *parameters* and its *argument
list*. The former is just the formal parameters, derived
purely from the parameter types of the original function;
indirect results are no longer in this list. The latter
includes the indirect result arguments; as always, all
the indirect results strictly precede the parameters.
Apply instructions and entry block arguments follow the
argument list, not the parameter list.
A relatively minor change is that there can now be multiple
direct results, each with its own result convention.
This is a minor change because I've chosen to leave
return instructions as taking a single operand and
apply instructions as producing a single result; when
the type describes multiple results, they are implicitly
bound up in a tuple. It might make sense to split these
up and allow e.g. return instructions to take a list
of operands; however, it's not clear what to do on the
caller side, and this would be a major change that can
be separated out from this already over-large patch.
Unsurprisingly, the most invasive changes here are in
SILGen; this requires substantial reworking of both call
emission and reabstraction. It also proved important
to switch several SILGen operations over to work with
RValue instead of ManagedValue, since otherwise they
would be forced to spuriously "implode" buffers.
And use project_box to get to the address value.
SILGen now generates a project_box for each alloc_box.
And IRGen re-uses the address value from the alloc_box if the operand of project_box is an alloc_box.
This lets the generated code be the same as before.
Other than that most changes of this (quite large) commit are straightforward.
'Ss' appears in manglings tens of thousands of times in the standard library and is also incredibly frequent in other modules. This alone is enough to shrink the standard library by 59KB.
Swift SVN r32409
The rule changes are as follows:
* All functions (introduced with the 'func' keyword) have argument
labels for arguments beyond the first, by default. Methods are no
longer special in this regard.
* The presence of a default argument no longer implies an argument
label.
The actual changes to the parser and printer are fairly simple; the
rest of the noise is updating the standard library, overlays, tests,
etc.
With the standard library, this change is intended to be API neutral:
I've added/removed #'s and _'s as appropriate to keep the user
interface the same. If we want to separately consider using argument
labels for more free functions now that the defaults in the language
have shifted, we can tackle that separately.
Fixes rdar://problem/17218256.
Swift SVN r27704
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 problem here was that the _preconditionImplicitlyUnwrappedOptionalHasValue
compiler intrinsic was taking the optional/IUO argument as inout as a performance
optimization, but DI would reject it (in narrow cases, in inits) because the inout
argument looks like a mutation.
We could rework this to take it as an @in argument or something, but it is better
to just define this problem away: the precondition doesn't actually care about the
optional, it is just testing its presence, which SILGen does all the time. Have
SILGen open code the switch_enum and just have the stdlib provide a simpler
_diagnoseUnexpectedNilOptional() to produce the error message.
This avoids the problem completely and produces slightly better -O0 codegen.
Swift SVN r25254
Most tests were using %swift or similar substitutions, which did not
include the target triple and SDK. The driver was defaulting to the
host OS. Thus, we could not run the tests when the standard library was
not built for OS X.
Swift SVN r24504
Previously, we were binding optional l-values only when
performing an access. This meant that other evaluations
emitted before the formal access were not being
short-circuited, even if the language rules said they
should be. For example, consider this code::
var array : [Int]? = ...
array?[foo()] = bar()
Neither foo nor bar should be called if the array is
actually nil, because those calls are sequenced after
the optional-chaining operator ?.
The way that we currently do this is to project out
the optional address during formal evaluation. This
means that there's a formal access to that storage
beginning with the formal evaluation of the l-value
and lasting until the operation is complete. That's
a little controversial, because it means that other
formal accesses during that time to the optional
storage will have unspecified behavior according to
the rules I laid out in the accessors proposal; we
should talk about it and make a decision about
whether we're okay with this behavior. But for now,
it's important to at least get the right short-circuiting
behavior from ?.
Swift SVN r23608
Now the SILLinkage for functions and global variables is according to the swift visibility (private, internal or public).
In addition, the fact whether a function or global variable is considered as fragile, is kept in a separate flag at SIL level.
Previously the linkage was used for this (e.g. no inlining of less visible functions to more visible functions). But it had no effect,
because everything was public anyway.
For now this isFragile-flag is set for public transparent functions and for everything if a module is compiled with -sil-serialize-all,
i.e. for the stdlib.
For details see <rdar://problem/18201785> Set SILLinkage correctly and better handling of fragile functions.
The benefits of this change are:
*) Enable to eliminate unused private and internal functions
*) It should be possible now to use private in the stdlib
*) The symbol linkage is as one would expect (previously almost all symbols were public).
More details:
Specializations from fragile functions (e.g. from the stdlib) now get linkonce_odr,default
linkage instead of linkonce_odr,hidden, i.e. they have public visibility.
The reason is: if such a function is called from another fragile function (in the same module),
then it has to be visible from a third module, in case the fragile caller is inlined but not
the specialized function.
I had to update lots of test files, because many CHECK-LABEL lines include the linkage, which has changed.
The -sil-serialize-all option is now handled at SILGen and not at the Serializer.
This means that test files in sil format which are compiled with -sil-serialize-all
must have the [fragile] attribute set for all functions and globals.
The -disable-access-control option doesn't help anymore if the accessed module is not compiled
with -sil-serialize-all, because the linker will complain about unresolved symbols.
A final note: I tried to consider all the implications of this change, but it's not a low-risk change.
If you have any comments, please let me know.
Swift SVN r22215
Factor out the code for emitting the "bind" branching logic, and share it to implement an LValueComponent for optional binds, which makes optional assignments work.
Swift SVN r20614
Add a set of _preconditionOptionalHasValue intrinsics that merely test that an optional has a case. Emit an lvalue ForceValueExpr as a physical lvalue, first asserting the precondition then projecting out the Some payload.
Swift SVN r20188
