This attribute can be attached to a noncopyable struct to specify that its
storage is raw, meaning the type definition is (with some limitations)
able to do as it pleases with the storage. This provides a basis for
implementing types for things like atomics, locks, and data structures
that use inline storage to store conditionally-initialized values.
The example in `test/Prototypes/UnfairLock.swift` demonstrates the use
of a raw layout type to wrap Darwin's `os_unfair_lock` APIs, allowing
a lock value to be stored inside of classes or other types without
needing a separate allocation, and using the borrow model to enforce
safe access to lock-guarded storage.
As with the initial value of a property that is converted from a stored
property to a computed property by an accessor macro, remove
didSet/willSet. It is the macro's responsibility to incorporate their
code or diagnose them.
Fixes rdar://111101833.
Address a few related issues that affect local types and opaque result types within macros:
* Don't add local types or opaque types encountered while parsing the
arguments of a freestanding macro to the global list. When we do add
them, make sure we're adding them to the outermost source file so
they'll get seen later. This avoids trying to generate code for these
types, because they aren't supposed to be part of the program. Note
that a similar problem remains for arguments to attached macros, which
will need to be addressed with a more significant refactoring.
* When determining whether opaque types should be substituted within a
resilience domain, check the outermost source files rather than the exact
source file, otherwise we will end up with a mismatch in
argument-passing conventions.
* When delaying the type checking of functions that occur as part of a
macro expansion, make sure we record them in the outermost Swift source
file. Otherwise, we won't come back to them.
There is a common theme here of using AST state on the source file in
a manner that isn't ideal, and starts to break down with macros. In
these cases, we're relying on side effects from earlier phases
(parsing and type checking) to inform later phases, rather than
properly expressing the dependencies through requests.
Fixes rdar://110674997&110713264.
Attribute @_silgen_name is today only allowed to be used on functions, this change allows usage on globals as well. The motivation for that is to be able to "forward declare" globals just like it's today possible to do with functions (for the cases where it's not practical or convenient to use a bridging header).
Separately, this change also adds a @_silgen_name(raw: ...) syntax, which simply avoids mangling the name (by using the \01 name prefix that LLVM uses). The motivation for that is to be able to reference the "magic Darwin linker symbols" that can be used to look up section bounds (in the current dylib/module) -- those symbols don't use the underscore prefix in their mangled names.
Reformatting everything now that we have `llvm` namespaces. I've
separated this from the main commit to help manage merge-conflicts and
for making it a bit easier to read the mega-patch.
This is phase-1 of switching from llvm::Optional to std::optional in the
next rebranch. llvm::Optional was removed from upstream LLVM, so we need
to migrate off rather soon. On Darwin, std::optional, and llvm::Optional
have the same layout, so we don't need to be as concerned about ABI
beyond the name mangling. `llvm::Optional` is only returned from one
function in
```
getStandardTypeSubst(StringRef TypeName,
bool allowConcurrencyManglings);
```
It's the return value, so it should not impact the mangling of the
function, and the layout is the same as `std::optional`, so it should be
mostly okay. This function doesn't appear to have users, and the ABI was
already broken 2 years ago for concurrency and no one seemed to notice
so this should be "okay".
I'm doing the migration incrementally so that folks working on main can
cherry-pick back to the release/5.9 branch. Once 5.9 is done and locked
away, then we can go through and finish the replacement. Since `None`
and `Optional` show up in contexts where they are not `llvm::None` and
`llvm::Optional`, I'm preparing the work now by going through and
removing the namespace unwrapping and making the `llvm` namespace
explicit. This should make it fairly mechanical to go through and
replace llvm::Optional with std::optional, and llvm::None with
std::nullopt. It's also a change that can be brought onto the
release/5.9 with minimal impact. This should be an NFC change.
The parser is currently responsible for adding local type declarations
to a `SourceFile`, which IR generation later queries. However, IRGen
never sees the source files associated with macro expansion buffers,
so local types introduced there don't get recorded.
In time, this approach of using the parser to record semantic
information should be replaced with something more "pull" oriented.
For now, however, record local type declarations in the outermost
enclosing source file... so we see the ones produced by macro
expansions, too.
Fixes rdar://109370309.
'MacroExpansionDecl' and 'MacroExpansionExpr' have many common methods.
Introduce a common base class 'FreestandingMacroExpansion' that holds
'MacroExpansionInfo'.
Factor out common expansion logic to 'evaluateFreestandingMacro'
function that resembles 'evaluateAttachedMacro'.
Direct lookup relied in primary file checking to have filled in the
protocol type stored in the ImplementsAttr. This was already wrong
with multi-file test cases in non-WMO mode, and crashed in the
ASTPrinter if printing a declaration in a non-primary file.
I don't have a standalone test case that is independent of my
upcoming ASTPrinter changes, but this is a nice cleanup regardless.
API development sometimes requires a redesign while supporting early
adopters. Currently this is done by adding @_spi(name) to the API but
that requires adding the attribute in import statements as well, causing
manual overhead of adding and then removing when the redesign is done.
This PR introduces a special spi group name '_' and allows an implicit
spi import of a module containing API attributed with '@_spi(_)'
Resolves rdar://109797632
* Add @_used and @_section attributes for global variables and top-level functions
This adds:
- @_used attribute that flags as a global variable or a top-level function as
"do not dead-strip" via llvm.used, roughly the equivalent of
__attribute__((used)) in C/C++.
- @_section("...") attribute that places a global variable or a top-level
function into a section with that name, roughly the equivalent of
__attribute__((section("..."))) in C/C++.
Avoid parsing the syntax tree up-front, and instead
only parse it when required, which happens when either:
1. ASTGen parsing is enabled (currently disabled
by default)
2. Round trip checking is enabled for a primary
file (enabled by default in a debug build,
except when dep scanning or doing an IDE
operation)
3. We need to evaluate a macro in that file
This change therefore means that we now no longer
need to parse the syntax tree for secondary files
by default unless we specifically need to evaluate
a macro in them (e.g if we need to lookup a member
on a decl with an attached macro). And the same
for primaries in release builds.
rdar://109283847
* Unify macro expansion parsing logic between MacroExpansionExpr and
MacroExpansionDecl
* Diagnose whitespace between '#' and the macro name
* Diagnose keyword as a macro name
* Parse `#<identifier>` attribute list as a `MacroExpansionDecl`
regardless of the position
* Diagnose whitespaces between `#` and the macro name.
* Correctly attach attributes to `MacroExpansionDecl`
* Fix `OrigDeclAttributes` to handle modifiers (use `getLocation()`
instead of `AtLoc`.)
Type checking is a TODO
rdar://107386648
