Introduce co- and contra-variance for Objective-C type parameters,
which allows us to express that (for example) an NSArray is covariant
in its type parameter. This means that NSArray<NSMutableString *> * is
a subtype of NSArray<NSString *> *, which is expected of the immutable
Foundation collections.
Type parameters can be annotated with __covariant or __contravariant
to make them co- or contra-variant, respectively. This feature can be
detected by __has_feature(objc_generics_variance). Implements
rdar://problem/20217490.
llvm-svn: 241549
When messaging a method that was defined in an Objective-C class (or
category or extension thereof) that has type parameters, substitute
the type arguments for those type parameters. Similarly, substitute
into property accesses, instance variables, and other references.
This includes general infrastructure for substituting the type
arguments associated with an ObjCObject(Pointer)Type into a type
referenced within a particular context, handling all of the
substitutions required to deal with (e.g.) inheritance involving
parameterized classes. In cases where no type arguments are available
(e.g., because we're messaging via some unspecialized type, id, etc.),
we substitute in the type bounds for the type parameters instead.
Example:
@interface NSSet<T : id<NSCopying>> : NSObject <NSCopying>
- (T)firstObject;
@end
void f(NSSet<NSString *> *stringSet, NSSet *anySet) {
[stringSet firstObject]; // produces NSString*
[anySet firstObject]; // produces id<NSCopying> (the bound)
}
When substituting for the type parameters given an unspecialized
context (i.e., no specific type arguments were given), substituting
the type bounds unconditionally produces type signatures that are too
strong compared to the pre-generics signatures. Instead, use the
following rule:
- In covariant positions, such as method return types, replace type
parameters with “id” or “Class” (the latter only when the type
parameter bound is “Class” or qualified class, e.g,
“Class<NSCopying>”)
- In other positions (e.g., parameter types), replace type
parameters with their type bounds.
- When a specialized Objective-C object or object pointer type
contains a type parameter in its type arguments (e.g.,
NSArray<T>*, but not NSArray<NSString *> *), replace the entire
object/object pointer type with its unspecialized version (e.g.,
NSArray *).
llvm-svn: 241543
Objective-C type arguments can be provided in angle brackets following
an Objective-C interface type. Syntactically, this is the same
position as one would provide protocol qualifiers (e.g.,
id<NSCopying>), so parse both together and let Sema sort out the
ambiguous cases. This applies both when parsing types and when parsing
the superclass of an Objective-C class, which can now be a specialized
type (e.g., NSMutableArray<T> inherits from NSArray<T>).
Check Objective-C type arguments against the type parameters of the
corresponding class. Verify the length of the type argument list and
that each type argument satisfies the corresponding bound.
Specializations of parameterized Objective-C classes are represented
in the type system as distinct types. Both specialized types (e.g.,
NSArray<NSString *> *) and unspecialized types (NSArray *) are
represented, separately.
llvm-svn: 241542
Produce type parameter declarations for Objective-C type parameters,
and attach lists of type parameters to Objective-C classes,
categories, forward declarations, and extensions as
appropriate. Perform semantic analysis of type bounds for type
parameters, both in isolation and across classes/categories/extensions
to ensure consistency.
Also handle (de-)serialization of Objective-C type parameter lists,
along with sundry other things one must do to add a new declaration to
Clang.
Note that Objective-C type parameters are typedef name declarations,
like typedefs and C++11 type aliases, in support of type erasure.
Part of rdar://problem/6294649.
llvm-svn: 241541
The patch is generated using this command:
$ tools/extra/clang-tidy/tool/run-clang-tidy.py -fix \
-checks=-*,llvm-namespace-comment -header-filter='llvm/.*|clang/.*' \
work/llvm/tools/clang
To reduce churn, not touching namespaces spanning less than 10 lines.
llvm-svn: 240270
Introduce context-sensitive, non-underscored nullability specifiers
(nonnull, nullable, null_unspecified) for Objective-C method return
types, method parameter types, and properties.
Introduce Objective-C-specific semantics, including computation of the
nullability of the result of a message send, merging of nullability
information from the @interface of a class into its @implementation,
etc .
This is the Objective-C part of rdar://problem/18868820.
llvm-svn: 240154
VarDeclBitfields contained bits which are never present in parameters.
Split these out so that ParmVarDeclBitfields wouldn't grow past 32-bits
if another field was added.
llvm-svn: 237648
I again added the "reasonable" assertions and they again fired during
a modules self-host.
This hopefully will un-break the self-host build bot. No test case handy
and adding one seems to have little or no value really.
llvm-svn: 233426
declaration name so that we mark declarations for emission in
a deterministic order (and in turn give them deterministic IDs).
This is the last for loop or data structure I can find by inspection of
the AST writer which doesn't use a deterministic order.
Found by inspection, no test case.
llvm-svn: 233348
updated decl contexts get emitted.
Since this code was added, we have newer vastly simpler code for
handling this. The code I'm removing was very expensive and also
generated unstable order of declarations which made module outputs
non-deterministic.
All of the tests continue to pass for me and I'm able to check the
difference between the .pcm files after merging modules together.
llvm-svn: 233251
Previously we'd deserialize the list of mem-initializers for a constructor when
we deserialized the declaration of the constructor. That could trigger a
significant amount of unnecessary work (pulling in all base classes
recursively, for a start) and was causing problems for the modules buildbot due
to cyclic deserializations. We now deserialize these on demand.
This creates a certain amount of duplication with the handling of
CXXBaseSpecifiers; I'll look into reducing that next.
llvm-svn: 233052
move the operator delete updating into a separate update record so we can cope
with updating another module's destructor's operator delete.
llvm-svn: 231735
We used to save out and eagerly load a (potentially huge) table of merged
formerly-canonical declarations when we loaded each module. This was extremely
inefficient in the presence of large amounts of merging, and didn't actually
save any merging lookup work, because we still needed to perform name lookup to
check that our merged declaration lists were complete. This also resulted in a
loss of laziness -- even if we only needed an early declaration of an entity, we
would eagerly pull in all declarations that had been merged into it regardless.
We now store the relevant fragments of the table within the declarations
themselves. In detail:
* The first declaration of each entity within a module stores a list of first
declarations from imported modules that are merged into it.
* Loading that declaration pre-loads those other entities, so that they appear
earlier within the redeclaration chain.
* The name lookup tables list the most recent local lookup result, if there
is one, or all directly-imported lookup results if not.
llvm-svn: 231424
undeserialized specializations (because we merged an imported declaration of
the same template since we last added one), don't bother reading in the
specializations themselves just so we can write out their IDs again.
llvm-svn: 230805
context as anonymous for merging purposes. They can't be found by their names,
so we merge them based on their position within the surrounding context.
llvm-svn: 228485
of that entity, ensure that the redeclaration chain is reordered properly on
reload. Otherwise, the result of name lookup for that entity may point to an
entity that is too old; if that's an injected friend name or the like, that
can result in the name not being found at all.
llvm-svn: 228371
Bitfield RefersToEnclosingLocal of Stmt::DeclRefExprBitfields renamed to RefersToCapturedVariable to reflect latest changes introduced in commit 224323. Also renamed method Expr::refersToEnclosingLocal() to Expr::refersToCapturedVariable() and comments for constant arguments.
No functional changes.
llvm-svn: 224329
initializers, and captured VLA types so that we can
answer questions like "is this a bit-field" without
looking at the enclosing DeclContext. NFC.
llvm-svn: 219522
on CXXRecordDecls when merging definitions, and make it pass by not trying to
save and restore this flag across AST serialization/deserialization. For
CXXRecordDecls, we have a separate mechanism to manage this.
llvm-svn: 216633
pattern of an alias template declaration. Use this to merge alias templates
properly when they're members of class template specializations.
llvm-svn: 216437
* Add abbreviation for CXXMethodDecl and for FunctionProtoType. These come up
a *lot* in C++ modules.
* Allow typedef declarations to use the abbreviation if they're class members,
or if they're used.
In passing, add more record name records for Clang AST node kinds.
The downside is that we had already used up our allotment of 12 abbreviations,
so this pushes us to an extra bit on each record to support the extra abbrev
kinds, which increases file size by ~1%. This patch *barely* pays for that
through the other improvements, but we've got room for another 18 abbrevs,
so we should be able to make it much more profitable with future changes.
llvm-svn: 214024
specialization from a module. (This can also happen for function template
specializations in PCHs if they're instantiated eagerly, because they're
constexpr or have a deduced return type.)
llvm-svn: 204547
Douglas Gregor