Implement variance for Objective-C type parameters.
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
diff --git a/clang/lib/AST/ASTContext.cpp b/clang/lib/AST/ASTContext.cpp
index 58d703a..fb96301 100644
--- a/clang/lib/AST/ASTContext.cpp
+++ b/clang/lib/AST/ASTContext.cpp
@@ -6943,20 +6943,62 @@
compareObjCProtocolsByName);
}
+/// Determine whether the first type is a subtype of the second.
+static bool canAssignObjCObjectTypes(ASTContext &ctx, QualType lhs,
+ QualType rhs) {
+ // Common case: two object pointers.
+ const ObjCObjectPointerType *lhsOPT = lhs->getAs<ObjCObjectPointerType>();
+ const ObjCObjectPointerType *rhsOPT = rhs->getAs<ObjCObjectPointerType>();
+ if (lhsOPT && rhsOPT)
+ return ctx.canAssignObjCInterfaces(lhsOPT, rhsOPT);
+
+ // Two block pointers.
+ const BlockPointerType *lhsBlock = lhs->getAs<BlockPointerType>();
+ const BlockPointerType *rhsBlock = rhs->getAs<BlockPointerType>();
+ if (lhsBlock && rhsBlock)
+ return ctx.typesAreBlockPointerCompatible(lhs, rhs);
+
+ // If either is an unqualified 'id' and the other is a block, it's
+ // acceptable.
+ if ((lhsOPT && lhsOPT->isObjCIdType() && rhsBlock) ||
+ (rhsOPT && rhsOPT->isObjCIdType() && lhsBlock))
+ return true;
+
+ return false;
+}
+
// Check that the given Objective-C type argument lists are equivalent.
-static bool sameObjCTypeArgs(const ASTContext &ctx, ArrayRef<QualType> lhsArgs,
+static bool sameObjCTypeArgs(ASTContext &ctx,
+ const ObjCInterfaceDecl *iface,
+ ArrayRef<QualType> lhsArgs,
ArrayRef<QualType> rhsArgs,
bool stripKindOf) {
if (lhsArgs.size() != rhsArgs.size())
return false;
+ ObjCTypeParamList *typeParams = iface->getTypeParamList();
for (unsigned i = 0, n = lhsArgs.size(); i != n; ++i) {
- if (!ctx.hasSameType(lhsArgs[i], rhsArgs[i])) {
+ if (ctx.hasSameType(lhsArgs[i], rhsArgs[i]))
+ continue;
+
+ switch (typeParams->begin()[i]->getVariance()) {
+ case ObjCTypeParamVariance::Invariant:
if (!stripKindOf ||
!ctx.hasSameType(lhsArgs[i].stripObjCKindOfType(ctx),
rhsArgs[i].stripObjCKindOfType(ctx))) {
return false;
}
+ break;
+
+ case ObjCTypeParamVariance::Covariant:
+ if (!canAssignObjCObjectTypes(ctx, lhsArgs[i], rhsArgs[i]))
+ return false;
+ break;
+
+ case ObjCTypeParamVariance::Contravariant:
+ if (!canAssignObjCObjectTypes(ctx, rhsArgs[i], lhsArgs[i]))
+ return false;
+ break;
}
}
@@ -6989,7 +7031,8 @@
bool anyChanges = false;
if (LHS->isSpecialized() && RHS->isSpecialized()) {
// Both have type arguments, compare them.
- if (!sameObjCTypeArgs(*this, LHS->getTypeArgs(), RHS->getTypeArgs(),
+ if (!sameObjCTypeArgs(*this, LHS->getInterface(),
+ LHS->getTypeArgs(), RHS->getTypeArgs(),
/*stripKindOf=*/true))
return QualType();
} else if (LHS->isSpecialized() != RHS->isSpecialized()) {
@@ -7037,7 +7080,8 @@
bool anyChanges = false;
if (LHS->isSpecialized() && RHS->isSpecialized()) {
// Both have type arguments, compare them.
- if (!sameObjCTypeArgs(*this, LHS->getTypeArgs(), RHS->getTypeArgs(),
+ if (!sameObjCTypeArgs(*this, LHS->getInterface(),
+ LHS->getTypeArgs(), RHS->getTypeArgs(),
/*stripKindOf=*/true))
return QualType();
} else if (LHS->isSpecialized() != RHS->isSpecialized()) {
@@ -7127,7 +7171,8 @@
// If the RHS is specializd, compare type arguments.
if (RHSSuper->isSpecialized() &&
- !sameObjCTypeArgs(*this, LHS->getTypeArgs(), RHSSuper->getTypeArgs(),
+ !sameObjCTypeArgs(*this, LHS->getInterface(),
+ LHS->getTypeArgs(), RHSSuper->getTypeArgs(),
/*stripKindOf=*/true)) {
return false;
}
diff --git a/clang/lib/AST/ASTDumper.cpp b/clang/lib/AST/ASTDumper.cpp
index 3dec23d..c95922b 100644
--- a/clang/lib/AST/ASTDumper.cpp
+++ b/clang/lib/AST/ASTDumper.cpp
@@ -1475,6 +1475,19 @@
void ASTDumper::VisitObjCTypeParamDecl(const ObjCTypeParamDecl *D) {
dumpName(D);
+ switch (D->getVariance()) {
+ case ObjCTypeParamVariance::Invariant:
+ break;
+
+ case ObjCTypeParamVariance::Covariant:
+ OS << " covariant";
+ break;
+
+ case ObjCTypeParamVariance::Contravariant:
+ OS << " contravariant";
+ break;
+ }
+
if (D->hasExplicitBound())
OS << " bounded";
dumpType(D->getUnderlyingType());
diff --git a/clang/lib/AST/ASTImporter.cpp b/clang/lib/AST/ASTImporter.cpp
index d264e96..8460030 100644
--- a/clang/lib/AST/ASTImporter.cpp
+++ b/clang/lib/AST/ASTImporter.cpp
@@ -3452,6 +3452,8 @@
ObjCTypeParamDecl *Result = ObjCTypeParamDecl::Create(
Importer.getToContext(), DC,
+ D->getVariance(),
+ Importer.Import(D->getVarianceLoc()),
D->getIndex(),
Importer.Import(D->getLocation()),
Name.getAsIdentifierInfo(),
diff --git a/clang/lib/AST/DeclObjC.cpp b/clang/lib/AST/DeclObjC.cpp
index 714824b0..da4bc54 100644
--- a/clang/lib/AST/DeclObjC.cpp
+++ b/clang/lib/AST/DeclObjC.cpp
@@ -1198,28 +1198,36 @@
void ObjCTypeParamDecl::anchor() { }
ObjCTypeParamDecl *ObjCTypeParamDecl::Create(ASTContext &ctx, DeclContext *dc,
+ ObjCTypeParamVariance variance,
+ SourceLocation varianceLoc,
unsigned index,
SourceLocation nameLoc,
IdentifierInfo *name,
SourceLocation colonLoc,
TypeSourceInfo *boundInfo) {
- return new (ctx, dc) ObjCTypeParamDecl(ctx, dc, index, nameLoc, name, colonLoc,
- boundInfo);
+ return new (ctx, dc) ObjCTypeParamDecl(ctx, dc, variance, varianceLoc, index,
+ nameLoc, name, colonLoc, boundInfo);
}
ObjCTypeParamDecl *ObjCTypeParamDecl::CreateDeserialized(ASTContext &ctx,
unsigned ID) {
- return new (ctx, ID) ObjCTypeParamDecl(ctx, nullptr, 0, SourceLocation(),
+ return new (ctx, ID) ObjCTypeParamDecl(ctx, nullptr,
+ ObjCTypeParamVariance::Invariant,
+ SourceLocation(), 0, SourceLocation(),
nullptr, SourceLocation(), nullptr);
}
SourceRange ObjCTypeParamDecl::getSourceRange() const {
+ SourceLocation startLoc = VarianceLoc;
+ if (startLoc.isInvalid())
+ startLoc = getLocation();
+
if (hasExplicitBound()) {
- return SourceRange(getLocation(),
+ return SourceRange(startLoc,
getTypeSourceInfo()->getTypeLoc().getEndLoc());
}
- return SourceRange(getLocation());
+ return SourceRange(startLoc);
}
//===----------------------------------------------------------------------===//
diff --git a/clang/lib/AST/DeclPrinter.cpp b/clang/lib/AST/DeclPrinter.cpp
index 3e5e7c0..3202d8c 100644
--- a/clang/lib/AST/DeclPrinter.cpp
+++ b/clang/lib/AST/DeclPrinter.cpp
@@ -974,6 +974,19 @@
Out << ", ";
}
+ switch (Param->getVariance()) {
+ case ObjCTypeParamVariance::Invariant:
+ break;
+
+ case ObjCTypeParamVariance::Covariant:
+ Out << "__covariant ";
+ break;
+
+ case ObjCTypeParamVariance::Contravariant:
+ Out << "__contravariant ";
+ break;
+ }
+
Out << Param->getDeclName().getAsString();
if (Param->hasExplicitBound()) {