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C++ Interop: import namespace aliases #37443

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Merged
merged 1 commit into from
May 23, 2021
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C++ Interop: import namespace aliases #37443

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38 changes: 36 additions & 2 deletions lib/ClangImporter/ImportDecl.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -2590,8 +2590,42 @@ namespace {
}

Decl *VisitNamespaceAliasDecl(const clang::NamespaceAliasDecl *decl) {
// FIXME: Implement once Swift has namespaces.
return nullptr;
Optional<ImportedName> correctSwiftName;
auto importedName = importFullName(decl, correctSwiftName);
auto name = importedName.getDeclName().getBaseIdentifier();
if (name.empty())
return nullptr;

if (correctSwiftName)
return importCompatibilityTypeAlias(decl, importedName,
*correctSwiftName);

auto dc =
Impl.importDeclContextOf(decl, importedName.getEffectiveContext());
if (!dc)
return nullptr;

auto aliasedDecl =
Impl.importDecl(decl->getAliasedNamespace(), getActiveSwiftVersion());
if (!aliasedDecl)
return nullptr;

Type aliasedType;
if (auto aliasedTypeDecl = dyn_cast<TypeDecl>(aliasedDecl))
aliasedType = aliasedTypeDecl->getDeclaredInterfaceType();
else if (auto aliasedExtDecl = dyn_cast<ExtensionDecl>(aliasedDecl))
// This happens if the alias points to its parent namespace.
aliasedType = aliasedExtDecl->getExtendedType();
else
return nullptr;

auto result = Impl.createDeclWithClangNode<TypeAliasDecl>(
decl, AccessLevel::Public, Impl.importSourceLoc(decl->getBeginLoc()),
SourceLoc(), name, Impl.importSourceLoc(decl->getLocation()),
/*GenericParams=*/nullptr, dc);
result->setUnderlyingType(aliasedType);

return result;
}

Decl *VisitLabelDecl(const clang::LabelDecl *decl) {
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31 changes: 31 additions & 0 deletions test/Interop/Cxx/namespace/Inputs/classes.h
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Expand Up @@ -40,4 +40,35 @@ struct BasicStruct {
};
} // namespace ClassesNS3

namespace GlobalAliasToNS1 = ClassesNS1;
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I was going to suggest a test that references a namespace in another module, but I think we need to sort out SR-14214 first.


namespace ClassesNS4 {
namespace AliasToGlobalNS1 = ::ClassesNS1;
namespace AliasToGlobalNS2 = ::ClassesNS1::ClassesNS2;

namespace ClassesNS5 {
struct BasicStruct {};
} // namespace ClassesNS5

namespace AliasToInnerNS5 = ClassesNS5;
namespace AliasToNS2 = ClassesNS1::ClassesNS2;

namespace AliasChainToNS1 = GlobalAliasToNS1;
namespace AliasChainToNS2 = AliasChainToNS1::ClassesNS2;
} // namespace ClassesNS4

Comment on lines +43 to +59
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@varungandhi-apple varungandhi-apple May 16, 2021 •
edited
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Are more complex test cases covered by other tests? For example, consider code with namespaces that are shadowed

namespace X { }
namespace Y { namespace X { }; namespace Z = X; /* IIUC, refers to ::Y::X */ }

or code with using namespace ABC. Do these get translated correctly?

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There wasn't a test for such case, but I've added it now. Also added a test for an alias pointing to its parent namespace, and a couple of other similar cases.

Using-directives & using-declarations currently aren't imported at all (these C++ constructs, along with inline namespaces, are among those that I don't know how to express ergonomically in Swift).

namespace ClassesNS5 {
struct BasicStruct {};
namespace AliasToAnotherNS5 = ClassesNS4::ClassesNS5;

namespace ClassesNS5 {
struct BasicStruct {};
namespace AliasToNS5NS5 = ClassesNS5;
} // namespace ClassesNS5

namespace AliasToGlobalNS5 = ::ClassesNS5;
namespace AliasToLocalNS5 = ClassesNS5;
namespace AliasToNS5 = ::ClassesNS5::ClassesNS5;
} // namespace ClassesNS5

#endif // TEST_INTEROP_CXX_NAMESPACE_INPUTS_CLASSES_H
4 changes: 4 additions & 0 deletions test/Interop/Cxx/namespace/classes-irgen.swift
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Expand Up @@ -6,6 +6,7 @@ import Classes
// CHECK: call i8* @{{_ZN10ClassesNS111BasicStruct11basicMemberEv|"\?basicMember@BasicStruct@ClassesNS1@@QEAAPEBDXZ"}}(%"struct.ClassesNS1::BasicStruct"*
// CHECK: call i8* @{{_ZN10ClassesNS110ClassesNS211BasicStruct11basicMemberEv|"\?basicMember@BasicStruct@ClassesNS2@ClassesNS1@@QEAAPEBDXZ"}}(%"struct.ClassesNS1::ClassesNS2::BasicStruct"*
// CHECK: call i8* @{{_ZN10ClassesNS311BasicStruct11basicMemberEv|"\?basicMember@BasicStruct@ClassesNS3@@QEAAPEBDXZ"}}(%"struct.ClassesNS3::BasicStruct"*
// CHECK: call i8* @{{_ZN10ClassesNS111BasicStruct11basicMemberEv|"\?basicMember@BasicStruct@ClassesNS1@@QEAAPEBDXZ"}}(%"struct.ClassesNS1::BasicStruct"*
// CHECK: ret void
public func basicTests() {
var basicStructInst = ClassesNS1.BasicStruct()
Expand All @@ -16,6 +17,9 @@ public func basicTests() {

var siblingBasicStruct = ClassesNS3.BasicStruct()
siblingBasicStruct.basicMember()

var basicStructViaAlias = ClassesNS4.AliasToGlobalNS1.BasicStruct()
basicStructViaAlias.basicMember()
}

// CHECK-LABEL: define {{.*}}void @"$s4main15forwardDeclaredyyF"()
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31 changes: 31 additions & 0 deletions test/Interop/Cxx/namespace/classes-module-interface.swift
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Expand Up @@ -32,3 +32,34 @@
// CHECK: }
// CHECK: }
// CHECK-NOT: extension

// CHECK: typealias GlobalAliasToNS1 = ClassesNS1
// CHECK: extension ClassesNS4 {
// CHECK: typealias AliasToGlobalNS1 = ClassesNS1
// CHECK: typealias AliasToGlobalNS2 = ClassesNS1.ClassesNS2
// CHECK: typealias AliasToInnerNS5 = ClassesNS4.ClassesNS5
// CHECK: typealias AliasToNS2 = ClassesNS1.ClassesNS2
// CHECK: typealias AliasChainToNS1 = ClassesNS1
// CHECK: typealias AliasChainToNS2 = ClassesNS1.ClassesNS2
// CHECK: }
// CHECK: extension ClassesNS4.ClassesNS5 {
// CHECK: struct BasicStruct {
// CHECK: init()
// CHECK: }
// CHECK: }
// CHECK: extension ClassesNS5 {
// CHECK: struct BasicStruct {
// CHECK: init()
// CHECK: }
// CHECK: typealias AliasToAnotherNS5 = ClassesNS4.ClassesNS5
// CHECK: typealias AliasToGlobalNS5 = ClassesNS5
// CHECK: typealias AliasToLocalNS5 = ClassesNS5.ClassesNS5
// CHECK: typealias AliasToNS5 = ClassesNS5.ClassesNS5
// CHECK: }
// CHECK: extension ClassesNS5.ClassesNS5 {
// CHECK: struct BasicStruct {
// CHECK: init()
// CHECK: }
// CHECK: typealias AliasToNS5NS5 = ClassesNS5.ClassesNS5
// CHECK: }
// CHECK-NOT: extension
4 changes: 4 additions & 0 deletions test/Interop/Cxx/namespace/classes.swift
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Expand Up @@ -20,6 +20,10 @@ NamespacesTestSuite.test("Basic classes") {
var siblingBasicStruct = ClassesNS3.BasicStruct()
let siblingMemberCString = siblingBasicStruct.basicMember()
expectEqual(String(cString: siblingMemberCString!), "ClassesNS3::BasicStruct::basicMember")

var basicStructViaAlias = ClassesNS4.AliasToGlobalNS1.BasicStruct()
let basicMemberViaAliasCString = basicStructViaAlias.basicMember()
expectEqual(String(cString: basicMemberViaAliasCString!), "ClassesNS1::BasicStruct::basicMember")
}

NamespacesTestSuite.test("Forward declared classes") {
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