[clang] 7d26d6a - Sema: add support for `__attribute__((__swift_bridged_typedef__))`

[Saleem Abdulrasool via cfe-commits]

Author: Saleem Abdulrasool
Date: 2020-09-15T20:15:34Z
New Revision: 7d26d6a1b062f7ce820b02b39d102d5f8f15fa5f

URL: https://github.com/llvm/llvm-project/commit/7d26d6a1b062f7ce820b02b39d102d5f8f15fa5f
DIFF: https://github.com/llvm/llvm-project/commit/7d26d6a1b062f7ce820b02b39d102d5f8f15fa5f.diff

LOG: Sema: add support for `__attribute__((__swift_bridged_typedef__))`

Extend the semantic attributes that clang processes for Swift to include
`swift_bridged_typedef`.  This attribute enables typedefs to be bridged
into Swift with a bridged name.

This is based on the work of the original changes in
https://github.com/llvm/llvm-project-staging/commit/8afaf3aad2af43cfedca7a24cd817848c4e95c0c

Differential Revision: https://reviews.llvm.org/D87396
Reviewed By: Aaron Ballman

Added: 
    clang/test/AST/attr-swift_bridged_typedef.m
    clang/test/AST/attr-swift_bridged_typedef.mm
    clang/test/SemaObjC/attr-swift_bridged_typedef.m

Modified: 
    clang/include/clang/Basic/Attr.td
    clang/include/clang/Basic/AttrDocs.td
    clang/lib/Sema/SemaDeclAttr.cpp
    clang/test/Misc/pragma-attribute-supported-attributes-list.test

Removed: 
    


################################################################################
diff  --git a/clang/include/clang/Basic/Attr.td b/clang/include/clang/Basic/Attr.td
index 3221cf23c4b5..6df348618260 100644
--- a/clang/include/clang/Basic/Attr.td
+++ b/clang/include/clang/Basic/Attr.td
@@ -2130,6 +2130,12 @@ def Regparm : TypeAttr {
   let ASTNode = 0;
 }
 
+def SwiftBridgedTypedef : InheritableAttr {
+  let Spellings = [GNU<"swift_bridged_typedef">];
+  let Subjects = SubjectList<[TypedefName], ErrorDiag>;
+  let Documentation = [SwiftBridgedTypedefDocs];
+}
+
 def SwiftObjCMembers : Attr {
   let Spellings = [GNU<"swift_objc_members">];
   let Subjects = SubjectList<[ObjCInterface], ErrorDiag>;

diff  --git a/clang/include/clang/Basic/AttrDocs.td b/clang/include/clang/Basic/AttrDocs.td
index 939f52dae3d5..7aff443e9a12 100644
--- a/clang/include/clang/Basic/AttrDocs.td
+++ b/clang/include/clang/Basic/AttrDocs.td
@@ -3476,6 +3476,27 @@ Swift.
   }];
 }
 
+def SwiftBridgedTypedefDocs : Documentation {
+  let Category = SwiftDocs;
+  let Heading = "swift_bridged";
+  let Content = [{
+The ``swift_bridged_typedef`` attribute indicates that when the typedef to which
+the attribute appertains is imported into Swift, it should refer to the bridged
+Swift type (e.g. Swift's ``String``) rather than the Objective-C type as written
+(e.g. ``NSString``).
+
+  .. code-block:: c
+
+    @interface NSString;
+    typedef NSString *AliasedString __attribute__((__swift_bridged_typedef__));
+
+    extern void acceptsAliasedString(AliasedString _Nonnull parameter);
+
+In this case, the function ``acceptsAliasedString`` will be imported into Swift
+as a function which accepts a ``String`` type parameter.
+  }];
+}
+
 def SwiftObjCMembersDocs : Documentation {
   let Category = SwiftDocs;
   let Heading = "swift_objc_members";

diff  --git a/clang/lib/Sema/SemaDeclAttr.cpp b/clang/lib/Sema/SemaDeclAttr.cpp
index bf9d8497f5a2..02ffd752233d 100644
--- a/clang/lib/Sema/SemaDeclAttr.cpp
+++ b/clang/lib/Sema/SemaDeclAttr.cpp
@@ -7533,6 +7533,9 @@ static void ProcessDeclAttribute(Sema &S, Scope *scope, Decl *D,
     break;
 
   // Swift attributes.
+  case ParsedAttr::AT_SwiftBridgedTypedef:
+    handleSimpleAttribute<SwiftBridgedTypedefAttr>(S, D, AL);
+    break;
   case ParsedAttr::AT_SwiftError:
     handleSwiftError(S, D, AL);
     break;

diff  --git a/clang/test/AST/attr-swift_bridged_typedef.m b/clang/test/AST/attr-swift_bridged_typedef.m
new file mode 100644
index 000000000000..8c7c0987569e
--- /dev/null
+++ b/clang/test/AST/attr-swift_bridged_typedef.m
@@ -0,0 +1,9 @@
+// RUN: %clang_cc1 -fsyntax-only -ast-dump %s | FileCheck %s
+
+typedef struct T TBridged __attribute((__swift_bridged_typedef__));
+// CHECK: TypedefDecl {{.*}} TBridged 'struct T'
+// CHECK: SwiftBridgedTypedefAttr
+
+typedef struct T TBridged;
+// CHECK: TypedefDecl {{.*}} TBridged 'struct T'
+// CHECK: SwiftBridgedTypedefAttr

diff  --git a/clang/test/AST/attr-swift_bridged_typedef.mm b/clang/test/AST/attr-swift_bridged_typedef.mm
new file mode 100644
index 000000000000..44fd022d5ea7
--- /dev/null
+++ b/clang/test/AST/attr-swift_bridged_typedef.mm
@@ -0,0 +1,8 @@
+// RUN: %clang_cc1 -fsyntax-only %s -ast-dump | FileCheck %s
+
+ at interface NSString
+ at end
+
+using NSStringAlias __attribute__((__swift_bridged_typedef__)) = NSString *;
+// CHECK: TypeAliasDecl {{.*}} NSStringAlias 'NSString *'
+// CHECK: SwiftBridgedTypedefAttr

diff  --git a/clang/test/Misc/pragma-attribute-supported-attributes-list.test b/clang/test/Misc/pragma-attribute-supported-attributes-list.test
index dcf7cd2b7f1a..024081b02e3e 100644
--- a/clang/test/Misc/pragma-attribute-supported-attributes-list.test
+++ b/clang/test/Misc/pragma-attribute-supported-attributes-list.test
@@ -146,6 +146,7 @@
 // CHECK-NEXT: Section (SubjectMatchRule_function, SubjectMatchRule_variable_is_global, SubjectMatchRule_objc_method, SubjectMatchRule_objc_property)
 // CHECK-NEXT: SetTypestate (SubjectMatchRule_function_is_member)
 // CHECK-NEXT: SpeculativeLoadHardening (SubjectMatchRule_function, SubjectMatchRule_objc_method)
+// CHECK-NEXT: SwiftBridgedTypedef (SubjectMatchRule_type_alias)
 // CHECK-NEXT: SwiftContext (SubjectMatchRule_variable_is_parameter)
 // CHECK-NEXT: SwiftError (SubjectMatchRule_function, SubjectMatchRule_objc_method)
 // CHECK-NEXT: SwiftErrorResult (SubjectMatchRule_variable_is_parameter)

diff  --git a/clang/test/SemaObjC/attr-swift_bridged_typedef.m b/clang/test/SemaObjC/attr-swift_bridged_typedef.m
new file mode 100644
index 000000000000..2836b886a903
--- /dev/null
+++ b/clang/test/SemaObjC/attr-swift_bridged_typedef.m
@@ -0,0 +1,14 @@
+// RUN: %clang_cc1 -verify -fsyntax-only %s
+
+ at interface NSString
+ at end
+
+typedef NSString *NSStringAlias __attribute__((__swift_bridged_typedef__));
+
+typedef int IntAlias __attribute__((__swift_bridged_typedef__));
+
+struct __attribute__((swift_bridged_typedef)) S {};
+// expected-error at -1 {{'swift_bridged_typedef' attribute only applies to typedefs}}
+
+typedef unsigned char UnsignedChar __attribute__((__swift_bridged_typedef__("UnsignedChar")));
+// expected-error at -1 {{'__swift_bridged_typedef__' attribute takes no arguments}}