[APINotes] Avoid duplicate attributes when fields instantiate class templates

[susmonteiro]

If a C++ class template A is annotated via API Notes and another class B has a field of type A, we would apply the attributes from the API Notes twice. This happened during ActOnFields, so this change makes sure we stop processing API Notes for class template instantiations in this function.

rdar://166179307

[llvmbot]

@llvm/pr-subscribers-clang

Author: Susana Monteiro (susmonteiro)

Changes

If a C++ class template A is annotated via API Notes and another class B has a field of type A, we would apply the attributes from the API Notes twice. This happened during ActOnFields, so this change makes sure we stop processing API Notes for class template instantiations in this function.

rdar://166179307

---

Full diff: https://github.com/llvm/llvm-project/pull/173386.diff

4 Files Affected:

• (modified) clang/lib/Sema/SemaDecl.cpp (+2-1)
• (modified) clang/test/APINotes/Inputs/Headers/Templates.apinotes (+2)
• (modified) clang/test/APINotes/Inputs/Headers/Templates.h (+9)
• (modified) clang/test/APINotes/templates.cpp (+11)

diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index 5da665a5acad2..c44f4bd6b331a 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -20161,7 +20161,8 @@ void Sema::ActOnFields(Scope *S, SourceLocation RecLoc, Decl *EnclosingDecl,
       CDecl->setIvarRBraceLoc(RBrac);
     }
   }
-  ProcessAPINotes(Record);
+  if (!isa<ClassTemplateSpecializationDecl>(Record))
+    ProcessAPINotes(Record);
 }
 
 // Given an integral type, return the next larger integral type
diff --git a/clang/test/APINotes/Inputs/Headers/Templates.apinotes b/clang/test/APINotes/Inputs/Headers/Templates.apinotes
index b7336484da0c7..ded688b5a9076 100644
--- a/clang/test/APINotes/Inputs/Headers/Templates.apinotes
+++ b/clang/test/APINotes/Inputs/Headers/Templates.apinotes
@@ -3,3 +3,5 @@ Name: Templates
 Tags:
 - Name: Box
   SwiftImportAs: owned
+- Name: MoveOnly
+  SwiftCopyable: false
diff --git a/clang/test/APINotes/Inputs/Headers/Templates.h b/clang/test/APINotes/Inputs/Headers/Templates.h
index 2a86a46d4af27..cdb7c3b3fa2c0 100644
--- a/clang/test/APINotes/Inputs/Headers/Templates.h
+++ b/clang/test/APINotes/Inputs/Headers/Templates.h
@@ -8,3 +8,12 @@ struct Box {
 
 using FloatBox = Box<float>;
 using IntBox = Box<int>;
+
+template <typename T>
+struct MoveOnly {
+  T value;
+};
+
+struct MoveOnlyBox {
+  MoveOnly<int> value;
+};
diff --git a/clang/test/APINotes/templates.cpp b/clang/test/APINotes/templates.cpp
index 48109011e73a9..6d8b65a0d5f85 100644
--- a/clang/test/APINotes/templates.cpp
+++ b/clang/test/APINotes/templates.cpp
@@ -1,6 +1,7 @@
 // RUN: rm -rf %t && mkdir -p %t
 // RUN: %clang_cc1 -fmodules -fblocks -fimplicit-module-maps -fmodules-cache-path=%t/ModulesCache/Tmpl -fdisable-module-hash -fapinotes-modules -fsyntax-only -I %S/Inputs/Headers -F %S/Inputs/Frameworks %s -x c++
 // RUN: %clang_cc1 -fmodules -fblocks -fimplicit-module-maps -fmodules-cache-path=%t/ModulesCache/Tmpl -fdisable-module-hash -fapinotes-modules -I %S/Inputs/Headers -F %S/Inputs/Frameworks %s -ast-dump -ast-dump-filter Box -x c++ | FileCheck -check-prefix=CHECK-BOX %s
+// RUN: %clang_cc1 -fmodules -fblocks -fimplicit-module-maps -fmodules-cache-path=%t/ModulesCache/Tmpl -fdisable-module-hash -fapinotes-modules -I %S/Inputs/Headers -F %S/Inputs/Frameworks %s -ast-dump -ast-dump-filter MoveOnly -x c++ | FileCheck -check-prefix=CHECK-MOVEONLY %s
 
 #include "Templates.h"
 
@@ -10,3 +11,13 @@
 
 // Make sure the attributes aren't duplicated.
 // CHECK-BOX-NOT: SwiftAttrAttr {{.+}} <<invalid sloc>> "import_owned"
+
+// CHECK-MOVEONLY: Dumping MoveOnly:
+// CHECK-MOVEONLY-NEXT: ClassTemplateDecl {{.+}} imported in Templates MoveOnly
+// CHECK-MOVEONLY: SwiftAttrAttr {{.+}} <<invalid sloc>> "~Copyable"
+
+// CHECK-MOVEONLY-NEXT: ClassTemplateSpecializationDecl {{.+}} imported in Templates {{.+}} MoveOnly
+// CHECK-MOVEONLY: SwiftAttrAttr {{.+}} <<invalid sloc>> "~Copyable"
+
+// Make sure the attributes aren't duplicated.
+// CHECK-MOVEONLY-NOT: SwiftAttrAttr {{.+}} <<invalid sloc>> "~Copyable"

[Xazax-hun]

Overall, looks good to me. One question inline.