clang/sema: disallow more than one 'onweship_takes' with different classes

Author: pskrgag

clang/include/clang/Basic/DiagnosticSemaKinds.td

@@ -3328,6 +3328,10 @@ def err_ownership_returns_index_mismatch : Error<
   "'ownership_returns' attribute index does not match; here it is %0">;
 def note_ownership_returns_index_mismatch : Note<
   "declared with index %0 here">;
+def err_ownership_takes_class_mismatch : Error<
+  "'ownership_takes' attribute class does not match; here it is '%0'">;
+def note_ownership_takes_class_mismatch : Note<
+  "declared with class '%0' here">;
 def err_format_strftime_third_parameter : Error<
   "strftime format attribute requires 3rd parameter to be 0">;
 def err_format_attribute_not : Error<"format argument not a string type">;

clang/lib/Sema/SemaDeclAttr.cpp

@@ -1537,6 +1537,16 @@ static void handleOwnershipAttr(Sema &S, Decl *D, const ParsedAttr &AL) {
                 << Idx.getSourceIndex() << Ex->getSourceRange();
           return;
         }
+      } else if (K == OwnershipAttr::Takes &&
+                 I->getOwnKind() == OwnershipAttr::Takes) {
+        if (I->getModule()->getName() != ModuleName) {
+          S.Diag(I->getLocation(), diag::err_ownership_takes_class_mismatch)
+              << I->getModule()->getName();
+          S.Diag(AL.getLoc(), diag::note_ownership_takes_class_mismatch)
+              << ModuleName << Ex->getSourceRange();
+
+          return;
+        }
       }
     }
     OwnershipArgs.push_back(Idx);

clang/test/Sema/attr-ownership.c

@@ -24,3 +24,7 @@ void f15(int, int)
 void f16(int *i, int *j) __attribute__((ownership_holds(foo, 1))) __attribute__((ownership_holds(foo, 1))); // OK, same index
 void f17(void*) __attribute__((ownership_takes(__, 1)));
 void f18() __attribute__((ownership_takes(foo, 1)));  // expected-warning {{'ownership_takes' attribute only applies to non-K&R-style functions}}
+
+int f19(void *)
+  __attribute__((ownership_takes(foo, 1)))    // expected-error {{'ownership_takes' attribute class does not match; here it is 'foo'}}
+  __attribute__((ownership_takes(foo1, 1)));  // expected-note {{declared with class 'foo1' here}}