r196296 - Issue diagnostic when constructor or destructor

[Fariborz Jahanian]

Author: fjahanian
Date: Tue Dec  3 11:10:08 2013
New Revision: 196296

URL: http://llvm.org/viewvc/llvm-project?rev=196296&view=rev
Log:
Issue diagnostic when constructor or destructor
return void expression. // rdar://15366494
pr17759.

Modified:
    cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
    cfe/trunk/lib/Sema/SemaStmt.cpp
    cfe/trunk/test/SemaCXX/return.cpp

Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=196296&r1=196295&r2=196296&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
+++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Tue Dec  3 11:10:08 2013
@@ -6426,6 +6426,8 @@ def ext_return_has_void_expr : Extension
 def err_return_init_list : Error<
   "%select{void function|void method|constructor|destructor}1 %0 "
   "must not return a value">;
+def err_ctor_dtor_returns_void : Error<
+  "%select{constructor|destructor}1 %0 must not return void expression">;
 def warn_noreturn_function_has_return_expr : Warning<
   "function %0 declared 'noreturn' should not return">,
   InGroup<InvalidNoreturn>;

Modified: cfe/trunk/lib/Sema/SemaStmt.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaStmt.cpp?rev=196296&r1=196295&r2=196296&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaStmt.cpp (original)
+++ cfe/trunk/lib/Sema/SemaStmt.cpp Tue Dec  3 11:10:08 2013
@@ -2801,8 +2801,14 @@ Sema::ActOnReturnStmt(SourceLocation Ret
       } else if (!RetValExp->isTypeDependent()) {
         // C99 6.8.6.4p1 (ext_ since GCC warns)
         unsigned D = diag::ext_return_has_expr;
-        if (RetValExp->getType()->isVoidType())
-          D = diag::ext_return_has_void_expr;
+        if (RetValExp->getType()->isVoidType()) {
+          NamedDecl *CurDecl = getCurFunctionOrMethodDecl();
+          if (isa<CXXConstructorDecl>(CurDecl) ||
+              isa<CXXDestructorDecl>(CurDecl))
+            D = diag::err_ctor_dtor_returns_void;
+          else
+            D = diag::ext_return_has_void_expr;
+        }
         else {
           ExprResult Result = Owned(RetValExp);
           Result = IgnoredValueConversions(Result.take());
@@ -2812,9 +2818,15 @@ Sema::ActOnReturnStmt(SourceLocation Ret
           RetValExp = ImpCastExprToType(RetValExp,
                                         Context.VoidTy, CK_ToVoid).take();
         }
-
+        // return of void in constructor/destructor is illegal in C++.
+        if (D == diag::err_ctor_dtor_returns_void) {
+          NamedDecl *CurDecl = getCurFunctionOrMethodDecl();
+          Diag(ReturnLoc, D)
+            << CurDecl->getDeclName() << isa<CXXDestructorDecl>(CurDecl)
+            << RetValExp->getSourceRange();
+        }
         // return (some void expression); is legal in C++.
-        if (D != diag::ext_return_has_void_expr ||
+        else if (D != diag::ext_return_has_void_expr ||
             !getLangOpts().CPlusPlus) {
           NamedDecl *CurDecl = getCurFunctionOrMethodDecl();
 

Modified: cfe/trunk/test/SemaCXX/return.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaCXX/return.cpp?rev=196296&r1=196295&r2=196296&view=diff
==============================================================================
--- cfe/trunk/test/SemaCXX/return.cpp (original)
+++ cfe/trunk/test/SemaCXX/return.cpp Tue Dec  3 11:10:08 2013
@@ -102,3 +102,13 @@ namespace return_has_expr {
     }
   };
 }
+
+// rdar://15366494
+// pr17759
+namespace ctor_returns_void {
+  void f() {}
+  struct S { 
+    S() { return f(); }; // expected-error {{constructor 'S' must not return void expression}}
+    ~S() { return f(); } // expected-error {{destructor '~S' must not return void expression}}
+  };
+}