From: Fariborz Jahanian <fjahanian@apple.com>
Date: Tue, 30 Mar 2010 18:22:15 +0000 (+0000)
Subject: Add Support for 'warn_unused_result" attribute on
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=f031774aa2638b4d3f487e7e44180c1f89b867ef;p=clang

Add Support for 'warn_unused_result" attribute on
objective-c methods. (radar 7418262).



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@99903 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/include/clang/Basic/DiagnosticSemaKinds.td b/include/clang/Basic/DiagnosticSemaKinds.td
index 154d3197f3..58c40cf338 100644
--- a/include/clang/Basic/DiagnosticSemaKinds.td
+++ b/include/clang/Basic/DiagnosticSemaKinds.td
@@ -783,8 +783,9 @@ def warn_redeclaration_without_attribute_prev_attribute_ignored : Warning<
 def warn_attribute_ignored : Warning<"%0 attribute ignored">;
 def warn_attribute_precede_definition : Warning<
   "attribute declaration must precede definition">;
-def warn_attribute_void_function : Warning<
-  "attribute %0 cannot be applied to functions without return value">;
+def warn_attribute_void_function_method : Warning<
+  "attribute %0 cannot be applied to "
+  "%select{functions|Objective-C method}1 without return value">;
 def warn_attribute_weak_on_field : Warning<
   "__weak attribute cannot be specified on a field declaration">;
 def warn_attribute_weak_on_local : Warning<
diff --git a/lib/AST/Expr.cpp b/lib/AST/Expr.cpp
index 6a71e925d9..b4e5a5d960 100644
--- a/lib/AST/Expr.cpp
+++ b/lib/AST/Expr.cpp
@@ -914,8 +914,15 @@ bool Expr::isUnusedResultAWarning(SourceLocation &Loc, SourceRange &R1,
   case CXXConstructExprClass:
     return false;
 
-  case ObjCMessageExprClass:
+  case ObjCMessageExprClass: {
+    const ObjCMessageExpr *ME = cast<ObjCMessageExpr>(this);
+    const ObjCMethodDecl *MD = ME->getMethodDecl();
+    if (MD && MD->getAttr<WarnUnusedResultAttr>()) {
+      Loc = getExprLoc();
+      return true;
+    }
     return false;
+  }
 
   case ObjCImplicitSetterGetterRefExprClass: {   // Dot syntax for message send.
 #if 0
diff --git a/lib/Sema/SemaDeclAttr.cpp b/lib/Sema/SemaDeclAttr.cpp
index b3041129db..d12dec4561 100644
--- a/lib/Sema/SemaDeclAttr.cpp
+++ b/lib/Sema/SemaDeclAttr.cpp
@@ -837,18 +837,24 @@ static void HandleWarnUnusedResult(Decl *D, const AttributeList &Attr, Sema &S)
     return;
   }
 
-  if (!isFunction(D)) {
+  if (!isFunction(D) && !isa<ObjCMethodDecl>(D)) {
     S.Diag(Attr.getLoc(), diag::warn_attribute_wrong_decl_type)
       << Attr.getName() << 0 /*function*/;
     return;
   }
 
-  if (getFunctionType(D)->getResultType()->isVoidType()) {
-    S.Diag(Attr.getLoc(), diag::warn_attribute_void_function)
-      << Attr.getName();
+  if (isFunction(D) && getFunctionType(D)->getResultType()->isVoidType()) {
+    S.Diag(Attr.getLoc(), diag::warn_attribute_void_function_method)
+      << Attr.getName() << 0;
     return;
   }
-
+  if (const ObjCMethodDecl *MD = dyn_cast<ObjCMethodDecl>(D))
+    if (MD->getResultType()->isVoidType()) {
+      S.Diag(Attr.getLoc(), diag::warn_attribute_void_function_method)
+      << Attr.getName() << 1;
+      return;
+    }
+  
   D->addAttr(::new (S.Context) WarnUnusedResultAttr());
 }
 
diff --git a/lib/Sema/SemaStmt.cpp b/lib/Sema/SemaStmt.cpp
index 733022aac3..1e37bb00c4 100644
--- a/lib/Sema/SemaStmt.cpp
+++ b/lib/Sema/SemaStmt.cpp
@@ -119,7 +119,13 @@ void Sema::DiagnoseUnusedExprResult(const Stmt *S) {
       }
     }        
   }
-
+  else if (const ObjCMessageExpr *ME = dyn_cast<ObjCMessageExpr>(E)) {
+    const ObjCMethodDecl *MD = ME->getMethodDecl();
+    if (MD && MD->getAttr<WarnUnusedResultAttr>()) {
+      Diag(Loc, diag::warn_unused_call) << R1 << R2 << "warn_unused_result";
+      return;
+    }
+  }
   Diag(Loc, DiagID) << R1 << R2;
 }
 
diff --git a/test/SemaObjC/method-warn-unused-attribute.m b/test/SemaObjC/method-warn-unused-attribute.m
index d9dcf996ec..042f4422f8 100644
--- a/test/SemaObjC/method-warn-unused-attribute.m
+++ b/test/SemaObjC/method-warn-unused-attribute.m
@@ -1,8 +1,16 @@
 // RUN: %clang_cc1  -fsyntax-only -Wunused-value -verify %s
 
 @interface INTF
-// Currently this is rejected by both GCC and Clang (and Clang was crashing on it).
-- (id) foo __attribute__((warn_unused_result)); // expected-warning{{warning: 'warn_unused_result' attribute only applies to function types}}
+- (id) foo __attribute__((warn_unused_result)); 
+- (void) garf __attribute__((warn_unused_result)); // expected-warning {{attribute 'warn_unused_result' cannot be applied to Objective-C method without return value}}
+- (int) fee __attribute__((warn_unused_result));
++ (int) c __attribute__((warn_unused_result));
 @end
 
+void foo(INTF *a) {
+  [a garf];
+  [a fee]; // expected-warning {{ignoring return value of function declared with warn_unused_result attribute}}
+  [INTF c]; // expected-warning {{ignoring return value of function declared with warn_unused_result attribute}}
+}
+