[cfe-commits] r100574 - in /cfe/trunk: include/clang/Basic/DiagnosticSemaKinds.td lib/Sema/SemaStmt.cpp test/Sema/unused-expr.c

[John McCall]

Author: rjmccall
Date: Tue Apr  6 17:24:14 2010
New Revision: 100574

URL: http://llvm.org/viewvc/llvm-project?rev=100574&view=rev
Log:
Devote a special diagnostic to the typo
  (void*) someFunction(5, 10, 15, 20);
where the cast is presumably meant to be to 'void'.


Modified:
    cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
    cfe/trunk/lib/Sema/SemaStmt.cpp
    cfe/trunk/test/Sema/unused-expr.c

Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=100574&r1=100573&r2=100574&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
+++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Tue Apr  6 17:24:14 2010
@@ -2359,6 +2359,9 @@
   InGroup<GNU>;
 def warn_unused_expr : Warning<"expression result unused">,
   InGroup<UnusedValue>;
+def warn_unused_voidptr : Warning<
+  "expression result unused; should this cast be to 'void'?">,
+  InGroup<UnusedValue>;
 def warn_unused_property_expr : Warning<
   "property access result unused - getters should not have side effects">,
   InGroup<UnusedValue>;

Modified: cfe/trunk/lib/Sema/SemaStmt.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaStmt.cpp?rev=100574&r1=100573&r2=100574&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaStmt.cpp (original)
+++ cfe/trunk/lib/Sema/SemaStmt.cpp Tue Apr  6 17:24:14 2010
@@ -20,6 +20,7 @@
 #include "clang/AST/ExprObjC.h"
 #include "clang/AST/StmtObjC.h"
 #include "clang/AST/StmtCXX.h"
+#include "clang/AST/TypeLoc.h"
 #include "clang/Lex/Preprocessor.h"
 #include "clang/Basic/TargetInfo.h"
 #include "llvm/ADT/STLExtras.h"
@@ -126,6 +127,22 @@
       return;
     }
   }
+
+  // Diagnose "(void*) blah" as a typo for "(void) blah".
+  else if (const CStyleCastExpr *CE = dyn_cast<CStyleCastExpr>(E)) {
+    TypeSourceInfo *TI = CE->getTypeInfoAsWritten();
+    QualType T = TI->getType();
+
+    // We really do want to use the non-canonical type here.
+    if (T == Context.VoidPtrTy) {
+      PointerTypeLoc TL = cast<PointerTypeLoc>(TI->getTypeLoc());
+
+      Diag(Loc, diag::warn_unused_voidptr)
+        << FixItHint::CreateRemoval(TL.getStarLoc());
+      return;
+    }
+  }
+
   Diag(Loc, DiagID) << R1 << R2;
 }
 

Modified: cfe/trunk/test/Sema/unused-expr.c
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Sema/unused-expr.c?rev=100574&r1=100573&r2=100574&view=diff
==============================================================================
--- cfe/trunk/test/Sema/unused-expr.c (original)
+++ cfe/trunk/test/Sema/unused-expr.c Tue Apr  6 17:24:14 2010
@@ -104,3 +104,9 @@
 }
 
 void t9() __attribute__((warn_unused_result)); // expected-warning {{attribute 'warn_unused_result' cannot be applied to functions without return value}}
+
+// rdar://7410924
+void *some_function(void);
+void t10() {
+  (void*) some_function(); //expected-warning {{expression result unused; should this cast be to 'void'?}}
+}