Implement support for -Wunused-variable, from Oscar Bonilla!

llvm-svn: 83577

2 files changed, 12 insertions, 3 deletions

diff --git a/clang/lib/Sema/SemaDecl.cpp b/clang/lib/Sema/SemaDecl.cpp
index fa6d623ae3d..c2a83cdc6f5 100644
--- a/clang/lib/Sema/SemaDecl.cpp
+++ b/clang/lib/Sema/SemaDecl.cpp
@@ -434,6 +434,12 @@ void Sema::ActOnPopScope(SourceLocation Loc, Scope *S) {
 
     if (!D->getDeclName()) continue;
 
+    // Diagnose unused variables in this scope.
+    if (!D->isUsed() && !D->hasAttr<UnusedAttr>() && isa<VarDecl>(D) && 
+        !isa<ParmVarDecl>(D) && !isa<ImplicitParamDecl>(D) && 
+        D->getDeclContext()->isFunctionOrMethod())
+	    Diag(D->getLocation(), diag::warn_unused_variable) << D->getDeclName();
+    
     // Remove this name from our lexical scope.
     IdResolver.RemoveDecl(D);
   }
diff --git a/clang/lib/Sema/SemaExpr.cpp b/clang/lib/Sema/SemaExpr.cpp
index c9525f39e55..c689a7ac2a5 100644
--- a/clang/lib/Sema/SemaExpr.cpp
+++ b/clang/lib/Sema/SemaExpr.cpp
@@ -6145,9 +6145,12 @@ void Sema::MarkDeclarationReferenced(SourceLocation Loc, Decl *D) {
   if (D->isUsed())
     return;
 
-  // Mark a parameter declaration "used", regardless of whether we're in a
-  // template or not.
-  if (isa<ParmVarDecl>(D))
+  // Mark a parameter or variable declaration "used", regardless of whether we're in a
+  // template or not. The reason for this is that unevaluated expressions
+  // (e.g. (void)sizeof()) constitute a use for warning purposes (-Wunused-variables and
+  // -Wunused-parameters)
+  if (isa<ParmVarDecl>(D) || 
+      (isa<VarDecl>(D) && D->getDeclContext()->isFunctionOrMethod()))
     D->setUsed(true);
 
   // Do not mark anything as "used" within a dependent context; wait for