compiler check to compare SAL_WARN/LOG areas against sal/inc/sal/log-areas.dox

Some of the areas are guesses I've added after seeing them, whoever feels reponsible
for whichever part of the code feel free to adjust them.

Change-Id: I2192de84d51cc2bc7c28fa84019d38b465985d15

compilerplugins/clang/sallogareas.hxx

@@ -0,0 +1,39 @@
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * Based on LLVM/Clang.
+ *
+ * This file is distributed under the University of Illinois Open Source
+ * License. See LICENSE.TXT for details.
+ *
+ */
+
+#ifndef SALLOGAREAS_H
+#define SALLOGAREAS_H
+
+#include <set>
+
+#include "compileplugin.hxx"
+
+namespace loplugin
+{
+
+class SalLogAreas
+    : public RecursiveASTVisitor< SalLogAreas >
+    , public Plugin
+    {
+    public:
+        explicit SalLogAreas( ASTContext& context );
+        void run();
+        bool VisitFunctionDecl( FunctionDecl* function );
+        bool VisitCallExpr( CallExpr* call );
+    private:
+        void checkArea( StringRef area, SourceLocation location );
+        void readLogAreas();
+        const FunctionDecl* inFunction;
+        std::set< std::string > logAreas;
+    };
+
+} // namespace
+
+#endif // SALLOGAREAS_H