Teach loplugin:stringconstant about RTL_CONSTASCII_STRINGPARAM

Change-Id: I8ff0e104aad045f3835dc8facc760a8339b1d088

compilerplugins/clang/stringconstant.cxx

@@ -821,6 +821,20 @@ bool StringConstant::isStringConstant(
     assert(embeddedNuls != nullptr);
     assert(terminatingNul != nullptr);
     QualType t = expr->getType();
+    // Look inside RTL_CONSTASCII_STRINGPARAM:
+    if (loplugin::TypeCheck(t).Pointer().Const().Char()) {
+        auto e2 = dyn_cast<UnaryOperator>(expr);
+        if (e2 == nullptr || e2->getOpcode() != UO_AddrOf) {
+            return false;
+        }
+        auto e3 = dyn_cast<ArraySubscriptExpr>(
+            e2->getSubExpr()->IgnoreParenImpCasts());
+        if (e3 == nullptr || !isZero(e3->getIdx()->IgnoreParenImpCasts())) {
+            return false;
+        }
+        expr = e3->getBase()->IgnoreParenImpCasts();
+        t = expr->getType();
+    }
     if (!(t->isConstantArrayType() && t.isConstQualified()
           && (loplugin::TypeCheck(t->getAsArrayTypeUnsafe()->getElementType())
               .Char())))

compilerplugins/clang/typecheck.cxx

@@ -39,6 +39,16 @@ TypeCheck TypeCheck::LvalueReference() const {
     return TypeCheck();
 }
 
+TypeCheck TypeCheck::Pointer() const {
+    if (!type_.isNull()) {
+        auto const t = type_->getAs<clang::PointerType>();
+        if (t != nullptr) {
+            return TypeCheck(t->getPointeeType());
+        }
+    }
+    return TypeCheck();
+}
+
 TypeCheck TypeCheck::NotSubstTemplateTypeParmType() const {
     return
         (!type_.isNull()

compilerplugins/clang/typecheck.hxx

@@ -31,6 +31,8 @@ public:
 
     TerminalCheck Char() const;
 
+    TypeCheck Pointer() const;
+
     TypeCheck LvalueReference() const;
 
     template<std::size_t N> inline NamespaceCheck Class(char const (& id)[N])