1 files changed, 156 insertions, 0 deletions
diff --git a/compilerplugins/clang/conststringvar.cxx b/compilerplugins/clang/conststringvar.cxx
new file mode 100644
index 0000000000..99cfb01c06
--- /dev/null
+++ b/compilerplugins/clang/conststringvar.cxx
@@ -0,0 +1,156 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4; fill-column: 100 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+#ifndef LO_CLANG_SHARED_PLUGINS
+
+#include <set>
+#include <stack>
+
+#include "check.hxx"
+#include "plugin.hxx"
+
+// Find non-const vars of 'char const *' type initialized with a const expr,
+// that could likely be const (and will then probably trigger further
+// loplugin:stringconstant findings).
+
+namespace {
+
+class ConstStringVar:
+    public loplugin::FilteringPlugin<ConstStringVar>
+{
+public:
+    explicit ConstStringVar(loplugin::InstantiationData const & data):
+        FilteringPlugin(data) {}
+
+    bool preRun() override {
+        return compiler.getLangOpts().CPlusPlus;
+            // clang::Expr::isCXX11ConstantExpr only works for C++
+    }
+
+    void postRun() override {
+        for (auto v: vars_) {
+            report(
+                DiagnosticsEngine::Warning,
+                "variable is only used as rvalue, should be const",
+                v->getLocation())
+                << v->getSourceRange();
+        }
+    }
+
+    void run() override {
+        if (preRun() && TraverseDecl(compiler.getASTContext().getTranslationUnitDecl())) {
+            postRun();
+        }
+    }
+
+    bool PreTraverseImplicitCastExpr(ImplicitCastExpr * expr) {
+        bool match;
+        switch (expr->getCastKind()) {
+        case CK_NoOp:
+            // OString CharPtrDetector ctor:
+            match = bool(
+                loplugin::TypeCheck(expr->getType()).Const().Pointer().Const()
+                .Char());
+            break;
+        case CK_LValueToRValue:
+            match = true;
+            break;
+        default:
+            match = false;
+            break;
+        }
+        bool pushed = false;
+        if (match) {
+            if (auto dr = dyn_cast<DeclRefExpr>(
+                    expr->getSubExpr()->IgnoreParenImpCasts()))
+            {
+                if (auto vd = dyn_cast<VarDecl>(dr->getDecl())) {
+                    if (vars_.find(vd->getCanonicalDecl()) != vars_.end()) {
+                        casted_.push(dr);
+                        pushed = true;
+                    }
+                }
+            }
+        }
+        pushed_.push(pushed);
+        return true;
+    }
+    bool PostTraverseImplicitCastExpr(ImplicitCastExpr *, bool) {
+        bool pushed = pushed_.top();
+        pushed_.pop();
+        if (pushed) {
+            casted_.pop();
+        }
+        return true;
+    }
+    bool TraverseImplicitCastExpr(ImplicitCastExpr * expr) {
+        bool ret = true;
+        if (PreTraverseImplicitCastExpr(expr))
+        {
+            ret = FilteringPlugin::TraverseImplicitCastExpr(expr);
+            PostTraverseImplicitCastExpr(expr, ret);
+        }
+       return ret;
+    }
+
+    bool VisitVarDecl(VarDecl const * decl) {
+        if (ignoreLocation(decl)) {
+            return true;
+        }
+        if (decl != decl->getCanonicalDecl()) {
+            return true;
+        }
+        if (isa<ParmVarDecl>(decl) || loplugin::hasExternalLinkage(decl)) {
+            return true;
+        }
+        if (!loplugin::TypeCheck(decl->getType()).NonConstVolatile().Pointer()
+            .Const().Char())
+        {
+            return true;
+        }
+        auto init = decl->getAnyInitializer();
+        if (init == nullptr) {
+            return true;
+        }
+        if (init->isInstantiationDependent()) {
+            // avoid problems with isCXX11ConstantExpr in template code
+            return true;
+        }
+        APValue v;
+        if (!init->isCXX11ConstantExpr(compiler.getASTContext(), &v)) {
+            return true;
+        }
+        vars_.insert(decl);
+        return true;
+    }
+
+    bool VisitDeclRefExpr(DeclRefExpr const * expr) {
+        if (!casted_.empty() && expr == casted_.top()) {
+            return true;
+        }
+        auto vd = dyn_cast<VarDecl>(expr->getDecl());
+        if (vd == nullptr) {
+            return true;
+        }
+        vars_.erase(vd->getCanonicalDecl());
+        return true;
+    }
+
+private:
+    std::set<VarDecl const *> vars_;
+    std::stack<DeclRefExpr const *> casted_;
+    std::stack<bool> pushed_;
+};
+
+loplugin::Plugin::Registration<ConstStringVar> conststringvar("conststringvar");
+
+}
+
+#endif // LO_CLANG_SHARED_PLUGINS
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */