New loplugin:data

...following up on 1453c2c8f13bac64ecd1981af7cebf1c421808ac "prefer vector::data
to &vector[0]"

Change-Id: I7c113747d92d144a521d49b89384dd8bf1215c01
Reviewed-on: https://gerrit.libreoffice.org/72765
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <sbergman@redhat.com>

1 files changed, 84 insertions, 0 deletions

diff --git a/compilerplugins/clang/data.cxx b/compilerplugins/clang/data.cxx
new file mode 100644
index 000000000000..7e2f019e47a1
--- /dev/null
+++ b/compilerplugins/clang/data.cxx
@@ -0,0 +1,84 @@
+/* -*- 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/.
+ */
+
+#include "check.hxx"
+#include "compat.hxx"
+#include "plugin.hxx"
+
+// For std::array or std::vector x, replace &x[0] with x.data().
+
+namespace
+{
+class Data final : public loplugin::FilteringPlugin<Data>
+{
+public:
+    explicit Data(loplugin::InstantiationData const& data)
+        : FilteringPlugin(data)
+    {
+    }
+
+    bool VisitUnaryOperator(UnaryOperator const* expr)
+    {
+        if (ignoreLocation(expr))
+        {
+            return true;
+        }
+        if (expr->getOpcode() != UO_AddrOf)
+        {
+            return true;
+        }
+        auto const e1 = dyn_cast<CXXOperatorCallExpr>(expr->getSubExpr()->IgnoreParenImpCasts());
+        if (e1 == nullptr)
+        {
+            return true;
+        }
+        if (e1->getOperator() != OO_Subscript)
+        {
+            return true;
+        }
+        auto const t = e1->getArg(0)->getType();
+        auto const chk = loplugin::TypeCheck(t);
+        if (!(chk.Class("array").StdNamespace() || chk.Class("vector").StdNamespace()))
+        {
+            return true;
+        }
+        auto const e2 = e1->getArg(1);
+        if (e2->isValueDependent())
+        {
+            return true;
+        }
+        APSInt v;
+        if (!compat::EvaluateAsInt(e2, v, compiler.getASTContext()))
+        {
+            return true;
+        }
+        if (v != 0)
+        {
+            return true;
+        }
+        report(DiagnosticsEngine::Warning,
+               "use 'data' member function to access first element of %0", expr->getExprLoc())
+            << t << expr->getSourceRange();
+        return true;
+    }
+
+private:
+    void run() override
+    {
+        if (compiler.getLangOpts().CPlusPlus)
+        {
+            TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
+        }
+    }
+};
+
+static loplugin::Plugin::Registration<Data> reg("data");
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */