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authorNoel Grandin <noel.grandin@collabora.co.uk>2024-11-04 08:15:21 +0200
committerNoel Grandin <noel.grandin@collabora.co.uk>2024-11-13 13:08:16 +0100
commitfb745b54d223acc480a1f024c42806eadd0c5708 (patch)
tree657fa87768b7c1850a5432d5ec8589c85b2dafbb /compilerplugins
parentbcee366d82392b02745b0070a312624e7baa29d3 (diff)
new loplugin:reftotemp
look for places where we are taking a reference (i.e. "&") to a temporary object, which is misleading. Change-Id: Id0eb4dce3f1ca559f86e02edcbea3ca17bea8e76 Reviewed-on: https://gerrit.libreoffice.org/c/core/+/175978 Reviewed-by: Noel Grandin <noel.grandin@collabora.co.uk> Tested-by: Jenkins
Diffstat (limited to 'compilerplugins')
-rw-r--r--compilerplugins/clang/rangedforcopy.cxx4
-rw-r--r--compilerplugins/clang/reftotemp.cxx87
-rw-r--r--compilerplugins/clang/test/reftotemp.cxx25
3 files changed, 116 insertions, 0 deletions
diff --git a/compilerplugins/clang/rangedforcopy.cxx b/compilerplugins/clang/rangedforcopy.cxx
index 3ad407c358bb..16e7746afdcb 100644
--- a/compilerplugins/clang/rangedforcopy.cxx
+++ b/compilerplugins/clang/rangedforcopy.cxx
@@ -56,6 +56,10 @@ bool RangedForCopy::VisitCXXForRangeStmt( const CXXForRangeStmt* stmt )
if (!type->isRecordType() || type->isReferenceType() || type->isPointerType())
return true;
+ if (auto exprWithCleanups = dyn_cast<ExprWithCleanups>(varDecl->getInit()))
+ if (dyn_cast<CXXBindTemporaryExpr>(exprWithCleanups->getSubExpr()->IgnoreImpCasts()))
+ return true;
+
if (loplugin::TypeCheck(type).Class("__bit_const_reference").StdNamespace())
{
// With libc++ without _LIBCPP_ABI_BITSET_VECTOR_BOOL_CONST_SUBSCRIPT_RETURN_BOOL,
diff --git a/compilerplugins/clang/reftotemp.cxx b/compilerplugins/clang/reftotemp.cxx
new file mode 100644
index 000000000000..bd430d74fc6a
--- /dev/null
+++ b/compilerplugins/clang/reftotemp.cxx
@@ -0,0 +1,87 @@
+/* -*- 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 <cassert>
+#include <stack>
+
+#include "check.hxx"
+#include "plugin.hxx"
+#include "config_clang.h"
+
+/**
+look for places where we take a reference (i.e. "&") to a temporary value.
+
+Which is rather dodgy.
+
+*/
+namespace
+{
+class RefToTemp final : public loplugin::FilteringPlugin<RefToTemp>
+{
+public:
+ explicit RefToTemp(loplugin::InstantiationData const& data)
+ : FilteringPlugin(data)
+ {
+ }
+
+ bool VisitVarDecl(const VarDecl* varDecl)
+ {
+ if (ignoreLocation(varDecl))
+ return true;
+ // reference parameters might have a default temporary value, which is ok
+ if (isa<ParmVarDecl>(varDecl))
+ return true;
+ if (!varDecl->getType()->isReferenceType())
+ return true;
+ if (!varDecl->getInit())
+ return true;
+ if (!isTemporaryValue(varDecl->getInit()))
+ return true;
+ report(DiagnosticsEngine::Warning, "taking reference to temporary value",
+ varDecl->getBeginLoc())
+ << varDecl->getSourceRange();
+ return true;
+ }
+
+ bool isTemporaryValue(const Expr* expr)
+ {
+ if (dyn_cast<MaterializeTemporaryExpr>(expr))
+ return true;
+ if (auto exprWithCleanups = dyn_cast<ExprWithCleanups>(expr))
+ if (dyn_cast_or_null<MaterializeTemporaryExpr>(
+ exprWithCleanups->getSubExpr()->IgnoreImpCasts()))
+ return true;
+ return false;
+ }
+
+ bool preRun() override
+ {
+ if (!compiler.getLangOpts().CPlusPlus)
+ return false;
+ return true;
+ }
+
+private:
+ void run() override
+ {
+ if (preRun())
+ {
+ TraverseDecl(compiler.getASTContext().getTranslationUnitDecl());
+ }
+ }
+};
+
+loplugin::Plugin::Registration<RefToTemp> reftotemp("reftotemp");
+}
+
+#endif
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */
diff --git a/compilerplugins/clang/test/reftotemp.cxx b/compilerplugins/clang/test/reftotemp.cxx
new file mode 100644
index 000000000000..2d5d3fd969f8
--- /dev/null
+++ b/compilerplugins/clang/test/reftotemp.cxx
@@ -0,0 +1,25 @@
+/* -*- 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 <sal/config.h>
+#include <rtl/string.hxx>
+#include <rtl/ustring.hxx>
+
+namespace test1
+{
+OUString getString();
+void f()
+{
+ // expected-error@+1 {{taking reference to temporary value [loplugin:reftotemp]}}
+ const OUString& rToTemp = getString();
+ (void)rToTemp;
+}
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab cinoptions=b1,g0,N-s cinkeys+=0=break: */