From: Jonathan Wakely <jwakely@redhat.com>
Date: Wed, 31 Jan 2024 10:41:49 +0000 (+0000)
Subject: libstdc++: Avoid reusing moved-from iterators in PSTL tests [PR90276]
X-Git-Tag: basepoints/gcc-15~1396
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=723a7c1ad29523b9ddff53c7b147bffea56fbb63;p=thirdparty%2Fgcc.git

libstdc++: Avoid reusing moved-from iterators in PSTL tests [PR90276]

The reverse_invoker utility for PSTL tests uses forwarding references for
all parameters, but some of those parameters get forwarded to move
constructors which then leave the objects in a moved-from state. When
the parameters are forwarded a second time that results in making new
copies of moved-from iterators.  For libstdc++ debug mode iterators, the
moved-from state is singular, which means copying them will abort at
runtime.

The fix is to make copies of iterator arguments instead of forwarding
them.

The callers of reverse_invoker::operator() also forward the iterators
multiple times, but that's OK because reverse_invoker accepts them by
forwarding reference but then breaks the chain of forwarding and copies
them as lvalues.

libstdc++-v3/ChangeLog:

	PR libstdc++/90276
	* testsuite/util/pstl/test_utils.h (reverse_invoker): Do not use
	perfect forwarding for iterator arguments.
---

diff --git a/libstdc++-v3/testsuite/util/pstl/test_utils.h b/libstdc++-v3/testsuite/util/pstl/test_utils.h
index ed6d48b9471a..e35084eabb20 100644
--- a/libstdc++-v3/testsuite/util/pstl/test_utils.h
+++ b/libstdc++-v3/testsuite/util/pstl/test_utils.h
@@ -1083,18 +1083,18 @@ struct iterator_invoker<std::forward_iterator_tag, /*isReverse=*/std::true_type>
 template <typename IsReverse>
 struct reverse_invoker
 {
-    template <typename... Rest>
+    template <typename Policy, typename Op, typename... Rest>
     void
-    operator()(Rest&&... rest)
+    operator()(Policy&& exec, Op op, Rest&&... rest)
     {
         // Random-access iterator
-        iterator_invoker<std::random_access_iterator_tag, IsReverse>()(std::forward<Rest>(rest)...);
+        iterator_invoker<std::random_access_iterator_tag, IsReverse>()(std::forward<Policy>(exec), op, rest...);
 
         // Forward iterator
-        iterator_invoker<std::forward_iterator_tag, IsReverse>()(std::forward<Rest>(rest)...);
+        iterator_invoker<std::forward_iterator_tag, IsReverse>()(std::forward<Policy>(exec), op, rest...);
 
         // Bidirectional iterator
-        iterator_invoker<std::bidirectional_iterator_tag, IsReverse>()(std::forward<Rest>(rest)...);
+        iterator_invoker<std::bidirectional_iterator_tag, IsReverse>()(std::forward<Policy>(exec), op, rest...);
     }
 };