[PATCH] libstdc++: Fix access issue in iota_view::_Sentinel [PR100690]
Patrick Palka
ppalka@redhat.com
Thu May 20 17:44:36 GMT 2021
Tested on x86_64-pc-linux-gnu, does this look OK for trunk/11/10?
libstdc++-v3/ChangeLog:
PR libstdc++/100690
* include/std/ranges (iota_view::_Sentinel::_M_distance_from):
Split out into this member function from ...
(iota_view::_Sentinel::operator-): ... here, for sake of access
checking.
* testsuite/std/ranges/iota/iota_view.cc:
---
libstdc++-v3/include/std/ranges | 8 ++++++--
libstdc++-v3/testsuite/std/ranges/iota/iota_view.cc | 11 +++++++++++
2 files changed, 17 insertions(+), 2 deletions(-)
diff --git a/libstdc++-v3/include/std/ranges b/libstdc++-v3/include/std/ranges
index 704f924557c..76add252ca6 100644
--- a/libstdc++-v3/include/std/ranges
+++ b/libstdc++-v3/include/std/ranges
@@ -499,6 +499,10 @@ namespace ranges
_M_equal(const _Iterator& __x) const
{ return __x._M_value == _M_bound; }
+ constexpr auto
+ _M_distance_from(const _Iterator& __x) const
+ { return _M_bound - __x._M_value; }
+
_Bound _M_bound = _Bound();
public:
@@ -515,12 +519,12 @@ namespace ranges
friend constexpr iter_difference_t<_Winc>
operator-(const _Iterator& __x, const _Sentinel& __y)
requires sized_sentinel_for<_Bound, _Winc>
- { return __x._M_value - __y._M_bound; }
+ { return -__y._M_distance_from(__x); }
friend constexpr iter_difference_t<_Winc>
operator-(const _Sentinel& __x, const _Iterator& __y)
requires sized_sentinel_for<_Bound, _Winc>
- { return -(__y - __x); }
+ { return __x._M_distance_from(__y); }
};
_Winc _M_value = _Winc();
diff --git a/libstdc++-v3/testsuite/std/ranges/iota/iota_view.cc b/libstdc++-v3/testsuite/std/ranges/iota/iota_view.cc
index be8695120ad..362ef1f7f78 100644
--- a/libstdc++-v3/testsuite/std/ranges/iota/iota_view.cc
+++ b/libstdc++-v3/testsuite/std/ranges/iota/iota_view.cc
@@ -80,6 +80,16 @@ test04()
// Verify we optimize away the 'bound' data member of an unbounded iota_view.
static_assert(sizeof(std::ranges::iota_view<char>) == 1);
+void
+test05()
+{
+ // PR libstdc++/100690
+ int x[] = {42, 42, 42};
+ auto r = std::views::iota(std::ranges::begin(x), std::ranges::cbegin(x) + 3);
+ VERIFY( r.end() - r.begin() == 3 );
+ VERIFY( r.begin() - r.end() == -3 );
+}
+
int
main()
{
@@ -87,4 +97,5 @@ main()
test02();
test03();
test04();
+ test05();
}
--
2.32.0.rc0
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