[gcc r10-10932] libstdc++: Add valid range checks to std::span constructors [PR98421]

[gcc r10-10932] libstdc++: Add valid range checks to std::span constructors [PR98421]

[Jonathan Wakely]

https://gcc.gnu.org/g:de802e4736613a585dcfd508acf73033f18aa4da

commit r10-10932-gde802e4736613a585dcfd508acf73033f18aa4da
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Tue Aug 31 17:34:51 2021 +0100

    libstdc++: Add valid range checks to std::span constructors [PR98421]
    
    Signed-off-by: Jonathan Wakely <jwakely@redhat.com>
    
    libstdc++-v3/ChangeLog:
    
            PR libstdc++/98421
            * include/std/span (span(Iter, size_type), span(Iter, Iter)):
            Add valid range checks.
            * testsuite/23_containers/span/cons_1_assert_neg.cc: New test.
            * testsuite/23_containers/span/cons_2_assert_neg.cc: New test.
    
    (cherry picked from commit ef7becc9c8a48804d3fd9dac032f7b33e561a612)

Diff:
---
 libstdc++-v3/include/std/span                              |  2 ++
 .../testsuite/23_containers/span/cons_1_assert_neg.cc      | 14 ++++++++++++++
 .../testsuite/23_containers/span/cons_2_assert_neg.cc      | 14 ++++++++++++++
 3 files changed, 30 insertions(+)

diff --git a/libstdc++-v3/include/std/span b/libstdc++-v3/include/std/span
index 35df1a64c0e..b2a1ea3f0a2 100644
--- a/libstdc++-v3/include/std/span
+++ b/libstdc++-v3/include/std/span
@@ -165,6 +165,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	    {
 	      __glibcxx_assert(__count == _Extent);
 	    }
+	  __glibcxx_requires_valid_range(__first, __first + __count);
 	}
 
       template<contiguous_iterator _It, sized_sentinel_for<_It> _End>
@@ -180,6 +181,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	    {
 	      __glibcxx_assert((__last - __first) == _Extent);
 	    }
+	  __glibcxx_requires_valid_range(__first, __last);
 	}
 
       template<size_t _ArrayExtent>
diff --git a/libstdc++-v3/testsuite/23_containers/span/cons_1_assert_neg.cc b/libstdc++-v3/testsuite/23_containers/span/cons_1_assert_neg.cc
new file mode 100644
index 00000000000..2f555125453
--- /dev/null
+++ b/libstdc++-v3/testsuite/23_containers/span/cons_1_assert_neg.cc
@@ -0,0 +1,14 @@
+// { dg-options "-std=gnu++2a" }
+// { dg-do run { xfail *-*-* } }
+// { dg-require-effective-target c++2a }
+
+#undef _GLIBCXX_DEBUG
+#define _GLIBCXX_DEBUG
+#include <span>
+#include <vector>
+
+int main()
+{
+  std::vector<int> v(2);
+  std::span<int, std::dynamic_extent> s(v.begin(), 3);
+}
diff --git a/libstdc++-v3/testsuite/23_containers/span/cons_2_assert_neg.cc b/libstdc++-v3/testsuite/23_containers/span/cons_2_assert_neg.cc
new file mode 100644
index 00000000000..efef0e608ba
--- /dev/null
+++ b/libstdc++-v3/testsuite/23_containers/span/cons_2_assert_neg.cc
@@ -0,0 +1,14 @@
+// { dg-options "-std=gnu++2a" }
+// { dg-do run { xfail *-*-* } }
+// { dg-require-effective-target c++2a }
+
+#undef _GLIBCXX_DEBUG
+#define _GLIBCXX_DEBUG
+#include <span>
+#include <vector>
+
+int main()
+{
+  std::vector<int> v(2), w(1);
+  std::span<int, std::dynamic_extent> s(v.begin(), w.end());
+}