[gcc r16-8392] libstdc++: [_GLIBCXX_DEBUG] Fix COW string valid range check
Francois Dumont
fdumont@gcc.gnu.org
Wed Apr 1 16:59:53 GMT 2026
https://gcc.gnu.org/g:c0b659db1adcf84c04629cd8aeda89f1d2047e2a
commit r16-8392-gc0b659db1adcf84c04629cd8aeda89f1d2047e2a
Author: François Dumont <frs.dumont@gmail.com>
Date: Mon Mar 30 22:18:50 2026 +0200
libstdc++: [_GLIBCXX_DEBUG] Fix COW string valid range check
In revision 698a6af5dcbae5d935bcda8a461dea8458c658dc the _GLIBCXX_DEBUG code
for the Library Defect 438 has been removed as starting in C++11 the iterator
type is constrained through the _RequireInputIter requirement.
But the COW basic_string implementation used when _GLIBCXX_USE_CXX11_ABI=0 is
missing the _RequireInputIter constraint on a number of methods resulting in test
failures.
For the moment move the culprit __glibcxx_requires_valid_range call in the COW
basic_string implementation in a method where the iterator type has already been
checked.
libstdc++-v3/ChangeLog:
* include/bits/cow_string.h
(basic_string::replace(iterator, iterator, _InputIte, _InputIte)): Move
__glibcxx_requires_valid_range to...
(basic_string::_M_replace_dispatch(iterator, iterator, _InputIte,
_InputIte, __fase_type)): ...here.
* testsuite/21_strings/basic_string/debug/append_neg.cc: New test case.
* testsuite/21_strings/basic_string/debug/assign_neg.cc: New test case.
* testsuite/21_strings/basic_string/debug/construct_neg.cc: New test case.
* testsuite/21_strings/basic_string/debug/insert_neg.cc: New test case.
* testsuite/21_strings/basic_string/debug/replace_neg.cc: New test case.
Co-authored-by: Jonathan Wakely <jwakely@redhat.com>
Reviewed-by: Jonathan Wakely <jwakely@redhat.com>
Diff:
---
libstdc++-v3/include/bits/cow_string.h | 2 +-
.../21_strings/basic_string/debug/append_neg.cc | 19 +++++++++++++++++++
.../21_strings/basic_string/debug/assign_neg.cc | 19 +++++++++++++++++++
.../21_strings/basic_string/debug/construct_neg.cc | 17 +++++++++++++++++
.../21_strings/basic_string/debug/insert_neg.cc | 19 +++++++++++++++++++
.../21_strings/basic_string/debug/replace_neg.cc | 20 ++++++++++++++++++++
6 files changed, 95 insertions(+), 1 deletion(-)
diff --git a/libstdc++-v3/include/bits/cow_string.h b/libstdc++-v3/include/bits/cow_string.h
index 6cf002243729..df71185e556d 100644
--- a/libstdc++-v3/include/bits/cow_string.h
+++ b/libstdc++-v3/include/bits/cow_string.h
@@ -2124,7 +2124,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
{
_GLIBCXX_DEBUG_PEDASSERT(_M_ibegin() <= __i1 && __i1 <= __i2
&& __i2 <= _M_iend());
- __glibcxx_requires_valid_range(__k1, __k2);
typedef typename std::__is_integer<_InputIterator>::__type _Integral;
return _M_replace_dispatch(__i1, __i2, __k1, __k2, _Integral());
}
@@ -3833,6 +3832,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
_M_replace_dispatch(iterator __i1, iterator __i2, _InputIterator __k1,
_InputIterator __k2, __false_type)
{
+ __glibcxx_requires_valid_range(__k1, __k2);
const basic_string __s(__k1, __k2);
const size_type __n1 = __i2 - __i1;
_M_check_length(__n1, __s.size(), "basic_string::_M_replace_dispatch");
diff --git a/libstdc++-v3/testsuite/21_strings/basic_string/debug/append_neg.cc b/libstdc++-v3/testsuite/21_strings/basic_string/debug/append_neg.cc
new file mode 100644
index 000000000000..befe83a84f35
--- /dev/null
+++ b/libstdc++-v3/testsuite/21_strings/basic_string/debug/append_neg.cc
@@ -0,0 +1,19 @@
+// { dg-do run { xfail *-*-* } }
+// { dg-require-debug-mode "" }
+
+#include <vector>
+#include <string>
+
+void test01()
+{
+ std::vector<char> v1(10, 'a');
+ std::string s2;
+
+ s2.append(v1.begin() + 7, v1.begin() + 2);
+}
+
+int main()
+{
+ test01();
+ return 0;
+}
diff --git a/libstdc++-v3/testsuite/21_strings/basic_string/debug/assign_neg.cc b/libstdc++-v3/testsuite/21_strings/basic_string/debug/assign_neg.cc
new file mode 100644
index 000000000000..5f32c170f504
--- /dev/null
+++ b/libstdc++-v3/testsuite/21_strings/basic_string/debug/assign_neg.cc
@@ -0,0 +1,19 @@
+// { dg-do run { xfail *-*-* } }
+// { dg-require-debug-mode "" }
+
+#include <vector>
+#include <string>
+
+void test01()
+{
+ std::vector<char> v1(10, 'a');
+ std::string s2;
+
+ s2.assign(v1.begin() + 7, v1.begin() + 2);
+}
+
+int main()
+{
+ test01();
+ return 0;
+}
diff --git a/libstdc++-v3/testsuite/21_strings/basic_string/debug/construct_neg.cc b/libstdc++-v3/testsuite/21_strings/basic_string/debug/construct_neg.cc
new file mode 100644
index 000000000000..1ac933d43091
--- /dev/null
+++ b/libstdc++-v3/testsuite/21_strings/basic_string/debug/construct_neg.cc
@@ -0,0 +1,17 @@
+// { dg-do run { xfail *-*-* } }
+// { dg-require-debug-mode "" }
+
+#include <vector>
+#include <string>
+
+void test01()
+{
+ std::vector<char> v1(10, 'a');
+ std::string s2(v1.begin() + 7, v1.begin() + 2);
+}
+
+int main()
+{
+ test01();
+ return 0;
+}
diff --git a/libstdc++-v3/testsuite/21_strings/basic_string/debug/insert_neg.cc b/libstdc++-v3/testsuite/21_strings/basic_string/debug/insert_neg.cc
new file mode 100644
index 000000000000..95530ef2a510
--- /dev/null
+++ b/libstdc++-v3/testsuite/21_strings/basic_string/debug/insert_neg.cc
@@ -0,0 +1,19 @@
+// { dg-do run { xfail *-*-* } }
+// { dg-require-debug-mode "" }
+
+#include <vector>
+#include <string>
+
+void test01()
+{
+ std::vector<char> v1(10, 'a');
+ std::string s2;
+
+ s2.insert(s2.begin(), v1.begin() + 7, v1.begin() + 2);
+}
+
+int main()
+{
+ test01();
+ return 0;
+}
diff --git a/libstdc++-v3/testsuite/21_strings/basic_string/debug/replace_neg.cc b/libstdc++-v3/testsuite/21_strings/basic_string/debug/replace_neg.cc
new file mode 100644
index 000000000000..fd3df9e8539e
--- /dev/null
+++ b/libstdc++-v3/testsuite/21_strings/basic_string/debug/replace_neg.cc
@@ -0,0 +1,20 @@
+// { dg-do run { xfail *-*-* } }
+// { dg-require-debug-mode "" }
+
+#include <vector>
+#include <string>
+
+void test01()
+{
+ std::vector<char> v1(10, 'a');
+ std::string s2 = "bbbbbbbbbb";
+
+ s2.replace(s2.begin(), s2.begin() + 5,
+ v1.begin() + 7, v1.begin() + 2);
+}
+
+int main()
+{
+ test01();
+ return 0;
+}
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