Re: [PATCH][_GLIBCXX_DEBUG] Add basic_string::starts_with/ends_with checks

["François Dumont" <frs.dumont@gmail.com>]

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I spent more time on this.

Is there some discussion in the C++ Standard Committee to do something 
like what I've done ? I guess adding nullptr_t overloads for all the 
methods taking pointer is not an option, is it ?

Note that compilation fails but despite the dg-do xfail the test ends up 
FAIL and not XFAIL. Is this the correct syntax:
// { dg-do compile { target c++2a xfail *-*-* } }
?

Thanks,
François


On 15/08/22 22:26, François Dumont wrote:
> With the patch !
>
> On 14/08/22 17:32, François Dumont wrote:
>> I think we can add those checks.
>>
>> Note that I wonder if it was needed as in basic_string_view I see 
>> usages of __attribute__((__nonnull__)). But running the test I saw no 
>> impact even after I try to apply this attribute to the 
>> starts_with/ends_with methods themselves.
>>
>> Also note that several checks like the ones I am adding here are 
>> XFAILS when using 'make check' because of the segfault rather than on 
>> a proper debug checks. Would you prefer to add dg-require-debug-mode 
>> to those ?
>>
>>     libstdc++: [_GLIBCXX_DEBUG] Add 
>> basic_string::starts_with/ends_with checks
>>
>>     Add simple checks on C string parameters which should not be null.
>>
>>     Review null string checks to show:
>>     _String != nullptr
>>
>>     rather than:
>>     _String != 0
>>
>>     libstdc++-v3/ChangeLog:
>>
>>             * include/bits/basic_string.h (starts_with, ends_with): 
>> Add __glibcxx_check_string.
>>             * include/bits/cow_string.h (starts_with, ends_with): 
>> Likewise.
>>             * include/debug/debug.h: Use nullptr rather than '0' in 
>> checks in C++11.
>>             * include/debug/string: Likewise.
>>             * 
>> testsuite/21_strings/basic_string/operations/ends_with/char.cc: Use 
>> __gnu_test::string.
>>             * 
>> testsuite/21_strings/basic_string/operations/ends_with/wchar_t.cc: 
>> Use __gnu_test::wstring.
>>             * 
>> testsuite/21_strings/basic_string/operations/starts_with/wchar_t.cc: 
>> Use __gnu_test::wstring.
>>             * 
>> testsuite/21_strings/basic_string/operations/starts_with/char.cc: Use 
>> __gnu_test::string.
>>             * 
>> testsuite/21_strings/basic_string/operations/ends_with/char_neg.cc: 
>> New test.
>>             * 
>> testsuite/21_strings/basic_string/operations/ends_with/wchar_t_neg.cc: 
>> New test.
>>             * 
>> testsuite/21_strings/basic_string/operations/starts_with/char_neg.cc: 
>> New test.
>>             * 
>> testsuite/21_strings/basic_string/operations/starts_with/wchar_t_neg.cc: 
>> New test.
>>
>> Tested under linux normal and debug modes.
>>
>> François
>>
>>

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diff --git a/libstdc++-v3/include/bits/basic_string.h b/libstdc++-v3/include/bits/basic_string.h
index d06330e6c48..1be42e415f5 100644
--- a/libstdc++-v3/include/bits/basic_string.h
+++ b/libstdc++-v3/include/bits/basic_string.h
@@ -3407,6 +3407,9 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
 	return __sv_type(this->data(), this->size()).starts_with(__x);
       }
 
+      bool
+      starts_with(nullptr_t) const noexcept = delete;
+
       constexpr bool
       ends_with(basic_string_view<_CharT, _Traits> __x) const noexcept
       { return __sv_type(this->data(), this->size()).ends_with(__x); }
@@ -3421,6 +3424,9 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
 	__glibcxx_requires_string(__x);
 	return __sv_type(this->data(), this->size()).ends_with(__x);
       }
+
+      bool
+      ends_with(nullptr_t) const noexcept = delete;
 #endif // C++20
 
 #if __cplusplus > 202002L
diff --git a/libstdc++-v3/include/bits/cow_string.h b/libstdc++-v3/include/bits/cow_string.h
index 59b36a1006a..f8f0959554d 100644
--- a/libstdc++-v3/include/bits/cow_string.h
+++ b/libstdc++-v3/include/bits/cow_string.h
@@ -3019,6 +3019,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	return __sv_type(this->data(), this->size()).starts_with(__x);
       }
 
+      bool
+      starts_with(nullptr_t) const noexcept = delete;
+
       bool
       ends_with(basic_string_view<_CharT, _Traits> __x) const noexcept
       { return __sv_type(this->data(), this->size()).ends_with(__x); }
@@ -3033,6 +3036,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	__glibcxx_requires_string(__x);
 	return __sv_type(this->data(), this->size()).ends_with(__x);
       }
+
+      bool
+      ends_with(nullptr_t) const noexcept = delete;
 #endif // C++20
 
 #if __cplusplus > 202011L
diff --git a/libstdc++-v3/testsuite/21_strings/basic_string/operations/ends_with/char_neg.cc b/libstdc++-v3/testsuite/21_strings/basic_string/operations/ends_with/char_neg.cc
index 7a7b8dd077d..273e9a6a564 100644
--- a/libstdc++-v3/testsuite/21_strings/basic_string/operations/ends_with/char_neg.cc
+++ b/libstdc++-v3/testsuite/21_strings/basic_string/operations/ends_with/char_neg.cc
@@ -15,10 +15,8 @@
 // with this library; see the file COPYING3.  If not see
 // <http://www.gnu.org/licenses/>.
 //
-// { dg-options "-std=gnu++2a -O0" }
-// { dg-do run { target c++2a xfail *-*-* } }
-
-#define _GLIBCXX_DEBUG_PEDANTIC
+// { dg-options "-std=gnu++2a" }
+// { dg-do compile { target c++2a xfail *-*-* } }
 
 #include <testsuite_string.h>
 
diff --git a/libstdc++-v3/testsuite/21_strings/basic_string/operations/ends_with/wchar_t_neg.cc b/libstdc++-v3/testsuite/21_strings/basic_string/operations/ends_with/wchar_t_neg.cc
index a6881bf406b..07588ea2bf7 100644
--- a/libstdc++-v3/testsuite/21_strings/basic_string/operations/ends_with/wchar_t_neg.cc
+++ b/libstdc++-v3/testsuite/21_strings/basic_string/operations/ends_with/wchar_t_neg.cc
@@ -15,10 +15,8 @@
 // with this library; see the file COPYING3.  If not see
 // <http://www.gnu.org/licenses/>.
 //
-// { dg-options "-std=gnu++2a -O0" }
-// { dg-do run { target c++2a xfail *-*-* } }
-
-#define _GLIBCXX_DEBUG_PEDANTIC
+// { dg-options "-std=gnu++2a" }
+// { dg-do compile { target c++2a xfail *-*-* } }
 
 #include <testsuite_string.h>
 
diff --git a/libstdc++-v3/testsuite/21_strings/basic_string/operations/starts_with/char_neg.cc b/libstdc++-v3/testsuite/21_strings/basic_string/operations/starts_with/char_neg.cc
index f357aef2289..9b6b0d2ddda 100644
--- a/libstdc++-v3/testsuite/21_strings/basic_string/operations/starts_with/char_neg.cc
+++ b/libstdc++-v3/testsuite/21_strings/basic_string/operations/starts_with/char_neg.cc
@@ -15,10 +15,8 @@
 // with this library; see the file COPYING3.  If not see
 // <http://www.gnu.org/licenses/>.
 //
-// { dg-options "-std=gnu++2a -O0" }
-// { dg-do run { target c++2a xfail *-*-* } }
-
-#define _GLIBCXX_DEBUG_PEDANTIC
+// { dg-options "-std=gnu++2a" }
+// { dg-do compile { target c++2a xfail *-*-* } }
 
 #include <testsuite_string.h>
 
diff --git a/libstdc++-v3/testsuite/21_strings/basic_string/operations/starts_with/wchar_t_neg.cc b/libstdc++-v3/testsuite/21_strings/basic_string/operations/starts_with/wchar_t_neg.cc
index 90065a459b6..1ea10d1ab39 100644
--- a/libstdc++-v3/testsuite/21_strings/basic_string/operations/starts_with/wchar_t_neg.cc
+++ b/libstdc++-v3/testsuite/21_strings/basic_string/operations/starts_with/wchar_t_neg.cc
@@ -15,10 +15,8 @@
 // with this library; see the file COPYING3.  If not see
 // <http://www.gnu.org/licenses/>.
 //
-// { dg-options "-std=gnu++2a -O0" }
-// { dg-do run { target c++2a xfail *-*-* } }
-
-#define _GLIBCXX_DEBUG_PEDANTIC
+// { dg-options "-std=gnu++2a" }
+// { dg-do compile { target c++2a xfail *-*-* } }
 
 #include <testsuite_string.h>