Decorate string_view members with nonnull attribute

The C++ committee has confirmed that passing a null pointer to the
unary basic_string_view constructor is undefined. This removes the check
from our implementation, and adds the nonnull attribute to warn when the
compiler can detect undefined input.

	* include/std/string_view (basic_string_view(const CharT*)): Remove
	check for null pointer and add nonnull attribute.
	(compare(const CharT*), compare(size_type, size_type, const CharT*))
	(find(const CharT*, size_type), rfind(const CharT*, size_type))
	(find_first_of(const CharT*, size_type))
	(find_last_of(const CharT*, size_type))
	(find_first_not_of(const CharT*, size_type))
	(find_last_not_of(const CharT*, size_type)): Add nonnull attribute.
	* testsuite/21_strings/basic_string_view/cons/char/nonnull.cc: New.
	* testsuite/21_strings/basic_string_view/operations/compare/char/
	nonnull.cc: New.
	* testsuite/21_strings/basic_string_view/operations/find/char/
	nonnull.cc: New.
	* testsuite/21_strings/basic_string_view/operations/rfind/char/
	nonnull.cc: New.

From-SVN: r261638

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 482f64ee4604289dd7d3d793e2c13f90793d38dd..b7cef6057b19c664ababfd35838f5a8b2a4fc299 100644 (file)
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,5 +1,21 @@
 2018-06-15  Jonathan Wakely  <jwakely@redhat.com>
 
+       * include/std/string_view (basic_string_view(const CharT*)): Remove
+       check for null pointer and add nonnull attribute.
+       (compare(const CharT*), compare(size_type, size_type, const CharT*))
+       (find(const CharT*, size_type), rfind(const CharT*, size_type))
+       (find_first_of(const CharT*, size_type))
+       (find_last_of(const CharT*, size_type))
+       (find_first_not_of(const CharT*, size_type))
+       (find_last_not_of(const CharT*, size_type)): Add nonnull attribute.
+       * testsuite/21_strings/basic_string_view/cons/char/nonnull.cc: New.
+       * testsuite/21_strings/basic_string_view/operations/compare/char/
+       nonnull.cc: New.
+       * testsuite/21_strings/basic_string_view/operations/find/char/
+       nonnull.cc: New.
+       * testsuite/21_strings/basic_string_view/operations/rfind/char/
+       nonnull.cc: New.
+
        PR libstdc++/86168
        * include/bits/random.h (random_device(const string&)): Remove
        default argument.

diff --git a/libstdc++-v3/include/std/string_view b/libstdc++-v3/include/std/string_view
index 9f39df853e8d8a42c925ea4c0ee54befd0ce32be..f84664ca286c29dece7ba2d05a942f7784f18e39 100644 (file)
--- a/libstdc++-v3/include/std/string_view
+++ b/libstdc++-v3/include/std/string_view
@@ -96,8 +96,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
       constexpr basic_string_view(const basic_string_view&) noexcept = default;
 
-      constexpr basic_string_view(const _CharT* __str) noexcept
-      : _M_len{__str == nullptr ? 0 : traits_type::length(__str)},
+      __attribute__((__nonnull__)) constexpr
+      basic_string_view(const _CharT* __str) noexcept
+      : _M_len{traits_type::length(__str)},
        _M_str{__str}
       { }
 
@@ -270,11 +271,11 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
        return this->substr(__pos1, __n1).compare(__str.substr(__pos2, __n2));
       }
 
-      constexpr int
+      __attribute__((__nonnull__)) constexpr int
       compare(const _CharT* __str) const noexcept
       { return this->compare(basic_string_view{__str}); }
 
-      constexpr int
+      __attribute__((__nonnull__)) constexpr int
       compare(size_type __pos1, size_type __n1, const _CharT* __str) const
       { return this->substr(__pos1, __n1).compare(basic_string_view{__str}); }
 
@@ -296,7 +297,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       constexpr size_type
       find(const _CharT* __str, size_type __pos, size_type __n) const noexcept;
 
-      constexpr size_type
+      __attribute__((__nonnull__)) constexpr size_type
       find(const _CharT* __str, size_type __pos = 0) const noexcept
       { return this->find(__str, __pos, traits_type::length(__str)); }
 
@@ -310,7 +311,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       constexpr size_type
       rfind(const _CharT* __str, size_type __pos, size_type __n) const noexcept;
 
-      constexpr size_type
+      __attribute__((__nonnull__)) constexpr size_type
       rfind(const _CharT* __str, size_type __pos = npos) const noexcept
       { return this->rfind(__str, __pos, traits_type::length(__str)); }
 
@@ -323,9 +324,10 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       { return this->find(__c, __pos); }
 
       constexpr size_type
-      find_first_of(const _CharT* __str, size_type __pos, size_type __n) const noexcept;
+      find_first_of(const _CharT* __str, size_type __pos,
+                   size_type __n) const noexcept;
 
-      constexpr size_type
+      __attribute__((__nonnull__)) constexpr size_type
       find_first_of(const _CharT* __str, size_type __pos = 0) const noexcept
       { return this->find_first_of(__str, __pos, traits_type::length(__str)); }
 
@@ -342,7 +344,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       find_last_of(const _CharT* __str, size_type __pos,
                   size_type __n) const noexcept;
 
-      constexpr size_type
+      __attribute__((__nonnull__)) constexpr size_type
       find_last_of(const _CharT* __str, size_type __pos = npos) const noexcept
       { return this->find_last_of(__str, __pos, traits_type::length(__str)); }
 
@@ -358,7 +360,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       find_first_not_of(const _CharT* __str,
                        size_type __pos, size_type __n) const noexcept;
 
-      constexpr size_type
+      __attribute__((__nonnull__)) constexpr size_type
       find_first_not_of(const _CharT* __str, size_type __pos = 0) const noexcept
       {
        return this->find_first_not_of(__str, __pos,
@@ -377,7 +379,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
       find_last_not_of(const _CharT* __str,
                       size_type __pos, size_type __n) const noexcept;
 
-      constexpr size_type
+      __attribute__((__nonnull__)) constexpr size_type
       find_last_not_of(const _CharT* __str,
                       size_type __pos = npos) const noexcept
       {

diff --git a/libstdc++-v3/testsuite/21_strings/basic_string_view/cons/char/nonnull.cc b/libstdc++-v3/testsuite/21_strings/basic_string_view/cons/char/nonnull.cc
new file mode 100644 (file)
index 0000000..463ece7
--- /dev/null
+++ b/libstdc++-v3/testsuite/21_strings/basic_string_view/cons/char/nonnull.cc
@@ -0,0 +1,29 @@
+// Copyright (C) 2018 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+// { dg-options "-std=gnu++17 -Wnonnull" }
+// { dg-do compile { target c++17 } }
+
+#include <string_view>
+
+void
+test01()
+{
+  std::string_view s((const char*)nullptr); // { dg-warning "null arg" }
+  std::string_view t((char*)nullptr);      // { dg-warning "null arg" }
+  std::string_view u(nullptr);             // { dg-warning "null arg" }
+}

diff --git a/libstdc++-v3/testsuite/21_strings/basic_string_view/cons/wchar_t/nonnull.cc b/libstdc++-v3/testsuite/21_strings/basic_string_view/cons/wchar_t/nonnull.cc
new file mode 100644 (file)
index 0000000..8df6142
--- /dev/null
+++ b/libstdc++-v3/testsuite/21_strings/basic_string_view/cons/wchar_t/nonnull.cc
@@ -0,0 +1,29 @@
+// Copyright (C) 2018 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+// { dg-options "-std=gnu++17 -Wnonnull" }
+// { dg-do compile { target c++17 } }
+
+#include <string_view>
+
+void
+test01()
+{
+  std::wstring_view s((const wchar_t*)nullptr);        // { dg-warning "null arg" }
+  std::wstring_view t((wchar_t*)nullptr);      // { dg-warning "null arg" }
+  std::wstring_view u(nullptr);                        // { dg-warning "null arg" }
+}

diff --git a/libstdc++-v3/testsuite/21_strings/basic_string_view/operations/compare/char/nonnull.cc b/libstdc++-v3/testsuite/21_strings/basic_string_view/operations/compare/char/nonnull.cc
new file mode 100644 (file)
index 0000000..1d12b70
--- /dev/null
+++ b/libstdc++-v3/testsuite/21_strings/basic_string_view/operations/compare/char/nonnull.cc
@@ -0,0 +1,29 @@
+// Copyright (C) 2018 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+// { dg-options "-std=gnu++17 -Wnonnull" }
+// { dg-do compile { target c++17 } }
+
+#include <string_view>
+
+int
+test01()
+{
+  std::string_view s = "abcd";
+  return s.compare((const char*)nullptr);      // { dg-warning "null arg" }
+  return s.compare(0, 2, (const char*)nullptr);        // { dg-warning "null arg" }
+}

diff --git a/libstdc++-v3/testsuite/21_strings/basic_string_view/operations/find/char/nonnull.cc b/libstdc++-v3/testsuite/21_strings/basic_string_view/operations/find/char/nonnull.cc
new file mode 100644 (file)
index 0000000..69f1850
--- /dev/null
+++ b/libstdc++-v3/testsuite/21_strings/basic_string_view/operations/find/char/nonnull.cc
@@ -0,0 +1,33 @@
+// Copyright (C) 2018 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+// { dg-options "-std=gnu++17 -Wnonnull" }
+// { dg-do compile { target c++17 } }
+
+#include <string_view>
+
+int
+test01()
+{
+  std::string_view s = "abcd";
+  return s.find((const char*)nullptr);         // { dg-warning "null arg" }
+  return s.find((const char*)nullptr, 1);      // { dg-warning "null arg" }
+  return s.find_first_of((const char*)nullptr);        // { dg-warning "null arg" }
+  return s.find_first_of((const char*)nullptr, 1); // { dg-warning "null arg" }
+  return s.find_first_not_of((const char*)nullptr); // { dg-warning "null arg" }
+  return s.find_first_not_of((const char*)nullptr, 1); // { dg-warning "null arg" }
+}

diff --git a/libstdc++-v3/testsuite/21_strings/basic_string_view/operations/rfind/char/nonnull.cc b/libstdc++-v3/testsuite/21_strings/basic_string_view/operations/rfind/char/nonnull.cc
new file mode 100644 (file)
index 0000000..ca8527a
--- /dev/null
+++ b/libstdc++-v3/testsuite/21_strings/basic_string_view/operations/rfind/char/nonnull.cc
@@ -0,0 +1,29 @@
+// Copyright (C) 2018 Free Software Foundation, Inc.
+//
+// This file is part of the GNU ISO C++ Library.  This library is free
+// software; you can redistribute it and/or modify it under the
+// terms of the GNU General Public License as published by the
+// Free Software Foundation; either version 3, or (at your option)
+// any later version.
+
+// This library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+
+// You should have received a copy of the GNU General Public License along
+// with this library; see the file COPYING3.  If not see
+// <http://www.gnu.org/licenses/>.
+
+// { dg-options "-std=gnu++17 -Wnonnull" }
+// { dg-do compile { target c++17 } }
+
+#include <string_view>
+
+int
+test01()
+{
+  std::string_view s = "abcd";
+  return s.rfind((const char*)nullptr);                // { dg-warning "null arg" }
+  return s.rfind((const char*)nullptr, 1);     // { dg-warning "null arg" }
+}