[libc++] Implement LWG4023 (#87513)

ldionne · web-flow · commit ed962a66c5a2 · 2024-04-25T09:32:35.000-04:00
This patch implements LWG4023 by adding explicit assertions for the
added preconditions and also fixes a few tests that were violating these
preconditions.
diff --git a/libcxx/docs/Status/Cxx2cIssues.csv b/libcxx/docs/Status/Cxx2cIssues.csv
@@ -49,7 +49,7 @@
 "`4012 <https://wg21.link/LWG4012>`__","``common_view::begin/end`` are missing the ``simple-view`` check","Tokyo March 2024","","","|ranges|"
 "`4013 <https://wg21.link/LWG4013>`__","``lazy_split_view::outer-iterator::value_type`` should not provide default constructor","Tokyo March 2024","","","|ranges|"
 "`4016 <https://wg21.link/LWG4016>`__","container-insertable checks do not match what container-inserter does","Tokyo March 2024","","",""
-"`4023 <https://wg21.link/LWG4023>`__","Preconditions of ``std::basic_streambuf::setg/setp``","Tokyo March 2024","","",""
+"`4023 <https://wg21.link/LWG4023>`__","Preconditions of ``std::basic_streambuf::setg/setp``","Tokyo March 2024","|Complete|","19.0",""
 "`4025 <https://wg21.link/LWG4025>`__","Move assignment operator of ``std::expected<cv void, E>`` should not be conditionally deleted","Tokyo March 2024","","",""
 "`4030 <https://wg21.link/LWG4030>`__","Clarify whether arithmetic expressions in ``[numeric.sat.func]`` are mathematical or C++","Tokyo March 2024","|Nothing To Do|","",""
 "`4031 <https://wg21.link/LWG4031>`__","``bad_expected_access<void>`` member functions should be ``noexcept``","Tokyo March 2024","|Complete|","16.0",""
diff --git a/libcxx/include/streambuf b/libcxx/include/streambuf
@@ -107,10 +107,12 @@ protected:
 
 */
 
+#include <__assert>
 #include <__config>
 #include <__fwd/streambuf.h>
 #include <__locale>
 #include <__type_traits/is_same.h>
+#include <__utility/is_valid_range.h>
 #include <climits>
 #include <ios>
 #include <iosfwd>
@@ -234,6 +236,9 @@ protected:
   inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1 void gbump(int __n) { __ninp_ += __n; }
 
   inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1 void setg(char_type* __gbeg, char_type* __gnext, char_type* __gend) {
+    _LIBCPP_ASSERT_VALID_INPUT_RANGE(std::__is_valid_range(__gbeg, __gnext), "[gbeg, gnext) must be a valid range");
+    _LIBCPP_ASSERT_VALID_INPUT_RANGE(std::__is_valid_range(__gbeg, __gend), "[gbeg, gend) must be a valid range");
+    _LIBCPP_ASSERT_VALID_INPUT_RANGE(std::__is_valid_range(__gnext, __gend), "[gnext, gend) must be a valid range");
     __binp_ = __gbeg;
     __ninp_ = __gnext;
     __einp_ = __gend;
@@ -249,6 +254,7 @@ protected:
   _LIBCPP_HIDE_FROM_ABI void __pbump(streamsize __n) { __nout_ += __n; }
 
   inline _LIBCPP_HIDE_FROM_ABI_AFTER_V1 void setp(char_type* __pbeg, char_type* __pend) {
+    _LIBCPP_ASSERT_VALID_INPUT_RANGE(std::__is_valid_range(__pbeg, __pend), "[pbeg, pend) must be a valid range");
     __bout_ = __nout_ = __pbeg;
     __eout_           = __pend;
   }
diff --git a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.cons/copy.pass.cpp b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.cons/copy.pass.cpp
@@ -57,18 +57,20 @@ int main(int, char**)
         test<char> t2 = t;
     }
     {
-        char g1, g2, g3, p1, p3;
+        char g[3];
+        char p[3];
         test<char> t;
-        t.setg(&g1, &g2, &g3);
-        t.setp(&p1, &p3);
+        t.setg(&g[0], &g[1], &g[2]);
+        t.setp(&p[0], &p[2]);
         test<char> t2 = t;
     }
 #ifndef TEST_HAS_NO_WIDE_CHARACTERS
     {
-        wchar_t g1, g2, g3, p1, p3;
+        wchar_t g[3];
+        wchar_t p[3];
         test<wchar_t> t;
-        t.setg(&g1, &g2, &g3);
-        t.setp(&p1, &p3);
+        t.setg(&g[0], &g[1], &g[2]);
+        t.setp(&p[0], &p[2]);
         test<wchar_t> t2 = t;
     }
     {
diff --git a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.protected/streambuf.assign/assign.pass.cpp b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.protected/streambuf.assign/assign.pass.cpp
@@ -59,10 +59,11 @@ int main(int, char**)
         t2 = t;
     }
     {
-        char g1, g2, g3, p1, p3;
+        char g[3];
+        char p[3];
         test<char> t;
-        t.setg(&g1, &g2, &g3);
-        t.setp(&p1, &p3);
+        t.setg(&g[0], &g[1], &g[2]);
+        t.setp(&p[0], &p[2]);
         test<char> t2;
         t2 = t;
     }
@@ -73,10 +74,11 @@ int main(int, char**)
         t2 = t;
     }
     {
-        wchar_t g1, g2, g3, p1, p3;
+        wchar_t g[3];
+        wchar_t p[3];
         test<wchar_t> t;
-        t.setg(&g1, &g2, &g3);
-        t.setp(&p1, &p3);
+        t.setg(&g[0], &g[1], &g[2]);
+        t.setp(&p[0], &p[2]);
         test<wchar_t> t2;
         t2 = t;
     }
diff --git a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.protected/streambuf.assign/swap.pass.cpp b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.protected/streambuf.assign/swap.pass.cpp
@@ -68,10 +68,11 @@ int main(int, char**)
         t2.swap(t);
     }
     {
-        char g1, g2, g3, p1, p3;
+        char g[3];
+        char p[3];
         test<char> t;
-        t.setg(&g1, &g2, &g3);
-        t.setp(&p1, &p3);
+        t.setg(&g[0], &g[1], &g[2]);
+        t.setp(&p[0], &p[2]);
         test<char> t2;
         t2.swap(t);
     }
@@ -82,10 +83,11 @@ int main(int, char**)
         t2.swap(t);
     }
     {
-        wchar_t g1, g2, g3, p1, p3;
+        wchar_t g[3];
+        wchar_t p[3];
         test<wchar_t> t;
-        t.setg(&g1, &g2, &g3);
-        t.setp(&p1, &p3);
+        t.setg(&g[0], &g[1], &g[2]);
+        t.setp(&p[0], &p[2]);
         test<wchar_t> t2;
         t2.swap(t);
     }
diff --git a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.protected/streambuf.get.area/setg.assert.pass.cpp b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.protected/streambuf.get.area/setg.assert.pass.cpp
@@ -0,0 +1,68 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// REQUIRES: has-unix-headers
+// UNSUPPORTED: libcpp-hardening-mode=none
+// XFAIL: libcpp-hardening-mode=debug && availability-verbose_abort-missing
+
+// <streambuf>
+
+// template <class charT, class traits = char_traits<charT> >
+// class basic_streambuf;
+
+// void setg(char_type* gbeg, char_type* gnext, char_type* gend);
+
+#include <algorithm>
+#include <iterator>
+#include <streambuf>
+#include <string>
+
+#include "check_assertion.h"
+#include "make_string.h"
+#include "test_macros.h"
+
+template <class CharT>
+struct streambuf : public std::basic_streambuf<CharT> {
+  typedef std::basic_streambuf<CharT> base;
+
+  streambuf() {}
+
+  void setg(CharT* gbeg, CharT* gnext, CharT* gend) { base::setg(gbeg, gnext, gend); }
+};
+
+template <class CharT>
+void test() {
+  std::basic_string<CharT> str = MAKE_STRING(CharT, "ABCDEF");
+  CharT arr[6];
+  std::copy(str.begin(), str.end(), arr);
+
+  {
+    streambuf<CharT> buff;
+    TEST_LIBCPP_ASSERT_FAILURE(
+        buff.setg(std::begin(arr) + 1, std::begin(arr), std::end(arr)), "[gbeg, gnext) must be a valid range");
+  }
+  {
+    streambuf<CharT> buff;
+    TEST_LIBCPP_ASSERT_FAILURE(
+        buff.setg(std::begin(arr) + 1, std::begin(arr) + 1, std::begin(arr)), "[gbeg, gend) must be a valid range");
+  }
+  {
+    streambuf<CharT> buff;
+    TEST_LIBCPP_ASSERT_FAILURE(
+        buff.setg(std::begin(arr), std::begin(arr) + 3, std::begin(arr) + 2), "[gnext, gend) must be a valid range");
+  }
+}
+
+int main(int, char**) {
+  test<char>();
+#ifndef TEST_HAS_NO_WIDE_CHARACTERS
+  test<wchar_t>();
+#endif
+
+  return 0;
+}
diff --git a/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.protected/streambuf.put.area/setp.assert.pass.cpp b/libcxx/test/std/input.output/stream.buffers/streambuf/streambuf.protected/streambuf.put.area/setp.assert.pass.cpp
@@ -0,0 +1,57 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+// REQUIRES: has-unix-headers
+// UNSUPPORTED: libcpp-hardening-mode=none
+// XFAIL: libcpp-hardening-mode=debug && availability-verbose_abort-missing
+
+// <streambuf>
+
+// template <class charT, class traits = char_traits<charT> >
+// class basic_streambuf;
+
+// void setp(char_type* pbeg, char_type* pend);
+
+#include <algorithm>
+#include <iterator>
+#include <streambuf>
+#include <string>
+
+#include "check_assertion.h"
+#include "make_string.h"
+#include "test_macros.h"
+
+template <class CharT>
+struct streambuf : public std::basic_streambuf<CharT> {
+  typedef std::basic_streambuf<CharT> base;
+
+  streambuf() {}
+
+  void setp(CharT* pbeg, CharT* pend) { base::setp(pbeg, pend); }
+};
+
+template <class CharT>
+void test() {
+  std::basic_string<CharT> str = MAKE_STRING(CharT, "ABCDEF");
+  CharT arr[6];
+  std::copy(str.begin(), str.end(), arr);
+
+  {
+    streambuf<CharT> buff;
+    TEST_LIBCPP_ASSERT_FAILURE(buff.setp(std::begin(arr) + 3, std::begin(arr)), "[pbeg, pend) must be a valid range");
+  }
+}
+
+int main(int, char**) {
+  test<char>();
+#ifndef TEST_HAS_NO_WIDE_CHARACTERS
+  test<wchar_t>();
+#endif
+
+  return 0;
+}

Original file line number	Diff line number	Diff line change
`@@ -57,18 +57,20 @@ int main(int, char**)`
`57`	`57`	`test<char> t2 = t;`
`58`	`58`	`}`
`59`	`59`	`{`
`60`		`- char g1, g2, g3, p1, p3;`
	`60`	`+ char g[3];`
	`61`	`+ char p[3];`
`61`	`62`	`test<char> t;`
`62`		`- t.setg(&g1, &g2, &g3);`
`63`		`- t.setp(&p1, &p3);`
	`63`	`+ t.setg(&g[0], &g[1], &g[2]);`
	`64`	`+ t.setp(&p[0], &p[2]);`
`64`	`65`	`test<char> t2 = t;`
`65`	`66`	`}`
`66`	`67`	`#ifndef TEST_HAS_NO_WIDE_CHARACTERS`
`67`	`68`	`{`
`68`		`- wchar_t g1, g2, g3, p1, p3;`
	`69`	`+ wchar_t g[3];`
	`70`	`+ wchar_t p[3];`
`69`	`71`	`test<wchar_t> t;`
`70`		`- t.setg(&g1, &g2, &g3);`
`71`		`- t.setp(&p1, &p3);`
	`72`	`+ t.setg(&g[0], &g[1], &g[2]);`
	`73`	`+ t.setp(&p[0], &p[2]);`
`72`	`74`	`test<wchar_t> t2 = t;`
`73`	`75`	`}`
`74`	`76`	`{`
Original file line number	Diff line number	Diff line change
`@@ -59,10 +59,11 @@ int main(int, char**)`
`59`	`59`	`t2 = t;`
`60`	`60`	`}`
`61`	`61`	`{`
`62`		`- char g1, g2, g3, p1, p3;`
	`62`	`+ char g[3];`
	`63`	`+ char p[3];`
`63`	`64`	`test<char> t;`
`64`		`- t.setg(&g1, &g2, &g3);`
`65`		`- t.setp(&p1, &p3);`
	`65`	`+ t.setg(&g[0], &g[1], &g[2]);`
	`66`	`+ t.setp(&p[0], &p[2]);`
`66`	`67`	`test<char> t2;`
`67`	`68`	`t2 = t;`
`68`	`69`	`}`
`@@ -73,10 +74,11 @@ int main(int, char**)`
`73`	`74`	`t2 = t;`
`74`	`75`	`}`
`75`	`76`	`{`
`76`		`- wchar_t g1, g2, g3, p1, p3;`
	`77`	`+ wchar_t g[3];`
	`78`	`+ wchar_t p[3];`
`77`	`79`	`test<wchar_t> t;`
`78`		`- t.setg(&g1, &g2, &g3);`
`79`		`- t.setp(&p1, &p3);`
	`80`	`+ t.setg(&g[0], &g[1], &g[2]);`
	`81`	`+ t.setp(&p[0], &p[2]);`
`80`	`82`	`test<wchar_t> t2;`
`81`	`83`	`t2 = t;`
`82`	`84`	`}`
Original file line number	Diff line number	Diff line change
`@@ -68,10 +68,11 @@ int main(int, char**)`
`68`	`68`	`t2.swap(t);`
`69`	`69`	`}`
`70`	`70`	`{`
`71`		`- char g1, g2, g3, p1, p3;`
	`71`	`+ char g[3];`
	`72`	`+ char p[3];`
`72`	`73`	`test<char> t;`
`73`		`- t.setg(&g1, &g2, &g3);`
`74`		`- t.setp(&p1, &p3);`
	`74`	`+ t.setg(&g[0], &g[1], &g[2]);`
	`75`	`+ t.setp(&p[0], &p[2]);`
`75`	`76`	`test<char> t2;`
`76`	`77`	`t2.swap(t);`
`77`	`78`	`}`
`@@ -82,10 +83,11 @@ int main(int, char**)`
`82`	`83`	`t2.swap(t);`
`83`	`84`	`}`
`84`	`85`	`{`
`85`		`- wchar_t g1, g2, g3, p1, p3;`
	`86`	`+ wchar_t g[3];`
	`87`	`+ wchar_t p[3];`
`86`	`88`	`test<wchar_t> t;`
`87`		`- t.setg(&g1, &g2, &g3);`
`88`		`- t.setp(&p1, &p3);`
	`89`	`+ t.setg(&g[0], &g[1], &g[2]);`
	`90`	`+ t.setp(&p[0], &p[2]);`
`89`	`91`	`test<wchar_t> t2;`
`90`	`92`	`t2.swap(t);`
`91`	`93`	`}`