Add patch for PR libstdc++/86138

2 files changed, 185 insertions, 1 deletions

diff --git a/cygwin-gcc.spec b/cygwin-gcc.spec
index 0bc75ad..2fa7d12 100644
--- a/cygwin-gcc.spec
+++ b/cygwin-gcc.spec
@@ -3,7 +3,7 @@
 %global gcc_version 7.3.0
 # Note, gcc_release must be integer, if you want to add suffixes to
 # %%{release}, append them after %%{gcc_release} on Release: line.
-%global gcc_release 1
+%global gcc_release 2
 
 %global build_ada 0
 %global build_objc 0
@@ -75,6 +75,9 @@ Patch31:        0031-define_std-unix.patch
 Patch1000:      1000-cross-exe-suffix.patch
 Patch1001:      1001-textdomain.patch
 
+# Upstream patches
+Patch2000:      pr86138.patch
+
 %description
 Cygwin cross-compiler (GCC) suite.
 
@@ -320,6 +323,8 @@ Cygwin x86_64 cross-compiler for Ada.
 %patch1000 -p1
 %patch1001 -p1
 
+%patch2000 -p1
+
 echo %{gcc_version} > gcc/BASE-VER
 echo 'Fedora Cygwin %{gcc_version}-%{gcc_release}' > gcc/DEV-PHASE
 
@@ -747,6 +752,9 @@ cat cygwin-cpplib.lang >> cygwin-gcc.lang
 
 
 %changelog
+* Thu Jul 12 2018 Yaakov Selkowitz <yselkowi@redhat.com> - 7.3.0-2
+- Add patch for PR libstdc++/86138
+
 * Tue Jun 05 2018 Yaakov Selkowitz <yselkowi@redhat.com> - 7.3.0-1
 - new version
 - Enable libstdc++ Filesystem TS
diff --git a/pr86138.patch b/pr86138.patch
new file mode 100644
index 0000000..a84e0e7
--- /dev/null
+++ b/pr86138.patch
@@ -0,0 +1,176 @@
+From 2cca047791a52015d63fd42e9791ed7dc237099d Mon Sep 17 00:00:00 2001
+From: redi <redi@138bc75d-0d04-0410-961f-82ee72b054a4>
+Date: Fri, 22 Jun 2018 15:58:38 +0000
+Subject: [PATCH] PR libstdc++/86138 prevent implicit instantiation of COW
+ empty rep
+
+The explicit instantiation declarations for std::basic_string are
+disabled for C++17 (and later) so that basic_string symbols get
+implicitly instantiated in every translation unit that needs them.  On
+targets that don't support STB_GNU_UNIQUE this leads to multiple copies
+of the empty rep symbol for COW strings. In order to detect whether a
+COW string needs to deallocate its storage it compares the address with
+the empty rep.  When there are multiple copies of the empty rep object
+the address is not unique, and so string destructors try to delete the
+empty rep, which crashes.
+
+In order to guarantee uniqueness of the _S_empty_rep_storage symbol this
+patch adds an explicit instantiation declaration for just that symbol.
+This means the other symbols are still implicitly instantiated in C++17
+code, but for the empty rep the definition in the library gets used.
+
+Separately, there is no need for C++17 code to implicitly instantiate
+the I/O functions for strings, so this also restores the explicit
+instantiation declarations for those functions.
+
+Backport from mainline
+2018-06-22  Jonathan Wakely  <jwakely@redhat.com>
+
+	PR libstdc++/86138
+	* include/bits/basic_string.tcc:
+	[__cplusplus > 201402 && !_GLIBCXX_USE_CXX11_ABI]
+	(basic_string<char>::_Rep::_S_empty_rep_storage)
+	(basic_string<wchar_t>::_Rep::_S_empty_rep_storage): Add explicit
+	instantiation declarations.
+	[__cplusplus > 201402] (operator>>, operator<<, getline): Re-enable
+	explicit instantiation declarations.
+	* testsuite/21_strings/basic_string/cons/char/86138.cc: New.
+	* testsuite/21_strings/basic_string/cons/wchar_t/86138.cc: New.
+
+git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/branches/gcc-7-branch@261907 138bc75d-0d04-0410-961f-82ee72b054a4
+---
+ libstdc++-v3/ChangeLog                        | 16 ++++++++++
+ libstdc++-v3/include/bits/basic_string.tcc    | 25 ++++++++++++++--
+ .../basic_string/cons/char/86138.cc           | 30 +++++++++++++++++++
+ .../basic_string/cons/wchar_t/86138.cc        | 30 +++++++++++++++++++
+ 4 files changed, 98 insertions(+), 3 deletions(-)
+ create mode 100644 libstdc++-v3/testsuite/21_strings/basic_string/cons/char/86138.cc
+ create mode 100644 libstdc++-v3/testsuite/21_strings/basic_string/cons/wchar_t/86138.cc
+
+diff --git a/libstdc++-v3/include/bits/basic_string.tcc b/libstdc++-v3/include/bits/basic_string.tcc
+index 41b7fa196b0..d185a54aaf0 100644
+--- a/libstdc++-v3/include/bits/basic_string.tcc
++++ b/libstdc++-v3/include/bits/basic_string.tcc
+@@ -1597,8 +1597,21 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
+ 
+   // Inhibit implicit instantiations for required instantiations,
+   // which are defined via explicit instantiations elsewhere.
+-#if _GLIBCXX_EXTERN_TEMPLATE > 0 && __cplusplus <= 201402L
++#if _GLIBCXX_EXTERN_TEMPLATE > 0
++  // The explicit instantiations definitions in src/c++11/string-inst.cc
++  // are compiled as C++14, so the new C++17 members aren't instantiated.
++  // Until those definitions are compiled as C++17 suppress the declaration,
++  // so C++17 code will implicitly instantiate std::string and std::wstring
++  // as needed.
++# if __cplusplus <= 201402L
+   extern template class basic_string<char>;
++# elif ! _GLIBCXX_USE_CXX11_ABI
++  // Still need to prevent implicit instantiation of the COW empty rep,
++  // to ensure the definition in libstdc++.so is unique (PR 86138).
++  extern template basic_string<char>::size_type
++    basic_string<char>::_Rep::_S_empty_rep_storage[];
++# endif
++
+   extern template
+     basic_istream<char>&
+     operator>>(basic_istream<char>&, string&);
+@@ -1613,7 +1626,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
+     getline(basic_istream<char>&, string&);
+ 
+ #ifdef _GLIBCXX_USE_WCHAR_T
++# if __cplusplus <= 201402L
+   extern template class basic_string<wchar_t>;
++# elif ! _GLIBCXX_USE_CXX11_ABI
++  extern template basic_string<wchar_t>::size_type
++    basic_string<wchar_t>::_Rep::_S_empty_rep_storage[];
++# endif
++
+   extern template
+     basic_istream<wchar_t>&
+     operator>>(basic_istream<wchar_t>&, wstring&);
+@@ -1626,8 +1645,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
+   extern template
+     basic_istream<wchar_t>&
+     getline(basic_istream<wchar_t>&, wstring&);
+-#endif
+-#endif
++#endif // _GLIBCXX_USE_WCHAR_T
++#endif // _GLIBCXX_EXTERN_TEMPLATE > 0
+ 
+ _GLIBCXX_END_NAMESPACE_VERSION
+ } // namespace std
+diff --git a/libstdc++-v3/testsuite/21_strings/basic_string/cons/char/86138.cc b/libstdc++-v3/testsuite/21_strings/basic_string/cons/char/86138.cc
+new file mode 100644
+index 00000000000..a85fd9c82c9
+--- /dev/null
++++ b/libstdc++-v3/testsuite/21_strings/basic_string/cons/char/86138.cc
+@@ -0,0 +1,30 @@
++// 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" }
++// { dg-do compile { target c++1z } }
++// { dg-final { scan-assembler-not "_ZNSs4_Rep20_S_empty_rep_storageE:" } }
++
++#undef _GLIBCXX_USE_CXX11_ABI
++#define _GLIBCXX_USE_CXX11_ABI 0
++#include <string>
++
++void
++test01(std::string* s)
++{
++  s->~basic_string();
++}
+diff --git a/libstdc++-v3/testsuite/21_strings/basic_string/cons/wchar_t/86138.cc b/libstdc++-v3/testsuite/21_strings/basic_string/cons/wchar_t/86138.cc
+new file mode 100644
+index 00000000000..d77922976d0
+--- /dev/null
++++ b/libstdc++-v3/testsuite/21_strings/basic_string/cons/wchar_t/86138.cc
+@@ -0,0 +1,30 @@
++// 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" }
++// { dg-do compile { target c++1z } }
++// { dg-final { scan-assembler-not "_ZNSbIwSt11char_traitsIwESaIwEE4_Rep20_S_empty_rep_storageE:" } }
++
++#undef _GLIBCXX_USE_CXX11_ABI
++#define _GLIBCXX_USE_CXX11_ABI 0
++#include <string>
++
++void
++test01(std::wstring* s)
++{
++  s->~basic_string();
++}
+-- 
+2.18.0
+