PR libstdc++/85818 ensure path::preferred_separator is defined

Message ID 20180517153618.GA14041@redhat.com
State New
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  • PR libstdc++/85818 ensure path::preferred_separator is defined
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Commit Message

Jonathan Wakely May 17, 2018, 3:36 p.m.
Because path.cc is compiled with -std=gnu++17 the static constexpr
data member is implicitly 'inline' and so no definition gets emitted
unless it gets used in that translation unit. Other translation units
built as C++11 or C++14 still require a namespace-scope definition of
the variable, so mark the definition as used.

	PR libstdc++/85818
	* src/filesystem/path.cc (path::preferred_separator): Add used
	attribute.
	* testsuite/experimental/filesystem/path/preferred_separator.cc: New.

Tested powerpc64le-linux, committed to trunk. Backport to gcc-8 to
follow.
commit e80e2abad41faf6bd62bd1f08baa86f71714811e
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Thu May 17 13:59:00 2018 +0100

    PR libstdc++/85818 ensure path::preferred_separator is defined
    
    Because path.cc is compiled with -std=gnu++17 the static constexpr
    data member is implicitly 'inline' and so no definition gets emitted
    unless it gets used in that translation unit. Other translation units
    built as C++11 or C++14 still require a namespace-scope definition of
    the variable, so mark the definition as used.
    
            PR libstdc++/85818
            * src/filesystem/path.cc (path::preferred_separator): Add used
            attribute.
            * testsuite/experimental/filesystem/path/preferred_separator.cc: New.

Comments

Jonathan Wakely May 21, 2018, 12:29 p.m. | #1
On 17/05/18 16:36 +0100, Jonathan Wakely wrote:
>Because path.cc is compiled with -std=gnu++17 the static constexpr
>data member is implicitly 'inline' and so no definition gets emitted
>unless it gets used in that translation unit. Other translation units
>built as C++11 or C++14 still require a namespace-scope definition of
>the variable, so mark the definition as used.
>
>	PR libstdc++/85818
>	* src/filesystem/path.cc (path::preferred_separator): Add used
>	attribute.
>	* testsuite/experimental/filesystem/path/preferred_separator.cc: New.
>
>Tested powerpc64le-linux, committed to trunk. Backport to gcc-8 to
>follow.

I forgot to make the new test depend on the Filesystem lib being
supported. Fixed by this patch, committed to trunk and gcc-8-branch.
commit 3eb1acc290b7b7407a24b62a3d267f344e88ffbd
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Mon May 21 13:23:30 2018 +0100

    PR libstdc++/85818 make new test require Filesystem support
    
            PR libstdc++/85818
            * testsuite/experimental/filesystem/path/preferred_separator.cc: Add
            dg-require-filesystem-ts.

diff --git a/libstdc++-v3/testsuite/experimental/filesystem/path/preferred_separator.cc b/libstdc++-v3/testsuite/experimental/filesystem/path/preferred_separator.cc
index b470e312bb1..5ca948dfaef 100644
--- a/libstdc++-v3/testsuite/experimental/filesystem/path/preferred_separator.cc
+++ b/libstdc++-v3/testsuite/experimental/filesystem/path/preferred_separator.cc
@@ -17,6 +17,7 @@
 
 // { dg-options "-O0 -lstdc++fs -std=gnu++11" }
 // { dg-do link { target c++11 } }
+// { dg-require-filesystem-ts "" }
 
 #include <experimental/filesystem>

Patch

diff --git a/libstdc++-v3/src/filesystem/path.cc b/libstdc++-v3/src/filesystem/path.cc
index 4d84168d742..899d94e0067 100644
--- a/libstdc++-v3/src/filesystem/path.cc
+++ b/libstdc++-v3/src/filesystem/path.cc
@@ -33,7 +33,7 @@  using fs::path;
 
 fs::filesystem_error::~filesystem_error() = default;
 
-constexpr path::value_type path::preferred_separator;
+constexpr path::value_type path::preferred_separator [[gnu::used]];
 
 path&
 path::remove_filename()
diff --git a/libstdc++-v3/testsuite/experimental/filesystem/path/preferred_separator.cc b/libstdc++-v3/testsuite/experimental/filesystem/path/preferred_separator.cc
new file mode 100644
index 00000000000..b470e312bb1
--- /dev/null
+++ b/libstdc++-v3/testsuite/experimental/filesystem/path/preferred_separator.cc
@@ -0,0 +1,34 @@ 
+// 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 "-O0 -lstdc++fs -std=gnu++11" }
+// { dg-do link { target c++11 } }
+
+#include <experimental/filesystem>
+
+std::experimental::filesystem::path::value_type
+test01()
+{
+  auto* sep = &std::experimental::filesystem::path::preferred_separator;
+  return *sep;
+}
+
+int
+main()
+{
+  test01();
+}