Re: [ PATCH ] [ C++ ] [ libstdc++ ] P1208r6 Merge source_location

[Jonathan Wakely <jwakely@redhat.com>]

[-- Attachment #1: Type: text/plain, Size: 979 bytes --]

On 02/01/20 17:20 -0500, JeanHeyd Meneide wrote:
>On Thu, Jan 2, 2020 at 5:07 PM Jakub Jelinek <jakub@redhat.com> wrote:
>>
>> On Thu, Jan 02, 2020 at 04:57:01PM -0500, JeanHeyd Meneide wrote:
>> > +#if defined(_GLIBCXX_HAVE_BUILTIN_SOURCE_LOCATION)
>> > +# define __cpp_lib_source_location 201907L
>> > +#elif defined(_GLIBCXX_HAVE_BUILTIN_LINE) && defined(_GLIBCXX_HAVE_BUILTIN_COLUMN)
>> > +# define __cpp_lib_is_constant_evaluated 201907L
>>
>> How is __cpp_lib_is_constant_evaluated related to presence of __builtin_LINE
>> and __builtin_COLUMN?
>
>Oops. Sorry; fat-fingered the diff a little!

I've committed a slightly reworked version of JeanHeyd's
<source_location> patch (see attached). Jakub has improved the
built-in so all the commented out tests work now. There's one more
compiler patch coming to use __PRETTY_FUNCTION__ for the function
name, so I'll tweak the new tests after than has gone in.

Tested powerpc64le-linux, committed to trunk.

Thanks, JeanHeyd!



[-- Attachment #2: patch.txt --]
[-- Type: text/x-patch, Size: 20089 bytes --]

commit 57d76ee9cf6265e012fad6286adfaeaba9414c11
Author: JeanHeyd Meneide <phdofthehouse@gmail.com>
Date:   Thu Dec 3 19:17:13 2020

    libtdc++: Define std::source_location for C++20
    
    This doesn't define a new _GLIBCXX_HAVE_BUILTIN_SOURCE_LOCATION macro.
    because using __has_builtin(__builtin_source_location) is sufficient.
    Currently only GCC supports it, but if/when Clang and Intel add it the
    __has_builtin check should for them too.
    
    Co-authored-by: Jonathan Wakely <jwakely@redhat.com>
    
    libstdc++-v3/ChangeLog:
    
            * doc/doxygen/user.cfg.in (INPUT): Add <source_location>.
            * include/Makefile.am: Add <source_location>.
            * include/Makefile.in: Regenerate.
            * include/std/version (__cpp_lib_source_location): Define.
            * include/std/source_location: New file.
            * testsuite/18_support/source_location/1.cc: New test.
            * testsuite/18_support/source_location/consteval.cc: New test.
            * testsuite/18_support/source_location/srcloc.h: New test.
            * testsuite/18_support/source_location/version.cc: New test.

diff --git a/libstdc++-v3/doc/doxygen/user.cfg.in b/libstdc++-v3/doc/doxygen/user.cfg.in
index 1966055e675..2261d572efb 100644
--- a/libstdc++-v3/doc/doxygen/user.cfg.in
+++ b/libstdc++-v3/doc/doxygen/user.cfg.in
@@ -891,6 +891,7 @@ INPUT                  = @srcdir@/doc/doxygen/doxygroups.cc \
                          include/semaphore \
                          include/set \
                          include/shared_mutex \
+                         include/source_location \
                          include/span \
                          include/sstream \
                          include/stack \
diff --git a/libstdc++-v3/include/Makefile.am b/libstdc++-v3/include/Makefile.am
index ca413b8fdfe..9dbc7dcb32d 100644
--- a/libstdc++-v3/include/Makefile.am
+++ b/libstdc++-v3/include/Makefile.am
@@ -73,6 +73,7 @@ std_headers = \
 	${std_srcdir}/semaphore \
 	${std_srcdir}/set \
 	${std_srcdir}/shared_mutex \
+	${std_srcdir}/source_location \
 	${std_srcdir}/span \
 	${std_srcdir}/sstream \
 	${std_srcdir}/syncstream \
diff --git a/libstdc++-v3/include/std/source_location b/libstdc++-v3/include/std/source_location
new file mode 100644
index 00000000000..13d4bd48857
--- /dev/null
+++ b/libstdc++-v3/include/std/source_location
@@ -0,0 +1,92 @@
+// <source_location> -*- C++ -*-
+
+// Copyright (C) 2020 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.
+
+// Under Section 7 of GPL version 3, you are granted additional
+// permissions described in the GCC Runtime Library Exception, version
+// 3.1, as published by the Free Software Foundation.
+
+// You should have received a copy of the GNU General Public License and
+// a copy of the GCC Runtime Library Exception along with this program;
+// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+// <http://www.gnu.org/licenses/>.
+
+/** @file include/source_location
+ *  This is a Standard C++ Library header.
+ */
+
+#ifndef _GLIBCXX_SRCLOC
+#define _GLIBCXX_SRCLOC 1
+
+#if __cplusplus > 201703L && __has_builtin(__builtin_source_location)
+#include <bits/c++config.h>
+
+namespace std
+{
+_GLIBCXX_BEGIN_NAMESPACE_VERSION
+
+#define __cpp_lib_source_location 201907L
+
+  /// A class that describes a location in source code.
+  struct source_location
+  {
+  private:
+    using uint_least32_t = __UINT_LEAST32_TYPE__;
+
+  public:
+
+    // [support.srcloc.cons], creation
+    static consteval source_location
+    current(const void* __p = __builtin_source_location()) noexcept
+    {
+      source_location __ret;
+      __ret._M_impl = static_cast <const __impl*>(__p);
+      return __ret;
+    }
+
+    constexpr source_location() noexcept { }
+
+    // [support.srcloc.obs], observers
+    constexpr uint_least32_t
+    line() const noexcept
+    { return _M_impl ? _M_impl->_M_line : 0u; }
+
+    constexpr uint_least32_t
+    column() const noexcept
+    { return _M_impl ? _M_impl->_M_column : 0u; }
+
+    constexpr const char*
+    file_name() const noexcept
+    { return _M_impl ? _M_impl->_M_file_name : ""; }
+
+    constexpr const char*
+    function_name() const noexcept
+    { return _M_impl ? _M_impl->_M_function_name : ""; }
+
+  private:
+    struct __impl
+    {
+      const char* _M_file_name;
+      const char* _M_function_name;
+      unsigned _M_line;
+      unsigned _M_column;
+    };
+
+    const __impl* _M_impl = nullptr;
+  };
+
+_GLIBCXX_END_NAMESPACE_VERSION
+} // namespace std
+#endif // C++20 && __builtin_source_location
+#endif // _GLIBCXX_SRCLOC
diff --git a/libstdc++-v3/include/std/version b/libstdc++-v3/include/std/version
index 6e4bd99b361..e4a8bed52ab 100644
--- a/libstdc++-v3/include/std/version
+++ b/libstdc++-v3/include/std/version
@@ -238,6 +238,9 @@
 # define __cpp_lib_semaphore 201907L
 #endif
 #define __cpp_lib_shift 201806L
+#if __has_builtin(__builtin_source_location)
+# define __cpp_lib_source_location 201907L
+#endif
 #if __cpp_lib_concepts
 # define __cpp_lib_span 202002L
 #endif
diff --git a/libstdc++-v3/testsuite/18_support/source_location/1.cc b/libstdc++-v3/testsuite/18_support/source_location/1.cc
new file mode 100644
index 00000000000..c945aaa4d97
--- /dev/null
+++ b/libstdc++-v3/testsuite/18_support/source_location/1.cc
@@ -0,0 +1,155 @@
+// Copyright (C) 2020 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/>.
+
+// Example from C++ Standard Working Draft N4842, November 2019 Mailing
+// Adapted for testing.
+
+// { dg-options "-std=gnu++2a -include string -include stdexcept" }
+// { dg-do run { target c++2a } }
+
+#include <source_location>
+
+#ifndef __cpp_lib_source_location
+# error "Feature-test macro for source_location missing in <source_location>"
+#elif __cpp_lib_source_location != 201907L
+# error "Feature-test macro for source_location has wrong value in <source_location>"
+#endif
+
+#include <string_view>
+#include <testsuite_hooks.h>
+#include "srcloc.h"
+
+
+struct s {
+  std::source_location member = std::source_location::current();
+  int other_member = 1;
+
+  s(std::source_location loc = std::source_location::current())
+    : member(loc) // values of member refer to calling function
+  { }
+
+  s(int blather) : // values of member refer to this location
+    other_member(blather)
+  { }
+};
+
+std::source_location
+f(std::source_location a = std::source_location::current());
+
+std::source_location
+f(std::source_location a)
+{ return a; }
+
+auto
+g()
+{
+  struct srcloc_and_line
+  {
+    std::source_location sl;
+    unsigned line;
+  };
+
+  std::source_location c = std::source_location::current();
+  return srcloc_and_line{ f(c), __LINE__ - 1 };
+}
+
+int main ()
+{
+  std::source_location main_sl = std::source_location::current();
+  unsigned main_sl_line = __LINE__ - 1;
+  std::source_location f_arg_sl = f(main_sl);
+  unsigned f_arg_sl_line = main_sl_line;
+  auto [g_sl, g_sl_line] = g();
+  std::source_location f_sl = f();
+  unsigned f_sl_line = __LINE__ - 1;
+  std::source_location h_sl = h(); // defined in ./srcloc.h
+  s member_main_sl(main_sl);
+  s member_defaulted_sl(1);
+  s member_sl = s{};
+  const unsigned member_sl_line = __LINE__ - 1;
+
+  using namespace std::string_view_literals;
+
+  std::string_view main_sl_fn_name(main_sl.function_name());
+  std::string_view main_sl_fi_name(main_sl.file_name());
+  VERIFY(main_sl.line() == main_sl_line);
+  // closing paren of call
+  VERIFY(main_sl.column() == 64);
+  VERIFY(main_sl_fn_name.ends_with("main"sv));
+  VERIFY(main_sl_fi_name.ends_with("1.cc"sv));
+
+  std::string_view f_arg_sl_fn_name(f_arg_sl.function_name());
+  std::string_view f_arg_sl_fi_name(f_arg_sl.file_name());
+  VERIFY(f_arg_sl.line() == f_arg_sl_line);
+  // closing paren of call
+  VERIFY(f_arg_sl.column() == 64);
+  VERIFY(f_arg_sl_fn_name.ends_with("main"sv));
+  VERIFY(f_arg_sl_fi_name.ends_with("1.cc"sv));
+
+  std::string_view g_sl_fn_name(g_sl.function_name());
+  std::string_view g_sl_fi_name(g_sl.file_name());
+  VERIFY(g_sl.line() == g_sl_line);
+  VERIFY(g_sl.column() == 58); // closing paren of call
+  VERIFY(g_sl_fn_name.ends_with("g"sv));
+  VERIFY(g_sl_fi_name.ends_with("1.cc"sv));
+
+  std::string_view h_sl_fn_name(h_sl.function_name());
+  std::string_view h_sl_fi_name(h_sl.file_name());
+  VERIFY(h_sl.line() == 23);
+  VERIFY(h_sl.column() == 58); // closing paren of call
+  VERIFY(h_sl_fn_name.ends_with("h"sv));
+  VERIFY(h_sl_fi_name.ends_with("srcloc.h"sv));
+
+  std::string_view member_main_sl_fn_name(member_main_sl.member.function_name());
+  std::string_view member_main_sl_fi_name(member_main_sl.member.file_name());
+  VERIFY(member_main_sl.member.line() == main_sl_line);
+  VERIFY(member_main_sl.member.column() == 64);
+  VERIFY(member_main_sl_fn_name.ends_with("main"sv));
+  VERIFY(member_main_sl_fi_name.ends_with("1.cc"sv));
+
+  std::string_view member_defaulted_sl_fi_name(
+    member_defaulted_sl.member.file_name());
+  std::string_view member_defaulted_sl_fn_name(
+    member_defaulted_sl.member.function_name());
+  VERIFY(member_defaulted_sl.member.line() == 46);
+  // closing paren of constructor declaration
+  VERIFY(member_defaulted_sl.member.column() == 25);
+#if 0
+  VERIFY(member_defaulted_sl_fn_name.starts_with("s::s(int)"sv));
+#endif
+  VERIFY(member_defaulted_sl_fi_name.ends_with("1.cc"sv));
+
+  std::string_view member_sl_fi_name(
+    member_sl.member.file_name());
+  std::string_view member_sl_fn_name(
+    member_sl.member.function_name());
+  VERIFY(member_sl.member.line() == member_sl_line);
+  // closing brace/paren of constructor
+  VERIFY(member_sl.member.column() == 19);
+  VERIFY(member_sl_fn_name.starts_with("main"sv));
+  VERIFY(member_sl_fi_name.ends_with("1.cc"sv));
+
+  std::string_view f_sl_fi_name(f_sl.file_name());
+  std::string_view f_sl_fn_name(f_sl.function_name());
+  VERIFY(f_sl.line() == f_sl_line);
+  // closing paren of call
+  VERIFY(f_sl.column() == 33);
+  VERIFY(f_sl_fn_name.ends_with("main"sv));
+  VERIFY(f_sl_fi_name.ends_with("1.cc"sv));
+
+  return 0;
+}
diff --git a/libstdc++-v3/testsuite/18_support/source_location/consteval.cc b/libstdc++-v3/testsuite/18_support/source_location/consteval.cc
new file mode 100644
index 00000000000..9b137f8641d
--- /dev/null
+++ b/libstdc++-v3/testsuite/18_support/source_location/consteval.cc
@@ -0,0 +1,149 @@
+// Copyright (C) 2020 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/>.
+
+// Example from C++ Standard Working Draft N4842, November 2019 Mailing
+// Adapted for testing.
+
+// { dg-options "-std=gnu++2a" }
+// { dg-do compile { target c++2a } }
+
+#include <source_location>
+#include <string_view>
+
+struct s {
+  std::source_location member = std::source_location::current();
+  int other_member = 1;
+
+  constexpr s(std::source_location loc = std::source_location::current())
+    : member(loc) // values of member refer to calling function
+  { }
+
+  constexpr s(int blather) : // values of member refer to this location
+    other_member(blather)
+  { }
+};
+
+constexpr std::source_location
+f(std::source_location a = std::source_location::current())
+{ return a; }
+
+constexpr auto
+g()
+{
+  struct srcloc_and_line
+  {
+    std::source_location sl;
+    unsigned line;
+  };
+
+  std::source_location c = std::source_location::current();
+  return srcloc_and_line{ f(c), __LINE__ - 1 };
+}
+
+#include "srcloc.h"
+
+int main ()
+{
+  constexpr std::source_location main_sl = std::source_location::current();
+  constexpr unsigned main_sl_line = __LINE__ - 1;
+  constexpr std::source_location f_arg_sl = f(main_sl);
+  constexpr unsigned f_arg_sl_line = main_sl_line;
+  constexpr std::source_location g_sl = g().sl;
+  constexpr unsigned g_sl_line = g().line;
+  constexpr std::source_location f_sl = f();
+  constexpr unsigned f_sl_line = __LINE__ - 1;
+  constexpr std::source_location h_sl = h(); // defined in ./srcloc.h
+  constexpr s member_main_sl(main_sl);
+  constexpr s member_defaulted_sl(1);
+  constexpr s member_sl = s{};
+  constexpr unsigned member_sl_line = __LINE__ - 1;
+
+  using namespace std::string_view_literals;
+
+  static_assert (std::source_location::current ().line () == __LINE__);
+  static_assert (std::source_location::current ().column () == 49);
+
+
+  constexpr std::string_view main_sl_fn_name(main_sl.function_name());
+  constexpr std::string_view main_sl_fi_name(main_sl.file_name());
+  static_assert(main_sl.line() == main_sl_line);
+  // closing paren of call
+  static_assert(main_sl.column() == 74);
+  static_assert(main_sl_fn_name.ends_with("main"sv));
+  static_assert(main_sl_fi_name.ends_with("consteval.cc"sv));
+
+  constexpr std::string_view f_arg_sl_fn_name(f_arg_sl.function_name());
+  constexpr std::string_view f_arg_sl_fi_name(f_arg_sl.file_name());
+  static_assert(f_arg_sl.line() == f_arg_sl_line);
+  // closing paren of call
+  static_assert(f_arg_sl.column() == 74);
+  static_assert(f_arg_sl_fn_name.ends_with("main"sv));
+  static_assert(f_arg_sl_fi_name.ends_with("consteval.cc"sv));
+
+  constexpr std::string_view g_sl_fn_name(g_sl.function_name());
+  constexpr std::string_view g_sl_fi_name(g_sl.file_name());
+  static_assert(g_sl.line() == g_sl_line);
+  static_assert(g_sl.column() == 58); // closing paren of call
+  static_assert(g_sl_fn_name.ends_with("g"sv));
+  static_assert(g_sl_fi_name.ends_with("consteval.cc"sv));
+
+  constexpr std::string_view h_sl_fn_name(h_sl.function_name());
+  constexpr std::string_view h_sl_fi_name(h_sl.file_name());
+  static_assert(h_sl.line() == 23);
+  static_assert(h_sl.column() == 58); // closing paren of call
+  static_assert(h_sl_fn_name.ends_with("h"sv));
+  static_assert(h_sl_fi_name.ends_with("srcloc.h"sv));
+
+  constexpr std::string_view member_main_sl_fn_name(member_main_sl.member.function_name());
+  constexpr std::string_view member_main_sl_fi_name(member_main_sl.member.file_name());
+  static_assert(member_main_sl.member.line() == main_sl_line);
+  static_assert(member_main_sl.member.column() == 74);
+  static_assert(member_main_sl_fn_name.ends_with("main"sv));
+  static_assert(member_main_sl_fi_name.ends_with("consteval.cc"sv));
+
+  constexpr std::string_view member_defaulted_sl_fi_name(
+    member_defaulted_sl.member.file_name());
+  constexpr std::string_view member_defaulted_sl_fn_name(
+    member_defaulted_sl.member.function_name());
+  static_assert(member_defaulted_sl.member.line() == 36);
+  // closing paren of constructor declaration
+  static_assert(member_defaulted_sl.member.column() == 25);
+#if 0
+  static_assert(member_defaulted_sl_fn_name.ends_with("s::s(int)"sv));
+#endif
+  static_assert(member_defaulted_sl_fi_name.ends_with("consteval.cc"sv));
+
+  constexpr std::string_view member_sl_fi_name(
+    member_sl.member.file_name());
+  constexpr std::string_view member_sl_fn_name(
+    member_sl.member.function_name());
+  static_assert(member_sl.member.line() == member_sl_line);
+  // closing brace/paren of constructor
+  static_assert(member_sl.member.column() == 29);
+  static_assert(member_sl_fn_name.starts_with("main"sv));
+  static_assert(member_sl_fi_name.ends_with("consteval.cc"sv));
+
+  constexpr std::string_view f_sl_fi_name(f_sl.file_name());
+  constexpr std::string_view f_sl_fn_name(f_sl.function_name());
+  static_assert(f_sl.line() == f_sl_line);
+  // closing paren of call
+  static_assert(f_sl.column() == 43);
+  static_assert(f_sl_fn_name.ends_with("main"sv));
+  static_assert(f_sl_fi_name.ends_with("consteval.cc"sv));
+
+  return 0;
+}
diff --git a/libstdc++-v3/testsuite/18_support/source_location/srcloc.h b/libstdc++-v3/testsuite/18_support/source_location/srcloc.h
new file mode 100644
index 00000000000..9b05458ee2f
--- /dev/null
+++ b/libstdc++-v3/testsuite/18_support/source_location/srcloc.h
@@ -0,0 +1,25 @@
+// Copyright (C) 2020 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/>.
+
+#include <source_location>
+
+constexpr std::source_location
+h()
+{
+  std::source_location a = std::source_location::current();
+  return a;
+}
diff --git a/libstdc++-v3/testsuite/18_support/source_location/version.cc b/libstdc++-v3/testsuite/18_support/source_location/version.cc
new file mode 100644
index 00000000000..f2b3bf6fa1e
--- /dev/null
+++ b/libstdc++-v3/testsuite/18_support/source_location/version.cc
@@ -0,0 +1,27 @@
+// Copyright (C) 2020 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++2a" }
+// { dg-do preprocess { target c++2a } }
+
+#include <version>
+
+#ifndef __cpp_lib_source_location
+# error "Feature-test macro for source_location missing in <version>"
+#elif __cpp_lib_source_location != 201907L
+# error "Feature-test macro for source_location has wrong value in <version>"
+#endif