[PATCH] libstdc++: Declare const global variables inline

[Patrick Palka <ppalka@redhat.com>]

IIUC such variables should be declared inline to avoid potential ODR
violations since they're otherwise considered to be distinct (internal
linkage) entities across TUs.

The changes inside the regex_constants and execution namespace seem to
be unimplemented parts of P0607R0; the rest of the changes touch only
implementation details.

Tested on x86_64-pc-linux-gnu, does this look OK for trunk?

libstdc++-v3/ChangeLog:

	* include/bits/atomic_wait.h (_detail::__platform_wait_alignment):
	Declare inline.  Remove redundant static specifier.
	(__detail::__atomic_spin_count_relax): Declare inline.
	(__detail::__atomic_spin_count): Likewise.
	* include/bits/regex_automaton.h (__detail::_S_invalid_state_id):
	Conditionally declare inline.  Declare constexpr.  Remove
	redundant const and static specifiers.
	* include/bits/regex_error.h (regex_constants::error_collate): Conditionally
	declare inline.
	(regex_constants::error_ctype): Likewise.
	(regex_constants::error_escape): Likewise.
	(regex_constants::error_backref): Likewise.
	(regex_constants::error_brack): Likewise.
	(regex_constants::error_paren): Likewise.
	(regex_constants::error_brace): Likewise.
	(regex_constants::error_badbrace): Likewise.
	(regex_constants::error_range): Likewise.
	(regex_constants::error_space): Likewise.
	(regex_constants::error_badrepeat): Likewise.
	(regex_constants::error_complexity): Likewise.
	(regex_constants::error_stack): Likewise.
	* include/ext/concurrence.h (__gnu_cxx::__default_lock_policy):
	Likewise.  Remove redundant static specifier.
	* include/pstl/execution_defs.h (execution::seq): Conditionally declare
	inline.
	(execution::par): Likewise.
	(execution::par_unseq): Likewise.
	(execution::unseq): Likewise.
---
 libstdc++-v3/include/bits/atomic_wait.h     |  8 +++----
 libstdc++-v3/include/bits/regex_automaton.h |  2 +-
 libstdc++-v3/include/bits/regex_error.h     | 26 ++++++++++-----------
 libstdc++-v3/include/ext/concurrence.h      |  2 +-
 libstdc++-v3/include/pstl/execution_defs.h  |  8 +++----
 5 files changed, 23 insertions(+), 23 deletions(-)

diff --git a/libstdc++-v3/include/bits/atomic_wait.h b/libstdc++-v3/include/bits/atomic_wait.h
index 76ed7409937..bd1ed56d157 100644
--- a/libstdc++-v3/include/bits/atomic_wait.h
+++ b/libstdc++-v3/include/bits/atomic_wait.h
@@ -58,14 +58,14 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 #ifdef _GLIBCXX_HAVE_LINUX_FUTEX
 #define _GLIBCXX_HAVE_PLATFORM_WAIT 1
     using __platform_wait_t = int;
-    static constexpr size_t __platform_wait_alignment = 4;
+    inline constexpr size_t __platform_wait_alignment = 4;
 #else
 // define _GLIBCX_HAVE_PLATFORM_WAIT and implement __platform_wait()
 // and __platform_notify() if there is a more efficient primitive supported
 // by the platform (e.g. __ulock_wait()/__ulock_wake()) which is better than
 // a mutex/condvar based wait.
     using __platform_wait_t = uint64_t;
-    static constexpr size_t __platform_wait_alignment
+    inline constexpr size_t __platform_wait_alignment
       = __alignof__(__platform_wait_t);
 #endif
   } // namespace __detail
@@ -142,8 +142,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 #endif
     }
 
-    constexpr auto __atomic_spin_count_relax = 12;
-    constexpr auto __atomic_spin_count = 16;
+    inline constexpr auto __atomic_spin_count_relax = 12;
+    inline constexpr auto __atomic_spin_count = 16;
 
     struct __default_spin_policy
     {
diff --git a/libstdc++-v3/include/bits/regex_automaton.h b/libstdc++-v3/include/bits/regex_automaton.h
index f95eb7dad6d..44bde42e212 100644
--- a/libstdc++-v3/include/bits/regex_automaton.h
+++ b/libstdc++-v3/include/bits/regex_automaton.h
@@ -46,7 +46,7 @@ namespace __detail
    */
 
   typedef long _StateIdT;
-  static const _StateIdT _S_invalid_state_id  = -1;
+  _GLIBCXX17_INLINE constexpr _StateIdT _S_invalid_state_id  = -1;
 
   template<typename _CharT>
     using _Matcher = std::function<bool (_CharT)>;
diff --git a/libstdc++-v3/include/bits/regex_error.h b/libstdc++-v3/include/bits/regex_error.h
index 74a1428c2c7..ab207650d44 100644
--- a/libstdc++-v3/include/bits/regex_error.h
+++ b/libstdc++-v3/include/bits/regex_error.h
@@ -66,60 +66,60 @@ namespace regex_constants
     };
 
   /** The expression contained an invalid collating element name. */
-  constexpr error_type error_collate(_S_error_collate);
+  _GLIBCXX17_INLINE constexpr error_type error_collate(_S_error_collate);
 
   /** The expression contained an invalid character class name. */
-  constexpr error_type error_ctype(_S_error_ctype);
+  _GLIBCXX17_INLINE constexpr error_type error_ctype(_S_error_ctype);
 
   /**
    * The expression contained an invalid escaped character, or a trailing
    * escape.
    */
-  constexpr error_type error_escape(_S_error_escape);
+  _GLIBCXX17_INLINE constexpr error_type error_escape(_S_error_escape);
 
   /** The expression contained an invalid back reference. */
-  constexpr error_type error_backref(_S_error_backref);
+  _GLIBCXX17_INLINE constexpr error_type error_backref(_S_error_backref);
 
   /** The expression contained mismatched [ and ]. */
-  constexpr error_type error_brack(_S_error_brack);
+  _GLIBCXX17_INLINE constexpr error_type error_brack(_S_error_brack);
 
   /** The expression contained mismatched ( and ). */
-  constexpr error_type error_paren(_S_error_paren);
+  _GLIBCXX17_INLINE constexpr error_type error_paren(_S_error_paren);
 
   /** The expression contained mismatched { and } */
-  constexpr error_type error_brace(_S_error_brace);
+  _GLIBCXX17_INLINE constexpr error_type error_brace(_S_error_brace);
 
   /** The expression contained an invalid range in a {} expression. */
-  constexpr error_type error_badbrace(_S_error_badbrace);
+  _GLIBCXX17_INLINE constexpr error_type error_badbrace(_S_error_badbrace);
 
   /**
    * The expression contained an invalid character range,
    * such as [b-a] in most encodings.
    */
-  constexpr error_type error_range(_S_error_range);
+  _GLIBCXX17_INLINE constexpr error_type error_range(_S_error_range);
 
   /**
    * There was insufficient memory to convert the expression into a
    * finite state machine.
    */
-  constexpr error_type error_space(_S_error_space);
+  _GLIBCXX17_INLINE constexpr error_type error_space(_S_error_space);
 
   /**
    * One of <em>*?+{</em> was not preceded by a valid regular expression.
    */
-  constexpr error_type error_badrepeat(_S_error_badrepeat);
+  _GLIBCXX17_INLINE constexpr error_type error_badrepeat(_S_error_badrepeat);
 
   /**
    * The complexity of an attempted match against a regular expression
    * exceeded a pre-set level.
    */
-  constexpr error_type error_complexity(_S_error_complexity);
+  _GLIBCXX17_INLINE constexpr error_type error_complexity(_S_error_complexity);
 
   /**
    * There was insufficient memory to determine whether the
    * regular expression could match the specified character sequence.
    */
-  constexpr error_type error_stack(_S_error_stack);
+  _GLIBCXX17_INLINE constexpr error_type error_stack(_S_error_stack);
 
   ///@}
 } // namespace regex_constants
diff --git a/libstdc++-v3/include/ext/concurrence.h b/libstdc++-v3/include/ext/concurrence.h
index aea861b534f..7fd81490eff 100644
--- a/libstdc++-v3/include/ext/concurrence.h
+++ b/libstdc++-v3/include/ext/concurrence.h
@@ -50,7 +50,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 
   // Compile time constant that indicates prefered locking policy in
   // the current configuration.
-  static const _Lock_policy __default_lock_policy = 
+  _GLIBCXX17_INLINE const _Lock_policy __default_lock_policy =
 #ifndef __GTHREADS
   _S_single;
 #elif defined _GLIBCXX_HAVE_ATOMIC_LOCK_POLICY
diff --git a/libstdc++-v3/include/pstl/execution_defs.h b/libstdc++-v3/include/pstl/execution_defs.h
index 13b002931e8..3eca558dac2 100644
--- a/libstdc++-v3/include/pstl/execution_defs.h
+++ b/libstdc++-v3/include/pstl/execution_defs.h
@@ -107,10 +107,10 @@ class unsequenced_policy
 };
 
 // 2.8, Execution policy objects
-constexpr sequenced_policy seq{};
-constexpr parallel_policy par{};
-constexpr parallel_unsequenced_policy par_unseq{};
-constexpr unsequenced_policy unseq{};
+_GLIBCXX17_INLINE constexpr sequenced_policy seq{};
+_GLIBCXX17_INLINE constexpr parallel_policy par{};
+_GLIBCXX17_INLINE constexpr parallel_unsequenced_policy par_unseq{};
+_GLIBCXX17_INLINE constexpr unsequenced_policy unseq{};
 
 // 2.3, Execution policy type trait
 template <class _Tp>
-- 
2.38.1.381.gc03801e19c