More function decorations

[Jan Hubicka <hubicka at ucw dot cz>]

Hi,
this patch adds Paolo's _GLIBCXX_PURE and _GLIBCXX_CONST macros.  I also
added _GLIBCXX_NORETURN that is important marker too.
For _GLIBCXX_NORETURN I found only one use so far that is in _M_error of
debug/formater.h and I added decorations to the stl_tree to finish the
file and started in Makefile order with atomic.cc
I noticed that atomic already have __attribute__ ((const)) marker and it
is missing __const__ around it, so I decided to stop here and discuss
procedure.  I guess we want to update them to _GLIBCXX_CONST macros for
consistency?

Tested on x86_64-linux
Honza

	* include/debug/formater.h: Include bits/c++config.h.
	(_M_error): Mark noreturn.
	* include/bits/c++config (_GLIBCXX_PURE, _GLIBCXX_CONST,
	_GLIBCXX_NORETURN): New.
	* include/bits/stl_tree.h (_Rb_tree_increment, _Rb_tree_increment,
	_Rb_tree_decrement, _Rb_tree_decrement, _Rb_tree_black_count): Mark pure.
	* include/c_compatibility/stdatomic.h (atomic_flag_test_and_set_explicit,
	atomic_flag_clear_explicit, __atomic_flag_wait_explicit,
	__atomic_flag_for_address): Mark by throw ().
	* src/atomic.cc (atomic_flag_test_and_set_explicit,
	atomic_flag_clear_explicit, __atomic_flag_wait_explicit,
	__atomic_flag_for_address): Mark by throw ().
Index: src/atomic.cc
===================================================================
--- src/atomic.cc	(revision 146188)
+++ src/atomic.cc	(working copy)
@@ -78,7 +78,7 @@
   {
     bool
     atomic_flag_test_and_set_explicit(volatile __atomic_flag_base* __a,
-				      memory_order __m)
+				      memory_order __m) throw ()
     {
       volatile atomic_flag d(__a->_M_i);
       return d.test_and_set(__m);
@@ -86,7 +86,7 @@
 
     void
     atomic_flag_clear_explicit(volatile __atomic_flag_base* __a,
-			       memory_order __m)
+			       memory_order __m) throw ()
     {
       volatile atomic_flag d(__a->_M_i);
       return d.clear(__m);
@@ -94,14 +94,14 @@
 
     void
     __atomic_flag_wait_explicit(volatile __atomic_flag_base* __a,
-				memory_order __x)
+				memory_order __x) throw ()
     {
       while (atomic_flag_test_and_set_explicit(__a, __x))
 	{ };
     }
 
     volatile __atomic_flag_base*
-    __atomic_flag_for_address(const volatile void* __z)
+    __atomic_flag_for_address(const volatile void* __z) throw ()
     {
       uintptr_t __u = reinterpret_cast<uintptr_t>(__z);
       __u += (__u >> 2) + (__u << 4);
Index: include/debug/formatter.h
===================================================================
--- include/debug/formatter.h	(revision 146188)
+++ include/debug/formatter.h	(working copy)
@@ -29,6 +29,7 @@
 #ifndef _GLIBCXX_DEBUG_FORMATTER_H
 #define _GLIBCXX_DEBUG_FORMATTER_H 1
 
+#include <bits/c++config.h>
 #include <typeinfo>
 #include <debug/debug.h>
 
@@ -347,7 +348,7 @@
     const _Error_formatter&
     _M_message(_Debug_msg_id __id) const;
 
-    void
+    _GLIBCXX_NORETURN void
     _M_error() const;
 
   private:
Index: include/bits/c++config
===================================================================
--- include/bits/c++config	(revision 146188)
+++ include/bits/c++config	(working copy)
@@ -314,4 +314,16 @@
 #undef min
 #undef max
 
+#ifndef _GLIBCXX_PURE
+# define _GLIBCXX_PURE __attribute__ ((__pure__))
+#endif
+
+#ifndef _GLIBCXX_CONST
+# define _GLIBCXX_CONST __attribute__ ((__const__))
+#endif
+
+#ifndef _GLIBCXX_NORETURN
+# define _GLIBCXX_NORETURN __attribute__ ((__noreturn__))
+#endif
+
 // End of prewritten config; the discovered settings follow.
Index: include/bits/stl_tree.h
===================================================================
--- include/bits/stl_tree.h	(revision 146188)
+++ include/bits/stl_tree.h	(working copy)
@@ -137,16 +137,16 @@
 #endif
     };
 
-  _Rb_tree_node_base*
+  _GLIBCXX_PURE _Rb_tree_node_base*
   _Rb_tree_increment(_Rb_tree_node_base* __x) throw ();
 
-  const _Rb_tree_node_base*
+  _GLIBCXX_PURE const _Rb_tree_node_base*
   _Rb_tree_increment(const _Rb_tree_node_base* __x) throw ();
 
-  _Rb_tree_node_base*
+  _GLIBCXX_PURE _Rb_tree_node_base*
   _Rb_tree_decrement(_Rb_tree_node_base* __x) throw ();
 
-  const _Rb_tree_node_base*
+  _GLIBCXX_PURE const _Rb_tree_node_base*
   _Rb_tree_decrement(const _Rb_tree_node_base* __x) throw ();
 
   template<typename _Tp>
@@ -1448,7 +1448,7 @@
       return __n;
     }
 
-  unsigned int
+  _GLIBCXX_PURE unsigned int
   _Rb_tree_black_count(const _Rb_tree_node_base* __node,
                        const _Rb_tree_node_base* __root) throw ();
 
Index: include/c_compatibility/stdatomic.h
===================================================================
--- include/c_compatibility/stdatomic.h	(revision 146188)
+++ include/c_compatibility/stdatomic.h	(working copy)
@@ -121,24 +121,24 @@
 
   // Accessor functions for base atomic_flag type.
   bool 
-  atomic_flag_test_and_set_explicit(volatile __atomic_flag_base*, memory_order);
+  atomic_flag_test_and_set_explicit(volatile __atomic_flag_base*, memory_order) throw ();
 
   inline bool 
   atomic_flag_test_and_set(volatile __atomic_flag_base* __a)
   { return atomic_flag_test_and_set_explicit(__a, memory_order_seq_cst); }
   
   void 
-  atomic_flag_clear_explicit(volatile __atomic_flag_base*, memory_order);
+  atomic_flag_clear_explicit(volatile __atomic_flag_base*, memory_order) throw ();
 
   inline void 
   atomic_flag_clear(volatile __atomic_flag_base* __a)
   { atomic_flag_clear_explicit(__a, memory_order_seq_cst); }
 
   void 
-  __atomic_flag_wait_explicit(volatile __atomic_flag_base*, memory_order);
+  __atomic_flag_wait_explicit(volatile __atomic_flag_base*, memory_order) throw ();
   
   volatile __atomic_flag_base* 
-  __atomic_flag_for_address(const volatile void* __z) __attribute__((const));
+  __atomic_flag_for_address(const volatile void* __z) throw () __attribute__((const));
 
   // Implementation specific defines.
 #define _ATOMIC_LOAD_(__a, __x)						\