[gcc r11-2979] libstdc++: Break header cycle between <new> and <exception>

[Jonathan Wakely <redi@gcc.gnu.org>]

https://gcc.gnu.org/g:6bdbf0f37bda2587a4e82cbb956de7a159a397ae

commit r11-2979-g6bdbf0f37bda2587a4e82cbb956de7a159a397ae
Author: Jonathan Wakely <jwakely@redhat.com>
Date:   Wed Sep 2 13:27:57 2020 +0100

    libstdc++: Break header cycle between <new> and <exception>
    
    The <new> and <exception> headers each include each other, which makes
    building them as header-units "exciting". The <new> header only needs
    the definition of std::exception (in order to derive from it) which is
    already in its own header, so just include that.
    
    libstdc++-v3/ChangeLog:
    
            * include/bits/stl_iterator.h: Include <bits/exception_defines.h>
            for definitions of __try, __catch and __throw_exception_again.
            (counted_iterator::operator++(int)): Use __throw_exception_again
            instead of throw.
            * libsupc++/new: Include <bits/exception.h> not <exception>.
            * libsupc++/new_opvnt.cc: Include <bits/exception_defines.h>.
            * testsuite/18_support/destroying_delete.cc: Include
            <type_traits> for std::is_same_v definition.
            * testsuite/20_util/variant/index_type.cc: Qualify size_t.

Diff:
---
 libstdc++-v3/include/bits/stl_iterator.h               | 3 ++-
 libstdc++-v3/libsupc++/new                             | 4 ++--
 libstdc++-v3/libsupc++/new_opvnt.cc                    | 3 ++-
 libstdc++-v3/testsuite/18_support/destroying_delete.cc | 1 +
 libstdc++-v3/testsuite/20_util/variant/index_type.cc   | 2 +-
 5 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/libstdc++-v3/include/bits/stl_iterator.h b/libstdc++-v3/include/bits/stl_iterator.h
index f0cf4c55c09..da740e3732e 100644
--- a/libstdc++-v3/include/bits/stl_iterator.h
+++ b/libstdc++-v3/include/bits/stl_iterator.h
@@ -79,6 +79,7 @@
 #if __cplusplus > 201703L
 # include <compare>
 # include <new>
+# include <bits/exception_defines.h>
 # include <bits/iterator_concepts.h>
 #endif
 
@@ -2062,7 +2063,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 	    return _M_current++;
 	  } __catch(...) {
 	    ++_M_length;
-	    throw;
+	    __throw_exception_again;
 	  }
 
       }
diff --git a/libstdc++-v3/libsupc++/new b/libstdc++-v3/libsupc++/new
index ebd1c490282..21848a573d1 100644
--- a/libstdc++-v3/libsupc++/new
+++ b/libstdc++-v3/libsupc++/new
@@ -38,7 +38,7 @@
 #pragma GCC system_header
 
 #include <bits/c++config.h>
-#include <exception>
+#include <bits/exception.h>
 
 #pragma GCC visibility push(default)
 
@@ -52,7 +52,7 @@ namespace std
    *
    *  @c bad_alloc (or classes derived from it) is used to report allocation
    *  errors from the throwing forms of @c new.  */
-  class bad_alloc : public exception 
+  class bad_alloc : public exception
   {
   public:
     bad_alloc() throw() { }
diff --git a/libstdc++-v3/libsupc++/new_opvnt.cc b/libstdc++-v3/libsupc++/new_opvnt.cc
index 9f9dace5778..771696d4ba6 100644
--- a/libstdc++-v3/libsupc++/new_opvnt.cc
+++ b/libstdc++-v3/libsupc++/new_opvnt.cc
@@ -25,7 +25,8 @@
 
 #include <bits/c++config.h>
 #include "new"
- 
+#include "exception_defines.h"
+
 _GLIBCXX_WEAK_DEFINITION void*
 operator new[] (std::size_t sz, const std::nothrow_t&) noexcept
 {
diff --git a/libstdc++-v3/testsuite/18_support/destroying_delete.cc b/libstdc++-v3/testsuite/18_support/destroying_delete.cc
index 96134d7e010..f0c9bb9fa25 100644
--- a/libstdc++-v3/testsuite/18_support/destroying_delete.cc
+++ b/libstdc++-v3/testsuite/18_support/destroying_delete.cc
@@ -19,6 +19,7 @@
 // { dg-do run { target c++2a } }
 
 #include <new>
+#include <type_traits>
 #include <testsuite_hooks.h>
 
 #ifndef __cpp_lib_destroying_delete
diff --git a/libstdc++-v3/testsuite/20_util/variant/index_type.cc b/libstdc++-v3/testsuite/20_util/variant/index_type.cc
index 73863fa677f..1c44758363c 100644
--- a/libstdc++-v3/testsuite/20_util/variant/index_type.cc
+++ b/libstdc++-v3/testsuite/20_util/variant/index_type.cc
@@ -22,4 +22,4 @@
 #include <variant>
 
 static_assert(sizeof(std::variant<signed char, unsigned char>)
-	      < sizeof(size_t));
+	      < sizeof(std::size_t));