[committed] libstdc++: Guard use of sized deallocation [PR114940]

[Jonathan Wakely]

Tested x86_64-linux. Pushed to trunk. Backport needed too.

-- >8 --

Clang does not enable -fsized-deallocation by default, which means it
can't compile our <stacktrace> and <generator> headers.

Make the __cpp_lib_generator macro depend on the compiler-defined
__cpp_sized_deallocation macro, and change <stacktrace> to use unsized
deallocation when __cpp_sized_deallocation isn't defined.

libstdc++-v3/ChangeLog:

        PR libstdc++/114940
        * include/bits/version.def (generator): Depend on
        __cpp_sized_deallocation.
        * include/bits/version.h: Regenerate.
        * include/std/stacktrace (_GLIBCXX_SIZED_DELETE): New macro.
        (basic_stacktrace::_Impl::_M_deallocate): Use it.
---
 libstdc++-v3/include/bits/version.def |  2 +-
 libstdc++-v3/include/bits/version.h   |  2 +-
 libstdc++-v3/include/std/stacktrace   | 13 +++++++++++--
 3 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/libstdc++-v3/include/bits/version.def 
b/libstdc++-v3/include/bits/version.def
index f0ba4f2bb3d..5cbc9d1a8d8 100644
--- a/libstdc++-v3/include/bits/version.def
+++ b/libstdc++-v3/include/bits/version.def
@@ -1651,7 +1651,7 @@ ftms = {
   values = {
     v = 202207;
     cxxmin = 23;
-    extra_cond = "__glibcxx_coroutine";
+    extra_cond = "__glibcxx_coroutine && __cpp_sized_deallocation";
   };
 };
 
diff --git a/libstdc++-v3/include/bits/version.h 
b/libstdc++-v3/include/bits/version.h
index f30f51dcedc..164ebed4983 100644
--- a/libstdc++-v3/include/bits/version.h
+++ b/libstdc++-v3/include/bits/version.h
@@ -1834,7 +1834,7 @@
 #undef __glibcxx_want_forward_like
 
 #if !defined(__cpp_lib_generator)
-# if (__cplusplus >= 202100L) && (__glibcxx_coroutine)
+# if (__cplusplus >= 202100L) && (__glibcxx_coroutine && 
__cpp_sized_deallocation)
 #  define __glibcxx_generator 202207L
 #  if defined(__glibcxx_want_all) || defined(__glibcxx_want_generator)
 #   define __cpp_lib_generator 202207L
diff --git a/libstdc++-v3/include/std/stacktrace 
b/libstdc++-v3/include/std/stacktrace
index d217d63af3b..962dbed7a41 100644
--- a/libstdc++-v3/include/std/stacktrace
+++ b/libstdc++-v3/include/std/stacktrace
@@ -551,6 +551,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
 #else
 # define _GLIBCXX_OPERATOR_NEW ::operator new
 # define _GLIBCXX_OPERATOR_DELETE ::operator delete
+#endif
+
+#if __cpp_sized_deallocation
+# define _GLIBCXX_SIZED_DELETE(T, p, n) \
+  _GLIBCXX_OPERATOR_DELETE((p), (n) * sizeof(T))
+#else
+# define _GLIBCXX_SIZED_DELETE(T, p, n) _GLIBCXX_OPERATOR_DELETE(p)
 #endif
 
        // Precondition: _M_frames == nullptr && __n != 0
@@ -592,8 +599,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
          if (_M_capacity)
            {
              if constexpr (is_same_v<allocator_type, allocator<value_type>>)
-               _GLIBCXX_OPERATOR_DELETE (static_cast<void*>(_M_frames),
-                                         _M_capacity * sizeof(value_type));
+               _GLIBCXX_SIZED_DELETE(value_type,
+                                     static_cast<void*>(_M_frames),
+                                     _M_capacity);
              else
                __alloc.deallocate(_M_frames, _M_capacity);
              _M_frames = nullptr;
@@ -601,6 +609,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
            }
        }
 
+#undef _GLIBCXX_SIZED_DELETE
 #undef _GLIBCXX_OPERATOR_DELETE
 #undef _GLIBCXX_OPERATOR_NEW
 
-- 
2.45.1