[gcc r15-8048] libstdc++: fix compile error when converting std::weak_ptr
https://gcc.gnu.org/g:df0e6509bf74421ea68a2e025300bcd6ca63722f
commit r15-8048-gdf0e6509bf74421ea68a2e025300bcd6ca63722f
Author: Giuseppe D'Angelo
Date: Tue Dec 10 00:56:13 2024 +0100
libstdc++: fix compile error when converting std::weak_ptr
A std::weak_ptr can be converted to a compatible
std::weak_ptr. This is implemented by having suitable converting
constructors to std::weak_ptr which dispatch to the __weak_ptr base
class (implementation detail).
In __weak_ptr, lock() is supposed to return a __shared_ptr,
not a __shared_ptr (that is, __shared_ptr).
Unfortunately the return type of lock() and the type of the returned
__shared_ptr were mismatching and that was causing a compile error: when
converting a __weak_ptr to a __weak_ptr through __weak_ptr's
converting constructor, the code calls lock(), and that simply fails to
build.
Fix it by removing the usage of element_type inside lock(), and using
_Tp instead.
Note that std::weak_ptr::lock() itself was already correct; the one in
__weak_ptr was faulty (and that is the one called by __weak_ptr's
converting constructors).
libstdc++-v3/ChangeLog:
* include/bits/shared_ptr_base.h (lock): Fixed a compile error
when calling lock() on a weak_ptr, by removing an
erroneous usage of element_type from within lock().
*
testsuite/20_util/shared_ptr/requirements/explicit_instantiation/1.cc:
Add more tests for array types.
*
testsuite/20_util/weak_ptr/requirements/explicit_instantiation/1.cc:
Likewise.
* testsuite/20_util/shared_ptr/requirements/1.cc: New test.
* testsuite/20_util/weak_ptr/requirements/1.cc: New test.
Diff:
---
libstdc++-v3/include/bits/shared_ptr_base.h| 2 +-
.../testsuite/20_util/shared_ptr/requirements/1.cc | 33 ++
.../requirements/explicit_instantiation/1.cc | 12
.../testsuite/20_util/weak_ptr/requirements/1.cc | 33 ++
.../requirements/explicit_instantiation/1.cc | 12
5 files changed, 91 insertions(+), 1 deletion(-)
diff --git a/libstdc++-v3/include/bits/shared_ptr_base.h
b/libstdc++-v3/include/bits/shared_ptr_base.h
index 053857b4c29f..3622e0291178 100644
--- a/libstdc++-v3/include/bits/shared_ptr_base.h
+++ b/libstdc++-v3/include/bits/shared_ptr_base.h
@@ -2075,7 +2075,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
__shared_ptr<_Tp, _Lp>
lock() const noexcept
- { return __shared_ptr(*this, std::nothrow); }
+ { return __shared_ptr<_Tp, _Lp>(*this, std::nothrow); }
long
use_count() const noexcept
diff --git a/libstdc++-v3/testsuite/20_util/shared_ptr/requirements/1.cc
b/libstdc++-v3/testsuite/20_util/shared_ptr/requirements/1.cc
new file mode 100644
index ..8ddb5d220ac7
--- /dev/null
+++ b/libstdc++-v3/testsuite/20_util/shared_ptr/requirements/1.cc
@@ -0,0 +1,33 @@
+// { dg-do compile { target c++11 } }
+// { dg-require-effective-target hosted }
+
+#include
+#include
+
+using namespace __gnu_test;
+
+void
+test01()
+{
+ std::shared_ptr ptr;
+ std::shared_ptr ptr2 = ptr;
+
+#if __cpp_lib_shared_ptr_arrays >= 201611L
+ std::shared_ptr ptr_array;
+ std::shared_ptr ptr_array2 = ptr_array;
+ std::shared_ptr ptr_array3 = ptr_array;
+#endif
+}
+
+void
+test02()
+{
+ std::shared_ptr ptr;
+ std::shared_ptr ptr2 = ptr;
+
+#if __cpp_lib_shared_ptr_arrays >= 201611L
+ std::shared_ptr ptr_array;
+ std::shared_ptr ptr_array2 = ptr_array;
+ std::shared_ptr ptr_array3 = ptr_array;
+#endif
+}
diff --git
a/libstdc++-v3/testsuite/20_util/shared_ptr/requirements/explicit_instantiation/1.cc
b/libstdc++-v3/testsuite/20_util/shared_ptr/requirements/explicit_instantiation/1.cc
index 6418e0c4bc7c..3bd05c36f8fc 100644
---
a/libstdc++-v3/testsuite/20_util/shared_ptr/requirements/explicit_instantiation/1.cc
+++
b/libstdc++-v3/testsuite/20_util/shared_ptr/requirements/explicit_instantiation/1.cc
@@ -28,3 +28,15 @@ template class std::shared_ptr;
template class std::shared_ptr;
template class std::shared_ptr;
template class std::shared_ptr;
+
+#if __cpp_lib_shared_ptr_arrays >= 201611L
+template class std::shared_ptr;
+template class std::shared_ptr;
+template class std::shared_ptr;
+template class std::shared_ptr;
+
+template class std::shared_ptr;
+template class std::shared_ptr;
+template class std::shared_ptr;
+template class std::shared_ptr;
+#endif
diff --git a/libstdc++-v3/testsuite/20_util/weak_ptr/requirements/1.cc
b/libstdc++-v3/testsuite/20_util/weak_ptr/requirements/1.cc
new file mode 100644
index ..04ea837d85a7
--- /dev/null
+++ b/libstdc++-v3/testsuite/20_util/weak_ptr/requirements/1.cc
@@ -0,0 +1,33 @@
+// { dg-do compile { target c++11 } }
+// { dg-require-effective-target hosted }
+
+#include
+#include
+
+using namespace __gnu_test;
+
+void
+test01()
+{
+ std::weak_ptr ptr;
+
[gcc r15-7746] MAINTAINERS: add myself to write after approval and DCO
https://gcc.gnu.org/g:a3f77f2528b9383c70f0361e0f3863cee58e9648 commit r15-7746-ga3f77f2528b9383c70f0361e0f3863cee58e9648 Author: Giuseppe D'Angelo Date: Fri Feb 28 08:37:25 2025 +0100 MAINTAINERS: add myself to write after approval and DCO ChangeLog: * MAINTAINERS: Added myself as write after approval and DCO. Diff: --- MAINTAINERS | 2 ++ 1 file changed, 2 insertions(+) diff --git a/MAINTAINERS b/MAINTAINERS index c423dd6e7874..193cd802a078 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -428,6 +428,7 @@ Ludovic Courtès ludo Cary Coutant- Lawrence Crowl crowl Lili Cui- +Giuseppe D'Angelo peppe Palmer Dabbelt palmer Ian Dalliandall David Daney daney @@ -929,6 +930,7 @@ information. Soumya AR Juergen Christ +Giuseppe D'Angelo Robin Dapp Robin Dapp Aldy Hernandez
[gcc r15-7908] libstdc++: constrain std::atomic's default constructor
https://gcc.gnu.org/g:613f8ddbe3d7da63d827e588bf0333813c184b8a
commit r15-7908-g613f8ddbe3d7da63d827e588bf0333813c184b8a
Author: Giuseppe D'Angelo
Date: Sat Sep 21 10:36:20 2024 +0200
libstdc++: constrain std::atomic's default constructor
This commit implements the proposed resolution to LWG4169, which is
to constrain std::atomic's default constructor based on whether
T itself is default constructible.
At the moment, std::atomic's primary template in libstdc++ has a
defaulted default constructor. Value-initialization of the T member
(since C++20 / P0883R2) is done via a NSDMI (= T()).
GCC already considers the defaulted constructor constrained/deleted,
however this behavior is non-standard (see the discussion in PR116769):
the presence of a NSDMI should not make the constructor unavailable to
overload resolution/deleted ([class.default.ctor]/2.5 does not apply).
When using libstdc++ on Clang, this causes build issues as the
constructor is *not* deleted there -- the interpretation of
[class.default.ctor]/4 seems to match Clang's behavior.
Therefore, although there would be "nothing to do" with GCC+libstdc++,
this commit changes the code as to stop relying on the GCC language
extension. In C++ >= 20 modes, std::atomic's defaulted default
constructor is changed to be a non-defaulted one, with a constraint
added as per LWG4169; value-initialization of the data member is moved
from the NSDMI to the member init list. The new signature matches the
one in the Standard as per [atomics.types.operations]/1.
In pre-C++20 modes, the constructor is left defaulted. This ensures
compatibility with C++11/14/17 behavior. In other words: we are not
backporting P0883R2 to earlier language modes here.
Amend an existing test to check that a std::atomic wrapping a
non-default constructible type is always non-default constructible:
from C++20, because of the constraint; before C++20, because we
are removing the NSDMI, and therefore [class.default.ctor]/2.5
applies.
Add another test that checks that std::atomic is trivially default
constructible in pre-C++20 modes, and it isn't afterwards.
libstdc++-v3/ChangeLog:
* include/bits/version.def (atomic_value_initialization):
Guard the FTM with the language concepts FTM.
* include/bits/version.h: Regenerate.
* include/std/atomic (atomic): When atomic value init is
defined, change the defaulted default constructor to
a non-defaulted one, constraining it as per LWG4169.
Otherwise, keep the existing constructor.
Remove the NSDMI for the _M_i member.
(_GLIBCXX20_INIT): Drop the macro, as it is not needed any more.
* testsuite/29_atomics/atomic/69301.cc: Test that
an atomic wrapping a non-default-constructible type is
always itself non-default-constructible (in all language
modes).
* testsuite/29_atomics/atomic/cons/trivial.cc: New test.
Diff:
---
libstdc++-v3/include/bits/version.def | 1 +
libstdc++-v3/include/bits/version.h| 2 +-
libstdc++-v3/include/std/atomic| 22 ++--
libstdc++-v3/testsuite/29_atomics/atomic/69301.cc | 2 ++
.../testsuite/29_atomics/atomic/cons/trivial.cc| 41 ++
5 files changed, 57 insertions(+), 11 deletions(-)
diff --git a/libstdc++-v3/include/bits/version.def
b/libstdc++-v3/include/bits/version.def
index 2af5a54bff28..56638759539b 100644
--- a/libstdc++-v3/include/bits/version.def
+++ b/libstdc++-v3/include/bits/version.def
@@ -770,6 +770,7 @@ ftms = {
values = {
v = 201911;
cxxmin = 20;
+extra_cond = "__cpp_concepts >= 201907L";
};
};
diff --git a/libstdc++-v3/include/bits/version.h
b/libstdc++-v3/include/bits/version.h
index 9833023cfdc8..29e1535298cb 100644
--- a/libstdc++-v3/include/bits/version.h
+++ b/libstdc++-v3/include/bits/version.h
@@ -856,7 +856,7 @@
#undef __glibcxx_want_atomic_ref
#if !defined(__cpp_lib_atomic_value_initialization)
-# if (__cplusplus >= 202002L)
+# if (__cplusplus >= 202002L) && (__cpp_concepts >= 201907L)
# define __glibcxx_atomic_value_initialization 201911L
# if defined(__glibcxx_want_all) ||
defined(__glibcxx_want_atomic_value_initialization)
# define __cpp_lib_atomic_value_initialization 201911L
diff --git a/libstdc++-v3/include/std/atomic b/libstdc++-v3/include/std/atomic
index cd08df34ba77..9b1aca0fc09a 100644
--- a/libstdc++-v3/include/std/atomic
+++ b/libstdc++-v3/include/std/atomic
@@ -51,6 +51,7 @@
#include
#include
+#include
namespace std _GLIBCXX_VISIBILITY(default)
{
@@ -189,14 +190,6 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
#endif // __cpp_lib_atomic_wait
};
-/// @cond undocumented
-#if __cpp_lib_atomic_value_initialization
-# define _GLIBCXX20_
[gcc r15-7838] libstdc++: use if consteval in stable_sort
https://gcc.gnu.org/g:24ea4539300d4926d9f073822e68f0d2f369452d
commit r15-7838-g24ea4539300d4926d9f073822e68f0d2f369452d
Author: Giuseppe D'Angelo
Date: Wed Mar 5 14:34:41 2025 +0100
libstdc++: use if consteval in stable_sort
This is a C++ >= 26 codepath for supporting constexpr stable_sort, so we
know that we have if consteval available; it just needs protection with
the feature-testing macro. Also merge the return in the same statement.
Amends r15-7708-gff43f9853d3b10.
libstdc++-v3/ChangeLog:
* include/bits/stl_algo.h (__stable_sort): Use if consteval
instead of is_constant_evaluated.
Reviewed-by: Jonathan Wakely
Diff:
---
libstdc++-v3/include/bits/stl_algo.h | 10 +-
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/libstdc++-v3/include/bits/stl_algo.h
b/libstdc++-v3/include/bits/stl_algo.h
index 41b4d0853b71..c3fea76014cb 100644
--- a/libstdc++-v3/include/bits/stl_algo.h
+++ b/libstdc++-v3/include/bits/stl_algo.h
@@ -4987,11 +4987,11 @@ _GLIBCXX_BEGIN_NAMESPACE_ALGO
return;
#if _GLIBCXX_HOSTED
- if (__is_constant_evaluated())
- {
- std::__inplace_stable_sort(__first, __last, __comp);
- return;
- }
+# if __glibcxx_constexpr_algorithms >= 202306L // >= C++26
+ if consteval {
+ return std::__inplace_stable_sort(__first, __last, __comp);
+ }
+# endif
typedef _Temporary_buffer<_RandomAccessIterator, _ValueType> _TmpBuf;
// __stable_sort_adaptive sorts the range in two halves,
[gcc r15-8970] libstdc++: add constexpr stable_partition
https://gcc.gnu.org/g:aba3018af8e025a62a87c704ccad6714b13bc811
commit r15-8970-gaba3018af8e025a62a87c704ccad6714b13bc811
Author: Giuseppe D'Angelo
Date: Sat Mar 15 00:15:36 2025 +0100
libstdc++: add constexpr stable_partition
This completes the implementation of P2562R1 for C++26.
Unlike the other constexpr algorithms of the same family,
stable_partition does not have a constexpr-friendly version "ready to
use" during constant evaluation. In fact, it is not even available on
freestanding, because it always allocates a temporary memory buffer.
This commit implements the simplest possible strategy: during constant
evaluation allocate a buffer of length 1 on the stack, and use that as
a working area.
libstdc++-v3/ChangeLog:
* include/bits/algorithmfwd.h (stable_partition): Mark it
as constexpr for C++26.
* include/bits/ranges_algo.h (__stable_partition_fn): Likewise.
* include/bits/stl_algo.h (stable_partition): Mark it as
constexpr for C++26; during constant evaluation use a new
codepath where a temporary buffer of 1 element is used.
* testsuite/25_algorithms/headers/algorithm/synopsis.cc
(stable_partition): Add constexpr.
* testsuite/25_algorithms/stable_partition/constexpr.cc: New test.
Diff:
---
libstdc++-v3/include/bits/algorithmfwd.h | 1 +
libstdc++-v3/include/bits/ranges_algo.h| 2 +
libstdc++-v3/include/bits/stl_algo.h | 21 ++-
.../25_algorithms/headers/algorithm/synopsis.cc| 1 +
.../25_algorithms/stable_partition/constexpr.cc| 44 ++
5 files changed, 67 insertions(+), 2 deletions(-)
diff --git a/libstdc++-v3/include/bits/algorithmfwd.h
b/libstdc++-v3/include/bits/algorithmfwd.h
index 05894b580028..a727b2783814 100644
--- a/libstdc++-v3/include/bits/algorithmfwd.h
+++ b/libstdc++-v3/include/bits/algorithmfwd.h
@@ -649,6 +649,7 @@ _GLIBCXX_END_INLINE_ABI_NAMESPACE(_V2)
#if _GLIBCXX_HOSTED
template
+_GLIBCXX26_CONSTEXPR
_BIter
stable_partition(_BIter, _BIter, _Predicate);
#endif
diff --git a/libstdc++-v3/include/bits/ranges_algo.h
b/libstdc++-v3/include/bits/ranges_algo.h
index 2814d90061cc..f36e7dd59911 100644
--- a/libstdc++-v3/include/bits/ranges_algo.h
+++ b/libstdc++-v3/include/bits/ranges_algo.h
@@ -2389,6 +2389,7 @@ namespace ranges
typename _Proj = identity,
indirect_unary_predicate> _Pred>
requires permutable<_Iter>
+ _GLIBCXX26_CONSTEXPR
subrange<_Iter>
operator()(_Iter __first, _Sent __last,
_Pred __pred, _Proj __proj = {}) const
@@ -2404,6 +2405,7 @@ namespace ranges
indirect_unary_predicate, _Proj>>
_Pred>
requires permutable>
+ _GLIBCXX26_CONSTEXPR
borrowed_subrange_t<_Range>
operator()(_Range&& __r, _Pred __pred, _Proj __proj = {}) const
{
diff --git a/libstdc++-v3/include/bits/stl_algo.h
b/libstdc++-v3/include/bits/stl_algo.h
index bb7dbfbd8e04..71ead103d2bf 100644
--- a/libstdc++-v3/include/bits/stl_algo.h
+++ b/libstdc++-v3/include/bits/stl_algo.h
@@ -1447,6 +1447,7 @@ _GLIBCXX_END_INLINE_ABI_NAMESPACE(_V2)
/// move-assign an element onto itself.
template
+_GLIBCXX26_CONSTEXPR
_ForwardIterator
__stable_partition_adaptive(_ForwardIterator __first,
_ForwardIterator __last,
@@ -1507,6 +1508,7 @@ _GLIBCXX_END_INLINE_ABI_NAMESPACE(_V2)
}
template
+_GLIBCXX26_CONSTEXPR
_ForwardIterator
__stable_partition(_ForwardIterator __first, _ForwardIterator __last,
_Predicate __pred)
@@ -1521,11 +1523,25 @@ _GLIBCXX_END_INLINE_ABI_NAMESPACE(_V2)
typedef typename iterator_traits<_ForwardIterator>::difference_type
_DistanceType;
+ const _DistanceType __len = std::distance(__first, __last);
+
+#if __glibcxx_constexpr_algorithms >= 202306L // >= C++26
+ if consteval {
+ // Simulate a _Temporary_buffer of length 1:
+ _ValueType __buf = std::move(*__first);
+ *__first = std::move(__buf);
+ return std::__stable_partition_adaptive(__first, __last, __pred,
+ __len,
+ &__buf,
+ _DistanceType(1));
+ }
+#endif
+
_Temporary_buffer<_ForwardIterator, _ValueType>
- __buf(__first, std::distance(__first, __last));
+ __buf(__first, __len);
return
std::__stable_partition_adaptive(__first, __last, __pred,
-_DistanceType(__buf.requested_size()),
+__len,
__buf.begin(),
_DistanceType(__buf.size()));
}
@@ -1548,6 +1564,7 @@ _GLIBCXX_END_
