The old version of _Sp_counted_ptr_inplace::_M_get_deleter (up to GCC
8.2.0) expects to be passed a real std::typeinfo object, so mixing that
with the new definition of the __shared_ptr constructor (which always
passes the fake tag) leads to accessing the fake object as a real
std::typeinfo. Instead of trying to make it safe to mix the old and new
definitions, just stop using that function. By passing a reference to
__shared_ptr::_M_ptr to the __shared_count constructor it can be set
directly, without needing to obtain the pointer via the _M_get_deleter
back-channel. This avoids a virtual dispatch (which fixes PR 87514).
This means that code built against new libstdc++ headers doesn't use
_M_get_deleter at all, and so make_shared works the same whether RTTI is
enabled or not.
Also change _M_get_deleter so that it checks for a real type_info object
even when RTTI is disabled, by calling a library function. Unless
libstdc++ itself is built without RTTI that library function will be
able to test if it's the right type_info. This means the new definition
of _M_get_deleter can handle both the fake type_info tag and a real
type_info object, even if built without RTTI.
If linking to objects built against older versions of libstdc++ then if
all objects use -frtti or all use -fno-rtti, then the caller of
_M_get_deleter and the definition of _M_get_deleter will be consistent
and it will work. If mixing -frtti with -fno-rtti it can still fail if
the linker picks an old definition of _M_get_deleter and an old
__shared_ptr constructor that are incompatible. In that some or all
objects might need to be recompiled.
PR libstdc++/87514
PR libstdc++/87520
PR libstdc++/88782
* config/abi/pre/gnu.ver (GLIBCXX_3.4.26): Export new symbol.
* include/bits/shared_ptr.h
(shared_ptr(_Sp_make_shared_tag, const Alloc&, Args&&...))
(allocate_shared): Change to use new tag type.
* include/bits/shared_ptr_base.h (_Sp_make_shared_tag::_S_eq):
Declare new member function.
(_Sp_alloc_shared_tag): Define new type.
(_Sp_counted_ptr_inplace): Declare __shared_count<_Lp> as a friend.
(_Sp_counted_ptr_inplace::_M_get_deleter) [!__cpp_rtti]: Use
_Sp_make_shared_tag::_S_eq to check type_info.
(__shared_count(Ptr, Deleter),__shared_count(Ptr, Deleter, Alloc)):
Constrain to prevent being called with _Sp_alloc_shared_tag.
(__shared_count(_Sp_make_shared_tag, const _Alloc&, Args&&...)):
Replace constructor with ...
(__shared_count(Tp*&, _Sp_alloc_shared_tag<_Alloc>, Args&&...)): Use
reference parameter so address of the new object can be returned to
the caller. Obtain the allocator from the tag type.
(__shared_ptr(_Sp_make_shared_tag, const Alloc&, Args&&...)): Replace
constructor with ...
(__shared_ptr(_Sp_alloc_shared_tag<Alloc>, Args&&...)): Pass _M_ptr
to the __shared_count constructor.
(__allocate_shared): Change to use new tag type.
* src/c++11/shared_ptr.cc (_Sp_make_shared_tag::_S_eq): Define.
From-SVN: r268086
This resolves a longstanding issue where the lock policy for shared_ptr
reference counting depends on compilation options when the header is
included, so that different -march options can cause ABI changes. For
example, objects compiled with -march=armv7 will use atomics to
synchronize reference counts, and objects compiled with -march=armv5t
will use a mutex. That means the shared_ptr control block will have a
different layout in different objects, causing ODR violations and
undefined behaviour. This was the root cause of PR libstdc++/42734 as
well as PR libstdc++/67843.
The solution is to decide on the lock policy at build time, when
libstdc++ is configured. The configure script checks for the
availability of the necessary atomic built-ins for the target and fixes
that choice permanently. Different -march flags used to compile user
code will not cause changes to the lock policy. This results in an ABI
change for certain compilations, but only where there was already an ABI
incompatibility between the libstdc++.so library and objects built with
an incompatible -march option. In general, this means a more stable ABI
that isn't silently altered when -march flags make addition atomic ops
available.
To force a target to use "atomic" or "mutex" the new configure option
--with-libstdcxx-lock-policy can be used.
In order to turn ODR violations into linker errors, the uses of
shared_ptr in filesystem directory iterators have been replaced
with __shared_ptr, and explicit instantiations are declared. This
ensures that object files using those types cannot link to libstdc++
libs unless they use the same lock policy.
PR libstdc++/67843
* acinclude.m4 (GLIBCXX_ENABLE_LOCK_POLICY): Add new macro
that defines _GLIBCXX_HAVE_ATOMIC_LOCK_POLICY.
* config.h.in: Regenerate.
* configure: Regenerate.
* configure.ac: Use GLIBCXX_ENABLE_LOCK_POLICY.
* doc/xml/manual/configure.xml: Document new configure option.
* include/bits/fs_dir.h (directory_iterator): Use __shared_ptr
instead of shared_ptr.
(recursive_directory_iterator): Likewise.
(__shared_ptr<_Dir>): Add explicit instantiation declaration.
(__shared_ptr<recursive_directory_iterator::_Dir_stack>): Likewise.
* include/bits/shared_ptr_base.h (__allocate_shared, __make_shared):
Add default template argument for _Lock_policy template parameter.
* include/ext/concurrence.h (__default_lock_policy): Check macro
_GLIBCXX_HAVE_ATOMIC_LOCK_POLICY instead of checking if the current
target supports the builtins for compare-and-swap.
* src/filesystem/std-dir.cc (__shared_ptr<_Dir>): Add explicit
instantiation definition.
(__shared_ptr<recursive_directory_iterator::_Dir_stack>): Likewise.
(directory_iterator, recursive_directory_iterator): Use __make_shared
instead of make_shared.
From-SVN: r266533
The implementations of std::make_shared for -frtti and -fno-rtti are not
compatible, because they pass different arguments to
_Sp_counted_ptr_inplace::_M_get_deleter and so can't interoperate.
Either the argument doesn't match the expected value, and so the
shared_ptr::_M_ptr member is never set, or the type-punned reference is
treated as a real std::type_info object and gets dereferenced.
This patch removes the differences between -frtti and -fno-rtti, so that
typeid is never used, and the type-punned reference is used in both
cases. For backwards compatibility with existing code that passes
typeid(_Sp_make_shared_tag) that still needs to be handled, but only
after checking that the argument is not the type-punned reference (so
it's safe to treat as a real std::type_info object). The reference is
bound to an object of literal type, so that it doesn't need a guard
variable to make its initialization thread-safe.
This patch also fixes 87520 by ensuring that the type-punned reference
is bound to "a region of storage of suitable size and alignment to
contain an object of the reference's type" (as per the proposed
resolution of Core DR 453).
If all objects are built with the fixed version of GCC then -frtti and
-fno-rtti can be mixed freely and std::make_shared will work correctly.
If some objects are built with unfixed GCC versions then problems can
still arise, depending on which template instantiations are kept by the
linker.
PR libstdc++/85930
PR libstdc++/87520
* include/bits/shared_ptr_base.h (_Sp_make_shared_tag::_S_ti)
[__cpp_rtti]: Define even when RTTI is enabled. Use array of
sizeof(type_info) so that type-punned reference binds to an object
of the correct size as well as correct alignment.
(_Sp_counted_ptr_inplace::_M_get_deleter) [__cpp_rtti]: Check for
_S_ti() reference even when RTTI is enabled.
(__shared_ptr(_Sp_make_shared_tag, const _Alloc&, _Args&&...))
[__cpp_rtti]: Pass _S_ti() instead of typeid(_Sp_make_shared_tag).
From-SVN: r266376
Clang (including trunk and many older versions) incorrectly marks static
local variables (__tag) hidden when -fvisibility-inlines-hidden is used.
This can lead to multiple instances of __tag when shares objects are used.
2018-07-20 Fangrui Song <maskray@google.com>
* include/bits/shared_ptr_base.h (_Sp_make_shared_tag::_S_ti): Use
_GLIBCXX_VISIBILITY(default).
From-SVN: r262903
The standard doesn't specify this partial specialization (it was
required after the changes in N2637 but then should have been removed
following LWG 1262). Its presence is observable because it causes
different results when operator< has been overloaded for a shared_ptr
specialization.
PR libstdc++/86537
* include/bits/shared_ptr.h (less<shared_ptr<_Tp>>): Remove
non-standard partial specialization.
* include/bits/shared_ptr_base.h (_Sp_less): Remove class definition.
(less<__shared_ptr<_Tp, _Lp>): Remove partial specialization.
* testsuite/20_util/shared_ptr/comparison/86537.cc: New test.
From-SVN: r262739
PR libstdc++/80285
* include/bits/shared_ptr_base.h (_Sp_make_shared_tag::_S_ti): Define
function to get unique fake std::type_info reference.
(_Sp_counted_ptr_inplace::_M_get_deleter) [!__cpp_rtti]: Compare to
_S_ti() fake reference.
(__shared_ptr(_Sp_make_shared_tag, const Alloc&, Args&&...)): Share
single implementation with or without RTTI enable.
[!__cpp_rtti]: Pass fake reference to _M_get_deleter.
* testsuite/20_util/shared_ptr/creation/alloc.cc: Change expected
allocation and deallocation counts.
* testsuite/20_util/shared_ptr/creation/single_allocation.cc: New.
* testsuite/20_util/shared_ptr/creation/single_allocation_no_rtti.cc:
New.
From-SVN: r247905
PR libstdc++/80229
* include/bits/shared_ptr_base.h
(__shared_ptr::_M_enable_shared_from_this_with): Change parameters to
non-const and then use remove_cv to get unqualified type.
* testsuite/20_util/enable_shared_from_this/members/const.cc: Don't
cast away constness on object created const.
* testsuite/20_util/shared_ptr/cons/80229.cc: New test.
From-SVN: r246520
* include/bits/invoke.h (__invoke): Use __invoke_result instead of
result_of, and __is_nothrow_invocable instead of
__is_nothrow_callable.
* include/bits/shared_ptr_base.h (__shared_ptr): Use __is_invocable
instead of __is_callable.
* include/std/functional (invoke): use invoke_result_t instead of
result_of_t and is_nothrow_invocable instead of is_nothrow_callable.
(_Not_fn): Use __invoke_result instead of result_of.
* include/std/type_traits (__result_of_memobj, __result_of_memfun):
Remove partial specializations for reference_wrapper types.
(__result_of_impl): Use __inv_unwrap to strip reference_wrapper.
(__invoke_result): Define replacement for result_of and then use it to
define result_of.
(__is_callable_impl, __is_callable, __is_nothrow_callable): Replace
with __is_invocable_impl, __is_invocable, and __is_nothrow_invocable
respectively.
(invoke_result, invoke_result_t): Define for C++17.
(is_callable, is_nothrow_callable): Replace with is_invocable,
is_invocable_r, is_nothrow_invocable, and is_nothrow_invocable_r.
(is_callable_v, is_nothrow_callable_v): Replace with is_invocable_v,
is_invocable_r_v, is_nothrow_invocable_v, and is_nothrow_invocable_r_v.
* include/std/variant (hash<variant<T...>>): Use is_nothrow_invocable_v
instead of is_nothrow_callable_v.
* testsuite/20_util/function_objects/invoke/59768.cc: Remove unused
main function.
* testsuite/20_util/function_objects/not_fn/1.cc: Use is_invocable
instead of is_callable.
* testsuite/20_util/is_callable/*: Rename directory and adjust tests
to use new traits.
* testsuite/20_util/is_notjrow_callable/*: Likewise.
* testsuite/20_util/optional/hash.cc: Use is_invocable_v instead of
is_callable.
* testsuite/20_util/variant/hash.cc: Likewise.
From-SVN: r246036
* doc/xml/manual/status_cxx2017.xml: Update status.
* doc/html/manual/status.html: Regenerate.
* include/bits/shared_ptr.h (shared_ptr(unique_ptr<_Yp, _Del>)): Add
extension constructor to maintain C++14 behaviour.
* include/bits/shared_ptr_base.h (__sp_array_delete): Add new struct.
(__shared_count(_Ptr, false_type), __shared_count(_Ptr, true_type)):
New constructors.
(__sp_compatible_with, __sp_is_constructible): Add specializations
for array support.
(__sp_is_constructible_arr, __sp_is_constructible_arrN): New helpers.
(__shared_ptr_access): New base class for observer member functions.
(__shared_ptr::element_type): Use remove_extent.
(__shared_ptr::_UniqCompatible): Add __sp_compatible_with check.
(__shared_ptr(_Yp*)): Use tag dispatching to call new __shared_count
constructor.
(__shared_ptr(unique_ptr<_Yp, _Del>)): Add extension constructor.
(__shared_ptr::operator*, __shared_ptr::operator->): Remove and
inherit from __shared_ptr_access base class.
(__shared_ptr::__has_esft_base): Return false for array types.
(__weak_ptr::element_type): Use remove_extent.
* include/experimental/bits/shared_ptr.h (__libfund_v1): Remove.
(__shared_ptr<__libfund_v1<_Tp>>): Remove specializations.
(__wak_ptr<__libfund_v1<_Tp>>): Likewise.
(experimental::__sp_compatible_v): Redefine using
__sp_compatible_with.
(experimental::__sp_is_constructible_v): Redefine using
__sp_is_constructible.
(get_deleter, operator<<): Change argument from __shared_ptr to
shared_ptr.
* testsuite/20_util/shared_ptr/cons/array.cc: New test.
* testsuite/20_util/shared_ptr/cons/unique_ptr_array.cc: Adjust for
new behaviour.
* testsuite/20_util/shared_ptr/observers/array.cc: Test observers for
arrays.
* testsuite/20_util/shared_ptr/observers/array_neg.cc: New test.
From-SVN: r242369
* include/backward/auto_ptr.h (__shared_ptr(auto_ptr&&))
(shared_ptr(auto_ptr&&)): Adjust template parameter lists.
* include/bits/shared_ptr.h (__sp_compatible_with)
(__sp_is_constructible): New helper traits for shared_ptr.
(shared_ptr::_Convertible): Replace with _Constructible.
(shared_ptr::_Constructible, shared_ptr::_Assignable): Forward checks
to base class.
(shared_ptr::shared_ptr, shared_ptr::operator=): Constrain template
with _Constructible and _Assignable.
(shared_ptr::shared_ptr(shared_ptr<_Tp1>, _Tp*)): Use element_type
instead of _Tp.
(operator<): Likewise.
(operator>): Define in terms of operator<.
(static_pointer_cast, const_pointer_cast, dynamic_pointer_cast): Use
element_type instead of _Tp.
(reinterpret_pointer_cast): Define for C++17.
(weak_ptr::_Convertible): Replace with _Constructible.
(weak_ptr::_Constructible, weak_ptr::_Assignable): Forward checks
to base class.
(weak_ptr::weak_ptr, weak_ptr::operator=): Constrain templates
with _Constructible and _Assignable.
* include/bits/shared_ptr_base.h (__shared_ptr::_Convertible): Replace
with _Compatible.
(__shared_ptr::_SafeConv): New constraint for incoming raw pointers.
(__shared_ptr::_Compatible): New constraint for converting from
other types of shared_ptr and weak_ptr.
(__shared_ptr::_Assignable): Define in terms of _Compatible.
(__shared_ptr::_UniqCompatible, __shared_ptr::_UniqAssignable): New
constraints for converting from unique_ptr.
(__shared_ptr::__shared_ptr, __shared_ptr::operator=): Constrain
template with _SaveConf, _Compatible and _Assignable. Remove
__glibcxx_function_requires concept checks. Add static assertion for
deleter expression being well-formed.
(__shared_ptr::__shared_ptr(__shared_ptr<_Tp1>, _Tp*))
(__shared_ptr::operator*, __shared_ptr::operator->)
(__shared_ptr::get, __shared_ptr::_M_ptr): Use element_type instead
of _Tp.
(operator<): Likewise.
(operator>): Define in terms of operator<.
(static_pointer_cast, const_pointer_cast, dynamic_pointer_cast): Use
element_type instead of _Tp.
(reinterpret_pointer_cast): Define for C++17.
(weak_ptr::_Convertible): Replace with _Compatible.
(weak_ptr::_Compatible, weak_ptr::_Assignable): New constraints for
conversions from other types of weak_ptr and shared_ptr.
(__weak_ptr::__weak_ptr, __weak_ptr::operator=): Constrain templates
with _Constructible and _Assignable.
(__weak_ptr::_M_ptr): Use element_type instead of _Tp.
* testsuite/20_util/shared_ptr/assign/auto_ptr_neg.cc: Adjust
dg-error pattern.
* testsuite/20_util/shared_ptr/cons/auto_ptr.cc: Test conversions.
* testsuite/20_util/shared_ptr/cons/unique_ptr.cc: Likewise.
* testsuite/20_util/shared_ptr/cons/void_neg.cc: Likewise.
* testsuite/20_util/shared_ptr/casts/reinterpret.cc: New test.
From-SVN: r241373
* include/backward/auto_ptr.h (__shared_ptr(auto_ptr&&)): Call
_M_enable_shared_from_this_with instead of
__enable_shared_from_this_helper.
* include/bits/shared_ptr.h (__enable_shared_from_this_helper):
Remove overload for std::enable_shared_from_this..
(__enable_shared_from_this_base): Define friend function to select a
std::enable_shared_from_this base class.
* include/bits/shared_ptr_base.h (__enable_shared_from_this_helper):
Remove all overloads.
(__shared_ptr): Change all relevant constructors to call
_M_enable_shared_from_this_with instead of
__enable_shared_from_this_helper.
(__shared_ptr::__efst_base_t, __shared_ptr::__has_efst_base): Helpers
to detect accessible and unambiguous enable_shared_from_this bases.
(__shared_ptr::_M_enable_shared_from_this_with): New function to
replace __enable_shared_from_this_helper overloads.
(__enable_shared_from_this_helper): Remove overload for
std::__enable_shared_from_this.
(__enable_shared_from_this_base): Define friend function to select a
std::__enable_shared_from_this base class.
* include/experimental/bits/shared_ptr.h (experimental::shared_ptr):
Change relevant constructors to call _M_enable_shared_from_this_with.
(experimental::shared_ptr::__efst_base_t)
(experimental::shared_ptr::__has_efst_base): Helpers to detect
accessible and unambiguous enable_shared_from_this bases.
(experimental::shared_ptr::_M_enable_shared_from_this_with): Define.
(experimental::__enable_shared_from_this_helper): Remove overload for
std::experimental::enable_shared_from_this.
(experimental::__expt_enable_shared_from_this_base): Define friend
function to select a std::experimental::enable_shared_from_this base.
* testsuite/experimental/memory/shared_ptr/cons/
enable_shared_from_this.cc: New test.
* testsuite/experimental/memory/shared_ptr/cons/unique_ptr_ctor.cc:
Adjust expected behaviour for shared_ptr<A[]>.
From-SVN: r241353
* include/bits/shared_ptr.h (_Assignable): New alias template.
(shared_ptr::operator=(const shared_ptr<_Tp1>&))
(shared_ptr::operator=(shared_ptr<_Tp1>&&))
(shared_ptr::operator=(unique_ptr<_Tp1>&&)): Constrain with
_Assignable.
* include/bits/shared_ptr_base.h (_Assignable): New alias template.
(__shared_ptr::operator=(const __shared_ptr<_Tp1>&))
(__shared_ptr::operator=(__shared_ptr<_Tp1>&&))
(__shared_ptr::operator=(unique_ptr<_Tp1>&&)): Constrain with
_Assignable.
(__shared_ptr::reset(_Tp1*), __shared_ptr::reset(_Tp1*, _Deleter))
(__shared_ptr::reset(_Tp1*, _Deleter, _Alloc)): Constrain with
_Convertible.
* testsuite/20_util/shared_ptr/cons/43820_neg.cc: Change dg-error to
match on any line.
* testsuite/20_util/shared_ptr/cons/void_neg.cc: Likewise.
* testsuite/20_util/shared_ptr/assign/sfinae.cc: New test.
* testsuite/20_util/shared_ptr/assign/shared_ptr_neg.cc: Update
expected errors. Remove unnecessary code.
* testsuite/20_util/shared_ptr/modifiers/reset_sfinae.cc: New test.
From-SVN: r239898
* testsuite/20_util/enable_shared_from_this/members/reinit.cc: Use
effective target not dg-options. Move check for feature-test macro to:
* testsuite/20_util/enable_shared_from_this/members/weak_from_this.cc:
New test.
From-SVN: r239121
* include/bits/shared_ptr_base.h (__cpp_lib_enable_shared_from_this):
Define feature-test macro.
* testsuite/20_util/enable_shared_from_this/members/reinit.cc: Test
for the macro.
From-SVN: r239094
* include/bits/shared_ptr.h (__enable_shared_from_this_helper): Use
nullptr.
* include/bits/shared_ptr_base.h (weak_ptr::_M_assign): Don't assign
if ownership is already shared with a shared_ptr object.
(__enable_shared_from_this_helper): Use nullptr.
* testsuite/20_util/enable_shared_from_this/members/const.cc: New.
* testsuite/20_util/enable_shared_from_this/members/reinit.cc: New.
* testsuite/20_util/enable_shared_from_this/requirements/
explicit_instantiation.cc: Instantiate with const and incomplete types.
From-SVN: r227232
