As mentioned in
https://gcc.gnu.org/pipermail/gcc-patches/2026-January/704712.html
in the gnu::constexpr_only thread, gnu::gnu_inline attribute actually
seems to work for most of what we need for C++26 constexpr exceptions
(i.e. when we want out of line bodies for C++ < 26 and need to use
constexpr for C++26, yet don't want for reasons mentioned in those
two PRs the bodies of those constexpr methods to be emitted inline).
Unfortunately clang++ doesn't handle it 100% properly and requires
the redundant inline keyword to make it work (even when the methods
are constexpr and thus implicilty inline), g++ doesn't require that,
so the patch adds also the redundant inline keywords and not just
the [[__gnu__::__gnu_inline__]] attribute.
This way if something wants to inline those functions it can, but
if their address is taken, we just rely on libstdc++.{so,a} to provide
those (which it does as before because those TUs are compiled with
older -std= modes).
The earlier r16-6477-gd5743234731 commit made sure gnu::gnu_inline
constexpr virtual methods can be key methods, so vtables and rtti can
be emitted only in the TU defining non-gnu_inline versions of those.
2026-01-07 Jakub Jelinek <jakub@redhat.com>
PR libstdc++/123183
PR libstdc++/123326
* libsupc++/exception (std::bad_exception::~bad_exception(),
std::bad_exception::what()): Add inline keyword and
[[__gnu__::__gnu_inline__]] attribute to the C++26 constexpr
exceptions definitions.
* libsupc++/exception.h (std::exception::~exception(),
std::exception::what()): Likewise.
* libsupc++/exception_ptr.h (std::exception_ptr::exception_ptr(void*)):
Likewise.
* libsupc++/nested_exception.h
(std::nested_exception::~nested_exception()): Likewise.
* libsupc++/typeinfo (std::bad_cast::~bad_cast(),
std::bad_cast::what(), std::bad_typeid::~bad_typeid(),
std::bad_typeid::what()): Likewise.
* include/bits/new_except.h (std::bad_alloc::~bad_alloc(),
std::bad_alloc::what(),
std::bad_array_new_length::~bad_array_new_length(),
std::bad_array_new_length::what()): Likewise.
* include/bits/stdexcept_except.h
(std::logic_error::logic_error(const string&),
std::logic_error::logic_error(const char*),
std::logic_error::~logic_error(), std::logic_error::what(),
std::domain_error::domain_error(const string&),
std::domain_error::domain_error(const char*),
std::invalid_argument::invalid_argument(const string&),
std::invalid_argument::invalid_argument(const char*),
std::length_error::length_error(const string&),
std::length_error::length_error(const char*),
std::out_of_range::out_of_range(const string&),
std::out_of_range::out_of_range(const char*),
std::runtime_error::runtime_error(const string&),
std::runtime_error::runtime_error(const char*),
std::runtime_error::~runtime_error(), std::runtime_error::what(),
std::overflow_error::overflow_error(const string&),
std::overflow_error::overflow_error(const char*),
std::overflow_error::~overflow_error(),
std::underflow_error::underflow_error(const string&),
std::underflow_error::underflow_error(const char*),
std::underflow_error::~underflow_error()): Likewise.
(std::domain_error::~domain_error(),
std::invalid_argument::~invalid_argument(),
std::length_error::~length_error(),
std::out_of_range::~out_of_range()): Likewise. Also change
_GLIBCXX_NOTHROW to noexcept on those definitions.
Since the implementation namespaces __detail and __exception_ptr aren't
exported from std, ADL can't find these functions there. Adding friend
declarations makes it work.
libstdc++-v3/ChangeLog:
* include/bits/quoted_string.h: Add ADL friends.
* libsupc++/exception_ptr.h: Add ADL friend.
The if-consteval branches in std::make_exception_ptr and
std::exception_ptr_cast use a try-catch block, which gives an error for
-fno-exceptions. Just make them return a null pointer at compile-time
when -fno-exceptions is used, because there's no way to get an active
exception with -fno-exceptions.
For both functions we have a runtime-only branch that depends on RTTI,
and a fallback using try-catch which works for runtime and consteval.
Rearrange both functions to express this logic more clearly.
Also adjust some formatting and whitespace elsewhere in the file.
libstdc++-v3/ChangeLog:
* libsupc++/exception_ptr.h (make_exception_ptr): Return null
for consteval when -fno-exceptions is used.
(exception_ptr_cast): Likewise. Allow consteval path to work
with -fno-rtti.
Reviewed-by: Jakub Jelinek <jakub@redhat.com>
The following patch makes std::exception_ptr_cast constexpr.
The paper suggests using dynamic_cast, but that does only work for
polymorphic exceptions, doesn't work if they are scalar or non-polymorphic
classes.
Furthermore, the patch adds some static_asserts for
"Mandates: E is a cv-unqualified complete object type. E is not an array type.
E is not a pointer or pointer-to-member type."
2025-07-11 Jakub Jelinek <jakub@redhat.com>
* libsupc++/exception_ptr.h: Implement C++26 P3748R0 - Inspecting
exception_ptr should be constexpr.
(std::exception_ptr_cast): Make constexpr, remove inline keyword. Add
static_asserts for Mandates. For if consteval use std::rethrow_exception,
catch it and return its address or nullptr.
* testsuite/18_support/exception_ptr/exception_ptr_cast.cc (E::~E): Add
constexpr.
(G::G): Likewise.
(test01): Likewise. Return bool and take bool argument, throw if the
argument is true. Add static_assert(test01(false)).
(main): Call test01(true) in try.
The following patch implements the C++26 P3068R5 - constexpr exceptions
paper.
As the IL cxx_eval_constant* functions process already contains the low
level calls like __cxa_{allocate,free}_exception, __cxa_{,re}throw etc.,
the patch just makes 10 extern "C" __cxa_* functions magic builtins which
during constant evaluation pretend to be constexpr even when not declared
so and handle them directly, plus does the same for 3 std namespace
functions - std::uncaught_exceptions, std::current_exception and
std::rethrow_exception and adds one new FE builtin -
__builtin_eh_ptr_adjust_ref which the library can use instead of the
_M_addref and _M_release out of line methods (this one instead of
recognizing _M_* as magic too because those are clearly specific to
libstdc++ and e.g. libc++ could use something else).
The patch uses magic VAR_DECLs with heap_{uninit_,,deleted_}identifier
DECL_NAME like for operator new/delete for objects allocated with
__cxa_allocate_exception, just sets their DECL_LANG_SPECIFIC so that
we can track their reference count as well (with std::exception_ptr
the same exception object can be referenced multiple times and we want
to destruct and free only when it reaches zero refcount).
For uncaught exceptions being propagated, the patch uses new kind of
*jump_target, which is that magic VAR_DECL described above.
The largest change in the patch is making jump_target argument non-optional
in cxa_eval_constant_exception and all functions it calls that need it.
This is because exceptions can be thrown from pretty much everywhere, e.g.
binary expression can throw in either operand. And the patch also adds
if (*jump_target) return NULL_TREE; or similar in many spots, so that we
don't crash because cxx_eval_constant_expression returned NULL_TREE
somewhere before actually trying to use it and so that we don't uselessly
dive into other operands etc.
Note, with statement expressions actually this was something we just didn't
handle correctly before, one can validly have:
a = ({ if (x) return 42; 12; }) + b;
or in the other operand, or break/continue instead of return if it is
somewhere in a loop/switch; and it isn't ok to branch from one operand to
another one through some kind of goto.
On the potential_constant_expression_1 side, important change was to
set *jump_target conservatively on calls that could throw for C++26 (the
patch uses magic void_node for potential_constant_expression* instead of
VAR_DECL, so that we don't have to create new VAR_DECLs there uselessly).
Without that change, several methods in libstdc++ wouldn't work correctly.
I'm not sure what exactly potential_constant_expression_1 maps to in the
C++26 standard wording now and whether doing that is ok, because basically
after the first call to non-noexcept function it stops checking stuff.
And, in some spots where I know potential_constant_expression_1 didn't
check some subexpressions (e.g. the EH only cleanups or TRY_BLOCK handlers)
I've added *potential_constant_expression* calls during cxx_eval_constant*,
not sure if I need to do that because potential_constant_expression_1 is
very conservative and just doesn't recurse on subexpressions in many cases.
2025-07-10 Jakub Jelinek <jakub@redhat.com>
PR c++/117785
gcc/c-family/
* c-cppbuiltin.cc (c_cpp_builtins): Predefine
__cpp_constexpr_exceptions=202411L for C++26.
gcc/cp/
* constexpr.cc: Implement C++26 P3068R5 - constexpr exceptions.
(class constexpr_global_ctx): Add caught_exceptions and
uncaught_exceptions members.
(constexpr_global_ctx::constexpr_global_ctx): Initialize
uncaught_exceptions.
(returns, breaks, continues, switches): Move earlier.
(throws): New function.
(exception_what_str, diagnose_std_terminate,
diagnose_uncaught_exception): New functions.
(enum cxa_builtin): New type.
(cxx_cxa_builtin_fn_p, cxx_eval_cxa_builtin_fn): New functions.
(cxx_eval_builtin_function_call): Add jump_target argument. Call
cxx_eval_cxa_builtin_fn for __builtin_eh_ptr_adjust_ref. Adjust
cxx_eval_constant_expression calls, if it results in jmp_target,
set *jump_target to it and return.
(cxx_bind_parameters_in_call): Add jump_target argument. Pass
it through to cxx_eval_constant_expression. If it sets *jump_target,
break.
(fold_operand): Adjust cxx_eval_constant_expression caller.
(cxx_eval_assert): Likewise. If it set jmp_target, return true.
(cxx_eval_internal_function): Add jump_target argument. Pass it
through to cxx_eval_constant_expression. Return early if *jump_target
after recursing on args.
(cxx_eval_dynamic_cast_fn): Likewise. Don't set reference_p for
C++26 with -fexceptions.
(cxx_eval_thunk_call): Add jump_target argument. Pass it through
to cxx_eval_constant_expression.
(cxx_set_object_constness): Likewise. Don't set TREE_READONLY if
throws (jump_target).
(cxx_eval_call_expression): Add jump_target argument. Pass it
through to cxx_eval_internal_function, cxx_eval_builtin_function_call,
cxx_eval_thunk_call, cxx_eval_dynamic_cast_fn and
cxx_set_object_constness. Pass it through also
cxx_eval_constant_expression on arguments, cxx_bind_parameters_in_call
and cxx_fold_indirect_ref and for those cases return early
if *jump_target. Call cxx_eval_cxa_builtin_fn for cxx_cxa_builtin_fn_p
functions. For cxx_eval_constant_expression on body, pass address of
cleared jmp_target automatic variable, if it throws propagate
to *jump_target and make it non-cacheable. For C++26 don't diagnose
calls to non-constexpr functions before cxx_bind_parameters_in_call
could report some argument throwing an exception.
(cxx_eval_unary_expression): Add jump_target argument. Pass it
through to cxx_eval_constant_expression and return early
if *jump_target after the call.
(cxx_fold_pointer_plus_expression): Likewise.
(cxx_eval_binary_expression): Likewise and similarly for
cxx_fold_pointer_plus_expression call.
(cxx_eval_conditional_expression): Pass jump_target to
cxx_eval_constant_expression on first operand and return early
if *jump_target after the call.
(cxx_eval_vector_conditional_expression): Add jump_target argument.
Pass it through to cxx_eval_constant_expression for all 3 arguments
and return early if *jump_target after any of those calls.
(get_array_or_vector_nelts): Add jump_target argument. Pass it
through to cxx_eval_constant_expression.
(eval_and_check_array_index): Add jump_target argument. Pass it
through to cxx_eval_constant_expression calls and return early after
each of them if *jump_target.
(cxx_eval_array_reference): Likewise.
(cxx_eval_component_reference): Likewise.
(cxx_eval_bit_field_ref): Likewise.
(cxx_eval_bit_cast): Likewise. Assert CHECKING_P call doesn't
throw or return.
(cxx_eval_logical_expression): Add jump_target argument. Pass it
through to cxx_eval_constant_expression calls and return early after
each of them if *jump_target.
(cxx_eval_bare_aggregate): Likewise.
(cxx_eval_vec_init_1): Add jump_target argument. Pass it through
to cxx_eval_bare_aggregate and recursive call. Pass it through
to get_array_or_vector_nelts and cxx_eval_constant_expression
and return early after it if *jump_target.
(cxx_eval_vec_init): Add jump_target argument. Pass it through
to cxx_eval_constant_expression and cxx_eval_vec_init_1.
(cxx_union_active_member): Add jump_target argument. Pass it
through to cxx_eval_constant_expression and return early after it
if *jump_target.
(cxx_fold_indirect_ref_1): Add jump_target argument. Pass it
through to cxx_union_active_member and recursive calls.
(cxx_eval_indirect_ref): Add jump_target argument. Pass it through
to cxx_fold_indirect_ref_1 calls and to recursive call, in which
case return early after it if *jump_target.
(cxx_fold_indirect_ref): Add jump_target argument. Pass it through
to cxx_fold_indirect_ref and cxx_eval_constant_expression calls and
return early after those if *jump_target.
(cxx_eval_trinary_expression): Add jump_target argument. Pass it
through to cxx_eval_constant_expression calls and return early after
those if *jump_target.
(cxx_eval_store_expression): Add jump_target argument. Pass it
through to cxx_eval_constant_expression and eval_and_check_array_index
calls and return early after those if *jump_target.
(cxx_eval_increment_expression): Add jump_target argument. Pass it
through to cxx_eval_constant_expression calls and return early after
those if *jump_target.
(label_matches): Handle VAR_DECL case.
(cxx_eval_statement_list): Remove local_target variable and
!jump_target handling. Handle throws (jump_target) like returns or
breaks.
(cxx_eval_loop_expr): Remove local_target variable and !jump_target
handling. Pass it through to cxx_eval_constant_expression. Handle
throws (jump_target) like returns.
(cxx_eval_switch_expr): Pass jump_target through to
cxx_eval_constant_expression on cond, return early after it
if *jump_target.
(build_new_constexpr_heap_type): Add jump_target argument. Pass it
through to cxx_eval_constant_expression calls, return early after
those if *jump_target.
(merge_jump_target): New function.
(cxx_eval_constant_expression): Make jump_target argument no longer
defaulted, don't test jump_target for NULL. Pass jump_target
through to recursive calls, cxx_eval_call_expression,
cxx_eval_store_expression, cxx_eval_indirect_ref,
cxx_eval_unary_expression, cxx_eval_binary_expression,
cxx_eval_logical_expression, cxx_eval_array_reference,
cxx_eval_component_reference, cxx_eval_bit_field_ref,
cxx_eval_vector_conditional_expression, cxx_eval_bare_aggregate,
cxx_eval_vec_init, cxx_eval_trinary_expression, cxx_fold_indirect_ref,
build_new_constexpr_heap_type, cxx_eval_increment_expression,
cxx_eval_bit_cast and return earlyu after some of those
if *jump_target as needed.
(cxx_eval_constant_expression) <case TARGET_EXPR>: For C++26 push
also CLEANUP_EH_ONLY cleanups, with NULL_TREE marker after them.
(cxx_eval_constant_expression) <case RETURN_EXPR>: Don't
override *jump_target if throws (jump_target).
(cxx_eval_constant_expression) <case TRY_CATCH_EXPR, case TRY_BLOCK,
case MUST_NOT_THROW_EXPR, case TRY_FINALLY_EXPR, case CLEANUP_STMT>:
Handle C++26 constant expressions.
(cxx_eval_constant_expression) <case CLEANUP_POINT_EXPR>: For C++26
with throws (jump_target) evaluate the CLEANUP_EH_ONLY cleanups as
well, and if not throws (jump_target) skip those. Set *jump_target
if some of the cleanups threw.
(cxx_eval_constant_expression) <case THROW_EXPR>: Recurse on operand
for C++26.
(cxx_eval_outermost_constant_expr): Diagnose uncaught exceptions both
from main expression and cleanups, diagnose also
break/continue/returns from the main expression. Handle
CLEANUP_EH_ONLY cleanup markers. Don't diagnose mutable poison stuff
if non_constant_p. Use different diagnostics for non-deleted heap
allocations if they were allocated by __cxa_allocate_exception.
(callee_might_throw): New function.
(struct check_for_return_continue_data): Add could_throw field.
(check_for_return_continue): Handle AGGR_INIT_EXPR and CALL_EXPR and
set d->could_throw if they could throw.
(potential_constant_expression_1): For CALL_EXPR allow
cxx_dynamic_cast_fn_p calls. For C++26 set *jump_target to void_node
for calls that could throw. For C++26 if call to non-constexpr call
is seen, try to evaluate arguments first and if they could throw,
don't diagnose call to non-constexpr function nor return false.
Adjust check_for_return_continue_data initializers and
set *jump_target to void_node if data.could_throw_p. For C++26
recurse on THROW_EXPR argument. Add comment explaining TRY_BLOCK
handling with C++26 exceptions. Handle throws like returns in some
cases.
* cp-tree.h (MUST_NOT_THROW_NOEXCEPT_P, MUST_NOT_THROW_THROW_P,
MUST_NOT_THROW_CATCH_P, DECL_EXCEPTION_REFCOUNT): Define.
(DECL_LOCAL_DECL_P): Fix comment typo, VARIABLE_DECL -> VAR_DECL.
(enum cp_built_in_function): Add CP_BUILT_IN_EH_PTR_ADJUST_REF,
(handler_match_for_exception_type): Declare.
* call.cc (handler_match_for_exception_type): New function.
* except.cc (initialize_handler_parm): Set MUST_NOT_THROW_CATCH_P
on newly created MUST_NOT_THROW_EXPR.
(begin_eh_spec_block): Set MUST_NOT_THROW_NOEXCEPT_P.
(wrap_cleanups_r): Set MUST_NOT_THROW_THROW_P.
(build_throw): Add another TARGET_EXPR whose scope spans
until after the __cxa_throw call and copy pointer value from ptr
to it and use it in __cxa_throw argument.
* tree.cc (builtin_valid_in_constant_expr_p): Handle
CP_BUILT_IN_EH_PTR_ADJUST_REF.
* decl.cc (cxx_init_decl_processing): Initialize
__builtin_eh_ptr_adjust_ref FE builtin.
* pt.cc (tsubst_stmt) <case MUST_NOT_THROW_EXPR>: Copy the
MUST_NOT_THROW_NOEXCEPT_P, MUST_NOT_THROW_THROW_P and
MUST_NOT_THROW_CATCH_P flags.
* cp-gimplify.cc (cp_gimplify_expr) <case CALL_EXPR>: Error on
non-folded CP_BUILT_IN_EH_PTR_ADJUST_REF calls.
gcc/testsuite/
* g++.dg/cpp0x/constexpr-ellipsis2.C: Expect different diagnostics for
C++26.
* g++.dg/cpp0x/constexpr-throw.C: Likewise.
* g++.dg/cpp1y/constexpr-84192.C: Expect different diagnostics.
* g++.dg/cpp1y/constexpr-throw.C: Expect different diagnostics for
C++26.
* g++.dg/cpp1z/constexpr-asm-5.C: Likewise.
* g++.dg/cpp26/constexpr-eh1.C: New test.
* g++.dg/cpp26/constexpr-eh2.C: New test.
* g++.dg/cpp26/constexpr-eh3.C: New test.
* g++.dg/cpp26/constexpr-eh4.C: New test.
* g++.dg/cpp26/constexpr-eh5.C: New test.
* g++.dg/cpp26/constexpr-eh6.C: New test.
* g++.dg/cpp26/constexpr-eh7.C: New test.
* g++.dg/cpp26/constexpr-eh8.C: New test.
* g++.dg/cpp26/constexpr-eh9.C: New test.
* g++.dg/cpp26/constexpr-eh10.C: New test.
* g++.dg/cpp26/constexpr-eh11.C: New test.
* g++.dg/cpp26/constexpr-eh12.C: New test.
* g++.dg/cpp26/constexpr-eh13.C: New test.
* g++.dg/cpp26/constexpr-eh14.C: New test.
* g++.dg/cpp26/constexpr-eh15.C: New test.
* g++.dg/cpp26/feat-cxx26.C: Change formatting in __cpp_pack_indexing
and __cpp_pp_embed test. Add __cpp_constexpr_exceptions test.
* g++.dg/cpp26/static_assert1.C: Expect different diagnostics for
C++26.
* g++.dg/cpp2a/consteval34.C: Likewise.
* g++.dg/cpp2a/consteval-memfn1.C: Likewise.
* g++.dg/cpp2a/constexpr-dynamic4.C: For C++26 add std::exception and
std::bad_cast definitions and expect different diagnostics.
* g++.dg/cpp2a/constexpr-dynamic6.C: Likewise.
* g++.dg/cpp2a/constexpr-dynamic7.C: Likewise.
* g++.dg/cpp2a/constexpr-dynamic8.C: Likewise.
* g++.dg/cpp2a/constexpr-dynamic9.C: Likewise.
* g++.dg/cpp2a/constexpr-dynamic11.C: Likewise.
* g++.dg/cpp2a/constexpr-dynamic14.C: Likewise.
* g++.dg/cpp2a/constexpr-dynamic18.C: Likewise.
* g++.dg/cpp2a/constexpr-new27.C: New test.
* g++.dg/cpp2a/constexpr-typeid5.C: New test.
libstdc++-v3/
* include/bits/version.def (constexpr_exceptions): New.
* include/bits/version.h: Regenerate.
* libsupc++/exception (std::bad_exception::bad_exception): Add
_GLIBCXX26_CONSTEXPR.
(std::bad_exception::~bad_exception, std::bad_exception::what): For
C++26 add constexpr and define inline.
* libsupc++/exception.h (std::exception::exception,
std::exception::operator=): Add _GLIBCXX26_CONSTEXPR.
(std::exception::~exception, std::exception::what): For C++26 add
constexpr and define inline.
* libsupc++/exception_ptr.h (std::make_exception_ptr): Add
_GLIBCXX26_CONSTEXPR. For if consteval use just throw with
current_exception() in catch.
(std::exception_ptr::exception_ptr(void*)): For C++26 add constexpr
and define inline.
(std::exception_ptr::exception_ptr()): Add _GLIBCXX26_CONSTEXPR.
(std::exception_ptr::exception_ptr(const exception_ptr&)): Likewise.
Use __builtin_eh_ptr_adjust_ref if consteval and compiler has it
instead of _M_addref.
(std::exception_ptr::exception_ptr(nullptr_t)): Add
_GLIBCXX26_CONSTEXPR.
(std::exception_ptr::exception_ptr(exception_ptr&&)): Likewise.
(std::exception_ptr::operator=): Likewise.
(std::exception_ptr::~exception_ptr): Likewise. Use
__builtin_eh_ptr_adjust_ref if consteval and compiler has it
instead of _M_release.
(std::exception_ptr::swap): Add _GLIBCXX26_CONSTEXPR.
(std::exception_ptr::operator bool): Likewise.
(std::exception_ptr::operator==): Likewise.
* libsupc++/nested_exception.h
(std::nested_exception::nested_exception): Add _GLIBCXX26_CONSTEXPR.
(std::nested_exception::operator=): Likewise.
(std::nested_exception::~nested_exception): For C++26 add constexpr
and define inline.
(std::nested_exception::rethrow_if_nested): Add _GLIBCXX26_CONSTEXPR.
(std::nested_exception::nested_ptr): Likewise.
(std::_Nested_exception::_Nested_exception): Likewise.
(std::throw_with_nested, std::rethrow_if_nested): Likewise.
* libsupc++/new (std::bad_alloc::bad_alloc): Likewise.
(std::bad_alloc::operator=): Likewise.
(std::bad_alloc::~bad_alloc): For C++26 add constexpr and define
inline.
(std::bad_alloc::what): Likewise.
(std::bad_array_new_length::bad_array_new_length): Add
_GLIBCXX26_CONSTEXPR.
(std::bad_array_new_length::~bad_array_new_length): For C++26 add
constexpr and define inline.
(std::bad_array_new_length::what): Likewise.
* libsupc++/typeinfo (std::bad_cast::bad_cast): Add
_GLIBCXX26_CONSTEXPR.
(std::bad_cast::~bad_cast): For C++26 add constexpr and define inline.
(std::bad_cast::what): Likewise.
(std::bad_typeid::bad_typeid): Add _GLIBCXX26_CONSTEXPR.
(std::bad_typeid::~bad_typeid): For C++26 add constexpr and define
inline.
(std::bad_typeid::what): Likewise.
The following patch attempts to implement the C++26 P2927R3 - Inspecting exception_ptr
paper (but not including P3748R0, I plan to play with it incrementally and
it will really depend on the Constexpr exceptions patch).
The function template is implemented using an out of line private method of
exception_ptr, so that P3748R0 then can use if consteval and provide a
constant evaluation variant of it.
2025-06-26 Jakub Jelinek <jakub@redhat.com>
* include/bits/version.def (exception_ptr_cast): Add.
* include/bits/version.h: Regenerate.
* libsupc++/exception: Define __glibcxx_want_exception_ptr_cast before
including bits/version.h.
* libsupc++/exception_ptr.h (std::exception_ptr_cast): Define.
(std::__exception_ptr::exception_ptr::_M_exception_ptr_cast): Declare.
* libsupc++/eh_ptr.cc
(std::__exception_ptr::exception_ptr::_M_exception_ptr_cast): Define.
* src/c++23/std.cc.in (std::exception_ptr_cast): Export.
* config/abi/pre/gnu.ver: Export
_ZNKSt15__exception_ptr13exception_ptr21_M_exception_ptr_castERKSt9type_info
at CXXABI_1.3.17.
* testsuite/util/testsuite_abi.cc (check_version): Allow CXXABI_1.3.17.
* testsuite/18_support/exception_ptr/exception_ptr_cast.cc: New test.
Fix some problems noticed with -Wsystem-headers.
libstdc++-v3/ChangeLog:
* include/bits/stl_tempbuf.h (_Temporary_buffer): Disable
warnings about get_temporary_buffer being deprecated.
* include/ext/functional (mem_fun1, mem_fun1_ref): Disable
warnings about mem_fun1_t, const_mem_fun1_t, mem_fun1_ref_t and
const_mem_fun1_ref_t being deprecated.
* include/std/array (__array_traits<T, 0>): Remove artificial
attributes which give warnings about being ignored.
* include/std/spanstream (basic_spanbuf::setbuf): Add assertion
and adjust to avoid narrowing warning.
* libsupc++/exception_ptr.h [!__cpp_rtti && !__cpp_exceptions]
(make_exception_ptr): Add missing inline specifier.
The non-member swap for std::exception_ptr is in a nested namespace and
so can only be found by ADL currently. Add a using-declaration so that
qualified std::swap calls will use the std::exception_ptr::swap member,
instead of the generic std::swap.
There's no new test for this, because the generic std::swap works, it
just does more work than is necessary.
Also tell Doxygen to replace the __exception_ptr namespace with
"__unspecified__" in the generate docs, so the real name is not
documented.
libstdc++-v3/ChangeLog:
* doc/doxygen/user.cfg.in (PREDEFINED): Replace __exception_ptr
with "__unspecified__".
* libsupc++/exception_ptr.h: Improve doxygen docs.
(__exception_ptr::swap): Also declare in namespace std.
This allows std::make_exception_ptr to be used in a translation unit
compiled with -fno-exceptions. This works because the new implementation
added for PR 68297 doesn't need to throw or catch anything. The catch is
there to handle exceptions from the constructor of the exception object,
which we can assume won't happen in a -fno-exceptions TU and so use the
__catch macro instead. If the constructor does throw (because it's
defined in a different TU which was compiled with exceptions enabled)
then that exception will propagate to the make_exception_ptr caller.
That seems acceptable for a program that is trying to mix & match TUs
compiled with and without exceptions, and using types that throw when
constructed. That should be rare, and can't reasonably be expected to
have sensible behaviour.
This also enables the new implementation for targets that use a
non-standard calling convention for the exceptionDestructor callback
(specifically, mingw, which uses __thiscall). All we need to do is mark
the __dest_thunk function template with the right calling convention.
Finally, the useless no-op definition of make_exception_ptr (which is
only used if both RTTI and exceptions are disabled) is marked
always_inline, to ensure that the linker won't keep that definition and
discard the functional ones when both definitions of the function are
present in the link. An alternative would be to add the abi_tag
attribute to the useless definition, but making it always_inline should
work, and it's small enough to always be inlined reliably.
libstdc++-v3/ChangeLog:
PR libstdc++/85813
* libsupc++/exception_ptr.h (__dest_thunk): Add macro for
destructor calling convention.
(make_exception_ptr): Enable non-throwing implementation for
-fno-exceptions and for non-standard calling conventions. Use
always_inline attribute on the useless no-rtti no-exceptions
definition.
* testsuite/18_support/exception_ptr/64241.cc: Add -fno-rtti so
the no-op implementation is still used.
This restores support for std::make_exception_ptr<E&> and for using
std::exception_ptr in C++98.
Because the new non-throwing implementation needs to use std::decay to
handle references the original throwing implementation is used for
C++98.
We also need to change the typeid expression so it doesn't yield the
dynamic type when the function parameter is a reference to a polymorphic
type. Otherwise the new exception object could be caught by any handler
matching the dynamic type, even though the actual exception object is
only a copy of the base class, sliced to the static type.
libstdc++-v3/ChangeLog:
PR libstdc++/103630
* libsupc++/exception_ptr.h (exception_ptr): Fix exception
specifications on inline definitions.
(make_exception_ptr): Decay the template parameter. Use typeid
of the static type.
* testsuite/18_support/exception_ptr/103630.cc: New test.
The recent changes to define various std::exception_ptr functions inline
included a change so that the definitions of those functions would be
omitted for the ABI unstable gnu-versioned-namespace configuration. That
change was incorrect, because the existing functions that are gated by
the _GLIBCXX_EH_PTR_COMPAT macro are always needed even for the
versioned namespace.
This change introduces a new macro to control whether operator== is
defined as deleted or not, distinct from the existing macro. The new
macro is not defined for versioned namespace builds, but the old macro
still is.
libstdc++-v3/ChangeLog:
* libsupc++/eh_ptr.cc (_GLIBCXX_EH_PTR_RELOPS_COMPAT): Define
new macro.
* libsupc++/exception_ptr.h (_GLIBCXX_EH_PTR_USED): Check new
macro instead of _GLIBCXX_EH_PTR_COMPAT.
(operator==): Likewise.
With PR c++/67453 fixed we can rely on the 'used' attribute to emit
inline constructors and destructors in libsupc++/eh_ptr.cc. This means
we don't need to suppress the 'inline' keyword on them in that file, and
don't need to force 'always_inline' on them in other files.
libstdc++-v3/ChangeLog:
PR libstdc++/97729
* libsupc++/exception_ptr.h (exception_ptr::exception_ptr())
(exception_ptr::exception_ptr(const exception_ptr&))
(exception_ptr::~exception_ptr()): Remove 'always_inline'
attributes. Use 'inline' unconditionally.
This fixes some multiple definition errors caused by the changes for
PR libstdc++/90295. The previous solution for inlining the members of
std::exception_ptr but still exporting them from the library was to
suppress the 'inline' keyword on those functions when compiling
libsupc++/eh_ptr.cc, so they get defined in that file. That produces ODR
violations though, because there are now both inline and non-inline
definitions in the library, due to the use of std::exception_ptr in
other files sucg as src/c++11/future.cc.
The new solution is to define all the relevant members as 'inline'
unconditionally, but use __attribute__((used)) to cause definitions to
be emitted in libsupc++/eh_ptr.cc as before. This doesn't quite work
however, because PR c++/67453 means the attribute is ignored on
constructors and destructors. As a workaround, the old solution
(conditionally inline) is still used for those members, but they are
given the always_inline attribute so that they aren't emitted in
src/c++11/future.o as inline definitions.
libstdc++-v3/ChangeLog:
PR libstdc++/97729
* include/std/future (__basic_future::_M_get_result): Use
nullptr for null pointer constant.
* libsupc++/eh_ptr.cc (operator==, operator!=): Remove
definitions.
* libsupc++/exception_ptr.h (_GLIBCXX_EH_PTR_USED): Define
macro to conditionally add __attribute__((__used__)).
(operator==, operator!=, exception_ptr::exception_ptr())
(exception_ptr::exception_ptr(const exception_ptr&))
(exception_ptr::~exception_ptr())
(exception_ptr::operator=(const exception_ptr&))
(exception_ptr::swap(exception_ptr&)): Always define as
inline. Add macro to be conditionally "used".
My recent changes to std::exception_ptr moved some members to be inline
in the header but didn't replace the variable names with reserved names.
The "tmp" variable must be fixed. The "other" parameter is actually a
reserved name because of std::allocator<T>::rebind<U>::other but should
be fixed anyway.
There are also some bad uses of "ForwardIterator" in <ranges>.
There's also a "il" parameter in a std::seed_seq constructor in <random>
which is only reserved since C++14.
libstdc++-v3/ChangeLog:
* include/bits/random.h (seed_seq(initializer_list<T>)): Rename
parameter to use reserved name.
* include/bits/ranges_algo.h (shift_left, shift_right): Rename
template parameters to use reserved name.
* libsupc++/exception_ptr.h (exception_ptr): Likewise for
parameters and local variables.
* testsuite/17_intro/names.cc: Check "il". Do not check "d" and
"y" in C++20 mode.
This inlines most members of std::exception_ptr so that all operations
on a null exception_ptr can be optimized away. This benefits code like
std::future and coroutines where an exception_ptr object is present to
cope with exceptional cases, but is usually not used and remains null.
Since those functions were previously non-inline we have to continue to
export them from the library, for objects that were compiled against the
old headers and expect to find definitions in the library.
In order to inline the copy constructor and destructor we need to export
the _M_addref() and _M_release() members that increment/decrement the
reference count when copying/destroying a non-null exception_ptr. The
copy ctor and dtor check for null and don't call _M_addref and
_M_release unless they need to. The checks for null pointers in
_M_addref and _M_release are still needed because old code might call
them without checking for null first. But we can use __builtin_expect to
predict that they are usually called for the non-null case.
libstdc++-v3/ChangeLog:
PR libstdc++/90295
* config/abi/pre/gnu.ver (CXXABI_1.3.13): New symbol version.
(exception_ptr::_M_addref(), exception_ptr::_M_release()):
Export symbols.
* libsupc++/eh_ptr.cc (exception_ptr::exception_ptr()):
Remove out-of-line definition.
(exception_ptr::exception_ptr(const exception_ptr&)):
Likewise.
(exception_ptr::~exception_ptr()): Likewise.
(exception_ptr::operator=(const exception_ptr&)):
Likewise.
(exception_ptr::swap(exception_ptr&)): Likewise.
(exception_ptr::_M_addref()): Add branch prediction.
* libsupc++/exception_ptr.h (exception_ptr::operator bool):
Add noexcept.
[!_GLIBCXX_EH_PTR_COMPAT] (operator==, operator!=): Define
inline as hidden friends. Remove declarations at namespace
scope.
(exception_ptr::exception_ptr()): Define inline.
(exception_ptr::exception_ptr(const exception_ptr&)):
Likewise.
(exception_ptr::~exception_ptr()): Likewise.
(exception_ptr::operator=(const exception_ptr&)):
Likewise.
(exception_ptr::swap(exception_ptr&)): Likewise.
* testsuite/util/testsuite_abi.cc: Add CXXABI_1.3.13.
* testsuite/18_support/exception_ptr/90295.cc: New test.
PR libstdc++/85812
* libsupc++/cxxabi_init_exception.h (__cxa_free_exception): Declare.
* libsupc++/exception_ptr.h (make_exception_ptr) [__cpp_exceptions]:
Refactor to separate non-throwing and throwing implementations.
[__cpp_rtti && !_GLIBCXX_HAVE_CDTOR_CALLABI]: Deallocate the memory
if constructing the object throws.
From-SVN: r260323
exception_ptr.h needs the forward declaration because it's
included from <typeinfo> before <typeinfo> defines std::type_info.
Tested:
bootstrap + make check-c++ on x86_64.
libstdc++-v3/ChangeLog:
2011-03-31 Jeffrey Yasskin <jyasskin@google.com>
* libsupc++/exception_ptr.h: Forward-declare std::type_info.
* libsupc++/nested_exception.h (__throw_with_nested): Remove a
redundant default argument from std::__throw_with_nested.
From-SVN: r171807
Jakub Jelinek