[gcc r17-2482] c++: Implement C++29 P3424R2 - Deallocation Functions with Throwing Exception Specification Are Ill-
Jakub Jelinek via Gcc-cvs <[email protected]>
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https://gcc.gnu.org/g:57ecb9897a096418ec3335bc0d18ec590e100396 commit r17-2482-g57ecb9897a096418ec3335bc0d18ec590e100396 Author: Jakub Jelinek <[email protected]> Date: Fri Jul 17 09:58:00 2026 +0200 c++: Implement C++29 P3424R2 - Deallocation Functions with Throwing Exception Specification Are Ill-formed [PR125833] The following patch attempts to implement the C++29 P3424R2 Deallocation Functions with Throwing Exception Specification Are Ill-formed paper by diagnosing those cases in grokfndecl, maybe_instantiate_noexcept and cp_parser_class_specifier. 2026-07-17 Jakub Jelinek <[email protected]> PR c++/125833 * cp-tree.h: Implement C++29 P3424R2 - Deallocation Functions with Throwing Exception Specification Are Ill-formed. (maybe_diagnose_deallocation_noexcept_false): Declare. * decl.cc (maybe_diagnose_deallocation_noexcept_false): New function. (grokfndecl): Call it. * pt.cc (maybe_instantiate_noexcept): Likewise. * parser.cc (cp_parser_class_specifier): Likewise. * g++.dg/cpp0x/dealloc2.C: Expect extra diagnostics in C++29. * g++.dg/cpp29/dealloc1.C: New test. Reviewed-by: Jason Merrill <[email protected]> Diff: --- gcc/cp/cp-tree.h | 1 + gcc/cp/decl.cc | 23 ++++++++++++++++++ gcc/cp/parser.cc | 4 ++++ gcc/cp/pt.cc | 4 ++++ gcc/testsuite/g++.dg/cpp0x/dealloc2.C | 3 ++- gcc/testsuite/g++.dg/cpp29/dealloc1.C | 45 +++++++++++++++++++++++++++++++++++ 6 files changed, 79 insertions(+), 1 deletion(-) diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h index 9271209ba2eb..c73b42ed44ff 100644 --- a/gcc/cp/cp-tree.h +++ b/gcc/cp/cp-tree.h @@ -7651,6 +7651,7 @@ extern tree start_decl (const cp_declarator *, cp_decl_specifier_seq *, int, extern void start_decl_1 (tree, bool); extern bool check_array_initializer (tree, tree, tree); extern void omp_declare_variant_finalize (tree, tree); +extern void maybe_diagnose_deallocation_noexcept_false (tree); struct cp_decomp { tree decl; unsigned int count; }; extern void cp_finish_decl (tree, tree, bool, tree, int, cp_decomp * = nullptr); extern tree lookup_decomp_type (tree); diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc index d10290752e7b..639eb85c0760 100644 --- a/gcc/cp/decl.cc +++ b/gcc/cp/decl.cc @@ -9430,6 +9430,25 @@ omp_declare_variant_finalize (tree decl, tree attr) } } +/* [basic.stc.dynamic.deallocation]/3 - A deallocation function shall not + have a potentially throwing exception specification. */ + +void +maybe_diagnose_deallocation_noexcept_false (tree decl) +{ + if (cxx_dialect >= cxx29 + && DECL_NAME (decl) + && IDENTIFIER_NEWDEL_OP_P (DECL_NAME (decl)) + && !IDENTIFIER_NEW_OP_P (DECL_NAME (decl))) + { + tree spec = TYPE_RAISES_EXCEPTIONS (TREE_TYPE (decl)); + if (spec && spec == noexcept_false_spec) + error_at (DECL_SOURCE_LOCATION (decl), + "deallocation function %qD declared possibly throwing", + decl); + } +} + static void cp_maybe_mangle_decomp (tree, cp_decomp *); /* Finish processing of a declaration; @@ -12621,6 +12640,10 @@ grokfndecl (tree ctype, } } + /* [basic.stc.dynamic.deallocation]/3 - A deallocation function shall not + have a potentially throwing exception specification. */ + maybe_diagnose_deallocation_noexcept_false (decl); + /* Caller will do the rest of this. */ if (check < 0) { diff --git a/gcc/cp/parser.cc b/gcc/cp/parser.cc index f455092b989e..3f042bec1c66 100644 --- a/gcc/cp/parser.cc +++ b/gcc/cp/parser.cc @@ -30135,6 +30135,10 @@ cp_parser_class_specifier (cp_parser* parser) /* Remove any template parameters from the symbol table. */ maybe_end_member_template_processing (); + + /* [basic.stc.dynamic.deallocation]/3 - A deallocation function + shall not have a potentially throwing exception specification. */ + maybe_diagnose_deallocation_noexcept_false (decl); } vec_safe_truncate (unparsed_noexcepts, 0); diff --git a/gcc/cp/pt.cc b/gcc/cp/pt.cc index 1fe94a863102..1290db45e182 100644 --- a/gcc/cp/pt.cc +++ b/gcc/cp/pt.cc @@ -28802,6 +28802,10 @@ maybe_instantiate_noexcept (tree fn, tsubst_flags_t complain) if (orig_fn) TREE_TYPE (orig_fn) = TREE_TYPE (fn); + /* [basic.stc.dynamic.deallocation]/3 - A deallocation function shall not + have a potentially throwing exception specification. */ + maybe_diagnose_deallocation_noexcept_false (fn); + return true; } diff --git a/gcc/testsuite/g++.dg/cpp0x/dealloc2.C b/gcc/testsuite/g++.dg/cpp0x/dealloc2.C index 5a0a89257b7a..75b833382e98 100644 --- a/gcc/testsuite/g++.dg/cpp0x/dealloc2.C +++ b/gcc/testsuite/g++.dg/cpp0x/dealloc2.C @@ -3,6 +3,7 @@ struct A {}; void operator delete (void *, A); void operator delete (void *, A) noexcept (false); // { dg-error "declaration of 'void operator delete\\\(void\\\*, A\\\) noexcept \\\(false\\\)' has a different exception specifier" } +// { dg-error "deallocation function 'void operator delete\\\(void\\\*, A\\\)' declared possibly throwing" "" { target c++29 } .-1 } struct B {}; -void operator delete (void *, B) noexcept (false); +void operator delete (void *, B) noexcept (false); // { dg-error "deallocation function 'void operator delete\\\(void\\\*, B\\\)' declared possibly throwing" "" { target c++29 } } void operator delete (void *, B); // { dg-error "declaration of 'void operator delete\\\(void\\\*, B\\\) noexcept' has a different exception specifier" } diff --git a/gcc/testsuite/g++.dg/cpp29/dealloc1.C b/gcc/testsuite/g++.dg/cpp29/dealloc1.C new file mode 100644 index 000000000000..cf39a68830d9 --- /dev/null +++ b/gcc/testsuite/g++.dg/cpp29/dealloc1.C @@ -0,0 +1,45 @@ +// P3424R2 - Deallocation Functions with Throwing Exception Specification Are Ill-formed +// { dg-do compile { target c++11 } } + +struct A {}; +struct B {}; +void operator delete (void *, A) noexcept (false); // { dg-error "deallocation function 'void operator delete\\\(void\\\*, A\\\)' declared possibly throwing" "" { target c++29 } } +void operator delete (void *, B) noexcept (false) {} // { dg-error "deallocation function 'void operator delete\\\(void\\\*, B\\\)' declared possibly throwing" "" { target c++29 } } +void operator delete[] (void *, A) noexcept (false); // { dg-error "deallocation function 'void operator delete \\\[\\\]\\\(void\\\*, A\\\)' declared possibly throwing" "" { target c++29 } } +void operator delete[] (void *, B) noexcept (false) {} // { dg-error "deallocation function 'void operator delete \\\[\\\]\\\(void\\\*, B\\\)' declared possibly throwing" "" { target c++29 } } +template <bool T, bool U> +struct C { + static void operator delete (void *) noexcept (T); // { dg-error "deallocation function 'static void C<T, U>::operator delete\\\(void\\\*\\\) \\\[with bool T = false; bool U = true\\\]' declared possibly throwing" "" { target c++29 } } + static void operator delete[] (void *) noexcept (T); // { dg-error "deallocation function 'static void C<T, U>::operator delete \\\[\\\]\\\(void\\\*\\\) \\\[with bool T = false; bool U = true\\\]' declared possibly throwing" "" { target c++29 } } +}; +template <bool T, bool U> +struct D { + static void operator delete (void *) noexcept (T) {} // { dg-error "deallocation function 'static void D<T, U>::operator delete\\\(void\\\*\\\) \\\[with bool T = false; bool U = true\\\]' declared possibly throwing" "" { target c++29 } } + static void operator delete[] (void *) noexcept (T) {}// { dg-error "deallocation function 'static void D<T, U>::operator delete \\\[\\\]\\\(void\\\*\\\) \\\[with bool T = false; bool U = true\\\]' declared possibly throwing" "" { target c++29 } } +}; +C <false, false> a; +C <true, false> b; +D <false, false> c; +D <true, false> d; +auto e = &C <false, true>::operator delete; +auto f = &C <true, true>::operator delete; +auto g = &D <false, true>::operator delete; +auto h = &D <true, true>::operator delete; +auto i = &C <false, true>::operator delete[]; +auto j = &C <true, true>::operator delete[]; +auto k = &D <false, true>::operator delete[]; +auto l = &D <true, true>::operator delete[]; +struct E { + static void operator delete (void *) noexcept (C) {} // { dg-error "deallocation function 'static void E::operator delete\\\(void\\\*\\\)' declared possibly throwing" "" { target c++29 } } + static constexpr bool C = false; +}; +template <int N> +struct F { + static void operator delete (void *) noexcept (false); // { dg-error "deallocation function 'static void F<N>::operator delete\\\(void\\\*\\\)' declared possibly throwing" "" { target c++29 } } + static void operator delete[] (void *) noexcept (false); // { dg-error "deallocation function 'static void F<N>::operator delete \\\[\\\]\\\(void\\\*\\\)' declared possibly throwing" "" { target c++29 } } +}; +template <int N> +struct G { + static void operator delete (void *) noexcept (false) {} // { dg-error "deallocation function 'static void G<N>::operator delete\\\(void\\\*\\\)' declared possibly throwing" "" { target c++29 } } + static void operator delete[] (void *) noexcept (false) {} // { dg-error "deallocation function 'static void G<N>::operator delete \\\[\\\]\\\(void\\\*\\\)' declared possibly throwing" "" { target c++29 } } +};