{"id":2226190,"url":"http://patchwork.ozlabs.org/api/1.1/patches/2226190/?format=json","web_url":"http://patchwork.ozlabs.org/project/gcc/patch/bmm.hhub6eebc2.gcc.gcc-TEST.redi.13.1.2@forge-stage.sourceware.org/","project":{"id":17,"url":"http://patchwork.ozlabs.org/api/1.1/projects/17/?format=json","name":"GNU Compiler Collection","link_name":"gcc","list_id":"gcc-patches.gcc.gnu.org","list_email":"gcc-patches@gcc.gnu.org","web_url":null,"scm_url":null,"webscm_url":null},"msgid":"","date":"2026-04-22T10:23:07","name":"[v1,2/2] libstdc++: More user-friendly failed assertions from shared_ptr dereference","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"f94f265437812b37afef756d203bf15a5d9117d8","submitter":{"id":93210,"url":"http://patchwork.ozlabs.org/api/1.1/people/93210/?format=json","name":"Jonathan Wakely via Sourceware Forge","email":"forge-bot+redi@forge-stage.sourceware.org"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/gcc/patch/bmm.hhub6eebc2.gcc.gcc-TEST.redi.13.1.2@forge-stage.sourceware.org/mbox/","series":[{"id":500968,"url":"http://patchwork.ozlabs.org/api/1.1/series/500968/?format=json","web_url":"http://patchwork.ozlabs.org/project/gcc/list/?series=500968","date":"2026-04-22T10:23:05","name":"Better assertions from filesystem directory iterators and shared_ptr","version":1,"mbox":"http://patchwork.ozlabs.org/series/500968/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/2226190/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/2226190/checks/","tags":{},"headers":{"Return-Path":"","X-Original-To":["incoming@patchwork.ozlabs.org","gcc-patches@gcc.gnu.org"],"Delivered-To":["patchwork-incoming@legolas.ozlabs.org","gcc-patches@gcc.gnu.org"],"Authentication-Results":["legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=gcc.gnu.org\n (client-ip=38.145.34.32; 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server2.sourceware.org","From":"Jonathan Wakely via Sourceware Forge\n ","Date":"Wed, 22 Apr 2026 10:23:07 +0000","Subject":"[PATCH v1 2/2] libstdc++: More user-friendly failed assertions from\n shared_ptr dereference","To":"gcc-patches mailing list ","Message-ID":"\n ","X-Mailer":"batrachomyomachia","X-Pull-Request-Organization":"gcc","X-Pull-Request-Repository":"gcc-TEST","X-Pull-Request":"https://forge.sourceware.org/gcc/gcc-TEST/pulls/13","References":"\n ","In-Reply-To":"\n ","X-Patch-URL":"\n https://forge.sourceware.org/redi/gcc/commit/4b66a15c10522168996049f2f7ec1392917bc82d","X-BeenThere":"gcc-patches@gcc.gnu.org","X-Mailman-Version":"2.1.30","Precedence":"list","List-Id":"Gcc-patches mailing list ","List-Unsubscribe":",\n ","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n ","Reply-To":"gcc-patches mailing list , redi@gcc.gnu.org","Errors-To":"gcc-patches-bounces~incoming=patchwork.ozlabs.org@gcc.gnu.org"},"content":"From: Jonathan Wakely \n\nCurrently dereferencing an empty shared_ptr prints a complicated\ninternal type in the assertion message:\n\ninclude/bits/shared_ptr_base.h:1377: std::__shared_ptr_access<_Tp, _Lp, , >::element_type& std::__shared_ptr_access<_Tp, _Lp, , >::operator*() const [with _Tp = std::filesystem::__cxx11::recursive_directory_iterator::_Dir_stack; __gnu_cxx::_Lock_policy _Lp = __gnu_cxx::_S_atomic; bool = false; bool = false; element_type = std::filesystem::__cxx11::recursive_directory_iterator::_Dir_stack]: Assertion '_M_get() != nullptr' failed.\n\nUsers don't care about any of the _Lp and template\nparameters, so this is unnecessarily verbose.\n\nWe can simplify it to something that only mentions \"shared_ptr_deref\"\nand the element type:\n\ninclude/bits/shared_ptr_base.h:1371: _Tp* std::__shared_ptr_deref(_Tp*) [with _Tp = filesystem::__cxx11::recursive_directory_iterator::_Dir_stack]: Assertion '__p != nullptr' failed.\n\nlibstdc++-v3/ChangeLog:\n\n\t* include/bits/shared_ptr_base.h (__shared_ptr_deref): New\n\tfunction template.\n\t(__shared_ptr_access, __shared_ptr_access<>): Use it.\n---\n libstdc++-v3/include/bits/shared_ptr_base.h | 28 +++++++++++++--------\n 1 file changed, 17 insertions(+), 11 deletions(-)","diff":"diff --git a/libstdc++-v3/include/bits/shared_ptr_base.h b/libstdc++-v3/include/bits/shared_ptr_base.h\nindex 9a7617e7014f..ee01594ce0c5 100644\n--- a/libstdc++-v3/include/bits/shared_ptr_base.h\n+++ b/libstdc++-v3/include/bits/shared_ptr_base.h\n@@ -1337,6 +1337,15 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n { };\n \n \n+ template\n+ [[__gnu__::__always_inline__]]\n+ inline _Tp*\n+ __shared_ptr_deref(_Tp* __p)\n+ {\n+ __glibcxx_assert(__p != nullptr);\n+ return __p;\n+ }\n+\n // Define operator* and operator-> for shared_ptr.\n template::value, bool = is_void<_Tp>::value>\n@@ -1347,10 +1356,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n \n element_type&\n operator*() const noexcept\n- {\n-\t__glibcxx_assert(_M_get() != nullptr);\n-\treturn *_M_get();\n- }\n+ { return *std::__shared_ptr_deref(_M_get()); }\n \n element_type*\n operator->() const noexcept\n@@ -1392,10 +1398,7 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n [[__deprecated__(\"shared_ptr::operator* is absent from C++17\")]]\n element_type&\n operator*() const noexcept\n- {\n-\t__glibcxx_assert(_M_get() != nullptr);\n-\treturn *_M_get();\n- }\n+ { return *std::__shared_ptr_deref(_M_get()); }\n \n [[__deprecated__(\"shared_ptr::operator-> is absent from C++17\")]]\n element_type*\n@@ -1406,13 +1409,16 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION\n }\n #endif\n \n+#pragma GCC diagnostic push\n+#pragma GCC diagnostic ignored \"-Wc++17-extensions\"\n element_type&\n operator[](ptrdiff_t __i) const noexcept\n {\n-\t__glibcxx_assert(_M_get() != nullptr);\n-\t__glibcxx_assert(!extent<_Tp>::value || __i < extent<_Tp>::value);\n-\treturn _M_get()[__i];\n+\tif constexpr (extent<_Tp>::value)\n+\t __glibcxx_assert(__i < extent<_Tp>::value);\n+\treturn std::__shared_ptr_deref(_M_get())[__i];\n }\n+#pragma GCC diagnostic pop\n \n private:\n element_type*\n","prefixes":["v1","2/2"]}