Date: Fri, 31 May 2024 22:28:48 +0000 From: bugzilla-noreply@freebsd.org To: toolchain@FreeBSD.org Subject: [Bug 279443] LIBCPP assertions are enabled in optimized builds when -DNDEBUG is given to clang Message-ID: <bug-279443-29464-CPjtAaJhEI@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-279443-29464@https.bugs.freebsd.org/bugzilla/> References: <bug-279443-29464@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D279443 Mark Millard <marklmi26-fbsd@yahoo.com> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |marklmi26-fbsd@yahoo.com --- Comment #1 from Mark Millard <marklmi26-fbsd@yahoo.com> --- I tried the code that is based on: std::copy( &buf[0], &buf[cb], // !!! ASSERTs HERE !!! std::back_inserter(r) ); via: # c++ -g get_executable_filename.cpp # gdb a.out . . . Reading symbols from a.out... (gdb) run Starting program: /usr/home/root/c_tests/a.out=20 Program received signal SIGILL, Illegal instruction. Privileged opcode. 0x0000000000203faa in std::__1::vector<char, std::__1::allocator<char> >::operator[][abi:se180100](unsigned long) (this=3D0x7fffffffe940, __n=3D29= ) at /usr/include/c++/v1/vector:1393 1393 _LIBCPP_ASSERT_VALID_ELEMENT_ACCESS(__n < size(), "vector[] index= out of bounds"); Then I tried that sequence based on: std::copy( &buf[0], //&buf[cb], // !!! ASSERTs HERE !!! &buf[0] + cb,=20 std::back_inserter(r) ); # c++ -g get_executable_filename.cpp # gdb a.out . . . Reading symbols from a.out... (gdb) run Starting program: /usr/home/root/c_tests/a.out=20 /usr/home/root/c_tests/a.out [Inferior 1 (process 66199) exited normally] I'm not so sure that C++ defines &buf[cb] as equivalent to &buf[0] + cb for std::contiguous_iterator contexts relative to all issues. cppreference.com reports for std::contiguous_iterator : QUOTE Semantic requirements Let a and b be dereferenceable iterators and c be a non-dereferenceable iterator of type I such that b is reachable from a and c is reachable from = b. The type I models contiguous_iterator only if all the concepts it subsumes = are modeled and: std::to_address(a) =3D=3D std::addressof(*a), std::to_address(b) =3D=3D std::to_address(a) + std::iter_difference_t<I>(b = - a), and std::to_address(c) =3D=3D std::to_address(a) + std::iter_difference_t<I>(c = - a). END QUOTE &buf[0] + cb notation does avoid any suggestion of dereferencing buf[cb] at any stage. --=20 You are receiving this mail because: You are the assignee for the bug.=
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