https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98761
Bug ID: 98761
Summary: [modules] use of a module causes SIGSEGV at runtime
Product: gcc
Version: 11.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: boris at kolpackov dot net
Target Milestone: ---
The attached executable catches SIGSEGV when built with a module:
$ g++ -std=c++2a -fmodules-ts -x c++ -c format.mxx
$ g++ -std=c++2a -fmodules-ts -x c++ -c driver.cxx
$ g++ -std=c++2a -fmodules-ts -o test driver.o format.o
$ ./test
Segmentation fault (core dumped)
$ gdb test core
(gdb) bt
#0 __memcpy_avx_unaligned () at
../sysdeps/x86_64/multiarch/memcpy-avx-unaligned.S:148
#1 0x0000000000402cc7 in std::char_traits<char>::copy(char*, char const*,
unsigned long) ()
#2 0x000000000040405c in std::__cxx11::basic_string<char,
std::char_traits<char>, std::allocator<char> >::_S_copy(char*, char const*,
unsigned long) ()
#3 0x0000000000403f72 in std::__cxx11::basic_string<char,
std::char_traits<char>, std::allocator<char> >::_S_copy_chars(char*, char
const*, char const*) ()
#4 0x00000000004039b0 in void std::__cxx11::basic_string<char,
std::char_traits<char>, std::allocator<char> >::_M_construct<char const*>(char
const*, char const*, std::forward_iterator_tag) ()
#5 0x0000000000403635 in void std::__cxx11::basic_string<char,
std::char_traits<char>, std::allocator<char> >::_M_construct_aux<char
const*>(char const*, char const*, std::__false_type)
()
#6 0x0000000000403337 in void std::__cxx11::basic_string<char,
std::char_traits<char>, std::allocator<char> >::_M_construct<char const*>(char
const*, char const*) ()
#7 0x0000000000403072 in std::__cxx11::basic_string<char,
std::char_traits<char>, std::allocator<char> >::basic_string(char const*,
unsigned long, std::allocator<char> const&) ()
#8 0x00000000004033fc in std::__cxx11::basic_string<char,
std::char_traits<char>, std::allocator<char>
>::basic_string(std::__cxx11::basic_string<char, std::char_traits<char>,
std::allocator<char> >::__sv_wrapper, std::allocator<char> const&) ()
#9 0x00000000004030ef in std::__cxx11::basic_string<char,
std::char_traits<char>, std::allocator<char>
>::basic_string<std::basic_string_view<char, std::char_traits<char> >,
void>(std::basic_string_view<char, std::char_traits<char> > const&,
std::allocator<char> const&) ()
#10 0x000000000040266b in
hello::format_hello[abi:cxx11](std::basic_string_view<char,
std::char_traits<char> > const&) ()
#11 0x00000000004020be in main ()
The same code works fine if I get rid of the module. Re-ordering the object
files during linking also helps:
$ g++ -std=c++2a -fmodules-ts -o test format.o driver.o
