https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115600
Bug ID: 115600 Summary: UndefinedBehaviorSanitizer doesn't seem to like modules Product: gcc Version: 14.1.1 Status: UNCONFIRMED Severity: normal Priority: P3 Component: c++ Assignee: unassigned at gcc dot gnu.org Reporter: cjdb.ns at gmail dot com Target Milestone: --- Created attachment 58498 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=58498&action=edit Preprocessed source ## GCC info ``` $ gcc --version gcc (GCC) 14.1.1 20240522 Copyright (C) 2024 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. ``` ## System type ``` $ lsb_release -a LSB Version: n/a Distributor ID: Arch Description: Arch Linux Release: rolling Codename: n/a ``` ## How GCC was configured/built Arch default ## Command line Original invocation ``` /usr/bin/g++ -fdiagnostics-color=always -fstack-protector-strong -fvisibility=hidden -Werror -pedantic -Wall -Wattributes -Wcast-align -Wconversion -Wdouble-promotion -Wextra -Wformat=2 -Wnon-virtual-dtor -Wnull-dereference -Wodr -Wold-style-cast -Woverloaded-virtual -Wshadow -Wsign-conversion -Wsign-promo -Wunused -Wno-ignored-attributes -Wno-cxx-attribute-extension -Wno-gnu-include-next -Wno-private-header -Wno-unused-command-line-argument -D_GLIBCXX_ASSERTIONS -fsanitize=address,undefined -g -std=gnu++23 -MD -MT source/module_interface/CMakeFiles/greeter_module.dir/greeter_module.cpp.o -MF source/module_interface/CMakeFiles/greeter_module.dir/greeter_module.cpp.o.d -fmodules-ts -fmodule-mapper=source/module_interface/CMakeFiles/greeter_module.dir/greeter_module.cpp.o.modmap -MD -fdeps-format=p1689r5 -x c++ -o source/module_interface/CMakeFiles/greeter_module.dir/greeter_module.cpp.o -c ~/projects/project-template-3/build/test/default-options/Output/gnu-toolchain.test.tmp/gnu_toolchain/source/module_interface/greeter_module.cpp ``` With some experimenting, I was able to minimise it to this. Note that the culprit is `-fsanitize=undefined`: it'll work fine without that (and with `-fsanitize=address`). ``` /usr/bin/g++ -fsanitize=undefined -std=gnu++23 -fmodules-ts -fmodule-mapper=source/module_interface/CMakeFiles/greeter_module.dir/greeter_module.cpp.o.modmap -MD -fdeps-format=p1689r5 -x c++ ~/projects/pr oject-template-3/build/test/default-options/Output/gnu-toolchain.test.tmp/gnu_toolchain/source/module_interface/greeter_module.cpp ``` ## Diagnostic ``` internal compiler error: in tree_node, at cp/module.cc:9428 4 | export module greeter; | ^~~~~~ 0x217b27a internal_error(char const*, ...) ???:0 0x703e87 fancy_abort(char const*, int, char const*) ???:0 0x8237da depset::hash::find_dependencies(module_state*) ???:0 0x829996 module_state::write_begin(elf_out*, cpp_reader*, module_state_config&, unsigned int&) ???:0 0x839c57 finish_module_processing(cpp_reader*) ???:0 0x7ccdfd c_parse_final_cleanups() ???:0 0x9c4fb2 c_common_parse_file() ???:0 ```