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
```
