https://gcc.gnu.org/bugzilla/show_bug.cgi?id=119076
Bug ID: 119076
Summary: ICE with Segmentation fault if using PCH
Product: gcc
Version: 15.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: pch
Assignee: unassigned at gcc dot gnu.org
Reporter: trinxery at firemail dot cc
Target Milestone: ---
Shell to reproduce:
```
mkdir gccbug2
cd gccbug2
git clone --depth=1 'https://github.com/nlohmann/json'
cd json
mkdir build
cd build
cmake -DJSON_BuildTests=Off -DCMAKE_INSTALL_PREFIX=. ..
make -j
make install
echo '#include "./include/nlohmann/json.hpp"\n#include <iostream>\nint main() {
std::cout << nlohmann::json{}; }' > ./main.cxx
g++-15 -O0 -fmodules-ts './include/nlohmann/json.hpp' -std=c++20 -I'./include/'
g++-15 -v -save-temps -freport-bug -Winvalid-pch -O0 -fmodules-ts './main.cxx'
-std=c++20
```
(Is not reproducible without `-fmodules-ts`, or with g++-14 and g++-13, or
without precompiling `json.hpp`)
Output on machine with `gcc version 15.0.1 20250213 (experimental) [master
r15-7502-g26baa2c09b3] (Debian 15-20250213-1)`:
```
COLLECT_GCC=g++-15
COLLECT_LTO_WRAPPER=/usr/libexec/gcc/x86_64-linux-gnu/15/lto-wrapper
OFFLOAD_TARGET_NAMES=nvptx-none:amdgcn-amdhsa
OFFLOAD_TARGET_DEFAULT=1
Target: x86_64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Debian 15-20250213-1'
--with-bugurl=file:///usr/share/doc/gcc-15/README.Bugs
--enable-languages=c,ada,c++,go,d,fortran,objc,obj-c++,m2,rust,cobol
--prefix=/usr --with-gcc-major-version-only --program-suffix=-15
--program-prefix=x86_64-linux-gnu- --enable-shared --enable-linker-build-id
--libexecdir=/usr/libexec --without-included-gettext --enable-threads=posix
--libdir=/usr/lib --enable-nls --enable-clocale=gnu --enable-libstdcxx-debug
--enable-libstdcxx-time=yes --with-default-libstdcxx-abi=new
--enable-libstdcxx-backtrace --enable-gnu-unique-object --disable-vtable-verify
--enable-plugin --enable-default-pie --with-system-zlib
--enable-libphobos-checking=release --with-target-system-zlib=auto
--enable-objc-gc=auto --enable-multiarch --disable-werror --enable-cet
--with-arch-32=i686 --with-abi=m64 --with-multilib-list=m32,m64,mx32
--enable-multilib --with-tune=generic
--enable-offload-targets=nvptx-none=/build/reproducible-path/gcc-15-15-20250213/debian/tmp-nvptx/usr,amdgcn-amdhsa=/build/reproducible-path/gcc-15-15-20250213/debian/tmp-gcn/usr
--enable-offload-defaulted --without-cuda-driver
--enable-checking=yes,extra,rtl --build=x86_64-linux-gnu
--host=x86_64-linux-gnu --target=x86_64-linux-gnu
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 15.0.1 20250213 (experimental) [master r15-7502-g26baa2c09b3]
(Debian 15-20250213-1)
COLLECT_GCC_OPTIONS='-v' '-save-temps' '-freport-bug' '-Winvalid-pch' '-O0'
'-fmodules' '-std=c++20' '-foffload-options=-l_GCC_m' '-shared-libgcc'
'-mtune=generic' '-march=x86-64' '-dumpdir' 'a-'
/usr/libexec/gcc/x86_64-linux-gnu/15/cc1plus -E -quiet -v -imultiarch
x86_64-linux-gnu -D_GNU_SOURCE ./main.cxx -mtune=generic -march=x86-64
-std=c++20 -Winvalid-pch -freport-bug -fmodules -foffload-options=-l_GCC_m -O0
-fpch-preprocess -fasynchronous-unwind-tables -o a-main.ii
ignoring duplicate directory "/usr/include/x86_64-linux-gnu/c++/15"
ignoring nonexistent directory "/usr/local/include/x86_64-linux-gnu"
ignoring nonexistent directory
"/usr/lib/gcc/x86_64-linux-gnu/15/include-fixed/x86_64-linux-gnu"
ignoring nonexistent directory "/usr/lib/gcc/x86_64-linux-gnu/15/include-fixed"
ignoring nonexistent directory
"/usr/lib/gcc/x86_64-linux-gnu/15/../../../../x86_64-linux-gnu/include"
#include "..." search starts here:
#include <...> search starts here:
/usr/include/c++/15
/usr/include/x86_64-linux-gnu/c++/15
/usr/include/c++/15/backward
/usr/lib/gcc/x86_64-linux-gnu/15/include
/usr/local/include
/usr/include/x86_64-linux-gnu
/usr/include
End of search list.
COLLECT_GCC_OPTIONS='-v' '-save-temps' '-freport-bug' '-Winvalid-pch' '-O0'
'-fmodules' '-std=c++20' '-foffload-options=-l_GCC_m' '-shared-libgcc'
'-mtune=generic' '-march=x86-64' '-dumpdir' 'a-'
/usr/libexec/gcc/x86_64-linux-gnu/15/cc1plus -fpreprocessed a-main.ii -quiet
-dumpdir a- -dumpbase main.cxx -dumpbase-ext .cxx -mtune=generic -march=x86-64
-O0 -Winvalid-pch -std=c++20 -version -freport-bug -fmodules
-foffload-options=-l_GCC_m -fasynchronous-unwind-tables -o a-main.s
GNU C++20 (Debian 15-20250213-1) version 15.0.1 20250213 (experimental) [master
r15-7502-g26baa2c09b3] (x86_64-linux-gnu)
compiled by GNU C version 15.0.1 20250213 (experimental) [master
r15-7502-g26baa2c09b3], GMP version 6.3.0, MPFR version 4.2.1, MPC version
1.3.1, isl version isl-0.27-GMP
GGC heuristics: --param ggc-min-expand=30 --param ggc-min-heapsize=4096
Compiler executable checksum: 93a4481bddb607656af83a1985fd9568
In file included from ./include/nlohmann/json.hpp:60,
of module ././include/nlohmann/json.hpp, imported at ./main.cxx:1:
./include/nlohmann/detail/output/serializer.hpp: In instantiation of ‘static
uint8_t
nlohmann::json_abi_v3_11_3::detail::serializer<BasicJsonType>::decode(uint8_t&,
uint32_t&, uint8_t) [with BasicJsonType =
nlohmann::json_abi_v3_11_3::basic_json<>; uint8_t = unsigned char; uint32_t =
unsigned int]’:
./include/nlohmann/detail/output/serializer.hpp:405:27: required from ‘void
nlohmann::json_abi_v3_11_3::detail::serializer<BasicJsonType>::dump_escaped(const
string_t&, bool) [with BasicJsonType =
nlohmann::json_abi_v3_11_3::basic_json<>; string_t =
std::__cxx11::basic_string<char>]’
405 | switch (decode(state, codepoint, byte))
| ~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
./include/nlohmann/detail/output/serializer.hpp:140:25: required from ‘void
nlohmann::json_abi_v3_11_3::detail::serializer<BasicJsonType>::dump(const
BasicJsonType&, bool, bool, unsigned int, unsigned int) [with BasicJsonType =
nlohmann::json_abi_v3_11_3::basic_json<>]’
140 | dump_escaped(i->first, ensure_ascii);
| ^~~~~~~~~~~~
./include/nlohmann/json.hpp:4014:15: required from ‘std::ostream&
nlohmann::json_abi_v3_11_3::operator<<(std::ostream&, const basic_json<>&)’
4014 | s.dump(j, pretty_print, false, static_cast<unsigned
int>(indentation));
|
~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
./main.cxx:3:42: required from here
3 | int main() { std::cout << nlohmann::json{}; }
| ^
./include/nlohmann/detail/output/serializer.hpp:902:52: internal compiler
error: Segmentation fault
902 | static const std::array<std::uint8_t, 400> utf8d =
| ^~~~~
0x7f38e924564f ???
./signal/../sysdeps/unix/sysv/linux/x86_64/libc_sigaction.c:0
0x7f38e922a3b7 __libc_start_call_main
../sysdeps/nptl/libc_start_call_main.h:58
0x7f38e922a47a __libc_start_main_impl
../csu/libc-start.c:360
Please submit a full bug report, with preprocessed source.
Please include the complete backtrace with any bug report.
See <file:///usr/share/doc/gcc-15/README.Bugs> for instructions.
The bug is not reproducible, so it is likely a hardware or OS problem.
```
Output on another machine with `gcc version <same as above> (Ubuntu
15-20250213-1ubuntu1)`:
```
<...>
./include/nlohmann/detail/output/serializer.hpp:902:52: internal compiler
error: Segmentation fault
902 | static const std::array<std::uint8_t, 400> utf8d =
| ^~~~~
0x30ec4d3 diagnostic_context::diagnostic_impl(rich_location*,
diagnostic_metadata const*, diagnostic_option_id, char const*, __va_list_tag
(*) [1], diagnostic_t)
???:0
0x3102033 internal_error(char const*, ...)
???:0
0x12cf8e3 store_init_value(tree_node*, tree_node*, vec<tree_node*, va_gc,
vl_embed>**, int)
???:0
0x10c5edc cp_finish_decl(tree_node*, tree_node*, bool, tree_node*, int,
cp_decomp*)
???:0
0x1218ffd instantiate_decl(tree_node*, bool, bool)
???:0
0x125224b instantiate_pending_templates(int)
???:0
0x10d9459 c_parse_final_cleanups()
???:0
0x134bae8 c_common_parse_file()
???:0
Please submit a full bug report, with preprocessed source.
Please include the complete backtrace with any bug report.
See <file:///usr/share/doc/gcc-15/README.Bugs> for instructions.
```
