https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116805
Bug ID: 116805
Summary: -fno-module-lazy breaks thread module when compiled
after format module
Product: gcc
Version: 15.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c++
Assignee: unassigned at gcc dot gnu.org
Reporter: gcc at richy dot net
Target Milestone: ---
Created attachment 59171
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=59171&action=edit
Collection of *.ii files
richard@microserver:~/scratch/broken> gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/home/richard/gcc/lib/gcc/x86_64-pc-linux-gnu/15.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../configure --host=x86_64-pc-linux-gnu
--prefix=/home/richard/gcc --enable-threads --enable-language=c,c++
--disable-multilib
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 15.0.0 20240917 (experimental) (GCC)
Issued commands below, *.ii files attached.
g++ -std=c++2b -fmodules-ts -fconcepts -fno-module-lazy -Wall -O3 -g -fPIC
-save-temps -x c++-system-header format
g++ -std=c++2b -fmodules-ts -fconcepts -fno-module-lazy -Wall -O3 -g -fPIC
-save-temps -x c++-system-header thread
g++ -std=c++2b -fmodules-ts -fconcepts -fno-module-lazy -Wall -O3 -g -fPIC
-save-temps -c -o ex2.o -x c++ ex2.ixx
In module imported at ex2.ixx:3:1:
/home/richard/gcc/include/c++/15.0.0/thread: error: failed to read compiled
module cluster 1884: Bad file data
/home/richard/gcc/include/c++/15.0.0/thread: note: compiled module file is
‘gcm.cache/./home/richard/gcc/include/c++/15.0.0/thread.gcm’
/home/richard/gcc/include/c++/15.0.0/thread: error: failed to read compiled
module: Bad file data
/home/richard/gcc/include/c++/15.0.0/thread: fatal error: returning to the gate
for a mechanical issue
compilation terminated.
make: *** [Makefile:80: ex2.o] Error 1
Source code:
export module sorttools.sorts:foobar;
import <thread>;
export namespace sorttools::sorts::foobar {
class Pieces {
public:
std::jthread hello{};
};
}
On 15.0.0 removing the -fno-module-lazy flag will allow this to compile, as
does swapping the order of format/thread.
