https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104069
--- Comment #32 from Sergei Trofimovich <slyfox at gcc dot gnu.org> --- Created attachment 55068 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=55068&action=edit gzip.c.c > > You should be able to extract preprocessed file using > > https://gcc.gnu.org/bugs/#need: you will need to find exact `gcc` invocation > > that causes build failure, add `-save-temps` parameter to it, grab '*.i' > > file and attach it along with exact command you used to produce it. > > That gcc page does not say how to extract the command from the makefile that > triggers the error, so I've tried to reproduce this bug manually and after > like the 8th attempt when all the header files were finally found by the > compiler, the linker errored out with some undefined references, so no luck. > The good new is that this error is reproducible if the > cflags/ldflags/configure...etc switches set up like in c#29 gcc help can't cover specifics of external build systems. You have to have a bit of expertise to extract the actual command build system runs. As elfutils is an automake-maked '$ make V=1' will print you every gcc command the build system is running. It should be in a form you can copy and paste as is (modulo current directory and a few environment variables). I think I reproduced it on gcc-12.2.0 and elfutils-0.189. Attached as gzip.c.c. Trigger on gcc-12.2.0: $ gcc -std=gnu99 -Wall -Werror -Os -mtune=generic -c gzip.c.c In function 'bigger_buffer', inlined from '__libdw_gunzip' at gzip.c.c:7751:13: gzip.c.c:7609:13: error: pointer may be used after 'realloc' [-Werror=use-after-free] 7609 | b = realloc (state->buffer, more -= 1024); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ gzip.c.c:7605:15: note: call to 'realloc' here 7605 | char *b = realloc (state->buffer, more); | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ cc1: all warnings being treated as errors gcc-master does not seem to reproduce the failure. I did not test gcc-13.
