https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98586
Bug ID: 98586 Summary: libgccjit crashes with segmentation fault on failed gcc_assert Product: gcc Version: 9.2.0 Status: UNCONFIRMED Severity: normal Priority: P3 Component: jit Assignee: dmalcolm at gcc dot gnu.org Reporter: keith.marshall at mailinator dot com Target Milestone: --- In response to a feature request by Eli Zaretskii, with my follow-up as detailed at https://osdn.net/projects/mingw/ticket/41070, I have been evaluating the feasibility of providing a libgccjit.dll implementation for mingw32. Since GCC-9.2.0 is the most recent version, for which I have a successful build of GCC itself, my initial efforts have been focussed on a libgccjit implementation for that version. With a series of patches, as attached to the OSDN ticket, I have successfully compiled the shared library, as libgccjit-0.dll; I am even able to successfully compile, and link, the tut01-hello-world.c example from your own online manual, at https://gcc.gnu.org/onlinedocs/jit/intro/tutorial01.html. Unfortunately however, when attempting to run this program, it crashes with a segmentation fault, and no useful diagnostic message. I have traced the origin of the crash to a failing assertion, at line 54 in gcc/jit/jit-tempdir.c. The failure of the assertion, as explained in the OSDN ticket, is due to it testing an invalid assumption — on MS-Windows, both '/' and '\\' are valid directory name separator characters, but the assertion requires '/', whereas the libiberty.a choose_tmpdir() function returns a path containing, and ending with, only '\\'. While I can easily, and will, correct the invalid assumption, on which the assertion fails, that the failed assertion terminates in a segmentation fault, rather than a graceful termination, with an appropriate diagnostic message, indicates that there is a deeper seated underlying defect. The segmentation fault actually occurs in function pp_format(), from gcc/pretty-print.c, when it attempts to dereference a NULL pointer, passed as the printer member of the global_dc structure. I guess that this structure has not been initialized; perhaps a call to diagnostic_initialize() has been omitted, but I have no idea where to insert it.