All platforms on FreeBSD use a shared system call table, so use a
single XML file to describe the system calls available on each FreeBSD
platform.
Recent versions of FreeBSD include the identifier of the current
system call when reporting a system call entry or exit event in the
ptrace_lwpinfo structure obtained via PT_LWPINFO in fbsd_wait. As
such, FreeBSD native targets do not use the gdbarch method to fetch
the system call code. In addition, FreeBSD register sets fetched via
ptrace do not include an equivalent of 'orig_rax' (on amd64 for
example), so the system call code cannot be extracted from the
available registers during a system call exit. However, GDB assumes
that system call catch points are not supported if the gdbarch method
is not present. As a workaround, FreeBSD ABIs install a dummy gdbarch
method that throws an internal_error if it is ever invoked.
gdb/ChangeLog:
* configure.ac: Check for support for system call LWP fields on
FreeBSD.
* config.in, configure: Rebuild.
* data-directory/Makefile.in (SYSCALLS_FILES): Add freebsd.xml.
* fbsd-nat.c (fbsd_wait) [HAVE_STRUCT_PTRACE_LWPINFO_PL_SYSCALL_CODE]:
Report system call events.
[HAVE_STRUCT_PTRACE_LWPINFO_PL_SYSCALL_CODE]
(fbsd_set_syscall_catchpoint): New function.
(fbsd_nat_add_target) [HAVE_STRUCT_PTRACE_LWPINFO_PL_SYSCALL_CODE]:
Set "to_set_syscall_catchpoint" to "fbsd_set_syscall_catchpoint".
* fbsd-tdep.c: Include xml-syscall.h
(fbsd_get_syscall_number): New function.
(fbsd_init_abi): Set XML system call file name.
Add "get_syscall_number" gdbarch method.
* syscalls/freebsd.xml: New file.
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