gdb: Move DJGPP/go32 bits to their own tdep file

I posit that this makes them easier to find.

The other day while working on the wchar_t patch, I had a bit of
trouble finding the DJGPP/go32 tdep bits.  My initial reaction was
looking for a go32-specific tdep file, but there's none.

Confirmed that a --host=i586-pc-msdosdjgpp GDB still builds
successfully and includes the  i386-go32-tdep.o object.

Confirmed that an --enable-targets=all build of GDB on x86-64
GNU/Linux includes the DJGPP/go32 bits too.

gdb/ChangeLog:
2017-04-12  Pedro Alves  <palves@redhat.com>

	* Makefile.in (ALL_TARGET_OBS): Add i386-go32-tdep.o.
	* configure.tgt: Handle i[34567]86-*-go32* and
	i[34567]86-*-msdosdjgpp*.
	* i386-tdep.c (i386_svr4_reg_to_regnum):
	Make extern.
	(i386_go32_init_abi, i386_coff_osabi_sniffer): Moved to
	i386-go32-tdep.c.
	(_initialize_i386_tdep): DJGPP bits moved to i386-go32-tdep.c.
	* i386-go32-tdep.c: New file.
	* i386-tdep.h (tdesc_i386_mmx, i386_svr4_reg_to_regnum): New
	declarations.

1 files changed, 1 insertions, 43 deletions

diff --git a/gdb/i386-tdep.c b/gdb/i386-tdep.c
index 2edf5cf..fe68486 100644
--- a/gdb/i386-tdep.c
+++ b/gdb/i386-tdep.c
@@ -573,7 +573,7 @@ i386_svr4_dwarf_reg_to_regnum (struct gdbarch *gdbarch, int reg)
 /* Wrapper on i386_svr4_dwarf_reg_to_regnum to return
    num_regs + num_pseudo_regs for other debug formats.  */
 
-static int
+int
 i386_svr4_reg_to_regnum (struct gdbarch *gdbarch, int reg)
 {
   int regnum = i386_svr4_dwarf_reg_to_regnum (gdbarch, reg);
@@ -4487,34 +4487,6 @@ i386_svr4_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
   tdep->jb_pc_offset = 20;
 }
 
-/* DJGPP.  */
-
-static void
-i386_go32_init_abi (struct gdbarch_info info, struct gdbarch *gdbarch)
-{
-  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
-
-  /* DJGPP doesn't have any special frames for signal handlers.  */
-  tdep->sigtramp_p = NULL;
-
-  tdep->jb_pc_offset = 36;
-
-  /* DJGPP does not support the SSE registers.  */
-  if (! tdesc_has_registers (info.target_desc))
-    tdep->tdesc = tdesc_i386_mmx;
-
-  /* Native compiler is GCC, which uses the SVR4 register numbering
-     even in COFF and STABS.  See the comment in i386_gdbarch_init,
-     before the calls to set_gdbarch_stab_reg_to_regnum and
-     set_gdbarch_sdb_reg_to_regnum.  */
-  set_gdbarch_stab_reg_to_regnum (gdbarch, i386_svr4_reg_to_regnum);
-  set_gdbarch_sdb_reg_to_regnum (gdbarch, i386_svr4_reg_to_regnum);
-
-  set_gdbarch_has_dos_based_file_system (gdbarch, 1);
-
-  set_gdbarch_wchar_bit (gdbarch, 16);
-  set_gdbarch_wchar_signed (gdbarch, 0);
-}
 
 
 /* i386 register groups.  In addition to the normal groups, add "mmx"
@@ -8739,15 +8711,6 @@ i386_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
   return gdbarch;
 }
 
-static enum gdb_osabi
-i386_coff_osabi_sniffer (bfd *abfd)
-{
-  if (strcmp (bfd_get_target (abfd), "coff-go32-exe") == 0
-      || strcmp (bfd_get_target (abfd), "coff-go32") == 0)
-    return GDB_OSABI_GO32;
-
-  return GDB_OSABI_UNKNOWN;
-}
 
 
 /* Return the target description for a specified XSAVE feature mask.  */
@@ -9085,13 +9048,8 @@ Show Intel Memory Protection Extensions specific variables."),
  in the bound table.",
 	   &mpx_set_cmdlist);
 
-  gdbarch_register_osabi_sniffer (bfd_arch_i386, bfd_target_coff_flavour,
-				  i386_coff_osabi_sniffer);
-
   gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_SVR4,
 			  i386_svr4_init_abi);
-  gdbarch_register_osabi (bfd_arch_i386, 0, GDB_OSABI_GO32,
-			  i386_go32_init_abi);
 
   /* Initialize the i386-specific register groups.  */
   i386_init_reggroups ();