[PATCH v2 07/11] s390: Hook s390 into OSABI mechanism

[Philipp Rudo <prudo at linux dot vnet dot ibm dot com>]

Well do what the title says and distinguish between 31- and 64-bit systems.

There is one pitfall to take care of.  Appending the dwarf2 unwinder must
be moved _before_ the OSABI is initialized.  Otherwise a default unwinder
will take control before the dwarf unwinder even gets a chance.

gdb/ChangeLog:

	* s390-linux-tdep.c (osabi.h): New include
	(s390_linux_init_osabi_31, s390_linux_init_osabi_64)
	(s390_linux_init_osabi_any): New functions.
	(s390_gdbarch_init): Adjust.
---
 gdb/s390-linux-tdep.c | 155 +++++++++++++++++++++++++++++---------------------
 1 file changed, 91 insertions(+), 64 deletions(-)

diff --git a/gdb/s390-linux-tdep.c b/gdb/s390-linux-tdep.c
index f6a39868be..f8559eec49 100644
--- a/gdb/s390-linux-tdep.c
+++ b/gdb/s390-linux-tdep.c
@@ -30,6 +30,7 @@
 #include "gdbcore.h"
 #include "gdbcmd.h"
 #include "objfiles.h"
+#include "osabi.h"
 #include "regcache.h"
 #include "trad-frame.h"
 #include "frame-base.h"
@@ -8024,32 +8025,12 @@ s390_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
   struct tdesc_arch_data *tdesc_data = tdesc_data_alloc ();
   info.tdesc_data = tdesc_data;
 
-  /* Default ABI and register size.  */
-  switch (info.bfd_arch_info->mach)
-    {
-    case bfd_mach_s390_31:
-      tdep->abi = ABI_LINUX_S390;
-      break;
-
-    case bfd_mach_s390_64:
-      tdep->abi = ABI_LINUX_ZSERIES;
-      break;
-
-    default:
-      xfree (tdep);
-      gdbarch_free (gdbarch);
-      return NULL;
-    }
+  /* The DWARF unwinders must be appended before the ABI is initialized.
+     Otherwise it is possible that a ABI default unwinder gets called before
+     the DWARF unwinder even gets the chance.  */
+  dwarf2_append_unwinders (gdbarch);
 
-  /* Use default target description if none provided by the target.  */
-  if (!tdesc_has_registers (tdesc))
-    {
-      if (tdep->abi == ABI_LINUX_S390)
-	tdesc = tdesc_s390_linux32;
-      else
-	tdesc = tdesc_s390x_linux64;
-    }
-  tdep->tdesc = tdesc;
+  gdbarch_init_osabi (info, gdbarch);
 
   /* Check any target description for validity.  */
   gdb_assert (tdesc_has_registers (tdep->tdesc));
@@ -8100,12 +8081,7 @@ s390_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
   set_gdbarch_stab_reg_to_regnum (gdbarch, s390_dwarf_reg_to_regnum);
   set_gdbarch_dwarf2_reg_to_regnum (gdbarch, s390_dwarf_reg_to_regnum);
   set_gdbarch_value_from_register (gdbarch, s390_value_from_register);
-  set_gdbarch_core_read_description (gdbarch, s390_core_read_description);
-  set_gdbarch_iterate_over_regset_sections (gdbarch,
-					    s390_iterate_over_regset_sections);
   set_gdbarch_cannot_store_register (gdbarch, s390_cannot_store_register);
-  set_gdbarch_write_pc (gdbarch, s390_write_pc);
-  set_gdbarch_guess_tracepoint_registers (gdbarch, s390_guess_tracepoint_registers);
   set_gdbarch_pseudo_register_read (gdbarch, s390_pseudo_register_read);
   set_gdbarch_pseudo_register_write (gdbarch, s390_pseudo_register_write);
   set_tdesc_pseudo_register_name (gdbarch, s390_pseudo_register_name);
@@ -8144,18 +8120,10 @@ s390_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
   set_gdbarch_frame_align (gdbarch, s390_frame_align);
   set_gdbarch_return_value (gdbarch, s390_return_value);
 
-  /* Syscall handling.  */
-  set_gdbarch_get_syscall_number (gdbarch, s390_linux_get_syscall_number);
-
   /* Frame handling.  */
   dwarf2_frame_set_init_reg (gdbarch, s390_dwarf2_frame_init_reg);
   dwarf2_frame_set_adjust_regnum (gdbarch, s390_adjust_frame_regnum);
-  dwarf2_append_unwinders (gdbarch);
   frame_base_append_sniffer (gdbarch, dwarf2_frame_base_sniffer);
-  frame_unwind_append_unwinder (gdbarch, &s390_stub_frame_unwind);
-  frame_unwind_append_unwinder (gdbarch, &s390_sigtramp_frame_unwind);
-  frame_unwind_append_unwinder (gdbarch, &s390_frame_unwind);
-  frame_base_set_default (gdbarch, &s390_frame_base);
   set_gdbarch_unwind_pc (gdbarch, s390_unwind_pc);
   set_gdbarch_unwind_sp (gdbarch, s390_unwind_sp);
 
@@ -8166,65 +8134,118 @@ s390_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
   set_gdbarch_displaced_step_location (gdbarch, linux_displaced_step_location);
   set_gdbarch_max_insn_length (gdbarch, S390_MAX_INSTR_SIZE);
 
-  /* Note that GNU/Linux is the only OS supported on this
-     platform.  */
-  linux_init_abi (info, gdbarch);
-
   switch (tdep->abi)
     {
     case ABI_LINUX_S390:
       set_gdbarch_addr_bits_remove (gdbarch, s390_addr_bits_remove);
-      set_solib_svr4_fetch_link_map_offsets
-	(gdbarch, svr4_ilp32_fetch_link_map_offsets);
-
-      set_xml_syscall_file_name (gdbarch, XML_SYSCALL_FILENAME_S390);
       break;
 
     case ABI_LINUX_ZSERIES:
       set_gdbarch_long_bit (gdbarch, 64);
       set_gdbarch_long_long_bit (gdbarch, 64);
       set_gdbarch_ptr_bit (gdbarch, 64);
-      set_solib_svr4_fetch_link_map_offsets
-	(gdbarch, svr4_lp64_fetch_link_map_offsets);
       set_gdbarch_address_class_type_flags (gdbarch,
 					    s390_address_class_type_flags);
       set_gdbarch_address_class_type_flags_to_name (gdbarch,
 						    s390_address_class_type_flags_to_name);
       set_gdbarch_address_class_name_to_type_flags (gdbarch,
 						    s390_address_class_name_to_type_flags);
-      set_xml_syscall_file_name (gdbarch, XML_SYSCALL_FILENAME_S390X);
       break;
     }
 
-  set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target);
-
-  /* Enable TLS support.  */
-  set_gdbarch_fetch_tls_load_module_address (gdbarch,
-					     svr4_fetch_objfile_link_map);
-
   /* SystemTap functions.  */
   set_gdbarch_stap_register_prefixes (gdbarch, stap_register_prefixes);
   set_gdbarch_stap_register_indirection_prefixes (gdbarch,
 					  stap_register_indirection_prefixes);
   set_gdbarch_stap_register_indirection_suffixes (gdbarch,
 					  stap_register_indirection_suffixes);
-  set_gdbarch_stap_is_single_operand (gdbarch, s390_stap_is_single_operand);
-  set_gdbarch_gcc_target_options (gdbarch, s390_gcc_target_options);
-  set_gdbarch_gnu_triplet_regexp (gdbarch, s390_gnu_triplet_regexp);
 
-  /* Support reverse debugging.  */
+  set_gdbarch_disassembler_options (gdbarch, &s390_disassembler_options);
+  set_gdbarch_valid_disassembler_options (gdbarch,
+					  disassembler_options_s390 ());
+
+  return gdbarch;
+}
+
+/* Initialize OSABI common for GNU/Linux on 31- and 64-bit systems.  */
+
+static void
+s390_linux_init_abi_any (struct gdbarch_info info, struct gdbarch *gdbarch)
+{
+  linux_init_abi (info, gdbarch);
 
+  /* Register handling.  */
+  set_gdbarch_core_read_description (gdbarch, s390_core_read_description);
+  set_gdbarch_iterate_over_regset_sections (gdbarch,
+					    s390_iterate_over_regset_sections);
+  set_gdbarch_guess_tracepoint_registers (gdbarch,
+					  s390_guess_tracepoint_registers);
+  set_gdbarch_write_pc (gdbarch, s390_write_pc);
+
+  /* Syscall handling.  */
+  set_gdbarch_get_syscall_number (gdbarch, s390_linux_get_syscall_number);
+
+  /* Frame handling.  */
+  frame_unwind_append_unwinder (gdbarch, &s390_stub_frame_unwind);
+  frame_unwind_append_unwinder (gdbarch, &s390_sigtramp_frame_unwind);
+  frame_unwind_append_unwinder (gdbarch, &s390_frame_unwind);
+  frame_base_set_default (gdbarch, &s390_frame_base);
+  set_gdbarch_skip_trampoline_code (gdbarch, find_solib_trampoline_target);
+
+  /* Enable TLS support.  */
+  set_gdbarch_fetch_tls_load_module_address (gdbarch,
+					     svr4_fetch_objfile_link_map);
+
+  /* Support reverse debugging.  */
   set_gdbarch_process_record (gdbarch, s390_process_record);
   set_gdbarch_process_record_signal (gdbarch, s390_linux_record_signal);
-
   s390_init_linux_record_tdep (&s390_linux_record_tdep, ABI_LINUX_S390);
   s390_init_linux_record_tdep (&s390x_linux_record_tdep, ABI_LINUX_ZSERIES);
 
-  set_gdbarch_disassembler_options (gdbarch, &s390_disassembler_options);
-  set_gdbarch_valid_disassembler_options (gdbarch,
-					  disassembler_options_s390 ());
+  /* Miscellaneous.  */
+  set_gdbarch_stap_is_single_operand (gdbarch, s390_stap_is_single_operand);
+  set_gdbarch_gcc_target_options (gdbarch, s390_gcc_target_options);
+  set_gdbarch_gnu_triplet_regexp (gdbarch, s390_gnu_triplet_regexp);
+}
 
-  return gdbarch;
+/* Initialize OSABI for GNU/Linux on 31-bit systems.  */
+
+static void
+s390_linux_init_abi_31 (struct gdbarch_info info, struct gdbarch *gdbarch)
+{
+  const struct target_desc *tdesc = info.target_desc;
+  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+
+  tdep->abi = ABI_LINUX_S390;
+  if (!tdesc_has_registers (tdesc))
+    tdesc = tdesc_s390_linux32;
+  tdep->tdesc = tdesc;
+
+  s390_linux_init_abi_any (info, gdbarch);
+
+  set_solib_svr4_fetch_link_map_offsets (gdbarch,
+					 svr4_ilp32_fetch_link_map_offsets);
+  set_xml_syscall_file_name (gdbarch, XML_SYSCALL_FILENAME_S390);
+}
+
+/* Initialize OSABI for GNU/Linux on 64-bit systems.  */
+
+static void
+s390_linux_init_abi_64 (struct gdbarch_info info, struct gdbarch *gdbarch)
+{
+  const struct target_desc *tdesc = info.target_desc;
+  struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+
+  tdep->abi = ABI_LINUX_ZSERIES;
+  if (!tdesc_has_registers (tdesc))
+    tdesc = tdesc_s390x_linux64;
+  tdep->tdesc = tdesc;
+
+  s390_linux_init_abi_any (info, gdbarch);
+
+  set_solib_svr4_fetch_link_map_offsets (gdbarch,
+					 svr4_lp64_fetch_link_map_offsets);
+  set_xml_syscall_file_name (gdbarch, XML_SYSCALL_FILENAME_S390X);
 }
 
 void
@@ -8233,6 +8254,12 @@ _initialize_s390_tdep (void)
   /* Hook us into the gdbarch mechanism.  */
   register_gdbarch_init (bfd_arch_s390, s390_gdbarch_init);
 
+  /* Hook us into the OSABI mechanism.  */
+  gdbarch_register_osabi (bfd_arch_s390, bfd_mach_s390_31, GDB_OSABI_LINUX,
+			  s390_linux_init_abi_31);
+  gdbarch_register_osabi (bfd_arch_s390, bfd_mach_s390_64, GDB_OSABI_LINUX,
+			  s390_linux_init_abi_64);
+
   /* Initialize the GNU/Linux target descriptions.  */
   initialize_tdesc_s390_linux32 ();
   initialize_tdesc_s390_linux32v1 ();
-- 
2.13.5