[Morello] Add set/show ABI command for AArch64

Add a new command for developers to set and show the AArch64 ABI GDB is
using at the moment.

We define 2 ABI's: AAPCS64 and AAPCS64-cap.

Each of these ABI's should impact the architecture setup in different ways.

gdb/ChangeLog:

2020-10-20  Luis Machado  <luis.machado@arm.com>

	* aarch64-tdep.c (set_aarch64_cmdlist, show_aarch64_cmdlist,
	aarch64_abi_strings, aarch64_current_abi_global)
	(aarch64_current_abi_string): New static globals.
	(aarch64_update_current_architecture, aarch64_set_abi)
	(aarch64_show_abi): New functions.
	(aarch64_gdbarch_init): Handle ABI identification.
	(_initialize_aarch64_tdep): Add new ABI commands.
	* aarch64-tdep.h (aarch64_abi_kind): New enum.
	(struct gdbarch_tdep) <abi>: New field.

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index e477c46fac3bf0384f2135e8e5532fa710474b78..1a40953f3ac81581fd92d5116dd7cfb82aa88d0d 100644 (file)
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,15 @@
+2020-10-20  Luis Machado  <luis.machado@arm.com>
+
+       * aarch64-tdep.c (set_aarch64_cmdlist, show_aarch64_cmdlist,
+       aarch64_abi_strings, aarch64_current_abi_global)
+       (aarch64_current_abi_string): New static globals.
+       (aarch64_update_current_architecture, aarch64_set_abi)
+       (aarch64_show_abi): New functions.
+       (aarch64_gdbarch_init): Handle ABI identification.
+       (_initialize_aarch64_tdep): Add new ABI commands.
+       * aarch64-tdep.h (aarch64_abi_kind): New enum.
+       (struct gdbarch_tdep) <abi>: New field.
+
 2020-10-20  Luis Machado  <luis.machado@arm.com>
 
        * c-typeprint.c (c_type_print_varspec_prefix)

diff --git a/gdb/aarch64-tdep.c b/gdb/aarch64-tdep.c
index d9b55fdbdd03c8445a0e50379be997e7af4f7695..f882a0a465244ee681aecb0fe4545d46ef52736e 100644 (file)
--- a/gdb/aarch64-tdep.c
+++ b/gdb/aarch64-tdep.c
@@ -66,6 +66,79 @@
 /* All possible aarch64 target descriptors.  */
 struct target_desc *tdesc_aarch64_list[AARCH64_MAX_SVE_VQ + 1][2/*pauth*/][2 /* capability */];
 
+/* The list of available aarch64 set/show commands.  */
+static struct cmd_list_element *set_aarch64_cmdlist = NULL;
+static struct cmd_list_element *show_aarch64_cmdlist = NULL;
+
+/* The ABI to use.  Keep this in sync with aarch64_abi_kind.  */
+static const char *const aarch64_abi_strings[] =
+{
+  "auto",
+  "AAPCS64",
+  "AAPCS64-cap",
+  nullptr
+};
+
+/* Variables for the ABI user setting.  */
+static enum aarch64_abi_kind aarch64_current_abi_global = AARCH64_ABI_AUTO;
+static const char *aarch64_current_abi_string = "auto";
+
+static void
+aarch64_update_current_architecture (void)
+{
+  struct gdbarch_info info;
+
+  /* If the current architecture is not AArch64, we have nothing to do.  */
+  if (gdbarch_bfd_arch_info (target_gdbarch ())->arch != bfd_arch_aarch64)
+    return;
+
+  /* Update the architecture.  */
+  gdbarch_info_init (&info);
+
+  if (!gdbarch_update_p (info))
+    internal_error (__FILE__, __LINE__, _("could not update architecture"));
+}
+
+/* Sets the current ABI for AArch64.  */
+
+static void
+aarch64_set_abi (const char *args, int from_tty,
+                struct cmd_list_element *c)
+{
+  int abi;
+
+  for (abi = AARCH64_ABI_AUTO; abi != AARCH64_ABI_LAST; abi++)
+    if (strcmp (aarch64_current_abi_string, aarch64_abi_strings[abi]) == 0)
+      {
+       aarch64_current_abi_global = (enum aarch64_abi_kind) abi;
+       break;
+      }
+
+  if (abi == AARCH64_ABI_LAST)
+    internal_error (__FILE__, __LINE__, _("Invalid ABI accepted: %s."),
+                   aarch64_current_abi_string);
+
+  aarch64_update_current_architecture ();
+}
+
+/* Shows the current ABI for AArch64.  */
+
+static void
+aarch64_show_abi (struct ui_file *file, int from_tty,
+                 struct cmd_list_element *c, const char *value)
+{
+  struct gdbarch_tdep *tdep = gdbarch_tdep (target_gdbarch ());
+
+  if (aarch64_current_abi_global == AARCH64_ABI_AUTO
+      && gdbarch_bfd_arch_info (target_gdbarch ())->arch == bfd_arch_aarch64)
+    fprintf_filtered (file, _("\
+The current AArch64 ABI is \"auto\" (currently \"%s\").\n"),
+                     aarch64_abi_strings[tdep->abi]);
+  else
+    fprintf_filtered (file, _("The current AArch64 ABI is \"%s\".\n"),
+                     aarch64_current_abi_string);
+}
+
 /* The standard register names, and all the valid aliases for them.  */
 static const struct
 {
@@ -3433,6 +3506,8 @@ aarch64_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
   bool valid_p = true;
   int i, num_regs = 0, num_pseudo_regs = 0;
   int first_pauth_regnum = -1, pauth_ra_state_offset = -1;
+  aarch64_abi_kind abi = (aarch64_current_abi_global == AARCH64_ABI_AUTO)?
+    AARCH64_ABI_AAPCS64 : aarch64_current_abi_global;
 
   /* Use the vector length passed via the target info.  Here -1 is used for no
      SVE, and 0 is unset.  If unset then use the vector length from the existing
@@ -3573,6 +3648,7 @@ aarch64_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
   struct gdbarch_tdep *tdep = XCNEW (struct gdbarch_tdep);
   struct gdbarch *gdbarch = gdbarch_alloc (&info, tdep);
 
+  tdep->abi = abi;
   /* This should be low enough for everything.  */
   tdep->lowest_pc = 0x20;
   tdep->jb_pc = -1;            /* Longjump support not enabled by default.  */
@@ -3710,8 +3786,11 @@ aarch64_dump_tdep (struct gdbarch *gdbarch, struct ui_file *file)
   if (tdep == NULL)
     return;
 
-  fprintf_unfiltered (file, _("aarch64_dump_tdep: Lowest pc = 0x%s"),
-                     paddress (gdbarch, tdep->lowest_pc));
+  fprintf_unfiltered (file, _("%s: Lowest pc = 0x%s"),
+                     __func__, paddress (gdbarch, tdep->lowest_pc));
+
+  fprintf_unfiltered (file, _("%s: ABI is %s"),
+                     __func__, aarch64_abi_strings[tdep->abi]);
 }
 
 #if GDB_SELF_TEST
@@ -3752,6 +3831,23 @@ _initialize_aarch64_tdep ()
   gdbarch_register (bfd_arch_aarch64, aarch64_gdbarch_init,
                    aarch64_dump_tdep);
 
+  /* Add root prefix command for all set/show aarch64 commands.  */
+  add_basic_prefix_cmd ("aarch64", no_class,
+                       _("Various AArch64-specific commands."),
+                       &set_aarch64_cmdlist, "set aarch64 ", 0, &setlist);
+
+  add_show_prefix_cmd ("aarch64", no_class,
+                      _("Various AArch64-specific commands."),
+                      &show_aarch64_cmdlist, "show aarch64 ", 0, &showlist);
+
+  /* Add a command to allow the user to force the ABI.  */
+  add_setshow_enum_cmd ("abi", class_support, aarch64_abi_strings,
+                       &aarch64_current_abi_string,
+                       _("Set the ABI."),
+                       _("Show the ABI."),
+                       NULL, aarch64_set_abi, aarch64_show_abi,
+                       &set_aarch64_cmdlist, &show_aarch64_cmdlist);
+
   /* Debug this file's internals.  */
   add_setshow_boolean_cmd ("aarch64", class_maintenance, &aarch64_debug, _("\
 Set AArch64 debugging."), _("\

diff --git a/gdb/aarch64-tdep.h b/gdb/aarch64-tdep.h
index 3a2c30c47f360680b253fc6c4291eeced7643977..c7238207c0ec72a130bd571f376fe25fcc95dc37 100644 (file)
--- a/gdb/aarch64-tdep.h
+++ b/gdb/aarch64-tdep.h
@@ -66,9 +66,24 @@ struct regset;
    single-stepped instruction.  */
 #define AARCH64_DISPLACED_MODIFIED_INSNS 1
 
+/* AArch64 ABI used by the inferior.  */
+enum aarch64_abi_kind
+{
+  AARCH64_ABI_AUTO,
+  /* Procedure Call Standard for the Arm 64-bit Architecture.  */
+  AARCH64_ABI_AAPCS64,
+  /* The pure capability Procedure Call Standard for the Arm 64-bit
+     Architecture (AArch64).  */
+  AARCH64_ABI_AAPCS64_CAP,
+  AARCH64_ABI_LAST
+};
+
 /* Target-dependent structure in gdbarch.  */
 struct gdbarch_tdep
 {
+  /* The current ABI.  */
+  aarch64_abi_kind abi;
+
   /* Lowest address at which instructions will appear.  */
   CORE_ADDR lowest_pc;