[Morello] Mask the LSB from cap mode addresses

This patch removes the LSB from capability mode addresses. This is a bit set
to indicate that a given function deals with capabilities.

gdb/ChangeLog:

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

	* aarch64-tdep.c (aarch64_addr_bits_remove): New function.
	(aarch64_gdbarch_init): Register hook.

diff --git a/gdb/aarch64-tdep.c b/gdb/aarch64-tdep.c
index 2e8feb033c247475e064c5acc768ea60d9d79a09..7c9d238fe2d7334d5521bc85ffb211041e0281a1 100644 (file)
--- a/gdb/aarch64-tdep.c
+++ b/gdb/aarch64-tdep.c
@@ -3609,6 +3609,15 @@ aarch64_integer_to_address (struct gdbarch *gdbarch,
   return aarch64_pointer_to_address (gdbarch, type, buf);
 }
 
+/* Remove useless bits from addresses in a running program.  This is
+   important for Morello due to the C64 mode having the LSB set.  */
+
+static CORE_ADDR
+aarch64_addr_bits_remove (struct gdbarch *gdbarch, CORE_ADDR val)
+{
+  return (val & ~1);
+}
+
 /* Initialize the current architecture based on INFO.  If possible,
    re-use an architecture from ARCHES, which is a list of
    architectures already created during this debugging session.
@@ -3927,6 +3936,9 @@ aarch64_gdbarch_init (struct gdbarch_info info, struct gdbarch_list *arches)
   /* Set address class hooks for capabilities.  */
   if (feature_capability)
     {
+      /* Address manipulation.  */
+      set_gdbarch_addr_bits_remove (gdbarch, aarch64_addr_bits_remove);
+
       set_gdbarch_address_class_type_flags
        (gdbarch, aarch64_address_class_type_flags);
       set_gdbarch_address_class_name_to_type_flags