[PATCH 3/4] gdb: aarch64: Remove MTE address checking from memtag_matches_p

[Gustavo Romero <gustavo.romero@linaro.org>]

This commit removes aarch64_linux_tagged_address_p from
aarch64_linux_memtag_matches_p. aarch64_linux_tagged_address_p checks if
an address is tagged (MTE) or not.

The check is redundant because aarch64_linux_memtag_matches_p is always
called from the upper layers (i.e. from printcmd.c via gdbarch hook
gdbarch_memtag_matches_p) after either gdbarch_tagged_address_p (that
already points to aarch64_linux_tagged_address_p) has been called or
after should_validate_memtags (that calls gdbarch_tagged_address_p at
the end) has been called, so the address is already checked. Hence:

a) in print_command_1, gdbarch_memtag_matches_p is called only after
should_validate_memtags is called, which checks the address at its end;

b) in memory_tag_check_command, gdbarch_memtag_matches_p is called only
after gdbarch_tagged_address_p is called directly.

Also, because after this change the address checking only happens at the
upper layer it now allows the address checking to be specialized easily
per target, via a target hook.

Signed-off-by: Gustavo Romero <gustavo.romero@linaro.org>
---
 gdb/aarch64-linux-tdep.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/gdb/aarch64-linux-tdep.c b/gdb/aarch64-linux-tdep.c
index 8e6e63d4dcb..fc60e602748 100644
--- a/gdb/aarch64-linux-tdep.c
+++ b/gdb/aarch64-linux-tdep.c
@@ -2476,10 +2476,6 @@ aarch64_linux_memtag_matches_p (struct gdbarch *gdbarch,
 {
   gdb_assert (address != nullptr);
 
-  /* Make sure we are dealing with a tagged address to begin with.  */
-  if (!aarch64_linux_tagged_address_p (gdbarch, address))
-    return true;
-
   CORE_ADDR addr = value_as_address (address);
 
   /* Fetch the allocation tag for ADDRESS.  */
-- 
2.34.1