[PATCH 2/3] [AArch64] Handle HFA and HVA together

[Yao Qi <qiyaoltc@gmail.com>]

AArch64 AAPCS defined HFA (homogeneous floating-point aggregate)
and HVF (homogeneous short vector aggregate), bug GDB only handles the
former.  In the AAPCS doc, both types are treated exactly the same
in terms of alignment and passing locations (on registers or stack).
This patch is to extend is_hfa to handle both HFA and HVA.

gdb:

2015-11-20  Yao Qi  <yao.qi@linaro.org>

	* aarch64-tdep.c (is_hfa): Rename to ...
	(is_hfa_or_hva): ... this.  Handle vector type.  All callers
	updated.
	(aarch64_extract_return_value): Update debugging message.
	(aarch64_store_return_value): Likewise.
	(aarch64_return_in_memory): Update comments.
---
 gdb/aarch64-tdep.c | 37 ++++++++++++++++++++-----------------
 1 file changed, 20 insertions(+), 17 deletions(-)

diff --git a/gdb/aarch64-tdep.c b/gdb/aarch64-tdep.c
index 175ed08..cdc1b93 100644
--- a/gdb/aarch64-tdep.c
+++ b/gdb/aarch64-tdep.c
@@ -921,11 +921,12 @@ aarch64_type_align (struct type *t)
     }
 }
 
-/* Return 1 if *TY is a homogeneous floating-point aggregate as
-   defined in the AAPCS64 ABI document; otherwise return 0.  */
+/* Return 1 if *TY is a homogeneous floating-point aggregate or
+   homogeneous short-vector aggregate as defined in the AAPCS64 ABI
+   document; otherwise return 0.  */
 
 static int
-is_hfa (struct type *ty)
+is_hfa_or_hva (struct type *ty)
 {
   switch (TYPE_CODE (ty))
     {
@@ -936,7 +937,10 @@ is_hfa (struct type *ty)
 	if (TYPE_VECTOR (ty))
 	  return 0;
 
-	if (TYPE_CODE (target_ty) == TYPE_CODE_FLT && TYPE_LENGTH (ty) <= 4)
+	if (TYPE_LENGTH (ty) <= 4 /* HFA or HVA has at most 4 members.  */
+	    && (TYPE_CODE (target_ty) == TYPE_CODE_FLT /* HFA */
+		|| (TYPE_CODE (target_ty) == TYPE_CODE_ARRAY /* HVA */
+		    && TYPE_VECTOR (target_ty))))
 	  return 1;
 	break;
       }
@@ -944,12 +948,15 @@ is_hfa (struct type *ty)
     case TYPE_CODE_UNION:
     case TYPE_CODE_STRUCT:
       {
+	/* HFA or HVA has at most four members.  */
 	if (TYPE_NFIELDS (ty) > 0 && TYPE_NFIELDS (ty) <= 4)
 	  {
 	    struct type *member0_type;
 
 	    member0_type = check_typedef (TYPE_FIELD_TYPE (ty, 0));
-	    if (TYPE_CODE (member0_type) == TYPE_CODE_FLT)
+	    if (TYPE_CODE (member0_type) == TYPE_CODE_FLT
+		|| (TYPE_CODE (member0_type) == TYPE_CODE_ARRAY
+		    && TYPE_VECTOR (member0_type)))
 	      {
 		int i;
 
@@ -1304,7 +1311,7 @@ aarch64_push_dummy_call (struct gdbarch *gdbarch, struct value *function,
 	case TYPE_CODE_STRUCT:
 	case TYPE_CODE_ARRAY:
 	case TYPE_CODE_UNION:
-	  if (is_hfa (arg_type))
+	  if (is_hfa_or_hva (arg_type))
 	    {
 	      int elements = TYPE_NFIELDS (arg_type);
 
@@ -1640,7 +1647,7 @@ aarch64_extract_return_value (struct type *type, struct regcache *regs,
       memcpy (valbuf, buf, len);
       valbuf += len;
     }
-  else if (is_hfa (type))
+  else if (is_hfa_or_hva (type))
     {
       int elements = TYPE_NFIELDS (type);
       struct type *member_type = check_typedef (TYPE_FIELD_TYPE (type, 0));
@@ -1654,7 +1661,7 @@ aarch64_extract_return_value (struct type *type, struct regcache *regs,
 
 	  if (aarch64_debug)
 	    {
-	      debug_printf ("read HFA return value element %d from %s\n",
+	      debug_printf ("read HFA or HVA return value element %d from %s\n",
 			    i + 1,
 			    gdbarch_register_name (gdbarch, regno));
 	    }
@@ -1705,14 +1712,10 @@ aarch64_return_in_memory (struct gdbarch *gdbarch, struct type *type)
 
   type = check_typedef (type);
 
-  /* In the AArch64 ABI, "integer" like aggregate types are returned
-     in registers.  For an aggregate type to be integer like, its size
-     must be less than or equal to 4 * X_REGISTER_SIZE.  */
-
-  if (is_hfa (type))
+  if (is_hfa_or_hva (type))
     {
-      /* PCS B.5 If the argument is a Named HFA, then the argument is
-         used unmodified.  */
+      /* v0-v7 are used to return values and one register is allocated
+	 for one member.  However, HFA or HVA has at most four members.  */
       return 0;
     }
 
@@ -1778,7 +1781,7 @@ aarch64_store_return_value (struct type *type, struct regcache *regs,
 	    }
 	}
     }
-  else if (is_hfa (type))
+  else if (is_hfa_or_hva (type))
     {
       int elements = TYPE_NFIELDS (type);
       struct type *member_type = check_typedef (TYPE_FIELD_TYPE (type, 0));
@@ -1792,7 +1795,7 @@ aarch64_store_return_value (struct type *type, struct regcache *regs,
 
 	  if (aarch64_debug)
 	    {
-	      debug_printf ("write HFA return value element %d to %s\n",
+	      debug_printf ("write HFA or HVA return value element %d to %s\n",
 			    i + 1,
 			    gdbarch_register_name (gdbarch, regno));
 	    }
-- 
1.9.1