aarch64: Add support for bfloat16 in gdb.

This patch adds support for bfloat16 in AArch64 gdb.
Also adds the field "bf" to vector registers h0-h31.
Also adds the vector "bf" to h field in vector registers v0-v31.

The following is how the vector register h and v looks like.

Before this patch:
(gdb) p $h0
$1 = {f = 0, u = 0, s = 0}
(gdb) p/x $h0
$2 = {f = 0x0, u = 0x0, s = 0x0}
(gdb) p $v0.h
$3 = {f = {0, 0, 0, 0, 0, 0, 0, 0}, u = {0, 0, 0, 0, 0, 0, 0, 0}, s = {0, 0, 0, 0, 0, 0, 0, 0}}
(gdb) p/x $v0.h
$4 = {f = {0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0}, u = {0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0},
      s = {0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0}}

After this patch:
(gdb) p $h0
$1 = {bf = 0, f = 0, u = 0, s = 0}
(gdb) p/x $h0
$2 = {bf = 0x0, f = 0x0, u = 0x0, s = 0x0}
(gdb) p $v0.h
$3 = {bf = {0, 0, 0, 0, 0, 0, 0, 0}, f = {0, 0, 0, 0, 0, 0, 0, 0}, u = {0, 0, 0, 0, 0, 0, 0, 0},
      s = {0, 0, 0, 0, 0, 0, 0, 0}}
(gdb) p/x $v0.h
$4 = {bf = {0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0}, f = {0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0},
      u = {0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0}, s = {0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0}}

gdb/ChangeLog:

2021-01-12  Srinath Parvathaneni  <srinath.parvathaneni@arm.com>

	* aarch64-tdep.c (aarch64_vnh_type): Add "bf" field in h registers.
	(aarch64_vnv_type): Add "bf" type in h field of v registers.
	* features/aarch64-fpu.c (create_feature_aarch64_fpu): Regenerated.
	* features/aarch64-fpu.xml: Add bfloat16 type.

gdb/testsuite/ChangeLog:

2021-01-12  Srinath Parvathaneni  <srinath.parvathaneni@arm.com>

	* gdb.arch/aarch64-fp.exp: Modify to test bfloat16 support.

6 files changed, 48 insertions, 0 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index d4a1b98aaca..27d5b96f141 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,10 @@
+2021-01-12  Srinath Parvathaneni  <srinath.parvathaneni@arm.com>
+
+	* aarch64-tdep.c (aarch64_vnh_type): Add "bf" field in h registers.
+	(aarch64_vnv_type): Add "bf" type in h field of v registers.
+	* features/aarch64-fpu.c (create_feature_aarch64_fpu): Regenerated.
+	* features/aarch64-fpu.xml: Add bfloat16 type.
+
 2021-01-12  Andrew Burgess  <andrew.burgess@embecosm.com>
 
 	* expprint.c (dump_subexp_body_standard): Handle OP_BOOL.
diff --git a/gdb/aarch64-tdep.c b/gdb/aarch64-tdep.c
index 5d1d979cd37..7099f180101 100644
--- a/gdb/aarch64-tdep.c
+++ b/gdb/aarch64-tdep.c
@@ -2040,6 +2040,9 @@ aarch64_vnh_type (struct gdbarch *gdbarch)
       t = arch_composite_type (gdbarch, "__gdb_builtin_type_vnh",
 			       TYPE_CODE_UNION);
 
+      elem = builtin_type (gdbarch)->builtin_bfloat16;
+      append_composite_type_field (t, "bf", elem);
+
       elem = builtin_type (gdbarch)->builtin_half;
       append_composite_type_field (t, "f", elem);
 
@@ -2121,6 +2124,8 @@ aarch64_vnv_type (struct gdbarch *gdbarch)
 
       sub = arch_composite_type (gdbarch, "__gdb_builtin_type_vnh",
 				 TYPE_CODE_UNION);
+      append_composite_type_field (sub, "bf",
+				   init_vector_type (bt->builtin_bfloat16, 8));
       append_composite_type_field (sub, "f",
 				   init_vector_type (bt->builtin_half, 8));
       append_composite_type_field (sub, "u",
diff --git a/gdb/features/aarch64-fpu.c b/gdb/features/aarch64-fpu.c
index 5b636a5f4d2..a80b7d4c1b8 100644
--- a/gdb/features/aarch64-fpu.c
+++ b/gdb/features/aarch64-fpu.c
@@ -37,6 +37,9 @@ create_feature_aarch64_fpu (struct target_desc *result, long regnum)
   element_type = tdesc_named_type (feature, "int16");
   tdesc_create_vector (feature, "v8i", element_type, 8);
 
+  element_type = tdesc_named_type (feature, "bfloat16");
+  tdesc_create_vector (feature, "v8bf16", element_type, 8);
+
   element_type = tdesc_named_type (feature, "uint8");
   tdesc_create_vector (feature, "v16u", element_type, 16);
 
@@ -68,6 +71,8 @@ create_feature_aarch64_fpu (struct target_desc *result, long regnum)
   tdesc_add_field (type_with_fields, "s", field_type);
 
   type_with_fields = tdesc_create_union (feature, "vnh");
+  field_type = tdesc_named_type (feature, "v8bf16");
+  tdesc_add_field (type_with_fields, "bf", field_type);
   field_type = tdesc_named_type (feature, "v8f");
   tdesc_add_field (type_with_fields, "f", field_type);
   field_type = tdesc_named_type (feature, "v8u");
diff --git a/gdb/features/aarch64-fpu.xml b/gdb/features/aarch64-fpu.xml
index 14b31373734..2235d072a09 100644
--- a/gdb/features/aarch64-fpu.xml
+++ b/gdb/features/aarch64-fpu.xml
@@ -17,6 +17,7 @@
   <vector id="v8f" type="ieee_half" count="8"/>
   <vector id="v8u" type="uint16" count="8"/>
   <vector id="v8i" type="int16" count="8"/>
+  <vector id="v8bf16" type="bfloat16" count="8"/>
   <vector id="v16u" type="uint8" count="16"/>
   <vector id="v16i" type="int8" count="16"/>
   <vector id="v1u" type="uint128" count="1"/>
@@ -32,6 +33,7 @@
     <field name="s" type="v4i"/>
   </union>
   <union id="vnh">
+    <field name="bf" type="v8bf16"/>
     <field name="f" type="v8f"/>
     <field name="u" type="v8u"/>
     <field name="s" type="v8i"/>
diff --git a/gdb/testsuite/ChangeLog b/gdb/testsuite/ChangeLog
index 7c24f66b914..eb42dedc18e 100644
--- a/gdb/testsuite/ChangeLog
+++ b/gdb/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2021-01-12  Srinath Parvathaneni  <srinath.parvathaneni@arm.com>
+
+	* gdb.arch/aarch64-fp.exp: Modify to test bfloat16 support.
+
 2021-01-12  Tom de Vries  <tdevries@suse.de>
 
 	* gdb.base/disasm-optim.exp: Require is_amd64_regs_target.
diff --git a/gdb/testsuite/gdb.arch/aarch64-fp.exp b/gdb/testsuite/gdb.arch/aarch64-fp.exp
index 8d06a3f5201..4fb8e343c49 100644
--- a/gdb/testsuite/gdb.arch/aarch64-fp.exp
+++ b/gdb/testsuite/gdb.arch/aarch64-fp.exp
@@ -75,3 +75,28 @@ gdb_test "p/x \$fpcr" \
     "fpcr.*0x\[0-9a-fA-F\].*" \
     "check register fpcr value"
 
+with_test_prefix "bfloat16" {
+    gdb_test "set \$h0.bf = 1.185e-38" \
+    ".*" \
+    "set h0.bf to 129"
+
+    gdb_test "p \$h0" \
+    "h0.*{bf = 1.185e-38, f = 7.689e-06, u = 129, s = 129}" \
+    "h0 fields are valid"
+
+    gdb_test "set \$v0.h.bf\[0\] = 0" \
+    "v0.* = 0" \
+    "set v0.h.bf\[0\] to 0"
+
+    gdb_test "p \$v0.h.s\[0\]" \
+    "v0.* = 0" \
+    "v0.h.s\[0\] is 0"
+
+    gdb_test "set \$v0.h.bf\[0\] = 1.185e-38" \
+    "v0.* = 1.185e-38" \
+    "set v0.h.bf\[0\] to 129"
+
+    gdb_test "p \$v0.h.s\[0\]" \
+    "v0.* = 129" \
+    "v0.h.s\[0\] is 129"
+}