gdb/alpha: Add target description support

This commit adds target description support for Alpha.

The target description obviates the alpha_register_type and
alpha_register_name functions in alpha-tdep.c. Removal of
alpha_register_reggroup_p was considered but ultimately abandoned,
because the "info regs" command would no longer omit the zero, fpcr, and
unique registers from its output (they are neither vector nor float
types).

Register types in the target description annex match the types that the
alpha_register_type function returned.

The locally defined register_names array was moved out of
alpha_register_name and renamed to alpha_register_names as a static
global; calls to alpha_register_name have been replaced with direct
access of the array.

The patch follows the code pattern outlined in the following GDB
Internals Wiki entry:

https://sourceware.org/gdb/wiki/Internals%20Adding-Target-Described-Register-Support

Reviewed-By: Eli Zaretskii <eliz@gnu.org>
Approved-By: Simon Marchi <simon.marchi@efficios.com>
Change-Id: If4b25a891228388519074a31a682e33358c71063

4 files changed, 184 insertions, 0 deletions

diff --git a/gdb/features/Makefile b/gdb/features/Makefile
index 7a8c799..750508a 100644
--- a/gdb/features/Makefile
+++ b/gdb/features/Makefile
@@ -100,6 +100,7 @@ OUTPUTS = $(patsubst %,$(outdir)/%.dat,$(WHICH))
 # --enable-targets=all GDB.  You can override this by passing XMLTOC
 # to make on the command line.
 XMLTOC = \
+	alpha.xml \
 	microblaze-with-stack-protect.xml \
 	microblaze.xml \
 	mips-dsp-linux.xml \
diff --git a/gdb/features/alpha-core.xml b/gdb/features/alpha-core.xml
new file mode 100644
index 0000000..9b4d71c
--- /dev/null
+++ b/gdb/features/alpha-core.xml
@@ -0,0 +1,88 @@
+<?xml version="1.0"?>
+<!-- Copyright (C) 2025 Free Software Foundation, Inc.
+
+     Copying and distribution of this file, with or without modification,
+     are permitted in any medium without royalty provided the copyright
+     notice and this notice are preserved.  -->
+
+<!DOCTYPE feature SYSTEM "gdb-target.dtd">
+<feature name="org.gnu.gdb.alpha.core">
+  <!-- Integer Registers -->
+  <reg name="v0"   bitsize="64" type="int64"/>
+  <reg name="t0"   bitsize="64" type="int64"/>
+  <reg name="t1"   bitsize="64" type="int64"/>
+  <reg name="t2"   bitsize="64" type="int64"/>
+  <reg name="t3"   bitsize="64" type="int64"/>
+  <reg name="t4"   bitsize="64" type="int64"/>
+  <reg name="t5"   bitsize="64" type="int64"/>
+  <reg name="t6"   bitsize="64" type="int64"/>
+  <reg name="t7"   bitsize="64" type="int64"/>
+  <reg name="s0"   bitsize="64" type="int64"/>
+  <reg name="s1"   bitsize="64" type="int64"/>
+  <reg name="s2"   bitsize="64" type="int64"/>
+  <reg name="s3"   bitsize="64" type="int64"/>
+  <reg name="s4"   bitsize="64" type="int64"/>
+  <reg name="s5"   bitsize="64" type="int64"/>
+  <reg name="fp"   bitsize="64" type="int64"/>
+  <reg name="a0"   bitsize="64" type="int64"/>
+  <reg name="a1"   bitsize="64" type="int64"/>
+  <reg name="a2"   bitsize="64" type="int64"/>
+  <reg name="a3"   bitsize="64" type="int64"/>
+  <reg name="a4"   bitsize="64" type="int64"/>
+  <reg name="a5"   bitsize="64" type="int64"/>
+  <reg name="t8"   bitsize="64" type="int64"/>
+  <reg name="t9"   bitsize="64" type="int64"/>
+  <reg name="t10"  bitsize="64" type="int64"/>
+  <reg name="t11"  bitsize="64" type="int64"/>
+  <reg name="ra"   bitsize="64" type="int64"/>
+  <reg name="t12"  bitsize="64" type="int64"/>
+  <reg name="at"   bitsize="64" type="int64"/>
+  <reg name="gp"   bitsize="64" type="data_ptr"/>
+  <reg name="sp"   bitsize="64" type="data_ptr"/>
+  <reg name="zero" bitsize="64" type="int64" save-restore="no"/>
+
+  <!-- Floating-Point Registers -->
+  <reg name="f0"  bitsize="64" type="float" group="float"/>
+  <reg name="f1"  bitsize="64" type="float" group="float"/>
+  <reg name="f2"  bitsize="64" type="float" group="float"/>
+  <reg name="f3"  bitsize="64" type="float" group="float"/>
+  <reg name="f4"  bitsize="64" type="float" group="float"/>
+  <reg name="f5"  bitsize="64" type="float" group="float"/>
+  <reg name="f6"  bitsize="64" type="float" group="float"/>
+  <reg name="f7"  bitsize="64" type="float" group="float"/>
+  <reg name="f8"  bitsize="64" type="float" group="float"/>
+  <reg name="f9"  bitsize="64" type="float" group="float"/>
+  <reg name="f10" bitsize="64" type="float" group="float"/>
+  <reg name="f11" bitsize="64" type="float" group="float"/>
+  <reg name="f12" bitsize="64" type="float" group="float"/>
+  <reg name="f13" bitsize="64" type="float" group="float"/>
+  <reg name="f14" bitsize="64" type="float" group="float"/>
+  <reg name="f15" bitsize="64" type="float" group="float"/>
+  <reg name="f16" bitsize="64" type="float" group="float"/>
+  <reg name="f17" bitsize="64" type="float" group="float"/>
+  <reg name="f18" bitsize="64" type="float" group="float"/>
+  <reg name="f19" bitsize="64" type="float" group="float"/>
+  <reg name="f20" bitsize="64" type="float" group="float"/>
+  <reg name="f21" bitsize="64" type="float" group="float"/>
+  <reg name="f22" bitsize="64" type="float" group="float"/>
+  <reg name="f23" bitsize="64" type="float" group="float"/>
+  <reg name="f24" bitsize="64" type="float" group="float"/>
+  <reg name="f25" bitsize="64" type="float" group="float"/>
+  <reg name="f26" bitsize="64" type="float" group="float"/>
+  <reg name="f27" bitsize="64" type="float" group="float"/>
+  <reg name="f28" bitsize="64" type="float" group="float"/>
+  <reg name="f29" bitsize="64" type="float" group="float"/>
+  <reg name="f30" bitsize="64" type="float" group="float"/>
+
+  <!-- Floating-Point Control Register -->
+  <reg name="fpcr" bitsize="64" type="int64" group="float"/>
+
+  <!-- Program Counter -->
+  <reg name="pc" bitsize="64" type="code_ptr"/>
+
+  <!-- Reserved Index for Former Virtual Register -->
+  <reg name="" bitsize="64" type="int64" save-restore="no"/>
+
+  <!-- PALcode Memory Slot -->
+  <reg name="unique" bitsize="64" type="int64" group="system"/>
+</feature>
diff --git a/gdb/features/alpha.c b/gdb/features/alpha.c
new file mode 100644
index 0000000..051ded8
--- /dev/null
+++ b/gdb/features/alpha.c
@@ -0,0 +1,84 @@
+/* THIS FILE IS GENERATED.  -*- buffer-read-only: t -*- vi:set ro:
+  Original: alpha.xml */
+
+#include "osabi.h"
+#include "target-descriptions.h"
+
+const struct target_desc *tdesc_alpha;
+static void
+initialize_tdesc_alpha (void)
+{
+  target_desc_up result = allocate_target_description ();
+  struct tdesc_feature *feature;
+
+  feature = tdesc_create_feature (result.get (), "org.gnu.gdb.alpha.core");
+  tdesc_create_reg (feature, "v0", 0, 1, NULL, 64, "int64");
+  tdesc_create_reg (feature, "t0", 1, 1, NULL, 64, "int64");
+  tdesc_create_reg (feature, "t1", 2, 1, NULL, 64, "int64");
+  tdesc_create_reg (feature, "t2", 3, 1, NULL, 64, "int64");
+  tdesc_create_reg (feature, "t3", 4, 1, NULL, 64, "int64");
+  tdesc_create_reg (feature, "t4", 5, 1, NULL, 64, "int64");
+  tdesc_create_reg (feature, "t5", 6, 1, NULL, 64, "int64");
+  tdesc_create_reg (feature, "t6", 7, 1, NULL, 64, "int64");
+  tdesc_create_reg (feature, "t7", 8, 1, NULL, 64, "int64");
+  tdesc_create_reg (feature, "s0", 9, 1, NULL, 64, "int64");
+  tdesc_create_reg (feature, "s1", 10, 1, NULL, 64, "int64");
+  tdesc_create_reg (feature, "s2", 11, 1, NULL, 64, "int64");
+  tdesc_create_reg (feature, "s3", 12, 1, NULL, 64, "int64");
+  tdesc_create_reg (feature, "s4", 13, 1, NULL, 64, "int64");
+  tdesc_create_reg (feature, "s5", 14, 1, NULL, 64, "int64");
+  tdesc_create_reg (feature, "fp", 15, 1, NULL, 64, "int64");
+  tdesc_create_reg (feature, "a0", 16, 1, NULL, 64, "int64");
+  tdesc_create_reg (feature, "a1", 17, 1, NULL, 64, "int64");
+  tdesc_create_reg (feature, "a2", 18, 1, NULL, 64, "int64");
+  tdesc_create_reg (feature, "a3", 19, 1, NULL, 64, "int64");
+  tdesc_create_reg (feature, "a4", 20, 1, NULL, 64, "int64");
+  tdesc_create_reg (feature, "a5", 21, 1, NULL, 64, "int64");
+  tdesc_create_reg (feature, "t8", 22, 1, NULL, 64, "int64");
+  tdesc_create_reg (feature, "t9", 23, 1, NULL, 64, "int64");
+  tdesc_create_reg (feature, "t10", 24, 1, NULL, 64, "int64");
+  tdesc_create_reg (feature, "t11", 25, 1, NULL, 64, "int64");
+  tdesc_create_reg (feature, "ra", 26, 1, NULL, 64, "int64");
+  tdesc_create_reg (feature, "t12", 27, 1, NULL, 64, "int64");
+  tdesc_create_reg (feature, "at", 28, 1, NULL, 64, "int64");
+  tdesc_create_reg (feature, "gp", 29, 1, NULL, 64, "data_ptr");
+  tdesc_create_reg (feature, "sp", 30, 1, NULL, 64, "data_ptr");
+  tdesc_create_reg (feature, "zero", 31, 0, NULL, 64, "int64");
+  tdesc_create_reg (feature, "f0", 32, 1, "float", 64, "float");
+  tdesc_create_reg (feature, "f1", 33, 1, "float", 64, "float");
+  tdesc_create_reg (feature, "f2", 34, 1, "float", 64, "float");
+  tdesc_create_reg (feature, "f3", 35, 1, "float", 64, "float");
+  tdesc_create_reg (feature, "f4", 36, 1, "float", 64, "float");
+  tdesc_create_reg (feature, "f5", 37, 1, "float", 64, "float");
+  tdesc_create_reg (feature, "f6", 38, 1, "float", 64, "float");
+  tdesc_create_reg (feature, "f7", 39, 1, "float", 64, "float");
+  tdesc_create_reg (feature, "f8", 40, 1, "float", 64, "float");
+  tdesc_create_reg (feature, "f9", 41, 1, "float", 64, "float");
+  tdesc_create_reg (feature, "f10", 42, 1, "float", 64, "float");
+  tdesc_create_reg (feature, "f11", 43, 1, "float", 64, "float");
+  tdesc_create_reg (feature, "f12", 44, 1, "float", 64, "float");
+  tdesc_create_reg (feature, "f13", 45, 1, "float", 64, "float");
+  tdesc_create_reg (feature, "f14", 46, 1, "float", 64, "float");
+  tdesc_create_reg (feature, "f15", 47, 1, "float", 64, "float");
+  tdesc_create_reg (feature, "f16", 48, 1, "float", 64, "float");
+  tdesc_create_reg (feature, "f17", 49, 1, "float", 64, "float");
+  tdesc_create_reg (feature, "f18", 50, 1, "float", 64, "float");
+  tdesc_create_reg (feature, "f19", 51, 1, "float", 64, "float");
+  tdesc_create_reg (feature, "f20", 52, 1, "float", 64, "float");
+  tdesc_create_reg (feature, "f21", 53, 1, "float", 64, "float");
+  tdesc_create_reg (feature, "f22", 54, 1, "float", 64, "float");
+  tdesc_create_reg (feature, "f23", 55, 1, "float", 64, "float");
+  tdesc_create_reg (feature, "f24", 56, 1, "float", 64, "float");
+  tdesc_create_reg (feature, "f25", 57, 1, "float", 64, "float");
+  tdesc_create_reg (feature, "f26", 58, 1, "float", 64, "float");
+  tdesc_create_reg (feature, "f27", 59, 1, "float", 64, "float");
+  tdesc_create_reg (feature, "f28", 60, 1, "float", 64, "float");
+  tdesc_create_reg (feature, "f29", 61, 1, "float", 64, "float");
+  tdesc_create_reg (feature, "f30", 62, 1, "float", 64, "float");
+  tdesc_create_reg (feature, "fpcr", 63, 1, "float", 64, "int64");
+  tdesc_create_reg (feature, "pc", 64, 1, NULL, 64, "code_ptr");
+  tdesc_create_reg (feature, "", 65, 0, NULL, 64, "int64");
+  tdesc_create_reg (feature, "unique", 66, 1, "system", 64, "int64");
+
+  tdesc_alpha = result.release ();
+}
diff --git a/gdb/features/alpha.xml b/gdb/features/alpha.xml
new file mode 100644
index 0000000..3ae0ab8
--- /dev/null
+++ b/gdb/features/alpha.xml
@@ -0,0 +1,11 @@
+<?xml version="1.0"?>
+<!-- Copyright (C) 2025 Free Software Foundation, Inc.
+
+     Copying and distribution of this file, with or without modification,
+     are permitted in any medium without royalty provided the copyright
+     notice and this notice are preserved.  -->
+
+<!DOCTYPE feature SYSTEM "gdb-target.dtd">
+<target version="1.0">
+  <xi:include href="alpha-core.xml"/>
+</target>