gdb_find_feature() and gdb_find_feature_register() find registers.
gdb_read_register() actually reads registers.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
---
 include/exec/gdbstub.h | 29 +++++++++++++++++++++++++++++
 gdbstub/gdbstub.c      | 31 ++++++++++++++++++++++++++++++-
 2 files changed, 59 insertions(+), 1 deletion(-)

diff --git a/include/exec/gdbstub.h b/include/exec/gdbstub.h
index da9ddfe54c..12336cb600 100644
--- a/include/exec/gdbstub.h
+++ b/include/exec/gdbstub.h
@@ -111,6 +111,35 @@ void gdb_feature_builder_end(const GDBFeatureBuilder *builder);
  */
 const GDBFeature *gdb_find_static_feature(const char *xmlname);
 
+/**
+ * gdb_find_feature() - Find a feature associated with a CPU.
+ * @cpu: The CPU associated with the feature.
+ * @name: The feature's name.
+ *
+ * Return: The feature's number.
+ */
+int gdb_find_feature(CPUState *cpu, const char *name);
+
+/**
+ * gdb_find_feature_register() - Find a register associated with a CPU.
+ * @cpu: The CPU associated with the register.
+ * @feature: The feature's number returned by gdb_find_feature().
+ * @name: The register's name.
+ *
+ * Return: The register's number.
+ */
+int gdb_find_feature_register(CPUState *cpu, int feature, const char *name);
+
+/**
+ * gdb_read_register() - Read a register associated with a CPU.
+ * @cpu: The CPU associated with the register.
+ * @buf: The buffer that the read register will be appended to.
+ * @reg: The register's number returned by gdb_find_feature_register().
+ *
+ * Return: The number of read bytes.
+ */
+int gdb_read_register(CPUState *cpu, GByteArray *buf, int reg);
+
 void gdb_set_stop_cpu(CPUState *cpu);
 
 /* in gdbstub-xml.c, generated by scripts/feature_to_c.py */
diff --git a/gdbstub/gdbstub.c b/gdbstub/gdbstub.c
index 7d7d887817..ad62cb3f7a 100644
--- a/gdbstub/gdbstub.c
+++ b/gdbstub/gdbstub.c
@@ -490,7 +490,36 @@ const GDBFeature *gdb_find_static_feature(const char *xmlname)
     g_assert_not_reached();
 }
 
-static int gdb_read_register(CPUState *cpu, GByteArray *buf, int reg)
+int gdb_find_feature(CPUState *cpu, const char *name)
+{
+    GDBRegisterState *r;
+
+    for (guint i = 0; i < cpu->gdb_regs->len; i++) {
+        r = &g_array_index(cpu->gdb_regs, GDBRegisterState, i);
+        if (!strcmp(name, r->feature->name)) {
+            return i;
+        }
+    }
+
+    return -1;
+}
+
+int gdb_find_feature_register(CPUState *cpu, int feature, const char *name)
+{
+    GDBRegisterState *r;
+
+    r = &g_array_index(cpu->gdb_regs, GDBRegisterState, feature);
+
+    for (int i = 0; i < r->feature->num_regs; i++) {
+        if (r->feature->regs[i] && !strcmp(name, r->feature->regs[i])) {
+            return r->base_reg + i;
+        }
+    }
+
+    return -1;
+}
+
+int gdb_read_register(CPUState *cpu, GByteArray *buf, int reg)
 {
     CPUClass *cc = CPU_GET_CLASS(cpu);
     GDBRegisterState *r;
-- 
2.42.0