Implement DAP variables, scopes, and evaluate requests

The DAP code already claimed to implement "scopes" and "evaluate", but
this wasn't done completely correctly.  This patch implements these
and also implements the "variables" request.

After this patch, variables and scopes correctly report their
sub-structure.  This also interfaces with the gdb pretty-printer API,
so the output of pretty-printers is available.

1 files changed, 35 insertions, 0 deletions

diff --git a/gdb/testsuite/gdb.dap/scopes.c b/gdb/testsuite/gdb.dap/scopes.c
new file mode 100644
index 0000000..7b35036
--- /dev/null
+++ b/gdb/testsuite/gdb.dap/scopes.c
@@ -0,0 +1,35 @@
+/* Copyright 2023 Free Software Foundation, Inc.
+
+   This file is part of GDB.
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 3 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+struct dei_struct
+{
+  int x;
+  int more[5];
+};
+
+int main ()
+{
+  struct dei_struct dei = { 2, { 3, 5, 7, 11, 13 } };
+
+  static int scalar = 23;
+
+  {
+    const char *inner = "inner block";
+
+    return 0;			/* BREAK */
+  }
+}