More work on GDB interface

The following now works to run sail on every HVC call with hafnium

function gdb_init() -> unit = {
  // Connect to QEMU via GDB
  sail_gdb_qemu("");
  sail_gdb_symbol_file("hafnium.elf.sym");
  sail_gdb_send("break-insert sync_lower_exception")
}

function gdb() -> unit = {
  gdb_init();
  while true do {
    sail_gdb_send("exec-continue");
    sail_gdb_sync()
  }
}

1 files changed, 1 insertions, 0 deletions

diff --git a/src/interpreter.ml b/src/interpreter.ml
index dd322369..baa3f240 100644
--- a/src/interpreter.ml
+++ b/src/interpreter.ml
@@ -286,6 +286,7 @@ let rec step (E_aux (e_aux, annot) as orig_exp) =
   match e_aux with
   | E_block [] -> wrap (E_lit (L_aux (L_unit, Parse_ast.Unknown)))
   | E_block [exp] when is_value exp -> return exp
+  | E_block [E_aux (E_block _, _) as exp] -> return exp
   | E_block (exp :: exps) when is_value exp -> wrap (E_block exps)
   | E_block (exp :: exps) ->
      step exp >>= fun exp' -> wrap (E_block (exp' :: exps))