Introduce unop_ind_operation

This adds class unop_ind_operation, which implements UNOP_IND.

gdb/ChangeLog
2021-03-08  Tom Tromey  <tom@tromey.com>

	* expop.h (class unop_ind_base_operation)
	(class unop_ind_operation): New.
	* eval.c (eval_op_ind): No longer static.  Remove "op" parameter.
	(unop_ind_base_operation::evaluate_for_address)
	(unop_ind_base_operation::evaluate_for_sizeof): New method.
	* ax-gdb.c (gen_expr_unop) <case UNOP_IND>: New.

4 files changed, 111 insertions, 5 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 5824898..da7cd69 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,14 @@
 2021-03-08  Tom Tromey  <tom@tromey.com>
 
+	* expop.h (class unop_ind_base_operation)
+	(class unop_ind_operation): New.
+	* eval.c (eval_op_ind): No longer static.  Remove "op" parameter.
+	(unop_ind_base_operation::evaluate_for_address)
+	(unop_ind_base_operation::evaluate_for_sizeof): New method.
+	* ax-gdb.c (gen_expr_unop) <case UNOP_IND>: New.
+
+2021-03-08  Tom Tromey  <tom@tromey.com>
+
 	* expop.h (unop_incr_operation): New template.
 	(preinc_operation, predec_operation, postinc_operation)
 	(postdec_operation): New typedefs.
diff --git a/gdb/ax-gdb.c b/gdb/ax-gdb.c
index c87b290..f7ab50f 100644
--- a/gdb/ax-gdb.c
+++ b/gdb/ax-gdb.c
@@ -2736,6 +2736,14 @@ gen_expr_unop (struct expression *exp,
       gen_complement (ax, value);
       break;
 
+    case UNOP_IND:
+      lhs->generate_ax (exp, ax, value);
+      gen_usual_unary (ax, value);
+      if (!pointer_type (value->type))
+	error (_("Argument of unary `*' is not a pointer."));
+      gen_deref (value);
+      break;
+
     default:
       gdb_assert_not_reached ("invalid case in gen_expr_unop");
     }
diff --git a/gdb/eval.c b/gdb/eval.c
index 4f12c7b..1995d39 100644
--- a/gdb/eval.c
+++ b/gdb/eval.c
@@ -1827,9 +1827,9 @@ eval_op_lognot (struct type *expect_type, struct expression *exp,
 
 /* A helper function for UNOP_IND.  */
 
-static struct value *
+struct value *
 eval_op_ind (struct type *expect_type, struct expression *exp,
-	     enum noside noside, enum exp_opcode op,
+	     enum noside noside,
 	     struct value *arg1)
 {
   struct type *type = check_typedef (value_type (arg1));
@@ -1839,8 +1839,8 @@ eval_op_ind (struct type *expect_type, struct expression *exp,
 	     "to member without an object"));
   if (noside == EVAL_SKIP)
     return eval_skip_value (exp);
-  if (unop_user_defined_p (op, arg1))
-    return value_x_unop (arg1, op, noside);
+  if (unop_user_defined_p (UNOP_IND, arg1))
+    return value_x_unop (arg1, UNOP_IND, noside);
   else if (noside == EVAL_AVOID_SIDE_EFFECTS)
     {
       type = check_typedef (value_type (arg1));
@@ -2974,7 +2974,7 @@ evaluate_subexp_standard (struct type *expect_type,
       if (expect_type && expect_type->code () == TYPE_CODE_PTR)
 	expect_type = TYPE_TARGET_TYPE (check_typedef (expect_type));
       arg1 = evaluate_subexp (expect_type, exp, pos, noside);
-      return eval_op_ind (expect_type, exp, noside, op, arg1);
+      return eval_op_ind (expect_type, exp, noside, arg1);
 
     case UNOP_ADDR:
       /* C++: check for and handle pointer to members.  */
@@ -3302,6 +3302,22 @@ scope_operation::evaluate_for_address (struct expression *exp,
 }
 
 value *
+unop_ind_base_operation::evaluate_for_address (struct expression *exp,
+					       enum noside noside)
+{
+  value *x = std::get<0> (m_storage)->evaluate (nullptr, exp, noside);
+
+  /* We can't optimize out "&*" if there's a user-defined operator*.  */
+  if (unop_user_defined_p (UNOP_IND, x))
+    {
+      x = value_x_unop (x, UNOP_IND, noside);
+      return evaluate_subexp_for_address_base (exp, noside, x);
+    }
+
+  return coerce_array (x);
+}
+
+value *
 var_msym_value_operation::evaluate_for_address (struct expression *exp,
 						enum noside noside)
 {
@@ -3569,6 +3585,25 @@ subscript_operation::evaluate_for_sizeof (struct expression *exp,
   return operation::evaluate_for_sizeof (exp, noside);
 }
 
+value *
+unop_ind_base_operation::evaluate_for_sizeof (struct expression *exp,
+					      enum noside noside)
+{
+  value *val = std::get<0> (m_storage)->evaluate (nullptr, exp,
+						  EVAL_AVOID_SIDE_EFFECTS);
+  struct type *type = check_typedef (value_type (val));
+  if (type->code () != TYPE_CODE_PTR
+      && !TYPE_IS_REFERENCE (type)
+      && type->code () != TYPE_CODE_ARRAY)
+    error (_("Attempt to take contents of a non-pointer value."));
+  type = TYPE_TARGET_TYPE (type);
+  if (is_dynamic_type (type))
+    type = value_type (value_ind (val));
+  /* FIXME: This should be size_t.  */
+  struct type *size_type = builtin_type (exp->gdbarch)->builtin_int;
+  return value_from_longest (size_type, (LONGEST) TYPE_LENGTH (type));
+}
+
 }
 
 /* Evaluate a subexpression of EXP, at index *POS, and return a value
diff --git a/gdb/expop.h b/gdb/expop.h
index ec73109..4b1d65a 100644
--- a/gdb/expop.h
+++ b/gdb/expop.h
@@ -182,6 +182,10 @@ extern struct value *eval_op_postdec (struct type *expect_type,
 				      enum noside noside,
 				      enum exp_opcode op,
 				      struct value *arg1);
+extern struct value *eval_op_ind (struct type *expect_type,
+				  struct expression *exp,
+				  enum noside noside,
+				  struct value *arg1);
 
 namespace expr
 {
@@ -1366,6 +1370,56 @@ using postinc_operation
 using postdec_operation
      = unop_incr_operation<UNOP_POSTDECREMENT, eval_op_postdec>;
 
+/* Base class for implementations of UNOP_IND.  */
+class unop_ind_base_operation
+  : public tuple_holding_operation<operation_up>
+{
+public:
+
+  using tuple_holding_operation::tuple_holding_operation;
+
+  value *evaluate (struct type *expect_type,
+		   struct expression *exp,
+		   enum noside noside) override
+  {
+    if (expect_type != nullptr && expect_type->code () == TYPE_CODE_PTR)
+      expect_type = TYPE_TARGET_TYPE (check_typedef (expect_type));
+    value *val = std::get<0> (m_storage)->evaluate (expect_type, exp, noside);
+    return eval_op_ind (expect_type, exp, noside, val);
+  }
+
+  value *evaluate_for_address (struct expression *exp,
+			       enum noside noside) override;
+
+  value *evaluate_for_sizeof (struct expression *exp,
+			      enum noside noside) override;
+
+  enum exp_opcode opcode () const override
+  { return UNOP_IND; }
+};
+
+/* Ordinary UNOP_IND implementation.  */
+class unop_ind_operation
+  : public unop_ind_base_operation
+{
+public:
+
+  using unop_ind_base_operation::unop_ind_base_operation;
+
+protected:
+
+  void do_generate_ax (struct expression *exp,
+		       struct agent_expr *ax,
+		       struct axs_value *value,
+		       struct type *cast_type)
+    override
+  {
+    gen_expr_unop (exp, UNOP_IND,
+		   std::get<0> (this->m_storage).get (),
+		   ax, value);
+  }
+};
+
 } /* namespace expr */
 
 #endif /* EXPOP_H */