[PATCH 106/203] Introduce unop_ind_operation

Tom Tromey
2021-01-01T21:48:45Z

This adds class unop_ind_operation, which implements UNOP_IND.

gdb/ChangeLog
2021-01-01 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.
---
gdb/ChangeLog | 9 +++++++++
gdb/ax-gdb.c | 8 ++++++++
gdb/eval.c | 45 +++++++++++++++++++++++++++++++++++++-----
gdb/expop.h | 54 +++++++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 111 insertions(+), 5 deletions(-)

diff --git a/gdb/ax-gdb.c b/gdb/ax-gdb.c
index c87b290397d..f7ab50f8cde 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 b7f816e28fe..cca88d49230 100644
--- a/gdb/eval.c
+++ b/gdb/eval.c
@@ -1812,9 +1812,9 @@ 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));
@@ -1824,8 +1824,8 @@ 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));
@@ -2949,7 +2949,7 @@ 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. */
@@ -3276,6 +3276,22 @@ scope_operation::evaluate_for_address (struct expression *exp,
return x;
}

+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)
@@ -3544,6 +3560,25 @@ 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 913988d7692..caac155295a 100644
--- a/gdb/expop.h
+++ b/gdb/expop.h
@@ -181,6 +181,10 @@ 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
{
@@ -1355,6 +1359,56 @@ 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 */
--
2.26.2