[PATCH 100/203] Introduce subscript_operation

Tom Tromey
2021-01-01T21:48:39Z

This adds class subscript_operation, which implements BINOP_SUBSCRIPT.

gdb/ChangeLog
2021-01-01 Tom Tromey <tom@tromey.com>

* expop.h (class subscript_operation): New.
* eval.c (eval_op_subscript): No longer static.
---
gdb/ChangeLog | 5 +++++
gdb/eval.c | 35 ++++++++++++++++++++++++++++++++++-
gdb/expop.h | 16 ++++++++++++++++
3 files changed, 55 insertions(+), 1 deletion(-)

diff --git a/gdb/eval.c b/gdb/eval.c
index 282abc910ce..e67842dea57 100644
--- a/gdb/eval.c
+++ b/gdb/eval.c
@@ -1543,7 +1543,7 @@ eval_op_binary (struct type *expect_type, struct expression *exp,

/* A helper function for BINOP_SUBSCRIPT. */

-static struct value *
+struct value *
eval_op_subscript (struct type *expect_type, struct expression *exp,
enum noside noside, enum exp_opcode op,
struct value *arg1, struct value *arg2)
@@ -3511,6 +3511,39 @@ var_msym_value_operation::evaluate_for_sizeof (struct expression *exp,
return value_from_longest (size_type, TYPE_LENGTH (type));
}

+value *
+subscript_operation::evaluate_for_sizeof (struct expression *exp,
+ enum noside noside)
+{
+ if (noside == EVAL_NORMAL)
+ {
+ 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_ARRAY)
+ {
+ type = check_typedef (TYPE_TARGET_TYPE (type));
+ if (type->code () == TYPE_CODE_ARRAY)
+ {
+ type = type->index_type ();
+ /* Only re-evaluate the right hand side if the resulting type
+ is a variable length type. */
+ if (type->bounds ()->flag_bound_evaluated)
+ {
+ val = evaluate (nullptr, exp, EVAL_NORMAL);
+ /* 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 (value_type (val)));
+ }
+ }
+ }
+ }
+
+ return operation::evaluate_for_sizeof (exp, noside);
+}
+
}

/* Evaluate a subexpression of EXP, at index *POS, and return a value
diff --git a/gdb/expop.h b/gdb/expop.h
index f4a33f491e3..556ceaa1e87 100644
--- a/gdb/expop.h
+++ b/gdb/expop.h
@@ -99,6 +99,11 @@ extern struct value *eval_op_binary (struct type *expect_type,
struct expression *exp,
enum noside noside, enum exp_opcode op,
struct value *arg1, struct value *arg2);
+extern struct value *eval_op_subscript (struct type *expect_type,
+ struct expression *exp,
+ enum noside noside, enum exp_opcode op,
+ struct value *arg1,
+ struct value *arg2);

namespace expr
{
@@ -1101,6 +1106,17 @@ using bitwise_ior_operation
using bitwise_xor_operation
= usual_ax_binop_operation<BINOP_BITWISE_XOR, eval_op_binary>;

+class subscript_operation
+ : public usual_ax_binop_operation<BINOP_SUBSCRIPT, eval_op_subscript>
+{
+public:
+ using usual_ax_binop_operation<BINOP_SUBSCRIPT,
+ eval_op_subscript>::usual_ax_binop_operation;
+
+ value *evaluate_for_sizeof (struct expression *exp,
+ enum noside noside) override;
+};
+
} /* namespace expr */

#endif /* EXPOP_H */
--
2.26.2