[PATCH 115/203] Introduce op_this_operation

Tom Tromey
2021-01-01T21:48:51Z

This adds class op_this_operation, which implements OP_THIS.

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

* expop.h (class op_this_operation): New.
* ax-gdb.c (op_this_operation::do_generate_ax): New method.
---
gdb/ChangeLog | 5 +++++
gdb/ax-gdb.c | 25 +++++++++++++++++++++++++
gdb/expop.h | 27 +++++++++++++++++++++++++++
3 files changed, 57 insertions(+)

diff --git a/gdb/ax-gdb.c b/gdb/ax-gdb.c
index 6514e40cdbf..98edc6c0727 100644
--- a/gdb/ax-gdb.c
+++ b/gdb/ax-gdb.c
@@ -2554,6 +2554,31 @@ unop_memval_type_operation::do_generate_ax (struct expression *exp,
value->kind = axs_lvalue_memory;
}

+void
+op_this_operation::do_generate_ax (struct expression *exp,
+ struct agent_expr *ax,
+ struct axs_value *value,
+ struct type *cast_type)
+{
+ struct symbol *sym, *func;
+ const struct block *b;
+ const struct language_defn *lang;
+
+ b = block_for_pc (ax->scope);
+ func = block_linkage_function (b);
+ lang = language_def (func->language ());
+
+ sym = lookup_language_this (lang, b).symbol;
+ if (!sym)
+ error (_("no `%s' found"), lang->name_of_this ());
+
+ gen_var_ref (ax, value, sym);
+
+ if (value->optimized_out)
+ error (_("`%s' has been optimized out, cannot use"),
+ sym->print_name ());
+}
+
}

/* This handles the middle-to-right-side of code generation for binary
diff --git a/gdb/expop.h b/gdb/expop.h
index 867cd85ead5..394191ce6e5 100644
--- a/gdb/expop.h
+++ b/gdb/expop.h
@@ -1702,6 +1702,33 @@ class unop_memval_type_operation
override;
};

+/* Implement the 'this' expression. */
+class op_this_operation
+ : public tuple_holding_operation<>
+{
+public:
+
+ using tuple_holding_operation::tuple_holding_operation;
+
+ value *evaluate (struct type *expect_type,
+ struct expression *exp,
+ enum noside noside) override
+ {
+ return value_of_this (exp->language_defn);
+ }
+
+ enum exp_opcode opcode () const override
+ { return OP_THIS; }
+
+protected:
+
+ void do_generate_ax (struct expression *exp,
+ struct agent_expr *ax,
+ struct axs_value *value,
+ struct type *cast_type)
+ override;
+};
+
} /* namespace expr */

#endif /* EXPOP_H */
--
2.26.2