Introduce decltype_operation

This adds class decltype_operation, which implements OP_DECLTYPE.

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

	* expop.h (class decltype_operation): New.

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 89d3e6f9a744211931d41fe4240e3597669a43e6..5f9e2bc70cc2215cf28c6f6f38a8ae84e763ea08 100644 (file)
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,7 @@
+2021-03-08  Tom Tromey  <tom@tromey.com>
+
+       * expop.h (class decltype_operation): New.
+
 2021-03-08  Tom Tromey  <tom@tromey.com>
 
        * expop.h (class typeof_operation): New.

diff --git a/gdb/expop.h b/gdb/expop.h
index da7435918e2c648f75d0068a0a00e1392b08b52d..183137805f98afe68bba9cfd6ef6038c2528baab 100644 (file)
--- a/gdb/expop.h
+++ b/gdb/expop.h
@@ -1470,6 +1470,53 @@ public:
   { return OP_TYPEOF; }
 };
 
+/* Implement 'decltype'.  */
+class decltype_operation
+  : public maybe_constant_operation<operation_up>
+{
+public:
+
+  using maybe_constant_operation::maybe_constant_operation;
+
+  value *evaluate (struct type *expect_type,
+                  struct expression *exp,
+                  enum noside noside) override
+  {
+    if (noside == EVAL_SKIP)
+      return eval_skip_value (exp);
+    else if (noside == EVAL_AVOID_SIDE_EFFECTS)
+      {
+       value *result
+         = std::get<0> (m_storage)->evaluate (nullptr, exp,
+                                              EVAL_AVOID_SIDE_EFFECTS);
+       enum exp_opcode sub_op = std::get<0> (m_storage)->opcode ();
+       if (sub_op == BINOP_SUBSCRIPT
+           || sub_op == STRUCTOP_MEMBER
+           || sub_op == STRUCTOP_MPTR
+           || sub_op == UNOP_IND
+           || sub_op == STRUCTOP_STRUCT
+           || sub_op == STRUCTOP_PTR
+           || sub_op == OP_SCOPE)
+         {
+           struct type *type = value_type (result);
+
+           if (!TYPE_IS_REFERENCE (type))
+             {
+               type = lookup_lvalue_reference_type (type);
+               result = allocate_value (type);
+             }
+         }
+
+       return result;
+      }
+    else
+      error (_("Attempt to use a type as an expression"));
+  }
+
+  enum exp_opcode opcode () const override
+  { return OP_DECLTYPE; }
+};
+
 } /* namespace expr */
 
 #endif /* EXPOP_H */