Introduce class adl_func_operation

This adds class adl_func_operation, which implements
argument-dependent lookup function calls.

Other function calls will be handled in a different way.  However,
because ADL calls were created in a single spot in the C++ parser, and
because they had different semantics from the other cases, it was
convenient to treat them specially.

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

	* expop.h (class adl_func_operation): New.
	* eval.c (adl_func_operation::evaluate): New method.

gdb/ChangeLog

@@ -1,3 +1,8 @@
+2021-03-08  Tom Tromey  <tom@tromey.com>
+
+	* expop.h (class adl_func_operation): New.
+	* eval.c (adl_func_operation::evaluate): New method.
+
 2021-03-08  Tom Tromey  <tom@tromey.com>
 
 	* ada-lang.c (ada_unop_in_range): No longer static.

gdb/eval.c

@@ -2549,6 +2549,29 @@ logical_or_operation::evaluate (struct type *expect_type,
     }
 }
 
+value *
+adl_func_operation::evaluate (struct type *expect_type,
+			      struct expression *exp,
+			      enum noside noside)
+{
+  std::vector<operation_up> &arg_ops = std::get<2> (m_storage);
+  std::vector<value *> args (arg_ops.size ());
+  for (int i = 0; i < arg_ops.size (); ++i)
+    args[i] = arg_ops[i]->evaluate_with_coercion (exp, noside);
+
+  struct symbol *symp;
+  find_overload_match (args, std::get<0> (m_storage).c_str (),
+		       NON_METHOD,
+		       nullptr, nullptr,
+		       nullptr, &symp, nullptr, 0, noside);
+  if (SYMBOL_TYPE (symp)->code () == TYPE_CODE_ERROR)
+    error_unknown_type (symp->print_name ());
+  value *callee = evaluate_var_value (noside, std::get<1> (m_storage), symp);
+  return evaluate_subexp_do_call (exp, noside, callee, args,
+				  nullptr, expect_type);
+
+}
+
 }
 
 struct value *

gdb/expop.h

@@ -2030,6 +2030,25 @@ protected:
     override;
 };
 
+/* This class implements ADL (aka Koenig) function calls for C++.  It
+   holds the name of the function to call, the block in which the
+   lookup should be done, and a vector of arguments.  */
+class adl_func_operation
+  : public tuple_holding_operation<std::string, const block *,
+				   std::vector<operation_up>>
+{
+public:
+
+  using tuple_holding_operation::tuple_holding_operation;
+
+  value *evaluate (struct type *expect_type,
+		   struct expression *exp,
+		   enum noside noside) override;
+
+  enum exp_opcode opcode () const override
+  { return OP_ADL_FUNC; }
+};
+
 } /* namespace expr */
 
 #endif /* EXPOP_H */