Introduce objc_msgcall_operation

This adds class objc_msgcall_operation, which implements
OP_OBJC_MSGCALL.

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

	* eval.c (objc_msgcall_operation::evaluate): New method.
	* c-exp.h (class objc_msgcall_operation): New.

3 files changed, 61 insertions, 0 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 4f6680e..37fe24a 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,10 @@
 2021-03-08  Tom Tromey  <tom@tromey.com>
 
+	* eval.c (objc_msgcall_operation::evaluate): New method.
+	* c-exp.h (class objc_msgcall_operation): New.
+
+2021-03-08  Tom Tromey  <tom@tromey.com>
+
 	* expop.h (class var_value_operation): New.
 	* eval.c (var_value_operation::evaluate)
 	(var_value_operation::evaluate_for_address)
diff --git a/gdb/c-exp.h b/gdb/c-exp.h
index dcb4557..2d224c8 100644
--- a/gdb/c-exp.h
+++ b/gdb/c-exp.h
@@ -88,6 +88,23 @@ public:
   { return OP_OBJC_SELECTOR; }
 };
 
+/* An Objective C message call.  */
+class objc_msgcall_operation
+  : public tuple_holding_operation<CORE_ADDR, operation_up,
+				   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_OBJC_MSGCALL; }
+};
+
 }/* namespace expr */
 
 #endif /* C_EXP_H */
diff --git a/gdb/eval.c b/gdb/eval.c
index 9d3b5ae..9196517 100644
--- a/gdb/eval.c
+++ b/gdb/eval.c
@@ -2436,6 +2436,45 @@ eval_multi_subscript (struct type *expect_type, struct expression *exp,
   return (arg1);
 }
 
+namespace expr
+{
+
+value *
+objc_msgcall_operation::evaluate (struct type *expect_type,
+				  struct expression *exp,
+				  enum noside noside)
+{
+  enum noside sub_no_side = EVAL_NORMAL;
+  struct type *selector_type = builtin_type (exp->gdbarch)->builtin_data_ptr;
+
+  if (noside == EVAL_AVOID_SIDE_EFFECTS)
+    sub_no_side = EVAL_NORMAL;
+  else
+    sub_no_side = noside;
+  value *target
+    = std::get<1> (m_storage)->evaluate (selector_type, exp, sub_no_side);
+
+  if (value_as_long (target) == 0)
+    sub_no_side = EVAL_AVOID_SIDE_EFFECTS;
+  else
+    sub_no_side = noside;
+  std::vector<operation_up> &args = std::get<2> (m_storage);
+  value **argvec = XALLOCAVEC (struct value *, args.size () + 3);
+  argvec[0] = nullptr;
+  argvec[1] = nullptr;
+  for (int i = 0; i < args.size (); ++i)
+    argvec[i + 2] = args[i]->evaluate_with_coercion (exp, sub_no_side);
+  argvec[args.size () + 2] = nullptr;
+
+  return eval_op_objc_msgcall (expect_type, exp, noside, std::
+			       get<0> (m_storage), target,
+			       gdb::make_array_view (argvec,
+						     args.size () + 3));
+}
+
+}
+
+
 struct value *
 evaluate_subexp_standard (struct type *expect_type,
 			  struct expression *exp, int *pos,