Implement function call operations

This implement function call operations.

The current function call code relies on some very lengthy code
(evaluate_funcall is 398 lines...) to distinguish between the
different opcodes that might appear in the callee position.

Rather than try to replicate this, and have a function that tried to
dissect many different kinds of operation subclass, this patch instead
puts the work into the callee.  A new operation::evaluate_funcall
method is added, and then this is overridden in the classes that
require special treatment.

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

	* expression.h (class operation) <evaluate_funcall>: New methods.
	* expop.h (class scope_operation) <evaluate_funcall>: New method.
	(class var_value_operation) <evaluate_funcall>: New method.
	(class structop_base_operation) <evaluate_funcall>: New method.
	(class var_msym_value_operation) <evaluate_funcall>: New method.
	(class structop_member_base): New class.
	(class structop_member_operation): Derive from
	structop_member_base.
	(class structop_mptr_operation): Derive from
	structop_member_base.
	(class funcall_operation): New class.
	* eval.c (operation::evaluate_funcall)
	(var_value_operation::evaluate_funcall)
	(scope_operation::evaluate_funcall)
	(structop_member_base::evaluate_funcall)
	(structop_base_operation::evaluate_funcall): New methods.

1 files changed, 61 insertions, 3 deletions

diff --git a/gdb/expop.h b/gdb/expop.h
index 9b5c4ea..8ac7947 100644
--- a/gdb/expop.h
+++ b/gdb/expop.h
@@ -597,6 +597,11 @@ public:
   value *evaluate_for_address (struct expression *exp,
 			       enum noside noside) override;
 
+  value *evaluate_funcall (struct type *expect_type,
+			   struct expression *exp,
+			   enum noside noside,
+			   const std::vector<operation_up> &args) override;
+
   enum exp_opcode opcode () const override
   { return OP_SCOPE; }
 
@@ -634,6 +639,11 @@ public:
   value *evaluate_for_address (struct expression *exp, enum noside noside)
     override;
 
+  value *evaluate_funcall (struct type *expect_type,
+			   struct expression *exp,
+			   enum noside noside,
+			   const std::vector<operation_up> &args) override;
+
   enum exp_opcode opcode () const override
   { return OP_VAR_VALUE; }
 
@@ -702,6 +712,15 @@ public:
 			    struct expression *exp,
 			    enum noside noside) override;
 
+  value *evaluate_funcall (struct type *expect_type,
+			   struct expression *exp,
+			   enum noside noside,
+			   const std::vector<operation_up> &args) override
+  {
+    const char *name = std::get<0> (m_storage)->print_name ();
+    return operation::evaluate_funcall (expect_type, exp, noside, name, args);
+  }
+
   enum exp_opcode opcode () const override
   { return OP_VAR_MSYM_VALUE; }
 
@@ -974,6 +993,11 @@ public:
 					      EVAL_AVOID_SIDE_EFFECTS);
   }
 
+  value *evaluate_funcall (struct type *expect_type,
+			   struct expression *exp,
+			   enum noside noside,
+			   const std::vector<operation_up> &args) override;
+
 protected:
 
   using tuple_holding_operation::tuple_holding_operation;
@@ -1047,13 +1071,26 @@ protected:
   }
 };
 
-class structop_member_operation
+class structop_member_base
   : public tuple_holding_operation<operation_up, operation_up>
 {
 public:
 
   using tuple_holding_operation::tuple_holding_operation;
 
+  value *evaluate_funcall (struct type *expect_type,
+			   struct expression *exp,
+			   enum noside noside,
+			   const std::vector<operation_up> &args) override;
+};
+
+class structop_member_operation
+  : public structop_member_base
+{
+public:
+
+  using structop_member_base::structop_member_base;
+
   value *evaluate (struct type *expect_type,
 		   struct expression *exp,
 		   enum noside noside) override
@@ -1070,11 +1107,11 @@ public:
 };
 
 class structop_mptr_operation
-  : public tuple_holding_operation<operation_up, operation_up>
+  : public structop_member_base
 {
 public:
 
-  using tuple_holding_operation::tuple_holding_operation;
+  using structop_member_base::structop_member_base;
 
   value *evaluate (struct type *expect_type,
 		   struct expression *exp,
@@ -2071,6 +2108,27 @@ private:
 				       enum noside noside, int nargs);
 };
 
+/* A function call.  This holds the callee operation and the
+   arguments.  */
+class funcall_operation
+  : public tuple_holding_operation<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
+  {
+    return std::get<0> (m_storage)->evaluate_funcall (expect_type, exp, noside,
+						      std::get<1> (m_storage));
+  }
+
+  enum exp_opcode opcode () const override
+  { return OP_FUNCALL; }
+};
+
 } /* namespace expr */
 
 #endif /* EXPOP_H */