Implement UNOP_MEMVAL and UNOP_MEMVAL_TYPE

This adds class unop_memval_operation and unop_memval_type_operation,
which implement UNOP_MEMVAL and UNOP_MEMVAL_TYPE.

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

	* expop.h (class unop_memval_operation)
	(class unop_memval_type_operation): New.
	* eval.c (eval_op_memval): No longer static.
	(unop_memval_operation::evaluate_for_address)
	(unop_memval_type_operation::evaluate_for_address)
	(unop_memval_operation::evaluate_for_sizeof)
	(unop_memval_type_operation::evaluate_for_sizeof): New methods.
	* ax-gdb.c (unop_memval_operation::do_generate_ax)
	(unop_memval_type_operation::do_generate_ax): New methods.

4 files changed, 165 insertions, 1 deletions

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 94bcb64..f93f0f2 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,17 @@
 2021-03-08  Tom Tromey  <tom@tromey.com>
 
+	* expop.h (class unop_memval_operation)
+	(class unop_memval_type_operation): New.
+	* eval.c (eval_op_memval): No longer static.
+	(unop_memval_operation::evaluate_for_address)
+	(unop_memval_type_operation::evaluate_for_address)
+	(unop_memval_operation::evaluate_for_sizeof)
+	(unop_memval_type_operation::evaluate_for_sizeof): New methods.
+	* ax-gdb.c (unop_memval_operation::do_generate_ax)
+	(unop_memval_type_operation::do_generate_ax): New methods.
+
+2021-03-08  Tom Tromey  <tom@tromey.com>
+
 	* expop.h (class unop_alignof_operation): New.
 	* eval.c (eval_op_alignof): No longer static.
 
diff --git a/gdb/ax-gdb.c b/gdb/ax-gdb.c
index 756f4d7..6514e40 100644
--- a/gdb/ax-gdb.c
+++ b/gdb/ax-gdb.c
@@ -2514,6 +2514,46 @@ unop_sizeof_operation::do_generate_ax (struct expression *exp,
   value->type = builtin_type (ax->gdbarch)->builtin_int;
 }
 
+void
+unop_memval_operation::do_generate_ax (struct expression *exp,
+				       struct agent_expr *ax,
+				       struct axs_value *value,
+				       struct type *cast_type)
+{
+  std::get<0> (m_storage)->generate_ax (exp, ax, value);
+  /* If we have an axs_rvalue or an axs_lvalue_memory, then we
+     already have the right value on the stack.  For
+     axs_lvalue_register, we must convert.  */
+  if (value->kind == axs_lvalue_register)
+    require_rvalue (ax, value);
+
+  value->type = std::get<1> (m_storage);
+  value->kind = axs_lvalue_memory;
+}
+
+void
+unop_memval_type_operation::do_generate_ax (struct expression *exp,
+					    struct agent_expr *ax,
+					    struct axs_value *value,
+					    struct type *cast_type)
+{
+  struct value *val
+    = std::get<0> (m_storage)->evaluate (nullptr, exp,
+					 EVAL_AVOID_SIDE_EFFECTS);
+  struct type *type = value_type (val);
+
+  std::get<1> (m_storage)->generate_ax (exp, ax, value);
+
+  /* If we have an axs_rvalue or an axs_lvalue_memory, then we
+     already have the right value on the stack.  For
+     axs_lvalue_register, we must convert.  */
+  if (value->kind == axs_lvalue_register)
+    require_rvalue (ax, value);
+
+  value->type = type;
+  value->kind = axs_lvalue_memory;
+}
+
 }
 
 /* This handles the middle-to-right-side of code generation for binary
diff --git a/gdb/eval.c b/gdb/eval.c
index 3cf8bf1..2781e1d 100644
--- a/gdb/eval.c
+++ b/gdb/eval.c
@@ -1897,7 +1897,7 @@ eval_op_alignof (struct type *expect_type, struct expression *exp,
 
 /* A helper function for UNOP_MEMVAL.  */
 
-static struct value *
+struct value *
 eval_op_memval (struct type *expect_type, struct expression *exp,
 		enum noside noside,
 		struct value *arg1, struct type *type)
@@ -3333,6 +3333,25 @@ var_msym_value_operation::evaluate_for_address (struct expression *exp,
     return value_addr (val);
 }
 
+value *
+unop_memval_operation::evaluate_for_address (struct expression *exp,
+					     enum noside noside)
+{
+  return value_cast (lookup_pointer_type (std::get<1> (m_storage)),
+		     std::get<0> (m_storage)->evaluate (nullptr, exp, noside));
+}
+
+value *
+unop_memval_type_operation::evaluate_for_address (struct expression *exp,
+						  enum noside noside)
+{
+  value *typeval = std::get<0> (m_storage)->evaluate (nullptr, exp,
+						      EVAL_AVOID_SIDE_EFFECTS);
+  struct type *type = value_type (typeval);
+  return value_cast (lookup_pointer_type (type),
+		     std::get<1> (m_storage)->evaluate (nullptr, exp, noside));
+}
+
 }
 
 /* Evaluate like `evaluate_subexp' except coercing arrays to pointers.
@@ -3604,6 +3623,22 @@ unop_ind_base_operation::evaluate_for_sizeof (struct expression *exp,
   return value_from_longest (size_type, (LONGEST) TYPE_LENGTH (type));
 }
 
+value *
+unop_memval_operation::evaluate_for_sizeof (struct expression *exp,
+					    enum noside noside)
+{
+  return evaluate_subexp_for_sizeof_base (exp, std::get<1> (m_storage));
+}
+
+value *
+unop_memval_type_operation::evaluate_for_sizeof (struct expression *exp,
+						 enum noside noside)
+{
+  value *typeval = std::get<0> (m_storage)->evaluate (nullptr, exp,
+						      EVAL_AVOID_SIDE_EFFECTS);
+  return evaluate_subexp_for_sizeof_base (exp, value_type (typeval));
+}
+
 }
 
 /* Evaluate a subexpression of EXP, at index *POS, and return a value
diff --git a/gdb/expop.h b/gdb/expop.h
index 87e52ac..b808c0f 100644
--- a/gdb/expop.h
+++ b/gdb/expop.h
@@ -193,6 +193,10 @@ extern struct value *eval_op_alignof (struct type *expect_type,
 				      struct expression *exp,
 				      enum noside noside,
 				      struct value *arg1);
+extern struct value *eval_op_memval (struct type *expect_type,
+				     struct expression *exp,
+				     enum noside noside,
+				     struct value *arg1, struct type *type);
 
 namespace expr
 {
@@ -1636,6 +1640,79 @@ public:
   { return UNOP_ALIGNOF; }
 };
 
+/* Implement UNOP_MEMVAL.  */
+class unop_memval_operation
+  : public tuple_holding_operation<operation_up, struct type *>
+{
+public:
+
+  using tuple_holding_operation::tuple_holding_operation;
+
+  value *evaluate (struct type *expect_type,
+		   struct expression *exp,
+		   enum noside noside) override
+  {
+    value *val = std::get<0> (m_storage)->evaluate (expect_type, exp, noside);
+    return eval_op_memval (expect_type, exp, noside, val,
+			   std::get<1> (m_storage));
+  }
+
+  value *evaluate_for_sizeof (struct expression *exp,
+			      enum noside noside) override;
+
+  value *evaluate_for_address (struct expression *exp,
+			       enum noside noside) override;
+
+  enum exp_opcode opcode () const override
+  { return UNOP_MEMVAL; }
+
+protected:
+
+  void do_generate_ax (struct expression *exp,
+		       struct agent_expr *ax,
+		       struct axs_value *value,
+		       struct type *cast_type)
+    override;
+};
+
+/* Implement UNOP_MEMVAL_TYPE.  */
+class unop_memval_type_operation
+  : public tuple_holding_operation<operation_up, operation_up>
+{
+public:
+
+  using tuple_holding_operation::tuple_holding_operation;
+
+  value *evaluate (struct type *expect_type,
+		   struct expression *exp,
+		   enum noside noside) override
+  {
+    value *typeval
+      = std::get<0> (m_storage)->evaluate (expect_type, exp,
+					   EVAL_AVOID_SIDE_EFFECTS);
+    struct type *type = value_type (typeval);
+    value *val = std::get<1> (m_storage)->evaluate (expect_type, exp, noside);
+    return eval_op_memval (expect_type, exp, noside, val, type);
+  }
+
+  value *evaluate_for_sizeof (struct expression *exp,
+			      enum noside noside) override;
+
+  value *evaluate_for_address (struct expression *exp,
+			       enum noside noside) override;
+
+  enum exp_opcode opcode () const override
+  { return UNOP_MEMVAL_TYPE; }
+
+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 */