'struct expression *' -> gdb::unique_xmalloc_ptr<expression>

This patch makes parse_expression and friends return a unique_ptr
instead of raw pointer [1]:

  typedef gdb::unique_malloc_ptr<expression> expression_up;

and then adjusts the codebase throughout to stop using cleanups to
manage lifetime of expression pointers.

Whenever I found a structure owning an expression pointer, I made it
store a unique_ptr instead of a raw pointer, which then requires using
new/delete of the holding structure, instead of XNEW/xfree.

[1] - I'd like to set the rule that types named with an "_up" suffix
      are unique_ptr typedefs.

Note I used gdb::unique_xmalloc_ptr instead of gdb::unique_ptr, simply
because we still use xmalloc instead of new to allocate expression
objects.  Once that's changed, all we need to do is change the
expression_up typedef and the smart pointer will then call delete
instead of xfree.

gdb/ChangeLog:
2016-11-08  Pedro Alves  <palves@redhat.com>

	* ada-lang.c (ada_read_renaming_var_value): Use expression_up.
	(struct ada_catchpoint_location) <excep_cond_expr>: Now an
	expression_up.
	(ada_catchpoint_location_dtor): Reset excep_cond_expr instead of
	using xfree.
	(create_excep_cond_exprs): Use expression_up and gdb::move.
	(allocate_location_exception): Use new instead of XNEW.
	(should_stop_exception): Likewise.  Adjust to use expression_up.
	(create_ada_exception_catchpoint): Use new instead of XNEW.
	* ax-gdb.c (agent_eval_command_one): Use expression_up instead of
	cleanups.
	(maint_agent_printf_command): Use expression_up.
	* break-catch-sig.c (create_signal_catchpoint): Use new instead of
	XNEW.
	* break-catch-syscall.c (create_syscall_event_catchpoint):
	Likewise.
	* break-catch-throw.c (handle_gnu_v3_exceptions): Use new instead
	of XCNEW.  Use gdb::unique_ptr instead of cleanups.
	* breakpoint.c (set_breakpoint_condition, update_watchpoint)
	(parse_cmd_to_aexpr, watchpoint_check)
	(bpstat_check_breakpoint_conditions, watchpoint_locations_match):
	Adjust to use expression_up.
	(init_bp_location): Adjust.
	(free_bp_location): Use delete instead of xfree.
	(set_raw_breakpoint_without_location, set_raw_breakpoint)
	(add_solib_catchpoint, create_fork_vfork_event_catchpoint)
	(new_single_step_breakpoint, create_breakpoint_sal): Use new
	instead of XNEW.
	(find_condition_and_thread): Adjust to use expression_up.
	(create_breakpoint): Use new instead of XNEW.
	(dtor_watchpoint): Don't xfree expression pointers, they're
	unique_ptr's now.
	(insert_watchpoint, remove_watchpoint): Adjust.
	(watch_command_1): Use expression_up.  Use new instead of XCNEW.
	(catch_exec_command_1): Use new instead of XNEW.
	(bp_location_dtor): Don't xfree expression pointers, they're
	unique_ptr's now.
	(base_breakpoint_allocate_location)
	(strace_marker_create_breakpoints_sal): Use new instead of XNEW.
	(delete_breakpoint): Use delete instead of xfree.
	* breakpoint.h (struct bp_location) <cond>: Now an
	unique_ptr<expression> instead of a raw pointer.
	(struct watchpoint) <exp, cond_exp>: Likewise.
	* cli/cli-script.c (execute_control_command): Use expression_up
	instead of cleanups.
	* dtrace-probe.c (dtrace_process_dof_probe): Use expression_up.
	* eval.c (parse_and_eval_address, parse_and_eval_long)
	(parse_and_eval, parse_to_comma_and_eval, parse_and_eval_type):
	Use expression_up instead of cleanups.
	* expression.h (expression_up): New typedef.
	(parse_expression, parse_expression_with_language, parse_exp_1):
	Change return type to expression_up.
	* mi/mi-main.c (mi_cmd_data_evaluate_expression)
	(print_variable_or_computed): Use expression_up.
	* objc-lang.c (print_object_command): Use expression_up instead of
	cleanups.
	* parse.c (parse_exp_1, parse_exp_in_context)
	(parse_exp_in_context_1, parse_expression)
	(parse_expression_with_language): Return an expression_up instead
	of a raw pointer.
	(parse_expression_for_completion): Use expression_up.
	* printcmd.c (struct display) <exp>: Now an expression_up instead
	of a raw pointer.
	(print_command_1, output_command_const, set_command, x_command):
	Use expression_up instead of cleanups.
	(display_command): Likewise.  Use new instead of XNEW.
	(free_display): Use delete instead of xfree.
	(do_one_display): Adjust to use expression_up.
	* remote.c (remote_download_tracepoint): Likewise.
	* stack.c (return_command): Likewise.
	* tracepoint.c (validate_actionline, encode_actions_1): Use
	expression_up instead of cleanups.
	* typeprint.c (whatis_exp, maintenance_print_type): Likewise.
	* value.c (init_if_undefined_command): Likewise.
	* varobj.c (struct varobj_root) <exp>: Now an expression_up
	instead of a raw pointer.
	(varobj_create): Adjust.
	(varobj_set_value): Use an expression_up instead of cleanups.
	(new_root_variable): Use new instead of XNEW.
	(free_variable): Use delete instead of xfree.
	(value_of_root_1): Use std::swap.

1 files changed, 11 insertions, 20 deletions

diff --git a/gdb/varobj.c b/gdb/varobj.c
index fb1349a..81e897f 100644
--- a/gdb/varobj.c
+++ b/gdb/varobj.c
@@ -64,12 +64,12 @@ varobj_enable_pretty_printing (void)
 /* Data structures */
 
 /* Every root variable has one of these structures saved in its
-   varobj.  Members which must be free'd are noted.  */
+   varobj.  */
 struct varobj_root
 {
 
-  /* Alloc'd expression for this parent.  */
-  struct expression *exp;
+  /* The expression for this parent.  */
+  expression_up exp;
 
   /* Block for which this expression is valid.  */
   const struct block *valid_block;
@@ -379,13 +379,13 @@ varobj_create (char *objname,
          But if it fails, we still go on with a call to evaluate_type().  */
       TRY
 	{
-	  value = evaluate_expression (var->root->exp);
+	  value = evaluate_expression (var->root->exp.get ());
 	}
       CATCH (except, RETURN_MASK_ERROR)
 	{
 	  /* Error getting the value.  Try to at least get the
 	     right type.  */
-	  struct value *type_only_value = evaluate_type (var->root->exp);
+	  struct value *type_only_value = evaluate_type (var->root->exp.get ());
 
 	  var->type = value_type (type_only_value);
 	}
@@ -1051,7 +1051,6 @@ varobj_set_value (struct varobj *var, char *expression)
   /* The argument "expression" contains the variable's new value.
      We need to first construct a legal expression for this -- ugh!  */
   /* Does this cover all the bases?  */
-  struct expression *exp;
   struct value *value = NULL; /* Initialize to keep gcc happy.  */
   int saved_input_radix = input_radix;
   const char *s = expression;
@@ -1059,16 +1058,15 @@ varobj_set_value (struct varobj *var, char *expression)
   gdb_assert (varobj_editable_p (var));
 
   input_radix = 10;		/* ALWAYS reset to decimal temporarily.  */
-  exp = parse_exp_1 (&s, 0, 0, 0);
+  expression_up exp = parse_exp_1 (&s, 0, 0, 0);
   TRY
     {
-      value = evaluate_expression (exp);
+      value = evaluate_expression (exp.get ());
     }
 
   CATCH (except, RETURN_MASK_ERROR)
     {
       /* We cannot proceed without a valid expression.  */
-      xfree (exp);
       return 0;
     }
   END_CATCH
@@ -2095,7 +2093,7 @@ new_root_variable (void)
 {
   struct varobj *var = new_variable ();
 
-  var->root = XNEW (struct varobj_root);
+  var->root = new varobj_root ();
   var->root->lang_ops = NULL;
   var->root->exp = NULL;
   var->root->valid_block = NULL;
@@ -2126,12 +2124,8 @@ free_variable (struct varobj *var)
   varobj_clear_saved_item (var->dynamic);
   value_free (var->value);
 
-  /* Free the expression if this is a root variable.  */
   if (is_root_p (var))
-    {
-      xfree (var->root->exp);
-      xfree (var->root);
-    }
+    delete var->root;
 
   xfree (var->name);
   xfree (var->obj_name);
@@ -2296,7 +2290,7 @@ value_of_root_1 (struct varobj **var_handle)
          expression fails we want to just return NULL.  */
       TRY
 	{
-	  new_val = evaluate_expression (var->root->exp);
+	  new_val = evaluate_expression (var->root->exp.get ());
 	}
       CATCH (except, RETURN_MASK_ERROR)
 	{
@@ -2355,10 +2349,7 @@ value_of_root (struct varobj **var_handle, int *type_changed)
 	     button, for example).  Naturally, those locations are not
 	     correct in other frames, so update the expression.  */
 
-         struct expression *tmp_exp = var->root->exp;
-
-         var->root->exp = tmp_var->root->exp;
-         tmp_var->root->exp = tmp_exp;
+	  std::swap (var->root->exp, tmp_var->root->exp);
 
 	  varobj_delete (tmp_var, 0);
 	  *type_changed = 0;