'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, 19 insertions, 28 deletions

diff --git a/gdb/tracepoint.c b/gdb/tracepoint.c
index e5c353c..e0ef6e8 100644
--- a/gdb/tracepoint.c
+++ b/gdb/tracepoint.c
@@ -701,7 +701,6 @@ void
 validate_actionline (const char *line, struct breakpoint *b)
 {
   struct cmd_list_element *c;
-  struct expression *exp = NULL;
   struct cleanup *old_chain = NULL;
   const char *tmp_p;
   const char *p;
@@ -755,9 +754,8 @@ validate_actionline (const char *line, struct breakpoint *b)
 	  for (loc = t->base.loc; loc; loc = loc->next)
 	    {
 	      p = tmp_p;
-	      exp = parse_exp_1 (&p, loc->address,
-				 block_for_pc (loc->address), 1);
-	      old_chain = make_cleanup (free_current_contents, &exp);
+	      expression_up exp = parse_exp_1 (&p, loc->address,
+					       block_for_pc (loc->address), 1);
 
 	      if (exp->elts[0].opcode == OP_VAR_VALUE)
 		{
@@ -780,8 +778,8 @@ validate_actionline (const char *line, struct breakpoint *b)
 	      /* We have something to collect, make sure that the expr to
 		 bytecode translator can handle it and that it's not too
 		 long.  */
-	      aexpr = gen_trace_for_expr (loc->address, exp, trace_string);
-	      make_cleanup_free_agent_expr (aexpr);
+	      aexpr = gen_trace_for_expr (loc->address, exp.get (), trace_string);
+	      old_chain = make_cleanup_free_agent_expr (aexpr);
 
 	      if (aexpr->len > MAX_AGENT_EXPR_LEN)
 		error (_("Expression is too complicated."));
@@ -809,15 +807,14 @@ validate_actionline (const char *line, struct breakpoint *b)
 	      p = tmp_p;
 
 	      /* Only expressions are allowed for this action.  */
-	      exp = parse_exp_1 (&p, loc->address,
-				 block_for_pc (loc->address), 1);
-	      old_chain = make_cleanup (free_current_contents, &exp);
+	      expression_up exp = parse_exp_1 (&p, loc->address,
+					       block_for_pc (loc->address), 1);
 
 	      /* We have something to evaluate, make sure that the expr to
 		 bytecode translator can handle it and that it's not too
 		 long.  */
-	      aexpr = gen_eval_for_expr (loc->address, exp);
-	      make_cleanup_free_agent_expr (aexpr);
+	      aexpr = gen_eval_for_expr (loc->address, exp.get ());
+	      old_chain = make_cleanup_free_agent_expr (aexpr);
 
 	      if (aexpr->len > MAX_AGENT_EXPR_LEN)
 		error (_("Expression is too complicated."));
@@ -1399,7 +1396,6 @@ encode_actions_1 (struct command_line *action,
 		  struct collection_list *stepping_list)
 {
   const char *action_exp;
-  struct expression *exp = NULL;
   int i;
   struct value *tempval;
   struct cmd_list_element *cmd;
@@ -1501,12 +1497,11 @@ encode_actions_1 (struct command_line *action,
 	      else
 		{
 		  unsigned long addr;
-		  struct cleanup *old_chain = NULL;
 		  struct cleanup *old_chain1 = NULL;
 
-		  exp = parse_exp_1 (&action_exp, tloc->address,
-				     block_for_pc (tloc->address), 1);
-		  old_chain = make_cleanup (free_current_contents, &exp);
+		  expression_up exp = parse_exp_1 (&action_exp, tloc->address,
+						   block_for_pc (tloc->address),
+						   1);
 
 		  switch (exp->elts[0].opcode)
 		    {
@@ -1528,13 +1523,13 @@ encode_actions_1 (struct command_line *action,
 
 		    case UNOP_MEMVAL:
 		      /* Safe because we know it's a simple expression.  */
-		      tempval = evaluate_expression (exp);
+		      tempval = evaluate_expression (exp.get ());
 		      addr = value_address (tempval);
 		      /* Initialize the TYPE_LENGTH if it is a typedef.  */
 		      check_typedef (exp->elts[1].type);
 		      add_memrange (collect, memrange_absolute, addr,
 				    TYPE_LENGTH (exp->elts[1].type));
-		      append_exp (exp, &collect->computed);
+		      append_exp (exp.get (), &collect->computed);
 		      break;
 
 		    case OP_VAR_VALUE:
@@ -1556,7 +1551,7 @@ encode_actions_1 (struct command_line *action,
 		      break;
 
 		    default:	/* Full-fledged expression.  */
-		      aexpr = gen_trace_for_expr (tloc->address, exp,
+		      aexpr = gen_trace_for_expr (tloc->address, exp.get (),
 						  trace_string);
 
 		      old_chain1 = make_cleanup_free_agent_expr (aexpr);
@@ -1589,10 +1584,9 @@ encode_actions_1 (struct command_line *action,
 			    }
 			}
 
-		      append_exp (exp, &collect->computed);
+		      append_exp (exp.get (), &collect->computed);
 		      break;
 		    }		/* switch */
-		  do_cleanups (old_chain);
 		}		/* do */
 	    }
 	  while (action_exp && *action_exp++ == ',');
@@ -1605,14 +1599,13 @@ encode_actions_1 (struct command_line *action,
 	      action_exp = skip_spaces_const (action_exp);
 
 		{
-		  struct cleanup *old_chain = NULL;
 		  struct cleanup *old_chain1 = NULL;
 
-		  exp = parse_exp_1 (&action_exp, tloc->address,
-				     block_for_pc (tloc->address), 1);
-		  old_chain = make_cleanup (free_current_contents, &exp);
+		  expression_up exp = parse_exp_1 (&action_exp, tloc->address,
+						   block_for_pc (tloc->address),
+						   1);
 
-		  aexpr = gen_eval_for_expr (tloc->address, exp);
+		  aexpr = gen_eval_for_expr (tloc->address, exp.get ());
 		  old_chain1 = make_cleanup_free_agent_expr (aexpr);
 
 		  ax_reqs (aexpr);
@@ -1622,8 +1615,6 @@ encode_actions_1 (struct command_line *action,
 		  /* Even though we're not officially collecting, add
 		     to the collect list anyway.  */
 		  add_aexpr (collect, aexpr);
-
-		  do_cleanups (old_chain);
 		}		/* do */
 	    }
 	  while (action_exp && *action_exp++ == ',');