'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, 32 deletions

diff --git a/gdb/eval.c b/gdb/eval.c
index 00a107c..f30b8e1 100644
--- a/gdb/eval.c
+++ b/gdb/eval.c
@@ -95,14 +95,9 @@ evaluate_subexp (struct type *expect_type, struct expression *exp,
 CORE_ADDR
 parse_and_eval_address (const char *exp)
 {
-  struct expression *expr = parse_expression (exp);
-  CORE_ADDR addr;
-  struct cleanup *old_chain =
-    make_cleanup (free_current_contents, &expr);
-
-  addr = value_as_address (evaluate_expression (expr));
-  do_cleanups (old_chain);
-  return addr;
+  expression_up expr = parse_expression (exp);
+
+  return value_as_address (evaluate_expression (expr.get ()));
 }
 
 /* Like parse_and_eval_address, but treats the value of the expression
@@ -110,27 +105,17 @@ parse_and_eval_address (const char *exp)
 LONGEST
 parse_and_eval_long (const char *exp)
 {
-  struct expression *expr = parse_expression (exp);
-  LONGEST retval;
-  struct cleanup *old_chain =
-    make_cleanup (free_current_contents, &expr);
-
-  retval = value_as_long (evaluate_expression (expr));
-  do_cleanups (old_chain);
-  return (retval);
+  expression_up expr = parse_expression (exp);
+
+  return value_as_long (evaluate_expression (expr.get ()));
 }
 
 struct value *
 parse_and_eval (const char *exp)
 {
-  struct expression *expr = parse_expression (exp);
-  struct value *val;
-  struct cleanup *old_chain =
-    make_cleanup (free_current_contents, &expr);
+  expression_up expr = parse_expression (exp);
 
-  val = evaluate_expression (expr);
-  do_cleanups (old_chain);
-  return val;
+  return evaluate_expression (expr.get ());
 }
 
 /* Parse up to a comma (or to a closeparen)
@@ -140,14 +125,9 @@ parse_and_eval (const char *exp)
 struct value *
 parse_to_comma_and_eval (const char **expp)
 {
-  struct expression *expr = parse_exp_1 (expp, 0, (struct block *) 0, 1);
-  struct value *val;
-  struct cleanup *old_chain =
-    make_cleanup (free_current_contents, &expr);
+  expression_up expr = parse_exp_1 (expp, 0, (struct block *) 0, 1);
 
-  val = evaluate_expression (expr);
-  do_cleanups (old_chain);
-  return val;
+  return evaluate_expression (expr.get ());
 }
 
 /* Evaluate an expression in internal prefix form
@@ -3104,14 +3084,13 @@ struct type *
 parse_and_eval_type (char *p, int length)
 {
   char *tmp = (char *) alloca (length + 4);
-  struct expression *expr;
 
   tmp[0] = '(';
   memcpy (tmp + 1, p, length);
   tmp[length + 1] = ')';
   tmp[length + 2] = '0';
   tmp[length + 3] = '\0';
-  expr = parse_expression (tmp);
+  expression_up expr = parse_expression (tmp);
   if (expr->elts[0].opcode != UNOP_CAST)
     error (_("Internal error in eval_type."));
   return expr->elts[1].type;