'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, 12 insertions, 25 deletions

diff --git a/gdb/ada-lang.c b/gdb/ada-lang.c
index be2f47a6bc..d1a39bcc46 100644
--- a/gdb/ada-lang.c
+++ b/gdb/ada-lang.c
@@ -4454,17 +4454,10 @@ ada_read_renaming_var_value (struct symbol *renaming_sym,
 			     const struct block *block)
 {
   const char *sym_name;
-  struct expression *expr;
-  struct value *value;
-  struct cleanup *old_chain = NULL;
 
   sym_name = SYMBOL_LINKAGE_NAME (renaming_sym);
-  expr = parse_exp_1 (&sym_name, 0, block, 0);
-  old_chain = make_cleanup (free_current_contents, &expr);
-  value = evaluate_expression (expr);
-
-  do_cleanups (old_chain);
-  return value;
+  expression_up expr = parse_exp_1 (&sym_name, 0, block, 0);
+  return evaluate_expression (expr.get ());
 }
 
 
@@ -12308,7 +12301,7 @@ struct ada_catchpoint_location
   /* The condition that checks whether the exception that was raised
      is the specific exception the user specified on catchpoint
      creation.  */
-  struct expression *excep_cond_expr;
+  expression_up excep_cond_expr;
 };
 
 /* Implement the DTOR method in the bp_location_ops structure for all
@@ -12319,7 +12312,7 @@ ada_catchpoint_location_dtor (struct bp_location *bl)
 {
   struct ada_catchpoint_location *al = (struct ada_catchpoint_location *) bl;
 
-  xfree (al->excep_cond_expr);
+  al->excep_cond_expr.reset ();
 }
 
 /* The vtable to be used in Ada catchpoint locations.  */
@@ -12371,7 +12364,7 @@ create_excep_cond_exprs (struct ada_catchpoint *c)
     {
       struct ada_catchpoint_location *ada_loc
 	= (struct ada_catchpoint_location *) bl;
-      struct expression *exp = NULL;
+      expression_up exp;
 
       if (!bl->shlib_disabled)
 	{
@@ -12380,26 +12373,20 @@ create_excep_cond_exprs (struct ada_catchpoint *c)
 	  s = cond_string;
 	  TRY
 	    {
-	      exp = parse_exp_1 (&s, bl->address,
-				 block_for_pc (bl->address), 0);
+	      exp = gdb::move (parse_exp_1 (&s, bl->address,
+					    block_for_pc (bl->address),
+					    0));
 	    }
 	  CATCH (e, RETURN_MASK_ERROR)
 	    {
 	      warning (_("failed to reevaluate internal exception condition "
 			 "for catchpoint %d: %s"),
 		       c->base.number, e.message);
-	      /* There is a bug in GCC on sparc-solaris when building with
-		 optimization which causes EXP to change unexpectedly
-		 (http://gcc.gnu.org/bugzilla/show_bug.cgi?id=56982).
-		 The problem should be fixed starting with GCC 4.9.
-		 In the meantime, work around it by forcing EXP back
-		 to NULL.  */
-	      exp = NULL;
 	    }
 	  END_CATCH
 	}
 
-      ada_loc->excep_cond_expr = exp;
+      ada_loc->excep_cond_expr = gdb::move (exp);
     }
 
   do_cleanups (old_chain);
@@ -12427,7 +12414,7 @@ allocate_location_exception (enum ada_exception_catchpoint_kind ex,
 {
   struct ada_catchpoint_location *loc;
 
-  loc = XNEW (struct ada_catchpoint_location);
+  loc = new ada_catchpoint_location ();
   init_bp_location (&loc->base, &ada_catchpoint_location_ops, self);
   loc->excep_cond_expr = NULL;
   return &loc->base;
@@ -12479,7 +12466,7 @@ should_stop_exception (const struct bp_location *bl)
       struct value *mark;
 
       mark = value_mark ();
-      stop = value_true (evaluate_expression (ada_loc->excep_cond_expr));
+      stop = value_true (evaluate_expression (ada_loc->excep_cond_expr.get ()));
       value_free_to_mark (mark);
     }
   CATCH (ex, RETURN_MASK_ALL)
@@ -13143,7 +13130,7 @@ create_ada_exception_catchpoint (struct gdbarch *gdbarch,
   struct symtab_and_line sal
     = ada_exception_sal (ex_kind, excep_string, &addr_string, &ops);
 
-  c = XNEW (struct ada_catchpoint);
+  c = new ada_catchpoint ();
   init_ada_exception_breakpoint (&c->base, gdbarch, sal, addr_string,
 				 ops, tempflag, disabled, from_tty);
   c->excep_string = excep_string;