This is the mail archive of the
gcc-patches@gcc.gnu.org
mailing list for the GCC project.
[PATCH v2 1/4] ada: Generate warning on useless 'Unchecked_Access with -gnatw.u
- From: Samuel Tardieu <sam at rfc1149 dot net>
- To: gcc-patches at gcc dot gnu dot org
- Date: Mon, 5 Nov 2007 21:37:22 +0100
- Subject: [PATCH v2 1/4] ada: Generate warning on useless 'Unchecked_Access with -gnatw.u
- Organisation: RFC1149 (see http://www.rfc1149.net/)
New version of the -gnatw.u warning with more RTS files cleaned up,
usage added and enabling of this warning in -gnatg.
gcc/ada/
* opt.ads: New warning Warn_On_Useless_Unchecked_Access.
* sem_attr.adb (Resolve_Attribute): Check for unnecessary use
of 'Unchecked_Access when 'Access could safely be used. If
Warn_On_Useless_Unchecked_Access is True, post a warning.
* sem_warn.adb (Set_Dot_Warning_Switch): Activate/deactivate
Warn_On_Useless_Unchecked_Access on -gnatw.u/-gnatw.U.
(Set_Warning_Switch): Activate/deactivate this warning
on -gnatwa/-gnatwA.
* switch-c.adb (Scan_Front_End_Switches): Activate
Warn_On_Useless_Unchecked_Access on -gnatg.
* usage.adb (Usage): Document -gnatw.u and -gnatw.U.
---
gcc/ada/opt.ads | 6 ++++++
gcc/ada/sem_attr.adb | 22 ++++++++++++++++++++++
gcc/ada/sem_warn.adb | 8 ++++++++
gcc/ada/switch-c.adb | 37 +++++++++++++++++++------------------
gcc/ada/usage.adb | 4 ++++
5 files changed, 59 insertions(+), 18 deletions(-)
diff --git a/gcc/ada/opt.ads b/gcc/ada/opt.ads
index 00a9cef..8e118f3 100644
--- a/gcc/ada/opt.ads
+++ b/gcc/ada/opt.ads
@@ -1258,6 +1258,12 @@ package Opt is
-- which have a record representation clause but this component does not
-- have a component clause. The default is that this warning is disabled.
+ Warn_On_Useless_Unchecked_Access : Boolean := False;
+ -- GNAT
+ -- Set to True to generate warnings on use of X'Unchecked_Access where
+ -- X'Access would have been legitimate. The default is that this warning
+ -- is disabled.
+
type Warning_Mode_Type is (Suppress, Normal, Treat_As_Error);
Warning_Mode : Warning_Mode_Type := Normal;
-- GNAT, GNATBIND
diff --git a/gcc/ada/sem_attr.adb b/gcc/ada/sem_attr.adb
index ce66987..0056024 100644
--- a/gcc/ada/sem_attr.adb
+++ b/gcc/ada/sem_attr.adb
@@ -7673,6 +7673,28 @@ package body Sem_Attr is
Accessibility_Message;
return;
end if;
+
+ -- Check whether Access could have been used instead of
+ -- Unchecked_Access. The check is disabled:
+ -- - when compiling a generic because the
+ -- accessibility level may not be known if, for
+ -- example, the instantiation happens in a local
+ -- declaration;
+ -- - when compiling an instance, as Access could be
+ -- permitted only in this particular case and
+ -- forbidden in others.
+
+ if Attr_Id = Attribute_Unchecked_Access
+ and then Warn_On_Useless_Unchecked_Access
+ and then not Inside_A_Generic
+ and then not In_Instance
+ and then Comes_From_Source (P)
+ and then (Object_Access_Level (P) <= Type_Access_Level (Btyp)
+ or else Ekind (Btyp) = E_Anonymous_Access_Type)
+ then
+ Error_Msg_F
+ ("?''Access attribute could be used here", P);
+ end if;
end if;
if Ekind (Btyp) = E_Access_Protected_Subprogram_Type
diff --git a/gcc/ada/sem_warn.adb b/gcc/ada/sem_warn.adb
index 65ea957..53dd04d 100644
--- a/gcc/ada/sem_warn.adb
+++ b/gcc/ada/sem_warn.adb
@@ -2542,6 +2542,12 @@ package body Sem_Warn is
when 'R' =>
Warn_On_Object_Renames_Function := False;
+ when 'u' =>
+ Warn_On_Useless_Unchecked_Access := True;
+
+ when 'U' =>
+ Warn_On_Useless_Unchecked_Access := False;
+
when 'x' =>
Warn_On_Non_Local_Exception := True;
@@ -2584,6 +2590,7 @@ package body Sem_Warn is
Warn_On_Unchecked_Conversion := True;
Warn_On_Unrecognized_Pragma := True;
Warn_On_Unrepped_Components := True;
+ Warn_On_Useless_Unchecked_Access := True;
when 'A' =>
Check_Unreferenced := False;
@@ -2611,6 +2618,7 @@ package body Sem_Warn is
Warn_On_Unchecked_Conversion := False;
Warn_On_Unrecognized_Pragma := False;
Warn_On_Unrepped_Components := False;
+ Warn_On_Useless_Unchecked_Access := False;
when 'b' =>
Warn_On_Bad_Fixed_Value := True;
diff --git a/gcc/ada/switch-c.adb b/gcc/ada/switch-c.adb
index 76c47f2..50a100a 100644
--- a/gcc/ada/switch-c.adb
+++ b/gcc/ada/switch-c.adb
@@ -473,24 +473,25 @@ package body Switch.C is
-- Set default warnings for -gnatg
- Check_Unreferenced := True;
- Check_Unreferenced_Formals := True;
- Check_Withs := True;
- Constant_Condition_Warnings := True;
- Implementation_Unit_Warnings := True;
- Ineffective_Inline_Warnings := True;
- Warn_On_Assumed_Low_Bound := True;
- Warn_On_Bad_Fixed_Value := True;
- Warn_On_Constant := True;
- Warn_On_Export_Import := True;
- Warn_On_Modified_Unread := True;
- Warn_On_No_Value_Assigned := True;
- Warn_On_Non_Local_Exception := False;
- Warn_On_Obsolescent_Feature := True;
- Warn_On_Redundant_Constructs := True;
- Warn_On_Object_Renames_Function := True;
- Warn_On_Unchecked_Conversion := True;
- Warn_On_Unrecognized_Pragma := True;
+ Check_Unreferenced := True;
+ Check_Unreferenced_Formals := True;
+ Check_Withs := True;
+ Constant_Condition_Warnings := True;
+ Implementation_Unit_Warnings := True;
+ Ineffective_Inline_Warnings := True;
+ Warn_On_Assumed_Low_Bound := True;
+ Warn_On_Bad_Fixed_Value := True;
+ Warn_On_Constant := True;
+ Warn_On_Export_Import := True;
+ Warn_On_Modified_Unread := True;
+ Warn_On_No_Value_Assigned := True;
+ Warn_On_Non_Local_Exception := False;
+ Warn_On_Obsolescent_Feature := True;
+ Warn_On_Redundant_Constructs := True;
+ Warn_On_Object_Renames_Function := True;
+ Warn_On_Unchecked_Conversion := True;
+ Warn_On_Unrecognized_Pragma := True;
+ Warn_On_Useless_Unchecked_Access := True;
Set_GNAT_Style_Check_Options;
diff --git a/gcc/ada/usage.adb b/gcc/ada/usage.adb
index ae5ee42..9501758 100644
--- a/gcc/ada/usage.adb
+++ b/gcc/ada/usage.adb
@@ -421,6 +421,10 @@ begin
Write_Line (" T* turn off warnings for tracking deleted code");
Write_Line (" u turn on warnings for unused entity");
Write_Line (" U* turn off warnings for unused entity");
+ Write_Line (" .u turn on warnings for unnecessary " &
+ "unchecked access");
+ Write_Line (" .U turn off warnings for unnecessary " &
+ "unchecked access");
Write_Line (" v* turn on warnings for unassigned variable");
Write_Line (" V turn off warnings for unassigned variable");
Write_Line (" w* turn on warnings for wrong low bound assumption");
--
1.5.3.5