This patch catches two syntax errors related to the use of null items in aspect
or pragma [Refined_]Depends. The patch also streamlines the error messages of
various aspects or pragmas that deal with null and non-null items.
------------
-- Source --
------------
-- depends_illegal.ads
package Depends_Illegal is
procedure P1 (Par1 : Integer)
with Depends => (null =>+ Par1);
procedure P2 (Par1 : Integer ; Par2 : out Integer)
with Depends => (Par2 => (Par1, null));
end Depends_Illegal;
----------------------------
-- Compilation and output --
----------------------------
$ gcc -c -gnatd.V depends_legal.ads
depends_illegal.ads:3:24: useless dependence, null depends on itself
depends_illegal.ads:6:39: cannot mix null and non-null dependency items
Tested on x86_64-pc-linux-gnu, committed on trunk
2013-10-14 Hristian Kirtchev <[email protected]>
* sem_prag.adb (Analyze_Dependency_Clause): Add new local variable
Non_Null_Output_Seen. Update the call to Analyze_Input_Output.
(Analyze_Input_Item): Streamline the detection mechanism of null and
non-null items.
(Analyze_Input_List): Add new local variable
Non_Null_Input_Seen. Update all calls to Analyze_Input_Output.
(Analyze_Input_Output): Add new formal parameter Non_Null_Seen
and update the related comment on usage. Update the
recursive call to itself. Attribute 'Result is now treated
as a non-null item. Detect mixes of null and non-null items.
(Analyze_Initialization_Item): Streamline the detection mechanism
of null and non-null items.
Index: sem_prag.adb
===================================================================
--- sem_prag.adb (revision 203551)
+++ sem_prag.adb (working copy)
@@ -555,12 +555,13 @@
-- Verify the legality of a single input list
procedure Analyze_Input_Output
- (Item : Node_Id;
- Is_Input : Boolean;
- Self_Ref : Boolean;
- Top_Level : Boolean;
- Seen : in out Elist_Id;
- Null_Seen : in out Boolean);
+ (Item : Node_Id;
+ Is_Input : Boolean;
+ Self_Ref : Boolean;
+ Top_Level : Boolean;
+ Seen : in out Elist_Id;
+ Null_Seen : in out Boolean;
+ Non_Null_Seen : in out Boolean);
-- Verify the legality of a single input or output item. Flag
-- Is_Input should be set whenever Item is an input, False when it
-- denotes an output. Flag Self_Ref should be set when the item is an
@@ -568,7 +569,8 @@
-- be set whenever Item appears immediately within an input or output
-- list. Seen is a collection of all abstract states, variables and
-- formals processed so far. Flag Null_Seen denotes whether a null
- -- input or output has been encountered.
+ -- input or output has been encountered. Flag Non_Null_Seen denotes
+ -- whether a non-null input or output has been encountered.
------------------------
-- Analyze_Input_List --
@@ -579,8 +581,9 @@
-- A list containing the entities of all inputs that appear in the
-- current input list.
- Null_Input_Seen : Boolean := False;
- -- A flag used to track the legality of a null input
+ Non_Null_Input_Seen : Boolean := False;
+ Null_Input_Seen : Boolean := False;
+ -- Flags used to check the legality of an input list
Input : Node_Id;
@@ -596,12 +599,13 @@
Input := First (Expressions (Inputs));
while Present (Input) loop
Analyze_Input_Output
- (Item => Input,
- Is_Input => True,
- Self_Ref => False,
- Top_Level => False,
- Seen => Inputs_Seen,
- Null_Seen => Null_Input_Seen);
+ (Item => Input,
+ Is_Input => True,
+ Self_Ref => False,
+ Top_Level => False,
+ Seen => Inputs_Seen,
+ Null_Seen => Null_Input_Seen,
+ Non_Null_Seen => Non_Null_Input_Seen);
Next (Input);
end loop;
@@ -614,12 +618,13 @@
else
Analyze_Input_Output
- (Item => Inputs,
- Is_Input => True,
- Self_Ref => False,
- Top_Level => False,
- Seen => Inputs_Seen,
- Null_Seen => Null_Input_Seen);
+ (Item => Inputs,
+ Is_Input => True,
+ Self_Ref => False,
+ Top_Level => False,
+ Seen => Inputs_Seen,
+ Null_Seen => Null_Input_Seen,
+ Non_Null_Seen => Non_Null_Input_Seen);
end if;
-- Detect an illegal dependency clause of the form
@@ -638,12 +643,13 @@
--------------------------
procedure Analyze_Input_Output
- (Item : Node_Id;
- Is_Input : Boolean;
- Self_Ref : Boolean;
- Top_Level : Boolean;
- Seen : in out Elist_Id;
- Null_Seen : in out Boolean)
+ (Item : Node_Id;
+ Is_Input : Boolean;
+ Self_Ref : Boolean;
+ Top_Level : Boolean;
+ Seen : in out Elist_Id;
+ Null_Seen : in out Boolean;
+ Non_Null_Seen : in out Boolean)
is
Is_Output : constant Boolean := not Is_Input;
Grouped : Node_Id;
@@ -666,12 +672,13 @@
Grouped := First (Expressions (Item));
while Present (Grouped) loop
Analyze_Input_Output
- (Item => Grouped,
- Is_Input => Is_Input,
- Self_Ref => Self_Ref,
- Top_Level => False,
- Seen => Seen,
- Null_Seen => Null_Seen);
+ (Item => Grouped,
+ Is_Input => Is_Input,
+ Self_Ref => Self_Ref,
+ Top_Level => False,
+ Seen => Seen,
+ Null_Seen => Null_Seen,
+ Non_Null_Seen => Non_Null_Seen);
Next (Grouped);
end loop;
@@ -683,6 +690,7 @@
-- Process Function'Result in the context of a dependency clause
elsif Is_Attribute_Result (Item) then
+ Non_Null_Seen := True;
-- It is sufficent to analyze the prefix of 'Result in order to
-- establish legality of the attribute.
@@ -707,6 +715,10 @@
elsif Is_Input then
Error_Msg_N ("function result cannot act as input", Item);
+ elsif Null_Seen then
+ Error_Msg_N
+ ("cannot mix null and non-null dependency items", Item);
+
else
Result_Seen := True;
end if;
@@ -719,19 +731,39 @@
if Null_Seen then
Error_Msg_N
("multiple null dependency relations not allowed", Item);
+
+ elsif Non_Null_Seen then
+ Error_Msg_N
+ ("cannot mix null and non-null dependency items", Item);
+
else
Null_Seen := True;
- if Is_Output and then not Is_Last then
- Error_Msg_N
- ("null output list must be the last clause in a "
- & "dependency relation", Item);
+ if Is_Output then
+ if not Is_Last then
+ Error_Msg_N
+ ("null output list must be the last clause in a "
+ & "dependency relation", Item);
+
+ -- Catch a useless dependence of the form:
+ -- null =>+ ...
+
+ elsif Self_Ref then
+ Error_Msg_N
+ ("useless dependence, null depends on itself", Item);
+ end if;
end if;
end if;
-- Default case
else
+ Non_Null_Seen := True;
+
+ if Null_Seen then
+ Error_Msg_N ("cannot mix null and non-null items", Item);
+ end if;
+
Analyze (Item);
-- Find the entity of the item. If this is a renaming, climb
@@ -845,6 +877,9 @@
Output : Node_Id;
Self_Ref : Boolean;
+ Non_Null_Output_Seen : Boolean := False;
+ -- Flag used to check the legality of an output list
+
-- Start of processing for Analyze_Dependency_Clause
begin
@@ -864,12 +899,13 @@
Output := First (Choices (Clause));
while Present (Output) loop
Analyze_Input_Output
- (Item => Output,
- Is_Input => False,
- Self_Ref => Self_Ref,
- Top_Level => True,
- Seen => All_Outputs_Seen,
- Null_Seen => Null_Output_Seen);
+ (Item => Output,
+ Is_Input => False,
+ Self_Ref => Self_Ref,
+ Top_Level => True,
+ Seen => All_Outputs_Seen,
+ Null_Seen => Null_Output_Seen,
+ Non_Null_Seen => Non_Null_Output_Seen);
Next (Output);
end loop;
@@ -2192,22 +2228,15 @@
Item_Id : Entity_Id;
begin
- -- A package with null initialization list is not allowed to have
- -- additional initializations.
-
- if Null_Seen then
- Error_Msg_NE ("package & has null initialization", Item, Pack_Id);
-
-- Null initialization list
- elsif Nkind (Item) = N_Null then
+ if Nkind (Item) = N_Null then
+ if Null_Seen then
+ Error_Msg_N ("multiple null initializations not allowed", Item);
- -- Catch a case where a null initialization item appears in a list
- -- of non-null items.
-
- if Non_Null_Seen then
- Error_Msg_NE
- ("package & has non-null initialization", Item, Pack_Id);
+ elsif Non_Null_Seen then
+ Error_Msg_N
+ ("cannot mix null and non-null initialization items", Item);
else
Null_Seen := True;
end if;
@@ -2217,6 +2246,11 @@
else
Non_Null_Seen := True;
+ if Null_Seen then
+ Error_Msg_N
+ ("cannot mix null and non-null initialization items", Item);
+ end if;
+
Analyze (Item);
if Is_Entity_Name (Item) then
@@ -2287,21 +2321,16 @@
Input_Id : Entity_Id;
begin
- -- An initialization item with null inputs is not allowed to have
- -- assitional inputs.
-
- if Null_Seen then
- Error_Msg_N ("item has null input list", Item);
-
-- Null input list
- elsif Nkind (Input) = N_Null then
+ if Nkind (Input) = N_Null then
+ if Null_Seen then
+ Error_Msg_N
+ ("multiple null initializations not allowed", Item);
- -- Catch a case where a null input appears in a list of non-
- -- null inpits.
-
- if Non_Null_Seen then
- Error_Msg_N ("item has non-null input list", Item);
+ elsif Non_Null_Seen then
+ Error_Msg_N
+ ("cannot mix null and non-null initialization item", Item);
else
Null_Seen := True;
end if;
@@ -2311,6 +2340,11 @@
else
Non_Null_Seen := True;
+ if Null_Seen then
+ Error_Msg_N
+ ("cannot mix null and non-null initialization item", Item);
+ end if;
+
Analyze (Input);
if Is_Entity_Name (Input) then
@@ -9299,7 +9333,7 @@
elsif Nkind (State) = N_Null then
Name := New_Internal_Name ('S');
- Is_Null := True;
+ Is_Null := True;
Null_Seen := True;
-- Catch a case where a null state appears in a list of
@@ -19946,7 +19980,7 @@
Dep_Id := Entity_Of (Dep_Input);
-- Inspect all inputs of the refinement clause and attempt
- -- to match against the inputs of the dependance clause.
+ -- to match against the inputs of the dependence clause.
Ref_Input := First (Ref_Inputs);
while Present (Ref_Input) loop
@@ -20256,7 +20290,7 @@
begin
-- The analysis of pragma Depends should produce normalized clauses
-- with exactly one output. This is important because output items
- -- are unique in the whole dependance relation and can be used as
+ -- are unique in the whole dependence relation and can be used as
-- keys.
pragma Assert (No (Next (Dep_Output)));
