This implements a new configuration pragma Ignore_Pragma (IDENTIFIER)
which causes any subsequent occurrences of pragma IDENTIFIER (...) to
be completely ignored. The following test program compiles as shown:
1. procedure IgnorePR is
2. begin
3. pragma Ignore_Pragma;
|
>>> wrong number of arguments for pragma "Ignore_Pragma"
4. pragma Ignore_Pragma ("abc");
|
>>> incorrect argument for pragma "Ignore_Pragma"
5. pragma Ignore_Pragma (Import);
6. pragma Import (RUBBISH);
7. end;
Here lines 3 and 4 have invalid uses of the pragma, properly
flagged, but the junk pragma Import on line 6 is ignored
because of the correctly used Ignore_Pragma on line 5.
Tested on x86_64-pc-linux-gnu, committed on trunk
2015-05-12 Robert Dewar <[email protected]>
* exp_prag.adb (Expand_N_Pragma): Rewrite ignored pragma as
Null statements.
* namet.ads (Boolean3): Document this flag used for Ignore_Pragma.
* par-prag.adb (Prag): Implement Ignore_Pragma.
* sem_prag.adb: Implement Ignore_Pragma.
* snames.ads-tmpl: Add entries for pragma Ignore_Pragma.
Index: exp_prag.adb
===================================================================
--- exp_prag.adb (revision 223033)
+++ exp_prag.adb (working copy)
@@ -843,6 +843,15 @@
Pname : constant Name_Id := Pragma_Name (N);
begin
+ -- Rewrite pragma ignored by Ignore_Pragma to null statement, so that/
+ -- back end or the expander here does not get over-enthusiastic and
+ -- start processing such a pragma!
+
+ if Get_Name_Table_Boolean3 (Pname) then
+ Rewrite (N, Make_Null_Statement (Sloc (N)));
+ return;
+ end if;
+
-- Note: we may have a pragma whose Pragma_Identifier field is not a
-- recognized pragma, and we must ignore it at this stage.
Index: sem_prag.adb
===================================================================
--- sem_prag.adb (revision 223033)
+++ sem_prag.adb (working copy)
@@ -9373,6 +9373,12 @@
return;
end if;
+ -- Ignore pragma if Ignore_Pragma applies
+
+ if Get_Name_Table_Boolean3 (Pname) then
+ return;
+ end if;
+
-- Here to start processing for recognized pragma
Prag_Id := Get_Pragma_Id (Pname);
@@ -14239,6 +14245,17 @@
end;
end Ident;
+ -------------------
+ -- Ignore_Pragma --
+ -------------------
+
+ -- pragma Ignore_Pragma (pragma_IDENTIFIER);
+
+ -- Entirely handled in the parser, nothing to do here
+
+ when Pragma_Ignore_Pragma =>
+ null;
+
----------------------------
-- Implementation_Defined --
----------------------------
@@ -25690,6 +25707,7 @@
Pragma_Ghost => 0,
Pragma_Global => -1,
Pragma_Ident => -1,
+ Pragma_Ignore_Pragma => 0,
Pragma_Implementation_Defined => -1,
Pragma_Implemented => -1,
Pragma_Implicit_Packing => 0,
Index: par-prag.adb
===================================================================
--- par-prag.adb (revision 223033)
+++ par-prag.adb (working copy)
@@ -290,6 +290,12 @@
return Pragma_Node;
end if;
+ -- Ignore pragma previously flagged by Ignore_Pragma
+
+ if Get_Name_Table_Boolean3 (Prag_Name) then
+ return Pragma_Node;
+ end if;
+
-- Count number of arguments. This loop also checks if any of the arguments
-- are Error, indicating a syntax error as they were parsed. If so, we
-- simply return, because we get into trouble with cascaded errors if we
@@ -425,6 +431,28 @@
Ada_Version := Ada_Version_Explicit;
end if;
+ -------------------
+ -- Ignore_Pragma --
+ -------------------
+
+ -- Processing for this pragma must be done at parse time, since we want
+ -- be able to ignore pragmas that are otherwise processed at parse time.
+
+ when Pragma_Ignore_Pragma => Ignore_Pragma : declare
+ A : Node_Id;
+
+ begin
+ Check_Arg_Count (1);
+ Check_No_Identifier (Arg1);
+ A := Expression (Arg1);
+
+ if Nkind (A) /= N_Identifier then
+ Error_Msg ("incorrect argument for pragma %", Sloc (A));
+ else
+ Set_Name_Table_Boolean3 (Chars (A), True);
+ end if;
+ end Ignore_Pragma;
+
----------------
-- List (2.8) --
----------------
Index: namet.ads
===================================================================
--- namet.ads (revision 223033)
+++ namet.ads (working copy)
@@ -135,7 +135,8 @@
-- Restriction[_Warning]s pragmas for No_Use_Of_Entity. This avoids most
-- unnecessary searches of the No_Use_Of_Entity table.
--- The Boolean3 field is not used
+-- The Boolean3 field is set for names of pragmas that are to be ignored
+-- because of the occurrence of a corresponding pragma Ignore_Pragma.
-- In the binder, we have the following uses:
Index: snames.ads-tmpl
===================================================================
--- snames.ads-tmpl (revision 223033)
+++ snames.ads-tmpl (working copy)
@@ -401,6 +401,7 @@
-- Fast_Math.
Name_Favor_Top_Level : constant Name_Id := N + $; -- GNAT
+ Name_Ignore_Pragma : constant Name_Id := N + $; -- GNAT
Name_Implicit_Packing : constant Name_Id := N + $; -- GNAT
Name_Initialize_Scalars : constant Name_Id := N + $; -- GNAT
Name_Interrupt_State : constant Name_Id := N + $; -- GNAT
@@ -1749,6 +1750,7 @@
Pragma_Extensions_Allowed,
Pragma_External_Name_Casing,
Pragma_Favor_Top_Level,
+ Pragma_Ignore_Pragma,
Pragma_Implicit_Packing,
Pragma_Initialize_Scalars,
Pragma_Interrupt_State,
