frontend.adb (Frontend): Capture restrictions from config files

2011-11-21  Robert Dewar  <dewar@adacore.com>

	* frontend.adb (Frontend): Capture restrictions from config files
	* lib-load.adb (Load_Unit): Save/set/restore restriction pragma
	information
	* lib-xref.adb (Generate_Reference): Fix handling of obsolescent
	references. This was noticed during debugging, but it is not
	known if it causes real bugs.
	* restrict.ads, restrict.adb: New routines to save/set/restore
	non-partition-wide restrictions.
	* s-rident.ads: Comment changes for new handling of
	No_Elaboration_Code
	* sem.adb (Sem): Save/Set/Restore non-partition-wide restrictions
	* sem_ch10.adb (Analyze_Compilation_Unit): Remove incomplete
	attempt to save/restore non-partition-wide restrictions (now
	this work is all done in Sem).
	* sem_prag.adb (Process_Restrictions_Or_Restriction_Warnings):
	Special handling for restriction No_Elaboration_Code.

2011-11-21  Robert Dewar  <dewar@adacore.com>

	* gnat_ugn.texi: Document new handling of restrictions pragmas.

From-SVN: r181566

1 files changed, 56 insertions, 19 deletions

diff --git a/gcc/ada/restrict.adb b/gcc/ada/restrict.adb
index 399547c..df2ec7a 100644
--- a/gcc/ada/restrict.adb
+++ b/gcc/ada/restrict.adb
@@ -41,6 +41,9 @@ with Uname;    use Uname;
 
 package body Restrict is
 
+   Config_Cunit_Boolean_Restrictions : Save_Cunit_Boolean_Restrictions;
+   --  Save compilation unit restrictions set by config pragma files
+
    Restricted_Profile_Result : Boolean := False;
    --  This switch memoizes the result of Restricted_Profile function calls for
    --  improved efficiency. Valid only if Restricted_Profile_Cached is True.
@@ -100,6 +103,17 @@ package body Restrict is
       end if;
    end Abort_Allowed;
 
+   ----------------------------------------
+   -- Add_To_Config_Boolean_Restrictions --
+   ----------------------------------------
+
+   procedure Add_To_Config_Boolean_Restrictions (R : Restriction_Id) is
+   begin
+      Config_Cunit_Boolean_Restrictions (R) := True;
+   end Add_To_Config_Boolean_Restrictions;
+   --  Add specified restriction to stored configuration boolean restrictions.
+   --  This is used for handling the special case of No_Elaboration_Code.
+
    -------------------------
    -- Check_Compiler_Unit --
    -------------------------
@@ -498,7 +512,9 @@ package body Restrict is
 
       Update_Restrictions (Restrictions);
 
-      --  If in main extended unit, update main restrictions as well
+      --  If in main extended unit, update main restrictions as well. Note
+      --  that as usual we check for Main_Unit explicitly to deal with the
+      --  case of configuration pragma files.
 
       if Current_Sem_Unit = Main_Unit
         or else In_Extended_Main_Source_Unit (N)
@@ -642,6 +658,16 @@ package body Restrict is
       for J in Cunit_Boolean_Restrictions loop
          Restrictions.Set (J) := R (J);
       end loop;
+
+      --  If No_Elaboration_Code set in configuration restrictions, and we
+      --  in the main extended source, then set it here now. This is part of
+      --  the special processing for No_Elaboration_Code.
+
+      if In_Extended_Main_Source_Unit (Cunit_Entity (Current_Sem_Unit))
+        and then Config_Cunit_Boolean_Restrictions (No_Elaboration_Code)
+      then
+         Restrictions.Set (No_Elaboration_Code) := True;
+      end if;
    end Cunit_Boolean_Restrictions_Restore;
 
    -------------------------------------
@@ -656,7 +682,6 @@ package body Restrict is
    begin
       for J in Cunit_Boolean_Restrictions loop
          R (J) := Restrictions.Set (J);
-         Restrictions.Set (J) := False;
       end loop;
 
       return R;
@@ -772,6 +797,26 @@ package body Restrict is
       return New_Name;
    end Process_Restriction_Synonyms;
 
+   --------------------------------------
+   -- Reset_Cunit_Boolean_Restrictions --
+   --------------------------------------
+
+   procedure Reset_Cunit_Boolean_Restrictions is
+   begin
+      for J in Cunit_Boolean_Restrictions loop
+         Restrictions.Set (J) := False;
+      end loop;
+   end Reset_Cunit_Boolean_Restrictions;
+
+   -----------------------------------------------
+   -- Restore_Config_Cunit_Boolean_Restrictions --
+   -----------------------------------------------
+
+   procedure Restore_Config_Cunit_Boolean_Restrictions is
+   begin
+      Cunit_Boolean_Restrictions_Restore (Config_Cunit_Boolean_Restrictions);
+   end Restore_Config_Cunit_Boolean_Restrictions;
+
    ------------------------
    -- Restricted_Profile --
    ------------------------
@@ -1004,6 +1049,15 @@ package body Restrict is
       end if;
    end Same_Unit;
 
+   --------------------------------------------
+   -- Save_Config_Cunit_Boolean_Restrictions --
+   --------------------------------------------
+
+   procedure Save_Config_Cunit_Boolean_Restrictions is
+   begin
+      Config_Cunit_Boolean_Restrictions := Cunit_Boolean_Restrictions_Save;
+   end Save_Config_Cunit_Boolean_Restrictions;
+
    ------------------------------
    -- Set_Hidden_Part_In_SPARK --
    ------------------------------
@@ -1070,23 +1124,6 @@ package body Restrict is
       N : Node_Id)
    is
    begin
-      --  Restriction No_Elaboration_Code must be enforced on a unit by unit
-      --  basis. Hence, we avoid setting the restriction when processing an
-      --  unit which is not the main one being compiled (or its corresponding
-      --  spec). It can happen, for example, when processing an inlined body
-      --  (the package containing the inlined subprogram is analyzed,
-      --  including its pragma Restrictions).
-
-      --  This seems like a very nasty kludge??? This is not the only per unit
-      --  restriction why is this treated specially ???
-
-      if R = No_Elaboration_Code
-        and then Current_Sem_Unit /= Main_Unit
-        and then Cunit (Current_Sem_Unit) /= Library_Unit (Cunit (Main_Unit))
-      then
-         return;
-      end if;
-
       Restrictions.Set (R) := True;
 
       if Restricted_Profile_Cached and Restricted_Profile_Result then