sem_ch5.adb, [...]: Update handling of assigned value/unreferenced warnings

2007-12-06  Robert Dewar  <dewar@adacore.com>

	* sem_ch5.adb, s-taskin.adb, a-ciorma.adb, a-coorma.adb, a-cohama.adb, 
	a-cihama.adb, g-awk.adb, 
	s-inmaop-posix.adb: Update handling of assigned value/unreferenced
	warnings

	* exp_smem.adb: Update handling of assigned value/unreferenced warnings

	* sem.adb: Update handling of assigned value/unreferenced warnings

	* a-exexpr-gcc.adb: Add a pragma warnings off for boolean return

	* lib-xref.ads: Improve documentation for k xref type

	* lib-xref.adb: 
	Update handling of assigned value/unreferenced warnings
	(Generate_Reference): Warning for reference to entity for which a
	pragma Unreferenced has been given should be unconditional.
	If the entity is a discriminal, mark the original
	discriminant as referenced.

	* sem_warn.ads, sem_warn.adb
	(Check_One_Unit): Test Renamed_In_Spec to control giving warning for
	no entities referenced in package
	(Check_One_Unit): Don't give message about no entities referenced in
	a package if a pragma Unreferenced has appeared.
	Handle new warning flag -gnatw.a/-gnatw.A
	Update handling of assigned value/unreferenced warnings

	* atree.h: Add flags up to Flag247
	(Flag231): New macro.

From-SVN: r130815

1 files changed, 32 insertions, 7 deletions

diff --git a/gcc/ada/lib-xref.ads b/gcc/ada/lib-xref.ads
index 1a96e81..4d23773 100644
--- a/gcc/ada/lib-xref.ads
+++ b/gcc/ada/lib-xref.ads
@@ -237,8 +237,33 @@ package Lib.Xref is
    --           source node that generates the implicit reference, and it is
    --           useful to record this one.
 
-   --           k is used to denote a reference to the parent unit, in the
-   --           cross-reference line for a child unit.
+   --           k is another non-standard reference type, used to record a
+   --           reference from a child unit to its parent. For various cross-
+   --           referencing tools, we need a pointer from the xref entries for
+   --           the child to the parent. This is the opposite way round from
+   --           normal xref entries, since the reference is *from* the child
+   --           unit *to* the parent unit, yet appears in the xref entries for
+   --           the child. Consider this example:
+   --
+   --             package q is
+   --             end;
+   --             package q.r is
+   --             end q.r;
+   --
+   --           The ali file for q-r.ads has these entries
+   --
+   --             D q.ads
+   --             D q-r.ads
+   --             D system.ads
+   --             X 1 q.ads
+   --             1K9*q 2e4 2|1r9 2r5
+   --             X 2 q-r.ads
+   --             1K11*r 1|1k9 2|2l7 2e8
+   --
+   --           Here the 2|1r9 entry appearing in the section for the parent
+   --           is the normal reference from the child to the parent. The 1k9
+   --           entry in the section for the child duplicates this information
+   --           but appears in the child rather than the parent.
 
    --           l is used to identify the occurrence in the source of the
    --           name on an end line. This is just a syntactic reference
@@ -568,11 +593,11 @@ package Lib.Xref is
    --  a renaming of a predefined operator.
 
    procedure Generate_Reference
-     (E             : Entity_Id;
-      N             : Node_Id;
-      Typ           : Character := 'r';
-      Set_Ref       : Boolean   := True;
-      Force         : Boolean   := False);
+     (E       : Entity_Id;
+      N       : Node_Id;
+      Typ     : Character := 'r';
+      Set_Ref : Boolean   := True;
+      Force   : Boolean   := False);
    --  This procedure is called to record a reference. N is the location
    --  of the reference and E is the referenced entity. Typ is one of:
    --