[multiple changes]

2014-01-24  Vincent Celier  <celier@adacore.com>

	* projects.texi: Document that aggregate projects are only
	supported by gprbuild, but not by gnatmake.  Document that the
	only attribute Switches in package Binder of aggregate projects
	will be ignored if its index is not others.  Document that
	attribute Global_Config_File is allowed in package Binder of
	aggregate projects.

2014-01-24  Robert Dewar  <dewar@adacore.com>

	* sem_prag.adb: Minor code reorganization.
	* sem_util.adb: Minor fix of potential latent bug in Is_LHS.

From-SVN: r207029

1 files changed, 33 insertions, 5 deletions

diff --git a/gcc/ada/sem_util.adb b/gcc/ada/sem_util.adb
index dc6a495..b5bb307 100644
--- a/gcc/ada/sem_util.adb
+++ b/gcc/ada/sem_util.adb
@@ -9850,20 +9850,48 @@ package body Sem_Util is
    ------------
 
    --  We seem to have a lot of overlapping functions that do similar things
-   --  (testing for left hand sides or lvalues???). Anyway, since this one is
-   --  purely syntactic, it should be in Sem_Aux I would think???
+   --  (testing for left hand sides or lvalues???).
 
    function Is_LHS (N : Node_Id) return Boolean is
       P : constant Node_Id := Parent (N);
 
    begin
+      --  Return True if we are the left hand side of an assignment statement
+
       if Nkind (P) = N_Assignment_Statement then
          return Name (P) = N;
 
-      elsif
-        Nkind_In (P, N_Indexed_Component, N_Selected_Component, N_Slice)
+      --  Case of prefix of indexed or selected component or slice
+
+      elsif Nkind_In (P, N_Indexed_Component, N_Selected_Component, N_Slice)
+        and then N = Prefix (P)
       then
-         return N = Prefix (P) and then Is_LHS (P);
+         --  Here we have the case where the parent P is N.Q or N(Q .. R).
+         --  If P is an LHS, then N is also effectively an LHS, but there
+         --  is an important exception. If N is of an access type, then
+         --  what we really have is N.all.Q (or N.all(Q .. R)). In either
+         --  case this makes N.all a left hand side but not N itself!
+
+         --  Here follows a worrisome kludge. If Etype (N) is not set, which
+         --  for sure happens in the call from Find_Direct_Name, that means we
+         --  don't know if N is of an access type, so we can't give an accurate
+         --  answer. For now, we assume we do not have an access type, which
+         --  means for example that P.Q.R := X will look like a modification
+         --  of P, even if P.Q eventually turns out to be an access type. The
+         --  consequence is at least that in some cases we incorrectly identify
+         --  a reference as a modification. It is not clear if there are any
+         --  other bad consequences. ???
+
+         if Present (Etype (N)) and then Is_Access_Type (Etype (N)) then
+            return False;
+
+         --  OK, not access type case, so just test whole expression
+
+         else
+            return Is_LHS (P);
+         end if;
+
+      --  All other cases are not left hand sides
 
       else
          return False;