This patch does not affect the behavior of native compilers. It
extends the cases in which aggregates are internally converted
into purely positional form, which helps the backend of VM
compilers.
Tested on x86_64-pc-linux-gnu, committed on trunk
2011-08-03 Javier Miranda <mira...@adacore.com>
* exp_aggr.adb (Flatten): Convert to positional form aggregates whose
low bound is not known at compile time but they have no others choice.
Done because in this case the bounds can be obtained directly from the
aggregate.
Index: exp_aggr.adb
===================================================================
--- exp_aggr.adb (revision 177240)
+++ exp_aggr.adb (working copy)
@@ -3825,6 +3825,8 @@
Lov : Uint;
Hiv : Uint;
+ Others_Present : Boolean := False;
+
begin
if Nkind (Original_Node (N)) = N_String_Literal then
return True;
@@ -3839,8 +3841,44 @@
Lov := Expr_Value (Lo);
Hiv := Expr_Value (Hi);
+ -- Check if there is an others choice
+
+ if Present (Component_Associations (N)) then
+ declare
+ Assoc : Node_Id;
+ Choice : Node_Id;
+
+ begin
+ Assoc := First (Component_Associations (N));
+ while Present (Assoc) loop
+ Choice := First (Choices (Assoc));
+
+ while Present (Choice) loop
+ if Nkind (Choice) = N_Others_Choice then
+ Others_Present := True;
+ end if;
+
+ Next (Choice);
+ end loop;
+
+ Next (Assoc);
+ end loop;
+ end;
+ end if;
+
+ -- If the low bound is not known at compile time and others is not
+ -- present we can proceed since the bounds can be obtained from the
+ -- aggregate.
+
+ -- Note: This case is required in VM platforms since their backends
+ -- normalize array indexes in the range 0 .. N-1. Hence, if we do
+ -- not flat an array whose bounds cannot be obtained from the type
+ -- of the index the backend has no way to properly generate the code.
+ -- See ACATS c460010 for an example.
+
if Hiv < Lov
- or else not Compile_Time_Known_Value (Blo)
+ or else (not Compile_Time_Known_Value (Blo)
+ and then Others_Present)
then
return False;
end if;
