If a for loop starts with "for X in F (...)'Range loop", where F is a
function returning an unconstrained array, then memory is leaked. This
patch fixes that bug.
Running these commands:
gnatmake -q -f main.adb
main
On the following sources:
with Text_IO; use Text_IO;
package P is
function Get_Objects return String;
end P;
package body P is
function Get_Objects return String is
begin
return "xyzzy";
end Get_Objects;
end P;
with Text_IO; use Text_IO;
pragma Warnings (Off, "an internal GNAT unit");
with System.Secondary_Stack;
pragma Warnings (On, "an internal GNAT unit");
with P; use P;
procedure Main is
Max_Iterations : constant Integer := 1_000;
procedure Leak_Call is
begin
for Id in Get_Objects'Range loop
null;
end loop;
end Leak_Call;
procedure SS_Info is new System.Secondary_Stack.SS_Info
(Text_IO.Put_Line);
begin
for Iteration in 1 .. Max_Iterations loop
Leak_Call;
end loop;
SS_Info;
end Main;
Should produce the following output:
Secondary Stack information:
Total size : 10240 bytes
Current allocated space : 0 bytes
Number of Chunks : 1
Default size of Chunks : 10240
Tested on x86_64-pc-linux-gnu, committed on trunk
2019-09-19 Bob Duff <d...@adacore.com>
gcc/ada/
* sem_attr.adb (Resolve_Attribute): Make sure the secondary
stack is properly managed in the case of a 'Range attribute in a
loop.--- gcc/ada/sem_attr.adb
+++ gcc/ada/sem_attr.adb
@@ -11570,6 +11570,16 @@ package body Sem_Attr is
begin
if not Is_Entity_Name (P) or else not Is_Type (Entity (P)) then
Resolve (P);
+
+ -- If the prefix is a function call returning on the secondary
+ -- stack, we must make sure to mark/release the stack.
+
+ if Nkind (P) = N_Function_Call
+ and then Nkind (Parent (N)) = N_Loop_Parameter_Specification
+ and then Requires_Transient_Scope (Etype (P))
+ then
+ Set_Uses_Sec_Stack (Scope (Current_Scope));
+ end if;
end if;
Dims := Expressions (N);
