[COMMITTED] ada: Add missing ss_mark/ss_release in quantified expressions

["Marc Poulhiès" <poulhies@adacore.com>]

From: Bob Duff <duff@adacore.com>

If a quantified expression says "for all ... of F(...)"
where F(...) is a function call that returns on the secondary
stack, we need to clean up the secondary stack. This patch
adds the required ss_mark/ss_release in that case.

gcc/ada/

	* exp_ch4.adb
	(Expand_N_Quantified_Expression): Detect the secondary-stack
	case, and find the innermost scope where we should mark/release,
	and Set_Uses_Sec_Stack on that. Skip intermediate blocks and loops
	that are part of expansion.

Tested on x86_64-pc-linux-gnu, committed on master.

---
 gcc/ada/exp_ch4.adb | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/gcc/ada/exp_ch4.adb b/gcc/ada/exp_ch4.adb
index fdaeb50512f..7b6e997e3e7 100644
--- a/gcc/ada/exp_ch4.adb
+++ b/gcc/ada/exp_ch4.adb
@@ -11116,6 +11116,32 @@ package body Exp_Ch4 is
          Freeze_Before (P, Etype (Var));
       end;
 
+      --  For an expression of the form "for all/some X of F(...) => ...",
+      --  where F(...) is a function call that returns on the secondary stack,
+      --  we need to mark an enclosing scope as Uses_Sec_Stack. We must do
+      --  this before expansion, which can obscure the tree. Note that we
+      --  might be inside another quantified expression. Skip blocks and
+      --  loops that were generated by expansion.
+
+      if Present (Iterator_Specification (N))
+        and then Nkind (Name (Iterator_Specification (N))) = N_Function_Call
+        and then Needs_Secondary_Stack
+                   (Etype (Name (Iterator_Specification (N))))
+      then
+         declare
+            Source_Scope : Entity_Id := Current_Scope;
+         begin
+            while Ekind (Source_Scope) in E_Block | E_Loop
+              and then not Comes_From_Source (Source_Scope)
+            loop
+               Source_Scope := Scope (Source_Scope);
+            end loop;
+
+            Set_Uses_Sec_Stack (Source_Scope);
+            Check_Restriction (No_Secondary_Stack, N);
+         end;
+      end if;
+
       --  Create the declaration of the flag which tracks the status of the
       --  quantified expression. Generate:
 
-- 
2.40.0