[gcc r12-4175] [Ada] Fix latent bug in set_end_locus_from_node

[gcc r12-4175] [Ada] Fix latent bug in set_end_locus_from_node

[Pierre-Marie de Rodat]

https://gcc.gnu.org/g:650ad524d8a5928998037c1f6434054d46a400d4

commit r12-4175-g650ad524d8a5928998037c1f6434054d46a400d4
Author: Bob Duff <duff@adacore.com>
Date:   Wed Aug 11 07:44:31 2021 -0400

    [Ada] Fix latent bug in set_end_locus_from_node
    
    gcc/ada/
    
            * gcc-interface/trans.c (set_end_locus_from_node): Check that
            Handled_Statement_Sequence is not Empty before calling
            End_Label, because the Empty node has no End_Label, and
            depending on the exact node layout chosen by gen_il, calling
            End_Label might crash, or might work OK by accident.

Diff:
---
 gcc/ada/gcc-interface/trans.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/gcc/ada/gcc-interface/trans.c b/gcc/ada/gcc-interface/trans.c
index 158bfe35f7b..4aaa567237c 100644
--- a/gcc/ada/gcc-interface/trans.c
+++ b/gcc/ada/gcc-interface/trans.c
@@ -10507,10 +10507,15 @@ set_end_locus_from_node (tree gnu_node, Node_Id gnat_node)
     case N_Package_Body:
     case N_Subprogram_Body:
     case N_Block_Statement:
-      gnat_end_label = End_Label (Handled_Statement_Sequence (gnat_node));
+      if (Present (Handled_Statement_Sequence (gnat_node)))
+	gnat_end_label = End_Label (Handled_Statement_Sequence (gnat_node));
+      else
+	gnat_end_label = Empty;
+
       break;
 
     case N_Package_Declaration:
+      gcc_checking_assert (Present (Specification (gnat_node)));
       gnat_end_label = End_Label (Specification (gnat_node));
       break;