[Bug middle-end/92410] Invalid access to df->insns[] in regstat_bb_compute_calls_crossed (caught by hwasan)

[matmal01 at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92410

--- Comment #7 from Matthew Malcomson <matmal01 at gcc dot gnu.org> ---
(In reply to Matthew Malcomson from comment #6)
> I'm not sure whether there's any pre-existing "should not use dataflow
> queries on notes" rule.  If there is, then the
> regstat_bb_compute_calls_crossed function should be modified to check for
> NONDEBUG_INSN_P and continue earlier on its loop.

I now see that `df_bb_refs_record` generates insn info for notes (but leaves it
mostly zeroed out).  I figure doing the same for the notes emitted by
`reemit_notes` seems reasonable.


Currently bootstrapping and regtesting (both with HWASAN and without) the
following patch.


diff --git a/gcc/haifa-sched.c b/gcc/haifa-sched.c
index 41cf1f3..2e1a84f 100644
--- a/gcc/haifa-sched.c
+++ b/gcc/haifa-sched.c
@@ -5433,6 +5433,7 @@ reemit_notes (rtx_insn *insn)

          last = emit_note_before (note_type, last);
          remove_note (insn, note);
+         df_insn_create_insn_record (last);
        }
     }
 }
diff --git a/gcc/regstat.c b/gcc/regstat.c
index 4da9b7c..c6cefb11 100644
--- a/gcc/regstat.c
+++ b/gcc/regstat.c
@@ -324,6 +324,7 @@ regstat_bb_compute_calls_crossed (unsigned int bb_index,
bitmap live)

   FOR_BB_INSNS_REVERSE (bb, insn)
     {
+      gcc_assert (INSN_UID (insn) < DF_INSN_SIZE ());
       struct df_insn_info *insn_info = DF_INSN_INFO_GET (insn);
       unsigned int regno;