Re: PR27723, Internal error in select_cie_for_fde

Let's make sure what we allow in the CIE initial instructions and what
select_cie_for_fde compares for a match is always in sync.  Also
correct the previous patch that allowed DW_CFA_GNU_window_save to be
part of the CIE initial instructions, which was likely a mistake.

	PR 27723
	* dw2gencfi.c (initial_cie_insn): New function, extracted from..
	(select_cie_for_fde): ..here.  Simplify.

diff --git a/gas/ChangeLog b/gas/ChangeLog
index 07e5581119adce843e9c9ec98c9823523832893f..10127ccb03b331c103fb6f3280f86431d5ccffba 100644 (file)
--- a/gas/ChangeLog
+++ b/gas/ChangeLog
@@ -1,3 +1,9 @@
+2021-04-14  Alan Modra  <amodra@gmail.com>
+
+       PR 27723
+       * dw2gencfi.c (initial_cie_insn): New function, extracted from..
+       (select_cie_for_fde): ..here.  Simplify.
+
 2021-04-14  Alan Modra  <amodra@gmail.com>
 
        PR 27723

diff --git a/gas/dw2gencfi.c b/gas/dw2gencfi.c
index ffaef52cd596be4b1f9aa6ca6d58c071251a6153..c06561460326fbe39cfcc3087dd90e17c33031ad 100644 (file)
--- a/gas/dw2gencfi.c
+++ b/gas/dw2gencfi.c
@@ -2043,6 +2043,63 @@ output_fde (struct fde_entry *fde, struct cie_entry *cie,
   symbol_set_value_now (end_address);
 }
 
+/* Allow these insns to be put in the initial sequence of a CIE.
+   If J is non-NULL, then compare I and J insns for a match.  */
+
+static inline bool
+initial_cie_insn (const struct cfi_insn_data *i, const struct cfi_insn_data *j)
+{
+  if (j && i->insn != j->insn)
+    return false;
+  switch (i->insn)
+    {
+    case DW_CFA_offset:
+    case DW_CFA_def_cfa:
+    case DW_CFA_val_offset:
+      if (j)
+       {
+         if (i->u.ri.reg != j->u.ri.reg)
+           return false;
+         if (i->u.ri.offset != j->u.ri.offset)
+           return false;
+       }
+      break;
+
+    case DW_CFA_register:
+      if (j)
+       {
+         if (i->u.rr.reg1 != j->u.rr.reg1)
+           return false;
+         if (i->u.rr.reg2 != j->u.rr.reg2)
+           return false;
+       }
+      break;
+
+    case DW_CFA_def_cfa_register:
+    case DW_CFA_restore:
+    case DW_CFA_undefined:
+    case DW_CFA_same_value:
+      if (j)
+       {
+         if (i->u.r != j->u.r)
+           return false;
+       }
+      break;
+
+    case DW_CFA_def_cfa_offset:
+      if (j)
+       {
+         if (i->u.i != j->u.i)
+           return false;
+       }
+      break;
+
+    default:
+      return false;
+    }
+  return true;
+}
+
 static struct cie_entry *
 select_cie_for_fde (struct fde_entry *fde, bool eh_frame,
                    struct cfi_insn_data **pfirst, int align)
@@ -2088,75 +2145,15 @@ select_cie_for_fde (struct fde_entry *fde, bool eh_frame,
           i != cie->last && j != NULL;
           i = i->next, j = j->next)
        {
-         if (i->insn != j->insn)
-           goto fail;
-         switch (i->insn)
-           {
-           case DW_CFA_advance_loc:
-           case DW_CFA_remember_state:
-             /* We reached the first advance/remember in the FDE,
-                but did not reach the end of the CIE list.  */
-             goto fail;
-
-           case DW_CFA_offset:
-           case DW_CFA_def_cfa:
-           case DW_CFA_val_offset:
-             if (i->u.ri.reg != j->u.ri.reg)
-               goto fail;
-             if (i->u.ri.offset != j->u.ri.offset)
-               goto fail;
-             break;
-
-           case DW_CFA_register:
-             if (i->u.rr.reg1 != j->u.rr.reg1)
-               goto fail;
-             if (i->u.rr.reg2 != j->u.rr.reg2)
-               goto fail;
-             break;
-
-           case DW_CFA_def_cfa_register:
-           case DW_CFA_restore:
-           case DW_CFA_undefined:
-           case DW_CFA_same_value:
-             if (i->u.r != j->u.r)
-               goto fail;
-             break;
-
-           case DW_CFA_def_cfa_offset:
-             if (i->u.i != j->u.i)
-               goto fail;
-             break;
-
-           case CFI_escape:
-           case CFI_val_encoded_addr:
-           case CFI_label:
-           case DW_CFA_restore_state:
-           case DW_CFA_GNU_window_save:
-             /* Don't bother matching these for now.  */
-             goto fail;
-
-           default:
-             abort ();
-           }
+         if (!initial_cie_insn (i, j))
+           break;
        }
 
-      /* Success if we reached the end of the CIE list, and we've either
-        run out of FDE entries or we've encountered an advance,
-        remember, or escape.  */
-      if (i == cie->last
-         && (!j
-             || j->insn == DW_CFA_advance_loc
-             || j->insn == DW_CFA_remember_state
-             || j->insn == DW_CFA_GNU_window_save
-             || j->insn == CFI_escape
-             || j->insn == CFI_val_encoded_addr
-             || j->insn == CFI_label))
+      if (i == cie->last)
        {
          *pfirst = j;
          return cie;
        }
-
-    fail:;
     }
 
   cie = XNEW (struct cie_entry);
@@ -2174,11 +2171,7 @@ select_cie_for_fde (struct fde_entry *fde, bool eh_frame,
 #endif
 
   for (i = cie->first; i ; i = i->next)
-    if (i->insn == DW_CFA_advance_loc
-       || i->insn == DW_CFA_remember_state
-       || i->insn == CFI_escape
-       || i->insn == CFI_val_encoded_addr
-       || i->insn == CFI_label)
+    if (!initial_cie_insn (i, NULL))
       break;
 
   cie->last = i;