[committed] Fix error: Unknown DWARF DW_FORM_ref_sig8

[Tom de Vries <tdevries@suse.de>]

Hi,

When running the gdb testsuite using target board cc-with-dwz, I ran into:
...
dwz: cpexprs-debug-types: Unknown DWARF DW_FORM_ref_sig8
dwz: cpexprs-debug-types: Couldn't read abbrev at offset 0x64
...

I traced this back to some code in read_abbrev, which until recent was:
...
         if (form == 2
             || (form > DW_FORM_flag_present && form != DW_FORM_ref_sig8))
           {
             error (0, 0, "%s: Unknown DWARF %s",
                    dso->filename, get_DW_FORM_str (form));
...
but now has been extended to:
...
         if (form == 2
             || (form > DW_FORM_flag_present
                 && (form != DW_FORM_ref_sig8
                     || form != DW_FORM_data16
                     || form != DW_FORM_line_strp)))
...

Before, form == DW_FORM_ref_sig8 didn't trigger an error because
form != DW_FORM_ref_sig8 evaluated to false.

Now, form == DW_FORM_ref_sig8 does trigger an error because
form != DW_FORM_data16 evaluates to true.

Fix by using this instead:
...
                 && !(form == DW_FORM_ref_sig8
                      || form == DW_FORM_data16
                      || form == DW_FORM_line_strp)))
...

Tested dwz testsuite, and cpexprs-debug-types.

Committed to trunk.

Thanks,
- Tom

Fix error: Unknown DWARF DW_FORM_ref_sig8

2020-10-02  Tom de Vries  <tdevries@suse.de>

	* dwz.c (read_abbrev): Fix "Unknown DWARF DW_FORM_ref_sig8" error.

---
 dwz.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/dwz.c b/dwz.c
index eb52079..487fbc6 100644
--- a/dwz.c
+++ b/dwz.c
@@ -1261,9 +1261,9 @@ read_abbrev (DSO *dso, unsigned char *ptr)
 	  form = read_uleb128 (p);
 	  if (form == 2
 	      || (form > DW_FORM_flag_present
-		  && (form != DW_FORM_ref_sig8
-		      || form != DW_FORM_data16
-		      || form != DW_FORM_line_strp)))
+		  && !(form == DW_FORM_ref_sig8
+		       || form == DW_FORM_data16
+		       || form == DW_FORM_line_strp)))
 	    {
 	      error (0, 0, "%s: Unknown DWARF %s",
 		     dso->filename, get_DW_FORM_str (form));