Re: Bug in i386_process_record?

[Michael Snyder <msnyder@vmware.com>]

Hui Zhu wrote:
> On Sun, Aug 23, 2009 at 11:07, Michael Snyder<msnyder@vmware.com> wrote:
>> Hi, please *don't* check this in -- I found a problem with it.
>>
>> Try running it with "set debug record 1" during the recording pass.
>>
>> I see a whole lot of these:
>>
>> Process record ignores the memory change of instruction at address
>> 0x0x587be9 because it can't get the value of the segment register.
> 
> 
> Hi Michael,
> 
> Most of the string ops instruction will use segment register.
> But I check the some linux program that have string ops insn.  I found
> that in linux (maybe glibc), the value of the segment register is 0,
> so it will not affect anything.

Hmm, ok, but this is i386-tdep.c, not i386-linux-tdep.c...

> And in linux user level, looks we don't have any good way to get the
> value of the segment register.
> 
> So I think this patch is OK.

I see -- so, we don't really "ignore" the memory change at all.

Isn't the message misleading, then?

What about something like:

@@ -4458,11 +4458,12 @@ reswitch:
            if (ir.aflag)
              {
                /* addr += ((uint32_t) read_register (I386_ES_REGNUM)) 
<< 4; */
-              if (record_debug)
-                printf_unfiltered (_("Process record ignores the memory 
change "
-                                     "of instruction at address 0x%s 
because "
-                                     "it can't get the value of the 
segment "
-                                     "register.\n"),
+              if (record_debug &&
+                 read_register (I386_ES_REGNUM) != 0)
+                printf_unfiltered (_("Process record ignores value of ES "
+                                     "register for instruction at 
address %s "
+                                     "because "it can't get the value of "
+                                     "the segment register.\n"),
                                     paddress (gdbarch, ir.addr));
              }
            if (prefixes & (PREFIX_REPZ | PREFIX_REPNZ))