Fix finish command for PNaCl.

gdb/frame.c

 /* Cache and manage frames for GDB, the GNU debugger.
 
    Copyright (C) 1986-1987, 1989, 1991, 1994-1996, 1998, 2000-2004,
    2007-2012 Free Software Foundation, Inc.
 
    This file is part of GDB.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 3 of the License, or
@@ skipping 430 matching lines @@
   if (!frame_id_p (l))
     return 0;
 
   return (l.inline_depth != 0);
 }
 
 int
 frame_id_eq (struct frame_id l, struct frame_id r)
 {
   int eq;
+  uint32_t max_addr = (uint32_t) -1;

[eaeltsin, 2013/08/06 18:14:42]

const or #define?

if you use this for &, then either provide a synonym like 'addr_mask', or use %
instead.

[halyavin, 2013/08/07 08:04:25]

I used conversion instead of &.

 
   if (!l.stack_addr_p && l.special_addr_p
       && !r.stack_addr_p && r.special_addr_p)
     /* The outermost frame marker is equal to itself.  This is the
        dodgy thing about outer_frame_id, since between execution steps
        we might step into another function - from which we can't
        unwind either.  More thought required to get rid of
        outer_frame_id.  */
     eq = 1;
   else if (!l.stack_addr_p || !r.stack_addr_p)
     /* Like a NaN, if either ID is invalid, the result is false.
        Note that a frame ID is invalid iff it is the null frame ID.  */
     eq = 0;
-  else if (l.stack_addr != r.stack_addr)
+  else if ((l.stack_addr != r.stack_addr && l.stack_addr > max_addr
+           && r.stack_addr > max_addr)
+           || (l.stack_addr & max_addr) != (r.stack_addr & max_addr))

[eaeltsin, 2013/08/06 18:14:42]

This definitely needs a comment, explaining what this does and also marking this
as a temporary, non-upstreamable thing.

What is the origin of l.stack_addr and r.stack_addr. If these are both extracted
from stack, then both should probably be 32-bit or 64-bit simultaneously? How
rbp value gets into these variables?

BTW, seems the following works OK in both modes:
  (l.stack_addr & ADDR_MASK == r.stack_addr & ADDR_MASK)

[halyavin, 2013/08/07 08:04:25]

One value is read from the stack, the other is read from the register.
Yes, but it increase false positives for normal 64-bit mode.

     /* If .stack addresses are different, the frames are different.  */
     eq = 0;
   else if (l.code_addr_p && r.code_addr_p && l.code_addr != r.code_addr)
     /* An invalid code addr is a wild card.  If .code addresses are
        different, the frames are different.  */
     eq = 0;
   else if (l.special_addr_p && r.special_addr_p
            && l.special_addr != r.special_addr)
     /* An invalid special addr is a wild card (or unused).  Otherwise
        if special addresses are different, the frames are different.  */
@@ skipping 2032 matching lines @@
 
   /* Debug this files internals.  */
   add_setshow_zinteger_cmd ("frame", class_maintenance, &frame_debug,  _("\
 Set frame debugging."), _("\
 Show frame debugging."), _("\
 When non-zero, frame specific internal debugging is enabled."),
                             NULL,
                             show_frame_debug,
                             &setdebuglist, &showdebuglist);
 }