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2003-03-25 Andrew Cagney <cagney@redhat.com>

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* frame.c (get_prev_frame): Delay validating a frame's ID -
	non-NULL, didn't go backwards - until an attempt to unwind it to
	the previous frame.
This commit is contained in:
Andrew Cagney 2003-03-26 00:00:07 +00:00
parent 6850776429
commit 270c3b1dfa
2 changed files with 48 additions and 31 deletions
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6
gdb/ChangeLog
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@ -1,3 +1,9 @@
2003-03-25 Andrew Cagney <cagney@redhat.com>
* frame.c (get_prev_frame): Delay validating a frame's ID -
non-NULL, didn't go backwards - until an attempt to unwind it to
the previous frame.
2003-03-25 Andrew Cagney <cagney@redhat.com>
* gdbarch.sh (DEPRECATED_EXTRA_STACK_ALIGNMENT_NEEDED): Replace

73
gdb/frame.c
View file

@ -1467,6 +1467,38 @@ get_prev_frame (struct frame_info *this_frame)
return prev_frame;
}
/* Check that this frame's ID was valid. If it wasn't, don't try to
unwind to the prev frame. Be careful to not apply this test to
the sentinel frame. */
if (this_frame->level >= 0 && !frame_id_p (get_frame_id (this_frame)))
{
if (frame_debug)
fprintf_filtered (gdb_stdlog,
"Outermost frame - this ID is NULL\n");
return NULL;
}
/* Check that this frame's ID isn't inner to (younger, below, next)
the next frame. This happens when frame unwind goes backwards.
Since the sentinel frame isn't valid, don't apply this if this
frame is entier the inner-most or sentinel frame. */
if (this_frame->level > 0
&& frame_id_inner (get_frame_id (this_frame),
get_frame_id (this_frame->next)))
error ("This frame inner-to next frame (corrupt stack?)");
/* Check that this and the next frame are different. If they are
not, there is most likely a stack cycle. As with the inner-than
test, avoid the inner-most and sentinel frames. */
/* FIXME: cagney/2003-03-17: Can't yet enable this this check. The
frame_id_eq() method doesn't yet use function addresses when
comparing frame IDs. */
if (0
&& this_frame->level > 0
&& frame_id_eq (get_frame_id (this_frame),
get_frame_id (this_frame->next)))
error ("This frame identical to next frame (corrupt stack?)");
/* Allocate the new frame but do not wire it in to the frame chain.
Some (bad) code in INIT_FRAME_EXTRA_INFO tries to look along
frame->next to pull some fancy tricks (of course such code is, by
@ -1533,38 +1565,17 @@ get_prev_frame (struct frame_info *this_frame)
&prev_frame->prologue_cache,
&prev_frame->id);
/* Check that the unwound ID is valid. */
if (!frame_id_p (prev_frame->id))
{
if (frame_debug)
fprintf_unfiltered (gdb_stdlog,
"Outermost frame - unwound frame ID invalid\n");
return NULL;
}
/* The unwound frame ID is validate at the start of this function,
as part of the logic to decide if that frame should be further
unwound, and not here while the prev frame is being created.
Doing this makes it possible for the user to examine a frame that
has an invalid frame ID.
/* Check that the new frame isn't inner to (younger, below, next)
the old frame. If that happens the frame unwind is going
backwards. */
/* FIXME: cagney/2003-02-25: Ignore the sentinel frame since that
doesn't have a valid frame ID. Should instead set the sentinel
frame's frame ID to a true `sentinel'. Leave it until after the
switch to storing the frame ID, instead of the frame base, in the
frame object. */
if (this_frame->level >= 0
&& frame_id_inner (prev_frame->id, get_frame_id (this_frame)))
error ("Unwound frame inner-to selected frame (corrupt stack?)");
/* FIXME: cagney/2003-03-14: Should check that this and next frame's
IDs are different (i.e., !frame_id_eq()). Can't yet do that as
the EQ function doesn't yet compare PC values. */
/* FIXME: cagney/2003-03-14: Should delay the evaluation of the
frame ID until when it is needed. That way the inner most frame
can be created without needing to do prologue analysis. */
/* Note that, due to frameless functions, the stronger test of the
new frame being outer to the old frame can't be used - frameless
functions differ by only their PC value. */
The very old VAX frame_args_address_correct() method noted: [...]
For the sake of argument, suppose that the stack is somewhat
trashed (which is one reason that "info frame" exists). So,
return 0 (indicating we don't know the address of the arglist) if
we don't know what frame this frame calls. */
/* FIXME: cagney/2002-12-18: Instead of this hack, should only store
the frame ID in PREV_FRAME. Unfortunatly, some architectures