diff options
Diffstat (limited to 'gdb/frame.c')
| -rw-r--r-- | gdb/frame.c | 75 |
1 files changed, 43 insertions, 32 deletions
diff --git a/gdb/frame.c b/gdb/frame.c index c233193a00a..8609ce194fb 100644 --- a/gdb/frame.c +++ b/gdb/frame.c @@ -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; - } - - /* 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 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. + + 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 |