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Revert "Make use of the frame stash to detect wider stack cycles."

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This reverts commit f5b0ed3c8c.
This commit is contained in:
Pedro Alves
2013-11-22 13:46:43 +00:00
parent 1bd122facc
commit c8381c86b4
1 changed files with 63 additions and 88 deletions
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151
gdb/frame.c
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@@ -188,31 +188,23 @@ frame_stash_create (void)
NULL);
}
/* Internal function to add a frame to the frame_stash hash table.
Returns false if a frame with the same ID was already stashed, true
otherwise. */
/* Internal function to add a frame to the frame_stash hash table. Do
not store frames below 0 as they may not have any addresses to
calculate a hash. */
static int
static void
frame_stash_add (struct frame_info *frame)
{
struct frame_info **slot;
/* Do not stash frames below level 0. */
if (frame->level >= 0)
{
struct frame_info **slot;
/* Do not try to stash the sentinel frame. */
gdb_assert (frame->level >= 0);
slot = (struct frame_info **) htab_find_slot (frame_stash,
frame,
INSERT);
/* If we already have a frame in the stack with the same id, we
either have a stack cycle (corrupted stack?), or some bug
elsewhere in GDB. In any case, ignore the duplicate and return
an indication to the caller. */
if (*slot != NULL)
return 0;
*slot = frame;
return 1;
slot = (struct frame_info **) htab_find_slot (frame_stash,
frame,
INSERT);
*slot = frame;
}
}
/* Internal function to search the frame stash for an entry with the
@@ -397,34 +389,6 @@ skip_artificial_frames (struct frame_info *frame)
return frame;
}
/* Compute the frame's uniq ID that can be used to, later, re-find the
frame. */
static void
compute_frame_id (struct frame_info *fi)
{
gdb_assert (!fi->this_id.p);
if (frame_debug)
fprintf_unfiltered (gdb_stdlog, "{ compute_frame_id (fi=%d) ",
fi->level);
/* Find the unwinder. */
if (fi->unwind == NULL)
frame_unwind_find_by_frame (fi, &fi->prologue_cache);
/* Find THIS frame's ID. */
/* Default to outermost if no ID is found. */
fi->this_id.value = outer_frame_id;
fi->unwind->this_id (fi, &fi->prologue_cache, &fi->this_id.value);
gdb_assert (frame_id_p (fi->this_id.value));
fi->this_id.p = 1;
if (frame_debug)
{
fprintf_unfiltered (gdb_stdlog, "-> ");
fprint_frame_id (gdb_stdlog, fi->this_id.value);
fprintf_unfiltered (gdb_stdlog, " }\n");
}
}
/* Return a frame uniq ID that can be used to, later, re-find the
frame. */
@@ -434,7 +398,29 @@ get_frame_id (struct frame_info *fi)
if (fi == NULL)
return null_frame_id;
gdb_assert (fi->this_id.p);
if (!fi->this_id.p)
{
if (frame_debug)
fprintf_unfiltered (gdb_stdlog, "{ get_frame_id (fi=%d) ",
fi->level);
/* Find the unwinder. */
if (fi->unwind == NULL)
frame_unwind_find_by_frame (fi, &fi->prologue_cache);
/* Find THIS frame's ID. */
/* Default to outermost if no ID is found. */
fi->this_id.value = outer_frame_id;
fi->unwind->this_id (fi, &fi->prologue_cache, &fi->this_id.value);
gdb_assert (frame_id_p (fi->this_id.value));
fi->this_id.p = 1;
if (frame_debug)
{
fprintf_unfiltered (gdb_stdlog, "-> ");
fprint_frame_id (gdb_stdlog, fi->this_id.value);
fprintf_unfiltered (gdb_stdlog, " }\n");
}
frame_stash_add (fi);
}
return fi->this_id.value;
}
@@ -1669,42 +1655,6 @@ frame_register_unwind_location (struct frame_info *this_frame, int regnum,
}
}
/* Get the previous raw frame, and check that it is not identical to
same other frame frame already in the chain. If it is, there is
most likely a stack cycle, so we discard it, and mark THIS_FRAME as
outermost, with UNWIND_SAME_ID stop reason. Unlike the other
validity tests, that compare THIS_FRAME and the next frame, we do
this right after creating the previous frame, to avoid ever ending
up with two frames with the same id in the frame chain. */
static struct frame_info *
get_prev_frame_if_no_cycle (struct frame_info *this_frame)
{
struct frame_info *prev_frame;
prev_frame = get_prev_frame_raw (this_frame);
if (prev_frame == NULL)
return NULL;
compute_frame_id (prev_frame);
if (frame_stash_add (prev_frame))
return prev_frame;
/* Another frame with the same id was already in the stash. We just
detected a cycle. */
if (frame_debug)
{
fprintf_unfiltered (gdb_stdlog, "-> ");
fprint_frame (gdb_stdlog, NULL);
fprintf_unfiltered (gdb_stdlog, " // this frame has same ID }\n");
}
this_frame->stop_reason = UNWIND_SAME_ID;
/* Unlink. */
prev_frame->next = NULL;
this_frame->prev = NULL;
return NULL;
}
/* Return a "struct frame_info" corresponding to the frame that called
THIS_FRAME. Returns NULL if there is no such frame.
@@ -1716,6 +1666,7 @@ get_prev_frame_1 (struct frame_info *this_frame)
{
struct frame_id this_id;
struct gdbarch *gdbarch;
struct frame_info *prev_frame;
gdb_assert (this_frame != NULL);
gdbarch = get_frame_arch (this_frame);
@@ -1758,7 +1709,7 @@ get_prev_frame_1 (struct frame_info *this_frame)
until we have unwound all the way down to the previous non-inline
frame. */
if (get_frame_type (this_frame) == INLINE_FRAME)
return get_prev_frame_if_no_cycle (this_frame);
return get_prev_frame_raw (this_frame);
/* Check that this frame is unwindable. If it isn't, don't try to
unwind to the prev frame. */
@@ -1864,7 +1815,31 @@ get_prev_frame_1 (struct frame_info *this_frame)
}
}
return get_prev_frame_if_no_cycle (this_frame);
prev_frame = get_prev_frame_raw (this_frame);
/* Check that this and the prev frame are not identical. If they
are, there is most likely a stack cycle. Unlike the tests above,
we do this right after creating the prev frame, to avoid ever
ending up with two frames with the same id in the frame
chain. */
if (prev_frame != NULL
&& frame_id_eq (get_frame_id (prev_frame),
get_frame_id (this_frame)))
{
if (frame_debug)
{
fprintf_unfiltered (gdb_stdlog, "-> ");
fprint_frame (gdb_stdlog, NULL);
fprintf_unfiltered (gdb_stdlog, " // this frame has same ID }\n");
}
this_frame->stop_reason = UNWIND_SAME_ID;
/* Unlink. */
prev_frame->next = NULL;
this_frame->prev = NULL;
return NULL;
}
return prev_frame;
}
/* Construct a new "struct frame_info" and link it previous to