diff options
Diffstat (limited to 'gdb')
| -rw-r--r-- | gdb/ChangeLog | 12 | ||||
| -rw-r--r-- | gdb/frame.c | 151 |
2 files changed, 100 insertions, 63 deletions
diff --git a/gdb/ChangeLog b/gdb/ChangeLog index e72097f..07c8efd 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,4 +1,16 @@ 2013-11-22 Pedro Alves <palves@redhat.com> + Tom Tromey <tromey@redhat.com> + + * frame.c (frame_stash_add): Now returns whether a frame with the + same ID was already known. + (compute_frame_id): New function, factored out from get_frame_id. + (get_frame_id): No longer lazilly compute the frame id here. + (get_prev_frame_if_no_cycle): New function. Detects wider stack + cycles. + (get_prev_frame_1): Use it instead of get_prev_frame_raw directly, + and checking for stack cycles here. + +2013-11-22 Pedro Alves <palves@redhat.com> PR 16155 * frame.c (get_prev_frame_1): Do the UNWIND_SAME_ID check between diff --git a/gdb/frame.c b/gdb/frame.c index 535a5a6..f77ce75 100644 --- a/gdb/frame.c +++ b/gdb/frame.c @@ -188,23 +188,31 @@ frame_stash_create (void) NULL); } -/* 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. */ +/* 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. */ -static void +static int frame_stash_add (struct frame_info *frame) { - /* Do not stash frames below level 0. */ - if (frame->level >= 0) - { - struct frame_info **slot; + struct frame_info **slot; - slot = (struct frame_info **) htab_find_slot (frame_stash, - frame, - INSERT); - *slot = frame; - } + /* 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; } /* Internal function to search the frame stash for an entry with the @@ -389,6 +397,34 @@ 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. */ @@ -398,29 +434,7 @@ get_frame_id (struct frame_info *fi) if (fi == NULL) return null_frame_id; - 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); - } - + gdb_assert (fi->this_id.p); return fi->this_id.value; } @@ -1655,6 +1669,42 @@ 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. @@ -1666,7 +1716,6 @@ 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); @@ -1709,7 +1758,7 @@ 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_raw (this_frame); + return get_prev_frame_if_no_cycle (this_frame); /* Check that this frame is unwindable. If it isn't, don't try to unwind to the prev frame. */ @@ -1815,31 +1864,7 @@ get_prev_frame_1 (struct frame_info *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; + return get_prev_frame_if_no_cycle (this_frame); } /* Construct a new "struct frame_info" and link it previous to |