gdb/gdb-6.3-ia64-sigtramp-fp-20050926.patch

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2005-09-27 Jeff Johnston <jjohnstn@redhat.com>
* libunwind-frame.c (libunwind_frame_cache): Save the current
stack pointer in the cache.
(libunwind_sigtramp_frame_this_id): New function.
(libunwind_sigtramp_frame_unwind): New unwinder.
(libunwind_sigtramp_frame_sniffer): Return
libunwind_sigtramp_frame_unwind address.
* libunwind-frame.h (libunwind_sigtramp_frame_this_id): New
prototype.
* ia64-tdep.c (ia64_libunwind_sigtramp_frame_this_id): Calculate
the base address using the current stack pointer plus a fixed
offset.
Index: gdb-6.5/gdb/libunwind-frame.c
===================================================================
--- gdb-6.5.orig/gdb/libunwind-frame.c 2006-07-07 03:04:32.000000000 -0300
+++ gdb-6.5/gdb/libunwind-frame.c 2006-07-07 03:07:33.000000000 -0300
@@ -62,6 +62,7 @@ static unw_word_t (*unw_find_dyn_list_p)
struct libunwind_frame_cache
{
CORE_ADDR base;
+ CORE_ADDR sp;
CORE_ADDR func_addr;
unw_cursor_t cursor;
};
@@ -131,7 +132,7 @@ libunwind_frame_cache (struct frame_info
unw_accessors_t *acc;
unw_addr_space_t as;
unw_cursor_t *cursor_addr;
- unw_word_t fp;
+ unw_word_t fp, sp;
unw_regnum_t uw_sp_regnum;
struct libunwind_frame_cache *cache;
struct libunwind_descr *descr;
@@ -176,15 +177,28 @@ libunwind_frame_cache (struct frame_info
else /* make copy */
cache->cursor = *cursor_addr;
+ /* For the base address, we have a small problem. The majority
+ of the time, we can get the stack pointer of the previous
+ frame to use as a frame pointer. In the case where we have
+ a signal trampoline, the stack may change due to a sigaltstack
+ being set up. In that case, the normal mechanism will give us
+ an address in the regular stack which is not at the end of the
+ sigaltstack as we want. To handle this, we record the stack
+ address so the caller may calculate a more correct base address
+ to use. */
+ uw_sp_regnum = descr->gdb2uw (SP_REGNUM);
+ ret = unw_get_reg_p (&cache->cursor, uw_sp_regnum, &sp);
+ if (ret < 0)
+ error ("Can't get libunwind sp register.");
+
if (unw_step_p (&cache->cursor) < 0)
return NULL;
- /* To get base address, get sp from previous frame. */
- uw_sp_regnum = descr->gdb2uw (SP_REGNUM);
ret = unw_get_reg_p (&cache->cursor, uw_sp_regnum, &fp);
if (ret < 0)
error (_("Can't get libunwind sp register."));
+ cache->sp = (CORE_ADDR)sp;
cache->base = (CORE_ADDR)fp;
*this_cache = cache;
@@ -371,6 +385,31 @@ libunwind_search_unwind_table (void *as,
di, pi, need_unwind_info, args);
}
+void
+libunwind_sigtramp_frame_this_id (struct frame_info *next_frame,
+ void **this_cache,
+ struct frame_id *this_id)
+{
+ struct libunwind_frame_cache *cache =
+ libunwind_frame_cache (next_frame, this_cache);
+
+ /* Unlike a regular frame, we can't use the normal frame pointer
+ mechanism because a sigaltstack may have been used. Instead,
+ we return the current stack pointer for the caller to use
+ to calculate the base address. */
+ if (cache != NULL)
+ (*this_id) = frame_id_build (cache->sp, cache->func_addr);
+ else
+ (*this_id) = null_frame_id;
+}
+
+static const struct frame_unwind libunwind_sigtramp_frame_unwind =
+{
+ SIGTRAMP_FRAME,
+ libunwind_sigtramp_frame_this_id,
+ libunwind_frame_prev_register
+};
+
/* Verify if we are in a sigtramp frame and we can use libunwind to unwind. */
const struct frame_unwind *
libunwind_sigtramp_frame_sniffer (struct frame_info *next_frame)
@@ -403,7 +442,7 @@ libunwind_sigtramp_frame_sniffer (struct
/* Check to see if we are in a signal frame. */
ret = unw_is_signal_frame_p (&cursor);
if (ret > 0)
- return &libunwind_frame_unwind;
+ return &libunwind_sigtramp_frame_unwind;
return NULL;
}
Index: gdb-6.5/gdb/libunwind-frame.h
===================================================================
--- gdb-6.5.orig/gdb/libunwind-frame.h 2006-07-07 02:51:32.000000000 -0300
+++ gdb-6.5/gdb/libunwind-frame.h 2006-07-07 03:05:49.000000000 -0300
@@ -49,6 +49,9 @@ void libunwind_frame_set_descr (struct g
void libunwind_frame_this_id (struct frame_info *next_frame, void **this_cache,
struct frame_id *this_id);
+void libunwind_sigtramp_frame_this_id (struct frame_info *next_frame,
+ void **this_cache,
+ struct frame_id *this_id);
void libunwind_frame_prev_register (struct frame_info *next_frame, void **this_cache,
int regnum, int *optimizedp,
enum lval_type *lvalp, CORE_ADDR *addrp,
Index: gdb-6.5/gdb/ia64-tdep.c
===================================================================
--- gdb-6.5.orig/gdb/ia64-tdep.c 2006-07-07 02:51:32.000000000 -0300
+++ gdb-6.5/gdb/ia64-tdep.c 2006-07-07 03:05:49.000000000 -0300
@@ -3031,7 +3031,7 @@ ia64_libunwind_sigtramp_frame_this_id (s
struct frame_id id;
CORE_ADDR prev_ip;
- libunwind_frame_this_id (next_frame, this_cache, &id);
+ libunwind_sigtramp_frame_this_id (next_frame, this_cache, &id);
if (frame_id_eq (id, null_frame_id))
{
(*this_id) = null_frame_id;
@@ -3043,8 +3043,14 @@ ia64_libunwind_sigtramp_frame_this_id (s
frame_unwind_register (next_frame, IA64_BSP_REGNUM, buf);
bsp = extract_unsigned_integer (buf, 8);
- /* For a sigtramp frame, we don't make the check for previous ip being 0. */
- (*this_id) = frame_id_build_special (id.stack_addr, id.code_addr, bsp);
+ /* For a sigtramp frame, we don't make the check for previous ip being 0.
+ We also must calculate the frame pointer because libunwind will give
+ us back the current stack pointer instead of the frame pointer since
+ it cannot figure this out when in a sigaltstack. We make a basic
+ assumption of 16 (default size) + 8 bytes for sigcontext address.
+ FIXME: if libunwind were to export the frame pointer address, we
+ could eliminate the assumption and get the actual value. */
+ (*this_id) = frame_id_build_special (id.stack_addr + 24, id.code_addr, bsp);
if (gdbarch_debug >= 1)
fprintf_unfiltered (gdb_stdlog,