This is the mail archive of the
gdb-patches@sourceware.org
mailing list for the GDB project.
[PATCH 4/9] Reset *THIS_CACHE in frame_unwind_try_unwinder in case of exception
- From: Yao Qi <qiyaoltc at gmail dot com>
- To: gdb-patches at sourceware dot org
- Date: Mon, 31 Jul 2017 23:21:50 +0100
- Subject: [PATCH 4/9] Reset *THIS_CACHE in frame_unwind_try_unwinder in case of exception
- Authentication-results: sourceware.org; auth=none
- References: <1501539715-8049-1-git-send-email-yao.qi@linaro.org>
It is required that unwinder->sniffer should set *this_cache to NULL if
the unwinder is not applicable or exception is thrown, so
78ac5f831692f70b841044961069e50d4ba6a76f adds clear_pointer_cleanup to set
*this_cache to NULL in case of exception in order to fix PR 14100.
https://sourceware.org/ml/gdb-patches/2012-08/msg00075.html
This patch removes that clear_pointer_cleanup, and catch all exception in
the caller of unwinder->sniffer. In case of exception, reset *this_case.
gdb:
2017-07-20 Yao Qi <yao.qi@linaro.org>
* dwarf2-frame.c (clear_pointer_cleanup): Remove.
(dwarf2_frame_cache): Remove reset_cache_cleanup.
(dwarf2_frame_cache):
* frame-unwind.c (frame_unwind_try_unwinder): Catch
RETURN_MASK_ALL and set *this_case to NULL.
* frame-unwind.h: Update comments.
---
gdb/dwarf2-frame.c | 14 --------------
gdb/frame-unwind.c | 7 ++++++-
gdb/frame-unwind.h | 3 ++-
3 files changed, 8 insertions(+), 16 deletions(-)
diff --git a/gdb/dwarf2-frame.c b/gdb/dwarf2-frame.c
index 0cb40d9..f8e6522 100644
--- a/gdb/dwarf2-frame.c
+++ b/gdb/dwarf2-frame.c
@@ -960,20 +960,9 @@ struct dwarf2_frame_cache
int entry_cfa_sp_offset_p;
};
-/* A cleanup that sets a pointer to NULL. */
-
-static void
-clear_pointer_cleanup (void *arg)
-{
- void **ptr = (void **) arg;
-
- *ptr = NULL;
-}
-
static struct dwarf2_frame_cache *
dwarf2_frame_cache (struct frame_info *this_frame, void **this_cache)
{
- struct cleanup *reset_cache_cleanup;
struct gdbarch *gdbarch = get_frame_arch (this_frame);
const int num_regs = gdbarch_num_regs (gdbarch)
+ gdbarch_num_pseudo_regs (gdbarch);
@@ -989,7 +978,6 @@ dwarf2_frame_cache (struct frame_info *this_frame, void **this_cache)
cache = FRAME_OBSTACK_ZALLOC (struct dwarf2_frame_cache);
cache->reg = FRAME_OBSTACK_CALLOC (num_regs, struct dwarf2_frame_state_reg);
*this_cache = cache;
- reset_cache_cleanup = make_cleanup (clear_pointer_cleanup, this_cache);
/* Unwind the PC.
@@ -1078,7 +1066,6 @@ dwarf2_frame_cache (struct frame_info *this_frame, void **this_cache)
if (ex.error == NOT_AVAILABLE_ERROR)
{
cache->unavailable_retaddr = 1;
- discard_cleanups (reset_cache_cleanup);
return cache;
}
@@ -1184,7 +1171,6 @@ incomplete CFI data; unspecified registers (e.g., %s) at %s"),
&& fs.regs.reg[fs.retaddr_column].how == DWARF2_FRAME_REG_UNDEFINED)
cache->undefined_retaddr = 1;
- discard_cleanups (reset_cache_cleanup);
return cache;
}
diff --git a/gdb/frame-unwind.c b/gdb/frame-unwind.c
index 4d21349..3a75013 100644
--- a/gdb/frame-unwind.c
+++ b/gdb/frame-unwind.c
@@ -106,8 +106,11 @@ frame_unwind_try_unwinder (struct frame_info *this_frame, void **this_cache,
{
res = unwinder->sniffer (unwinder, this_frame, this_cache);
}
- CATCH (ex, RETURN_MASK_ERROR)
+ CATCH (ex, RETURN_MASK_ALL)
{
+ /* Catch all exceptions, caused by either interrupt or error.
+ Reset *THIS_CACHE. */
+ *this_cache = NULL;
if (ex.error == NOT_AVAILABLE_ERROR)
{
/* This usually means that not even the PC is available,
@@ -128,6 +131,8 @@ frame_unwind_try_unwinder (struct frame_info *this_frame, void **this_cache,
}
else
{
+ /* Don't set *THIS_CACHE to NULL here, because sniffer has to do
+ so. */
do_cleanups (old_cleanup);
return 0;
}
diff --git a/gdb/frame-unwind.h b/gdb/frame-unwind.h
index 4588cef..8226b6d 100644
--- a/gdb/frame-unwind.h
+++ b/gdb/frame-unwind.h
@@ -46,7 +46,8 @@ struct value;
the PC and attributes) and if SELF is the applicable unwinder,
return non-zero. Possibly also initialize THIS_PROLOGUE_CACHE; but
only if returning 1. Initializing THIS_PROLOGUE_CACHE in other
- cases (0 return, or exception) is invalid. */
+ cases (0 return) is invalid. In case of exception, the caller has
+ to set *THIS_PROLOGUE_CACHE to NULL. */
typedef int (frame_sniffer_ftype) (const struct frame_unwind *self,
struct frame_info *this_frame,
--
1.9.1