/* The process and thread handles for the above context. */
-static DEBUG_EVENT current_event; /* The current debug event from
- WaitForDebugEvent */
+/* The current debug event from WaitForDebugEvent or from a pending
+ stop. */
+static DEBUG_EVENT current_event;
+
+/* The most recent event from WaitForDebugEvent. Unlike
+ current_event, this is guaranteed never to come from a pending
+ stop. This is important because only data from the most recent
+ event from WaitForDebugEvent can be used when calling
+ ContinueDebugEvent. */
+static DEBUG_EVENT last_wait_event;
+
static HANDLE current_process_handle; /* Currently executing process */
static windows_thread_info *current_thread; /* Info on currently selected thread */
static EXCEPTION_RECORD siginfo_er; /* Contents of $_siginfo */
#endif /* 0 */
+/* The ID of the thread for which we anticipate a stop event.
+ Normally this is -1, meaning we'll accept an event in any
+ thread. */
+static DWORD desired_stop_thread_id = -1;
+
+/* A single pending stop. See "pending_stops" for more
+ information. */
+struct pending_stop
+{
+ /* The thread id. */
+ DWORD thread_id;
+
+ /* The target waitstatus we computed. */
+ target_waitstatus status;
+
+ /* The event. A few fields of this can be referenced after a stop,
+ and it seemed simplest to store the entire event. */
+ DEBUG_EVENT event;
+};
+
+/* A vector of pending stops. Sometimes, Windows will report a stop
+ on a thread that has been ostensibly suspended. We believe what
+ happens here is that two threads hit a breakpoint simultaneously,
+ and the Windows kernel queues the stop events. However, this can
+ result in the strange effect of trying to single step thread A --
+ leaving all other threads suspended -- and then seeing a stop in
+ thread B. To handle this scenario, we queue all such "pending"
+ stops here, and then process them once the step has completed. See
+ PR gdb/22992. */
+static std::vector<pending_stop> pending_stops;
+
struct windows_nat_target final : public x86_nat_target<inf_child_target>
{
void close () override;
void fetch_registers (struct regcache *, int) override;
void store_registers (struct regcache *, int) override;
+ bool stopped_by_sw_breakpoint () override
+ {
+ return current_thread->stopped_at_software_breakpoint;
+ }
+
+ bool supports_stopped_by_sw_breakpoint () override
+ {
+ return true;
+ }
+
enum target_xfer_status xfer_partial (enum target_object object,
const char *annex,
gdb_byte *readbuf,
struct gdbarch *gdbarch = regcache->arch ();
struct gdbarch_tdep *tdep = gdbarch_tdep (gdbarch);
+ gdb_assert (!gdbarch_read_pc_p (gdbarch));
+ gdb_assert (gdbarch_pc_regnum (gdbarch) >= 0);
+ gdb_assert (!gdbarch_write_pc_p (gdbarch));
+
if (r == I387_FISEG_REGNUM (tdep))
{
long l = *((long *) context_offset) & 0xffff;
regcache->raw_supply (r, (char *) &l);
}
else
- regcache->raw_supply (r, context_offset);
+ {
+ if (th->stopped_at_software_breakpoint
+ && r == gdbarch_pc_regnum (gdbarch))
+ {
+ int size = register_size (gdbarch, r);
+ if (size == 4)
+ {
+ uint32_t value;
+ memcpy (&value, context_offset, size);
+ value -= gdbarch_decr_pc_after_break (gdbarch);
+ memcpy (context_offset, &value, size);
+ }
+ else
+ {
+ gdb_assert (size == 8);
+ uint64_t value;
+ memcpy (&value, context_offset, size);
+ value -= gdbarch_decr_pc_after_break (gdbarch);
+ memcpy (context_offset, &value, size);
+ }
+ }
+ regcache->raw_supply (r, context_offset);
+ }
}
void
{
BOOL res;
+ desired_stop_thread_id = id;
+
+ /* If there are pending stops, and we might plausibly hit one of
+ them, we don't want to actually continue the inferior -- we just
+ want to report the stop. In this case, we just pretend to
+ continue. See the comment by the definition of "pending_stops"
+ for details on why this is needed. */
+ for (const auto &item : pending_stops)
+ {
+ if (desired_stop_thread_id == -1
+ || desired_stop_thread_id == item.thread_id)
+ {
+ DEBUG_EVENTS (("windows_continue - pending stop anticipated, "
+ "desired=0x%x, item=0x%x\n",
+ desired_stop_thread_id, item.thread_id));
+ return TRUE;
+ }
+ }
+
DEBUG_EVENTS (("ContinueDebugEvent (cpid=%d, ctid=0x%x, %s);\n",
- (unsigned) current_event.dwProcessId,
- (unsigned) current_event.dwThreadId,
+ (unsigned) last_wait_event.dwProcessId,
+ (unsigned) last_wait_event.dwThreadId,
continue_status == DBG_CONTINUE ?
"DBG_CONTINUE" : "DBG_EXCEPTION_NOT_HANDLED"));
for (windows_thread_info *th : thread_list)
- if ((id == -1 || id == (int) th->tid)
- && th->suspended)
+ if (id == -1 || id == (int) th->tid)
{
+ if (!th->suspended)
+ continue;
#ifdef __x86_64__
if (wow64_process)
{
}
th->resume ();
}
+ else
+ {
+ /* When single-stepping a specific thread, other threads must
+ be suspended. */
+ th->suspend ();
+ }
- res = ContinueDebugEvent (current_event.dwProcessId,
- current_event.dwThreadId,
+ res = ContinueDebugEvent (last_wait_event.dwProcessId,
+ last_wait_event.dwThreadId,
continue_status);
if (!res)
return TRUE;
}
+/* A wrapper for WaitForDebugEvent that sets "last_wait_event"
+ appropriately. */
+static BOOL
+wait_for_debug_event (DEBUG_EVENT *event, DWORD timeout)
+{
+ BOOL result = WaitForDebugEvent (event, timeout);
+ if (result)
+ last_wait_event = *event;
+ return result;
+}
+
/* Get the next event from the child. Returns a non-zero thread id if the event
requires handling by WFI (or whatever). */
static windows_thread_info dummy_thread_info (0, 0, 0);
DWORD thread_id = 0;
+ /* If there is a relevant pending stop, report it now. See the
+ comment by the definition of "pending_stops" for details on why
+ this is needed. */
+ for (auto iter = pending_stops.begin ();
+ iter != pending_stops.end ();
+ ++iter)
+ {
+ if (desired_stop_thread_id == -1
+ || desired_stop_thread_id == iter->thread_id)
+ {
+ thread_id = iter->thread_id;
+ *ourstatus = iter->status;
+ current_event = iter->event;
+
+ inferior_ptid = ptid_t (current_event.dwProcessId, thread_id, 0);
+ current_thread = thread_rec (thread_id, INVALIDATE_CONTEXT);
+ current_thread->reload_context = 1;
+
+ DEBUG_EVENTS (("get_windows_debug_event - "
+ "pending stop found in 0x%x (desired=0x%x)\n",
+ thread_id, desired_stop_thread_id));
+
+ pending_stops.erase (iter);
+ return thread_id;
+ }
+ }
+
last_sig = GDB_SIGNAL_0;
- if (!(debug_event = WaitForDebugEvent (¤t_event, 1000)))
+ if (!(debug_event = wait_for_debug_event (¤t_event, 1000)))
goto out;
event_count++;
if (!thread_id || saw_create != 1)
{
- CHECK (windows_continue (continue_status, -1, 0));
+ CHECK (windows_continue (continue_status, desired_stop_thread_id, 0));
+ }
+ else if (desired_stop_thread_id != -1 && desired_stop_thread_id != thread_id)
+ {
+ /* Pending stop. See the comment by the definition of
+ "pending_stops" for details on why this is needed. */
+ DEBUG_EVENTS (("get_windows_debug_event - "
+ "unexpected stop in 0x%x (expecting 0x%x)\n",
+ thread_id, desired_stop_thread_id));
+
+ if (current_event.dwDebugEventCode == EXCEPTION_DEBUG_EVENT
+ && (current_event.u.Exception.ExceptionRecord.ExceptionCode
+ == EXCEPTION_BREAKPOINT)
+ && windows_initialization_done)
+ {
+ th = thread_rec (thread_id, INVALIDATE_CONTEXT);
+ th->stopped_at_software_breakpoint = true;
+ }
+ pending_stops.push_back ({thread_id, *ourstatus, current_event});
+ thread_id = 0;
+ CHECK (windows_continue (continue_status, desired_stop_thread_id, 0));
}
else
{
SetConsoleCtrlHandler (&ctrl_c_handler, FALSE);
if (retval)
- return ptid_t (current_event.dwProcessId, retval, 0);
+ {
+ ptid_t result = ptid_t (current_event.dwProcessId, retval, 0);
+
+ if (current_thread != nullptr)
+ {
+ current_thread->stopped_at_software_breakpoint = false;
+ if (current_event.dwDebugEventCode == EXCEPTION_DEBUG_EVENT
+ && (current_event.u.Exception.ExceptionRecord.ExceptionCode
+ == EXCEPTION_BREAKPOINT)
+ && windows_initialization_done)
+ current_thread->stopped_at_software_breakpoint = true;
+ }
+
+ return result;
+ }
else
{
int detach = 0;
{
if (!windows_continue (DBG_CONTINUE, -1, 1))
break;
- if (!WaitForDebugEvent (¤t_event, INFINITE))
+ if (!wait_for_debug_event (¤t_event, INFINITE))
break;
if (current_event.dwDebugEventCode == EXIT_PROCESS_DEBUG_EVENT)
break;
projects / binutils-gdb.git / commitdiff