binutils-gdb/gdb/nat/windows-nat.h

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/* Internal interfaces for the Windows code
Copyright (C) 1995-2020 Free Software Foundation, Inc.
This file is part of GDB.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
#ifndef NAT_WINDOWS_NAT_H
#define NAT_WINDOWS_NAT_H
#include <windows.h>
/* Thread information structure used to track extra information about
each thread. */
struct windows_thread_info
{
windows_thread_info (DWORD tid_, HANDLE h_, CORE_ADDR tlb)
: tid (tid_),
h (h_),
thread_local_base (tlb)
{
}
DISABLE_COPY_AND_ASSIGN (windows_thread_info);
/* Ensure that this thread has been suspended. */
void suspend ();
/* Resume the thread if it has been suspended. */
void resume ();
/* The Win32 thread identifier. */
DWORD tid;
/* The handle to the thread. */
HANDLE h;
/* Thread Information Block address. */
CORE_ADDR thread_local_base;
/* This keeps track of whether SuspendThread was called on this
thread. -1 means there was a failure or that the thread was
explicitly not suspended, 1 means it was called, and 0 means it
was not. */
int suspended = 0;
#ifdef _WIN32_WCE
/* The context as retrieved right after suspending the thread. */
CONTEXT base_context {};
#endif
/* The context of the thread, including any manipulations. */
union
{
CONTEXT context {};
#ifdef __x86_64__
WOW64_CONTEXT wow64_context;
#endif
};
/* Whether debug registers changed since we last set CONTEXT back to
the thread. */
bool debug_registers_changed = false;
/* Nonzero if CONTEXT is invalidated and must be re-read from the
inferior thread. */
bool reload_context = false;
Handle pending stops from the Windows kernel PR gdb/22992 concerns an assertion failure in gdb when debugging a certain inferior: int finish_step_over(execution_control_state*): Assertion `ecs->event_thread->control.trap_expected' failed. Initially the investigation centered on the discovery that gdb was not suspending other threads when attempting to single-step. This oversight is corrected in this patch: now, when stepping a thread, gdb will call SuspendThread on all other threads. However, the bug persisted even after this change. In particular, WaitForDebugEvent could see a stop for a thread that was ostensibly suspended. Our theory of what is happening here is that there are actually simultaneous breakpoint hits, and the Windows kernel queues the events, causing the second stop to be reported on a suspended thread. In Windows 10 or later gdb could use the DBG_REPLY_LATER flag to ContinueDebugEvent to request that such events be re-reported later. However, relying on that did not seem advisable, so this patch instead arranges to queue such "pending" stops, and then to report them later, once the step has completed. In the PR, Pedro pointed out that it's best in this scenario to implement the stopped_by_sw_breakpoint method, so this patch does this as well. gdb/ChangeLog 2020-04-08 Tom Tromey <tromey@adacore.com> PR gdb/22992 * windows-nat.c (current_event): Update comment. (last_wait_event, desired_stop_thread_id): New globals. (struct pending_stop): New. (pending_stops): New global. (windows_nat_target) <stopped_by_sw_breakpoint> <supports_stopped_by_sw_breakpoint>: New methods. (windows_fetch_one_register): Add assertions. Adjust PC. (windows_continue): Handle pending stops. Suspend other threads when stepping. Use last_wait_event (wait_for_debug_event): New function. (get_windows_debug_event): Use wait_for_debug_event. Handle pending stops. Queue spurious stops. (windows_nat_target::wait): Set stopped_at_software_breakpoint. (windows_nat_target::kill): Use wait_for_debug_event. * nat/windows-nat.h (struct windows_thread_info) <stopped_at_software_breakpoint>: New field. * nat/windows-nat.c (windows_thread_info::resume): Clear stopped_at_software_breakpoint.
2020-04-09 04:33:35 +08:00
/* True if this thread is currently stopped at a software
breakpoint. This is used to offset the PC when needed. */
bool stopped_at_software_breakpoint = false;
/* The name of the thread, allocated by xmalloc. */
gdb::unique_xmalloc_ptr<char> name;
};
#endif