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| author | Pedro Alves <pedro@palves.net> | 2023-05-09 10:27:04 +0100 |
|---|---|---|
| committer | Pedro Alves <pedro@palves.net> | 2024-05-08 00:39:56 +0100 |
| commit | 552616cbb7d24d81690da17a30d067f59993f289 (patch) | |
| tree | d42f45f3d0c29083d5595697c901f245eb4e87bc | |
| parent | 87e727c0c64e2a45ef48452884b2c07f3a79c516 (diff) | |
| download | gdb-552616cbb7d24d81690da17a30d067f59993f289.zip gdb-552616cbb7d24d81690da17a30d067f59993f289.tar.gz gdb-552616cbb7d24d81690da17a30d067f59993f289.tar.bz2 | |
Windows gdb+gdbserver: Move suspending thread to when returning event
The current code suspends a thread just before calling
GetThreadContext. You can only call GetThreadContext if the thread is
suspended. But, after WaitForDebugEvent, all threads are implicitly
suspended. So I don't think we even needed to call SuspendThread
explictly at all before our GetThreadContext calls.
However, suspending threads when we're about to present a stop to gdb
simplifies adding non-stop support later. This way, the windows
SuspendThread state corresponds to whether a thread is suspended or
resumed from the core's perspective. Curiously, I noticed that Wine's
winedbg does something similar:
https://github.com/wine-mirror/wine/blob/234943344f7495d1e072338f0e06fa2d5cbf0aa1/programs/winedbg/gdbproxy.c#L651
This makes it much easier to reason about a thread's suspend state,
and simplifies adding non-stop mode later on.
Change-Id: Ifd6889a8afc041fad33cd1c4500e38941da6781b
| -rw-r--r-- | gdb/windows-nat.c | 13 | ||||
| -rw-r--r-- | gdbserver/win32-low.cc | 5 |
2 files changed, 10 insertions, 8 deletions
diff --git a/gdb/windows-nat.c b/gdb/windows-nat.c index 9730377..aa531c4 100644 --- a/gdb/windows-nat.c +++ b/gdb/windows-nat.c @@ -710,7 +710,6 @@ windows_nat_target::fetch_registers (struct regcache *regcache, int r) { if (th->wow64_context.ContextFlags == 0) { - th->suspend (); th->wow64_context.ContextFlags = CONTEXT_DEBUGGER_DR; CHECK (Wow64GetThreadContext (th->h, &th->wow64_context)); } @@ -720,7 +719,6 @@ windows_nat_target::fetch_registers (struct regcache *regcache, int r) { if (th->context.ContextFlags == 0) { - th->suspend (); th->context.ContextFlags = CONTEXT_DEBUGGER_DR; CHECK (GetThreadContext (th->h, &th->context)); } @@ -1320,12 +1318,6 @@ windows_nat_target::windows_continue (DWORD continue_status, int id, } th->resume (); } - else - { - /* When single-stepping a specific thread, other threads must - be suspended. */ - th->suspend (); - } std::optional<unsigned> err; do_synchronously ([&] () @@ -1816,6 +1808,11 @@ windows_nat_target::wait (ptid_t ptid, struct target_waitstatus *ourstatus, th->stopped_at_software_breakpoint = true; th->pc_adjusted = false; } + + /* All-stop, suspend all threads until they are + explicitly resumed. */ + for (auto &thr : windows_process.thread_list) + thr->suspend (); } return result; diff --git a/gdbserver/win32-low.cc b/gdbserver/win32-low.cc index 0d67cd9..8dd8f21 100644 --- a/gdbserver/win32-low.cc +++ b/gdbserver/win32-low.cc @@ -1226,6 +1226,11 @@ win32_process_target::wait (ptid_t ptid, target_waitstatus *ourstatus, OUTMSG2 (("Child Stopped with signal = %d \n", ourstatus->sig ())); maybe_adjust_pc (); + + /* All-stop, suspend all threads until they are explicitly + resumed. */ + for_each_thread (suspend_one_thread); + return debug_event_ptid (&windows_process.current_event); } default: |