gdbstub: add reverse continue support in replay mode

This patch adds support of the reverse continue operation for gdbstub.
Reverse continue finds the last breakpoint that would happen in normal
execution from the beginning to the current moment.
Implementation of the reverse continue replays the execution twice:
to find the breakpoints that were hit and to seek to the last breakpoint.
Reverse continue loads the previous snapshot and tries to find the breakpoint
since that moment. If there are no such breakpoints, it proceeds to
the earlier snapshot, and so on. When no breakpoints or watchpoints were
hit at all, execution stops at the beginning of the replay log.

Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgalyuk@ispras.ru>
Message-Id: <160174522930.12451.6994758004725016836.stgit@pasha-ThinkPad-X280>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Pavel Dovgalyuk 2020-10-03 20:13:49 +03:00 committed by Paolo Bonzini
parent fda8458bd3
commit cda382594b
6 changed files with 100 additions and 1 deletions

View file

@ -1907,6 +1907,13 @@ static void handle_backward(GdbCmdContext *gdb_ctx, void *user_ctx)
put_packet("E14");
}
return;
case 'c':
if (replay_reverse_continue()) {
gdb_continue();
} else {
put_packet("E14");
}
return;
}
}
@ -2161,7 +2168,8 @@ static void handle_query_supported(GdbCmdContext *gdb_ctx, void *user_ctx)
}
if (replay_mode == REPLAY_MODE_PLAY) {
g_string_append(gdbserver_state.str_buf, ";ReverseStep+");
g_string_append(gdbserver_state.str_buf,
";ReverseStep+;ReverseContinue+");
}
if (gdb_ctx->num_params &&