Thread safety changes in debugserver and also in the process GDB remote plugin.

I added support for asking if the GDB remote server supports thread suffixes
for packets that should be thread specific (register read/write packets) because
the way the GDB remote protocol does it right now is to have a notion of a
current thread for register and memory reads/writes (set via the "$Hg%x" packet)
and a current thread for running ("$Hc%x"). Now we ask the remote GDB server
if it supports adding the thread ID to the register packets and we enable
that feature in LLDB if supported. This stops us from having to send a bunch
of packets that update the current thread ID to some value which is prone to
error, or extra packets.

llvm-svn: 123762

1 files changed, 40 insertions, 51 deletions

diff --git a/lldb/tools/debugserver/source/MacOSX/MachThread.cpp b/lldb/tools/debugserver/source/MacOSX/MachThread.cpp
index 7890c069a77..003a58b79d6 100644
--- a/lldb/tools/debugserver/source/MacOSX/MachThread.cpp
+++ b/lldb/tools/debugserver/source/MacOSX/MachThread.cpp
@@ -339,6 +339,12 @@ MachThread::ThreadWillResume(const DNBThreadResumeAction *thread_action)
     m_stop_exception.Clear();
 }
 
+nub_break_t
+MachThread::CurrentBreakpoint()
+{
+    return m_process->Breakpoints().FindIDByAddress(GetPC());
+}
+
 bool
 MachThread::ShouldStop(bool &step_more)
 {
@@ -394,14 +400,18 @@ MachThread::ShouldStop(bool &step_more)
 bool
 MachThread::IsStepping()
 {
+#if ENABLE_AUTO_STEPPING_OVER_BP
     // Return true if this thread is currently being stepped.
     // MachThread::ThreadWillResume currently determines this by looking if we
     // have been asked to single step, or if we are at a breakpoint instruction
     // and have been asked to resume. In the latter case we need to disable the
     // breakpoint we are at, single step, re-enable and continue.
     nub_state_t state = GetState();
-    return    (state == eStateStepping) ||
-            (state == eStateRunning && NUB_BREAK_ID_IS_VALID(CurrentBreakpoint()));
+    return ((state == eStateStepping) ||
+            (state == eStateRunning && NUB_BREAK_ID_IS_VALID(CurrentBreakpoint())));
+#else
+    return GetState() == eStateStepping;
+#endif
 }
 
 
@@ -430,6 +440,7 @@ MachThread::ThreadDidStop()
     // Update the basic information for a thread
     MachThread::GetBasicInfo(m_tid, &m_basicInfo);
 
+#if ENABLE_AUTO_STEPPING_OVER_BP
     // See if we were at a breakpoint when we last resumed that we disabled,
     // re-enable it.
     nub_break_t breakID = CurrentBreakpoint();
@@ -469,10 +480,12 @@ MachThread::ThreadDidStop()
             SetState(eStateStopped);
         }
     }
-
-
-    SetCurrentBreakpoint(INVALID_NUB_BREAK_ID);
-
+#else
+    if (m_basicInfo.suspend_count > 0)
+        SetState(eStateSuspended);
+    else
+        SetState(eStateStopped);
+#endif
     return true;
 }
 
@@ -496,30 +509,27 @@ MachThread::NotifyException(MachException::Data& exc)
     if (!handled)
     {
         handled = true;
-        nub_addr_t pc = GetPC();
-        nub_break_t breakID = m_process->Breakpoints().FindIDByAddress(pc);
-        SetCurrentBreakpoint(breakID);
-        switch (exc.exc_type)
-        {
-        case EXC_BAD_ACCESS:
-            break;
-        case EXC_BAD_INSTRUCTION:
-            break;
-        case EXC_ARITHMETIC:
-            break;
-        case EXC_EMULATION:
-            break;
-        case EXC_SOFTWARE:
-            break;
-        case EXC_BREAKPOINT:
-            break;
-        case EXC_SYSCALL:
-            break;
-        case EXC_MACH_SYSCALL:
-            break;
-        case EXC_RPC_ALERT:
-            break;
-        }
+//        switch (exc.exc_type)
+//        {
+//        case EXC_BAD_ACCESS:
+//            break;
+//        case EXC_BAD_INSTRUCTION:
+//            break;
+//        case EXC_ARITHMETIC:
+//            break;
+//        case EXC_EMULATION:
+//            break;
+//        case EXC_SOFTWARE:
+//            break;
+//        case EXC_BREAKPOINT:
+//            break;
+//        case EXC_SYSCALL:
+//            break;
+//        case EXC_MACH_SYSCALL:
+//            break;
+//        case EXC_RPC_ALERT:
+//            break;
+//        }
     }
     return handled;
 }
@@ -658,27 +668,6 @@ MachThread::DisableHardwareWatchpoint (const DNBBreakpoint *wp)
     return false;
 }
 
-
-void
-MachThread::NotifyBreakpointChanged (const DNBBreakpoint *bp)
-{
-    nub_break_t breakID = bp->GetID();
-    if (bp->IsEnabled())
-    {
-        if (bp->Address() == GetPC())
-        {
-            SetCurrentBreakpoint(breakID);
-        }
-    }
-    else
-    {
-        if (CurrentBreakpoint() == breakID)
-        {
-            SetCurrentBreakpoint(INVALID_NUB_BREAK_ID);
-        }
-    }
-}
-
 bool
 MachThread::GetIdentifierInfo ()
 {