<rdar://problem/15172417>

Added two new GDB server packets to debugserver: "QSaveRegisterState" and "QRestoreRegiterState".

"QSaveRegisterState" makes the remote GDB server save all register values and it returns a save identifier as an unsigned integer. This packet can be used prior to running expressions to save all registers.

All registers can them we later restored with "QRestoreRegiterState:SAVEID" what SAVEID is the integer identifier that was returned from the call to QSaveRegisterState.

Cleaned up redundant code in lldb_private::Thread, lldb_private::ThreadPlanCallFunction.
Moved the lldb_private::Thread::RegisterCheckpoint into its own header file and it is now in the lldb_private namespace. Trimmed down the RegisterCheckpoint class to omit stuff that wasn't used (the stack ID).

Added a few new virtual methods to lldb_private::RegisterContext that allow subclasses to efficiently save/restore register states and changed the RegisterContextGDBRemote to take advantage of these new calls.

llvm-svn: 194621

1 files changed, 20 insertions, 0 deletions

diff --git a/lldb/tools/debugserver/source/DNBArch.h b/lldb/tools/debugserver/source/DNBArch.h
index 1c5c5b2db6f..e4f6bd2fada 100644
--- a/lldb/tools/debugserver/source/DNBArch.h
+++ b/lldb/tools/debugserver/source/DNBArch.h
@@ -58,10 +58,22 @@ public:
     static bool
     SetArchitecture (uint32_t cpu_type);
     
+    DNBArchProtocol () :
+        m_save_id(0)
+    {
+        
+    }
+    
+    virtual ~DNBArchProtocol ()
+    {
+        
+    }
     virtual bool            GetRegisterValue (int set, int reg, DNBRegisterValue *value) = 0;
     virtual bool            SetRegisterValue (int set, int reg, const DNBRegisterValue *value) = 0;
     virtual nub_size_t      GetRegisterContext (void *buf, nub_size_t buf_len) = 0;
     virtual nub_size_t      SetRegisterContext (const void *buf, nub_size_t buf_len) = 0;
+    virtual uint32_t        SaveRegisterState () = 0;
+    virtual bool            RestoreRegisterState (uint32_t save_id) = 0;
 
     virtual kern_return_t   GetRegisterState (int set, bool force) = 0;
     virtual kern_return_t   SetRegisterState (int set) = 0;
@@ -85,6 +97,11 @@ public:
 protected:
     friend class MachThread;
 
+    uint32_t                GetNextRegisterStateSaveID ()
+                            {
+                                return ++m_save_id;
+                            }
+
     enum
     {
         Trans_Pending = 0,      // Transaction is pending, and checkpoint state has been snapshotted.
@@ -94,6 +111,9 @@ protected:
     virtual bool StartTransForHWP() { return true; }
     virtual bool RollbackTransForHWP() { return true; }
     virtual bool FinishTransForHWP() { return true; }
+    
+    uint32_t m_save_id;         // An always incrementing integer ID used with SaveRegisterState/RestoreRegisterState
+
 };