<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.



git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@194621 91177308-0d34-0410-b5e6-96231b3b80d8

Author: Greg Clayton

include/lldb/Target/RegisterCheckpoint.h

@@ -0,0 +1,71 @@
+//===-- RegisterCheckpoint.h ------------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef liblldb_RegisterCheckpoint_h_
+#define liblldb_RegisterCheckpoint_h_
+
+#include "lldb/lldb-private.h"
+#include "lldb/Core/UserID.h"
+#include "lldb/Target/StackID.h"
+
+namespace lldb_private {
+
+    // Inherit from UserID in case pushing/popping all register values can be
+    // done using a 64 bit integer that holds a baton/cookie instead of actually
+    // having to read all register values into a buffer
+    class RegisterCheckpoint : public UserID
+    {
+    public:
+        
+        enum class Reason {
+            // An expression is about to be run on the thread if the protocol that
+            // talks to the debuggee supports checkpointing the registers using a
+            // push/pop then the UserID base class in the RegisterCheckpoint can
+            // be used to store the baton/cookie that refers to the remote saved
+            // state.
+            eExpression,
+            // The register checkpoint wants the raw register bytes, so they must
+            // be read into m_data_sp, or the save/restore checkpoint should fail.
+            eDataBackup
+        };
+        
+        RegisterCheckpoint(Reason reason) :
+            UserID(0),
+            m_data_sp (),
+            m_reason(reason)
+        {
+        }
+        
+        ~RegisterCheckpoint()
+        {
+        }
+        
+        lldb::DataBufferSP &
+        GetData()
+        {
+            return m_data_sp;
+        }
+        
+        const lldb::DataBufferSP &
+        GetData() const
+        {
+            return m_data_sp;
+        }
+        
+    protected:
+        lldb::DataBufferSP m_data_sp;
+        Reason m_reason;
+        
+        // Make RegisterCheckpointSP if you wish to share the data in this class.
+        DISALLOW_COPY_AND_ASSIGN(RegisterCheckpoint);
+    };
+    
+} // namespace lldb_private
+
+#endif  // liblldb_RegisterCheckpoint_h_

include/lldb/Target/RegisterContext.h

@@ -59,6 +59,18 @@ class RegisterContext :
     virtual bool
     WriteRegister (const RegisterInfo *reg_info, const RegisterValue &reg_value) = 0;
 
+    virtual bool
+    ReadAllRegisterValues (lldb::DataBufferSP &data_sp)
+    {
+        return false;
+    }
+    
+    virtual bool
+    WriteAllRegisterValues (const lldb::DataBufferSP &data_sp)
+    {
+        return false;
+    }
+
     // These two functions are used to implement "push" and "pop" of register states.  They are used primarily
     // for expression evaluation, where we need to push a new state (storing the old one in data_sp) and then
     // restoring the original state by passing the data_sp we got from ReadAllRegisters to WriteAllRegisterValues.
@@ -67,10 +79,10 @@ class RegisterContext :
     // so these API's should only be used when this behavior is needed.
 
     virtual bool
-    ReadAllRegisterValues (lldb::DataBufferSP &data_sp) = 0;
-
+    ReadAllRegisterValues (lldb_private::RegisterCheckpoint &reg_checkpoint);
+    
     virtual bool
-    WriteAllRegisterValues (const lldb::DataBufferSP &data_sp) = 0;
+    WriteAllRegisterValues (const lldb_private::RegisterCheckpoint &reg_checkpoint);
 
     bool
     CopyFromRegisterContext (lldb::RegisterContextSP context);

include/lldb/Target/Thread.h

@@ -17,6 +17,7 @@
 #include "lldb/Core/UserID.h"
 #include "lldb/Core/UserSettingsController.h"
 #include "lldb/Target/ExecutionContextScope.h"
+#include "lldb/Target/RegisterCheckpoint.h"
 #include "lldb/Target/StackFrameList.h"
 
 #define LLDB_THREAD_MAX_STOP_EXC_DATA 8
@@ -130,79 +131,12 @@ class Thread :
     DISALLOW_COPY_AND_ASSIGN (ThreadEventData);
     };
 
-    // TODO: You shouldn't just checkpoint the register state alone, so this should get
-    // moved to protected.  To do that ThreadStateCheckpoint needs to be returned as a token...
-    class RegisterCheckpoint
-    {
-    public:
-
-        RegisterCheckpoint() :
-            m_stack_id (),
-            m_data_sp ()
-        {
-        }
-
-        RegisterCheckpoint (const StackID &stack_id) :
-            m_stack_id (stack_id),
-            m_data_sp ()
-        {
-        }
-
-        ~RegisterCheckpoint()
-        {
-        }
-
-        const RegisterCheckpoint&
-        operator= (const RegisterCheckpoint &rhs)
-        {
-            if (this != &rhs)
-            {
-                this->m_stack_id = rhs.m_stack_id;
-                this->m_data_sp  = rhs.m_data_sp;
-            }
-            return *this;
-        }
-        
-        RegisterCheckpoint (const RegisterCheckpoint &rhs) :
-            m_stack_id (rhs.m_stack_id),
-            m_data_sp (rhs.m_data_sp)
-        {
-        }
-        
-        const StackID &
-        GetStackID()
-        {
-            return m_stack_id;
-        }
-
-        void
-        SetStackID (const StackID &stack_id)
-        {
-            m_stack_id = stack_id;
-        }
-
-        lldb::DataBufferSP &
-        GetData()
-        {
-            return m_data_sp;
-        }
-
-        const lldb::DataBufferSP &
-        GetData() const
-        {
-            return m_data_sp;
-        }
-
-    protected:
-        StackID m_stack_id;
-        lldb::DataBufferSP m_data_sp;
-    };
 
     struct ThreadStateCheckpoint
     {
         uint32_t           orig_stop_id;  // Dunno if I need this yet but it is an interesting bit of data.
         lldb::StopInfoSP   stop_info_sp;  // You have to restore the stop info or you might continue with the wrong signals.
-        RegisterCheckpoint register_backup;  // You need to restore the registers, of course...
+        lldb::RegisterCheckpointSP register_backup_sp;  // You need to restore the registers, of course...
         uint32_t           current_inlined_depth;
         lldb::addr_t       current_inlined_pc;
     };
@@ -1004,16 +938,6 @@ class Thread :
 
     typedef std::vector<lldb::ThreadPlanSP> plan_stack;
 
-    virtual bool
-    SaveFrameZeroState (RegisterCheckpoint &checkpoint);
-
-    virtual bool
-    RestoreSaveFrameZero (const RegisterCheckpoint &checkpoint);
-    
-    // register_data_sp must be a DataSP passed to ReadAllRegisterValues.
-    bool
-    ResetFrameZeroRegisters (lldb::DataBufferSP register_data_sp);
-
     virtual lldb_private::Unwind *
     GetUnwinder ();
 
@@ -1035,12 +959,6 @@ class Thread :
     lldb::StackFrameListSP
     GetStackFrameList ();
 
-    struct ThreadState
-    {
-        uint32_t           orig_stop_id;
-        lldb::StopInfoSP   stop_info_sp;
-        RegisterCheckpoint register_backup;
-    };
 
     //------------------------------------------------------------------
     // Classes that inherit from Process can see and modify these

include/lldb/Target/ThreadPlanCallFunction.h

@@ -163,7 +163,6 @@ class ThreadPlanCallFunction : public ThreadPlan
     Address                                         m_function_addr;
     Address                                         m_start_addr;
     lldb::addr_t                                    m_function_sp;
-    Thread::RegisterCheckpoint                      m_register_backup;
     lldb::ThreadPlanSP                              m_subplan_sp;
     LanguageRuntime                                *m_cxx_language_runtime;
     LanguageRuntime                                *m_objc_language_runtime;

include/lldb/lldb-forward.h

@@ -162,6 +162,7 @@ class   PythonDictionary;
 class   PythonInteger;
 class   PythonObject;
 class   PythonString;
+class   RegisterCheckpoint;
 class   RegisterContext;
 class   RegisterLocation;
 class   RegisterLocationList;
@@ -329,6 +330,7 @@ namespace lldb {
     typedef std::shared_ptr<lldb_private::ProcessLaunchInfo> ProcessLaunchInfoSP;
     typedef std::weak_ptr<lldb_private::Process> ProcessWP;
     typedef std::shared_ptr<lldb_private::Property> PropertySP;
+    typedef std::shared_ptr<lldb_private::RegisterCheckpoint> RegisterCheckpointSP;
     typedef std::shared_ptr<lldb_private::RegisterContext> RegisterContextSP;
     typedef std::shared_ptr<lldb_private::RegularExpression> RegularExpressionSP;
     typedef std::shared_ptr<lldb_private::ScriptInterpreterObject> ScriptInterpreterObjectSP;

lldb.xcodeproj/project.pbxproj

@@ -427,6 +427,7 @@
 		26A527C414E24F5F00F3A14A /* ThreadMachCore.h in Headers */ = {isa = PBXBuildFile; fileRef = 26A527C014E24F5F00F3A14A /* ThreadMachCore.h */; };
 		26A69C5F137A17A500262477 /* RegisterValue.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 26C6886E137880C400407EDF /* RegisterValue.cpp */; };
 		26A7A035135E6E4200FB369E /* OptionValue.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 26A7A034135E6E4200FB369E /* OptionValue.cpp */; };
+		26AB54121832DC3400EADFF3 /* RegisterCheckpoint.h in Headers */ = {isa = PBXBuildFile; fileRef = 26AB54111832DC3400EADFF3 /* RegisterCheckpoint.h */; };
 		26AB92121819D74600E63F3E /* DWARFDataExtractor.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 26AB92101819D74600E63F3E /* DWARFDataExtractor.cpp */; };
 		26AB92131819D74600E63F3E /* DWARFDataExtractor.h in Headers */ = {isa = PBXBuildFile; fileRef = 26AB92111819D74600E63F3E /* DWARFDataExtractor.h */; };
 		26ACEC2815E077AE00E94760 /* Property.h in Headers */ = {isa = PBXBuildFile; fileRef = 26ACEC2715E077AE00E94760 /* Property.h */; };
@@ -1090,6 +1091,7 @@
 		26A527C014E24F5F00F3A14A /* ThreadMachCore.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = ThreadMachCore.h; sourceTree = "<group>"; };
 		26A7A034135E6E4200FB369E /* OptionValue.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; name = OptionValue.cpp; path = source/Interpreter/OptionValue.cpp; sourceTree = "<group>"; };
 		26A7A036135E6E5300FB369E /* OptionValue.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; name = OptionValue.h; path = include/lldb/Interpreter/OptionValue.h; sourceTree = "<group>"; };
+		26AB54111832DC3400EADFF3 /* RegisterCheckpoint.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = RegisterCheckpoint.h; path = include/lldb/Target/RegisterCheckpoint.h; sourceTree = "<group>"; };
 		26AB92101819D74600E63F3E /* DWARFDataExtractor.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = DWARFDataExtractor.cpp; sourceTree = "<group>"; };
 		26AB92111819D74600E63F3E /* DWARFDataExtractor.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = DWARFDataExtractor.h; sourceTree = "<group>"; };
 		26ACEC2715E077AE00E94760 /* Property.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; name = Property.h; path = include/lldb/Interpreter/Property.h; sourceTree = "<group>"; };
@@ -3118,6 +3120,7 @@
 				264A43BD1320BCEB005B4096 /* Platform.cpp */,
 				26BC7DF310F1B81A00F91463 /* Process.h */,
 				26BC7F3610F1B90C00F91463 /* Process.cpp */,
+				26AB54111832DC3400EADFF3 /* RegisterCheckpoint.h */,
 				26BC7DF410F1B81A00F91463 /* RegisterContext.h */,
 				26BC7F3710F1B90C00F91463 /* RegisterContext.cpp */,
 				2618D78F1240115500F2B8FE /* SectionLoadList.h */,
@@ -3611,6 +3614,7 @@
 				AF254E32170CCC33007AE5C9 /* PlatformDarwinKernel.h in Headers */,
 				2694E99E14FC0BB30076DE67 /* PlatformFreeBSD.h in Headers */,
 				2694E9A514FC0BBD0076DE67 /* PlatformLinux.h in Headers */,
+				26AB54121832DC3400EADFF3 /* RegisterCheckpoint.h in Headers */,
 				26AB92131819D74600E63F3E /* DWARFDataExtractor.h in Headers */,
 				2663E379152BD1890091EC22 /* ReadWriteLock.h in Headers */,
 				945759681534941F005A9070 /* PlatformPOSIX.h in Headers */,