Add support for the 'G' packet not being implemented or returning an error.

If we are asked to restore all register values, we need to fall back to 
restoring each register one by one.

llvm-svn: 131398

2 files changed, 44 insertions, 7 deletions

diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteRegisterContext.cpp b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteRegisterContext.cpp
index 8c39aa43842..306b427048b 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteRegisterContext.cpp
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteRegisterContext.cpp
@@ -230,13 +230,13 @@ GDBRemoteRegisterContext::WriteRegister (const RegisterInfo *reg_info,
 {
     DataExtractor data;
     if (value.GetData (data))
-        return WriteRegisterBytes (reg_info, value, data, 0);
+        return WriteRegisterBytes (reg_info, data, 0);
     return false;
 }
 
 
 bool
-GDBRemoteRegisterContext::WriteRegisterBytes (const lldb_private::RegisterInfo *reg_info, const RegisterValue &value, DataExtractor &data, uint32_t data_offset)
+GDBRemoteRegisterContext::WriteRegisterBytes (const lldb_private::RegisterInfo *reg_info, DataExtractor &data, uint32_t data_offset)
 {
     GDBRemoteCommunicationClient &gdb_comm (GetGDBProcess().GetGDBRemote());
 // FIXME: This check isn't right because IsRunning checks the Public state, but this
@@ -386,13 +386,51 @@ GDBRemoteRegisterContext::WriteAllRegisterValues (const lldb::DataBufferSP &data
         const bool thread_suffix_supported = gdb_comm.GetThreadSuffixSupported();
         if (thread_suffix_supported || GetGDBProcess().GetGDBRemote().SetCurrentThread(m_thread.GetID()))
         {
-            if (gdb_comm.SendPacketAndWaitForResponse((const char *)data_sp->GetBytes(), 
-                                                      data_sp->GetByteSize(), 
-                                                      response, 
-                                                      false))
+            // The data_sp contains the entire G response packet including the
+            // G, and if the thread suffix is supported, it has the thread suffix
+            // as well.
+            const char *G_packet = (const char *)data_sp->GetBytes();
+            size_t G_packet_len = data_sp->GetByteSize();
+            if (gdb_comm.SendPacketAndWaitForResponse (G_packet, 
+                                                       G_packet_len, 
+                                                       response, 
+                                                       false))
             {
                 if (response.IsOKResponse())
                     return true;
+                else if (response.IsErrorResponse())
+                {
+                    uint32_t num_restored = 0;
+                    // We need to manually go through all of the registers and
+                    // restore them manually
+                    DataExtractor data (G_packet + 1,   // Skip the leading 'G'
+                                        G_packet_len - 1,
+                                        m_reg_data.GetByteOrder(),
+                                        m_reg_data.GetAddressByteSize());
+
+                    //ReadRegisterBytes (const RegisterInfo *reg_info, RegisterValue &value, DataExtractor &data)
+                    const RegisterInfo *reg_info;
+                    for (uint32_t reg_idx=0; (reg_info = GetRegisterInfoAtIndex (reg_idx)) != NULL; ++reg_idx)
+                    {
+                        const uint32_t reg = reg_info->kinds[eRegisterKindLLDB];
+                        
+                        // Only write down the registers that need to be written 
+                        // if we are going to be doing registers individually.
+                        bool write_reg = true;
+                        const uint32_t reg_byte_offset = reg_info->byte_offset;
+                        const uint32_t reg_byte_size = reg_info->byte_size;
+                        if (m_reg_valid[reg])
+                        {
+                            const uint8_t *current_src = m_reg_data.PeekData(reg_byte_offset, reg_byte_size);
+                            const uint8_t *restore_src = data.PeekData(reg_byte_offset, reg_byte_size);
+                            if (current_src && restore_src)
+                                write_reg = memcmp (current_src, restore_src, reg_byte_size) != 0;
+                        }
+                        if (WriteRegisterBytes(reg_info, data, reg_byte_offset))
+                            ++num_restored;
+                    }
+                    return num_restored > 0;
+                }
             }
         }
     }
diff --git a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteRegisterContext.h b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteRegisterContext.h
index 315284780a4..43a3a10142e 100644
--- a/lldb/source/Plugins/Process/gdb-remote/GDBRemoteRegisterContext.h
+++ b/lldb/source/Plugins/Process/gdb-remote/GDBRemoteRegisterContext.h
@@ -232,7 +232,6 @@ protected:
 
     bool
     WriteRegisterBytes (const lldb_private::RegisterInfo *reg_info,
-                        const lldb_private::RegisterValue &value, 
                         lldb_private::DataExtractor &data, 
                         uint32_t data_offset);