Report the actual user register count from NativeRegisterContextLinux_x86_64

[tberghammer]

Summary

Report the actual user register count from NativeRegisterContextLinux_x86_64

This change have effect when the AVX registers aren't available with reporting the count of user registers without them.

source/Plugins/Process/Linux/NativeRegisterContextLinux_x86_64.h

public:
         NativeRegisterContextLinux_x86_64 (NativeThreadProtocol &native_thread, uint32_t concrete_frame_idx, RegisterInfoInterface *reg_info_interface_p);
 
         uint32_t
         GetRegisterSetCount () const override;
 
         const RegisterSet *
         GetRegisterSet (uint32_t set_index) const override;
 
+        uint32_t
+        GetUserRegisterCount() const override;
+
         Error
         ReadRegister (const RegisterInfo *reg_info, RegisterValue &reg_value) override;
 
         Error
         WriteRegister (const RegisterInfo *reg_info, const RegisterValue &reg_value) override;
 
         Error
         ReadAllRegisterValues (lldb::DataBufferSP &data_sp) override;

source/Plugins/Process/Linux/NativeRegisterContextLinux_x86_64.cpp

NativeRegisterContextLinux_x86_64::GetRegisterSetCount () const
     {
         if (IsRegisterSetAvailable (set_index))
             ++sets;
     }
 
     return sets;
 }
 
+uint32_t
+NativeRegisterContextLinux_x86_64::GetUserRegisterCount() const
+{
+    uint32_t count = 0;
+    for (uint32_t set_index = 0; set_index < k_num_register_sets; ++set_index)
+    {
+        const lldb_private::RegisterSet* set = GetRegisterSet(set_index);
+        if (set)
+            count += set->num_registers;
+    }
+    return count;
+}
+
 const lldb_private::RegisterSet *
 NativeRegisterContextLinux_x86_64::GetRegisterSet (uint32_t set_index) const
 {
     if (!IsRegisterSetAvailable (set_index))
         return nullptr;
 
     switch (GetRegisterInfoInterface ().GetTargetArchitecture ().GetMachine ())
     {