[lldb] on s390x fix override issue

[kwk]

Summary

This fixes an override issue by marking a function as const so that the
signature maps to the signature of the function in the base class.

The overridden function was changed in revision 7fa7b81bcbd040d036f9a4155486ccebc3c13be7 by @omjavaid .

This is the original error:

In file included from /root/llvm/lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux_s390x.cpp:11:
/root/llvm/lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux_s390x.h:79:10: error: 'size_t lldb_private::process_linux::NativeRegisterContextLinux_s390x::GetGPRSize()' marked 'override', but does not override
   79 |   size_t GetGPRSize() override { return sizeof(m_regs); }
      |          ^~~~~~~~~~

[serge-sans-paille]

Looks obviously good to me.

[serge-sans-paille]

Possible followup: shouldn't all the other Get* be flagged as const too?

[kwk]

In D83580#2144871, @serge-sans-paille wrote:

Possible followup: shouldn't all the other Get* be flagged as const too?

Thank you @serge-sans-paille . You're right but I'm unsure if all getters are actually const or not. And I think one needs to figure this out for all overrides as well. And right now I don't want to break another arch ;)

lldb/source/Plugins/Process/Linux/NativeRegisterContextLinux_s390x.h

protected:
 
   Status WriteGPR() override;
 
   Status ReadFPR() override;
 
   Status WriteFPR() override;
 
   void *GetGPRBuffer() override { return &m_regs; }
-  size_t GetGPRSize() override { return sizeof(m_regs); }
+  size_t GetGPRSize() const override { return sizeof(m_regs); }
   void *GetFPRBuffer() override { return &m_fp_regs; }
   size_t GetFPRSize() override { return sizeof(m_fp_regs); }
 
 private:
   // Info about register ranges.
   struct RegInfo {
     uint32_t num_registers;
     uint32_t num_gpr_registers;