[lldb] Fix invalid shift operator overload in Scalar

[mamai]

Summary

This also fixes an infinite recursion between lldb_private::operator>> () and Scalar::operator>>= ().

[labath]

Scalar::operator<<= seems to do a m_integer <<= .... Will it suffer from the same recursion problem?

In any case, I think the implementations of both methods should use the same API (it doesn't matter which one if both work).

Also it would be super great if you could make a tiny test for this, say in unittests/Core/ScalarTest.cpp

[mamai]

Scalar::operator<<= works well as-is because it uses APInt &operator<<=(unsigned shiftAmt), whereas the right shift equivalent is not implemented. Should I add APInt &operator>>=, or should I change Scalar::operator<<= for consistency ?

[labath]

Ah, ok I understand what's going on now. I guess APInt operator >> probably does not exist because it would be ambiguous (arithmetic or bitwise shift?). Let's just leave this as it is now.

Could you add that test though?

[mamai]

Added a small unit test for scalar right shift operator, which invokes the >>= operator.

[labath]

That's perfect. Thanks for adding that test.

Do you have commit access, or shall I put this in?

[mamai]

I don't have commit access. It would be great if you can push it for me. Thanks !

[labath]

Committed as r260239.

source/Core/Scalar.cpp

         case e_uint:
         case e_slong:
         case e_ulong:
         case e_slonglong:
         case e_ulonglong:
              case e_sint128:
              case e_uint128:
              {
-                 m_integer >> *rhs.m_integer.getRawData();
+                 m_integer = m_integer.ashr(*(const uint_t *)rhs.m_integer.getRawData());
                  break;
              }
         }
         break;
     }
     return *this;
 }