[Lldb-commits] [lldb] [lldb] [ObjC runtime] Don't cast to signed when left shifting (PR #86605)

[Jason Molenda via lldb-commits]

================
@@ -3154,7 +3154,7 @@ 
AppleObjCRuntimeV2::TaggedPointerVendorExtended::GetClassDescriptor(
                             << m_objc_debug_taggedpointer_ext_payload_lshift) 
>>
                            m_objc_debug_taggedpointer_ext_payload_rshift);
   int64_t data_payload_signed =
-      ((int64_t)((int64_t)unobfuscated
+      ((int64_t)((uint64_t)unobfuscated
                  << m_objc_debug_taggedpointer_ext_payload_lshift) >>
----------------
jasonmolenda wrote:

e.g. ```
(lldb) p (-5LL <<60) >> 60
(long long) -5
```

if the bit slice we're pulling out has its high bit set, that'll shfit down and 
be sign extended.

https://github.com/llvm/llvm-project/pull/86605
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