[lldb] [llvm] [lldb] Support disassembling RISC-V proprietary instructions (PR #145793)

[David Spickett via llvm-commits]

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@@ -304,6 +304,9 @@ Changes to LLDB
     stop reason = SIGSEGV: sent by tkill system call (sender pid=649752, uid=2667987)
   ```
 * ELF Cores can now have their siginfo structures inspected using `thread siginfo`.
+* Changed invalid disassembly to say <unknown> instead of being blank.
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DavidSpickett wrote:

I would rephrase it a bit, to be clearer:
* Disassembly of unknown instructions now produces "<unknown>" instead of nothing at all.

https://github.com/llvm/llvm-project/pull/145793