[lldb] Fix error message in IRInterpreter

[werat]

Summary

memory_read_error -> memory_write_error

[teemperor]

LGTM.

I think the Read/Write methods should return a Status instead of some out parameter, but that seems like a NFC follow-up refactoring (I can take care of that).

[teemperor]

I would be curious how you found that bug? I believe a lot of these errors are kinda impossible to reach in a normal test setup (I remember I tried writing some tests for this but can't remember finding a good way to get into all the different error branches in IRInterpreter).

[werat]

I was looking into the issue with SBValue::Persist (https://discord.com/channels/636084430946959380/636732809708306432/817370459284832297) and the logs and errors eventually led me here to IRInterpreter. And the incorrect error message I noticed just by accident :)

lldb/source/Expression/IRInterpreter.cpp

case Instruction::Load: {
       }
 
       lldb_private::Status write_error;
       execution_unit.WriteMemory(D, buffer.GetBytes(), buffer.GetByteSize(),
                                  write_error);
       if (!write_error.Success()) {
         LLDB_LOGF(log, "Couldn't write to a region on behalf of a LoadInst");
         error.SetErrorToGenericError();
-        error.SetErrorString(memory_read_error);
+        error.SetErrorString(memory_write_error);
         return false;
       }
 
       if (log) {
         LLDB_LOGF(log, "Interpreted a LoadInst");
         LLDB_LOGF(log, "  P : 0x%" PRIx64, P);
         LLDB_LOGF(log, "  R : 0x%" PRIx64, R);
         LLDB_LOGF(log, "  D : 0x%" PRIx64, D);