[llvm] [yaml2obj][MachO] Fix crash from integer underflow with invalid cmdsize (PR #165924)

[James Henderson via llvm-commits]

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@@ -287,9 +300,18 @@ void MachOWriter::writeLoadCommands(raw_ostream &OS) {
     // specified test cases.
     // Prevent integer underflow if BytesWritten exceeds cmdsize.
     if (BytesWritten > LC.Data.load_command_data.cmdsize) {
-      errs() << "warning: load command " << LC.Data.load_command_data.cmd
-             << " cmdsize too small (" << LC.Data.load_command_data.cmdsize
-             << " bytes) for actual size (" << BytesWritten << " bytes)\n";
+      const char *name = getLoadCommandName(LC.Data.load_command_data.cmd);
+      if (name)
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jh7370 wrote:

I don't like the duplicated code in the two halves of the if. Could you refactor it, to not duplicate the majority of the warning message printing?

https://github.com/llvm/llvm-project/pull/165924