[lldb][llvm-lit] Enable internal shell for lldb test suite

[connieyzhu]

Testing in lit is currently inconsistent across different platforms, as many RUN line commands are written in a way that only works on POSIX-compliant shells. Lit has an internal shell implementation to ensure uniform execution of these commands that can be used regardless of platform. We should aim to turn on the internal shell for the lldb test suite to eliminate reliance on external shells.

The internal shell has missing capabilities that need to be addressed before doing so. Here is a list of the issues that block us from turning on the internal shell for lldb.

• [llvm-lit] lit internal shell does not support -e option for cat commands #102377
  [llvm-lit] No such file or directory error in lldb tests with lit internal shell #102696

[llvmbot]

@llvm/issue-subscribers-lldb

Author: Connie (connieyzhu)

Testing in lit is currently inconsistent across different platforms, as many RUN line commands are written in a way that only works on POSIX-compliant shells. Lit has an internal shell implementation to ensure uniform execution of these commands that can be used regardless of platform. We should aim to turn on the internal shell for the `lldb` test suite to eliminate reliance on external shells.

The internal shell has missing capabilities that need to be addressed before doing so. Here is a list of the issues that block us from turning on the internal shell for lldb.

• cat -e
• No such file or directory