[llvm] [lit] Update internal shell lexer to handle LLDB persistent vars. (PR #156125)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-testing-tools

Author: None (cmtice)

<details>
<summary>Changes</summary>

LLDB allows creation of 'persistent' variables, with names that start with '$'. The lit internal shell was escaping the '$', making it '\$', in some CHECK lines, which causes some LLDB tests to fail when using the lit internal shell.

This PR fixes that by having the lexer remove the escape on the '$'.

---
Full diff: https://github.com/llvm/llvm-project/pull/156125.diff


1 Files Affected:

- (modified) llvm/utils/lit/lit/ShUtil.py (+5) 


``````````diff
diff --git a/llvm/utils/lit/lit/ShUtil.py b/llvm/utils/lit/lit/ShUtil.py
index fa13167cad1be..ff151b1e29330 100644
--- a/llvm/utils/lit/lit/ShUtil.py
+++ b/llvm/utils/lit/lit/ShUtil.py
@@ -115,6 +115,11 @@ def lex_arg_quoted(self, delim):
             c = self.eat()
             if c == delim:
                 return str
+            # LLDB uses "$" at the start of global variable names; it should
+            # not be escaped nor dropped.
+            elif c == "\\" and self.look() == "$":
+                c = self.eat()
+                str += c
             elif c == "\\" and delim == '"':
                 # Inside a '"' quoted string, '\\' only escapes the quote
                 # character and backslash, otherwise it is preserved.

``````````

</details>


https://github.com/llvm/llvm-project/pull/156125