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

[via llvm-commits]

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

>From 715a2a79d7516aa381ff86db247cb3d19c9df650 Mon Sep 17 00:00:00 2001
From: Caroline Tice <cmtice at google.com>
Date: Thu, 28 Aug 2025 16:45:34 -0700
Subject: [PATCH] [lit] Update internal shell lexer to handle LLDB persistent
 vars.

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 '$'.
---
 llvm/utils/lit/lit/ShUtil.py | 5 +++++
 1 file changed, 5 insertions(+)

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.