[llvm] [lit] Prevent "lld" from being substituted by LIT in llvm-driver tests (PR #191893)

[via llvm-commits]

https://github.com/zeroomega updated https://github.com/llvm/llvm-project/pull/191893

>From 3f2be0867502584dfd682ee6b08f11750f8cb850 Mon Sep 17 00:00:00 2001
From: Haowei Wu <haowei at google.com>
Date: Mon, 13 Apr 2026 14:33:47 -0700
Subject: [PATCH] [lit] Prevent "lld" from being substituted by LIT in
 llvm-driver tests

We are seeing test failures in "passthrough-lld.test" as LIT
substitutes the "ld.lld" string in the test file to the full
path to the lld. However, the "-flavor" flag does not expect
a full path. It just need a name of the linker so it fails.
This patch modifies the lld matching regex in the use_lld
function in llvm/utils/lit/lit/llvm/config.py. It prevents
LIT from substitute any lld tool strings that are not
standalone.
---
 llvm/utils/lit/lit/llvm/config.py | 29 +++++++++++++++++------------
 1 file changed, 17 insertions(+), 12 deletions(-)

diff --git a/llvm/utils/lit/lit/llvm/config.py b/llvm/utils/lit/lit/llvm/config.py
index de70e80e60177..22bb15e449780 100644
--- a/llvm/utils/lit/lit/llvm/config.py
+++ b/llvm/utils/lit/lit/llvm/config.py
@@ -890,19 +890,24 @@ def use_lld(self, additional_tool_dirs=[], required=True, use_installed=False):
         )
 
         was_found = ld_lld and lld_link and ld64_lld and wasm_ld
+
+        lld_tools = [
+            ("ld.lld", ld_lld),
+            ("lld-link", lld_link),
+            ("ld64.lld", ld64_lld),
+            ("wasm-ld", wasm_ld),
+        ]
+
         tool_substitutions = []
-        if ld_lld:
-            tool_substitutions.append(ToolSubst(r"ld\.lld", command=ld_lld))
-            self.config.available_features.add("ld.lld")
-        if lld_link:
-            tool_substitutions.append(ToolSubst("lld-link", command=lld_link))
-            self.config.available_features.add("lld-link")
-        if ld64_lld:
-            tool_substitutions.append(ToolSubst(r"ld64\.lld", command=ld64_lld))
-            self.config.available_features.add("ld64.lld")
-        if wasm_ld:
-            tool_substitutions.append(ToolSubst("wasm-ld", command=wasm_ld))
-            self.config.available_features.add("wasm-ld")
+        for name, path in lld_tools:
+            if path:
+                escaped_name = name.replace(".", r"\.")
+                # Matches standalone name only, Avoid matching -flavor name, var=name
+                # cases.
+                regex = rf"(?<!-flavor\s)(?<!=)(?<![\.\-\^\/\\<])\b{escaped_name}\b(?![\.\-])"
+                tool_substitutions.append(ToolSubst(regex, command=path, verbatim=True))
+                self.config.available_features.add(name)
+
         self.add_tool_substitutions(tool_substitutions)
 
         return was_found