[compiler-rt] Reapply "[compiler-rt] Default to Lit's Internal Shell" (PR #168232)

[Aiden Grossman via llvm-commits]

https://github.com/boomanaiden154 created https://github.com/llvm/llvm-project/pull/168232

This reverts commit 8cc49fb99a4798f67b6b70fabfd584095d022e92.

This was causing failures on two specific buildbots that have since been fixed.

>From 9343918df08a0f044764fac4e7bbf61665c16114 Mon Sep 17 00:00:00 2001
From: Aiden Grossman <aidengrossman at google.com>
Date: Sat, 15 Nov 2025 19:41:07 +0000
Subject: [PATCH] Reapply "[compiler-rt] Default to Lit's Internal Shell"

This reverts commit 8cc49fb99a4798f67b6b70fabfd584095d022e92.

This was causing failures on two specific buildbots that have
since been fixed.
---
 compiler-rt/test/lit.common.cfg.py | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/compiler-rt/test/lit.common.cfg.py b/compiler-rt/test/lit.common.cfg.py
index 3f7dd8e402b78..0f0f87915bafe 100644
--- a/compiler-rt/test/lit.common.cfg.py
+++ b/compiler-rt/test/lit.common.cfg.py
@@ -113,6 +113,9 @@ def push_dynamic_library_lookup_path(config, new_path):
         config.environment[dynamic_library_lookup_var] = new_ld_library_path_64
 
 
+# TODO: Consolidate the logic for turning on the internal shell by default for all LLVM test suites.
+# See https://github.com/llvm/llvm-project/issues/106636 for more details.
+#
 # Choose between lit's internal shell pipeline runner and a real shell.  If
 # LIT_USE_INTERNAL_SHELL is in the environment, we use that as an override.
 use_lit_shell = os.environ.get("LIT_USE_INTERNAL_SHELL")
@@ -120,9 +123,8 @@ def push_dynamic_library_lookup_path(config, new_path):
     # 0 is external, "" is default, and everything else is internal.
     execute_external = use_lit_shell == "0"
 else:
-    # Otherwise we default to internal on Windows and external elsewhere, as
-    # bash on Windows is usually very slow.
-    execute_external = not sys.platform in ["win32"]
+    # Otherwise we default to internal everywhere.
+    execute_external = False
 
 # Allow expanding substitutions that are based on other substitutions
 config.recursiveExpansionLimit = 10