[llvm-branch-commits] [libcxx] release/20.x: [libcxx] [test] Fix restoring LLVM_DIR and Clang_DIR (#132838) (PR #133153)

[via llvm-branch-commits]

https://github.com/llvmbot created https://github.com/llvm/llvm-project/pull/133153

Backport 51bceb46f8eeb7c3d060387be315ca41855933c2

Requested by: @mstorsjo

>From b6cc484e46b8d837b5256a994c73e1530bbb807d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Storsj=C3=B6?= <martin at martin.st>
Date: Wed, 26 Mar 2025 22:13:28 +0200
Subject: [PATCH] [libcxx] [test] Fix restoring LLVM_DIR and Clang_DIR
 (#132838)

In 664f345cd53d1f624d94f9889a1c9fff803e3391, a fix was introduced,
attempting to restore LLVM_DIR and Clang_DIR after doing
find_package(Clang).

However, 6775285e7695f2d45cf455f5d31b2c9fa9362d3d added a return if the
clangTidy target wasn't found. If this is hit, we don't restore LLVM_DIR
and Clang_DIR, which causes strange effects if CMake is rerun a second
time.

Move the code for restoring LLVM_DIR and Clang_DIR to directly after the
find_package calls, to make sure they are restored, regardless of the
find_package outcome.

(cherry picked from commit 51bceb46f8eeb7c3d060387be315ca41855933c2)
---
 libcxx/test/tools/clang_tidy_checks/CMakeLists.txt | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/libcxx/test/tools/clang_tidy_checks/CMakeLists.txt b/libcxx/test/tools/clang_tidy_checks/CMakeLists.txt
index 0f8f0e8864d0f..da045fac92ce4 100644
--- a/libcxx/test/tools/clang_tidy_checks/CMakeLists.txt
+++ b/libcxx/test/tools/clang_tidy_checks/CMakeLists.txt
@@ -8,6 +8,10 @@ set(Clang_DIR_SAVE ${Clang_DIR})
 # versions must match. Otherwise there likely will be ODR-violations. This had
 # led to crashes and incorrect output of the clang-tidy based checks.
 find_package(Clang ${CMAKE_CXX_COMPILER_VERSION})
+
+set(LLVM_DIR "${LLVM_DIR_SAVE}" CACHE PATH "The directory containing a CMake configuration file for LLVM." FORCE)
+set(Clang_DIR "${Clang_DIR_SAVE}" CACHE PATH "The directory containing a CMake configuration file for Clang." FORCE)
+
 if(NOT Clang_FOUND)
   message(STATUS "Clang-tidy tests are disabled since the "
                  "Clang development package is unavailable.")
@@ -19,9 +23,6 @@ if(NOT TARGET clangTidy)
   return()
 endif()
 
-set(LLVM_DIR "${LLVM_DIR_SAVE}" CACHE PATH "The directory containing a CMake configuration file for LLVM." FORCE)
-set(Clang_DIR "${Clang_DIR_SAVE}" CACHE PATH "The directory containing a CMake configuration file for Clang." FORCE)
-
 message(STATUS "Found system-installed LLVM ${LLVM_PACKAGE_VERSION} with headers in ${LLVM_INCLUDE_DIRS}")
 
 set(CMAKE_CXX_STANDARD 20)