[llvm] [CAS] LLVM_ENABLE_ONDISK_CAS requires `flock` on UNIX (PR #159207)

[Steven Wu via llvm-commits]

https://github.com/cachemeifyoucan updated https://github.com/llvm/llvm-project/pull/159207

>From 900c71faab152724717eb7cca574720d0f7b0396 Mon Sep 17 00:00:00 2001
From: Steven Wu <stevenwu at apple.com>
Date: Tue, 16 Sep 2025 15:37:41 -0700
Subject: [PATCH 1/2] =?UTF-8?q?[=F0=9D=98=80=F0=9D=97=BD=F0=9D=97=BF]=20in?=
 =?UTF-8?q?itial=20version?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Created using spr 1.3.6
---
 llvm/CMakeLists.txt                        | 7 -------
 llvm/cmake/modules/HandleLLVMOptions.cmake | 8 ++++++++
 2 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/llvm/CMakeLists.txt b/llvm/CMakeLists.txt
index c63d855ea289f..b98192968a3ab 100644
--- a/llvm/CMakeLists.txt
+++ b/llvm/CMakeLists.txt
@@ -879,13 +879,6 @@ option (LLVM_ENABLE_OCAMLDOC "Build OCaml bindings documentation." ON)
 option (LLVM_ENABLE_BINDINGS "Build bindings." ON)
 option (LLVM_ENABLE_TELEMETRY "Enable the telemetry library. If set to OFF, library cannot be enabled after build (eg., at runtime)" ON)
 
-set(LLVM_ENABLE_ONDISK_CAS_default ON)
-if(CMAKE_SIZEOF_VOID_P LESS 8 OR "${CMAKE_SYSTEM_NAME}" MATCHES SunOS)
-  # Build OnDiskCAS by default only on 64 bit machine that is not Solaris.
-  set(LLVM_ENABLE_ONDISK_CAS_default OFF)
-endif()
-option(LLVM_ENABLE_ONDISK_CAS "Build OnDiskCAS." ${LLVM_ENABLE_ONDISK_CAS_default})
-
 set(LLVM_INSTALL_DOXYGEN_HTML_DIR "${CMAKE_INSTALL_DOCDIR}/llvm/doxygen-html"
     CACHE STRING "Doxygen-generated HTML documentation install directory")
 set(LLVM_INSTALL_OCAMLDOC_HTML_DIR "${CMAKE_INSTALL_DOCDIR}/llvm/ocaml-html"
diff --git a/llvm/cmake/modules/HandleLLVMOptions.cmake b/llvm/cmake/modules/HandleLLVMOptions.cmake
index 4f227e8b1069a..b3e8093713647 100644
--- a/llvm/cmake/modules/HandleLLVMOptions.cmake
+++ b/llvm/cmake/modules/HandleLLVMOptions.cmake
@@ -1479,3 +1479,11 @@ if(LLVM_ENABLE_LLVM_LIBC)
     message(WARNING "Unable to link against LLVM libc. LLVM will be built without linking against the LLVM libc overlay.")
   endif()
 endif()
+
+check_symbol_exists(flock "sys/file.h" HAVE_FLOCK)
+set(LLVM_ENABLE_ONDISK_CAS_default OFF)
+if(HAVE_FLOCK OR LLVM_ON_WIN32)
+  # LLVM ONDisk CAS currently requires flock on Unix.
+  set(LLVM_ENABLE_ONDISK_CAS_default ON)
+endif()
+option(LLVM_ENABLE_ONDISK_CAS "Build OnDiskCAS." ${LLVM_ENABLE_ONDISK_CAS_default})

>From 9e273584fd6ce3522047315b7ef92d210204ebc6 Mon Sep 17 00:00:00 2001
From: Steven Wu <stevenwu at apple.com>
Date: Tue, 16 Sep 2025 15:38:52 -0700
Subject: [PATCH 2/2] Fix a typo in comment

Created using spr 1.3.6
---
 llvm/cmake/modules/HandleLLVMOptions.cmake | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/llvm/cmake/modules/HandleLLVMOptions.cmake b/llvm/cmake/modules/HandleLLVMOptions.cmake
index b3e8093713647..185e78df1f5ba 100644
--- a/llvm/cmake/modules/HandleLLVMOptions.cmake
+++ b/llvm/cmake/modules/HandleLLVMOptions.cmake
@@ -1483,7 +1483,7 @@ endif()
 check_symbol_exists(flock "sys/file.h" HAVE_FLOCK)
 set(LLVM_ENABLE_ONDISK_CAS_default OFF)
 if(HAVE_FLOCK OR LLVM_ON_WIN32)
-  # LLVM ONDisk CAS currently requires flock on Unix.
+  # LLVM OnDisk CAS currently requires flock on Unix.
   set(LLVM_ENABLE_ONDISK_CAS_default ON)
 endif()
 option(LLVM_ENABLE_ONDISK_CAS "Build OnDiskCAS." ${LLVM_ENABLE_ONDISK_CAS_default})