[standalone-build] outsource, simplify and unify repetitive CMake code

[kwk]

Summary

See also this topic on discourse: https://discourse.llvm.org/t/an-opinionated-way-to-outsource-simplify-and-unify-repetitive-cmake-code-in-standalone-build-mode/67508

Rationale

This is an opinionated change for the standalone build mode CMake code.

The rationale behind this change is to unify the parts of standalone
builds that historically had to be kept in each and every project. With
the advent of the top-level cmake directory inside the LLVM source
tree, it is now possible to bundle the CMake instructions into a file,
aka cmake/Modules/StandaloneBuildHelpers.cmake, and include that file
in each project that wants to build in standalone-mode.

Historically the standalone build mode is used mostly by Linux
distributions. Certainly not every LLVM contributor cares about Linux
distributions. To reduce the frictions it makes even more sense to have
a unified place where to keep the specialities of building in standalone
mode.

Affected projects (so far)

This change brings the unified standalone build mode to the clang and
lld project.

Assumptions

One radical assumption for this change is that in order to build clang
or ldd in standalone mode, you have to first build the llvm subproject
and *install* it into any location. You can assist the build process to
find LLVM using find_package(LLVM) by specifying
-DCMAKE_PREFIX_PATH=${LLVM_INSTALL_DIR}/lib/cmake/llvm in the cmake
configuration process.
You have to build the `llvm subproject with utilies included and
installed
(-DLLVM_INCLUDE_UTILS:BOOL=ON and -DLLVM_INSTALL_UTILS:BOOL=ON. But
I'm sure that this is done most of the time anyways, no?

Don't build as you go: No more cross-project dependencies on LLVM utilties

Another assumption is that in standalone build mode it makes no sense to
build clang and try to build an LLVM utility binary like FileCheck if
that is missing. This only adds noise to the cmake files and creates an
indirect dependency on the LLVM utilities directory which doesn't exist
in the the clang source tarball. Therefore we go and search for

Don't silently turn off tests

Before this change, we would silently turn off tests if a binary like
FileCheck, count or not was missing. This is not only dangerous
but IMHO not helpful. If someone asks for tests by passing
-DLLVM_INCLUDE_TESTS=On we should error out at configure time because
we cannot fulfil this request when a binary is missing. This is exactly
what this tests does. If you want to check if an LLVM utility binary
exists and what the path to it is, you can call
get_llvm_utility_binary_path("FileCheck" "FileCheck_EXE") and it will
get the import location for the target, aka the path to the binary that
was found when we did find_package(LLVM).

NOTE: You can take a look at this small example project which shows you how importing of an installed project works: https://github.com/kwk/cmake-export-binary-example/blob/2b429fccef97eb93c1717ceddb27bbe0022339d2/project-b/CMakeLists.txt#L7-L10

Require external LIT in standalone mode

We also think that in standalone mode you always want to use an external
lit and not build it as you go. That's why the find_external_lit macro
checks if LLVM_EXTERNAL_LIT is set and the path exists. If one of
these conditions doesn't hold true, we error out.

TODO:

( ) make sure the correct binaries of FileCheck and count and not
get substituted in lit test files.
( ) get feedback on this change or just opinions
( ) extend usage to other projects like mlir, libomp and so on.
( ) more encapsulation in cmake/Modules/StandaloneBuildHelpers.cmake

[phosek]

clang/CMakeLists.txt

35

It's somewhat unusual to quote output variable names in our CMake files, I'd prefer to follow existing conventions for consistency.

cmake/Modules/StandaloneBuildHelpers.cmake

13–20

I'd omit this, I don't think it's necessary to restrict the usage of this module.

26–31

Do you know why is this needed or this just copy pasted from Clang? I'd consider dropping this altogether (ideally in a separate change).

46–47

This shouldn't be needed since you've already had to insert the module path manually.

62

We use 2 spaces for indentation in our CMake files.

83–110

Is there any reason to keep these two macros separate? Could we combine them?

lld/CMakeLists.txt

57

Where are these variables being used?

[kwk]

• Don't quote output variables
• Use 2 space indention in CMake files
• Make out_var optional for get_llvm_utility_binary_path
• Rename get_llvm_utility_binary_path -> require_llvm_utility_binary_path

[kwk]

Thank you @phosek for your review! I really appreciate it. I've addressed all of your comments. Could you give it another review?

clang/CMakeLists.txt

35

I obey to the consistency.

cmake/Modules/StandaloneBuildHelpers.cmake

13–20

I think restricting the usage makes it clear for what it is. And right now this CMake file does stuff just when you include it which not a good thing in terms of isolation. If you don't mind I'd like to keep this restriction and only remove it before this patch lands in a better shape. Okay?

26–31

Honestly, I started to move the CMake code from clang over to this file piece by piece once I found that the exact or similar formatted code existed in other projects like lld. But you caught me red-handed :).

This is the patch that introduced this particular section: e6d79ec0ebac350355c76d8132e9f1cce62e0cac. It is from 2013.

I'm not so long involved in the llvm project that I can give a solid answer to this but hasn't llvm-config been deprecated for building LLVM itself? If that is the case, I'm happy to remove this section from the clang/CMakeLists.txt in the first place in a separate patch.

46–47

I don't see what the one has to do with the other immediately. Maybe I'm a fool. The CMAKE_INCLUDE_CURRENT_DIR is for including C/C++ files and not CMake files so it doesn't matter what I have in my module path, no?. Here's a little example project I created to proof to myself that my assumption is really true: https://github.com/kwk/cmake-example-CMAKE_INCLUDE_CURRENT_DIR . Just run make once you've clone it. Then comment out this line to see the effect: include(EnableCurrentIncludeDir).

62

I've fixed the indention to use 2 spaces.

83–110

Yes, to both of your questions :) . Yes, I find it easier to read the files that include this file and use the functions and macros when they are separated. And yes, we could combine them to setup_external_lit or something alike. But for the course of this patch I'd like to keep them separated and do the merge later if you don't mind.

lld/CMakeLists.txt

57

They were not being used, yet. I forgot to make the second parameter of get_llvm_utility_binary_path an optional one. Now it is optional and you can omit the second parameter. I've also renamed the function to require_llvm_utility_binary_path to convey the importance that the utility exists through the name of the function.

Also, I'd like to refer to the TODO in this patch's description:

make sure the correct binaries of FileCheck and count and not

get substituted in lit test files.

I'm quite positive that lit will use the correct binaries because we've imported the targets but still I wanna be sure. Having said that, you should not need the path except for LLVM_TABLEGEN_EXE. That variable existed before and I worked my function around it to fit this usecase.

[kwk]

• Make require_llvm_utility_binary_path usable from a build-tree setup

[kwk]

• both, build tree and install method support find_package by setting different LLVM_CMAKE_DIR

clang/CMakeLists.txt

message(WARNING
       "using an older CMake will become an error. Please upgrade your CMake to "
       "at least 3.20.0 now to avoid issues in the future!")
   endif()
 endif()
 
 # Must go below project(..)
 include(GNUInstallDirs)
 
-if(CLANG_BUILT_STANDALONE)
-  set(CMAKE_CXX_STANDARD 17 CACHE STRING "C++ standard to conform to")
-  set(CMAKE_CXX_STANDARD_REQUIRED YES)
-  set(CMAKE_CXX_EXTENSIONS NO)
-
-  if(NOT MSVC_IDE)
-    set(LLVM_ENABLE_ASSERTIONS ${ENABLE_ASSERTIONS}
-      CACHE BOOL "Enable assertions")
-    # Assertions should follow llvm-config's.
-    mark_as_advanced(LLVM_ENABLE_ASSERTIONS)
-  endif()
-
-  find_package(LLVM REQUIRED HINTS "${LLVM_CMAKE_DIR}")
-  list(APPEND CMAKE_MODULE_PATH "${LLVM_DIR}")
-
-  # Turn into CACHE PATHs for overwritting
-  set(LLVM_INCLUDE_DIRS ${LLVM_INCLUDE_DIRS} CACHE PATH "Path to llvm/include and any other header dirs needed")
-  set(LLVM_BINARY_DIR "${LLVM_BINARY_DIR}" CACHE PATH "Path to LLVM build tree")
-  set(LLVM_MAIN_SRC_DIR "${CMAKE_CURRENT_SOURCE_DIR}/../llvm" CACHE PATH "Path to LLVM source tree")
-  set(LLVM_TOOLS_BINARY_DIR "${LLVM_TOOLS_BINARY_DIR}" CACHE PATH "Path to llvm/bin")
-  set(LLVM_LIBRARY_DIR "${LLVM_LIBRARY_DIR}" CACHE PATH "Path to llvm/lib")
+# Make sure that our source directory is on the current cmake module path so that
+# we can include cmake files from this directory.
+list(INSERT CMAKE_MODULE_PATH 0
+  "${CMAKE_CURRENT_SOURCE_DIR}/cmake/modules"
+  "${LLVM_COMMON_CMAKE_UTILS}/Modules"
+  )
 
-  find_program(LLVM_TABLEGEN_EXE "llvm-tblgen" ${LLVM_TOOLS_BINARY_DIR}
-    NO_DEFAULT_PATH)
+if(CLANG_BUILT_STANDALONE)
+  include(StandaloneBuildHelpers)
+  require_llvm_utility_binary_path("llvm-tblgen" LLVM_TABLEGEN_EXE)
 
   # They are used as destination of target generators.
   set(LLVM_RUNTIME_OUTPUT_INTDIR ${CMAKE_BINARY_DIR}/${CMAKE_CFG_INTDIR}/bin)
   set(LLVM_LIBRARY_OUTPUT_INTDIR ${CMAKE_BINARY_DIR}/${CMAKE_CFG_INTDIR}/lib${LLVM_LIBDIR_SUFFIX})
   if(WIN32 OR CYGWIN)
     # DLL platform -- put DLLs into bin.
     set(LLVM_SHLIB_OUTPUT_INTDIR ${LLVM_RUNTIME_OUTPUT_INTDIR})
   else()
if(CLANG_BUILT_STANDALONE)
 
   set( CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/bin )
   set( CMAKE_LIBRARY_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib${LLVM_LIBDIR_SUFFIX} )
   set( CMAKE_ARCHIVE_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR}/lib${LLVM_LIBDIR_SUFFIX} )
 
   if(LLVM_INCLUDE_TESTS)
     find_package(Python3 ${LLVM_MINIMUM_PYTHON_VERSION} REQUIRED
       COMPONENTS Interpreter)
+    find_external_lit()
+    set_lit_defaults()
+    require_llvm_utility_binary_path("FileCheck")
+    require_llvm_utility_binary_path("count")
+    require_llvm_utility_binary_path("not")
 
-    # Check prebuilt llvm/utils.
-    if(EXISTS ${LLVM_TOOLS_BINARY_DIR}/FileCheck${CMAKE_EXECUTABLE_SUFFIX}
-        AND EXISTS ${LLVM_TOOLS_BINARY_DIR}/count${CMAKE_EXECUTABLE_SUFFIX}
-        AND EXISTS ${LLVM_TOOLS_BINARY_DIR}/not${CMAKE_EXECUTABLE_SUFFIX})
-      set(LLVM_UTILS_PROVIDED ON)
-    endif()
-
-    # Seek installed Lit.
-    find_program(LLVM_LIT
-                 NAMES llvm-lit lit.py lit
-                 PATHS "${LLVM_MAIN_SRC_DIR}/utils/lit"
-                 DOC "Path to lit.py")
-
-    if(EXISTS ${LLVM_MAIN_SRC_DIR}/utils/lit/lit.py)
-      # Note: path not really used, except for checking if lit was found
-      if(EXISTS ${LLVM_MAIN_SRC_DIR}/utils/llvm-lit)
-        add_subdirectory(${LLVM_MAIN_SRC_DIR}/utils/llvm-lit utils/llvm-lit)
-      endif()
-      if(NOT LLVM_UTILS_PROVIDED)
-        add_subdirectory(${LLVM_MAIN_SRC_DIR}/utils/FileCheck utils/FileCheck)
-        add_subdirectory(${LLVM_MAIN_SRC_DIR}/utils/count utils/count)
-        add_subdirectory(${LLVM_MAIN_SRC_DIR}/utils/not utils/not)
-        set(LLVM_UTILS_PROVIDED ON)
-        set(CLANG_TEST_DEPS FileCheck count not)
-      endif()
-      set(UNITTEST_DIR ${LLVM_THIRD_PARTY_DIR}/unittest)
-      if(EXISTS ${UNITTEST_DIR}/googletest/include/gtest/gtest.h
-          AND NOT EXISTS ${LLVM_LIBRARY_DIR}/${CMAKE_STATIC_LIBRARY_PREFIX}gtest${CMAKE_STATIC_LIBRARY_SUFFIX}
-          AND EXISTS ${UNITTEST_DIR}/CMakeLists.txt)
-        add_subdirectory(${UNITTEST_DIR} third-party/unittest)
-      endif()
-    endif()
-
-    if(LLVM_LIT)
-      # Define the default arguments to use with 'lit', and an option for the user
-      # to override.
-      set(LIT_ARGS_DEFAULT "-sv")
-      if (MSVC OR XCODE)
-        set(LIT_ARGS_DEFAULT "${LIT_ARGS_DEFAULT} --no-progress-bar")
-      endif()
-      set(LLVM_LIT_ARGS "${LIT_ARGS_DEFAULT}" CACHE STRING "Default options for lit")
-
-      get_errc_messages(LLVM_LIT_ERRC_MESSAGES)
-
-      # On Win32 hosts, provide an option to specify the path to the GnuWin32 tools.
-      if( WIN32 AND NOT CYGWIN )
-        set(LLVM_LIT_TOOLS_DIR "" CACHE PATH "Path to GnuWin32 tools")
-      endif()
-    else()
-      set(LLVM_INCLUDE_TESTS OFF)
-    endif()
 
     umbrella_lit_testsuite_begin(check-all)
   endif() # LLVM_INCLUDE_TESTS
 endif() # standalone
 
-# Make sure that our source directory is on the current cmake module path so that
-# we can include cmake files from this directory.
-list(INSERT CMAKE_MODULE_PATH 0
-  "${CMAKE_CURRENT_SOURCE_DIR}/cmake/modules"
-  "${LLVM_COMMON_CMAKE_UTILS}/Modules"
-  )
-
 # This allows disabling clang's XML dependency even if LLVM finds libxml2.
 # By default, clang depends on libxml2 if LLVM does.
 option(CLANG_ENABLE_LIBXML2 "Whether libclang may depend on libxml2"
        ${LLVM_ENABLE_LIBXML2})
 
 if(CLANG_ENABLE_LIBXML2)
   # Don't look for libxml if we're using MSan, since uninstrumented third party
   # code may call MSan interceptors like strlen, leading to false positives.

cmake/Modules/StandaloneBuildHelpers.cmake

+# This file provides helper functions and macros for projects that can be built
+# in standalone mode which you often find in linux packaging situations.
+# We also noticed that most functions set a bunch of variables in the same way
+# by default, so we do this while including this file.
+
+include_guard()
+
+# WARNING: The functions in this file only makes sense when building in standalone mode.
+#          Therefore it raises a FATAL_ERROR if you're using it in some other
+#          context.
+# TODO: Add the XXX_STANDALONE check for anything that is missing here.
+if (NOT (CLANG_BUILT_STANDALONE
+         OR LLD_BUILT_STANDALONE
+         OR COMPILER_RT_STANDALONE_BUILD
+         OR OPENMP_STANDALONE_BUILD
+         OR MLIR_STANDALONE_BUILD
+         OR LLDB_BUILT_STANDALONE))
+  message(FATAL_ERROR "Make sure you build in standalone mode")
+endif()
+
+set(CMAKE_CXX_STANDARD 17 CACHE STRING "C++ standard to conform to")
+set(CMAKE_CXX_STANDARD_REQUIRED YES)
+set(CMAKE_CXX_EXTENSIONS NO)
+
+if(NOT MSVC_IDE)
+set(LLVM_ENABLE_ASSERTIONS ${ENABLE_ASSERTIONS}
+  CACHE BOOL "Enable assertions")
+# Assertions should follow llvm-config's.
+mark_as_advanced(LLVM_ENABLE_ASSERTIONS)
+endif()
+
+# NOTE: The reason to first run `find_package(LLVM)` is that all the imported
+#       executables in LLVMExports.cmake are checked for existence. This saves
+#       us from checking for them ourselves.
+find_package(LLVM REQUIRED HINTS "${LLVM_CMAKE_DIR}")
+list(APPEND CMAKE_MODULE_PATH "${LLVM_DIR}")
+
+# Turn into CACHE PATHs for overwritting
+set(LLVM_INCLUDE_DIRS ${LLVM_INCLUDE_DIRS} CACHE PATH "Path to llvm/include and any other header dirs needed")
+set(LLVM_BINARY_DIR "${LLVM_BINARY_DIR}" CACHE PATH "Path to LLVM build tree")
+set(LLVM_MAIN_SRC_DIR "${CMAKE_CURRENT_SOURCE_DIR}/../llvm" CACHE PATH "Path to LLVM source tree")
+set(LLVM_TOOLS_BINARY_DIR "${LLVM_TOOLS_BINARY_DIR}" CACHE PATH "Path to llvm/bin")
+set(LLVM_LIBRARY_DIR "${LLVM_LIBRARY_DIR}" CACHE PATH "Path to llvm/lib")
+
+# Automatically add the current source and build directories to the include path.
+set(CMAKE_INCLUDE_CURRENT_DIR ON)
+
+# This function tries to get the path to the installed utility binary.
+#
+# - utility: The utility's target name to look up (e.g. FileCheck). If it does
+#            not exist, or if the imported location points to non-existing file
+#            a FATAL_ERROR is raised.
+#
+# - (optional) out_var: The variable with this name is set in the caller's
+#                       scope to hold the path to the utility binary.
+#
+# NOTE: Check the add_llvm_utility macro in AddLLVM.cmake to find out about how
+#       utilities are added. They get added to a global list property
+#       LLVM_EXPORTS which ends up in a file LLVMExports.cmake that is
+#       installed with LLVM. Your utility target must be defined there.
+function(require_llvm_utility_binary_path utility)
+  # The target of the utility has to exist be it imported or from the build
+  # tree.
+  if (NOT TARGET ${utility})
+    message(FATAL_ERROR "The utility with the following target name does not exist: \"${utility}\".")
+  endif()
+
+  if (NOT IMPORTED ${utility})
+    message(FATAL_ERROR "We can only get the binary path to an imported target and this target is not imported: ${utility}")
+  endif()
+
+  set(_imploc IMPORTED_LOCATION_NOCONFIG)
+  # Based on the build type that the installed LLVM was built with,
+  # we pick the right import location.
+  if (LLVM_BUILD_TYPE STREQUAL "Release")
+    set(_imploc IMPORTED_LOCATION_RELEASE)
+  elseif (LLVM_BUILD_TYPE STREQUAL "Debug")
+    set(_imploc IMPORTED_LOCATION_DEBUG)
+  elseif (LLVM_BUILD_TYPE STREQUAL "RelWithDebInfo")
+    set(_imploc IMPORTED_LOCATION_RELWITHDEBINFO)
+  elseif (LLVM_BUILD_TYPE STREQUAL "MinSize")
+    set(_imploc IMPORTED_LOCATION_MINSIZE)
+  endif()
+  get_target_property(util_path "${utility}" ${_imploc})
+
+  if (NOT EXISTS ${util_path})
+    message(FATAL_ERROR "This file for the target '${utility}' does not exist: ${util_path}")
+  endif()
+
+  if (DEFINED ARGV1)
+    set(out_var ${ARGV1})
+    set(${out_var} "${util_path}" PARENT_SCOPE)
+  endif()
+endfunction()
+
+# The set_lit_defaults macro exists because the code existed in multiple
+# locations before.
+macro(set_lit_defaults)
+  set(LIT_ARGS_DEFAULT "-sv")
+  if (MSVC OR XCODE)
+    set(LIT_ARGS_DEFAULT "${LIT_ARGS_DEFAULT} --no-progress-bar")
+  endif()
+  set(LLVM_LIT_ARGS "${LIT_ARGS_DEFAULT}" CACHE STRING "Default options for lit")
+
+  get_errc_messages(LLVM_LIT_ERRC_MESSAGES)
+  set(LLVM_LIT_ERRC_MESSAGES ${LLVM_LIT_ERRC_MESSAGES})
+
+  # On Win32 hosts, provide an option to specify the path to the GnuWin32 tools.
+  if( WIN32 AND NOT CYGWIN )
+    set(LLVM_LIT_TOOLS_DIR "" CACHE PATH "Path to GnuWin32 tools")
+  endif()
+endmacro()
+
+# The find_external_lit macro ensured the variable LLVM_EXTERNAL_LIT is defined
+# and points to an existing file.
+macro(find_external_lit)
+  if (NOT DEFINED LLVM_EXTERNAL_LIT)
+    message(FATAL_ERROR "In standalone build mode you MUST configure with -DLLVM_EXTERNAL_LIT=... pointing to your lit binary")
+  endif()
+  if (NOT EXISTS ${LLVM_EXTERNAL_LIT})
+    message(FATAL_ERROR "Failed to find external lit at place pointed to by LLVM_EXTERNAL_LIT variable: ${LLVM_EXTERNAL_LIT}")
+  endif()
+endmacro()

lld/CMakeLists.txt

message(WARNING
       "using an older CMake will become an error. Please upgrade your CMake to "
       "at least 3.20.0 now to avoid issues in the future!")
   endif()
 endif()
 
 # Must go below project(..)
 include(GNUInstallDirs)
 
-if(LLD_BUILT_STANDALONE)
-  set(CMAKE_CXX_STANDARD 17 CACHE STRING "C++ standard to conform to")
-  set(CMAKE_CXX_STANDARD_REQUIRED YES)
-  set(CMAKE_CXX_EXTENSIONS NO)
-
-  set(CMAKE_INCLUDE_CURRENT_DIR ON)
-
-  find_package(LLVM REQUIRED HINTS "${LLVM_CMAKE_DIR}")
-  list(APPEND CMAKE_MODULE_PATH "${LLVM_DIR}")
-
-  # Turn into CACHE PATHs for overwritting
-  set(LLVM_INCLUDE_DIRS ${LLVM_INCLUDE_DIRS} CACHE PATH "Path to llvm/include and any other header dirs needed")
-  set(LLVM_BINARY_DIR "${LLVM_BINARY_DIR}" CACHE PATH "Path to LLVM build tree")
-  set(LLVM_MAIN_SRC_DIR "${CMAKE_CURRENT_SOURCE_DIR}/../llvm" CACHE PATH "Path to LLVM source tree")
+# Make sure that our source directory is on the current cmake module path so that
+# we can include cmake files from this directory.
+list(INSERT CMAKE_MODULE_PATH 0
+  "${CMAKE_CURRENT_SOURCE_DIR}/cmake/modules"
+  "${LLVM_COMMON_CMAKE_UTILS}/Modules"
+  )
 
-  find_program(LLVM_TABLEGEN_EXE "llvm-tblgen" ${LLVM_TOOLS_BINARY_DIR}
-    NO_DEFAULT_PATH)
+if(LLD_BUILT_STANDALONE)
+  include(StandaloneBuildHelpers)
+  require_llvm_utility_binary_path("llvm-tblgen" LLVM_TABLEGEN_EXE)
 
   # They are used as destination of target generators.
   set(LLVM_RUNTIME_OUTPUT_INTDIR ${CMAKE_BINARY_DIR}/${CMAKE_CFG_INTDIR}/bin)
   set(LLVM_LIBRARY_OUTPUT_INTDIR ${CMAKE_BINARY_DIR}/${CMAKE_CFG_INTDIR}/lib${LLVM_LIBDIR_SUFFIX})
 
   include(AddLLVM)
   include(TableGen)
   include(HandleLLVMOptions)
   include(GetErrcMessages)
   include(CheckAtomic)
 
   set(PACKAGE_VERSION "${LLVM_PACKAGE_VERSION}")
 
   include_directories(${LLVM_INCLUDE_DIRS})
   link_directories(${LLVM_LIBRARY_DIRS})
 
   if(LLVM_INCLUDE_TESTS)
     find_package(Python3 ${LLVM_MINIMUM_PYTHON_VERSION} REQUIRED
       COMPONENTS Interpreter)
+    find_external_lit()
+    set_lit_defaults()
+    require_llvm_utility_binary_path("FileCheck")
+    require_llvm_utility_binary_path("count")
+    require_llvm_utility_binary_path("not")
 
-    # Check prebuilt llvm/utils.
-    if(EXISTS ${LLVM_TOOLS_BINARY_DIR}/FileCheck${CMAKE_EXECUTABLE_SUFFIX}
-        AND EXISTS ${LLVM_TOOLS_BINARY_DIR}/not${CMAKE_EXECUTABLE_SUFFIX})
-      set(LLVM_UTILS_PROVIDED ON)
-    endif()
-
-    if(EXISTS ${LLVM_MAIN_SRC_DIR}/utils/lit/lit.py)
-      # Note: path not really used, except for checking if lit was found
-      set(LLVM_LIT ${LLVM_MAIN_SRC_DIR}/utils/lit/lit.py)
-      if(NOT LLVM_UTILS_PROVIDED)
-        add_subdirectory(${LLVM_MAIN_SRC_DIR}/utils/FileCheck utils/FileCheck)
-        add_subdirectory(${LLVM_MAIN_SRC_DIR}/utils/not utils/not)
-        set(LLVM_UTILS_PROVIDED ON)
-        set(LLD_TEST_DEPS FileCheck not)
-      endif()
-      set(UNITTEST_DIR ${LLVM_THIRD_PARTY_DIR}/unittest)
-      if(EXISTS ${UNITTEST_DIR}/googletest/include/gtest/gtest.h
-          AND NOT EXISTS ${LLVM_LIBRARY_DIR}/${CMAKE_STATIC_LIBRARY_PREFIX}gtest${CMAKE_STATIC_LIBRARY_SUFFIX}
-          AND EXISTS ${UNITTEST_DIR}/CMakeLists.txt)
-        add_subdirectory(${UNITTEST_DIR} third-party/unittest)
-      endif()
-    else()
-      # Seek installed Lit.
-      find_program(LLVM_LIT
-                   NAMES llvm-lit lit.py lit
-                   PATHS "${LLVM_MAIN_SRC_DIR}/utils/lit"
-                   DOC "Path to lit.py")
-    endif()
-
-    if(LLVM_LIT)
-      # Define the default arguments to use with 'lit', and an option for the user
-      # to override.
-      set(LIT_ARGS_DEFAULT "-sv")
-      if (MSVC OR XCODE)
-        set(LIT_ARGS_DEFAULT "${LIT_ARGS_DEFAULT} --no-progress-bar")
-      endif()
-      set(LLVM_LIT_ARGS "${LIT_ARGS_DEFAULT}" CACHE STRING "Default options for lit")
-
-      get_errc_messages(LLVM_LIT_ERRC_MESSAGES)
-
-      # On Win32 hosts, provide an option to specify the path to the GnuWin32 tools.
-      if(WIN32 AND NOT CYGWIN)
-        set(LLVM_LIT_TOOLS_DIR "" CACHE PATH "Path to GnuWin32 tools")
-      endif()
-    else()
-      set(LLVM_INCLUDE_TESTS OFF)
-    endif()
   endif()
 
   if(LLVM_HAVE_LIBXAR)
     set(XAR_LIB xar)
   endif()
 endif() # standalone
 
 set(LLD_TOOLS_INSTALL_DIR "${CMAKE_INSTALL_BINDIR}" CACHE PATH

 if (CMAKE_SOURCE_DIR STREQUAL CMAKE_BINARY_DIR)
   message(FATAL_ERROR "In-source builds are not allowed. CMake would overwrite "
 "the makefiles distributed with LLVM. Please create a directory and run cmake "
 "from there, passing the path to this source directory as the last argument. "
 "This process created the file `CMakeCache.txt' and the directory "
 "`CMakeFiles'. Please delete them.")
 endif()
 
-# Add path for custom modules.
-list(INSERT CMAKE_MODULE_PATH 0
-  "${LLD_SOURCE_DIR}/cmake/modules"
-  "${LLVM_COMMON_CMAKE_UTILS}/Modules"
-  )
-
 include(AddLLD)
 
 option(LLD_USE_VTUNE
        "Enable VTune user task tracking."
        OFF)
 if (LLD_USE_VTUNE)
   find_package(VTune)
   if (VTUNE_FOUND)