[CMake] Use LLVM_COMMON_CMAKE_UTILS in runtimes just for clarity

In D116472 we created conditionally defined variables for the tools to
unbreak the legacy build where they are in `llvm/tools`.

The runtimes are not tools, so that flexibility doesn't matter. Still,
it might be nice to define (unconditionally) and use the variable for
the runtimes simply to make the code a bit clearer and document what is
going on.

Also, consistently put project dirs at the beginning, not end of `CMAKE_MODULE_PATH`. This ensures they will properly shadow similarly named stuff that happens to be later on the path.

Reviewed By: mstorsjo, #libunwind, #libc, #libc_abi, ldionne

Differential Revision: https://reviews.llvm.org/D116477

compiler-rt/CMakeLists.txt

@@ -12,12 +12,14 @@ if (CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR OR COMPILER_RT_STANDALONE
   set_property(GLOBAL PROPERTY USE_FOLDERS ON)
 endif()
 
+set(LLVM_COMMON_CMAKE_UTILS "${CMAKE_CURRENT_SOURCE_DIR}/../cmake")
+
 # Add path for custom compiler-rt modules.
 list(INSERT CMAKE_MODULE_PATH 0
   "${CMAKE_CURRENT_SOURCE_DIR}/cmake"
   "${CMAKE_CURRENT_SOURCE_DIR}/cmake/Modules"
-  "${CMAKE_CURRENT_SOURCE_DIR}/../cmake"
-  "${CMAKE_CURRENT_SOURCE_DIR}/../cmake/Modules"
+  "${LLVM_COMMON_CMAKE_UTILS}"
+  "${LLVM_COMMON_CMAKE_UTILS}/Modules"
   )
 
 if(CMAKE_CONFIGURATION_TYPES)

compiler-rt/lib/builtins/CMakeLists.txt

@@ -9,11 +9,19 @@ if (CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
   project(CompilerRTBuiltins C ASM)
   set(COMPILER_RT_STANDALONE_BUILD TRUE)
   set(COMPILER_RT_BUILTINS_STANDALONE_BUILD TRUE)
+
+  set(COMPILER_RT_SOURCE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/../..")
+
+  set(LLVM_COMMON_CMAKE_UTILS "${COMPILER_RT_SOURCE_DIR}/../cmake")
+
+  # Add path for custom modules
   list(INSERT CMAKE_MODULE_PATH 0
-    "${CMAKE_SOURCE_DIR}/../../cmake"
-    "${CMAKE_SOURCE_DIR}/../../cmake/Modules"
-    "${CMAKE_SOURCE_DIR}/../../../cmake"
-    "${CMAKE_SOURCE_DIR}/../../../cmake/Modules")
+    "${COMPILER_RT_SOURCE_DIR}/cmake"
+    "${COMPILER_RT_SOURCE_DIR}/cmake/Modules"
+    "${LLVM_COMMON_CMAKE_UTILS}"
+    "${LLVM_COMMON_CMAKE_UTILS}/Modules"
+    )
+
   include(base-config-ix)
   include(CompilerRTUtils)
 

libcxx/CMakeLists.txt

@@ -10,13 +10,14 @@ endif()
 #===============================================================================
 cmake_minimum_required(VERSION 3.13.4)
 
+set(LLVM_COMMON_CMAKE_UTILS "${CMAKE_CURRENT_SOURCE_DIR}/../cmake")
+
 # Add path for custom modules
-set(CMAKE_MODULE_PATH
+list(INSERT CMAKE_MODULE_PATH 0
   "${CMAKE_CURRENT_SOURCE_DIR}/cmake"
   "${CMAKE_CURRENT_SOURCE_DIR}/cmake/Modules"
-  "${CMAKE_CURRENT_SOURCE_DIR}/../cmake"
-  "${CMAKE_CURRENT_SOURCE_DIR}/../cmake/Modules"
-  ${CMAKE_MODULE_PATH}
+  "${LLVM_COMMON_CMAKE_UTILS}"
+  "${LLVM_COMMON_CMAKE_UTILS}/Modules"
   )
 
 set(CMAKE_FOLDER "libc++")

libcxxabi/CMakeLists.txt

@@ -10,13 +10,14 @@ endif()
 
 cmake_minimum_required(VERSION 3.13.4)
 
+set(LLVM_COMMON_CMAKE_UTILS "${CMAKE_CURRENT_SOURCE_DIR}/../cmake")
+
 # Add path for custom modules
-set(CMAKE_MODULE_PATH
+list(INSERT CMAKE_MODULE_PATH 0
   "${CMAKE_CURRENT_SOURCE_DIR}/cmake"
   "${CMAKE_CURRENT_SOURCE_DIR}/cmake/Modules"
-  "${CMAKE_CURRENT_SOURCE_DIR}/../cmake"
-  "${CMAKE_CURRENT_SOURCE_DIR}/../cmake/Modules"
-  ${CMAKE_MODULE_PATH}
+  "${LLVM_COMMON_CMAKE_UTILS}"
+  "${LLVM_COMMON_CMAKE_UTILS}/Modules"
   )
 
 set(CMAKE_FOLDER "libc++")

libunwind/CMakeLists.txt

@@ -8,13 +8,14 @@ endif()
 
 cmake_minimum_required(VERSION 3.13.4)
 
+set(LLVM_COMMON_CMAKE_UTILS "${CMAKE_CURRENT_SOURCE_DIR}/../cmake")
+
 # Add path for custom modules
-set(CMAKE_MODULE_PATH
+list(INSERT CMAKE_MODULE_PATH 0
   "${CMAKE_CURRENT_SOURCE_DIR}/cmake"
   "${CMAKE_CURRENT_SOURCE_DIR}/cmake/Modules"
-  "${CMAKE_CURRENT_SOURCE_DIR}/../cmake"
-  "${CMAKE_CURRENT_SOURCE_DIR}/../cmake/Modules"
-  ${CMAKE_MODULE_PATH}
+  "${LLVM_COMMON_CMAKE_UTILS}"
+  "${LLVM_COMMON_CMAKE_UTILS}/Modules"
   )
 
 set(LIBUNWIND_SOURCE_DIR  ${CMAKE_CURRENT_SOURCE_DIR})

runtimes/CMakeLists.txt

@@ -28,12 +28,14 @@ endfunction()
 find_package(LLVM PATHS "${LLVM_BINARY_DIR}" NO_DEFAULT_PATH NO_CMAKE_FIND_ROOT_PATH)
 find_package(Clang PATHS "${LLVM_BINARY_DIR}" NO_DEFAULT_PATH NO_CMAKE_FIND_ROOT_PATH)
 
+set(LLVM_COMMON_CMAKE_UTILS "${CMAKE_CURRENT_SOURCE_DIR}/../cmake")
+
 # Add path for custom and the LLVM build's modules to the CMake module path.
 list(INSERT CMAKE_MODULE_PATH 0
   "${CMAKE_CURRENT_SOURCE_DIR}/cmake"
   "${CMAKE_CURRENT_SOURCE_DIR}/cmake/modules"
-  "${CMAKE_CURRENT_SOURCE_DIR}/../cmake"
-  "${CMAKE_CURRENT_SOURCE_DIR}/../cmake/Modules"
+  "${LLVM_COMMON_CMAKE_UTILS}"
+  "${LLVM_COMMON_CMAKE_UTILS}/Modules"
   "${CMAKE_CURRENT_SOURCE_DIR}/../llvm/cmake"
   "${CMAKE_CURRENT_SOURCE_DIR}/../llvm/cmake/modules"
 )