[lld][clang][cmake] Clean up a few things

[Ericson2314]

Summary

• If not using llvm-config, LLVM_MAIN_SRC_DIR now has a sane default

• LLVM_CONFIG_PATH will continue to work for LLD for back compat.

• More quoting of paths in an abundance of caution.

[nikic]

Not very familiar with cmake, but this looks reasonable to me.

clang/CMakeLists.txt

if(CLANG_BUILT_STANDALONE)
   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 ${LLVM_DIR})
+  list(APPEND CMAKE_MODULE_PATH "${LLVM_DIR}")
 
   # We can't check LLVM_CONFIG here, because find_package(LLVM ...) also sets
   # LLVM_CONFIG.
   if (NOT LLVM_CONFIG_FOUND)
     # Pull values from LLVMConfig.cmake.  We can drop this once the llvm-config
     # path is removed.
-    set(MAIN_INCLUDE_DIR ${LLVM_INCLUDE_DIR})
-    set(LLVM_OBJ_DIR ${LLVM_BINARY_DIR})
-    set(TOOLS_BINARY_DIR ${LLVM_TOOLS_BINARY_DIR})
-    set(LIBRARY_DIR ${LLVM_LIBRARY_DIR})
+    set(MAIN_INCLUDE_DIR "${LLVM_INCLUDE_DIR}")
+    set(LLVM_OBJ_DIR "${LLVM_BINARY_DIR}")
+    # N.B. this is just a default value, the CACHE PATHs below can be overriden.
+    set(MAIN_SRC_DIR "${CMAKE_CURRENT_SOURCE_DIR}/../llvm")
+    set(TOOLS_BINARY_DIR "${LLVM_TOOLS_BINARY_DIR}")
+    set(LIBRARY_DIR "${LLVM_LIBRARY_DIR}")
   endif()
 
-  set(LLVM_MAIN_INCLUDE_DIR ${MAIN_INCLUDE_DIR} CACHE PATH "Path to llvm/include")
-  set(LLVM_BINARY_DIR ${LLVM_OBJ_ROOT} CACHE PATH "Path to LLVM build tree")
-  set(LLVM_MAIN_SRC_DIR ${MAIN_SRC_DIR} CACHE PATH "Path to LLVM source tree")
-  set(LLVM_TOOLS_BINARY_DIR ${TOOLS_BINARY_DIR} CACHE PATH "Path to llvm/bin")
-  set(LLVM_LIBRARY_DIR ${LIBRARY_DIR} CACHE PATH "Path to llvm/lib")
+  set(LLVM_MAIN_INCLUDE_DIR "${MAIN_INCLUDE_DIR}" CACHE PATH "Path to llvm/include")
+  set(LLVM_BINARY_DIR "${LLVM_OBJ_ROOT}" CACHE PATH "Path to LLVM build tree")
+  set(LLVM_MAIN_SRC_DIR "${MAIN_SRC_DIR}" CACHE PATH "Path to LLVM source tree")
+  set(LLVM_TOOLS_BINARY_DIR "${TOOLS_BINARY_DIR}" CACHE PATH "Path to llvm/bin")
+  set(LLVM_LIBRARY_DIR "${LIBRARY_DIR}" CACHE PATH "Path to llvm/lib")
 
   find_program(LLVM_TABLEGEN_EXE "llvm-tblgen" ${LLVM_TOOLS_BINARY_DIR}
     NO_DEFAULT_PATH)
 
   # 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)

lld/CMakeLists.txt

 # Must go below project(..)
 include(GNUInstallDirs)
 
 if(LLD_BUILT_STANDALONE)
   set(CMAKE_INCLUDE_CURRENT_DIR ON)
 
   # Rely on llvm-config.
   set(LLVM_CONFIG_OUTPUT)
+  if(NOT LLVM_CONFIG)
+   # back compat
+   set(LLVM_CONFIG "${LLVM_CONFIG_PATH}")
+  endif()
   if(LLVM_CONFIG)
     set (LLVM_CONFIG_FOUND 1)
     message(STATUS "Found LLVM_CONFIG as ${LLVM_CONFIG}")
     message(DEPRECATION "Using llvm-config to detect the LLVM installation is \
           deprecated.  The installed cmake files should be used \
           instead.  CMake should be able to detect your LLVM install \
           automatically, but you can also use LLVM_DIR to specify \
           the path containing LLVMConfig.cmake.")
if(LLVM_CONFIG)
     list(GET LLVM_CONFIG_OUTPUT 3 LLVM_CONFIG_CMAKE_DIR)
 
     # Normalize LLVM_CMAKE_DIR. --cmakedir might contain backslashes.
     # CMake assumes slashes as PATH.
     file(TO_CMAKE_PATH ${LLVM_CONFIG_CMAKE_DIR} LLVM_CMAKE_DIR)
   endif()
 
   find_package(LLVM REQUIRED HINTS "${LLVM_CMAKE_DIR}")
-  list(APPEND CMAKE_MODULE_PATH ${LLVM_DIR})
+  list(APPEND CMAKE_MODULE_PATH "${LLVM_DIR}")
 
   # We can't check LLVM_CONFIG here, because find_package(LLVM ...) also sets
   # LLVM_CONFIG.
   if (NOT LLVM_CONFIG_FOUND)
     # Pull values from LLVMConfig.cmake.  We can drop this once the llvm-config
     # path is removed.
-    set(MAIN_INCLUDE_DIR ${LLVM_INCLUDE_DIR})
-    set(LLVM_OBJ_DIR ${LLVM_BINARY_DIR})
+    set(MAIN_INCLUDE_DIR "${LLVM_INCLUDE_DIR}")
+    set(LLVM_OBJ_DIR "${LLVM_BINARY_DIR}")
+    # N.B. this is just a default value, the CACHE PATHs below can be overriden.
+    set(MAIN_SRC_DIR "${CMAKE_CURRENT_SOURCE_DIR}/../llvm")
   endif()
 
-  set(LLVM_MAIN_INCLUDE_DIR ${MAIN_INCLUDE_DIR} CACHE PATH "Path to llvm/include")
-  set(LLVM_BINARY_DIR ${LLVM_OBJ_ROOT} CACHE PATH "Path to LLVM build tree")
-  set(LLVM_MAIN_SRC_DIR ${MAIN_SRC_DIR} CACHE PATH "Path to LLVM source tree")
+  set(LLVM_MAIN_INCLUDE_DIR "${MAIN_INCLUDE_DIR}" CACHE PATH "Path to llvm/include")
+  set(LLVM_BINARY_DIR "${LLVM_OBJ_ROOT}" CACHE PATH "Path to LLVM build tree")
+  set(LLVM_MAIN_SRC_DIR "${MAIN_SRC_DIR}" CACHE PATH "Path to LLVM source tree")
 
   find_program(LLVM_TABLEGEN_EXE "llvm-tblgen" ${LLVM_TOOLS_BINARY_DIR}
     NO_DEFAULT_PATH)
 
   # 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})