[Polly][CMake] Make PollyConfig.cmake relocatable like other projects'

This builds on D116521 to add this functionality to Polly without more copy-pasted code.

Reviewed By: beanz

Differential Revision: https://reviews.llvm.org/D116555

polly/CMakeLists.txt

@@ -48,10 +48,15 @@ endif ()
 set(POLLY_SOURCE_DIR ${CMAKE_CURRENT_SOURCE_DIR})
 set(POLLY_BINARY_DIR ${CMAKE_CURRENT_BINARY_DIR})
 
-# Add path for custom modules
-set(CMAKE_MODULE_PATH
-  ${CMAKE_MODULE_PATH}
-  "${CMAKE_CURRENT_SOURCE_DIR}/cmake"
+if(NOT DEFINED LLVM_COMMON_CMAKE_UTILS)
+  set(LLVM_COMMON_CMAKE_UTILS ${POLLY_SOURCE_DIR}/../cmake)
+endif()
+
+# Make sure that our source directory is on the current cmake module path so that
+# we can include cmake files from this directory.
+list(INSERT CMAKE_MODULE_PATH 0
+  "${POLLY_SOURCE_DIR}/cmake"
+  "${LLVM_COMMON_CMAKE_UTILS}/Modules"
   )
 
 include("polly_macros")
@@ -68,9 +73,6 @@ else ()
   set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -fno-exceptions -fno-rtti")
 endif ()
 
-# Add path for custom modules
-set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${POLLY_SOURCE_DIR}/cmake")
-
 SET(CMAKE_INSTALL_RPATH_USE_LINK_PATH TRUE)
 
 option(POLLY_ENABLE_GPGPU_CODEGEN "Enable GPGPU code generation feature" OFF)

polly/cmake/CMakeLists.txt

@@ -1,5 +1,7 @@
 # Keep this in sync with llvm/cmake/CMakeLists.txt!
 
+include(FindPrefixFromConfig)
+
 set(LLVM_INSTALL_PACKAGE_DIR "lib${LLVM_LIBDIR_SUFFIX}/cmake/llvm")
 set(POLLY_INSTALL_PACKAGE_DIR "lib${LLVM_LIBDIR_SUFFIX}/cmake/polly")
 if (CMAKE_CONFIGURATION_TYPES)
@@ -46,6 +48,7 @@ endif()")
 endif()
 
 # Generate PollyConfig.cmake for the build tree.
+set(POLLY_CONFIG_CODE "")
 set(POLLY_CONFIG_CMAKE_DIR "${CMAKE_BINARY_DIR}/${POLLY_INSTALL_PACKAGE_DIR}")
 set(POLLY_CONFIG_INCLUDE_DIRS
   ${POLLY_SOURCE_DIR}/include
@@ -79,24 +82,31 @@ file(GENERATE
 
 # Generate PollyConfig.cmake for the install tree.
 unset(POLLY_EXPORTS)
-set(POLLY_INSTALL_PREFIX "${CMAKE_INSTALL_PREFIX}")
-set(POLLY_CONFIG_LLVM_CMAKE_DIR "${LLVM_BINARY_DIR}/${LLVM_INSTALL_PACKAGE_DIR}")
-set(POLLY_CONFIG_CMAKE_DIR "${POLLY_INSTALL_PREFIX}/${POLLY_INSTALL_PACKAGE_DIR}")
-set(POLLY_CONFIG_LIBRARY_DIRS "${POLLY_INSTALL_PREFIX}/lib${LLVM_LIBDIR_SUFFIX}")
+find_prefix_from_config(POLLY_CONFIG_CODE POLLY_INSTALL_PREFIX "${POLLY_INSTALL_PACKAGE_DIR}")
+set(POLLY_CONFIG_LLVM_CMAKE_DIR "\${POLLY_INSTALL_PREFIX}/${LLVM_INSTALL_PACKAGE_DIR}")
+set(POLLY_CONFIG_CMAKE_DIR "\${POLLY_INSTALL_PREFIX}/${POLLY_INSTALL_PACKAGE_DIR}")
+set(POLLY_CONFIG_LIBRARY_DIRS "\${POLLY_INSTALL_PREFIX}/lib${LLVM_LIBDIR_SUFFIX}")
 if (POLLY_BUNDLED_ISL)
   set(POLLY_CONFIG_INCLUDE_DIRS
-    "${POLLY_INSTALL_PREFIX}/include"
-    "${POLLY_INSTALL_PREFIX}/include/polly"
+    "\${POLLY_INSTALL_PREFIX}/include"
+    "\${POLLY_INSTALL_PREFIX}/include/polly"
     )
 else()
   set(POLLY_CONFIG_INCLUDE_DIRS
-    "${POLLY_INSTALL_PREFIX}/include"
+    "\${POLLY_INSTALL_PREFIX}/include"
     ${ISL_INCLUDE_DIRS}
     )
 endif()
 
-# set locations for imported targets. The path is constructed to be relative to
-# the config file
+# Set locations for imported targets. The path is constructed to be relative to
+# the config file.
+#
+# Include the config code of PollyConfig.cmake to define POLLY_INSTALL_PREFIX
+# anew in case the export file is included alone rather than from that file.
+set(POLLY_EXPORTS
+"${POLLY_CONFIG_CODE}
+
+")
 foreach(tgt IN LISTS POLLY_CONFIG_EXPORTED_TARGETS)
   get_target_property(tgt_type ${tgt} TYPE)
   if (tgt_type STREQUAL "EXECUTABLE")
@@ -105,13 +115,12 @@ foreach(tgt IN LISTS POLLY_CONFIG_EXPORTED_TARGETS)
     set(tgt_prefix "lib/")
   endif()
 
-  set(tgt_path "${CMAKE_INSTALL_PREFIX}/${tgt_prefix}$<TARGET_FILE_NAME:${tgt}>")
-  file(RELATIVE_PATH tgt_path ${POLLY_CONFIG_CMAKE_DIR} ${tgt_path})
+  set(tgt_path "\${POLLY_INSTALL_PREFIX}/${tgt_prefix}$<TARGET_FILE_NAME:${tgt}>")
 
   if (NOT tgt_type STREQUAL "INTERFACE_LIBRARY")
     set(POLLY_EXPORTS
 "set_target_properties(${tgt} PROPERTIES
-        IMPORTED_LOCATION$<$<NOT:$<CONFIG:>>:_$<UPPER_CASE:$<CONFIG>>> \${CMAKE_CURRENT_LIST_DIR}/${tgt_path})
+        IMPORTED_LOCATION$<$<NOT:$<CONFIG:>>:_$<UPPER_CASE:$<CONFIG>>> \"${tgt_path}\")
 ${POLLY_EXPORTS}")
   endif()
 endforeach(tgt)

polly/cmake/PollyConfig.cmake.in

@@ -1,5 +1,7 @@
 # This file allows users to call find_package(Polly) and pick up our targets.
 
+@POLLY_CONFIG_CODE@
+
 find_package(LLVM REQUIRED CONFIG
              HINTS "@POLLY_CONFIG_LLVM_CMAKE_DIR@")