[Polly][Cmake] Optionally use a system isl version.

[philip.pfaffe]

Summary

This patch adds an option to build against a version of libisl already installed on the system. The installation is autodetected using the pkg-config file shipped with isl.

Usually the detection of the library would go into a FindISL.cmake module that creates an imported target. Here, I do this manually and in the root CMakeLists.txt. The main reason for this is that recent versions of FindPkgConfig (shipped with cmake 3.6 and up) will do this on their own. We should just wait until we can bump the minimum required cmake version to that point, or, if that's not going to happen soon, backport FindPkgConfig from cmake trunk (I didn't do this because I'm not up to speed on licensing).

BTW: The minimum required cmake version of Polly is currently 2.8 if built outside the LLVM tree. We should bump that at least to 3.4.3 to match LLVM.

[philip.pfaffe]

Fix small mistake.

[Meinersbur]

Thanks for the patch.

I did not understand the argument of not using a FindISL.cmake. You can have a FindISL.cmake and use FindPkgConfig in there? Once we bump to cmake 3.6 we can switch to using IMPORTED_TARGET in there and remove the manual creation of an imported target.

CMakeLists.txt

172

target_include_directories?

185

target_compile_options?

205–208

I'd prefer to declare a variable ISL_INCLUDE_DIRS that contains the required directories and is set by the POLLY_USE_EXTERNAL_ISL-handling mechanism to the directories of choice. It avoids having extra cases for POLLY_USE_EXTERNAL_ISL whenever it is used.

Would using target_include_directories(PollyISL INTERFACE ...) make this unnecessary?

lib/External/CMakeLists.txt

3

Indention

[philip.pfaffe]

Addressed the comments. I also took the liberty to advance the minimum required cmake version for building out-of-tree. This patch doesn't work with cmake 2.8, because IMPORTED targets aren't supported.

Nevertheless I stumbled onto a minor issue with this approach: if linked into the LLVM tools, the rpaths are lost. CMake builds everything with full rpath by default, but LLVM overwrites this with $ORIGIN/../lib. If Polly is linked statically into a tool, e.g. opt, the isl rpath is gone. Without putting libisl into the LD_LIBRARY_PATH, opt won't find it, or might even pick up the wrong one.

[philip.pfaffe]

CMakeLists.txt

185

This doesn't apply for IMPORTED targets.

[philip.pfaffe]

CMakeLists.txt

205–208

I'm using ISL_INCLUDE_DIRS now.

target_include_directories(PollyISL INTERFACE ...) doesn't easily work here, because you can't have source-tree or build-tree paths on a targets INTERFACE when it's being installed.

[Meinersbur]

Did you forget to add the additional files (cmake/CMakeLists.txt, cmake/FindIsl.cmake)?

I already commit the version bump to cmake 3.4.3.

[philip.pfaffe]

I absolutely did. The former was even superfluous.

[Meinersbur]

One suggestion left: I feel that the name POLLY_USE_EXTERNAL_ISL is ambiguous. Could be confused with LLVM_EXTERNAL_*. If it is OFF it uses isl from lib/External/isl. Could we change it to POLLY_BUNDLED_ISL and set it to ON by default? What do you think?

I tried it under Windows as well and it didn't work: no pkg-config available there. pkg_search_module also doesn't allow to configure the isl lib/include dirs manually. However, this is no concern atm as I don't know a reason why I would want an external isl on Windows.

[philip.pfaffe]

Renamed the POLLY_USE_EXTERNAL_ISL switch to POLLY_BUNDLED_ISL.

[Meinersbur]

Thanks.

I am going to commit it at the next occasion.

CMakeLists.txt

 endif(POLLY_ENABLE_GPGPU_CODEGEN)
 
 
 # Support GPGPU code generation if the library is available.
 if (CUDALIB_FOUND)
   INCLUDE_DIRECTORIES( ${CUDALIB_INCLUDE_DIR} )
 endif(CUDALIB_FOUND)
 
+option(POLLY_USE_EXTERNAL_ISL "Use a system libisl version" OFF)
+if (POLLY_USE_EXTERNAL_ISL)
+  find_package(PkgConfig REQUIRED)
+  pkg_search_module(SYSTEM_ISL isl)
+  if (NOT SYSTEM_ISL_FOUND EQUAL 1)
+    message(FATAL_ERROR "No libisl found on this system. Consider setting PKG_CONFIG_PATH.")
+  endif()
+  message(STATUS "Using external libisl in: ${SYSTEM_ISL_PREFIX}")
+
+  add_library(SystemISL INTERFACE IMPORTED)
+  foreach (incl IN LISTS SYSTEM_ISL_INCLUDE_DIRS)
+    set_property(TARGET SystemISL APPEND INTERFACE_INCLUDE_DIRECTORIES ${incl})
+  endforeach()
+  foreach (libname IN LISTS SYSTEM_ISL_LIBRARIES)
+    if (SYSTEM_ISL_LIBRARY_DIRS)
+      foreach (dir IN LISTS SYSTEM_ISL_LIBRARY_DIRS)
+        list(APPEND hints  ${dir})
+      endforeach()
+      list(APPEND hints NO_DEFAULT_PATH)
+    endif()
+    find_library(lib NAMES ${libname} ${hints})
+    set_property(TARGET SystemISL APPEND INTERFACE_LINK_LIBRARIES ${lib})
+  endforeach()
+  foreach (opt IN LISTS SYSTEM_ISL_CFLAGS SYSTEM_CFLAGS_OTHER)
+    set_property(TARGET SystemISL APPEND INTERFACE_COMPILE_OPTIONS ${opt})
+  endforeach()
+
+  set(ISL_TARGET SystemISL)
+else()
+  set(ISL_TARGET PollyISL)
+endif()
+
 include_directories(
   BEFORE
   ${CMAKE_CURRENT_SOURCE_DIR}/include
   ${CMAKE_CURRENT_SOURCE_DIR}/lib/JSON/include
-  ${CMAKE_CURRENT_BINARY_DIR}/lib/External/isl/include
-  ${CMAKE_CURRENT_SOURCE_DIR}/lib/External/isl/include
   ${CMAKE_CURRENT_SOURCE_DIR}/lib/External/pet/include
   ${CMAKE_CURRENT_SOURCE_DIR}/lib/External
   ${CMAKE_CURRENT_BINARY_DIR}/include
   )
 
+if (POLLY_USE_EXTERNAL_ISL)
+  include_directories(${SYSTEM_ISL_INCLUDE_DIRS})
+else()
+  include_directories(
+  ${CMAKE_CURRENT_BINARY_DIR}/lib/External/isl/include
+  ${CMAKE_CURRENT_SOURCE_DIR}/lib/External/isl/include
+  )
+endif()
+
 if (NOT LLVM_INSTALL_TOOLCHAIN_ONLY)
   install(DIRECTORY include/
     DESTINATION include
     FILES_MATCHING
     PATTERN "*.h"
     PATTERN ".svn" EXCLUDE
     )
 

lib/CMakeLists.txt

add_polly_library(Polly
   Transform/DeLICM.cpp
   ${POLLY_HEADER_FILES}
   )
 
 if (GPU_CODEGEN)
   target_link_libraries(Polly PollyPPCG)
 endif (GPU_CODEGEN)
 
-target_link_libraries(Polly PollyISL)
+target_link_libraries(Polly ${ISL_TARGET})
 
 if (BUILD_SHARED_LIBS)
   target_link_libraries(Polly
     LLVMSupport
     LLVMCore
     LLVMScalarOpts
     LLVMInstCombine
     LLVMTransformUtils

lib/External/CMakeLists.txt

 # External: Integer Set Library
+if (NOT POLLY_USE_EXTERNAL_ISL)
 set(ISL_SOURCE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/isl")
 set(ISL_BINARY_DIR "${CMAKE_CURRENT_BINARY_DIR}/isl")
 
 # Determine version of isl
 if (EXISTS "${ISL_SOURCE_DIR}/GIT_HEAD_ID")
   # The source comes from a 'make dist' archive
   file(READ "${ISL_SOURCE_DIR}/GIT_HEAD_ID" ISL_GIT_HEAD_ID)
   string(STRIP "${ISL_GIT_HEAD_ID}" ISL_GIT_HEAD_ID)
 elseif (EXISTS "${ISL_SOURCE_DIR}/gitversion.h")

 
 target_link_libraries(polly-isl-test
   PollyISL
 )
 
 # ISL requires at least C99 to compile. gcc < 5.0 use -std=gnu89 as default.
 target_enable_c99(PollyISL)
 target_enable_c99(polly-isl-test)
+endif (NOT POLLY_USE_EXTERNAL_ISL)
 
 set(PET_SOURCE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/pet")
 set(PPCG_SOURCE_DIR "${CMAKE_CURRENT_SOURCE_DIR}/ppcg")
 set(PPCG_BINARY_DIR "${CMAKE_CURRENT_BINARY_DIR}/ppcg")
 
 # Determine version of ppcg
 if (EXISTS "${PPCG_SOURCE_DIR}/GIT_HEAD_ID")
   # The source comes from a 'make dist' archive
include_directories(BEFORE
   ${PPCG_SOURCE_DIR}/include
   ${PET_SOURCE_DIR}/include
 )
 
 add_polly_library(PollyPPCG
   ${PPCG_FILES}
 )
 
-target_link_libraries(PollyPPCG PollyISL)
+target_link_libraries(PollyPPCG ${ISL_TARGET})
 
 # Disable warnings for upstream projects.
 if (MSVC)
   set(DISABLE_WARNING_FLAGS
     -wd4018 # 'expression' : signed/unsigned mismatch
     -wd4090 # 'operation' : different 'modifier' qualifiers
     -wd4200 # nonstandard extension used: zero-sized array in struct/union
     -wd4201 # nonstandard extension used: nameless struct/union
     -wd4334 # 'operator': result of 32-bit shift implicitly converted to 64 bits (was 64-bit shift intended?)
   )
+  if (NOT POLLY_USE_EXTERNAL_ISL)
     target_compile_options(PollyISL PRIVATE ${DISABLE_WARNING_FLAGS})
     target_compile_options(polly-isl-test PRIVATE ${DISABLE_WARNING_FLAGS})
+  endif (NOT POLLY_USE_EXTERNAL_ISL)
   target_compile_options(PollyPPCG PRIVATE ${DISABLE_WARNING_FLAGS})
 else ()
-  set_target_properties(PollyISL polly-isl-test PollyPPCG PROPERTIES
-    COMPILE_FLAGS "-w"
-  )
+  if (NOT POLLY_USE_EXTERNAL_ISL)
+    set_target_properties(PollyISL polly-isl-test PROPERTIES COMPILE_FLAGS "-w")
+  endif (NOT POLLY_USE_EXTERNAL_ISL)
+  set_target_properties(PollyPPCG PROPERTIES COMPILE_FLAGS "-w")
 endif ()
 
 if(MSVC)
   # In the Windows API (with some exceptions), the maximum length for a path is
   # MAX_PATH, which is defined as 260 characters. 
   target_compile_definitions(PollyPPCG PRIVATE "-DPATH_MAX=260")
 endif ()

test/CMakeLists.txt

 add_custom_target(check-polly)
 set_target_properties(check-polly PROPERTIES FOLDER "Polly")
 
 if (NOT DEFINED LLVM_MAIN_SRC_DIR)
 
   # We are building polly out of tree, adjust the settings.
   # FIXME: FileCheck is not available in llvm install directory at the moment.
   set(LLVM_LIT ${LLVM_INSTALL_ROOT}/bin/llvm-lit)
+  if (NOT POLLY_USE_EXTERNAL_ISL)
     set(POLLY_TEST_DEPS LLVMPolly polly-isl-test)
+  endif (NOT POLLY_USE_EXTERNAL_ISL)
   if (POLLY_GTEST_AVAIL)
     list(APPEND POLLY_TEST_DEPS PollyUnitTests)
   endif ()
 
   set(LLVM_BINARY_DIR "${LLVM_INSTALL_ROOT}")
   set(LLVM_TOOLS_DIR "${LLVM_INSTALL_ROOT}/bin")
   set(LLVM_LIBS_DIR "${LLVM_INSTALL_ROOT}/lib")
   set(POLLY_LIB_DIR "${POLLY_BINARY_DIR}/lib")
if (POLLY_GTEST_AVAIL)
                   DEPENDS PollyUnitTests
                   COMMENT "Running Polly unit tests")
       set_target_properties(check-polly-unittests PROPERTIES FOLDER "Polly")
     endif ()
     configure_file(
       ${CMAKE_CURRENT_SOURCE_DIR}/UnitIsl/lit.site.cfg.in
       ${CMAKE_CURRENT_BINARY_DIR}/UnitIsl/lit.site.cfg)
 
+
+    if (NOT POLLY_USE_EXTERNAL_ISL)
       add_custom_target(check-polly-isl
         command ${LLVM_LIT}
                   --param polly_site_config=${CMAKE_CURRENT_BINARY_DIR}/UnitIsl/lit.site.cfg
                   --param build_config=${CMAKE_CFG_INTDIR}
                   -sv ${POLLY_TEST_EXTRA_ARGS}
                   ${CMAKE_CURRENT_BINARY_DIR}
                   DEPENDS polly-isl-test
                   COMMENT "Running isl unit tests")
     set_target_properties(check-polly-isl PROPERTIES FOLDER "Polly")
+    endif (NOT POLLY_USE_EXTERNAL_ISL)
   endif()
 
 else (NOT DEFINED LLVM_MAIN_SRC_DIR)
 
   set(LLVM_LIT ${LLVM_TOOLS_BINARY_DIR}/llvm-lit)
-  set(POLLY_TEST_DEPS llvm-config opt LLVMPolly FileCheck not polly-isl-test)
+  set(POLLY_TEST_DEPS llvm-config opt LLVMPolly FileCheck not)
+  if (NOT POLLY_USE_EXTERNAL_ISL)
+    list(APPEND POLLY_TEST_DEPS polly-isl-test)
+  endif()
   if (POLLY_GTEST_AVAIL)
     list(APPEND POLLY_TEST_DEPS PollyUnitTests)
   endif ()
 
   set(LLVM_BINARY_DIR "${LLVM_BINARY_DIR}")
   set(LLVM_TOOLS_DIR "${LLVM_TOOLS_BINARY_DIR}")
   set(LLVM_LIBS_DIR "${LLVM_BINARY_DIR}/lib${LLVM_LIBDIR_SUFFIX}")
   set(POLLY_LIB_DIR "${LLVM_LIBS_DIR}")
add_lit_testsuite(check-polly-unittests "Running polly unit tests only"
       )
     set_target_properties(check-polly-unittests PROPERTIES FOLDER "Polly")
   endif ()
 
   configure_file(
     ${CMAKE_CURRENT_SOURCE_DIR}/UnitIsl/lit.site.cfg.in
     ${CMAKE_CURRENT_BINARY_DIR}/UnitIsl/lit.site.cfg)
 
+  if (NOT POLLY_USE_EXTERNAL_ISL)
     add_lit_testsuite(check-polly-isl "Running isl unit tests only"
       ${CMAKE_CURRENT_BINARY_DIR}/UnitIsl
       PARAMS polly_site_config=${CMAKE_CURRENT_BINARY_DIR}/UnitIsl/lit.site.cfg
       DEPENDS polly-isl-test
       )
     set_target_properties(check-polly-isl PROPERTIES FOLDER "Polly")
+  endif (NOT POLLY_USE_EXTERNAL_ISL)
 
   # Run polly-check-format as part of polly-check only if we are compiling with
   # clang, so clang-format is available.
   # if (TARGET clang-format) would be preferable, but this target is only added
   # after Polly, i.e. there is no such target yet at this point. The CMake cache
   # entry LLVM_TOOL_CLANG_BUILD will only be defined after clang has been
   # configured at least once, i.e. format will be checked only after a rerun of
   # CMake's configure.