When is `LLVM_PATH` needed?

[bberberov]

Hello,

I have built freestanding cling RPM packages from version 1.2, as mentioned in #559.

I had some issues with the build and I narrowed it down to this section of cmake code:

cling/lib/Interpreter/CMakeLists.txt

Lines 401 to 405 in 2fdcb6d

	# If both LLVM and Clang are external, we need to define LLVM_PATH in order for
	# cling to use the correct (external) LLVM/Clang directories.
	if ((NOT builtin_llvm) AND (NOT builtin_clang))
	target_compile_definitions(clingInterpreter PUBLIC "LLVM_PATH=\"${LLVM_BINARY_DIR}\"")
	endif()

I don't understand in which cases this would apply, and what options I need to pass to cmake to avoid it. Right now I just patch lib/Interpreter/CMakeLists.txt at build-time to remove it, and cling stops producing error messages at runtime. Could you explain when this is needed? Maybe there is something wrong with my build that I haven't yet seen at runtime.

[pcanal]

Can you put here the error message you seeing and what action leads to them?

[bberberov]

I'm pretty sure it's this one, but I'll make a build to verify, and post the terminal output.

cling/lib/Interpreter/CIFactory.cpp

Lines 380 to 382 in 2fdcb6d

	cling::errs()
	<< "ERROR in cling::CIFactory::createCI():\n resource directory "
	<< resourcePath << " not found!\n";

I just start the cling REPL which in my case is /opt/cling/bin/cling, with no arguments.

[pcanal]

I'm pretty sure it's this one, but I'll make a build to verify, and post the terminal output.

Thanks when doing so, also include the build location and install location (if any).

[bberberov]

▶ /opt/cling/bin/cling
ERROR in cling::CIFactory::createCI():
  resource directory /home/abuild/rpmbuild/BUILD/cling-1.2-build/cling-1.2/build/lib/clang/18 not found!

****************** CLING ******************
* Type C++ code and press enter to run it *
*             Type .q to exit             *
*******************************************
[cling]$ .q

It's built on OBS from a SPEC file. I set it up to install in /opt/cling so it can coexist with the system clang. You can see the CMake invocation in each SPEC file from the links below:

The develop version does not have the CMake patch, so it shows the issue, the testing version does.

• develop
• testing

I've build for several distros, but only tested the openSUSE Tumbleweed one so far.

[bberberov]

I'll start trying to build 1.3 later today.

[bberberov]

An initial build has succeeded, but I'm having new issues. Will need more testing.

So far I've needed this additional patch:

diff --git i/lib/CMakeLists.txt w/lib/CMakeLists.txt
index eb29252..63d4f1e 100644
--- i/lib/CMakeLists.txt
+++ w/lib/CMakeLists.txt
@@ -8,7 +8,5 @@
 
 add_subdirectory(Interpreter)
 add_subdirectory(MetaProcessor)
-if(CLING_INCLUDE_TESTS)
-   add_subdirectory(UserInterface)
-endif()
+add_subdirectory(UserInterface)
 add_subdirectory(Utils)

I set CLING_INCLUDE_TESTS=OFF and BUILD_SHARED_LIBS=OFF, and the build fails with ld: cannot find -lclingUserInterface: No such file or directory without the patch above.

The original question remains. I don't understand when this segment applies (now in v1.3).

cling/lib/Interpreter/CMakeLists.txt

Lines 401 to 405 in af630d9

	# If both LLVM and Clang are external, we need to define LLVM_PATH in order for
	# cling to use the correct (external) LLVM/Clang directories.
	if ((NOT builtin_llvm) AND (NOT builtin_clang))
	target_compile_definitions(clingInterpreter PUBLIC "LLVM_PATH=\"${LLVM_BINARY_DIR}\"")
	endif()

I did a search and builtin_llvm and builtin_clang only occur in this file.

[ferdymercury]

I did a search and builtin_llvm and builtin_clang only occur in this file.

Those are flags used when building Cling as part of ROOT

I set CLING_INCLUDE_TESTS=OFF and BUILD_SHARED_LIBS=OFF, and the build fails with ld: cannot find -lclingUserInterface: No such file or directory without the patch above.

Maybe @guitargeek has ideas