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libclc is mentioned in the list of LLVM_ENABLE_PROJECTS but it isn't actually possible to build it in-tree for various reasons. Users currently have to build it via LLVM_ENABLE_EXTERNAL_PROJECTS, which isn't very well documented. We can't properly build in-tree because the current system needs to "see" clang and other tools at CMake configuration time. The general idea is that we could fix this in the future by moving the compilation and linking of bitcode libraries to custom commands, which would remove the dependency on CMake configuration and would allow us to build libclc after clang and other tools are built in-tree. Since that's a bigger change, it is being left for later. Note that with this commit it's *still* not possible to properly build in-tree - this commit just fixes a few little things that are in the way. We are now able to build in-tree in the sense that it can be built as a regular LLVM sub-project, but the tools it uses to compile the libraries are still picked up from a pre-existing installation of LLVM, and not from tools built during the same build as libclc. The things fixed by this commit include: * Its use of CMAKE_SOURCE_DIR (i.e., assuming it was the top-level project) * These have been converted to PROJECT_SOURCE_DIR - should have no consequences for out-of-tree builds. * Its prepare_builtins tool insisting on linking against the dynamic LLVM.so. * This has been turned from an "llvm executable" into an "llvm utility" which links against the static libraries. * It was also missing a link component for the IRReader library. * Assuming an output path for its builtin libraries (dependent on the working directory) * This has been changed to query CMake for the library target's output file. * The spirv-mesa3d and spirv64-mesa3d targets were enabled by default (or when asking to build 'all' libclc targets), when they require llvm-spirv as an external dependency. * They are now only built when the user explicitly asks for them, or when llvm-spirv is available and the user asks for 'all'.
libclc ------ libclc is an open source, BSD licensed implementation of the library requirements of the OpenCL C programming language, as specified by the OpenCL 1.1 Specification. The following sections of the specification impose library requirements: * 6.1: Supported Data Types * 6.2.3: Explicit Conversions * 6.2.4.2: Reinterpreting Types Using as_type() and as_typen() * 6.9: Preprocessor Directives and Macros * 6.11: Built-in Functions * 9.3: Double Precision Floating-Point * 9.4: 64-bit Atomics * 9.5: Writing to 3D image memory objects * 9.6: Half Precision Floating-Point libclc is intended to be used with the Clang compiler's OpenCL frontend. libclc is designed to be portable and extensible. To this end, it provides generic implementations of most library requirements, allowing the target to override the generic implementation at the granularity of individual functions. libclc currently only supports the PTX target, but support for more targets is welcome. Compiling and installing with Make ---------------------------------- $ ./configure.py --with-llvm-config=/path/to/llvm-config && make $ make install Note you can use the DESTDIR Makefile variable to do staged installs. $ make install DESTDIR=/path/for/staged/install Compiling and installing with Ninja ----------------------------------- $ ./configure.py -g ninja --with-llvm-config=/path/to/llvm-config && ninja $ ninja install Note you can use the DESTDIR environment variable to do staged installs. $ DESTDIR=/path/for/staged/install ninja install Website ------- https://libclc.llvm.org/