set up julia_bindings structure

CMakeLists.txt

@@ -105,6 +105,19 @@ if (CMAKE_SOURCE_DIR STREQUAL CMAKE_CURRENT_SOURCE_DIR)
         message(STATUS "Building Python bindings disabled")
     endif ()
 
+    option(WITH_JULIA_BINDINGS "Build Julia bindings" ON)
+    if (WITH_JULIA_BINDINGS)
+        if (BUILD_SHARED_LIBS AND Halide_SHARED_LLVM)
+            message(STATUS "Building Julia bindings enabled")
+            add_subdirectory(julia_bindings)
+        else ()
+            message(WARNING "Building Julia bindings disabled: must compile with BUILD_SHARED_LIBS and Halide_SHARED_LLVM")
+            set(WITH_JULIA_BINDINGS OFF CACHE BOOL "Build Julia bindings" FORCE)
+        endif ()
+    else ()
+        message(STATUS "Building Julia bindings disabled")
+    endif ()
+
     option(WITH_TUTORIALS "Build tutorials" ON)
     if (WITH_TUTORIALS)
         message(STATUS "Building tutorials enabled")

julia_bindings/CMakeLists.txt

@@ -0,0 +1,26 @@
+##
+# Load Julia dependencies, including external JlCxx
+##
+cmake_minimum_required(VERSION 3.16)
+
+project(libhalide-julia)
+
+set(JLCXX_VER 0.8.2)
+find_package(jlcxx ${JLCXX_VER} QUIET)
+if (NOT jlcxx_FOUND)
+    include(FetchContent)
+    FetchContent_Declare(jlcxx
+                         GIT_REPOSITORY https://github.com/JuliaInterop/libcxxwrap-julia.git
+                         GIT_TAG v${JLCXX_VER})
+    FetchContent_MakeAvailable(jlcxx)
+endif ()
+
+# ##
+# # Add our sources to this sub-tree.
+# ##
+
+add_subdirectory(src)
+
+option(WITH_TEST_JULIA "Build Julia tests" ON)
+if (WITH_TESTS AND WITH_TEST_JULIA)
+endif ()

julia_bindings/Halide/Project.toml

@@ -0,0 +1,13 @@
+name = "Halide"
+uuid = "26cb47bb-16f4-45b8-86ca-ecaeb6ea8cd7"
+authors = ["Johnny Chen <johnnychen94@hotmail.com>"]
+version = "0.1.0"
+
+[deps]
+CxxWrap = "1f15a43c-97ca-5a2a-ae31-89f07a497df4"
+
+[extras]
+Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
+
+[targets]
+test = ["Test"]

julia_bindings/Halide/src/Halide.jl

@@ -0,0 +1,13 @@
+module Halide
+
+  using CxxWrap
+  # TODO: wrap this with jll package provided by BinaryBuilder to avoid hardcoded path
+  artifacts_root = joinpath(@__DIR__, "../../../build/julia_bindings/src")
+  @wrapmodule(joinpath(artifacts_root, "libhalide"), :define_func)
+
+
+  function __init__()
+    @initcxx
+  end
+
+end # module

julia_bindings/src/CMakeLists.txt

@@ -0,0 +1,23 @@
+set(SOURCES
+    JlHalide.cpp
+    JlFunc.cpp
+    )
+
+# CxxWrap requires this to be built as shared library
+add_library(Halide_Julia SHARED ${SOURCES})
+add_library(Halide::Julia ALIAS Halide_Julia)
+set_target_properties(Halide_Julia
+                      PROPERTIES
+                      LIBRARY_OUTPUT_NAME halide
+                      EXPORT_NAME Julia)
+
+target_include_directories(Halide_Julia PRIVATE ${jlcxx_SOURCE_DIR}/include)
+target_link_libraries(Halide_Julia PRIVATE Halide::Halide)
+target_link_libraries(Halide_Julia PUBLIC cxxwrap_julia)
+
+install(TARGETS
+    Halide_Julia
+    LIBRARY DESTINATION lib
+    ARCHIVE DESTINATION lib
+    RUNTIME DESTINATION lib
+)

julia_bindings/src/JlFunc.cpp

@@ -0,0 +1,18 @@
+#include "JlFunc.h"
+
+#include <string>
+#include <vector>
+
+namespace Halide {
+namespace JuliaBindings {
+
+
+JLCXX_MODULE define_func(jlcxx::Module& m) {
+    m.add_type<Func>("Func")
+        .constructor<const std::string&>()
+        .constructor<>()
+        .method("name", &Func::name);
+}
+
+}  // namespace JuliaBindings
+}  // namespace Halide

julia_bindings/src/JlFunc.h

@@ -0,0 +1,14 @@
+#ifndef HALIDE_JULIA_BINDINGS_JLFUNC_H
+#define HALIDE_JULIA_BINDINGS_JLFUNC_H
+
+#include "JlHalide.h"
+
+namespace Halide {
+namespace JuliaBindings {
+
+JLCXX_MODULE define_func(jlcxx::Module& m);
+
+}  // namespace JuliaBindings
+}  // namespace Halide
+
+#endif  // HALIDE_JULIA_BINDINGS_JLFUNC_H

julia_bindings/src/JlHalide.cpp

@@ -0,0 +1,11 @@
+#include "JlHalide.h"
+
+static_assert(JLCXX_VERSION_MAJOR == 0 && JLCXX_VERSION_MINOR == 8 && JLCXX_VERSION_PATCH >= 2,
+              "Halide requires JlCxx 0.8.2+");
+
+namespace Halide {
+namespace JuliaBindings {
+
+
+}  // namespace JuliaBindings
+}  // namespace Halide

julia_bindings/src/JlHalide.h

@@ -0,0 +1,10 @@
+#ifndef HALIDE_JULIA_BINDINGS_JLHALIDE_H
+#define HALIDE_JULIA_BINDINGS_JLHALIDE_H
+
+#include <jlcxx/jlcxx_config.hpp> // For compatibility check
+#include <jlcxx/jlcxx.hpp>
+
+// Everyone needs Halide.h
+#include "Halide.h"
+
+#endif  // HALIDE_JULIA_BINDINGS_JLHALIDE_H