Add hello world example

hello_world/CMakeLists.txt

@@ -0,0 +1,53 @@
+# SPDX-License-Identifier: Apache-2.0
+
+cmake_minimum_required(VERSION 3.20.0)
+find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})
+project(ldc_hello_world)
+
+target_sources(app PRIVATE src/main.c)
+
+if(${ARCH} STREQUAL "posix" OR ${ARCH} STREQUAL "x86")
+    set(ldc_target i686-unknown-none-newlibeabi)
+elseif(CONFIG_CPU_CORTEX_M)
+    if(CONFIG_CPU_CORTEX_M3)
+        set(ldc_target thumbv7em-unknown-none-newlibeabi)
+    else()
+        message(FATAL_ERROR "Unknown Cortex-M target")
+    endif()
+elseif(CONFIG_RISCV)
+    if(CONFIG_RISCV_ISA_RV32I)
+        set(ldc_target riscv32-unknown-newlib-elf)
+    else()
+        message(FATAL_ERROR "Unsupported riscv ISA")
+    endif()
+else()
+    message(FATAL_ERROR "ARCH ${ARCH} not supported")
+endif()
+
+include(ExternalProject)
+set(ldc_src_dir ${CMAKE_CURRENT_SOURCE_DIR})
+ExternalProject_Add(
+    ldc_project
+    PREFIX  ${CMAKE_CURRENT_BINARY_DIR}
+    SOURCE_DIR  ${ldc_src_dir}
+    BUILD_IN_SOURCE 1
+    BUILD_ALWAYS    1
+    CONFIGURE_COMMAND   ""
+    BUILD_COMMAND
+        dub
+        build
+        -f
+        -b release
+        --compiler=ldc2
+        --arch=${ldc_target}
+    INSTALL_COMMAND ""
+    BUILD_BYPRODUCTS    ${ldc_src_dir}/lib/libhelloworld.a
+)
+
+add_library(ldc_lib STATIC IMPORTED GLOBAL)
+add_dependencies(
+    ldc_lib
+    ldc_project
+)
+set_target_properties(ldc_lib PROPERTIES IMPORTED_LOCATION ${ldc_src_dir}/lib/libhelloworld.a)
+target_link_libraries(app PUBLIC ldc_lib)

hello_world/dub.sdl

@@ -0,0 +1,7 @@
+name "hello_world"
+authors "Hiroki Noda"
+license "BSL-1.0"
+targetType "staticLibrary"
+targetPath "lib"
+targetName "helloworld"
+dependency "zephyr-core" path="../zephyr-core"

hello_world/ldc2.conf

@@ -0,0 +1,14 @@
+default:
+{
+    switches = [
+        "-Os",
+        "--betterC",
+        "--float-abi=soft",
+        "--relocation-model=static",
+        "--defaultlib="
+    ];
+    post-switches = [
+        "-I%%ldcbinarypath%%/../import",
+    ];
+    lib-dirs = [];
+}

hello_world/prj.conf

@@ -0,0 +1,4 @@
+CONFIG_NEWLIB_LIBC=y
+CONFIG_POSIX_API=y
+CONFIG_MAIN_STACK_SIZE=2048
+CONFIG_LINKER_ORPHAN_SECTION_PLACE=y

hello_world/sample.yaml

@@ -0,0 +1,9 @@
+sample:
+  description: hello world
+  name: helloworld
+common:
+  build_only: true
+  platform_allow:
+    - qemu_cortex_m3
+tests:
+  app.default: {}

hello_world/src/app.d

@@ -0,0 +1,10 @@
+import zephyr.core.stdc.stdio;
+
+extern(C):
+nothrow:
+@nogc:
+
+void d_main()
+{
+    printf("Hello, World!\n");
+}

hello_world/src/main.c

@@ -0,0 +1,6 @@
+extern void d_main(void);
+
+int main(void) {
+    d_main();
+    return 0;
+}