LLVM support

.github/workflows/release.yml

@@ -72,19 +72,22 @@ jobs:
       uses: softprops/action-gh-release@v2
       with:
         files: |
-          assets/toolchain_linux*
+          assets/toolchain_gnu_linux*
+          assets/toolchain_llvm_linux*
 
     - name: Upload release assets (macOS toolchains)
       uses: softprops/action-gh-release@v2
       with:
         files: |
-          assets/toolchain_macos*
+          assets/toolchain_gnu_macos*
+          assets/toolchain_llvm_macos*
 
     - name: Upload release assets (Windows toolchains)
       uses: softprops/action-gh-release@v2
       with:
         files: |
-          assets/toolchain_windows*
+          assets/toolchain_gnu_windows*
+          assets/toolchain_llvm_windows*
 
     - name: Upload release assets (Distribution bundles)
       uses: softprops/action-gh-release@v2

.gitmodules

@@ -13,6 +13,9 @@
 [submodule "picolibc"]
 	path = picolibc
 	url = https://github.com/zephyrproject-rtos/picolibc.git
+[submodule "llvm"]
+	path = llvm
+	url = https://github.com/zephyrproject-rtos/llvm-project.git
 [submodule "crosskit-x86_64-apple-darwin"]
 	path = crosskit/crosskit-x86_64-apple-darwin
 	url = https://github.com/zephyrproject-rtos/crosskit-x86_64-apple-darwin.git

cmake/Zephyr-sdkConfig.cmake

@@ -11,7 +11,10 @@ set(SDK_MAJOR_MINOR_MICRO ${SDK_VERSION})
 
 get_filename_component(ZEPHYR_SDK_INSTALL_DIR ${CMAKE_CURRENT_LIST_DIR}/.. ABSOLUTE)
 set(ZEPHYR_SDK_INSTALL_DIR ${ZEPHYR_SDK_INSTALL_DIR})
-set(ZEPHYR_TOOLCHAIN_VARIANT zephyr)
+
+if(NOT DEFINED ZEPHYR_TOOLCHAIN_VARIANT)
+  set(ZEPHYR_TOOLCHAIN_VARIANT zephyr-gnu)
+endif()
 
 # Those are CMake package parameters.
 set(Zephyr-sdk_FOUND True)

cmake/zephyr/Kconfig

@@ -13,7 +13,8 @@ config TOOLCHAIN_ZEPHYR_SUPPORTS_GNU_EXTENSIONS
 
 config PICOLIBC_SUPPORTED
 	def_bool y
-	depends on "$(ZEPHYR_TOOLCHAIN_VARIANT)" = "zephyr"
+	depends on "$(ZEPHYR_TOOLCHAIN_VARIANT)" = "zephyr-gnu" \
+		|| "$(ZEPHYR_TOOLCHAIN_VARIANT)" = "zephyr-llvm"
 	help
 	  Zephyr SDK >=0.16 always supports Picolibc for C and C++ development.
 

cmake/zephyr/generic.cmake → cmake/zephyr/gnu/generic.cmake

@@ -1,6 +1,6 @@
 # SPDX-License-Identifier: Apache-2.0
 
-set(TOOLCHAIN_HOME ${ZEPHYR_SDK_INSTALL_DIR})
+set(TOOLCHAIN_HOME ${ZEPHYR_SDK_INSTALL_DIR}/gnu)
 
 set(COMPILER gcc)
 set(LINKER ld)
@@ -31,3 +31,4 @@ set(CROSS_COMPILE ${one_toolchain_root}/${CROSS_COMPILE_TARGET}/bin/${CROSS_COMP
 set(SYSROOT_DIR   ${one_toolchain_root}/${SYSROOT_TARGET}/${SYSROOT_TARGET})
 set(TOOLCHAIN_HAS_NEWLIB OFF CACHE BOOL "True if toolchain supports newlib")
 set(TOOLCHAIN_HAS_PICOLIBC ON CACHE BOOL "True if toolchain supports picolibc")
+set(TOOLCHAIN_HAS_GLIBCXX ON CACHE BOOL "True if toolchain supports libstdc++")

cmake/zephyr/target.cmake → cmake/zephyr/gnu/target.cmake

@@ -26,8 +26,8 @@ set(CROSS_COMPILE_TARGET_sparc     sparc-zephyr-elf)
 set(CROSS_COMPILE_TARGET ${CROSS_COMPILE_TARGET_${ARCH}})
 set(SYSROOT_TARGET       ${CROSS_COMPILE_TARGET})
 
-set(SYSROOT_DIR   ${ZEPHYR_SDK_INSTALL_DIR}/${SYSROOT_TARGET}/${SYSROOT_TARGET})
-set(CROSS_COMPILE ${ZEPHYR_SDK_INSTALL_DIR}/${CROSS_COMPILE_TARGET}/bin/${CROSS_COMPILE_TARGET}-)
+set(SYSROOT_DIR   ${ZEPHYR_SDK_INSTALL_DIR}/gnu/${SYSROOT_TARGET}/${SYSROOT_TARGET})
+set(CROSS_COMPILE ${ZEPHYR_SDK_INSTALL_DIR}/gnu/${CROSS_COMPILE_TARGET}/bin/${CROSS_COMPILE_TARGET}-)
 
 if("${ARCH}" STREQUAL "x86")
   if(CONFIG_X86_64)

cmake/zephyr/host-tools.cmake

@@ -1,7 +1,7 @@
 # SPDX-License-Identifier: Apache-2.0
 
 cmake_host_system_information(RESULT TOOLCHAIN_ARCH QUERY OS_PLATFORM)
-set(HOST_TOOLS_HOME ${ZEPHYR_SDK_INSTALL_DIR}/sysroots/${TOOLCHAIN_ARCH}-pokysdk-linux)
+set(HOST_TOOLS_HOME ${ZEPHYR_SDK_INSTALL_DIR}/hosttools/sysroots/${TOOLCHAIN_ARCH}-pokysdk-linux)
 
 # Path used for searching by the find_*() functions, with appropriate
 # suffixes added. Ensures that the SDK's host tools will be found when

cmake/zephyr/llvm/clang_compiler_rt.cfg

@@ -0,0 +1,4 @@
+# Copyright (c) 2023 The ChromiumOS Authors
+# SPDX-License-Identifier: Apache-2.0
+
+--rtlib=compiler-rt

cmake/zephyr/llvm/generic.cmake

@@ -0,0 +1,12 @@
+# SPDX-License-Identifier: Apache-2.0
+
+set(LLVM_TOOLCHAIN_PATH ${ZEPHYR_SDK_INSTALL_DIR}/llvm)
+
+set(TOOLCHAIN_HOME ${ZEPHYR_SDK_INSTALL_DIR}/llvm/bin)
+
+set(COMPILER clang)
+set(LINKER lld)
+set(BINTOOLS llvm)
+
+set(TOOLCHAIN_HAS_PICOLIBC ON CACHE BOOL "True if toolchain supports picolibc")
+set(TOOLCHAIN_HAS_LIBCXX ON CACHE BOOL "True if toolchain supports libc++")

cmake/zephyr/llvm/target.cmake

@@ -0,0 +1,43 @@
+# SPDX-License-Identifier: Apache-2.0
+
+if("${ARCH}" STREQUAL "arm")
+  if(DEFINED CONFIG_ARMV8_M_MAINLINE)
+    # ARMv8-M mainline is ARMv7-M with additional features from ARMv8-M.
+    set(triple armv8m.main-none-eabi)
+  elseif(DEFINED CONFIG_ARMV8_M_BASELINE)
+    # ARMv8-M baseline is ARMv6-M with additional features from ARMv8-M.
+    set(triple armv8m.base-none-eabi)
+  elseif(DEFINED CONFIG_ARMV7_M_ARMV8_M_MAINLINE)
+    # ARMV7_M_ARMV8_M_MAINLINE means that ARMv7-M or backward compatible ARMv8-M
+    # processor is used.
+    set(triple armv7m-none-eabi)
+  elseif(DEFINED CONFIG_ARMV6_M_ARMV8_M_BASELINE)
+    # ARMV6_M_ARMV8_M_BASELINE means that ARMv6-M or ARMv8-M supporting the
+    # Baseline implementation processor is used.
+    set(triple armv6m-none-eabi)
+  else()
+    # Default ARM target supported by all processors.
+    set(triple arm-none-eabi)
+  endif()
+elseif("${ARCH}" STREQUAL "arm64")
+  set(triple aarch64-none-elf)
+elseif("${ARCH}" STREQUAL "riscv")
+  if(CONFIG_64BIT)
+    set(triple riscv64-none-elf)
+  else()
+    set(triple riscv32-none-elf)
+  endif()
+endif()
+
+if(DEFINED triple)
+  set(CMAKE_C_COMPILER_TARGET   ${triple})
+  set(CMAKE_ASM_COMPILER_TARGET ${triple})
+  set(CMAKE_CXX_COMPILER_TARGET ${triple})
+
+  unset(triple)
+endif()
+
+list(APPEND TOOLCHAIN_C_FLAGS --config
+	${ZEPHYR_SDK_INSTALL_DIR}/cmake/zephyr/llvm/clang_compiler_rt.cfg)
+list(APPEND TOOLCHAIN_LD_FLAGS --config
+	${ZEPHYR_SDK_INSTALL_DIR}/cmake/zephyr/llvm/clang_compiler_rt.cfg)

release-notes.md

@@ -1,5 +1,23 @@
 # Notes / Changes in various releases
 
+## Zephyr SDK 0.18.0-alpha2
+
+- general:
+
+  * Added Clang/LLVM 19.1.1 toolchain with Arm and RISC-V architecture support.
+  * Introduced Clang/LLVM toolchain distribution bundle
+    (`zephyr-sdk-VER_HOST_llvm`).
+  * Renamed existing "full" GNU toolchain distribution bundle to
+    `zephyr-sdk-VER_HOST_gnu`.
+  * Windows executables now link against UCRT, which supports Unicode.
+
+- cmake:
+
+  * Restructured toolchain CMake script to support GNU and LLVM toolchains.
+    This requires Zephyr 4.1.0 or above (or the latest `collab-sdk-0.18-dev`).
+  * Zephyr SDK GNU toolchain now declares `TOOLCHAIN_HAS_GLIBCXX`.
+  * Zephyr SDK LLVM toolchain now declares `TOOLCHAIN_HAS_LIBCXX`.
+
 ## Zephyr SDK 0.17.1-rc1
 
 - general: