Merge branch main into dev/instantiate_linking

- fix: when load aot init expr,no type_idx set. (bytecodealliance#4094)
- Cmake improvements (bytecodealliance#4076)
- fix(aot_emit_aot_file): prevent buffer emission for zero byte_count (bytecodealliance#4095)
- fix(unit-test): libc_builtin_test issues (bytecodealliance#4073)
- feat: add support for EXTERNREF value type and enable AOT validator in fuzz tests (bytecodealliance#4083)
- [gc] Subtyping fix (bytecodealliance#4075)
- Add a conditional check for the macro __STDC_VERSION__ (bytecodealliance#4080)
- Unit test:type matching issue and code redundancy (bytecodealliance#4079)
- build(deps): Bump github/codeql-action from 3.28.8 to 3.28.9 (bytecodealliance#4074)
- fix(aot): ensure value_cmp does not exceed br_count in branch table compilation (bytecodealliance#4065)
- In wasm32, fix potential conversion overflow when enlarging 65536 pages (bytecodealliance#4064)
- [fuzzing] execute every exported function (bytecodealliance#3959)
- Update memory allocation functions to use allocator user data (bytecodealliance#4043)
- Show wasm proposals status during compilation and execution (bytecodealliance#3989)
- add a validator for aot module (bytecodealliance#3995)
- Use wasm32-wasip1 instead of wasm32-wasi target for rust code (bytecodealliance#4057)
- Update Rust target from 'wasm32-wasi' to 'wasm32-wasip1' in CI (bytecodealliance#4050)
- Fix wasm loader check data segment count (bytecodealliance#4039)
- Synchronize the GC spec tests to the commit from December 9. 2024. (bytecodealliance#4022)
- Refine getting const offsets in wasm loader of fast-interp (bytecodealliance#4012)
- fixes for compiling on windows (bytecodealliance#4026)
- .github: Add shared lib builds (bytecodealliance#3975)
- Refine read leb int wasm loader of fast interpreter (bytecodealliance#4017)
- build(deps): Bump github/codeql-action from 3.28.0 to 3.28.1 (bytecodealliance#4020)
- build(deps): Bump actions/upload-artifact from 4.5.0 to 4.6.0 (bytecodealliance#4021)
- Enable shrunk memory by default and add related configurations (bytecodealliance#4008)
- Add documentation regarding security issues and the status of Wasm proposals (bytecodealliance#3972)
- Improve stack consistency by ensuring sufficient space for dummy offsets (bytecodealliance#4011)
- Check whether related table has funcref elem in opcode call_indirect (bytecodealliance#3999)
- [fuzzing] Use software bound-check during fuzzing (bytecodealliance#4003)
- Add an example of how to embed WAMR in Zephyr user mode  (bytecodealliance#3998)
- Fix table index calculations in wasm_loader and wasm_mini_loader (bytecodealliance#4004)
- Ensure __heap_base and __data_end global indices are validated against import count (bytecodealliance#3996)
- Error message improvement (bytecodealliance#4000)
- Handle a new scenario where an item is both exported and imported. (bytecodealliance#3984)
- Optimize memory initialization handling in AOT loader (bytecodealliance#3983)
- build(deps): Bump actions/upload-artifact from 4.4.3 to 4.5.0 (bytecodealliance#3981)
- build(deps): Bump github/codeql-action from 3.27.9 to 3.28.0 (bytecodealliance#3982)
- Add Tianlong into code owners (bytecodealliance#3970)
- Set thread information earlier in exec_env creation (bytecodealliance#3967)
- top-level cmake: link llvm libraries to our shared library (bytecodealliance#3973)
- add reference type support by default for darwin to support WASI-SDK-25 (bytecodealliance#3978)
- CMakeLists.txt: Do not require C++ (bytecodealliance#3956)
- [fuzzing] Enable instantiation (bytecodealliance#3958)
- use a random secret key (bytecodealliance#3971)
- top-level cmakefile: fix macOS build (bytecodealliance#3968)
- Only access Zephyr thread stats info when it's available (bytecodealliance#3962)
- build(deps): Bump github/codeql-action from 3.27.6 to 3.27.9 (bytecodealliance#3960)
- wasm_export.h: Use "default" visibility for gcc and clang (bytecodealliance#3957)
- set alignment 4 when loading multi return value (bytecodealliance#3955)
- Fix aot table instantiate (bytecodealliance#3946)
- Consume the placeholders that were put when emitting table info (bytecodealliance#3940)
- Refactor SConscript and add file checks in iwasm.c (bytecodealliance#3945)
- Improvements for platform thread APIs on Windows and Zephyr (bytecodealliance#3941)
- Fix incorrect assignment in win_file.c (bytecodealliance#3939)
- don't return an uninitialized trap if argv_to_results fails (bytecodealliance#3935)
- support WASM_FUNCREF return type in argv_to_results (bytecodealliance#3936)
- add thread cpu time for zephyr (bytecodealliance#3937)
- build(deps): bump github/codeql-action from 3.27.4 to 3.27.5 (bytecodealliance#3931)
- Update README.md to clarify Windows toolchain support and ESP-IDF reference (bytecodealliance#3917)
- Enable ref types by default (bytecodealliance#3894)
- Fix loader small bug (bytecodealliance#3928)
- add testcases for shared heap and fix POP_MEM_OFFSET of memory64 (bytecodealliance#3916)
- Use plain assignment rather than bh_memcpy_s (bytecodealliance#3924)
- Fix WASI Path Mapping Processing (bytecodealliance#3923)
- Drop declarative elements on module instantiation (bytecodealliance#3922)
- Check possible integer overflow in aot memory boundary check (bytecodealliance#3920)
- Fix CI wamr-ide error (bytecodealliance#3913)
- Support external toolchain on Windows for aot compiler (bytecodealliance#3911)
- build(deps): bump github/codeql-action from 3.27.1 to 3.27.4 (bytecodealliance#3912)
- Correct the table index calculation in aot_instantiation (bytecodealliance#3903)
- Fix a leak in wasm_loader_emit_br_info (bytecodealliance#3900)
- GlobalValueSet was moved to IRPartitionLayer recently, but we have a local definition anyway (bytecodealliance#3899)
- build(deps): bump github/codeql-action from 3.27.0 to 3.27.1 (bytecodealliance#3902)
- Fix linked global initialization in multimodule (bytecodealliance#3905)
- Wasm loader enhancement: check code size in code entry  (bytecodealliance#3892)
- Refactor AOT loader to support compatible versions (bytecodealliance#3891)
- Fix out of bounds issue in is_native_addr_in_shared_heap function (bytecodealliance#3886)
- Fix mmap flags for AOT loader on non-Linux SGX platforms (bytecodealliance#3890)
- Bump AOT_CURRENT_VERSION for WAMR 2.x (gc, memory64) (bytecodealliance#3880)
- Refine looking up aot function with index (bytecodealliance#3882)
- build(deps): bump github/codeql-action from 3.26.13 to 3.27.0 (bytecodealliance#3888)
- fix(ios): Remove `float-abi` flag (bytecodealliance#3889)
- Fix out of bounds issues after memory.grow on non-aot non-threads builds (bytecodealliance#3872)
- Exclude fuzz test python and npm packages in scoreboard scan (bytecodealliance#3871)

Author: Chris Woods <[email protected]>
Author: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Author: Dylan Johnston <[email protected]>
Author: edoardo <[email protected]>
Author: eric <[email protected]>
Author: Fadumina Barre <[email protected]>
Author: Huang Qi <[email protected]>
Author: James Ring <[email protected]>
Author: Jérôme Vouillon <[email protected]>
Author: kk <[email protected]>
Author: [email protected] <[email protected]>
Author: liang.he <[email protected]>
Author: Maks Litskevich <[email protected]>
Author: Marcin Kolny <[email protected]>
Author: peter-tatrai <[email protected]>
Author: TianlongLiang <[email protected]>
Author: Tomáš Malý <[email protected]>
Author: Viacheslav Palchikov <[email protected]>
Author: WenLY1 <[email protected]>
Author: Wenyong Huang <[email protected]>
Author: Xavier Del Campo <[email protected]>
Author: YAMAMOTO Takashi <[email protected]>
Author: yangkun27 <[email protected]>

.github/workflows/build_llvm_libraries.yml

@@ -65,6 +65,7 @@ jobs:
         shell: bash
         run: |
           echo "last_commit=$(GH_TOKEN=${{ secrets.GITHUB_TOKEN }} /usr/bin/env python3 ./build_llvm.py ${{ inputs.extra_build_llvm_options }} --llvm-ver)" >> $GITHUB_OUTPUT
+        working-directory: build-scripts
 
       # Bump the prefix number to evict all previous caches and
       # enforce a clean build, in the unlikely case that some

.github/workflows/check_version_h.yml

@@ -0,0 +1,29 @@
+# Copyright (C) 2019 Intel Corporation.  All rights reserved.
+# SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+name: confirm version.h stay in sync
+
+on:
+  workflow_call:
+
+permissions:
+  contents: read
+
+jobs:
+  confirm_version:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: checkout
+        uses: actions/checkout@v4
+
+      - name: cmake execute to generate version.h
+        run: cmake -B build_version -S .
+
+      - name: confirm version.h
+        run: |
+          if [ -z "$(git status --porcelain | grep version.h)" ]; then
+            echo "version.h is in sync"
+          else
+            echo "version.h is not in sync"
+            exit 1
+          fi

.github/workflows/codeql.yml

@@ -53,7 +53,7 @@ jobs:
 
     # Initializes the CodeQL tools for scanning.
     - name: Initialize CodeQL
-      uses: github/codeql-action/init@v3.27.4
+      uses: github/codeql-action/init@v3.28.9
       with:
         languages: ${{ matrix.language }}
 
@@ -70,7 +70,7 @@ jobs:
     - run: |
         ./.github/scripts/codeql_buildscript.sh
     - name: Perform CodeQL Analysis
-      uses: github/codeql-action/analyze@v3.27.4
+      uses: github/codeql-action/analyze@v3.28.9
       with:
         category: "/language:${{matrix.language}}"
         upload: false
@@ -99,14 +99,14 @@ jobs:
         output: ${{ steps.step1.outputs.sarif-output }}/cpp.sarif
 
     - name: Upload CodeQL results to code scanning
-      uses: github/codeql-action/upload-sarif@v3.27.4
+      uses: github/codeql-action/upload-sarif@v3.28.9
       with:
         sarif_file: ${{ steps.step1.outputs.sarif-output }}
         category: "/language:${{matrix.language}}"
 
     - name: Upload CodeQL results as an artifact
       if: success() || failure()
-      uses: actions/upload-artifact@v4.4.3
+      uses: actions/upload-artifact@v4.6.0
       with:
         name: codeql-results
         path: ${{ steps.step1.outputs.sarif-output }}

.github/workflows/compilation_on_android_ubuntu.yml

@@ -74,6 +74,12 @@ permissions:
   contents: read
 
 jobs:
+  check_version_h:
+    permissions:
+      contents: read
+      actions: write
+    uses: ./.github/workflows/check_version_h.yml
+
   build_llvm_libraries_on_ubuntu_2204:
     permissions:
       contents: read
@@ -156,6 +162,7 @@ jobs:
             "-DWAMR_DISABLE_HW_BOUND_CHECK=1",
             "-DWAMR_BUILD_MEMORY64=1",
             "-DWAMR_BUILD_MULTI_MEMORY=1",
+            "-DWAMR_BUILD_SHARED=1",
           ]
         os: [ubuntu-22.04]
         platform: [android, linux]
@@ -253,6 +260,9 @@ jobs:
             platform: android
           - make_options_run_mode: $LLVM_EAGER_JIT_BUILD_OPTIONS
             platform: android
+          # android does not support WAMR_BUILD_SHARED in its CMakeLists.txt.
+          - make_options_feature: "-DWAMR_BUILD_SHARED=1"
+            platform: android
         include:
           - os: ubuntu-22.04
             llvm_cache_key: ${{ needs.build_llvm_libraries_on_ubuntu_2204.outputs.cache_key }}
@@ -671,7 +681,7 @@ jobs:
             test_option: $MEMORY64_TEST_OPTIONS
           - running_mode: "multi-tier-jit"
             test_option: $MEMORY64_TEST_OPTIONS
-          # aot, fast-interp, fast-jit, llvm-jit, multi-tier-jit don't support Multi Memory 
+          # aot, fast-interp, fast-jit, llvm-jit, multi-tier-jit don't support Multi Memory
           - running_mode: "aot"
             test_option: $MULTI_MEMORY_TEST_OPTIONS
           - running_mode: "fast-interp"
@@ -813,7 +823,7 @@ jobs:
 
       - name: install dependencies
         run: |
-          rustup target add wasm32-wasi
+          rustup target add wasm32-wasip1
           sudo apt update && sudo apt-get install -y lld ninja-build
           npm install
         working-directory: test-tools/wamr-ide/VSCode-Extension

.github/workflows/nightly_run.yml

@@ -142,6 +142,7 @@ jobs:
             "-DWAMR_DISABLE_HW_BOUND_CHECK=1",
             "-DWAMR_BUILD_MEMORY64=1",
             "-DWAMR_BUILD_MULTI_MEMORY=1",
+            "-DWAMR_BUILD_SHARED=1",
           ]
         os: [ubuntu-20.04]
         platform: [android, linux]

.github/workflows/spec_test_on_nuttx.yml

@@ -127,7 +127,8 @@ jobs:
         wamr_feature_option:
           # Empty option for default
           - { option: "", mode: "" }
-          - { option: "CONFIG_INTERPRETERS_WAMR_GC CONFIG_INTERPRETERS_WAMR_AOT_STACK_FRAME", mode: "-G" }
+          # need to install menhir
+          # - { option: "CONFIG_INTERPRETERS_WAMR_GC CONFIG_INTERPRETERS_WAMR_AOT_STACK_FRAME", mode: "-G" }
 
         exclude:
           # XIP is not fully supported yet on RISCV64, some relocations can not be resolved
@@ -208,7 +209,7 @@ jobs:
         if: contains(matrix.wamr_test_option.mode, 'aot')
         working-directory: apps/interpreters/wamr/wamr/wamr-compiler
         run: |
-          cmake -Bbuild .
+          cmake -B build -DWAMR_BUILD_SHRUNK_MEMORY=0 -S .
           cmake --build build
 
       # the nuttx version we use for xtensa requires esptool.py newer than
@@ -350,7 +351,7 @@ jobs:
 
       - name: upload the log
         if: always()
-        uses: actions/upload-artifact@v4.4.3
+        uses: actions/upload-artifact@v4.6.0
         with:
           name: spec-test-log-${{ github.run_id }}-${{ strategy.job-index }}-${{ matrix.target_config.target }}
           path: log

.github/workflows/supply_chain.yml

@@ -52,14 +52,14 @@ jobs:
       # Upload the results as artifacts (optional). Commenting out will disable uploads of run results in SARIF
       # format to the repository Actions tab.
       - name: "Upload artifact"
-        uses: actions/upload-artifact@184d73b71b93c222403b2e7f1ffebe4508014249 # v3.1.0
+        uses: actions/upload-artifact@65c4c4a1ddee5b72f698fdd19549f0f0fb45cf08 # v3.1.0
         with:
           name: SARIF file
           path: results.sarif
           retention-days: 5
 
       # Upload the results to GitHub's code scanning dashboard.
       - name: "Upload to code-scanning"
-        uses: github/codeql-action/upload-sarif@a1695c562bbfa68dc5ab58c9b5e9f616b52bf5be # v2.2.4
+        uses: github/codeql-action/upload-sarif@0a35e8f6866a39b001e5f7ad1d0daf9836786896 # v2.2.4
         with:
           sarif_file: results.sarif

CMakeLists.txt

@@ -3,26 +3,23 @@
 
 cmake_minimum_required (VERSION 3.0)
 
+option(BUILD_SHARED_LIBS "Build using shared libraries" OFF)
+
 if(ESP_PLATFORM)
   include (${COMPONENT_DIR}/build-scripts/esp-idf/wamr/CMakeLists.txt)
   return()
 endif()
 
-project (iwasm)
+project (iwasm LANGUAGES C)
+
+set(CMAKE_CXX_STANDARD 17)
 
 set (CMAKE_VERBOSE_MAKEFILE OFF)
 
 if (NOT DEFINED WAMR_BUILD_PLATFORM)
   string (TOLOWER ${CMAKE_HOST_SYSTEM_NAME} WAMR_BUILD_PLATFORM)
 endif ()
 
-if (NOT DEFINED WAMR_BUILD_STATIC)
-  set (WAMR_BUILD_STATIC 1)
-endif ()
-if (NOT DEFINED WAMR_BUILD_SHARED)
-  set (WAMR_BUILD_SHARED 1)
-endif ()
-
 # Reset default linker flags
 set (CMAKE_SHARED_LIBRARY_LINK_C_FLAGS "")
 set (CMAKE_SHARED_LIBRARY_LINK_CXX_FLAGS "")
@@ -113,8 +110,8 @@ if (NOT DEFINED WAMR_BUILD_SIMD)
 endif ()
 
 if (NOT DEFINED WAMR_BUILD_REF_TYPES)
-  # Disable reference types by default
-  set (WAMR_BUILD_REF_TYPES 0)
+  # Enable reference types by default
+  set (WAMR_BUILD_REF_TYPES 1)
 endif ()
 
 set (WAMR_ROOT_DIR ${CMAKE_CURRENT_SOURCE_DIR})
@@ -154,52 +151,40 @@ if (MSVC)
   add_definitions(-DCOMPILING_WASM_RUNTIME_API=1)
 endif ()
 
-# STATIC LIBRARY
-if (WAMR_BUILD_STATIC)
-    add_library(iwasm_static STATIC ${WAMR_RUNTIME_LIB_SOURCE})
-    set_target_properties (iwasm_static PROPERTIES OUTPUT_NAME vmlib)
-    target_include_directories(iwasm_static INTERFACE ${WAMR_ROOT_DIR}/core/iwasm/include)
-    target_link_libraries (iwasm_static INTERFACE ${LLVM_AVAILABLE_LIBS} ${UV_A_LIBS} -lm -ldl ${CMAKE_THREAD_LIBS_INIT})
-    if (WAMR_BUILD_WASM_CACHE EQUAL 1)
-      target_link_libraries(iwasm_static INTERFACE boringssl_crypto)
-    endif ()
+add_library (vmlib ${WAMR_RUNTIME_LIB_SOURCE})
+set_target_properties (vmlib PROPERTIES OUTPUT_NAME iwasm)
+target_include_directories(vmlib INTERFACE
+  $<BUILD_INTERFACE:${WAMR_ROOT_DIR}/core/iwasm/include>
+  $<INSTALL_INTERFACE:include/iwasm>
+)
 
-    if (MINGW)
-      target_link_libraries (iwasm_static PRIVATE ws2_32)
-    endif ()
-
-    if (WIN32)
-      target_link_libraries(iwasm_static PRIVATE ntdll)
-    endif()
+target_link_libraries (vmlib PUBLIC ${LLVM_AVAILABLE_LIBS} ${UV_A_LIBS} -lm -ldl ${CMAKE_THREAD_LIBS_INIT})
+if (WAMR_BUILD_WASM_CACHE EQUAL 1)
+  target_link_libraries(vmlib INTERFACE boringssl_crypto)
+endif ()
 
-    install (TARGETS iwasm_static ARCHIVE DESTINATION lib)
+if (MINGW)
+  target_link_libraries(vmlib INTERFACE -lWs2_32 -lwsock32)
+  target_link_libraries(vmlib PRIVATE ws2_32)
 endif ()
 
-# SHARED LIBRARY
-if (WAMR_BUILD_SHARED)
-    add_library (iwasm_shared SHARED ${WAMR_RUNTIME_LIB_SOURCE})
-    set_target_properties (iwasm_shared PROPERTIES OUTPUT_NAME iwasm)
-    target_include_directories(iwasm_shared INTERFACE ${WAMR_ROOT_DIR}/core/iwasm/include)
-    target_link_libraries (iwasm_shared INTERFACE ${LLVM_AVAILABLE_LIBS} ${UV_A_LIBS} -lm -ldl ${CMAKE_THREAD_LIBS_INIT})
-    if (WAMR_BUILD_WASM_CACHE EQUAL 1)
-      target_link_libraries(iwasm_shared INTERFACE boringssl_crypto)
-    endif ()
+if (WIN32)
+  target_link_libraries(vmlib PRIVATE ntdll)
+endif()
 
-    if (MINGW)
-      target_link_libraries(iwasm_shared INTERFACE -lWs2_32 -lwsock32)
-      target_link_libraries(iwasm_shared PRIVATE ws2_32)
-    endif ()
+set (WAMR_PUBLIC_HEADERS
+  ${WAMR_ROOT_DIR}/core/iwasm/include/wasm_c_api.h
+  ${WAMR_ROOT_DIR}/core/iwasm/include/wasm_export.h
+  ${WAMR_ROOT_DIR}/core/iwasm/include/lib_export.h
+)
+set_target_properties (vmlib PROPERTIES PUBLIC_HEADER "${WAMR_PUBLIC_HEADERS}")
 
-    if (WIN32)
-      target_link_libraries(iwasm_shared PRIVATE ntdll)
-    endif()
+set_version_info (vmlib)
 
-    install (TARGETS iwasm_shared LIBRARY DESTINATION lib)
-endif ()
+install (TARGETS vmlib
+  EXPORT iwasmTargets
+  LIBRARY DESTINATION lib
+  PUBLIC_HEADER DESTINATION include/iwasm
+)
 
-# HEADERS
-install (FILES
-    ${WAMR_ROOT_DIR}/core/iwasm/include/wasm_c_api.h
-    ${WAMR_ROOT_DIR}/core/iwasm/include/wasm_export.h
-    ${WAMR_ROOT_DIR}/core/iwasm/include/lib_export.h
-    DESTINATION include)
+install_iwasm_package ()

CODEOWNERS

@@ -22,7 +22,7 @@
 # If none of the later patterns match, assign to anyone. This team is the
 # parent of all the other teams and automatically includes everyone on those
 # teams.
-* @loganek @lum1n0us @no1wudi @wenyongh @xujuntwt95329 @yamt
+* @loganek @lum1n0us @no1wudi @TianlongLiang @wenyongh @xujuntwt95329 @yamt
 
 # Some parts of the project require more specialized knowledge. In those areas
 # we designate smaller groups who are more likely to be aware of who's working

README.md

@@ -58,8 +58,8 @@ The WAMR VMcore supports the following architectures:
 - XTENSA, MIPS, ARC
 
 The following platforms are supported, click each link below for how to build iwasm on that platform. Refer to [WAMR porting guide](./doc/port_wamr.md) for how to port WAMR to a new platform.
-- [Linux](./product-mini/README.md#linux),  [Linux SGX (Intel Software Guard Extension)](./doc/linux_sgx.md),  [MacOS](./product-mini/README.md#macos),  [Android](./product-mini/README.md#android), [Windows](./product-mini/README.md#windows), [Windows (MinGW)](./product-mini/README.md#mingw)
-- [Zephyr](./product-mini/README.md#zephyr),  [AliOS-Things](./product-mini/README.md#alios-things),  [VxWorks](./product-mini/README.md#vxworks), [NuttX](./product-mini/README.md#nuttx), [RT-Thread](./product-mini/README.md#RT-Thread), [ESP-IDF](./product-mini/README.md#esp-idf)
+- [Linux](./product-mini/README.md#linux),  [Linux SGX (Intel Software Guard Extension)](./doc/linux_sgx.md),  [MacOS](./product-mini/README.md#macos),  [Android](./product-mini/README.md#android), [Windows](./product-mini/README.md#windows), [Windows (MinGW, MSVC)](./product-mini/README.md#mingw)
+- [Zephyr](./product-mini/README.md#zephyr),  [AliOS-Things](./product-mini/README.md#alios-things),  [VxWorks](./product-mini/README.md#vxworks), [NuttX](./product-mini/README.md#nuttx), [RT-Thread](./product-mini/README.md#RT-Thread), [ESP-IDF(FreeRTOS)](./product-mini/README.md#esp-idf)
 
 
 ## Getting started

build-scripts/build_llvm.py

@@ -105,12 +105,23 @@ def build_llvm(llvm_dir, platform, backends, projects, use_clang=False, extra_fl
     experimental_backends = ["ARC", "Xtensa"]
     normal_backends = [s for s in backends if s not in experimental_backends]
 
+    experimental_backends = ["ARC", "Xtensa"]
+    normal_backends = [s for s in backends if s not in experimental_backends]
+
     LLVM_TARGETS_TO_BUILD = [
+        '-DLLVM_TARGETS_TO_BUILD:STRING="' + ";".join(normal_backends) + '"'
+        if normal_backends
         '-DLLVM_TARGETS_TO_BUILD:STRING="' + ";".join(normal_backends) + '"'
         if normal_backends
         else '-DLLVM_TARGETS_TO_BUILD:STRING="AArch64;ARM;Mips;RISCV;X86"'
     ]
 
+    # if not on ARC platform, but want to add expeirmental backend ARC as target
+    if platform != "ARC" and "ARC" in backends:
+        LLVM_TARGETS_TO_BUILD.extend(
+            LLVM_EXTRA_COMPILE_OPTIONS["arc"]
+        )
+
     # if not on ARC platform, but want to add expeirmental backend ARC as target
     if platform != "ARC" and "ARC" in backends: 
         LLVM_TARGETS_TO_BUILD.extend(
@@ -217,11 +228,11 @@ def repackage_llvm_windows(llvm_dir):
     if not packs_path:
         raise Exception("Didn't find any LLVM-* package")
         return
-    
+
     llvm_package_path = f"_CPack_Packages/win64/NSIS/{packs_path[0].name}"
     windows_package_dir = build_dir.joinpath(llvm_package_path).resolve()
 
-    # mv package dir outside of build 
+    # mv package dir outside of build
     shutil.move(str(windows_package_dir), str(llvm_dir))
     # rm -r build
     shutil.rmtree(str(build_dir))
@@ -231,7 +242,7 @@ def repackage_llvm_windows(llvm_dir):
     moved_package_dir = llvm_dir.joinpath(packs_path[0].name)
     for sub_dir in moved_package_dir.iterdir():
         shutil.move(str(sub_dir), str(build_dir))
-    moved_package_dir.rmdir()  
+    moved_package_dir.rmdir()
 
 def main():
     parser = argparse.ArgumentParser(description="build necessary LLVM libraries")
@@ -256,6 +267,7 @@ def main():
             "Xtensa",
         ],
         default=[],
+        default=[],
         help="identify LLVM supported backends, separate by space, like '--arch ARM Mips X86'",
     )
     parser.add_argument(