feat(wasi): add wasm32-wasi as a compile target

.github/actions/wasi/base/action.yml

@@ -0,0 +1,16 @@
+name: "Ubuntu base dependencies"
+
+runs:
+  using: "composite"
+  steps:
+    - name: Install system dependencies
+      shell: bash
+      run: |
+        sudo apt-get update
+        sudo apt-get install -y ninja-build
+
+    - name: Install wasmtime CLI
+      shell: bash
+      run: |
+        curl https://wasmtime.dev/install.sh -sSf | bash
+        sudo cp ~/.wasmtime/bin/wasmtime /usr/bin/wasmtime

.github/actions/wasi/clang/action.yml

@@ -0,0 +1,15 @@
+name: "Ubuntu latest clang"
+
+runs:
+  using: "composite"
+  steps:
+    - name: Install clang/llvm 17
+      shell: bash
+      run: |
+        sudo apt-add-repository 'deb https://apt.llvm.org/jammy llvm-toolchain-jammy-17 main'
+        sudo wget -qO /etc/apt/trusted.gpg.d/llvm.asc https://apt.llvm.org/llvm-snapshot.gpg.key
+        sudo apt-get update
+        sudo apt-get install -y -t llvm-toolchain-jammy-17 \
+            clang-17 llvm-17 lld-17 lldb-17 libc++-17-dev \
+            libc++abi-17-dev libclang-rt-17-dev
+        for f in /usr/lib/llvm-*/bin/*; do sudo ln -sf "$f" /usr/bin; done

.github/ci.yaml

@@ -16,6 +16,7 @@ jobs:
           { os: macos-latest, preset: x64-darwin-clang-dynamic },
           { os: windows-latest, preset: x64-windows-msvc-dynamic },
           { os: windows-latest, preset: x64-windows-clang-dynamic },
+          { os: ubuntu-latest, preset: wasm32-wasi-clang-static },
         ]
 
     steps:
@@ -31,3 +32,11 @@ jobs:
       shell: bash
       run: |
         cmake --workflow --preset ${{matrix.target.preset}}
+
+    - name: Upload vcpkg error logs
+      if: failure()
+      uses: actions/upload-artifact@v4
+      with:
+        name: logs-${{matrix.target.preset}}
+        path: |
+          /usr/local/share/vcpkg/**/*.log

.github/workflows/ci.yaml

@@ -12,11 +12,11 @@ jobs:
           { os: ubuntu-latest, preset: x64-linux-gcc-dynamic },
           { os: ubuntu-latest, preset: x86-linux-gcc-dynamic },
           { os: ubuntu-latest, preset: x64-linux-clang-dynamic },
-          { os: ubuntu-latest, preset: x86-linux-clang-dynamic },
           { os: macos-latest, preset: x64-darwin-gcc-dynamic },
           { os: macos-latest, preset: x64-darwin-clang-dynamic },
           { os: windows-latest, preset: x64-windows-msvc-dynamic },
           { os: windows-latest, preset: x64-windows-clang-dynamic },
+          { os: ubuntu-latest, preset: wasm32-wasi-clang-static },
         ]
 
     steps:
@@ -37,3 +37,11 @@ jobs:
       shell: bash
       run: |
         cmake --workflow --preset ${{matrix.target.preset}}
+
+    - name: Upload vcpkg error logs
+      if: failure()
+      uses: actions/upload-artifact@v4
+      with:
+        name: logs-${{matrix.target.preset}}
+        path: |
+          /usr/local/share/vcpkg/**/*.log

CMakePresets.json

@@ -8,6 +8,7 @@
   "include": [
     "cmake/presets/arm64-darwin-gcc.json",
     "cmake/presets/arm64-darwin-clang.json",
+    "cmake/presets/wasm32-wasi-clang.json",
     "cmake/presets/x64-darwin-gcc.json",
     "cmake/presets/x64-darwin-clang.json",
     "cmake/presets/x64-linux-gcc.json",

README.md

@@ -62,4 +62,18 @@ find_package(<PROJECT_NAME> CONFIG REQUIRED)
 target_link_libraries(<TARGET> PUBLIC <PROJECT_NAME>::<MODULE_NAME>)
 ```
 
-This will require that your library is published and installed via vcpkg or found locally by setting the `CMAKE_PREFIX_PATH` environment variable in your other project during configure.
+This will require that your library is published and installed via vcpkg or found locally by setting the `CMAKE_PREFIX_PATH` environment variable in your other project during configure.
+
+If you wish to expose parts of your library as a WebAssembly module, you can add the `extern "C" __attribute__((export_name("<my_function_name>")))` annotation to any function you wish to expose in `src/wasm/interface.cpp`, and compile using the `wasm32-wasi-clang` preset. This will generate a minimal WebAssembly binary exposing your exported functions at `build/<PRESET>/src/wasm/<Debug|Release|RelWithDebInfo>/lib<PROJECT_NAME>.wasm`. This binary conforms to the [WASI WebAssembly standard](https://wasi.dev/), so it can be utilized in any WASI-supporting runtime like [`wasmer.io`](https://wasmer.io/) or [wasmtime](https://wasmtime.dev/).
+
+A WebAssembly version of your CLI will also be available:
+
+```sh
+wasmtime run build/<PRESET>/src/cli/<Debug|Release|RelWithDebInfo>/<PROJECT_NAME>_cli
+
+# Prints:
+# <PROJECT_NAME> version: 0.0.1
+```
+
+> [!NOTE] 
+> Exposed WebAssembly functions currently only accept parameters and return values of numerical type. This is how core WebAssembly files work, and without additional glue-code or binding generators like [wit-bindgen](https://github.com/bytecodealliance/wit-bindgen), complex data-types cannot be sent over the runtime's ABI boundary. Complex data must be transferred via pointer and serialized bytes in exported/shared memory.

cmake/presets/toolchains/wasi-sdk.json

@@ -0,0 +1,13 @@
+{
+  "version": 6,
+  "configurePresets": [
+    {
+      "name": "wasi-sdk",
+      "hidden": true,
+      "cacheVariables": {
+        "VCPKG_CHAINLOAD_TOOLCHAIN_FILE": "${sourceDir}/cmake/toolchains/wasi-sdk.toolchain.cmake",
+        "CMAKE_CROSSCOMPILING_EMULATOR": "wasmtime"
+      }
+    }
+  ]
+}

cmake/presets/wasm32-wasi-clang.json

@@ -0,0 +1,52 @@
+{
+  "version": 6,
+  "include": [
+    "base.json",
+    "compilers/clang.json",
+    "toolchains/wasi-sdk.json"
+  ],
+  "configurePresets": [
+    {
+      "name": "wasm32-wasi-clang-static",
+      "inherits": [
+        "base",
+        "wasi-sdk",
+        "clang"
+      ],
+      "displayName": "WASM32 WASI clang static libs"
+    }
+  ],
+  "buildPresets": [
+    {
+      "name": "wasm32-wasi-clang-static",
+      "inherits": "base",
+      "configurePreset": "wasm32-wasi-clang-static"
+    }
+  ],
+  "testPresets": [
+    {
+      "name": "wasm32-wasi-clang-static",
+      "inherits": "base",
+      "configurePreset": "wasm32-wasi-clang-static"
+    }
+  ],
+  "workflowPresets": [
+    {
+      "name": "wasm32-wasi-clang-static",
+      "steps": [
+        {
+          "type": "configure",
+          "name": "wasm32-wasi-clang-static"
+        },
+        {
+          "type": "build",
+          "name": "wasm32-wasi-clang-static"
+        },
+        {
+          "type": "test",
+          "name": "wasm32-wasi-clang-static"
+        }
+      ]
+    }
+  ]
+}

cmake/toolchains/wasi-sdk.toolchain.cmake

@@ -0,0 +1,14 @@
+include(FetchContent)
+
+set(FETCHCONTENT_FULLY_DISCONNECTED_OLD ${FETCHCONTENT_FULLY_DISCONNECTED})
+set(FETCHCONTENT_FULLY_DISCONNECTED OFF)
+FetchContent_Declare(
+  wasi_sdk_toolchain
+  SOURCE_DIR "${CMAKE_BINARY_DIR}/_deps/wasi-sdk"
+  GIT_REPOSITORY https://github.com/rioam2/wasi-sdk-toolchain.git
+  GIT_TAG wasi-sdk-23
+)
+FetchContent_MakeAvailable(wasi_sdk_toolchain)
+set(FETCHCONTENT_FULLY_DISCONNECTED ${FETCHCONTENT_FULLY_DISCONNECTED_OLD})
+
+include("${wasi_sdk_toolchain_SOURCE_DIR}/wasi-sdk.toolchain.cmake")

cmake/vcpkg/triplets/wasm32-wasi.cmake

@@ -0,0 +1,9 @@
+set(VCPKG_TARGET_ARCHITECTURE wasm32)
+set(VCPKG_LIBRARY_LINKAGE static)
+set(VCPKG_CRT_LINKAGE static)
+
+set(VCPKG_CMAKE_SYSTEM_NAME WASI)
+set(VCPKG_CMAKE_SYSTEM_VERSION 1)
+set(VCPKG_CMAKE_SYSTEM_PROCESSOR wasm32)
+
+set(VCPKG_CHAINLOAD_TOOLCHAIN_FILE "${CMAKE_CURRENT_LIST_DIR}/../../toolchains/wasi-sdk.toolchain.cmake")

cmake/vcpkg/vcpkg.toolchain.cmake

@@ -17,8 +17,8 @@ include(${CMAKE_CURRENT_LIST_DIR}/bootstrap/vcpkg-config.cmake)
 
 vcpkg_configure(
   CACHE_DIR_NAME @cpp_pt_name@
-  REPO https://github.com/microsoft/vcpkg.git
-  REF 9edb1b8e590cc086563301d735cae4b6e732d2d2 # release 2023.08.09
+  REPO https://github.com/rioam2/vcpkg-wasm32-wasi
+  REF 983e077b814c4c0e56336e1d32407c2b2c13a90b
 )
 
 include($CACHE{_VCPKG_TOOLCHAIN_FILE})

init.cmake

@@ -65,6 +65,8 @@ set(templates
     src/${cpp_pt_module}/src/header-1.cpp
     src/cli/CMakeLists.txt
     src/cli/src/main.cpp
+    src/wasm/CMakeLists.txt
+    src/wasm/src/interface.cpp
     src/cmake/add_cpp_pt_executable.cmake
     src/cmake/add_cpp_pt_module.cmake
     src/cmake/cpp-pt-config.cmake

src/CMakeLists.txt

@@ -17,3 +17,7 @@ include(add_@cpp_pt_cmake@_executable)
 
 add_subdirectory(@cpp_pt_module@)
 add_subdirectory(cli)
+
+if (WASI) 
+  add_subdirectory(wasm)
+endif()

src/wasm/CMakeLists.txt

@@ -0,0 +1,16 @@
+# SPDX-FileCopyrightText: Copyright 2023 Mikhail Svetkin
+# SPDX-License-Identifier: MIT
+
+add_@cpp_pt_cmake@_executable(wasm)
+
+target_sources(${@cpp_pt_cmake@_executable_target} PRIVATE 
+  src/interface.cpp
+)
+
+target_link_libraries(${@cpp_pt_cmake@_executable_target}
+  PRIVATE
+    @cpp_pt_name@::@cpp_pt_module@
+)
+
+set_target_properties(${@cpp_pt_cmake@_executable_target} PROPERTIES OUTPUT_NAME "lib@cpp_pt_module@.wasm")
+target_link_options(${@cpp_pt_cmake@_executable_target} PRIVATE -nostartfiles -Wl,--no-entry)

src/wasm/src/interface.cpp

@@ -0,0 +1,35 @@
+#include "@cpp_pt_name@/@cpp_pt_module@/@cpp_pt_module_header@.hpp"
+
+#include <fmt/core.h>
+
+#include <cstdlib>
+#include <cstring>
+#include <string>
+
+// Memory management exports
+extern "C" __attribute__((export_name("wasm_malloc"))) void* wasm_malloc(size_t nbytes) {
+  return std::malloc(nbytes);
+}
+
+extern "C" __attribute__((export_name("wasm_free"))) void wasm_free(
+    void* ptr) {
+  return std::free(ptr);
+}
+
+// Exported WASM functions
+extern "C" __attribute__((export_name("version"))) uint8_t* version() {
+  std::string version = @cpp_pt_name@::@cpp_pt_module@::version();
+  uint8_t* versionPointer = (uint8_t*)wasm_malloc(version.length());
+  std::memcpy(versionPointer, version.c_str(), version.length());
+  return versionPointer;
+}
+
+// This is the WASM module's initialization entrypoint. It should be called
+// before running any other exported function because it initializes implicit
+// global/static resources. This is only required in library/reactor mode of
+// WebAssembly. Read more here:
+// https://wasmcloud.com/blog/webassembly-patterns-command-reactor-library#the-reactor-pattern
+extern "C" void __wasm_call_ctors();
+extern "C" __attribute__((export_name("_start"))) void _start() {
+  __wasm_call_ctors();
+}

tests/cmake/add_cpp_pt_test.cmake

@@ -25,5 +25,9 @@ function(add_@cpp_pt_cmake@_test test_name)
     ${test_target} PRIVATE @cpp_pt_name@::${module_name} Catch2::Catch2WithMain
   )
 
+  if (WASI)
+    target_link_options(${test_target} PRIVATE -nostartfiles -Wl,--no-entry)
+  endif()
+
   catch_discover_tests(${test_target} TEST_PREFIX "${test_target}:" ${ARGN})
 endfunction()