[WIP] Add CMake build system

.github/workflows/main.yml

@@ -58,21 +58,27 @@ jobs:
 
     - name: Build libc
       shell: bash
-      run: make -j4
+      run: |
+        cmake -DCMAKE_INSTALL_PREFIX=install-sysroot .
+        cmake --build . --target install
+        ctest
 
     - uses: actions/upload-artifact@v1
       with:
         # Upload the sysroot folder. Give it a name according to the OS it was built for.
         name: ${{ format( 'sysroot-{0}.tgz', matrix.os) }}
-        path: sysroot
+        path: install-sysroot
 
     - name: Build libc + threads
       # Only build the thread-capable wasi-libc in the latest supported Clang
       # version; the earliest version does not have all necessary builtins
       # (e.g., `__builtin_wasm_memory_atomic_notify`).
       if: matrix.clang_version != '10.0.0'
       shell: bash
-      run: make -j4 THREAD_MODEL=posix
+      run: |
+        cmake -DCMAKE_INSTALL_PREFIX=install-sysroot -DTHREAD_MODEL=posix .
+        cmake --build . --target install
+        ctest
 
   # Disable the headerstest job for now, while WASI transitions from the
   # witx snapshots to wit proposals, and we have a few manual edits to the

CMakeLists.txt

@@ -0,0 +1,32 @@
+cmake_minimum_required(VERSION 3.16.3)
+
+project(wasi-libc LANGUAGES C)
+
+enable_testing()
+
+if("${CMAKE_C_COMPILER}" MATCHES "(.*)clang(-[0-9]+)?$")
+  set(CMAKE_NM "${CMAKE_MATCH_1}llvm-nm${CMAKE_MATCH_2}")
+endif()
+
+find_package(Python COMPONENTS Interpreter REQUIRED)
+
+set(TARGET_TRIPLE wasm32-wasi)
+set(MULTIARCH_TRIPLE wasm32-wasi)
+
+set(CMAKE_C_COMPILER_TARGET ${TARGET_TRIPLE} CACHE STRING "The target to compile for")
+
+# note that pthread support is still a work-in-progress.
+set(THREAD_MODEL "single" CACHE STRING "single or posix")
+
+set(MALLOC_IMPL "dlmalloc" CACHE STRING "dlmalloc or none")
+
+option(BUILD_LIBC_TOP_HALF "Build libc top half" ON)
+
+# When the length is no larger than this threshold, we consider the
+# overhead of bulk memory opcodes to outweigh the performance benefit,
+# and fall back to the original musl implementation. See
+# https://github.com/WebAssembly/wasi-libc/pull/263 for relevant
+# discussion
+set(BULK_MEMORY_THRESHOLD "32" CACHE STRING "bulk memory threshold")
+
+add_subdirectory(cmake)