WASIP3 threading support

.github/workflows/main.yml

@@ -284,7 +284,7 @@ jobs:
     - name: Setup `wasmtime`
       uses: bytecodealliance/actions/wasmtime/setup@v1
       with:
-        version: "38.0.3"
+        version: "40.0.2"
     - name: Setup wasi-libc
       run: |
         cmake -S . -B build -G Ninja \

CMakeLists.txt

@@ -68,7 +68,8 @@ elseif(TARGET_TRIPLE MATCHES "-wasip2$")
   set(SHARED ON)
 elseif(TARGET_TRIPLE MATCHES "-wasip3$")
   set(WASI p3)
-  set(SHARED ON)
+  # TODO: wasip3_thread_start.s also uses non-position-independent code.
+  set(SHARED OFF)
 else()
   message(FATAL_ERROR "Unknown WASI target triple: ${TARGET_TRIPLE}")
 endif()
@@ -87,6 +88,9 @@ endif()
 if(TARGET_TRIPLE MATCHES "-threads$")
   set(THREADS ON)
   add_compile_options(-mthread-model posix -pthread -ftls-model=local-exec -matomics)
+elseif(TARGET_TRIPLE MATCHES "-wasip3$")
+  set(THREADS OFF)
+  add_compile_options(-mthread-model posix -pthread -ftls-model=local-exec -matomics)
 else()
   set(THREADS OFF)
   add_compile_options(-mthread-model single)

cmake/ba-download.cmake

@@ -15,11 +15,23 @@ function(ba_download target repo version)
   endif()
 
   if (CMAKE_HOST_SYSTEM_NAME STREQUAL "Darwin")
-    set(os macos)
+    if (target STREQUAL wkg)
+      set(os apple-darwin)
+    else()
+      set(os macos)
+    endif()
   elseif (CMAKE_HOST_SYSTEM_NAME STREQUAL "Linux")
-    set(os linux)
+    if (target STREQUAL wkg)
+      set(os unknown-linux-gnu)
+    else()
+      set(os linux)
+    endif()
   elseif (CMAKE_HOST_SYSTEM_NAME STREQUAL "Windows")
-    set(os windows)
+    if (target STREQUAL wkg)
+      set(os pc-windows-gnu)
+    else()  
+      set(os windows)
+    endif()
   else()
     set(os "UNKNOWN_OS")
     message(WARNING "Unsupported system ${CMAKE_HOST_SYSTEM_NAME} for ${target}")
@@ -34,20 +46,50 @@ function(ba_download target repo version)
     set(fmt tar.gz)
   endif()
 
-  if (target STREQUAL wit-bindgen OR target STREQUAL wasm-tools)
+  if (target STREQUAL wit-bindgen OR target STREQUAL wasm-tools OR target STREQUAL wkg)
     set(tag v${version})
   else()
     set(tag ${version})
   endif()
 
+
   message(STATUS "Using ${target} ${version} for ${arch}-${os} from ${repo}")
 
-  ExternalProject_Add(
-    ${target}
-    EXCLUDE_FROM_ALL ON
-    URL "${repo}/releases/download/${tag}/${target}-${version}-${arch}-${os}.${fmt}"
-    CONFIGURE_COMMAND ""
-    BUILD_COMMAND ""
-    INSTALL_COMMAND ""
-  )
+  if (target STREQUAL wkg)
+    # wkg ships a single binary rather than an archive
+    if (CMAKE_HOST_SYSTEM_NAME STREQUAL "Windows")
+      set(download_name "${target}-${arch}-${os}.exe")
+    else()
+      set(download_name "${target}-${arch}-${os}")
+    endif()
+    ExternalProject_Add(
+      ${target}
+      EXCLUDE_FROM_ALL ON
+      URL "${repo}/releases/download/${tag}/${target}-${arch}-${os}"
+      DOWNLOAD_NO_EXTRACT ON
+      DOWNLOAD_NAME ${download_name}
+      CONFIGURE_COMMAND ""
+      BUILD_COMMAND ""
+      INSTALL_COMMAND ""
+    )
+
+    # Make the binary executable on Unix-like systems
+    if (NOT CMAKE_HOST_SYSTEM_NAME STREQUAL "Windows")
+      ExternalProject_Add_Step(
+        ${target} chmod-executable
+        COMMAND chmod +x <DOWNLOADED_FILE>
+        DEPENDEES download
+        DEPENDERS build
+      )
+    endif()
+  else()
+    ExternalProject_Add(
+      ${target}
+      EXCLUDE_FROM_ALL ON
+      URL "${repo}/releases/download/${tag}/${target}-${version}-${arch}-${os}.${fmt}"
+      CONFIGURE_COMMAND ""
+      BUILD_COMMAND ""
+      INSTALL_COMMAND ""
+    )
+  endif()
 endfunction()

cmake/bindings.cmake

@@ -4,6 +4,8 @@ if (NOT BINDINGS_TARGET)
   return()
 endif()
 
+include(ExternalProject)
+
 # If `wit-bindgen` is on the system and has the right version, favor that,
 # otherwise download a known good version.
 find_program(WIT_BINDGEN_EXECUTABLE NAMES wit-bindgen)
@@ -15,8 +17,8 @@ if(WIT_BINDGEN_EXECUTABLE)
     OUTPUT_VARIABLE WIT_BINDGEN_VERSION
     OUTPUT_STRIP_TRAILING_WHITESPACE)
 
-  if (NOT (WIT_BINDGEN_VERSION MATCHES "0\\.48\\.0"))
-    message(WARNING "wit-bindgen version 0.48.0 is required, found: ${WIT_BINDGEN_VERSION}")
+  if (NOT (WIT_BINDGEN_VERSION MATCHES "0\\.51\\.0"))
+    message(WARNING "wit-bindgen version 0.51.0 is required, found: ${WIT_BINDGEN_VERSION}")
     set(WIT_BINDGEN_EXECUTABLE "")
   endif()
 endif()
@@ -26,7 +28,7 @@ if (NOT WIT_BINDGEN_EXECUTABLE)
   ba_download(
     wit-bindgen
     "https://github.com/bytecodealliance/wit-bindgen"
-    "0.48.0"
+    "0.51.0"
   )
   ExternalProject_Get_Property(wit-bindgen SOURCE_DIR)
   set(wit_bindgen "${SOURCE_DIR}/wit-bindgen")
@@ -35,101 +37,139 @@ else()
   set(wit_bindgen ${WIT_BINDGEN_EXECUTABLE})
 endif()
 
-include(ExternalProject)
-set(p2 0.2.0)
-ExternalProject_Add(
-  wasip2-wits
-  URL https://github.com/WebAssembly/wasi-cli/archive/refs/tags/v${p2}.tar.gz
-  CONFIGURE_COMMAND ""
-  BUILD_COMMAND ""
-  INSTALL_COMMAND ""
-  EXCLUDE_FROM_ALL TRUE
-)
-ExternalProject_Get_Property(wasip2-wits SOURCE_DIR)
-set(wasip2_wit_dir ${SOURCE_DIR}/wit)
+# If `wkg` is on the system and has the right version, favor that,
+# otherwise download a known good version.
+find_program(WKG_EXECUTABLE NAMES wkg)
+if(WKG_EXECUTABLE)
+  message(STATUS "Found wkg: ${WKG_EXECUTABLE}")
+
+  execute_process(
+    COMMAND ${WKG_EXECUTABLE} --version
+    OUTPUT_VARIABLE WKG_VERSION
+    OUTPUT_STRIP_TRAILING_WHITESPACE)
+
+  if (NOT (WKG_VERSION MATCHES "0\\.13\\.0"))
+    message(WARNING "wkg version 0.13.0 is required, found: ${WKG_VERSION}")
+    set(WKG_EXECUTABLE "")
+  endif()
+endif()
+
+if (NOT WKG_EXECUTABLE)
+  include(ba-download)
+  ba_download(
+    wkg
+    "https://github.com/bytecodealliance/wasm-pkg-tools"
+    "0.13.0"
+  )
+  ExternalProject_Get_Property(wkg DOWNLOADED_FILE)
+  set(wkg_bin ${DOWNLOADED_FILE})
+else()
+  add_custom_target(wkg)
+  set(wkg_bin ${WKG_EXECUTABLE})
+endif()
+
 set(bottom_half "${CMAKE_SOURCE_DIR}/libc-bottom-half")
 
+set(wasip2_wit_dir ${CMAKE_CURRENT_BINARY_DIR}/wasi/p2/wit)
+set(wasip2-version 0.2.0)
+file(MAKE_DIRECTORY ${wasip2_wit_dir})
+configure_file(${CMAKE_SOURCE_DIR}/wasi/wasi-libc-wasip2.wit.in ${wasip2_wit_dir}/wasi-libc-wasip2.wit)
+set(wasip2_stamp ${CMAKE_CURRENT_BINARY_DIR}/wasi/p2/.wit-fetch-stamp)
+add_custom_command(
+  OUTPUT ${wasip2_stamp}
+  COMMAND ${CMAKE_COMMAND} -E make_directory ${CMAKE_CURRENT_BINARY_DIR}/wasi/p2
+  COMMAND ${wkg_bin} wit fetch
+  COMMAND ${CMAKE_COMMAND} -E touch ${wasip2_stamp}
+  WORKING_DIRECTORY ${wasip2_wit_dir}/..
+  DEPENDS wkg ${wasip2_wit_dir}/wasi-libc-wasip2.wit
+  COMMENT "Fetching WASI P2 dependencies"
+)
+add_custom_target(wasip2-wits DEPENDS ${wasip2_stamp})
 add_custom_target(
   bindings-p2
   COMMAND
     ${wit_bindgen} c
       --autodrop-borrows yes
       --rename-world wasip2
       --type-section-suffix __wasi_libc
-      --world wasi:cli/imports@${p2}
-      --rename wasi:clocks/monotonic-clock@${p2}=monotonic_clock
-      --rename wasi:clocks/wall-clock@${p2}=wall_clock
-      --rename wasi:filesystem/preopens@${p2}=filesystem_preopens
-      --rename wasi:filesystem/types@${p2}=filesystem
-      --rename wasi:io/error@${p2}=io_error
-      --rename wasi:io/poll@${p2}=poll
-      --rename wasi:io/streams@${p2}=streams
-      --rename wasi:random/insecure-seed@${p2}=random_insecure_seed
-      --rename wasi:random/insecure@${p2}=random_insecure
-      --rename wasi:random/random@${p2}=random
-      --rename wasi:sockets/instance-network@${p2}=instance_network
-      --rename wasi:sockets/ip-name-lookup@${p2}=ip_name_lookup
-      --rename wasi:sockets/network@${p2}=network
-      --rename wasi:sockets/tcp-create-socket@${p2}=tcp_create_socket
-      --rename wasi:sockets/tcp@${p2}=tcp
-      --rename wasi:sockets/udp-create-socket@${p2}=udp_create_socket
-      --rename wasi:sockets/udp@${p2}=udp
-      --rename wasi:cli/environment@${p2}=environment
-      --rename wasi:cli/exit@${p2}=exit
-      --rename wasi:cli/stdin@${p2}=stdin
-      --rename wasi:cli/stdout@${p2}=stdout
-      --rename wasi:cli/stderr@${p2}=stderr
-      --rename wasi:cli/terminal-input@${p2}=terminal_input
-      --rename wasi:cli/terminal-output@${p2}=terminal_output
-      --rename wasi:cli/terminal-stdin@${p2}=terminal_stdin
-      --rename wasi:cli/terminal-stdout@${p2}=terminal_stdout
-      --rename wasi:cli/terminal-stderr@${p2}=terminal_stderr
+      --world wasi:cli/imports@${wasip2-version}
+      --rename wasi:clocks/monotonic-clock@${wasip2-version}=monotonic_clock
+      --rename wasi:clocks/wall-clock@${wasip2-version}=wall_clock
+      --rename wasi:filesystem/preopens@${wasip2-version}=filesystem_preopens
+      --rename wasi:filesystem/types@${wasip2-version}=filesystem
+      --rename wasi:io/error@${wasip2-version}=io_error
+      --rename wasi:io/poll@${wasip2-version}=poll
+      --rename wasi:io/streams@${wasip2-version}=streams
+      --rename wasi:random/insecure-seed@${wasip2-version}=random_insecure_seed
+      --rename wasi:random/insecure@${wasip2-version}=random_insecure
+      --rename wasi:random/random@${wasip2-version}=random
+      --rename wasi:sockets/instance-network@${wasip2-version}=instance_network
+      --rename wasi:sockets/ip-name-lookup@${wasip2-version}=ip_name_lookup
+      --rename wasi:sockets/network@${wasip2-version}=network
+      --rename wasi:sockets/tcp-create-socket@${wasip2-version}=tcp_create_socket
+      --rename wasi:sockets/tcp@${wasip2-version}=tcp
+      --rename wasi:sockets/udp-create-socket@${wasip2-version}=udp_create_socket
+      --rename wasi:sockets/udp@${wasip2-version}=udp
+      --rename wasi:cli/environment@${wasip2-version}=environment
+      --rename wasi:cli/exit@${wasip2-version}=exit
+      --rename wasi:cli/stdin@${wasip2-version}=stdin
+      --rename wasi:cli/stdout@${wasip2-version}=stdout
+      --rename wasi:cli/stderr@${wasip2-version}=stderr
+      --rename wasi:cli/terminal-input@${wasip2-version}=terminal_input
+      --rename wasi:cli/terminal-output@${wasip2-version}=terminal_output
+      --rename wasi:cli/terminal-stdin@${wasip2-version}=terminal_stdin
+      --rename wasi:cli/terminal-stdout@${wasip2-version}=terminal_stdout
+      --rename wasi:cli/terminal-stderr@${wasip2-version}=terminal_stderr
       ${wasip2_wit_dir}
   COMMAND cmake -E copy wasip2.h ${bottom_half}/headers/public/wasi/__generated_wasip2.h
   COMMAND cmake -E copy wasip2_component_type.o ${bottom_half}/sources
   COMMAND cmake -E copy wasip2.c ${bottom_half}/sources
-  DEPENDS wit-bindgen wasip2-wits
+  DEPENDS wit-bindgen wkg wasip2-wits
 )
 
-set(p3 0.3.0-rc-2025-09-16)
-ExternalProject_Add(
-  wasip3-wits
-  URL https://github.com/WebAssembly/wasi-cli/archive/refs/tags/v${p3}.tar.gz
-  CONFIGURE_COMMAND ""
-  BUILD_COMMAND ""
-  INSTALL_COMMAND ""
-  EXCLUDE_FROM_ALL TRUE
+set(wasip3_wit_dir ${CMAKE_CURRENT_BINARY_DIR}/wasi/p3/wit)
+set(wasip3-version 0.3.0-rc-2026-01-06)
+file(MAKE_DIRECTORY ${wasip3_wit_dir})
+configure_file(${CMAKE_SOURCE_DIR}/wasi/wasi-libc-wasip3.wit.in ${wasip3_wit_dir}/wasi-libc-wasip3.wit)
+set(wasip3_stamp ${CMAKE_CURRENT_BINARY_DIR}/wasi/p3/.wit-fetch-stamp)
+add_custom_command(
+  OUTPUT ${wasip3_stamp}
+  COMMAND ${CMAKE_COMMAND} -E make_directory ${CMAKE_CURRENT_BINARY_DIR}/wasi/p3
+  COMMAND ${wkg_bin} wit fetch
+  COMMAND ${CMAKE_COMMAND} -E touch ${wasip3_stamp}
+  WORKING_DIRECTORY ${wasip3_wit_dir}/..
+  DEPENDS wkg ${wasip3_wit_dir}/wasi-libc-wasip3.wit
+  COMMENT "Fetching WASI P3 dependencies"
 )
-ExternalProject_Get_Property(wasip3-wits SOURCE_DIR)
-set(wasip3_wit_dir ${SOURCE_DIR}/wit-0.3.0-draft)
-
+add_custom_target(wasip3-wits DEPENDS ${wasip3_stamp})
 add_custom_target(
   bindings-p3
   COMMAND
     ${wit_bindgen} c
+      --generate-threading-helpers
       --autodrop-borrows yes
       --rename-world wasip3
       --type-section-suffix __wasi_libc
-      --world wasi:cli/imports@${p3}
-      --rename wasi:clocks/monotonic-clock@${p3}=monotonic_clock
-      --rename wasi:clocks/wall-clock@${p3}=wall_clock
-      --rename wasi:filesystem/preopens@${p3}=filesystem_preopens
-      --rename wasi:filesystem/types@${p3}=filesystem
-      --rename wasi:random/insecure-seed@${p3}=random_insecure_seed
-      --rename wasi:random/insecure@${p3}=random_insecure
-      --rename wasi:random/random@${p3}=random
-      --rename wasi:sockets/types@${p3}=sockets
-      --rename wasi:sockets/ip-name-lookup@${p3}=ip_name_lookup
-      --rename wasi:cli/environment@${p3}=environment
-      --rename wasi:cli/exit@${p3}=exit
-      --rename wasi:cli/stdin@${p3}=stdin
-      --rename wasi:cli/stdout@${p3}=stdout
-      --rename wasi:cli/stderr@${p3}=stderr
-      --rename wasi:cli/terminal-input@${p3}=terminal_input
-      --rename wasi:cli/terminal-output@${p3}=terminal_output
-      --rename wasi:cli/terminal-stdin@${p3}=terminal_stdin
-      --rename wasi:cli/terminal-stdout@${p3}=terminal_stdout
-      --rename wasi:cli/terminal-stderr@${p3}=terminal_stderr
+      --world wasi:cli/imports@${wasip3-version}
+      --rename wasi:clocks/monotonic-clock@${wasip3-version}=monotonic_clock
+      --rename wasi:clocks/system-clock@${wasip3-version}=system_clock
+      --rename wasi:filesystem/preopens@${wasip3-version}=filesystem_preopens
+      --rename wasi:filesystem/types@${wasip3-version}=filesystem
+      --rename wasi:random/insecure-seed@${wasip3-version}=random_insecure_seed
+      --rename wasi:random/insecure@${wasip3-version}=random_insecure
+      --rename wasi:random/random@${wasip3-version}=random
+      --rename wasi:sockets/types@${wasip3-version}=sockets
+      --rename wasi:sockets/ip-name-lookup@${wasip3-version}=ip_name_lookup
+      --rename wasi:cli/environment@${wasip3-version}=environment
+      --rename wasi:cli/exit@${wasip3-version}=exit
+      --rename wasi:cli/stdin@${wasip3-version}=stdin
+      --rename wasi:cli/stdout@${wasip3-version}=stdout
+      --rename wasi:cli/stderr@${wasip3-version}=stderr
+      --rename wasi:cli/terminal-input@${wasip3-version}=terminal_input
+      --rename wasi:cli/terminal-output@${wasip3-version}=terminal_output
+      --rename wasi:cli/terminal-stdin@${wasip3-version}=terminal_stdin
+      --rename wasi:cli/terminal-stdout@${wasip3-version}=terminal_stdout
+      --rename wasi:cli/terminal-stderr@${wasip3-version}=terminal_stderr
       ${wasip3_wit_dir}
   COMMAND cmake -E copy wasip3.h ${bottom_half}/headers/public/wasi/__generated_wasip3.h
   COMMAND cmake -E copy wasip3_component_type.o ${bottom_half}/sources
@@ -139,12 +179,18 @@ add_custom_target(
 
 add_custom_target(bindings DEPENDS bindings-p2 bindings-p3)
 
+if(CMAKE_HOST_SYSTEM_NAME STREQUAL "Darwin")
+  set(SED_INPLACE_ARGS -i '')
+else()
+  set(SED_INPLACE_ARGS -i)
+endif()
+
 function(wit_bindgen_edit p)
   add_custom_target(
     bindings-${p}-edit
-    COMMAND sed -i "" "'s_#include .wasi${p}\.h._#include \"wasi/wasi${p}.h\"_'" ${bottom_half}/sources/wasi${p}.c
-    COMMAND sed -i "" "s/extern void exit_exit/_Noreturn extern void exit_exit/" ${bottom_half}/headers/public/wasi/__generated_wasi${p}.h
-    COMMAND sed -i "" "s/extern void __wasm_import_exit_exit/_Noreturn extern void __wasm_import_exit_exit/" ${bottom_half}/sources/wasi${p}.c
+    COMMAND sed ${SED_INPLACE_ARGS} "'s_#include .wasi${p}\.h._#include \"wasi/wasi${p}.h\"_'" ${bottom_half}/sources/wasi${p}.c
+    COMMAND sed ${SED_INPLACE_ARGS} "s/extern void exit_exit/_Noreturn extern void exit_exit/" ${bottom_half}/headers/public/wasi/__generated_wasi${p}.h
+    COMMAND sed ${SED_INPLACE_ARGS} "s/extern void __wasm_import_exit_exit/_Noreturn extern void __wasm_import_exit_exit/" ${bottom_half}/sources/wasi${p}.c
     DEPENDS bindings-${p}
   )
   add_dependencies(bindings bindings-${p}-edit)

expected/wasm32-wasip2/defined-symbols.txt

@@ -1504,6 +1504,7 @@ wasip2_list_u32_free
 wasip2_list_u8_free
 wasip2_option_string_free
 wasip2_string_dup
+wasip2_string_dup_n
 wasip2_string_free
 wasip2_string_from_c
 wasip2_string_set