WebAssembly · alexcrichton · Dec 18, 2025 · Dec 18, 2025 · Dec 23, 2025 · Dec 23, 2025
diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
@@ -122,6 +122,19 @@ jobs:
             test: true
             args: -DCMAKE_BUILD_TYPE=Debug -DTARGET_TRIPLE=wasm32-wasip1-threads
 
+          - name: Test wasm32-wasip3
+            os: ubuntu-24.04
+            clang_version: 19
+            test: true
+            upload: wasm32-wasip3
+            args: -DTARGET_TRIPLE=wasm32-wasip3
+
+          - name: Test wasm32-wasip3 (debug)
+            os: ubuntu-24.04
+            clang_version: 19
+            test: true
+            args: -DCMAKE_BUILD_TYPE=Debug -DTARGET_TRIPLE=wasm32-wasip3
+
           - name: Test emmalloc
             os: ubuntu-24.04
             clang_version: 19

diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -64,8 +64,9 @@ elseif(TARGET_TRIPLE MATCHES "-wasip1$")
   set(SHARED ON)
 elseif(TARGET_TRIPLE MATCHES "-wasip2$")
   set(WASI p2)
-  set(__wasilibc_use_wasip2 ON)
-  add_compile_definitions(-D__wasilibc_use_wasip2)
+  set(SHARED ON)
+elseif(TARGET_TRIPLE MATCHES "-wasip3$")
+  set(WASI p3)
   set(SHARED ON)
 else()
   message(FATAL_ERROR "Unknown WASI target triple: ${TARGET_TRIPLE}")
@@ -129,6 +130,16 @@ if(SIMD)
     -D__wasilibc_simd_string)
 endif()
 
+if(WASI STREQUAL "p1")
+  set(__wasip1__ ON)
+elseif(WASI STREQUAL "p2")
+  set(__wasip2__ ON)
+elseif(WASI STREQUAL "p3")
+  set(__wasip3__ ON)
+else()
+  message(FATAL_ERROR "Unknown WASI version: ${WASI}")
+endif()
+
 include(bindings)
 include(builtins)
 if (NOT (WASI STREQUAL "p1"))
@@ -302,6 +313,8 @@ endif()
 # here since I can't figure out anything else that works for now.
 if (WASI STREQUAL "p2")
   set(libc_extra_objects libc-bottom-half/sources/wasip2_component_type.o)
+elseif (WASI STREQUAL "p3")
+  set(libc_extra_objects libc-bottom-half/sources/wasip3_component_type.o)
 endif()
 
 add_library(c SHARED EXCLUDE_FROM_ALL

diff --git a/cmake/bindings.cmake b/cmake/bindings.cmake
@@ -8,59 +8,119 @@ ba_download(
 ExternalProject_Get_Property(wit-bindgen SOURCE_DIR)
 set(wit_bindgen "${SOURCE_DIR}/wit-bindgen")
 
+set(p2 0.2.0)
 ExternalProject_Add(
-  wasi-wits
-  URL https://github.com/WebAssembly/wasi-cli/archive/refs/tags/v0.2.0.tar.gz
+  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(wasi-wits SOURCE_DIR)
-set(wit_dir ${SOURCE_DIR}/wit)
+ExternalProject_Get_Property(wasip2-wits SOURCE_DIR)
+set(wasip2_wit_dir ${SOURCE_DIR}/wit)
 set(bottom_half "${CMAKE_SOURCE_DIR}/libc-bottom-half")
 
 add_custom_target(
-  bindings
+  bindings-p2
   COMMAND
     ${wit_bindgen} c
       --autodrop-borrows yes
       --rename-world wasip2
       --type-section-suffix __wasi_libc
-      --world wasi:cli/imports@0.2.0
-      --rename wasi:clocks/monotonic-clock@0.2.0=monotonic_clock
-      --rename wasi:clocks/wall-clock@0.2.0=wall_clock
-      --rename wasi:filesystem/preopens@0.2.0=filesystem_preopens
-      --rename wasi:filesystem/types@0.2.0=filesystem
-      --rename wasi:io/error@0.2.0=io_error
-      --rename wasi:io/poll@0.2.0=poll
-      --rename wasi:io/streams@0.2.0=streams
-      --rename wasi:random/insecure-seed@0.2.0=random_insecure_seed
-      --rename wasi:random/insecure@0.2.0=random_insecure
-      --rename wasi:random/random@0.2.0=random
-      --rename wasi:sockets/instance-network@0.2.0=instance_network
-      --rename wasi:sockets/ip-name-lookup@0.2.0=ip_name_lookup
-      --rename wasi:sockets/network@0.2.0=network
-      --rename wasi:sockets/tcp-create-socket@0.2.0=tcp_create_socket
-      --rename wasi:sockets/tcp@0.2.0=tcp
-      --rename wasi:sockets/udp-create-socket@0.2.0=udp_create_socket
-      --rename wasi:sockets/udp@0.2.0=udp
-      --rename wasi:cli/environment@0.2.0=environment
-      --rename wasi:cli/exit@0.2.0=exit
-      --rename wasi:cli/stdin@0.2.0=stdin
-      --rename wasi:cli/stdout@0.2.0=stdout
-      --rename wasi:cli/stderr@0.2.0=stderr
-      --rename wasi:cli/terminal-input@0.2.0=terminal_input
-      --rename wasi:cli/terminal-output@0.2.0=terminal_output
-      --rename wasi:cli/terminal-stdin@0.2.0=terminal_stdin
-      --rename wasi:cli/terminal-stdout@0.2.0=terminal_stdout
-      --rename wasi:cli/terminal-stderr@0.2.0=terminal_stderr
-      ${wit_dir}
-  COMMAND cmake -E copy wasip2.h ${bottom_half}/headers/public/wasi/
+      --world wasi:cli/imports@${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
+      ${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
-  COMMAND sed -i "'s_#include .wasip2\.h._#include \"wasi/wasip2.h\"_'" ${bottom_half}/sources/wasip2.c
-  COMMAND sed -i "s/extern void exit_exit/_Noreturn extern void exit_exit/" ${bottom_half}/headers/public/wasi/wasip2.h
-  COMMAND sed -i "s/extern void __wasm_import_exit_exit/_Noreturn extern void __wasm_import_exit_exit/" ${bottom_half}/sources/wasip2.c
-  DEPENDS wit-bindgen wasi-wits
+  DEPENDS wit-bindgen wasip2-wits
 )
+
+set(p3 0.3.0-rc-2025-09-16)
+ExternalProject_Add(
+  wasip3-wits
+  URL https://github.com/WebAssembly/wasi-cli/archive/refs/tags/v${p3}.tar.gz
+  CONFIGURE_COMMAND ""
+  BUILD_COMMAND ""
+  INSTALL_COMMAND ""
+  EXCLUDE_FROM_ALL TRUE
+)
+ExternalProject_Get_Property(wasip3-wits SOURCE_DIR)
+set(wasip3_wit_dir ${SOURCE_DIR}/wit-0.3.0-draft)
+
+add_custom_target(
+  bindings-p3
+  COMMAND
+    ${wit_bindgen} c
+      --autodrop-borrows yes
+      --rename-world wasip3
+      --type-section-suffix __wasi_libc
+      --world wasi:cli/imports@${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
+      ${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
+  COMMAND cmake -E copy wasip3.c ${bottom_half}/sources
+  DEPENDS wit-bindgen wasip3-wits
+)
+
+add_custom_target(bindings DEPENDS bindings-p2 bindings-p3)
+
+function(wit_bindgen_edit p)
+  add_custom_target(
+    bindings-${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
+    DEPENDS bindings-${p}
+  )
+  add_dependencies(bindings bindings-${p}-edit)
+endfunction()
+
+wit_bindgen_edit(p2)
+wit_bindgen_edit(p3)
diff --git a/cmake/check-symbols.cmake b/cmake/check-symbols.cmake
@@ -28,6 +28,8 @@ elseif(WASI STREQUAL "p1")
   set(expected "${CMAKE_SOURCE_DIR}/expected/wasm32-wasip1")
 elseif(WASI STREQUAL "p2")
   set(expected "${CMAKE_SOURCE_DIR}/expected/wasm32-wasip2")
+elseif(WASI STREQUAL "p3")
+  set(expected "${CMAKE_SOURCE_DIR}/expected/wasm32-wasip3")
 else()
   message(FATAL_ERROR "Unknown WASI version: ${WASI}")
 endif()

diff --git a/cmake/wasm-component-ld.cmake b/cmake/wasm-component-ld.cmake
@@ -9,6 +9,7 @@ if (NOT WASM_COMPONENT_LD_EXECUTABLE)
   )
   ExternalProject_Get_Property(wasm-component-ld SOURCE_DIR)
   set(WASM_COMPONENT_LD_EXECUTABLE "${SOURCE_DIR}/wasm-component-ld")
-  add_link_options(-fuse-ld=${WASM_COMPONENT_LD_EXECUTABLE})
-  add_dependencies(sysroot_inc wasm-component-ld)
+add_dependencies(sysroot_inc wasm-component-ld)
 endif()
+
+add_link_options(-fuse-ld=${WASM_COMPONENT_LD_EXECUTABLE})
diff --git a/expected/wasm32-wasip1-threads/defined-symbols.txt b/expected/wasm32-wasip1-threads/defined-symbols.txt
@@ -1390,4 +1390,4 @@ y0f
 y1
 y1f
 yn
-ynf
+ynf
diff --git a/expected/wasm32-wasip1-threads/include-all.c b/expected/wasm32-wasip1-threads/include-all.c
@@ -60,7 +60,6 @@
 #include <__typedef_suseconds_t.h>
 #include <__typedef_time_t.h>
 #include <__typedef_uid_t.h>
-#include <__wasi_snapshot.h>
 #include <alloca.h>
 #include <ar.h>
 #include <arpa/ftp.h>
@@ -172,5 +171,9 @@
 #include <wasi/libc-find-relpath.h>
 #include <wasi/libc-nocwd.h>
 #include <wasi/libc.h>
+#include <wasi/version.h>
+#include <wasi/wasip1.h>
+#include <wasi/wasip2.h>
+#include <wasi/wasip3.h>
 #include <wchar.h>
 #include <wctype.h>
-Original file line number
+Diff line change
@@ Expand Up / @@ -1390,4 +1390,4 @@ y0f @@
     y1
     y1f
     yn
-    ynf
+    ynf