bvisness · Sep 30, 2026 · Sep 30, 2026 · Sep 30, 2026 · Oct 3, 2026 · Oct 3, 2026
diff --git a/.gitattributes b/.gitattributes
@@ -10,5 +10,7 @@ expected linguist-generated
 # Flag some wit-bindgen-generated files checked into the repo as generated
 __generated_wasip2.h linguist-generated
 __generated_wasip3.h linguist-generated
+__generated_webp2.h linguist-generated
 libc-bottom-half/sources/wasip2.c linguist-generated
 libc-bottom-half/sources/wasip3.c linguist-generated
+libc-bottom-half/sources/webp2.c linguist-generated
diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
@@ -148,6 +148,14 @@ jobs:
             test: true
             args: -DCMAKE_BUILD_TYPE=Debug -DTARGET_TRIPLE=wasm32-wasip3 -DENABLE_COOP_THREADS=ON
 
+          - name: Test wasm32-webp2
+            os: ubuntu-24.04
+            clang_version: 22
+            upload: wasm32-webp2
+            # TODO(webp2): Enable tests once there is a way to run them.
+            test: false
+            args: -DTARGET_TRIPLE=wasm32-webp2
+
           - name: Test emmalloc
             os: ubuntu-24.04
             clang_version: 20
@@ -259,6 +267,8 @@ jobs:
     - run: ninja -C build format-check
     - run: cmake -S . -B build -DTARGET_TRIPLE=wasm32-wasip3
     - run: ninja -C build format-check
+    - run: cmake -S . -B build -DTARGET_TRIPLE=wasm32-webp2
+    - run: ninja -C build format-check
 
   rustfmt:
     name: Rustfmt
@@ -279,6 +289,9 @@ jobs:
     - uses: actions/checkout@v6
       with:
         submodules: true
+    # TODO(webp2): Switch back to a released wit-bindgen once one ships with
+    # getter/setter support (bytecodealliance/wit-bindgen#1726).
+    - run: cargo install wit-bindgen-cli --locked --git https://github.com/bytecodealliance/wit-bindgen --rev 7fb7a6a072a2c7d225fa183b93acfabdc36e744b
     - run: CC=clang cmake -S . -B build -G Ninja
     - run: ninja -C build bindings
     - run: git diff --exit-code

diff --git a/CMakeLists.txt b/CMakeLists.txt
@@ -12,8 +12,17 @@ if(NOT CMAKE_BUILD_TYPE)
   set(CMAKE_BUILD_TYPE "Release" CACHE STRING "Build type to use" FORCE)
 endif()
 
-# Force a cross-compile to WASI at all times.
-set(CMAKE_SYSTEM_NAME WASI)
+set(TARGET_TRIPLE "wasm32-wasip1" CACHE STRING "WASI target to test")
+set(CMAKE_C_COMPILER_TARGET ${TARGET_TRIPLE})
+
+# Force a cross-compile to WASI or WEB at all times.
+if(TARGET_TRIPLE MATCHES "-wasi")
+  set(CMAKE_SYSTEM_NAME WASI)
+elseif(TARGET_TRIPLE MATCHES "-web")
+  set(CMAKE_SYSTEM_NAME WEB)
+else()
+  message(FATAL_ERROR "Unknown target triple: ${TARGET_TRIPLE}")
+endif()
 
 # I'm not entirely sure why this is necessary on Windows. This may be a bug in
 # CMake, I'm not sure. The problem is that, at least on CI, CMake detects that
@@ -26,9 +35,6 @@ if (CMAKE_HOST_WIN32)
   set(CMAKE_INCLUDE_SYSTEM_FLAG_C "-isystem ")
 endif()
 
-set(TARGET_TRIPLE "wasm32-wasip1" CACHE STRING "WASI target to test")
-set(CMAKE_C_COMPILER_TARGET ${TARGET_TRIPLE})
-
 # We're building libc, and the compiler being used may not have a wasm sysroot
 # for libc, so skip this check. Otherwise the `project` call below attempts a
 # link to see if the compiler is working and if that fails it doesn't mean it
@@ -79,8 +85,11 @@ elseif(TARGET_TRIPLE MATCHES "-wasip2$")
 elseif(TARGET_TRIPLE MATCHES "-wasip3$")
   set(WASI p3)
   set(SHARED ON)
+elseif(TARGET_TRIPLE MATCHES "-webp2$")
+  set(WEB p2)
+  set(SHARED ON)
 else()
-  message(FATAL_ERROR "Unknown WASI target triple: ${TARGET_TRIPLE}")
+  message(FATAL_ERROR "Unknown target triple: ${TARGET_TRIPLE}")
 endif()
 
 if(BUILD_SHARED)
@@ -149,12 +158,15 @@ elseif(WASI STREQUAL "p2")
   set(__wasip2__ ON)
 elseif(WASI STREQUAL "p3")
   set(__wasip3__ ON)
+elseif(WEB STREQUAL "p2")
+  set(__webp2__ ON)
 else()
   message(FATAL_ERROR "Unknown WASI version: ${WASI}")
 endif()
 
 set(wasip2-version 0.2.12)
 set(wasip3-version 0.3.0)
+set(webp2-version 0.2.0)
 
 # =============================================================================
 # Detection of a libcall thread context for wasip3
@@ -204,6 +216,12 @@ add_link_options(
   -resource-dir ${tmp_resource_dir}
 )
 
+if(__webp2__)
+  # TODO(webp2): Manually instruct clang to look at our new webp2 sysroot until
+  # it has been patched in wasi-sdk to know about "webp2" as an OS.
+  add_link_options(-B${SYSROOT_LIB} -L${SYSROOT_LIB})
+endif()
+
 # Expose the public headers to the implementation. We use `-isystem` for
 # purpose for two reasons:
 #
@@ -251,7 +269,7 @@ check_c_compiler_flag(-fdefer-ts HAVE_FDEFER_TS)
 if(HAVE_FDEFER_TS)
   add_compile_options(-fdefer-ts)
 elseif(NOT WASI STREQUAL "p1")
-  message(FATAL_ERROR "wasip2/wasip3 require clang 22 or later for `-fdefer-ts`")
+  message(FATAL_ERROR "wasip2/wasip3/webp2 require clang 22 or later for `-fdefer-ts`")
 endif()
 
 # =============================================================================
@@ -372,6 +390,8 @@ 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)
+elseif (WEB STREQUAL "p2")
+  set(libc_extra_objects libc-bottom-half/sources/webp2_component_type.o)
 endif()
 
 add_library(c SHARED EXCLUDE_FROM_ALL

diff --git a/cmake/Platform/WEB.cmake b/cmake/Platform/WEB.cmake
@@ -0,0 +1 @@
+set(WEB 1)
diff --git a/cmake/bindings.cmake b/cmake/bindings.cmake
@@ -15,8 +15,8 @@ if(WIT_BINDGEN_EXECUTABLE)
     OUTPUT_VARIABLE WIT_BINDGEN_VERSION
     OUTPUT_STRIP_TRAILING_WHITESPACE)
 
-  if (NOT (WIT_BINDGEN_VERSION MATCHES "0\\.60\\.0"))
-    message(WARNING "wit-bindgen version 0.60.0 is required, found: ${WIT_BINDGEN_VERSION}")
+  if (NOT (WIT_BINDGEN_VERSION MATCHES "0\\.62\\.0"))
+    message(WARNING "wit-bindgen version 0.62.0 is required, found: ${WIT_BINDGEN_VERSION}")
     set(WIT_BINDGEN_EXECUTABLE "")
   endif()
 endif()
@@ -26,7 +26,7 @@ if (NOT WIT_BINDGEN_EXECUTABLE)
   ba_download(
     wit-bindgen
     "https://github.com/bytecodealliance/wit-bindgen"
-    "0.60.0"
+    "0.62.0"
   )
   ExternalProject_Get_Property(wit-bindgen SOURCE_DIR)
   set(wit_bindgen "${SOURCE_DIR}/wit-bindgen")
@@ -38,7 +38,7 @@ endif()
 set(bottom_half "${CMAKE_SOURCE_DIR}/libc-bottom-half")
 
 add_custom_target(
-  bindings-p2
+  bindings-wasip2
   COMMAND
     ${wit_bindgen} c
       --autodrop-borrows yes
@@ -80,7 +80,7 @@ add_custom_target(
 )
 
 add_custom_target(
-  bindings-p3
+  bindings-wasip3
   COMMAND
     ${wit_bindgen} c
       --autodrop-borrows yes
@@ -138,7 +138,23 @@ add_custom_target(
   DEPENDS wit-bindgen wasip3-wits
 )
 
-add_custom_target(bindings DEPENDS bindings-p2 bindings-p3)
+add_custom_target(
+  bindings-webp2
+  COMMAND
+    ${wit_bindgen} c
+      --autodrop-borrows yes
+      --rename wasm:js/global=webp2
+      --rename wasm:js/console=webp2_console
+      --rename-world webp2
+      --type-section-suffix __wasi_libc
+      ${CMAKE_SOURCE_DIR}/web/p2/wit
+  COMMAND cmake -E copy webp2.h ${bottom_half}/headers/public/wasi/__generated_webp2.h
+  COMMAND cmake -E copy webp2_component_type.o ${bottom_half}/sources
+  COMMAND cmake -E copy webp2.c ${bottom_half}/sources
+  DEPENDS wit-bindgen
+)
+
+add_custom_target(bindings DEPENDS bindings-wasip2 bindings-wasip3 bindings-webp2)
 
 if(CMAKE_HOST_SYSTEM_NAME STREQUAL "Darwin")
   set(SED_INPLACE_ARGS -i '')
@@ -149,13 +165,14 @@ endif()
 function(wit_bindgen_edit p)
   add_custom_target(
     bindings-${p}-edit
-    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
+    COMMAND sed ${SED_INPLACE_ARGS} "'s_#include .${p}\.h._#include \"wasi/${p}.h\"_'" ${bottom_half}/sources/${p}.c
+    COMMAND sed ${SED_INPLACE_ARGS} "s/extern void exit_exit/_Noreturn extern void exit_exit/" ${bottom_half}/headers/public/wasi/__generated_${p}.h
+    COMMAND sed ${SED_INPLACE_ARGS} "s/extern void __wasm_import_exit_exit/_Noreturn extern void __wasm_import_exit_exit/" ${bottom_half}/sources/${p}.c
     DEPENDS bindings-${p}
   )
   add_dependencies(bindings bindings-${p}-edit)
 endfunction()
 
-wit_bindgen_edit(p2)
-wit_bindgen_edit(p3)
+wit_bindgen_edit(wasip2)
+wit_bindgen_edit(wasip3)
+wit_bindgen_edit(webp2)
diff --git a/cmake/check-symbols.cmake b/cmake/check-symbols.cmake
@@ -36,6 +36,8 @@ elseif(WASI STREQUAL "p3")
   else()
     set(expected "${CMAKE_SOURCE_DIR}/expected/wasm32-wasip3")
   endif()
+elseif(WEB STREQUAL "p2")
+  set(expected "${CMAKE_SOURCE_DIR}/expected/wasm32-webp2")
 else()
   message(FATAL_ERROR "Unknown WASI version: ${WASI}")
 endif()

diff --git a/cmake/clang-format.cmake b/cmake/clang-format.cmake
@@ -21,7 +21,7 @@ set(formatted_sources)
 
 function(clang_format_file file)
   if (file MATCHES "__generated" OR
-      file MATCHES "wasip.\.c$" OR # Skip auto-generated files
+      file MATCHES "(wasip.|webp2)\.c$" OR # Skip auto-generated files
       file MATCHES "\.(s|S)$")     # Skip assembly files
     return()
   endif()

diff --git a/cmake/wasm-component-ld.cmake b/cmake/wasm-component-ld.cmake
@@ -3,7 +3,7 @@ if (NOT USE_WASM_COMPONENT_LD)
   return()
 endif()
 
-set(WASM_COMPONENT_LD_REQUIRED_VERSION "0.5.30")
+set(WASM_COMPONENT_LD_REQUIRED_VERSION "0.5.31")
 
 find_program(WASM_COMPONENT_LD_EXECUTABLE NAMES wasm-component-ld)
 

diff --git a/cmake/wasm-tools.cmake b/cmake/wasm-tools.cmake
@@ -5,7 +5,7 @@ if (NOT WASM_TOOLS_EXECUTABLE)
   ba_download(
     wasm-tools
     "https://github.com/bytecodealliance/wasm-tools"
-    "1.257.0"
+    "1.261.0"
   )
   ExternalProject_Get_Property(wasm-tools SOURCE_DIR)
   set(wasm_tools "${SOURCE_DIR}/wasm-tools")

diff --git a/expected/wasm32-wasip1-threads/defined-symbols.txt b/expected/wasm32-wasip1-threads/defined-symbols.txt
@@ -397,6 +397,8 @@ __wasilibc_pthread_self
 __wasilibc_register_preopened_fd
 __wasilibc_rename_newat
 __wasilibc_rename_oldat
+__wasilibc_report_error
+__wasilibc_report_errorf
 __wasilibc_reset_preopens
 __wasilibc_rmdirat
 __wasilibc_stat

diff --git a/expected/wasm32-wasip1-threads/include-all.c b/expected/wasm32-wasip1-threads/include-all.c
@@ -174,5 +174,6 @@
 #include <wasi/wasip1.h>
 #include <wasi/wasip2.h>
 #include <wasi/wasip3.h>
+#include <wasi/webp2.h>
 #include <wchar.h>
 #include <wctype.h>
diff --git a/expected/wasm32-wasip1-threads/predefined-macros.txt b/expected/wasm32-wasip1-threads/predefined-macros.txt
@@ -3061,7 +3061,8 @@
 #define __WASI_SUBCLOCKFLAGS_SUBSCRIPTION_CLOCK_ABSTIME ((__wasi_subclockflags_t)(1 << 0))
 #define __WASI_VERSION_H 
 #define __WASI_WASIP2_H 
-#define __WASI_WASIP3_H 
+#define __WASI_WASIP3_H
+#define __WASI_WEBP2_H
 #define __WASI_WHENCE_CUR (UINT8_C(1))
 #define __WASI_WHENCE_END (UINT8_C(2))
 #define __WASI_WHENCE_SET (UINT8_C(0))

diff --git a/expected/wasm32-wasip1/defined-symbols.txt b/expected/wasm32-wasip1/defined-symbols.txt
@@ -385,6 +385,8 @@ __wasilibc_pthread_self
 __wasilibc_register_preopened_fd
 __wasilibc_rename_newat
 __wasilibc_rename_oldat
+__wasilibc_report_error
+__wasilibc_report_errorf
 __wasilibc_reset_preopens
 __wasilibc_rmdirat
 __wasilibc_stat

diff --git a/expected/wasm32-wasip1/include-all.c b/expected/wasm32-wasip1/include-all.c
@@ -174,5 +174,6 @@
 #include <wasi/wasip1.h>
 #include <wasi/wasip2.h>
 #include <wasi/wasip3.h>
+#include <wasi/webp2.h>
 #include <wchar.h>
 #include <wctype.h>
diff --git a/expected/wasm32-wasip1/predefined-macros.txt b/expected/wasm32-wasip1/predefined-macros.txt
@@ -3060,7 +3060,8 @@
 #define __WASI_SUBCLOCKFLAGS_SUBSCRIPTION_CLOCK_ABSTIME ((__wasi_subclockflags_t)(1 << 0))
 #define __WASI_VERSION_H 
 #define __WASI_WASIP2_H 
-#define __WASI_WASIP3_H 
+#define __WASI_WASIP3_H
+#define __WASI_WEBP2_H
 #define __WASI_WHENCE_CUR (UINT8_C(1))
 #define __WASI_WHENCE_END (UINT8_C(2))
 #define __WASI_WHENCE_SET (UINT8_C(0))

diff --git a/expected/wasm32-wasip2/defined-symbols.txt b/expected/wasm32-wasip2/defined-symbols.txt
@@ -357,6 +357,8 @@ __wasilibc_random
 __wasilibc_read
 __wasilibc_rename_newat
 __wasilibc_rename_oldat
+__wasilibc_report_error
+__wasilibc_report_errorf
 __wasilibc_reset_preopens
 __wasilibc_rmdirat
 __wasilibc_setsockopt_timeout

diff --git a/expected/wasm32-wasip2/include-all.c b/expected/wasm32-wasip2/include-all.c
@@ -176,5 +176,6 @@
 #include <wasi/wasip1.h>
 #include <wasi/wasip2.h>
 #include <wasi/wasip3.h>
+#include <wasi/webp2.h>
 #include <wchar.h>
 #include <wctype.h>
diff --git a/expected/wasm32-wasip2/predefined-macros.txt b/expected/wasm32-wasip2/predefined-macros.txt
@@ -3061,7 +3061,8 @@
 #define __USE_TIME_BITS64 1
 #define __WASI_VERSION_H 
 #define __WASI_WASIP2_H 
-#define __WASI_WASIP3_H 
+#define __WASI_WASIP3_H
+#define __WASI_WEBP2_H
 #define __WCHAR_TYPE__ int
 #define __WCHAR_WIDTH__ 32
 #define __WINT_TYPE__ int

diff --git a/expected/wasm32-wasip3-coop/defined-symbols.txt b/expected/wasm32-wasip3-coop/defined-symbols.txt
@@ -385,6 +385,8 @@ __wasilibc_read
 __wasilibc_read_poll
 __wasilibc_rename_newat
 __wasilibc_rename_oldat
+__wasilibc_report_error
+__wasilibc_report_errorf
 __wasilibc_reset_preopens
 __wasilibc_rmdirat
 __wasilibc_setsockopt_timeout

diff --git a/expected/wasm32-wasip3-coop/include-all.c b/expected/wasm32-wasip3-coop/include-all.c
@@ -176,5 +176,6 @@
 #include <wasi/wasip1.h>
 #include <wasi/wasip2.h>
 #include <wasi/wasip3.h>
+#include <wasi/webp2.h>
 #include <wchar.h>
 #include <wctype.h>
diff --git a/expected/wasm32-wasip3-coop/predefined-macros.txt b/expected/wasm32-wasip3-coop/predefined-macros.txt
@@ -3068,7 +3068,8 @@
 #define __USE_TIME_BITS64 1
 #define __WASI_VERSION_H 
 #define __WASI_WASIP2_H 
-#define __WASI_WASIP3_H 
+#define __WASI_WASIP3_H
+#define __WASI_WEBP2_H
 #define __WCHAR_TYPE__ int
 #define __WCHAR_WIDTH__ 32
 #define __WINT_TYPE__ int

diff --git a/expected/wasm32-wasip3/defined-symbols.txt b/expected/wasm32-wasip3/defined-symbols.txt
@@ -359,6 +359,8 @@ __wasilibc_read
 __wasilibc_read_poll
 __wasilibc_rename_newat
 __wasilibc_rename_oldat
+__wasilibc_report_error
+__wasilibc_report_errorf
 __wasilibc_reset_preopens
 __wasilibc_rmdirat
 __wasilibc_setsockopt_timeout

diff --git a/expected/wasm32-wasip3/include-all.c b/expected/wasm32-wasip3/include-all.c
@@ -176,5 +176,6 @@
 #include <wasi/wasip1.h>
 #include <wasi/wasip2.h>
 #include <wasi/wasip3.h>
+#include <wasi/webp2.h>
 #include <wchar.h>
 #include <wctype.h>
diff --git a/expected/wasm32-wasip3/predefined-macros.txt b/expected/wasm32-wasip3/predefined-macros.txt
@@ -3067,7 +3067,8 @@
 #define __USE_TIME_BITS64 1
 #define __WASI_VERSION_H 
 #define __WASI_WASIP2_H 
-#define __WASI_WASIP3_H 
+#define __WASI_WASIP3_H
+#define __WASI_WEBP2_H
 #define __WCHAR_TYPE__ int
 #define __WCHAR_WIDTH__ 32
 #define __WINT_TYPE__ int