Implement reference counting of I/O descriptions

.github/workflows/main.yml

@@ -39,7 +39,7 @@ jobs:
             upload: windows-clang-20
           - name: Build on WASIp2 Windows x86_64
             os: windows-2025
-            clang_version: 20.1.8
+            clang_version: 22.1.8
             args: -DTARGET_TRIPLE=wasm32-wasip2
 
           # Other versions of LLVM
@@ -74,7 +74,7 @@ jobs:
 
           - name: Test wasm32-wasip2
             os: ubuntu-24.04
-            clang_version: 20
+            clang_version: 22
             test: true
             upload: wasm32-wasip2
             args: -DTARGET_TRIPLE=wasm32-wasip2
@@ -113,7 +113,7 @@ jobs:
 
           - name: Test wasm32-wasip2 (debug)
             os: ubuntu-24.04
-            clang_version: 20
+            clang_version: 22
             test: true
             args: -DCMAKE_BUILD_TYPE=Debug -DTARGET_TRIPLE=wasm32-wasip2
 
@@ -125,14 +125,14 @@ jobs:
 
           - name: Test wasm32-wasip3
             os: ubuntu-24.04
-            clang_version: 20
+            clang_version: 22
             test: true
             upload: wasm32-wasip3
             args: -DTARGET_TRIPLE=wasm32-wasip3
 
           - name: Test wasm32-wasip3 (debug)
             os: ubuntu-24.04
-            clang_version: 20
+            clang_version: 22
             test: true
             args: -DCMAKE_BUILD_TYPE=Debug -DTARGET_TRIPLE=wasm32-wasip3
 
@@ -156,19 +156,19 @@ jobs:
 
           - name: Test LTO
             os: ubuntu-24.04
-            clang_version: 20
+            clang_version: 22
             test: true
             args: -DLTO=full -DTARGET_TRIPLE=wasm32-wasip2 -DCHECK_SYMBOLS=OFF
 
           - name: Test wasip2 on macOS
             os: macos-15
-            clang_version: wasi-sdk-30
+            clang_version: wasi-sdk-33
             test: true
             args: -DTARGET_TRIPLE=wasm32-wasip2 -DCMAKE_C_COMPILER_WORKS=ON
 
           - name: Test wasip2 on Windows
             os: windows-2025
-            clang_version: 20.1.8
+            clang_version: 22.1.8
             test: true
             args: -DTARGET_TRIPLE=wasm32-wasip2
 
@@ -248,11 +248,16 @@ jobs:
     - uses: actions/checkout@v6
       with:
         submodules: true
-    - run: cmake -S . -B build -DBUILD_TESTS=ON -G Ninja -DCMAKE_C_COMPILER=clang
+    - uses: ./.github/actions/setup
+      with:
+        clang_version: 22
+    - run: cmake -S . -B build -DBUILD_TESTS=ON -G Ninja -DCMAKE_C_COMPILER=clang-22
+    - run: ninja -C build format-check
+    - run: cmake -S . -B build -DTARGET_TRIPLE=wasm32-wasip1-threads
     - run: ninja -C build format-check
     - run: cmake -S . -B build -DTARGET_TRIPLE=wasm32-wasip2
     - run: ninja -C build format-check
-    - run: cmake -S . -B build -DTARGET_TRIPLE=wasm32-wasip1-threads
+    - run: cmake -S . -B build -DTARGET_TRIPLE=wasm32-wasip3
     - run: ninja -C build format-check
 
   rustfmt:

CMakeLists.txt

@@ -240,6 +240,15 @@ if(ENABLE_COOP_THREADS)
 else()
 endif()
 
+# In wasip2/wasip3 code we're using `defer { ... }`, so make sure that exists.
+include(CheckCCompilerFlag)
+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`")
+endif()
+
 # =============================================================================
 # Helper functions for adding libraries.
 

cmake/scripts/run-check-symbols.cmake

@@ -45,6 +45,10 @@ endforeach()
 list(FILTER defined_symbols INCLUDE REGEX " [A-Z] ")
 foreach(line IN LISTS defined_symbols)
   string(REGEX REPLACE ".* [A-Z] " "" symbol "${line}")
+  # Skip internal debug-only asserts
+  if (symbol MATCHES "__wasilibc_assert_.*")
+    continue()
+  endif()
   list(APPEND final_defined_symbols ${symbol})
 endforeach()
 list(SORT final_defined_symbols)
@@ -55,6 +59,10 @@ list(REMOVE_DUPLICATES final_defined_symbols)
 list(FILTER undefined_symbols INCLUDE REGEX " U ")
 foreach(line IN LISTS undefined_symbols)
   string(REGEX REPLACE ".* U " "" symbol "${line}")
+  # Skip internal debug-only asserts
+  if (symbol MATCHES "__wasilibc_assert_.*")
+    continue()
+  endif()
   list(APPEND final_undefined_symbols ${symbol})
 endforeach()
 list(SORT final_undefined_symbols)

expected/wasm32-wasip2/defined-symbols.txt

@@ -295,6 +295,7 @@ __wasilibc_add_tcp_socket
 __wasilibc_add_udp_socket
 __wasilibc_cwd
 __wasilibc_deinitialize_environ
+__wasilibc_descriptor_deallocate
 __wasilibc_dttoif
 __wasilibc_ensure_environ
 __wasilibc_environ
@@ -522,7 +523,7 @@ ctanl
 ctime
 ctime_r
 descriptor_table_clear
-descriptor_table_get_ref
+descriptor_table_get
 descriptor_table_insert
 descriptor_table_remove
 descriptor_table_renumber

expected/wasm32-wasip2/predefined-macros.txt

@@ -2978,6 +2978,7 @@
 #define __SIZE_TYPE__ long unsigned int
 #define __SIZE_WIDTH__ 32
 #define __STDARG_H 
+#define __STDC_DEFER_TS25755__ 1
 #define __STDC_HOSTED__ 1
 #define __STDC_IEC_559__ 1
 #define __STDC_ISO_10646__ 201206L

expected/wasm32-wasip3-coop/defined-symbols.txt

@@ -307,6 +307,7 @@ __wasilibc_add_tcp_socket
 __wasilibc_add_udp_socket
 __wasilibc_cwd
 __wasilibc_deinitialize_environ
+__wasilibc_descriptor_deallocate
 __wasilibc_dttoif
 __wasilibc_ensure_environ
 __wasilibc_environ
@@ -552,7 +553,7 @@ ctanl
 ctime
 ctime_r
 descriptor_table_clear
-descriptor_table_get_ref
+descriptor_table_get
 descriptor_table_insert
 descriptor_table_remove
 descriptor_table_renumber

expected/wasm32-wasip3-coop/predefined-macros.txt

@@ -2989,6 +2989,7 @@
 #define __SIZE_TYPE__ long unsigned int
 #define __SIZE_WIDTH__ 32
 #define __STDARG_H 
+#define __STDC_DEFER_TS25755__ 1
 #define __STDC_HOSTED__ 1
 #define __STDC_IEC_559__ 1
 #define __STDC_ISO_10646__ 201206L

expected/wasm32-wasip3/defined-symbols.txt

@@ -294,6 +294,7 @@ __wasilibc_add_tcp_socket
 __wasilibc_add_udp_socket
 __wasilibc_cwd
 __wasilibc_deinitialize_environ
+__wasilibc_descriptor_deallocate
 __wasilibc_dttoif
 __wasilibc_ensure_environ
 __wasilibc_environ
@@ -529,7 +530,7 @@ ctanl
 ctime
 ctime_r
 descriptor_table_clear
-descriptor_table_get_ref
+descriptor_table_get
 descriptor_table_insert
 descriptor_table_remove
 descriptor_table_renumber

expected/wasm32-wasip3/predefined-macros.txt

@@ -2984,6 +2984,7 @@
 #define __SIZE_TYPE__ long unsigned int
 #define __SIZE_WIDTH__ 32
 #define __STDARG_H 
+#define __STDC_DEFER_TS25755__ 1
 #define __STDC_HOSTED__ 1
 #define __STDC_IEC_559__ 1
 #define __STDC_ISO_10646__ 201206L

libc-bottom-half/CMakeLists.txt

@@ -219,6 +219,7 @@ foreach(file crt/crt1-command.c
   target_link_libraries(${stem} PRIVATE musl-top-half-interface)
   set_pic(${stem})
   target_compile_options(${stem} PRIVATE -fvisibility=default -fno-lto)
+  target_include_directories(${stem} PRIVATE headers/private)
 endforeach()
 
 set(crt_sysroot ${SYSROOT}/lib/${TARGET_TRIPLE})

libc-bottom-half/cloudlibc/src/libc/dirent/fdopendir.c

@@ -8,6 +8,7 @@
 #include <wasi/api.h>
 
 #ifndef __wasip1__
+#include <stddefer.h>
 #include <wasi/file_utils.h>
 #include <common/errors.h>
 #else
@@ -50,12 +51,14 @@ DIR *fdopendir(int fd) {
   dirp->dirent_size = 1;
   return dirp;
 #elif defined(__wasip2__) || defined(__wasip3__)
+  defer free(dirp);
+
   // Translate the file descriptor to an internal handle
   filesystem_borrow_descriptor_t file_handle;
-  if (fd_to_file_handle(fd, &file_handle) < 0) {
-    free(dirp);
+  descriptor_table_entry_t entry;
+  if (fd_to_file_handle(fd, &entry, &file_handle) < 0)
     return NULL;
-  }
+  defer descriptor_table_entry_dec(entry);
 
   // Read the directory
 #if defined(__wasip2__)
@@ -65,7 +68,6 @@ DIR *fdopendir(int fd) {
                                                         &result,
                                                         &error_code);
   if (!ok) {
-    free(dirp);
     translate_error(&error_code);
     return NULL;
   }
@@ -80,7 +82,9 @@ DIR *fdopendir(int fd) {
   dirp->offset = 0;
   dirp->dirent = NULL;
   dirp->dirent_size = 1;
-  return dirp;
+  DIR *ret = dirp;
+  dirp = NULL;
+  return ret;
 #else
 # error "Unsupported WASI version"
 #endif

libc-bottom-half/cloudlibc/src/libc/dirent/readdir.c

@@ -15,6 +15,7 @@
 #include <string.h>
 
 #ifndef __wasip1__
+#include <stddefer.h>
 #include <wasi/file_utils.h>
 #include <common/errors.h>
 #endif
@@ -147,9 +148,19 @@ struct dirent *readdir(DIR *dirp) {
 }
 
 #elif defined(__wasip2__) || defined(__wasip3__)
-
-static int ensure_has_directory_stream(DIR *dirp, filesystem_borrow_descriptor_t *handle) {
-  if (fd_to_file_handle(dirp->fd, handle) < 0)
+// Ensures that `dirp` has the necessary streams prepared to start reading
+// directory entries.
+//
+// On success returns `entry`, the owned entry for this operation that must be
+// deallocated with `descriptor_table_entry_dec` when done, and `handle`, the
+// WASI file that's being used. Additionally `dirp`'s streams are filled and
+// ready for use.
+//
+// On failure returns -1 and `entry` need not be deallocated.
+static int ensure_has_directory_stream(DIR *dirp,
+                                       descriptor_table_entry_t *entry,
+                                       filesystem_borrow_descriptor_t *handle) {
+  if (fd_to_file_handle(dirp->fd, entry, handle) < 0)
     return -1;
 
 #ifdef __wasip2__
@@ -162,6 +173,7 @@ static int ensure_has_directory_stream(DIR *dirp, filesystem_borrow_descriptor_t
                                                         &error_code);
   if (!ok) {
     translate_error(&error_code);
+    descriptor_table_entry_dec(*entry);
     return -1;
   }
 #elif defined(__wasip3__)
@@ -176,9 +188,11 @@ static struct dirent *readdir_next(DIR *dirp) {
   filesystem_metadata_hash_value_t metadata;
   filesystem_error_code_t error_code;
   filesystem_borrow_descriptor_t dir_handle;
+  descriptor_table_entry_t entry;
 
-  if (ensure_has_directory_stream(dirp, &dir_handle) < 0)
+  if (ensure_has_directory_stream(dirp, &entry, &dir_handle) < 0)
     return NULL;
+  defer descriptor_table_entry_dec(entry);
 
   // Yield '.' first if the offset is 0. Note that `d_ino` is from the metadata
   // hash of the directory itself.

libc-bottom-half/cloudlibc/src/libc/fcntl/fcntl.c

@@ -8,15 +8,17 @@
 #include <stdarg.h>
 
 #ifndef __wasip1__
+#include <stddefer.h>
 #include <wasi/file_utils.h>
 #include <common/errors.h>
 #endif
 
 int fcntl(int fildes, int cmd, ...) {
 #if defined(__wasip2__) || defined(__wasip3__)
-  descriptor_table_entry_t *entry = descriptor_table_get_ref(fildes);
-  if (entry == NULL)
+  descriptor_table_entry_t entry;
+  if (descriptor_table_get(fildes, &entry) < 0)
     return -1;
+  defer descriptor_table_entry_dec(entry);
 #endif
 
   switch (cmd) {
@@ -52,11 +54,11 @@ int fcntl(int fildes, int cmd, ...) {
       }
       return oflags;
 #elif defined(__wasip2__) || defined(__wasip3__) 
-      if (!entry->vtable->fcntl_getfl) {
+      if (!entry.vtable->fcntl_getfl) {
         errno = EINVAL;
         return -1;
       }
-      return entry->vtable->fcntl_getfl(entry->data);
+      return entry.vtable->fcntl_getfl(entry.data);
 #else
 # error "Unknown WASI version"
 #endif
@@ -77,11 +79,11 @@ int fcntl(int fildes, int cmd, ...) {
         return -1;
       }
 #elif defined(__wasip2__) || defined(__wasip3__)
-      if (!entry->vtable->fcntl_setfl) {
+      if (!entry.vtable->fcntl_setfl) {
         errno = EINVAL;
         return -1;
       }
-      return entry->vtable->fcntl_setfl(entry->data, flags);
+      return entry.vtable->fcntl_setfl(entry.data, flags);
 #else
 # error "Unknown WASI version"
 #endif

libc-bottom-half/cloudlibc/src/libc/fcntl/openat.c

@@ -10,6 +10,7 @@
 #include <string.h>
 
 #ifndef __wasip1__
+#include <stddefer.h>
 #include <wasi/file.h>
 #include <wasi/descriptor_table.h>
 #include <wasi/file_utils.h>
@@ -136,8 +137,10 @@ int __wasilibc_nocwd_openat_nomode(int fd, const char *path, int oflag) {
 
   // Translate the file descriptor to an internal handle
   filesystem_borrow_descriptor_t file_handle;
-  if (fd_to_file_handle(fd, &file_handle) < 0)
+  descriptor_table_entry_t entry;
+  if (fd_to_file_handle(fd, &entry, &file_handle) < 0)
     return -1;
+  defer descriptor_table_entry_dec(entry);
 
   // Construct a WASI string for the path
   wasi_string_t wasi_path;

libc-bottom-half/cloudlibc/src/libc/fcntl/posix_fadvise.c

@@ -8,6 +8,7 @@
 #include <wasi/api.h>
 
 #ifndef __wasip1__
+#include <stddefer.h>
 #include <wasi/file_utils.h>
 #include <common/errors.h>
 #endif
@@ -32,8 +33,10 @@ int posix_fadvise(int fd, off_t offset, off_t len, int advice) {
   return __wasi_fd_advise(fd, offset, len, advice);
 #elif defined(__wasip2__) || defined(__wasip3__)
   filesystem_borrow_descriptor_t file_handle;
-  if (fd_to_file_handle(fd, &file_handle) < 0)
+  descriptor_table_entry_t entry;
+  if (fd_to_file_handle(fd, &entry, &file_handle) < 0)
     return EBADF;
+  defer descriptor_table_entry_dec(entry);
   if (file_handle.__handle == 0) {
     errno = EBADF;
     return EBADF;