wasm2c: support the custom-page-sizes proposal (#2508)

keithw · web-flow · commit d75737b1c2a8 · 2025-03-01T09:35:22.000-08:00
diff --git a/README.md b/README.md
@@ -62,7 +62,7 @@ Wabt has been compiled to JavaScript via emscripten. Some of the functionality i
 | [multi-memory][]      | `--enable-multi-memory`     |   | ✓ | ✓ | ✓ | ✓ | ✓ |
 | [extended-const][]    | `--enable-extended-const`   |   | ✓ | ✓ | ✓ | ✓ | ✓ |
 | [relaxed-simd][]      | `--enable-relaxed-simd`     |   | ✓ | ✓ | ✓ | ✓ |   |
-| [custom-page-sizes][] | `--enable-custom-page-sizes`|   | ✓ | ✓ | ✓ | ✓ |   |
+| [custom-page-sizes][] | `--enable-custom-page-sizes`|   | ✓ | ✓ | ✓ | ✓ | ✓ |
 
 [exception handling]: https://github.com/WebAssembly/exception-handling
 [mutable globals]: https://github.com/WebAssembly/mutable-global
diff --git a/src/c-writer.cc b/src/c-writer.cc
@@ -2248,18 +2248,17 @@ void CWriter::WriteDataInitializers() {
     Index memory_idx = module_->num_memory_imports;
     for (Index i = memory_idx; i < module_->memories.size(); i++) {
       const Memory* memory = module_->memories[i];
-      uint64_t max;
-      if (memory->page_limits.has_max) {
-        max = memory->page_limits.max;
-      } else {
-        max = memory->page_limits.is_64 ? (static_cast<uint64_t>(1) << 48)
-                                        : 65536;
-      }
+      const uint64_t max =
+          memory->page_limits.has_max
+              ? memory->page_limits.max
+              : WABT_BYTES_TO_MIN_PAGES(
+                    (memory->page_limits.is_64 ? UINT64_MAX : UINT32_MAX),
+                    memory->page_size);
       std::string func = GetMemoryAPIString(*memory, "wasm_rt_allocate_memory");
-      Write(func, "(",
-            ExternalInstancePtr(ModuleFieldType::Memory, memory->name), ", ",
-            memory->page_limits.initial, ", ", max, ", ",
-            memory->page_limits.is_64, ");", Newline());
+      Write(
+          func, "(", ExternalInstancePtr(ModuleFieldType::Memory, memory->name),
+          ", ", memory->page_limits.initial, ", ", max, ", ",
+          memory->page_limits.is_64, ", ", memory->page_size, ");", Newline());
     }
   }
 
@@ -2898,6 +2897,8 @@ void CWriter::WriteImportProperties(CWriterPhase kind) {
       write_import_prop(import, "max", "u64",
                         limits->has_max ? limits->max : default_max);
       write_import_prop(import, "is64", "u8", limits->is_64);
+      write_import_prop(import, "pagesize", "u32",
+                        cast<MemoryImport>(import)->memory.page_size);
     } else if (import->kind() == ExternalKind::Table) {
       const Limits* limits = &(cast<TableImport>(import)->table.elem_limits);
       const uint64_t default_max = std::numeric_limits<uint32_t>::max();
diff --git a/src/tools/wasm2c.cc b/src/tools/wasm2c.cc
@@ -58,9 +58,12 @@ static const char s_description[] =
 )";
 
 static const std::string supported_features[] = {
-    "multi-memory", "multi-value", "sign-extension", "saturating-float-to-int",
-    "exceptions",   "memory64",    "extended-const", "simd",
-    "threads",      "tail-call"};
+    "multi-memory",     "multi-value",
+    "sign-extension",   "saturating-float-to-int",
+    "exceptions",       "memory64",
+    "extended-const",   "simd",
+    "threads",          "tail-call",
+    "custom-page-sizes"};
 
 static bool IsFeatureSupported(const std::string& feature) {
   return std::find(std::begin(supported_features), std::end(supported_features),
diff --git a/test/run-spec-wasm2c.py b/test/run-spec-wasm2c.py
@@ -551,6 +551,7 @@ def main(args):
     parser.add_argument('--enable-extended-const', action='store_true')
     parser.add_argument('--enable-threads', action='store_true')
     parser.add_argument('--enable-tail-call', action='store_true')
+    parser.add_argument('--enable-custom-page-sizes', action='store_true')
     parser.add_argument('--disable-bulk-memory', action='store_true')
     parser.add_argument('--disable-reference-types', action='store_true')
     parser.add_argument('--debug-names', action='store_true')
@@ -572,6 +573,7 @@ def main(args):
             '--enable-extended-const': options.enable_extended_const,
             '--enable-threads': options.enable_threads,
             '--enable-tail-call': options.enable_tail_call,
+            '--enable-custom-page-sizes': options.enable_custom_page_sizes,
             '--enable-multi-memory': options.enable_multi_memory,
             '--disable-bulk-memory': options.disable_bulk_memory,
             '--disable-reference-types': options.disable_reference_types,
@@ -591,6 +593,7 @@ def main(args):
             '--enable-extended-const': options.enable_extended_const,
             '--enable-threads': options.enable_threads,
             '--enable-tail-call': options.enable_tail_call,
+            '--enable-custom-page-sizes': options.enable_custom_page_sizes,
             '--enable-multi-memory': options.enable_multi_memory})
 
         options.cflags += shlex.split(os.environ.get('WASM2C_CFLAGS', ''))
diff --git a/test/spec-wasm2c-prefix.c b/test/spec-wasm2c-prefix.c
@@ -427,7 +427,8 @@ static void init_spectest_module(w2c_spectest* instance) {
   instance->spectest_global_i64 = 666l;
   instance->spectest_global_f32 = 666.6;
   instance->spectest_global_f64 = 666.6;
-  wasm_rt_allocate_memory(&instance->spectest_memory, 1, 2, false);
+  wasm_rt_allocate_memory(&instance->spectest_memory, 1, 2, false,
+                          WASM_DEFAULT_PAGE_SIZE);
   wasm_rt_allocate_funcref_table(&instance->spectest_table, 10, 20);
   wasm_rt_allocate_funcref_table(&instance->spectest_table64, 10, 20);
 }
diff --git a/test/wasm2c/check-imports.txt b/test/wasm2c/check-imports.txt
@@ -63,6 +63,7 @@ extern const u32 wasm2c_test_max_env_0x5F_indirect_function_table;
 extern const u64 wasm2c_test_min_env_0x5F_linear_memory;
 extern const u64 wasm2c_test_max_env_0x5F_linear_memory;
 extern const u8 wasm2c_test_is64_env_0x5F_linear_memory;
+extern const u32 wasm2c_test_pagesize_env_0x5F_linear_memory;
 
 #ifdef __cplusplus
 }
@@ -857,6 +858,7 @@ const u32 wasm2c_test_max_env_0x5F_indirect_function_table = 4294967295;
 const u64 wasm2c_test_min_env_0x5F_linear_memory = 0;
 const u64 wasm2c_test_max_env_0x5F_linear_memory = 65536;
 const u8 wasm2c_test_is64_env_0x5F_linear_memory = 0;
+const u32 wasm2c_test_pagesize_env_0x5F_linear_memory = 65536;
 
 void wasm2c_test_instantiate(w2c_test* instance, struct w2c_env* w2c_env_instance) {
   assert(wasm_rt_is_initialized());
diff --git a/test/wasm2c/export-names.txt b/test/wasm2c/export-names.txt
@@ -48,6 +48,7 @@ wasm_rt_func_type_t wasm2c_test_get_func_type(uint32_t param_count, uint32_t res
 extern const u64 wasm2c_test_min_0x5Cmodule_import0x200x2A0x2F;
 extern const u64 wasm2c_test_max_0x5Cmodule_import0x200x2A0x2F;
 extern const u8 wasm2c_test_is64_0x5Cmodule_import0x200x2A0x2F;
+extern const u32 wasm2c_test_pagesize_0x5Cmodule_import0x200x2A0x2F;
 
 /* export: '' */
 void w2c_test_(w2c_test*);
@@ -905,6 +906,7 @@ static void init_instance_import(w2c_test* instance, struct w2c_0x5Cmodule* w2c_
 const u64 wasm2c_test_min_0x5Cmodule_import0x200x2A0x2F = 0;
 const u64 wasm2c_test_max_0x5Cmodule_import0x200x2A0x2F = 65536;
 const u8 wasm2c_test_is64_0x5Cmodule_import0x200x2A0x2F = 0;
+const u32 wasm2c_test_pagesize_0x5Cmodule_import0x200x2A0x2F = 65536;
 
 void wasm2c_test_instantiate(w2c_test* instance, struct w2c_0x5Cmodule* w2c_0x5Cmodule_instance) {
   assert(wasm_rt_is_initialized());
diff --git a/test/wasm2c/hello.txt b/test/wasm2c/hello.txt
@@ -845,7 +845,7 @@ static const u8 data_segment_data_w2c_test_d0[] = {
 };
 
 static void init_memories(w2c_test* instance) {
-  wasm_rt_allocate_memory(&instance->w2c_memory, 1, 65536, 0);
+  wasm_rt_allocate_memory(&instance->w2c_memory, 1, 65536, 0, 65536);
   LOAD_DATA(instance->w2c_memory, 8u, data_segment_data_w2c_test_d0, 14);
 }
 
diff --git a/test/wasm2c/spec/custom-page-sizes/custom-page-sizes-invalid.txt b/test/wasm2c/spec/custom-page-sizes/custom-page-sizes-invalid.txt
@@ -0,0 +1,6 @@
+;;; TOOL: run-spec-wasm2c
+;;; ARGS*: --enable-custom-page-sizes --enable-multi-memory
+;;; STDIN_FILE: third_party/testsuite/proposals/custom-page-sizes/custom-page-sizes-invalid.wast
+(;; STDOUT ;;;
+0/0 tests passed.
+;;; STDOUT ;;)
diff --git a/test/wasm2c/spec/custom-page-sizes/custom-page-sizes.txt b/test/wasm2c/spec/custom-page-sizes/custom-page-sizes.txt
@@ -0,0 +1,6 @@
+;;; TOOL: run-spec-wasm2c
+;;; ARGS*: --enable-custom-page-sizes --enable-multi-memory
+;;; STDIN_FILE: third_party/testsuite/proposals/custom-page-sizes/custom-page-sizes.wast
+(;; STDOUT ;;;
+24/24 tests passed.
+;;; STDOUT ;;)
diff --git a/wasm2c/README.md b/wasm2c/README.md
@@ -297,13 +297,16 @@ typedef struct {
 
 Next is the definition of a memory instance. The `data` field is a pointer to
 `size` bytes of linear memory. The `size` field of `wasm_rt_memory_t` is the
-current size of the memory instance in bytes, whereas `pages` is the current
-size in pages (65536 bytes.) `max_pages` is the maximum number of pages as
-specified by the module, or `0xffffffff` if there is no limit.
+current size of the memory instance in bytes, `pages` is the current
+size in pages, and `page_size` contains the page size in bytes (65,536 by default).
+`max_pages` is the maximum number of pages specified by the module or allowed
+by the memory index type (`is64` is true for memories that can grow to 2^64 bytes;
+`false` for memories limited to 2^32 bytes).
 
 ```c
 typedef struct {
   uint8_t* data;
+  uint32_t page_size;
   uint64_t pages, max_pages;
   uint64_t size;
   bool is64;
@@ -353,10 +356,10 @@ bool wasm_rt_is_initialized(void);
 void wasm_rt_free(void);
 void wasm_rt_trap(wasm_rt_trap_t) __attribute__((noreturn));
 const char* wasm_rt_strerror(wasm_rt_trap_t trap);
-void wasm_rt_allocate_memory(wasm_rt_memory_t*, uint32_t initial_pages, uint32_t max_pages, bool is64);
+void wasm_rt_allocate_memory(wasm_rt_memory_t*, uint32_t initial_pages, uint32_t max_pages, bool is64, uint32_t page_size);
 uint32_t wasm_rt_grow_memory(wasm_rt_memory_t*, uint32_t pages);
 void wasm_rt_free_memory(wasm_rt_memory_t*);
-void wasm_rt_allocate_memory_shared(wasm_rt_shared_memory_t*, uint32_t initial_pages, uint32_t max_pages, bool is64);
+void wasm_rt_allocate_memory_shared(wasm_rt_shared_memory_t*, uint32_t initial_pages, uint32_t max_pages, bool is64, uint32_t page_size);
 uint32_t wasm_rt_grow_memory_shared(wasm_rt_shared_memory_t*, uint32_t pages);
 void wasm_rt_free_memory_shared(wasm_rt_shared_memory_t*);
 void wasm_rt_allocate_funcref_table(wasm_rt_table_t*, uint32_t elements, uint32_t max_elements);
@@ -381,10 +384,12 @@ with `WASM_RT_TRAP_HANDLER` defined to the name of a trap handler function. The
 handler function should be a function taking a `wasm_rt_trap_t` as a parameter
 and returning `void`. e.g. `-DWASM_RT_TRAP_HANDLER=my_trap_handler`
 
-`wasm_rt_allocate_memory` initializes a memory instance, and allocates at least
-enough space for the given number of initial pages. The memory must be cleared
-to zero. The `is64` parameter indicates if the memory is indexed with
-an i32 or i64 address.
+`wasm_rt_allocate_memory` initializes a memory instance, and allocates
+at least enough space for the given number of initial pages, each of
+size `page_size` (which must be `WASM_DEFAULT_PAGE_SIZE`, equal to 64
+KiB, unless using the custom-page-sizes feature). The memory must be
+cleared to zero. The `is64` parameter indicates if the memory is
+indexed with an i32 or i64 address.
 
 `wasm_rt_grow_memory` must grow the given memory instance by the given number of
 pages. If there isn't enough memory to do so, or the new page count would be
@@ -399,7 +404,7 @@ arguments and returning `void` . e.g.
 `wasm_rt_free_memory` frees the memory instance.
 
 `wasm_rt_allocate_memory_shared` initializes a memory instance that can be
-shared by different Wasm threads. It's operation is otherwise similar to
+shared by different Wasm threads. Its operation is otherwise similar to
 `wasm_rt_allocate_memory`.
 
 `wasm_rt_grow_memory_shared` must grow the given shared memory instance by the
@@ -658,8 +663,8 @@ int main(int argc, char** argv) {
 
   /* Create two `host` instances to store the memory and current string */
   w2c_host host_1, host_2;
-  wasm_rt_allocate_memory(&host_1.memory, 1, 1, false);
-  wasm_rt_allocate_memory(&host_2.memory, 1, 1, false);
+  wasm_rt_allocate_memory(&host_1.memory, 1, 1, false, WASM_DEFAULT_PAGE_SIZE);
+  wasm_rt_allocate_memory(&host_2.memory, 1, 1, false, WASM_DEFAULT_PAGE_SIZE);
 
   /* Construct the `rot13` module instances */
   w2c_rot13 rot13_1, rot13_2;
diff --git a/wasm2c/examples/rot13/main.c b/wasm2c/examples/rot13/main.c
@@ -42,7 +42,7 @@ int main(int argc, char** argv) {
   /* Create a structure to store the memory and current string, allocating 1
      page of Wasm memory (64 KiB) that the rot13 module instance will import. */
   struct w2c_host host;
-  wasm_rt_allocate_memory(&host.memory, 1, 1, false);
+  wasm_rt_allocate_memory(&host.memory, 1, 1, false, WASM_DEFAULT_PAGE_SIZE);
 
   // Construct an instance of the `rot13` module, which imports from the host.
   w2c_rot13 rot13;
diff --git a/wasm2c/wasm-rt-mem-impl-helper.inc b/wasm2c/wasm-rt-mem-impl-helper.inc
@@ -63,21 +63,28 @@
 
 #endif
 
+bool MEMORY_API_NAME(wasm_rt_memory_is_default32)(const MEMORY_TYPE* memory) {
+  return memory->page_size == WASM_DEFAULT_PAGE_SIZE && !memory->is64;
+}
+
 void MEMORY_API_NAME(wasm_rt_allocate_memory)(MEMORY_TYPE* memory,
                                               uint64_t initial_pages,
                                               uint64_t max_pages,
-                                              bool is64) {
-  uint64_t byte_length = initial_pages * WASM_PAGE_SIZE;
+                                              bool is64,
+                                              uint32_t page_size) {
+  uint64_t byte_length = initial_pages * page_size;
   memory->size = byte_length;
   memory->pages = initial_pages;
   memory->max_pages = max_pages;
   memory->is64 = is64;
+  memory->page_size = page_size;
   MEMORY_LOCK_VAR_INIT(memory->mem_lock);
 
-  if (WASM_RT_USE_MMAP && !is64) {
+  if (WASM_RT_USE_MMAP &&
+      MEMORY_API_NAME(wasm_rt_memory_is_default32)(memory)) {
 #if WASM_RT_USE_MMAP  // mmap-related functions don't exist unless this is set
     const uint64_t mmap_size =
-        get_alloc_size_for_mmap(memory->max_pages, memory->is64);
+        get_alloc_size_for_mmap_default32(memory->max_pages);
     void* addr = os_mmap(mmap_size);
     if (!addr) {
       os_print_last_error("os_mmap failed.");
@@ -105,11 +112,12 @@ static uint64_t MEMORY_API_NAME(grow_memory_impl)(MEMORY_TYPE* memory,
   if (new_pages < old_pages || new_pages > memory->max_pages) {
     return (uint64_t)-1;
   }
-  uint64_t old_size = old_pages * WASM_PAGE_SIZE;
-  uint64_t new_size = new_pages * WASM_PAGE_SIZE;
-  uint64_t delta_size = delta * WASM_PAGE_SIZE;
+  uint64_t old_size = old_pages * memory->page_size;
+  uint64_t new_size = new_pages * memory->page_size;
+  uint64_t delta_size = delta * memory->page_size;
   MEMORY_CELL_TYPE new_data;
-  if (WASM_RT_USE_MMAP && !memory->is64) {
+  if (WASM_RT_USE_MMAP &&
+      MEMORY_API_NAME(wasm_rt_memory_is_default32)(memory)) {
 #if WASM_RT_USE_MMAP
     new_data = memory->data;
     int ret = os_mprotect((void*)(new_data + old_size), delta_size);
@@ -150,10 +158,11 @@ uint64_t MEMORY_API_NAME(wasm_rt_grow_memory)(MEMORY_TYPE* memory,
 }
 
 void MEMORY_API_NAME(wasm_rt_free_memory)(MEMORY_TYPE* memory) {
-  if (WASM_RT_USE_MMAP && !memory->is64) {
+  if (WASM_RT_USE_MMAP &&
+      MEMORY_API_NAME(wasm_rt_memory_is_default32)(memory)) {
 #if WASM_RT_USE_MMAP
     const uint64_t mmap_size =
-        get_alloc_size_for_mmap(memory->max_pages, memory->is64);
+        get_alloc_size_for_mmap_default32(memory->max_pages);
     os_munmap((void*)memory->data, mmap_size);  // ignore error
 #endif
   } else {
diff --git a/wasm2c/wasm-rt-mem-impl.c b/wasm2c/wasm-rt-mem-impl.c
@@ -25,8 +25,6 @@
 #include <sys/mman.h>
 #endif
 
-#define WASM_PAGE_SIZE 65536
-
 #ifdef WASM_RT_GROW_FAILED_HANDLER
 extern void WASM_RT_GROW_FAILED_HANDLER();
 #endif
@@ -112,7 +110,7 @@ static void os_print_last_error(const char* msg) {
   }
 }
 
-#else
+#else /* !_WIN32 */
 static void* os_mmap(size_t size) {
   int map_prot = PROT_NONE;
   int map_flags = MAP_ANONYMOUS | MAP_PRIVATE;
@@ -134,17 +132,16 @@ static void os_print_last_error(const char* msg) {
   perror(msg);
 }
 
-#endif
+#endif /* _WIN32 */
 
-static uint64_t get_alloc_size_for_mmap(uint64_t max_pages, bool is64) {
-  assert(!is64 && "memory64 is not yet compatible with WASM_RT_USE_MMAP");
+static uint64_t get_alloc_size_for_mmap_default32(uint64_t max_pages) {
 #if WASM_RT_MEMCHECK_GUARD_PAGES
   /* Reserve 8GiB. */
   const uint64_t max_size = 0x200000000ul;
   return max_size;
 #else
   if (max_pages != 0) {
-    const uint64_t max_size = max_pages * WASM_PAGE_SIZE;
+    const uint64_t max_size = max_pages * WASM_DEFAULT_PAGE_SIZE;
     return max_size;
   }
 
@@ -154,7 +151,7 @@ static uint64_t get_alloc_size_for_mmap(uint64_t max_pages, bool is64) {
 #endif
 }
 
-#endif
+#endif /* WASM_RT_USE_MMAP */
 
 // Include operations for memory
 #define WASM_RT_MEM_OPS
@@ -175,4 +172,3 @@ static uint64_t get_alloc_size_for_mmap(uint64_t max_pages, bool is64) {
 #undef WIN_MEMORY_LOCK_VAR_INIT
 #undef WIN_MEMORY_LOCK_AQUIRE
 #undef WIN_MEMORY_LOCK_RELEASE
-#undef WASM_PAGE_SIZE
diff --git a/wasm2c/wasm-rt.h b/wasm2c/wasm-rt.h

Original file line number	Diff line number	Diff line change
`@@ -845,7 +845,7 @@ static const u8 data_segment_data_w2c_test_d0[] = {`
`845`	`845`	`};`
`846`	`846`
`847`	`847`	`static void init_memories(w2c_test* instance) {`
`848`		`- wasm_rt_allocate_memory(&instance->w2c_memory, 1, 65536, 0);`
	`848`	`+ wasm_rt_allocate_memory(&instance->w2c_memory, 1, 65536, 0, 65536);`
`849`	`849`	`LOAD_DATA(instance->w2c_memory, 8u, data_segment_data_w2c_test_d0, 14);`
`850`	`850`	`}`
`851`	`851`