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Implement RFC 11: Redesigning Wasmtime's APIs (#2897)

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Implement Wasmtime's new API as designed by RFC 11. This is quite a large commit which has had lots of discussion externally, so for more information it's best to read the RFC thread and the PR thread.
This commit is contained in:
Alex Crichton
2021-06-03 09:10:53 -05:00
committed by GitHub
parent a5a28b1c5b
commit 7a1b7cdf92
233 changed files with 13349 additions and 11997 deletions
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108
examples/externref.c
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@@ -42,8 +42,9 @@ int main() {
// With an engine we can create a *store* which is a long-lived group of wasm
// modules.
wasm_store_t *store = wasm_store_new(engine);
wasmtime_store_t *store = wasmtime_store_new(engine, NULL, NULL);
assert(store != NULL);
wasmtime_context_t *context = wasmtime_store_context(store);
// Read our input file, which in this case is a wasm text file.
FILE* file = fopen("examples/externref.wat", "r");
@@ -58,15 +59,15 @@ int main() {
// Parse the wat into the binary wasm format
wasm_byte_vec_t wasm;
wasmtime_error_t *error = wasmtime_wat2wasm(&wat, &wasm);
wasmtime_error_t *error = wasmtime_wat2wasm(wat.data, wat.size, &wasm);
if (error != NULL)
exit_with_error("failed to parse wat", error, NULL);
wasm_byte_vec_delete(&wat);
// Now that we've got our binary webassembly we can compile our module.
printf("Compiling module...\n");
wasm_module_t *module = NULL;
error = wasmtime_module_new(engine, &wasm, &module);
wasmtime_module_t *module = NULL;
error = wasmtime_module_new(engine, (uint8_t*) wasm.data, wasm.size, &module);
wasm_byte_vec_delete(&wasm);
if (error != NULL)
exit_with_error("failed to compile module", error, NULL);
@@ -74,104 +75,99 @@ int main() {
// Instantiate the module.
printf("Instantiating module...\n");
wasm_trap_t *trap = NULL;
wasm_instance_t *instance = NULL;
wasm_extern_vec_t imports = WASM_EMPTY_VEC;
error = wasmtime_instance_new(store, module, &imports, &instance, &trap);
if (instance == NULL)
wasmtime_instance_t instance;
error = wasmtime_instance_new(context, module, NULL, 0, &instance, &trap);
if (error != NULL || trap != NULL)
exit_with_error("failed to instantiate", error, trap);
printf("Creating new `externref`...\n");
// Create a new `externref` value.
//
// Note that if you need clean up for after the externref is reclaimed, you
// can use `wasmtime_externref_new_with_finalizer`.
wasm_val_t externref;
wasmtime_externref_new("Hello, World!", &externref);
assert(externref.kind == WASM_ANYREF);
// Note that the NULL here is a finalizer callback, but we don't need one for
// this example.
wasmtime_externref_t *externref = wasmtime_externref_new("Hello, World!", NULL);
// The `externref`'s wrapped data should be the string "Hello, World!".
void* data = NULL;
ok = wasmtime_externref_data(&externref, &data);
assert(ok);
void* data = wasmtime_externref_data(externref);
assert(strcmp((char*)data, "Hello, World!") == 0);
printf("Touching `externref` table...\n");
wasmtime_extern_t item;
// Lookup the `table` export.
wasm_extern_vec_t externs;
wasm_instance_exports(instance, &externs);
assert(externs.size == 3);
wasm_table_t *table = wasm_extern_as_table(externs.data[0]);
assert(table != NULL);
ok = wasmtime_instance_export_get(context, &instance, "table", strlen("table"), &item);
assert(ok);
assert(item.kind == WASMTIME_EXTERN_TABLE);
// Set `table[3]` to our `externref`.
wasm_val_t elem;
wasm_val_copy(&elem, &externref);
assert(elem.kind == WASM_ANYREF);
ok = wasm_table_set(table, 3, elem.of.ref);
assert(ok);
wasmtime_val_t externref_val;
externref_val.kind = WASMTIME_EXTERNREF;
externref_val.of.externref = externref;
error = wasmtime_table_set(context, &item.of.table, 3, &externref_val);
if (error != NULL)
exit_with_error("failed to set table", error, NULL);
// `table[3]` should now be our `externref`.
wasm_ref_delete(elem.of.ref);
elem.of.ref = wasm_table_get(table, 3);
assert(elem.of.ref != NULL);
assert(wasm_ref_same(elem.of.ref, externref.of.ref));
wasmtime_val_t elem;
ok = wasmtime_table_get(context, &item.of.table, 3, &elem);
assert(ok);
assert(elem.kind == WASMTIME_EXTERNREF);
assert(strcmp((char*)wasmtime_externref_data(elem.of.externref), "Hello, World!") == 0);
wasmtime_val_delete(&elem);
printf("Touching `externref` global...\n");
// Lookup the `global` export.
wasm_global_t *global = wasm_extern_as_global(externs.data[1]);
assert(global != NULL);
ok = wasmtime_instance_export_get(context, &instance, "global", strlen("global"), &item);
assert(ok);
assert(item.kind == WASMTIME_EXTERN_GLOBAL);
// Set the global to our `externref`.
wasm_global_set(global, &externref);
error = wasmtime_global_set(context, &item.of.global, &externref_val);
if (error != NULL)
exit_with_error("failed to set global", error, NULL);
// Get the global, and it should return our `externref` again.
wasm_val_t global_val;
wasm_global_get(global, &global_val);
assert(global_val.kind == WASM_ANYREF);
assert(wasm_ref_same(global_val.of.ref, externref.of.ref));
wasmtime_val_t global_val;
wasmtime_global_get(context, &item.of.global, &global_val);
assert(global_val.kind == WASMTIME_EXTERNREF);
assert(strcmp((char*)wasmtime_externref_data(elem.of.externref), "Hello, World!") == 0);
wasmtime_val_delete(&global_val);
printf("Calling `externref` func...\n");
// Lookup the `func` export.
wasm_func_t *func = wasm_extern_as_func(externs.data[2]);
assert(func != NULL);
ok = wasmtime_instance_export_get(context, &instance, "func", strlen("func"), &item);
assert(ok);
assert(item.kind == WASMTIME_EXTERN_FUNC);
// And call it!
wasm_val_t args[1] = { externref };
wasm_val_t results[1];
wasm_val_vec_t args_vec = WASM_ARRAY_VEC(args);
wasm_val_vec_t results_vec = WASM_ARRAY_VEC(results);
error = wasmtime_func_call(func, &args_vec, &results_vec, &trap);
wasmtime_val_t results[1];
error = wasmtime_func_call(context, &item.of.func, &externref_val, 1, results, 1, &trap);
if (error != NULL || trap != NULL)
exit_with_error("failed to call function", error, trap);
// `func` returns the same reference we gave it, so `results[0]` should be our
// `externref`.
assert(results[0].kind == WASM_ANYREF);
assert(wasm_ref_same(results[0].of.ref, externref.of.ref));
assert(results[0].kind == WASMTIME_EXTERNREF);
assert(strcmp((char*)wasmtime_externref_data(results[0].of.externref), "Hello, World!") == 0);
wasmtime_val_delete(&results[0]);
// We can GC any now-unused references to our externref that the store is
// holding.
printf("GCing within the store...\n");
wasmtime_store_gc(store);
wasmtime_context_gc(context);
// Clean up after ourselves at this point
printf("All finished!\n");
ret = 0;
wasm_val_delete(&results[0]);
wasm_val_delete(&global_val);
wasm_val_delete(&elem);
wasm_extern_vec_delete(&externs);
wasm_val_delete(&externref);
wasm_instance_delete(instance);
wasm_module_delete(module);
wasm_store_delete(store);
wasmtime_store_delete(store);
wasmtime_module_delete(module);
wasm_engine_delete(engine);
return ret;
return 0;
}
static void exit_with_error(const char *message, wasmtime_error_t *error, wasm_trap_t *trap) {