1 /*
2 Example of using `anyref` values.
3
4 You can build using cmake:
5
6 mkdir build && cd build && cmake .. && \
7 cmake --build . --target wasmtime-anyref
8 */
9
10 #include <assert.h>
11 #include <stdio.h>
12 #include <stdlib.h>
13 #include <string.h>
14 #include <wasm.h>
15 #include <wasmtime.h>
16
17 static void exit_with_error(const char *message, wasmtime_error_t *error,
18 wasm_trap_t *trap);
19
main()20 int main() {
21 bool ok = true;
22 // Create a new configuration with Wasm GC enabled.
23 printf("Initializing...\n");
24 wasm_config_t *config = wasm_config_new();
25 assert(config != NULL);
26 wasmtime_config_wasm_reference_types_set(config, true);
27 wasmtime_config_wasm_function_references_set(config, true);
28 wasmtime_config_wasm_gc_set(config, true);
29
30 // Create an *engine*, which is a compilation context, with our configured
31 // options.
32 wasm_engine_t *engine = wasm_engine_new_with_config(config);
33 assert(engine != NULL);
34
35 // With an engine we can create a *store* which is a group of wasm instances
36 // that can interact with each other.
37 wasmtime_store_t *store = wasmtime_store_new(engine, NULL, NULL);
38 assert(store != NULL);
39 wasmtime_context_t *context = wasmtime_store_context(store);
40
41 // Read our input file, which in this case is a wasm text file.
42 FILE *file = fopen("examples/anyref.wat", "r");
43 assert(file != NULL);
44 fseek(file, 0L, SEEK_END);
45 size_t file_size = ftell(file);
46 fseek(file, 0L, SEEK_SET);
47 wasm_byte_vec_t wat;
48 wasm_byte_vec_new_uninitialized(&wat, file_size);
49 if (fread(wat.data, file_size, 1, file) != 1) {
50 printf("> Error loading module!\n");
51 return 1;
52 }
53 fclose(file);
54
55 // Parse the wat into the binary wasm format
56 wasm_byte_vec_t wasm;
57 wasmtime_error_t *error = wasmtime_wat2wasm(wat.data, wat.size, &wasm);
58 if (error != NULL)
59 exit_with_error("failed to parse wat", error, NULL);
60 wasm_byte_vec_delete(&wat);
61
62 // Now that we've got our binary webassembly we can compile our module.
63 printf("Compiling module...\n");
64 wasmtime_module_t *module = NULL;
65 error = wasmtime_module_new(engine, (uint8_t *)wasm.data, wasm.size, &module);
66 wasm_byte_vec_delete(&wasm);
67 if (error != NULL)
68 exit_with_error("failed to compile module", error, NULL);
69
70 // Instantiate the module.
71 printf("Instantiating module...\n");
72 wasm_trap_t *trap = NULL;
73 wasmtime_instance_t instance;
74 error = wasmtime_instance_new(context, module, NULL, 0, &instance, &trap);
75 if (error != NULL || trap != NULL)
76 exit_with_error("failed to instantiate", error, trap);
77
78 printf("Creating new `anyref` from i31...\n");
79
80 // Create a new `anyref` value from an i31 (`i31ref` is a subtype of
81 // `anyref`).
82 wasmtime_anyref_t anyref;
83 wasmtime_anyref_from_i31(context, 1234, &anyref);
84 assert(!wasmtime_anyref_is_null(&anyref));
85
86 // The `anyref`'s inner i31 value should be 1234.
87 uint32_t i31val = 0;
88 bool is_i31 = wasmtime_anyref_i31_get_u(context, &anyref, &i31val);
89 assert(is_i31);
90 assert(i31val == 1234);
91
92 printf("Touching `anyref` table...\n");
93
94 wasmtime_extern_t item;
95
96 // Lookup the `table` export.
97 ok = wasmtime_instance_export_get(context, &instance, "table",
98 strlen("table"), &item);
99 assert(ok);
100 assert(item.kind == WASMTIME_EXTERN_TABLE);
101
102 // Set `table[3]` to our `anyref`.
103 wasmtime_val_t anyref_val;
104 anyref_val.kind = WASMTIME_ANYREF;
105 anyref_val.of.anyref = anyref;
106 error = wasmtime_table_set(context, &item.of.table, 3, &anyref_val);
107 if (error != NULL)
108 exit_with_error("failed to set table", error, NULL);
109
110 // `table[3]` should now be our `anyref`.
111 wasmtime_val_t elem;
112 ok = wasmtime_table_get(context, &item.of.table, 3, &elem);
113 assert(ok);
114 assert(elem.kind == WASMTIME_ANYREF);
115 is_i31 = false;
116 i31val = 0;
117 is_i31 = wasmtime_anyref_i31_get_u(context, &elem.of.anyref, &i31val);
118 assert(is_i31);
119 assert(i31val == 1234);
120 wasmtime_val_unroot(&elem);
121
122 printf("Touching `anyref` global...\n");
123
124 // Lookup the `global` export.
125 ok = wasmtime_instance_export_get(context, &instance, "global",
126 strlen("global"), &item);
127 assert(ok);
128 assert(item.kind == WASMTIME_EXTERN_GLOBAL);
129
130 // Set the global to our `anyref`.
131 error = wasmtime_global_set(context, &item.of.global, &anyref_val);
132 if (error != NULL)
133 exit_with_error("failed to set global", error, NULL);
134
135 // Get the global, and it should return our `anyref` again.
136 wasmtime_val_t global_val;
137 wasmtime_global_get(context, &item.of.global, &global_val);
138 assert(global_val.kind == WASMTIME_ANYREF);
139 is_i31 = false;
140 i31val = 0;
141 is_i31 = wasmtime_anyref_i31_get_u(context, &global_val.of.anyref, &i31val);
142 assert(is_i31);
143 assert(i31val == 1234);
144 wasmtime_val_unroot(&global_val);
145
146 printf("Passing `anyref` into func...\n");
147
148 // Lookup the `take_anyref` export.
149 ok = wasmtime_instance_export_get(context, &instance, "take_anyref",
150 strlen("take_anyref"), &item);
151 assert(ok);
152 assert(item.kind == WASMTIME_EXTERN_FUNC);
153
154 // And call it!
155 error = wasmtime_func_call(context, &item.of.func, &anyref_val, 1, NULL, 0,
156 &trap);
157 if (error != NULL || trap != NULL)
158 exit_with_error("failed to call function", error, trap);
159
160 printf("Getting `anyref` from func...\n");
161
162 // Lookup the `return_anyref` export.
163 ok = wasmtime_instance_export_get(context, &instance, "return_anyref",
164 strlen("return_anyref"), &item);
165 assert(ok);
166 assert(item.kind == WASMTIME_EXTERN_FUNC);
167
168 // And call it!
169 wasmtime_val_t results[1];
170 error =
171 wasmtime_func_call(context, &item.of.func, NULL, 0, results, 1, &trap);
172 if (error != NULL || trap != NULL)
173 exit_with_error("failed to call function", error, trap);
174
175 // `return_anyfunc` returns an `i31ref` that wraps `42`.
176 assert(results[0].kind == WASMTIME_ANYREF);
177 is_i31 = false;
178 i31val = 0;
179 is_i31 = wasmtime_anyref_i31_get_u(context, &results[0].of.anyref, &i31val);
180 assert(is_i31);
181 assert(i31val == 42);
182 wasmtime_val_unroot(&results[0]);
183 wasmtime_val_unroot(&anyref_val);
184
185 // We can GC any now-unused references to our anyref that the store is
186 // holding.
187 printf("GCing within the store...\n");
188 wasmtime_context_gc(context);
189
190 // Clean up after ourselves at this point
191 printf("All finished!\n");
192
193 wasmtime_store_delete(store);
194 wasmtime_module_delete(module);
195 wasm_engine_delete(engine);
196 return 0;
197 }
198
exit_with_error(const char * message,wasmtime_error_t * error,wasm_trap_t * trap)199 static void exit_with_error(const char *message, wasmtime_error_t *error,
200 wasm_trap_t *trap) {
201 fprintf(stderr, "error: %s\n", message);
202 wasm_byte_vec_t error_message;
203 if (error != NULL) {
204 wasmtime_error_message(error, &error_message);
205 wasmtime_error_delete(error);
206 } else {
207 wasm_trap_message(trap, &error_message);
208 wasm_trap_delete(trap);
209 }
210 fprintf(stderr, "%.*s\n", (int)error_message.size, error_message.data);
211 wasm_byte_vec_delete(&error_message);
212 exit(1);
213 }
214