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Add Wasmtime-specific C API functions to return errors (#1467)

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* Add Wasmtime-specific C API functions to return errors

This commit adds new `wasmtime_*` symbols to the C API, many of which
mirror the existing counterparts in the `wasm.h` header. These APIs are
enhanced in a number of respects:

* Detailed error information is now available through a
  `wasmtime_error_t`. Currently this only exposes one function which is
  to extract a string version of the error.

* There is a distinction now between traps and errors during
  instantiation and function calling. Traps only happen if wasm traps,
  and errors can happen for things like runtime type errors when
  interacting with the API.

* APIs have improved safety with respect to embedders where the lengths
  of arrays are now taken as explicit parameters rather than assumed
  from other parameters.

* Handle trap updates

* Update C examples

* Fix memory.c compile on MSVC

* Update test assertions

* Refactor C slightly

* Bare-bones .NET update

* Remove bogus nul handling
This commit is contained in:
Alex Crichton
2020-04-06 15:13:06 -05:00
committed by GitHub
parent 78c548dc8f
commit bd374fd6fc
30 changed files with 817 additions and 403 deletions
Download Patch File Download Diff File Expand all files Collapse all files

85
examples/memory.c
View File

@@ -28,6 +28,7 @@ originally
#include <wasm.h>
#include <wasmtime.h>
static void exit_with_error(const char *message, wasmtime_error_t *error, wasm_trap_t *trap);
wasm_memory_t* get_export_memory(const wasm_extern_vec_t* exports, size_t i) {
if (exports->size <= i || !wasm_extern_as_memory(exports->data[i])) {
@@ -53,21 +54,25 @@ void check(bool success) {
}
}
void check_call(wasm_func_t* func, wasm_val_t args[], int32_t expected) {
void check_call(wasm_func_t* func, wasm_val_t args[], size_t num_args, int32_t expected) {
wasm_val_t results[1];
if (wasm_func_call(func, args, results) || results[0].of.i32 != expected) {
wasm_trap_t *trap = NULL;
wasmtime_error_t *error = wasmtime_func_call(func, args, num_args, results, 1, &trap);
if (error != NULL || trap != NULL)
exit_with_error("failed to call function", error, trap);
if (results[0].of.i32 != expected) {
printf("> Error on result\n");
exit(1);
}
}
void check_call0(wasm_func_t* func, int32_t expected) {
check_call(func, NULL, expected);
check_call(func, NULL, 0, expected);
}
void check_call1(wasm_func_t* func, int32_t arg, int32_t expected) {
wasm_val_t args[] = { {.kind = WASM_I32, .of = {.i32 = arg}} };
check_call(func, args, expected);
check_call(func, args, 1, expected);
}
void check_call2(wasm_func_t* func, int32_t arg1, int32_t arg2, int32_t expected) {
@@ -75,14 +80,14 @@ void check_call2(wasm_func_t* func, int32_t arg1, int32_t arg2, int32_t expected
{.kind = WASM_I32, .of = {.i32 = arg1}},
{.kind = WASM_I32, .of = {.i32 = arg2}}
};
check_call(func, args, expected);
check_call(func, args, 2, expected);
}
void check_ok(wasm_func_t* func, wasm_val_t args[]) {
if (wasm_func_call(func, args, NULL)) {
printf("> Error on result, expected empty\n");
exit(1);
}
void check_ok(wasm_func_t* func, wasm_val_t args[], size_t num_args) {
wasm_trap_t *trap = NULL;
wasmtime_error_t *error = wasmtime_func_call(func, args, num_args, NULL, 0, &trap);
if (error != NULL || trap != NULL)
exit_with_error("failed to call function", error, trap);
}
void check_ok2(wasm_func_t* func, int32_t arg1, int32_t arg2) {
@@ -90,13 +95,17 @@ void check_ok2(wasm_func_t* func, int32_t arg1, int32_t arg2) {
{.kind = WASM_I32, .of = {.i32 = arg1}},
{.kind = WASM_I32, .of = {.i32 = arg2}}
};
check_ok(func, args);
check_ok(func, args, 2);
}
void check_trap(wasm_func_t* func, wasm_val_t args[]) {
void check_trap(wasm_func_t* func, wasm_val_t args[], size_t num_args, size_t num_results) {
wasm_val_t results[1];
wasm_trap_t* trap = wasm_func_call(func, args, results);
if (! trap) {
assert(num_results <= 1);
wasm_trap_t *trap = NULL;
wasmtime_error_t *error = wasmtime_func_call(func, args, num_args, results, num_results, &trap);
if (error != NULL)
exit_with_error("failed to call function", error, NULL);
if (trap == NULL) {
printf("> Error on result, expected trap\n");
exit(1);
}
@@ -105,7 +114,7 @@ void check_trap(wasm_func_t* func, wasm_val_t args[]) {
void check_trap1(wasm_func_t* func, int32_t arg) {
wasm_val_t args[1] = { {.kind = WASM_I32, .of = {.i32 = arg}} };
check_trap(func, args);
check_trap(func, args, 1, 1);
}
void check_trap2(wasm_func_t* func, int32_t arg1, int32_t arg2) {
@@ -113,7 +122,7 @@ void check_trap2(wasm_func_t* func, int32_t arg1, int32_t arg2) {
{.kind = WASM_I32, .of = {.i32 = arg1}},
{.kind = WASM_I32, .of = {.i32 = arg2}}
};
check_trap(func, args);
check_trap(func, args, 2, 0);
}
int main(int argc, const char* argv[]) {
@@ -140,30 +149,27 @@ int main(int argc, const char* argv[]) {
fclose(file);
// Parse the wat into the binary wasm format
wasm_byte_vec_t binary, error;
if (wasmtime_wat2wasm(&wat, &binary, &error) == 0) {
fprintf(stderr, "failed to parse wat %.*s\n", (int) error.size, error.data);
return 1;
}
wasm_byte_vec_t binary;
wasmtime_error_t *error = wasmtime_wat2wasm(&wat, &binary);
if (error != NULL)
exit_with_error("failed to parse wat", error, NULL);
wasm_byte_vec_delete(&wat);
// Compile.
printf("Compiling module...\n");
wasm_module_t* module = wasm_module_new(store, &binary);
if (!module) {
printf("> Error compiling module!\n");
return 1;
}
wasm_module_t* module = NULL;
error = wasmtime_module_new(store, &binary, &module);
if (error)
exit_with_error("failed to compile module", error, NULL);
wasm_byte_vec_delete(&binary);
// Instantiate.
printf("Instantiating module...\n");
wasm_instance_t* instance = wasm_instance_new(store, module, NULL, NULL);
if (!instance) {
printf("> Error instantiating module!\n");
return 1;
}
wasm_instance_t* instance = NULL;
wasm_trap_t *trap = NULL;
error = wasmtime_instance_new(module, NULL, 0, &instance, &trap);
if (!instance)
exit_with_error("failed to instantiate", error, trap);
// Extract export.
printf("Extracting exports...\n");
@@ -246,3 +252,18 @@ int main(int argc, const char* argv[]) {
printf("Done.\n");
return 0;
}
static void exit_with_error(const char *message, wasmtime_error_t *error, wasm_trap_t *trap) {
fprintf(stderr, "error: %s\n", message);
wasm_byte_vec_t error_message;
if (error != NULL) {
wasmtime_error_message(error, &error_message);
wasmtime_error_delete(error);
} else {
wasm_trap_message(trap, &error_message);
wasm_trap_delete(trap);
}
fprintf(stderr, "%.*s\n", (int) error_message.size, error_message.data);
wasm_byte_vec_delete(&error_message);
exit(1);
}