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async stack traces #1803

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69 changes: 69 additions & 0 deletions api-test.c
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Original file line number Diff line number Diff line change
Expand Up @@ -2228,8 +2228,77 @@ static void new_context_low_memory(void)
assert(ok < all); // ...but not all
}

static JSValue async_stack_failing_job(JSContext *ctx, int argc, JSValueConst *argv)
{
return JS_ThrowTypeError(ctx, "nested job failure");
}

static JSValue async_stack_pump(JSContext *ctx, JSValueConst this_val,
int argc, JSValueConst *argv)
{
JSContext *job_ctx = NULL;
bool failure = JS_ToBool(ctx, argv[0]);
/* Queue the failure behind the inner callback, before it enqueues more jobs. */
if (!failure)
assert(JS_EnqueueJob(ctx, async_stack_failing_job, 0, NULL) == 0);
int ret = JS_ExecutePendingJob(JS_GetRuntime(ctx), &job_ctx);
assert(job_ctx == ctx);
assert(ret == (failure ? -1 : 1));
if (failure)
JS_FreeValue(ctx, JS_GetException(ctx));
return JS_UNDEFINED;
}

static void async_stack_reentrant_jobs(void)
{
JSRuntime *rt = new_runtime();
JSContext *ctx = JS_NewContext(rt), *job_ctx;
JSValue global = JS_GetGlobalObject(ctx), promise, result;
int ret, jobs = 0;

assert(JS_SetPropertyStr(ctx, global, "pump",
JS_NewCFunction(ctx, async_stack_pump, "pump", 1)) >= 0);
JS_FreeValue(ctx, global);
promise = eval(ctx,
"Error.prepareStackTrace = (_, frames) => frames;"
"const snapshots = [];"
"function capture() {"
" return new Error().stack"
" .filter(f => f.isAsync() && f.getPromiseIndex() === null)"
" .map(f => f.getFunctionName()).join(',');"
"}"
"const outer = Promise.resolve().then(function outerCallback() {"
" snapshots.push(capture());"
" pump(false);"
" snapshots.push(capture());"
" pump(true);"
" snapshots.push(capture());"
"});"
"const inner = Promise.resolve().then(function innerCallback() {"
" snapshots.push(capture());"
"});"
"async function outerWait() { await outer; }"
"async function innerWait() { await inner; }"
"Promise.all([outerWait(), innerWait()]);");
assert(JS_IsPromise(promise));
while ((ret = JS_ExecutePendingJob(rt, &job_ctx)) != 0) {
assert(ret == 1);
assert(++jobs < 20);
}
assert(JS_PromiseState(ctx, promise) == JS_PROMISE_FULFILLED);
JS_FreeValue(ctx, promise);
result = eval(ctx,
"snapshots.join('|') === 'outerWait|innerWait|outerWait|outerWait' &&"
"capture() === ''");
assert(JS_IsBool(result) && JS_ToBool(ctx, result));
JS_FreeValue(ctx, result);
JS_FreeContext(ctx);
JS_FreeRuntime(rt);
}

int main(void)
{
async_stack_reentrant_jobs();
cfunctions();
sync_call();
async_call();
Expand Down
176 changes: 172 additions & 4 deletions quickjs.c
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Original file line number Diff line number Diff line change
Expand Up @@ -378,6 +378,7 @@ struct JSRuntime {
bool in_free;

struct JSStackFrame *current_stack_frame;
struct JSJobEntry *current_job; /* borrowed while executing the job */

JSInterruptHandler *interrupt_handler;
void *interrupt_opaque;
Expand Down Expand Up @@ -1213,6 +1214,9 @@ typedef struct JSCallSiteData {
JSValue func_name;
bool native;
bool constructor;
bool is_async;
bool is_promise_all;
int promise_index;
int line_num;
int col_num;
} JSCallSiteData;
Expand Down Expand Up @@ -2526,7 +2530,7 @@ JSContext *JS_GetPendingJobContext(JSRuntime *rt)
int JS_ExecutePendingJob(JSRuntime *rt, JSContext **pctx)
{
JSContext *ctx;
JSJobEntry *e;
JSJobEntry *e, *prev_job;
JSValue res;
int i, ret;

Expand All @@ -2539,7 +2543,10 @@ int JS_ExecutePendingJob(JSRuntime *rt, JSContext **pctx)
e = list_entry(rt->job_list.next, JSJobEntry, link);
list_del(&e->link);
ctx = e->ctx;
prev_job = rt->current_job;
rt->current_job = e;
res = e->job_func(e->ctx, e->argc, vc(e->argv));
rt->current_job = prev_job;
for(i = 0; i < e->argc; i++)
JS_FreeValue(ctx, e->argv[i]);
if (JS_IsException(res))
Expand Down Expand Up @@ -8185,13 +8192,20 @@ static bool can_store_error_stack(JSValueConst obj)
#define JS_BACKTRACE_FLAG_SINGLE_LEVEL (1 << 1)
#define JS_BACKTRACE_FLAG_FILTER_FUNC (1 << 2)

static JSStackFrame *js_async_stack_frame(JSContext *ctx, JSStackFrame *sf,
JSJobEntry *job, JSCallSiteData *csd,
DynBuf *dbuf, uint32_t *count, int limit);

/* if filename != NULL, an additional level is added with the filename
and line number information (used for parse error). */
static void build_backtrace(JSContext *ctx, JSValueConst error_val,
JSValueConst filter_func, const char *filename,
int line_num, int col_num, int backtrace_flags)
{
JSStackFrame *sf, *sf_start;
JSStackFrame *async_sf = NULL;
JSJobEntry *job = ctx->rt->current_job;
bool is_async = false;
JSValue stack, prepare, saved_exception, error_obj;
DynBuf dbuf;
const char *func_name_str;
Expand Down Expand Up @@ -8275,10 +8289,10 @@ static void build_backtrace(JSContext *ctx, JSValueConst error_val,
}
}

for (sf = sf_start; sf != NULL && i < stack_trace_limit; sf = sf->prev_frame) {
for (sf = sf_start; sf != NULL && i < stack_trace_limit;) {
if (backtrace_flags & JS_BACKTRACE_FLAG_SKIP_FIRST_LEVEL) {
backtrace_flags &= ~JS_BACKTRACE_FLAG_SKIP_FIRST_LEVEL;
continue;
goto next;
}

p = JS_VALUE_GET_OBJ(sf->cur_func);
Expand All @@ -8292,14 +8306,15 @@ static void build_backtrace(JSContext *ctx, JSValueConst error_val,

if (has_prepare) {
js_new_callsite_data(ctx, &csd[i], sf);
csd[i].is_async = is_async;
} else {
/* func_name_str is UTF-8 encoded if needed */
func_name_str = get_func_name(ctx, sf->cur_func);
if (!func_name_str || func_name_str[0] == '\0')
str1 = "<anonymous>";
else
str1 = func_name_str;
dbuf_printf(&dbuf, " at %s", str1);
dbuf_printf(&dbuf, " at %s%s", is_async ? "async " : "", str1);
JS_FreeCString(ctx, func_name_str);

if (b && sf->cur_pc) {
Expand Down Expand Up @@ -8330,6 +8345,21 @@ static void build_backtrace(JSContext *ctx, JSValueConst error_val,
/* stop backtrace if JS_EVAL_FLAG_BACKTRACE_BARRIER was used */
if (backtrace_barrier)
break;
next:
if (!is_async) {
/* Start with the outermost coroutine already on the native stack. */
if (js_class_has_bytecode(JS_VALUE_GET_OBJ(sf->cur_func)->class_id) &&
sf->cur_gc_obj)
async_sf = sf;
sf = sf->prev_frame;
if (sf)
continue;
sf = async_sf;
is_async = true;
}
sf = js_async_stack_frame(ctx, sf, job, has_prepare ? csd : NULL,
has_prepare ? NULL : &dbuf, &i, stack_trace_limit);
job = NULL;
}
done:
if (has_prepare) {
Expand Down Expand Up @@ -55531,6 +55561,119 @@ typedef struct JSPromiseReactionData {
JSValue handler;
} JSPromiseReactionData;

static JSValue promise_reaction_job(JSContext *ctx, int argc, JSValueConst *argv);
static JSValue js_promise_all_resolve_element(JSContext *ctx, JSValueConst this_val,
int argc, JSValueConst *argv,
int magic, JSValueConst *func_data);

/* Return a borrowed promise without invoking user-defined resolving functions. */
static JSValue js_resolving_function_promise(JSValueConst func)
{
JSPromiseFunctionData *fd = JS_GetOpaque(func, JS_CLASS_PROMISE_RESOLVE_FUNCTION);
if (!fd)
fd = JS_GetOpaque(func, JS_CLASS_PROMISE_REJECT_FUNCTION);
return fd ? fd->promise : JS_UNDEFINED;
}

/* Follow existing promise links without retaining frames or running JS. */
static JSStackFrame *js_async_stack_frame(JSContext *ctx, JSStackFrame *sf,
JSJobEntry *job, JSCallSiteData *csd,
DynBuf *dbuf, uint32_t *count, int limit)
{
JSAsyncFunctionData *af;
JSAsyncGeneratorData *ag;
JSPromiseData *pd;
JSPromiseReactionData *rd;
JSCFunctionDataRecord *cd;
JSObject *p;
JSValue promise = JS_UNDEFINED;
struct list_head *head;
int depth;

/* A .then() callback or thenable may have no running async function. */
if (job) {
if (job->job_func == promise_reaction_job)
promise = js_resolving_function_promise(job->argv[0]);
else if (job->job_func == js_promise_resolve_thenable_job)
promise = job->argv[0];
if (!JS_IsUndefined(promise))
goto follow;
}
if (!sf || !sf->cur_gc_obj)
return NULL;
if (JS_GC_TYPE(sf->cur_gc_obj) == JS_GC_OBJ_TYPE_ASYNC_FUNCTION) {
af = (JSAsyncFunctionData *)sf->cur_gc_obj;
promise = js_resolving_function_promise(af->resolving_funcs[0]);
} else {
p = (JSObject *)sf->cur_gc_obj;
if (p->class_id != JS_CLASS_ASYNC_GENERATOR)
return NULL;
ag = p->u.async_generator_data;
if (list_empty(&ag->queue))
return NULL;
promise = list_entry(ag->queue.next, JSAsyncGeneratorRequest, link)->promise;
}
follow:
/* Bound traversal through forwarding links, which can form cycles. */
for (depth = 0; depth < 1024 && *count < limit; depth++) {
pd = JS_GetOpaque(promise, JS_CLASS_PROMISE);
if (!pd || pd->promise_state != JS_PROMISE_PENDING)
return NULL;
head = &pd->promise_reactions[0];
/* A shared promise has no unambiguous async caller. */
if (list_empty(head) || head->next->next != head)
return NULL;
rd = list_entry(head->next, JSPromiseReactionData, link);
af = JS_GetOpaque(rd->handler, JS_CLASS_ASYNC_FUNCTION_RESOLVE);
if (af && af->is_active && af->func_state.frame.cur_sp)
return &af->func_state.frame;
cd = JS_GetOpaque(rd->handler, JS_CLASS_C_FUNCTION_DATA);
if (cd && cd->func == js_async_generator_resolve_function) {
ag = JS_GetOpaque(cd->data[0], JS_CLASS_ASYNC_GENERATOR);
if (ag && ag->state == JS_ASYNC_GENERATOR_STATE_EXECUTING &&
ag->func_state.frame.cur_sp)
return &ag->func_state.frame;
}
/* any stores its element handler on the rejection reaction. */
if ((!cd || cd->func != js_promise_all_resolve_element) &&
!list_empty(&pd->promise_reactions[1])) {
JSPromiseReactionData *reject = list_entry(pd->promise_reactions[1].next,
JSPromiseReactionData, link);
cd = JS_GetOpaque(reject->handler, JS_CLASS_C_FUNCTION_DATA);
}
if (cd && cd->func == js_promise_all_resolve_element) {
static const char * const names[] = { "all", "allSettled", "any" };
int kind = cd->magic & 3;
int index = JS_VALUE_GET_INT(cd->data[1]);
if (csd) {
csd[*count] = (JSCallSiteData) {
.filename = JS_NULL,
.func = JS_UNDEFINED,
.func_name = JS_NewString(ctx, names[kind]),
.is_async = true,
.is_promise_all = kind == 0,
.promise_index = index,
.line_num = -1,
.col_num = -1,
};
if (JS_IsException(csd[*count].func_name))
csd[*count].func_name = JS_NULL;
} else {
dbuf_printf(dbuf, " at async Promise.%s (index %d)\n",
names[kind], index);
}
(*count)++;
promise = js_resolving_function_promise(cd->data[3]);
} else {
/* Promise adoption and any/race use the resolving function directly. */
promise = js_resolving_function_promise(rd->handler);
if (JS_IsUndefined(promise))
promise = js_resolving_function_promise(rd->resolving_funcs[0]);
}
}
return NULL;
}

JSPromiseStateEnum JS_PromiseState(JSContext *ctx, JSValueConst promise)
{
JSPromiseData *s = JS_GetOpaque(promise, JS_CLASS_PROMISE);
Expand Down Expand Up @@ -63534,6 +63677,9 @@ static void js_new_callsite_data(JSContext *ctx, JSCallSiteData *csd, JSStackFra
JSObject *p;

csd->constructor = sf->is_constructor;
csd->is_async = false;
csd->is_promise_all = false;
csd->promise_index = -1;
csd->func = js_dup(sf->cur_func);
/* func_name_str is UTF-8 encoded if needed */
func_name_str = get_func_name(ctx, sf->cur_func);
Expand Down Expand Up @@ -63574,6 +63720,9 @@ static void js_new_callsite_data2(JSContext *ctx, JSCallSiteData *csd, const cha
csd->func_name = JS_NULL;
csd->native = false;
csd->constructor = false;
csd->is_async = false;
csd->is_promise_all = false;
csd->promise_index = -1;
csd->line_num = line_num;
csd->col_num = col_num;
/* filename is UTF-8 encoded if needed (original argument to __JS_EvalInternal()) */
Expand Down Expand Up @@ -63609,6 +63758,22 @@ static JSValue js_callsite_isconstructor(JSContext *ctx, JSValueConst this_val,
return js_bool(csd->constructor);
}

static JSValue js_callsite_isasync(JSContext *ctx, JSValueConst this_val, int argc, JSValueConst *argv)
{
JSCallSiteData *csd = JS_GetOpaque2(ctx, this_val, JS_CLASS_CALL_SITE);
if (!csd)
return JS_EXCEPTION;
return js_bool(csd->is_async);
}

static JSValue js_callsite_ispromiseall(JSContext *ctx, JSValueConst this_val, int argc, JSValueConst *argv)
{
JSCallSiteData *csd = JS_GetOpaque2(ctx, this_val, JS_CLASS_CALL_SITE);
if (!csd)
return JS_EXCEPTION;
return js_bool(csd->is_promise_all);
}

static JSValue js_callsite_getnumber(JSContext *ctx, JSValueConst this_val, int argc, JSValueConst *argv, int magic)
{
JSCallSiteData *csd = JS_GetOpaque2(ctx, this_val, JS_CLASS_CALL_SITE);
Expand All @@ -63624,6 +63789,9 @@ static JSValue js_callsite_getnumber(JSContext *ctx, JSValueConst this_val, int
static const JSCFunctionListEntry js_callsite_proto_funcs[] = {
JS_CFUNC_DEF("isNative", 0, js_callsite_isnative),
JS_CFUNC_DEF("isConstructor", 0, js_callsite_isconstructor),
JS_CFUNC_DEF("isAsync", 0, js_callsite_isasync),
JS_CFUNC_DEF("isPromiseAll", 0, js_callsite_ispromiseall),
JS_CFUNC_MAGIC_DEF("getPromiseIndex", 0, js_callsite_getnumber, offsetof(JSCallSiteData, promise_index)),
JS_CFUNC_MAGIC_DEF("getFileName", 0, js_callsite_getfield, offsetof(JSCallSiteData, filename)),
JS_CFUNC_MAGIC_DEF("getFunction", 0, js_callsite_getfield, offsetof(JSCallSiteData, func)),
JS_CFUNC_MAGIC_DEF("getFunctionName", 0, js_callsite_getfield, offsetof(JSCallSiteData, func_name)),
Expand Down
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