details:
https://github.com/nginx/njs/commit/eda6fa7d430619f646a2c969a267225306cff521
branches: master
commit: eda6fa7d430619f646a2c969a267225306cff521
user: Dmitry Volyntsev <xei...@nginx.com>
date: Tue, 15 Oct 2024 18:28:19 -0700
description:
Implemented lazy stack symbolization.
Previously, when an exception was thrown, the exception got 'stack'
property attached which contained the backtrace information about where
the exception happened. This could be a heavy operation and it was not
always needed.
To optimize it, the process is split into 2 phases. The first phase
collects all the necessary info about the current stack. The second
phase, where the stack symbolization happens, occurs only when this
property is referenced.
---
src/njs_error.c | 182 +++++++++++++++++++++++++++++++++++------------
src/njs_vm.h | 2 +-
src/test/njs_benchmark.c | 11 +++
3 files changed, 150 insertions(+), 45 deletions(-)
diff --git a/src/njs_error.c b/src/njs_error.c
index 376205d7..6a14d767 100644
--- a/src/njs_error.c
+++ b/src/njs_error.c
@@ -8,6 +8,15 @@
#include <njs_main.h>
+typedef struct {
+ union {
+ njs_function_t *function;
+ u_char *pc;
+ } u;
+ uint8_t native;
+} njs_stack_entry_t;
+
+
typedef struct {
njs_str_t name;
njs_str_t file;
@@ -16,7 +25,7 @@ typedef struct {
static njs_int_t njs_add_backtrace_entry(njs_vm_t *vm, njs_arr_t *stack,
- njs_native_frame_t *native_frame);
+ njs_stack_entry_t *se);
static njs_int_t njs_backtrace_to_string(njs_vm_t *vm, njs_arr_t *backtrace,
njs_str_t *dst);
@@ -87,22 +96,13 @@ njs_error_fmt_new(njs_vm_t *vm, njs_value_t *dst,
njs_object_type_t type,
static njs_int_t
-njs_error_stack_new(njs_vm_t *vm, njs_object_t *error, njs_value_t *retval)
+njs_error_stack_new(njs_vm_t *vm, njs_object_value_t *error)
{
- njs_int_t ret;
- njs_str_t string;
njs_arr_t *stack;
- njs_value_t value;
+ njs_stack_entry_t *se;
njs_native_frame_t *frame;
- njs_set_object(&value, error);
-
- ret = njs_error_to_string(vm, retval, &value);
- if (njs_slow_path(ret != NJS_OK)) {
- return ret;
- }
-
- stack = njs_arr_create(vm->mem_pool, 4, sizeof(njs_backtrace_entry_t));
+ stack = njs_arr_create(vm->mem_pool, 4, sizeof(njs_stack_entry_t));
if (njs_slow_path(stack == NULL)) {
return NJS_ERROR;
}
@@ -110,10 +110,20 @@ njs_error_stack_new(njs_vm_t *vm, njs_object_t *error,
njs_value_t *retval)
frame = vm->top_frame;
for ( ;; ) {
- if ((frame->native || frame->pc != NULL)
- && njs_add_backtrace_entry(vm, stack, frame) != NJS_OK)
- {
- break;
+ if (frame->native || frame->pc != NULL) {
+ se = njs_arr_add(stack);
+ if (njs_slow_path(se == NULL)) {
+ return NJS_ERROR;
+ }
+
+ se->native = frame->native;
+
+ if (se->native) {
+ se->u.function = frame->function;
+
+ } else {
+ se->u.pc = frame->pc;
+ }
}
frame = frame->previous;
@@ -123,25 +133,16 @@ njs_error_stack_new(njs_vm_t *vm, njs_object_t *error,
njs_value_t *retval)
}
}
- njs_string_get(retval, &string);
-
- ret = njs_backtrace_to_string(vm, stack, &string);
-
- njs_arr_destroy(stack);
-
- if (njs_slow_path(ret != NJS_OK)) {
- return ret;
- }
+ njs_data(&error->value) = stack;
- return njs_string_create(vm, retval, string.start, string.length);
+ return NJS_OK;
}
njs_int_t
njs_error_stack_attach(njs_vm_t *vm, njs_value_t value)
{
- njs_int_t ret;
- njs_value_t stack;
+ njs_int_t ret;
if (njs_slow_path(!njs_is_error(&value))
|| njs_object(&value)->stack_attached)
@@ -153,7 +154,7 @@ njs_error_stack_attach(njs_vm_t *vm, njs_value_t value)
return NJS_OK;
}
- ret = njs_error_stack_new(vm, njs_object(&value), &stack);
+ ret = njs_error_stack_new(vm, value.data.u.object_value);
if (njs_slow_path(ret != NJS_OK)) {
njs_internal_error(vm, "njs_error_stack_new() failed");
return NJS_ERROR;
@@ -161,10 +162,7 @@ njs_error_stack_attach(njs_vm_t *vm, njs_value_t value)
njs_object(&value)->stack_attached = 1;
- return njs_object_prop_define(vm, &value,
- njs_value_arg(&njs_error_stack_string),
- &stack, NJS_OBJECT_PROP_VALUE_CW,
- NJS_STACK_HASH);
+ return NJS_OK;
}
@@ -194,16 +192,20 @@ njs_error_alloc(njs_vm_t *vm, njs_object_t *proto, const
njs_value_t *name,
njs_int_t ret;
njs_object_t *error;
njs_object_prop_t *prop;
+ njs_object_value_t *ov;
njs_lvlhsh_query_t lhq;
- error = njs_mp_alloc(vm->mem_pool, sizeof(njs_object_t));
- if (njs_slow_path(error == NULL)) {
+ ov = njs_mp_alloc(vm->mem_pool, sizeof(njs_object_value_t));
+ if (njs_slow_path(ov == NULL)) {
goto memory_error;
}
+ njs_set_data(&ov->value, NULL, NJS_DATA_TAG_ANY);
+
+ error = &ov->object;
njs_lvlhsh_init(&error->hash);
njs_lvlhsh_init(&error->shared_hash);
- error->type = NJS_OBJECT;
+ error->type = NJS_OBJECT_VALUE;
error->shared = 0;
error->extensible = 1;
error->fast_array = 0;
@@ -485,15 +487,18 @@ const njs_object_init_t
njs_aggregate_error_constructor_init = {
void
njs_memory_error_set(njs_vm_t *vm, njs_value_t *value)
{
- njs_object_t *object;
+ njs_object_t *object;
+ njs_object_value_t *ov;
- object = &vm->memory_error_object;
+ ov = &vm->memory_error_object;
+ njs_set_data(&ov->value, NULL, NJS_DATA_TAG_ANY);
+ object = &ov->object;
njs_lvlhsh_init(&object->hash);
njs_lvlhsh_init(&object->shared_hash);
object->__proto__ = njs_vm_proto(vm, NJS_OBJ_TYPE_INTERNAL_ERROR);
object->slots = NULL;
- object->type = NJS_OBJECT;
+ object->type = NJS_OBJECT_VALUE;
object->shared = 1;
/*
@@ -691,6 +696,92 @@ njs_error_prototype_to_string(njs_vm_t *vm, njs_value_t
*args, njs_uint_t nargs,
}
+static njs_int_t
+njs_error_prototype_stack(njs_vm_t *vm, njs_object_prop_t *prop,
+ njs_value_t *value, njs_value_t *setval, njs_value_t *retval)
+{
+ njs_int_t ret;
+ njs_str_t string;
+ njs_arr_t *stack, *backtrace;
+ njs_uint_t i;
+ njs_value_t rv, *stackval;
+ njs_stack_entry_t *se;
+
+ if (retval != NULL) {
+ if (!njs_is_error(value)) {
+ njs_set_undefined(retval);
+ return NJS_DECLINED;
+ }
+
+ stackval = njs_object_value(value);
+
+ if (setval != NULL) {
+ njs_value_assign(stackval, setval);
+ return NJS_OK;
+ }
+
+ if (!njs_is_data(stackval, NJS_DATA_TAG_ANY)) {
+ njs_value_assign(retval, stackval);
+ return NJS_OK;
+ }
+
+ stack = njs_data(stackval);
+ if (stack == NULL) {
+ njs_set_undefined(retval);
+ return NJS_OK;
+ }
+
+ se = stack->start;
+
+ backtrace = njs_arr_create(vm->mem_pool, stack->items,
+ sizeof(njs_backtrace_entry_t));
+ if (njs_slow_path(backtrace == NULL)) {
+ return NJS_ERROR;
+ }
+
+ for (i = 0; i < stack->items; i++) {
+ if (njs_add_backtrace_entry(vm, backtrace, &se[i]) != NJS_OK) {
+ return NJS_ERROR;
+ }
+ }
+
+ ret = njs_error_to_string2(vm, &rv, value, 0);
+ if (njs_slow_path(ret != NJS_OK)) {
+ return ret;
+ }
+
+ njs_string_get(&rv, &string);
+
+ ret = njs_backtrace_to_string(vm, backtrace, &string);
+
+ njs_arr_destroy(backtrace);
+ njs_arr_destroy(stack);
+
+ if (njs_slow_path(ret != NJS_OK)) {
+ return ret;
+ }
+
+ ret = njs_string_create(vm, stackval, string.start, string.length);
+ if (njs_slow_path(ret != NJS_OK)) {
+ return ret;
+ }
+
+ njs_value_assign(retval, stackval);
+
+ return NJS_OK;
+ }
+
+ /* Delete. */
+
+ if (njs_is_error(value)) {
+ stackval = njs_object_value(value);
+ njs_set_data(stackval, NULL, NJS_DATA_TAG_ANY);
+ }
+
+ return NJS_OK;
+}
+
+
njs_int_t
njs_error_to_string(njs_vm_t *vm, njs_value_t *retval, const njs_value_t
*error)
{
@@ -717,6 +808,9 @@ static const njs_object_prop_t
njs_error_prototype_properties[] =
NJS_DECLARE_PROP_NATIVE("valueOf", njs_error_prototype_value_of, 0, 0),
NJS_DECLARE_PROP_NATIVE("toString", njs_error_prototype_to_string, 0, 0),
+
+ NJS_DECLARE_PROP_HANDLER("stack", njs_error_prototype_stack,
+ 0, 0, NJS_OBJECT_PROP_VALUE_CW),
};
@@ -986,14 +1080,14 @@ const njs_object_type_init_t
njs_aggregate_error_type_init = {
static njs_int_t
njs_add_backtrace_entry(njs_vm_t *vm, njs_arr_t *stack,
- njs_native_frame_t *native_frame)
+ njs_stack_entry_t *se)
{
njs_int_t ret;
njs_vm_code_t *code;
njs_function_t *function;
njs_backtrace_entry_t *be;
- function = native_frame->function;
+ function = se->native ? se->u.function : NULL;
if (function != NULL && function->bound != NULL) {
/* Skip. */
@@ -1019,7 +1113,7 @@ njs_add_backtrace_entry(njs_vm_t *vm, njs_arr_t *stack,
return NJS_OK;
}
- code = njs_lookup_code(vm, native_frame->pc);
+ code = njs_lookup_code(vm, se->u.pc);
if (code != NULL) {
be->name = code->name;
@@ -1028,7 +1122,7 @@ njs_add_backtrace_entry(njs_vm_t *vm, njs_arr_t *stack,
be->name = njs_entry_anonymous;
}
- be->line = njs_lookup_line(code->lines, native_frame->pc -
code->start);
+ be->line = njs_lookup_line(code->lines, se->u.pc - code->start);
if (!vm->options.quiet) {
be->file = code->file;
}
diff --git a/src/njs_vm.h b/src/njs_vm.h
index 6d09caf8..a3f2b5a9 100644
--- a/src/njs_vm.h
+++ b/src/njs_vm.h
@@ -165,7 +165,7 @@ struct njs_vm_s {
* MemoryError is statically allocated immutable Error object
* with the InternalError prototype.
*/
- njs_object_t memory_error_object;
+ njs_object_value_t memory_error_object;
njs_object_t string_object;
njs_object_t global_object;
diff --git a/src/test/njs_benchmark.c b/src/test/njs_benchmark.c
index 6ca83e82..98c618c8 100644
--- a/src/test/njs_benchmark.c
+++ b/src/test/njs_benchmark.c
@@ -116,6 +116,7 @@ njs_benchmark_test(njs_vm_t *parent, njs_opts_t *opts,
njs_value_t *report,
njs_vm_opt_init(&options);
+ options.backtrace = 1;
options.addons = njs_benchmark_addon_external_modules;
vm = NULL;
@@ -468,6 +469,16 @@ static njs_benchmark_test_t njs_test[] =
njs_str("$shared.method('YES')"),
njs_str("shared"),
1000 },
+
+ { "exception",
+ njs_str("function f() { try { throw new Error('test') } catch (e) {
return e.message } } [f].map(v=>v())[0]"),
+ njs_str("test"),
+ 10000 },
+
+ { "exception.stack",
+ njs_str("function f() { try { throw new Error('test') } catch (e) {
return e.stack } } [f].map(v=>v())[0]"),
+ njs_str("Error: test\n at f (:1)\n at anonymous (:1)\n at
Array.prototype.map (native)\n at main (:1)\n"),
+ 100 },
};
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