MIRROR: javascript for 🐜's, a tiny runtime with big ambitions
introduce controlled GC safepoints
+46
-14
+6
include/gc.h
+6
include/gc.h
+1
include/internal.h
+1
include/internal.h
···
60
60
bool is_hoisting; // true during function declaration hoisting pass
61
61
uint64_t sym_counter; // counter for generating unique symbol IDs
62
62
bool needs_gc; // deferred GC flag, checked at statement boundaries
63
+
bool gc_safe; // true when GC is allowed to run (at safe points only)
63
64
jsoff_t gc_alloc_since; // bytes allocated since last GC
64
65
int eval_depth; // recursion depth of js_eval calls
65
66
int parse_depth; // recursion depth of parser (for stack overflow protection)
+16
-7
src/ant.c
+16
-7
src/ant.c
···
7384
7384
if (is_non_numeric(lu) || is_non_numeric(ru) || (vtype(lu) == T_STR && vtype(ru) == T_STR)) {
7385
7385
jsval_t l_str = coerce_to_str_concat(js, l);
7386
7386
if (is_err(l_str)) return l_str;
7387
+
jshdl_t lh = js_root(js, l_str);
7387
7388
jsval_t r_str = coerce_to_str_concat(js, r);
7389
+
l_str = js_deref(js, lh); js_unroot(js, lh);
7388
7390
if (is_err(r_str)) return r_str;
7389
7391
return do_string_op(js, op, l_str, r_str);
7390
7392
}
···
9517
9519
goto *dispatch[tok];
9518
9520
9519
9521
do_binop: {
9522
+
jshdl_t lh = js_root(js, lhs);
9520
9523
jsval_t rhs = js_expr_bp(js, bp + 1);
9524
+
lhs = js_deref(js, lh); js_unroot(js, lh);
9521
9525
if (is_err(rhs)) return rhs;
9522
9526
lhs = do_op(js, tok, lhs, rhs);
9523
9527
goto loop;
9524
9528
}
9525
9529
9526
9530
do_exp: {
9531
+
jshdl_t lh = js_root(js, lhs);
9527
9532
jsval_t rhs = js_expr_bp(js, bp);
9533
+
lhs = js_deref(js, lh); js_unroot(js, lh);
9528
9534
if (is_err(rhs)) return rhs;
9529
9535
lhs = do_op(js, TOK_EXP, lhs, rhs);
9530
9536
goto loop;
···
9534
9540
uint8_t flags = js->flags;
9535
9541
lhs = resolveprop(js, lhs);
9536
9542
if (js_truthy(js, lhs)) js->flags |= F_NOEXEC;
9543
+
jshdl_t lh = js_root(js, lhs);
9537
9544
jsval_t rhs = js_expr_bp(js, bp);
9545
+
lhs = js_deref(js, lh); js_unroot(js, lh);
9538
9546
if (!(flags & F_NOEXEC) && !js_truthy(js, lhs)) lhs = rhs;
9539
9547
js->flags = flags;
9540
9548
if (is_err(rhs)) return rhs;
···
9545
9553
uint8_t flags = js->flags;
9546
9554
lhs = resolveprop(js, lhs);
9547
9555
if (!js_truthy(js, lhs)) js->flags |= F_NOEXEC;
9556
+
jshdl_t lh = js_root(js, lhs);
9548
9557
jsval_t rhs = js_expr_bp(js, bp);
9558
+
lhs = js_deref(js, lh); js_unroot(js, lh);
9549
9559
if (!(flags & F_NOEXEC) && js_truthy(js, lhs)) lhs = rhs;
9550
9560
js->flags = flags;
9551
9561
if (is_err(rhs)) return rhs;
···
9557
9567
lhs = resolveprop(js, lhs);
9558
9568
uint8_t lhs_type = vtype(lhs);
9559
9569
if (lhs_type != T_NULL && lhs_type != T_UNDEF) js->flags |= F_NOEXEC;
9570
+
jshdl_t lh = js_root(js, lhs);
9560
9571
jsval_t rhs = js_expr_bp(js, bp);
9572
+
lhs = js_deref(js, lh); js_unroot(js, lh);
9561
9573
if (!(flags & F_NOEXEC) && (lhs_type == T_NULL || lhs_type == T_UNDEF)) lhs = rhs;
9562
9574
js->flags = flags;
9563
9575
if (is_err(rhs)) return rhs;
···
11023
11035
pos4 = js->pos;
11024
11036
11025
11037
while (!(flags & F_NOEXEC)) {
11026
-
js_gc_maybe(js);
11038
+
js_gc_safepoint(js);
11027
11039
js->flags = flags, js->pos = pos1, js->consumed = 1;
11028
11040
if (next(js) != TOK_SEMICOLON) {
11029
11041
v = resolveprop(js, js_expr(js));
···
11132
11144
11133
11145
if (exe) {
11134
11146
while (true) {
11135
-
js_gc_maybe(js);
11147
+
js_gc_safepoint(js);
11136
11148
js->flags = flags;
11137
11149
js->pos = cond_start;
11138
11150
js->consumed = 1;
···
11228
11240
11229
11241
if (exe) {
11230
11242
do {
11231
-
js_gc_maybe(js);
11243
+
js_gc_safepoint(js);
11232
11244
js->pos = body_start;
11233
11245
js->consumed = 1;
11234
11246
js->flags = (flags & ~F_NOEXEC) | F_LOOP;
···
22682
22694
22683
22695
while (next(js) != TOK_EOF && !is_err(res)) {
22684
22696
res = js_stmt(js);
22685
-
if (js->needs_gc && js->eval_depth == 1) {
22686
-
js->needs_gc = false;
22687
-
if (js_gc_compact(js) > 0) js->gc_alloc_since = 0;
22688
-
}
22697
+
if (js->needs_gc && js->eval_depth == 1) js_gc_safepoint(js);
22689
22698
if (js->flags & F_RETURN) break;
22690
22699
}
22691
22700
+5
src/gc.c
+5
src/gc.c
···
573
573
if (!js || js->brk == 0) return 0;
574
574
if (js->brk < 2 * 1024 * 1024) return 0;
575
575
576
+
if (!js->gc_safe) {
577
+
js->needs_gc = true;
578
+
return 0;
579
+
}
580
+
576
581
mco_coro *running = mco_running();
577
582
int in_coroutine = (running != NULL && running->stack_base != NULL);
578
583
+2
-6
src/reactor.c
+2
-6
src/reactor.c
···
45
45
} else free_coroutine(temp);
46
46
}
47
47
48
-
if (js->needs_gc) {
49
-
js->needs_gc = false;
50
-
if (js_gc_compact(js) > 0) js->gc_alloc_since = 0;
51
-
}
52
-
48
+
if (js->needs_gc) js_gc_safepoint(js);
53
49
if (g_poll_hook) g_poll_hook(g_poll_hook_data);
54
50
}
55
51
···
80
76
81
77
if (work & WORK_BLOCKING) uv_run(uv_default_loop(), UV_RUN_NOWAIT);
82
78
else if ((work & WORK_ASYNC) || uv_alive) {
83
-
js_gc_maybe(js);
79
+
js_gc_safepoint(js);
84
80
uv_run(uv_default_loop(), UV_RUN_ONCE);
85
81
} else if (work & WORK_COROUTINES) break;
86
82
}
+1
-1
src/sugar.c
+1
-1
src/sugar.c
+15
tests/test_gc_stress7.js
+15
tests/test_gc_stress7.js
···
1
+
// Minimal crash: pad() + string concat in a nested loop
2
+
function pad(s, n) {
3
+
while (s.length < n) s += ' ';
4
+
return s;
5
+
}
6
+
7
+
let sink = [];
8
+
for (let i = 0; i < 10000; i++) {
9
+
for (let j = 0; j < 5; j++) {
10
+
sink.push(pad('INFO', 5) + ' ' + pad('hello', 15));
11
+
}
12
+
if (sink.length > 100) sink = [];
13
+
}
14
+
15
+
console.log('OK');