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Collect transient native-emitter garbage on heap growth #1493

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0afe38d
Collect transient emission garbage on heap growth
oxura Oct 11, 2026
5342ce1
Emission samples the heap at every def, and the Bun guard is optional…
nicolas-abril Oct 11, 2026
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3 changes: 3 additions & 0 deletions README.md
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Original file line number Diff line number Diff line change
Expand Up @@ -142,6 +142,9 @@ Hints:

Bend works best on the back-end, on Linux or macOS.

Bun's native code emitter samples heap use every 64 definitions and collects
at 2 GiB, then after each 2 GiB of growth. Live compiler state is not capped.

# Examples

### Syntax == Python + dependent types
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6 changes: 6 additions & 0 deletions bend2/comp.ts
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Expand Up @@ -2788,6 +2788,7 @@ export function compile_book(book: Bend.Book): string {
...names.map((c) => Bend.book_fam(FL.book, c))]);
const facts = () => FL.own.size + FL.hot.size + FL.stat.size;
let was: number;
let pressure = 2 ** 31;
do {
was = facts();
[FL.lend, FL.spun, FL.clos, FL.tabs, FL.lits, FL.consts, FL.brws]
Expand All @@ -2798,6 +2799,11 @@ export function compile_book(book: Bend.Book): string {
for (const [k, tld] of [...done_defs().reverse(),
...done_defs(def_foreign)]) {
memo_gc();
// Collect on heap growth, not the host's total RAM budget.
if (process.memoryUsage().heapUsed > pressure) {
globalThis.Bun?.gc(true);
pressure = process.memoryUsage().heapUsed + 2 ** 31;
}
const [dl, vals] = emit_open(scope_new(), k);
FL.segs.push(dl.seg);
if (def_foreign(tld)) {
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