fix(runtime): share uptime anchor across threads

packages/runtime/src/scr_lib.c

@@ -1103,8 +1103,27 @@ void scr_process_exit(double code) {
  * attribute monotonic stamp — the binary's own start, which is what
  * "the current Node.js process" means for a compiled program). */
 #ifdef _WIN32
+#if defined(SCR_LIB) && defined(SCR_THREAD_INSTANCES)
+/* The uptime anchor belongs to the host PROCESS, not to a library
+ * instance. InitOnce keeps the lazy Windows spelling race-free when
+ * several thread instances ask for the clock concurrently. */
+static INIT_ONCE scr_uptime_once = INIT_ONCE_STATIC_INIT;
+static double scr_uptime_t0_ms;
+static BOOL CALLBACK scr_uptime_anchor_once(PINIT_ONCE once, PVOID param,
+                                             PVOID *ctx) {
+  (void)once;
+  (void)param;
+  (void)ctx;
+  scr_uptime_t0_ms = (double)GetTickCount64();
+  return TRUE;
+}
+static void scr_uptime_anchor_init(void) {
+  InitOnceExecuteOnce(&scr_uptime_once, scr_uptime_anchor_once, NULL, NULL);
+}
+#else
 static SCR_TL double scr_uptime_t0_ms;
 static void scr_uptime_anchor_init(void) { scr_uptime_t0_ms = (double)GetTickCount64(); }
+#endif
 static double scr_uptime_now_ms(void) { return (double)GetTickCount64(); }
 #else
 #include <sys/resource.h>
@@ -1112,7 +1131,11 @@ static double scr_uptime_now_ms(void) { return (double)GetTickCount64(); }
 #ifdef __APPLE__
 #include <mach/mach.h>
 #endif
-static SCR_TL double scr_uptime_t0_ms;
+/* A load-time, process-wide anchor: the constructor runs on only the
+ * initial thread, while thread-instanced archives are entered from worker
+ * threads whose TLS slots would otherwise stay zero. It is immutable once
+ * main starts, so sharing it adds no cross-instance mutable state. */
+static double scr_uptime_t0_ms;
 static double scr_uptime_now_ms(void) {
   struct timespec ts;
   clock_gettime(CLOCK_MONOTONIC, &ts);
@@ -1124,7 +1147,9 @@ __attribute__((constructor)) static void scr_uptime_anchor_init(void) {
 #endif
 
 double scr_process_uptime(void) {
-#ifdef _WIN32
+#if defined(_WIN32) && defined(SCR_LIB) && defined(SCR_THREAD_INSTANCES)
+  scr_uptime_anchor_init();
+#elif defined(_WIN32)
   if (scr_uptime_t0_ms == 0) scr_uptime_anchor_init();
 #endif
   return (scr_uptime_now_ms() - scr_uptime_t0_ms) / 1000.0;
@@ -1134,7 +1159,9 @@ double scr_process_uptime(void) {
  * start (Node's timeOrigin anchor), fractional — the same monotonic
  * clock and anchor as uptime, in Node's performance.now units. */
 double scr_perf_now(void) {
-#ifdef _WIN32
+#if defined(_WIN32) && defined(SCR_LIB) && defined(SCR_THREAD_INSTANCES)
+  scr_uptime_anchor_init();
+#elif defined(_WIN32)
   if (scr_uptime_t0_ms == 0) scr_uptime_anchor_init();
 #endif
   return scr_uptime_now_ms() - scr_uptime_t0_ms;

tests/harness/library-multi.test.ts

@@ -446,11 +446,11 @@ function buildThreadProbe(
   return bin;
 }
 
-const THREADED_EXPECTED = `t0: bump x100 -> 101, calls_seen 100, sums_ok=1, trap fell through 0
+const THREADED_EXPECTED = `t0: bump x100 -> 101, calls_seen 100, sums_ok=1, clocks_ok=1, trap fell through 0
 t0 sink: calls=1 ctx_ok=1 fields=3 code=[SC4014] symbol=[mt_boom] addr_nonzero=1
-t1: bump x150 -> 151, calls_seen 150, sums_ok=1, post_ok=1
-t2: bump x200 -> 201, calls_seen 200, sums_ok=1, post_ok=1
-t3: bump x250 -> 251, calls_seen 250, sums_ok=1, post_ok=1
+t1: bump x150 -> 151, calls_seen 150, sums_ok=1, clocks_ok=1, post_ok=1
+t2: bump x200 -> 201, calls_seen 200, sums_ok=1, clocks_ok=1, post_ok=1
+t3: bump x250 -> 251, calls_seen 250, sums_ok=1, clocks_ok=1, post_ok=1
 survivor sinks: 0 0 0
 `;
 
@@ -510,7 +510,7 @@ localizationTest("M7: thread-instanced and runtime-localized archives compose in
     : [];
   expect([...defined].sort()).toEqual(
     [
-      "mt_boom", "mt_bump", "mt_calls_seen", "mt_collect", "mt_init", "mt_set_panic_sink", "mt_sum_to",
+      "mt_boom", "mt_bump", "mt_calls_seen", "mt_collect", "mt_init", "mt_perf_now", "mt_set_panic_sink", "mt_sum_to", "mt_uptime",
       ...toolchainDefinitions,
     ].sort(),
   );

tests/library-mode/thread-instances/lib.ts

@@ -4,6 +4,8 @@
 // (array index OOB — the runtime's own range trap) that must reach only the
 // calling thread's sink. No top-level output: four instances init
 // concurrently in the probe.
+import { performance } from "node:perf_hooks";
+
 let calls = 0;
 
 export function bump(x: number): number {
@@ -27,3 +29,11 @@ export function boom(i: number): number {
   const xs = [1, 2, 3];
   return xs[i]!;
 }
+
+export function uptime(): number {
+  return process.uptime();
+}
+
+export function perfNow(): number {
+  return performance.now();
+}

tests/library-mode/thread-instances/probe.c

@@ -23,6 +23,8 @@ extern double mt_bump(double x);
 extern double mt_calls_seen(void);
 extern double mt_sum_to(double n);
 extern double mt_boom(double i);
+extern double mt_uptime(void);
+extern double mt_perf_now(void);
 
 #define NTHREADS 4
 
@@ -80,6 +82,7 @@ typedef struct {
   double last_bump;
   double calls_seen;
   int sums_ok;
+  int clocks_ok;
   int trap_fell_through; /* thread 0 only */
   int post_ok;           /* threads 1..3 only */
 } Worker;
@@ -121,6 +124,9 @@ static void *worker(void *arg) {
   Worker *w = arg;
   mt_set_panic_sink(sink, &w->sink);
   mt_init(); /* concurrent across all four threads: each init is instance-local */
+  double uptime = mt_uptime();
+  double perf_now = mt_perf_now();
+  w->clocks_ok = uptime >= 0 && uptime < 60 && perf_now >= 0 && perf_now < 60000;
   w->sums_ok = 1;
   double last = 0;
   for (int i = 0; i < w->iters; i++) {
@@ -163,7 +169,7 @@ int main(void) {
   for (int i = 0; i < NTHREADS; i++) pthread_join(threads[i], NULL);
   for (int i = 0; i < NTHREADS; i++) {
     Worker *w = &workers[i];
-    printf("t%d: bump x%d -> %.0f, calls_seen %.0f, sums_ok=%d", i, w->iters, w->last_bump, w->calls_seen, w->sums_ok);
+    printf("t%d: bump x%d -> %.0f, calls_seen %.0f, sums_ok=%d, clocks_ok=%d", i, w->iters, w->last_bump, w->calls_seen, w->sums_ok, w->clocks_ok);
     if (i == 0) {
       printf(", trap fell through %d\n", w->trap_fell_through);
       printf("t0 sink: calls=%d ctx_ok=%d fields=%d code=[%s] symbol=[%s] addr_nonzero=%d\n",

tests/library-mode/thread-instances/profile_t.json

@@ -16,6 +16,8 @@
     { "export": "bump", "symbol": "mt_bump", "params": ["f64"], "returns": "f64" },
     { "export": "callsSeen", "symbol": "mt_calls_seen", "params": [], "returns": "f64" },
     { "export": "sumTo", "symbol": "mt_sum_to", "params": ["f64"], "returns": "f64" },
-    { "export": "boom", "symbol": "mt_boom", "params": ["f64"], "returns": "f64" }
+    { "export": "boom", "symbol": "mt_boom", "params": ["f64"], "returns": "f64" },
+    { "export": "uptime", "symbol": "mt_uptime", "params": [], "returns": "f64" },
+    { "export": "perfNow", "symbol": "mt_perf_now", "params": [], "returns": "f64" }
   ]
 }