Add timestamp to GC log

ocaml/runtime/caml/osdeps.h

@@ -103,6 +103,9 @@ extern char_os *caml_secure_getenv(char_os const *var);
    cannot be determined, return -1. */
 extern int caml_num_rows_fd(int fd);
 
+/* Print a timestamp for verbose GC logs */
+extern void caml_print_timestamp(FILE* channel, int formatted);
+
 /* Memory management platform-specific operations */
 
 void *caml_plat_mem_map(uintnat, uintnat, int);

ocaml/runtime/misc.c

@@ -97,6 +97,9 @@ void caml_gc_message (int level, char *msg, ...)
   if ((atomic_load_relaxed(&caml_verb_gc) & level) != 0){
     va_list ap;
     va_start(ap, msg);
+    if (caml_verb_gc & 0x1000) {
+      caml_print_timestamp(stderr, caml_verb_gc & 0x2000);
+    }
     vfprintf (stderr, msg, ap);
     va_end(ap);
     fflush (stderr);

ocaml/runtime/unix.c

@@ -43,9 +43,8 @@
 #ifdef HAS_UNISTD
 #include <unistd.h>
 #endif
-#ifdef HAS_POSIX_MONOTONIC_CLOCK
 #include <time.h>
-#elif HAS_MACH_ABSOLUTE_TIME
+#ifdef HAS_MACH_ABSOLUTE_TIME
 #include <mach/mach_time.h>
 #endif
 #ifdef HAS_DIRENT
@@ -476,6 +475,35 @@ int caml_num_rows_fd(int fd)
 #endif
 }
 
+void caml_print_timestamp(FILE* channel, int formatted)
+{
+  struct timeval tv;
+  gettimeofday(&tv, NULL);
+  if (!formatted) {
+    fprintf(channel, "%ld.%06d ", (long)tv.tv_sec, (int)tv.tv_usec);
+  } else {
+    struct tm tm;
+    char tz[10] = "Z";
+    localtime_r(&tv.tv_sec, &tm);
+    if (tm.tm_gmtoff != 0) {
+      long tzhour = tm.tm_gmtoff / 60 / 60;
+      long tzmin = (tm.tm_gmtoff / 60) % 60;
+      if (tzmin < 0) {tzmin += 60; tzhour--;}
+      sprintf(tz, "%+03ld:%02ld", tzhour, tzmin);
+    }
+    fprintf(channel,
+            "[%04d-%02d-%02d %02d:%02d:%02d.%06d%s] ",
+            1900 + tm.tm_year,
+            tm.tm_mon + 1,
+            tm.tm_mday,
+            tm.tm_hour,
+            tm.tm_min,
+            tm.tm_sec,
+            (int)tv.tv_usec,
+            tz);
+  }
+}
+
 void caml_init_os_params(void)
 {
   caml_plat_mmap_alignment = caml_plat_pagesize = sysconf(_SC_PAGESIZE);

ocaml/runtime/win32.c

@@ -1107,6 +1107,11 @@ int caml_num_rows_fd(int fd)
   return -1;
 }
 
+void caml_print_timestamp(FILE* channel, int formatted)
+{
+  /* unimplemented */
+}
+
 /* UCRT clock function returns wall-clock time */
 CAMLexport clock_t caml_win32_clock(void)
 {