Move more time functions to native code. NFC (#16439)

I'm pretty this is going to be codesize win for a lot of codebases even though its not showing up in our (minimal) codesize tests.
emscripten-core · Mar 9, 2022 · fa6afb8 · fa6afb8
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commit fa6afb8
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Showing 7 changed files with 113 additions and 99 deletions.
diff --git a/src/library.js b/src/library.js
@@ -391,25 +391,9 @@ LibraryManager.library = {
   // time.h
   // ==========================================================================
 
-  clock__sig: 'i',
-  clock: function() {
-    if (_clock.start === undefined) _clock.start = Date.now();
-    return ((Date.now() - _clock.start) * ({{{ cDefine('CLOCKS_PER_SEC') }}} / 1000))|0;
-  },
-
-  time__sig: 'ii',
-  time: function(ptr) {
-    {{{ from64('ptr') }}};
-    var ret = (Date.now()/1000)|0;
-    if (ptr) {
-      {{{ makeSetValue('ptr', 0, 'ret', 'i32') }}};
-    }
-    return ret;
-  },
-
-  difftime__sig: 'dii',
-  difftime: function(time1, time0) {
-    return time1 - time0;
+  _emscripten_date_now__sig: 'j',
+  _emscripten_date_now: function() {
+    return Date.now();
   },
 
   _mktime_js__sig: 'ii',
@@ -549,11 +533,6 @@ LibraryManager.library = {
     return ret;
   },
 
-  dysize: function(year) {
-    var leap = ((year % 4 == 0) && ((year % 100 != 0) || (year % 400 == 0)));
-    return leap ? 366 : 365;
-  },
-
   // TODO: Initialize these to defaults on startup from system settings.
   // Note: glibc has one fewer underscore for all of these. Also used in other related functions (timegm)
   _tzset_js__deps: ['tzset_impl'],
@@ -1246,66 +1225,6 @@ LibraryManager.library = {
     return _strptime(buf, format, tm); // no locale support yet
   },
 
-  timespec_get__deps: ['clock_gettime', '$setErrNo'],
-  timespec_get: function(ts, base) {
-    //int timespec_get(struct timespec *ts, int base);
-    if (base !== {{{ cDefine('TIME_UTC') }}}) {
-      // There is no other implemented value than TIME_UTC; all other values are considered erroneous.
-      setErrNo({{{ cDefine('EINVAL') }}});
-      return 0;
-    }
-    var ret = _clock_gettime({{{ cDefine('CLOCK_REALTIME') }}}, ts);
-    return ret < 0 ? 0 : base;
-  },
-
-  // ==========================================================================
-  // sys/time.h
-  // ==========================================================================
-
-  clock_gettime__sig: 'iii',
-  clock_gettime__deps: ['emscripten_get_now', 'emscripten_get_now_is_monotonic', '$setErrNo'],
-  clock_gettime: function(clk_id, tp) {
-    // int clock_gettime(clockid_t clk_id, struct timespec *tp);
-    var now;
-    if (clk_id === {{{ cDefine('CLOCK_REALTIME') }}}) {
-      now = Date.now();
-    } else if ((clk_id === {{{ cDefine('CLOCK_MONOTONIC') }}} || clk_id === {{{ cDefine('CLOCK_MONOTONIC_RAW') }}}) && _emscripten_get_now_is_monotonic) {
-      now = _emscripten_get_now();
-    } else {
-      setErrNo({{{ cDefine('EINVAL') }}});
-      return -1;
-    }
-    {{{ makeSetValue('tp', C_STRUCTS.timespec.tv_sec, '(now/1000)|0', 'i32') }}}; // seconds
-    {{{ makeSetValue('tp', C_STRUCTS.timespec.tv_nsec, '((now % 1000)*1000*1000)|0', 'i32') }}}; // nanoseconds
-    return 0;
-  },
-  __clock_gettime__sig: 'iii',
-  __clock_gettime: 'clock_gettime', // musl internal alias
-  clock_getres__deps: ['emscripten_get_now_res', 'emscripten_get_now_is_monotonic', '$setErrNo'],
-  clock_getres: function(clk_id, res) {
-    // int clock_getres(clockid_t clk_id, struct timespec *res);
-    var nsec;
-    if (clk_id === {{{ cDefine('CLOCK_REALTIME') }}}) {
-      nsec = 1000 * 1000; // educated guess that it's milliseconds
-    } else if (clk_id === {{{ cDefine('CLOCK_MONOTONIC') }}} && _emscripten_get_now_is_monotonic) {
-      nsec = _emscripten_get_now_res();
-    } else {
-      setErrNo({{{ cDefine('EINVAL') }}});
-      return -1;
-    }
-    {{{ makeSetValue('res', C_STRUCTS.timespec.tv_sec, '(nsec/1000000000)|0', 'i32') }}};
-    {{{ makeSetValue('res', C_STRUCTS.timespec.tv_nsec, 'nsec', 'i32') }}} // resolution is nanoseconds
-    return 0;
-  },
-  gettimeofday__sig: 'iii',
-  // http://pubs.opengroup.org/onlinepubs/000095399/basedefs/sys/time.h.html
-  gettimeofday: function(ptr) {
-    var now = Date.now();
-    {{{ makeSetValue('ptr', C_STRUCTS.timeval.tv_sec, '(now/1000)|0', 'i32') }}}; // seconds
-    {{{ makeSetValue('ptr', C_STRUCTS.timeval.tv_usec, '((now % 1000)*1000)|0', 'i32') }}}; // microseconds
-    return 0;
-  },
-
   // ==========================================================================
   // sys/timeb.h
   // ==========================================================================
@@ -2463,8 +2382,9 @@ LibraryManager.library = {
 
   // Represents whether emscripten_get_now is guaranteed monotonic; the Date.now
   // implementation is not :(
+  $nowIsMonotonic__internal: true,
 #if MIN_IE_VERSION <= 9 || MIN_FIREFOX_VERSION <= 14 || MIN_CHROME_VERSION <= 23 || MIN_SAFARI_VERSION <= 80400 // https://caniuse.com/#feat=high-resolution-time
-  emscripten_get_now_is_monotonic: `
+  $nowIsMonotonic: `
      ((typeof performance == 'object' && performance && typeof performance['now'] == 'function')
 #if ENVIRONMENT_MAY_BE_NODE
       || ENVIRONMENT_IS_NODE
@@ -2475,9 +2395,15 @@ LibraryManager.library = {
     );`,
 #else
   // Modern environment where performance.now() is supported: (rely on minifier to return true unconditionally from this function)
-  emscripten_get_now_is_monotonic: 'true;',
+  $nowIsMonotonic: 'true;',
 #endif
 
+  _emscripten_get_now_is_monotonic__internal: true,
+  _emscripten_get_now_is_monotonic__deps: ['$nowIsMonotonic'],
+  _emscripten_get_now_is_monotonic: function() {
+    return nowIsMonotonic;
+  },
+
 #if MINIMAL_RUNTIME
   $warnOnce: function(text) {
     if (!warnOnce.shown) warnOnce.shown = {};

diff --git a/src/library_wasi.js b/src/library_wasi.js
@@ -137,7 +137,7 @@ var WasiLibrary = {
   // either wait for BigInt support or to legalize on the client.
   clock_time_get__nothrow: true,
   clock_time_get__sig: 'iiiii',
-  clock_time_get__deps: ['emscripten_get_now', 'emscripten_get_now_is_monotonic', '$checkWasiClock'],
+  clock_time_get__deps: ['emscripten_get_now', '$nowIsMonotonic', '$checkWasiClock'],
   clock_time_get: function(clk_id, {{{ defineI64Param('precision') }}}, ptime) {
     {{{ receiveI64ParamAsI32s('precision') }}}
     if (!checkWasiClock(clk_id)) {
@@ -147,7 +147,7 @@ var WasiLibrary = {
     // all wasi clocks but realtime are monotonic
     if (clk_id === {{{ cDefine('__WASI_CLOCKID_REALTIME') }}}) {
       now = Date.now();
-    } else if (_emscripten_get_now_is_monotonic) {
+    } else if (nowIsMonotonic) {
       now = _emscripten_get_now();
     } else {
       return {{{ cDefine('ENOSYS') }}};
@@ -161,7 +161,7 @@ var WasiLibrary = {
 
   clock_res_get__nothrow: true,
   clock_res_get__sig: 'iii',
-  clock_res_get__deps: ['emscripten_get_now', 'emscripten_get_now_res', 'emscripten_get_now_is_monotonic', '$checkWasiClock'],
+  clock_res_get__deps: ['emscripten_get_now', 'emscripten_get_now_res', '$nowIsMonotonic', '$checkWasiClock'],
   clock_res_get: function(clk_id, pres) {
     if (!checkWasiClock(clk_id)) {
       return {{{ cDefine('EINVAL') }}};
@@ -170,7 +170,7 @@ var WasiLibrary = {
     // all wasi clocks but realtime are monotonic
     if (clk_id === {{{ cDefine('CLOCK_REALTIME') }}}) {
       nsec = 1000 * 1000; // educated guess that it's milliseconds
-    } else if (_emscripten_get_now_is_monotonic) {
+    } else if (nowIsMonotonic) {
       nsec = _emscripten_get_now_res();
     } else {
       return {{{ cDefine('ENOSYS') }}};

diff --git a/src/struct_info.json b/src/struct_info.json
@@ -158,8 +158,6 @@
     {
         "file": "time.h",
         "defines": [
-            ["li", "CLOCKS_PER_SEC"],
-            "TIME_UTC",
             "CLOCK_REALTIME",
             "CLOCK_MONOTONIC",
             "CLOCK_MONOTONIC_RAW"

diff --git a/system/lib/libc/emscripten_time.c b/system/lib/libc/emscripten_time.c
@@ -5,8 +5,11 @@
  * found in the LICENSE file.
  */
 
+#include <emscripten/emscripten.h>
 #include <time.h>
 #include <stdbool.h>
+#include <sys/time.h>
+#include <threads.h>
 #include "libc.h"
 
 // Replaces musl's __tz.c
@@ -20,6 +23,8 @@ time_t _timegm_js(struct tm *tm);
 time_t _mktime_js(struct tm *tm);
 void _localtime_js(const time_t *restrict t, struct tm *restrict tm);
 void _gmtime_js(const time_t *restrict t, struct tm *restrict tm);
+double _emscripten_date_now();
+double emscripten_get_now_res();
 
 __attribute__((__weak__))
 void tzset() {
@@ -57,5 +62,91 @@ struct tm *__gmtime_r(const time_t *restrict t, struct tm *restrict tm) {
   return tm;
 }
 
+__attribute__((__weak__))
+clock_t __clock() {
+  static thread_local double start = 0;
+  if (!start) {
+    start = _emscripten_date_now();
+  }
+  return (_emscripten_date_now() - start) * (CLOCKS_PER_SEC / 1000);
+}
+
+__attribute__((__weak__))
+time_t __time(time_t *t) {
+  double ret = _emscripten_date_now() / 1000;
+  if (t) {
+    *t = ret;
+  }
+  return ret;
+}
+
+extern bool _emscripten_get_now_is_monotonic();
+static thread_local bool checked_monotonic = false;
+static thread_local bool is_monotonic = 0;
+
+__attribute__((__weak__))
+int __clock_gettime(clockid_t clk, struct timespec *ts) {
+  if (!checked_monotonic) {
+    is_monotonic = _emscripten_get_now_is_monotonic();
+    checked_monotonic = true;
+  }
+
+  double now_ms;
+  if (clk == CLOCK_REALTIME) {
+    now_ms = _emscripten_date_now();
+  } else if ((clk == CLOCK_MONOTONIC || clk == CLOCK_MONOTONIC_RAW) && is_monotonic) {
+    now_ms = emscripten_get_now();
+  } else {
+    errno = EINVAL;
+    return -1;
+  }
+
+  long long now_s = now_ms / 1000;
+  ts->tv_sec = now_s; // seconds
+  ts->tv_nsec = (now_ms - (now_s * 1000)) * 1000 * 1000; // nanoseconds
+  return 0;
+}
+
+__attribute__((__weak__))
+int __clock_getres(clockid_t clk, struct timespec *ts) {
+  if (!checked_monotonic) {
+    is_monotonic = _emscripten_get_now_is_monotonic();
+    checked_monotonic = true;
+  }
+
+  double nsec;
+  if (clk == CLOCK_REALTIME) {
+    nsec = 1000 * 1000; // educated guess that it's milliseconds
+  } else if (clk == CLOCK_MONOTONIC && is_monotonic) {
+    nsec = emscripten_get_now_res();
+  } else {
+    errno = EINVAL;
+    return -1;
+  }
+  ts->tv_sec = (nsec / (1000 * 1000 * 1000));
+  ts->tv_nsec = nsec;
+  return 0;
+}
+
+__attribute__((__weak__))
+int __gettimeofday(struct timeval *restrict tv, void *restrict tz) {
+  double now_ms = _emscripten_date_now();
+  long long now_s = now_ms / 1000;
+  tv->tv_sec = now_s; // seconds
+  tv->tv_usec = (now_ms - (now_s * 1000)) * 1000; // nicroseconds
+  return 0;
+}
+
+__attribute__((__weak__))
+int dysize(int year) {
+  int leap = ((year % 4 == 0) && ((year % 100 != 0) || (year % 400 == 0)));
+  return leap ? 366 : 365;
+}
+
 weak_alias(__gmtime_r, gmtime_r);
 weak_alias(__localtime_r, localtime_r);
+weak_alias(__time, time);
+weak_alias(__clock, clock);
+weak_alias(__clock_gettime, clock_gettime);
+weak_alias(__clock_getres, clock_getres);
+weak_alias(__gettimeofday, gettimeofday);
diff --git a/tests/code_size/random_printf_wasm.json b/tests/code_size/random_printf_wasm.json
@@ -1,6 +1,6 @@
 {
-  "a.html": 12955,
-  "a.html.gz": 6995,
-  "total": 12955,
-  "total_gz": 6995
+  "a.html": 12977,
+  "a.html.gz": 6991,
+  "total": 12977,
+  "total_gz": 6991
 }
diff --git a/tests/reference_struct_info.json b/tests/reference_struct_info.json
@@ -17,7 +17,6 @@
         "AUDIO_F32": 33056,
         "AUDIO_S16LSB": 32784,
         "AUDIO_U8": 8,
-        "CLOCKS_PER_SEC": 1000000,
         "CLOCK_MONOTONIC": 1,
         "CLOCK_MONOTONIC_RAW": 4,
         "CLOCK_REALTIME": 0,
@@ -351,7 +350,6 @@
         "TCSETS": 21506,
         "TCSETSF": 21508,
         "TCSETSW": 21507,
-        "TIME_UTC": 1,
         "TIOCGPGRP": 21519,
         "TIOCGWINSZ": 21523,
         "TIOCSPGRP": 21520,

diff --git a/tools/system_libs.py b/tools/system_libs.py
@@ -915,11 +915,13 @@ def get_files(self):
           'asctime_r.c',
           'asctime.c',
           'ctime.c',
+          'difftime.c',
           'gmtime.c',
           'localtime.c',
           'nanosleep.c',
           'clock_nanosleep.c',
           'ctime_r.c',
+          'timespec_get.c',
           'utime.c',
         ])
     libc_files += files_in_path(
@@ -1644,7 +1646,6 @@ def get_files(self):
                    '__year_to_secs.c',
                    'clock.c',
                    'clock_gettime.c',
-                   'difftime.c',
                    'gettimeofday.c',
                    'localtime_r.c',
                    'gmtime_r.c',