Time::HiRes Win32 add nv_gettimeofday() nv_clock_gettime() anti-precsn loss

-add NV retval variants nv_gettimeofday() and
 nv_clock_gettime(clock_id, &status), the splitting of the solo U64,
 into 2 IVs/UVs (64b IVs/UVs on my system), then recombing those 2 integers
 with integer or FP double logic, was very messy and verbose machine code
 and no, MSVC didn't "algebra" const fold away the splitting and recombing
 logic, so just create polyfills that always return NVs from the start
-do "- ((U64)EPOCH_BIAS" with U64 logic, for maximum chance of
 no rounding/no precision loss, then do division with FP logic for maximum
 fractional number precision
-"NV nv = nv_clock_gettime(clock_id, &status);" is inlined away,
 var bool status; has no C stack or register representation in mach code
 with MSVC 2022 -O1. Returning a pass by copy
 struct {NV nv; bool success;}; was considered, but never tried, b/c of
 Win64 AMD64 ABI's "rule" of all retval types > 8 bytes become secret ptrs
 and a secret 1st arg. Maybe MSVC would inline and fold away the struct,
 maybe it would not. I didn't try it. Current impl is working as intended.
-nv_clock_gettime() still needs to reject junk values in clock_id remember
-add tick_frequency_nv, so U64 -> NV is done 1x at startup, not in the
 run loop
-S_croak_xs_unimplemented(const CV *const cv) silence CC warning, cv_name()
 doesn't want a const CV* head struct

Author: bulk88

dist/Time-HiRes/HiRes.xs

@@ -246,6 +246,10 @@ typedef int clockid_t;
 #    define HAS_GETTIMEOFDAY
 #  endif
 
+#  ifndef HAS_NV_GETTIMEOFDAY
+#    define HAS_NV_GETTIMEOFDAY
+#  endif
+
 /* shows up in winsock.h?
 struct timeval {
     long tv_sec;
@@ -270,6 +274,7 @@ typedef struct {
 typedef BOOL (WINAPI *pfnQueryPerformanceCounter_T)(LARGE_INTEGER*);
 
 static unsigned __int64 tick_frequency = 0;
+static NV tick_frequency_nv = 0;
 static unsigned __int64 qpc_res_ns = 0;
 static unsigned __int64 qpc_res_ns_realtime = 0;
 static pfnQueryPerformanceCounter_T pfnQueryPerformanceCounter = NULL;
@@ -331,6 +336,10 @@ START_MY_CXT
 #  undef clock_gettime
 #  define clock_gettime(clock_id, tp) _clock_gettime(aTHX_ clock_id, tp)
 
+#  define TIME_HIRES_NV_CLOCK_GETTIME
+#  undef nv_clock_gettime
+#  define nv_clock_gettime(clock_id, _bp) _nv_clock_gettime(aTHX_ clock_id, _bp)
+
 #  undef clock_getres
 #  define clock_getres(clock_id, tp) _clock_getres(clock_id, tp)
 
@@ -447,6 +456,18 @@ _gettimeofday_x(pTHX)
     return tp;
 }
 
+PERL_STATIC_FORCE_INLINE NV
+nv_gettimeofday_x(pTHX)
+{
+    FT_t ft;
+
+    GetSystemTimePreciseAsFileTime(&ft.ft_val);
+
+    /* FP seconds since epoch */
+    return ((NV)((U64)((U64)ft.ft_i64) - ((U64)EPOCH_BIAS))) / ((NV)NV_1E7);
+}
+#define nv_gettimeofday() nv_gettimeofday_x(aTHX)
+
 /* force inline it, because XS_Time__HiRes_clock_gettime() is the only caller */
 
 PERL_STATIC_FORCE_INLINE int
@@ -477,6 +498,30 @@ _clock_gettime(pTHX_ clockid_t clock_id, struct timespec *tp)
     return 0;
 }
 
+PERL_STATIC_FORCE_INLINE NV
+_nv_clock_gettime(pTHX_ clockid_t clock_id, bool * statusp)
+{
+    FT_t ft;
+    unsigned __int64 ticks;
+    unsigned __int64 time_sys;
+
+    *statusp = 0;
+    switch (clock_id) {
+    case CLOCK_REALTIME:
+        GetSystemTimePreciseAsFileTime(&ft.ft_val);
+        time_sys = ft.ft_i64;
+        return ((NV)((U64)((U64)time_sys) - ((U64)EPOCH_BIAS))) / ((NV)NV_1E7);
+    case CLOCK_MONOTONIC:
+        QueryPerformanceCounter((LARGE_INTEGER*)&ft.ft_i64);
+        ticks = ft.ft_i64;
+        return ((NV)ticks) / tick_frequency_nv;
+    default:
+        *statusp = 1;
+        errno = EINVAL;
+        return -1.0;
+    }
+}
+
 static int
 _clock_getres(clockid_t clock_id, struct timespec *tp)
 {
@@ -807,21 +852,29 @@ myNVtime()
    return myNVtime_cxt(aTHX);
 #    endif
 #  endif
+#ifdef HAS_NV_GETTIMEOFDAY
+    return nv_gettimeofday();
+#else
     struct timeval Tp;
     int status;
     status = gettimeofday (&Tp, NULL);
     return status == 0 ? Tp.tv_sec + (Tp.tv_usec / NV_1E6) : -1.0;
+#endif
 }
 
 #ifdef PERL_IMPLICIT_CONTEXT
 
 static NV
 myNVtime_cxt(pTHX)
 {
+#ifdef HAS_NV_GETTIMEOFDAY
+    return nv_gettimeofday();
+#else
     struct timeval Tp;
     int status;
     status = gettimeofday (&Tp, NULL);
     return status == 0 ? Tp.tv_sec + (Tp.tv_usec / NV_1E6) : -1.0;
+#endif
 }
 
 #endif
@@ -1116,10 +1169,10 @@ nsec_without_unslept(struct timespec *sleepfor,
 #endif
 
 STATIC void
-S_croak_xs_unimplemented(const CV *const cv);
+S_croak_xs_unimplemented(CV *const cv);
 
 STATIC void
-S_croak_xs_unimplemented(const CV *const cv)
+S_croak_xs_unimplemented(CV *const cv)
 {
     dTHX;
     SV* sv = cv_name(cv, NULL, 0);
@@ -1175,6 +1228,7 @@ BOOT:
                 "QueryPerformanceFrequency");
         l_tick_frequency = l_tick_frequency_mem;
              /* 32-bit CPU anti-sharding paranoia */
+        tick_frequency_nv = (NV)l_tick_frequency;
         S_InterlockedExchange64(&tick_frequency, l_tick_frequency);
     }
     l_qpc_res_ns = qpc_res_ns;
@@ -1509,30 +1563,47 @@ alarm(seconds,interval=0)
 
 #ifdef HAS_GETTIMEOFDAY
 
+#ifdef HAS_NV_GETTIMEOFDAY
+#  define HAS_NV_GETTIMEOFDAY_BOOL 1
+#else
+#  define HAS_NV_GETTIMEOFDAY_BOOL 0
+#endif
+
 void
 gettimeofday()
     PREINIT:
         struct timeval Tp;
         int status;
         OP* const op = PL_op;
         U8 is_G_LIST = GIMME_V == G_LIST;
+        NV nv;
+        const U8 do_taint = 1;
     PPCODE:
         if (is_G_LIST)
             EXTEND(sp, 2);
+        else if(HAS_NV_GETTIMEOFDAY_BOOL) {
+#ifdef HAS_NV_GETTIMEOFDAY
+            nv = nv_gettimeofday();
+#endif
+            goto ret_1_nv;
+        }
         status = gettimeofday (&Tp, NULL);
         if (status == 0) {
-            if (is_G_LIST) { /* copy to registers to prove sv_2mortal/newSViv */
+            if (HAS_NV_GETTIMEOFDAY_BOOL || is_G_LIST) {
+                /* copy to registers to prove sv_2mortal/newSViv */
                 IV sec = Tp.tv_sec; /* can't modify the values */
                 IV usec = Tp.tv_usec;
                 PUSHs(sv_2mortal(newSViv(sec)));
                 PUSHs(sv_2mortal(newSViv(usec)));
             } else {
                 /* no Perl_leave_adjust_stacks() hazard here,
                    only a PP vs call_sv() hazard */
-                NV nv = Tp.tv_sec + (Tp.tv_usec / NV_1E6);
-                const U8 do_taint = 1;
-                NV TARGn_nv = nv;
+                NV TARGn_nv;
                 SV* rsv;
+                nv = Tp.tv_sec + (Tp.tv_usec / NV_1E6);
+
+                ret_1_nv:
+                TARGn_nv = nv;
                 if (op->op_private & OPpENTERSUB_HASTARG) {
                     rsv = PAD_SV(op->op_targ);
                     if (LIKELY(
@@ -1559,17 +1630,23 @@ gettimeofday()
 void
 time()
     PREINIT:
-        struct timeval Tp;
         SV* rsv;
         NV RETVAL;
-    CODE:
+#ifndef HAS_NV_GETTIMEOFDAY
+        struct timeval Tp;
         int status;
+#endif
+    CODE:
+#ifndef HAS_NV_GETTIMEOFDAY
         status = gettimeofday (&Tp, NULL);
         if (status == 0) {
             RETVAL = Tp.tv_sec + (Tp.tv_usec / NV_1E6);
         } else {
             RETVAL = -1.0;
         }
+#else
+        RETVAL = nv_gettimeofday();
+#endif
         TMR_TARGn(rsv, RETVAL, 1);
         PUSHs(rsv); /* 0 in, 1 out, entersub guarenteed 1 slot */
         PUTBACK;
@@ -1739,17 +1816,27 @@ void
 clock_gettime(clock_id = CLOCK_REALTIME)
     clockid_t clock_id
     PREINIT:
+#ifndef TIME_HIRES_NV_CLOCK_GETTIME
         struct timespec ts;
         int status;
+#endif
         SV* rsv;
         NV RETVAL;
     PPCODE:
 #  ifdef TIME_HIRES_CLOCK_GETTIME_SYSCALL
         status = syscall(SYS_clock_gettime, clock_id, &ts);
 #  else
+#    ifndef TIME_HIRES_NV_CLOCK_GETTIME
         status = clock_gettime(clock_id, &ts);
-#  endif
         RETVAL = status == 0 ? ts.tv_sec + (NV) ts.tv_nsec / NV_1E9 : -1;
+#    else
+        {
+            bool status;
+            NV nv = nv_clock_gettime(clock_id, &status);
+            RETVAL = status == 0 ? nv : -1;
+        }
+#    endif
+#  endif
         TMR_TARGn(rsv, RETVAL, 1);
         PUSHs(rsv); /* 0 or 1 in, 1 out, PPCODE: did rewind */
         PUTBACK;