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Rewrite set_date_fields to match the ECMA specification

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- use `double` arithmetic where necessary to match the spec
- use `volatile` to ensure correct order of evaluation
  and prevent FMA code generation
- reject some border cases.
- avoid undefined behavior in `double` -> `int64_t` conversions
- improved tests/test_builtin.js `assert` function to compare
  values more reliably.
- added some tests in `test_date()`
- disable some of these tests on win32 and cygwin targets
This commit is contained in:
Charlie Gordon
2024-02-21 21:22:10 +01:00
parent b91a2aec67
commit b70e764427
3 changed files with 142 additions and 49 deletions
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76
quickjs.c
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@@ -49452,39 +49452,63 @@ static double time_clip(double t) {
return NAN;
}
/* The spec mandates the use of 'double' and it fixes the order
/* The spec mandates the use of 'double' and it specifies the order
of the operations */
static double set_date_fields(double fields[], int is_local) {
int64_t y;
double days, h, m1;
volatile double d; /* enforce evaluation order */
int i, m, md;
double y, m, dt, ym, mn, day, h, s, milli, time, tv;
int yi, mi, i;
int64_t days;
volatile double temp; /* enforce evaluation order */
m1 = fields[1];
m = fmod(m1, 12);
if (m < 0)
m += 12;
y = (int64_t)(fields[0] + floor(m1 / 12));
days = days_from_year(y);
/* emulate 21.4.1.15 MakeDay ( year, month, date ) */
y = fields[0];
m = fields[1];
dt = fields[2];
ym = y + floor(m / 12);
mn = fmod(m, 12);
if (mn < 0)
mn += 12;
if (ym < -271821 || ym > 275760)
return NAN;
for(i = 0; i < m; i++) {
md = month_days[i];
yi = ym;
mi = mn;
days = days_from_year(yi);
for(i = 0; i < mi; i++) {
days += month_days[i];
if (i == 1)
md += days_in_year(y) - 365;
days += md;
days += days_in_year(yi) - 365;
}
days += fields[2] - 1;
/* made d volatile to ensure order of evaluation as specified in ECMA.
* this fixes a test262 error on
* test262/test/built-ins/Date/UTC/fp-evaluation-order.js
day = days + dt - 1;
/* emulate 21.4.1.14 MakeTime ( hour, min, sec, ms ) */
h = fields[3];
m = fields[4];
s = fields[5];
milli = fields[6];
/* Use a volatile intermediary variable to ensure order of evaluation
* as specified in ECMA. This fixes a test262 error on
* test262/test/built-ins/Date/UTC/fp-evaluation-order.js.
* Without the volatile qualifier, the compile can generate code
* that performs the computation in a different order or with instructions
* that produce a different result such as FMA (float multiply and add).
*/
h = fields[3] * 3600000 + fields[4] * 60000 +
fields[5] * 1000 + fields[6];
d = days * 86400000;
d = d + h;
if (is_local)
d += getTimezoneOffset(d) * 60000;
return time_clip(d);
time = h * 3600000;
time += (temp = m * 60000);
time += (temp = s * 1000);
time += milli;
/* emulate 21.4.1.16 MakeDate ( day, time ) */
tv = (temp = day * 86400000) + time; /* prevent generation of FMA */
if (!isfinite(tv))
return NAN;
/* adjust for local time and clip */
if (is_local) {
int64_t ti = tv < INT64_MIN ? INT64_MIN : tv >= 0x1p63 ? INT64_MAX : (int64_t)tv;
tv += getTimezoneOffset(ti) * 60000;
}
return time_clip(tv);
}
static JSValue get_date_field(JSContext *ctx, JSValueConst this_val,