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win, util: rearrange uv_hrtime

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Rearrange math operations in uv_hrtime. This is a workaround for a
probable compiler bug in VS2019.

Fixes: https://github.com/libuv/libuv/issues/1633

PR-URL: https://github.com/libuv/libuv/pull/2866
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
This commit is contained in:
Bartosz Sosnowski 2020-05-25 15:20:55 +02:00
parent 0356c65f04
commit 7967448696
2 changed files with 13 additions and 13 deletions
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2
src/win/internal.h
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@ -266,7 +266,7 @@ void uv__fs_poll_endgame(uv_loop_t* loop, uv_fs_poll_t* handle);
*/
void uv__util_init(void);
uint64_t uv__hrtime(double scale);
uint64_t uv__hrtime(unsigned int scale);
__declspec(noreturn) void uv_fatal_error(const int errorno, const char* syscall);
int uv__getpwuid_r(uv_passwd_t* pwd);
int uv__convert_utf16_to_utf8(const WCHAR* utf16, int utf16len, char** utf8);

24
src/win/util.c
View File

@ -67,8 +67,8 @@ extern BOOLEAN NTAPI SystemFunction036(PVOID Buffer, ULONG BufferLength);
static char *process_title;
static CRITICAL_SECTION process_title_lock;
/* Interval (in seconds) of the high-resolution clock. */
static double hrtime_interval_ = 0;
/* Frequency of the high-resolution clock. */
static uint64_t hrtime_frequency_ = 0;
/*
@ -84,9 +84,9 @@ void uv__util_init(void) {
* and precompute its reciprocal.
*/
if (QueryPerformanceFrequency(&perf_frequency)) {
hrtime_interval_ = 1.0 / perf_frequency.QuadPart;
hrtime_frequency_ = perf_frequency.QuadPart;
} else {
hrtime_interval_= 0;
uv_fatal_error(GetLastError(), "QueryPerformanceFrequency");
}
}
@ -490,23 +490,23 @@ uint64_t uv_hrtime(void) {
return uv__hrtime(UV__NANOSEC);
}
uint64_t uv__hrtime(double scale) {
uint64_t uv__hrtime(unsigned int scale) {
LARGE_INTEGER counter;
/* If the performance interval is zero, there's no support. */
if (hrtime_interval_ == 0) {
return 0;
}
assert(hrtime_frequency_ != 0);
assert(scale != 0);
if (!QueryPerformanceCounter(&counter)) {
return 0;
uv_fatal_error(GetLastError(), "QueryPerformanceCounter");
}
assert(counter.QuadPart != 0);
/* Because we have no guarantee about the order of magnitude of the
* performance counter interval, integer math could cause this computation
* to overflow. Therefore we resort to floating point math.
*/
return (uint64_t) ((double) counter.QuadPart * hrtime_interval_ * scale);
double scaled_freq = (double)hrtime_frequency_ / scale;
double result = (double) counter.QuadPart / scaled_freq;
return (uint64_t) result;
}