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Change support vector to Windows 8+

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Doing this makes binaries tinier, since we don't need to have all the
extra code for supporting a 32-bit address space. It also benefits us
because we're able to use WIN32 futexes, which makes locking simpler.

b69f3d2488 is what officially ended our
Windows 7 support. This change is merely a formalization. You can use
old versions of Cosmo now and forevermore if you need Windows 7 since
our repository is hermetic and vendors all its dependencies.

Won't fix #617
This commit is contained in:
Justine Tunney 2022-09-15 03:49:34 -07:00
parent 6c90f830d9
commit 134ffee519
No known key found for this signature in database
GPG key ID: BE714B4575D6E328
25 changed files with 296 additions and 167 deletions
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89
third_party/nsync/futex.c vendored
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@ -17,14 +17,19 @@
│ PERFORMANCE OF THIS SOFTWARE. │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/calls/struct/timespec.internal.h"
#include "libc/calls/syscall_support-nt.internal.h"
#include "libc/dce.h"
#include "libc/errno.h"
#include "libc/intrin/describeflags.internal.h"
#include "libc/intrin/strace.internal.h"
#include "libc/limits.h"
#include "libc/nt/runtime.h"
#include "libc/nt/synchronization.h"
#include "libc/sysv/consts/futex.h"
#include "libc/thread/thread.h"
#include "third_party/nsync/common.internal.h"
#include "third_party/nsync/futex.internal.h"
#include "third_party/nsync/mu_semaphore.internal.h"
// clang-format off
/* futex() polyfill w/ sched_yield() fallback */
@ -41,8 +46,18 @@ bool FUTEX_TIMEOUT_IS_ABSOLUTE;
__attribute__((__constructor__)) static void nsync_futex_init_ (void) {
int x = 0;
if (!(FUTEX_IS_SUPPORTED = IsLinux() || IsOpenbsd()))
if (NSYNC_FUTEX_WIN32 && IsWindows ()) {
FUTEX_IS_SUPPORTED = true;
FUTEX_WAIT_ = FUTEX_WAIT;
return;
}
if (!(FUTEX_IS_SUPPORTED = IsLinux () || IsOpenbsd ())) {
// we're using sched_yield() so let's
// avoid needless clock_gettime calls
FUTEX_TIMEOUT_IS_ABSOLUTE = true;
return;
}
// In our testing, we found that the monotonic clock on various
// popular systems (such as Linux, and some BSD variants) was no
@ -78,8 +93,30 @@ __attribute__((__constructor__)) static void nsync_futex_init_ (void) {
int nsync_futex_wait_ (int *p, int expect, char pshare, struct timespec *timeout) {
int rc, op;
if (FUTEX_IS_SUPPORTED) {
op = FUTEX_WAIT_;
uint32_t ms;
if (!FUTEX_IS_SUPPORTED) {
nsync_yield_ ();
if (timeout) {
return -EINTR;
} else {
return 0;
}
}
op = FUTEX_WAIT_;
if (NSYNC_FUTEX_WIN32 && IsWindows ()) {
if (timeout) {
ms = _timespec_tomillis (*timeout);
} else {
ms = -1;
}
if (WaitOnAddress (p, &expect, sizeof(int), ms)) {
rc = 0;
} else {
rc = -GetLastError ();
}
} else {
if (pshare == PTHREAD_PROCESS_PRIVATE) {
op |= FUTEX_PRIVATE_FLAG_;
}
@ -88,35 +125,45 @@ int nsync_futex_wait_ (int *p, int expect, char pshare, struct timespec *timeout
// [jart] openbsd does this without setting carry flag
rc = -rc;
}
STRACE("futex(%t, %s, %d, %s) → %s",
p, DescribeFutexOp(op), expect,
DescribeTimespec(0, timeout), DescribeFutexResult(rc));
} else {
nsync_yield_ ();
if (timeout) {
rc = -ETIMEDOUT;
} else {
rc = 0;
}
}
STRACE("futex(%t, %s, %d, %s) → %s",
p, DescribeFutexOp (op), expect,
DescribeTimespec (0, timeout),
DescribeFutexResult (rc));
return rc;
}
int nsync_futex_wake_ (int *p, int count, char pshare) {
int rc, op;
int wake (void *, int, int) asm ("_futex");
if (FUTEX_IS_SUPPORTED) {
op = FUTEX_WAKE;
ASSERT (count == 1 || count == INT_MAX);
if (!FUTEX_IS_SUPPORTED) {
nsync_yield_ ();
return 0;
}
op = FUTEX_WAKE;
if (NSYNC_FUTEX_WIN32 && IsWindows ()) {
if (count == 1) {
WakeByAddressSingle (p);
} else {
WakeByAddressAll (p);
}
rc = 0;
} else {
if (pshare == PTHREAD_PROCESS_PRIVATE) {
op |= FUTEX_PRIVATE_FLAG_;
}
rc = wake (p, op, count);
STRACE("futex(%t, %s, %d) → %s", p,
DescribeFutexOp(op),
count, DescribeFutexResult(rc));
} else {
nsync_yield_ ();
rc = 0;
}
STRACE("futex(%t, %s, %d) → %s", p,
DescribeFutexOp(op),
count, DescribeFutexResult(rc));
return rc;
}