mirror of
https://github.com/autc04/Retro68.git
synced 2024-09-08 05:54:40 +00:00
652 lines
15 KiB
Go
652 lines
15 KiB
Go
|
// Copyright 2009 The Go Authors. All rights reserved.
|
||
|
// Use of this source code is governed by a BSD-style
|
||
|
// license that can be found in the LICENSE file.
|
||
|
|
||
|
package runtime
|
||
|
|
||
|
// This file contains the implementation of Go select statements.
|
||
|
|
||
|
import "unsafe"
|
||
|
|
||
|
const (
|
||
|
debugSelect = false
|
||
|
)
|
||
|
|
||
|
var (
|
||
|
chansendpc = funcPC(chansend)
|
||
|
chanrecvpc = funcPC(chanrecv)
|
||
|
)
|
||
|
|
||
|
func selectsize(size uintptr) uintptr {
|
||
|
selsize := unsafe.Sizeof(_select{}) +
|
||
|
(size-1)*unsafe.Sizeof(_select{}.scase[0]) +
|
||
|
size*unsafe.Sizeof(*_select{}.lockorder) +
|
||
|
size*unsafe.Sizeof(*_select{}.pollorder)
|
||
|
return round(selsize, _Int64Align)
|
||
|
}
|
||
|
|
||
|
func newselect(sel *_select, selsize int64, size int32) {
|
||
|
if selsize != int64(selectsize(uintptr(size))) {
|
||
|
print("runtime: bad select size ", selsize, ", want ", selectsize(uintptr(size)), "\n")
|
||
|
gothrow("bad select size")
|
||
|
}
|
||
|
sel.tcase = uint16(size)
|
||
|
sel.ncase = 0
|
||
|
sel.lockorder = (**hchan)(add(unsafe.Pointer(&sel.scase), uintptr(size)*unsafe.Sizeof(_select{}.scase[0])))
|
||
|
sel.pollorder = (*uint16)(add(unsafe.Pointer(sel.lockorder), uintptr(size)*unsafe.Sizeof(*_select{}.lockorder)))
|
||
|
|
||
|
if debugSelect {
|
||
|
print("newselect s=", sel, " size=", size, "\n")
|
||
|
}
|
||
|
}
|
||
|
|
||
|
//go:nosplit
|
||
|
func selectsend(sel *_select, c *hchan, elem unsafe.Pointer) (selected bool) {
|
||
|
// nil cases do not compete
|
||
|
if c != nil {
|
||
|
selectsendImpl(sel, c, getcallerpc(unsafe.Pointer(&sel)), elem, uintptr(unsafe.Pointer(&selected))-uintptr(unsafe.Pointer(&sel)))
|
||
|
}
|
||
|
return
|
||
|
}
|
||
|
|
||
|
// cut in half to give stack a chance to split
|
||
|
func selectsendImpl(sel *_select, c *hchan, pc uintptr, elem unsafe.Pointer, so uintptr) {
|
||
|
i := sel.ncase
|
||
|
if i >= sel.tcase {
|
||
|
gothrow("selectsend: too many cases")
|
||
|
}
|
||
|
sel.ncase = i + 1
|
||
|
cas := (*scase)(add(unsafe.Pointer(&sel.scase), uintptr(i)*unsafe.Sizeof(sel.scase[0])))
|
||
|
|
||
|
cas.pc = pc
|
||
|
cas._chan = c
|
||
|
cas.so = uint16(so)
|
||
|
cas.kind = _CaseSend
|
||
|
cas.elem = elem
|
||
|
|
||
|
if debugSelect {
|
||
|
print("selectsend s=", sel, " pc=", hex(cas.pc), " chan=", cas._chan, " so=", cas.so, "\n")
|
||
|
}
|
||
|
}
|
||
|
|
||
|
//go:nosplit
|
||
|
func selectrecv(sel *_select, c *hchan, elem unsafe.Pointer) (selected bool) {
|
||
|
// nil cases do not compete
|
||
|
if c != nil {
|
||
|
selectrecvImpl(sel, c, getcallerpc(unsafe.Pointer(&sel)), elem, nil, uintptr(unsafe.Pointer(&selected))-uintptr(unsafe.Pointer(&sel)))
|
||
|
}
|
||
|
return
|
||
|
}
|
||
|
|
||
|
//go:nosplit
|
||
|
func selectrecv2(sel *_select, c *hchan, elem unsafe.Pointer, received *bool) (selected bool) {
|
||
|
// nil cases do not compete
|
||
|
if c != nil {
|
||
|
selectrecvImpl(sel, c, getcallerpc(unsafe.Pointer(&sel)), elem, received, uintptr(unsafe.Pointer(&selected))-uintptr(unsafe.Pointer(&sel)))
|
||
|
}
|
||
|
return
|
||
|
}
|
||
|
|
||
|
func selectrecvImpl(sel *_select, c *hchan, pc uintptr, elem unsafe.Pointer, received *bool, so uintptr) {
|
||
|
i := sel.ncase
|
||
|
if i >= sel.tcase {
|
||
|
gothrow("selectrecv: too many cases")
|
||
|
}
|
||
|
sel.ncase = i + 1
|
||
|
cas := (*scase)(add(unsafe.Pointer(&sel.scase), uintptr(i)*unsafe.Sizeof(sel.scase[0])))
|
||
|
cas.pc = pc
|
||
|
cas._chan = c
|
||
|
cas.so = uint16(so)
|
||
|
cas.kind = _CaseRecv
|
||
|
cas.elem = elem
|
||
|
cas.receivedp = received
|
||
|
|
||
|
if debugSelect {
|
||
|
print("selectrecv s=", sel, " pc=", hex(cas.pc), " chan=", cas._chan, " so=", cas.so, "\n")
|
||
|
}
|
||
|
}
|
||
|
|
||
|
//go:nosplit
|
||
|
func selectdefault(sel *_select) (selected bool) {
|
||
|
selectdefaultImpl(sel, getcallerpc(unsafe.Pointer(&sel)), uintptr(unsafe.Pointer(&selected))-uintptr(unsafe.Pointer(&sel)))
|
||
|
return
|
||
|
}
|
||
|
|
||
|
func selectdefaultImpl(sel *_select, callerpc uintptr, so uintptr) {
|
||
|
i := sel.ncase
|
||
|
if i >= sel.tcase {
|
||
|
gothrow("selectdefault: too many cases")
|
||
|
}
|
||
|
sel.ncase = i + 1
|
||
|
cas := (*scase)(add(unsafe.Pointer(&sel.scase), uintptr(i)*unsafe.Sizeof(sel.scase[0])))
|
||
|
cas.pc = callerpc
|
||
|
cas._chan = nil
|
||
|
cas.so = uint16(so)
|
||
|
cas.kind = _CaseDefault
|
||
|
|
||
|
if debugSelect {
|
||
|
print("selectdefault s=", sel, " pc=", hex(cas.pc), " so=", cas.so, "\n")
|
||
|
}
|
||
|
}
|
||
|
|
||
|
func sellock(sel *_select) {
|
||
|
lockslice := sliceStruct{unsafe.Pointer(sel.lockorder), int(sel.ncase), int(sel.ncase)}
|
||
|
lockorder := *(*[]*hchan)(unsafe.Pointer(&lockslice))
|
||
|
var c *hchan
|
||
|
for _, c0 := range lockorder {
|
||
|
if c0 != nil && c0 != c {
|
||
|
c = c0
|
||
|
lock(&c.lock)
|
||
|
}
|
||
|
}
|
||
|
}
|
||
|
|
||
|
func selunlock(sel *_select) {
|
||
|
// We must be very careful here to not touch sel after we have unlocked
|
||
|
// the last lock, because sel can be freed right after the last unlock.
|
||
|
// Consider the following situation.
|
||
|
// First M calls runtime·park() in runtime·selectgo() passing the sel.
|
||
|
// Once runtime·park() has unlocked the last lock, another M makes
|
||
|
// the G that calls select runnable again and schedules it for execution.
|
||
|
// When the G runs on another M, it locks all the locks and frees sel.
|
||
|
// Now if the first M touches sel, it will access freed memory.
|
||
|
n := int(sel.ncase)
|
||
|
r := 0
|
||
|
lockslice := sliceStruct{unsafe.Pointer(sel.lockorder), n, n}
|
||
|
lockorder := *(*[]*hchan)(unsafe.Pointer(&lockslice))
|
||
|
// skip the default case
|
||
|
if n > 0 && lockorder[0] == nil {
|
||
|
r = 1
|
||
|
}
|
||
|
for i := n - 1; i >= r; i-- {
|
||
|
c := lockorder[i]
|
||
|
if i > 0 && c == lockorder[i-1] {
|
||
|
continue // will unlock it on the next iteration
|
||
|
}
|
||
|
unlock(&c.lock)
|
||
|
}
|
||
|
}
|
||
|
|
||
|
func selparkcommit(gp *g, sel *_select) bool {
|
||
|
selunlock(sel)
|
||
|
return true
|
||
|
}
|
||
|
|
||
|
func block() {
|
||
|
gopark(nil, nil, "select (no cases)") // forever
|
||
|
}
|
||
|
|
||
|
// overwrites return pc on stack to signal which case of the select
|
||
|
// to run, so cannot appear at the top of a split stack.
|
||
|
//go:nosplit
|
||
|
func selectgo(sel *_select) {
|
||
|
pc, offset := selectgoImpl(sel)
|
||
|
*(*bool)(add(unsafe.Pointer(&sel), uintptr(offset))) = true
|
||
|
setcallerpc(unsafe.Pointer(&sel), pc)
|
||
|
}
|
||
|
|
||
|
// selectgoImpl returns scase.pc and scase.so for the select
|
||
|
// case which fired.
|
||
|
func selectgoImpl(sel *_select) (uintptr, uint16) {
|
||
|
if debugSelect {
|
||
|
print("select: sel=", sel, "\n")
|
||
|
}
|
||
|
|
||
|
scaseslice := sliceStruct{unsafe.Pointer(&sel.scase), int(sel.ncase), int(sel.ncase)}
|
||
|
scases := *(*[]scase)(unsafe.Pointer(&scaseslice))
|
||
|
|
||
|
var t0 int64
|
||
|
if blockprofilerate > 0 {
|
||
|
t0 = cputicks()
|
||
|
for i := 0; i < int(sel.ncase); i++ {
|
||
|
scases[i].releasetime = -1
|
||
|
}
|
||
|
}
|
||
|
|
||
|
// The compiler rewrites selects that statically have
|
||
|
// only 0 or 1 cases plus default into simpler constructs.
|
||
|
// The only way we can end up with such small sel.ncase
|
||
|
// values here is for a larger select in which most channels
|
||
|
// have been nilled out. The general code handles those
|
||
|
// cases correctly, and they are rare enough not to bother
|
||
|
// optimizing (and needing to test).
|
||
|
|
||
|
// generate permuted order
|
||
|
pollslice := sliceStruct{unsafe.Pointer(sel.pollorder), int(sel.ncase), int(sel.ncase)}
|
||
|
pollorder := *(*[]uint16)(unsafe.Pointer(&pollslice))
|
||
|
for i := 0; i < int(sel.ncase); i++ {
|
||
|
pollorder[i] = uint16(i)
|
||
|
}
|
||
|
for i := 1; i < int(sel.ncase); i++ {
|
||
|
o := pollorder[i]
|
||
|
j := int(fastrand1()) % (i + 1)
|
||
|
pollorder[i] = pollorder[j]
|
||
|
pollorder[j] = o
|
||
|
}
|
||
|
|
||
|
// sort the cases by Hchan address to get the locking order.
|
||
|
// simple heap sort, to guarantee n log n time and constant stack footprint.
|
||
|
lockslice := sliceStruct{unsafe.Pointer(sel.lockorder), int(sel.ncase), int(sel.ncase)}
|
||
|
lockorder := *(*[]*hchan)(unsafe.Pointer(&lockslice))
|
||
|
for i := 0; i < int(sel.ncase); i++ {
|
||
|
j := i
|
||
|
c := scases[j]._chan
|
||
|
for j > 0 && lockorder[(j-1)/2].sortkey() < c.sortkey() {
|
||
|
k := (j - 1) / 2
|
||
|
lockorder[j] = lockorder[k]
|
||
|
j = k
|
||
|
}
|
||
|
lockorder[j] = c
|
||
|
}
|
||
|
for i := int(sel.ncase) - 1; i >= 0; i-- {
|
||
|
c := lockorder[i]
|
||
|
lockorder[i] = lockorder[0]
|
||
|
j := 0
|
||
|
for {
|
||
|
k := j*2 + 1
|
||
|
if k >= i {
|
||
|
break
|
||
|
}
|
||
|
if k+1 < i && lockorder[k].sortkey() < lockorder[k+1].sortkey() {
|
||
|
k++
|
||
|
}
|
||
|
if c.sortkey() < lockorder[k].sortkey() {
|
||
|
lockorder[j] = lockorder[k]
|
||
|
j = k
|
||
|
continue
|
||
|
}
|
||
|
break
|
||
|
}
|
||
|
lockorder[j] = c
|
||
|
}
|
||
|
/*
|
||
|
for i := 0; i+1 < int(sel.ncase); i++ {
|
||
|
if lockorder[i].sortkey() > lockorder[i+1].sortkey() {
|
||
|
print("i=", i, " x=", lockorder[i], " y=", lockorder[i+1], "\n")
|
||
|
gothrow("select: broken sort")
|
||
|
}
|
||
|
}
|
||
|
*/
|
||
|
|
||
|
// lock all the channels involved in the select
|
||
|
sellock(sel)
|
||
|
|
||
|
var (
|
||
|
gp *g
|
||
|
done uint32
|
||
|
sg *sudog
|
||
|
c *hchan
|
||
|
k *scase
|
||
|
sglist *sudog
|
||
|
sgnext *sudog
|
||
|
)
|
||
|
|
||
|
loop:
|
||
|
// pass 1 - look for something already waiting
|
||
|
var dfl *scase
|
||
|
var cas *scase
|
||
|
for i := 0; i < int(sel.ncase); i++ {
|
||
|
cas = &scases[pollorder[i]]
|
||
|
c = cas._chan
|
||
|
|
||
|
switch cas.kind {
|
||
|
case _CaseRecv:
|
||
|
if c.dataqsiz > 0 {
|
||
|
if c.qcount > 0 {
|
||
|
goto asyncrecv
|
||
|
}
|
||
|
} else {
|
||
|
sg = c.sendq.dequeue()
|
||
|
if sg != nil {
|
||
|
goto syncrecv
|
||
|
}
|
||
|
}
|
||
|
if c.closed != 0 {
|
||
|
goto rclose
|
||
|
}
|
||
|
|
||
|
case _CaseSend:
|
||
|
if raceenabled {
|
||
|
racereadpc(unsafe.Pointer(c), cas.pc, chansendpc)
|
||
|
}
|
||
|
if c.closed != 0 {
|
||
|
goto sclose
|
||
|
}
|
||
|
if c.dataqsiz > 0 {
|
||
|
if c.qcount < c.dataqsiz {
|
||
|
goto asyncsend
|
||
|
}
|
||
|
} else {
|
||
|
sg = c.recvq.dequeue()
|
||
|
if sg != nil {
|
||
|
goto syncsend
|
||
|
}
|
||
|
}
|
||
|
|
||
|
case _CaseDefault:
|
||
|
dfl = cas
|
||
|
}
|
||
|
}
|
||
|
|
||
|
if dfl != nil {
|
||
|
selunlock(sel)
|
||
|
cas = dfl
|
||
|
goto retc
|
||
|
}
|
||
|
|
||
|
// pass 2 - enqueue on all chans
|
||
|
gp = getg()
|
||
|
done = 0
|
||
|
for i := 0; i < int(sel.ncase); i++ {
|
||
|
cas = &scases[pollorder[i]]
|
||
|
c = cas._chan
|
||
|
sg := acquireSudog()
|
||
|
sg.g = gp
|
||
|
// Note: selectdone is adjusted for stack copies in stack.c:adjustsudogs
|
||
|
sg.selectdone = (*uint32)(noescape(unsafe.Pointer(&done)))
|
||
|
sg.elem = cas.elem
|
||
|
sg.releasetime = 0
|
||
|
if t0 != 0 {
|
||
|
sg.releasetime = -1
|
||
|
}
|
||
|
sg.waitlink = gp.waiting
|
||
|
gp.waiting = sg
|
||
|
|
||
|
switch cas.kind {
|
||
|
case _CaseRecv:
|
||
|
c.recvq.enqueue(sg)
|
||
|
|
||
|
case _CaseSend:
|
||
|
c.sendq.enqueue(sg)
|
||
|
}
|
||
|
}
|
||
|
|
||
|
// wait for someone to wake us up
|
||
|
gp.param = nil
|
||
|
gopark(unsafe.Pointer(funcPC(selparkcommit)), unsafe.Pointer(sel), "select")
|
||
|
|
||
|
// someone woke us up
|
||
|
sellock(sel)
|
||
|
sg = (*sudog)(gp.param)
|
||
|
gp.param = nil
|
||
|
|
||
|
// pass 3 - dequeue from unsuccessful chans
|
||
|
// otherwise they stack up on quiet channels
|
||
|
// record the successful case, if any.
|
||
|
// We singly-linked up the SudoGs in case order, so when
|
||
|
// iterating through the linked list they are in reverse order.
|
||
|
cas = nil
|
||
|
sglist = gp.waiting
|
||
|
// Clear all selectdone and elem before unlinking from gp.waiting.
|
||
|
// They must be cleared before being put back into the sudog cache.
|
||
|
// Clear before unlinking, because if a stack copy happens after the unlink,
|
||
|
// they will not be updated, they will be left pointing to the old stack,
|
||
|
// which creates dangling pointers, which may be detected by the
|
||
|
// garbage collector.
|
||
|
for sg1 := gp.waiting; sg1 != nil; sg1 = sg1.waitlink {
|
||
|
sg1.selectdone = nil
|
||
|
sg1.elem = nil
|
||
|
}
|
||
|
gp.waiting = nil
|
||
|
for i := int(sel.ncase) - 1; i >= 0; i-- {
|
||
|
k = &scases[pollorder[i]]
|
||
|
if sglist.releasetime > 0 {
|
||
|
k.releasetime = sglist.releasetime
|
||
|
}
|
||
|
if sg == sglist {
|
||
|
cas = k
|
||
|
} else {
|
||
|
c = k._chan
|
||
|
if k.kind == _CaseSend {
|
||
|
c.sendq.dequeueSudoG(sglist)
|
||
|
} else {
|
||
|
c.recvq.dequeueSudoG(sglist)
|
||
|
}
|
||
|
}
|
||
|
sgnext = sglist.waitlink
|
||
|
sglist.waitlink = nil
|
||
|
releaseSudog(sglist)
|
||
|
sglist = sgnext
|
||
|
}
|
||
|
|
||
|
if cas == nil {
|
||
|
goto loop
|
||
|
}
|
||
|
|
||
|
c = cas._chan
|
||
|
|
||
|
if c.dataqsiz > 0 {
|
||
|
gothrow("selectgo: shouldn't happen")
|
||
|
}
|
||
|
|
||
|
if debugSelect {
|
||
|
print("wait-return: sel=", sel, " c=", c, " cas=", cas, " kind=", cas.kind, "\n")
|
||
|
}
|
||
|
|
||
|
if cas.kind == _CaseRecv {
|
||
|
if cas.receivedp != nil {
|
||
|
*cas.receivedp = true
|
||
|
}
|
||
|
}
|
||
|
|
||
|
if raceenabled {
|
||
|
if cas.kind == _CaseRecv && cas.elem != nil {
|
||
|
raceWriteObjectPC(c.elemtype, cas.elem, cas.pc, chanrecvpc)
|
||
|
} else if cas.kind == _CaseSend {
|
||
|
raceReadObjectPC(c.elemtype, cas.elem, cas.pc, chansendpc)
|
||
|
}
|
||
|
}
|
||
|
|
||
|
selunlock(sel)
|
||
|
goto retc
|
||
|
|
||
|
asyncrecv:
|
||
|
// can receive from buffer
|
||
|
if raceenabled {
|
||
|
if cas.elem != nil {
|
||
|
raceWriteObjectPC(c.elemtype, cas.elem, cas.pc, chanrecvpc)
|
||
|
}
|
||
|
raceacquire(chanbuf(c, c.recvx))
|
||
|
racerelease(chanbuf(c, c.recvx))
|
||
|
}
|
||
|
if cas.receivedp != nil {
|
||
|
*cas.receivedp = true
|
||
|
}
|
||
|
if cas.elem != nil {
|
||
|
memmove(cas.elem, chanbuf(c, c.recvx), uintptr(c.elemsize))
|
||
|
}
|
||
|
memclr(chanbuf(c, c.recvx), uintptr(c.elemsize))
|
||
|
c.recvx++
|
||
|
if c.recvx == c.dataqsiz {
|
||
|
c.recvx = 0
|
||
|
}
|
||
|
c.qcount--
|
||
|
sg = c.sendq.dequeue()
|
||
|
if sg != nil {
|
||
|
gp = sg.g
|
||
|
selunlock(sel)
|
||
|
if sg.releasetime != 0 {
|
||
|
sg.releasetime = cputicks()
|
||
|
}
|
||
|
goready(gp)
|
||
|
} else {
|
||
|
selunlock(sel)
|
||
|
}
|
||
|
goto retc
|
||
|
|
||
|
asyncsend:
|
||
|
// can send to buffer
|
||
|
if raceenabled {
|
||
|
raceacquire(chanbuf(c, c.sendx))
|
||
|
racerelease(chanbuf(c, c.sendx))
|
||
|
raceReadObjectPC(c.elemtype, cas.elem, cas.pc, chansendpc)
|
||
|
}
|
||
|
memmove(chanbuf(c, c.sendx), cas.elem, uintptr(c.elemsize))
|
||
|
c.sendx++
|
||
|
if c.sendx == c.dataqsiz {
|
||
|
c.sendx = 0
|
||
|
}
|
||
|
c.qcount++
|
||
|
sg = c.recvq.dequeue()
|
||
|
if sg != nil {
|
||
|
gp = sg.g
|
||
|
selunlock(sel)
|
||
|
if sg.releasetime != 0 {
|
||
|
sg.releasetime = cputicks()
|
||
|
}
|
||
|
goready(gp)
|
||
|
} else {
|
||
|
selunlock(sel)
|
||
|
}
|
||
|
goto retc
|
||
|
|
||
|
syncrecv:
|
||
|
// can receive from sleeping sender (sg)
|
||
|
if raceenabled {
|
||
|
if cas.elem != nil {
|
||
|
raceWriteObjectPC(c.elemtype, cas.elem, cas.pc, chanrecvpc)
|
||
|
}
|
||
|
racesync(c, sg)
|
||
|
}
|
||
|
selunlock(sel)
|
||
|
if debugSelect {
|
||
|
print("syncrecv: sel=", sel, " c=", c, "\n")
|
||
|
}
|
||
|
if cas.receivedp != nil {
|
||
|
*cas.receivedp = true
|
||
|
}
|
||
|
if cas.elem != nil {
|
||
|
memmove(cas.elem, sg.elem, uintptr(c.elemsize))
|
||
|
}
|
||
|
sg.elem = nil
|
||
|
gp = sg.g
|
||
|
gp.param = unsafe.Pointer(sg)
|
||
|
if sg.releasetime != 0 {
|
||
|
sg.releasetime = cputicks()
|
||
|
}
|
||
|
goready(gp)
|
||
|
goto retc
|
||
|
|
||
|
rclose:
|
||
|
// read at end of closed channel
|
||
|
selunlock(sel)
|
||
|
if cas.receivedp != nil {
|
||
|
*cas.receivedp = false
|
||
|
}
|
||
|
if cas.elem != nil {
|
||
|
memclr(cas.elem, uintptr(c.elemsize))
|
||
|
}
|
||
|
if raceenabled {
|
||
|
raceacquire(unsafe.Pointer(c))
|
||
|
}
|
||
|
goto retc
|
||
|
|
||
|
syncsend:
|
||
|
// can send to sleeping receiver (sg)
|
||
|
if raceenabled {
|
||
|
raceReadObjectPC(c.elemtype, cas.elem, cas.pc, chansendpc)
|
||
|
racesync(c, sg)
|
||
|
}
|
||
|
selunlock(sel)
|
||
|
if debugSelect {
|
||
|
print("syncsend: sel=", sel, " c=", c, "\n")
|
||
|
}
|
||
|
if sg.elem != nil {
|
||
|
memmove(sg.elem, cas.elem, uintptr(c.elemsize))
|
||
|
}
|
||
|
sg.elem = nil
|
||
|
gp = sg.g
|
||
|
gp.param = unsafe.Pointer(sg)
|
||
|
if sg.releasetime != 0 {
|
||
|
sg.releasetime = cputicks()
|
||
|
}
|
||
|
goready(gp)
|
||
|
|
||
|
retc:
|
||
|
if cas.releasetime > 0 {
|
||
|
blockevent(cas.releasetime-t0, 2)
|
||
|
}
|
||
|
return cas.pc, cas.so
|
||
|
|
||
|
sclose:
|
||
|
// send on closed channel
|
||
|
selunlock(sel)
|
||
|
panic("send on closed channel")
|
||
|
}
|
||
|
|
||
|
func (c *hchan) sortkey() uintptr {
|
||
|
// TODO(khr): if we have a moving garbage collector, we'll need to
|
||
|
// change this function.
|
||
|
return uintptr(unsafe.Pointer(c))
|
||
|
}
|
||
|
|
||
|
// A runtimeSelect is a single case passed to rselect.
|
||
|
// This must match ../reflect/value.go:/runtimeSelect
|
||
|
type runtimeSelect struct {
|
||
|
dir selectDir
|
||
|
typ unsafe.Pointer // channel type (not used here)
|
||
|
ch *hchan // channel
|
||
|
val unsafe.Pointer // ptr to data (SendDir) or ptr to receive buffer (RecvDir)
|
||
|
}
|
||
|
|
||
|
// These values must match ../reflect/value.go:/SelectDir.
|
||
|
type selectDir int
|
||
|
|
||
|
const (
|
||
|
_ selectDir = iota
|
||
|
selectSend // case Chan <- Send
|
||
|
selectRecv // case <-Chan:
|
||
|
selectDefault // default
|
||
|
)
|
||
|
|
||
|
func reflect_rselect(cases []runtimeSelect) (chosen int, recvOK bool) {
|
||
|
// flagNoScan is safe here, because all objects are also referenced from cases.
|
||
|
size := selectsize(uintptr(len(cases)))
|
||
|
sel := (*_select)(mallocgc(size, nil, flagNoScan))
|
||
|
newselect(sel, int64(size), int32(len(cases)))
|
||
|
r := new(bool)
|
||
|
for i := range cases {
|
||
|
rc := &cases[i]
|
||
|
switch rc.dir {
|
||
|
case selectDefault:
|
||
|
selectdefaultImpl(sel, uintptr(i), 0)
|
||
|
case selectSend:
|
||
|
if rc.ch == nil {
|
||
|
break
|
||
|
}
|
||
|
selectsendImpl(sel, rc.ch, uintptr(i), rc.val, 0)
|
||
|
case selectRecv:
|
||
|
if rc.ch == nil {
|
||
|
break
|
||
|
}
|
||
|
selectrecvImpl(sel, rc.ch, uintptr(i), rc.val, r, 0)
|
||
|
}
|
||
|
}
|
||
|
|
||
|
pc, _ := selectgoImpl(sel)
|
||
|
chosen = int(pc)
|
||
|
recvOK = *r
|
||
|
return
|
||
|
}
|
||
|
|
||
|
func (q *waitq) dequeueSudoG(s *sudog) {
|
||
|
var prevsgp *sudog
|
||
|
l := &q.first
|
||
|
for {
|
||
|
sgp := *l
|
||
|
if sgp == nil {
|
||
|
return
|
||
|
}
|
||
|
if sgp == s {
|
||
|
*l = sgp.next
|
||
|
if q.last == sgp {
|
||
|
q.last = prevsgp
|
||
|
}
|
||
|
s.next = nil
|
||
|
return
|
||
|
}
|
||
|
l = &sgp.next
|
||
|
prevsgp = sgp
|
||
|
}
|
||
|
}
|