mirror of
https://github.com/golang/go
synced 2024-10-04 14:31:21 -06:00
d89a738378
Update channel race annotations to support change in cl/75130045: doc: allow buffered channel as semaphore without initialization The new annotations are added only for channels with capacity 1. Strictly saying it's possible to construct a counter-example that will produce a false positive with capacity > 1. But it's hardly can lead to false positives in real programs, at least I would like to see such programs first. Any additional annotations also increase probability of false negatives, so I would prefer to add them lazily. LGTM=rsc R=golang-codereviews CC=golang-codereviews, iant, khr, rsc https://golang.org/cl/76970043
1160 lines
24 KiB
Plaintext
1160 lines
24 KiB
Plaintext
// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package runtime
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#include "runtime.h"
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#include "arch_GOARCH.h"
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#include "type.h"
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#include "race.h"
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#include "malloc.h"
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#include "chan.h"
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#include "../../cmd/ld/textflag.h"
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uint32 runtime·Hchansize = sizeof(Hchan);
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static void dequeueg(WaitQ*);
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static SudoG* dequeue(WaitQ*);
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static void enqueue(WaitQ*, SudoG*);
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static void destroychan(Hchan*);
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static void racesync(Hchan*, SudoG*);
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static Hchan*
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makechan(ChanType *t, int64 hint)
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{
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Hchan *c;
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Type *elem;
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elem = t->elem;
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// compiler checks this but be safe.
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if(elem->size >= (1<<16))
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runtime·throw("makechan: invalid channel element type");
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if((sizeof(*c)%MAXALIGN) != 0 || elem->align > MAXALIGN)
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runtime·throw("makechan: bad alignment");
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if(hint < 0 || (intgo)hint != hint || (elem->size > 0 && hint > (MaxMem - sizeof(*c)) / elem->size))
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runtime·panicstring("makechan: size out of range");
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// allocate memory in one call
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c = (Hchan*)runtime·mallocgc(sizeof(*c) + hint*elem->size, (uintptr)t | TypeInfo_Chan, 0);
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c->elemsize = elem->size;
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c->elemtype = elem;
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c->dataqsiz = hint;
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if(debug)
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runtime·printf("makechan: chan=%p; elemsize=%D; elemalg=%p; dataqsiz=%D\n",
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c, (int64)elem->size, elem->alg, (int64)c->dataqsiz);
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return c;
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}
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func reflect·makechan(t *ChanType, size uint64) (c *Hchan) {
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c = makechan(t, size);
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}
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func makechan(t *ChanType, size int64) (c *Hchan) {
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c = makechan(t, size);
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}
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/*
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* generic single channel send/recv
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* if the bool pointer is nil,
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* then the full exchange will
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* occur. if pres is not nil,
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* then the protocol will not
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* sleep but return if it could
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* not complete.
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*
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* sleep can wake up with g->param == nil
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* when a channel involved in the sleep has
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* been closed. it is easiest to loop and re-run
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* the operation; we'll see that it's now closed.
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*/
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static bool
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chansend(ChanType *t, Hchan *c, byte *ep, bool block, void *pc)
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{
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SudoG *sg;
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SudoG mysg;
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G* gp;
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int64 t0;
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if(raceenabled)
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runtime·racereadobjectpc(ep, t->elem, runtime·getcallerpc(&t), chansend);
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if(c == nil) {
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USED(t);
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if(!block)
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return false;
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runtime·park(nil, nil, "chan send (nil chan)");
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return false; // not reached
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}
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if(debug) {
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runtime·printf("chansend: chan=%p; elem=", c);
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c->elemtype->alg->print(c->elemsize, ep);
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runtime·prints("\n");
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}
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t0 = 0;
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mysg.releasetime = 0;
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if(runtime·blockprofilerate > 0) {
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t0 = runtime·cputicks();
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mysg.releasetime = -1;
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}
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runtime·lock(c);
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if(raceenabled)
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runtime·racereadpc(c, pc, chansend);
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if(c->closed)
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goto closed;
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if(c->dataqsiz > 0)
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goto asynch;
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sg = dequeue(&c->recvq);
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if(sg != nil) {
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if(raceenabled)
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racesync(c, sg);
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runtime·unlock(c);
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gp = sg->g;
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gp->param = sg;
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if(sg->elem != nil)
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c->elemtype->alg->copy(c->elemsize, sg->elem, ep);
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if(sg->releasetime)
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sg->releasetime = runtime·cputicks();
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runtime·ready(gp);
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return true;
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}
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if(!block) {
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runtime·unlock(c);
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return false;
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}
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mysg.elem = ep;
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mysg.g = g;
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mysg.selectdone = nil;
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g->param = nil;
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enqueue(&c->sendq, &mysg);
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runtime·parkunlock(c, "chan send");
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if(g->param == nil) {
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runtime·lock(c);
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if(!c->closed)
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runtime·throw("chansend: spurious wakeup");
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goto closed;
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}
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if(mysg.releasetime > 0)
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runtime·blockevent(mysg.releasetime - t0, 2);
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return true;
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asynch:
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if(c->closed)
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goto closed;
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if(c->qcount >= c->dataqsiz) {
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if(!block) {
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runtime·unlock(c);
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return false;
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}
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mysg.g = g;
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mysg.elem = nil;
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mysg.selectdone = nil;
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enqueue(&c->sendq, &mysg);
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runtime·parkunlock(c, "chan send");
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runtime·lock(c);
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goto asynch;
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}
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if(raceenabled) {
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if(c->dataqsiz == 1)
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runtime·raceacquire(chanbuf(c, c->sendx));
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runtime·racerelease(chanbuf(c, c->sendx));
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}
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c->elemtype->alg->copy(c->elemsize, chanbuf(c, c->sendx), ep);
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if(++c->sendx == c->dataqsiz)
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c->sendx = 0;
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c->qcount++;
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sg = dequeue(&c->recvq);
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if(sg != nil) {
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gp = sg->g;
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runtime·unlock(c);
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if(sg->releasetime)
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sg->releasetime = runtime·cputicks();
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runtime·ready(gp);
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} else
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runtime·unlock(c);
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if(mysg.releasetime > 0)
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runtime·blockevent(mysg.releasetime - t0, 2);
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return true;
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closed:
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runtime·unlock(c);
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runtime·panicstring("send on closed channel");
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return false; // not reached
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}
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static bool
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chanrecv(ChanType *t, Hchan* c, byte *ep, bool block, bool *received)
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{
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SudoG *sg;
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SudoG mysg;
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G *gp;
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int64 t0;
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// raceenabled: don't need to check ep, as it is always on the stack.
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if(debug)
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runtime·printf("chanrecv: chan=%p\n", c);
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if(c == nil) {
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USED(t);
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if(!block)
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return false;
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runtime·park(nil, nil, "chan receive (nil chan)");
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return false; // not reached
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}
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t0 = 0;
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mysg.releasetime = 0;
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if(runtime·blockprofilerate > 0) {
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t0 = runtime·cputicks();
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mysg.releasetime = -1;
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}
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runtime·lock(c);
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if(c->dataqsiz > 0)
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goto asynch;
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if(c->closed)
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goto closed;
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sg = dequeue(&c->sendq);
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if(sg != nil) {
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if(raceenabled)
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racesync(c, sg);
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runtime·unlock(c);
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if(ep != nil)
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c->elemtype->alg->copy(c->elemsize, ep, sg->elem);
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gp = sg->g;
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gp->param = sg;
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if(sg->releasetime)
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sg->releasetime = runtime·cputicks();
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runtime·ready(gp);
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if(received != nil)
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*received = true;
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return true;
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}
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if(!block) {
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runtime·unlock(c);
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return false;
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}
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mysg.elem = ep;
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mysg.g = g;
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mysg.selectdone = nil;
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g->param = nil;
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enqueue(&c->recvq, &mysg);
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runtime·parkunlock(c, "chan receive");
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if(g->param == nil) {
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runtime·lock(c);
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if(!c->closed)
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runtime·throw("chanrecv: spurious wakeup");
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goto closed;
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}
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if(received != nil)
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*received = true;
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if(mysg.releasetime > 0)
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runtime·blockevent(mysg.releasetime - t0, 2);
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return true;
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asynch:
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if(c->qcount <= 0) {
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if(c->closed)
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goto closed;
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if(!block) {
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runtime·unlock(c);
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if(received != nil)
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*received = false;
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return false;
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}
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mysg.g = g;
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mysg.elem = nil;
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mysg.selectdone = nil;
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enqueue(&c->recvq, &mysg);
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runtime·parkunlock(c, "chan receive");
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runtime·lock(c);
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goto asynch;
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}
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if(raceenabled) {
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runtime·raceacquire(chanbuf(c, c->recvx));
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if(c->dataqsiz == 1)
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runtime·racerelease(chanbuf(c, c->recvx));
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}
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if(ep != nil)
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c->elemtype->alg->copy(c->elemsize, ep, chanbuf(c, c->recvx));
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c->elemtype->alg->copy(c->elemsize, chanbuf(c, c->recvx), nil);
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if(++c->recvx == c->dataqsiz)
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c->recvx = 0;
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c->qcount--;
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sg = dequeue(&c->sendq);
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if(sg != nil) {
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gp = sg->g;
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runtime·unlock(c);
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if(sg->releasetime)
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sg->releasetime = runtime·cputicks();
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runtime·ready(gp);
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} else
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runtime·unlock(c);
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if(received != nil)
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*received = true;
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if(mysg.releasetime > 0)
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runtime·blockevent(mysg.releasetime - t0, 2);
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return true;
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closed:
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if(ep != nil)
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c->elemtype->alg->copy(c->elemsize, ep, nil);
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if(received != nil)
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*received = false;
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if(raceenabled)
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runtime·raceacquire(c);
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runtime·unlock(c);
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if(mysg.releasetime > 0)
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runtime·blockevent(mysg.releasetime - t0, 2);
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return true;
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}
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#pragma textflag NOSPLIT
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func chansend1(t *ChanType, c *Hchan, elem *byte) {
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chansend(t, c, elem, true, runtime·getcallerpc(&t));
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}
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#pragma textflag NOSPLIT
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func chanrecv1(t *ChanType, c *Hchan, elem *byte) {
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chanrecv(t, c, elem, true, nil);
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}
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// chanrecv2(hchan *chan any, elem *any) (received bool);
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#pragma textflag NOSPLIT
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func chanrecv2(t *ChanType, c *Hchan, elem *byte) (received bool) {
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chanrecv(t, c, elem, true, &received);
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}
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// compiler implements
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//
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// select {
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// case c <- v:
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// ... foo
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// default:
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// ... bar
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// }
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//
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// as
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//
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// if selectnbsend(c, v) {
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// ... foo
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// } else {
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// ... bar
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// }
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//
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#pragma textflag NOSPLIT
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func selectnbsend(t *ChanType, c *Hchan, elem *byte) (selected bool) {
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selected = chansend(t, c, elem, false, runtime·getcallerpc(&t));
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}
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// compiler implements
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//
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// select {
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// case v = <-c:
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// ... foo
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// default:
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// ... bar
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// }
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//
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// as
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//
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// if selectnbrecv(&v, c) {
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// ... foo
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// } else {
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// ... bar
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// }
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//
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#pragma textflag NOSPLIT
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func selectnbrecv(t *ChanType, elem *byte, c *Hchan) (selected bool) {
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selected = chanrecv(t, c, elem, false, nil);
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}
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// compiler implements
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//
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// select {
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// case v, ok = <-c:
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// ... foo
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// default:
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// ... bar
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// }
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//
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// as
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//
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// if c != nil && selectnbrecv2(&v, &ok, c) {
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// ... foo
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// } else {
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// ... bar
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// }
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//
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#pragma textflag NOSPLIT
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func selectnbrecv2(t *ChanType, elem *byte, received *bool, c *Hchan) (selected bool) {
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selected = chanrecv(t, c, elem, false, received);
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}
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#pragma textflag NOSPLIT
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func reflect·chansend(t *ChanType, c *Hchan, elem *byte, nb bool) (selected bool) {
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selected = chansend(t, c, elem, !nb, runtime·getcallerpc(&t));
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}
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func reflect·chanrecv(t *ChanType, c *Hchan, nb bool, elem *byte) (selected bool, received bool) {
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received = false;
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selected = chanrecv(t, c, elem, !nb, &received);
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}
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static Select* newselect(int32);
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#pragma textflag NOSPLIT
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func newselect(size int32) (sel *byte) {
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sel = (byte*)newselect(size);
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}
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static Select*
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newselect(int32 size)
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{
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int32 n;
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Select *sel;
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n = 0;
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if(size > 1)
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n = size-1;
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// allocate all the memory we need in a single allocation
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// start with Select with size cases
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// then lockorder with size entries
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// then pollorder with size entries
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sel = runtime·mal(sizeof(*sel) +
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n*sizeof(sel->scase[0]) +
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size*sizeof(sel->lockorder[0]) +
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size*sizeof(sel->pollorder[0]));
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sel->tcase = size;
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sel->ncase = 0;
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sel->lockorder = (void*)(sel->scase + size);
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sel->pollorder = (void*)(sel->lockorder + size);
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if(debug)
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runtime·printf("newselect s=%p size=%d\n", sel, size);
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return sel;
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}
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// cut in half to give stack a chance to split
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static void selectsend(Select *sel, Hchan *c, void *pc, void *elem, int32 so);
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#pragma textflag NOSPLIT
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func selectsend(sel *Select, c *Hchan, elem *byte) (selected bool) {
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selected = false;
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// nil cases do not compete
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if(c != nil)
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selectsend(sel, c, runtime·getcallerpc(&sel), elem, (byte*)&selected - (byte*)&sel);
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}
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static void
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selectsend(Select *sel, Hchan *c, void *pc, void *elem, int32 so)
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{
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int32 i;
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Scase *cas;
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i = sel->ncase;
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if(i >= sel->tcase)
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runtime·throw("selectsend: too many cases");
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sel->ncase = i+1;
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cas = &sel->scase[i];
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cas->pc = pc;
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cas->chan = c;
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cas->so = so;
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cas->kind = CaseSend;
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cas->sg.elem = elem;
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if(debug)
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runtime·printf("selectsend s=%p pc=%p chan=%p so=%d\n",
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sel, cas->pc, cas->chan, cas->so);
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}
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// cut in half to give stack a chance to split
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static void selectrecv(Select *sel, Hchan *c, void *pc, void *elem, bool*, int32 so);
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#pragma textflag NOSPLIT
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func selectrecv(sel *Select, c *Hchan, elem *byte) (selected bool) {
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selected = false;
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// nil cases do not compete
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if(c != nil)
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selectrecv(sel, c, runtime·getcallerpc(&sel), elem, nil, (byte*)&selected - (byte*)&sel);
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}
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#pragma textflag NOSPLIT
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func selectrecv2(sel *Select, c *Hchan, elem *byte, received *bool) (selected bool) {
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selected = false;
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// nil cases do not compete
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if(c != nil)
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selectrecv(sel, c, runtime·getcallerpc(&sel), elem, received, (byte*)&selected - (byte*)&sel);
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}
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|
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static void
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selectrecv(Select *sel, Hchan *c, void *pc, void *elem, bool *received, int32 so)
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{
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int32 i;
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Scase *cas;
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i = sel->ncase;
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if(i >= sel->tcase)
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runtime·throw("selectrecv: too many cases");
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sel->ncase = i+1;
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cas = &sel->scase[i];
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cas->pc = pc;
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cas->chan = c;
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cas->so = so;
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cas->kind = CaseRecv;
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cas->sg.elem = elem;
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cas->receivedp = received;
|
|
|
|
if(debug)
|
|
runtime·printf("selectrecv s=%p pc=%p chan=%p so=%d\n",
|
|
sel, cas->pc, cas->chan, cas->so);
|
|
}
|
|
|
|
// cut in half to give stack a chance to split
|
|
static void selectdefault(Select*, void*, int32);
|
|
|
|
#pragma textflag NOSPLIT
|
|
func selectdefault(sel *Select) (selected bool) {
|
|
selected = false;
|
|
selectdefault(sel, runtime·getcallerpc(&sel), (byte*)&selected - (byte*)&sel);
|
|
}
|
|
|
|
static void
|
|
selectdefault(Select *sel, void *callerpc, int32 so)
|
|
{
|
|
int32 i;
|
|
Scase *cas;
|
|
|
|
i = sel->ncase;
|
|
if(i >= sel->tcase)
|
|
runtime·throw("selectdefault: too many cases");
|
|
sel->ncase = i+1;
|
|
cas = &sel->scase[i];
|
|
cas->pc = callerpc;
|
|
cas->chan = nil;
|
|
|
|
cas->so = so;
|
|
cas->kind = CaseDefault;
|
|
|
|
if(debug)
|
|
runtime·printf("selectdefault s=%p pc=%p so=%d\n",
|
|
sel, cas->pc, cas->so);
|
|
}
|
|
|
|
static void
|
|
sellock(Select *sel)
|
|
{
|
|
uint32 i;
|
|
Hchan *c, *c0;
|
|
|
|
c = nil;
|
|
for(i=0; i<sel->ncase; i++) {
|
|
c0 = sel->lockorder[i];
|
|
if(c0 && c0 != c) {
|
|
c = sel->lockorder[i];
|
|
runtime·lock(c);
|
|
}
|
|
}
|
|
}
|
|
|
|
static void
|
|
selunlock(Select *sel)
|
|
{
|
|
int32 i, n, r;
|
|
Hchan *c;
|
|
|
|
// 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 = (int32)sel->ncase;
|
|
r = 0;
|
|
// skip the default case
|
|
if(n>0 && sel->lockorder[0] == nil)
|
|
r = 1;
|
|
for(i = n-1; i >= r; i--) {
|
|
c = sel->lockorder[i];
|
|
if(i>0 && sel->lockorder[i-1] == c)
|
|
continue; // will unlock it on the next iteration
|
|
runtime·unlock(c);
|
|
}
|
|
}
|
|
|
|
static bool
|
|
selparkcommit(G *gp, void *sel)
|
|
{
|
|
USED(gp);
|
|
selunlock(sel);
|
|
return true;
|
|
}
|
|
|
|
func block() {
|
|
runtime·park(nil, nil, "select (no cases)"); // forever
|
|
}
|
|
|
|
static void* selectgo(Select**);
|
|
|
|
// selectgo(sel *byte);
|
|
//
|
|
// overwrites return pc on stack to signal which case of the select
|
|
// to run, so cannot appear at the top of a split stack.
|
|
#pragma textflag NOSPLIT
|
|
func selectgo(sel *Select) {
|
|
runtime·setcallerpc(&sel, selectgo(&sel));
|
|
}
|
|
|
|
static void*
|
|
selectgo(Select **selp)
|
|
{
|
|
Select *sel;
|
|
uint32 o, i, j, k, done;
|
|
int64 t0;
|
|
Scase *cas, *dfl;
|
|
Hchan *c;
|
|
SudoG *sg;
|
|
G *gp;
|
|
byte *as;
|
|
void *pc;
|
|
|
|
sel = *selp;
|
|
|
|
if(debug)
|
|
runtime·printf("select: sel=%p\n", sel);
|
|
|
|
t0 = 0;
|
|
if(runtime·blockprofilerate > 0) {
|
|
t0 = runtime·cputicks();
|
|
for(i=0; i<sel->ncase; i++)
|
|
sel->scase[i].sg.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
|
|
for(i=0; i<sel->ncase; i++)
|
|
sel->pollorder[i] = i;
|
|
for(i=1; i<sel->ncase; i++) {
|
|
o = sel->pollorder[i];
|
|
j = runtime·fastrand1()%(i+1);
|
|
sel->pollorder[i] = sel->pollorder[j];
|
|
sel->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.
|
|
for(i=0; i<sel->ncase; i++) {
|
|
j = i;
|
|
c = sel->scase[j].chan;
|
|
while(j > 0 && sel->lockorder[k=(j-1)/2] < c) {
|
|
sel->lockorder[j] = sel->lockorder[k];
|
|
j = k;
|
|
}
|
|
sel->lockorder[j] = c;
|
|
}
|
|
for(i=sel->ncase; i-->0; ) {
|
|
c = sel->lockorder[i];
|
|
sel->lockorder[i] = sel->lockorder[0];
|
|
j = 0;
|
|
for(;;) {
|
|
k = j*2+1;
|
|
if(k >= i)
|
|
break;
|
|
if(k+1 < i && sel->lockorder[k] < sel->lockorder[k+1])
|
|
k++;
|
|
if(c < sel->lockorder[k]) {
|
|
sel->lockorder[j] = sel->lockorder[k];
|
|
j = k;
|
|
continue;
|
|
}
|
|
break;
|
|
}
|
|
sel->lockorder[j] = c;
|
|
}
|
|
/*
|
|
for(i=0; i+1<sel->ncase; i++)
|
|
if(sel->lockorder[i] > sel->lockorder[i+1]) {
|
|
runtime·printf("i=%d %p %p\n", i, sel->lockorder[i], sel->lockorder[i+1]);
|
|
runtime·throw("select: broken sort");
|
|
}
|
|
*/
|
|
sellock(sel);
|
|
|
|
loop:
|
|
// pass 1 - look for something already waiting
|
|
dfl = nil;
|
|
for(i=0; i<sel->ncase; i++) {
|
|
o = sel->pollorder[i];
|
|
cas = &sel->scase[o];
|
|
c = cas->chan;
|
|
|
|
switch(cas->kind) {
|
|
case CaseRecv:
|
|
if(c->dataqsiz > 0) {
|
|
if(c->qcount > 0)
|
|
goto asyncrecv;
|
|
} else {
|
|
sg = dequeue(&c->sendq);
|
|
if(sg != nil)
|
|
goto syncrecv;
|
|
}
|
|
if(c->closed)
|
|
goto rclose;
|
|
break;
|
|
|
|
case CaseSend:
|
|
if(raceenabled)
|
|
runtime·racereadpc(c, cas->pc, chansend);
|
|
if(c->closed)
|
|
goto sclose;
|
|
if(c->dataqsiz > 0) {
|
|
if(c->qcount < c->dataqsiz)
|
|
goto asyncsend;
|
|
} else {
|
|
sg = dequeue(&c->recvq);
|
|
if(sg != nil)
|
|
goto syncsend;
|
|
}
|
|
break;
|
|
|
|
case CaseDefault:
|
|
dfl = cas;
|
|
break;
|
|
}
|
|
}
|
|
|
|
if(dfl != nil) {
|
|
selunlock(sel);
|
|
cas = dfl;
|
|
goto retc;
|
|
}
|
|
|
|
|
|
// pass 2 - enqueue on all chans
|
|
done = 0;
|
|
for(i=0; i<sel->ncase; i++) {
|
|
o = sel->pollorder[i];
|
|
cas = &sel->scase[o];
|
|
c = cas->chan;
|
|
sg = &cas->sg;
|
|
sg->g = g;
|
|
sg->selectdone = &done;
|
|
|
|
switch(cas->kind) {
|
|
case CaseRecv:
|
|
enqueue(&c->recvq, sg);
|
|
break;
|
|
|
|
case CaseSend:
|
|
enqueue(&c->sendq, sg);
|
|
break;
|
|
}
|
|
}
|
|
|
|
g->param = nil;
|
|
runtime·park(selparkcommit, sel, "select");
|
|
|
|
sellock(sel);
|
|
sg = g->param;
|
|
|
|
// pass 3 - dequeue from unsuccessful chans
|
|
// otherwise they stack up on quiet channels
|
|
for(i=0; i<sel->ncase; i++) {
|
|
cas = &sel->scase[i];
|
|
if(cas != (Scase*)sg) {
|
|
c = cas->chan;
|
|
if(cas->kind == CaseSend)
|
|
dequeueg(&c->sendq);
|
|
else
|
|
dequeueg(&c->recvq);
|
|
}
|
|
}
|
|
|
|
if(sg == nil)
|
|
goto loop;
|
|
|
|
cas = (Scase*)sg;
|
|
c = cas->chan;
|
|
|
|
if(c->dataqsiz > 0)
|
|
runtime·throw("selectgo: shouldn't happen");
|
|
|
|
if(debug)
|
|
runtime·printf("wait-return: sel=%p c=%p cas=%p kind=%d\n",
|
|
sel, c, cas, cas->kind);
|
|
|
|
if(cas->kind == CaseRecv) {
|
|
if(cas->receivedp != nil)
|
|
*cas->receivedp = true;
|
|
}
|
|
|
|
if(raceenabled) {
|
|
if(cas->kind == CaseRecv && cas->sg.elem != nil)
|
|
runtime·racewriteobjectpc(cas->sg.elem, c->elemtype, cas->pc, chanrecv);
|
|
else if(cas->kind == CaseSend)
|
|
runtime·racereadobjectpc(cas->sg.elem, c->elemtype, cas->pc, chansend);
|
|
}
|
|
|
|
selunlock(sel);
|
|
goto retc;
|
|
|
|
asyncrecv:
|
|
// can receive from buffer
|
|
if(raceenabled) {
|
|
if(cas->sg.elem != nil)
|
|
runtime·racewriteobjectpc(cas->sg.elem, c->elemtype, cas->pc, chanrecv);
|
|
runtime·raceacquire(chanbuf(c, c->recvx));
|
|
if(c->dataqsiz == 1)
|
|
runtime·racerelease(chanbuf(c, c->recvx));
|
|
}
|
|
if(cas->receivedp != nil)
|
|
*cas->receivedp = true;
|
|
if(cas->sg.elem != nil)
|
|
c->elemtype->alg->copy(c->elemsize, cas->sg.elem, chanbuf(c, c->recvx));
|
|
c->elemtype->alg->copy(c->elemsize, chanbuf(c, c->recvx), nil);
|
|
if(++c->recvx == c->dataqsiz)
|
|
c->recvx = 0;
|
|
c->qcount--;
|
|
sg = dequeue(&c->sendq);
|
|
if(sg != nil) {
|
|
gp = sg->g;
|
|
selunlock(sel);
|
|
if(sg->releasetime)
|
|
sg->releasetime = runtime·cputicks();
|
|
runtime·ready(gp);
|
|
} else {
|
|
selunlock(sel);
|
|
}
|
|
goto retc;
|
|
|
|
asyncsend:
|
|
// can send to buffer
|
|
if(raceenabled) {
|
|
if(c->dataqsiz == 1)
|
|
runtime·raceacquire(chanbuf(c, c->sendx));
|
|
runtime·racerelease(chanbuf(c, c->sendx));
|
|
runtime·racereadobjectpc(cas->sg.elem, c->elemtype, cas->pc, chansend);
|
|
}
|
|
c->elemtype->alg->copy(c->elemsize, chanbuf(c, c->sendx), cas->sg.elem);
|
|
if(++c->sendx == c->dataqsiz)
|
|
c->sendx = 0;
|
|
c->qcount++;
|
|
sg = dequeue(&c->recvq);
|
|
if(sg != nil) {
|
|
gp = sg->g;
|
|
selunlock(sel);
|
|
if(sg->releasetime)
|
|
sg->releasetime = runtime·cputicks();
|
|
runtime·ready(gp);
|
|
} else {
|
|
selunlock(sel);
|
|
}
|
|
goto retc;
|
|
|
|
syncrecv:
|
|
// can receive from sleeping sender (sg)
|
|
if(raceenabled) {
|
|
if(cas->sg.elem != nil)
|
|
runtime·racewriteobjectpc(cas->sg.elem, c->elemtype, cas->pc, chanrecv);
|
|
racesync(c, sg);
|
|
}
|
|
selunlock(sel);
|
|
if(debug)
|
|
runtime·printf("syncrecv: sel=%p c=%p o=%d\n", sel, c, o);
|
|
if(cas->receivedp != nil)
|
|
*cas->receivedp = true;
|
|
if(cas->sg.elem != nil)
|
|
c->elemtype->alg->copy(c->elemsize, cas->sg.elem, sg->elem);
|
|
gp = sg->g;
|
|
gp->param = sg;
|
|
if(sg->releasetime)
|
|
sg->releasetime = runtime·cputicks();
|
|
runtime·ready(gp);
|
|
goto retc;
|
|
|
|
rclose:
|
|
// read at end of closed channel
|
|
selunlock(sel);
|
|
if(cas->receivedp != nil)
|
|
*cas->receivedp = false;
|
|
if(cas->sg.elem != nil)
|
|
c->elemtype->alg->copy(c->elemsize, cas->sg.elem, nil);
|
|
if(raceenabled)
|
|
runtime·raceacquire(c);
|
|
goto retc;
|
|
|
|
syncsend:
|
|
// can send to sleeping receiver (sg)
|
|
if(raceenabled) {
|
|
runtime·racereadobjectpc(cas->sg.elem, c->elemtype, cas->pc, chansend);
|
|
racesync(c, sg);
|
|
}
|
|
selunlock(sel);
|
|
if(debug)
|
|
runtime·printf("syncsend: sel=%p c=%p o=%d\n", sel, c, o);
|
|
if(sg->elem != nil)
|
|
c->elemtype->alg->copy(c->elemsize, sg->elem, cas->sg.elem);
|
|
gp = sg->g;
|
|
gp->param = sg;
|
|
if(sg->releasetime)
|
|
sg->releasetime = runtime·cputicks();
|
|
runtime·ready(gp);
|
|
|
|
retc:
|
|
// return pc corresponding to chosen case.
|
|
// Set boolean passed during select creation
|
|
// (at offset selp + cas->so) to true.
|
|
// If cas->so == 0, this is a reflect-driven select and we
|
|
// don't need to update the boolean.
|
|
pc = cas->pc;
|
|
if(cas->so > 0) {
|
|
as = (byte*)selp + cas->so;
|
|
*as = true;
|
|
}
|
|
if(cas->sg.releasetime > 0)
|
|
runtime·blockevent(cas->sg.releasetime - t0, 2);
|
|
runtime·free(sel);
|
|
return pc;
|
|
|
|
sclose:
|
|
// send on closed channel
|
|
selunlock(sel);
|
|
runtime·panicstring("send on closed channel");
|
|
return nil; // not reached
|
|
}
|
|
|
|
// This struct must match ../reflect/value.go:/runtimeSelect.
|
|
typedef struct runtimeSelect runtimeSelect;
|
|
struct runtimeSelect
|
|
{
|
|
uintptr dir;
|
|
ChanType *typ;
|
|
Hchan *ch;
|
|
byte *val;
|
|
};
|
|
|
|
// This enum must match ../reflect/value.go:/SelectDir.
|
|
enum SelectDir {
|
|
SelectSend = 1,
|
|
SelectRecv,
|
|
SelectDefault,
|
|
};
|
|
|
|
func reflect·rselect(cases Slice) (chosen int, recvOK bool) {
|
|
int32 i;
|
|
Select *sel;
|
|
runtimeSelect* rcase, *rc;
|
|
|
|
chosen = -1;
|
|
recvOK = false;
|
|
|
|
rcase = (runtimeSelect*)cases.array;
|
|
|
|
sel = newselect(cases.len);
|
|
for(i=0; i<cases.len; i++) {
|
|
rc = &rcase[i];
|
|
switch(rc->dir) {
|
|
case SelectDefault:
|
|
selectdefault(sel, (void*)i, 0);
|
|
break;
|
|
case SelectSend:
|
|
if(rc->ch == nil)
|
|
break;
|
|
selectsend(sel, rc->ch, (void*)i, rc->val, 0);
|
|
break;
|
|
case SelectRecv:
|
|
if(rc->ch == nil)
|
|
break;
|
|
selectrecv(sel, rc->ch, (void*)i, rc->val, &recvOK, 0);
|
|
break;
|
|
}
|
|
}
|
|
|
|
chosen = (intgo)(uintptr)selectgo(&sel);
|
|
}
|
|
|
|
static void closechan(Hchan *c, void *pc);
|
|
|
|
#pragma textflag NOSPLIT
|
|
func closechan(c *Hchan) {
|
|
closechan(c, runtime·getcallerpc(&c));
|
|
}
|
|
|
|
#pragma textflag NOSPLIT
|
|
func reflect·chanclose(c *Hchan) {
|
|
closechan(c, runtime·getcallerpc(&c));
|
|
}
|
|
|
|
static void
|
|
closechan(Hchan *c, void *pc)
|
|
{
|
|
SudoG *sg;
|
|
G* gp;
|
|
|
|
if(c == nil)
|
|
runtime·panicstring("close of nil channel");
|
|
|
|
runtime·lock(c);
|
|
if(c->closed) {
|
|
runtime·unlock(c);
|
|
runtime·panicstring("close of closed channel");
|
|
}
|
|
|
|
if(raceenabled) {
|
|
runtime·racewritepc(c, pc, runtime·closechan);
|
|
runtime·racerelease(c);
|
|
}
|
|
|
|
c->closed = true;
|
|
|
|
// release all readers
|
|
for(;;) {
|
|
sg = dequeue(&c->recvq);
|
|
if(sg == nil)
|
|
break;
|
|
gp = sg->g;
|
|
gp->param = nil;
|
|
if(sg->releasetime)
|
|
sg->releasetime = runtime·cputicks();
|
|
runtime·ready(gp);
|
|
}
|
|
|
|
// release all writers
|
|
for(;;) {
|
|
sg = dequeue(&c->sendq);
|
|
if(sg == nil)
|
|
break;
|
|
gp = sg->g;
|
|
gp->param = nil;
|
|
if(sg->releasetime)
|
|
sg->releasetime = runtime·cputicks();
|
|
runtime·ready(gp);
|
|
}
|
|
|
|
runtime·unlock(c);
|
|
}
|
|
|
|
func reflect·chanlen(c *Hchan) (len int) {
|
|
if(c == nil)
|
|
len = 0;
|
|
else
|
|
len = c->qcount;
|
|
}
|
|
|
|
func reflect·chancap(c *Hchan) (cap int) {
|
|
if(c == nil)
|
|
cap = 0;
|
|
else
|
|
cap = c->dataqsiz;
|
|
}
|
|
|
|
static SudoG*
|
|
dequeue(WaitQ *q)
|
|
{
|
|
SudoG *sgp;
|
|
|
|
loop:
|
|
sgp = q->first;
|
|
if(sgp == nil)
|
|
return nil;
|
|
q->first = sgp->link;
|
|
|
|
// if sgp participates in a select and is already signaled, ignore it
|
|
if(sgp->selectdone != nil) {
|
|
// claim the right to signal
|
|
if(*sgp->selectdone != 0 || !runtime·cas(sgp->selectdone, 0, 1))
|
|
goto loop;
|
|
}
|
|
|
|
return sgp;
|
|
}
|
|
|
|
static void
|
|
dequeueg(WaitQ *q)
|
|
{
|
|
SudoG **l, *sgp, *prevsgp;
|
|
|
|
prevsgp = nil;
|
|
for(l=&q->first; (sgp=*l) != nil; l=&sgp->link, prevsgp=sgp) {
|
|
if(sgp->g == g) {
|
|
*l = sgp->link;
|
|
if(q->last == sgp)
|
|
q->last = prevsgp;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
static void
|
|
enqueue(WaitQ *q, SudoG *sgp)
|
|
{
|
|
sgp->link = nil;
|
|
if(q->first == nil) {
|
|
q->first = sgp;
|
|
q->last = sgp;
|
|
return;
|
|
}
|
|
q->last->link = sgp;
|
|
q->last = sgp;
|
|
}
|
|
|
|
static void
|
|
racesync(Hchan *c, SudoG *sg)
|
|
{
|
|
runtime·racerelease(chanbuf(c, 0));
|
|
runtime·raceacquireg(sg->g, chanbuf(c, 0));
|
|
runtime·racereleaseg(sg->g, chanbuf(c, 0));
|
|
runtime·raceacquire(chanbuf(c, 0));
|
|
}
|