runtime/internal/lib/sync: fix sync.Pool for pthread

runtime/build.go

@@ -61,6 +61,7 @@ var altPkgs = map[string]altPkgSpec{
 	"reflect":                 {mode: altPkgReplace},
 	"runtime":                 {mode: altPkgReplace},
 	"sync/atomic":             {mode: altPkgReplace},
+	"sync":                    {mode: altPkgReplace},
 	"syscall/js":              {mode: altPkgReplace},
 	"syscall":                 {mode: altPkgReplace},
 	"unique":                  {mode: altPkgReplace},

runtime/internal/lib/runtime/sync_runtime_llgo.go

@@ -2,7 +2,10 @@
 
 package runtime
 
-import _ "unsafe"
+import (
+	_ "sync/atomic"
+	_ "unsafe"
+)
 
 var poolCleanup func()
 

runtime/internal/lib/runtime/unique_runtime_llgo.go

@@ -3,8 +3,9 @@
 package runtime
 
 import (
-	"sync"
 	_ "unsafe"
+
+	"github.com/goplus/llgo/runtime/internal/clite/pthread/sync"
 )
 
 var (
@@ -13,15 +14,17 @@ var (
 )
 
 //go:linkname unique_runtime_registerUniqueMapCleanup unique.runtime_registerUniqueMapCleanup
-func unique_runtime_registerUniqueMapCleanup(cleanup func()) {
+func unique_runtime_registerUniqueMapCleanup(f func()) {
 	uniqueMapCleanupOnce.Do(func() {
 		uniqueMapCleanup = make(chan struct{}, 1)
-		go func() {
-			for range uniqueMapCleanup {
-				cleanup()
-			}
-		}()
 	})
+	// Start the goroutine in the runtime so it's counted as a system goroutine.
+	go func(cleanup func()) {
+		for {
+			<-uniqueMapCleanup
+			cleanup()
+		}
+	}(f)
 }
 
 func unique_runtime_notifyMapCleanup() {

runtime/internal/lib/sync/pool.go

@@ -0,0 +1,184 @@
+// Copyright 2013 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 sync
+
+import (
+	"sync"
+	"sync/atomic"
+	"unsafe"
+
+	"github.com/goplus/llgo/runtime/internal/clite/tls"
+)
+
+// A Pool is a set of temporary objects that may be individually saved and
+// retrieved.
+//
+// Any item stored in the Pool may be removed automatically at any time without
+// notification. If the Pool holds the only reference when this happens, the
+// item might be deallocated.
+//
+// A Pool is safe for use by multiple goroutines simultaneously.
+//
+// Pool's purpose is to cache allocated but unused items for later reuse,
+// relieving pressure on the garbage collector. That is, it makes it easy to
+// build efficient, thread-safe free lists. However, it is not suitable for all
+// free lists.
+//
+// An appropriate use of a Pool is to manage a group of temporary items
+// silently shared among and potentially reused by concurrent independent
+// clients of a package. Pool provides a way to amortize allocation overhead
+// across many clients.
+//
+// An example of good use of a Pool is in the fmt package, which maintains a
+// dynamically-sized store of temporary output buffers. The store scales under
+// load (when many goroutines are actively printing) and shrinks when
+// quiescent.
+//
+// On the other hand, a free list maintained as part of a short-lived object is
+// not a suitable use for a Pool, since the overhead does not amortize well in
+// that scenario. It is more efficient to have such objects implement their own
+// free list.
+//
+// A Pool must not be copied after first use.
+//
+// In the terminology of [the Go memory model], a call to Put(x) “synchronizes before”
+// a call to [Pool.Get] returning that same value x.
+// Similarly, a call to New returning x “synchronizes before”
+// a call to Get returning that same value x.
+//
+// [the Go memory model]: https://go.dev/ref/mem
+type Pool struct {
+	noCopy noCopy
+
+	local     unsafe.Pointer // local fixed-size per-P pool, actual type is [P]poolLocal
+	localSize uintptr        // size of the local array
+
+	victim     unsafe.Pointer // local from previous cycle
+	victimSize uintptr        // size of victims array
+
+	// New optionally specifies a function to generate
+	// a value when Get would otherwise return nil.
+	// It may not be changed concurrently with calls to Get.
+	New  func() any
+	once sync.Once
+}
+
+// Local per-P Pool appendix.
+type poolLocalInternal struct {
+	private any       // Can be used only by the respective P.
+	shared  poolChain // Local P can pushHead/popHead; any P can popTail.
+}
+
+type poolLocal struct {
+	poolLocalInternal
+
+	// Prevents false sharing on widespread platforms with
+	// 128 mod (cache line size) = 0 .
+	pad [128 - unsafe.Sizeof(poolLocalInternal{})%128]byte
+}
+
+// Put adds x to the pool.
+func (p *Pool) Put(x any) {
+	if x == nil {
+		return
+	}
+	l, _ := p.pin()
+	if l.private == nil {
+		l.private = x
+	} else {
+		l.shared.pushHead(x)
+	}
+}
+
+// Get selects an arbitrary item from the [Pool], removes it from the
+// Pool, and returns it to the caller.
+// Get may choose to ignore the pool and treat it as empty.
+// Callers should not assume any relation between values passed to [Pool.Put] and
+// the values returned by Get.
+//
+// If Get would otherwise return nil and p.New is non-nil, Get returns
+// the result of calling p.New.
+func (p *Pool) Get() any {
+	l, _ := p.pin()
+	x := l.private
+	l.private = nil
+	if x == nil {
+		x, _ = l.shared.popHead()
+		if x == nil {
+			x = p.getSlow(0)
+		}
+	}
+	if x == nil && p.New != nil {
+		x = p.New()
+	}
+	return x
+}
+
+// pin pins the current goroutine to P, disables preemption and
+// returns poolLocal pool for the P and the P's id.
+// Caller must call runtime_procUnpin() when done with the pool.
+func (p *Pool) pin() (*poolLocal, int) {
+	// Check whether p is nil to get a panic.
+	// Otherwise the nil dereference happens while the m is pinned,
+	// causing a fatal error rather than a panic.
+	if p == nil {
+		panic("nil Pool")
+	}
+
+	if ptr := atomic.LoadPointer(&p.local); ptr != nil {
+		handle := (*tls.Handle[*poolLocal])(ptr)
+		l := handle.Get()
+		if l == nil {
+			l = &poolLocal{}
+			handle.Set(l)
+		}
+		return l, 0
+	}
+
+	return p.pinSlow()
+}
+
+func (p *Pool) pinSlow() (*poolLocal, int) {
+	p.once.Do(func() {
+		handle := tls.Alloc[*poolLocal](func(head **poolLocal) {
+			if head != nil {
+				atomic.StorePointer(&p.victim, unsafe.Pointer(*head))
+			}
+		})
+		atomic.StorePointer(&p.local, unsafe.Pointer(&handle))
+	})
+	handle := (*tls.Handle[*poolLocal])(p.local)
+	l := &poolLocal{}
+	handle.Set(l)
+	return l, 0
+}
+
+func (p *Pool) getSlow(pid int) any {
+	if ptr := atomic.LoadPointer(&p.victim); ptr != nil {
+		l := (*poolLocal)(ptr)
+		if x := l.private; x != nil {
+			l.private = nil
+			return x
+		}
+		if x, _ := l.shared.popTail(); x != nil {
+			return x
+		}
+		atomic.StorePointer(&p.victim, nil)
+	}
+	return nil
+}
+
+// noCopy may be added to structs which must not be copied
+// after the first use.
+//
+// See https://golang.org/issues/8005#issuecomment-190753527
+// for details.
+//
+// Note that it must not be embedded, due to the Lock and Unlock methods.
+type noCopy struct{}
+
+// Lock is a no-op used by -copylocks checker from `go vet`.
+func (*noCopy) Lock()   {}
+func (*noCopy) Unlock() {}