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-rw-r--r--src/cmd/compile/internal/gc/subr.go6
-rw-r--r--src/cmd/compile/internal/gc/typecheck.go2
-rw-r--r--src/reflect/deepequal.go12
-rw-r--r--src/reflect/value.go12
-rw-r--r--src/runtime/netpoll.go47
-rw-r--r--test/fixedbugs/issue42076.go21
6 files changed, 81 insertions, 19 deletions
diff --git a/src/cmd/compile/internal/gc/subr.go b/src/cmd/compile/internal/gc/subr.go
index eccd6f8a74..defefd76b3 100644
--- a/src/cmd/compile/internal/gc/subr.go
+++ b/src/cmd/compile/internal/gc/subr.go
@@ -1854,8 +1854,10 @@ func isdirectiface(t *types.Type) bool {
}
switch t.Etype {
- case TPTR,
- TCHAN,
+ case TPTR:
+ // Pointers to notinheap types must be stored indirectly. See issue 42076.
+ return !t.Elem().NotInHeap()
+ case TCHAN,
TMAP,
TFUNC,
TUNSAFEPTR:
diff --git a/src/cmd/compile/internal/gc/typecheck.go b/src/cmd/compile/internal/gc/typecheck.go
index ce817db446..8ebeaf1330 100644
--- a/src/cmd/compile/internal/gc/typecheck.go
+++ b/src/cmd/compile/internal/gc/typecheck.go
@@ -2516,7 +2516,7 @@ func lookdot(n *Node, t *types.Type, dostrcmp int) *types.Field {
n.Left = nod(OADDR, n.Left, nil)
n.Left.SetImplicit(true)
n.Left = typecheck(n.Left, ctxType|ctxExpr)
- } else if tt.IsPtr() && !rcvr.IsPtr() && types.Identical(tt.Elem(), rcvr) {
+ } else if tt.IsPtr() && (!rcvr.IsPtr() || rcvr.IsPtr() && rcvr.Elem().NotInHeap()) && types.Identical(tt.Elem(), rcvr) {
n.Left = nod(ODEREF, n.Left, nil)
n.Left.SetImplicit(true)
n.Left = typecheck(n.Left, ctxType|ctxExpr)
diff --git a/src/reflect/deepequal.go b/src/reflect/deepequal.go
index be66464129..d951d8d999 100644
--- a/src/reflect/deepequal.go
+++ b/src/reflect/deepequal.go
@@ -35,7 +35,17 @@ func deepValueEqual(v1, v2 Value, visited map[visit]bool) bool {
// and it's safe and valid to get Value's internal pointer.
hard := func(v1, v2 Value) bool {
switch v1.Kind() {
- case Map, Slice, Ptr, Interface:
+ case Ptr:
+ if v1.typ.ptrdata == 0 {
+ // go:notinheap pointers can't be cyclic.
+ // At least, all of our current uses of go:notinheap have
+ // that property. The runtime ones aren't cyclic (and we don't use
+ // DeepEqual on them anyway), and the cgo-generated ones are
+ // all empty structs.
+ return false
+ }
+ fallthrough
+ case Map, Slice, Interface:
// Nil pointers cannot be cyclic. Avoid putting them in the visited map.
return !v1.IsNil() && !v2.IsNil()
}
diff --git a/src/reflect/value.go b/src/reflect/value.go
index bb6371b867..24eab6a2c6 100644
--- a/src/reflect/value.go
+++ b/src/reflect/value.go
@@ -90,6 +90,7 @@ func (f flag) ro() flag {
// pointer returns the underlying pointer represented by v.
// v.Kind() must be Ptr, Map, Chan, Func, or UnsafePointer
+// if v.Kind() == Ptr, the base type must not be go:notinheap.
func (v Value) pointer() unsafe.Pointer {
if v.typ.size != ptrSize || !v.typ.pointers() {
panic("can't call pointer on a non-pointer Value")
@@ -1453,7 +1454,16 @@ func (v Value) Pointer() uintptr {
// TODO: deprecate
k := v.kind()
switch k {
- case Chan, Map, Ptr, UnsafePointer:
+ case Ptr:
+ if v.typ.ptrdata == 0 {
+ // Handle pointers to go:notinheap types directly,
+ // so we never materialize such pointers as an
+ // unsafe.Pointer. (Such pointers are always indirect.)
+ // See issue 42076.
+ return *(*uintptr)(v.ptr)
+ }
+ fallthrough
+ case Chan, Map, UnsafePointer:
return uintptr(v.pointer())
case Func:
if v.flag&flagMethod != 0 {
diff --git a/src/runtime/netpoll.go b/src/runtime/netpoll.go
index 34ea82a7fa..77eb3aa4c6 100644
--- a/src/runtime/netpoll.go
+++ b/src/runtime/netpoll.go
@@ -79,16 +79,17 @@ type pollDesc struct {
lock mutex // protects the following fields
fd uintptr
closing bool
- everr bool // marks event scanning error happened
- user uint32 // user settable cookie
- rseq uintptr // protects from stale read timers
- rg uintptr // pdReady, pdWait, G waiting for read or nil
- rt timer // read deadline timer (set if rt.f != nil)
- rd int64 // read deadline
- wseq uintptr // protects from stale write timers
- wg uintptr // pdReady, pdWait, G waiting for write or nil
- wt timer // write deadline timer
- wd int64 // write deadline
+ everr bool // marks event scanning error happened
+ user uint32 // user settable cookie
+ rseq uintptr // protects from stale read timers
+ rg uintptr // pdReady, pdWait, G waiting for read or nil
+ rt timer // read deadline timer (set if rt.f != nil)
+ rd int64 // read deadline
+ wseq uintptr // protects from stale write timers
+ wg uintptr // pdReady, pdWait, G waiting for write or nil
+ wt timer // write deadline timer
+ wd int64 // write deadline
+ self *pollDesc // storage for indirect interface. See (*pollDesc).makeArg.
}
type pollCache struct {
@@ -157,6 +158,7 @@ func poll_runtime_pollOpen(fd uintptr) (*pollDesc, int) {
pd.wseq++
pd.wg = 0
pd.wd = 0
+ pd.self = pd
unlock(&pd.lock)
var errno int32
@@ -271,14 +273,14 @@ func poll_runtime_pollSetDeadline(pd *pollDesc, d int64, mode int) {
// Copy current seq into the timer arg.
// Timer func will check the seq against current descriptor seq,
// if they differ the descriptor was reused or timers were reset.
- pd.rt.arg = pd
+ pd.rt.arg = pd.makeArg()
pd.rt.seq = pd.rseq
resettimer(&pd.rt, pd.rd)
}
} else if pd.rd != rd0 || combo != combo0 {
pd.rseq++ // invalidate current timers
if pd.rd > 0 {
- modtimer(&pd.rt, pd.rd, 0, rtf, pd, pd.rseq)
+ modtimer(&pd.rt, pd.rd, 0, rtf, pd.makeArg(), pd.rseq)
} else {
deltimer(&pd.rt)
pd.rt.f = nil
@@ -287,14 +289,14 @@ func poll_runtime_pollSetDeadline(pd *pollDesc, d int64, mode int) {
if pd.wt.f == nil {
if pd.wd > 0 && !combo {
pd.wt.f = netpollWriteDeadline
- pd.wt.arg = pd
+ pd.wt.arg = pd.makeArg()
pd.wt.seq = pd.wseq
resettimer(&pd.wt, pd.wd)
}
} else if pd.wd != wd0 || combo != combo0 {
pd.wseq++ // invalidate current timers
if pd.wd > 0 && !combo {
- modtimer(&pd.wt, pd.wd, 0, netpollWriteDeadline, pd, pd.wseq)
+ modtimer(&pd.wt, pd.wd, 0, netpollWriteDeadline, pd.makeArg(), pd.wseq)
} else {
deltimer(&pd.wt)
pd.wt.f = nil
@@ -547,3 +549,20 @@ func (c *pollCache) alloc() *pollDesc {
unlock(&c.lock)
return pd
}
+
+// makeArg converts pd to an interface{}.
+// makeArg does not do any allocation. Normally, such
+// a conversion requires an allocation because pointers to
+// go:notinheap types (which pollDesc is) must be stored
+// in interfaces indirectly. See issue 42076.
+func (pd *pollDesc) makeArg() (i interface{}) {
+ x := (*eface)(unsafe.Pointer(&i))
+ x._type = pdType
+ x.data = unsafe.Pointer(&pd.self)
+ return
+}
+
+var (
+ pdEface interface{} = (*pollDesc)(nil)
+ pdType *_type = efaceOf(&pdEface)._type
+)
diff --git a/test/fixedbugs/issue42076.go b/test/fixedbugs/issue42076.go
new file mode 100644
index 0000000000..3e954813c9
--- /dev/null
+++ b/test/fixedbugs/issue42076.go
@@ -0,0 +1,21 @@
+// run
+
+// Copyright 2020 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 main
+
+import "reflect"
+
+//go:notinheap
+type NIH struct {
+}
+
+var x, y NIH
+
+func main() {
+ if reflect.DeepEqual(&x, &y) != true {
+ panic("should report true")
+ }
+}
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