still escaple pointer when only noescape exists.

Signed-off-by: doujiang24 <doujiang24@gmail.com>

src/cmd/cgo/internal/test/test.go

@@ -118,6 +118,7 @@ int add(int x, int y) {
 // escape vs noescape
 
 #cgo noescape handleGoStringPointerNoescape
+#cgo nocallback handleGoStringPointerNoescape
 void handleGoStringPointerNoescape(void *s) {}
 
 void handleGoStringPointerEscape(void *s) {}

src/cmd/cgo/out.go

@@ -644,11 +644,11 @@ func (p *Package) writeDefsFunc(fgo2 io.Writer, n *Name, callsMalloc *bool) {
 		fmt.Fprintf(fgo2, "\t_Cgo_no_callback(false)\n")
 	}
 
-	// use _Cgo_keepalive instead of _Cgo_use when noescape exist,
+	// use _Cgo_keepalive instead of _Cgo_use when noescape & nocallback exist,
 	// so that the compiler won't force to escape them to heap.
 	// instead, make the compiler keep them alive by using _Cgo_keepalive.
 	touchFunc := "_Cgo_use"
-	if p.noEscapes[n.C] {
+	if p.noEscapes[n.C] && p.noCallbacks[n.C] {
 		touchFunc = "_Cgo_keepalive"
 	}
 	fmt.Fprintf(fgo2, "\tif _Cgo_always_false {\n")

src/runtime/testdata/testprogcgo/cgonoescape.go

@@ -14,6 +14,7 @@ package main
 
 /*
 #cgo noescape runCWithNoEscape
+#cgo nocallback runCWithNoEscape
 
 void runCWithNoEscape(void *p) {
 }