diff --git a/src/cmd/compile/internal/gc/escape.go b/src/cmd/compile/internal/gc/escape.go index 79df584ab1..93965d4fac 100644 --- a/src/cmd/compile/internal/gc/escape.go +++ b/src/cmd/compile/internal/gc/escape.go @@ -771,10 +771,11 @@ func (e *Escape) call(ks []EscHole, call, where *Node) { var fn *Node switch call.Op { case OCALLFUNC: - if call.Left.Op == ONAME && call.Left.Class() == PFUNC { - fn = call.Left - } else if call.Left.Op == OCLOSURE { - fn = call.Left.Func.Closure.Func.Nname + switch v := staticValue(call.Left); { + case v.Op == ONAME && v.Class() == PFUNC: + fn = v + case v.Op == OCLOSURE: + fn = v.Func.Closure.Func.Nname } case OCALLMETH: fn = asNode(call.Left.Type.FuncType().Nname) diff --git a/src/cmd/compile/internal/gc/inl.go b/src/cmd/compile/internal/gc/inl.go index 5740864b12..cac51685df 100644 --- a/src/cmd/compile/internal/gc/inl.go +++ b/src/cmd/compile/internal/gc/inl.go @@ -751,6 +751,55 @@ func inlinableClosure(n *Node) *Node { return f } +func staticValue(n *Node) *Node { + for { + n1 := staticValue1(n) + if n1 == nil { + return n + } + n = n1 + } +} + +// staticValue1 implements a simple SSA-like optimization. +func staticValue1(n *Node) *Node { + if n.Op != ONAME || n.Class() != PAUTO || n.Name.Addrtaken() { + return nil + } + + defn := n.Name.Defn + if defn == nil { + return nil + } + + var rhs *Node +FindRHS: + switch defn.Op { + case OAS: + rhs = defn.Right + case OAS2: + for i, lhs := range defn.List.Slice() { + if lhs == n { + rhs = defn.Rlist.Index(i) + break FindRHS + } + } + Fatalf("%v missing from LHS of %v", n, defn) + default: + return nil + } + if rhs == nil { + Fatalf("RHS is nil: %v", defn) + } + + unsafe, _ := reassigned(n) + if unsafe { + return nil + } + + return rhs +} + // reassigned takes an ONAME node, walks the function in which it is defined, and returns a boolean // indicating whether the name has any assignments other than its declaration. // The second return value is the first such assignment encountered in the walk, if any. It is mostly diff --git a/test/escape_closure.go b/test/escape_closure.go index 3b14027fa4..9152319fe0 100644 --- a/test/escape_closure.go +++ b/test/escape_closure.go @@ -50,7 +50,7 @@ func ClosureCallArgs4() { } func ClosureCallArgs5() { - x := 0 // ERROR "moved to heap: x" + x := 0 // ERROR "moved to heap: x" // TODO(mdempsky): We get "leaking param: p" here because the new escape analysis pass // can tell that p flows directly to sink, but it's a little weird. Re-evaluate. sink = func(p *int) *int { // ERROR "leaking param: p" "func literal does not escape" @@ -132,7 +132,7 @@ func ClosureCallArgs14() { } func ClosureCallArgs15() { - x := 0 // ERROR "moved to heap: x" + x := 0 // ERROR "moved to heap: x" p := &x sink = func(p **int) *int { // ERROR "leaking param content: p" "func literal does not escape" return *p @@ -164,3 +164,16 @@ func ClosureLeak2a(a ...string) string { // ERROR "leaking param content: a" func ClosureLeak2b(f func() string) string { // ERROR "f does not escape" return f() } + +func ClosureIndirect() { + f := func(p *int) {} // ERROR "p does not escape" "func literal does not escape" + f(new(int)) // ERROR "new\(int\) does not escape" + + g := f + g(new(int)) // ERROR "new\(int\) does not escape" + + h := nopFunc + h(new(int)) // ERROR "new\(int\) does not escape" +} + +func nopFunc(p *int) {} // ERROR "p does not escape"