diff --git a/src/cmd/compile/internal/gc/walk.go b/src/cmd/compile/internal/gc/walk.go index 2133a160b2..98ebb23991 100644 --- a/src/cmd/compile/internal/gc/walk.go +++ b/src/cmd/compile/internal/gc/walk.go @@ -550,8 +550,12 @@ opswitch: case OCLOSUREVAR, OCFUNC: case OCALLINTER, OCALLFUNC, OCALLMETH: - if n.Op == OCALLINTER { + if n.Op == OCALLINTER || n.Op == OCALLMETH { + // We expect both interface call reflect.Type.Method and concrete + // call reflect.(*rtype).Method. usemethod(n) + } + if n.Op == OCALLINTER { markUsedIfaceMethod(n) } @@ -3710,6 +3714,16 @@ func usemethod(n *Node) { } } + // Don't mark reflect.(*rtype).Method, etc. themselves in the reflect package. + // Those functions may be alive via the itab, which should not cause all methods + // alive. We only want to mark their callers. + if myimportpath == "reflect" { + switch Curfn.Func.Nname.Sym.Name { // TODO: is there a better way than hardcoding the names? + case "(*rtype).Method", "(*rtype).MethodByName", "(*interfaceType).Method", "(*interfaceType).MethodByName": + return + } + } + // Note: Don't rely on res0.Type.String() since its formatting depends on multiple factors // (including global variables such as numImports - was issue #19028). // Also need to check for reflect package itself (see Issue #38515). diff --git a/test/reflectmethod7.go b/test/reflectmethod7.go new file mode 100644 index 0000000000..42429978b4 --- /dev/null +++ b/test/reflectmethod7.go @@ -0,0 +1,24 @@ +// run + +// Copyright 2021 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. + +// See issue 44207. + +package main + +import "reflect" + +type S int + +func (s S) M() {} + +func main() { + t := reflect.TypeOf(S(0)) + fn, ok := reflect.PtrTo(t).MethodByName("M") + if !ok { + panic("FAIL") + } + fn.Func.Call([]reflect.Value{reflect.New(t)}) +}