diff --git a/src/cmd/compile/internal/gc/obj.go b/src/cmd/compile/internal/gc/obj.go index 55a0ab7da7..474d718525 100644 --- a/src/cmd/compile/internal/gc/obj.go +++ b/src/cmd/compile/internal/gc/obj.go @@ -148,7 +148,7 @@ func dumpdata() { if reflectdata.ZeroSize > 0 { zero := base.PkgLinksym("go.map", "zero", obj.ABI0) objw.Global(zero, int32(reflectdata.ZeroSize), obj.DUPOK|obj.RODATA) - zero.Set(obj.AttrContentAddressable, true) + zero.Set(obj.AttrStatic, true) } staticdata.WriteFuncSyms() diff --git a/src/cmd/link/internal/loader/loader.go b/src/cmd/link/internal/loader/loader.go index efca824d98..9d5319c312 100644 --- a/src/cmd/link/internal/loader/loader.go +++ b/src/cmd/link/internal/loader/loader.go @@ -459,6 +459,15 @@ func (st *loadState) addSym(name string, ver int, r *oReader, li uint32, kind in if l.flags&FlagStrictDups != 0 { l.checkdup(name, r, li, oldi) } + // Fix for issue #47185 -- given two dupok symbols with + // different sizes, favor symbol with larger size. See + // also issue #46653. + szdup := l.SymSize(oldi) + sz := int64(r.Sym(li).Siz()) + if szdup < sz { + // new symbol overwrites old symbol. + l.objSyms[oldi] = objSym{r.objidx, li} + } return oldi } oldr, oldli := l.toLocal(oldi) diff --git a/test/fixedbugs/issue47185.dir/bad/bad.go b/test/fixedbugs/issue47185.dir/bad/bad.go new file mode 100644 index 0000000000..1aa4fbb909 --- /dev/null +++ b/test/fixedbugs/issue47185.dir/bad/bad.go @@ -0,0 +1,72 @@ +// 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. + +package a + +// Note that the use of CGO here is solely to trigger external +// linking, since that is required to trigger that bad behavior +// in this bug. + +// #include +import "C" + +func Bad() { + m := make(map[int64]A) + a := m[0] + if len(a.B.C1.D2.E2.F1) != 0 || + len(a.B.C1.D2.E2.F2) != 0 || + len(a.B.C1.D2.E2.F3) != 0 || + len(a.B.C1.D2.E2.F4) != 0 || + len(a.B.C1.D2.E2.F5) != 0 || + len(a.B.C1.D2.E2.F6) != 0 || + len(a.B.C1.D2.E2.F7) != 0 || + len(a.B.C1.D2.E2.F8) != 0 || + len(a.B.C1.D2.E2.F9) != 0 || + len(a.B.C1.D2.E2.F10) != 0 || + len(a.B.C1.D2.E2.F11) != 0 || + len(a.B.C1.D2.E2.F16) != 0 { + panic("bad") + } + C.malloc(100) +} + +type A struct { + B +} + +type B struct { + C1 C + C2 C +} + +type C struct { + D1 D + D2 D +} + +type D struct { + E1 E + E2 E + E3 E + E4 E +} + +type E struct { + F1 string + F2 string + F3 string + F4 string + F5 string + F6 string + F7 string + F8 string + F9 string + F10 string + F11 string + F12 string + F13 string + F14 string + F15 string + F16 string +} diff --git a/test/fixedbugs/issue47185.dir/main.go b/test/fixedbugs/issue47185.dir/main.go new file mode 100644 index 0000000000..7b46e55d8b --- /dev/null +++ b/test/fixedbugs/issue47185.dir/main.go @@ -0,0 +1,28 @@ +// 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. + +package main + +import ( + bad "issue47185.dir/bad" +) + +func main() { + another() + bad.Bad() +} + +func another() L { + m := make(map[string]L) + return m[""] +} + +type L struct { + A Data + B Data +} + +type Data struct { + F1 [22][]string +} diff --git a/test/fixedbugs/issue47185.go b/test/fixedbugs/issue47185.go new file mode 100644 index 0000000000..9c921b8698 --- /dev/null +++ b/test/fixedbugs/issue47185.go @@ -0,0 +1,11 @@ +// +build cgo +// runindir + +// 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. + +// Another test to verify compiler and linker handling of multiple +// competing map.zero symbol definitions. + +package ignored