From 343b7fa6261a5b0ceaafed535438249ffa5686de Mon Sep 17 00:00:00 2001 From: Keith Randall Date: Thu, 13 Jun 2019 19:11:25 -0700 Subject: [PATCH] cmd/compile: don't mark argument array as noalg It ends up making two similar types, [N]uint8 of both alg and noalg varieties. Comparsions between the two then don't come out equal when they should. In particular, the type *[N]uint8 has an Elem pointer which must point to one of the above two types; it can't point to both. Thus allocating a *[N]uint8 and dereferencing it might be a different type than a [N]uint8. The fix is easy. Making a small test for this is really hard. It requires that both a argless defer and the test be imported by a common parent package. This is why a main binary doesn't see this issue, but a test does (as Agniva noticed), because there's a wrapper package that imports both the test and the defer. Types like [N]uint8 don't really need to be marked noalg anyway, as the generated code (if any) will be shared among all vanilla memory types of the same size. Fixes #32595 Change-Id: If7b77fa6ed56cd4495601c3f90170682d853b82f Reviewed-on: https://go-review.googlesource.com/c/go/+/182357 Run-TryBot: Keith Randall Reviewed-by: Emmanuel Odeke Reviewed-by: Cherry Zhang TryBot-Result: Gobot Gobot --- src/cmd/compile/internal/gc/reflect.go | 1 - test/fixedbugs/issue32595.dir/a.go | 9 +++++++++ test/fixedbugs/issue32595.dir/b.go | 15 +++++++++++++++ test/fixedbugs/issue32595.dir/main.go | 15 +++++++++++++++ test/fixedbugs/issue32595.go | 7 +++++++ 5 files changed, 46 insertions(+), 1 deletion(-) create mode 100644 test/fixedbugs/issue32595.dir/a.go create mode 100644 test/fixedbugs/issue32595.dir/b.go create mode 100644 test/fixedbugs/issue32595.dir/main.go create mode 100644 test/fixedbugs/issue32595.go diff --git a/src/cmd/compile/internal/gc/reflect.go b/src/cmd/compile/internal/gc/reflect.go index 0854817713..9b26ba16cb 100644 --- a/src/cmd/compile/internal/gc/reflect.go +++ b/src/cmd/compile/internal/gc/reflect.go @@ -330,7 +330,6 @@ func deferstruct(stksize int64) *types.Type { return f } argtype := types.NewArray(types.Types[TUINT8], stksize) - argtype.SetNoalg(true) argtype.Width = stksize argtype.Align = 1 // These fields must match the ones in runtime/runtime2.go:_defer and diff --git a/test/fixedbugs/issue32595.dir/a.go b/test/fixedbugs/issue32595.dir/a.go new file mode 100644 index 0000000000..8342dd5cbc --- /dev/null +++ b/test/fixedbugs/issue32595.dir/a.go @@ -0,0 +1,9 @@ +// Copyright 2019 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 + +func A() { + defer func() {}() +} diff --git a/test/fixedbugs/issue32595.dir/b.go b/test/fixedbugs/issue32595.dir/b.go new file mode 100644 index 0000000000..9a13a575a8 --- /dev/null +++ b/test/fixedbugs/issue32595.dir/b.go @@ -0,0 +1,15 @@ +// Copyright 2019 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 b + +import "reflect" + +func B() { + t1 := reflect.TypeOf([0]byte{}) + t2 := reflect.TypeOf(new([0]byte)).Elem() + if t1 != t2 { + panic("[0]byte types do not match") + } +} diff --git a/test/fixedbugs/issue32595.dir/main.go b/test/fixedbugs/issue32595.dir/main.go new file mode 100644 index 0000000000..20472cd72a --- /dev/null +++ b/test/fixedbugs/issue32595.dir/main.go @@ -0,0 +1,15 @@ +// Copyright 2019 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 ( + "a" + "b" +) + +func main() { + a.A() + b.B() +} diff --git a/test/fixedbugs/issue32595.go b/test/fixedbugs/issue32595.go new file mode 100644 index 0000000000..af6f134172 --- /dev/null +++ b/test/fixedbugs/issue32595.go @@ -0,0 +1,7 @@ +// rundir + +// Copyright 2019 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 ignored -- 2.48.1