From 068911e1dd7742939ae567d7bff30c9116c9c365 Mon Sep 17 00:00:00 2001 From: Keith Randall Date: Thu, 22 Oct 2020 13:11:16 -0700 Subject: [PATCH] [release-branch.go1.15] cmd/compile: fix storeType to handle pointers to go:notinheap types storeType splits compound stores up into a scalar parts and a pointer parts. The scalar part happens unconditionally, and the pointer part happens under the guard of a write barrier check. Types which are declared as pointers, but are represented as scalars because they might have "bad" values, were not handled correctly here. They ended up not getting stored in either set. Fixes #42151 Change-Id: I46f6600075c0c370e640b807066247237f93c7ac Reviewed-on: https://go-review.googlesource.com/c/go/+/264300 Trust: Keith Randall Reviewed-by: Ian Lance Taylor (cherry picked from commit 933721b8c7f981229974e2603850c2e9a7ffc5a1) Reviewed-on: https://go-review.googlesource.com/c/go/+/265719 Run-TryBot: Keith Randall TryBot-Result: Go Bot --- src/cmd/compile/internal/gc/ssa.go | 8 +++++++- test/fixedbugs/issue42032.go | 27 +++++++++++++++++++++++++++ 2 files changed, 34 insertions(+), 1 deletion(-) create mode 100644 test/fixedbugs/issue42032.go diff --git a/src/cmd/compile/internal/gc/ssa.go b/src/cmd/compile/internal/gc/ssa.go index 3e21450deb..7da04547c2 100644 --- a/src/cmd/compile/internal/gc/ssa.go +++ b/src/cmd/compile/internal/gc/ssa.go @@ -4976,7 +4976,10 @@ func (s *state) storeTypeScalars(t *types.Type, left, right *ssa.Value, skip ski case t.IsBoolean() || t.IsInteger() || t.IsFloat() || t.IsComplex(): s.store(t, left, right) case t.IsPtrShaped(): - // no scalar fields. + if t.IsPtr() && t.Elem().NotInHeap() { + s.store(t, left, right) // see issue 42032 + } + // otherwise, no scalar fields. case t.IsString(): if skip&skipLen != 0 { return @@ -5020,6 +5023,9 @@ func (s *state) storeTypeScalars(t *types.Type, left, right *ssa.Value, skip ski func (s *state) storeTypePtrs(t *types.Type, left, right *ssa.Value) { switch { case t.IsPtrShaped(): + if t.IsPtr() && t.Elem().NotInHeap() { + break // see issue 42032 + } s.store(t, left, right) case t.IsString(): ptr := s.newValue1(ssa.OpStringPtr, s.f.Config.Types.BytePtr, right) diff --git a/test/fixedbugs/issue42032.go b/test/fixedbugs/issue42032.go new file mode 100644 index 0000000000..c456b1db02 --- /dev/null +++ b/test/fixedbugs/issue42032.go @@ -0,0 +1,27 @@ +// run + +// Copyright 2020 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 + +//go:notinheap +type NIH struct { +} + +type T struct { + x *NIH + p *int +} + +var y NIH +var z int + +func main() { + a := []T{{&y, &z}} + a = append(a, T{&y, &z}) + if a[1].x == nil { + panic("pointer not written") + } +}