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cmd/compile: fix crash when memmove argument is not the right type

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Make sure the argument to memmove is of pointer type before we try to
get the element type.

This has been noticed for code that uses unsafe+linkname so it can
call runtime.memmove. Probably not the best thing to allow, but the
code is out there and we'd rather not break it unnecessarily.

Fixes #30061

Change-Id: I334a8453f2e293959fd742044c43fbe93f0b3d31
Reviewed-on: https://go-review.googlesource.com/c/160826
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This commit is contained in:
Keith Randall 2019-02-01 15:27:53 -08:00 committed by Keith Randall
parent 7e987b7b33
commit 8f854244ad
3 changed files with 25 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
src/cmd/compile/internal/ssa/gen/generic.rules
View File

@ -1354,6 +1354,7 @@
// Inline small or disjoint runtime.memmove calls with constant length.
(StaticCall {sym} s1:(Store _ (Const(64|32) [sz]) s2:(Store _ src s3:(Store {t} _ dst mem))))
&& isSameSym(sym,"runtime.memmove")
&& t.(*types.Type).IsPtr() // avoids TUINTPTR, see issue 30061
&& s1.Uses == 1 && s2.Uses == 1 && s3.Uses == 1
&& isInlinableMemmove(dst,src,sz,config)
&& clobber(s1) && clobber(s2) && clobber(s3)

8
src/cmd/compile/internal/ssa/rewritegeneric.go
View File

@ -27397,7 +27397,7 @@ func rewriteValuegeneric_OpStaticCall_0(v *Value) bool {
config := b.Func.Config
_ = config
// match: (StaticCall {sym} s1:(Store _ (Const64 [sz]) s2:(Store _ src s3:(Store {t} _ dst mem))))
// cond: isSameSym(sym,"runtime.memmove") && s1.Uses == 1 && s2.Uses == 1 && s3.Uses == 1 && isInlinableMemmove(dst,src,sz,config) && clobber(s1) && clobber(s2) && clobber(s3)
// cond: isSameSym(sym,"runtime.memmove") && t.(*types.Type).IsPtr() && s1.Uses == 1 && s2.Uses == 1 && s3.Uses == 1 && isInlinableMemmove(dst,src,sz,config) && clobber(s1) && clobber(s2) && clobber(s3)
// result: (Move {t.(*types.Type).Elem()} [sz] dst src mem)
for {
sym := v.Aux
@ -27425,7 +27425,7 @@ func rewriteValuegeneric_OpStaticCall_0(v *Value) bool {
_ = s3.Args[2]
dst := s3.Args[1]
mem := s3.Args[2]
if !(isSameSym(sym, "runtime.memmove") && s1.Uses == 1 && s2.Uses == 1 && s3.Uses == 1 && isInlinableMemmove(dst, src, sz, config) && clobber(s1) && clobber(s2) && clobber(s3)) {
if !(isSameSym(sym, "runtime.memmove") && t.(*types.Type).IsPtr() && s1.Uses == 1 && s2.Uses == 1 && s3.Uses == 1 && isInlinableMemmove(dst, src, sz, config) && clobber(s1) && clobber(s2) && clobber(s3)) {
break
}
v.reset(OpMove)
@ -27437,7 +27437,7 @@ func rewriteValuegeneric_OpStaticCall_0(v *Value) bool {
return true
}
// match: (StaticCall {sym} s1:(Store _ (Const32 [sz]) s2:(Store _ src s3:(Store {t} _ dst mem))))
// cond: isSameSym(sym,"runtime.memmove") && s1.Uses == 1 && s2.Uses == 1 && s3.Uses == 1 && isInlinableMemmove(dst,src,sz,config) && clobber(s1) && clobber(s2) && clobber(s3)
// cond: isSameSym(sym,"runtime.memmove") && t.(*types.Type).IsPtr() && s1.Uses == 1 && s2.Uses == 1 && s3.Uses == 1 && isInlinableMemmove(dst,src,sz,config) && clobber(s1) && clobber(s2) && clobber(s3)
// result: (Move {t.(*types.Type).Elem()} [sz] dst src mem)
for {
sym := v.Aux
@ -27465,7 +27465,7 @@ func rewriteValuegeneric_OpStaticCall_0(v *Value) bool {
_ = s3.Args[2]
dst := s3.Args[1]
mem := s3.Args[2]
if !(isSameSym(sym, "runtime.memmove") && s1.Uses == 1 && s2.Uses == 1 && s3.Uses == 1 && isInlinableMemmove(dst, src, sz, config) && clobber(s1) && clobber(s2) && clobber(s3)) {
if !(isSameSym(sym, "runtime.memmove") && t.(*types.Type).IsPtr() && s1.Uses == 1 && s2.Uses == 1 && s3.Uses == 1 && isInlinableMemmove(dst, src, sz, config) && clobber(s1) && clobber(s2) && clobber(s3)) {
break
}
v.reset(OpMove)

20
test/fixedbugs/issue30061.go Normal file
View File

@ -0,0 +1,20 @@
// compile
// 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.
// Make sure we can linkname to memmove with an unsafe.Pointer argument.
package p
import "unsafe"
//go:linkname memmove runtime.memmove
func memmove(to, from unsafe.Pointer, n uintptr)
var V1, V2 int
func F() {
memmove(unsafe.Pointer(&V1), unsafe.Pointer(&V2), unsafe.Sizeof(int(0)))
}