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

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>

diff --git a/src/cmd/compile/internal/ssa/gen/generic.rules b/src/cmd/compile/internal/ssa/gen/generic.rules
index 89fbfdc6bd76fe614ef8e0925880e929737c7df0..61451891a57e22edc44377beab8cf415d40267c4 100644 (file)
--- a/src/cmd/compile/internal/ssa/gen/generic.rules
+++ b/src/cmd/compile/internal/ssa/gen/generic.rules
@@ -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)

diff --git a/src/cmd/compile/internal/ssa/rewritegeneric.go b/src/cmd/compile/internal/ssa/rewritegeneric.go
index 79f0fd434aee2bb8cd5a00d6688fcbe03b8e0463..f2c7529e024f7dd226f4f825805d982063012d09 100644 (file)
--- a/src/cmd/compile/internal/ssa/rewritegeneric.go
+++ b/src/cmd/compile/internal/ssa/rewritegeneric.go
@@ -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)

diff --git a/test/fixedbugs/issue30061.go b/test/fixedbugs/issue30061.go
new file mode 100644 (file)
index 0000000..5092b01
--- /dev/null
+++ b/test/fixedbugs/issue30061.go
@@ -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)))
+}