cmd/compile: fix unsafeValue handles OLSH/ORSH wrong

For OLSH/ORSH, the right node is not a uintptr-typed. However,
unsafeValue still be called recursively for it, causing the
compiler crashes.

To fixing, the right node only needs to be evaluated
for side-effects, so just discard its value.

Fixes #32959

Change-Id: I34d5aa0823a0545f6dad1ec34774235ecf11addc
Reviewed-on: https://go-review.googlesource.com/c/go/+/185039
Run-TryBot: Cuong Manh Le <cuong.manhle.vn@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

diff --git a/src/cmd/compile/internal/gc/escape.go b/src/cmd/compile/internal/gc/escape.go
index 47ce853858e978eb0e25de97c46d0b3bb681dc9a..f92f4a7a6c22bb6259ff96464245674c9a72a3a5 100644 (file)
--- a/src/cmd/compile/internal/gc/escape.go
+++ b/src/cmd/compile/internal/gc/escape.go
@@ -614,9 +614,14 @@ func (e *Escape) unsafeValue(k EscHole, n *Node) {
                }
        case OPLUS, ONEG, OBITNOT:
                e.unsafeValue(k, n.Left)
-       case OADD, OSUB, OOR, OXOR, OMUL, ODIV, OMOD, OLSH, ORSH, OAND, OANDNOT:
+       case OADD, OSUB, OOR, OXOR, OMUL, ODIV, OMOD, OAND, OANDNOT:
                e.unsafeValue(k, n.Left)
                e.unsafeValue(k, n.Right)
+       case OLSH, ORSH:
+               e.unsafeValue(k, n.Left)
+               // RHS need not be uintptr-typed (#32959) and can't meaningfully
+               // flow pointers anyway.
+               e.discard(n.Right)
        default:
                e.exprSkipInit(e.discardHole(), n)
        }

diff --git a/test/fixedbugs/issue32959.go b/test/fixedbugs/issue32959.go
new file mode 100644 (file)
index 0000000..a0dc789
--- /dev/null
+++ b/test/fixedbugs/issue32959.go
@@ -0,0 +1,17 @@
+// 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.
+
+// Test escape analysis with shifting constant
+
+package main
+
+import "unsafe"
+
+func main() {
+       var l uint64
+       var p unsafe.Pointer
+       _ = unsafe.Pointer(uintptr(p) + (uintptr(l) >> 1))
+}