cmd/gc: fix crash during escape analysis

Fixes #10441

Compiler crashed as:

panic: runtime error: invalid memory address or nil pointer dereference
goroutine 1 [running]:
cmd/internal/gc.haspointers(0x0, 0xffffffffffffffff)
    src/cmd/internal/gc/reflect.go:623 +0x1f
cmd/internal/gc.escwalk(0x20c82dc00, 0xffffffffffffffff, 0x20c82dda0, 0x20c835520)
    src/cmd/internal/gc/esc.go:1291 +0x14aa
cmd/internal/gc.escwalk(0x20c82dc00, 0xffffffffffffffff, 0x20c82dda0, 0x20beac340)
    src/cmd/internal/gc/esc.go:1386 +0x836

while evaluating haspointers of the fake OADDR node here:

	leaks = level <= 0 && dst.Escloopdepth < src.Escloopdepth || level < 0 && dst == &e.funcParam && haspointers(src.Type)

Change-Id: I13c23fced52e8fcd0ae1df81b374df8632eb7790
Reviewed-on: https://go-review.googlesource.com/8932
Reviewed-by: David Chase <drchase@google.com>
Run-TryBot: Dmitry Vyukov <dvyukov@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>

diff --git a/src/cmd/internal/gc/esc.go b/src/cmd/internal/gc/esc.go
index 6f894c9165ba8d60dd14d8389289e501f3bea3bb..0ca407a734741ffd7030b7da158924af12b96af7 100644 (file)
--- a/src/cmd/internal/gc/esc.go
+++ b/src/cmd/internal/gc/esc.go
@@ -885,6 +885,7 @@ func escassign(e *EscState, dst *Node, src *Node) {
                a := Nod(OADDR, src, nil)
                a.Lineno = src.Lineno
                a.Escloopdepth = src.Escloopdepth
+               a.Type = Ptrto(src.Type)
                escflows(e, dst, a)
 
                // Flowing multiple returns to a single dst happens when

diff --git a/test/fixedbugs/issue10441.go b/test/fixedbugs/issue10441.go
new file mode 100644 (file)
index 0000000..25832fa
--- /dev/null
+++ b/test/fixedbugs/issue10441.go
@@ -0,0 +1,17 @@
+// build
+
+// Copyright 2015 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 p
+
+func bar() {
+       f := func() {}
+       foo(&f)
+}
+
+func foo(f *func()) func() {
+       defer func() {}() // prevent inlining of foo
+       return *f
+}