cmd/gc: &x panics if x does

See golang.org/s/go12nil.

This CL is about getting all the right checks inserted.
A followup CL will add an optimization pass to
remove redundant checks.

R=ken2
CC=golang-dev
https://codereview.appspot.com/12970043

1 files changed, 128 insertions, 0 deletions

diff --git a/test/nilptr2.go b/test/nilptr2.go
new file mode 100644
index 000000000..3d9ca0a7a
--- /dev/null
+++ b/test/nilptr2.go
@@ -0,0 +1,128 @@
+// run
+
+// Copyright 2013 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
+
+func main() {
+	ok := true
+	for _, tt := range tests {
+		func() {
+			defer func() {
+				if err := recover(); err == nil {
+					println(tt.name, "did not panic")
+					ok = false
+				}
+			}()
+			tt.fn()
+		}()
+	}
+	if !ok {
+		println("BUG")
+	}
+}
+
+var intp *int
+var slicep *[]byte
+var a10p *[10]int
+var a10Mp *[1<<20]int
+var structp *Struct
+var bigstructp *BigStruct
+var i int
+var m *M
+var m1 *M1
+var m2 *M2
+
+func use(interface{}) {
+}
+
+var tests = []struct{
+	name string
+	fn func()
+}{
+	// Edit .+1,/^}/s/^[^	].+/	{"&", func() { println(&) }},\n	{"\&&", func() { println(\&&) }},/g
+	{"*intp", func() { println(*intp) }},
+	{"&*intp", func() { println(&*intp) }},
+	{"*slicep", func() { println(*slicep) }},
+	{"&*slicep", func() { println(&*slicep) }},
+	{"(*slicep)[0]", func() { println((*slicep)[0]) }},
+	{"&(*slicep)[0]", func() { println(&(*slicep)[0]) }},
+	{"(*slicep)[i]", func() { println((*slicep)[i]) }},
+	{"&(*slicep)[i]", func() { println(&(*slicep)[i]) }},
+	{"*a10p", func() { use(*a10p) }},
+	{"&*a10p", func() { println(&*a10p) }},
+	{"a10p[0]", func() { println(a10p[0]) }},
+	{"&a10p[0]", func() { println(&a10p[0]) }},
+	{"a10p[i]", func() { println(a10p[i]) }},
+	{"&a10p[i]", func() { println(&a10p[i]) }},
+	{"*structp", func() { use(*structp) }},
+	{"&*structp", func() { println(&*structp) }},
+	{"structp.i", func() { println(structp.i) }},
+	{"&structp.i", func() { println(&structp.i) }},
+	{"structp.j", func() { println(structp.j) }},
+	{"&structp.j", func() { println(&structp.j) }},
+	{"structp.k", func() { println(structp.k) }},
+	{"&structp.k", func() { println(&structp.k) }},
+	{"structp.x[0]", func() { println(structp.x[0]) }},
+	{"&structp.x[0]", func() { println(&structp.x[0]) }},
+	{"structp.x[i]", func() { println(structp.x[i]) }},
+	{"&structp.x[i]", func() { println(&structp.x[i]) }},
+	{"structp.x[9]", func() { println(structp.x[9]) }},
+	{"&structp.x[9]", func() { println(&structp.x[9]) }},
+	{"structp.l", func() { println(structp.l) }},
+	{"&structp.l", func() { println(&structp.l) }},
+	{"*bigstructp", func() { use(*bigstructp) }},
+	{"&*bigstructp", func() { println(&*bigstructp) }},
+	{"bigstructp.i", func() { println(bigstructp.i) }},
+	{"&bigstructp.i", func() { println(&bigstructp.i) }},
+	{"bigstructp.j", func() { println(bigstructp.j) }},
+	{"&bigstructp.j", func() { println(&bigstructp.j) }},
+	{"bigstructp.k", func() { println(bigstructp.k) }},
+	{"&bigstructp.k", func() { println(&bigstructp.k) }},
+	{"bigstructp.x[0]", func() { println(bigstructp.x[0]) }},
+	{"&bigstructp.x[0]", func() { println(&bigstructp.x[0]) }},
+	{"bigstructp.x[i]", func() { println(bigstructp.x[i]) }},
+	{"&bigstructp.x[i]", func() { println(&bigstructp.x[i]) }},
+	{"bigstructp.x[9]", func() { println(bigstructp.x[9]) }},
+	{"&bigstructp.x[9]", func() { println(&bigstructp.x[9]) }},
+	{"bigstructp.x[200<<20]", func() { println(bigstructp.x[200<<20]) }},
+	{"&bigstructp.x[200<<20]", func() { println(&bigstructp.x[200<<20]) }},
+	{"bigstructp.l", func() { println(bigstructp.l) }},
+	{"&bigstructp.l", func() { println(&bigstructp.l) }},
+	{"m1.F()", func() { println(m1.F()) }},
+	{"m1.M.F()", func() { println(m1.M.F()) }},
+	{"m2.F()", func() { println(m2.F()) }},
+	{"m2.M.F()", func() { println(m2.M.F()) }},
+}
+
+type Struct struct {
+	i int
+	j float64
+	k string
+	x [10]int
+	l []byte
+}
+
+type BigStruct struct {
+	i int
+	j float64
+	k string
+	x [256<<20]byte
+	l []byte
+}
+
+type M struct {
+}
+
+func (m *M) F() int {return 0}
+
+type M1 struct {
+	M
+}
+
+type M2 struct {
+	x int
+	M
+}