test: add tests for escape analysis when assigning to indirections

False positives (var incorrectly escapes) are marked with BAD.

Change-Id: I0114d87ee467fe1e3b27642f8c5a04d4a9664211
Reviewed-on: https://go-review.googlesource.com/5295
Reviewed-by: Keith Randall <khr@golang.org>

1 files changed, 153 insertions, 0 deletions

diff --git a/test/escape_indir.go b/test/escape_indir.go
new file mode 100644
index 0000000000..91aac77d73
--- /dev/null
+++ b/test/escape_indir.go
@@ -0,0 +1,153 @@
+// errorcheck -0 -m -l
+
+// 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.
+
+// Test escape analysis when assigning to indirections.
+
+package escape
+
+var sink interface{}
+
+type ConstPtr struct {
+	p *int
+	c ConstPtr2
+	x **ConstPtr
+}
+
+type ConstPtr2 struct {
+	p *int
+	i int
+}
+
+func constptr0() {
+	i := 0           // ERROR "moved to heap: i"
+	x := &ConstPtr{} // ERROR "&ConstPtr literal does not escape"
+	// BAD: i should not escape here
+	x.p = &i // ERROR "&i escapes to heap"
+	_ = x
+}
+
+func constptr01() *ConstPtr {
+	i := 0           // ERROR "moved to heap: i"
+	x := &ConstPtr{} // ERROR "&ConstPtr literal escapes to heap"
+	x.p = &i         // ERROR "&i escapes to heap"
+	return x
+}
+
+func constptr02() ConstPtr {
+	i := 0           // ERROR "moved to heap: i"
+	x := &ConstPtr{} // ERROR "&ConstPtr literal does not escape"
+	x.p = &i         // ERROR "&i escapes to heap"
+	return *x
+}
+
+func constptr03() **ConstPtr {
+	i := 0           // ERROR "moved to heap: i"
+	x := &ConstPtr{} // ERROR "&ConstPtr literal escapes to heap" "moved to heap: x"
+	x.p = &i         // ERROR "&i escapes to heap"
+	return &x        // ERROR "&x escapes to heap"
+}
+
+func constptr1() {
+	i := 0           // ERROR "moved to heap: i"
+	x := &ConstPtr{} // ERROR "&ConstPtr literal escapes to heap"
+	x.p = &i         // ERROR "&i escapes to heap"
+	sink = x
+}
+
+func constptr2() {
+	i := 0           // ERROR "moved to heap: i"
+	x := &ConstPtr{} // ERROR "&ConstPtr literal does not escape"
+	x.p = &i         // ERROR "&i escapes to heap"
+	sink = *x
+}
+
+func constptr4() *ConstPtr {
+	p := new(ConstPtr) // ERROR "new\(ConstPtr\) escapes to heap"
+	*p = *&ConstPtr{}  // ERROR "&ConstPtr literal does not escape"
+	return p
+}
+
+func constptr5() *ConstPtr {
+	p := new(ConstPtr) // ERROR "new\(ConstPtr\) escapes to heap"
+	p1 := &ConstPtr{}  // ERROR "&ConstPtr literal does not escape"
+	*p = *p1
+	return p
+}
+
+// BAD: p should not escape here
+func constptr6(p *ConstPtr) { // ERROR "leaking param: p"
+	p1 := &ConstPtr{} // ERROR "&ConstPtr literal does not escape"
+	*p1 = *p
+	_ = p1
+}
+
+func constptr7() **ConstPtr {
+	p := new(ConstPtr) // ERROR "new\(ConstPtr\) escapes to heap" "moved to heap: p"
+	var tmp ConstPtr2
+	p1 := &tmp // ERROR "&tmp does not escape"
+	p.c = *p1
+	return &p // ERROR "&p escapes to heap"
+}
+
+func constptr8() *ConstPtr {
+	p := new(ConstPtr) // ERROR "new\(ConstPtr\) escapes to heap"
+	var tmp ConstPtr2
+	p.c = *&tmp // ERROR "&tmp does not escape"
+	return p
+}
+
+func constptr9() ConstPtr {
+	p := new(ConstPtr) // ERROR "new\(ConstPtr\) does not escape"
+	var p1 ConstPtr2
+	i := 0    // ERROR "moved to heap: i"
+	p1.p = &i // ERROR "&i escapes to heap"
+	p.c = p1
+	return *p
+}
+
+func constptr10() ConstPtr {
+	x := &ConstPtr{} // ERROR "moved to heap: x" "&ConstPtr literal escapes to heap"
+	i := 0           // ERROR "moved to heap: i"
+	var p *ConstPtr
+	p = &ConstPtr{p: &i, x: &x} // ERROR "&i escapes to heap" "&x escapes to heap" "&ConstPtr literal does not escape"
+	var pp **ConstPtr
+	pp = &p // ERROR "&p does not escape"
+	return **pp
+}
+
+func constptr11() *ConstPtr {
+	i := 0             // ERROR "moved to heap: i"
+	p := new(ConstPtr) // ERROR "new\(ConstPtr\) escapes to heap"
+	p1 := &ConstPtr{}  // ERROR "&ConstPtr literal does not escape"
+	p1.p = &i          // ERROR "&i escapes to heap"
+	*p = *p1
+	return p
+}
+
+func foo(p **int) { // ERROR "foo p does not escape"
+	i := 0 // ERROR "moved to heap: i"
+	y := p
+	*y = &i // ERROR "&i escapes to heap"
+}
+
+func foo1(p *int) { // ERROR "p does not escape"
+	i := 0  // ERROR "moved to heap: i"
+	y := &p // ERROR "&p does not escape"
+	*y = &i // ERROR "&i escapes to heap"
+}
+
+func foo2() {
+	type Z struct {
+		f **int
+	}
+	x := new(int) // ERROR "moved to heap: x" "new\(int\) escapes to heap"
+	sink = &x     // ERROR "&x escapes to heap"
+	var z Z
+	z.f = &x // ERROR "&x does not escape"
+	p := z.f
+	i := 0  // ERROR "moved to heap: i"
+	*p = &i // ERROR "&i escapes to heap"
+}