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go/test/escape_param.go
Matthew Dempsky a9831633be cmd/compile: update escape analysis tests for newescape 
The new escape analysis implementation tries to emit debugging
diagnostics that are compatible with the existing implementation, but
there's a handful of cases that are easier to handle by updating the
test expectations instead.

For regress tests that need updating, the original file is copied to
oldescapeXXX.go.go with -newescape=false added to the //errorcheck
line, while the file is updated in place with -newescape=true and new
test requirements.

Notable test changes:

1) escape_because.go looks for a lot of detailed internal debugging
messages that are fairly particular to how esc.go works and that I
haven't attempted to port over to escape.go yet.

2) There are a lot of "leaking param: x to result ~r1 level=-1"
messages for code like

    func(p *int) *T { return &T{p} }

that were simply wrong. Here &T must be heap allocated unconditionally
(because it's being returned); and since p is stored into it, p
escapes unconditionally too. esc.go incorrectly reports that p escapes
conditionally only if the returned pointer escaped.

3) esc.go used to print each "leaking param" analysis result as it
discovered them, which could lead to redundant messages (e.g., that a
param leaks at level=0 and level=1). escape.go instead prints
everything at the end, once it knows the shortest path to each sink.

4) esc.go didn't precisely model direct-interface types, resulting in
some values unnecessarily escaping to the heap when stored into
non-escaping interface values.

5) For functions written in assembly, esc.go only printed "does not
escape" messages, whereas escape.go prints "does not escape" or
"leaking param" as appropriate, consistent with the behavior for
functions written in Go.

6) 12 tests included "BAD" annotations identifying cases where esc.go
was unnecessarily heap allocating something. These are all fixed by
escape.go.

Updates #23109.

Change-Id: Iabc9eb14c94c9cadde3b183478d1fd54f013502f
Reviewed-on: https://go-review.googlesource.com/c/go/+/170447
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: David Chase <drchase@google.com>
2019-04-16 16:20:39 +00:00

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// errorcheck -0 -m -l -newescape=true
// 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 for function parameters.
// In this test almost everything is BAD except the simplest cases
// where input directly flows to output.
package escape
func zero() int { return 0 }
var sink interface{}
// in -> out
func param0(p *int) *int { // ERROR "leaking param: p to result ~r1"
return p
}
func caller0a() {
i := 0
_ = param0(&i)
}
func caller0b() {
i := 0 // ERROR "moved to heap: i$"
sink = param0(&i) // ERROR "param0\(&i\) escapes to heap"
}
// in, in -> out, out
func param1(p1, p2 *int) (*int, *int) { // ERROR "leaking param: p1 to result ~r2" "leaking param: p2 to result ~r3"
return p1, p2
}
func caller1() {
i := 0 // ERROR "moved to heap: i$"
j := 0
sink, _ = param1(&i, &j)
}
// in -> other in
func param2(p1 *int, p2 **int) { // ERROR "leaking param: p1$" "param2 p2 does not escape$"
*p2 = p1
}
func caller2a() {
i := 0 // ERROR "moved to heap: i$"
var p *int
param2(&i, &p)
_ = p
}
func caller2b() {
i := 0 // ERROR "moved to heap: i$"
var p *int
param2(&i, &p)
sink = p // ERROR "p escapes to heap$"
}
func paramArraySelfAssign(p *PairOfPairs) { // ERROR "p does not escape"
p.pairs[0] = p.pairs[1] // ERROR "ignoring self-assignment in p.pairs\[0\] = p.pairs\[1\]"
}
func paramArraySelfAssignUnsafeIndex(p *PairOfPairs) { // ERROR "leaking param content: p"
// Function call inside index disables self-assignment case to trigger.
p.pairs[zero()] = p.pairs[1]
p.pairs[zero()+1] = p.pairs[1]
}
type PairOfPairs struct {
pairs [2]*Pair
}
type BoxedPair struct {
pair *Pair
}
type WrappedPair struct {
pair Pair
}
func leakParam(x interface{}) { // ERROR "leaking param: x"
sink = x
}
func sinkAfterSelfAssignment1(box *BoxedPair) { // ERROR "leaking param content: box"
box.pair.p1 = box.pair.p2 // ERROR "ignoring self-assignment in box.pair.p1 = box.pair.p2"
sink = box.pair.p2 // ERROR "box.pair.p2 escapes to heap"
}
func sinkAfterSelfAssignment2(box *BoxedPair) { // ERROR "leaking param content: box"
box.pair.p1 = box.pair.p2 // ERROR "ignoring self-assignment in box.pair.p1 = box.pair.p2"
sink = box.pair // ERROR "box.pair escapes to heap"
}
func sinkAfterSelfAssignment3(box *BoxedPair) { // ERROR "leaking param content: box"
box.pair.p1 = box.pair.p2 // ERROR "ignoring self-assignment in box.pair.p1 = box.pair.p2"
leakParam(box.pair.p2) // ERROR "box.pair.p2 escapes to heap"
}
func sinkAfterSelfAssignment4(box *BoxedPair) { // ERROR "leaking param content: box"
box.pair.p1 = box.pair.p2 // ERROR "ignoring self-assignment in box.pair.p1 = box.pair.p2"
leakParam(box.pair) // ERROR "box.pair escapes to heap"
}
func selfAssignmentAndUnrelated(box1, box2 *BoxedPair) { // ERROR "leaking param content: box2" "box1 does not escape"
box1.pair.p1 = box1.pair.p2 // ERROR "ignoring self-assignment in box1.pair.p1 = box1.pair.p2"
leakParam(box2.pair.p2) // ERROR "box2.pair.p2 escapes to heap"
}
func notSelfAssignment1(box1, box2 *BoxedPair) { // ERROR "leaking param content: box2" "box1 does not escape"
box1.pair.p1 = box2.pair.p1
}
func notSelfAssignment2(p1, p2 *PairOfPairs) { // ERROR "leaking param content: p2" "p1 does not escape"
p1.pairs[0] = p2.pairs[1]
}
func notSelfAssignment3(p1, p2 *PairOfPairs) { // ERROR "leaking param content: p2" "p1 does not escape"
p1.pairs[0].p1 = p2.pairs[1].p1
}
func boxedPairSelfAssign(box *BoxedPair) { // ERROR "box does not escape"
box.pair.p1 = box.pair.p2 // ERROR "ignoring self-assignment in box.pair.p1 = box.pair.p2"
}
func wrappedPairSelfAssign(w *WrappedPair) { // ERROR "w does not escape"
w.pair.p1 = w.pair.p2 // ERROR "ignoring self-assignment in w.pair.p1 = w.pair.p2"
}
// in -> in
type Pair struct {
p1 *int
p2 *int
}
func param3(p *Pair) { // ERROR "param3 p does not escape"
p.p1 = p.p2 // ERROR "param3 ignoring self-assignment in p.p1 = p.p2"
}
func caller3a() {
i := 0
j := 0
p := Pair{&i, &j}
param3(&p)
_ = p
}
func caller3b() {
i := 0 // ERROR "moved to heap: i$"
j := 0 // ERROR "moved to heap: j$"
p := Pair{&i, &j}
param3(&p)
sink = p // ERROR "p escapes to heap$"
}
// in -> rcvr
func (p *Pair) param4(i *int) { // ERROR "\(\*Pair\).param4 p does not escape$" "leaking param: i$"
p.p1 = i
}
func caller4a() {
i := 0 // ERROR "moved to heap: i$"
p := Pair{}
p.param4(&i)
_ = p
}
func caller4b() {
i := 0 // ERROR "moved to heap: i$"
p := Pair{}
p.param4(&i)
sink = p // ERROR "p escapes to heap$"
}
// in -> heap
func param5(i *int) { // ERROR "leaking param: i$"
sink = i // ERROR "i escapes to heap$"
}
func caller5() {
i := 0 // ERROR "moved to heap: i$"
param5(&i)
}
// *in -> heap
func param6(i ***int) { // ERROR "leaking param content: i$"
sink = *i // ERROR "\*i escapes to heap$"
}
func caller6a() {
i := 0 // ERROR "moved to heap: i$"
p := &i // ERROR "moved to heap: p$"
p2 := &p
param6(&p2)
}
// **in -> heap
func param7(i ***int) { // ERROR "leaking param content: i$"
sink = **i // ERROR "\* \(\*i\) escapes to heap"
}
func caller7() {
i := 0 // ERROR "moved to heap: i$"
p := &i // ERROR "moved to heap: p$"
p2 := &p
param7(&p2)
}
// **in -> heap
func param8(i **int) { // ERROR "param8 i does not escape$"
sink = **i // ERROR "\* \(\*i\) escapes to heap"
}
func caller8() {
i := 0
p := &i
param8(&p)
}
// *in -> out
func param9(p ***int) **int { // ERROR "leaking param: p to result ~r1 level=1"
return *p
}
func caller9a() {
i := 0
p := &i
p2 := &p
_ = param9(&p2)
}
func caller9b() {
i := 0 // ERROR "moved to heap: i$"
p := &i // ERROR "moved to heap: p$"
p2 := &p
sink = param9(&p2) // ERROR "param9\(&p2\) escapes to heap"
}
// **in -> out
func param10(p ***int) *int { // ERROR "leaking param: p to result ~r1 level=2"
return **p
}
func caller10a() {
i := 0
p := &i
p2 := &p
_ = param10(&p2)
}
func caller10b() {
i := 0 // ERROR "moved to heap: i$"
p := &i
p2 := &p
sink = param10(&p2) // ERROR "param10\(&p2\) escapes to heap"
}
// in escapes to heap (address of param taken and returned)
func param11(i **int) ***int { // ERROR "moved to heap: i$"
return &i
}
func caller11a() {
i := 0 // ERROR "moved to heap: i"
p := &i // ERROR "moved to heap: p"
_ = param11(&p)
}
func caller11b() {
i := 0 // ERROR "moved to heap: i$"
p := &i // ERROR "moved to heap: p$"
sink = param11(&p) // ERROR "param11\(&p\) escapes to heap"
}
func caller11c() { // GOOD
i := 0 // ERROR "moved to heap: i$"
p := &i // ERROR "moved to heap: p"
sink = *param11(&p) // ERROR "\*param11\(&p\) escapes to heap"
}
func caller11d() {
i := 0 // ERROR "moved to heap: i$"
p := &i // ERROR "moved to heap: p"
p2 := &p
sink = param11(p2) // ERROR "param11\(p2\) escapes to heap"
}
// &in -> rcvr
type Indir struct {
p ***int
}
func (r *Indir) param12(i **int) { // ERROR "\(\*Indir\).param12 r does not escape$" "moved to heap: i$"
r.p = &i
}
func caller12a() {
i := 0 // ERROR "moved to heap: i$"
p := &i // ERROR "moved to heap: p$"
var r Indir
r.param12(&p)
_ = r
}
func caller12b() {
i := 0 // ERROR "moved to heap: i$"
p := &i // ERROR "moved to heap: p$"
r := &Indir{} // ERROR "caller12b &Indir literal does not escape$"
r.param12(&p)
_ = r
}
func caller12c() {
i := 0 // ERROR "moved to heap: i$"
p := &i // ERROR "moved to heap: p$"
r := Indir{}
r.param12(&p)
sink = r // ERROR "r escapes to heap$"
}
func caller12d() {
i := 0 // ERROR "moved to heap: i$"
p := &i // ERROR "moved to heap: p$"
r := Indir{}
r.param12(&p)
sink = **r.p // ERROR "\* \(\*r\.p\) escapes to heap"
}
// in -> value rcvr
type Val struct {
p **int
}
func (v Val) param13(i *int) { // ERROR "Val.param13 v does not escape$" "leaking param: i$"
*v.p = i
}
func caller13a() {
i := 0 // ERROR "moved to heap: i$"
var p *int
var v Val
v.p = &p
v.param13(&i)
_ = v
}
func caller13b() {
i := 0 // ERROR "moved to heap: i$"
var p *int
v := Val{&p}
v.param13(&i)
_ = v
}
func caller13c() {
i := 0 // ERROR "moved to heap: i$"
var p *int
v := &Val{&p} // ERROR "caller13c &Val literal does not escape$"
v.param13(&i)
_ = v
}
func caller13d() {
i := 0 // ERROR "moved to heap: i$"
var p *int // ERROR "moved to heap: p$"
var v Val
v.p = &p
v.param13(&i)
sink = v // ERROR "v escapes to heap$"
}
func caller13e() {
i := 0 // ERROR "moved to heap: i$"
var p *int // ERROR "moved to heap: p$"
v := Val{&p}
v.param13(&i)
sink = v // ERROR "v escapes to heap$"
}
func caller13f() {
i := 0 // ERROR "moved to heap: i$"
var p *int // ERROR "moved to heap: p$"
v := &Val{&p} // ERROR "&Val literal escapes to heap$"
v.param13(&i)
sink = v // ERROR "v escapes to heap$"
}
func caller13g() {
i := 0 // ERROR "moved to heap: i$"
var p *int
v := Val{&p}
v.param13(&i)
sink = *v.p // ERROR "\*v\.p escapes to heap"
}
func caller13h() {
i := 0 // ERROR "moved to heap: i$"
var p *int
v := &Val{&p} // ERROR "caller13h &Val literal does not escape$"
v.param13(&i)
sink = **v.p // ERROR "\* \(\*v\.p\) escapes to heap"
}
type Node struct {
p *Node
}
var Sink *Node
func f(x *Node) { // ERROR "leaking param content: x"
Sink = &Node{x.p} // ERROR "&Node literal escapes to heap"
}
func g(x *Node) *Node { // ERROR "leaking param content: x"
return &Node{x.p} // ERROR "&Node literal escapes to heap"
}
func h(x *Node) { // ERROR "leaking param: x"
y := &Node{x} // ERROR "h &Node literal does not escape"
Sink = g(y)
f(y)
}
// interface(in) -> out
// See also issue 29353.
// Convert to a non-direct interface, require an allocation and
// copy x to heap (not to result).
func param14a(x [4]*int) interface{} { // ERROR "leaking param: x$"
return x // ERROR "x escapes to heap"
}
// Convert to a direct interface, does not need an allocation.
// So x only leaks to result.
func param14b(x *int) interface{} { // ERROR "leaking param: x to result ~r1 level=0"
return x // ERROR "x escapes to heap"
}
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