mirror of
https://github.com/golang/go
synced 2024-11-08 19:26:14 -07:00
a0894ea5b5
Currently, escape analysis is able to record at most one dereference
when a parameter leaks to the heap; that is, at call sites, it can't
distinguish between any of these three functions:
func x1(p ****int) { sink = *p }
func x2(p ****int) { sink = **p }
func x3(p ****int) { sink = ***p }
Similarly, it's limited to recording parameter leaks to only the first
4 parameters, and only up to 6 dereferences.
All of these limitations are due to the awkward encoding scheme used
at the moment.
This CL replaces the encoding scheme with a simple [8]uint8 array,
which can handle up to the first 7 parameters, and up to 254
dereferences, which ought to be enough for anyone. And if not, it's
much more easily increased.
Shrinks export data size geometric mean for Kubernetes by 0.07%.
Fixes #33981.
Change-Id: I10a94b9accac9a0c91490e0d6d458316f5ca1e13
Reviewed-on: https://go-review.googlesource.com/c/go/+/197680
Reviewed-by: Cherry Zhang <cherryyz@google.com>
442 lines
9.1 KiB
Go
442 lines
9.1 KiB
Go
// errorcheck -0 -m -l
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// Copyright 2015 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Test escape analysis for function parameters.
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// In this test almost everything is BAD except the simplest cases
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// where input directly flows to output.
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package escape
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func zero() int { return 0 }
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var sink interface{}
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// in -> out
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func param0(p *int) *int { // ERROR "leaking param: p to result ~r1"
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return p
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}
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func caller0a() {
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i := 0
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_ = param0(&i)
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}
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func caller0b() {
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i := 0 // ERROR "moved to heap: i$"
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sink = param0(&i)
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}
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// in, in -> out, out
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func param1(p1, p2 *int) (*int, *int) { // ERROR "leaking param: p1 to result ~r2" "leaking param: p2 to result ~r3"
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return p1, p2
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}
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func caller1() {
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i := 0 // ERROR "moved to heap: i$"
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j := 0
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sink, _ = param1(&i, &j)
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}
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// in -> other in
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func param2(p1 *int, p2 **int) { // ERROR "leaking param: p1$" "p2 does not escape$"
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*p2 = p1
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}
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func caller2a() {
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i := 0 // ERROR "moved to heap: i$"
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var p *int
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param2(&i, &p)
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_ = p
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}
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func caller2b() {
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i := 0 // ERROR "moved to heap: i$"
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var p *int
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param2(&i, &p)
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sink = p
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}
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func paramArraySelfAssign(p *PairOfPairs) { // ERROR "p does not escape"
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p.pairs[0] = p.pairs[1] // ERROR "ignoring self-assignment in p.pairs\[0\] = p.pairs\[1\]"
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}
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func paramArraySelfAssignUnsafeIndex(p *PairOfPairs) { // ERROR "leaking param content: p"
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// Function call inside index disables self-assignment case to trigger.
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p.pairs[zero()] = p.pairs[1]
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p.pairs[zero()+1] = p.pairs[1]
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}
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type PairOfPairs struct {
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pairs [2]*Pair
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}
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type BoxedPair struct {
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pair *Pair
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}
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type WrappedPair struct {
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pair Pair
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}
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func leakParam(x interface{}) { // ERROR "leaking param: x"
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sink = x
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}
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func sinkAfterSelfAssignment1(box *BoxedPair) { // ERROR "leaking param content: box"
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box.pair.p1 = box.pair.p2 // ERROR "ignoring self-assignment in box.pair.p1 = box.pair.p2"
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sink = box.pair.p2
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}
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func sinkAfterSelfAssignment2(box *BoxedPair) { // ERROR "leaking param content: box"
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box.pair.p1 = box.pair.p2 // ERROR "ignoring self-assignment in box.pair.p1 = box.pair.p2"
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sink = box.pair
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}
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func sinkAfterSelfAssignment3(box *BoxedPair) { // ERROR "leaking param content: box"
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box.pair.p1 = box.pair.p2 // ERROR "ignoring self-assignment in box.pair.p1 = box.pair.p2"
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leakParam(box.pair.p2)
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}
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func sinkAfterSelfAssignment4(box *BoxedPair) { // ERROR "leaking param content: box"
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box.pair.p1 = box.pair.p2 // ERROR "ignoring self-assignment in box.pair.p1 = box.pair.p2"
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leakParam(box.pair)
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}
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func selfAssignmentAndUnrelated(box1, box2 *BoxedPair) { // ERROR "leaking param content: box2" "box1 does not escape"
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box1.pair.p1 = box1.pair.p2 // ERROR "ignoring self-assignment in box1.pair.p1 = box1.pair.p2"
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leakParam(box2.pair.p2)
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}
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func notSelfAssignment1(box1, box2 *BoxedPair) { // ERROR "leaking param content: box2" "box1 does not escape"
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box1.pair.p1 = box2.pair.p1
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}
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func notSelfAssignment2(p1, p2 *PairOfPairs) { // ERROR "leaking param content: p2" "p1 does not escape"
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p1.pairs[0] = p2.pairs[1]
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}
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func notSelfAssignment3(p1, p2 *PairOfPairs) { // ERROR "leaking param content: p2" "p1 does not escape"
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p1.pairs[0].p1 = p2.pairs[1].p1
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}
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func boxedPairSelfAssign(box *BoxedPair) { // ERROR "box does not escape"
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box.pair.p1 = box.pair.p2 // ERROR "ignoring self-assignment in box.pair.p1 = box.pair.p2"
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}
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func wrappedPairSelfAssign(w *WrappedPair) { // ERROR "w does not escape"
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w.pair.p1 = w.pair.p2 // ERROR "ignoring self-assignment in w.pair.p1 = w.pair.p2"
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}
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// in -> in
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type Pair struct {
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p1 *int
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p2 *int
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}
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func param3(p *Pair) { // ERROR "p does not escape"
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p.p1 = p.p2 // ERROR "param3 ignoring self-assignment in p.p1 = p.p2"
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}
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func caller3a() {
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i := 0
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j := 0
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p := Pair{&i, &j}
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param3(&p)
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_ = p
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}
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func caller3b() {
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i := 0 // ERROR "moved to heap: i$"
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j := 0 // ERROR "moved to heap: j$"
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p := Pair{&i, &j}
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param3(&p)
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sink = p // ERROR "p escapes to heap$"
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}
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// in -> rcvr
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func (p *Pair) param4(i *int) { // ERROR "p does not escape$" "leaking param: i$"
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p.p1 = i
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}
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func caller4a() {
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i := 0 // ERROR "moved to heap: i$"
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p := Pair{}
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p.param4(&i)
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_ = p
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}
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func caller4b() {
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i := 0 // ERROR "moved to heap: i$"
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p := Pair{}
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p.param4(&i)
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sink = p // ERROR "p escapes to heap$"
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}
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// in -> heap
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func param5(i *int) { // ERROR "leaking param: i$"
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sink = i
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}
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func caller5() {
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i := 0 // ERROR "moved to heap: i$"
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param5(&i)
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}
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// *in -> heap
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func param6(i ***int) { // ERROR "leaking param content: i$"
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sink = *i
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}
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func caller6a() {
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i := 0 // ERROR "moved to heap: i$"
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p := &i // ERROR "moved to heap: p$"
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p2 := &p
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param6(&p2)
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}
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// **in -> heap
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func param7(i ***int) { // ERROR "leaking param content: i$"
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sink = **i
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}
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func caller7() {
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i := 0 // ERROR "moved to heap: i$"
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p := &i
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p2 := &p
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param7(&p2)
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}
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// **in -> heap
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func param8(i **int) { // ERROR "i does not escape$"
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sink = **i // ERROR "\* \(\*i\) escapes to heap"
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}
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func caller8() {
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i := 0
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p := &i
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param8(&p)
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}
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// *in -> out
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func param9(p ***int) **int { // ERROR "leaking param: p to result ~r1 level=1"
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return *p
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}
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func caller9a() {
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i := 0
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p := &i
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p2 := &p
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_ = param9(&p2)
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}
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func caller9b() {
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i := 0 // ERROR "moved to heap: i$"
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p := &i // ERROR "moved to heap: p$"
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p2 := &p
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sink = param9(&p2)
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}
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// **in -> out
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func param10(p ***int) *int { // ERROR "leaking param: p to result ~r1 level=2"
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return **p
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}
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func caller10a() {
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i := 0
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p := &i
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p2 := &p
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_ = param10(&p2)
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}
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func caller10b() {
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i := 0 // ERROR "moved to heap: i$"
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p := &i
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p2 := &p
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sink = param10(&p2)
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}
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// in escapes to heap (address of param taken and returned)
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func param11(i **int) ***int { // ERROR "moved to heap: i$"
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return &i
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}
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func caller11a() {
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i := 0 // ERROR "moved to heap: i"
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p := &i // ERROR "moved to heap: p"
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_ = param11(&p)
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}
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func caller11b() {
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i := 0 // ERROR "moved to heap: i$"
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p := &i // ERROR "moved to heap: p$"
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sink = param11(&p)
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}
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func caller11c() { // GOOD
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i := 0 // ERROR "moved to heap: i$"
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p := &i // ERROR "moved to heap: p"
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sink = *param11(&p)
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}
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func caller11d() {
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i := 0 // ERROR "moved to heap: i$"
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p := &i // ERROR "moved to heap: p"
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p2 := &p
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sink = param11(p2)
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}
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// &in -> rcvr
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type Indir struct {
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p ***int
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}
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func (r *Indir) param12(i **int) { // ERROR "r does not escape$" "moved to heap: i$"
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r.p = &i
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}
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func caller12a() {
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i := 0 // ERROR "moved to heap: i$"
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p := &i // ERROR "moved to heap: p$"
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var r Indir
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r.param12(&p)
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_ = r
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}
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func caller12b() {
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i := 0 // ERROR "moved to heap: i$"
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p := &i // ERROR "moved to heap: p$"
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r := &Indir{} // ERROR "&Indir literal does not escape$"
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r.param12(&p)
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_ = r
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}
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func caller12c() {
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i := 0 // ERROR "moved to heap: i$"
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p := &i // ERROR "moved to heap: p$"
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r := Indir{}
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r.param12(&p)
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sink = r
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}
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func caller12d() {
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i := 0 // ERROR "moved to heap: i$"
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p := &i // ERROR "moved to heap: p$"
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r := Indir{}
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r.param12(&p)
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sink = **r.p
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}
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// in -> value rcvr
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type Val struct {
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p **int
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}
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func (v Val) param13(i *int) { // ERROR "v does not escape$" "leaking param: i$"
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*v.p = i
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}
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func caller13a() {
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i := 0 // ERROR "moved to heap: i$"
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var p *int
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var v Val
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v.p = &p
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v.param13(&i)
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_ = v
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}
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func caller13b() {
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i := 0 // ERROR "moved to heap: i$"
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var p *int
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v := Val{&p}
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v.param13(&i)
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_ = v
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}
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func caller13c() {
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i := 0 // ERROR "moved to heap: i$"
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var p *int
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v := &Val{&p} // ERROR "&Val literal does not escape$"
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v.param13(&i)
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_ = v
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}
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func caller13d() {
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i := 0 // ERROR "moved to heap: i$"
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var p *int // ERROR "moved to heap: p$"
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var v Val
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v.p = &p
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v.param13(&i)
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sink = v
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}
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func caller13e() {
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i := 0 // ERROR "moved to heap: i$"
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var p *int // ERROR "moved to heap: p$"
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v := Val{&p}
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v.param13(&i)
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sink = v
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}
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func caller13f() {
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i := 0 // ERROR "moved to heap: i$"
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var p *int // ERROR "moved to heap: p$"
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v := &Val{&p} // ERROR "&Val literal escapes to heap$"
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v.param13(&i)
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sink = v
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}
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func caller13g() {
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i := 0 // ERROR "moved to heap: i$"
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var p *int
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v := Val{&p}
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v.param13(&i)
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sink = *v.p
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}
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func caller13h() {
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i := 0 // ERROR "moved to heap: i$"
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var p *int
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v := &Val{&p} // ERROR "&Val literal does not escape$"
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v.param13(&i)
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sink = **v.p // ERROR "\* \(\*v\.p\) escapes to heap"
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}
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type Node struct {
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p *Node
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}
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var Sink *Node
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func f(x *Node) { // ERROR "leaking param content: x"
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Sink = &Node{x.p} // ERROR "&Node literal escapes to heap"
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}
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func g(x *Node) *Node { // ERROR "leaking param content: x"
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return &Node{x.p} // ERROR "&Node literal escapes to heap"
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}
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func h(x *Node) { // ERROR "leaking param: x"
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y := &Node{x} // ERROR "&Node literal does not escape"
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Sink = g(y)
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f(y)
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}
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// interface(in) -> out
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// See also issue 29353.
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// Convert to a non-direct interface, require an allocation and
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// copy x to heap (not to result).
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func param14a(x [4]*int) interface{} { // ERROR "leaking param: x$"
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return x // ERROR "x escapes to heap"
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}
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// Convert to a direct interface, does not need an allocation.
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// So x only leaks to result.
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func param14b(x *int) interface{} { // ERROR "leaking param: x to result ~r1 level=0"
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return x
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}
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