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go/test/closure3.dir/main.go
David Chase cc258e6785 cmd/compile: add "deadlocals" pass to remove unused locals
This CL adds a "deadlocals" pass, which runs after inlining and before
escape analysis, to prune any unneeded local variables and
assignments. In particular, this helps avoid unnecessary Addrtaken
markings from unreachable closures.

Deadlocals is sensitive to "_ = ..." as a signal of explicit
use for testing.  This signal occurs only if the entire
left-hand-side is "_" targets; if it is
  `_, ok := someInlinedFunc(args)`
then the first return value is eligible for dead code elimination.

Use this (`_ = x`) to fix tests broken by deadlocals elimination.

Includes a test, based on one of the tests that required modification.

Matthew Dempsky wrote this, changing ownership to allow rebases, commits, tweaks.

Fixes #65158.

Old-Change-Id: I723fb69ccd7baadaae04d415702ce6c8901eaf4e
Change-Id: I1f25f4293b19527f305c18c3680b214237a7714c
Reviewed-on: https://go-review.googlesource.com/c/go/+/600498
Reviewed-by: Keith Randall <khr@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Keith Randall <khr@golang.org>
Auto-Submit: David Chase <drchase@google.com>
Commit-Queue: David Chase <drchase@google.com>
2024-07-30 15:46:27 +00:00

317 lines
9.2 KiB
Go

// Copyright 2017 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.
// Check correctness of various closure corner cases
// that are expected to be inlined
package main
var ok bool
var sink int
func main() {
{
if x := func() int { // ERROR "can inline main.func1"
return 1
}(); x != 1 { // ERROR "inlining call to main.func1"
ppanic("x != 1")
}
if x := func() int { // ERROR "can inline main.func2" "func literal does not escape"
return 1
}; x() != 1 { // ERROR "inlining call to main.func2"
_ = x // prevent simple deadcode elimination after inlining
ppanic("x() != 1")
}
}
{
if y := func(x int) int { // ERROR "can inline main.func3"
return x + 2
}(40); y != 42 { // ERROR "inlining call to main.func3"
ppanic("y != 42")
}
if y := func(x int) int { // ERROR "can inline main.func4" "func literal does not escape"
return x + 2
}; y(40) != 42 { // ERROR "inlining call to main.func4"
_ = y // prevent simple deadcode elimination after inlining
ppanic("y(40) != 42")
}
}
{
y := func(x int) int { // ERROR "can inline main.func5" "func literal does not escape"
return x + 2
}
y = func(x int) int { // ERROR "can inline main.func6" "func literal does not escape"
return x + 1
}
if y(40) != 41 {
ppanic("y(40) != 41")
}
}
{
func() { // ERROR "func literal does not escape"
y := func(x int) int { // ERROR "can inline main.func7.1" "func literal does not escape"
return x + 2
}
y = func(x int) int { // ERROR "can inline main.func7.2" "func literal does not escape"
return x + 1
}
if y(40) != 41 {
ppanic("y(40) != 41")
}
}()
}
{
y := func(x int) int { // ERROR "can inline main.func8" "func literal does not escape"
return x + 2
}
y, sink = func(x int) int { // ERROR "can inline main.func9" "func literal does not escape"
return x + 1
}, 42
if y(40) != 41 {
ppanic("y(40) != 41")
}
}
{
func() { // ERROR "func literal does not escape"
y := func(x int) int { // ERROR "can inline main.func10.1" "func literal does not escape"
return x + 2
}
y, sink = func(x int) int { // ERROR "can inline main.func10.2" "func literal does not escape"
return x + 1
}, 42
if y(40) != 41 {
ppanic("y(40) != 41")
}
}()
}
{
y := func(x int) int { // ERROR "can inline main.func11" "func literal does not escape"
return x + 2
}
y, sink = func() (func(int) int, int) { // ERROR "can inline main.func12"
return func(x int) int { // ERROR "can inline main.func12" "func literal escapes to heap"
return x + 1
}, 42
}() // ERROR "func literal does not escape" "inlining call to main.func12"
if y(40) != 41 {
ppanic("y(40) != 41")
}
}
{
func() { // ERROR "func literal does not escape"
y := func(x int) int { // ERROR "func literal does not escape" "can inline main.func13.1"
return x + 2
}
y, sink = func() (func(int) int, int) { // ERROR "can inline main.func13.2"
return func(x int) int { // ERROR "can inline main.func13.2" "func literal escapes to heap"
return x + 1
}, 42
}() // ERROR "func literal does not escape" "inlining call to main.func13.2"
if y(40) != 41 {
ppanic("y(40) != 41")
}
}()
}
{
y := func(x int) int { // ERROR "can inline main.func14" "func literal does not escape"
return x + 2
}
y, ok = map[int]func(int) int{ // ERROR "does not escape"
0: func(x int) int { return x + 1 }, // ERROR "can inline main.func15" "func literal escapes"
}[0]
if y(40) != 41 {
ppanic("y(40) != 41")
}
}
{
func() { // ERROR "func literal does not escape"
y := func(x int) int { // ERROR "can inline main.func16.1" "func literal does not escape"
return x + 2
}
y, ok = map[int]func(int) int{ // ERROR "does not escape"
0: func(x int) int { return x + 1 }, // ERROR "can inline main.func16.2" "func literal escapes"
}[0]
if y(40) != 41 {
ppanic("y(40) != 41")
}
}()
}
{
y := func(x int) int { // ERROR "can inline main.func17" "func literal does not escape"
return x + 2
}
y, ok = interface{}(func(x int) int { // ERROR "can inline main.func18" "does not escape"
return x + 1
}).(func(int) int)
if y(40) != 41 {
ppanic("y(40) != 41")
}
}
{
func() { // ERROR "func literal does not escape"
y := func(x int) int { // ERROR "can inline main.func19.1" "func literal does not escape"
return x + 2
}
y, ok = interface{}(func(x int) int { // ERROR "can inline main.func19.2" "does not escape"
return x + 1
}).(func(int) int)
if y(40) != 41 {
ppanic("y(40) != 41")
}
}()
}
{
x := 42
if y := func() int { // ERROR "can inline main.func20"
return x
}(); y != 42 { // ERROR "inlining call to main.func20"
ppanic("y != 42")
}
if y := func() int { // ERROR "can inline main.func21" "func literal does not escape"
return x
}; y() != 42 { // ERROR "inlining call to main.func21"
_ = y // prevent simple deadcode elimination after inlining
ppanic("y() != 42")
}
}
{
x := 42
if z := func(y int) int { // ERROR "can inline main.func22"
return func() int { // ERROR "can inline main.func22.1" "can inline main.main.func22.func30"
return x + y
}() // ERROR "inlining call to main.func22.1"
}(1); z != 43 { // ERROR "inlining call to main.func22" "inlining call to main.main.func22.func30"
ppanic("z != 43")
}
if z := func(y int) int { // ERROR "func literal does not escape" "can inline main.func23"
return func() int { // ERROR "can inline main.func23.1" "can inline main.main.func23.func31"
return x + y
}() // ERROR "inlining call to main.func23.1"
}; z(1) != 43 { // ERROR "inlining call to main.func23" "inlining call to main.main.func23.func31"
_ = z // prevent simple deadcode elimination after inlining
ppanic("z(1) != 43")
}
}
{
a := 1
func() { // ERROR "can inline main.func24"
func() { // ERROR "can inline main.func24" "can inline main.main.func24.func32"
a = 2
}() // ERROR "inlining call to main.func24"
}() // ERROR "inlining call to main.func24" "inlining call to main.main.func24.func32"
if a != 2 {
ppanic("a != 2")
}
}
{
b := 2
func(b int) { // ERROR "func literal does not escape"
func() { // ERROR "can inline main.func25.1"
b = 3
}() // ERROR "inlining call to main.func25.1"
if b != 3 {
ppanic("b != 3")
}
}(b)
if b != 2 {
ppanic("b != 2")
}
}
{
c := 3
func() { // ERROR "can inline main.func26"
c = 4
func() {
if c != 4 {
ppanic("c != 4")
}
recover() // prevent inlining
}()
}() // ERROR "inlining call to main.func26" "func literal does not escape"
if c != 4 {
ppanic("c != 4")
}
}
{
a := 2
// This has an unfortunate exponential growth, where as we visit each
// function, we inline the inner closure, and that constructs a new
// function for any closures inside the inner function, and then we
// revisit those. E.g., func34 and func36 are constructed by the inliner.
if r := func(x int) int { // ERROR "can inline main.func27"
b := 3
return func(y int) int { // ERROR "can inline main.func27.1" "can inline main.main.func27.func34"
c := 5
return func(z int) int { // ERROR "can inline main.func27.1.1" "can inline main.main.func27.func34.1" "can inline main.func27.main.func27.1.2" "can inline main.main.func27.main.main.func27.func34.func36"
return a*x + b*y + c*z
}(10) // ERROR "inlining call to main.func27.1.1"
}(100) // ERROR "inlining call to main.func27.1" "inlining call to main.func27.main.func27.1.2"
}(1000); r != 2350 { // ERROR "inlining call to main.func27" "inlining call to main.main.func27.func34" "inlining call to main.main.func27.main.main.func27.func34.func36"
ppanic("r != 2350")
}
}
{
a := 2
if r := func(x int) int { // ERROR "can inline main.func28"
b := 3
return func(y int) int { // ERROR "can inline main.func28.1" "can inline main.main.func28.func35"
c := 5
func(z int) { // ERROR "can inline main.func28.1.1" "can inline main.func28.main.func28.1.2" "can inline main.main.func28.func35.1" "can inline main.main.func28.main.main.func28.func35.func37"
a = a * x
b = b * y
c = c * z
}(10) // ERROR "inlining call to main.func28.1.1"
return a + c
}(100) + b // ERROR "inlining call to main.func28.1" "inlining call to main.func28.main.func28.1.2"
}(1000); r != 2350 { // ERROR "inlining call to main.func28" "inlining call to main.main.func28.func35" "inlining call to main.main.func28.main.main.func28.func35.func37"
ppanic("r != 2350")
}
if a != 2000 {
ppanic("a != 2000")
}
}
}
//go:noinline
func notmain() {
{
// This duplicates the first block in main, but without the "_ = x" for closure x.
// This allows dead code elimination of x before escape analysis,
// thus "func literal does not escape" should not appear.
if x := func() int { // ERROR "can inline notmain.func1"
return 1
}(); x != 1 { // ERROR "inlining call to notmain.func1"
ppanic("x != 1")
}
if x := func() int { // ERROR "can inline notmain.func2"
return 1
}; x() != 1 { // ERROR "inlining call to notmain.func2"
ppanic("x() != 1")
}
}
}
//go:noinline
func ppanic(s string) { // ERROR "leaking param: s"
panic(s) // ERROR "s escapes to heap"
}