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https://github.com/golang/go
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39986d28e4
[This is a roll-forward of CL 479095, which was reverted due to a bad interaction between inlining and escape analysis since fixed in CL 482355.] Currently, when the inliner is determining if a function is inlineable, it descends into the bodies of closures constructed by that function. This has several unfortunate consequences: - If the closure contains a disallowed operation (e.g., a defer), then the outer function can't be inlined. It makes sense that the *closure* can't be inlined in this case, but it doesn't make sense to punish the function that constructs the closure. - The hairiness of the closure counts against the inlining budget of the outer function. Since we currently copy the closure body when inlining the outer function, this makes sense from the perspective of export data size and binary size, but ultimately doesn't make much sense from the perspective of what should be inlineable. - Since the inliner walks into every closure created by an outer function in addition to starting a walk at every closure, this adds an n^2 factor to inlinability analysis. This CL simply drops this behavior. In std, this makes 57 more functions inlinable, and disallows inlining for 10 (due to the basic instability of our bottom-up inlining approach), for an net increase of 47 inlinable functions (+0.6%). This will help significantly with the performance of the functions to be added for #56102, which have a somewhat complicated nesting of closures with a performance-critical fast path. The downside of this seems to be a potential increase in export data and text size, but the practical impact of this seems to be negligible: │ before │ after │ │ bytes │ bytes vs base │ Go/binary 15.12Mi ± 0% 15.14Mi ± 0% +0.16% (n=1) Go/text 5.220Mi ± 0% 5.237Mi ± 0% +0.32% (n=1) Compile/binary 22.92Mi ± 0% 22.94Mi ± 0% +0.07% (n=1) Compile/text 8.428Mi ± 0% 8.435Mi ± 0% +0.08% (n=1) Updates #56102. Change-Id: I1f4fc96c71609c8feb59fecdb92b69ba7e3b5b41 Reviewed-on: https://go-review.googlesource.com/c/go/+/482356 Reviewed-by: Cuong Manh Le <cuong.manhle.vn@gmail.com> Run-TryBot: Than McIntosh <thanm@google.com> Reviewed-by: Cherry Mui <cherryyz@google.com> TryBot-Result: Gopher Robot <gobot@golang.org>
294 lines
8.0 KiB
Go
294 lines
8.0 KiB
Go
// Copyright 2017 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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// Check correctness of various closure corner cases
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// that are expected to be inlined
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package main
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var ok bool
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var sink int
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func main() {
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{
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if x := func() int { // ERROR "can inline main.func1"
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return 1
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}(); x != 1 { // ERROR "inlining call to main.func1"
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ppanic("x != 1")
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}
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if x := func() int { // ERROR "can inline main.func2" "func literal does not escape"
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return 1
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}; x() != 1 { // ERROR "inlining call to main.func2"
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ppanic("x() != 1")
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}
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}
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{
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if y := func(x int) int { // ERROR "can inline main.func3"
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return x + 2
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}(40); y != 42 { // ERROR "inlining call to main.func3"
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ppanic("y != 42")
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}
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if y := func(x int) int { // ERROR "can inline main.func4" "func literal does not escape"
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return x + 2
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}; y(40) != 42 { // ERROR "inlining call to main.func4"
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ppanic("y(40) != 42")
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}
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}
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{
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y := func(x int) int { // ERROR "can inline main.func5" "func literal does not escape"
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return x + 2
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}
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y = func(x int) int { // ERROR "can inline main.func6" "func literal does not escape"
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return x + 1
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}
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if y(40) != 41 {
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ppanic("y(40) != 41")
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}
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}
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{
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func() { // ERROR "func literal does not escape"
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y := func(x int) int { // ERROR "can inline main.func7.1" "func literal does not escape"
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return x + 2
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}
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y = func(x int) int { // ERROR "can inline main.func7.2" "func literal does not escape"
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return x + 1
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}
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if y(40) != 41 {
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ppanic("y(40) != 41")
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}
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}()
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}
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{
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y := func(x int) int { // ERROR "can inline main.func8" "func literal does not escape"
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return x + 2
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}
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y, sink = func(x int) int { // ERROR "can inline main.func9" "func literal does not escape"
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return x + 1
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}, 42
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if y(40) != 41 {
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ppanic("y(40) != 41")
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}
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}
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{
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func() { // ERROR "func literal does not escape"
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y := func(x int) int { // ERROR "can inline main.func10.1" "func literal does not escape"
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return x + 2
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}
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y, sink = func(x int) int { // ERROR "can inline main.func10.2" "func literal does not escape"
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return x + 1
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}, 42
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if y(40) != 41 {
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ppanic("y(40) != 41")
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}
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}()
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}
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{
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y := func(x int) int { // ERROR "can inline main.func11" "func literal does not escape"
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return x + 2
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}
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y, sink = func() (func(int) int, int) { // ERROR "can inline main.func12"
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return func(x int) int { // ERROR "can inline main.func12"
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return x + 1
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}, 42
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}() // ERROR "func literal does not escape" "inlining call to main.func12"
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if y(40) != 41 {
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ppanic("y(40) != 41")
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}
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}
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{
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func() { // ERROR "func literal does not escape"
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y := func(x int) int { // ERROR "func literal does not escape" "can inline main.func13.1"
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return x + 2
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}
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y, sink = func() (func(int) int, int) { // ERROR "can inline main.func13.2"
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return func(x int) int { // ERROR "can inline main.func13.2"
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return x + 1
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}, 42
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}() // ERROR "func literal does not escape" "inlining call to main.func13.2"
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if y(40) != 41 {
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ppanic("y(40) != 41")
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}
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}()
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}
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{
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y := func(x int) int { // ERROR "can inline main.func14" "func literal does not escape"
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return x + 2
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}
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y, ok = map[int]func(int) int{ // ERROR "does not escape"
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0: func(x int) int { return x + 1 }, // ERROR "can inline main.func15" "func literal escapes"
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}[0]
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if y(40) != 41 {
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ppanic("y(40) != 41")
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}
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}
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{
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func() { // ERROR "func literal does not escape"
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y := func(x int) int { // ERROR "can inline main.func16.1" "func literal does not escape"
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return x + 2
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}
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y, ok = map[int]func(int) int{ // ERROR "does not escape"
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0: func(x int) int { return x + 1 }, // ERROR "can inline main.func16.2" "func literal escapes"
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}[0]
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if y(40) != 41 {
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ppanic("y(40) != 41")
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}
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}()
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}
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{
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y := func(x int) int { // ERROR "can inline main.func17" "func literal does not escape"
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return x + 2
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}
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y, ok = interface{}(func(x int) int { // ERROR "can inline main.func18" "does not escape"
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return x + 1
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}).(func(int) int)
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if y(40) != 41 {
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ppanic("y(40) != 41")
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}
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}
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{
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func() { // ERROR "func literal does not escape"
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y := func(x int) int { // ERROR "can inline main.func19.1" "func literal does not escape"
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return x + 2
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}
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y, ok = interface{}(func(x int) int { // ERROR "can inline main.func19.2" "does not escape"
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return x + 1
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}).(func(int) int)
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if y(40) != 41 {
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ppanic("y(40) != 41")
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}
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}()
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}
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{
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x := 42
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if y := func() int { // ERROR "can inline main.func20"
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return x
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}(); y != 42 { // ERROR "inlining call to main.func20"
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ppanic("y != 42")
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}
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if y := func() int { // ERROR "can inline main.func21" "func literal does not escape"
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return x
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}; y() != 42 { // ERROR "inlining call to main.func21"
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ppanic("y() != 42")
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}
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}
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{
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x := 42
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if z := func(y int) int { // ERROR "can inline main.func22"
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return func() int { // ERROR "can inline main.func22.1" "can inline main.func30"
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return x + y
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}() // ERROR "inlining call to main.func22.1"
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}(1); z != 43 { // ERROR "inlining call to main.func22" "inlining call to main.func30"
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ppanic("z != 43")
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}
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if z := func(y int) int { // ERROR "func literal does not escape" "can inline main.func23"
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return func() int { // ERROR "can inline main.func23.1" "can inline main.func31"
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return x + y
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}() // ERROR "inlining call to main.func23.1"
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}; z(1) != 43 { // ERROR "inlining call to main.func23" "inlining call to main.func31"
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ppanic("z(1) != 43")
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}
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}
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{
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a := 1
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func() { // ERROR "can inline main.func24"
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func() { // ERROR "can inline main.func24" "can inline main.func32"
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a = 2
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}() // ERROR "inlining call to main.func24"
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}() // ERROR "inlining call to main.func24" "inlining call to main.func32"
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if a != 2 {
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ppanic("a != 2")
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}
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}
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{
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b := 2
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func(b int) { // ERROR "func literal does not escape"
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func() { // ERROR "can inline main.func25.1"
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b = 3
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}() // ERROR "inlining call to main.func25.1"
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if b != 3 {
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ppanic("b != 3")
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}
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}(b)
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if b != 2 {
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ppanic("b != 2")
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}
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}
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{
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c := 3
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func() { // ERROR "can inline main.func26"
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c = 4
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func() {
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if c != 4 {
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ppanic("c != 4")
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}
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recover() // prevent inlining
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}()
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}() // ERROR "inlining call to main.func26" "func literal does not escape"
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if c != 4 {
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ppanic("c != 4")
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}
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}
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{
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a := 2
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// This has an unfortunate exponential growth, where as we visit each
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// function, we inline the inner closure, and that constructs a new
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// function for any closures inside the inner function, and then we
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// revisit those. E.g., func34 and func36 are constructed by the inliner.
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if r := func(x int) int { // ERROR "can inline main.func27"
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b := 3
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return func(y int) int { // ERROR "can inline main.func27.1" "can inline main.func34"
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c := 5
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return func(z int) int { // ERROR "can inline main.func27.1.1" "can inline main.func27.(func)?2" "can inline main.func34.1" "can inline main.func36"
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return a*x + b*y + c*z
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}(10) // ERROR "inlining call to main.func27.1.1"
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}(100) // ERROR "inlining call to main.func27.1" "inlining call to main.func27.(func)?2"
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}(1000); r != 2350 { // ERROR "inlining call to main.func27" "inlining call to main.func34" "inlining call to main.func36"
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ppanic("r != 2350")
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}
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}
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{
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a := 2
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if r := func(x int) int { // ERROR "can inline main.func28"
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b := 3
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return func(y int) int { // ERROR "can inline main.func28.1" "can inline main.func35"
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c := 5
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func(z int) { // ERROR "can inline main.func28.1.1" "can inline main.func28.(func)?2" "can inline main.func35.1" "can inline main.func37"
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a = a * x
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b = b * y
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c = c * z
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}(10) // ERROR "inlining call to main.func28.1.1"
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return a + c
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}(100) + b // ERROR "inlining call to main.func28.1" "inlining call to main.func28.(func)?2"
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}(1000); r != 2350 { // ERROR "inlining call to main.func28" "inlining call to main.func35" "inlining call to main.func37"
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ppanic("r != 2350")
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}
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if a != 2000 {
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ppanic("a != 2000")
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}
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}
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}
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//go:noinline
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func ppanic(s string) { // ERROR "leaking param: s"
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panic(s) // ERROR "s escapes to heap"
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}
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