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Calls to a closure held in a local, non-escaping, variable can be inlined, provided the closure body can be inlined and the variable is never written to. The current implementation has the following limitations: - closures with captured variables are not inlined because doing so naively triggers invariant violation in the SSA phase - re-assignment check is currently approximated by checking the Addrtaken property of the variable which should be safe but may miss optimization opportunities if the address is not used for a write before the invocation Updates #15561 Change-Id: I508cad5d28f027bd7e933b1f793c14dcfef8b5a1 Reviewed-on: https://go-review.googlesource.com/65071 Run-TryBot: Daniel Martí <mvdan@mvdan.cc> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Hugues Bruant <hugues.bruant@gmail.com> Reviewed-by: Keith Randall <khr@golang.org>
132 lines
3.1 KiB
Go
132 lines
3.1 KiB
Go
// errorcheck -0 -m
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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, using compiler diagnostic flags, that inlining is working.
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// Compiles but does not run.
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package foo
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import (
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"errors"
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"unsafe"
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)
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func add2(p *byte, n uintptr) *byte { // ERROR "can inline add2" "leaking param: p to result"
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return (*byte)(add1(unsafe.Pointer(p), n)) // ERROR "inlining call to add1"
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}
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func add1(p unsafe.Pointer, x uintptr) unsafe.Pointer { // ERROR "can inline add1" "leaking param: p to result"
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return unsafe.Pointer(uintptr(p) + x)
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}
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func f(x *byte) *byte { // ERROR "can inline f" "leaking param: x to result"
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return add2(x, 1) // ERROR "inlining call to add2" "inlining call to add1"
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}
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//go:noinline
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func g(x int) int {
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return x + 1
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}
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func h(x int) int { // ERROR "can inline h"
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return x + 2
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}
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func i(x int) int { // ERROR "can inline i"
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const y = 2
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return x + y
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}
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func j(x int) int { // ERROR "can inline j"
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switch {
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case x > 0:
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return x + 2
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default:
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return x + 1
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}
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}
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var somethingWrong error = errors.New("something went wrong")
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// local closures can be inlined
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func l(x, y int) (int, int, error) {
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e := func(err error) (int, int, error) { // ERROR "can inline l.func1" "func literal does not escape" "leaking param: err to result"
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return 0, 0, err
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}
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if x == y {
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e(somethingWrong) // ERROR "inlining call to l.func1"
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}
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return y, x, nil
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}
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// any re-assignment prevents closure inlining
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func m() int {
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foo := func() int { return 1 } // ERROR "can inline m.func1" "func literal does not escape"
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x := foo()
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foo = func() int { return 2 } // ERROR "can inline m.func2" "func literal does not escape"
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return x + foo()
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}
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// address taking prevents closure inlining
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func n() int {
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foo := func() int { return 1 } // ERROR "can inline n.func1" "func literal does not escape"
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bar := &foo // ERROR "&foo does not escape"
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x := (*bar)() + foo()
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return x
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}
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// make sure assignment inside closure is detected
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func o() int {
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foo := func() int { return 1 } // ERROR "can inline o.func1" "func literal does not escape"
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func(x int) { // ERROR "func literal does not escape"
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if x > 10 {
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foo = func() int { return 2 } // ERROR "can inline o.func2" "func literal escapes"
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}
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}(11)
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return foo()
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}
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func p() int {
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return func() int { return 42 }() // ERROR "can inline p.func1" "inlining call to p.func1"
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}
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// can't currently inline functions with a break statement
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func switchBreak(x, y int) int {
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var n int
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switch x {
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case 0:
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n = 1
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Done:
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switch y {
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case 0:
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n += 10
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break Done
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}
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n = 2
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}
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return n
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}
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// can't currently inline functions with a type switch
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func switchType(x interface{}) int { // ERROR "switchType x does not escape"
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switch x.(type) {
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case int:
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return x.(int)
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default:
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return 0
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}
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}
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type T struct{}
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func (T) meth(int, int) {} // ERROR "can inline T.meth"
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func k() (T, int, int) { return T{}, 0, 0 } // ERROR "can inline k"
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func _() { // ERROR "can inline _"
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T.meth(k()) // ERROR "inlining call to k" "inlining call to T.meth"
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}
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