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go/test/escape4.go
Hugues Bruant 4f70a2a699 cmd/compile: inline calls to local closures
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>
2017-10-11 22:32:36 +00:00

58 lines
1.4 KiB
Go

// errorcheck -0 -m
// Copyright 2010 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, using compiler diagnostic flags, that the escape analysis is working.
// Compiles but does not run. Inlining is enabled.
package foo
var p *int
func alloc(x int) *int { // ERROR "can inline alloc" "moved to heap: x"
return &x // ERROR "&x escapes to heap"
}
var f func()
func f1() {
p = alloc(2) // ERROR "inlining call to alloc" "&x escapes to heap" "moved to heap: x"
// Escape analysis used to miss inlined code in closures.
func() { // ERROR "can inline f1.func1"
p = alloc(3) // ERROR "inlining call to alloc"
}() // ERROR "inlining call to f1.func1" "inlining call to alloc" "&x escapes to heap" "moved to heap: x"
f = func() { // ERROR "func literal escapes to heap" "can inline f1.func2"
p = alloc(3) // ERROR "inlining call to alloc" "&x escapes to heap" "moved to heap: x"
}
f()
}
func f2() {} // ERROR "can inline f2"
// No inline for panic, recover.
func f3() { panic(1) }
func f4() { recover() }
func f5() *byte {
type T struct {
x [1]byte
}
t := new(T) // ERROR "new.T. escapes to heap"
return &t.x[0] // ERROR "&t.x.0. escapes to heap"
}
func f6() *byte {
type T struct {
x struct {
y byte
}
}
t := new(T) // ERROR "new.T. escapes to heap"
return &t.x.y // ERROR "&t.x.y escapes to heap"
}