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13baf4b2cd
This is a simple tweak to allow a bit more mid-stack inlining.
In cases like this:
func f() {
g()
}
We'd really like to inline f into its callers. It can't hurt.
We implement this optimization by making calls a bit cheaper, enough
to afford a single call in the function body, but not 2.
The remaining budget allows for some argument modification, or perhaps
a wrapping conditional:
func f(x int) {
g(x, 0)
}
func f(x int) {
if x > 0 {
g()
}
}
Update #19348
Change-Id: Ifb1ea0dd1db216c3fd5c453c31c3355561fe406f
Reviewed-on: https://go-review.googlesource.com/c/147361
Reviewed-by: Austin Clements <austin@google.com>
Reviewed-by: David Chase <drchase@google.com>
40 lines
1.2 KiB
Go
40 lines
1.2 KiB
Go
// errorcheck -0 -m -live
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// +build !windows,!js
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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 and liveness inferred for syscall.Syscall-like functions.
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package p
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import (
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"syscall"
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"unsafe"
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)
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func f(uintptr) // ERROR "f assuming arg#1 is unsafe uintptr"
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func g() { // ERROR "can inline g"
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var t int
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f(uintptr(unsafe.Pointer(&t))) // ERROR "live at call to f: .?autotmp" "g &t does not escape" "stack object .autotmp_[0-9]+ unsafe.Pointer$"
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}
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func h() { // ERROR "can inline h"
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var v int
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syscall.Syscall(0, 1, uintptr(unsafe.Pointer(&v)), 2) // ERROR "live at call to Syscall: .?autotmp" "h &v does not escape" "stack object .autotmp_[0-9]+ unsafe.Pointer$"
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}
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func i() { // ERROR "can inline i"
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var t int
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p := unsafe.Pointer(&t) // ERROR "i &t does not escape"
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f(uintptr(p)) // ERROR "live at call to f: .?autotmp" "stack object .autotmp_[0-9]+ unsafe.Pointer$"
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}
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func j() { // ERROR "can inline j"
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var v int
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p := unsafe.Pointer(&v) // ERROR "j &v does not escape"
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syscall.Syscall(0, 1, uintptr(p), 2) // ERROR "live at call to Syscall: .?autotmp" "stack object .autotmp_[0-9]+ unsafe.Pointer$"
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}
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