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go/test/oldescape_calls.go

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cmd/compile: update escape analysis tests for newescape The new escape analysis implementation tries to emit debugging diagnostics that are compatible with the existing implementation, but there's a handful of cases that are easier to handle by updating the test expectations instead. For regress tests that need updating, the original file is copied to oldescapeXXX.go.go with -newescape=false added to the //errorcheck line, while the file is updated in place with -newescape=true and new test requirements. Notable test changes: 1) escape_because.go looks for a lot of detailed internal debugging messages that are fairly particular to how esc.go works and that I haven't attempted to port over to escape.go yet. 2) There are a lot of "leaking param: x to result ~r1 level=-1" messages for code like func(p *int) *T { return &T{p} } that were simply wrong. Here &T must be heap allocated unconditionally (because it's being returned); and since p is stored into it, p escapes unconditionally too. esc.go incorrectly reports that p escapes conditionally only if the returned pointer escaped. 3) esc.go used to print each "leaking param" analysis result as it discovered them, which could lead to redundant messages (e.g., that a param leaks at level=0 and level=1). escape.go instead prints everything at the end, once it knows the shortest path to each sink. 4) esc.go didn't precisely model direct-interface types, resulting in some values unnecessarily escaping to the heap when stored into non-escaping interface values. 5) For functions written in assembly, esc.go only printed "does not escape" messages, whereas escape.go prints "does not escape" or "leaking param" as appropriate, consistent with the behavior for functions written in Go. 6) 12 tests included "BAD" annotations identifying cases where esc.go was unnecessarily heap allocating something. These are all fixed by escape.go. Updates #23109. Change-Id: Iabc9eb14c94c9cadde3b183478d1fd54f013502f Reviewed-on: https://go-review.googlesource.com/c/go/+/170447 Run-TryBot: Matthew Dempsky <mdempsky@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: David Chase <drchase@google.com>
2019-04-02 15:44:13 -06:00
// errorcheck -0 -m -l -newescape=false
// Copyright 2015 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 escape analysis for function parameters.
// In this test almost everything is BAD except the simplest cases
// where input directly flows to output.
package foo
func f(buf []byte) []byte { // ERROR "leaking param: buf to result ~r1 level=0$"
return buf
}
func g(*byte) string
func h(e int) {
var x [32]byte // ERROR "moved to heap: x$"
g(&f(x[:])[0])
}
type Node struct {
s string
left, right *Node
}
func walk(np **Node) int { // ERROR "leaking param content: np"
n := *np
w := len(n.s)
if n == nil {
return 0
}
wl := walk(&n.left)
wr := walk(&n.right)
if wl < wr {
n.left, n.right = n.right, n.left
wl, wr = wr, wl
}
*np = n
return w + wl + wr
}
// Test for bug where func var f used prototype's escape analysis results.
func prototype(xyz []string) {} // ERROR "prototype xyz does not escape"
func bar() {
var got [][]string
f := prototype
f = func(ss []string) { got = append(got, ss) } // ERROR "leaking param: ss" "func literal does not escape"
s := "string"
f([]string{s}) // ERROR "\[\]string literal escapes to heap"
}