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![Matthew Dempsky](/assets/img/avatar_default.png)
The compiler renames anonymous and blank result parameters to ~rN or ~bN, but the current semantics for computing N are rather annoying and difficult to reproduce cleanly. They also lead to difficult to read escape analysis results in tests. This CL changes N to always be calculated as the parameter's index within the function's result parameter tuple. E.g., if a function has a single result, it will now always be named "~r0". The normative change to this CL is fairly simple, but it requires updating a lot of test expectations. Change-Id: I58a3c94de00cb822cb94efe52d115531193c993c Reviewed-on: https://go-review.googlesource.com/c/go/+/323010 Trust: Matthew Dempsky <mdempsky@google.com> Trust: Dan Scales <danscales@google.com> Run-TryBot: Matthew Dempsky <mdempsky@google.com> TryBot-Result: Go Bot <gobot@golang.org> Reviewed-by: Dan Scales <danscales@google.com>
55 lines
1.3 KiB
Go
55 lines
1.3 KiB
Go
// errorcheck -0 -m -l
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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 for function parameters.
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// In this test almost everything is BAD except the simplest cases
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// where input directly flows to output.
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package foo
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func f(buf []byte) []byte { // ERROR "leaking param: buf to result ~r0 level=0$"
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return buf
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}
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func g(*byte) string
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func h(e int) {
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var x [32]byte // ERROR "moved to heap: x$"
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g(&f(x[:])[0])
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}
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type Node struct {
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s string
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left, right *Node
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}
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func walk(np **Node) int { // ERROR "leaking param content: np"
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n := *np
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w := len(n.s)
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if n == nil {
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return 0
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}
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wl := walk(&n.left)
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wr := walk(&n.right)
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if wl < wr {
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n.left, n.right = n.right, n.left // ERROR "ignoring self-assignment"
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wl, wr = wr, wl
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}
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*np = n
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return w + wl + wr
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}
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// Test for bug where func var f used prototype's escape analysis results.
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func prototype(xyz []string) {} // ERROR "xyz does not escape"
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func bar() {
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var got [][]string
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f := prototype
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f = func(ss []string) { got = append(got, ss) } // ERROR "leaking param: ss" "func literal does not escape"
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s := "string"
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f([]string{s}) // ERROR "\[\]string{...} escapes to heap"
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}
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