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e99e9a6e01
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>
89 lines
1.5 KiB
Go
89 lines
1.5 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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// Tests escape analysis for range of arrays.
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// Compiles but need not run. Inlining is disabled.
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package main
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type A struct {
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b [3]uint64
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}
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type B struct {
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b [3]*uint64
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}
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func f(a A) int {
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for i, x := range &a.b {
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if x != 0 {
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return 64*i + int(x)
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}
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}
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return 0
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}
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func g(a *A) int { // ERROR "a does not escape"
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for i, x := range &a.b {
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if x != 0 {
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return 64*i + int(x)
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}
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}
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return 0
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}
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func h(a *B) *uint64 { // ERROR "leaking param: a to result ~r0 level=1"
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for i, x := range &a.b {
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if i == 0 {
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return x
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}
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}
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return nil
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}
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func h2(a *B) *uint64 { // ERROR "leaking param: a to result ~r0 level=1"
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p := &a.b
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for i, x := range p {
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if i == 0 {
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return x
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}
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}
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return nil
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}
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// Seems like below should be level=1, not 0.
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func k(a B) *uint64 { // ERROR "leaking param: a to result ~r0 level=0"
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for i, x := range &a.b {
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if i == 0 {
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return x
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}
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}
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return nil
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}
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var sink *uint64
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func main() {
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var a1, a2 A
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var b1, b2, b3, b4 B
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var x1, x2, x3, x4 uint64 // ERROR "moved to heap: x1" "moved to heap: x3"
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b1.b[0] = &x1
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b2.b[0] = &x2
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b3.b[0] = &x3
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b4.b[0] = &x4
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f(a1)
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g(&a2)
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sink = h(&b1)
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h(&b2)
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sink = h2(&b1)
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h2(&b4)
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x1 = 17
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println("*sink=", *sink) // Verify that sink addresses x1
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x3 = 42
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sink = k(b3)
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println("*sink=", *sink) // Verify that sink addresses x3
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}
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