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2d56dee61b
This should probably be considered "experimental" at this stage, but what it needs is feedback from adventurous adopters. I think the data structure used for describing escape reasons might be extendable to allow a cleanup of the underlying algorithms, which suffers from insufficiently separated concerns (the graph does not deal well with escape level adjustments, so it is augmented by a second custom-walk portion of the "flood" phase. It would be better to put it all, including level adjustments, in a single graph structure, and then simply flood the graph. Tweaked to avoid allocations in the no-logging case. Modified run.go to ignore lines with leading "#" in the output (since it can never match a line), and in -update_errors to ignore leading tabs in output lines and to normalize embedded filenames. Currently requires -m -m because otherwise the noise/update burden for the other escape tests is considerable. There is a partial test. Existing escape analysis tests seem to cover all except the panic case and what looks like it might be unreachable code in escape analysis. Fixes #10526. Change-Id: I2524fdec54facae48b00b2548e25d9e46fcaf832 Reviewed-on: https://go-review.googlesource.com/18041 Run-TryBot: David Chase <drchase@google.com> TryBot-Result: Gobot Gobot <gobot@golang.org> Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
178 lines
6.7 KiB
Go
178 lines
6.7 KiB
Go
// errorcheck -0 -m -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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// Note the doubled -m; this tests the "because" explanations for escapes,
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// and is likely to be annoyingly fragile under compiler change.
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// As long as the explanations look reasonably sane, meaning eyeball verify output of
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// go build -gcflags '-l -m -m' escape_because.go
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// and investigate changes, feel free to update with
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// go run run.go -update_errors -- escape_because.go
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package main
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func main() {
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}
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var sink interface{}
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type pair struct {
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x, y *int
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}
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type Pairy interface {
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EqualParts() bool
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}
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func (p *pair) EqualParts() bool { // ERROR "\(\*pair\).EqualParts p does not escape$"
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return p != nil && (p.x == p.y || *p.x == *p.y)
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}
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func f1(p *int) { // ERROR "from \[3\]\*int literal \(array literal element\) at escape_because.go:34$" "from a \(assigned\) at escape_because.go:34$" "from a \(interface-converted\) at escape_because.go:35$" "from sink \(assigned to top level variable\) at escape_because.go:19$" "leaking param: p$"
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a := [3]*int{p, nil, nil}
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sink = a // ERROR "a escapes to heap$" "from sink \(assigned to top level variable\) at escape_because.go:19$"
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}
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func f2(q *int) { // ERROR "from &u \(address-of\) at escape_because.go:43$" "from &u \(interface-converted\) at escape_because.go:43$" "from pair literal \(struct literal element\) at escape_because.go:41$" "from s \(assigned\) at escape_because.go:40$" "from sink \(assigned to top level variable\) at escape_because.go:19$" "from t \(assigned\) at escape_because.go:41$" "from u \(assigned\) at escape_because.go:42$" "leaking param: q$"
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s := q
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t := pair{s, nil}
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u := t // ERROR "moved to heap: u$"
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sink = &u // ERROR "&u escapes to heap$" "from &u \(interface-converted\) at escape_because.go:43$" "from sink \(assigned to top level variable\) at escape_because.go:19$"
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}
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func f3(r *int) interface{} { // ERROR "from \[\]\*int literal \(slice-literal-element\) at escape_because.go:47$" "from c \(assigned\) at escape_because.go:47$" "from c \(interface-converted\) at escape_because.go:48$" "from ~r1 \(return\) at escape_because.go:46$" "leaking param: r to result ~r1 level=-1$"
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c := []*int{r} // ERROR "\[\]\*int literal escapes to heap$" "from c \(assigned\) at escape_because.go:47$" "from c \(interface-converted\) at escape_because.go:48$" "from ~r1 \(return\) at escape_because.go:46$"
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return c // "return" // ERROR "c escapes to heap$" "from ~r1 \(return\) at escape_because.go:46$"
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}
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func f4(a *int, s []*int) int { // ERROR "from \*s \(indirection\) at escape_because.go:51$" "from append\(s, a\) \(appended to slice\) at escape_because.go:52$" "from append\(s, a\) \(appendee slice\) at escape_because.go:52$" "leaking param content: s$" "leaking param: a$"
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s = append(s, a)
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return *(s[0])
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}
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func f5(s1, s2 []*int) int { // ERROR "from \*s1 \(indirection\) at escape_because.go:56$" "from \*s2 \(indirection\) at escape_because.go:56$" "from append\(s1, s2...\) \(appended slice...\) at escape_because.go:57$" "from append\(s1, s2...\) \(appendee slice\) at escape_because.go:57$" "leaking param content: s1$" "leaking param content: s2$"
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s1 = append(s1, s2...)
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return *(s1[0])
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}
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func f6(x, y *int) bool { // ERROR "f6 x does not escape$" "f6 y does not escape$"
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p := pair{x, y}
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var P Pairy = &p // ERROR "f6 &p does not escape$"
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pp := P.(*pair)
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return pp.EqualParts()
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}
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func f7(x map[int]*int, y int) *int { // ERROR "f7 x does not escape$"
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z, ok := x[y]
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if !ok {
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return nil
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}
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return z
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}
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func f8(x int, y *int) *int { // ERROR "from ~r2 \(return\) at escape_because.go:76$" "from ~r2 \(returned from recursive function\) at escape_because.go:76$" "leaking param: y$" "moved to heap: x$"
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if x <= 0 {
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return y
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}
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x--
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return f8(*y, &x) // ERROR "&x escapes to heap$" "from y \(arg to recursive call\) at escape_because.go:76$" "from ~r2 \(return\) at escape_because.go:76$" "from ~r2 \(returned from recursive function\) at escape_because.go:76$"
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}
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func f9(x int, y ...*int) *int { // ERROR "from y\[0\] \(dot of pointer\) at escape_because.go:86$" "from ~r2 \(return\) at escape_because.go:84$" "from ~r2 \(returned from recursive function\) at escape_because.go:84$" "leaking param content: y$" "leaking param: y to result ~r2 level=1$" "moved to heap: x$"
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if x <= 0 {
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return y[0]
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}
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x--
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return f9(*y[0], &x) // ERROR "&x escapes to heap$" "f9 ... argument does not escape$" "from ... argument \(... arg to recursive call\) at escape_because.go:89$"
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}
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func f10(x map[*int]*int, y, z *int) *int { // ERROR "f10 x does not escape$" "from x\[y\] \(key of map put\) at escape_because.go:93$" "from x\[y\] \(value of map put\) at escape_because.go:93$" "leaking param: y$" "leaking param: z$"
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x[y] = z
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return z
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}
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func f11(x map[*int]*int, y, z *int) map[*int]*int { // ERROR "f11 x does not escape$" "from map\[\*int\]\*int literal \(map literal key\) at escape_because.go:98$" "from map\[\*int\]\*int literal \(map literal value\) at escape_because.go:98$" "leaking param: y$" "leaking param: z$"
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return map[*int]*int{y: z} // ERROR "from ~r3 \(return\) at escape_because.go:97$" "map\[\*int\]\*int literal escapes to heap$"
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}
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// The list below is all of the why-escapes messages seen building the escape analysis tests.
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/*
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for i in escape*go ; do echo compile $i; go build -gcflags '-l -m -m' $i >& `basename $i .go`.log ; done
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grep 'from .* at ' escape*.log | sed -e 's/^.*(\([^()]*\))[^()]*$/\1/' | sort -u
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*/
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// sed RE above assumes that (reason) is the last parenthesized phrase in the line,
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// and that none of the reasons contains any parentheses
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/*
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... arg to recursive call
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address-of
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appended slice...
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appended to slice
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appendee slice
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arg to ...
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arg to recursive call
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array literal element
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array-element-equals
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assign-pair
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assign-pair-dot-type
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assign-pair-func-call
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assigned
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assigned to top level variable
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call part
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captured by a closure
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closure-var
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converted
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copied slice
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defer func
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defer func ...
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defer func arg
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dot
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dot of pointer
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dot-equals
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fixed-array-index-of
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go func
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go func ...
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go func arg
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indirection
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interface-converted
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key of map put
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map literal key
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map literal value
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parameter to indirect call
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passed to function[content escapes]
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passed to function[unknown]
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passed-to-and-returned-from-function
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pointer literal
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range
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range-deref
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receiver in indirect call
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return
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returned from recursive function
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send
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slice
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slice-element-equals
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slice-literal-element
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star-dot-equals
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star-equals
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struct literal element
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switch case
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too large for stack
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value of map put
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*/
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// Expected, but not yet seen (they may be unreachable):
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/*
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append-first-arg
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assign-pair-mapr
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assign-pair-receive
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call receiver
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map index
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panic
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pointer literal [assign]
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slice literal element
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*/
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