go/test/escape_array.go
Matthew Dempsky 606019cb4b cmd/compile: trim function name prefix from escape diagnostics
This information is redundant with the position information already
provided. Also, no other -m diagnostics print out function name.

While here, report parameter leak diagnostics against the parameter
declaration position rather than the function, and use Warnl for
"moved to heap" messages.

Test cases updated programmatically by removing the first word from
every "no match for" error emitted by run.go:

go run run.go |& \
  sed -E -n 's/^(.*):(.*): no match for `([^ ]* (.*))` in:$/\1!\2!\3!\4/p' | \
  while IFS='!' read -r fn line before after; do
    before=$(echo "$before" | sed 's/[.[\*^$()+?{|]/\\&/g')
    after=$(echo "$after" | sed -E 's/(\&|\\)/\\&/g')
    fn=$(find . -name "${fn}" | head -1)
    sed -i -E -e "${line}s/\"${before}\"/\"${after}\"/" "${fn}"
  done

Passes toolstash-check.

Change-Id: I6e02486b1409e4a8dbb2b9b816d22095835426b5
Reviewed-on: https://go-review.googlesource.com/c/go/+/195040
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
2019-09-16 15:30:51 +00:00

130 lines
3.6 KiB
Go

// errorcheck -0 -m -l
// 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 arrays and some large things
package foo
var Ssink *string
type U [2]*string
func bar(a, b *string) U { // ERROR "leaking param: a to result ~r2 level=0$" "leaking param: b to result ~r2 level=0$"
return U{a, b}
}
func foo(x U) U { // ERROR "leaking param: x to result ~r1 level=0$"
return U{x[1], x[0]}
}
func bff(a, b *string) U { // ERROR "leaking param: a to result ~r2 level=0$" "leaking param: b to result ~r2 level=0$"
return foo(foo(bar(a, b)))
}
func tbff1() *string {
a := "cat"
b := "dog" // ERROR "moved to heap: b$"
u := bff(&a, &b)
_ = u[0]
return &b
}
// BAD: need fine-grained analysis to track u[0] and u[1] differently.
func tbff2() *string {
a := "cat" // ERROR "moved to heap: a$"
b := "dog" // ERROR "moved to heap: b$"
u := bff(&a, &b)
_ = u[0]
return u[1]
}
func car(x U) *string { // ERROR "leaking param: x to result ~r1 level=0$"
return x[0]
}
// BAD: need fine-grained analysis to track x[0] and x[1] differently.
func fun(x U, y *string) *string { // ERROR "leaking param: x to result ~r2 level=0$" "leaking param: y to result ~r2 level=0$"
x[0] = y
return x[1]
}
func fup(x *U, y *string) *string { // ERROR "leaking param: x to result ~r2 level=1$" "leaking param: y$"
x[0] = y // leaking y to heap is intended
return x[1]
}
func fum(x *U, y **string) *string { // ERROR "leaking param: x to result ~r2 level=1$" "leaking param content: y$"
x[0] = *y
return x[1]
}
func fuo(x *U, y *U) *string { // ERROR "leaking param: x to result ~r2 level=1$" "leaking param content: y$"
x[0] = y[0]
return x[1]
}
// These two tests verify that:
// small array literals are stack allocated;
// pointers stored in small array literals do not escape;
// large array literals are heap allocated;
// pointers stored in large array literals escape.
func hugeLeaks1(x **string, y **string) { // ERROR "leaking param content: x" "y does not escape"
a := [10]*string{*y}
_ = a
// 4 x 4,000,000 exceeds MaxStackVarSize, therefore it must be heap allocated if pointers are 4 bytes or larger.
b := [4000000]*string{*x} // ERROR "moved to heap: b"
_ = b
}
func hugeLeaks2(x *string, y *string) { // ERROR "leaking param: x" "y does not escape"
a := [10]*string{y}
_ = a
// 4 x 4,000,000 exceeds MaxStackVarSize, therefore it must be heap allocated if pointers are 4 bytes or larger.
b := [4000000]*string{x} // ERROR "moved to heap: b"
_ = b
}
// BAD: x need not leak.
func doesNew1(x *string, y *string) { // ERROR "leaking param: x" "leaking param: y"
a := new([10]*string) // ERROR "new\(\[10\]\*string\) does not escape"
a[0] = x
b := new([65537]*string) // ERROR "new\(\[65537\]\*string\) escapes to heap"
b[0] = y
}
type a10 struct {
s *string
i [10]int32
}
type a65537 struct {
s *string
i [65537]int32
}
// BAD: x need not leak.
func doesNew2(x *string, y *string) { // ERROR "leaking param: x" "leaking param: y"
a := new(a10) // ERROR "new\(a10\) does not escape"
a.s = x
b := new(a65537) // ERROR "new\(a65537\) escapes to heap"
b.s = y
}
// BAD: x need not leak.
func doesMakeSlice(x *string, y *string) { // ERROR "leaking param: x" "leaking param: y"
a := make([]*string, 10) // ERROR "make\(\[\]\*string, 10\) does not escape"
a[0] = x
b := make([]*string, 65537) // ERROR "make\(\[\]\*string, 65537\) escapes to heap"
b[0] = y
}
func nonconstArray() {
n := 32
s1 := make([]int, n) // ERROR "make\(\[\]int, n\) escapes to heap"
s2 := make([]int, 0, n) // ERROR "make\(\[\]int, 0, n\) escapes to heap"
_, _ = s1, s2
}