cmd/gc: allocate buffers for non-escaping string conversions on stack
Support the following conversions in escape analysis:
[]rune("foo")
[]byte("foo")
string([]rune{})
If the result does not escape, allocate temp buffer on stack
and pass it to runtime functions.
Change-Id: I1d075907eab8b0109ad7ad1878104b02b3d5c690
Reviewed-on: https://go-review.googlesource.com/3590
Reviewed-by: Russ Cox <rsc@golang.org>
diff --git a/test/escape2n.go b/test/escape2n.go
index 31f4ed0..d9d95e8 100644
--- a/test/escape2n.go
+++ b/test/escape2n.go
@@ -212,7 +212,7 @@
func foo21a() func() int {
x := 42 // ERROR "moved to heap: x"
return func() int { // ERROR "func literal escapes to heap"
- x++ // ERROR "&x escapes to heap"
+ x++ // ERROR "&x escapes to heap"
return x
}
}
@@ -1560,14 +1560,14 @@
func ptrlitNoEscape2() {
// Literal does not escape, but element does.
- i := 0 // ERROR "moved to heap: i"
+ i := 0 // ERROR "moved to heap: i"
x := &Lit{&i} // ERROR "&Lit literal does not escape" "&i escapes to heap"
sink = *x
}
func ptrlitEscape() {
// Both literal and element escape.
- i := 0 // ERROR "moved to heap: i"
+ i := 0 // ERROR "moved to heap: i"
x := &Lit{&i} // ERROR "&Lit literal escapes to heap" "&i escapes to heap"
sink = x
}
@@ -1619,7 +1619,7 @@
// to just x, and thus &i looks escaping.
func fieldFlowTracking() {
var x StructWithString
- i := 0 // ERROR "moved to heap: i"
+ i := 0 // ERROR "moved to heap: i"
x.p = &i // ERROR "&i escapes to heap"
sink = x.s
}
@@ -1703,3 +1703,51 @@
s := string(x) // ERROR "string\(x\) escapes to heap" "moved to heap: s"
sink = &s // ERROR "&s escapes to heap"
}
+
+func stringtoslicebyte0() {
+ s := "foo"
+ x := []byte(s) // ERROR "\(\[\]byte\)\(s\) does not escape"
+ _ = x
+}
+
+func stringtoslicebyte1() []byte {
+ s := "foo"
+ return []byte(s) // ERROR "\(\[\]byte\)\(s\) escapes to heap"
+}
+
+func stringtoslicebyte2() {
+ s := "foo"
+ sink = []byte(s) // ERROR "\(\[\]byte\)\(s\) escapes to heap"
+}
+
+func stringtoslicerune0() {
+ s := "foo"
+ x := []rune(s) // ERROR "\(\[\]rune\)\(s\) does not escape"
+ _ = x
+}
+
+func stringtoslicerune1() []rune {
+ s := "foo"
+ return []rune(s) // ERROR "\(\[\]rune\)\(s\) escapes to heap"
+}
+
+func stringtoslicerune2() {
+ s := "foo"
+ sink = []rune(s) // ERROR "\(\[\]rune\)\(s\) escapes to heap"
+}
+
+func slicerunetostring0() {
+ r := []rune{1, 2, 3} // ERROR "\[\]rune literal does not escape"
+ s := string(r) // ERROR "string\(r\) does not escape"
+ _ = s
+}
+
+func slicerunetostring1() string {
+ r := []rune{1, 2, 3} // ERROR "\[\]rune literal does not escape"
+ return string(r) // ERROR "string\(r\) escapes to heap"
+}
+
+func slicerunetostring2() {
+ r := []rune{1, 2, 3} // ERROR "\[\]rune literal does not escape"
+ sink = string(r) // ERROR "string\(r\) escapes to heap"
+}
