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go/test/reorder2.go
Russ Cox b700cb4974 cmd/gc: shorten temporary lifetimes when possible
The new channel and map runtime routines take pointers
to values, typically temporaries. Without help, the compiler
cannot tell when those temporaries stop being needed,
because it isn't sure what happened to the pointer.
Arrange to insert explicit VARKILL instructions for these
temporaries so that the liveness analysis can avoid seeing
them as "ambiguously live".

The change is made in order.c, which was already in charge of
introducing temporaries to preserve the order-of-evaluation
guarantees. Now its job has expanded to include introducing
temporaries as needed by runtime routines, and then also
inserting the VARKILL annotations for all these temporaries,
so that their lifetimes can be shortened.

In order to do its job for the map runtime routines, order.c arranges
that all map lookups or map assignments have the form:

        x = m[k]
        x, y = m[k]
        m[k] = x

where x, y, and k are simple variables (often temporaries).
Likewise, receiving from a channel is now always:

        x = <-c

In order to provide the map guarantee, order.c is responsible for
rewriting x op= y into x = x op y, so that m[k] += z becomes

        t = m[k]
        t2 = t + z
        m[k] = t2

While here, fix a few bugs in order.c's traversal: it was failing to
walk into select and switch case bodies, so order of evaluation
guarantees were not preserved in those situations.
Added tests to test/reorder2.go.

Fixes #7671.

In gc/popt's temporary-merging optimization, allow merging
of temporaries with their address taken as long as the liveness
ranges do not intersect. (There is a good chance of that now
that we have VARKILL annotations to limit the liveness range.)

Explicitly killing temporaries cuts the number of ambiguously
live temporaries that must be zeroed in the godoc binary from
860 to 711, or -17%. There is more work to be done, but this
is a good checkpoint.

Update #7345

LGTM=khr
R=khr
CC=golang-codereviews
https://golang.org/cl/81940043
2014-04-01 13:31:38 -04:00

344 lines
7.3 KiB
Go

// run
// Copyright 2010 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 reorderings; derived from fixedbugs/bug294.go.
package main
var log string
type TT int
func (t TT) a(s string) TT {
log += "a(" + s + ")"
return t
}
func (TT) b(s string) string {
log += "b(" + s + ")"
return s
}
type F func(s string) F
func a(s string) F {
log += "a(" + s + ")"
return F(a)
}
func b(s string) string {
log += "b(" + s + ")"
return s
}
type I interface {
a(s string) I
b(s string) string
}
type T1 int
func (t T1) a(s string) I {
log += "a(" + s + ")"
return t
}
func (T1) b(s string) string {
log += "b(" + s + ")"
return s
}
// f(g(), h()) where g is not inlinable but h is will have the same problem.
// As will x := g() + h() (same conditions).
// And g() <- h().
func f(x, y string) {
log += "f(" + x + ", " + y + ")"
}
func ff(x, y string) {
for false {
} // prevent inl
log += "ff(" + x + ", " + y + ")"
}
func h(x string) string {
log += "h(" + x + ")"
return x
}
func g(x string) string {
for false {
} // prevent inl
log += "g(" + x + ")"
return x
}
func main() {
err := 0
var t TT
if a("1")("2")("3"); log != "a(1)a(2)a(3)" {
println("expecting a(1)a(2)a(3) , got ", log)
err++
}
log = ""
if t.a("1").a(t.b("2")); log != "a(1)b(2)a(2)" {
println("expecting a(1)b(2)a(2), got ", log)
err++
}
log = ""
if a("3")(b("4"))(b("5")); log != "a(3)b(4)a(4)b(5)a(5)" {
println("expecting a(3)b(4)a(4)b(5)a(5), got ", log)
err++
}
log = ""
var i I = T1(0)
if i.a("6").a(i.b("7")).a(i.b("8")).a(i.b("9")); log != "a(6)b(7)a(7)b(8)a(8)b(9)a(9)" {
println("expecting a(6)ba(7)ba(8)ba(9), got", log)
err++
}
log = ""
if s := t.a("1").b("3"); log != "a(1)b(3)" || s != "3" {
println("expecting a(1)b(3) and 3, got ", log, " and ", s)
err++
}
log = ""
if s := t.a("1").a(t.b("2")).b("3") + t.a("4").b("5"); log != "a(1)b(2)a(2)b(3)a(4)b(5)" || s != "35" {
println("expecting a(1)b(2)a(2)b(3)a(4)b(5) and 35, got ", log, " and ", s)
err++
}
log = ""
if s := t.a("4").b("5") + t.a("1").a(t.b("2")).b("3"); log != "a(4)b(5)a(1)b(2)a(2)b(3)" || s != "53" {
println("expecting a(4)b(5)a(1)b(2)a(2)b(3) and 35, got ", log, " and ", s)
err++
}
log = ""
if ff(g("1"), g("2")); log != "g(1)g(2)ff(1, 2)" {
println("expecting g(1)g(2)ff..., got ", log)
err++
}
log = ""
if ff(g("1"), h("2")); log != "g(1)h(2)ff(1, 2)" {
println("expecting g(1)h(2)ff..., got ", log)
err++
}
log = ""
if ff(h("1"), g("2")); log != "h(1)g(2)ff(1, 2)" {
println("expecting h(1)g(2)ff..., got ", log)
err++
}
log = ""
if ff(h("1"), h("2")); log != "h(1)h(2)ff(1, 2)" {
println("expecting h(1)h(2)ff..., got ", log)
err++
}
log = ""
if s := g("1") + g("2"); log != "g(1)g(2)" || s != "12" {
println("expecting g1g2 and 12, got ", log, " and ", s)
err++
}
log = ""
if s := g("1") + h("2"); log != "g(1)h(2)" || s != "12" {
println("expecting g1h2 and 12, got ", log, " and ", s)
err++
}
log = ""
if s := h("1") + g("2"); log != "h(1)g(2)" || s != "12" {
println("expecting h1g2 and 12, got ", log, " and ", s)
err++
}
log = ""
if s := h("1") + h("2"); log != "h(1)h(2)" || s != "12" {
println("expecting h1h2 and 12, got ", log, " and ", s)
err++
}
log = ""
x := 0
switch x {
case 0:
if a("1")("2")("3"); log != "a(1)a(2)a(3)" {
println("in switch, expecting a(1)a(2)a(3) , got ", log)
err++
}
log = ""
if t.a("1").a(t.b("2")); log != "a(1)b(2)a(2)" {
println("in switch, expecting a(1)b(2)a(2), got ", log)
err++
}
log = ""
if a("3")(b("4"))(b("5")); log != "a(3)b(4)a(4)b(5)a(5)" {
println("in switch, expecting a(3)b(4)a(4)b(5)a(5), got ", log)
err++
}
log = ""
var i I = T1(0)
if i.a("6").a(i.b("7")).a(i.b("8")).a(i.b("9")); log != "a(6)b(7)a(7)b(8)a(8)b(9)a(9)" {
println("in switch, expecting a(6)ba(7)ba(8)ba(9), got", log)
err++
}
log = ""
}
c := make(chan int, 1)
c <- 1
select {
case c <- 0:
case c <- 1:
case <-c:
if a("1")("2")("3"); log != "a(1)a(2)a(3)" {
println("in select1, expecting a(1)a(2)a(3) , got ", log)
err++
}
log = ""
if t.a("1").a(t.b("2")); log != "a(1)b(2)a(2)" {
println("in select1, expecting a(1)b(2)a(2), got ", log)
err++
}
log = ""
if a("3")(b("4"))(b("5")); log != "a(3)b(4)a(4)b(5)a(5)" {
println("in select1, expecting a(3)b(4)a(4)b(5)a(5), got ", log)
err++
}
log = ""
var i I = T1(0)
if i.a("6").a(i.b("7")).a(i.b("8")).a(i.b("9")); log != "a(6)b(7)a(7)b(8)a(8)b(9)a(9)" {
println("in select1, expecting a(6)ba(7)ba(8)ba(9), got", log)
err++
}
log = ""
}
c <- 1
select {
case <-c:
if a("1")("2")("3"); log != "a(1)a(2)a(3)" {
println("in select2, expecting a(1)a(2)a(3) , got ", log)
err++
}
log = ""
if t.a("1").a(t.b("2")); log != "a(1)b(2)a(2)" {
println("in select2, expecting a(1)b(2)a(2), got ", log)
err++
}
log = ""
if a("3")(b("4"))(b("5")); log != "a(3)b(4)a(4)b(5)a(5)" {
println("in select2, expecting a(3)b(4)a(4)b(5)a(5), got ", log)
err++
}
log = ""
var i I = T1(0)
if i.a("6").a(i.b("7")).a(i.b("8")).a(i.b("9")); log != "a(6)b(7)a(7)b(8)a(8)b(9)a(9)" {
println("in select2, expecting a(6)ba(7)ba(8)ba(9), got", log)
err++
}
log = ""
}
c <- 1
select {
default:
case c<-1:
case <-c:
if a("1")("2")("3"); log != "a(1)a(2)a(3)" {
println("in select3, expecting a(1)a(2)a(3) , got ", log)
err++
}
log = ""
if t.a("1").a(t.b("2")); log != "a(1)b(2)a(2)" {
println("in select3, expecting a(1)b(2)a(2), got ", log)
err++
}
log = ""
if a("3")(b("4"))(b("5")); log != "a(3)b(4)a(4)b(5)a(5)" {
println("in select3, expecting a(3)b(4)a(4)b(5)a(5), got ", log)
err++
}
log = ""
var i I = T1(0)
if i.a("6").a(i.b("7")).a(i.b("8")).a(i.b("9")); log != "a(6)b(7)a(7)b(8)a(8)b(9)a(9)" {
println("in select3, expecting a(6)ba(7)ba(8)ba(9), got", log)
err++
}
log = ""
}
c <- 1
select {
default:
case <-c:
if a("1")("2")("3"); log != "a(1)a(2)a(3)" {
println("in select4, expecting a(1)a(2)a(3) , got ", log)
err++
}
log = ""
if t.a("1").a(t.b("2")); log != "a(1)b(2)a(2)" {
println("in select4, expecting a(1)b(2)a(2), got ", log)
err++
}
log = ""
if a("3")(b("4"))(b("5")); log != "a(3)b(4)a(4)b(5)a(5)" {
println("in select4, expecting a(3)b(4)a(4)b(5)a(5), got ", log)
err++
}
log = ""
var i I = T1(0)
if i.a("6").a(i.b("7")).a(i.b("8")).a(i.b("9")); log != "a(6)b(7)a(7)b(8)a(8)b(9)a(9)" {
println("in select4, expecting a(6)ba(7)ba(8)ba(9), got", log)
err++
}
log = ""
}
select {
case <-c:
case <-c:
default:
if a("1")("2")("3"); log != "a(1)a(2)a(3)" {
println("in select5, expecting a(1)a(2)a(3) , got ", log)
err++
}
log = ""
if t.a("1").a(t.b("2")); log != "a(1)b(2)a(2)" {
println("in select5, expecting a(1)b(2)a(2), got ", log)
err++
}
log = ""
if a("3")(b("4"))(b("5")); log != "a(3)b(4)a(4)b(5)a(5)" {
println("in select5, expecting a(3)b(4)a(4)b(5)a(5), got ", log)
err++
}
log = ""
var i I = T1(0)
if i.a("6").a(i.b("7")).a(i.b("8")).a(i.b("9")); log != "a(6)b(7)a(7)b(8)a(8)b(9)a(9)" {
println("in select5, expecting a(6)ba(7)ba(8)ba(9), got", log)
err++
}
log = ""
}
if err > 0 {
panic("fail")
}
}