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// Copyright 2009 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.
package obj
import (
"fmt"
"os"
"strings"
)
// go-specific code shared across loaders (5l, 6l, 8l).
var (
framepointer_enabled int
Fieldtrack_enabled int
Preemptibleloops_enabled int
)
// Toolchain experiments.
// These are controlled by the GOEXPERIMENT environment
// variable recorded when the toolchain is built.
// This list is also known to cmd/gc.
var exper = []struct {
name string
val *int
}{
{"fieldtrack", &Fieldtrack_enabled},
{"framepointer", &framepointer_enabled},
{"preemptibleloops", &Preemptibleloops_enabled},
}
func addexp(s string) {
// Could do general integer parsing here, but the runtime copy doesn't yet.
v := 1
name := s
if len(name) > 2 && name[:2] == "no" {
v = 0
name = name[2:]
}
for i := 0; i < len(exper); i++ {
if exper[i].name == name {
if exper[i].val != nil {
*exper[i].val = v
}
return
}
}
fmt.Printf("unknown experiment %s\n", s)
os.Exit(2)
}
func init() {
framepointer_enabled = 1 // default
for _, f := range strings.Split(goexperiment, ",") {
if f != "" {
addexp(f)
}
}
}
func Framepointer_enabled(goos, goarch string) bool {
return framepointer_enabled != 0 && goarch == "amd64" && goos != "nacl"
}
func Nopout(p *Prog) {
p.As = ANOP
p.Scond = 0
p.From = Addr{}
p.From3 = nil
p.Reg = 0
p.To = Addr{}
}
func Expstring() string {
buf := "X"
for i := range exper {
if *exper[i].val != 0 {
buf += "," + exper[i].name
}
}
if buf == "X" {
buf += ",none"
}
return "X:" + buf[2:]
}
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