cmd: move GOEXPERIMENT knob from make.bash to cmd/go

This CL changes GOEXPERIMENT to act like other GO[CONFIG] environment
variables. Namely, that it can be set at make.bash time to provide a
default value used by the toolchain, but then can be manually set when
running either cmd/go or the individual tools (compiler, assembler,
linker).

For example, it's now possible to test rsc.io/tmp/fieldtrack by simply
running:

GOEXPERIMENT=fieldtrack go test -gcflags=-l rsc.io/tmp/fieldtrack \
  -ldflags=-k=rsc.io/tmp/fieldtrack.tracked

without needing to re-run make.bash. (-gcflags=-l is needed because
the compiler's inlining abilities have improved, so calling a function
with a for loop is no longer sufficient to suppress inlining.)

Fixes #42681.

Change-Id: I2cf8995d5d0d05f6785a2ee1d3b54b2cfb3331ca
Reviewed-on: https://go-review.googlesource.com/c/go/+/300991
Trust: Matthew Dempsky <mdempsky@google.com>
Run-TryBot: Matthew Dempsky <mdempsky@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
This commit is contained in:
Matthew Dempsky 2020-12-23 19:49:39 -08:00
parent b3896fc331
commit 7fc638d6f1
12 changed files with 51 additions and 48 deletions

View file

@ -21,17 +21,18 @@ func envOr(key, value string) string {
var (
defaultGOROOT string // set by linker
GOROOT = envOr("GOROOT", defaultGOROOT)
GOARCH = envOr("GOARCH", defaultGOARCH)
GOOS = envOr("GOOS", defaultGOOS)
GO386 = envOr("GO386", defaultGO386)
GOARM = goarm()
GOMIPS = gomips()
GOMIPS64 = gomips64()
GOPPC64 = goppc64()
GOWASM = gowasm()
GO_LDSO = defaultGO_LDSO
Version = version
GOROOT = envOr("GOROOT", defaultGOROOT)
GOARCH = envOr("GOARCH", defaultGOARCH)
GOOS = envOr("GOOS", defaultGOOS)
GOEXPERIMENT = envOr("GOEXPERIMENT", defaultGOEXPERIMENT)
GO386 = envOr("GO386", defaultGO386)
GOARM = goarm()
GOMIPS = gomips()
GOMIPS64 = gomips64()
GOPPC64 = goppc64()
GOWASM = gowasm()
GO_LDSO = defaultGO_LDSO
Version = version
)
const (
@ -124,7 +125,7 @@ func Getgoextlinkenabled() string {
}
func init() {
for _, f := range strings.Split(goexperiment, ",") {
for _, f := range strings.Split(GOEXPERIMENT, ",") {
if f != "" {
addexp(f)
}