runtime,cmd/link: include GOEXPERIMENTs in runtime.Version(), "go version X"

This adds the set of GOEXPERIMENTs to the build version if it differs
from the default set of experiments. This exposes the experiment
settings via runtime.Version() and "go version <binary>".

Change-Id: I143dbbc50f66a4cf175469199974e18848075af6
Reviewed-on: https://go-review.googlesource.com/c/go/+/307820
Trust: Austin Clements <austin@google.com>
Run-TryBot: Austin Clements <austin@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Matthew Dempsky <mdempsky@google.com>

diff --git a/src/cmd/dist/buildruntime.go b/src/cmd/dist/buildruntime.go
index e0a101a3532428a2d94fa2ae89edf005784b47c8..3ef551e187e9b11131f060c01b6b29ceeecdb313 100644 (file)
--- a/src/cmd/dist/buildruntime.go
+++ b/src/cmd/dist/buildruntime.go
@@ -19,7 +19,6 @@ import (
 //
 //     package sys
 //
-//     const TheVersion = <version>
 //     const StackGuardMultiplier = <multiplier value>
 //
 func mkzversion(dir, file string) {
@@ -28,7 +27,6 @@ func mkzversion(dir, file string) {
        fmt.Fprintln(&buf)
        fmt.Fprintf(&buf, "package sys\n")
        fmt.Fprintln(&buf)
-       fmt.Fprintf(&buf, "const TheVersion = `%s`\n", findgoversion())
        fmt.Fprintf(&buf, "const StackGuardMultiplierDefault = %d\n", stackGuardMultiplierDefault())
 
        writefile(buf.String(), file, writeSkipSame)

diff --git a/src/cmd/go/testdata/script/version_goexperiment.txt b/src/cmd/go/testdata/script/version_goexperiment.txt
new file mode 100644 (file)
index 0000000..4b165eb
--- /dev/null
+++ b/src/cmd/go/testdata/script/version_goexperiment.txt
@@ -0,0 +1,16 @@
+# Test that experiments appear in "go version <binary>"
+
+# This test requires rebuilding the runtime, which takes a while.
+[short] skip
+
+env GOEXPERIMENT=fieldtrack
+go build -o main$GOEXE version.go
+go version main$GOEXE
+stdout 'X:fieldtrack$'
+exec ./main$GOEXE
+stderr 'X:fieldtrack$'
+
+-- version.go --
+package main
+import "runtime"
+func main() { println(runtime.Version()) }

diff --git a/src/cmd/link/internal/ld/main.go b/src/cmd/link/internal/ld/main.go
index 95c89f813be8f0fc7c0d6a56de19977065b152a9..8631cf2939601537892d1cd249ed81da698560e8 100644 (file)
--- a/src/cmd/link/internal/ld/main.go
+++ b/src/cmd/link/internal/ld/main.go
@@ -118,6 +118,12 @@ func Main(arch *sys.Arch, theArch Arch) {
        addstrdata1(ctxt, "runtime.defaultGOROOT="+final)
        addstrdata1(ctxt, "cmd/internal/objabi.defaultGOROOT="+final)
 
+       buildVersion := objabi.Version
+       if goexperiment := objabi.GOEXPERIMENT(); goexperiment != "" {
+               buildVersion += " X:" + goexperiment
+       }
+       addstrdata1(ctxt, "runtime.buildVersion="+buildVersion)
+
        // TODO(matloob): define these above and then check flag values here
        if ctxt.Arch.Family == sys.AMD64 && objabi.GOOS == "plan9" {
                flag.BoolVar(&flag8, "8", false, "use 64-bit addresses in symbol table")

diff --git a/src/internal/goexperiment/flags.go b/src/internal/goexperiment/flags.go
index 1c513d5a709a8346d8b6be944d9af4207e85806d..4803fabe28e87d024b5c97dc8d4c4fe668b43af1 100644 (file)
--- a/src/internal/goexperiment/flags.go
+++ b/src/internal/goexperiment/flags.go
@@ -26,6 +26,9 @@
 // In the toolchain, the set of experiments enabled for the current
 // build should be accessed via objabi.Experiment.
 //
+// The set of experiments is included in the output of runtime.Version()
+// and "go version <binary>" if it differs from the default experiments.
+//
 // For the set of experiments supported by the current toolchain, see
 // go doc internal/experiment.Flags.
 package goexperiment

diff --git a/src/runtime/extern.go b/src/runtime/extern.go
index b73d68428fe988304ad7730c3a0c32a9ae2c7d07..48e1e6603b7aeb179bdf627c801f91665e3106b0 100644 (file)
--- a/src/runtime/extern.go
+++ b/src/runtime/extern.go
@@ -240,11 +240,21 @@ func GOROOT() string {
        return defaultGOROOT
 }
 
+// buildVersion is the Go tree's version string at build time.
+//
+// If any GOEXPERIMENTs are set to non-default values, it will include
+// "X:<GOEXPERIMENT>".
+//
+// This is set by the linker.
+//
+// This is accessed by "go version <binary>".
+var buildVersion string
+
 // Version returns the Go tree's version string.
 // It is either the commit hash and date at the time of the build or,
 // when possible, a release tag like "go1.3".
 func Version() string {
-       return sys.TheVersion
+       return buildVersion
 }
 
 // GOOS is the running program's operating system target:

diff --git a/src/runtime/proc.go b/src/runtime/proc.go
index 35a3f9ca199a6b07e3d23c728c44d4d8149ff441..d545a143a036fc5daa7b691067775fe12a22848d 100644 (file)
--- a/src/runtime/proc.go
+++ b/src/runtime/proc.go
@@ -12,8 +12,6 @@ import (
        "unsafe"
 )
 
-var buildVersion = sys.TheVersion
-
 // set using cmd/go/internal/modload.ModInfoProg
 var modinfo string