cmd/go: initialize in get before loading packages

Otherwise the packages will not pick up the way that -installsuffix is
changed by -buildmode and -race.

Fixes #20512.

Change-Id: Ieca32c958a531beb6331dff30d7e9a4998867dbb
Reviewed-on: https://go-review.googlesource.com/44630
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>

src/cmd/go/go_test.go

@@ -3159,6 +3159,20 @@ func TestGoGetUpdate(t *testing.T) {
 	tg.run("get", "-d", "-u", "github.com/rsc/go-get-issue-9224-cmd")
 }
 
+// Issue #20512.
+func TestGoGetRace(t *testing.T) {
+	testenv.MustHaveExternalNetwork(t)
+	if !canRace {
+		t.Skip("skipping because race detector not supported")
+	}
+
+	tg := testgo(t)
+	defer tg.cleanup()
+	tg.makeTempdir()
+	tg.setenv("GOPATH", tg.path("."))
+	tg.run("get", "-race", "github.com/rsc/go-get-issue-9224-cmd")
+}
+
 func TestGoGetDomainRoot(t *testing.T) {
 	// golang.org/issue/9357.
 	// go get foo.io (not foo.io/subdir) was not working consistently.

src/cmd/go/internal/get/get.go

@@ -90,6 +90,9 @@ func init() {
 }
 
 func runGet(cmd *base.Command, args []string) {
+	work.InstrumentInit()
+	work.BuildModeInit()
+
 	if *getF && !*getU {
 		base.Fatalf("go get: cannot use -f flag without -u")
 	}

src/cmd/go/internal/work/build.go

@@ -545,6 +545,8 @@ func libname(args []string, pkgs []*load.Package) (string, error) {
 }
 
 func runInstall(cmd *base.Command, args []string) {
+	InstrumentInit()
+	BuildModeInit()
 	InstallPackages(args, false)
 }
 
@@ -553,8 +555,6 @@ func InstallPackages(args []string, forGet bool) {
 		base.Fatalf("cannot install, GOBIN must be an absolute path")
 	}
 
-	InstrumentInit()
-	BuildModeInit()
 	pkgs := pkgsFilter(load.PackagesForBuild(args))
 
 	for _, p := range pkgs {