cmd/distpack: remove more tools from packaged distribution

The "doc", "fix", and "covdata" tools invoked by the go command are not
needed for builds. Instead of invoking them directly using the installed
binary in the tool directory, use "go tool" to run them, building them
if needed. We can then stop distributing those tools in the
distribution.

covdata is used in tests and can form part of a cached test result, but
test results don't have the same requirements as build outputs to be
completely determined by the action id. We already don't include a
toolid for the covdata tool in the action id for a test run. The more
principled way to do things would be to load the covdata package,
create the actions to build it, and then depend on the output of
that action from the the test action and use that as the covdata tool.
For now, it's probably not worth the effort, but, in the future, if we
wanted to build a tool like cgo as needed, it would be best to build it
in the same action graph. That would introduce a whole bunch of complexity
because we'd need to build the tool in the host configuration, and all
the configuration parameters are global.

For #71867

Change-Id: Id9bbbb5c169296f66c072949f9da552424ecfa2f
Reviewed-on: https://go-review.googlesource.com/c/go/+/673119
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
Reviewed-by: Michael Matloob <matloob@google.com>

Author: matloob

src/cmd/distpack/pack.go

@@ -169,7 +169,8 @@ func main() {
 			}
 			// Inside pkg/tool/$GOOS_$GOARCH, discard helper tools, and tools not needed for builds.
 			switch strings.TrimSuffix(path.Base(name), ".exe") {
-			case "addr2line", "api", "buildid", "dist", "distpack", "metadata", "nm", "objdump", "pprof", "test2json", "trace":
+			case "addr2line", "api", "buildid", "covdata", "dist", "distpack", "doc", "fix",
+				"metadata", "nm", "objdump", "pprof", "test2json", "trace":
 				return false
 			}
 		}

src/cmd/go/internal/doc/doc.go

@@ -9,6 +9,7 @@ import (
 	"cmd/go/internal/base"
 	"cmd/go/internal/cfg"
 	"context"
+	"path/filepath"
 )
 
 var CmdDoc = &base.Command{
@@ -130,5 +131,5 @@ Flags:
 }
 
 func runDoc(ctx context.Context, cmd *base.Command, args []string) {
-	base.Run(cfg.BuildToolexec, base.Tool("doc"), args)
+	base.Run(cfg.BuildToolexec, filepath.Join(cfg.GOROOTbin, "go"), "tool", "doc", args)
 }

src/cmd/go/internal/fix/fix.go

@@ -16,6 +16,7 @@ import (
 	"fmt"
 	"go/build"
 	"os"
+	"path/filepath"
 )
 
 var CmdFix = &base.Command{
@@ -80,6 +81,6 @@ func runFix(ctx context.Context, cmd *base.Command, args []string) {
 		if *fixes != "" {
 			fixArg = []string{"-r=" + *fixes}
 		}
-		base.Run(str.StringList(cfg.BuildToolexec, base.Tool("fix"), "-go="+goVersion, fixArg, files))
+		base.Run(str.StringList(cfg.BuildToolexec, filepath.Join(cfg.GOROOTbin, "go"), "tool", "fix", "-go="+goVersion, fixArg, files))
 	}
 }

src/cmd/go/internal/work/cover.go

@@ -7,7 +7,6 @@
 package work
 
 import (
-	"cmd/go/internal/base"
 	"cmd/go/internal/cfg"
 	"cmd/go/internal/str"
 	"cmd/internal/cov/covcmd"
@@ -25,7 +24,7 @@ import (
 func (b *Builder) CovData(a *Action, cmdargs ...any) ([]byte, error) {
 	cmdline := str.StringList(cmdargs...)
 	args := append([]string{}, cfg.BuildToolexec...)
-	args = append(args, base.Tool("covdata"))
+	args = append(args, "go", "tool", "covdata")
 	args = append(args, cmdline...)
 	return b.Shell(a).runOut(a.Objdir, nil, args)
 }