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cmd/api: eliminate duplicate package import work

On my Mac, cuts the API checks from 15 seconds to 6 seconds.
Also clean up some tag confusion: go run list-of-files ignores tags.

R=bradfitz, gri
CC=golang-dev
https://golang.org/cl/12699048
This commit is contained in:
Russ Cox 2013-08-09 18:44:00 -04:00
parent 1f25f5ad48
commit b78410bda1
4 changed files with 60 additions and 6 deletions

View File

@ -1,9 +1,9 @@
// +build api_tool
// Copyright 2011 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.
// +build api_tool
// Binary api computes the exported API of a set of Go packages.
package main
@ -387,6 +387,38 @@ func contains(list []string, s string) bool {
return false
}
var (
pkgCache = map[string]*types.Package{} // map tagKey to package
pkgTags = map[string][]string{} // map import dir to list of relevant tags
)
// tagKey returns the tag-based key to use in the pkgCache.
// It is a comma-separated string; the first part is dir, the rest tags.
// The satisfied tags are derived from context but only those that
// matter (the ones listed in the tags argument) are used.
// The tags list, which came from go/build's Package.AllTags,
// is known to be sorted.
func tagKey(dir string, context *build.Context, tags []string) string {
ctags := map[string]bool{
context.GOOS: true,
context.GOARCH: true,
}
if context.CgoEnabled {
ctags["cgo"] = true
}
for _, tag := range context.BuildTags {
ctags[tag] = true
}
// TODO: ReleaseTags (need to load default)
key := dir
for _, tag := range tags {
if ctags[tag] {
key += "," + tag
}
}
return key
}
// Importing is a sentinel taking the place in Walker.imported
// for a package that is in the process of being imported.
var importing types.Package
@ -411,6 +443,19 @@ func (w *Walker) Import(name string) (pkg *types.Package) {
if context == nil {
context = &build.Default
}
// Look in cache.
// If we've already done an import with the same set
// of relevant tags, reuse the result.
var key string
if tags, ok := pkgTags[dir]; ok {
key = tagKey(dir, context, tags)
if pkg := pkgCache[key]; pkg != nil {
w.imported[name] = pkg
return pkg
}
}
info, err := context.ImportDir(dir, 0)
if err != nil {
if _, nogo := err.(*build.NoGoError); nogo {
@ -418,6 +463,13 @@ func (w *Walker) Import(name string) (pkg *types.Package) {
}
log.Fatalf("pkg %q, dir %q: ScanDir: %v", name, dir, err)
}
// Save tags list first time we see a directory.
if _, ok := pkgTags[dir]; !ok {
pkgTags[dir] = info.AllTags
key = tagKey(dir, context, info.AllTags)
}
filenames := append(append([]string{}, info.GoFiles...), info.CgoFiles...)
// Certain files only exist when building for the specified context.
@ -463,6 +515,8 @@ func (w *Walker) Import(name string) (pkg *types.Package) {
log.Fatalf("error typechecking package %s: %s (%s)", name, err, ctxt)
}
pkgCache[key] = pkg
w.imported[name] = pkg
return
}

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@ -1,9 +1,9 @@
// +build from_src_run
// Copyright 2013 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.
// +build ignore
// The run program is invoked via "go run" from src/run.bash or
// src/run.bat conditionally builds and runs the cmd/api tool.
//

View File

@ -182,7 +182,7 @@ time go run run.go || exit 1
echo
echo '# Checking API compatibility.'
go run --tags=from_src_run $GOROOT/src/cmd/api/run.go
time go run $GOROOT/src/cmd/api/run.go
echo
echo ALL TESTS PASSED

View File

@ -121,7 +121,7 @@ set GOMAXPROCS=%OLDGOMAXPROCS%
set OLDGOMAXPROCS=
echo # Checking API compatibility.
go run --tags=from_src_run "%GOROOT%\src\cmd\api\run.go"
go run "%GOROOT%\src\cmd\api\run.go"
if errorlevel 1 goto fail
echo.