Current File : //usr/local/go119/src/cmd/vendor/golang.org/x/tools/go/analysis/unitchecker/unitchecker.go
// Copyright 2018 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.
// The unitchecker package defines the main function for an analysis
// driver that analyzes a single compilation unit during a build.
// It is invoked by a build system such as "go vet":
//
// $ go vet -vettool=$(which vet)
//
// It supports the following command-line protocol:
//
// -V=full describe executable (to the build tool)
// -flags describe flags (to the build tool)
// foo.cfg description of compilation unit (from the build tool)
//
// This package does not depend on go/packages.
// If you need a standalone tool, use multichecker,
// which supports this mode but can also load packages
// from source using go/packages.
package unitchecker
// TODO(adonovan):
// - with gccgo, go build does not build standard library,
// so we will not get to analyze it. Yet we must in order
// to create base facts for, say, the fmt package for the
// printf checker.
import (
"encoding/gob"
"encoding/json"
"flag"
"fmt"
"go/ast"
"go/build"
"go/importer"
"go/parser"
"go/token"
"go/types"
"io"
"io/ioutil"
"log"
"os"
"path/filepath"
"reflect"
"sort"
"strings"
"sync"
"time"
"golang.org/x/tools/go/analysis"
"golang.org/x/tools/go/analysis/internal/analysisflags"
"golang.org/x/tools/go/analysis/internal/facts"
"golang.org/x/tools/internal/typeparams"
)
// A Config describes a compilation unit to be analyzed.
// It is provided to the tool in a JSON-encoded file
// whose name ends with ".cfg".
type Config struct {
ID string // e.g. "fmt [fmt.test]"
Compiler string
Dir string
ImportPath string
GoFiles []string
NonGoFiles []string
IgnoredFiles []string
ImportMap map[string]string
PackageFile map[string]string
Standard map[string]bool
PackageVetx map[string]string
VetxOnly bool
VetxOutput string
SucceedOnTypecheckFailure bool
}
// Main is the main function of a vet-like analysis tool that must be
// invoked by a build system to analyze a single package.
//
// The protocol required by 'go vet -vettool=...' is that the tool must support:
//
// -flags describe flags in JSON
// -V=full describe executable for build caching
// foo.cfg perform separate modular analyze on the single
// unit described by a JSON config file foo.cfg.
func Main(analyzers ...*analysis.Analyzer) {
progname := filepath.Base(os.Args[0])
log.SetFlags(0)
log.SetPrefix(progname + ": ")
if err := analysis.Validate(analyzers); err != nil {
log.Fatal(err)
}
flag.Usage = func() {
fmt.Fprintf(os.Stderr, `%[1]s is a tool for static analysis of Go programs.
Usage of %[1]s:
%.16[1]s unit.cfg # execute analysis specified by config file
%.16[1]s help # general help, including listing analyzers and flags
%.16[1]s help name # help on specific analyzer and its flags
`, progname)
os.Exit(1)
}
analyzers = analysisflags.Parse(analyzers, true)
args := flag.Args()
if len(args) == 0 {
flag.Usage()
}
if args[0] == "help" {
analysisflags.Help(progname, analyzers, args[1:])
os.Exit(0)
}
if len(args) != 1 || !strings.HasSuffix(args[0], ".cfg") {
log.Fatalf(`invoking "go tool vet" directly is unsupported; use "go vet"`)
}
Run(args[0], analyzers)
}
// Run reads the *.cfg file, runs the analysis,
// and calls os.Exit with an appropriate error code.
// It assumes flags have already been set.
func Run(configFile string, analyzers []*analysis.Analyzer) {
cfg, err := readConfig(configFile)
if err != nil {
log.Fatal(err)
}
fset := token.NewFileSet()
results, err := run(fset, cfg, analyzers)
if err != nil {
log.Fatal(err)
}
// In VetxOnly mode, the analysis is run only for facts.
if !cfg.VetxOnly {
if analysisflags.JSON {
// JSON output
tree := make(analysisflags.JSONTree)
for _, res := range results {
tree.Add(fset, cfg.ID, res.a.Name, res.diagnostics, res.err)
}
tree.Print()
} else {
// plain text
exit := 0
for _, res := range results {
if res.err != nil {
log.Println(res.err)
exit = 1
}
}
for _, res := range results {
for _, diag := range res.diagnostics {
analysisflags.PrintPlain(fset, diag)
exit = 1
}
}
os.Exit(exit)
}
}
os.Exit(0)
}
func readConfig(filename string) (*Config, error) {
data, err := ioutil.ReadFile(filename)
if err != nil {
return nil, err
}
cfg := new(Config)
if err := json.Unmarshal(data, cfg); err != nil {
return nil, fmt.Errorf("cannot decode JSON config file %s: %v", filename, err)
}
if len(cfg.GoFiles) == 0 {
// The go command disallows packages with no files.
// The only exception is unsafe, but the go command
// doesn't call vet on it.
return nil, fmt.Errorf("package has no files: %s", cfg.ImportPath)
}
return cfg, nil
}
var importerForCompiler = func(_ *token.FileSet, compiler string, lookup importer.Lookup) types.Importer {
// broken legacy implementation (https://golang.org/issue/28995)
return importer.For(compiler, lookup)
}
func run(fset *token.FileSet, cfg *Config, analyzers []*analysis.Analyzer) ([]result, error) {
// Load, parse, typecheck.
var files []*ast.File
for _, name := range cfg.GoFiles {
f, err := parser.ParseFile(fset, name, nil, parser.ParseComments)
if err != nil {
if cfg.SucceedOnTypecheckFailure {
// Silently succeed; let the compiler
// report parse errors.
err = nil
}
return nil, err
}
files = append(files, f)
}
compilerImporter := importerForCompiler(fset, cfg.Compiler, func(path string) (io.ReadCloser, error) {
// path is a resolved package path, not an import path.
file, ok := cfg.PackageFile[path]
if !ok {
if cfg.Compiler == "gccgo" && cfg.Standard[path] {
return nil, nil // fall back to default gccgo lookup
}
return nil, fmt.Errorf("no package file for %q", path)
}
return os.Open(file)
})
importer := importerFunc(func(importPath string) (*types.Package, error) {
path, ok := cfg.ImportMap[importPath] // resolve vendoring, etc
if !ok {
return nil, fmt.Errorf("can't resolve import %q", path)
}
return compilerImporter.Import(path)
})
tc := &types.Config{
Importer: importer,
Sizes: types.SizesFor("gc", build.Default.GOARCH), // assume gccgo ≡ gc?
}
info := &types.Info{
Types: make(map[ast.Expr]types.TypeAndValue),
Defs: make(map[*ast.Ident]types.Object),
Uses: make(map[*ast.Ident]types.Object),
Implicits: make(map[ast.Node]types.Object),
Scopes: make(map[ast.Node]*types.Scope),
Selections: make(map[*ast.SelectorExpr]*types.Selection),
}
typeparams.InitInstanceInfo(info)
pkg, err := tc.Check(cfg.ImportPath, fset, files, info)
if err != nil {
if cfg.SucceedOnTypecheckFailure {
// Silently succeed; let the compiler
// report type errors.
err = nil
}
return nil, err
}
// Register fact types with gob.
// In VetxOnly mode, analyzers are only for their facts,
// so we can skip any analysis that neither produces facts
// nor depends on any analysis that produces facts.
// Also build a map to hold working state and result.
type action struct {
once sync.Once
result interface{}
err error
usesFacts bool // (transitively uses)
diagnostics []analysis.Diagnostic
}
actions := make(map[*analysis.Analyzer]*action)
var registerFacts func(a *analysis.Analyzer) bool
registerFacts = func(a *analysis.Analyzer) bool {
act, ok := actions[a]
if !ok {
act = new(action)
var usesFacts bool
for _, f := range a.FactTypes {
usesFacts = true
gob.Register(f)
}
for _, req := range a.Requires {
if registerFacts(req) {
usesFacts = true
}
}
act.usesFacts = usesFacts
actions[a] = act
}
return act.usesFacts
}
var filtered []*analysis.Analyzer
for _, a := range analyzers {
if registerFacts(a) || !cfg.VetxOnly {
filtered = append(filtered, a)
}
}
analyzers = filtered
// Read facts from imported packages.
read := func(path string) ([]byte, error) {
if vetx, ok := cfg.PackageVetx[path]; ok {
return ioutil.ReadFile(vetx)
}
return nil, nil // no .vetx file, no facts
}
facts, err := facts.Decode(pkg, read)
if err != nil {
return nil, err
}
// In parallel, execute the DAG of analyzers.
var exec func(a *analysis.Analyzer) *action
var execAll func(analyzers []*analysis.Analyzer)
exec = func(a *analysis.Analyzer) *action {
act := actions[a]
act.once.Do(func() {
execAll(a.Requires) // prefetch dependencies in parallel
// The inputs to this analysis are the
// results of its prerequisites.
inputs := make(map[*analysis.Analyzer]interface{})
var failed []string
for _, req := range a.Requires {
reqact := exec(req)
if reqact.err != nil {
failed = append(failed, req.String())
continue
}
inputs[req] = reqact.result
}
// Report an error if any dependency failed.
if failed != nil {
sort.Strings(failed)
act.err = fmt.Errorf("failed prerequisites: %s", strings.Join(failed, ", "))
return
}
factFilter := make(map[reflect.Type]bool)
for _, f := range a.FactTypes {
factFilter[reflect.TypeOf(f)] = true
}
pass := &analysis.Pass{
Analyzer: a,
Fset: fset,
Files: files,
OtherFiles: cfg.NonGoFiles,
IgnoredFiles: cfg.IgnoredFiles,
Pkg: pkg,
TypesInfo: info,
TypesSizes: tc.Sizes,
ResultOf: inputs,
Report: func(d analysis.Diagnostic) { act.diagnostics = append(act.diagnostics, d) },
ImportObjectFact: facts.ImportObjectFact,
ExportObjectFact: facts.ExportObjectFact,
AllObjectFacts: func() []analysis.ObjectFact { return facts.AllObjectFacts(factFilter) },
ImportPackageFact: facts.ImportPackageFact,
ExportPackageFact: facts.ExportPackageFact,
AllPackageFacts: func() []analysis.PackageFact { return facts.AllPackageFacts(factFilter) },
}
t0 := time.Now()
act.result, act.err = a.Run(pass)
if false {
log.Printf("analysis %s = %s", pass, time.Since(t0))
}
})
return act
}
execAll = func(analyzers []*analysis.Analyzer) {
var wg sync.WaitGroup
for _, a := range analyzers {
wg.Add(1)
go func(a *analysis.Analyzer) {
_ = exec(a)
wg.Done()
}(a)
}
wg.Wait()
}
execAll(analyzers)
// Return diagnostics and errors from root analyzers.
results := make([]result, len(analyzers))
for i, a := range analyzers {
act := actions[a]
results[i].a = a
results[i].err = act.err
results[i].diagnostics = act.diagnostics
}
data := facts.Encode()
if err := ioutil.WriteFile(cfg.VetxOutput, data, 0666); err != nil {
return nil, fmt.Errorf("failed to write analysis facts: %v", err)
}
return results, nil
}
type result struct {
a *analysis.Analyzer
diagnostics []analysis.Diagnostic
err error
}
type importerFunc func(path string) (*types.Package, error)
func (f importerFunc) Import(path string) (*types.Package, error) { return f(path) }
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