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// Copyright 2019 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.
package cache
import (
"context"
"fmt"
"go/ast"
"go/types"
"reflect"
"sort"
"sync"
"golang.org/x/sync/errgroup"
"golang.org/x/tools/go/analysis"
"golang.org/x/tools/internal/analysisinternal"
"golang.org/x/tools/internal/event"
"golang.org/x/tools/internal/lsp/debug/tag"
"golang.org/x/tools/internal/lsp/source"
"golang.org/x/tools/internal/memoize"
"golang.org/x/tools/internal/span"
errors "golang.org/x/xerrors"
)
func (s *snapshot) Analyze(ctx context.Context, id string, analyzers []*source.Analyzer) ([]*source.Diagnostic, error) {
var roots []*actionHandle
for _, a := range analyzers {
if !a.IsEnabled(s.view) {
continue
}
ah, err := s.actionHandle(ctx, PackageID(id), a.Analyzer)
if err != nil {
return nil, err
}
roots = append(roots, ah)
}
// Check if the context has been canceled before running the analyses.
if ctx.Err() != nil {
return nil, ctx.Err()
}
var results []*source.Diagnostic
for _, ah := range roots {
diagnostics, _, err := ah.analyze(ctx, s)
if err != nil {
return nil, err
}
results = append(results, diagnostics...)
}
return results, nil
}
type actionHandleKey string
// An action represents one unit of analysis work: the application of
// one analysis to one package. Actions form a DAG, both within a
// package (as different analyzers are applied, either in sequence or
// parallel), and across packages (as dependencies are analyzed).
type actionHandle struct {
handle *memoize.Handle
analyzer *analysis.Analyzer
pkg *pkg
}
type actionData struct {
diagnostics []*source.Diagnostic
result interface{}
objectFacts map[objectFactKey]analysis.Fact
packageFacts map[packageFactKey]analysis.Fact
err error
}
type objectFactKey struct {
obj types.Object
typ reflect.Type
}
type packageFactKey struct {
pkg *types.Package
typ reflect.Type
}
func (s *snapshot) actionHandle(ctx context.Context, id PackageID, a *analysis.Analyzer) (*actionHandle, error) {
ph, err := s.buildPackageHandle(ctx, id, source.ParseFull)
if err != nil {
return nil, err
}
act := s.getActionHandle(id, ph.mode, a)
if act != nil {
return act, nil
}
if len(ph.key) == 0 {
return nil, errors.Errorf("actionHandle: no key for package %s", id)
}
pkg, err := ph.check(ctx, s)
if err != nil {
return nil, err
}
act = &actionHandle{
analyzer: a,
pkg: pkg,
}
var deps []*actionHandle
// Add a dependency on each required analyzers.
for _, req := range a.Requires {
reqActionHandle, err := s.actionHandle(ctx, id, req)
if err != nil {
return nil, err
}
deps = append(deps, reqActionHandle)
}
// TODO(golang/go#35089): Re-enable this when we doesn't use ParseExported
// mode for dependencies. In the meantime, disable analysis for dependencies,
// since we don't get anything useful out of it.
if false {
// An analysis that consumes/produces facts
// must run on the package's dependencies too.
if len(a.FactTypes) > 0 {
importIDs := make([]string, 0, len(ph.m.Deps))
for _, importID := range ph.m.Deps {
importIDs = append(importIDs, string(importID))
}
sort.Strings(importIDs) // for determinism
for _, importID := range importIDs {
depActionHandle, err := s.actionHandle(ctx, PackageID(importID), a)
if err != nil {
return nil, err
}
deps = append(deps, depActionHandle)
}
}
}
h := s.generation.Bind(buildActionKey(a, ph), func(ctx context.Context, arg memoize.Arg) interface{} {
snapshot := arg.(*snapshot)
// Analyze dependencies first.
results, err := execAll(ctx, snapshot, deps)
if err != nil {
return &actionData{
err: err,
}
}
return runAnalysis(ctx, snapshot, a, pkg, results)
}, nil)
act.handle = h
act = s.addActionHandle(act)
return act, nil
}
func (act *actionHandle) analyze(ctx context.Context, snapshot *snapshot) ([]*source.Diagnostic, interface{}, error) {
d, err := act.handle.Get(ctx, snapshot.generation, snapshot)
if err != nil {
return nil, nil, err
}
data, ok := d.(*actionData)
if !ok {
return nil, nil, errors.Errorf("unexpected type for %s:%s", act.pkg.ID(), act.analyzer.Name)
}
if data == nil {
return nil, nil, errors.Errorf("unexpected nil analysis for %s:%s", act.pkg.ID(), act.analyzer.Name)
}
return data.diagnostics, data.result, data.err
}
func buildActionKey(a *analysis.Analyzer, ph *packageHandle) actionHandleKey {
return actionHandleKey(hashContents([]byte(fmt.Sprintf("%p %s", a, string(ph.key)))))
}
func (act *actionHandle) String() string {
return fmt.Sprintf("%s@%s", act.analyzer, act.pkg.PkgPath())
}
func execAll(ctx context.Context, snapshot *snapshot, actions []*actionHandle) (map[*actionHandle]*actionData, error) {
var mu sync.Mutex
results := make(map[*actionHandle]*actionData)
g, ctx := errgroup.WithContext(ctx)
for _, act := range actions {
act := act
g.Go(func() error {
v, err := act.handle.Get(ctx, snapshot.generation, snapshot)
if err != nil {
return err
}
data, ok := v.(*actionData)
if !ok {
return errors.Errorf("unexpected type for %s: %T", act, v)
}
mu.Lock()
defer mu.Unlock()
results[act] = data
return nil
})
}
return results, g.Wait()
}
func runAnalysis(ctx context.Context, snapshot *snapshot, analyzer *analysis.Analyzer, pkg *pkg, deps map[*actionHandle]*actionData) (data *actionData) {
data = &actionData{
objectFacts: make(map[objectFactKey]analysis.Fact),
packageFacts: make(map[packageFactKey]analysis.Fact),
}
defer func() {
if r := recover(); r != nil {
data.err = errors.Errorf("analysis %s for package %s panicked: %v", analyzer.Name, pkg.PkgPath(), r)
}
}()
// Plumb the output values of the dependencies
// into the inputs of this action. Also facts.
inputs := make(map[*analysis.Analyzer]interface{})
for depHandle, depData := range deps {
if depHandle.pkg == pkg {
// Same package, different analysis (horizontal edge):
// in-memory outputs of prerequisite analyzers
// become inputs to this analysis pass.
inputs[depHandle.analyzer] = depData.result
} else if depHandle.analyzer == analyzer { // (always true)
// Same analysis, different package (vertical edge):
// serialized facts produced by prerequisite analysis
// become available to this analysis pass.
for key, fact := range depData.objectFacts {
// Filter out facts related to objects
// that are irrelevant downstream
// (equivalently: not in the compiler export data).
if !exportedFrom(key.obj, depHandle.pkg.types) {
continue
}
data.objectFacts[key] = fact
}
for key, fact := range depData.packageFacts {
// TODO: filter out facts that belong to
// packages not mentioned in the export data
// to prevent side channels.
data.packageFacts[key] = fact
}
}
}
var syntax []*ast.File
for _, cgf := range pkg.compiledGoFiles {
syntax = append(syntax, cgf.File)
}
var diagnostics []*analysis.Diagnostic
// Run the analysis.
pass := &analysis.Pass{
Analyzer: analyzer,
Fset: snapshot.FileSet(),
Files: syntax,
Pkg: pkg.GetTypes(),
TypesInfo: pkg.GetTypesInfo(),
TypesSizes: pkg.GetTypesSizes(),
ResultOf: inputs,
Report: func(d analysis.Diagnostic) {
// Prefix the diagnostic category with the analyzer's name.
if d.Category == "" {
d.Category = analyzer.Name
} else {
d.Category = analyzer.Name + "." + d.Category
}
diagnostics = append(diagnostics, &d)
},
ImportObjectFact: func(obj types.Object, ptr analysis.Fact) bool {
if obj == nil {
panic("nil object")
}
key := objectFactKey{obj, factType(ptr)}
if v, ok := data.objectFacts[key]; ok {
reflect.ValueOf(ptr).Elem().Set(reflect.ValueOf(v).Elem())
return true
}
return false
},
ExportObjectFact: func(obj types.Object, fact analysis.Fact) {
if obj.Pkg() != pkg.types {
panic(fmt.Sprintf("internal error: in analysis %s of package %s: Fact.Set(%s, %T): can't set facts on objects belonging another package",
analyzer, pkg.ID(), obj, fact))
}
key := objectFactKey{obj, factType(fact)}
data.objectFacts[key] = fact // clobber any existing entry
},
ImportPackageFact: func(pkg *types.Package, ptr analysis.Fact) bool {
if pkg == nil {
panic("nil package")
}
key := packageFactKey{pkg, factType(ptr)}
if v, ok := data.packageFacts[key]; ok {
reflect.ValueOf(ptr).Elem().Set(reflect.ValueOf(v).Elem())
return true
}
return false
},
ExportPackageFact: func(fact analysis.Fact) {
key := packageFactKey{pkg.types, factType(fact)}
data.packageFacts[key] = fact // clobber any existing entry
},
AllObjectFacts: func() []analysis.ObjectFact {
facts := make([]analysis.ObjectFact, 0, len(data.objectFacts))
for k := range data.objectFacts {
facts = append(facts, analysis.ObjectFact{Object: k.obj, Fact: data.objectFacts[k]})
}
return facts
},
AllPackageFacts: func() []analysis.PackageFact {
facts := make([]analysis.PackageFact, 0, len(data.packageFacts))
for k := range data.packageFacts {
facts = append(facts, analysis.PackageFact{Package: k.pkg, Fact: data.packageFacts[k]})
}
return facts
},
}
analysisinternal.SetTypeErrors(pass, pkg.typeErrors)
if pkg.IsIllTyped() {
data.err = errors.Errorf("analysis skipped due to errors in package")
return data
}
data.result, data.err = pass.Analyzer.Run(pass)
if data.err != nil {
return data
}
if got, want := reflect.TypeOf(data.result), pass.Analyzer.ResultType; got != want {
data.err = errors.Errorf(
"internal error: on package %s, analyzer %s returned a result of type %v, but declared ResultType %v",
pass.Pkg.Path(), pass.Analyzer, got, want)
return data
}
// disallow calls after Run
pass.ExportObjectFact = func(obj types.Object, fact analysis.Fact) {
panic(fmt.Sprintf("%s:%s: Pass.ExportObjectFact(%s, %T) called after Run", analyzer.Name, pkg.PkgPath(), obj, fact))
}
pass.ExportPackageFact = func(fact analysis.Fact) {
panic(fmt.Sprintf("%s:%s: Pass.ExportPackageFact(%T) called after Run", analyzer.Name, pkg.PkgPath(), fact))
}
for _, diag := range diagnostics {
srcDiags, err := analysisDiagnosticDiagnostics(snapshot, pkg, analyzer, diag)
if err != nil {
event.Error(ctx, "unable to compute analysis error position", err, tag.Category.Of(diag.Category), tag.Package.Of(pkg.ID()))
continue
}
if ctx.Err() != nil {
data.err = ctx.Err()
return data
}
data.diagnostics = append(data.diagnostics, srcDiags...)
}
return data
}
// exportedFrom reports whether obj may be visible to a package that imports pkg.
// This includes not just the exported members of pkg, but also unexported
// constants, types, fields, and methods, perhaps belonging to oether packages,
// that find there way into the API.
// This is an overapproximation of the more accurate approach used by
// gc export data, which walks the type graph, but it's much simpler.
//
// TODO(adonovan): do more accurate filtering by walking the type graph.
func exportedFrom(obj types.Object, pkg *types.Package) bool {
switch obj := obj.(type) {
case *types.Func:
return obj.Exported() && obj.Pkg() == pkg ||
obj.Type().(*types.Signature).Recv() != nil
case *types.Var:
return obj.Exported() && obj.Pkg() == pkg ||
obj.IsField()
case *types.TypeName, *types.Const:
return true
}
return false // Nil, Builtin, Label, or PkgName
}
func factType(fact analysis.Fact) reflect.Type {
t := reflect.TypeOf(fact)
if t.Kind() != reflect.Ptr {
panic(fmt.Sprintf("invalid Fact type: got %T, want pointer", t))
}
return t
}
func (s *snapshot) DiagnosePackage(ctx context.Context, spkg source.Package) (map[span.URI][]*source.Diagnostic, error) {
pkg := spkg.(*pkg)
// Apply type error analyzers. They augment type error diagnostics with their own fixes.
var analyzers []*source.Analyzer
for _, a := range s.View().Options().TypeErrorAnalyzers {
analyzers = append(analyzers, a)
}
var errorAnalyzerDiag []*source.Diagnostic
if pkg.HasTypeErrors() {
var err error
errorAnalyzerDiag, err = s.Analyze(ctx, pkg.ID(), analyzers)
if err != nil {
// Keep going: analysis failures should not block diagnostics.
event.Error(ctx, "type error analysis failed", err, tag.Package.Of(pkg.ID()))
}
}
diags := map[span.URI][]*source.Diagnostic{}
for _, diag := range pkg.diagnostics {
for _, eaDiag := range errorAnalyzerDiag {
if eaDiag.URI == diag.URI && eaDiag.Range == diag.Range && eaDiag.Message == diag.Message {
// Type error analyzers just add fixes and tags. Make a copy,
// since we don't own either, and overwrite.
// The analyzer itself can't do this merge because
// analysis.Diagnostic doesn't have all the fields, and Analyze
// can't because it doesn't have the type error, notably its code.
clone := *diag
clone.SuggestedFixes = eaDiag.SuggestedFixes
clone.Tags = eaDiag.Tags
clone.Analyzer = eaDiag.Analyzer
diag = &clone
}
}
diags[diag.URI] = append(diags[diag.URI], diag)
}
return diags, nil
}