gvisor/tools/checklocks/annotations.go

133 lines
4.1 KiB
Go

// Copyright 2020 The gVisor Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package checklocks
import (
"fmt"
"go/token"
"strconv"
"strings"
)
const (
checkLocksAnnotation = "// +checklocks:"
checkLocksAnnotationRead = "// +checklocksread:"
checkLocksAcquires = "// +checklocksacquire:"
checkLocksAcquiresRead = "// +checklocksacquireread:"
checkLocksReleases = "// +checklocksrelease:"
checkLocksReleasesRead = "// +checklocksreleaseread:"
checkLocksIgnore = "// +checklocksignore"
checkLocksForce = "// +checklocksforce"
checkLocksFail = "// +checklocksfail"
checkAtomicAnnotation = "// +checkatomic"
)
// failData indicates an expected failure.
type failData struct {
pos token.Pos
count int
seen int
}
// positionKey is a simple position string.
type positionKey string
// positionKey converts from a token.Pos to a key we can use to track failures
// as the position of the failure annotation is not the same as the position of
// the actual failure (different column/offsets). Hence we ignore these fields
// and only use the file/line numbers to track failures.
func (pc *passContext) positionKey(pos token.Pos) positionKey {
position := pc.pass.Fset.Position(pos)
return positionKey(fmt.Sprintf("%s:%d", position.Filename, position.Line))
}
// addFailures adds an expected failure.
func (pc *passContext) addFailures(pos token.Pos, s string) {
count := 1
if len(s) > 0 && s[0] == ':' {
parsedCount, err := strconv.Atoi(s[1:])
if err != nil {
pc.pass.Reportf(pos, "unable to parse failure annotation %q: %v", s[1:], err)
return
}
count = parsedCount
}
pc.failures[pc.positionKey(pos)] = &failData{
pos: pos,
count: count,
}
}
// addExemption adds an exemption.
func (pc *passContext) addExemption(pos token.Pos) {
pc.exemptions[pc.positionKey(pos)] = struct{}{}
}
// addForce adds a force annotation.
func (pc *passContext) addForce(pos token.Pos) {
pc.forced[pc.positionKey(pos)] = struct{}{}
}
// maybeFail checks a potential failure against a specific failure map.
func (pc *passContext) maybeFail(pos token.Pos, fmtStr string, args ...interface{}) {
if fd, ok := pc.failures[pc.positionKey(pos)]; ok {
fd.seen++
return
}
if _, ok := pc.exemptions[pc.positionKey(pos)]; ok {
return // Ignored, not counted.
}
pc.pass.Reportf(pos, fmtStr, args...)
}
// checkFailure checks for the expected failure counts.
func (pc *passContext) checkFailures() {
for _, fd := range pc.failures {
if fd.count != fd.seen {
// We are missing expect failures, report as much as possible.
pc.pass.Reportf(fd.pos, "got %d failures, want %d failures", fd.seen, fd.count)
}
}
}
// extractAnnotations extracts annotations from text.
func (pc *passContext) extractAnnotations(s string, fns map[string]func(p string)) {
for prefix, fn := range fns {
if strings.HasPrefix(s, prefix) {
fn(s[len(prefix):])
}
}
}
// extractLineFailures extracts all line-based exceptions.
//
// Note that this applies only to individual line exemptions, and does not
// consider function-wide exemptions, or specific field exemptions, which are
// extracted separately as part of the saved facts for those objects.
func (pc *passContext) extractLineFailures() {
for _, f := range pc.pass.Files {
for _, cg := range f.Comments {
for _, c := range cg.List {
pc.extractAnnotations(c.Text, map[string]func(string){
checkLocksFail: func(p string) { pc.addFailures(c.Pos(), p) },
checkLocksIgnore: func(string) { pc.addExemption(c.Pos()) },
checkLocksForce: func(string) { pc.addForce(c.Pos()) },
})
}
}
}
}