97 lines
2.4 KiB
Go
97 lines
2.4 KiB
Go
// Copyright 2013 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Package atomic defines an Analyzer that checks for common mistakes
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// using the sync/atomic package.
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package atomic
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import (
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"go/ast"
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"go/token"
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"go/types"
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"golang.org/x/tools/go/analysis"
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"golang.org/x/tools/go/analysis/passes/inspect"
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"golang.org/x/tools/go/analysis/passes/internal/analysisutil"
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"golang.org/x/tools/go/ast/inspector"
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)
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const Doc = `check for common mistakes using the sync/atomic package
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The atomic checker looks for assignment statements of the form:
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x = atomic.AddUint64(&x, 1)
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which are not atomic.`
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var Analyzer = &analysis.Analyzer{
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Name: "atomic",
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Doc: Doc,
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Requires: []*analysis.Analyzer{inspect.Analyzer},
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RunDespiteErrors: true,
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Run: run,
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}
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func run(pass *analysis.Pass) (interface{}, error) {
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inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
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nodeFilter := []ast.Node{
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(*ast.AssignStmt)(nil),
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}
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inspect.Preorder(nodeFilter, func(node ast.Node) {
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n := node.(*ast.AssignStmt)
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if len(n.Lhs) != len(n.Rhs) {
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return
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}
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if len(n.Lhs) == 1 && n.Tok == token.DEFINE {
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return
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}
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for i, right := range n.Rhs {
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call, ok := right.(*ast.CallExpr)
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if !ok {
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continue
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}
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sel, ok := call.Fun.(*ast.SelectorExpr)
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if !ok {
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continue
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}
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pkgIdent, _ := sel.X.(*ast.Ident)
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pkgName, ok := pass.TypesInfo.Uses[pkgIdent].(*types.PkgName)
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if !ok || pkgName.Imported().Path() != "sync/atomic" {
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continue
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}
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switch sel.Sel.Name {
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case "AddInt32", "AddInt64", "AddUint32", "AddUint64", "AddUintptr":
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checkAtomicAddAssignment(pass, n.Lhs[i], call)
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}
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}
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})
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return nil, nil
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}
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// checkAtomicAddAssignment walks the atomic.Add* method calls checking
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// for assigning the return value to the same variable being used in the
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// operation
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func checkAtomicAddAssignment(pass *analysis.Pass, left ast.Expr, call *ast.CallExpr) {
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if len(call.Args) != 2 {
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return
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}
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arg := call.Args[0]
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broken := false
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gofmt := func(e ast.Expr) string { return analysisutil.Format(pass.Fset, e) }
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if uarg, ok := arg.(*ast.UnaryExpr); ok && uarg.Op == token.AND {
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broken = gofmt(left) == gofmt(uarg.X)
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} else if star, ok := left.(*ast.StarExpr); ok {
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broken = gofmt(star.X) == gofmt(arg)
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}
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if broken {
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pass.Reportf(left.Pos(), "direct assignment to atomic value")
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}
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}
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