| // +build ignore |
| |
| // 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. |
| |
| package main |
| |
| import ( |
| "go/ast" |
| "go/token" |
| "go/types" |
| ) |
| |
| func init() { |
| register("atomic", |
| "check for common mistaken usages of the sync/atomic package", |
| checkAtomicAssignment, |
| assignStmt) |
| } |
| |
| // checkAtomicAssignment walks the assignment statement checking for common |
| // mistaken usage of atomic package, such as: x = atomic.AddUint64(&x, 1) |
| func checkAtomicAssignment(f *File, node ast.Node) { |
| n := node.(*ast.AssignStmt) |
| if len(n.Lhs) != len(n.Rhs) { |
| return |
| } |
| if len(n.Lhs) == 1 && n.Tok == token.DEFINE { |
| return |
| } |
| |
| for i, right := range n.Rhs { |
| call, ok := right.(*ast.CallExpr) |
| if !ok { |
| continue |
| } |
| sel, ok := call.Fun.(*ast.SelectorExpr) |
| if !ok { |
| continue |
| } |
| pkgIdent, _ := sel.X.(*ast.Ident) |
| pkgName, ok := f.pkg.uses[pkgIdent].(*types.PkgName) |
| if !ok || pkgName.Imported().Path() != "sync/atomic" { |
| continue |
| } |
| |
| switch sel.Sel.Name { |
| case "AddInt32", "AddInt64", "AddUint32", "AddUint64", "AddUintptr": |
| f.checkAtomicAddAssignment(n.Lhs[i], call) |
| } |
| } |
| } |
| |
| // checkAtomicAddAssignment walks the atomic.Add* method calls checking for assigning the return value |
| // to the same variable being used in the operation |
| func (f *File) checkAtomicAddAssignment(left ast.Expr, call *ast.CallExpr) { |
| if len(call.Args) != 2 { |
| return |
| } |
| arg := call.Args[0] |
| broken := false |
| |
| if uarg, ok := arg.(*ast.UnaryExpr); ok && uarg.Op == token.AND { |
| broken = f.gofmt(left) == f.gofmt(uarg.X) |
| } else if star, ok := left.(*ast.StarExpr); ok { |
| broken = f.gofmt(star.X) == f.gofmt(arg) |
| } |
| |
| if broken { |
| f.Bad(left.Pos(), "direct assignment to atomic value") |
| } |
| } |