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mirror of https://github.com/golang/go synced 2024-11-18 14:34:39 -07:00
go/cmd/vet/atomic.go
David Symonds f895b43688 vet: Rearrange checkers to use a registration system.
This removes much of the AST logic out of main.go,
and makes it easier to build custom vet binaries

The trade-off in this change is for flexibility.
There's very little change in the per-check files,
a lot less code in main.go (specifically the AST walking
logic has shrunk), and it makes it much easier to build
custom vet binaries simply by dropping new source files
in the directory.

LGTM=josharian, r
R=r, josharian, kamil.kisiel
CC=golang-codereviews
https://golang.org/cl/83400043
2014-06-13 15:04:45 +10:00

67 lines
1.6 KiB
Go

// 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"
)
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
}
for i, right := range n.Rhs {
call, ok := right.(*ast.CallExpr)
if !ok {
continue
}
sel, ok := call.Fun.(*ast.SelectorExpr)
if !ok {
continue
}
pkg, ok := sel.X.(*ast.Ident)
if !ok || pkg.Name != "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")
}
}