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// 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 atomic
import (
_ "embed"
"go/ast"
"go/token"
"golang.org/x/tools/go/analysis"
"golang.org/x/tools/go/analysis/passes/inspect"
"golang.org/x/tools/go/analysis/passes/internal/analysisutil"
"golang.org/x/tools/go/ast/inspector"
"golang.org/x/tools/go/types/typeutil"
)
//go:embed doc.go
var doc string
var Analyzer = &analysis.Analyzer{
Name: "atomic",
Doc: analysisutil.MustExtractDoc(doc, "atomic"),
URL: "https://pkg.go.dev/golang.org/x/tools/go/analysis/passes/atomic",
Requires: []*analysis.Analyzer{inspect.Analyzer},
RunDespiteErrors: true,
Run: run,
}
func run(pass *analysis.Pass) (interface{}, error) {
if !analysisutil.Imports(pass.Pkg, "sync/atomic") {
return nil, nil // doesn't directly import sync/atomic
}
inspect := pass.ResultOf[inspect.Analyzer].(*inspector.Inspector)
nodeFilter := []ast.Node{
(*ast.AssignStmt)(nil),
}
inspect.Preorder(nodeFilter, func(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
}
fn := typeutil.StaticCallee(pass.TypesInfo, call)
if analysisutil.IsFunctionNamed(fn, "sync/atomic", "AddInt32", "AddInt64", "AddUint32", "AddUint64", "AddUintptr") {
checkAtomicAddAssignment(pass, n.Lhs[i], call)
}
}
})
return nil, nil
}
// checkAtomicAddAssignment walks the atomic.Add* method calls checking
// for assigning the return value to the same variable being used in the
// operation
func checkAtomicAddAssignment(pass *analysis.Pass, left ast.Expr, call *ast.CallExpr) {
if len(call.Args) != 2 {
return
}
arg := call.Args[0]
broken := false
gofmt := func(e ast.Expr) string { return analysisutil.Format(pass.Fset, e) }
if uarg, ok := arg.(*ast.UnaryExpr); ok && uarg.Op == token.AND {
broken = gofmt(left) == gofmt(uarg.X)
} else if star, ok := left.(*ast.StarExpr); ok {
broken = gofmt(star.X) == gofmt(arg)
}
if broken {
pass.ReportRangef(left, "direct assignment to atomic value")
}
}
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