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| 1 // Copyright 2013 The Go Authors. All rights reserved. |
| 2 // Use of this source code is governed by a BSD-style |
| 3 // license that can be found in the LICENSE file. |
| 4 |
| 5 package main |
| 6 |
| 7 import ( |
| 8 "go/ast" |
| 9 "go/token" |
| 10 "sync/atomic" |
| 11 ) |
| 12 |
| 13 // checkAtomicAssignment walks the assignment statement checking for comomon |
| 14 // mistaken usage of atomic package, such as: x = atomic.AddUint64(&x, 1) |
| 15 func (f *File) checkAtomicAssignment(n *ast.AssignStmt) { |
| 16 if !*vetAtomic && !*vetAll { |
| 17 return |
| 18 } |
| 19 |
| 20 if len(n.Lhs) != len(n.Rhs) { |
| 21 return |
| 22 } |
| 23 |
| 24 for i, right := range n.Rhs { |
| 25 call, ok := right.(*ast.CallExpr) |
| 26 if !ok { |
| 27 continue |
| 28 } |
| 29 sel, ok := call.Fun.(*ast.SelectorExpr) |
| 30 if !ok { |
| 31 continue |
| 32 } |
| 33 pkg, ok := sel.X.(*ast.Ident) |
| 34 if !ok || pkg.Name != "atomic" { |
| 35 continue |
| 36 } |
| 37 |
| 38 switch sel.Sel.Name { |
| 39 case "AddInt32", "AddInt64", "AddUint32", "AddUint64", "AddUintp
tr": |
| 40 f.checkAtomicAddAssignment(n.Lhs[i], call) |
| 41 } |
| 42 } |
| 43 } |
| 44 |
| 45 // checkAtomicAddAssignment walks the atomic.Add* method calls checking for assi
gning the return value |
| 46 // to the same variable being used in the operation |
| 47 func (f *File) checkAtomicAddAssignment(left ast.Expr, call *ast.CallExpr) { |
| 48 arg := call.Args[0] |
| 49 broken := false |
| 50 |
| 51 if uarg, ok := arg.(*ast.UnaryExpr); ok && uarg.Op == token.AND { |
| 52 broken = f.gofmt(left) == f.gofmt(uarg.X) |
| 53 } else if star, ok := left.(*ast.StarExpr); ok { |
| 54 broken = f.gofmt(star.X) == f.gofmt(arg) |
| 55 } |
| 56 |
| 57 if broken { |
| 58 f.Warn(left.Pos(), "direct assignment to atomic value") |
| 59 } |
| 60 } |
| 61 |
| 62 type Counter uint64 |
| 63 |
| 64 func BadAtomicAssignmentUsedInTests() { |
| 65 x := uint64(1) |
| 66 x = atomic.AddUint64(&x, 1) // ERROR "direct assignment to atomic
value" |
| 67 _, x = 10, atomic.AddUint64(&x, 1) // ERROR "direct assignment to atomic
value" |
| 68 x, _ = atomic.AddUint64(&x, 1), 10 // ERROR "direct assignment to atomic
value" |
| 69 |
| 70 y := &x |
| 71 *y = atomic.AddUint64(y, 1) // ERROR "direct assignment to atomic value" |
| 72 |
| 73 var su struct{ Counter uint64 } |
| 74 su.Counter = atomic.AddUint64(&su.Counter, 1) // ERROR "direct assignmen
t to atomic value" |
| 75 z1 := atomic.AddUint64(&su.Counter, 1) |
| 76 _ = z1 // Avoid err "z declared and not used" |
| 77 |
| 78 var sp struct{ Counter *uint64 } |
| 79 *sp.Counter = atomic.AddUint64(sp.Counter, 1) // ERROR "direct assignmen
t to atomic value" |
| 80 z2 := atomic.AddUint64(sp.Counter, 1) |
| 81 _ = z2 // Avoid err "z declared and not used" |
| 82 |
| 83 au := []uint64{10, 20} |
| 84 au[0] = atomic.AddUint64(&au[0], 1) // ERROR "direct assignment to atomi
c value" |
| 85 au[1] = atomic.AddUint64(&au[0], 1) |
| 86 |
| 87 ap := []*uint64{&au[0], &au[1]} |
| 88 *ap[0] = atomic.AddUint64(ap[0], 1) // ERROR "direct assignment to atomi
c value" |
| 89 *ap[1] = atomic.AddUint64(ap[0], 1) |
| 90 } |
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