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Viewing changes to src/cmd/vet/atomic.go

  • Committer: Package Import Robot
  • Author(s): James Page
  • Date: 2013-08-20 14:06:23 UTC
  • mfrom: (14.1.23 saucy-proposed)
  • Revision ID: package-import@ubuntu.com-20130820140623-b414jfxi3m0qkmrq
Tags: 2:1.1.2-2ubuntu1
https://launchpad.net/bugs/1211749
https://launchpad.net/bugs/1202027
* Merge from Debian unstable (LP: #1211749, #1202027). Remaining changes:
  - 016-armhf-elf-header.patch: Use correct ELF header for armhf binaries.
  - d/control,control.cross: Update Breaks/Replaces for Ubuntu
    versions to ensure smooth upgrades, regenerate control file.

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src/cmd/vet/atomic.go
 
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// 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 main
 
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import (
 
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        "go/ast"
 
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        "go/token"
 
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)
 
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// checkAtomicAssignment walks the assignment statement checking for common
 
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// mistaken usage of atomic package, such as: x = atomic.AddUint64(&x, 1)
 
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func (f *File) checkAtomicAssignment(n *ast.AssignStmt) {
 
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        if !vet("atomic") {
 
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                return
 
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        }
 
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        if len(n.Lhs) != len(n.Rhs) {
 
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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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                pkg, ok := sel.X.(*ast.Ident)
 
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                if !ok || pkg.Name != "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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                        f.checkAtomicAddAssignment(n.Lhs[i], call)
 
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                }
 
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        }
 
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}
 
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// checkAtomicAddAssignment walks the atomic.Add* method calls checking for assigning the return value
 
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// to the same variable being used in the operation
 
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func (f *File) checkAtomicAddAssignment(left ast.Expr, call *ast.CallExpr) {
 
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        arg := call.Args[0]
 
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        broken := false
 
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        if uarg, ok := arg.(*ast.UnaryExpr); ok && uarg.Op == token.AND {
 
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                broken = f.gofmt(left) == f.gofmt(uarg.X)
 
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        } else if star, ok := left.(*ast.StarExpr); ok {
 
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                broken = f.gofmt(star.X) == f.gofmt(arg)
 
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        }
 
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        if broken {
 
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                f.Warn(left.Pos(), "direct assignment to atomic value")
 
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        }
 
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}