code review 6300062: cmd/cgo: make Go code order deterministic

cmd/cgo: make Go code order deterministic

The type declarations were being generated using
a range over a map, which meant that successive
runs produced different orders. This will make sure
successive runs produce the same files.

Fixes issue 3707.

[rsc, 2012-06-07 16:33:11]

Hello golang-dev@googlegroups.com,

I'd like you to review this change to
https://go.googlecode.com/hg/

[bradfitz, 2012-06-07 16:35:53]

LGTM

On Thu, Jun 7, 2012 at 9:33 AM, <rsc@golang.org> wrote:

> Reviewers: golang-dev_googlegroups.com,
>
> Message:
> Hello golang-dev@googlegroups.com,
>
> I'd like you to review this change to
> https://go.googlecode.com/hg/
>
>
> Description:
> cmd/cgo: make Go code order deterministic
>
> The type declarations were being generated using
> a range over a map, which meant that successive
> runs produced different orders. This will make sure
> successive runs produce the same files.
>
> Fixes issue 3707.
>
> Please review this at
http://codereview.appspot.com/**6300062/<http://codereview.appspot.com/6300062/>
>
> Affected files:
>  M src/cmd/cgo/main.go
>  M src/cmd/cgo/out.go
>
>
> Index: src/cmd/cgo/main.go
> ==============================**==============================**=======
> --- a/src/cmd/cgo/main.go
> +++ b/src/cmd/cgo/main.go
> @@ -22,6 +22,7 @@
>        "path/filepath"
>        "reflect"
>        "runtime"
> +       "sort"
>        "strings"
>  )
>
> @@ -33,9 +34,8 @@
>        GccOptions  []string
>        CgoFlags    map[string]string // #cgo flags (CFLAGS, LDFLAGS)
>        Written     map[string]bool
> -       Name        map[string]*Name    // accumulated Name from Files
> -       Typedef     map[string]ast.Expr // accumulated Typedef from Files
> -       ExpFunc     []*ExpFunc          // accumulated ExpFunc from Files
> +       Name        map[string]*Name // accumulated Name from Files
> +       ExpFunc     []*ExpFunc       // accumulated ExpFunc from Files
>        Decl        []ast.Decl
>        GoFiles     []string // list of Go files
>        GccFiles    []string // list of gcc output files
> @@ -51,7 +51,15 @@
>        Ref      []*Ref              // all references to C.xxx in AST
>        ExpFunc  []*ExpFunc          // exported functions for this file
>        Name     map[string]*Name    // map from Go name to Name
> -       Typedef  map[string]ast.Expr // translations of all necessary
> types from C
> +}
> +
> +func nameKeys(m map[string]*Name) []string {
> +       var ks []string
> +       for k := range m {
> +               ks = append(ks, k)
> +       }
> +       sort.Strings(ks)
> +       return ks
>  }
>
>  // A Ref refers to an expression of the form C.xxx in the AST.
> Index: src/cmd/cgo/out.go
> ==============================**==============================**=======
> --- a/src/cmd/cgo/out.go
> +++ b/src/cmd/cgo/out.go
> @@ -71,7 +71,8 @@
>        }
>
>        cVars := make(map[string]bool)
> -       for _, n := range p.Name {
> +       for _, key := range nameKeys(p.Name) {
> +               n := p.Name[key]
>                if n.Kind != "var" {
>                        continue
>                }
> @@ -94,14 +95,16 @@
>        }
>        fmt.Fprintf(fc, "\n")
>
> -       for _, n := range p.Name {
> +       for _, key := range nameKeys(p.Name) {
> +               n := p.Name[key]
>                if n.Const != "" {
>                        fmt.Fprintf(fgo2, "const _Cconst_%s = %s\n", n.Go,
> n.Const)
>                }
>        }
>        fmt.Fprintf(fgo2, "\n")
>
> -       for _, n := range p.Name {
> +       for _, key := range nameKeys(p.Name) {
> +               n := p.Name[key]
>                if n.FuncType != nil {
>                        p.writeDefsFunc(fc, fgo2, n)
>                }
> @@ -378,7 +381,8 @@
>        fmt.Fprintf(fgcc, "%s\n", f.Preamble)
>        fmt.Fprintf(fgcc, "%s\n", gccProlog)
>
> -       for _, n := range f.Name {
> +       for _, key := range nameKeys(f.Name) {
> +               n := f.Name[key]
>                if n.FuncType != nil {
>                        p.writeOutputFunc(fgcc, n)
>                }
>
>
>

[rsc, 2012-06-07 16:37:57]

*** Submitted as http://code.google.com/p/go/source/detail?r=319a9f3330d0 ***

cmd/cgo: make Go code order deterministic

The type declarations were being generated using
a range over a map, which meant that successive
runs produced different orders. This will make sure
successive runs produce the same files.

Fixes issue 3707.

R=golang-dev, bradfitz
CC=golang-dev
http://codereview.appspot.com/6300062