code review 9377043: runtime: use enums instead static vars for debugging

runtime: use enums instead static vars for debugging
Compiler can detect and delete dead code with enums,
but can not with static vars.

[dvyukov, 2013-05-13 10:46:56]

Hello golang-dev@googlegroups.com,

I'd like you to review this change to
https://dvyukov%40google.com@code.google.com/p/go/

[dave_cheney.net, 2013-05-14 00:21:02]

I tried to land a patch like this a while back, hopefully you will have more
luck. 



On 13/05/2013, at 3:46, dvyukov@google.com wrote:

> Reviewers: golang-dev1,
> 
> Message:
> Hello golang-dev@googlegroups.com,
> 
> I'd like you to review this change to
> https://dvyukov%40google.com@code.google.com/p/go/
> 
> 
> Description:
> runtime: use enums instead static vars for debugging
> Compiler can detect and delete dead code with enums,
> but can not with static vars.
> 
> Please review this at https://codereview.appspot.com/9377043/
> 
> Affected files:
>  M src/pkg/runtime/chan.c
>  M src/pkg/runtime/slice.c
> 
> 
> Index: src/pkg/runtime/chan.c
> ===================================================================
> --- a/src/pkg/runtime/chan.c
> +++ b/src/pkg/runtime/chan.c
> @@ -11,7 +11,7 @@
> #define    MAXALIGN    7
> #define    NOSELGEN    1
> 
> -static    int32    debug    = 0;
> +enum { debug = 0 };
> 
> typedef    struct    WaitQ    WaitQ;
> typedef    struct    SudoG    SudoG;
> Index: src/pkg/runtime/slice.c
> ===================================================================
> --- a/src/pkg/runtime/slice.c
> +++ b/src/pkg/runtime/slice.c
> @@ -9,7 +9,7 @@
> #include "malloc.h"
> #include "race.h"
> 
> -static    bool    debug    = 0;
> +enum { debug = 0 };
> 
> static    void    makeslice1(SliceType*, intgo, intgo, Slice*);
> static    void    growslice1(SliceType*, Slice, intgo, Slice *);
> 
> 
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> 
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> 

[r, 2013-05-14 23:11:12]

LGTM

https://codereview.appspot.com/9377043/diff/3001/src/pkg/runtime/chan.c
File src/pkg/runtime/chan.c (right):

https://codereview.appspot.com/9377043/diff/3001/src/pkg/runtime/chan.c#newco...
src/pkg/runtime/chan.c:14: enum { debug = 0 };
multiple lines.

https://codereview.appspot.com/9377043/diff/3001/src/pkg/runtime/slice.c
File src/pkg/runtime/slice.c (right):

https://codereview.appspot.com/9377043/diff/3001/src/pkg/runtime/slice.c#newc...
src/pkg/runtime/slice.c:12: enum { debug = 0 };
multiple lines please to be consistent with the rest of the code.
enum {
   debug = 0
};

[dvyukov, 2013-05-15 07:09:57]

On 2013/05/14 23:11:12, r wrote:
> LGTM
> 
> https://codereview.appspot.com/9377043/diff/3001/src/pkg/runtime/chan.c
> File src/pkg/runtime/chan.c (right):
> 
>
https://codereview.appspot.com/9377043/diff/3001/src/pkg/runtime/chan.c#newco...
> src/pkg/runtime/chan.c:14: enum { debug = 0 };
> multiple lines.
> 
> https://codereview.appspot.com/9377043/diff/3001/src/pkg/runtime/slice.c
> File src/pkg/runtime/slice.c (right):
> 
>
https://codereview.appspot.com/9377043/diff/3001/src/pkg/runtime/slice.c#newc...
> src/pkg/runtime/slice.c:12: enum { debug = 0 };
> multiple lines please to be consistent with the rest of the code.
> enum {
>    debug = 0
> };

Done.
It needs to be:

enum
{
    debug = 0,
};

[dvyukov, 2013-05-15 07:10:32]

*** Submitted as https://code.google.com/p/go/source/detail?r=a23a2a12cd36 ***

runtime: use enums instead static vars for debugging
Compiler can detect and delete dead code with enums,
but can not with static vars.

R=golang-dev, dave, r
CC=golang-dev
https://codereview.appspot.com/9377043

[gobot, 2013-05-15 17:17:16]

R=r (assigned by r)