code review 72360045: cmd/dist: set -Wuninitialized only when -O is also set.

cmd/dist: set -Wuninitialized only when -O is also set.
GCC on OS X 10.6 doesn't support -Wuninitialized without -O.
Fixes issue 7492.

[minux1, 2014-03-07 22:32:17]

Hello golang-codereviews@googlegroups.com,

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

[dave_cheney.net, 2014-03-07 22:37:06]

Wow. That must be an ancient version of Xcode. Your fix is correct, but I wonder
if it wouldn't be simpler to ask the OP to upgrade Xcode. I think Xcode 4 is
available for 10.6. 

> On 8 Mar 2014, at 9:32, minux.ma@gmail.com wrote:
> 
> Reviewers: golang-codereviews,
> 
> Message:
> Hello golang-codereviews@googlegroups.com,
> 
> I'd like you to review this change to
> https://code.google.com/p/go
> 
> 
> Description:
> cmd/dist: set -Wuninitialized only when -O is also set.
> GCC on OS X 10.6 doesn't support -Wuninitialized without -O.
> Fixes issue 7492.
> 
> Please review this at https://codereview.appspot.com/72360045/
> 
> Affected files (+7, -6 lines):
>  M src/cmd/dist/build.c
> 
> 
> Index: src/cmd/dist/build.c
> ===================================================================
> --- a/src/cmd/dist/build.c
> +++ b/src/cmd/dist/build.c
> @@ -457,7 +457,6 @@
>    "-Wstrict-prototypes",
>    "-Wextra",
>    "-Wunused",
> -    "-Wuninitialized",
>    "-Wno-sign-compare",
>    "-Wno-missing-braces",
>    "-Wno-parentheses",
> @@ -469,17 +468,19 @@
>    "-fno-common",
>    "-ggdb",
>    "-pipe",
> -#if defined(__NetBSD__) && defined(__arm__)
> -    // GCC 4.5.4 (NetBSD nb1 20120916) on ARM is known to mis-optimize
gc/mparith3.c
> -    // Fix available at http://patchwork.ozlabs.org/patch/64562/.
> -    "-O1",
> -#endif
> };
> 
> // gccargs2 is the second part of gccargs.
> // it is used if the environment isn't defining CFLAGS.
> static char *proto_gccargs2[] = {
> +    // on older versions of GCC, -Wuninitialized is not supported
> +    // without -O, so put it here together with -O settings in case
> +    // the user's $CFLAGS doesn't include -O.
> +    "-Wuninitialized",
> #if defined(__NetBSD__) && defined(__arm__)
> +    // GCC 4.5.4 (NetBSD nb1 20120916) on ARM is known to mis-optimize
gc/mparith3.c
> +    // Fix available at http://patchwork.ozlabs.org/patch/64562/.
> +    "-O1",
> #else
>    "-O2",
> #endif
> 
> 
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[minux1, 2014-03-07 22:57:10]

On Fri, Mar 7, 2014 at 5:36 PM, Dave Cheney <dave@cheney.net> wrote:

> Wow. That must be an ancient version of Xcode. Your fix is correct, but I
> wonder if it wouldn't be simpler to ask the OP to upgrade Xcode. I think
> Xcode 4 is available for 10.6.

I still need to move -O1 for NetBSD/ARM to the proto_gccargs2 array because
we don't need
force CFLAGS to -O1 on NetBSD/ARM.

[minux1, 2014-03-26 04:03:19]

ping

[minux1, 2014-03-26 04:03:33]

R=iant

[iant, 2014-03-26 05:47:12]

LGTM

[minux1, 2014-03-26 18:20:21]

*** Submitted as https://code.google.com/p/go/source/detail?r=7beaf39c4e79 ***

cmd/dist: set -Wuninitialized only when -O is also set.
GCC on OS X 10.6 doesn't support -Wuninitialized without -O.
Fixes issue 7492.

LGTM=iant
R=golang-codereviews, dave, iant
CC=golang-codereviews
https://codereview.appspot.com/72360045