code review 13441051: build: more "undefined behavior" fixes

build: more "undefined behavior" fixes

Fixes issue 5764.

[rsc, 2013-09-10 18:42:09]

Hello golang-dev@googlegroups.com,

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

[bradfitz, 2013-09-10 18:47:21]

LGTM



On Tue, Sep 10, 2013 at 11:42 AM, <rsc@golang.org> wrote:

> Reviewers: golang-dev1,
>
> Message:
> Hello golang-dev@googlegroups.com,
>
> I'd like you to review this change to
> https://code.google.com/p/go/
>
>
> Description:
> build: more "undefined behavior" fixes
>
> Fixes issue 5764.
>
> Please review this at
https://codereview.appspot.**com/13441051/<https://codereview.appspot.com/134...
>
> Affected files (+5, -3 lines):
>   M src/cmd/6g/gsubr.c
>   M src/cmd/6l/obj.c
>   M src/cmd/6l/span.c
>   M src/libbio/bgetc.c
>
>
> Index: src/cmd/6g/gsubr.c
> ==============================**==============================**=======
> --- a/src/cmd/6g/gsubr.c
> +++ b/src/cmd/6g/gsubr.c
> @@ -540,7 +540,7 @@
>
>         nodconst(&n1, types[TINT64], c);
>
> -       if(as != AMOVQ && (c < -1LL<<31 || c >= 1LL<<31)) {
> +       if(as != AMOVQ && (c < -(1LL<<31) || c >= 1LL<<31)) {
>                 // cannot have 64-bit immediokate in ADD, etc.
>                 // instead, MOV into register first.
>                 regalloc(&ntmp, types[TINT64], N);
> Index: src/cmd/6l/obj.c
> ==============================**==============================**=======
> --- a/src/cmd/6l/obj.c
> +++ b/src/cmd/6l/obj.c
> @@ -346,7 +346,7 @@
>                 a->offset = BGETLE4(f);
>                 if(t & T_64) {
>                         a->offset &= 0xFFFFFFFFULL;
> -                       a->offset |= (vlong)BGETLE4(f) << 32;
> +                       a->offset |= (uvlong)BGETLE4(f) << 32;
>                 }
>         }
>         a->sym = S;
> Index: src/cmd/6l/span.c
> ==============================**==============================**=======
> --- a/src/cmd/6l/span.c
> +++ b/src/cmd/6l/span.c
> @@ -1237,6 +1237,8 @@
>                 break;
>         }
>
> +       if(z >= nelem(o->op))
> +               sysfatal("asmins bad table %P", p);
>         op = o->op[z];
>         if(op == 0x0f) {
>                 *andptr++ = op;
> Index: src/libbio/bgetc.c
> ==============================**==============================**=======
> --- a/src/libbio/bgetc.c
> +++ b/src/libbio/bgetc.c
> @@ -83,7 +83,7 @@
>
>         l = Bgetle2(bp);
>         h = Bgetle2(bp);
> -       return l|(h<<16);
> +       return l|((uint32)h<<16);
>  }
>
>  int
>
>
> --
>
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[rsc, 2013-09-10 18:54:59]

*** Submitted as https://code.google.com/p/go/source/detail?r=ecc9ab36456e ***

build: more "undefined behavior" fixes

Fixes issue 5764.

R=golang-dev, bradfitz
CC=golang-dev
https://codereview.appspot.com/13441051