2008-01-29 23:17:51

by Timur Tabi

[permalink] [raw]
Subject: [PATCH] checkpatch: add __asm__ to function-space-paren exception list

checkpatch.pl thinks that __asm__ is a function name, so it complains about
a space between the function name and a parenthesis when it sees
"__asm__ ("mov ax,bx")".

This change will also encourage developers to use '__asm__' instead of 'asm'.

Signed-off-by: Timur Tabi <[email protected]>
---
scripts/checkpatch.pl | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 579f50f..971c822 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -1115,7 +1115,7 @@ sub process {

# check for spaces between functions and their parentheses.
while ($line =~ /($Ident)\s+\(/g) {
- if ($1 !~ /^(?:if|for|while|switch|return|volatile|__volatile__|__attribute__|format|__extension__|Copyright|case)$/ &&
+ if ($1 !~ /^(?:if|for|while|switch|return|volatile|__volatile__|__attribute__|format|__extension__|Copyright|case|__asm__)$/ &&
$line !~ /$Type\s+\(/ && $line !~ /^.\#\s*define\b/) {
WARN("no space between function name and open parenthesis '('\n" . $herecurr);
}
--
1.5.2.4


2008-02-04 11:21:42

by Andy Whitcroft

[permalink] [raw]
Subject: Re: [PATCH] checkpatch: add __asm__ to function-space-paren exception list

On Tue, Jan 29, 2008 at 05:17:28PM -0600, Timur Tabi wrote:
> checkpatch.pl thinks that __asm__ is a function name, so it complains about
> a space between the function name and a parenthesis when it sees
> "__asm__ ("mov ax,bx")".
>
> This change will also encourage developers to use '__asm__' instead of 'asm'.
>
> Signed-off-by: Timur Tabi <[email protected]>
> ---
> scripts/checkpatch.pl | 2 +-
> 1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> index 579f50f..971c822 100755
> --- a/scripts/checkpatch.pl
> +++ b/scripts/checkpatch.pl
> @@ -1115,7 +1115,7 @@ sub process {
>
> # check for spaces between functions and their parentheses.
> while ($line =~ /($Ident)\s+\(/g) {
> - if ($1 !~ /^(?:if|for|while|switch|return|volatile|__volatile__|__attribute__|format|__extension__|Copyright|case)$/ &&
> + if ($1 !~ /^(?:if|for|while|switch|return|volatile|__volatile__|__attribute__|format|__extension__|Copyright|case|__asm__)$/ &&
> $line !~ /$Type\s+\(/ && $line !~ /^.\#\s*define\b/) {
> WARN("no space between function name and open parenthesis '('\n" . $herecurr);
> }
> --

It truly is not clear what "type" of thing an __asm__ is these days.
Cirtainly it seems we can use it as an attribute of a type:

register unsigned long __r16 __asm__("$16") = rtc_access->function;

and yet also in its more traditional form:

__asm__(" call foo");

The latter form feels like a function? But cirtainly in the examples it
is shown with a space some of the time, and not others. Is __asm__ an
attribute of the null function (;) in this context or ... well ?

This patch really just removes any checks for spacing on __asm__ do we
have a preferred style for these? Attributes do seem to have spaces,
though in their most attribute like usage the __asm__ "attribute" does
not seem to be used with a space, so far anyhow.

Oh and why are we preferring the use of __asm__ over asm? They both
seem valid. Should we be recommending one over the other?

-apw

2008-02-04 16:39:16

by Timur Tabi

[permalink] [raw]
Subject: Re: [PATCH] checkpatch: add __asm__ to function-space-paren exception list

Andy Whitcroft wrote:

> It truly is not clear what "type" of thing an __asm__ is these days.
> Cirtainly it seems we can use it as an attribute of a type:
>
> register unsigned long __r16 __asm__("$16") = rtc_access->function;
>
> and yet also in its more traditional form:
>
> __asm__(" call foo");
>
> The latter form feels like a function?

But it's not. Sure, it defines a block of code that has input and output
parameters, but one key distinction is that __asm__ is not the name of the
"function".

? But cirtainly in the examples it
> is shown with a space some of the time, and not others.

Well, since checkpatch.pl insists that the space be removed, that's probably why
it's not there a lot of the time.

> Is __asm__ an
> attribute of the null function (;) in this context or ... well ?

I don't think __asm__ can be compared to other C-language syntax constructs.

> This patch really just removes any checks for spacing on __asm__ do we
> have a preferred style for these?

I don't know, but I do know it's wrong for checkpatch.pl to think that "__asm__"
is the name of a function.

> Attributes do seem to have spaces,
> though in their most attribute like usage the __asm__ "attribute" does
> not seem to be used with a space, so far anyhow.

The problem is that checkpatch.pl thinks this is okay:

__asm__ __volatile__ ("call foo");

but it doesn't like this:

__asm__ ("call foo");

> Oh and why are we preferring the use of __asm__ over asm? They both
> seem valid. Should we be recommending one over the other?

It's a toss-up. Depending on the architecture, one version has about 60% usage
and the other about 40%. I thought I read somewhere that __asm__ is preferred,
but I can't remember where I read that or who wrote it.

--
Timur Tabi
Linux kernel developer at Freescale