* [Cocci] qualified function rule
@ 2021-01-27 20:23 James K. Lowden
2021-01-27 20:35 ` Julia Lawall
2021-01-30 3:53 ` Mansour Moufid
0 siblings, 2 replies; 3+ messages in thread
From: James K. Lowden @ 2021-01-27 20:23 UTC (permalink / raw)
To: cocci
I don't understand how, if it's possible, to qualify a function in a
rule. I want the class of all functions having a parameter of a
particular type.
The code I'm working with has hundreds of unnecessary casts. Many
functions take a void* parameter, but are nonetheless called by casting
the parameter. For example, the parameters to memcpy(3) often
have casts applied.
I imagine writing a rule like
@@
type T, D;
identifier F(void*);
identifier D * data;
@@
- F((T*)data)
+ F(data)
but that doesn't work, and I haven't found anything that does.
In the kmalloc examples, I see things like
- \(kmalloc|kcmalloc\)(...)
+ mumble something
but that forces me to enumerate all such function names. It seems
vaguely like positions would do the trick, but, well, vaguely.
Is there a way?
--jkl
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^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [Cocci] qualified function rule
2021-01-27 20:23 [Cocci] qualified function rule James K. Lowden
@ 2021-01-27 20:35 ` Julia Lawall
2021-01-30 3:53 ` Mansour Moufid
1 sibling, 0 replies; 3+ messages in thread
From: Julia Lawall @ 2021-01-27 20:35 UTC (permalink / raw)
To: James K. Lowden; +Cc: cocci
On Wed, 27 Jan 2021, James K. Lowden wrote:
> I don't understand how, if it's possible, to qualify a function in a
> rule. I want the class of all functions having a parameter of a
> particular type.
>
> The code I'm working with has hundreds of unnecessary casts. Many
> functions take a void* parameter, but are nonetheless called by casting
> the parameter. For example, the parameters to memcpy(3) often
> have casts applied.
>
> I imagine writing a rule like
>
> @@
> type T, D;
> identifier F(void*);
> identifier D * data;
> @@
>
> - F((T*)data)
> + F(data)
>
> but that doesn't work, and I haven't found anything that does.
>
> In the kmalloc examples, I see things like
>
> - \(kmalloc|kcmalloc\)(...)
> + mumble something
>
> but that forces me to enumerate all such function names. It seems
> vaguely like positions would do the trick, but, well, vaguely.
>
> Is there a way?
In principle, you should be able to specify the type of F. But I'm not at
all sure that that is supported for function names.
Maybe it would suffice to do:
@fn@
identifier F,i;
parameter list[n] ps;
@@
F(ps,void *i,...) { ... }
@@
identifier fn.F;
expression list[fn.n] es;
type T;
expression *e;
@@
F(es,
- (T*)
e, ...)
@ty@
identifier F,i;
parameter list[n] ps;
type t;
@@
t F(ps,void *i,...);
@@
identifier ty.F;
expression list[ty.n] es;
type T;
expression *e;
@@
F(es,
- (T*)
e, ...)
Probably your function prototypes are not in the .c files, but rather in
things that they include. So you would want to use an argument like
--all-includes (include locally mentioned header) or --recursive-includes
(include headers included in other headers). You may want to give some -I
dir arguments to help it find the header files.
julia
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^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [Cocci] qualified function rule
2021-01-27 20:23 [Cocci] qualified function rule James K. Lowden
2021-01-27 20:35 ` Julia Lawall
@ 2021-01-30 3:53 ` Mansour Moufid
1 sibling, 0 replies; 3+ messages in thread
From: Mansour Moufid @ 2021-01-30 3:53 UTC (permalink / raw)
To: cocci
On Wed, Jan 27, 2021 at 3:23 PM James K. Lowden
<jklowden@schemamania.org> wrote:
>
> I don't understand how, if it's possible, to qualify a function in a
> rule. I want the class of all functions having a parameter of a
> particular type.
>
> The code I'm working with has hundreds of unnecessary casts. Many
> functions take a void* parameter, but are nonetheless called by casting
> the parameter. For example, the parameters to memcpy(3) often
> have casts applied.
>
> I imagine writing a rule like
>
> @@
> type T, D;
> identifier F(void*);
> identifier D * data;
> @@
>
> - F((T*)data)
> + F(data)
>
> but that doesn't work, and I haven't found anything that does.
Try:
@@
void *x;
@@
- (void *)(x)
+ x
or, to catch them all,
@@
type t;
t *x;
@@
- (t *)(x)
+ x
but this only works on function arguments when Coccinelle knows about
the function prototype from a header file (see the options
--include-headers and -I).
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