From: Julia Lawall <julia.lawall@inria.fr>
To: Derek M Jones <derek@knosof.co.uk>
Cc: cocci@inria.fr
Subject: Re: [cocci] ChatGPT 4 and Coccinelle
Date: Wed, 15 May 2024 08:00:04 +0200 (CEST) [thread overview]
Message-ID: <alpine.DEB.2.22.394.2405150758100.3404@hadrien> (raw)
In-Reply-To: <233b3043-2539-42f4-b47a-771b0094b558@knosof.co.uk>
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On Wed, 15 May 2024, Derek M Jones wrote:
> Julia,
>
> Our LLM overlords can create Coccinelle scripts.
> We are doomed!
I agree. The whole premise behind Coccinelle is that the intelligence and
responsability of the human behind the semantic patch will make up for the
added ability to introduce bad code on a large scale.
Nice touch with the "identifier var;" declaration...
julia
>
>
> Derek
> write a coccinelle pattern to match an if statement containing a single
> variable
>
> ChatGPT 4
>
> To create a Coccinelle semantic patch (spatch) to match an if statement in C
> code that contains a single variable, you can write a pattern that
> specifically looks for if statements and then checks if the condition inside
> the if statement consists solely of a single variable. Here’s a basic example
> of how you can define such a pattern using Coccinelle's transformation
> language:
>
> coccinelle
>
> @@
> identifier var;
> @@
>
> if (var)
> ...
>
> Here's a brief explanation of each part of this semantic patch:
>
> 1. @@: This symbol marks the start of a rule definition in Coccinelle.
> Everything between two @@ symbols constitutes one rule.
>
> 2. identifier var;: This line declares a metavariable named var that stands
> for any identifier in the code. In Coccinelle, metavariables allow you to
> abstract parts of the code so that your rules can match more generally without
> hardcoding specific variable names.
>
> 3. if (var): This line specifies the pattern to match—an if statement where
> the condition is exactly the identifier captured by var.
>
> 4. ...: The ellipsis (...) in Coccinelle matches any code. In this context,
> it means that anything can follow the if statement, without specifying what
> must be inside the if block.
>
> This simple semantic patch will match any if statement where the condition
> consists of a single variable, regardless of what that variable is or what
> code follows within the if block.
> To Apply This Patch:
>
> You would need to save the above code to a file with a .cocci extension, for
> example, single_var_if.cocci. Then you would run the Coccinelle tool on your
> source code directory like this:
>
> bash
>
> spatch --sp-file single_var_if.cocci --dir your_source_code_directory
>
> This command will apply the single_var_if.cocci semantic patch to all the C
> files in your_source_code_directory, showing where if statements with a single
> variable condition occur.
>
> For further customization or to make more complex patterns, you can refer to
> the Coccinelle documentation or look into more examples of Coccinelle semantic
> patches which can be found in various open-source projects and documentation
> resources.
>
> --
> Derek M. Jones Evidence-based software engineering
> blog:https://shape-of-code.com
>
next prev parent reply other threads:[~2024-05-15 6:00 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-15 0:44 [cocci] ChatGPT 4 and Coccinelle Derek M Jones
2024-05-15 6:00 ` Julia Lawall [this message]
2024-05-15 9:08 ` Derek M Jones
2024-05-15 9:13 ` Julia Lawall
2024-05-15 7:30 ` Markus Elfring
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