static code analysis

PVS-Studio 7.11 Release: IAR Arm, Diagnostics, FREE-FREE-FREE-FREE

This is the press release of the New Year's version of the PVS-Studio 7.11 analyzer. Since the new version includes only a few enhancements, let's take this opportunity to recall the options for free PVS-Studio use.

PVS-Studio 7.11 Release: IAR Arm, Diagnostics, FREE-FREE-FREE-FREE

by Andrey Karpov

From the article:

Support of the IAR Arm compilers is now available in the pvs-studio-analyzer utility. This family of compilers was previously supported only in the CLMonitor.exe utility on Windows. Now users of PVS-Studio for Linux can check the code written for these compilers as well. We added interception of compiler calls via ld-linux to the pvs-studio-analyzer utility.

Why PVS-Studio Doesn't Offer Automatic Fixes

Static analyzer PVS-Studio can detect bugs in pretty complex and intricate parts of code, and coming up with appropriate fixes for such bugs may be a tough task even for human developers. That's exactly the reason why we should avoid offering any options for automatic fixing at all. Here are a couple of examples.

Why PVS-Studio Doesn't Offer Automatic Fixes

by Andrey Karpov

From the article:

But it only simplifies the code, not fixes it! Somebody else noticed this and opened a discussion: os_thread_windows.c - get_rel_wait() will block if abstime is in the past. As you can see, even humans make mistakes when trying to come up with a fix. Machines are just hopeless in that respect.

Checking Clang 11 with PVS-Studio

It's no secret that compilers employ their own built-in static code analyzers, and those are developing as well. That's why we write articles every now and then to show that our static analyzer, PVS-Studio, can find bugs even inside compilers and that we are worth our salt.

Checking Clang 11 with PVS-Studio

by Andrey Karpov

From the article:

The programmer is using a modulo operation to get a random value of either 0 or 1. But the value 1 seems to confuse developers and make them write the classic anti-pattern in which the modulo operation is performed on 1 instead of 2. The X % 1 operation is meaningless as it always evaluates to 0.

Part 2: Upsetting Opinions about Static Analyzers

By writing the article "Upsetting Opinions about Static Analyzers" we were supposed to get it off our chest and peacefully let it all go. However, the article unexpectedly triggered robust feedback. Unfortunately, the discussion went in the wrong direction, and now we will make a second attempt to explain our view of this situation.

Part 2: Upsetting Opinions about Static Analyzers

by Andrey karpov

From the article:

And started coming up with cases when it might be justified, which means that the PVS-Studio analyzer warning was a false-positive. Some speculations about the change in memory between two checks came into play which occurs due to:

  • running parallel threads;
  • signal/interrupt handlers;
  • the variable X is a reference to the element A[0];
  • hardware, such as performing DMA operations;
  • and so on.

After heated debate on the analyzer's inability to comprehend all cases, they left to cut down forest with axes. In other words, they found an excuse why they could still avoid using a static code analyzer in their work.

Upsetting Opinions about Static Analyzers

Static analysis tools have advanced far over the time they've been around. They no longer resemble the "linters" that were in active use 20 years ago. But some programmers still view them as extremely primitive tools. And that's very sad.

Upsetting Opinions about Static Analyzers

by Andrey Karpov

From the article:

Of course, any modern static analyzer tracks the changes of variables' values. If a variable doesn't change, a warning is issued. If it does, no warning is issued. To ensure that, analyzers rely on data stream analysis. And that's exactly how PVS-Studio works. Let's take a look at the following synthetic example.


 

Why it is important to apply static analysis for open libraries that you add to your project

If there are several options, it is useful to take time to analyze open libraries in order to choose the best one.

Why it is important to apply static analysis for open libraries that you add to your project

by Andrey Karpov

From the article:

Because of a typo, the original vector is returned, not the new scaledVector container. The same error occurs in the division operator. Facepalm. Again, these errors don't mean anything separately. Although, this is a hint that this library isn't used much and there is highly likely that there are other serious undetected errors in it.

PVS-Studio 7.09

Therefore, most likely, now each release will be followed by a special note so that users don't miss changes that may be useful to them. What's interesting is that from now on we won't just list everything that was added or improved. Rather, now on the contrary, the purpose is to highlight the most important features in the news to avoid having just a boring list of changes.

PVS-Studio 7.09

by Andrey Karpov

From the article:

New general analysis diagnostics:

  •     V1059. Macro name overrides a keyword/reserved name. This may lead to undefined behavior.
  •     V1060. Passing 'BSTR ' to the 'SysAllocString' function may lead to incorrect object creation.
  •     V1061. Extending 'std' or 'posix' namespace may result in undefined behavior.
  •     V1062. Class defines a custom new or delete operator. The opposite operator must also be defined.
  •     V1063. The modulo by 1 operation is meaningless. The result will always be zero.

PVS-Studio: analyzing pull requests in Azure DevOps using self-hosted agents

Static code analysis is most effective when changing a project, as errors are always more difficult to fix in the future than at an early stage. We continue expanding the options for using PVS-Studio in continuous development systems. This time, we'll show you how to configure pull request analysis using self-hosted agents in Microsoft Azure DevOps, using the example of the Minetest game.

PVS-Studio: analyzing pull requests in Azure DevOps using self-hosted agents

by Alexey Govorov

From the article:

The result is a build system based on MSBuild for C++, with Chocolatey for installing PVS-Studio, CMake, and Git. Vcpkg is built for convenient management of the libraries that the project depends on. Also, we have to download the latest version of the Azure Pipelines Agent. To initialize the agent from the ENTRYPOINT Docker file, the PowerShell script 'entrypoint.ps1' is called, to which you need to add the URL of the project's "organization", the token of the agent pool, and the PVS-Studio license parameters....


 

 

PVS-Studio is now in Compiler Explorer!

Now you can quickly and easily analyze the code for errors right on the godbolt.org site (Compiler Explorer). This feature opens up a large number of new possibilities – from quenching curiosity about the analyzer's abilities to being able to quickly share check results with a friend. Caution – GIFs!

PVS-Studio is now in Compiler Explorer

by George Gribkov

From the article:

If you want to see the output of your program, you can open the execution window by clicking "Add new... - > Execution only" in the code editor (not in the compiler window). In the gif below, you can see the output of the lab work taken from our page about free usage of PVS-Studio by students and teachers.

A Note of Caution about Using PVS-Studio on godbolt.org (Compiler Explorer)

We have added an option allowing you to experiment with the PVS-Studio static analyzer on the godbolt.org (Compiler Explorer) website. It supports analysis of C and C++ code.

A Note of Caution about Using PVS-Studio on godbolt.org (Compiler Explorer)

by Andrey Karpov

From the article:

This may be promising from the perspective of satisfying one's curiosity, writing articles, and so on. But there's a downside to it too: rather than using synthetic examples to explore or try out the tool, people may start relying on them to evaluate and compare it against other analyzers. And this is a very bad approach because the results will be unreliable and dependent on how the test examples are written.