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How PVS-Studio does the bug search: methods and technologies

By Andrey Karpov | Jan 12, 2017 05:41 AM | Tags: static code analysis pvs-studio c++

PVS-Studio is a static code analyzer, that searches for errors and vulnerabilities in programs written in C, C++ and C#. In this article, I am going to uncover the technologies that we use in PVS-Studio analyzer. In addition to the general theoretical information, I will show practical examples of how certain technology allows the detection of bugs.

How PVS-Studio does the bug search: methods and technologies

by Andrey Karpov

From the article:

The definition of the pattern looks quite simple, but in practice the implementation of the diagnostic is quite complicated. It's not enough just to analyze only "#define RShift(a) a >> 3". If warnings are issued for all strings of this kind, there will be too many of them. We should have a look at the way the macro expands in every particular case, and try to define the situations where it was done intentionally, and when the brackets are really missing.

 

A “sorted view”--Nick Athanasiou

By Adrien Hamelin | Jan 11, 2017 12:59 PM | Tags: intermediate experimental

Sorting can be done many ways.

A “sorted view”

by Nick Athanasiou

From the article:

This installment elaborates on the creation of a “sorted_view” utility. The “References” section contains links to the complete code; throughout the article, we provide demos and snippets to showcase and explain the implementations. The section on modernizing the code contains real world applications of the following C++17 features:

  1. structured bindings
  2. template argument deduction for class templates

Order Your Members

By Jonas Devlieghere | Jan 11, 2017 04:17 AM | Tags: performance intermediate

How ordering members can impact performance.

Order Your Members

by Jonas Devlieghere

From the article:

The article highlights the impact that different choices regarding the ordering of members in a struct can have on the performance of your code. A lot can be achieved by taking into account some general guidelines.

(Not) detecting bugs--Andrzej Krzemieński

By Adrien Hamelin | Jan 10, 2017 02:24 PM | Tags: intermediate boost

Undefined behaviour can be dangerous.

(Not) detecting bugs

by Andrzej Krzemieński

From the article:

The following code contains a bug. A developer has spent quite some time looking for the source. The intent of this code is to iterate over two vectors simultaneously, from the first up to the one-before-last element. Thus the most interesting tools that will be employed will be boost::zip_iterator and std::prev.

#include <boost/iterator/zip_iterator.hpp>
#include <boost/tuple/tuple.hpp>
#include <vector>

using zip_iter = boost::zip_iterator<
                   boost::tuple<
                     std::vector<int>::iterator,
                     std::vector<int>::iterator
                   >
                 >;
int main()
{
  std::vector<int> v1 = {1, 2, 3, 4, 0};
  std::vector<int> v2 = {2, 3, 5, 7, 0};
    
  zip_iter beg {boost::make_tuple(v1.begin(), v2.begin())};
  zip_iter end {boost::make_tuple(v1.end(), v2.end())};
  
  auto process = [](zip_iter::reference){};
  std::for_each(beg, std::prev(end), process);
}

Add a const here, delete a const there…--Bruce Dawson

By Adrien Hamelin | Jan 10, 2017 02:19 PM | Tags: performance intermediate

Why constness is important in one article. Can be even better with constexpr.

Add a const here, delete a const there…

by Bruce Dawson

From the article:

I just completed a series of changes that shrunk the Chrome browser’s on-disk size on Windows by over a megabyte, moved about 500 KB of data from its read/write data segments to its read-only data segments, and reduced its private working set by about 200 KB per-process. The amusing thing about this series of changes is that they consisted entirely of removing const from some places, and adding const to others. Compilers be weird...