A few bugs have been lurking in the LLVM Bugzilla for a long time, namely #39427 and #35978, which are related to a custom implementation of the
is_trivially_copyable data type, and they have a bad impact on the Application Binary Interface (ABI) of LLVM libraries. In this article, I will take a closer look at these issues and describe potential workarounds.
The LLVM compiler infrastructure relies on several Advanced Data Types (ADT) to provide different speed/size trade-offs than the containers from the Standard Template Library (STL). Additionally, this ADT library provides features from future standard versions, but implemented in the C++ version (currently C++11) that LLVM supports as a code base. Finally, these ADTs must be compatible with the compiler requirements of the LLVM code base; basically, GCC version >= 4.8 and Clang version >= 3.1. (If you are interested in LLVM ADTs, Chandler Carruth did a nice talk on the subject at CppCon 2016.)
Continue reading “A look at LLVM Advanced Data Types and trivially copyable types”
“Fuzzing” an application is a great way to find bugs that may be missed by other testing methods. Fuzzers test programs by generating random string inputs and feeding them into an application. Any program that accepts arbitrary inputs from its users is a good candidate for fuzzing. This includes compilers, interpreters, web applications, JSON or YAML parsers, and many more types of programs.
libFuzzer is a library to assist with the fuzzing of applications and libraries. It is integrated into the Clang C compiler and can be enabled for your application with the addition of a compile flag and by adding a fuzzing target to your code. libFuzzer has been used successfully to find bugs in many programs, and in this article, I will show how you can integrate libFuzzer into your own applications.
Continue reading “Introduction to using libFuzzer with llvm-toolset”
On the heels of our recently announcement, General Availability of Clang/LLVM 6.0, Go 1.10, and Rust 1.29, I want to share how we’ll be supporting them going forward. Previously, these packages had been in “Technology Preview” status, which means that they were provided for “you to test functionality and provide feedback during the development process”, and were “not fully supported under Red Hat Subscription Level Agreements, may not be functionally complete, and are not intended for production use”.
So now that we’ve promoted them to fully supported status, what does that mean? In the simplest terms, General Availability (GA) means that these packages have officially entered the “Full Support Phase” of their lifecycle:
Continue reading “Support Lifecycle for Clang/LLVM, Go, and Rust”