Compilers

Pointer analysis is an important topic in compiler optimization. One interesting aspect is the dynamic scope of pointers. LLVM differentiates between two situations: Pointer Capture: A pointer value is captured if the function makes a copy of any part of the pointer that outlives the call. Pointer Escape: A pointer value escapes if it is accessible from outside the current function or thread. The latter case is sometimes considered separate and called thread-escape. Although the names seem to suggest that these two are opposites, it should be clear from their definition that they are not. Informally, escaping is concerned with the contents of the pointer, while capturing is concerned with the pointer itself[^1]. ...

The new C++17 standard brings many exciting new features. A smaller, more subtle improvement it brings is guaranteed copy elision. The keyword is guaranteed, as copy elision itself has always been part of the standard. Although it might not be a change as radical as, say, structured bindings, I’m very happy to see it made it into the standard. Copy Elision Before discussing what changed in the latest version of the standard, it might be useful to revisit the basics of copy elision as they are currently defined by the C++14 standard. If you already know what it is and how it works, feel free to skip this part. ...

Clang is everywhere; It is the core of my favorite Vim plugin YouCompleteMe, it recently got supported by Microsoft Visual Studio, it is mentioned in numerous episodes of CppCast and it powers the excellent clang formatter. Naturally, I wanted to get a better understanding of how the clang front end works under the hood. Clang Front End & AST Clang is a C language family front end for LLVM. In compiler design, a front end takes care of the analysis part, which means breaking up the source code into pieces according to a grammatical structure. The result is an intermediate representation which is transformed in a target program by the back end, called synthesis. Optionally, there is an intermediate step between the front- and back end for optimization. ...