Devirtualization and Static Polymorphism | David Álvarez Rosa | Personal Website
Hacker News
February 25, 2026
AI-Generated Deep Dive Summary
Modern programming languages often rely on virtual dispatch to enable runtime polymorphism, but this approach can introduce significant overhead that impacts performance in latency-sensitive applications. The article by David Álvarez Rosa explores how virtual dispatch mechanisms, such as vtables and indirect calls, add pointer indirection, increase object sizes, and hinder inlining opportunities, leading to slower code execution. While compilers like GCC and Clang attempt to optimize through devirtualization—replacing runtime calls with compile-time resolved ones—it’s not always feasible without additional constraints or compiler flags. For developers aiming to maximize performance, manually replacing dynamic dispatch with static polymorphism can eliminate runtime overhead entirely.
The article delves into the technical details of virtual dispatch and devirtualization. Virtual methods in a base class generate vtables for each derived class, adding vptr pointers to objects. These vptrs enable dynamic method resolution but
Verticals
techstartups
Originally published on Hacker News on 2/25/2026