How HHVM Uses Modern C++ for Fun and Profit (Literally)

by Drew Paroski

(watch on YouTube) (watch on Channel 9)

HHVM is a just-in-time compiler for PHP used by Facebook to serve billions of requests each day. This talk will give a quick overview of HHVM's history and architecture, followed by a deep dive into what made C++ the language of choice for writing HHVM.

C++ hits a sweet spot between performance and control on one end, and safety, maintainability, and convenience on the other.

The topics we’ll cover will include:
how to call into generated machine code from C++;
taking advantage of C++'s power to control "unsafe" details with memory including how memory is allocated, field size and layout, unions, reinterpret_casts, bit-stealing;
integrating generated machine code with C++ exception handling and C++ profiling tools;
leveraging templates and using the X Macro technique to improve performance and maintainability;
and taking advantage of new C++11 features like unrestricted unions and move constructors.
Finally, we'll go over some obstacles we encountered such as generating machine code that calls C++ virtual methods, and how C++'s superb flexibility allowed us to work around these obstacles.

Modernizing Legacy C++ Code

by James McNellis and Kate Gregory

(watch on YouTube) (watch on Channel 9)

C++ is a programming language with a long, storied history spanning over three decades--four if one includes its C ancestry. The C++ language has undergone many changes during that time, compiler technology has advanced substantially, and computers today are very different from the computers of decades past. But despite all of these advances, there's an awful lot of C++ code in use today that looks like it was written in the 1980s. In some cases, the code was written in the 1980s and it's still in use; in other cases, it's recently-written code that just doesn't use modern style.

In this talk, we'll discuss some of the problems with legacy code, and review some practical techniques for applying principles of modern C++ to gradually improve the quality of legacy code and improve maintainability and debuggability. We'll show how some very small changes to code can yield huge benefits.

Writing Data Parallel Algorithms on GPUs

by Ade Miller

(watch on YouTube) (watch on Channel 9)

Today most PCs, tablets and phones support multi-core processors and most programmers have some familiarity with writing (task) parallel code. Many of those same devices also have GPUs but writing code to run on a GPU is harder. Or is it?

Getting to grips with GPU programming is really about understanding things in a data parallel way. This talk will look at some of the common patterns for implementing algorithms on today's GPUs using examples from the C++ AMP Algorithms Library. Along the way it will cover some of the unique aspects of writing code for GPUs and contrast them with a more conventional code running on a CPU.

Designing value classes for modern C++

by Mark Mutz

C++11 is now widely available, and so is C++14. Like for users of the language, C++11/14 is a new language for C++ library writers, too. In this talk, we will walk you through the new C++ features that impact class design...

Sqlpp11, An EDSL For Type-Safe SQL In C++

by Roland Bock

Most C/C++ interfaces to SQL databases are string based. Theses strings effectively hide expression structures, names and types from the compiler. And they are vendor-specific. And they defer expression parsing and validation until the test phase or (even worse) production...

Back to the Basics! Essentials of Modern C++ Style

by Herb Sutter

(watch on YouTube) (watch on Channel 9)

This talk revisits basic questions, such as how to declare and initialize a variable, how to pass a value to a function, how to write a simple loop, and how to use smart pointers, in the light of experience with C++11 and the latest C++14 refinements. This involves examining auto, rvalue references, range-for loops, uniform initialization, lambda expressions, unique_ptr and shared_ptr, and more.

Objects? No Thanks!

by Wouter van Ooijen

Micro-controller programming can benefit from compile-time polymorphism without paying a run-time price by using static class templates...

Paying for Lunch: C++ in the ManyCore Age

moderated by Herb Sutter, with Pablo Halpern, Jared Hoberock, Artur Laksberg, Ade Miller, Gor Nishanov and Michael Wong.

(watch on YouTube) (watch on Channel 9)

Concurrency is one of the major focuses of C++17 and one of the biggest challenges facing C++ programmers today. Hear what this panel of experts has to say about how to write concurrent C++ now and in the future.

C++ on Mars: Incorporating C++ into Mars Rover Flight Software

by Mark Maimone

(watch on YouTube) (watch on Channel 9)

One of the more challenging aspects of developing flight software (FSW) for NASA's Spirit and Opportunity Mars Exploration Rovers (MER) and Curiosity, the Mars Science Laboratory rover was how to enable them to drive themselves safely through unknown Martian terrain. When the MER mission was approved in the year 2000, JPL researchers had already demonstrated that capability on prototype rovers [1] using software written primarily in C++ on a VxWorks realtime O/S platform with shared memory. So when asked to incorporate that capability into the MER vehicles which also relied on a similar VxWorks realtime O/S, the team concluded it would be safest and most expedient to incorporate the already field-tested C++ software. But that presented a challenge, since at that point all rover FSW development was mandated to be done mainly in the C programming language.

In this talk we present some of the challenges we faced and solutions we found in deploying C++ onto the Mars Rovers. For example, dynamic allocation was initially precluded, but development of a specialized memory allocator (using the C++ "placement new" operator) enabled us to incorporate it safely into the flight system. We will discuss what aspects of C++ were incorporated, what simulation environments aided development, describe some of the tools used to validate system behavior, and explain how our success using C++ for the implementation of autonomous navigation on MER has influenced future FSW efforts.

Interactive Metaprogramming Shell based on Clang

by Ábel Sinkovics

Developing metaprograms is hard and painful. Templight (http://plc.inf.elte.hu/templight/) supports the development and debugging of template metaprograms, but the code has to be recompiled after every minor change and tricks are needed to retrieve useful information about the result...