The HipHop compiler for PHP

Abstract

Scripting languages are widely used to quickly accomplish a variety of tasks because of the high productivity they enable. Among other reasons, this increased productivity results from a combination of extensive libraries, fast development cycle, dynamic typing, and polymorphism. The dynamic features of scripting languages are traditionally associated with interpreters, which is the approach used to implement most scripting languages. Although easy to implement, interpreters are generally slow, which makes scripting languages prohibitive for implementing large, CPU-intensive applications. This efficiency problem is particularly important for PHP given that it is the most commonly used language for server-side web development.This paper presents the design, implementation, and an evaluation of the HipHop compiler for PHP. HipHop goes against the standard practice and implements a very dynamic language through static compilation. After describing the most challenging PHP features to support through static compilation, this paper presents HipHop's design and techniques that support almost all PHP features. We then present a thorough evaluation of HipHop running both standard benchmarks and the Facebook web site. Overall, our experiments demonstrate that HipHop is about 5.5× faster than standard, interpreted PHP engines. As a result, HipHop has reduced the number of servers needed to run Facebook and other web sites by a factor between 4 and 6, thus drastically cutting operating costs.

PHP2Uni: Building Unikernels Using Scripting Language Transpilation

“…The transpiler more directly relevant to this paper is HPHPc [8], a Facebook-developed transpiler from PHP to C++. Domain Specific Languages [22] are also well-known application domains for transpilers.…”

“…This is the approach adopted, for example, by rump-php. 1 In this paper we propose the use of transpilation techniques, made popular a few years ago by Facebook [8], to build unikernels from PHP code. Our approach-prototyped in PHP2Uni-is to transpile PHP code into C++ classes, and build unikernel images from them.…”

Static, lightweight includes resolution for PHP

“…Determining the actual file or files that can be included at runtime allows static analysis tools to get access to more of the program source that will be executed, opening up possibilities for more powerful analysis techniques to be applied [18] and enabling more powerful developer tools, including tools for finding errors, performing code refactoring, detecting security violations, and supporting standard IDE services such as "Jump to definition". Second, to ensure these algorithms works in practice, we have validated them empirically.…”

“…This may be just a difference of classification-we consider any include to be dynamic that has a non-literal operand, while Biggar also considers include expressions built using string literals, concatenation, and constants to be static (we do not for the reason mentioned above-constant definitions are not globally unique through the entire system). Zhao et al [18], the final version.…”

Object-sensitive Type Analysis of PHP

“…Request permissions from permissions@acm.org. [23], and has later led to the Hack language that seamlessly integrates with PHP and adds type annotations [22]. Moreover, type information can improve features like on-the-fly auto-completion, and type related error detection.…”