The authoritative guide to the underlying development principles of PHP7: Understand the interpretation and compilation process of PHP

The authoritative guide to the underlying development principles of PHP7: Understand the interpretation and compilation process of PHP

With the rapid development of the Internet, Web development is widely used in various fields. As one of the most popular server-side scripting languages ​​in the world, PHP plays a pivotal role in web development. Although the PHP language itself is very simple and easy to learn, the underlying development principles of PHP are very complex. This article will give you an in-depth understanding of the underlying development principles of PHP7 and reveal the mystery of PHP interpretation and compilation.

The interpretation process of PHP refers to translating PHP script code into executable instructions so that the computer can understand and run it. During the interpretation process, the PHP interpreter first performs lexical analysis and syntax analysis on the script, converting the code into an abstract syntax tree (AST). Next, the interpreter converts the abstract syntax tree into intermediate code (opcode), and then executes the intermediate code line by line through interpretation and execution.

PHP’s compilation process is more complicated than the interpretation process. Compilation is the process of converting PHP script code into machine code so that the code can be executed on the CPU's instruction set. The compilation process generally includes steps such as lexical analysis, syntax analysis, semantic analysis, optimization and code generation.

Lexical analysis is to decompose the source code into lexical units, such as variable names, keywords, operators, etc. Grammatical analysis combines lexical units into structured sentences based on grammatical rules. Semantic analysis further analyzes the meaning of the code, checks whether the statement conforms to semantic rules, and generates intermediate representations, such as abstract syntax trees. Optimization is to optimize the performance of the code, such as eliminating redundant code, reducing jumps, etc., to improve the execution efficiency of the program. Finally, code generation converts the optimized code into machine code.

PHP7 introduces the new Zend Engine 3, which comprehensively optimizes and improves the underlying interpretation and compilation process. The new Zend Engine uses more efficient internal data structures and algorithms, and applies JIT (Just-In-Time) compilation technology. JIT compilation technology can dynamically compile hot code into machine code, thereby avoiding the performance loss caused by interpretation and execution, and greatly improving the execution speed of PHP.

In addition to the process of interpretation and compilation, the underlying development of PHP also involves memory management, exception handling, multi-threading, expansion mechanisms, etc. PHP's memory management uses a reference counting garbage collection mechanism. When the reference count decreases to zero, the memory is released. If a circular reference occurs, PHP will use the reachability analysis algorithm for garbage collection. Exception handling can capture and handle errors and exceptions during program running, improving the robustness and maintainability of the code. PHP's multi-threading support is implemented through the multi-process model, and a lock mechanism is used to solve thread safety issues. PHP also provides a rich extension mechanism, which can enhance the functionality of PHP by writing extensions.

Understanding the interpretation and compilation process of PHP7 is very important for a deep understanding of PHP's underlying principles and performance optimization. While mastering the underlying development principles of PHP, we can use the PHP language more flexibly for program development, and improve the execution efficiency and stability of the program by optimizing the code and expansion mechanism.

To sum up, the underlying development principles of PHP7 are a fairly large knowledge system, including the interpretation process and compilation process. In addition to understanding the underlying principles, we also need to be familiar with PHP's memory management, exception handling, multi-threading and expansion mechanisms, etc.

Through in-depth study and practice, we can better understand the underlying development principles of PHP, master the performance optimization skills of PHP7, and improve our Web development capabilities. I hope this article will help everyone understand the underlying development principles of PHP.

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