@webassemblyjs/helper-wasm-section

What is @webassemblyjs/helper-wasm-section?

The @webassemblyjs/helper-wasm-section package is part of the WebAssemblyJS project and provides utility functions for manipulating sections in WebAssembly (Wasm) binary files. It allows developers to parse, add, or modify sections within a Wasm binary, which can be useful for tasks such as Wasm optimization, analysis, or transformation.

What are @webassemblyjs/helper-wasm-section's main functionalities?

Parsing a Wasm section

This feature allows you to parse a specific section of a WebAssembly binary. The code sample demonstrates how to use the `getSectionMetadata` function to retrieve metadata for the 'type' section of a Wasm binary.

const { decode } = require('@webassemblyjs/wasm-parser');
const { getSectionMetadata } = require('@webassemblyjs/helper-wasm-section');

const wasmBuffer = ...; // A buffer containing the Wasm binary
const ast = decode(wasmBuffer);
const typeSectionMetadata = getSectionMetadata(ast, 'type');

Adding a new Wasm section

This feature allows you to add a new section to a WebAssembly binary. The code sample shows how to use the `addSection` function to add a new section to the AST of a Wasm binary and then encode it back into a binary format.

const { addSection } = require('@webassemblyjs/helper-wasm-section');
const { encode } = require('@webassemblyjs/wasm-gen');

const ast = ...; // The AST of a Wasm binary
const newSection = ...; // The new section to add
addSection(ast, newSection);
const newWasmBuffer = encode(ast);

Modifying an existing Wasm section

This feature allows you to modify the content of an existing section in a WebAssembly binary. The code sample illustrates how to use the `editSection` function to change the content of the 'code' section in the AST and then encode the modified AST back into a binary.

const { editSection } = require('@webassemblyjs/helper-wasm-section');
const { encode } = require('@webassemblyjs/wasm-gen');

const ast = ...; // The AST of a Wasm binary
const sectionName = 'code';
const newContent = ...; // The new content for the section
editSection(ast, sectionName, newContent);
const newWasmBuffer = encode(ast);

Other packages similar to @webassemblyjs/helper-wasm-section

wasm-edit

The wasm-edit package is also part of the WebAssemblyJS project and provides a higher-level API for manipulating Wasm binaries. It includes functionality to add, remove, and update sections, similar to @webassemblyjs/helper-wasm-section, but with a more abstracted interface.

wasm-parser

The wasm-parser package is another component of the WebAssemblyJS project that focuses on parsing Wasm binaries into an AST. While it does not directly manipulate sections, it is often used in conjunction with @webassemblyjs/helper-wasm-section to first parse a binary before modifying its sections.

wasm-opt

wasm-opt is a tool from the Binaryen project that optimizes Wasm binaries. It operates at a different level compared to @webassemblyjs/helper-wasm-section, providing optimizations and transformations on the binary rather than offering APIs for manual section manipulation.