WebAssembly (WASM) for High Performance Apps · Aula

Depurando módulos WebAssembly

Utilize as ferramentas de desenvolvimento do navegador e outras técnicas de depuração para inspecionar e solucionar problemas em suas aplicações WASM.

Depurando módulos WebAssembly é uma aula grátis de WebAssembly (WASM) for High Performance Apps no CoddyKit. Esta é a aula 3 de 4. Você pode ler a aula completa abaixo gratuitamente — depois pratica ao vivo no navegador com um editor de código integrado e um tutor de IA 24/7. Faz parte do caminho de aprendizado de WebAssembly (WASM) for High Performance Apps, e seu progresso é sincronizado entre a web e o app CoddyKit. O curso de WebAssembly (WASM) for High Performance Apps inclui 4 aulas no total.

Partes desta aula ainda não foram traduzidas e aparecem em inglês.

Debugging WASM: An Overview

Ever wondered how to peek inside your WebAssembly code while it runs? Debugging WASM lets you find and fix issues in your high-performance modules.

It's a bit different from debugging pure JavaScript, but modern browser developer tools offer powerful capabilities to help you out.

Browser DevTools: Sources Tab

Your browser's developer tools are your best friend for WASM debugging. In Chrome, open DevTools (F12 or Cmd+Option+I).

Navigate to the Sources tab.
Look for your WASM module in the file tree, often under wasm:// or similar.
Without source maps, you'll see raw WebAssembly text format – which is very hard to read!

Source Maps: From WASM to Source

Debugging raw WebAssembly text is incredibly tough! Source maps are special files that link the compiled WASM code back to your original C, C++, or Rust source code.

When present, your browser can display your original source files, allowing you to debug them directly, just like JavaScript.

Rust & wasm-pack Source Maps

When compiling Rust to WASM, tools like wasm-pack can automatically generate source maps. The key is to compile in debug mode.

A simple Rust function that adds one to a number:

// src/lib.rs
#[no_mangle]
pub extern "C" fn add_one(num: i32) -> i32 {
    // This function adds 1 to the input number.
    // It will be exported from the WASM module.
    num + 1
}

Loading WASM & Source Maps

Let's see how a browser loads a WASM module. When compiled with source maps (e.g., wasm-pack build --target web --dev), the browser uses them to show your original Rust/C/C++ files in the Sources tab.

Here's how JavaScript loads a tiny, conceptual WASM module:

async function loadAndRunWasm() {
  // This is a conceptual WASM binary for 'add(a, b) => a + b'
  const wasmCode = new Uint8Array([
    0x00, 0x61, 0x73, 0x6d, 0x01, 0x00, 0x00, 0x00, 0x01, 0x07, 0x01, 0x60,
    0x02, 0x7f, 0x7f, 0x01, 0x7f, 0x03, 0x02, 0x01, 0x00, 0x07, 0x07, 0x01,
    0x03, 0x61, 0x64, 0x64, 0x00, 0x00, 0x0a, 0x09, 0x01, 0x07, 0x00, 0x20,
    0x00, 0x20, 0x01, 0x6a, 0x0b
  ]);

  const wasmModule = await WebAssembly.instantiate(wasmCode, {});
  const add = wasmModule.instance.exports.add;
  console.log("WASM add(5, 7):", add(5, 7)); // Expected: 12
}
loadAndRunWasm();

Pausing Execution with Breakpoints

Just like JavaScript, you can set breakpoints directly in your original C/C++/Rust source files shown in the Sources tab of your browser's DevTools.

Click on the line number in the gutter where you want to pause execution.
When your WASM code executes that line, the browser will pause, letting you inspect variables and the call stack.

Inspect Variables, Memory & Stack

When execution pauses at a breakpoint, you gain powerful insights:

Scope pane: View local variables and function arguments, often with their original names if source maps are good.
Memory Inspector: Use the dedicated 'Memory' tab or right-click a memory address to inspect WASM's linear memory buffer.
Call Stack pane: See the sequence of function calls that led to the current point, including both JavaScript and WASM frames.

Step-by-Step Execution

Once paused at a breakpoint, use the debugger controls to navigate your code line by line:

Step Over (F10): Execute the current line and move to the next.
Step Into (F11): Dive into a function call on the current line.
Step Out (Shift+F11): Finish executing the current function and return to where it was called.
Resume (F8): Continue execution until the next breakpoint or the program ends.

Debugging JS-WASM Interaction

Often, bugs occur at the boundary where JavaScript calls WASM functions or vice-versa. Set breakpoints in both your JavaScript and WASM code.

You can step seamlessly between JS and WASM execution frames in the DevTools call stack, making it easy to trace data flow and identify issues in the interop layer.

Debugging Knowledge Check

Test your understanding of WebAssembly debugging!

Debugging WASM: Recap

Today, you learned how to leverage browser developer tools to debug your WebAssembly applications. We covered:

Using source maps to see original source code.
Setting breakpoints and stepping through execution.
Inspecting variables, memory, and the call stack.
Debugging interactions between JavaScript and WASM.

Mastering these techniques is crucial for building robust and performant WASM applications. Keep practicing!

Perguntas Frequentes

A aula “Depurando módulos WebAssembly” é grátis?

Sim — o texto completo de “Depurando módulos WebAssembly” é grátis para ler aqui na web. Para praticá-la interativamente (um editor de código integrado e um tutor de IA 24/7) e desbloquear o restante do curso de WebAssembly (WASM) for High Performance Apps, atualize para CoddyKit PRO. O curso de WebAssembly (WASM) for High Performance Apps inclui 4 aulas no total.

O que vou aprender em “Depurando módulos WebAssembly”?

Utilize as ferramentas de desenvolvimento do navegador e outras técnicas de depuração para inspecionar e solucionar problemas em suas aplicações WASM. Você pratica WebAssembly (WASM) for High Performance Apps com código prático que executa diretamente no navegador, e um tutor de IA 24/7 responde suas dúvidas enquanto trabalha na aula.

Preciso ter experiência prévia para começar WebAssembly (WASM) for High Performance Apps?

Nenhuma experiência prévia é necessária. WebAssembly (WASM) for High Performance Apps no CoddyKit é estruturado para alunos iniciantes até avançados, então você pode começar aqui ou desde o início e aprender no seu ritmo. Esta é a aula 3 de 4.

Quanto tempo leva a aula “Depurando módulos WebAssembly”?

A maioria das aulas CoddyKit leva cerca de 5–10 minutos. Cada uma é compacta e interativa, então você faz progresso constante e retoma exatamente de onde parou entre web e app.

Posso escrever e executar código nesta aula de WebAssembly (WASM) for High Performance Apps?

Sim. Cada aula de WebAssembly (WASM) for High Performance Apps inclui um editor de código integrado, então você escreve e executa código real direto no navegador e recebe feedback de IA instantaneamente — nenhuma configuração local necessária.

Todas as aulas deste curso

← Voltar para WebAssembly (WASM) for High Performance Apps