Liam Hurst

Liam Hurst

1597130579

Debugging WebAssembly with LLDB

WebAssembly has begun to establish itself outside of the browser via dedicated runtimes like Mozilla’s Wasmtime and Fastly’s Lucet. While the promise of a new, universal format for programs is appealing, it also comes with new challenges. For instance, how do you debug .wasm binaries?

At Mozilla, we’ve been prototyping ways to enable source-level debugging of .wasm files using traditional tools like GDB and LLDB.

The screencast below shows an example debugging session. Specifically, it demonstrates using Wasmtime and LLDB to inspect a program originally written in Rust, but compiled to WebAssembly.

This type of source-level debugging was previously impossible. And while the implementation details are subject to change, the developer experience—attaching a normal debugger to Wasmtime—will remain the same.

By allowing developers to examine programs in the same execution environment as a production WebAssembly program, Wasmtime’s debugging support makes it easier to catch and diagnose bugs that may not arise in a native build of the same code. For example, the WebAssembly System Interface (WASI) treats filesystem access more strictly than traditional Unix-style permissions. This could create issues that only manifest in WebAssembly runtimes.

Mozilla is proactively working to ensure that WebAssembly’s development tools are capable, complete, and ready to go as WebAssembly expands beyond the browser.

Please try it out and let us know what you think.

Note: Debugging using Wasmtime and LLDB should work out of the box on Linux with Rust programs, or with C/C++ projects built via the WASI SDK.

Debugging on macOS currently requires building and signing a more recent version of LLDB.

Unfortunately, LLDB for Windows does not yet support JIT debugging.

Thanks to Lin Clark, Till Schneidereit, and Yury Delendik for their assistance on this post, and for their work on WebAssembly debugging.

#webassembly #wasm #developer

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Buddha Community

Debugging WebAssembly with LLDB
Aileen  Jacobs

Aileen Jacobs

1596739200

What Is the Best Java Debugger?

Many people might think this a simple question; I am not one of them. I feel that in the modern world of development, there are too many factors to pick a single tool for debugging any language, let alone Java.

In The Beginning

Let’s take a step back and look at where we started with debugging, and while I am not going to get into the history of debugging, we should look at some of the basic tools used for debugging Java, aside from logging and system-out.

JDP

Let’s start with a quick look at the Java debugger (Java Discovery Protocol - JDP), which is a command-line tool used for debugging Java applications. This tool ships directly from Oracle, so you can be sure it will work; however, it can be complex to use and require knowledge of where you want to debug ahead of time.

A positive aspect of this tool is the fact that you can use it on the same box where the Java Virtual Machine (JVM) is running. This set-up means you do not need to deal with the complexities of connecting any external service that might be restricted by firewalls, which is particularly useful if you are deploying your Java applications into Docker containers. (which let’s be honest, who isn’t).

And while a command-line tool is not the best option for everyday work, what other options are available?

#java #performance #ide #debugging #debug #debuggers #debugging tools #debugging javascript

Justice  Reilly

Justice Reilly

1593517020

The Pain of Debugging WebAssembly

WASM can do some awesome things. But what’s not awesome? Debugging with WASM.

#development #devops #contributed #sponsored #debugging #webassembly

Debugging WebAssembly with Chrome Devtools

Get to know the tool stack for WebAssembly debugging.

WebAssembly is referred to as the modern binary format for the web. It is an open standard to develop applications running in the browser, allowing more than 40 programming languages, including C and C++, Python, Go, Java, Rust, and PHP.

“Most importantly, these programs can run near-native speeds in the browser.”

Debugging WebAssembly

Until recently, Chrome DevTools had limited support for WebAssemby debugging. We could only analyze individual instructions in a disassembled WebAssembly text formats and viewing raw stack traces.

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Screenshot by the Author

#programming #debugging #webassembly

Liam Hurst

Liam Hurst

1597130579

Debugging WebAssembly with LLDB

WebAssembly has begun to establish itself outside of the browser via dedicated runtimes like Mozilla’s Wasmtime and Fastly’s Lucet. While the promise of a new, universal format for programs is appealing, it also comes with new challenges. For instance, how do you debug .wasm binaries?

At Mozilla, we’ve been prototyping ways to enable source-level debugging of .wasm files using traditional tools like GDB and LLDB.

The screencast below shows an example debugging session. Specifically, it demonstrates using Wasmtime and LLDB to inspect a program originally written in Rust, but compiled to WebAssembly.

This type of source-level debugging was previously impossible. And while the implementation details are subject to change, the developer experience—attaching a normal debugger to Wasmtime—will remain the same.

By allowing developers to examine programs in the same execution environment as a production WebAssembly program, Wasmtime’s debugging support makes it easier to catch and diagnose bugs that may not arise in a native build of the same code. For example, the WebAssembly System Interface (WASI) treats filesystem access more strictly than traditional Unix-style permissions. This could create issues that only manifest in WebAssembly runtimes.

Mozilla is proactively working to ensure that WebAssembly’s development tools are capable, complete, and ready to go as WebAssembly expands beyond the browser.

Please try it out and let us know what you think.

Note: Debugging using Wasmtime and LLDB should work out of the box on Linux with Rust programs, or with C/C++ projects built via the WASI SDK.

Debugging on macOS currently requires building and signing a more recent version of LLDB.

Unfortunately, LLDB for Windows does not yet support JIT debugging.

Thanks to Lin Clark, Till Schneidereit, and Yury Delendik for their assistance on this post, and for their work on WebAssembly debugging.

#webassembly #wasm #developer

WebAssembly Tutorial: WebAssembly Debugging

WebAssembly Tutorial: WebAssembly Debugging

The current state of interactive debugging for WebAssembly and useful tips on how to do better.

Debugging WebAssembly, as with any code, is critical for both developers and implementers. In the case of WebAssembly, most developers I’ve met rely on println debugging because of a lack of documentation for alternatives. WebAssembly already supports step-through debugging of compiled code with integration and references to the original source, but using this tooling remains a hassle and lacks automation.

#WebAssembly #webdev