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Documentation/Debugging/WithVSCode.md

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+# Debugging with Visual Studio Code
+
+Visual Studio Code's built in debugging UI simplifies the debugging process for many who are not familiar with gdb or who prefer to work completely within their IDE.
+
+Here's what it looks like when it's all set up.
+
+![](vscode-debugger.png)
+
+
+## Steps
+
+1. [Build and launch the debug build of the browser](#Debug-Task)
+1. [Attach the VSCode debugger to one of the browser's child processes](#Attach-and-Debug)
+1. [Detach once finished debugging](#Detach)
+
+### Debug Task
+
+Update your `.vscode/tasks.json` config to include the following "launch debug" task. This will build Ladybird using the `BUILD_PRESET=Debug` option and launch the browser. Once the browser is running, you can then run the "Attach and debug" launch command described below.
+
+<details>
+<summary>.vscode/tasks.json</summary>
+
+```json
+{
+    "version": "2.0.0",
+    "tasks": [
+        {
+            "label": "launch debug",
+            "type": "shell",
+            "command": "bash",
+            "args": [
+                "-c",
+                // Update this to use your system's run command. 
+                // Default:
+                //   BUILD_PRESET=Debug Meta/ladybird.sh run ladybird
+                // MacOS with Homebrew clang:
+                //   CC=$(brew --prefix llvm)/bin/clang CXX=$(brew --prefix llvm)/bin/clang++ BUILD_PRESET=Debug Meta/ladybird.sh run ladybird
+                "CC=$(brew --prefix llvm)/bin/clang CXX=$(brew --prefix llvm)/bin/clang++ BUILD_PRESET=Debug Meta/ladybird.sh run ladybird"
+            ],
+            "options": {
+                "env": {
+                    // Put your custom run configuration here
+                }
+            },
+            "problemMatcher": [
+                {
+                    "base": "$gcc",
+                    "fileLocation": [
+                        "relative",
+                        "${workspaceFolder}/Build/ladybird-debug"
+                    ]
+                },
+                {
+                    "source": "gcc",
+                    "fileLocation": [
+                        "relative",
+                        "${workspaceFolder}/Build/ladybird-debug"
+                    ],
+                    "pattern": [
+                        {
+                            "regexp": "^([^\\s]*\\.S):(\\d*): (.*)$",
+                            "file": 1,
+                            "location": 2,
+                            "message": 3
+                        }
+                    ]
+                },
+                {
+                    "source": "Assertion Failed",
+                    "owner": "cpp",
+                    "pattern": [
+                        {
+                            "regexp": "ASSERTION FAILED: (.*)$",
+                            "message": 1
+                        },
+                        {
+                            "regexp": "^((?:.*)\\.(h|cpp|c|S)):(\\d*)$",
+                            "file": 1,
+                            "location": 3
+                        }
+                    ],
+                    "fileLocation": [
+                        "relative",
+                        "${workspaceFolder}/Build/ladybird-debug"
+                    ]
+                }
+            ]
+        }
+    ]
+}
+
+```
+</details>
+
+
+### Attach and Debug
+
+Once a debug build of the browser is running, you will want to attach the VSCode debugger to it. Use the following launch command.
+
+**Note:** Be sure to update the "program" field to point to the debug binary for your system.
+
+Once the command is run, a VSCode window will pop up showing the running processes to select from. Select a Ladybird process to begin debugging. Add breakpoints in order to suspend execution at the location you're interested in.
+
+![](vscode-select-process.png)
+
+<details>
+<summary>.vscode/launch.json</summary>
+
+```json
+{
+  "version": "2.0.0",
+  "configurations": [
+    {
+      "name": "Attach and debug",
+      "type": "cppdbg",
+      "request": "attach",
+      // Note: this is MacOS specific, update to point to your *debug* binary
+      "program": "${workspaceRoot}/Build/ladybird-debug/bin/Ladybird.app/Contents/MacOS/Ladybird",
+      // Note: this is potentially MacOS specific, update to either "gdb" or "lldb"
+      // more info: https://code.visualstudio.com/docs/cpp/launch-json-reference#_mimode
+      "MIMode": "lldb",
+    },
+  ]
+}
+
+```
+</details>
+
+### Detach
+
+After you're finished debugging, detach the VSCode debugger from the running process. Use the Disconnect button from the debugging commands UI.
+
+![](vscode-debugging-commands.png)
+
+## Troubleshooting
+
+### I can step through frames but I don't see local variables
+
+This is most likely due to not building using `BUILD_PRESET=Debug` when running `./Meta/ladybird.sh`.