Yocto Programming with VSCode: Difference between revisions
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|'''main.cpp''' || Source code for hello.bin | |'''main.cpp''' || Source code for hello.bin | ||
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|'''Makefile''' || | |'''Makefile''' || Makefile to cross compile '''main.cpp''' | ||
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|'''.vscode/tasks.json''' || VSCode file to override or add new tasks. Calls <code>make</code> when VSCode build command is executed. | |'''.vscode/tasks.json''' || VSCode file to override or add new tasks. Calls <code>make</code> when VSCode build command is executed. |
Revision as of 19:32, 26 July 2021
Visual Studio Code (VSCode) is a powerful, modern code editor that can be used to develop and debug C/C++ applications on Variscite System on Modules.
This guide demonstrates how to create and debug a C++ application using VSCode on the DART-MX8M-MINI.
Setup Host Computer Environment
Please follow the steps below to prepare a fresh Ubuntu 20.04 installation for VSCode debugging:
Install Dependencies
$ sudo apt-get -y update $ sudo apt-get -y install build-essential gdb gdb-multiarch git
Install VSCode
$ sudo snap install --classic code
Install VSCode Extensions
VSCode has a graphical interface for installing and managing extensions. To learn more, please see Using extensions in Visual Studio Code
For this guide, we will install the required extensions using the command line:
$ code --install-extension ms-vscode.cpptools
Install Yocto Toolchain
A toolchain is necessary for cross compiling applications. To install the toolchain, follow Variscite's Yocto Toolchain installation guide.
Create, cross compile, and run a new "Hello, World!" project
First, open a new terminal and configure the environment with the toolchain setup script:
$ source /opt/fslc-xwayland/3.1/environment-setup-aarch64-fslc-linux
From the same terminal, create an empty project directory and open VSCode:
$ mkdir ~/var-hello-world $ cd ~/var-hello-world $ code .
This will launch VSCode with ~/var-hello-world as working directory (which is currently empty):
Next, we will create the following files:
main.cpp | Source code for hello.bin |
Makefile | Makefile to cross compile main.cpp |
.vscode/tasks.json | VSCode file to override or add new tasks. Calls make when VSCode build command is executed.
|
To create a new file or folder, right click in the explorer view and select New File or New Folder:
Create a new file called main.cpp:
main.cpp:
#include <stdio.h> int main(int argc, char *argv[]) { printf("Hello, World!\n"); return 0; }
Create a new Makefile to build hello.bin:
Makefile:
all: main.cpp $(CXX) $(CXXFLAGS) -Og main.cpp -g -o hello.bin clean: rm -f hello.bin
Create a new folder named .vscode. Then, create a new file .vscode/tasks.json
.vscode/tasks.json:
{ "version": "2.0.0", "tasks": [{ "label": "build", "type": "shell", "command": "make clean; make -j$(nproc)", "problemMatcher": [], }] }
Your workspace should look similar to this:
Compile the project by selecting Terminal->Run Build Task... or entering Ctrl+Shift+B
:
Send hello.bin to the target device using SCP:
$ scp hello.bin root@<ip addr>:/home/root/
Launch hello.bin on the target device:
# ./hello.bin Hello, World!
Remote Debugging with VSCode
After verifying hello.bin runs on the target device, we can now setup VSCode for remote debugging.
The working directory should currently have these files:
~/var-hello-world$ find . ./Makefile ./main.cpp
We will add three files to the project:
var-build-and-debug.sh | Generic script to build, deploy, and launch gdbserver |
.vscode/launch.json | VSCode file to configure debug settings. Runs var-build-and-debug in tasks.json
|
.vscode/tasks.json | VSCode file to override or add new tasks. Calls var-debug-and-debug.sh prior to debugging.
|
Create var-build-and-debug.sh
First, add a generic script to build, deploy, and launch gdbserver. The script requires two arguments:
TARGET_IP
: The IP Address of the target devicePROGRAM
: The name of the binary executable,hello.bin
in this example
In the end, tasks.json will run this script at the beginning of each debug session.
var-build-and-debug.sh:
#!/bin/bash readonly TARGET_IP="$1" readonly PROGRAM="$2" readonly TARGET_DIR="/home/root" # rebuild project make clean; make -j$(nproc) # kill gdbserver on target ssh root@${TARGET_IP} "sh -c '/usr/bin/killall -q gdbserver; exit 0'" # send the program to the target scp ${PROGRAM} root@${TARGET_IP}:${TARGET_DIR} # start gdbserver on target REMOTE_GDB_CMD="ssh -t root@${TARGET_IP} \"sh -c 'cd ${TARGET_DIR}; gdbserver localhost:3000 ${PROGRAM}'\"" gnome-terminal -x bash -c "${REMOTE_GDB_CMD}"
Create launch.json
VSCode has a powerful built in debugger capable of debugging many programming languages. In this step, we will add a configuration for debugging CPP:
.vscode/launch.json:
{ "version": "0.2.0", "configurations": [{ "name": "GDB debug", "type": "cppdbg", "request": "launch", "program": "hello.bin", "args": [], "stopAtEntry": true, "cwd": "${workspaceFolder}", "environment": [], "console": "integratedTerminal", "MIMode": "gdb", "targetArchitecture": "arm64", "preLaunchTask": "var-build-and-debug", "setupCommands": [{ "description": "Enable pretty-printing for gdb", "text": "-enable-pretty-printing", "ignoreFailures": true }], "miDebuggerPath": "/usr/bin/gdb-multiarch", "miDebuggerServerAddress": "192.168.0.118:3000", }] }
See the table below for important details regarding launch.json variables:
miDebuggerServerAddress |
Must match the IP Address of the target device |
program |
Must match the name of the binary generated by the the Makefile |
preLaunchTask |
Must match the name of the task in .vscode/tasks.json in the following step
|
Create tasks.json
In launch.json
, we created a preLaunchTask
to run a task named var-build-and-debug
at the beginning of each debugging session. This task is configured by adding a .vscode/tasks.json file:
.vscode/tasks.json:
{ "version": "2.0.0", "tasks": [{ "label": "var-build-and-debug", "type": "shell", "command": "sh", "args": [ "var-build-and-debug.sh", "192.168.0.118", "hello.bin" ], } }
The following table summarizes variables in tasks.json:
label |
Must match preLaunchTask in launch.json |
type |
This task will launch a shell |
command |
Launch sh , with arguments var-build-and-debug.sh 192.168.0.136 hello.bin
|
Note: The IP Address must match the IP address of the target device, as defined in .vscode/launch.json
Launch a Debugging Session
After following the steps above, the working directory should now have these files:
~/var-hello-world$ find . ./.vscode ./.vscode/launch.json ./.vscode/tasks.json ./Makefile ./var-build-and-debug.sh ./main.cpp ./hello.bin
A new debugging session can be started by pressing 'F5' on the keyboard. Please click on the image below for a real time debugging demonstration:
Example Project Source Code
The source code for this example is available from Variscite's Github repository:
$ git clone https://github.com/nsdrude-varigit/var-demos $ cd var-demos/hello-world
Setup the toolchain environment:
$ source /opt/fslc-xwayland/3.1/environment-setup-aarch64-fslc-linux
Launch VSCode:
$ code .
Configure the target device IP Address in .vscode/tasks.json and .vscode/launch.json
Finally, start a debugging session by pressing 'F5' on the keyboard.