The Eclipse IDE is a popular development environment and it fully supports development using Yocto Project. When you install and configure the Eclipse Yocto Project Plug-in into the Eclipse IDE, you maximize your Yocto Project design experience. Installing and configuring the Plug-in results in an environment that has extensions specifically designed to let you more easily develop software. These extensions allow for cross-compilation, deployment, and execution of your output into a QEMU emulation session. You can also perform cross-debugging and profiling. The environment also supports a suite of tools that allows you to perform remote profiling, tracing, collection of power data, collection of latency data, and collection of performance data. This section describes how to install and configure the Eclipse IDE Yocto Plug-in and how to use it to develop your Yocto Project.

To develop within the Eclipse IDE, you need to do the following: Install the optimal version of the Eclipse IDE. Configure the Eclipse IDE. Install the Eclipse Yocto Plug-in. Configure the Eclipse Yocto Plug-in.

It is recommended that you have the Indigo 3.7 version of the Eclipse IDE installed on your development system. If you don’t have this version, you can find it at . From that site, choose the Eclipse Classic version particular to your development host. This version contains the Eclipse Platform, the Java Development Tools (JDT), and the Plug-in Development Environment. Once you have downloaded the tarball, extract it into a clean directory. For example, the following command unpacks and installs the Eclipse IDE into a clean directory using the default name eclipse: $ tar -xzvf ~/Downloads/Eclipse-SDK-3.7-linux-gtk-x86_64.tar.gz One issue exists that you need to be aware of regarding the Java Virtual machine’s garbage collection (GC) process. The GC process does not clean up the permanent generation space (PermGen). This space stores metadata descriptions of classes. The default value is set too small and it could trigger an out-of-memory error such as the following: Java.lang.OutOfMemoryError: PermGen space This error causes the application to hang. To fix this issue, you can use the --vmargs option when you start Eclipse to increase the size of the permanent generation space: eclipse --vmargs --XX:PermSize=256M

Before installing and configuring the Eclipse Yocto Plug-in, you need to configure the Eclipse IDE. Follow these general steps to configure Eclipse: Start the Eclipse IDE. Select "Install New Software" from the "Help" pull-down menu. Select Indego - http://download.eclipse.org/releases/indego from the "Work with:" pull-down menu. Expand the box next to Programming Languages and select the Autotools Support for CDT (incubation) and C/C++ Development Tools boxes. Complete the installation and restart the Eclipse IDE. Select "Install New Software" from the "Help" pull-down menu. After the Eclipse IDE restarts, click the "Available Software Sites" link. Check the box next to http://download.eclipse.org/tm/updates/3.3 and click "OK". Select http://download.eclipse.org/tm/updates/3.3 from the "Work with:" pull-down menu. Check the box next to TM and RSE Main Features. Expand the box next to TM and RSE Optional Add-ons and select every item except RSE Unit Tests and RSE WinCE Services (incubation). Complete the installation and restart the Eclipse IDE. After the Eclipse IDE restarts, click the "Available Software Sites" link. Check the box next to http://download.eclipse.org/tools/cdt/releases/indego and click "OK". Select http://download.eclipse.org/tools/cdt/releases/indego from the "Work with:" pull-down menu. Check the box next to CDT Main Features. Expand the box next to CDT Optional Features and select C/C++ Remote Launch and Target Communication Framework (incubation). Complete the installation and restart the Eclipse IDE.

You can install the Eclipse Yocto Plug-in one of two methods: use Eclipse IDE commands, or use the build.sh script to build and then install a zip file of the plug-in.

To install the Eclipse Yocto Plug-in by using Eclipse IDE commands, follow these steps: Open a shell and create a Git repository with: $ git clone git://git.yoctoproject.org/yocto-eclipse yocto-eclipse For this example, I created ~/yocto-eclipse. In Eclipse, select "Import" from the "File" menu. Expand the "General" box and pick "existing projects into workspace". Select the root directory and browse to "~/yocto-eclipse/plugins". There will be three things there. Select each one and install one at a time. Do all three. Restart everything. At this point you should be able to invoke Eclipse from the shell using the following: $ cd ~/eclipse $ ./eclipse -vmargs -XX:PermSize=256M The left navigation pane shows the default projects. Right-click on one of these projects and run it as an Eclipse application. This brings up a second instance of Eclipse IDE that has the Yocto Plug-in.

To install the Eclipse Yocto Plug-in by building and installing a plug-in zip file, follow these steps: Open a shell and create a Git repository with: $ git clone git://git.yoctoproject.org/yocto-eclipse yocto-eclipse For this example, I created ~/yocto-eclipse. Locate the build.sh script in the Git repository you created in the previous step. The script is located in the scripts. Be sure to set the ECLIPSE_HOME environment variable to the top-level directory in which you installed the Indigo version of Eclipse. For example, if your Eclipse directory is $HOME/eclipse, use the following: ECLIPSE_HOME=$HOME/eclipse Run the build.sh script and provide the name of the Git branch along with the Yocto Project release you are using. Here is an example that uses the master Git repository and the 1.1M4 release: $ scripts/build.sh master 1.1M4 After running the script, the file org.yocto.sdk-<release>-<date>-archive.zip in the current directory. Install the zip file in the top-level directory of the installed Indigo Eclipse IDE. Restart the Eclipse IDE if necessary. At this point you should be able to invoke Eclipse from the shell using the following: $ cd ~/eclipse $ ./eclipse -vmargs -XX:PermSize=256M The left navigation pane shows the default projects. Right-click on one of these projects and run it as an Eclipse application. This brings up a second instance of Eclipse IDE that has the Yocto Plug-in.

Configuring the Eclipse Yocto Plug-in involves setting the Cross Compiler options and the Target options. The configurations you choose become the default settings for all projects. You do have opportunities to change them later when you configure the project (see the following section). To start, you need to do the following from within the Eclipse IDE: Choose Windows -> Preferences to display the Preferences Dialog Click Yocto ADT

To configure the Cross Compiler Options, you must select the type of toolchain, point to the toolchain, specify the sysroot location, and select the target architecture. Selecting the Toolchain Type: Choose between Standalone pre-built toolchain and Build system derived toolchain for Cross Compiler Options. Standalone Pre-built Toolchain: Select this mode when you are using a stand-alone cross-toolchain. For example, suppose you are an application developer and do not need to build a target image. Instead, you just want to use an architecture-specific toolchain on an existing kernel and target root filesystem. Build System Derived Toolchain: Select this mode if the cross-toolchain has been installed and built as part of the Yocto Project build tree. When you select Build system derived toolchain, you are using the toolchain bundled inside the Yocto Project build tree. Point to the Toolchain: If you are using a stand-alone pre-built toolchain, you should be pointing to the /opt/poky/$SDKVERSION directory. This is the location for toolchains installed by the ADT Installer or by hand. Sections "Configuring and Running the ADT Installer Script" and "Using a Cross-Toolchain Tarball" describe two ways to install a stand-alone cross-toolchain in the /opt/poky directory. It is possible to install a stand-alone cross-toolchain in a directory other than /opt/poky. However, doing so is discouraged. If you are using a system-derived toolchain, the path you provide for the Toolchain Root Location field is the Yocto Project's build directory. See section "Using BitBake and the Yocto Project Build Tree" for information on how to install the toolchain into the Yocto Project build tree. Specify the Sysroot Location: This location is where the root filesystem for the target hardware is created on the development system by the ADT Installer. The QEMU user-space tools, the NFS boot process, and the cross-toolchain all use the sysroot location. Select the Target Architecture: The target architecture is the type of hardware you are going to use or emulate. Use the pull-down Target Architecture menu to make your selection. The pull-down menu should have the supported architectures. If the architecture you need is not listed in the menu, you will need to build the image. See the "Building an Image" section of the The Yocto Project Quick Start for more information.

You can choose to emulate hardware using the QEMU emulator, or you can choose to run your image on actual hardware. QEMU: Select this option if you will be using the QEMU emulator. If you are using the emulator, you also need to locate the kernel and specify any custom options. If you selected Build system derived toolchain, the target kernel you built will be located in the Yocto Project build tree in tmp/deploy/images directory. If you selected Standalone pre-built toolchain, the pre-built image you downloaded is located in the directory you specified when you downloaded the image. Most custom options are for advanced QEMU users to further customize their QEMU instance. These options are specified between paired angled brackets. Some options must be specified outside the brackets. In particular, the options serial, nographic, and kvm must all be outside the brackets. Use the man qemu command to get help on all the options and their use. The following is an example: serial ‘<-m 256 -full-screen>’ Regardless of the mode, Sysroot is already defined as part of the Cross Compiler Options configuration in the Sysroot Location: field. External HW: Select this option if you will be using actual hardware. Click the OK button to save your plug-in configurations.

You can create two types of projects: Autotools-based, or Makefile-based. This section describes how to create Autotools-based projects from within the Eclipse IDE. For information on creating Makefile-based projects in a terminal window, see the section "Using the Command Line". To create a project based on a Yocto template and then display the source code, follow these steps: Select File -> New -> Project. Double click CC++. Double click C Project to create the project. Expand Yocto ADT Project. Select Hello World ANSI C Autotools Project. This is an Autotools-based project based on a Yocto Project template. Put a name in the Project name: field. Do not use hyphens as part of the name. Click Next. Add information in the Author and Copyright notice fields. Be sure the License field is correct. Click Finish. If the "open perspective" prompt appears, click "Yes" so that you in the C/C++ perspective. The left-hand navigation pane shows your project. You can display your source by double clicking the project's source file.

The earlier section, "Configuring the Eclipse Yocto Plug-in", sets up the default project configurations. You can override these settings for a given project by following these steps: Select Project -> Change Yocto Project Settings: This selection brings up the Project Yocto Settings Dialog and allows you to make changes specific to an individual project. By default, the Cross Compiler Options and Target Options for a project are inherited from settings you provide using the Preferences Dialog as described earlier in the "Configuring the Eclipse Yocto Plug-in" section. The Project Yocto Settings Dialog allows you to override those default settings for a given project. Make your configurations for the project and click "OK". Select Project -> Reconfigure Project: This selection reconfigures the project by running autogen.sh in the workspace for your project. The script also runs libtoolize, aclocal, autoconf, autoheader, automake --a, and ./configure.

To build the project, select Project -> Build Project. The console should update and you can note the cross-compiler you are using.

To start the QEMU emulator from within Eclipse, follow these steps: Expose the Run -> External Tools menu. Your image should appear as a selectable menu item. Select your image in the navigation pane to launch the emulator in a new window. If needed, enter your host root password in the shell window at the prompt. This sets up a Tap 0 connection needed for running in user-space NFS mode. Wait for QEMU to launch. Once QEMU launches, you can begin operating within that environment. For example, you could determine the IP Address for the user-space NFS by using the ifconfig command.

Once the QEMU emulator is running the image, you can deploy your application and use the emulator to perform debugging. Follow these steps to deploy the application. Select Run -> Debug Configurations... In the left area, expand C/C++Remote Application. Locate your project and select it to bring up a new tabbed view in the Debug Configurations Dialog. Enter the absolute path into which you want to deploy the application. Use the Remote Absolute File Path for C/C++Application: field. For example, enter /usr/bin/<programname>. Click on the Debugger tab to see the cross-tool debugger you are using. Click on the Main tab. Create a new connection to the QEMU instance by clicking on new. Select TCF, which means Target Communication Framework. Click Next. Clear out the host name field and enter the IP Address determined earlier. Click Finish to close the New Connections Dialog. Use the drop-down menu now in the Connection field and pick the IP Address you entered. Click Debug to bring up a login screen and login. Accept the debug perspective.

As mentioned earlier in the manual, several tools exist that enhance your development experience. These tools are aids in developing and debugging applications and images. You can run these user-space tools from within the Eclipse IDE through the Window -> YoctoTools menu. Once you pick a tool, you need to configure it for the remote target. Every tool needs to have the connection configured. You must select an existing TCF-based RSE connection to the remote target. If one does not exist, click New to create one. Here are some specifics about the remote tools: OProfile: Selecting this tool causes the oprofile-server on the remote target to launch on the local host machine. The oprofile-viewer must be installed on the local host machine and the oprofile-server must be installed on the remote target, respectively, in order to use. You must compile and install the oprofile-viewer from the source code on your local host machine. Furthermore, in order to convert the target's sample format data into a form that the host can use, you must have oprofile version 0.9.4 or greater installed on the host. You can locate both the viewer and server from . The oprofile-server is installed by default on the core-image-sato-sdk image. Lttng-ust: Selecting this tool runs usttrace on the remote target, transfers the output data back to the local host machine, and uses lttv-gui to graphically display the output. The lttv-gui must be installed on the local host machine to use this tool. For information on how to use lttng to trace an application, see . For Application, you must supply the absolute path name of the application to be traced by user mode lttng. For example, typing /path/to/foo triggers usttrace /path/to/foo on the remote target to trace the program /path/to/foo. Argument is passed to usttrace running on the remote target. PowerTOP: Selecting this tool runs powertop on the remote target machine and displays the results in a new view called powertop. Time to gather data(sec): is the time passed in seconds before data is gathered from the remote target for analysis. show pids in wakeups list: corresponds to the -p argument passed to powertop. LatencyTOP and Perf: latencytop identifies system latency, while perf monitors the system's performance counter registers. Selecting either of these tools causes an RSE terminal view to appear from which you can run the tools. Both tools refresh the entire screen to display results while they run.