LLExec Linux Plugins Debug

Prerequisites

This page will show you how to debug LLExec plugins for the Linux platform. You need:

• A developer Linux Machine, or a Virtual Machine, with the target toolchain already installed.
• A target board running Linux and LLExec, with or without realtime extensions.

We suggest to use a free IDE called CodeLite, to debug the plugin.

Setup CodeLite

We assume you are using Linux Machine based on Ubuntu or debian. Please installa CodeLite from this website:
https://downloads.codelite.org/

Setup your environment

You have to export some environment variables in a login script,
ie ~/.profile, this is an example, correct with your toolchain settings:

export MY_SDK_PATH="/opt/sysroots"
export PATH="$MY_SDK_PATH/x86_64-pokysdk-linux/usr/bin/arm-poky-linux-gnueabi:$PATH"
export CCPREFIX="arm-poky-linux-gnueabi-"
export CCDEFINES="ALPLC_P_ARM9 -DALPLC_C_GCCARM9"
export CCFLAGS="-march=armv7-a -mfloat-abi=hard -mfpu=neon -mtune=cortex-a7 --sysroot=/home/dvdk/toolchain_xeno_1.0/sysroots/cortexa7hf-vfp-neon-poky-linux-gnueabi -fno-delete-null-pointer-checks "
export GDB_FULL_PATH="$MY_SDK_PATH/x86_64-pokysdk-linux/usr/bin/arm-poky-linux-gnueabi/$CCPREFIX"gdb
export SYSROOT_FULL_PATH="$MY_SDK_PATH/cortexa7hf-vfp-neon-poky-linux-gnueabi"

Open Codelite.
Click on the menu "Settings" --> "GDB Settings..."
A window will appear.
In the field "Debugger path" insert the full path of your toolchain debugger, ie:

/opt/sysroots/x86_64-pokysdk-linux/usr/bin/arm-poky-linux-gnueabi/arm-poky-linux-gnueabi-gdb

Click on the menu "Settings" --> "Build Settings"
Click on button "Add compiler" then give it the name "CrossCompile gcc" Define the following fields:

C++ Compiler         = $(CCPREFIX)g++
C Compiler           = $(CCPREFIX)gcc
Assembler Name       = $(CCPREFIX)as
Linker               = $(CCPREFIX)g++
Shared Object Linker = $(CCPREFIX)g++ -shared -fPIC
Archive              = ar rcus
Resurce Compiler     = windres
Make                 = make -j 3

Compile Plugin Example

Click on the menu "Project" --> "Create Workspace", right click on the project node,
and then click on "Add an Existing Project".
Add the project "LLPlugin_EXAMPLE.project" under LLExec's plugin headers.
Click on the menu "Build" --> "Configuration manager" and select "LINUX_debug for the project.
Copy the file LLXPlugin_EXAMPLE.so, you can find under the directory TestProgram,
copy it in your target board, where LLExec is installed.
Then edit the file LLExecLinux.conf to add the reference to the new plugin:

<plugins>
  <plugin filename="./LLModbusTCP.so"/>
  <plugin filename="./LLModbusRTU.so"/>
  <plugin filename="./LLXPlugin_Database.so"/>
  <plugin filename="./LLXPlugin_ModbusSlave.so"/>
  <plugin filename="./LLXPlugin_FileSystem.so"/>
  <plugin filename="./LLXPlugin_Recipes.so"/>
  <plugin filename="./LLXPlugin_Alarms.so"/>
  <plugin filename="./LLXPlugin_EXEMPLE.so"/>
</plugins>

Debug plugin

The first thing to do, to debug the plugin, is to copy all so files and LLExec executable from the target directory /data/plc to the plugin headers directory on the developing machine, under directory ~/LLExec/TestProgram.

On the target kill all the LLExec instances:

~# killall -9 LLExec

From the /data/plc/ directory launch gdbserver:

/data/plc# gdbserver :8888 ./LLExec
 Process ./LLExec created; pid = 3864
 Listening on port 8888

On codelite right click on the LLXPlugin_EXAMPLE project and select Settings.
Un the new window, on the pane on the right select Debugger.
Check the option Debugging a remote target and insert IP address of the target and the port 8888.
On a terminal on the developer machine please check if is defined the environment variable SYSROOT_FULL_PATH:

echo $SYSROOT_FULL_PATH

If this variable is defined, open again the debugger settings for the project, switch to the TAB Startup commands and insert the command

set sysroot /apath/sysroots/cortexa7hf-vfp-neon-poky-linux-gnueabi

where the path is the content of your SYSROOT_FULL_PATH variable.


In the CodeLite IDE open the file LLXPlugin_EXAMPLE.cpp and set a breakpoint in the function

LLXPLG_INITIALIZEPLUGIN
{
   m_plcApi = *api; // <= press F9 to insert a breakpoint here
   return TRUE;
}

Now you can start debugging by pressing F5,
the program counter will stop on the breakpoint.

Stop debugger

In order to stop the debugger and restart a new debugging session you have to stop the debugger in the CodeLide IDE, by pressing shift F5
Please log in into the Target and give the command

killall -9 LLExec gdbserver