GDB Plug-In

Debugging LVGL with GDB

To facilitate debugging LVGL with GDB, a GDB plugin is provided. This plugin can be found in the lvgl/scripts/gdb directory. The GDB plugin can be used with any target where GDB is available. For example, you can use it to debug a device connected to a PC via JLink, which provides a GDB server. Additionally, if your device crashes and you have a core dump, you can use GDB to analyze the core dump. To load the LVGL GDB plugin within GDB's command line, type the following command:

source lvgl/scripts/gdb/gdbinit.py

Example of usage:

(gdb) source lvgl/scripts/gdb/gdbinit.py

(gdb) dump obj -L 2
obj@0x60700000dd10 (0,0,799,599)
tabview@0x608000204ca0 (0,0,799,599)
    obj@0x607000025da0 (0,0,799,69)
    obj@0x607000025e80 (0,70,799,599)
    obj@0x60700002bd70 (743,543,791,591)
    btn@0x60700002c7f0 (747,547,787,587)
keyboard@0x60d0000f7040 (0,300,799,599)
dropdown-list@0x608000205420 (0,0,129,129)
    label@0x60d0000f7ba0 (22,22,56,39)
(gdb)

The plugin provides the following commands.

• dump obj: Dump the object tree.

• info style: Show the object's style.

• info draw_unit: Display all current drawing unit information.

Note

Some versions of gdb on Windows (e.g. those delivered with various versions of Perl) are compiled without Python support, so the source command will not be supported.

Dump Obj Tree

dump obj: Dump the object tree.

dump obj -L 2: Dump the object tree with a depth of 2.

dump obj -a 0x60700000dd10: Dump the object tree starting from the specified address.

Show Obj's Style

This command can dump the object's local style, since style value is a union, it's displayed in all possible formats.

info style address_of_obj: Show the object's style.

Example:

(gdb) info style 0x60700000dd10
  32 = {num = 90, ptr = 0x5a, color = {blue = 90 'Z', green = 0 '\000', red = 0 '\000'}}
  158 = {num = 32767, ptr = 0x7fff, color = {blue = 255 '\377', green = 127 '\177', red = 0 '\000'}}
(gdb) p lv_global->disp_default->act_scr
$4 = (lv_obj_t *) 0x60700000dd10
(gdb) info style $4
  32 = {num = 90, ptr = 0x5a, color = {blue = 90 'Z', green = 0 '\000', red = 0 '\000'}}
  158 = {num = 32767, ptr = 0x7fff, color = {blue = 255 '\377', green = 127 '\177', red = 0 '\000'}}
(gdb)

Connecting to a Debugger

This command provides the ability to connect and debug GDB Python Script using IDE.

Connect to PyCharm / VSCode / Eclipse (not supported yet)

debugger -t pycharm

debugger -t vscode

debugger -t eclipse

Perform a web search for pydevd_pycharm or debugpy for details about how to use the debugger.