overlay_demo

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This project provides demonstration of using overlays. As the example used embedded RISC-V.

Project contains simple target overlay-manager ovlymgr.cpp (similar to the example from /gdb/testsuite/gdb.base).
GDB supports overlay debugging (GDB-doc: 14. Debugging Programs That Use Overlays). In addition, this project contains custom instruments (GDB-commands implemented with Python-GDB-API) for working with overlays.
These ideas can be used in full-size project that uses overlays. Details in the Wiki.

Custom GDB-commands for working with overlays

• 'ovreplace ovlymgr_name' - class ReplaceOverlayManager(gdb.Command): Replace target overlay-manager mode.
• 'ovload ovlyno' - class OverlayLoadManually(gdb.Command): Load specified overlay manually.
• 'getmapped' - class GetNumMappedOverlay(gdb.Command): Print numbers of mapped overlays.

Quick start

Get project:

    $ git clone ...
    $ cd overlay_demo
    $ git submodule update --init --recursive

Set actual paths in file '/overlay_demo/paths'.

Build project:

    make

There are two launch configurations for demonstration (setting in file '/overlay_demo/paths'):

    GDB_SCRIPT="../gdb-py/gdb_launch.py"   =>  Launch with target overlay-manager (part of C++ program)
    GDB_SCRIPT="../gdb-py/gdb_ovmgr_replace.py"    =>   Launch in replace target overlay-manager mode

Launch with hardware:

    cd ./launch-sh/
    ./openocd_gdb_launch.sh ../Debug/overlay_demo.elf

Launch with Spike:

    cd ./launch-sh/
    ./spike_openocd_gdb_launch.sh ../Debug/overlay_demo.elf

Example of using custom GDB-commands 'ovload ovlyno' and 'getmapped':

    (gdb) ovload 0
    section_name = .ovly0; lma = 0x10080400; size = 0x44
    Restoring binary file /home/user/workspace/overlay_demo/Debug/overlay_demo.elf into memory (0x10000060 to 0x100000a4)
    (gdb) getmapped
    Overlay #0 is mapped

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