SourceLevelDebugPkg

This package includes a source code debugger agent into a platform, which connects over COM or USB debug ports. This plus a debug host application will allow source level debugging of UEFI drivers and UEFI applications.

https://github.com/tianocore/edk2/tree/master/SourceLevelDebugPkg

Host debug applications for Microsoft Windows and Linux are available here: https://software.intel.com/en-us/articles/unified-extensible-firmware-interface Also uses the UEFI Connection with Intel® System Studio Debugger here: https://software.intel.com/en-us/system-studio/choose-download

Info for debugging with gdb is available here: How to debug OVMF with QEMU using GDB