Confirmation of Program Operation in Release build

[pass3master]

Confirmation of Program Operation in Release build
We are trying to verify the operation of the program in the Release build. However, when we do [Build with Release] → [Change Debug Configuration(Select the application Release/***.elf)] → [Debug], we get the following message.
What is wrong?

No source available for “main() at 0x8002978”

By the way, I can check the operation of the debug build without any problem.

[KnarfB · Accepted solution]

there is nothing wrong. Your Release config doesn't generate debug information for source level debugging so you are stuck at assembly level. 

There are options to combine release type code optimization and including some minimal debug info. The details depend on your compiler / IDE. 

hth

KnarfB