Recently I came across a quite difficult problem during setting up a debug configuration for my STM32 ARM development environment in Eclipse.
When I was running a I always got „file not found” error in GDB console.
GDB error:
Function "0x8000000" not defined. No source file named C:\\ARM\\workspace\\blinky\\src\\main.c.
Solution:
Go to your Debug Configuration -> Configure Workspace Settings

Expand Run/Debug -> Launching -> Default Launchers
Select GDB Hardware debugging -> Debug (or Release depending on your Configurations)
Select option Legacy GDB Hardware Debugging Launcher
Then click Apply and OK

Then click Apply and OK
Now debug should work without any problems.
Related links:
http://stackoverflow.com/questions/19864204/eclipse-mingw-cdt-gdb-and-problems-with-debugging

