I am trying to go "all free" regarding the price for the software. So I decided to develop my code for STM32F0 in Eclipse and in Ubuntu.
I tried with different options regarding adding ARM toolchain to Eclipse. The best I find is to download the special Eclipse version http://www.openstm32.org.
But It has some flaws regarding the compiler. Is there a way to add/import a Keil compiler to Eclipse IDE?
Because the same code worked on Keil very well.
I faced similar problem some time ago. topic on KEIL forum about Linux enviroment
Anyway there are some older info here: quite strict answer from KEIL
I would suggest you to try go deeper if you really want to go "all free". Setup manually arm-gcc compiler, debugger (openOCD) and write own customized Makefile. Eclipse is an IDE which uses external compiler and debugger(so it's almost a text editor), the only thing it do is auto-generates Makefile- amd that may be a problem in some cases. It may be that not the compiler issues you a problems,but auto-generated Makefile from Eclipse, (wrong linker,lib flags or etc).
Anyway it is not the easy way, but you can find easily lots of pre-made Makefiles over github and with minimal customization you could load your project freshly.
And yes, there are differences between KEIL compiler for ARM and ARM-GCC. With standard libs, optimization and etc, those differences also may be a problem for you project.