I'm using macOS. I have downloaded sdcc for Mac and installed it followed INSTALL.txt inside the downloaded folder (simply copy it to Developer folder), and have Eclipse IDE for Embedded C/C++ Developer installed. Then I installed eclipseSDCC (I don't know if the plugin is platform specific). Seems everything in the right way.
However, when I new a project in Eclipse. I found the Toolchains is empty, so I can't create one. So, how can I deal with it?
Without knowing the prerequisites that renders a toolchain as "supported", these steps enables you to create an 8051 project:
Specify a project name.
Uncheck the checkbox at the bottom that reads "Show project types and toolchains only if they are supported on the platform".