Error:Top-level design entity “dcp_top” is undefined.

When using the Signal Tap logic analyzer remotely to debug an Accelerator Functional Unit (AFU) on an Intel® Programmable Acceleration Card (PAC) with Intel® Arria® 10 GX FPGA, you may find the AFU project not synthesized. If you compile it using Intel® Quartus Prime Pro Edition software GUI, you may get the errors as below:

Error:Top-level design entity “dcp_top” is undefined.
Can’t elaborate top-level user hierarchy
Flow failed
Quartus Prime Synthesis was unsuccessful. 3 errors, 6 warnings.

To work around this issue, you should change your project  revision from "afu_fit" to "afu_synth",  then you can use Signal Tap II Logic Analyzer to trigger on AFU signal events and capture traces of signals in your AFU design.