In the Nios II IDE, the method is to create an .objdump file and check the memory mapping information in the generated file.

The method for generating the objdump file is shown below.

• Click Preferences on the Windows menu of the Nios II IDE
• Select Nios II on the left, check Generate objdump file on the right and click OK
• Running Build generates a file with the extension *.objdump

Please refer to the URL below for information on how to generate an objdump file.
https://www.altera.com/support/support-resources/knowledge-base/solutions/rd05042004_4822.html