Document known issues in ISSUES.md

ISSUES.md

+# Maximum number of FIUs/Test cases
+
+While the code within FIJI does not impose limitations on the number
+of Fault Injection Units (FIUs) test cases in configuration files,
+the GUI framework used for FIJI Setup and FIJI EE (Tk) as of 2017
+contains some bugs that might make it impossible to display a high
+number of GUI elements on screen. Some installations have been affected
+by this and could not display more than about 300 FIUs.
+The only known workaround is to edit the configuration files by hand for
+all FIUs greater than this limit.
+
+
+# No support for multiple instances of the same module
+
+Currently FIJI does only support single instances of modules. However,
+no netlist observed so far uses multiple instances of a single module.
+
+Additionally, FIJI prints the driver path only as "module/pathname"
+which is inconsistent with the full hierarchical path of the net itself.
+
+What could be done:
+
+* Print out the full hierarchical path of the driver.
+  However, this might lead the user to think that FIJI actually supports
+  multiple instances of a module.
+* Check for duplicate modules when loading a netlist.
+* Check for duplicate modules when validating a driver (by searching for
+  a duplicate of the respective module at runtime or by comparing it
+  with a list of duplicate modules created at netlist load time).
+* Add support for duplicate modules.
+  This would require to instrument the copy of a module.
+
+
+# Verilog vs. VHDL
+
+While FIJI expects Verilog netlists as input, many files generated by
+it such as the top wrapper, FIC and FIUs are coded in VHDL only. Thus
+any tools that have to process the instrumented netlist and these
+generated files together (e.g., for synthesis) have to support both,
+Verilog and VHDL.

README.md

@@ -45,6 +45,8 @@ The following documents are available:
  - API documentation about the source code of FIJI can be built with Doxygen by executing `make -C ./docs/ doxygen`.
     It requires `doxygen-filter-perl` to be available (provided by Perl's `Doxygen::Filter::Perl` package).
 
+ - Know issues and limitations are documented in the [`ISSUES`](/ISSUES.md) file.
+
 ## Installation
 
 Since FIJI requires a relatively sane Verilog netlist as input, using Synopsis Synplify is recommended and thus needs to be installed.