GHDL simulation - error: unknown warning identifier

[dboufeas]

Hello, I'm trying to run the hello world example using GHDL simulator, but I'm getting the unknown warning identifier message shown bellow.

../../../sw/lib/source/neorv32_uart.c: In function 'neorv32_uart0_setup':
../../../sw/lib/source/neorv32_uart.c:169:4: warning: #warning UART0_SIM_MODE (primary UART) enabled! Sending all UART0.TX data to text.io simulation output instead of real UART0 transmitter. Use this for simulations only! [-Wcpp]
  169 |   #warning UART0_SIM_MODE (primary UART) enabled! Sending all UART0.TX data to text.io simulation output instead of real UART0 transmitter. Use this for simulations only!
      |    ^~~~~~~
Memory utilization:
   text	   data	    bss	    dec	    hex	filename
   5040	      0	    116	   5156	   1424	main.elf
Compiling ../../../sw/image_gen/image_gen
Installing application image to ../../../rtl/core/neorv32_application_image.vhd
Simulating neorv32_application_image.vhd...
Tip: Compile application with USER_FLAGS+=-DUART[0/1]_SIM_MODE to auto-enable UART[0/1]'s simulation mode (redirect UART output to simulator console).
Using simulation runtime args: --stop-time=10ms
/usr/bin/ghdl-mcode:error: unknown warning identifier
make: *** [../../../sw/common/common.mk:287: sim] Error 1

I am using make USER_FLAGS+=-DUART0_SIM_MODE MARCH=rv32imc clean_all sim to start the simulation.

Any ideas why this is happening?

EDIT: if I remove -Wall option from ghdl command in ghdl.run.sh file the program runs as expected:

runcmd="$GHDL -r -Wall --work=neorv32 --workdir=build neorv32_tb_simple \
  --max-stack-alloc=0 \
  --ieee-asserts=disable \
  --assert-level=error $GHDL_RUN_ARGS"

[stnolting]

Hey!

I will remove the -Wall flag again. Thanks for the hint!

Any ideas why this is happening?

I have no idea. I will check that again. But maybe this is something we should report/ask to GHDL.

[Ugenix]

Hi! I´m following the User Guide for NEORV32 Processor and when I try simulation with sw/example/demo_blink_led$ make USER_FLAGS+=-DUART0_SIM_MODE clean_all sim I get this error:

/usr/bin/ghdl-mcode:info: simulation stopped by --stop-time @10ms
make: ** [../../../sw/common/common.mk:296: sim] Error 1

I have looked at the ghdl.run.sh file and the -Wall flag is removed. So I do not know why this error happens and how it can be resolved.

However, if I try Hello World! simulation using sw/example/hello_world$ make USER_FLAGS+=-DUART0_SIM_MODE MARCH=rv32i_zicsr clean_all sim the simulation run correctly.

Thank you in advance.

[stnolting]

Hey there!

This is not a real error. The simulation is auto terminated after a specific time (10ms by default).

neorv32/sim/simple/ghdl.run.sh

Line 27 in 8e52234

GHDL_RUN_ARGS="${@:---stop-time=10ms}"

The standard simulation scripts that can be called from the Makefile were originally used to run the processor's verification testbench. They scan a speicific file for a specific string and if that string is not found the script return an error condition.

neorv32/sim/simple/ghdl.run.sh

Lines 45 to 46 in 8e52234

	# verify results of processor check: sw/example/processor_check
	cat neorv32.uart0.sim_mode.text.out | grep "PROCESSOR TEST COMPLETED SUCCESSFULLY!"

Maybe we should change this to be less application specifci, but right now I am not sure how to do that.

Anyway, you can safely ignore that. 😉 If there's a "real" VHDL bug GHDL will still show that in the console.