VPI Unconstrained Array Bug

[gbowers4]

Description

GHDL 4.0.0 Recently added support for unconstrained array typedefs in VHDL, however as it seems this features hasn't been tested in cocotb and a bug occurs. when a constrained array is read from/written to GHDL performs the same as any other simulator, however when the dimensions of the array type is unconstrained a cocotb GPI error occurs.

How to reproduce?

Test

@cocotbTest()
async def run(dut):
    """
        Template Test program
    """
    print(dut.test_constrained[0].value)
    print(dut.test_unconstrained[0].value)

library ieee;
use ieee.std_logic_1164.all;
use ieee.numeric_std.all;

entity rtl_bench is
port(
  clk : in std_logic
);
end rtl_bench;

architecture arch of rtl_bench is

  type constrained_array_t is array (0 to 3) of std_logic_vector(7 downto 0);
  type unconstrained_array_t is array (integer range <>) of std_logic_vector;
  signal test_constrained   : constrained_array_t := (others => x"ba");
  signal test_unconstrained : unconstrained_array_t (0 to 3)(7 downto 0) := (others => x"ba");


begin

end arch;

Output

INFO     cocotb:simulator.py:305      0.00ns DEBUG    gpi                                VPI: Created GPI object from type ???(114)
INFO     cocotb:simulator.py:305      0.00ns DEBUG    gpi                                Checking rtl_bench.test_constrained exists
INFO     cocotb:simulator.py:305      0.00ns DEBUG    cocotb.test_constrained            Created
INFO     cocotb:simulator.py:305      0.00ns DEBUG    gpi                                Checking if index 0 native through implementation VPI
INFO     cocotb:simulator.py:305      0.00ns DEBUG    gpi                                VPI: Indexable object initialized with range [7:0] and length >8<
INFO     cocotb:simulator.py:305      0.00ns DEBUG    gpi                                VPI: test_constrained[0] initialized with 8 elements
INFO     cocotb:simulator.py:305      0.00ns DEBUG    gpi                                VPI: Created GPI object from type ???(36)
INFO     cocotb:simulator.py:305      0.00ns DEBUG    gpi                                Checking rtl_bench.test_constrained[0] exists
INFO     cocotb:simulator.py:305      0.00ns DEBUG    cocotb.test_constrained[0]         Created
INFO     cocotb:simulator.py:305 10111010
INFO     cocotb:simulator.py:305      0.00ns DEBUG    gpi                                Searching for test_unconstrained
INFO     cocotb:simulator.py:305      0.00ns DEBUG    gpi                                VPI: Created GPI object from type ???(114)
INFO     cocotb:simulator.py:305      0.00ns DEBUG    gpi                                Checking rtl_bench.test_unconstrained exists
INFO     cocotb:simulator.py:305      0.00ns DEBUG    cocotb.test_unconstrained          Created
INFO     cocotb:simulator.py:305      0.00ns DEBUG    gpi                                Checking if index 0 native through implementation VPI
INFO     cocotb:simulator.py:305      0.00ns DEBUG    gpi                                Unable to find handle through vpi_handle_by_index(), attempting second method
INFO     cocotb:simulator.py:305      0.00ns DEBUG    gpi                                Unable to vpi_get_handle_by_index test_unconstrained[0]
INFO     cocotb:simulator.py:305      0.00ns WARNING  gpi                                Failed to find a handle at index 0 via any registered implementation
INFO     cocotb:simulator.py:305      0.00ns TRACE    gpi                                Returning to simulator
INFO     cocotb:simulator.py:305      0.00ns TRACE    gpi                                Returning control to simulator
INFO     cocotb:simulator.py:305      0.00ns TRACE    gpi                                Passing control to GPI user
INFO     cocotb:simulator.py:305      0.00ns TRACE    gpi                                Returning to Python
INFO     cocotb:simulator.py:305      0.00ns INFO     cocotb.regression                  run failed
INFO     cocotb:simulator.py:305                                                         Traceback (most recent call last):
INFO     cocotb:simulator.py:305                                                           File "/data/firmware/src/pylib/cocotb/templates/avl_st_template/avl_st_template_test.py", line 43, in run
INFO     cocotb:simulator.py:305                                                             print(dut.test_unconstrained[0].value)
INFO     cocotb:simulator.py:305                                                           File "/usr/local/lib/python3.10/dist-packages/cocotb/handle.py", line 652, in __getitem__
INFO     cocotb:simulator.py:305                                                             raise IndexError(
INFO     cocotb:simulator.py:305                                                         IndexError: test_unconstrained(GPI_ARRAY) contains no object at index 0

Context

• GHDL 4.0.0 Built from GCC
• cocotb 1.8.1
• Ubuntu 22.04