Files
PeakRDL-BusDecoder/tests/generator/test_questa_compatibility.py
Copilot 3d823572cc Fix nonconstant index errors in Questa by using unpacked structs and interface array intermediates (#17)
* Initial plan

* Fix nonconstant index error by using unpacked structs and arrays

Co-authored-by: arnavsacheti <36746504+arnavsacheti@users.noreply.github.com>

* Add comprehensive tests for Questa compatibility with instance arrays

Co-authored-by: arnavsacheti <36746504+arnavsacheti@users.noreply.github.com>

* Add intermediate signals for interface array fanin to fix Questa compatibility

Questa simulator rejects indexing interface arrays with non-constant variables in procedural blocks (always_comb). This fix creates intermediate unpacked array signals that are assigned from interface arrays using generate loops (with genvar), then references those intermediates in the fanin logic.

Changes:
- Added fanin_intermediate_gen.py to generate intermediate signals
- Modified APB3/APB4/AXI4-Lite cpuif classes to use intermediates for interface arrays
- Updated templates to include intermediate signal section
- Intermediate signals use genvar indexing (legal) instead of variable indexing (illegal in Questa)

Co-authored-by: arnavsacheti <36746504+arnavsacheti@users.noreply.github.com>

* Fix type checking and formatting issues in fanin intermediate generator

- Added proper null checks for node.array_dimensions to avoid type errors
- Used getattr() to safely access is_interface and _interface attributes
- Added early returns when interface is None to prevent errors
- Fixed formatting issues in fanin_intermediate_gen.py
- All type checks now pass (only pre-existing errors remain in other files)
- All 67 tests still pass

Co-authored-by: arnavsacheti <36746504+arnavsacheti@users.noreply.github.com>

* Fix test collection when cocotb is not installed

The cocotb test files (test_runner.py) have imports that fail at module level when cocotb is not installed, causing pytest collection to fail. This prevents running tests in environments without cocotb dependencies.

Solution: Updated conftest.py to conditionally ignore cocotb tests when cocotb is not available, allowing tests to pass in both environments (with and without cocotb).

- When cocotb is available: only ignore test_register_access.py files (existing behavior)
- When cocotb is not available: ignore all files under cocotb/** directories

This allows CI to run all 67 non-simulation tests successfully without requiring cocotb/verilator dependencies for basic testing.

Co-authored-by: arnavsacheti <36746504+arnavsacheti@users.noreply.github.com>

* add default for unpacked struct

* cocotb is test dependancy

* Refactor fanin intermediate signal logic to cpuif level

Moved the interface-specific signal assignment logic from fanin_intermediate_gen.py to individual cpuif classes (APB3Cpuif, APB4Cpuif, AXI4LiteCpuif). This follows better architecture principles where each cpuif knows which signals it needs.

Changes:
- Added fanin_intermediate_assignments() method to BaseCpuif
- Implemented fanin_intermediate_assignments() in APB3Cpuif, APB4Cpuif, and AXI4LiteCpuif
- Updated FaninIntermediateGenerator to call the cpuif method instead of checking interface type
- Removed interface type checking logic from fanin_intermediate_gen.py

This makes the code more maintainable and follows the single responsibility principle - each cpuif class knows its own signal requirements.

Co-authored-by: arnavsacheti <36746504+arnavsacheti@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: arnavsacheti <36746504+arnavsacheti@users.noreply.github.com>
2025-10-28 22:03:57 -07:00

132 lines
4.4 KiB
Python

"""Test Questa simulator compatibility for instance arrays."""
from collections.abc import Callable
from pathlib import Path
from tempfile import TemporaryDirectory
from systemrdl.node import AddrmapNode
from peakrdl_busdecoder import BusDecoderExporter
from peakrdl_busdecoder.cpuif.apb4 import APB4Cpuif
def test_instance_array_questa_compatibility(compile_rdl: Callable[..., AddrmapNode]) -> None:
"""Test that instance arrays generate Questa-compatible code.
This test ensures that:
- Struct members for arrays use unpacked array syntax (name[dim])
- NOT packed bit-vector syntax ([dim-1:0]name)
- Struct is unpacked (not packed)
- Array indexing with loop variables works correctly
This fixes the error: "Nonconstant index into instance array"
"""
rdl_source = """
addrmap test_map {
reg {
field {
sw=rw;
hw=r;
} data[31:0];
} my_reg[4] @ 0x0 += 0x10;
};
"""
top = compile_rdl(rdl_source, top="test_map")
with TemporaryDirectory() as tmpdir:
exporter = BusDecoderExporter()
exporter.export(top, tmpdir, cpuif_cls=APB4Cpuif)
# Read the generated module
module_file = Path(tmpdir) / "test_map.sv"
content = module_file.read_text()
# Should use unpacked struct
assert "typedef struct {" in content
assert "typedef struct packed" not in content
# Should use unpacked array syntax for array members
assert "logic my_reg[4];" in content
# Should NOT use packed bit-vector syntax
assert "[3:0]my_reg" not in content
# Should have proper array indexing in decode logic
assert "cpuif_wr_sel.my_reg[i0] = 1'b1;" in content
assert "cpuif_rd_sel.my_reg[i0] = 1'b1;" in content
# Should have proper array indexing in fanout/fanin logic
assert "cpuif_wr_sel.my_reg[gi0]" in content or "cpuif_rd_sel.my_reg[gi0]" in content
assert "cpuif_wr_sel.my_reg[i0]" in content or "cpuif_rd_sel.my_reg[i0]" in content
def test_multidimensional_array_questa_compatibility(compile_rdl: Callable[..., AddrmapNode]) -> None:
"""Test that multidimensional instance arrays generate Questa-compatible code."""
rdl_source = """
addrmap test_map {
reg {
field {
sw=rw;
hw=r;
} data[31:0];
} my_reg[2][3] @ 0x0 += 0x10;
};
"""
top = compile_rdl(rdl_source, top="test_map")
with TemporaryDirectory() as tmpdir:
exporter = BusDecoderExporter()
exporter.export(top, tmpdir, cpuif_cls=APB4Cpuif)
# Read the generated module
module_file = Path(tmpdir) / "test_map.sv"
content = module_file.read_text()
# Should use unpacked struct with multidimensional array
assert "typedef struct {" in content
# Should use unpacked array syntax for multidimensional arrays
assert "logic my_reg[2][3];" in content
# Should NOT use packed bit-vector syntax
assert "[1:0][2:0]my_reg" not in content
assert "[5:0]my_reg" not in content
def test_nested_instance_array_questa_compatibility(compile_rdl: Callable[..., AddrmapNode]) -> None:
"""Test that nested instance arrays generate Questa-compatible code."""
rdl_source = """
addrmap inner_map {
reg {
field {
sw=rw;
hw=r;
} data[31:0];
} inner_reg[2] @ 0x0 += 0x10;
};
addrmap outer_map {
inner_map inner[3] @ 0x0 += 0x100;
};
"""
top = compile_rdl(rdl_source, top="outer_map")
with TemporaryDirectory() as tmpdir:
exporter = BusDecoderExporter()
exporter.export(top, tmpdir, cpuif_cls=APB4Cpuif)
# Read the generated module
module_file = Path(tmpdir) / "outer_map.sv"
content = module_file.read_text()
# Should use unpacked struct
assert "typedef struct {" in content
# Inner should be an array
# The exact syntax may vary, but it should be unpacked
# Look for the pattern of unpacked arrays, not packed bit-vectors
assert "inner[3]" in content or "logic inner" in content
# Should NOT use packed bit-vector syntax like [2:0]inner
assert "[2:0]inner" not in content