Coverage Guide

Line, branch, and toggle code coverage collection and reporting.

RyuSim supports line, branch, and toggle code coverage. Pass coverage flags via your cocotb Makefile.

Enable coverage

Add coverage flags to EXTRA_ARGS in your Makefile:

SIM            ?= ryusim
TOPLEVEL_LANG  := verilog

VERILOG_SOURCES = $(PWD)/counter.sv
TOPLEVEL        = counter
COCOTB_TEST_MODULES = test_counter

# Enable coverage collection
EXTRA_ARGS += --coverage --coverage-file=coverage.info

include $(shell cocotb-config --makefiles)/Makefile.sim

Then run as usual:

make

Coverage types (use in EXTRA_ARGS):

--coverage — Full coverage (line, branch, toggle)
--coverage-line — Line coverage only (fastest)
--coverage-branch — Branch coverage
--coverage-toggle — Toggle coverage

View results

Requires the lcov package (sudo apt install lcov or brew install lcov).

genhtml coverage.info -o coverage_html

Merge coverage

Combine coverage data from multiple test runs into a single report:

ryusim coverage merge -o merged.info test1.info test2.info