Add llvm-snippy random test generator flow

dv/uvm/core_ibex/CMakeLists.txt

@@ -0,0 +1,16 @@
+cmake_minimum_required(VERSION 3.20)
+
+project(IbexSnippyFlow LANGUAGES NONE)
+
+include(${CMAKE_CURRENT_SOURCE_DIR}/snippy_cmake/Helpers.cmake)
+include(${CMAKE_CURRENT_SOURCE_DIR}/snippy_cmake/IbexMake.cmake)
+include(${CMAKE_CURRENT_SOURCE_DIR}/snippy_cmake/Options.cmake)
+include(${CMAKE_CURRENT_SOURCE_DIR}/snippy_cmake/Paths.cmake)
+include(${CMAKE_CURRENT_SOURCE_DIR}/snippy_cmake/Inputs.cmake)
+include(${CMAKE_CURRENT_SOURCE_DIR}/snippy_cmake/RiscvDv.cmake)
+include(${CMAKE_CURRENT_SOURCE_DIR}/snippy_cmake/RtlCompile.cmake)
+include(${CMAKE_CURRENT_SOURCE_DIR}/snippy_cmake/Cosimulation.cmake)
+include(${CMAKE_CURRENT_SOURCE_DIR}/snippy_cmake/SnippyCommands.cmake)
+include(${CMAKE_CURRENT_SOURCE_DIR}/snippy_cmake/Snippy.cmake)
+include(${CMAKE_CURRENT_SOURCE_DIR}/snippy_cmake/Coverage.cmake)
+include(${CMAKE_CURRENT_SOURCE_DIR}/snippy_cmake/FlowTargets.cmake)

dv/uvm/core_ibex/Makefile

@@ -52,6 +52,15 @@ IBEX_CONFIG         := opentitan
 # Path to DUT used for coverage reports
 DUT_COV_RTL_PATH    := "ibex_top"
 
+# Optional override for compressed extension subset.
+# Empty means: use RV32ZC from IBEX_CONFIG in ibex_configs.yaml.
+# Allowed values:
+#   ibex_pkg::RV32Zca
+#   ibex_pkg::RV32ZcaZcb
+#   ibex_pkg::RV32ZcaZcmp
+#   ibex_pkg::RV32ZcaZcbZcmp
+RV32ZC :=
+
 export EXTRA_COSIM_CFLAGS ?=
 
 ifeq ($(COSIM_SIGSEGV_WORKAROUND), 1)
@@ -76,9 +85,23 @@ run:
 	  SEED=$(SEED) WAVES=$(WAVES) COV=$(COV) SIMULATOR=$(SIMULATOR) \
 	  ISS=$(ISS) TEST=$(TEST) VERBOSE=$(VERBOSE) ITERATIONS=$(ITERATIONS) \
 	  SIGNATURE_ADDR=$(SIGNATURE_ADDR) IBEX_CONFIG=$(IBEX_CONFIG) \
+	  RV32ZC=$(RV32ZC) \
 	  DUT_COV_RTL_PATH=$(DUT_COV_RTL_PATH)"
 	@$(MAKE) --file wrapper.mk --environment-overrides --no-print-directory $(GOAL)
 
+# Run a wrapper.mk goal using already-created metadata.
+#
+# This is intended for external flows, such as the Snippy CMake flow, where
+# metadata is created once by an earlier Ibex Make invocation and many simulator
+# runs are launched afterwards. It preserves the top-level Makefile derived
+# variables such as OUT-DIR, METADATA-DIR and PYTHONPATH, but avoids calling
+# metadata.py --op create_metadata for every individual run.
+.PHONY: run_existing_metadata
+run_existing_metadata:
+	@test -f $(METADATA-DIR)/metadata.pickle || \
+	  (echo "Metadata not found: $(METADATA-DIR)/metadata.pickle. Run make run GOAL=rtl_tb_compile first."; false)
+	@$(MAKE) --file wrapper.mk --environment-overrides --no-print-directory $(GOAL)
+
 ###############################################################################
 
 # This is the top-level output directory. Everything we generate goes in
@@ -94,6 +117,94 @@ export METADATA-DIR := $(OUT-DIR)metadata
 # riscv-dv extension directory
 export EXT_DIR             := riscv_dv_extension
 
+###############################################################################
+# Snippy CMake flow
+#
+# The Snippy flow is implemented in CMake under snippy_cmake/. This Makefile
+# block is intentionally a thin bridge:
+#
+#   Ibex Make knobs  ->  CMake cache variables  ->  Snippy CMake flow
+#
+# Toolchain and Spike variables are shared with the normal Ibex flow:
+#
+#   RISCV_GCC
+#   RISCV_OBJCOPY
+#   SPIKE_PATH
+#   PKG_CONFIG_PATH
+#
+# Snippy runs write their standard Ibex-compatible runtime artifacts into
+# $(OUT-DIR), so later Ibex coverage goals can consume them together with
+# normal riscv-dv results.
+
+# Comma-separated list of Snippy YAML layouts to run, for example:
+#
+#   SNIPPY_TEST="layout_arith, jalr, rem_div"
+#
+# Empty means: use the CMake flow default selection.
+SNIPPY_TEST ?=
+
+# Number of Snippy runs for each selected YAML layout.
+SNIPPY_ITERATIONS ?= 1
+
+# Directory with Snippy YAML layout files.
+# Relative paths are resolved by CMake from dv/uvm/core_ibex.
+SNIPPY_YAML_DIR ?= snippy/yaml_tests
+
+# Placeholder metadata test name used by the Snippy CMake flow when creating
+# Ibex metadata. Keep this separate from TEST so normal riscv-dv Make runs can
+# keep using TEST=all or any user-selected riscv-dv test.
+SNIPPY_METADATA_TEST ?= snippy_func_test
+
+# Use snippy/urg_exclude/urg_exclude_all.txt during VCS/URG coverage merge.
+USE_URG_EXCLUDE ?= ON
+
+# CMake source and build directories for the Snippy flow.
+#
+# CMakeLists.txt is expected to live in this core_ibex directory and include the
+# implementation files from snippy_cmake/.
+SNIPPY_CMAKE_SOURCE_DIR ?= $(CURDIR)
+SNIPPY_CMAKE_BUILD_DIR  ?= $(OUT-DIR)snippy_cmake_build
+
+# Do not let the top-level Ibex VERBOSE=0 leak into CMake-generated Makefiles:
+# for them, any non-empty VERBOSE value enables command echoing. Pass VERBOSE=1
+# to the native build tool only when the user explicitly requested it.
+SNIPPY_CMAKE_BUILD_NATIVE_ARGS := --no-print-directory
+ifeq ($(VERBOSE),1)
+SNIPPY_CMAKE_BUILD_NATIVE_ARGS += VERBOSE=1
+endif
+
+.PHONY: configure_snippy
+configure_snippy:
+	cmake -S $(SNIPPY_CMAKE_SOURCE_DIR) -B $(SNIPPY_CMAKE_BUILD_DIR) \
+	  -DOUT=$(abspath $(OUT-DIR)) \
+	  -DSEED=$(SEED) \
+	  -DWAVES=$(WAVES) \
+	  -DCOV=$(COV) \
+	  -DSIMULATOR=$(SIMULATOR) \
+	  -DISS=$(ISS) \
+	  -DTEST=$(SNIPPY_METADATA_TEST) \
+	  -DIBEX_CONFIG=$(IBEX_CONFIG) \
+	  -DRV32ZC=$(RV32ZC) \
+	  -DSIGNATURE_ADDR=$(SIGNATURE_ADDR) \
+	  -DRISCV_GCC="$(RISCV_GCC)" \
+	  -DRISCV_OBJCOPY="$(RISCV_OBJCOPY)" \
+	  -DSPIKE_PATH="$(SPIKE_PATH)" \
+	  -DPKG_CONFIG_PATH="$(PKG_CONFIG_PATH)" \
+	  -DSNIPPY_ITERATIONS=$(SNIPPY_ITERATIONS) \
+	  -DSNIPPY_TEST="$(SNIPPY_TEST)" \
+	  -DYAML_DIR="$(SNIPPY_YAML_DIR)" \
+	  -DUSE_URG_EXCLUDE=$(USE_URG_EXCLUDE)
+
+.PHONY: run_snippy
+run_snippy: configure_snippy
+	env -u VERBOSE cmake --build $(SNIPPY_CMAKE_BUILD_DIR) --target run_all -j 60 -- $(SNIPPY_CMAKE_BUILD_NATIVE_ARGS)
+
+.PHONY: coverage_snippy
+coverage_snippy:
+	@test -d $(SNIPPY_CMAKE_BUILD_DIR) || \
+	  (echo "Snippy CMake build directory not found: $(SNIPPY_CMAKE_BUILD_DIR). Run make run_snippy first."; false)
+	env -u VERBOSE cmake --build $(SNIPPY_CMAKE_BUILD_DIR) --target coverage -- $(SNIPPY_CMAKE_BUILD_NATIVE_ARGS)
+
 ###############################################################################
 
 .PHONY: clean

dv/uvm/core_ibex/README.md

@@ -27,9 +27,118 @@ export RISCV_GCC=riscv32-unknown-elf-gcc
 export RISCV_OBJCOPY=riscv32-unknown-elf-objcopy
 ```
 
+For the optional llvm-snippy flow, set `SC_SNIPPY_PATH` to the llvm-snippy
+installation directory:
+
+```bash
+export SC_SNIPPY_PATH=/path/to/llvm-snippy
+```
+
+The Snippy flow expects the executable at `$SC_SNIPPY_PATH/llvm-snippy`.
+More Snippy-specific setup notes are documented in `snippy_cmake/README.md`.
+
 ## Running tests
 
 To run tests you can make variations of the following command, where you replace `$TEST_NAME` with the test (or a series of comma-separated tests) that you would like to run as specified in `dv/uvm/core_ibex/riscv_dv_extension/testlist.yaml`:
 ```bash
 make --keep-going IBEX_CONFIG=opentitan SIMULATOR=xlm ISS=spike ITERATIONS=1 SEED=1 TEST=$TEST_NAME WAVES=0 COV=0
+```
+
+## Running Snippy tests
+
+The custom Snippy flow can be launched through the Ibex Makefile with
+`run_snippy`.
+
+Example:
+
+```bash
+make run_snippy \
+  OUT=out \
+  COV=1 \
+  SIMULATOR=vcs \
+  IBEX_CONFIG=opentitan \
+  RV32ZC=ibex_pkg::RV32Zca \
+  SNIPPY_ITERATIONS=3 \
+  SNIPPY_TEST="layout_arith, jalr, rem_div" \
+  SNIPPY_YAML_DIR=snippy/yaml_tests
+```
+
+`SNIPPY_TEST` selects YAML files from `SNIPPY_YAML_DIR`.
+
+`SNIPPY_TEST` is a comma-separated list of Snippy YAML layouts. The accepted
+forms include `layout_arith`, `arith`, and `layout_arith.yaml`.
+
+`SNIPPY_ITERATIONS` controls the number of Snippy runs for each selected layout.
+
+Snippy runtime results are written into the standard Ibex output tree:
+
+```text
+out/run/tests/snippy_<layout>.<seed>/
+```
+
+The CMake-side Snippy intermediate files and summary are written under:
+
+```text
+out/snippy_cmake_build/
+```
+
+## Collecting combined riscv-dv and Snippy coverage
+
+To collect one combined coverage report from both riscv-dv and Snippy runs, use
+the same `OUT` directory and enable `COV=1` for both flows.
+
+First, run riscv-dv only up to RTL simulation:
+
+```bash
+make run \
+  GOAL=rtl_sim_run \
+  OUT=out \
+  COV=1 \
+  SIMULATOR=vcs \
+  IBEX_CONFIG=opentitan \
+  RV32ZC=ibex_pkg::RV32Zca \
+  TEST=riscv_arithmetic_basic_test
+```
+
+Using `GOAL=rtl_sim_run` avoids collecting an intermediate coverage report
+before the Snippy tests have been added.
+
+Then run Snippy into the same `OUT` directory:
+
+```bash
+make run_snippy \
+  OUT=out \
+  COV=1 \
+  SIMULATOR=vcs \
+  IBEX_CONFIG=opentitan \
+  RV32ZC=ibex_pkg::RV32Zca \
+  SNIPPY_ITERATIONS=3 \
+  SNIPPY_TEST="layout_arith, jalr, rem_div"
+```
+
+Finally, merge coverage once:
+
+```bash
+make coverage_snippy OUT=out
+```
+
+The final report is written to:
+
+```text
+out/run/coverage/report/
+```
+
+## Cleaning generated files
+
+To remove generated outputs:
+
+```bash
+make clean OUT=out
+```
+
+This also removes the Snippy CMake build directory when it is located under
+`OUT`, for example:
+
+```text
+out/snippy_cmake_build/
 ```