Convert to using LLVM code coverage

.github/workflows/test-verific.yml

@@ -44,6 +44,14 @@ jobs:
       - name: Runtime environment
         run: |
           echo "procs=$(nproc)" >> $GITHUB_ENV
+          mkdir -p "${GITHUB_WORKSPACE}/coverage"
+          echo "LLVM_PROFILE_FILE=${GITHUB_WORKSPACE}/coverage/coverage_%p.profraw" >> $GITHUB_ENV
+          echo "LLVM_PROFILE_FILE_BUFFER_SIZE=0" >> $GITHUB_ENV
+
+      - name: Skip generating files
+        if: ${{ github.event_name != 'merge_group' && github.event_name != 'workflow_dispatch' }}
+        run: |
+          echo "LLVM_PROFILE_FILE=/dev/null" >> $GITHUB_ENV
 
       - name: Build Yosys
         run: |
@@ -89,6 +97,7 @@ jobs:
         if: ${{ github.event_name == 'merge_group' || github.event_name == 'workflow_dispatch' }}
         run: |
           make coverage
+          make clean_coverage
 
       - name: Push coverage
         if: ${{ github.event_name == 'merge_group' || github.event_name == 'workflow_dispatch' }}

.gitignore

@@ -65,10 +65,10 @@
 /viz.js
 
 # other
-/coverage.info
+/yosys.profdata
+/coverage
 /coverage_html
 
-
 # these really belong in global gitignore since they're not specific to this project but rather to user tool choice
 # but too many people don't have a global gitignore configured:
 # https://docs.github.com/en/get-started/git-basics/ignoring-files#configuring-ignored-files-for-all-repositories-on-your-computer

Makefile

@@ -456,8 +456,11 @@ endif
 endif
 
 ifeq ($(ENABLE_GCOV),1)
-CXXFLAGS += --coverage
-LINKFLAGS += --coverage
+LLVM_PROFILE_FILE ?= $(realpath $(YOSYS_SRC))/coverage/coverage_%p.profraw
+export LLVM_PROFILE_FILE
+export LLVM_PROFILE_FILE_BUFFER_SIZE=0
+CXXFLAGS += -fprofile-instr-generate -fcoverage-mapping
+LINKFLAGS+= -fprofile-instr-generate
 endif
 
 ifeq ($(ENABLE_GPROF),1)
@@ -1115,13 +1118,13 @@ mrproper: clean
 
 coverage:
 	./$(PROGRAM_PREFIX)yosys -qp 'help; help -all'
-	rm -rf coverage.info coverage_html
-	lcov --capture -d . --no-external -o coverage.info
-	lcov --remove coverage.info '*/tests/various/*' '*/libs/*' -o coverage.info --ignore-errors unused
-	genhtml coverage.info --output-directory coverage_html
+	rm -rf coverage_html
+	llvm-profdata merge -sparse coverage/coverage_*.profraw -o yosys.profdata
+	llvm-cov show ./$(PROGRAM_PREFIX)yosys -instr-profile=yosys.profdata -format=html -output-dir=coverage_html --compilation-dir=. -ignore-filename-regex='(^|.*/)Verific/.*|(^|.*/)libs/.*'
 
 clean_coverage:
-	find . -name "*.gcda" -type f -delete
+	rm -rf coverage
+	rm -f yosys.profdata
 
 FUNC_KERNEL := functional.cc functional.h sexpr.cc sexpr.h compute_graph.h
 FUNC_INCLUDES := $(addprefix --include *,functional/* $(FUNC_KERNEL))
@@ -1183,7 +1186,7 @@ config-msys2-64: clean
 	echo "PREFIX := $(MINGW_PREFIX)" >> Makefile.conf
 
 config-gcov: clean
-	echo 'CONFIG := gcc' > Makefile.conf
+	echo 'CONFIG := clang' > Makefile.conf
 	echo 'ENABLE_GCOV := 1' >> Makefile.conf
 	echo 'ENABLE_DEBUG := 1' >> Makefile.conf