feat(bench): automate running benchmarks (#122)

Author: BrandonPacewic

Makefile

@@ -33,6 +33,9 @@ bench: BUILD_BENCH := ON
 bench: build
 	@cmake --build "$(BUILD_DIR)" -j$(JOBS)
 
+run-benchmarks: bench
+	@cmake --build "$(BUILD_DIR)" --target run_all_benchmarks -- -j$(JOBS)
+
 tools: BUILD_TOOLS := ON
 tools: build
 
@@ -50,6 +53,7 @@ help:
 	@echo "  build              - configure and build"
 	@echo "  test               - run ctest (RUN_TESTS=ON)"
 	@echo "  bench              - build & run benchmarks (BUILD_BENCH=ON)"
+	@echo "  run-benchmarks     - run all benchmarks"
 	@echo "  tools              - build project-defined tools (BUILD_TOOLS=ON)"
 	@echo "  format             - run clang-format on all source files"
 	@echo "  clean              - clean build artefacts"

benchmarks/CMakeLists.txt

@@ -39,6 +39,39 @@ foreach(BENCHMARK_FILE ${BENCHMARK_FILES})
     add_executable(${FINAL_TARGET_NAME} ${BENCHMARK_FILE})
     set_target_properties(${FINAL_TARGET_NAME} PROPERTIES RUNTIME_OUTPUT_DIRECTORY ${BENCHMARK_BINARY_DIR})
     target_link_libraries(${FINAL_TARGET_NAME} PRIVATE cpl benchmark::benchmark)
+
+    list(APPEND BENCHMARK_TARGETS ${FINAL_TARGET_NAME})
+endforeach()
+
+execute_process(
+  COMMAND git rev-parse --short HEAD
+  WORKING_DIRECTORY "${CMAKE_SOURCE_DIR}"
+  OUTPUT_VARIABLE GIT_HASH
+  OUTPUT_STRIP_TRAILING_WHITESPACE
+)
+
+string(TIMESTAMP TODAY "%Y-%m-%d_%H-%M-%S")
+set(RESULT_DIR "${CMAKE_BINARY_DIR}/benchmarks/results")
+file(MAKE_DIRECTORY "${RESULT_DIR}")
+set(BENCH_JSONS "")
+
+foreach(TGT IN LISTS BENCHMARK_TARGETS)
+  set(JSON_OUT "${RESULT_DIR}/${TODAY}_${GIT_HASH}_${TGT}.json")
+
+    add_custom_command(
+    OUTPUT  "${JSON_OUT}"
+    COMMAND ${CMAKE_COMMAND} -E echo "→ running ${TGT}"
+    COMMAND $<TARGET_FILE:${TGT}>
+            --benchmark_out=${JSON_OUT}
+            --benchmark_out_format=json
+    DEPENDS ${TGT}
+    COMMENT "Running benchmark '${TGT}' and writing ${JSON_OUT}"
+    VERBATIM
+    )
+
+  list(APPEND BENCH_JSONS "${JSON_OUT}")
 endforeach()
 
+add_custom_target(run_all_benchmarks ALL DEPENDS ${BENCH_JSONS})
+
 include_directories(BEFORE ${CMAKE_SOURCE_DIR}/cpl/inc)