benchmark/test/AssemblyTests.cmake
Eric 7b03df7ff7
Add tests to verify assembler output -- Fix DoNotOptimize. (#530)
* Add tests to verify assembler output -- Fix DoNotOptimize.

For things like `DoNotOptimize`, `ClobberMemory`, and even `KeepRunning()`,
it is important exactly what assembly they generate. However, we currently
have no way to test this. Instead it must be manually validated every
time a change occurs -- including a change in compiler version.

This patch attempts to introduce a way to test the assembled output automatically.
It's mirrors how LLVM verifies compiler output, and it uses LLVM FileCheck to run
the tests in a similar way.

The tests function by generating the assembly for a test in CMake, and then
using FileCheck to verify the // CHECK lines in the source file are found
in the generated assembly.

Currently, the tests only run on 64-bit x86 systems under GCC and Clang,
and when FileCheck is found on the system.

Additionally, this patch tries to improve the code gen from DoNotOptimize.
This should probably be a separate change, but I needed something to test.

* Disable assembly tests on Bazel for now

* Link FIXME to github issue

* Fix Tests on OS X

* fix strip_asm.py to work on both Linux and OS X like targets
2018-03-23 16:10:47 -06:00

46 lines
1.4 KiB
CMake

set(ASM_TEST_FLAGS "")
check_cxx_compiler_flag(-O3 BENCHMARK_HAS_O3_FLAG)
if (BENCHMARK_HAS_O3_FLAG)
list(APPEND ASM_TEST_FLAGS -O3)
endif()
check_cxx_compiler_flag(-g0 BENCHMARK_HAS_G0_FLAG)
if (BENCHMARK_HAS_G0_FLAG)
list(APPEND ASM_TEST_FLAGS -g0)
endif()
check_cxx_compiler_flag(-fno-stack-protector BENCHMARK_HAS_FNO_STACK_PROTECTOR_FLAG)
if (BENCHMARK_HAS_FNO_STACK_PROTECTOR_FLAG)
list(APPEND ASM_TEST_FLAGS -fno-stack-protector)
endif()
split_list(ASM_TEST_FLAGS)
string(TOUPPER "${CMAKE_CXX_COMPILER_ID}" ASM_TEST_COMPILER)
macro(add_filecheck_test name)
cmake_parse_arguments(ARG "" "" "CHECK_PREFIXES" ${ARGV})
add_library(${name} OBJECT ${name}.cc)
set_target_properties(${name} PROPERTIES COMPILE_FLAGS "-S ${ASM_TEST_FLAGS}")
set(ASM_OUTPUT_FILE "${CMAKE_CURRENT_BINARY_DIR}/${name}.s")
add_custom_target(copy_${name} ALL
COMMAND ${PROJECT_SOURCE_DIR}/tools/strip_asm.py
$<TARGET_OBJECTS:${name}>
${ASM_OUTPUT_FILE}
BYPRODUCTS ${ASM_OUTPUT_FILE})
add_dependencies(copy_${name} ${name})
if (NOT ARG_CHECK_PREFIXES)
set(ARG_CHECK_PREFIXES "CHECK")
endif()
foreach(prefix ${ARG_CHECK_PREFIXES})
add_test(NAME run_${name}_${prefix}
COMMAND
${LLVM_FILECHECK_EXE} ${name}.cc
--input-file=${ASM_OUTPUT_FILE}
--check-prefixes=CHECK,CHECK-${ASM_TEST_COMPILER}
WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR})
endforeach()
endmacro()