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benchmark/test/AssemblyTests.cmake

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CMake
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Fix DoNotOptimize() GCC copy overhead (#1340) (#1410) * Fix DoNotOptimize() GCC copy overhead (#1340) The issue is that GCC DoNotOptimize() does a full copy of an argument if it's not a pointer and it slows down a benchmark. If an argument is big enough there is a memcpy() call for copying the argument. An argument object can be a big object so DoNotOptimize() could add sufficient overhead and affects benchmark results. The cause is in GCC behavior with asm volatile constraints. Looks like GCC trying to use r(register) constraint for all cases despite object size. See: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105519 The solution is the split DoNotOptimize() in two cases - value fits in register and value doesn't fit in register. And use case specific asm constraint. std::is_trivially_copyable trait is needed because "+r" constraint doesn't work with non trivial copyable objects. - Fix requires support C++11 feature std::is_trivially_copyable from GCC compiler. The feature has been supported since GCC 5 - Fallback for GCC version < 5 still exists but it uses "m" constraint which means a little bit more overhead in some cases - Add assembly tests for issued cases Fixes #1340 * Add supported compiler versions info for assembly tests - Assembly tests are inherently non-portable. So explicitly add GCC and Clang versions required for reliable tests passed - Write a warning message if the current compiler version isn't supported
2022-06-20 09:12:58 +00:00
set(CLANG_SUPPORTED_VERSION "5.0.0")
set(GCC_SUPPORTED_VERSION "5.5.0")
if (CMAKE_CXX_COMPILER_ID MATCHES "Clang")
if (NOT CMAKE_CXX_COMPILER_VERSION VERSION_EQUAL ${CLANG_SUPPORTED_VERSION})
message (WARNING
"Unsupported Clang version " ${CMAKE_CXX_COMPILER_VERSION}
". Expected is " ${CLANG_SUPPORTED_VERSION}
". Assembly tests may be broken.")
endif()
elseif(CMAKE_CXX_COMPILER_ID MATCHES "GNU")
if (NOT CMAKE_CXX_COMPILER_VERSION VERSION_EQUAL ${GCC_SUPPORTED_VERSION})
message (WARNING
"Unsupported GCC version " ${CMAKE_CXX_COMPILER_VERSION}
". Expected is " ${GCC_SUPPORTED_VERSION}
". Assembly tests may be broken.")
endif()
else()
message (WARNING "Unsupported compiler. Assembly tests may be broken.")
endif()
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 22:10:47 +00:00
split_list is not defined for assembly tests (#595) * Update AUTHORS and CONTRIBUTORS * split_list is not defined for assembly tests
2018-05-14 14:02:49 +00:00
include(split_list)
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 22:10:47 +00:00
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 ${name}.cc)
annotate and export public symbols (#1321)
2022-02-14 10:48:53 +00:00
target_link_libraries(${name} PRIVATE benchmark::benchmark)
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 22:10:47 +00:00
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
Partially revert "Do not depend on unversioned python binary (#1496)" (#1501) As predicted, the cmake part of the change is contentious. https://github.com/google/benchmark/pull/1496#issuecomment-1276508266 This partially reverts commit 229bc5a93729d72b97a77759b2ba991008c4e330.
2022-10-13 09:03:29 +00:00
COMMAND ${PROJECT_SOURCE_DIR}/tools/strip_asm.py
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 22:10:47 +00:00
$<TARGET_OBJECTS:${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()