https://github.com/google/benchmark/pull/801 is stuck with some cryptic cmake failure due to
some linking issue between googletest and threading libraries.
I suspect that is mostly happening because of the, uhm,
intentionally extremely twisted-in-the-brains approach that is being used to
actually build the library as part of the buiild,
except without actually building it as part of the build.
If we do actually build it as part of the build,
then all the transitive dependencies should magically be in order,
and maybe everything will just work.
This new version of cmake magic was written by me in
0e22f085c5/cmake/Modules/GoogleTest.cmake.in0e22f085c5/cmake/Modules/GoogleTest.cmake, based on the official googletest docs and LOTS of experimentation.
Summary:
- When google benchmark is used as a submodule in a parent projects
whose min CMake version is 3.3.2 or later, the google benchmark
`CMakeLists.txt` triggers a warning regarding CMake policy 0063:
```
CMake Warning (dev) at tests/googlebenchmark/src/CMakeLists.txt:19 (add_library):
Policy CMP0063 is not set: Honor visibility properties for all target
types. Run "cmake --help-policy CMP0063" for policy details. Use the
cmake_policy command to set the policy and suppress this warning.
Target "benchmark" of type "STATIC_LIBRARY" has the following visibility
properties set for CXX:
CXX_VISIBILITY_PRESET
VISIBILITY_INLINES_HIDDEN
For compatibility CMake is not honoring them for this target.
This warning is for project developers. Use -Wno-dev to suppress it.
```
- Set CMake Policy 0063 to NEW if the policy is available. This will not
affect parent projects who include benchmark but do not have a CMake min
version of 3.3.2 or later, i.e. when this policy is introduced.
If this policy isn't set, CMake emits a large warning when project() is
called from a cmake subdirectory.
This came up when the benchmark library was added to the LLVM build, and
it was reported in https://llvm.org/PR38874. This patch was the fix I
applied locally to fix the issue, and I wanted to send it upstream.
For several versions now, CMake by default refers to macOS’ Clang as AppleClang instead of just Clang, which would fail STREQUAL. Fixed by changing it to MATCHES.
`MSVC` is true for clang-cl, but `"${CMAKE_CXX_COMPILER_ID}" STREQUAL
"MSVC"` is false, so we would enable -Wall, which means -Weverything
with clang-cl, and we get tons of undesired warnings.
Use the simpler condition to fix things.
Patch by: Reid Kleckner @rnk
* Set -Wno-deprecated-declarations for Intel
Intel compiler silently ignores -Wno-deprecated-declarations
so warning no. 1786 must be explicitly suppressed.
* Make std::int64_t → double casts explicit
While std::int64_t → double is a perfectly conformant
implicit conversion, Intel compiler warns about it.
Make them explicit via static_cast<double>.
* Make std::int64_t → int casts explicit
Intel compiler warns about emplacing an std::int64_t
into an int container. Just make the conversion explicit
via static_cast<int>.
* Cleanup Intel -Wno-deprecated-declarations workaround logic
As @dominichamon and I have discussed, the current reporter interface
is poor at best. And something should be done to fix it.
I strongly suspect such a fix will require an entire reimagining
of the API, and therefore breaking backwards compatibility fully.
For that reason we should start deprecating and removing parts
that we don't intend to replace. One of these parts, I argue,
is the CSVReporter. I propose that the new reporter interface
should choose a single output format (JSON) and traffic entirely
in that. If somebody really wanted to replace the functionality
of the CSVReporter they would do so as an external tool which
transforms the JSON.
For these reasons I propose deprecating the CSVReporter.
* 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
This patch disables the -Winvalid-offsetof warning for GCC and Clang
when using it to check the cache lines of the State object.
Technically this usage of offsetof is undefined behavior until C++17.
However, all major compilers support this application as an extension,
as demonstrated by the passing static assert (If a compiler encounters UB
during evaluation of a constant expression, that UB must be diagnosed).
Unfortunately, Clang and GCC also produce a warning about it.
This patch temporarily suppresses the warning using #pragma's in the
source file (instead of globally suppressing the warning in the build systems).
This way the warning is ignored for both CMake and Bazel builds without
having to modify either build system.
* Improve State packing: put important members on first cache line.
This patch does a few different things to ensure commonly accessed
data is on the first cache line of the `State` object.
First, it moves the `error_occurred_` member to reside after
the `started_` and `finished_` bools, since there was internal
padding there that was unused.
Second, it moves `batch_leftover_` and `max_iterations` further up
in the struct declaration. These variables are used in the calculation
of `iterations()` which users might call within the loop. Therefore
it's more important they exist on the first cache line.
Finally, this patch turns the bool members into bitfields. Although
this shouldn't have much of an effect currently, because padding is
still needed between the last bool and the first size_t, it should
help in future changes that require more "bool like" members.
* Remove bitfield change for now
* Move bools (and their padding) to end of "first cache line" vars.
I think it makes the most sense to move the padding required
following the group of bools to the end of the variables we want
on the first cache line.
This also means that the `total_iterations_` variable, which is the
most accessed, has the same address as the State object.
* Fix static assertion after moving bools
* Add support for GTest based unit tests.
As Dominic and I have previously discussed, there is some
need/desire to improve the testing situation in Google Benchmark.
One step to fixing this problem is to make it easier to write
unit tests by adding support for GTest, which is what this patch does.
By default it looks for an installed version of GTest. However the
user can specify -DBENCHMARK_BUILD_EXTERNAL_GTEST=ON to instead
download, build, and use copy of gtest from source. This is
quite useful when Benchmark is being built in non-standard configurations,
such as against libc++ or in 32 bit mode.
* Add BENCHMARK_BUILD_32_BITS option and add builders to test it
* Attempt to fix travis configuration
* Make add_required_cxx_compiler_flag cause an error when the flag isn't supported
* add gcc-multilib dependancy on travis
* attempt to fix travis.yml parsing error
* Require g++-multilib instead of gcc-multilib
* Add 32 bit release configurations
* Attempt to fix libc++ travis build w/ 32 bits
* Work around CMake configuration failure on Travis
fixes#354
The build fails with ICC17 because of warnings and Werror. What is the correct solution to fix it?
Should a patch
disable Werror for ICC (or maybe all non known compilers)
disable the false postive warnings for all files. This could be done using:
add_cxx_compiler_flag(-wd2102) #ICC17u2: Many false positives for Wstrict-aliasing
add_cxx_compiler_flag(-wd2259) #ICC17u2: non-pointer conversion from "long" to "int" may lose significant bits (even for explicit static cast, sleep.cc(44))
add_cxx_compiler_flag(-wd654) #ICC17u2: overloaded virtual function "benchmark::Fixture::SetUp" is only partially overridden (because of deprecated overload)
disable warnings at file level or some other granularity
* Refactor benchmark.cc into benchmark_register.cc and benchmark_run.cc
The benchmark.cc file is getting really big and it contains a bunch of
unrelated components. This patch separates the files into two separate
parts. The "runtime" parts and the "registration" parts.
This patch also removes the PIMPL used by Benchmark. Previously we couldn't
have STL types in the interface but now we can. Therefore there is no reason
to keep BenchmarkImp.
* add missing include
* rework windows timers again
* Guard timespec on older Windows versions
* Remove old thread safety annotation workarounds
* Change to using per-thread timers
* fix bad assertions
* fix copy paste error on windows
* Fix thread safety annotations
* Make null-log thread safe
* remove remaining globals
* use chrono for walltime since it is thread safe
* consolidate timer functions
* Add missing ctime include
* Rename to be consistent with Google style
* Format patch using clang-format
* cleanup -Wthread-safety configuration
* Don't trust _POSIX_FEATURE macros because OS X lies.
* Fix OS X thread timings
* attempt to fix mingw build
* Attempt to make mingw work again
* Revert old mingw workaround
* improve diagnostics
* Drastically improve OS X measurements
* Use average real time instead of max
Add policy CMP0056, which honors the link flags in try_compile and
try_run. This allows for building against non-system libc++ by providing
the correct -L and rpath options in a containing project.
For example:
set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -L ${LLVM_ROOT}/lib -l c++ -l c++abi")
set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -Wl,-rpath,${LLVM_ROOT}/lib")
In addition to release, CMake supports RELWITHDEBINFO and MINSIZEREL
build configurations. In particular, debug info is necessary for many
profilers to do anything useful, making RELWITHDEBINFO important here.
MINSIZEREL was added for completeness' sake.
BENCHMARK_ENABLE_LTO=true was completely replacing
CMAKE_CXX_FLAGS_RELEASE; meaning neither CMake's release defaults nor
user customizations were being applied.
This change looks for CMake's default setting for MSVC++, /W3 (and any
other level should that change in the future), and removes it before
adding /W4. This stops the build for MSVC++ emitting warnings about
/W4 overriding /W3 earlier on the command line.
This also points out some important issues like:
warning: conversion to 'size_t {aka unsigned int}' from 'long long int' may alter its value [-Wconversion]
state.SetBytesProcessed(items_processed * sizeof(v));
This occurs on 32 bit systems where size_t is only 32 bits.
This patch adds a `coverage` target that allows coverage statisitics to be
retrieved for the project. It requires that lcov and gcov is installed and
that the generator is unix makefiles but this can be improved upon in
future releases.
To make it work use the coverage build type:
```
cmake -DCMAKE_BUILD_TYPE=Coverage .
make coverage
```
This improves development iterations when working in debug mode as you
don't have to fix up warnings to get the code to compile. Once a feature
is complete you can then run a release build and fix up all the warnings.
