I am trying to get intermediate .i .s file by CMake when compiling .cpp file, but cmake default only output .o file. Is there any command to manipulate cmake to keep these intermediate file, thanks a lot!
If you are using gcc, try adding this line.
SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -save-temps=obj")
Which flag to use depends on the compiler you are using. Also, you should strongly prefer to inject such compiler-and-scenario-specific flags into the build externally, rather than set()-ing them inside the build.
For g++ or clang++, the following invocation would be appropriate:
$ cmake -S . -B build -DCMAKE_BUILD_TYPE=Debug \
-DCMAKE_CXX_FLAGS="-save-temps=obj"
For MSVC it would be:
> cmake -S . -B build "-DCMAKE_CXX_FLAGS=/FA"
I want to integrate clang-tidy to our C and C++, CMake based project which is compiled using a custom GCC toolchain.
I've tried following this tutorial, setting CMAKE_CXX_CLANG_TIDY. I've also tried generating a compilation database by setting CMAKE_EXPORT_COMPILE_COMMANDS to ON and pointing run-clang-tidy.py to its directory.
In both cases, I've encountered (the same) few errors that are probably related to differences between Clang and GCC:
Some warning flags that are enabled in the CMake files are not supported in Clang but are supported in GCC (like -Wlogical-op). As the compiler is GCC, the file builds correctly, and the flag is written to the compilation database, but clang-tidy complains about it.
clang-tidy complains some defines and functions are unavailable, even though the code compiles just fine. As an example, the android-cloexec-open check suggested using O_CLOEXEC to improve security and force the closing of files, but trying to use this define leads to an undefined identifier error (even though our GCC compiles the code).
As an example to a function that is not found, there is clock_gettime.
Our code compiles with the C11 standard and C++14 standard, without GNU extensions:
set(CMAKE_C_STANDARD 11)
set(CMAKE_CXX_STANDARD 14)
set(CMAKE_C_EXTENSIONS OFF)
set(CMAKE_CXX_EXTENSIONS OFF)
The custom toolchain is a cross-compilation toolchain which runs on Linux and compiles to FreeBSD.
Is there a way to disable the passing of some flags by CMake to clang-tidy? Am I using clang-tidy wrong?
I suspect this issue is related to disabling GNU extensions, using a cross-compilation toolchain, and some feature-test-macro which is not defined by default in Clang but is defined with GCC (e.g. _GNU_SOURCE/_POSIX_SOURCE). If this is the case, how can I check it? If not, should I use clang-tidy differently?
EDIT
As #pablo285 asked, here are 2 warnings I get for a single file, and then as I added --warnings-as-errors=*, the build stops:
error: unknown warning option '-Wlogical-op' ; did you mean '-Wlong-long'? [clang-diagnostic-error]
<file path>: error: use of undeclared identifier 'O_CLOEXEC' [clang-diagnostic-error]
O_WRONLY | O_CLOEXEC
^
I decided to write a python script that will replace clang-tidy, receive the commandline from CMake and edit it to fix various errors. Here are the modification to the commandline I tried:
Remove none clang compile flags
This helps with things like the first warning, as now I don't pass flags that clang doesn't know. It seems like I can't configure CMake to pass different set of flags to GCC and to clang-tidy, so if anyone is familiar with some solution to this problem, I'll be happy to hear!
I changed the include directories that are passed to clang-tidy
As mentioned in the post, I use a custom toolchain (which cross-compiles). I used this post and Python to extract the list of standard include directories, and added them to the flag list as a list of -isystem <dir>. I also added -nostdinc so that clang-tidy won't try to look on his own headers instead of mine
This helped with the issue above, as now various defines such as O_CLOEXEC is defined in the toolchain's headers, but as my toolchain is based on GCC, clang couldn't parse the <type_traits> header which includes calls to many compiler intrinsics
I'm not sure what's the best approach in this case
#shycha: Thanks for the tip, I'll try disabling this specific check and I'll edit this post again
Ok, I think that I have a solution. After a couple of evenings I was able to make it work.
In general I compile like this
rm -rf build
mkdir build
cd build
cmake -C ../cmake-scripts/clang-tidy-all.cmake .. && make
Where cmake-scripts directory contains:
clang-tidy-all.cmake
toolchain_arm_clang.cmake
The two important files are listed below.
But what is more important, is how you need to compile this.
First, toolchain_arm_clang.cmake is referenced directly from clang-tidy-all.cmake via set(CMAKE_TOOLCHAIN_FILE ...). It must be, however, referenced from the point of view of the building directory, so if you use multiple levels of build-dirs, e.g.: build/x86, build/arm, build/darwin, etc., then you must modify that path accordingly.
Second, the purpose of set(CONFIG_SCRIPT_PRELOADED ...) is to be sure that the config script was pre-loaded, i.e., cmake -C ../cmake-scripts/clang-tidy-all.cmake ..
Typically, you would want to have something like this somewhere in your CMakeLists.txt file:
message(STATUS "CONFIG_SCRIPT_PRELOADED: ${CONFIG_SCRIPT_PRELOADED}")
if(NOT CONFIG_SCRIPT_PRELOADED)
message(FATAL_ERROR "Run cmake -C /path/to/cmake.script to preload a config script!")
endif()
Third, there is /lib/ld-musl-armhf.so.1 hard-coded in set(CMAKE_LINKER_ARM_COMPAT_STATIC ...); on the development box that I use, it points to /lib/libc.so, so it might by OK to use /lib/libc.sh instead. I've never tried.
Fourth, using set(CMAKE_C_LINK_EXECUTABLE ...) and set(CMAKE_LINKER_ARM_COMPAT_STATIC ...) was because CMake was complaining about some linking problems during checking the compiler, i.e., before even running make.
Fifth, I was only compiling C++ code, so if you need to compile some C, then it might be required to also properly configure set(CMAKE_C_CREATE_SHARED_LIBRARY ...), but I have no idea whether there is such a config option.
General Advice
Do not integrate it immediately. First test some simple CMake project with one library (preferably a C++ one) and make it work, then add the second library, but in C, tweak it again. And only after that incorporate it into the code base.
Toolchain
I used a custom toolchain with GCC 8.3.0 and musl C library, so locations of some files might be different for other toolchains.
Custom CMake
Some variables, like (already mentioned) CONFIG_SCRIPT_PRELOADED, EXPORT_PACKAGE_TO_GLOBAL_REGISTRY, DO_NOT_BUILD_TESTS, or DO_NOT_BUILD_BENCHMARKS are not generic CMake options, i.e., I use them only in my CMakeLists.txt, so you can safely ignore them.
Variables that are unset at the end of each *.cmake file, e.g., build_test, extra_clang_tidy_unchecks_for_tests_only, don't need to be present in the project's main CMakeLists.txt.
Clang
$ clang --version
clang version 10.0.0 (https://github.com/llvm/llvm-project.git 4650b2f36949407ef25686440e3d65ac47709deb)
Target: x86_64-unknown-linux-gnu
Thread model: posix
InstalledDir: /opt/local/bin
Files
clang-tidy-all.cmake:
set(ALL_CXX_WARNING_FLAGS --all-warnings -Weverything -Wno-c++98-compat -Wno-c++98-c++11-compat -Wno-c++98-c++11-c++14-compat -Wno-padded -Wno-c++98-compat-pedantic)
set(CXX_COMPILE_OPTIONS "-std=c++17;-O3;${ALL_CXX_WARNING_FLAGS}" CACHE INTERNAL "description")
set(CMAKE_CROSSCOMPILING True)
set(CMAKE_TOOLCHAIN_FILE "../cmake-scripts/toolchain_arm_clang.cmake" CACHE FILEPATH "CMake toolchain file")
set(CONFIG_SCRIPT_PRELOADED true CACHE BOOL "Ensures that config script was preloaded")
set(build_test False)
if(build_test)
message(STATUS "Using test mode clang-tidy checks!")
set(extra_clang_tidy_unchecks_for_tests_only ",-google-readability-avoid-underscore-in-googletest-name,-cppcoreguidelines-avoid-magic-numbers,-cppcoreguidelines-special-member-functions")
endif()
set(CMAKE_CXX_CLANG_TIDY "clang-tidy;--enable-check-profile;--checks=-*,abseil-string-find-startswith,bugprone-*,cert-*,clang-analyzer-*,cppcoreguidelines-*,google-*,hicpp-*,llvm-*,misc-*,modernize-*,-modernize-use-trailing-return-type,performance-*,readability-*,-readability-static-definition-in-anonymous-namespace,-readability-simplify-boolean-expr,portability-*${extra_clang_tidy_unchecks_for_tests_only}" CACHE INTERNAL "clang-tidy")
message(STATUS "build_test: ${build_test}")
message(STATUS "extra_clang_tidy_unchecks_for_tests_only: ${extra_clang_tidy_unchecks_for_tests_only}")
message(STATUS "CMAKE_CXX_CLANG_TIDY: ${CMAKE_CXX_CLANG_TIDY}")
# We want to skip building tests when clang-tidy is run (it takes too much time and serves nothing)
if(DEFINED CMAKE_CXX_CLANG_TIDY AND NOT build_test)
set(DO_NOT_BUILD_TESTS true CACHE BOOL "Turns OFF building tests")
set(DO_NOT_BUILD_BENCHMARKS true CACHE BOOL "Turns OFF building benchmarks")
endif()
unset(build_test)
unset(extra_clang_tidy_unchecks_for_tests_only)
set(EXPORT_PACKAGE_TO_GLOBAL_REGISTRY "OFF" CACHE INTERNAL "We don't export clang-tidy-all version to global register")
toolchain_arm_clang.cmake:
set(CMAKE_SYSTEM_NAME Linux)
set(CMAKE_SYSTEM_VERSION 4.14.0)
set(CMAKE_SYSTEM_PROCESSOR arm)
set(gcc_version 8.3.0)
set(x_tools "/opt/zynq/xtl")
set(CMAKE_C_COMPILER "clang" CACHE INTERNAL STRING)
set(CMAKE_CXX_COMPILER "clang++" CACHE INTERNAL STRING)
set(CMAKE_RANLIB "llvm-ranlib" CACHE INTERNAL STRING)
set(CMAKE_AR "llvm-ar" CACHE INTERNAL STRING)
set(CMAKE_AS "llvm-as" CACHE INTERNAL STRING)
set(CMAKE_LINKER "ld.lld" CACHE INTERNAL STRING)
execute_process(
COMMAND bash -c "dirname `whereis ${CMAKE_LINKER} | tr -s ' ' '\n' | grep ${CMAKE_LINKER}`"
OUTPUT_VARIABLE cmake_linker_dir
)
string(REGEX REPLACE "\n$" "" cmake_linker_dir "${cmake_linker_dir}")
set(cmake_linker_with_dir "${cmake_linker_dir}/${CMAKE_LINKER}" CACHE INTERNAL STRING)
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -iwithsysroot /include/c++/${gcc_version} -iwithsysroot /include/c++/${gcc_version}/arm-linux-musleabihf" CACHE INTERNAL STRING)
set(CMAKE_SYSROOT ${x_tools}/arm-linux-musleabihf)
set(CMAKE_FIND_ROOT_PATH ${x_tools}/arm-linux-musleabihf)
set(CMAKE_INSTALL_PREFIX ${x_tools}/arm-linux-musleabihf)
set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY BOTH)
set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE BOTH)
set(CMAKE_FIND_ROOT_PATH_MODE_PACKAGE NEVER)
set(triple arm-linux-musleabihf)
set(CMAKE_LIBRARY_ARCHITECTURE ${triple})
set(CMAKE_C_COMPILER_TARGET ${triple})
set(CMAKE_CXX_COMPILER_TARGET ${triple})
set(lib_path_arm ${x_tools}/arm-linux-musleabihf/lib)
## Bootstrap library stuff:
set(Scrt1_o ${lib_path_arm}/Scrt1.o)
set(crti_o ${lib_path_arm}/crti.o)
set(crtn_o ${lib_path_arm}/crtn.o)
set(lib_path_gcc ${x_tools}/lib/gcc/${triple}/${gcc_version})
set(crtbeginS_o ${lib_path_gcc}/crtbeginS.o)
set(crtendS_o ${lib_path_gcc}/crtendS.o)
# Clang as linker
# --no-pie disable position independent executable, which is required when building
# statically linked executables.
set(CMAKE_CXX_LINK_EXECUTABLE "clang++ --target=${triple} -Wl,--no-pie --sysroot=${CMAKE_SYSROOT} ${CMAKE_CXX_FLAGS} -fuse-ld=${cmake_linker_with_dir} <CMAKE_CXX_LINK_FLAGS> <LINK_FLAGS> <LINK_LIBRARIES> <OBJECTS> -o <TARGET> ")
set(CMAKE_CXX_CREATE_SHARED_LIBRARY "clang++ -Wl, --target=${triple} --sysroot=${CMAKE_SYSROOT} ${CMAKE_CXX_FLAGS} -fuse-ld=${cmake_linker_with_dir} -shared <CMAKE_CXX_LINK_FLAGS> <LINK_FLAGS> <LINK_LIBRARIES> <OBJECTS> -o <TARGET> ")
#
# Do not use CMAKE_CXX_CREATE_STATIC_LIBRARY -- it is created automatically
# by cmake using ar and ranlib
#
#set(CMAKE_CXX_CREATE_STATIC_LIBRARY "clang++ -Wl,--no-pie,--no-export-dynamic,-v -v --target=${triple} --sysroot=${CMAKE_SYSROOT} ${CMAKE_CXX_FLAGS} -fuse-ld=ld.lld <CMAKE_CXX_LINK_FLAGS> <LINK_FLAGS> <LINK_LIBRARIES> <OBJECTS> -o <TARGET> ")
## Linker as linker
set(CMAKE_LINKER_ARM_COMPAT_STATIC "-pie -EL -z relro -X --hash-style=gnu --eh-frame-hdr -m armelf_linux_eabi -dynamic-linker /lib/ld-musl-armhf.so.1 ${Scrt1_o} ${crti_o} ${crtbeginS_o} -lstdc++ -lm -lgcc_s -lgcc -lc ${crtendS_o} ${crtn_o}")
set(CMAKE_C_LINK_EXECUTABLE "${CMAKE_LINKER} ${CMAKE_LINKER_ARM_COMPAT_STATIC} <CMAKE_C_LINK_FLAGS> <LINK_FLAGS> <LINK_LIBRARIES> <OBJECTS> -o <TARGET>")
# Debian bug 708744(?)
#include_directories("${CMAKE_SYSROOT}/usr/include/")
#include_directories("${CMAKE_SYSROOT}/usr/include/c++/${gcc_version}")
#include_directories("${CMAKE_SYSROOT}/usr/include/c++/${gcc_version}/${triple}")
## Clang workarounds:
set(toolchain_lib_dir_0 "${CMAKE_SYSROOT}/lib")
set(toolchain_lib_dir_1 "${CMAKE_SYSROOT}/../lib")
set(toolchain_lib_dir_2 "${CMAKE_SYSROOT}/../lib/gcc/${triple}/${gcc_version}")
set(CMAKE_TOOLCHAIN_LINK_FLAGS "-L${toolchain_lib_dir_0} -L${toolchain_lib_dir_1} -L${toolchain_lib_dir_2}")
## CMake workarounds
set(CMAKE_EXE_LINKER_FLAGS ${CMAKE_TOOLCHAIN_LINK_FLAGS} CACHE INTERNAL "exe link flags")
set(CMAKE_MODULE_LINKER_FLAGS ${CMAKE_TOOLCHAIN_LINK_FLAGS} CACHE INTERNAL "module link flags")
set(CMAKE_SHARED_LINKER_FLAGS ${CMAKE_TOOLCHAIN_LINK_FLAGS} CACHE INTERNAL "shared link flags")
unset(cmake_linker_with_dir)
unset(cmake_linker_dir)
Maybe not exactly what you're looking for but I'm using this in CMakeLists.txt:
set(CMAKE_EXPORT_COMPILE_COMMANDS ON)
add_custom_target(lint
COMMAND sh -c "run-clang-tidy -header-filter=.* -checks=`tr '\\n' , <${CMAKE_SOURCE_DIR}/checks.txt` >lint.out 2>lint.err"
COMMAND sh -c "grep warning: lint.out || true"
COMMAND ls -lh ${CMAKE_BINARY_DIR}/lint.out
VERBATIM
WORKING_DIRECTORY ${CMAKE_BINARY_DIR}
)
This creates a separate build target (make lint) for the clang-tidy check. clang-tidy takes a long time for my project so I don't want to run it during every build; make lint can be run manually if required, and it's also executed in a CI job after every push to the repo (in a way that makes the CI pipeline fail, blocking the merge, if there are any findings).
The output of make lint is the list of clang-tidy findings with as little context as possible. The full output, including context for findings, is in lint.out, and error messages are in lint.err, both of which I'm saving as CI artefacts.
checks.txt is a text file in the project root that defines which clang-tidy checks to activate, like so:
*
-altera-id-dependent-backward-branch
-altera-struct-pack-align
-altera-unroll-loops
-android-*
The first line enables all available checks, the other lines disable checks that I don't want.
Will only work in a Unix-like system of course.
My goal is to add my Qt project to a Jenkins buildserver, for nightly builds. Therefore I want to compile my project from the command line. I copied the buildsteps located in the build configuration:
"/opt/fslc-x11/2.5/sysroots/x86_64-fslcsdk-linux/usr/bin/qt5/qmake" "/home/xxxx/repositories/xxx/xxx.pro" -spec linux-oe-g++ && /usr/bin/make qmake_all
"/usr/bin/make"
I execute these commands in the build directory. The problem lies in the qmake command. The qmake command generates the makefile, but this makefile is different when I generate it in the command line instead of in QtCreator. The binary result after make is ofcourse very different.
It seems that the qmake command from the command line creates a debug makefile instead of a release makefile:
CFLAGS = -pipe -02 -pipe -g -feliminate-unused-debug-types --sysroot=.........
The -02 -pipe -g -feliminate-unused-debug-types part is the only thing added when I run qmake in the command line (checked with diff).
I've tried the following:
Added CONFIG+=release to the qmake command
Added CONFIG-=DEBUG to the qmake command
Furthermore I've verified that the system environment and the terminal emulator is the same.
My question comes down to:
Why does qmake add the (debug) flags when running from the command line?
Does QtCreator add more to the environment that I might have missed?
Let me know if you need more information about the settings or the makefile that is generated.
Ok. So long story short: I've tried compiling for the local Linux distro with the standard qmake and my problem was solved.
It seems that problem lies at the custom qmake of the target (x86_64-fslcsdk-linux). I'm not gonna put more time in this issue, so feel free to add a more satisfying answer. I'll be happy to try it out :).
I'm trying to build a NaCl extension on 64-bit Windows 8.1 using CMake. The same code works on Ubuntu without any problems. Everything goes well until CMake tries to link with this command:
cmake -E cmake_link_script link.txt
CMake: Error running link command: %1 is not a valid Win32 application
The link.txt is as follows:
C:/nacl_sdk/pepper_39/toolchain/win_pnacl/bin/pnacl-ar cr libfoo.a CMakeFiles/foo.dir/Foo.cc.o
C:/nacl_sdk/pepper_39/toolchain/win_pnacl/bin/pnacl-ranlib libfoo.a
This happens with both NMake and Unix makefile generators (the NaCl SDK contains make.exe for Windows).
If I run those commands manually, they succeed. What could be wrong here?
Just like eugensk00 suggested adding ".bat" in toolchain definitions seems to work. It is required to add both for ar and ranlib though:
set(CMAKE_AR "${PLATFORM_PREFIX}/bin/pnacl-ar.bat" CACHE STRING "")
set(CMAKE_RANLIB "${PLATFORM_PREFIX}/bin/pnacl-ranlib.bat" CACHE STRING "")
My project is build using CMake and is compiled with DistCC + GCC.
I configure the compiler as follows:
SET(CMAKE_C_COMPILER "distcc variation-of-gcc")
To build the project, I simply run 'cmake' and then 'make -jXX'.
Although distcc really speeds up things, I sometimes want to build without distribution - I want it to build locally on the machine.
I know I can modify DISTCC_HOSTS to include only localhost - but this still has the overhead of distcc networking, although it is faster than the overhead for other machines...
I can also do that by rerunning cmake again and modifying the CMAKE_C_COMPILER using customization flags.
But I am looking for a way to do that by just adding a flag directly to 'make'.
I.e.
# This will use distcc:
make -jXX ...
# This will run locally:
make LOCAL_BUILD=1 -jX ...
Is there a CMake trick I can use?
We use the following to allow make time (rather than cmake time) switching on and off of the -Werror flag.
if(CMAKE_GENERATOR STREQUAL "Unix Makefiles")
# TODO: this approach for the WERROR only works with makefiles not Ninja
set(CMAKE_CXX_COMPILE_OBJECT "<CMAKE_CXX_COMPILER> <DEFINES> <INCLUDES> <FLAGS> $(WERROR) -o <OBJECT> -c <SOURCE>")
endif()
Then we run
make WERROR=-Werror
to turn on warnings as error.
I expect you could do something similar to have whether to use distcc come from a make variable. Like this:
set(CMAKE_CXX_COMPILE_OBJECT "$(USE_DISTCC) <CMAKE_CXX_COMPILER> <DEFINES> <INCLUDES> <FLAGS> -o <OBJECT> -c <SOURCE>")
And then run either
make USE_DISTCC=distcc
or just
make
The simplest thing to do (IMO) is write a little script in your project that invokes the compiler, and change your CMake files to run that script instead of containing the name of the compiler directly:
SET(CMAKE_C_COMPILER "my-gcc-script")
Now you can have that script normally run distcc, but (based on an environment variable or something) also run without distcc. There isn't any need to change anything in your CMake files.