Very long repeated compile time for building LLVM from sources - cmake

Steps for reproduce:
Build LLVM from sources.
Change something in one cpp file.
Build LLVM again. Not a long compile time for that case because I've changed only one cpp file, that's ok.
But if I reboot computer after changing cpp file or wait some long time and try to build LLVM after that again, compile time will be very long, like in first step. But I've changed only one cpp file. Why it's happens and how can I avoid this?
Cmake command:
cmake -G Ninja ../llvm \
-DCMAKE_BUILD_TYPE=RelWithDebInfo \
-DLLVM_TARGETS_TO_BUILD=X86 \
-DLLVM_ENABLE_PROJECTS=clang \
Ninja command:
ninja -j 4 -l 1

Related

How to run sanitizers on whole project

I'm trying to get familiar with sanitizers as ASAN, LSAN etc and got a lot of useful information already from here: https://developers.redhat.com/blog/2021/05/05/memory-error-checking-in-c-and-c-comparing-sanitizers-and-valgrind
I am able to run all sort of sanitizers on specific files, as shown on the site, like this:
clang -g -fsanitize=address -fno-omit-frame-pointer -g ../TestFiles/ASAN_TestFile.c
ASAN_SYMBOLIZER_PATH=/usr/local/bin/llvm-symbolizer ./a.out >../Logs/ASAN_C.log 2>&1
which generates a log with found issue. Now I would like to extend this to run upon building the project with cmake. This is the command to build it at the moment:
cmake -S . -B build
cd build
make
Is there any way I can use this script with adding the sanitizers, without having to alter the cmakelist.txt file??
For instance something like this:
cmake -S . -B build
cd build
make -fsanitize=address
./a.out >../Logs/ASAN_C.log 2>&1
The reason is that I want to be able to build the project multiple times with different sanitizers (since they cannot be used together) and have a log created without altering the cmakelist.txt file (just want to be able to quickly test the whole project for memory issues instead of doing it for each file created).
You can add additional compiler flags from command line during the build configuration:
cmake -D CMAKE_CXX_FLAGS="-fsanitize=address" -D CMAKE_C_FLAGS="-fsanitize=address" /path/to/CMakeLists.txt
If your CMakeLists.txt is configured properly above should work. If that does not work then try adding flags as environment variable:
cmake -E env CXXFLAGS="-fsanitize=address" CFLAGS="-fsanitize=address" cmake /path/to/CMakeLists.txt

CMake + Ninja : how to implement incremental compilation under the path of different source directories

Every time I get a different source directory, and I have a fixed build directory. Every time I will run cmake /path/to/project and run ninja. It will report an error : Make Error: The source "/path1/to/project/CMakeLists.txt" does not match the source "/path2/to/project/CMakeLists.txt" used to generate cache. Re-run cmake with a different source directory.
So what I did was manually change the options related to the path of project in the CMakeCache.txt. The result is that it will compile the project from scratch every time instead of incrementally compiling, So is there any feasible way to achieve incremental compilation or in this case it is impossible to achieve incremental compilation ?
Mount the source directory always to a same constant absolute location. On Linux, you could use mount namespaces, for example use proot.
proot -b /path/to/project:/work -w /work cmake -B builddir -S .
proot -b /path/to/project:/work -w /work cmake --build builddir

CMake incremental compilation through toolchain upgrade

I am trying to find a way to enable incremental compilation with CMake through a toolchain upgrade. Here is the problematic scenario :
Branch main uses g++-9 (using CMAKE_CXX_COMPILER=g++-9)
A new branch uses g++-10 (using CMAKE_CXX_COMPILER=g++-10)
Commits are happening on both branches
Incremental builds on one branch work fine
Switching to the other branch and explicitly invoking CMake fails
My question is the following : I'm looking for the proper way to make the invocation of CMake succeed and rebuild all the project from scratch when a toolchain change happens.
Here is a script that will make it quick and easy to reproduce the problem. This script requires Docker. It will create folders Sources and Build at the location where it is executed to avoid littering your filesystem. It then creates Dockerfiles to build docker containers with both g++ and cmake. It then creates a dummy Hello World C++ CMake project. Finally, it creates a folder for build artifacts and then executes the build with g++-9 and then g++-10. The second build fails because CMake generates an error.
#!/bin/bash
set -e
mkdir -p Sources
mkdir -p Build
# Creates a script that will be executed inside the docker container to perform builds
cat << EOF > Sources/Compile.sh
cd /Build \
&& cmake /Sources \
&& make \
&& ./IncrementalBuild
EOF
# Creates a Dockerfile that will be used to have both gcc-9 and cmake
cat << EOF > Sources/Dockerfile-gcc9
FROM gcc:9
RUN apt-get update && apt-get install -y cmake
RUN ln -s /usr/local/bin/g++ /usr/local/bin/g++-9
ADD Compile.sh /Compile.sh
RUN chmod +x /Compile.sh
ENTRYPOINT /Compile.sh
EOF
# Creates a Dockerfile that will be used to have both gcc-10 and cmake
cat << EOF > Sources/Dockerfile-gcc10
FROM gcc:10
RUN apt-get update && apt-get install -y cmake
RUN ln -s /usr/local/bin/g++ /usr/local/bin/g++-10
ADD Compile.sh /Compile.sh
RUN chmod +x /Compile.sh
ENTRYPOINT /Compile.sh
EOF
# Creates a dummy C++ program that will be compiled
cat << EOF > Sources/main.cpp
#include <iostream>
int main()
{
std::cout << "Hello World!\n";
}
EOF
# Creates CMakeLists.txt that will be used to compile the dummy C++ program
cat << EOF > Sources/CMakeLists.txt
cmake_minimum_required(VERSION 3.9)
project(IncrementalBuild CXX)
add_executable(IncrementalBuild main.cpp)
set_target_properties(IncrementalBuild PROPERTIES CXX_STANDARD 17)
EOF
# Build the docker images with both Dockerfiles created earlier
docker build -t cmake-gcc:9 -f Sources/Dockerfile-gcc9 Sources
docker build -t cmake-gcc:10 -f Sources/Dockerfile-gcc10 Sources
# Run a build with g++-9
echo ""
echo "### Compiling with g++-9 and then running the result..."
docker run --rm --user $(id -u):$(id -g) -v $(pwd)/Sources:/Sources -v $(pwd)/Build:/Build -e CXX=g++-9 cmake-gcc:9
echo ""
# Run a build with g++-10
echo "### Compiling with g++-10 and then running the result..."
docker run --rm --user $(id -u):$(id -g) -v $(pwd)/Sources:/Sources -v $(pwd)/Build:/Build -e CXX=g++-10 cmake-gcc:10
echo ""
# Print success if we reach this point
echo "SUCCESS!"
I'm looking for the proper way to make the invocation of CMake succeed and rebuild all the project from scratch when a toolchain change happens.
The proper way is to use a fresh binary directory. Either remove the binary directory when changing and let it recreate or just use a separate different directory for each toolchain.
Use Build/gcc10 binary directory for gcc10 build and Build/gcc9 for gcc9 builds.
No need to cd Build and mkdir with nowadays cmake - use cmake -S. -BBuild. Also do not use make - prefer cmake --build Build to let you switch generator later.
"If you change the toolchain, you should start with a fresh build. There are too many things that assume the toolchain doesn’t change and while you may be able to find workarounds which appear to work, I recommend you always use a fresh build tree for a different toolchain. This same logic also applies if you update the existing toolchain in-place (e.g. you update to a newer version of GCC on Linux, a newer version of Xcode on macOS, etc.). CMake queries compiler capabilities and caches the results. If you change the toolchain in a way that CMake can’t catch, then you end up with stale cached capabilities being used for the new/updated toolchain. Please don’t do that." - Craig Scott
So essentially I don't think it's possible. You just need to blow away your build. The best thing you can do is alert users if CMake isn't doing it for you.
Perhaps reply on this also:
https://discourse.cmake.org/t/how-to-change-toolchain-without-breaking-developer-workflows/1166
Or start another discourse.

How to restrict cmake commands based on which target is built

I have a cmake project which produces several executables. I want to package each executable in seperate Docker containers, so inside the Dockefile, I only built the target that I need:
RUN mkdir build \
&& cd build \
&& cmake /app/project -DCMAKE_BUILD_TYPE=Release
&& make -j 2 myExecutable \
&& make install/fast
This works as expected, but I run into an issue with the conan cmake integration. The installation is done when cmake is called, not during the actual build - this means that no matter which target I want to actually build, all the conan installation calls present in my cmake files are called - so way more packages are installed than necessary.
# for every target
# include conan dependencies (each target has its own conanfile.txt)
conan_cmake_run(CONANFILE conanfile.txt
BASIC_SETUP CMAKE_TARGETS
BUILD_TYPE "${CMAKE_BUILD_TYPE}"
BUILD outdated
${update_conan}
)
conan_target_link_libraries(${PROJECT_NAME})
Is there a way to make the cmake calls dependend on which target I actually want to build?
Unfortunately not, the macro conan_cmake_run has no distinction about which target is involved or even it was executed before. You could use CMake options to run or not conan_cmake_run.
Also, you could comment/vote your request thorough the issue https://github.com/conan-io/cmake-conan/issues/105
Regards!

Use Fortify sourceanalyzer with CMake

I have a Makefile generated by CMake. The following path to CMake executable is set in the Makefile:
CMAKE_COMMAND = /home/xyz/opt/cmake/cmake-3.1.1/bin/cmake
How can I integrate Fortify sourceanalyzer with it and run scans?
I had the same challenge but solved it by running it like this:
sourceanalyzer -b project_ID -clean
Go to your build directory and perform make clean or remove all contents including the Makefile
Run cmake by changing CC and CXX variables:
CC="sourceanalyzer -b project_ID gcc" CXX="sourceanalyzer -b project_ID g++" cmake ..
Run make and fortify should be translating files while compilers do their job.
Run sourceanalyzer -b project_ID -scan -f results.fpr
Hope it helps.
I was tasked with integrating our CMake build system with HP Fortify SCA and came across this Thread that gave some insights but lacked specifics as related to HP Fortify so I thought I would share my implementation.
I created a fortify_tools directory at the same level as the source directory. Inside the fortify_tools are a toolchain file and fortify_cc, fortify_cxx, and fortify_ar scripts that will be set as the cmake_compilers via the toolchain file.
fortify_cc
#!/bin/bash
sourceanalyzer -b <PROJECT_ID> gcc $#
fortify_cxx
#!/bin/bash
sourceanalyzer -b <PROJECT_ID> g++ $#
fortify_ar
#!/bin/bash
sourceanalyzer -b <PROJECT_ID> ar $#
NOTE: insert your project name in place of PROJECT_ID
Setting cmake to use the scripts is accomplished in a toolchain file.
fortify_linux_toolchain.cmake
INCLUDE (CMakeForceCompiler)
SET(CMAKE_SYSTEM_NAME Linux)
SET(CMAKE_SYSTEM_VERSION 1)
#specify the compilers
SET(CMAKE_C_COMPILER ${CMAKE_SOURCE_DIR}/fortify_tools/fortify_cc)
SET(CMAKE_CXX_COMPILER ${CMAKE_SOURCE_DIR}/fortify_tools/fortify_cxx)
SET(CMAKE_AR_COMPILER ${CMAKE_SOURCE_DIR}/fortify_tools/fortify_ar)
To generate makefiles using the toolchain file
ccmake -DCMAKE_TOOLCHAIN_FILE=../fortify_tools/foritfy_linux_toolchain.cmake ../
configure and generate your makefiles and build your project.
Once the project is built from within the build directory generate a fortify report by
sourceanalyzer -Xmx2400M -debug -verbose -b <PROJECT_ID> -scan -f <PROJECT_ID>.fpr
I understand the last step is outside of CMake but I am pretty confident a cmake_custom_command can be created to perform the scan step as a post build action.
Finally, this is just the linux implementation but the concept scales well to Windows by creating the necessary batch files and windows specific toolchain file
Fortify doesn't support CMake, I received confirmation from Fortify support team.
This answer is late, but might help someone. This is actually easy to fix - you simply need to run cmake inside sourceanalyzer as well. Make a simple build script that calls cmake and then make, and use sourceanalyzer on that instead. I am using fortify 4.21.
Our old Fortify script for building hand-created Makefiles used a build command that looked like this:
$SOURCEANALYZER $MEMORY $LAUNCHERSWITCHES -b $BUILDID make -f Makefile -j12
I was able to get it working for a project that had been converted to CMake by replacing the above line with this, inspired by a couple of the other answers here:
CC="$SOURCEANALYZER $MEMORY $LAUNCHERSWITCHES -b $BUILDID gcc" \
CXX="$SOURCEANALYZER $MEMORY $LAUNCHERSWITCHES -b $BUILDID g++" \
AR="$SOURCEANALYZER $MEMORY $LAUNCHERSWITCHES -b $BUILDID ar" \
cmake -G "Unix Makefiles" -DCMAKE_BUILD_TYPE=Debug ..
make -f Makefile -j12 VERBOSE=1
This is with cmake 2.8.12.2 on Linux.
Below is the script i use for my example project to generate HP Fortify report for Android JNI C/C++ Code.
#!/bin/sh
# Configure NDK version and CMake version
NDK_VERSION=21.0.6113669
CMAKE_VERSION=3.10.2
CMAKE_VERSION_PATH=$CMAKE_VERSION.4988404
PROJECTID="JNI_EXAMPLE"
REPORT_NAME=$PROJECTID"_$(date +'%Y%m%d_%H:%M:%S')"
WORKING_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
BUILD_HOME=${WORKING_DIR}/../hpfortify_build
FPR="$BUILD_HOME/$REPORT_NAME.fpr"
# Following exports need to be configured according to host machine.
export ANDROID_SDK_HOME=/Library/Android/sdk
export ANDROID_CMAKE_HOME=$ANDROID_SDK_HOME/cmake/$CMAKE_VERSION_PATH/bin
export ANDROID_NDK_HOME=$ANDROID_SDK_HOME/ndk/$NDK_VERSION
# E.g. JniExample/app/hpfortify/build/CMakeFiles/3.10.2
export CMAKE_FILES_PATH=${BUILD_HOME}/CMakeFiles/$CMAKE_VERSION
export HPFORTIFY_HOME="/Applications/Fortify/Fortify_SCA_and_Apps_20.1.0/bin"
export PATH=$PATH:$ANDROID_SDK_HOME:$ANDROID_NDK_HOME:$ANDROID_CMAKE_HOME:$HPFORTIFY_HOME
echo "[========Start Android JNI C/C++ HP Fortify scanning========]"
echo "[========Build Dir: $BUILD_HOME========]"
echo "[========HP Fortify report path: $FPR========]"
function create_build_folder {
rm -rf $BUILD_HOME
mkdir $BUILD_HOME
}
# The standalone cmake build command can be found from below file.
# JniExample/app/.cxx/cmake/release/x86/build_command.txt
# This file is generated after running command
# `➜ JniExample git:(master) ✗ ./gradlew :app:externalNativeBuildRelease`
function configure_cmake_files {
cd $BUILD_HOME
$ANDROID_CMAKE_HOME/cmake -H$BUILD_HOME/. \
-DCMAKE_CXX_FLAGS=-std=c++11 -frtti -fexceptions \
-DCMAKE_FIND_ROOT_PATH=$BUILD_HOME/.cxx/cmake/release/prefab/x86/prefab \
-DCMAKE_BUILD_TYPE=Release \
-DCMAKE_TOOLCHAIN_FILE=$ANDROID_SDK_HOME/ndk/$NDK_VERSION/build/cmake/android.toolchain.cmake \
-DANDROID_ABI=x86 \
-DANDROID_NDK=$ANDROID_SDK_HOME/ndk/$NDK_VERSION \
-DANDROID_PLATFORM=android-16 \
-DCMAKE_ANDROID_ARCH_ABI=x86 \
-DCMAKE_ANDROID_NDK=$ANDROID_SDK_HOME/ndk/$NDK_VERSION \
-DCMAKE_EXPORT_COMPILE_COMMANDS=ON \
-DCMAKE_LIBRARY_OUTPUT_DIRECTORY=$BUILD_HOME/intermediates/cmake/release/obj/x86 \
-DCMAKE_MAKE_PROGRAM=$ANDROID_SDK_HOME/cmake/$CMAKE_VERSION_PATH/bin/ninja \
-DCMAKE_SYSTEM_NAME=Android \
-DCMAKE_SYSTEM_VERSION=16 \
-B$BUILD_HOME/.cxx/cmake/release/x86 \
-GNinja ..
}
function build {
cmake --build .
}
function cleanup {
rm -rf $BUILD_HOME/CMakeFiles/native-lib.dir
rm -rf $FPR
$HPFORTIFY_HOME/sourceanalyzer -clean
}
function replace_compiler_paths {
FORTIFY_TOOLS_PATH="$WORKING_DIR"
CLANG_PATH="$ANDROID_SDK_HOME/ndk/$NDK_VERSION/toolchains/llvm/prebuilt/darwin-x86_64/bin/clang"
CLANGXX_PATH="$ANDROID_SDK_HOME/ndk/$NDK_VERSION/toolchains/llvm/prebuilt/darwin-x86_64/bin/clang++"
HPFORTIFY_CCPATH="$FORTIFY_TOOLS_PATH/fortify_cc"
HPFORTIFY_CXXPATH="$FORTIFY_TOOLS_PATH/fortify_cxx"\"
sed -i '' 's+'$CLANG_PATH'+'$HPFORTIFY_CCPATH'+g' $CMAKE_FILES_PATH/CMakeCCompiler.cmake
sed -i '' 's+'$CLANG_PATH.*[^")"]'+'$HPFORTIFY_CXXPATH'+g' $CMAKE_FILES_PATH/CMakeCXXCompiler.cmake
}
function scan {
$HPFORTIFY_HOME/sourceanalyzer -b $PROJECTID -scan -f $FPR
# copy the file to $WORKING_DIR
cp $FPR $WORKING_DIR
}
create_build_folder
configure_cmake_files
echo "[========Compile C/C++ using normal compiler ========"]
build
echo "[========Replace the compiler with HP Fortify analyser wrapper compilers ========"]
replace_compiler_paths
echo "[========Clean up the build intermediates and the older build ID and fpr file ========"]
cleanup
echo "[========Recompile C/C++ using HP Fortify analyser wrapper compilers ========"]
build
echo "[========Scan the compiled files and generate final report ========"]
scan
echo "[========Change directory to original working dir ========"]
cd $WORKING_DIR
Need to configure below vars before using it. For my case, I use NDK 21 and CMake 3.10.2 and my project ID is "JNI_EXAMPLE"
# Configure NDK version and CMake version
NDK_VERSION=21.0.6113669
CMAKE_VERSION=3.10.2
CMAKE_VERSION_PATH=$CMAKE_VERSION.4988404
PROJECTID="JNI_EXAMPLE"
# Following exports need to be configured according to host machine.
export ANDROID_SDK_HOME=/Library/Android/sdk
export ANDROID_NDK_HOME=$ANDROID_SDK_HOME/ndk/$NDK_VERSION
export HPFORTIFY_HOME="/Applications/Fortify/Fortify_SCA_and_Apps_20.1.0/bin"
Here is a more detailed explanation: Using HP Fortify to Scan Android JNI C/C++ Code
On recent version of CMake one can use:
CMAKE_<LANG>_COMPILER_LAUNCHER='sourceanalyzer;-b;<PROJECT_ID>'
You can add other arguments (like -Xmx2G for instance), semicolon separated, as mentioned on cmake documentation
You need to check if you don't use the compiler launcher for another tool like ccache. We can probably use both with
CCACHE_PREFIX='.../sourceanalyzer -b ID'
Here is what I've used in CMake project:
project(myFortifiedProject LANGUAGES CXX)
set(CMAKE_CXX_COMPILER_LAUNCHER ${FORTIFY_TOOL} -b ${PROJECT_NAME})
So when running cmake (assuming sourceanalyzer is on the path):
cmake <other args> -DFORTIFY_TOOL=sourceanalyzer
So the normal build command works:
make myFortifiedProject
And you can finally collect results with:
sourceanalyzer -b myFortifiedProject -scan