I have c and c++ project, and i would like to check for dead function (function that could not be called), for that i want to build a call graph and see which could not be accessed from the written code.
for that i want to use clang with the flag "-S -emit-llvm" so i could creat a dot file.
im using autoconf to compile the project and the autoconfig dont recognize the file that has been compiled as an executable.
tried using this line :
./configure --enable-debug --prefix=/opt/ibutils CC=clang CXX=clang++ CXXFLAGS="-S -emit-llvm"
and this
./configure --enable-debug --prefix=/opt/ibutils CC=clang CXX=clang++ CXXFLAGS="-S -emit-llvm"
LD="llvm-link"
does anyone know the reason? have a suggestions what could i do?
thanks
Related
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 have 2 cpp files(with one main function) in /home/misha/proga/c++again folder. I built C/C++: g++ build active task and modified it to compile all files in the folder above. Now, I need to add one more task to call a binary. I think I should add one more entry in "tasks" to finally be able to run a code. Where can I read about how to write this second task? I am new to programming. Is my approach correct to run this code contained in two files? I also do not know where this binary lies. Is it tasks file in .vscode folder ?
I use Ubuntu 19.10 and VSC 1.46.1
In Terminal,
cd /home/misha/proga/c++again
Let's suppose your two cpp files are mainFile.cpp and file2.cpp
If g++ (so GCC) was not installed in your system, you can install it by running this command on the Terminal:
sudo apt-get install gcc g++
and, to compile the program (read about invoking GCC, you want warnings and debug information), write this command into the Terminal:
g++ -Wall -g mainFile.cpp file2.cpp -o yourprog
Then, you can run the program by typing:
./yourprog
It should work now. You could need to use the GDB debugger and GNU make (to be installed with sudo apt-get install gdb make)
Read also some C++ programming book and this C++ reference.
I do not understand your approach usualy your create a makefile and compile your cpp files
g++ -g -c -fpic -o name.o
at the end you link them
g++ name.o 2name.o and so on
If you create binarys you should store them in /usr/lib
and the name should libname.so you can acces them by using the -l argument
So I follow the official tutorial for the installation : https://mongodb.github.io/mongo-cxx-driver/mongocxx-v3/installation/
Neverless, I can't use the produced libraries as static.
So I managed to compile the C version of the driver as described, I've enabled the flag --enable-static=yes with the ./configure before doing make && sudo make install and I got the libmongoc-1.0.a and the libbson-1.0.a which are static. So this far, everything it's alright.
Then I have done the cxx version of the driver, except that there is no configuration file as in the C version. So I've juste done a
cmake -DCMAKE_BUILD_TYPE=Release -DBSONCXX_POLY_USE_BOOST=1 -DCMAKE_INSTALL_PREFIX=/usr/local
from the build folder, followed by a make && sudo make install
So I got the libmongocxx.a and the libbsoncxx.a, but when I try to compile with them, I can't run the binary because I got the following error :
error while loading shared libraries: libmongocxx.so._noabi: cannot open shared object file: No such file or directory
So I understand that is because there is some symbols missing and then I need to use the shared library to run the binary but I don't want this to happend, I want the symbols within the binary that I can run it without any LD_PRELOAD.
Any suggestions ?
I had the same issue in an Ubuntu 16.04 and I run a apt-get update & apt-get upgrade and the problem was solved.
It seems that there were some update to the compiler and some libraries that prevent some test from reaching the shared libraries.
I have a similar question, and solved, now I compiled and run my binary with static libs successfully.
I write my build script using newlisp, but the static link options are very helpful, I paste it here.
c++ /to/your/path/site/code/back_end/builder/object/files1.cc.o ... /to/your/path/site/code/back_end/builder/object/files10.cc.o -o bin/site -static-libgcc -static-libstdc++ -L/usr/lib -lpthread -l:libmongocxx.a -l:libbsoncxx.a -l:libmongoc-1.0.a -l:libbson-1.0.a -lrt -lssl -lcrypto -lsasl2 -l:libboost_log.a -l:libboost_log_setup.a -l:libboost_system.a -l:libboost_thread.a -l:libboost_filesystem.a -lcppcms -lbooster -lcurl -ljsoncpp
I am trying to compile the code for one of the projects and the source file uses autoreconf for generating the makefiles.
" autoreconf --verbose --force --make "
The problem is that this somehow generates the makefiles that uses the compiler as GCC. I want it to generate the configuration files with a different compiler. How can I do it?
I can issue the command as make CC= but this throws an error in the libtool that is used later on.
Thank You
Typically autoreconf just regenerates the configure script and the autoconf makefile templates, it doesn't create any actual makefiles.
Makefiles get created when configure is run, and that's when you want to override the compiler:
configure CC=clang CXX=clang++
that should create makefiles that use CC=clang and CXX=clang++
I am trying to build GNU Coreutils 8.23 using the LLVM 3.4 tool-chain. One very important aspect is that I also need the LLVM bytecode for all the coreutils. Therefore, I need to include -emit-llvm in the CFLAGS. Therefore, I removed the $(CFLAGS) from the LINK variable of the coreutils Makefile. Afterwards, I run the following command:
make CC=/home/user/llvm-3.4.2/build/Release+Asserts/bin/clang
CCLD=/home/user/llvm-3.4.2/build/Release+Asserts/bin/llvm-link
IGNORE_UNUSED_LIBRARIES_CFLAGS= CFLAGS="-emit-llvm -S"
VERBOSE=1 AM_CFLAGS= AM_LDFLAGS=
AR=/home/user/llvm-3.4.2/build/Release+Asserts/bin/llvm-ar
RANLIB=/home/user/llvm-3.4.2/build/Release+Asserts/bin/llvm-ranlib
and I get the following error:
/home/user/llvm-3.4.2/build/Release+Asserts/bin/llvm-link: src/libver.a:1:2: error: expected integer
!<arch>
^
/home/user/llvm-3.4.2/build/Release+Asserts/bin/llvm-link: error loading file 'src/libver.a'
Any ideas of how to get this to work?
Try this.
export CC="/home/user/llvm-3.4.2/build/Release+Asserts/bin/clang"
export CXX="/home/user/llvm-3.4.2/build/Release+Asserts/bin/clang++"
Make sure this is where your compiler toolchain is present.
Then in the the coreutils directory, run ./configure (before this run ./bootstrap if you havent already run it). Running ./configure checks if your clang can compile properly and creates a Makefile with the correct configuration.
Then do a make and make install as instructed.
Lib file '.a' here is not readable by llvm-link.
A possible informal hack to this probably is to find out the Makefile generating this lib, and let
AR = llvm-link, ar option = -o(i.e. change ar rv to llvm-link -o),
and disable ranlib command while compling(you don't need ranlib if using llvm-link).
Then the '.a' file generated is a stitched bc file, and this '.a' file should be accpetable by llvm-link command you are calling