I'm using gnu autotools with my project in C++ (the autotools config is automatically generated by eclipse cdt, but this does not matter i think). I'm using LLVM libs and right now I'm facing a problem with order of linker flags.
Basically, when building a project, eclipse executes "make". Make executes a lot of commands, but lastly it executes g++ compiler as follows:
g++ -DPACKAGE_NAME=\"test\" -DPACKAGE_TARNAME=\"test\" -DPACKAGE_VERSION=\"1.0\" -DPACKAGE_STRING=\"test\ 1.0\" -DPACKAGE_BUGREPORT=\"\" -DPACKAGE_URL=\"\" -DPACKAGE=\"test\" -DVERSION=\"1.0\" -I. `llvm-config --cppflags --ldflags --libs core` -g -O2 -MT test.o -MD -MP -MF .deps/test.Tpo -c -o test.o test.cpp
mv -f .deps/test.Tpo .deps/test.Po
and then the linker:
g++ `llvm-config --cppflags --ldflags --libs core` -g -O2 -o a.out test.o
The problem is, that the linker fails if the argument "test.o" is not on the beginning of line, so it should be:
g++ test.o `llvm-config --cppflags --ldflags --libs core` -g -O2 -o a.out
How to change it in Makefile.am or any config file for gnu autotools?
I didn't found the answer, but so far I have found out that LLVM is bundled with a project template containing custom automake system, which handles all the stuff the correct way.
If you want to access the template, you can find it in $LLVMSRC/projects/sample folder.
Related
To follow Kaleidoscope tutorial part 4, I downloaded the header file KaleidoscopeJIT.h. But once I include it, I get the following error
$ clang++ -g main.cpp kaleidoscope.cpp `llvm-config --cxxflags --ldflags --system-libs --libs core orcjit native` -O3 -o kaleidoscope
In file included from kaleidoscope.cpp:18:
././include/KaleidoscopeJIT.h:21:10: fatal error: 'llvm/ExecutionEngine/Orc/ExecutorProcessControl.h' file not found
#include "llvm/ExecutionEngine/Orc/ExecutorProcessControl.h"
The closest information to it I could find at documentation page, but there is no information on how to successfully compile it. Any suggestions on how to resolve header dependency?
Here are my config options,
$ llvm-config --cxxflags --ldflags --system-libs --libs core orcjit native
-I/usr/lib/llvm-10/include -std=c++14 -fno-exceptions -D_GNU_SOURCE -D__STDC_CONSTANT_MACROS -D__STDC_FORMAT_MACROS -D__STDC_LIMIT_MACROS
-L/usr/lib/llvm-10/lib
-lLLVM-10
Make sure you pull the correct files. You are using llvm-10 so you need to use the kaleidoscope tutorial from that version.
I was building some Cython extensions, and have to link it against a static library (it has CUDA code in them, so have to be static):
running build_ext
building 'k3lib' extension
gcc -pthread -B /home/kelvin/anaconda3/envs/torch/compiler_compat -Wl,--sysroot=/ -Wsign-compare -DNDEBUG -g -fwrapv -O3 -Wall -Wstrict-prototypes -fPIC -I/home/kelvin/repos/tools/include -I/home/kelvin/anaconda3/envs/torch/include/python3.8 -c main.cpp -o build/temp.linux-x86_64-3.8/main.o -O3 -march=native
cc1plus: warning: command line option ‘-Wstrict-prototypes’ is valid for C/ObjC but not for C++
g++ -pthread -shared -B /home/kelvin/anaconda3/envs/torch/compiler_compat -L/home/kelvin/anaconda3/envs/torch/lib -Wl,-rpath=/home/kelvin/anaconda3/envs/torch/lib -Wl,--no-as-needed -Wl,--sysroot=/ build/temp.linux-x86_64-3.8/main.o /home/kelvin/repos/tools/include/libk2.a -L/home/kelvin/repos/tools/include -lk2 -o build/lib.linux-x86_64-3.8/k3lib.cpython-38-x86_64-linux-gnu.so -static -Wl,-Bstatic -flinker-output=exec
However, Cython's g++ compile command includes the options -shared -fPIC by default. I tried a number of options at the end of the command via this setup file (the static library is at $(LOCAL_INCLUDE)/libk2.a):
includes = [os.getenv("LOCAL_INCLUDE")]
ext_modules = [
Extension("k3lib", sources=["main.pyx"],
libraries=["k2"], include_dirs=includes, library_dirs=includes, language="c++",
extra_compile_args=["-O3", "-march=native"], extra_objects=[f"{includes[0]}/libk2.a"],
extra_link_args=['-static', '-Wl,-Bstatic', '-flinker-output=exec'])
]
#extra_objects=[f"{includes[0]}/libk2.a"]
#extra_link_args=['-static']
setup(name="k3lib", ext_modules=cythonize(ext_modules, language_level="3"))
Still, g++ thinks that I want to build a shared library, and thus the error message. Is there a way to override the -shared option? I'm planning to go into Cython's files and edit them myself, but was wondering is there a simpler way?
Context: I was following this question on SO but can't replicate their success.
I'm trying to statically link glibc in order to run my application on an older OS, but when I use the -static flag I get "undefined reference" errors for other libraries I'm using that I don't get without using -static. How do I fix this issue?
My Makefile produces the following commands:
g++ -static -Wall -O3 -w -std=c++11 -I/storage/home/PA/libs -I/storage/home/PA/libs/xerces -fopenmp -c Utilities.cpp
gcc -static -Wall -O3 -w -std=c++11 -I/storage/home/PA/libs -I/storage/home/PA/libs/xerces -fopenmp -c ccvt.c
gcc -static -Wall -O3 -w -std=c++11 -I/storage/home/PA/libs -I/storage/home/PA/libs/xerces -fopenmp -c client.c
g++ -static -Wall -O3 -w -std=c++11 -I/storage/home/PA/libs -I/storage/home/PA/libs/xerces -fopenmp -c XML_Params.cpp
g++ -static -Wall -O3 -w -std=c++11 -I/storage/home/PA/libs -I/storage/home/PA/libs/xerces -fopenmp -c main.cpp
g++ -static -Wall -O3 -std=c++11 -L/storage/home/PA/libs/gsl -fopenmp -lgsl -lgslcblas -lm -L/storage/home/PA/libs/xerces -lxerces-c -o App main.o Utilities.o XML_Params.o ccvt.o client.o
After the last line I get a huge wall of errors complaining about undefined references to Xerces and gsl functions. However, if I remove the -static from the makefile, everything builds fine. What is the proper way to link these libraries when I'm using -static?
according to gcc manual:
-llibrary
It makes a difference where in the command you write this option; the
linker searches and processes libraries and object files in the order
they are specified. Thus, foo.o -lz bar.o searches library z after
file foo.o but before bar.o. If bar.o refers to functions in z,
those functions may not be loaded.
Move -lxerces after *.o might solve your problem.
I think you don't need to add -static except for the last line, correct me if i'm wrong.
I have a project that is compiled with autotools and up until this week needed to be only compiled with OpenMP and MPI support. I have now added a CUDA kernel that I wish to compile into the code under certain circumstances. The compiling of the code goes okay and all of the object files are created. When it comes to linking the objects into the executable the following command is used:
/bin/bash ../libtool --tag=CXX --mode=link nvcc -ccbin=mpicxx -I/usr/local/cuda/include -Xcompiler -std=c++0x -Xcompiler -fopenmp -L/usr/local/cuda/lib64 -lcuda -lcudart -lcufft -o utrplauncher utrplauncher-UTRP.o crossovers/libcrossovers.a initialisers/libinitialisers.a mutators/libmutators.a problem/libproblem.a common/libcommon.a variables/libvariables.a ../libraries/framework/libmoeaframework.a ../libraries/ticpp/libticpp.a
Which in turn generates the follwong link command
libtool: link: nvcc -ccbin=mpicxx -I/usr/local/cuda/include -std=c++0x -fopenmp -o utrplauncher utrplauncher-UTRP.o -L/usr/local/cuda/lib64 -lcuda -lcudart -lcufft crossovers/libcrossovers.a initialisers/libinitialisers.a mutators/libmutators.a problem/libproblem.a common/libcommon.a variables/libvariables.a ../libraries/framework/libmoeaframework.a ../libraries/ticpp/libticpp.a
This the generates the following error because the -std=c++0x and -fopenmp are interpreted by the CUDA compiler and not the mpicxx compiler.
nvcc fatal : Value 'c++0x' is not defined for option 'std'
I can post my configure.ac if that would help but wanted to keep the question concise at the moment.
My question is therefore is it possible to forward the -Xcompiler flags to the mpicxx compiler rather than having them stripped off by libtool?
One way is to pass both -Xcompiler=-std=c++0x and -Xcompiler=-fopenmp directly to the compiler using -Wc,, thus -Xcompiler is not stripped by libtool. For instance following dry-run:
libtool -n --tag=CXX --mode=link nvcc
-ccbin=mpicxx-I/usr/local/cuda/include -Wc,-Xcompiler=-std=c++0x -Wc,-Xcompiler=-fopenmp -L/usr/local/cuda/lib64 -lcuda -lcudart -lcufft -o utrplauncher utrplauncher-UTRP.o crossovers/libcrossovers.a initialisers/libinitialisers.a mutators/libmutators.a
problem/libproblem.a common/libcommon.a variables/libvariables.a
../libraries/framework/libmoeaframework.a
../libraries/ticpp/libticpp.a
generates:
libtool: link: nvcc -ccbin=mpicxx-I/usr/local/cuda/include
-Xcompiler=-std=c++0x -Xcompiler=-fopenmp -o utrplauncher utrplauncher-UTRP.o -L/usr/local/cuda/lib64 -lcuda -lcudart -lcufft
crossovers/libcrossovers.a initialisers/libinitialisers.a
mutators/libmutators.a problem/libproblem.a common/libcommon.a
variables/libvariables.a ../libraries/framework/libmoeaframework.a
../libraries/ticpp/libticpp.a
I'm trying to compile this (also listed in the mysql c++ connector documentation): http://pastebin.com/HLv4zR0r
But I get these errors: http://pastebin.com/3t0UbeFy
This is how I tried compiling:
g++ -o test test.cpp `mysql_config --cflags --libs` -I./include/cppconn -L./lib -lmysqlcppconn-static
The result of running mysql_config --cflags --libs is:
-I/usr/include/mysql -DBIG_JOINS=1 -fno-strict-aliasing -g
-L/usr/lib/x86_64-linux-gnu -lmysqlclient -lpthread -lz -lm -lrt -ldl
Edit:
After running Jonathan Wakely's suggested command with properly-ordered linker arguments,
g++ -o test test.cpp -I./include/cppconn -L./lib -lmysqlcppconn-static `mysql_config --cflags --libs`
I get different errors: http://pastebin.com/4EWNgy9i
The mysqlcppcon library depends on the mysqlclient C libraries, so you need to put the mysqlclient libs after -lmysqlcppconn-static
g++ -o test test.cpp -I./include/cppconn -L./lib -lmysqlcppconn-static `mysql_config --cflags --libs`
The order of linker arguments matters. The linker looks at each file in order and decides if it needs any symbols from it. By the time it sees the libmysqlcppconn-static.a file it has already looked at (and ignored) the libmysqlclient.so library, and doesn't go back to look at it again.