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
Related
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
I have a package that depends on Rcpp and uses two other libraries compiled from sub-directories in src/. The package builds fine on Mac OSX using a clang compiler. However, on an RStudio Ubuntu server, it fails to build. The build's first two steps (creating the static libraries in the sub directories to link in) work fine and I can see sensible build commands like the following taking place:
g++ -Wall -I../../inst/include/ --std=c++11 -lhts -L../htslib/ -lz -lm -c -o someLibFile.o someLibFile.cpp
However, in the very last step of the build process where it tries to build the Rcpp code and bind to the library, for some reason it appears to compleletey fail to put the compiler command in front (g++) and only outputs the second half of the command.
-o mypackage.so RcppExports.o temp.o -lhts -lpbbam -Lpbbam/ -L/htslib/ -Lpbbam/ -L/mnt/software/r/R/3.1.1/usr/lib/R/lib -lR
In contrast, on the Mac it builds just fine, appending clang++ and other flags in front of this final command:
clang++ -std=c++11 -dynamiclib -Wl,-headerpad_max_install_names -undefined dynamic_lookup -single_module -multiply_defined suppress -L/Library/Frameworks/R.framework/Resources/lib -L/usr/local/lib -o pbbamr.so LoadData.o RcppExports.o temp.o -lhts -lpbbam -Lpbbam/ -Lhtslib/ -Lpbbam/ -F/Library/Frameworks/R.framework/.. -framework R -Wl,-framework -Wl,CoreFoundation
How do I make it use the g++ compiler on Ubuntu at this step? I have a custom Makevars file, but it is there just to build the dependencies in the sub-directory, so I don't know why that would cause any problems (since it works on Mac OSX).
More Information
The compiler seems to be found if I delete my Makevars file. However, the Makevars file I am using is essentially a direct copy of the example given in the R extensions guide with one addition to enable C++11:
CXX_STD = CXX11
.PHONY: all mylibs
all: $(SHLIB)
$(SHLIB): mylibs
mylibs:
(cd subdir; make)
With the line CXX_STD removed, it does stick a compiler in front of the command.
Briefly:
What is your R installation? You should probably run the binaries provided by Michael via CRAN; they are based on my Debian upload; I run these too on a bunch of machines
The reason is that R 'remembers' its compile-time settings via $RHOME/etc/Makefconf. This should just be CXX=g+=.
When you install r-base-dev (from Ubuntu or the newer version from CRAN) you also get the build-essential package as well as all common dependencies. With that things just work.
If however you are doing something special or local, well then you have to deal with your local changes. The basic Ubuntu setup is used by thousands of people and daily jobs--including eg Travis builds for countless GitHub repos.
This is caused by using an outdated/unusual R installation which has poor support for C++11. The best way to resolve his is to upgrade to a more recent version of R, or use a standard R install (sudo apt-get install r-base-dev). A poor work around is described below.
Problems Cause and Bad Work Around
When writing R extension that use C++11, one often sets CXX_STD = CXX11 in the Makevars file or list SystemRequirements: C++11 in the DESCRIPTION file. These will trigger R to use the compiler set by the following flags in the Makeconf file (located at file.path(R.home(), "etc/Makeconf")).
CXX1X
CXX1XFLAGS
CXX1XPICFLAGS
CXX1XSTD
Note that some of these may be set in this file, but not all of them might be there indicating a problem. In the event there is a problem with these settings or they are not set, R appears to use the empty string "" as the compiler/linker for the C++ code, leading to the problem shown above where no compiler argument is given.
If upgrading is not an option and you need to deploy on a known machine, one work around is to manually setup for C++11 by making a more idiosyncratic Makevars file. For example, you could:
Remove the CXX_STD=CXX11 line from the Makevars file.
Remove SystemRequirements: C++11 from the DESCRIPTION file.
Add --std=c++11 and any other requirements needed to PKG_CPPFLAGS, PKG_CFLAGS, PKG_CXXFLAGS or whatever variable is being used to compile your code, to manually set the needed flags (assuming the machine's compiler actually does support C++11).
The above solution is not particularly robust, but can be used as a work around in case the machine cannot be upgraded.
Thanks to #DirkEddelbuettel for not only writing Rcpp but being willing to support it on StackOverflow and help with issues like this.
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 wanted to use latest g++ compiler(4.9.1) on suse linux, but suse only supports an older g++ version. So, I took a latest source code from one of the gnu mirror sites and compiled it myself. Everything went fine. But when I tried to compile my test code using the built g++, the compilation fails with error,
"/root/home/include/c++/4.9.1/x86_64-unknown-linux-gnu/bits/os_defines.h:39:22: fatal error: features.h: No such file or directory".
I can find a "features.h" in "/root/home/include/c++/4.9.1/parallel", but I feel that it should be there in "/root/home/include/c++/4.9.1/" itself.
I copied "/root/home/include/c++/4.9.1/parallel/features.h" to "/root/home/include/c++/4.9.1/" just to see what happens. Now it complains with error "whcar.h" not found.
Have I missed something.
Here are the steps I followed to build g++.
1. /root/home/gcc_build/objdir# ../gcc-4.9.1/configure --prefix=/root/home/ --disable-multilib
2. /root/home/gcc_build/objdir# make -j16
3. /root/home/gcc_build/objdir# make install
4. /root/home/gcc_build/test# /root/home/bin/g++ --sysroot /root/home -m64 test.cpp
I resolved the issue by removing sysroot option and pointing c++ include and library path to my home directory. One thing I noticed was that the g++ source does not come with libc and c header files, and libc has to be installed seperately. But with sysroot option, g++ was trying to look all the header files in my home directory.
Below is the command I used to successfully compile the code.
/root/home/bin/g++ -I /root/home/include/c++/4.9.1 -L /root/home/lib64 -Wl,--rpath=/root/home/lib64 --std=c++0x -m64 test.cpp
Take a look at the GCC Directory Options. It is important to use the correct "specifier" as well (-isystem, -L, -B, -I etc)
I downloaded and built gcc 4.8.1 on my desktop, running 64-bit Ubuntu 12.04. I built it out of source, like the docs recommend, and with the commands
../../gcc-4.8.1/configure --prefix=$HOME --program-suffix=-4.8
make
make -k check
make install
It seemed to pass all the tests, and I installed everything into my home directory w/ the suffix -4.8 to distinguish from the system gcc, which is version 4.6.3.
Unfortunately when I compile c++ programs using g++-4.8 it links to the system libc and libstdc++ rather than the newer ones compiled from gcc-4.8.1. I downloaded and built gcc 4.8 because I wanted to play around with the new C++11 features in the standard library, so this behaviour is definitely not what I wanted. What can I do to get gcc-4.8 to automatically link to the standard libraries that came with it rather than the system standard libraries?
When you link with your own gcc you need to add an extra run-time linker search path(s) with -Wl,-rpath,$(PREFIX)/lib64 so that at run-time it finds the shared libraries corresponding to your gcc.
I normally create a wrapper named gcc and g++ in the same directory as gcc-4.8 and g++-4.8 which I invoke instead of gcc-4.8 and g++-4.8, as prescribed in Dynamic linker is unable to find GCC libraries:
#!/bin/bash
exec ${0}SUFFIX -Wl,-rpath,PREFIX/lib64 "$#"
When installing SUFFIX and PREFIX should be replaced with what was passed to configure:
cd ${PREFIX}/bin && rm -f gcc g++ c++ gfortran
sed -e 's#PREFIX#${PREFIX}#g' -e 's#SUFFIX#${SUFFIX}#g' gcc-wrapper.sh > ${PREFIX}/bin/gcc
chmod +x ${PREFIX}/bin/gcc
cd ${PREFIX}/bin && ln gcc g++ && ln gcc c++ && ln gcc gfortran
(gcc-wrapper.sh is that bash snippet).
The above solution does not work with some versions of libtool because g++ -Wl,... -v assumes linking mode and fails with an error.
A better solution is to use specs file. Once gcc/g++ is built, invoke the following command to make gcc/g++ add -rpath to the linker command line (replace ${PREFIX}/lib64 as necessary):
g++ -dumpspecs | awk '/^\*link:/ { print; getline; print "-rpath=${PREFIX}/lib64", $0; next } { print }' > $(dirname $(g++ -print-libgcc-file-name))/specs
I just had the same problem when building gcc-4.8.2. I don't have root access on that machine and therefore need to install to my home directory. It took several attempts before I figured out the magic required to get this to work so I will reproduce it here so other people will have an easier time. These are the commands that I used to configure gcc:
prefix=/user/grc/packages
export LDFLAGS=-Wl,-rpath,$prefix/lib
export LD_RUN_PATH=$prefix/lib
export LD_LIBRARY_PATH=$prefix/lib
../../src/gmp-4.3.2/configure --prefix=$prefix
../../src/mpfr-2.4.2/configure --prefix=$prefix
../../src/mpc-0.8.1/configure --prefix=$prefix --with-mpfr=$prefix --with-gmp=$prefix
../../src/gcc-4.8.2/configure --prefix=$prefix --with-mpfr=$prefix --with-gmp=$prefix --with-mpc=$prefix --enable-languages=c,c++
That got me a working binary but any program I built with that version of g++ wouldn't run correctly unless I built it with the -Wl,-rpath,$prefix/lib64 option. It is possible to get g++ to automatically add that option by providing a specs file. If you run
strace g++ 2>&1 | grep specs
you can see which directories it checks for a specs file. In my case it was $prefix/lib/gcc/x86_64-unknown-linux-gnu/4.8.2/specs so I ran g++ -dumpspecs to create a new specs file:
cd $prefix/lib/gcc/x86_64-unknown-linux-gnu/4.8.2
$prefix/bin/g++ -dumpspecs > xx
mv xx specs
and then edited that file to provide the -rpath option. Search for the lines like this:
*link_libgcc:
%D
and edit to add the rpath option:
*link_libgcc:
%D -rpath /user/grc/packages/lib/%M
The %M expands to either ../lib or ../lib64 depending on whether you are building a 32-bit or a 64-bit executable.
Note that when I tried this same trick on an older gcc-4.7 build it didn't work because it didn't expand the %M. For older versions you can remove the %M and just hardcode lib or lib64 but that is only a viable solution if you only ever build 32-bit executables (with lib) or only ever build 64-bit executables (with lib64).
gcc -print-search-dirs will tell you where your compiler is looking for runtime libraries, etc. You can override this with the -B<prefix> option.